diff options
| -rw-r--r-- | Documentation/filesystems/00-INDEX | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/logfs.txt | 241 | ||||
| -rw-r--r-- | fs/Kconfig | 1 | ||||
| -rw-r--r-- | fs/Makefile | 1 | ||||
| -rw-r--r-- | fs/logfs/Kconfig | 17 | ||||
| -rw-r--r-- | fs/logfs/Makefile | 13 | ||||
| -rw-r--r-- | fs/logfs/compr.c | 95 | ||||
| -rw-r--r-- | fs/logfs/dev_bdev.c | 263 | ||||
| -rw-r--r-- | fs/logfs/dev_mtd.c | 253 | ||||
| -rw-r--r-- | fs/logfs/dir.c | 818 | ||||
| -rw-r--r-- | fs/logfs/file.c | 263 | ||||
| -rw-r--r-- | fs/logfs/gc.c | 730 | ||||
| -rw-r--r-- | fs/logfs/inode.c | 417 | ||||
| -rw-r--r-- | fs/logfs/journal.c | 879 | ||||
| -rw-r--r-- | fs/logfs/logfs.h | 722 | ||||
| -rw-r--r-- | fs/logfs/logfs_abi.h | 627 | ||||
| -rw-r--r-- | fs/logfs/readwrite.c | 2246 | ||||
| -rw-r--r-- | fs/logfs/segment.c | 924 | ||||
| -rw-r--r-- | fs/logfs/super.c | 634 | ||||
| -rw-r--r-- | include/linux/btree-128.h | 109 | ||||
| -rw-r--r-- | include/linux/btree-type.h | 147 | ||||
| -rw-r--r-- | include/linux/btree.h | 243 | ||||
| -rw-r--r-- | lib/Kconfig | 3 | ||||
| -rw-r--r-- | lib/Makefile | 1 | ||||
| -rw-r--r-- | lib/btree.c | 797 |
25 files changed, 10446 insertions, 0 deletions
diff --git a/Documentation/filesystems/00-INDEX b/Documentation/filesystems/00-INDEX index f15621ee559..d362aa543b2 100644 --- a/Documentation/filesystems/00-INDEX +++ b/Documentation/filesystems/00-INDEX @@ -62,6 +62,8 @@ jfs.txt - info and mount options for the JFS filesystem. locks.txt - info on file locking implementations, flock() vs. fcntl(), etc. +logfs.txt + - info on the LogFS flash filesystem. mandatory-locking.txt - info on the Linux implementation of Sys V mandatory file locking. ncpfs.txt diff --git a/Documentation/filesystems/logfs.txt b/Documentation/filesystems/logfs.txt new file mode 100644 index 00000000000..e64c94ba401 --- /dev/null +++ b/Documentation/filesystems/logfs.txt @@ -0,0 +1,241 @@ + +The LogFS Flash Filesystem +========================== + +Specification +============= + +Superblocks +----------- + +Two superblocks exist at the beginning and end of the filesystem. +Each superblock is 256 Bytes large, with another 3840 Bytes reserved +for future purposes, making a total of 4096 Bytes. + +Superblock locations may differ for MTD and block devices. On MTD the +first non-bad block contains a superblock in the first 4096 Bytes and +the last non-bad block contains a superblock in the last 4096 Bytes. +On block devices, the first 4096 Bytes of the device contain the first +superblock and the last aligned 4096 Byte-block contains the second +superblock. + +For the most part, the superblocks can be considered read-only. They +are written only to correct errors detected within the superblocks, +move the journal and change the filesystem parameters through tunefs. +As a result, the superblock does not contain any fields that require +constant updates, like the amount of free space, etc. + +Segments +-------- + +The space in the device is split up into equal-sized segments. +Segments are the primary write unit of LogFS. Within each segments, +writes happen from front (low addresses) to back (high addresses. If +only a partial segment has been written, the segment number, the +current position within and optionally a write buffer are stored in +the journal. + +Segments are erased as a whole. Therefore Garbage Collection may be +required to completely free a segment before doing so. + +Journal +-------- + +The journal contains all global information about the filesystem that +is subject to frequent change. At mount time, it has to be scanned +for the most recent commit entry, which contains a list of pointers to +all currently valid entries. + +Object Store +------------ + +All space except for the superblocks and journal is part of the object +store. Each segment contains a segment header and a number of +objects, each consisting of the object header and the payload. +Objects are either inodes, directory entries (dentries), file data +blocks or indirect blocks. + +Levels +------ + +Garbage collection (GC) may fail if all data is written +indiscriminately. One requirement of GC is that data is seperated +roughly according to the distance between the tree root and the data. +Effectively that means all file data is on level 0, indirect blocks +are on levels 1, 2, 3 4 or 5 for 1x, 2x, 3x, 4x or 5x indirect blocks, +respectively. Inode file data is on level 6 for the inodes and 7-11 +for indirect blocks. + +Each segment contains objects of a single level only. As a result, +each level requires its own seperate segment to be open for writing. + +Inode File +---------- + +All inodes are stored in a special file, the inode file. Single +exception is the inode file's inode (master inode) which for obvious +reasons is stored in the journal instead. Instead of data blocks, the +leaf nodes of the inode files are inodes. + +Aliases +------- + +Writes in LogFS are done by means of a wandering tree. A naïve +implementation would require that for each write or a block, all +parent blocks are written as well, since the block pointers have +changed. Such an implementation would not be very efficient. + +In LogFS, the block pointer changes are cached in the journal by means +of alias entries. Each alias consists of its logical address - inode +number, block index, level and child number (index into block) - and +the changed data. Any 8-byte word can be changes in this manner. + +Currently aliases are used for block pointers, file size, file used +bytes and the height of an inodes indirect tree. + +Segment Aliases +--------------- + +Related to regular aliases, these are used to handle bad blocks. +Initially, bad blocks are handled by moving the affected segment +content to a spare segment and noting this move in the journal with a +segment alias, a simple (to, from) tupel. GC will later empty this +segment and the alias can be removed again. This is used on MTD only. + +Vim +--- + +By cleverly predicting the life time of data, it is possible to +seperate long-living data from short-living data and thereby reduce +the GC overhead later. Each type of distinc life expectency (vim) can +have a seperate segment open for writing. Each (level, vim) tupel can +be open just once. If an open segment with unknown vim is encountered +at mount time, it is closed and ignored henceforth. + +Indirect Tree +------------- + +Inodes in LogFS are similar to FFS-style filesystems with direct and +indirect block pointers. One difference is that LogFS uses a single +indirect pointer that can be either a 1x, 2x, etc. indirect pointer. +A height field in the inode defines the height of the indirect tree +and thereby the indirection of the pointer. + +Another difference is the addressing of indirect blocks. In LogFS, +the first 16 pointers in the first indirect block are left empty, +corresponding to the 16 direct pointers in the inode. In ext2 (maybe +others as well) the first pointer in the first indirect block +corresponds to logical block 12, skipping the 12 direct pointers. +So where ext2 is using arithmetic to better utilize space, LogFS keeps +arithmetic simple and uses compression to save space. + +Compression +----------- + +Both file data and metadata can be compressed. Compression for file +data can be enabled with chattr +c and disabled with chattr -c. Doing +so has no effect on existing data, but new data will be stored +accordingly. New inodes will inherit the compression flag of the +parent directory. + +Metadata is always compressed. However, the space accounting ignores +this and charges for the uncompressed size. Failing to do so could +result in GC failures when, after moving some data, indirect blocks +compress worse than previously. Even on a 100% full medium, GC may +not consume any extra space, so the compression gains are lost space +to the user. + +However, they are not lost space to the filesystem internals. By +cheating the user for those bytes, the filesystem gained some slack +space and GC will run less often and faster. + +Garbage Collection and Wear Leveling +------------------------------------ + +Garbage collection is invoked whenever the number of free segments +falls below a threshold. The best (known) candidate is picked based +on the least amount of valid data contained in the segment. All +remaining valid data is copied elsewhere, thereby invalidating it. + +The GC code also checks for aliases and writes then back if their +number gets too large. + +Wear leveling is done by occasionally picking a suboptimal segment for +garbage collection. If a stale segments erase count is significantly +lower than the active segments' erase counts, it will be picked. Wear +leveling is rate limited, so it will never monopolize the device for +more than one segment worth at a time. + +Values for "occasionally", "significantly lower" are compile time +constants. + +Hashed directories +------------------ + +To satisfy efficient lookup(), directory entries are hashed and +located based on the hash. In order to both support large directories +and not be overly inefficient for small directories, several hash +tables of increasing size are used. For each table, the hash value +modulo the table size gives the table index. + +Tables sizes are chosen to limit the number of indirect blocks with a +fully populated table to 0, 1, 2 or 3 respectively. So the first +table contains 16 entries, the second 512-16, etc. + +The last table is special in several ways. First its size depends on +the effective 32bit limit on telldir/seekdir cookies. Since logfs +uses the upper half of the address space for indirect blocks, the size +is limited to 2^31. Secondly the table contains hash buckets with 16 +entries each. + +Using single-entry buckets would result in birthday "attacks". At +just 2^16 used entries, hash collisions would be likely (P >= 0.5). +My math skills are insufficient to do the combinatorics for the 17x +collisions necessary to overflow a bucket, but testing showed that in +10,000 runs the lowest directory fill before a bucket overflow was +188,057,130 entries with an average of 315,149,915 entries. So for +directory sizes of up to a million, bucket overflows should be +virtually impossible under normal circumstances. + +With carefully chosen filenames, it is obviously possible to cause an +overflow with just 21 entries (4 higher tables + 16 entries + 1). So +there may be a security concern if a malicious user has write access +to a directory. + +Open For Discussion +=================== + +Device Address Space +-------------------- + +A device address space is used for caching. Both block devices and +MTD provide functions to either read a single page or write a segment. +Partial segments may be written for data integrity, but where possible +complete segments are written for performance on simple block device +flash media. + +Meta Inodes +----------- + +Inodes are stored in the inode file, which is just a regular file for +most purposes. At umount time, however, the inode file needs to +remain open until all dirty inodes are written. So +generic_shutdown_super() may not close this inode, but shouldn't +complain about remaining inodes due to the inode file either. Same +goes for mapping inode of the device address space. + +Currently logfs uses a hack that essentially copies part of fs/inode.c +code over. A general solution would be preferred. + +Indirect block mapping +---------------------- + +With compression, the block device (or mapping inode) cannot be used +to cache indirect blocks. Some other place is required. Currently +logfs uses the top half of each inode's address space. The low 8TB +(on 32bit) are filled with file data, the high 8TB are used for +indirect blocks. + +One problem is that 16TB files created on 64bit systems actually have +data in the top 8TB. But files >16TB would cause problems anyway, so +only the limit has changed. diff --git a/fs/Kconfig b/fs/Kconfig index 64d44efad7a..7405f071be6 100644 --- a/fs/Kconfig +++ b/fs/Kconfig @@ -177,6 +177,7 @@ source "fs/efs/Kconfig" source "fs/jffs2/Kconfig" # UBIFS File system configuration source "fs/ubifs/Kconfig" +source "fs/logfs/Kconfig" source "fs/cramfs/Kconfig" source "fs/squashfs/Kconfig" source "fs/freevxfs/Kconfig" diff --git a/fs/Makefile b/fs/Makefile index af6d04700d9..c3633aa4691 100644 --- a/fs/Makefile +++ b/fs/Makefile @@ -99,6 +99,7 @@ obj-$(CONFIG_NTFS_FS) += ntfs/ obj-$(CONFIG_UFS_FS) += ufs/ obj-$(CONFIG_EFS_FS) += efs/ obj-$(CONFIG_JFFS2_FS) += jffs2/ +obj-$(CONFIG_LOGFS) += logfs/ obj-$(CONFIG_UBIFS_FS) += ubifs/ obj-$(CONFIG_AFFS_FS) += affs/ obj-$(CONFIG_ROMFS_FS) += romfs/ diff --git a/fs/logfs/Kconfig b/fs/logfs/Kconfig new file mode 100644 index 00000000000..daf9a9b32dd --- /dev/null +++ b/fs/logfs/Kconfig @@ -0,0 +1,17 @@ +config LOGFS + tristate "LogFS file system (EXPERIMENTAL)" + depends on (MTD || BLOCK) && EXPERIMENTAL + select ZLIB_INFLATE + select ZLIB_DEFLATE + select CRC32 + select BTREE + help + Flash filesystem aimed to scale efficiently to large devices. + In comparison to JFFS2 it offers significantly faster mount + times and potentially less RAM usage, although the latter has + not been measured yet. + + In its current state it is still very experimental and should + not be used for other than testing purposes. + + If unsure, say N. diff --git a/fs/logfs/Makefile b/fs/logfs/Makefile new file mode 100644 index 00000000000..4820027787e --- /dev/null +++ b/fs/logfs/Makefile @@ -0,0 +1,13 @@ +obj-$(CONFIG_LOGFS) += logfs.o + +logfs-y += compr.o +logfs-y += dir.o +logfs-y += file.o +logfs-y += gc.o +logfs-y += inode.o +logfs-y += journal.o +logfs-y += readwrite.o +logfs-y += segment.o +logfs-y += super.o +logfs-$(CONFIG_BLOCK) += dev_bdev.o +logfs-$(CONFIG_MTD) += dev_mtd.o diff --git a/fs/logfs/compr.c b/fs/logfs/compr.c new file mode 100644 index 00000000000..44bbfd249ab --- /dev/null +++ b/fs/logfs/compr.c @@ -0,0 +1,95 @@ +/* + * fs/logfs/compr.c - compression routines + * + * As should be obvious for Linux kernel code, license is GPLv2 + * + * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org> + */ +#include "logfs.h" +#include <linux/vmalloc.h> +#include <linux/zlib.h> + +#define COMPR_LEVEL 3 + +static DEFINE_MUTEX(compr_mutex); +static struct z_stream_s stream; + +int logfs_compress(void *in, void *out, size_t inlen, size_t outlen) +{ + int err, ret; + + ret = -EIO; + mutex_lock(&compr_mutex); + err = zlib_deflateInit(&stream, COMPR_LEVEL); + if (err != Z_OK) + goto error; + + stream.next_in = in; + stream.avail_in = inlen; + stream.total_in = 0; + stream.next_out = out; + stream.avail_out = outlen; + stream.total_out = 0; + + err = zlib_deflate(&stream, Z_FINISH); + if (err != Z_STREAM_END) + goto error; + + err = zlib_deflateEnd(&stream); + if (err != Z_OK) + goto error; + + if (stream.total_out >= stream.total_in) + goto error; + + ret = stream.total_out; +error: + mutex_unlock(&compr_mutex); + return ret; +} + +int logfs_uncompress(void *in, void *out, size_t inlen, size_t outlen) +{ + int err, ret; + + ret = -EIO; + mutex_lock(&compr_mutex); + err = zlib_inflateInit(&stream); + if (err != Z_OK) + goto error; + + stream.next_in = in; + stream.avail_in = inlen; + stream.total_in = 0; + stream.next_out = out; + stream.avail_out = outlen; + stream.total_out = 0; + + err = zlib_inflate(&stream, Z_FINISH); + if (err != Z_STREAM_END) + goto error; + + err = zlib_inflateEnd(&stream); + if (err != Z_OK) + goto error; + + ret = 0; +error: + mutex_unlock(&compr_mutex); + return ret; +} + +int __init logfs_compr_init(void) +{ + size_t size = max(zlib_deflate_workspacesize(), + zlib_inflate_workspacesize()); + stream.workspace = vmalloc(size); + if (!stream.workspace) + return -ENOMEM; + return 0; +} + +void logfs_compr_exit(void) +{ + vfree(stream.workspace); +} diff --git a/fs/logfs/dev_bdev.c b/fs/logfs/dev_bdev.c new file mode 100644 index 00000000000..58a057b6e1a --- /dev/null +++ b/fs/logfs/dev_bdev.c @@ -0,0 +1,263 @@ +/* + * fs/logfs/dev_bdev.c - Device access methods for block devices + * + * As should be obvious for Linux kernel code, license is GPLv2 + * + * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org> + */ +#include "logfs.h" +#include <linux/bio.h> +#include <linux/blkdev.h> +#include <linux/buffer_head.h> + +#define PAGE_OFS(ofs) ((ofs) & (PAGE_SIZE-1)) + +static void request_complete(struct bio *bio, int err) +{ + complete((struct completion *)bio->bi_private); +} + +static int sync_request(struct page *page, struct block_device *bdev, int rw) +{ + struct bio bio; + struct bio_vec bio_vec; + struct completion complete; + + bio_init(&bio); + bio.bi_io_vec = &bio_vec; + bio_vec.bv_page = page; + bio_vec.bv_len = PAGE_SIZE; + bio_vec.bv_offset = 0; + bio.bi_vcnt = 1; + bio.bi_idx = 0; + bio.bi_size = PAGE_SIZE; + bio.bi_bdev = bdev; + bio.bi_sector = page->index * (PAGE_SIZE >> 9); + init_completion(&complete); + bio.bi_private = &complete; + bio.bi_end_io = request_complete; + + submit_bio(rw, &bio); + generic_unplug_device(bdev_get_queue(bdev)); + wait_for_completion(&complete); + return test_bit(BIO_UPTODATE, &bio.bi_flags) ? 0 : -EIO; +} + +static int bdev_readpage(void *_sb, struct page *page) +{ + struct super_block *sb = _sb; + struct block_device *bdev = logfs_super(sb)->s_bdev; + int err; + + err = sync_request(page, bdev, READ); + if (err) { + ClearPageUptodate(page); + SetPageError(page); + } else { + SetPageUptodate(page); + ClearPageError(page); + } + unlock_page(page); + return err; +} + +static DECLARE_WAIT_QUEUE_HEAD(wq); + +static void writeseg_end_io(struct bio *bio, int err) +{ + const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); + struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1; + struct super_block *sb = bio->bi_private; + struct logfs_super *super = logfs_super(sb); + struct page *page; + + BUG_ON(!uptodate); /* FIXME: Retry io or write elsewhere */ + BUG_ON(err); + BUG_ON(bio->bi_vcnt == 0); + do { + page = bvec->bv_page; + if (--bvec >= bio->bi_io_vec) + prefetchw(&bvec->bv_page->flags); + + end_page_writeback(page); + } while (bvec >= bio->bi_io_vec); + bio_put(bio); + if (atomic_dec_and_test(&super->s_pending_writes)) + wake_up(&wq); +} + +static int __bdev_writeseg(struct super_block *sb, u64 ofs, pgoff_t index, + size_t nr_pages) +{ + struct logfs_super *super = logfs_super(sb); + struct address_space *mapping = super->s_mapping_inode->i_mapping; + struct bio *bio; + struct page *page; + struct request_queue *q = bdev_get_queue(sb->s_bdev); + unsigned int max_pages = queue_max_hw_sectors(q) >> (PAGE_SHIFT - 9); + int i; + + bio = bio_alloc(GFP_NOFS, max_pages); + BUG_ON(!bio); /* FIXME: handle this */ + + for (i = 0; i < nr_pages; i++) { + if (i >= max_pages) { + /* Block layer cannot split bios :( */ + bio->bi_vcnt = i; + bio->bi_idx = 0; + bio->bi_size = i * PAGE_SIZE; + bio->bi_bdev = super->s_bdev; + bio->bi_sector = ofs >> 9; + bio->bi_private = sb; + bio->bi_end_io = writeseg_end_io; + atomic_inc(&super->s_pending_writes); + submit_bio(WRITE, bio); + + ofs += i * PAGE_SIZE; + index += i; + nr_pages -= i; + i = 0; + + bio = bio_alloc(GFP_NOFS, max_pages); + BUG_ON(!bio); + } + page = find_lock_page(mapping, index + i); + BUG_ON(!page); + bio->bi_io_vec[i].bv_page = page; + bio->bi_io_vec[i].bv_len = PAGE_SIZE; + bio->bi_io_vec[i].bv_offset = 0; + + BUG_ON(PageWriteback(page)); + set_page_writeback(page); + unlock_page(page); + } + bio->bi_vcnt = nr_pages; + bio->bi_idx = 0; + bio->bi_size = nr_pages * PAGE_SIZE; + bio->bi_bdev = super->s_bdev; + bio->bi_sector = ofs >> 9; + bio->bi_private = sb; + bio->bi_end_io = writeseg_end_io; + atomic_inc(&super->s_pending_writes); + submit_bio(WRITE, bio); + return 0; +} + +static void bdev_writeseg(struct super_block *sb, u64 ofs, size_t len) +{ + struct logfs_super *super = logfs_super(sb); + int head; + + BUG_ON(super->s_flags & LOGFS_SB_FLAG_RO); + + if (len == 0) { + /* This can happen when the object fit perfectly into a + * segment, the segment gets written per sync and subsequently + * closed. + */ + return; + } + head = ofs & (PAGE_SIZE - 1); + if (head) { + ofs -= head; + len += head; + } + len = PAGE_ALIGN(len); + __bdev_writeseg(sb, ofs, ofs >> PAGE_SHIFT, len >> PAGE_SHIFT); + generic_unplug_device(bdev_get_queue(logfs_super(sb)->s_bdev)); +} + +static int bdev_erase(struct super_block *sb, loff_t to, size_t len) +{ + struct logfs_super *super = logfs_super(sb); + struct address_space *mapping = super->s_mapping_inode->i_mapping; + struct page *page; + pgoff_t index = to >> PAGE_SHIFT; + int i, nr_pages = len >> PAGE_SHIFT; + + BUG_ON(to & (PAGE_SIZE - 1)); + BUG_ON(len & (PAGE_SIZE - 1)); + + if (logfs_super(sb)->s_flags & LOGFS_SB_FLAG_RO) + return -EROFS; + + for (i = 0; i < nr_pages; i++) { + page = find_get_page(mapping, index + i); + if (page) { + memset(page_address(page), 0xFF, PAGE_SIZE); + page_cache_release(page); + } + } + return 0; +} + +static void bdev_sync(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + + wait_event(wq, atomic_read(&super->s_pending_writes) == 0); +} + +static struct page *bdev_find_first_sb(struct super_block *sb, u64 *ofs) +{ + struct logfs_super *super = logfs_super(sb); + struct address_space *mapping = super->s_mapping_inode->i_mapping; + filler_t *filler = bdev_readpage; + + *ofs = 0; + return read_cache_page(mapping, 0, filler, sb); +} + +static struct page *bdev_find_last_sb(struct super_block *sb, u64 *ofs) +{ + struct logfs_super *super = logfs_super(sb); + struct address_space *mapping = super->s_mapping_inode->i_mapping; + filler_t *filler = bdev_readpage; + u64 pos = (super->s_bdev->bd_inode->i_size & ~0xfffULL) - 0x1000; + pgoff_t index = pos >> PAGE_SHIFT; + + *ofs = pos; + return read_cache_page(mapping, index, filler, sb); +} + +static int bdev_write_sb(struct super_block *sb, struct page *page) +{ + struct block_device *bdev = logfs_super(sb)->s_bdev; + + /* Nothing special to do for block devices. */ + return sync_request(page, bdev, WRITE); +} + +static void bdev_put_device(struct super_block *sb) +{ + close_bdev_exclusive(logfs_super(sb)->s_bdev, FMODE_READ|FMODE_WRITE); +} + +static const struct logfs_device_ops bd_devops = { + .find_first_sb = bdev_find_first_sb, + .find_last_sb = bdev_find_last_sb, + .write_sb = bdev_write_sb, + .readpage = bdev_readpage, + .writeseg = bdev_writeseg, + .erase = bdev_erase, + .sync = bdev_sync, + .put_device = bdev_put_device, +}; + +int logfs_get_sb_bdev(struct file_system_type *type, int flags, + const char *devname, struct vfsmount *mnt) +{ + struct block_device *bdev; + + bdev = open_bdev_exclusive(devname, FMODE_READ|FMODE_WRITE, type); + if (IS_ERR(bdev)) + return PTR_ERR(bdev); + + if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) { + int mtdnr = MINOR(bdev->bd_dev); + close_bdev_exclusive(bdev, FMODE_READ|FMODE_WRITE); + return logfs_get_sb_mtd(type, flags, mtdnr, mnt); + } + + return logfs_get_sb_device(type, flags, NULL, bdev, &bd_devops, mnt); +} diff --git a/fs/logfs/dev_mtd.c b/fs/logfs/dev_mtd.c new file mode 100644 index 00000000000..68e99d046c2 --- /dev/null +++ b/fs/logfs/dev_mtd.c @@ -0,0 +1,253 @@ +/* + * fs/logfs/dev_mtd.c - Device access methods for MTD + * + * As should be obvious for Linux kernel code, license is GPLv2 + * + * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org> + */ +#include "logfs.h" +#include <linux/completion.h> +#include <linux/mount.h> +#include <linux/sched.h> + +#define PAGE_OFS(ofs) ((ofs) & (PAGE_SIZE-1)) + +static int mtd_read(struct super_block *sb, loff_t ofs, size_t len, void *buf) +{ + struct mtd_info *mtd = logfs_super(sb)->s_mtd; + size_t retlen; + int ret; + + ret = mtd->read(mtd, ofs, len, &retlen, buf); + BUG_ON(ret == -EINVAL); + if (ret) + return ret; + + /* Not sure if we should loop instead. */ + if (retlen != len) + return -EIO; + + return 0; +} + +static int mtd_write(struct super_block *sb, loff_t ofs, size_t len, void *buf) +{ + struct logfs_super *super = logfs_super(sb); + struct mtd_info *mtd = super->s_mtd; + size_t retlen; + loff_t page_start, page_end; + int ret; + + if (super->s_flags & LOGFS_SB_FLAG_RO) + return -EROFS; + + BUG_ON((ofs >= mtd->size) || (len > mtd->size - ofs)); + BUG_ON(ofs != (ofs >> super->s_writeshift) << super->s_writeshift); + BUG_ON(len > PAGE_CACHE_SIZE); + page_start = ofs & PAGE_CACHE_MASK; + page_end = PAGE_CACHE_ALIGN(ofs + len) - 1; + ret = mtd->write(mtd, ofs, len, &retlen, buf); + if (ret || (retlen != len)) + return -EIO; + + return 0; +} + +/* + * For as long as I can remember (since about 2001) mtd->erase has been an + * asynchronous interface lacking the first driver to actually use the + * asynchronous properties. So just to prevent the first implementor of such + * a thing from breaking logfs in 2350, we do the usual pointless dance to + * declare a completion variable and wait for completion before returning + * from mtd_erase(). What an excercise in futility! + */ +static void logfs_erase_callback(struct erase_info *ei) +{ + complete((struct completion *)ei->priv); +} + +static int mtd_erase_mapping(struct super_block *sb, loff_t ofs, size_t len) +{ + struct logfs_super *super = logfs_super(sb); + struct address_space *mapping = super->s_mapping_inode->i_mapping; + struct page *page; + pgoff_t index = ofs >> PAGE_SHIFT; + + for (index = ofs >> PAGE_SHIFT; index < (ofs + len) >> PAGE_SHIFT; index++) { + page = find_get_page(mapping, index); + if (!page) + continue; + memset(page_address(page), 0xFF, PAGE_SIZE); + page_cache_release(page); + } + return 0; +} + +static int mtd_erase(struct super_block *sb, loff_t ofs, size_t len) +{ + struct mtd_info *mtd = logfs_super(sb)->s_mtd; + struct erase_info ei; + DECLARE_COMPLETION_ONSTACK(complete); + int ret; + + BUG_ON(len % mtd->erasesize); + if (logfs_super(sb)->s_flags & LOGFS_SB_FLAG_RO) + return -EROFS; + + memset(&ei, 0, sizeof(ei)); + ei.mtd = mtd; + ei.addr = ofs; + ei.len = len; + ei.callback = logfs_erase_callback; + ei.priv = (long)&complete; + ret = mtd->erase(mtd, &ei); + if (ret) + return -EIO; + + wait_for_completion(&complete); + if (ei.state != MTD_ERASE_DONE) + return -EIO; + return mtd_erase_mapping(sb, ofs, len); +} + +static void mtd_sync(struct super_block *sb) +{ + struct mtd_info *mtd = logfs_super(sb)->s_mtd; + + if (mtd->sync) + mtd->sync(mtd); +} + +static int mtd_readpage(void *_sb, struct page *page) +{ + struct super_block *sb = _sb; + int err; + + err = mtd_read(sb, page->index << PAGE_SHIFT, PAGE_SIZE, + page_address(page)); + if (err == -EUCLEAN) { + err = 0; + /* FIXME: force GC this segment */ + } + if (err) { + ClearPageUptodate(page); + SetPageError(page); + } else { + SetPageUptodate(page); + ClearPageError(page); + } + unlock_page(page); + return err; +} + +static struct page *mtd_find_first_sb(struct super_block *sb, u64 *ofs) +{ + struct logfs_super *super = logfs_super(sb); + struct address_space *mapping = super->s_mapping_inode->i_mapping; + filler_t *filler = mtd_readpage; + struct mtd_info *mtd = super->s_mtd; + + if (!mtd->block_isbad) + return NULL; + + *ofs = 0; + while (mtd->block_isbad(mtd, *ofs)) { + *ofs += mtd->erasesize; + if (*ofs >= mtd->size) + return NULL; + } + BUG_ON(*ofs & ~PAGE_MASK); + return read_cache_page(mapping, *ofs >> PAGE_SHIFT, filler, sb); +} + +static struct page *mtd_find_last_sb(struct super_block *sb, u64 *ofs) +{ + struct logfs_super *super = logfs_super(sb); + struct address_space *mapping = super->s_mapping_inode->i_mapping; + filler_t *filler = mtd_readpage; + struct mtd_info *mtd = super->s_mtd; + + if (!mtd->block_isbad) + return NULL; + + *ofs = mtd->size - mtd->erasesize; + while (mtd->block_isbad(mtd, *ofs)) { + *ofs -= mtd->erasesize; + if (*ofs <= 0) + return NULL; + } + *ofs = *ofs + mtd->erasesize - 0x1000; + BUG_ON(*ofs & ~PAGE_MASK); + return read_cache_page(mapping, *ofs >> PAGE_SHIFT, filler, sb); +} + +static int __mtd_writeseg(struct super_block *sb, u64 ofs, pgoff_t index, + size_t nr_pages) +{ + struct logfs_super *super = logfs_super(sb); + struct address_space *mapping = super->s_mapping_inode->i_mapping; + struct page *page; + int i, err; + + for (i = 0; i < nr_pages; i++) { + page = find_lock_page(mapping, index + i); + BUG_ON(!page); + + err = mtd_write(sb, page->index << PAGE_SHIFT, PAGE_SIZE, + page_address(page)); + unlock_page(page); + page_cache_release(page); + if (err) + return err; + } + return 0; +} + +static void mtd_writeseg(struct super_block *sb, u64 ofs, size_t len) +{ + struct logfs_super *super = logfs_super(sb); + int head; + + if (super->s_flags & LOGFS_SB_FLAG_RO) + return; + + if (len == 0) { + /* This can happen when the object fit perfectly into a + * segment, the segment gets written per sync and subsequently + * closed. + */ + return; + } + head = ofs & (PAGE_SIZE - 1); + if (head) { + ofs -= head; + len += head; + } + len = PAGE_ALIGN(len); + __mtd_writeseg(sb, ofs, ofs >> PAGE_SHIFT, len >> PAGE_SHIFT); +} + +static void mtd_put_device(struct super_block *sb) +{ + put_mtd_device(logfs_super(sb)->s_mtd); +} + +static const struct logfs_device_ops mtd_devops = { + .find_first_sb = mtd_find_first_sb, + .find_last_sb = mtd_find_last_sb, + .readpage = mtd_readpage, + .writeseg = mtd_writeseg, + .erase = mtd_erase, + .sync = mtd_sync, + .put_device = mtd_put_device, +}; + +int logfs_get_sb_mtd(struct file_system_type *type, int flags, + int mtdnr, struct vfsmount *mnt) +{ + struct mtd_info *mtd; + const struct logfs_device_ops *devops = &mtd_devops; + + mtd = get_mtd_device(NULL, mtdnr); + return logfs_get_sb_device(type, flags, mtd, NULL, devops, mnt); +} diff --git a/fs/logfs/dir.c b/fs/logfs/dir.c new file mode 100644 index 00000000000..89104e6f81c --- /dev/null +++ b/fs/logfs/dir.c @@ -0,0 +1,818 @@ +/* + * fs/logfs/dir.c - directory-related code + * + * As should be obvious for Linux kernel code, license is GPLv2 + * + * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org> + */ +#include "logfs.h" + + +/* + * Atomic dir operations + * + * Directory operations are by default not atomic. Dentries and Inodes are + * created/removed/altered in seperate operations. Therefore we need to do + * a small amount of journaling. + * + * Create, link, mkdir, mknod and symlink all share the same function to do + * the work: __logfs_create. This function works in two atomic steps: + * 1. allocate inode (remember in journal) + * 2. allocate dentry (clear journal) + * + * As we can only get interrupted between the two, when the inode we just + * created is simply stored in the anchor. On next mount, if we were + * interrupted, we delete the inode. From a users point of view the + * operation never happened. + * + * Unlink and rmdir also share the same function: unlink. Again, this + * function works in two atomic steps + * 1. remove dentry (remember inode in journal) + * 2. unlink inode (clear journal) + * + * And again, on the next mount, if we were interrupted, we delete the inode. + * From a users point of view the operation succeeded. + * + * Rename is the real pain to deal with, harder than all the other methods + * combined. Depending on the circumstances we can run into three cases. + * A "target rename" where the target dentry already existed, a "local + * rename" where both parent directories are identical or a "cross-directory + * rename" in the remaining case. + * + * Local rename is atomic, as the old dentry is simply rewritten with a new + * name. + * + * Cross-directory rename works in two steps, similar to __logfs_create and + * logfs_unlink: + * 1. Write new dentry (remember old dentry in journal) + * 2. Remove old dentry (clear journal) + * + * Here we remember a dentry instead of an inode. On next mount, if we were + * interrupted, we delete the dentry. From a users point of view, the + * operation succeeded. + * + * Target rename works in three atomic steps: + * 1. Attach old inode to new dentry (remember old dentry and new inode) + * 2. Remove old dentry (still remember the new inode) + * 3. Remove victim inode + * + * Here we remember both an inode an a dentry. If we get interrupted + * between steps 1 and 2, we delete both the dentry and the inode. If + * we get interrupted between steps 2 and 3, we delete just the inode. + * In either case, the remaining objects are deleted on next mount. From + * a users point of view, the operation succeeded. + */ + +static int write_dir(struct inode *dir, struct logfs_disk_dentry *dd, + loff_t pos) +{ + return logfs_inode_write(dir, dd, sizeof(*dd), pos, WF_LOCK, NULL); +} + +static int write_inode(struct inode *inode) +{ + return __logfs_write_inode(inode, WF_LOCK); +} + +static s64 dir_seek_data(struct inode *inode, s64 pos) +{ + s64 new_pos = logfs_seek_data(inode, pos); + + return max(pos, new_pos - 1); +} + +static int beyond_eof(struct inode *inode, loff_t bix) +{ + loff_t pos = bix << inode->i_sb->s_blocksize_bits; + return pos >= i_size_read(inode); +} + +/* + * Prime value was chosen to be roughly 256 + 26. r5 hash uses 11, + * so short names (len <= 9) don't even occupy the complete 32bit name + * space. A prime >256 ensures short names quickly spread the 32bit + * name space. Add about 26 for the estimated amount of information + * of each character and pick a prime nearby, preferrably a bit-sparse + * one. + */ +static u32 hash_32(const char *s, int len, u32 seed) +{ + u32 hash = seed; + int i; + + for (i = 0; i < len; i++) + hash = hash * 293 + s[i]; + return hash; +} + +/* + * We have to satisfy several conflicting requirements here. Small + * directories should stay fairly compact and not require too many + * indirect blocks. The number of possible locations for a given hash + * should be small to make lookup() fast. And we should try hard not + * to overflow the 32bit name space or nfs and 32bit host systems will + * be unhappy. + * + * So we use the following scheme. First we reduce the hash to 0..15 + * and try a direct block. If that is occupied we reduce the hash to + * 16..255 and try an indirect block. Same for 2x and 3x indirect + * blocks. Lastly we reduce the hash to 0x800_0000 .. 0xffff_ffff, + * but use buckets containing eight entries instead of a single one. + * + * Using 16 entries should allow for a reasonable amount of hash + * collisions, so the 32bit name space can be packed fairly tight + * before overflowing. Oh and currently we don't overflow but return + * and error. + * + * How likely are collisions? Doing the appropriate math is beyond me + * and the Bronstein textbook. But running a test program to brute + * force collisions for a couple of days showed that on average the + * first collision occurs after 598M entries, with 290M being the + * smallest result. Obviously 21 entries could already cause a + * collision if all entries are carefully chosen. + */ +static pgoff_t hash_index(u32 hash, int round) +{ + switch (round) { + case 0: + return hash % I0_BLOCKS; + case 1: + return I0_BLOCKS + hash % (I1_BLOCKS - I0_BLOCKS); + case 2: + return I1_BLOCKS + hash % (I2_BLOCKS - I1_BLOCKS); + case 3: + return I2_BLOCKS + hash % (I3_BLOCKS - I2_BLOCKS); + case 4 ... 19: + return I3_BLOCKS + 16 * (hash % (((1<<31) - I3_BLOCKS) / 16)) + + round - 4; + } + BUG(); +} + +static struct page *logfs_get_dd_page(struct inode *dir, struct dentry *dentry) +{ + struct qstr *name = &dentry->d_name; + struct page *page; + struct logfs_disk_dentry *dd; + u32 hash = hash_32(name->name, name->len, 0); + pgoff_t index; + int round; + + if (name->len > LOGFS_MAX_NAMELEN) + return ERR_PTR(-ENAMETOOLONG); + + for (round = 0; round < 20; round++) { + index = hash_index(hash, round); + + if (beyond_eof(dir, index)) + return NULL; + if (!logfs_exist_block(dir, index)) + continue; + page = read_cache_page(dir->i_mapping, index, + (filler_t *)logfs_readpage, NULL); + if (IS_ERR(page)) + return page; + dd = kmap_atomic(page, KM_USER0); + BUG_ON(dd->namelen == 0); + + if (name->len != be16_to_cpu(dd->namelen) || + memcmp(name->name, dd->name, name->len)) { + kunmap_atomic(dd, KM_USER0); + page_cache_release(page); + continue; + } + + kunmap_atomic(dd, KM_USER0); + return page; + } + return NULL; +} + +static int logfs_remove_inode(struct inode *inode) +{ + int ret; + + inode->i_nlink--; + ret = write_inode(inode); + LOGFS_BUG_ON(ret, inode->i_sb); + return ret; +} + +static void abort_transaction(struct inode *inode, struct logfs_transaction *ta) +{ + if (logfs_inode(inode)->li_block) + logfs_inode(inode)->li_block->ta = NULL; + kfree(ta); +} + +static int logfs_unlink(struct inode *dir, struct dentry *dentry) +{ + struct logfs_super *super = logfs_super(dir->i_sb); + struct inode *inode = dentry->d_inode; + struct logfs_transaction *ta; + struct page *page; + pgoff_t index; + int ret; + + ta = kzalloc(sizeof(*ta), GFP_KERNEL); + if (!ta) + return -ENOMEM; + + ta->state = UNLINK_1; + ta->ino = inode->i_ino; + + inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; + + page = logfs_get_dd_page(dir, dentry); + if (!page) + return -ENOENT; + if (IS_ERR(page)) + return PTR_ERR(page); + index = page->index; + page_cache_release(page); + + mutex_lock(&super->s_dirop_mutex); + logfs_add_transaction(dir, ta); + + ret = logfs_delete(dir, index, NULL); + if (!ret) + ret = write_inode(dir); + + if (ret) { + abort_transaction(dir, ta); + printk(KERN_ERR"LOGFS: unable to delete inode\n"); + goto out; + } + + ta->state = UNLINK_2; + logfs_add_transaction(inode, ta); + ret = logfs_remove_inode(inode); +out: + mutex_unlock(&super->s_dirop_mutex); + return ret; +} + +static inline int logfs_empty_dir(struct inode *dir) +{ + u64 data; + + data = logfs_seek_data(dir, 0) << dir->i_sb->s_blocksize_bits; + return data >= i_size_read(dir); +} + +static int logfs_rmdir(struct inode *dir, struct dentry *dentry) +{ + struct inode *inode = dentry->d_inode; + + if (!logfs_empty_dir(inode)) + return -ENOTEMPTY; + + return logfs_unlink(dir, dentry); +} + +/* FIXME: readdir currently has it's own dir_walk code. I don't see a good + * way to combine the two copies */ +#define IMPLICIT_NODES 2 +static int __logfs_readdir(struct file *file, void *buf, filldir_t filldir) +{ + struct inode *dir = file->f_dentry->d_inode; + loff_t pos = file->f_pos - IMPLICIT_NODES; + struct page *page; + struct logfs_disk_dentry *dd; + int full; + + BUG_ON(pos < 0); + for (;; pos++) { + if (beyond_eof(dir, pos)) + break; + if (!logfs_exist_block(dir, pos)) { + /* deleted dentry */ + pos = dir_seek_data(dir, pos); + continue; + } + page = read_cache_page(dir->i_mapping, pos, + (filler_t *)logfs_readpage, NULL); + if (IS_ERR(page)) + return PTR_ERR(page); + dd = kmap_atomic(page, KM_USER0); + BUG_ON(dd->namelen == 0); + + full = filldir(buf, (char *)dd->name, be16_to_cpu(dd->namelen), + pos, be64_to_cpu(dd->ino), dd->type); + kunmap_atomic(dd, KM_USER0); + page_cache_release(page); + if (full) + break; + } + + file->f_pos = pos + IMPLICIT_NODES; + return 0; +} + +static int logfs_readdir(struct file *file, void *buf, filldir_t filldir) +{ + struct inode *inode = file->f_dentry->d_inode; + ino_t pino = parent_ino(file->f_dentry); + int err; + + if (file->f_pos < 0) + return -EINVAL; + + if (file->f_pos == 0) { + if (filldir(buf, ".", 1, 1, inode->i_ino, DT_DIR) < 0) + return 0; + file->f_pos++; + } + if (file->f_pos == 1) { + if (filldir(buf, "..", 2, 2, pino, DT_DIR) < 0) + return 0; + file->f_pos++; + } + + err = __logfs_readdir(file, buf, filldir); + return err; +} + +static void logfs_set_name(struct logfs_disk_dentry *dd, struct qstr *name) +{ + dd->namelen = cpu_to_be16(name->len); + memcpy(dd->name, name->name, name->len); +} + +static struct dentry *logfs_lookup(struct inode *dir, struct dentry *dentry, + struct nameidata *nd) +{ + struct page *page; + struct logfs_disk_dentry *dd; + pgoff_t index; + u64 ino = 0; + struct inode *inode; + + page = logfs_get_dd_page(dir, dentry); + if (IS_ERR(page)) + return ERR_CAST(page); + if (!page) { + d_add(dentry, NULL); + return NULL; + } + index = page->index; + dd = kmap_atomic(page, KM_USER0); + ino = be64_to_cpu(dd->ino); + kunmap_atomic(dd, KM_USER0); + page_cache_release(page); + + inode = logfs_iget(dir->i_sb, ino); + if (IS_ERR(inode)) { + printk(KERN_ERR"LogFS: Cannot read inode #%llx for dentry (%lx, %lx)n", + ino, dir->i_ino, index); + return ERR_CAST(inode); + } + return d_splice_alias(inode, dentry); +} + +static void grow_dir(struct inode *dir, loff_t index) +{ + index = (index + 1) << dir->i_sb->s_blocksize_bits; + if (i_size_read(dir) < index) + i_size_write(dir, index); +} + +static int logfs_write_dir(struct inode *dir, struct dentry *dentry, + struct inode *inode) +{ + struct page *page; + struct logfs_disk_dentry *dd; + u32 hash = hash_32(dentry->d_name.name, dentry->d_name.len, 0); + pgoff_t index; + int round, err; + + for (round = 0; round < 20; round++) { + index = hash_index(hash, round); + + if (logfs_exist_block(dir, index)) + continue; + page = find_or_create_page(dir->i_mapping, index, GFP_KERNEL); + if (!page) + return -ENOMEM; + + dd = kmap_atomic(page, KM_USER0); + memset(dd, 0, sizeof(*dd)); + dd->ino = cpu_to_be64(inode->i_ino); + dd->type = logfs_type(inode); + logfs_set_name(dd, &dentry->d_name); + kunmap_atomic(dd, KM_USER0); + + err = logfs_write_buf(dir, page, WF_LOCK); + unlock_page(page); + page_cache_release(page); + if (!err) + grow_dir(dir, index); + return err; + } + /* FIXME: Is there a better return value? In most cases neither + * the filesystem nor the directory are full. But we have had + * too many collisions for this particular hash and no fallback. + */ + return -ENOSPC; +} + +static int __logfs_create(struct inode *dir, struct dentry *dentry, + struct inode *inode, const char *dest, long destlen) +{ + struct logfs_super *super = logfs_super(dir->i_sb); + struct logfs_inode *li = logfs_inode(inode); + struct logfs_transaction *ta; + int ret; + + ta = kzalloc(sizeof(*ta), GFP_KERNEL); + if (!ta) + return -ENOMEM; + + ta->state = CREATE_1; + ta->ino = inode->i_ino; + mutex_lock(&super->s_dirop_mutex); + logfs_add_transaction(inode, ta); + + if (dest) { + /* symlink */ + ret = logfs_inode_write(inode, dest, destlen, 0, WF_LOCK, NULL); + if (!ret) + ret = write_inode(inode); + } else { + /* creat/mkdir/mknod */ + ret = write_inode(inode); + } + if (ret) { + abort_transaction(inode, ta); + li->li_flags |= LOGFS_IF_STILLBORN; + /* FIXME: truncate symlink */ + inode->i_nlink--; + iput(inode); + goto out; + } + + ta->state = CREATE_2; + logfs_add_transaction(dir, ta); + ret = logfs_write_dir(dir, dentry, inode); + /* sync directory */ + if (!ret) + ret = write_inode(dir); + + if (ret) { + logfs_del_transaction(dir, ta); + ta->state = CREATE_2; + logfs_add_transaction(inode, ta); + logfs_remove_inode(inode); + iput(inode); + goto out; + } + d_instantiate(dentry, inode); +out: + mutex_unlock(&super->s_dirop_mutex); + return ret; +} + +static int logfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) +{ + struct inode *inode; + + /* + * FIXME: why do we have to fill in S_IFDIR, while the mode is + * correct for mknod, creat, etc.? Smells like the vfs *should* + * do it for us but for some reason fails to do so. + */ + inode = logfs_new_inode(dir, S_IFDIR | mode); + if (IS_ERR(inode)) + return PTR_ERR(inode); + + inode->i_op = &logfs_dir_iops; + inode->i_fop = &logfs_dir_fops; + + return __logfs_create(dir, dentry, inode, NULL, 0); +} + +static int logfs_create(struct inode *dir, struct dentry *dentry, int mode, + struct nameidata *nd) +{ + struct inode *inode; + + inode = logfs_new_inode(dir, mode); + if (IS_ERR(inode)) + return PTR_ERR(inode); + + inode->i_op = &logfs_reg_iops; + inode->i_fop = &logfs_reg_fops; + inode->i_mapping->a_ops = &logfs_reg_aops; + + return __logfs_create(dir, dentry, inode, NULL, 0); +} + +static int logfs_mknod(struct inode *dir, struct dentry *dentry, int mode, + dev_t rdev) +{ + struct inode *inode; + + if (dentry->d_name.len > LOGFS_MAX_NAMELEN) + return -ENAMETOOLONG; + + inode = logfs_new_inode(dir, mode); + if (IS_ERR(inode)) + return PTR_ERR(inode); + + init_special_inode(inode, mode, rdev); + + return __logfs_create(dir, dentry, inode, NULL, 0); +} + +static int logfs_symlink(struct inode *dir, struct dentry *dentry, + const char *target) +{ + struct inode *inode; + size_t destlen = strlen(target) + 1; + + if (destlen > dir->i_sb->s_blocksize) + return -ENAMETOOLONG; + + inode = logfs_new_inode(dir, S_IFLNK | 0777); + if (IS_ERR(inode)) + return PTR_ERR(inode); + + inode->i_op = &logfs_symlink_iops; + inode->i_mapping->a_ops = &logfs_reg_aops; + + return __logfs_create(dir, dentry, inode, target, destlen); +} + +static int logfs_permission(struct inode *inode, int mask) +{ + return generic_permission(inode, mask, NULL); +} + +static int logfs_link(struct dentry *old_dentry, struct inode *dir, + struct dentry *dentry) +{ + struct inode *inode = old_dentry->d_inode; + + if (inode->i_nlink >= LOGFS_LINK_MAX) + return -EMLINK; + + inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; + atomic_inc(&inode->i_count); + inode->i_nlink++; + mark_inode_dirty_sync(inode); + + return __logfs_create(dir, dentry, inode, NULL, 0); +} + +static int logfs_get_dd(struct inode *dir, struct dentry *dentry, + struct logfs_disk_dentry *dd, loff_t *pos) +{ + struct page *page; + void *map; + + page = logfs_get_dd_page(dir, dentry); + if (IS_ERR(page)) + return PTR_ERR(page); + *pos = page->index; + map = kmap_atomic(page, KM_USER0); + memcpy(dd, map, sizeof(*dd)); + kunmap_atomic(map, KM_USER0); + page_cache_release(page); + return 0; +} + +static int logfs_delete_dd(struct inode *dir, loff_t pos) +{ + /* + * Getting called with pos somewhere beyond eof is either a goofup + * within this file or means someone maliciously edited the + * (crc-protected) journal. + */ + BUG_ON(beyond_eof(dir, pos)); + dir->i_ctime = dir->i_mtime = CURRENT_TIME; + log_dir(" Delete dentry (%lx, %llx)\n", dir->i_ino, pos); + return logfs_delete(dir, pos, NULL); +} + +/* + * Cross-directory rename, target does not exist. Just a little nasty. + * Create a new dentry in the target dir, then remove the old dentry, + * all the while taking care to remember our operation in the journal. + */ +static int logfs_rename_cross(struct inode *old_dir, struct dentry *old_dentry, + struct inode *new_dir, struct dentry *new_dentry) +{ + struct logfs_super *super = logfs_super(old_dir->i_sb); + struct logfs_disk_dentry dd; + struct logfs_transaction *ta; + loff_t pos; + int err; + + /* 1. locate source dd */ + err = logfs_get_dd(old_dir, old_dentry, &dd, &pos); + if (err) + return err; + + ta = kzalloc(sizeof(*ta), GFP_KERNEL); + if (!ta) + return -ENOMEM; + + ta->state = CROSS_RENAME_1; + ta->dir = old_dir->i_ino; + ta->pos = pos; + + /* 2. write target dd */ + mutex_lock(&super->s_dirop_mutex); + logfs_add_transaction(new_dir, ta); + err = logfs_write_dir(new_dir, new_dentry, old_dentry->d_inode); + if (!err) + err = write_inode(new_dir); + + if (err) { + super->s_rename_dir = 0; + super->s_rename_pos = 0; + abort_transaction(new_dir, ta); + goto out; + } + + /* 3. remove source dd */ + ta->state = CROSS_RENAME_2; + logfs_add_transaction(old_dir, ta); + err = logfs_delete_dd(old_dir, pos); + if (!err) + err = write_inode(old_dir); + LOGFS_BUG_ON(err, old_dir->i_sb); +out: + mutex_unlock(&super->s_dirop_mutex); + return err; +} + +static int logfs_replace_inode(struct inode *dir, struct dentry *dentry, + struct logfs_disk_dentry *dd, struct inode *inode) +{ + loff_t pos; + int err; + + err = logfs_get_dd(dir, dentry, dd, &pos); + if (err) + return err; + dd->ino = cpu_to_be64(inode->i_ino); + dd->type = logfs_type(inode); + + err = write_dir(dir, dd, pos); + if (err) + return err; + log_dir("Replace dentry (%lx, %llx) %s -> %llx\n", dir->i_ino, pos, + dd->name, be64_to_cpu(dd->ino)); + return write_inode(dir); +} + +/* Target dentry exists - the worst case. We need to attach the source + * inode to the target dentry, then remove the orphaned target inode and + * source dentry. + */ +static int logfs_rename_target(struct inode *old_dir, struct dentry *old_dentry, + struct inode *new_dir, struct dentry *new_dentry) +{ + struct logfs_super *super = logfs_super(old_dir->i_sb); + struct inode *old_inode = old_dentry->d_inode; + struct inode *new_inode = new_dentry->d_inode; + int isdir = S_ISDIR(old_inode->i_mode); + struct logfs_disk_dentry dd; + struct logfs_transaction *ta; + loff_t pos; + int err; + + BUG_ON(isdir != S_ISDIR(new_inode->i_mode)); + if (isdir) { + if (!logfs_empty_dir(new_inode)) + return -ENOTEMPTY; + } + + /* 1. locate source dd */ + err = logfs_get_dd(old_dir, old_dentry, &dd, &pos); + if (err) + return err; + + ta = kzalloc(sizeof(*ta), GFP_KERNEL); + if (!ta) + return -ENOMEM; + + ta->state = TARGET_RENAME_1; + ta->dir = old_dir->i_ino; + ta->pos = pos; + ta->ino = new_inode->i_ino; + + /* 2. attach source inode to target dd */ + mutex_lock(&super->s_dirop_mutex); + logfs_add_transaction(new_dir, ta); + err = logfs_replace_inode(new_dir, new_dentry, &dd, old_inode); + if (err) { + super->s_rename_dir = 0; + super->s_rename_pos = 0; + super->s_victim_ino = 0; + abort_transaction(new_dir, ta); + goto out; + } + + /* 3. remove source dd */ + ta->state = TARGET_RENAME_2; + logfs_add_transaction(old_dir, ta); + err = logfs_delete_dd(old_dir, pos); + if (!err) + err = write_inode(old_dir); + LOGFS_BUG_ON(err, old_dir->i_sb); + + /* 4. remove target inode */ + ta->state = TARGET_RENAME_3; + logfs_add_transaction(new_inode, ta); + err = logfs_remove_inode(new_inode); + +out: + mutex_unlock(&super->s_dirop_mutex); + return err; +} + +static int logfs_rename(struct inode *old_dir, struct dentry *old_dentry, + struct inode *new_dir, struct dentry *new_dentry) +{ + if (new_dentry->d_inode) + return logfs_rename_target(old_dir, old_dentry, + new_dir, new_dentry); + return logfs_rename_cross(old_dir, old_dentry, new_dir, new_dentry); +} + +/* No locking done here, as this is called before .get_sb() returns. */ +int logfs_replay_journal(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + struct inode *inode; + u64 ino, pos; + int err; + + if (super->s_victim_ino) { + /* delete victim inode */ + ino = super->s_victim_ino; + printk(KERN_INFO"LogFS: delete unmapped inode #%llx\n", ino); + inode = logfs_iget(sb, ino); + if (IS_ERR(inode)) + goto fail; + + LOGFS_BUG_ON(i_size_read(inode) > 0, sb); + super->s_victim_ino = 0; + err = logfs_remove_inode(inode); + iput(inode); + if (err) { + super->s_victim_ino = ino; + goto fail; + } + } + if (super->s_rename_dir) { + /* delete old dd from rename */ + ino = super->s_rename_dir; + pos = super->s_rename_pos; + printk(KERN_INFO"LogFS: delete unbacked dentry (%llx, %llx)\n", + ino, pos); + inode = logfs_iget(sb, ino); + if (IS_ERR(inode)) + goto fail; + + super->s_rename_dir = 0; + super->s_rename_pos = 0; + err = logfs_delete_dd(inode, pos); + iput(inode); + if (err) { + super->s_rename_dir = ino; + super->s_rename_pos = pos; + goto fail; + } + } + return 0; +fail: + LOGFS_BUG(sb); + return -EIO; +} + +const struct inode_operations logfs_symlink_iops = { + .readlink = generic_readlink, + .follow_link = page_follow_link_light, +}; + +const struct inode_operations logfs_dir_iops = { + .create = logfs_create, + .link = logfs_link, + .lookup = logfs_lookup, + .mkdir = logfs_mkdir, + .mknod = logfs_mknod, + .rename = logfs_rename, + .rmdir = logfs_rmdir, + .permission = logfs_permission, + .symlink = logfs_symlink, + .unlink = logfs_unlink, +}; +const struct file_operations logfs_dir_fops = { + .fsync = logfs_fsync, + .ioctl = logfs_ioctl, + .readdir = logfs_readdir, + .read = generic_read_dir, +}; diff --git a/fs/logfs/file.c b/fs/logfs/file.c new file mode 100644 index 00000000000..370f367a933 --- /dev/null +++ b/fs/logfs/file.c @@ -0,0 +1,263 @@ +/* + * fs/logfs/file.c - prepare_write, commit_write and friends + * + * As should be obvious for Linux kernel code, license is GPLv2 + * + * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org> + */ +#include "logfs.h" +#include <linux/sched.h> +#include <linux/writeback.h> + +static int logfs_write_begin(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned flags, + struct page **pagep, void **fsdata) +{ + struct inode *inode = mapping->host; + struct page *page; + pgoff_t index = pos >> PAGE_CACHE_SHIFT; + + page = grab_cache_page_write_begin(mapping, index, flags); + if (!page) + return -ENOMEM; + *pagep = page; + + if ((len == PAGE_CACHE_SIZE) || PageUptodate(page)) + return 0; + if ((pos & PAGE_CACHE_MASK) >= i_size_read(inode)) { + unsigned start = pos & (PAGE_CACHE_SIZE - 1); + unsigned end = start + len; + + /* Reading beyond i_size is simple: memset to zero */ + zero_user_segments(page, 0, start, end, PAGE_CACHE_SIZE); + return 0; + } + return logfs_readpage_nolock(page); +} + +static int logfs_write_end(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned copied, struct page *page, + void *fsdata) +{ + struct inode *inode = mapping->host; + pgoff_t index = page->index; + unsigned start = pos & (PAGE_CACHE_SIZE - 1); + unsigned end = start + copied; + int ret = 0; + + BUG_ON(PAGE_CACHE_SIZE != inode->i_sb->s_blocksize); + BUG_ON(page->index > I3_BLOCKS); + + if (copied < len) { + /* + * Short write of a non-initialized paged. Just tell userspace + * to retry the entire page. + */ + if (!PageUptodate(page)) { + copied = 0; + goto out; + } + } + if (copied == 0) + goto out; /* FIXME: do we need to update inode? */ + + if (i_size_read(inode) < (index << PAGE_CACHE_SHIFT) + end) { + i_size_write(inode, (index << PAGE_CACHE_SHIFT) + end); + mark_inode_dirty_sync(inode); + } + + SetPageUptodate(page); + if (!PageDirty(page)) { + if (!get_page_reserve(inode, page)) + __set_page_dirty_nobuffers(page); + else + ret = logfs_write_buf(inode, page, WF_LOCK); + } +out: + unlock_page(page); + page_cache_release(page); + return ret ? ret : copied; +} + +int logfs_readpage(struct file *file, struct page *page) +{ + int ret; + + ret = logfs_readpage_nolock(page); + unlock_page(page); + return ret; +} + +/* Clear the page's dirty flag in the radix tree. */ +/* TODO: mucking with PageWriteback is silly. Add a generic function to clear + * the dirty bit from the radix tree for filesystems that don't have to wait + * for page writeback to finish (i.e. any compressing filesystem). + */ +static void clear_radix_tree_dirty(struct page *page) +{ + BUG_ON(PagePrivate(page) || page->private); + set_page_writeback(page); + end_page_writeback(page); +} + +static int __logfs_writepage(struct page *page) +{ + struct inode *inode = page->mapping->host; + int err; + + err = logfs_write_buf(inode, page, WF_LOCK); + if (err) + set_page_dirty(page); + else + clear_radix_tree_dirty(page); + unlock_page(page); + return err; +} + +static int logfs_writepage(struct page *page, struct writeback_control *wbc) +{ + struct inode *inode = page->mapping->host; + loff_t i_size = i_size_read(inode); + pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT; + unsigned offset; + u64 bix; + level_t level; + + log_file("logfs_writepage(%lx, %lx, %p)\n", inode->i_ino, page->index, + page); + + logfs_unpack_index(page->index, &bix, &level); + + /* Indirect blocks are never truncated */ + if (level != 0) + return __logfs_writepage(page); + + /* + * TODO: everything below is a near-verbatim copy of nobh_writepage(). + * The relevant bits should be factored out after logfs is merged. + */ + + /* Is the page fully inside i_size? */ + if (bix < end_index) + return __logfs_writepage(page); + + /* Is the page fully outside i_size? (truncate in progress) */ + offset = i_size & (PAGE_CACHE_SIZE-1); + if (bix > end_index || offset == 0) { + unlock_page(page); + return 0; /* don't care */ + } + + /* + * The page straddles i_size. It must be zeroed out on each and every + * writepage invokation because it may be mmapped. "A file is mapped + * in multiples of the page size. For a file that is not a multiple of + * the page size, the remaining memory is zeroed when mapped, and + * writes to that region are not written out to the file." + */ + zero_user_segment(page, offset, PAGE_CACHE_SIZE); + return __logfs_writepage(page); +} + +static void logfs_invalidatepage(struct page *page, unsigned long offset) +{ + move_page_to_btree(page); + BUG_ON(PagePrivate(page) || page->private); +} + +static int logfs_releasepage(struct page *page, gfp_t only_xfs_uses_this) +{ + return 0; /* None of these are easy to release */ +} + + +int logfs_ioctl(struct inode *inode, struct file *file, unsigned int cmd, + unsigned long arg) +{ + struct logfs_inode *li = logfs_inode(inode); + unsigned int oldflags, flags; + int err; + + switch (cmd) { + case FS_IOC_GETFLAGS: + flags = li->li_flags & LOGFS_FL_USER_VISIBLE; + return put_user(flags, (int __user *)arg); + case FS_IOC_SETFLAGS: + if (IS_RDONLY(inode)) + return -EROFS; + + if (!is_owner_or_cap(inode)) + return -EACCES; + + err = get_user(flags, (int __user *)arg); + if (err) + return err; + + mutex_lock(&inode->i_mutex); + oldflags = li->li_flags; + flags &= LOGFS_FL_USER_MODIFIABLE; + flags |= oldflags & ~LOGFS_FL_USER_MODIFIABLE; + li->li_flags = flags; + mutex_unlock(&inode->i_mutex); + + inode->i_ctime = CURRENT_TIME; + mark_inode_dirty_sync(inode); + return 0; + + default: + return -ENOTTY; + } +} + +int logfs_fsync(struct file *file, struct dentry *dentry, int datasync) +{ + struct super_block *sb = dentry->d_inode->i_sb; + struct logfs_super *super = logfs_super(sb); + + /* FIXME: write anchor */ + super->s_devops->sync(sb); + return 0; +} + +static int logfs_setattr(struct dentry *dentry, struct iattr *attr) +{ + struct inode *inode = dentry->d_inode; + int err = 0; + + if (attr->ia_valid & ATTR_SIZE) + err = logfs_truncate(inode, attr->ia_size); + attr->ia_valid &= ~ATTR_SIZE; + + if (!err) + err = inode_change_ok(inode, attr); + if (!err) + err = inode_setattr(inode, attr); + return err; +} + +const struct inode_operations logfs_reg_iops = { + .setattr = logfs_setattr, +}; + +const struct file_operations logfs_reg_fops = { + .aio_read = generic_file_aio_read, + .aio_write = generic_file_aio_write, + .fsync = logfs_fsync, + .ioctl = logfs_ioctl, + .llseek = generic_file_llseek, + .mmap = generic_file_readonly_mmap, + .open = generic_file_open, + .read = do_sync_read, + .write = do_sync_write, +}; + +const struct address_space_operations logfs_reg_aops = { + .invalidatepage = logfs_invalidatepage, + .readpage = logfs_readpage, + .releasepage = logfs_releasepage, + .set_page_dirty = __set_page_dirty_nobuffers, + .writepage = logfs_writepage, + .writepages = generic_writepages, + .write_begin = logfs_write_begin, + .write_end = logfs_write_end, +}; diff --git a/fs/logfs/gc.c b/fs/logfs/gc.c new file mode 100644 index 00000000000..b3656c44190 --- /dev/null +++ b/fs/logfs/gc.c @@ -0,0 +1,730 @@ +/* + * fs/logfs/gc.c - garbage collection code + * + * As should be obvious for Linux kernel code, license is GPLv2 + * + * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org> + */ +#include "logfs.h" +#include <linux/sched.h> + +/* + * Wear leveling needs to kick in when the difference between low erase + * counts and high erase counts gets too big. A good value for "too big" + * may be somewhat below 10% of maximum erase count for the device. + * Why not 397, to pick a nice round number with no specific meaning? :) + * + * WL_RATELIMIT is the minimum time between two wear level events. A huge + * number of segments may fulfil the requirements for wear leveling at the + * same time. If that happens we don't want to cause a latency from hell, + * but just gently pick one segment every so often and minimize overhead. + */ +#define WL_DELTA 397 +#define WL_RATELIMIT 100 +#define MAX_OBJ_ALIASES 2600 +#define SCAN_RATIO 512 /* number of scanned segments per gc'd segment */ +#define LIST_SIZE 64 /* base size of candidate lists */ +#define SCAN_ROUNDS 128 /* maximum number of complete medium scans */ +#define SCAN_ROUNDS_HIGH 4 /* maximum number of higher-level scans */ + +static int no_free_segments(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + + return super->s_free_list.count; +} + +/* journal has distance -1, top-most ifile layer distance 0 */ +static u8 root_distance(struct super_block *sb, gc_level_t __gc_level) +{ + struct logfs_super *super = logfs_super(sb); + u8 gc_level = (__force u8)__gc_level; + + switch (gc_level) { + case 0: /* fall through */ + case 1: /* fall through */ + case 2: /* fall through */ + case 3: + /* file data or indirect blocks */ + return super->s_ifile_levels + super->s_iblock_levels - gc_level; + case 6: /* fall through */ + case 7: /* fall through */ + case 8: /* fall through */ + case 9: + /* inode file data or indirect blocks */ + return super->s_ifile_levels - (gc_level - 6); + default: + printk(KERN_ERR"LOGFS: segment of unknown level %x found\n", + gc_level); + WARN_ON(1); + return super->s_ifile_levels + super->s_iblock_levels; + } +} + +static int segment_is_reserved(struct super_block *sb, u32 segno) +{ + struct logfs_super *super = logfs_super(sb); + struct logfs_area *area; + void *reserved; + int i; + + /* Some segments are reserved. Just pretend they were all valid */ + reserved = btree_lookup32(&super->s_reserved_segments, segno); + if (reserved) + return 1; + + /* Currently open segments */ + for_each_area(i) { + area = super->s_area[i]; + if (area->a_is_open && area->a_segno == segno) + return 1; + } + + return 0; +} + +static void logfs_mark_segment_bad(struct super_block *sb, u32 segno) +{ + BUG(); +} + +/* + * Returns the bytes consumed by valid objects in this segment. Object headers + * are counted, the segment header is not. + */ +static u32 logfs_valid_bytes(struct super_block *sb, u32 segno, u32 *ec, + gc_level_t *gc_level) +{ + struct logfs_segment_entry se; + u32 ec_level; + + logfs_get_segment_entry(sb, segno, &se); + if (se.ec_level == cpu_to_be32(BADSEG) || + se.valid == cpu_to_be32(RESERVED)) + return RESERVED; + + ec_level = be32_to_cpu(se.ec_level); + *ec = ec_level >> 4; + *gc_level = GC_LEVEL(ec_level & 0xf); + return be32_to_cpu(se.valid); +} + +static void logfs_cleanse_block(struct super_block *sb, u64 ofs, u64 ino, + u64 bix, gc_level_t gc_level) +{ + struct inode *inode; + int err, cookie; + + inode = logfs_safe_iget(sb, ino, &cookie); + err = logfs_rewrite_block(inode, bix, ofs, gc_level, 0); + BUG_ON(err); + logfs_safe_iput(inode, cookie); +} + +static u32 logfs_gc_segment(struct super_block *sb, u32 segno, u8 dist) +{ + struct logfs_super *super = logfs_super(sb); + struct logfs_segment_header sh; + struct logfs_object_header oh; + u64 ofs, ino, bix; + u32 seg_ofs, logical_segno, cleaned = 0; + int err, len, valid; + gc_level_t gc_level; + + LOGFS_BUG_ON(segment_is_reserved(sb, segno), sb); + + btree_insert32(&super->s_reserved_segments, segno, (void *)1, GFP_NOFS); + err = wbuf_read(sb, dev_ofs(sb, segno, 0), sizeof(sh), &sh); + BUG_ON(err); + gc_level = GC_LEVEL(sh.level); + logical_segno = be32_to_cpu(sh.segno); + if (sh.crc != logfs_crc32(&sh, sizeof(sh), 4)) { + logfs_mark_segment_bad(sb, segno); + cleaned = -1; + goto out; + } + + for (seg_ofs = LOGFS_SEGMENT_HEADERSIZE; + seg_ofs + sizeof(oh) < super->s_segsize; ) { + ofs = dev_ofs(sb, logical_segno, seg_ofs); + err = wbuf_read(sb, dev_ofs(sb, segno, seg_ofs), sizeof(oh), + &oh); + BUG_ON(err); + + if (!memchr_inv(&oh, 0xff, sizeof(oh))) + break; + + if (oh.crc != logfs_crc32(&oh, sizeof(oh) - 4, 4)) { + logfs_mark_segment_bad(sb, segno); + cleaned = super->s_segsize - 1; + goto out; + } + + ino = be64_to_cpu(oh.ino); + bix = be64_to_cpu(oh.bix); + len = sizeof(oh) + be16_to_cpu(oh.len); + valid = logfs_is_valid_block(sb, ofs, ino, bix, gc_level); + if (valid == 1) { + logfs_cleanse_block(sb, ofs, ino, bix, gc_level); + cleaned += len; + } else if (valid == 2) { + /* Will be invalid upon journal commit */ + cleaned += len; + } + seg_ofs += len; + } +out: + btree_remove32(&super->s_reserved_segments, segno); + return cleaned; +} + +static struct gc_candidate *add_list(struct gc_candidate *cand, + struct candidate_list *list) +{ + struct rb_node **p = &list->rb_tree.rb_node; + struct rb_node *parent = NULL; + struct gc_candidate *cur; + int comp; + + cand->list = list; + while (*p) { + parent = *p; + cur = rb_entry(parent, struct gc_candidate, rb_node); + + if (list->sort_by_ec) + comp = cand->erase_count < cur->erase_count; + else + comp = cand->valid < cur->valid; + + if (comp) + p = &parent->rb_left; + else + p = &parent->rb_right; + } + rb_link_node(&cand->rb_node, parent, p); + rb_insert_color(&cand->rb_node, &list->rb_tree); + + if (list->count <= list->maxcount) { + list->count++; + return NULL; + } + cand = rb_entry(rb_last(&list->rb_tree), struct gc_candidate, rb_node); + rb_erase(&cand->rb_node, &list->rb_tree); + cand->list = NULL; + return cand; +} + +static void remove_from_list(struct gc_candidate *cand) +{ + struct candidate_list *list = cand->list; + + rb_erase(&cand->rb_node, &list->rb_tree); + list->count--; +} + +static void free_candidate(struct super_block *sb, struct gc_candidate *cand) +{ + struct logfs_super *super = logfs_super(sb); + + btree_remove32(&super->s_cand_tree, cand->segno); + kfree(cand); +} + +u32 get_best_cand(struct super_block *sb, struct candidate_list *list, u32 *ec) +{ + struct gc_candidate *cand; + u32 segno; + + BUG_ON(list->count == 0); + + cand = rb_entry(rb_first(&list->rb_tree), struct gc_candidate, rb_node); + remove_from_list(cand); + segno = cand->segno; + if (ec) + *ec = cand->erase_count; + free_candidate(sb, cand); + return segno; +} + +/* + * We have several lists to manage segments with. The reserve_list is used to + * deal with bad blocks. We try to keep the best (lowest ec) segments on this + * list. + * The free_list contains free segments for normal usage. It usually gets the + * second pick after the reserve_list. But when the free_list is running short + * it is more important to keep the free_list full than to keep a reserve. + * + * Segments that are not free are put onto a per-level low_list. If we have + * to run garbage collection, we pick a candidate from there. All segments on + * those lists should have at least some free space so GC will make progress. + * + * And last we have the ec_list, which is used to pick segments for wear + * leveling. + * + * If all appropriate lists are full, we simply free the candidate and forget + * about that segment for a while. We have better candidates for each purpose. + */ +static void __add_candidate(struct super_block *sb, struct gc_candidate *cand) +{ + struct logfs_super *super = logfs_super(sb); + u32 full = super->s_segsize - LOGFS_SEGMENT_RESERVE; + + if (cand->valid == 0) { + /* 100% free segments */ + log_gc_noisy("add reserve segment %x (ec %x) at %llx\n", + cand->segno, cand->erase_count, + dev_ofs(sb, cand->segno, 0)); + cand = add_list(cand, &super->s_reserve_list); + if (cand) { + log_gc_noisy("add free segment %x (ec %x) at %llx\n", + cand->segno, cand->erase_count, + dev_ofs(sb, cand->segno, 0)); + cand = add_list(cand, &super->s_free_list); + } + } else { + /* good candidates for Garbage Collection */ + if (cand->valid < full) + cand = add_list(cand, &super->s_low_list[cand->dist]); + /* good candidates for wear leveling, + * segments that were recently written get ignored */ + if (cand) + cand = add_list(cand, &super->s_ec_list); + } + if (cand) + free_candidate(sb, cand); +} + +static int add_candidate(struct super_block *sb, u32 segno, u32 valid, u32 ec, + u8 dist) +{ + struct logfs_super *super = logfs_super(sb); + struct gc_candidate *cand; + + cand = kmalloc(sizeof(*cand), GFP_NOFS); + if (!cand) + return -ENOMEM; + + cand->segno = segno; + cand->valid = valid; + cand->erase_count = ec; + cand->dist = dist; + + btree_insert32(&super->s_cand_tree, segno, cand, GFP_NOFS); + __add_candidate(sb, cand); + return 0; +} + +static void remove_segment_from_lists(struct super_block *sb, u32 segno) +{ + struct logfs_super *super = logfs_super(sb); + struct gc_candidate *cand; + + cand = btree_lookup32(&super->s_cand_tree, segno); + if (cand) { + remove_from_list(cand); + free_candidate(sb, cand); + } +} + +static void scan_segment(struct super_block *sb, u32 segno) +{ + u32 valid, ec = 0; + gc_level_t gc_level = 0; + u8 dist; + + if (segment_is_reserved(sb, segno)) + return; + + remove_segment_from_lists(sb, segno); + valid = logfs_valid_bytes(sb, segno, &ec, &gc_level); + if (valid == RESERVED) + return; + + dist = root_distance(sb, gc_level); + add_candidate(sb, segno, valid, ec, dist); +} + +static struct gc_candidate *first_in_list(struct candidate_list *list) +{ + if (list->count == 0) + return NULL; + return rb_entry(rb_first(&list->rb_tree), struct gc_candidate, rb_node); +} + +/* + * Find the best segment for garbage collection. Main criterion is + * the segment requiring the least effort to clean. Secondary + * criterion is to GC on the lowest level available. + * + * So we search the least effort segment on the lowest level first, + * then move up and pick another segment iff is requires significantly + * less effort. Hence the LOGFS_MAX_OBJECTSIZE in the comparison. + */ +static struct gc_candidate *get_candidate(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + int i, max_dist; + struct gc_candidate *cand = NULL, *this; + + max_dist = min(no_free_segments(sb), LOGFS_NO_AREAS); + + for (i = max_dist; i >= 0; i--) { + this = first_in_list(&super->s_low_list[i]); + if (!this) + continue; + if (!cand) + cand = this; + if (this->valid + LOGFS_MAX_OBJECTSIZE <= cand->valid) + cand = this; + } + return cand; +} + +static int __logfs_gc_once(struct super_block *sb, struct gc_candidate *cand) +{ + struct logfs_super *super = logfs_super(sb); + gc_level_t gc_level; + u32 cleaned, valid, segno, ec; + u8 dist; + + if (!cand) { + log_gc("GC attempted, but no candidate found\n"); + return 0; + } + + segno = cand->segno; + dist = cand->dist; + valid = logfs_valid_bytes(sb, segno, &ec, &gc_level); + free_candidate(sb, cand); + log_gc("GC segment #%02x at %llx, %x required, %x free, %x valid, %llx free\n", + segno, (u64)segno << super->s_segshift, + dist, no_free_segments(sb), valid, + super->s_free_bytes); + cleaned = logfs_gc_segment(sb, segno, dist); + log_gc("GC segment #%02x complete - now %x valid\n", segno, + valid - cleaned); + BUG_ON(cleaned != valid); + return 1; +} + +static int logfs_gc_once(struct super_block *sb) +{ + struct gc_candidate *cand; + + cand = get_candidate(sb); + if (cand) + remove_from_list(cand); + return __logfs_gc_once(sb, cand); +} + +/* returns 1 if a wrap occurs, 0 otherwise */ +static int logfs_scan_some(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + u32 segno; + int i, ret = 0; + + segno = super->s_sweeper; + for (i = SCAN_RATIO; i > 0; i--) { + segno++; + if (segno >= super->s_no_segs) { + segno = 0; + ret = 1; + /* Break out of the loop. We want to read a single + * block from the segment size on next invocation if + * SCAN_RATIO is set to match block size + */ + break; + } + + scan_segment(sb, segno); + } + super->s_sweeper = segno; + return ret; +} + +/* + * In principle, this function should loop forever, looking for GC candidates + * and moving data. LogFS is designed in such a way that this loop is + * guaranteed to terminate. + * + * Limiting the loop to some iterations serves purely to catch cases when + * these guarantees have failed. An actual endless loop is an obvious bug + * and should be reported as such. + */ +static void __logfs_gc_pass(struct super_block *sb, int target) +{ + struct logfs_super *super = logfs_super(sb); + struct logfs_block *block; + int round, progress, last_progress = 0; + + if (no_free_segments(sb) >= target && + super->s_no_object_aliases < MAX_OBJ_ALIASES) + return; + + log_gc("__logfs_gc_pass(%x)\n", target); + for (round = 0; round < SCAN_ROUNDS; ) { + if (no_free_segments(sb) >= target) + goto write_alias; + + /* Sync in-memory state with on-medium state in case they + * diverged */ + logfs_write_anchor(super->s_master_inode); + round += logfs_scan_some(sb); + if (no_free_segments(sb) >= target) + goto write_alias; + progress = logfs_gc_once(sb); + if (progress) + last_progress = round; + else if (round - last_progress > 2) + break; + continue; + + /* + * The goto logic is nasty, I just don't know a better way to + * code it. GC is supposed to ensure two things: + * 1. Enough free segments are available. + * 2. The number of aliases is bounded. + * When 1. is achieved, we take a look at 2. and write back + * some alias-containing blocks, if necessary. However, after + * each such write we need to go back to 1., as writes can + * consume free segments. + */ +write_alias: + if (super->s_no_object_aliases < MAX_OBJ_ALIASES) + return; + if (list_empty(&super->s_object_alias)) { + /* All aliases are still in btree */ + return; + } + log_gc("Write back one alias\n"); + block = list_entry(super->s_object_alias.next, + struct logfs_block, alias_list); + block->ops->write_block(block); + /* + * To round off the nasty goto logic, we reset round here. It + * is a safety-net for GC not making any progress and limited + * to something reasonably small. If incremented it for every + * single alias, the loop could terminate rather quickly. + */ + round = 0; + } + LOGFS_BUG(sb); +} + +static int wl_ratelimit(struct super_block *sb, u64 *next_event) +{ + struct logfs_super *super = logfs_super(sb); + + if (*next_event < super->s_gec) { + *next_event = super->s_gec + WL_RATELIMIT; + return 0; + } + return 1; +} + +static void logfs_wl_pass(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + struct gc_candidate *wl_cand, *free_cand; + + if (wl_ratelimit(sb, &super->s_wl_gec_ostore)) + return; + + wl_cand = first_in_list(&super->s_ec_list); + if (!wl_cand) + return; + free_cand = first_in_list(&super->s_free_list); + if (!free_cand) + return; + + if (wl_cand->erase_count < free_cand->erase_count + WL_DELTA) { + remove_from_list(wl_cand); + __logfs_gc_once(sb, wl_cand); + } +} + +/* + * The journal needs wear leveling as well. But moving the journal is an + * expensive operation so we try to avoid it as much as possible. And if we + * have to do it, we move the whole journal, not individual segments. + * + * Ratelimiting is not strictly necessary here, it mainly serves to avoid the + * calculations. First we check whether moving the journal would be a + * significant improvement. That means that a) the current journal segments + * have more wear than the future journal segments and b) the current journal + * segments have more wear than normal ostore segments. + * Rationale for b) is that we don't have to move the journal if it is aging + * less than the ostore, even if the reserve segments age even less (they are + * excluded from wear leveling, after all). + * Next we check that the superblocks have less wear than the journal. Since + * moving the journal requires writing the superblocks, we have to protect the + * superblocks even more than the journal. + * + * Also we double the acceptable wear difference, compared to ostore wear + * leveling. Journal data is read and rewritten rapidly, comparatively. So + * soft errors have much less time to accumulate and we allow the journal to + * be a bit worse than the ostore. + */ +static void logfs_journal_wl_pass(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + struct gc_candidate *cand; + u32 min_journal_ec = -1, max_reserve_ec = 0; + int i; + + if (wl_ratelimit(sb, &super->s_wl_gec_journal)) + return; + + if (super->s_reserve_list.count < super->s_no_journal_segs) { + /* Reserve is not full enough to move complete journal */ + return; + } + + journal_for_each(i) + if (super->s_journal_seg[i]) + min_journal_ec = min(min_journal_ec, + super->s_journal_ec[i]); + cand = rb_entry(rb_first(&super->s_free_list.rb_tree), + struct gc_candidate, rb_node); + max_reserve_ec = cand->erase_count; + for (i = 0; i < 2; i++) { + struct logfs_segment_entry se; + u32 segno = seg_no(sb, super->s_sb_ofs[i]); + u32 ec; + + logfs_get_segment_entry(sb, segno, &se); + ec = be32_to_cpu(se.ec_level) >> 4; + max_reserve_ec = max(max_reserve_ec, ec); + } + + if (min_journal_ec > max_reserve_ec + 2 * WL_DELTA) { + do_logfs_journal_wl_pass(sb); + } +} + +void logfs_gc_pass(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + + //BUG_ON(mutex_trylock(&logfs_super(sb)->s_w_mutex)); + /* Write journal before free space is getting saturated with dirty + * objects. + */ + if (super->s_dirty_used_bytes + super->s_dirty_free_bytes + + LOGFS_MAX_OBJECTSIZE >= super->s_free_bytes) + logfs_write_anchor(super->s_master_inode); + __logfs_gc_pass(sb, logfs_super(sb)->s_total_levels); + logfs_wl_pass(sb); + logfs_journal_wl_pass(sb); +} + +static int check_area(struct super_block *sb, int i) +{ + struct logfs_super *super = logfs_super(sb); + struct logfs_area *area = super->s_area[i]; + struct logfs_object_header oh; + u32 segno = area->a_segno; + u32 ofs = area->a_used_bytes; + __be32 crc; + int err; + + if (!area->a_is_open) + return 0; + + for (ofs = area->a_used_bytes; + ofs <= super->s_segsize - sizeof(oh); + ofs += (u32)be16_to_cpu(oh.len) + sizeof(oh)) { + err = wbuf_read(sb, dev_ofs(sb, segno, ofs), sizeof(oh), &oh); + if (err) + return err; + + if (!memchr_inv(&oh, 0xff, sizeof(oh))) + break; + + crc = logfs_crc32(&oh, sizeof(oh) - 4, 4); + if (crc != oh.crc) { + printk(KERN_INFO "interrupted header at %llx\n", + dev_ofs(sb, segno, ofs)); + return 0; + } + } + if (ofs != area->a_used_bytes) { + printk(KERN_INFO "%x bytes unaccounted data found at %llx\n", + ofs - area->a_used_bytes, + dev_ofs(sb, segno, area->a_used_bytes)); + area->a_used_bytes = ofs; + } + return 0; +} + +int logfs_check_areas(struct super_block *sb) +{ + int i, err; + + for_each_area(i) { + err = check_area(sb, i); + if (err) + return err; + } + return 0; +} + +static void logfs_init_candlist(struct candidate_list *list, int maxcount, + int sort_by_ec) +{ + list->count = 0; + list->maxcount = maxcount; + list->sort_by_ec = sort_by_ec; + list->rb_tree = RB_ROOT; +} + +int logfs_init_gc(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + int i; + + btree_init_mempool32(&super->s_cand_tree, super->s_btree_pool); + logfs_init_candlist(&super->s_free_list, LIST_SIZE + SCAN_RATIO, 1); + logfs_init_candlist(&super->s_reserve_list, + super->s_bad_seg_reserve, 1); + for_each_area(i) + logfs_init_candlist(&super->s_low_list[i], LIST_SIZE, 0); + logfs_init_candlist(&super->s_ec_list, LIST_SIZE, 1); + return 0; +} + +static void logfs_cleanup_list(struct super_block *sb, + struct candidate_list *list) +{ + struct gc_candidate *cand; + + while (list->count) { + cand = rb_entry(list->rb_tree.rb_node, struct gc_candidate, + rb_node); + remove_from_list(cand); + free_candidate(sb, cand); + } + BUG_ON(list->rb_tree.rb_node); +} + +void logfs_cleanup_gc(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + int i; + + if (!super->s_free_list.count) + return; + + /* + * FIXME: The btree may still contain a single empty node. So we + * call the grim visitor to clean up that mess. Btree code should + * do it for us, really. + */ + btree_grim_visitor32(&super->s_cand_tree, 0, NULL); + logfs_cleanup_list(sb, &super->s_free_list); + logfs_cleanup_list(sb, &super->s_reserve_list); + for_each_area(i) + logfs_cleanup_list(sb, &super->s_low_list[i]); + logfs_cleanup_list(sb, &super->s_ec_list); +} diff --git a/fs/logfs/inode.c b/fs/logfs/inode.c new file mode 100644 index 00000000000..6d08b376264 --- /dev/null +++ b/fs/logfs/inode.c @@ -0,0 +1,417 @@ +/* + * fs/logfs/inode.c - inode handling code + * + * As should be obvious for Linux kernel code, license is GPLv2 + * + * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org> + */ +#include "logfs.h" +#include <linux/writeback.h> +#include <linux/backing-dev.h> + +/* + * How soon to reuse old inode numbers? LogFS doesn't store deleted inodes + * on the medium. It therefore also lacks a method to store the previous + * generation number for deleted inodes. Instead a single generation number + * is stored which will be used for new inodes. Being just a 32bit counter, + * this can obvious wrap relatively quickly. So we only reuse inodes if we + * know that a fair number of inodes can be created before we have to increment + * the generation again - effectively adding some bits to the counter. + * But being too aggressive here means we keep a very large and very sparse + * inode file, wasting space on indirect blocks. + * So what is a good value? Beats me. 64k seems moderately bad on both + * fronts, so let's use that for now... + * + * NFS sucks, as everyone already knows. + */ +#define INOS_PER_WRAP (0x10000) + +/* + * Logfs' requirement to read inodes for garbage collection makes life a bit + * harder. GC may have to read inodes that are in I_FREEING state, when they + * are being written out - and waiting for GC to make progress, naturally. + * + * So we cannot just call iget() or some variant of it, but first have to check + * wether the inode in question might be in I_FREEING state. Therefore we + * maintain our own per-sb list of "almost deleted" inodes and check against + * that list first. Normally this should be at most 1-2 entries long. + * + * Also, inodes have logfs-specific reference counting on top of what the vfs + * does. When .destroy_inode is called, normally the reference count will drop + * to zero and the inode gets deleted. But if GC accessed the inode, its + * refcount will remain nonzero and final deletion will have to wait. + * + * As a result we have two sets of functions to get/put inodes: + * logfs_safe_iget/logfs_safe_iput - safe to call from GC context + * logfs_iget/iput - normal version + */ +static struct kmem_cache *logfs_inode_cache; + +static DEFINE_SPINLOCK(logfs_inode_lock); + +static void logfs_inode_setops(struct inode *inode) +{ + switch (inode->i_mode & S_IFMT) { + case S_IFDIR: + inode->i_op = &logfs_dir_iops; + inode->i_fop = &logfs_dir_fops; + inode->i_mapping->a_ops = &logfs_reg_aops; + break; + case S_IFREG: + inode->i_op = &logfs_reg_iops; + inode->i_fop = &logfs_reg_fops; + inode->i_mapping->a_ops = &logfs_reg_aops; + break; + case S_IFLNK: + inode->i_op = &logfs_symlink_iops; + inode->i_mapping->a_ops = &logfs_reg_aops; + break; + case S_IFSOCK: /* fall through */ + case S_IFBLK: /* fall through */ + case S_IFCHR: /* fall through */ + case S_IFIFO: + init_special_inode(inode, inode->i_mode, inode->i_rdev); + break; + default: + BUG(); + } +} + +static struct inode *__logfs_iget(struct super_block *sb, ino_t ino) +{ + struct inode *inode = iget_locked(sb, ino); + int err; + + if (!inode) + return ERR_PTR(-ENOMEM); + if (!(inode->i_state & I_NEW)) + return inode; + + err = logfs_read_inode(inode); + if (err || inode->i_nlink == 0) { + /* inode->i_nlink == 0 can be true when called from + * block validator */ + /* set i_nlink to 0 to prevent caching */ + inode->i_nlink = 0; + logfs_inode(inode)->li_flags |= LOGFS_IF_ZOMBIE; + iget_failed(inode); + if (!err) + err = -ENOENT; + return ERR_PTR(err); + } + + logfs_inode_setops(inode); + unlock_new_inode(inode); + return inode; +} + +struct inode *logfs_iget(struct super_block *sb, ino_t ino) +{ + BUG_ON(ino == LOGFS_INO_MASTER); + BUG_ON(ino == LOGFS_INO_SEGFILE); + return __logfs_iget(sb, ino); +} + +/* + * is_cached is set to 1 if we hand out a cached inode, 0 otherwise. + * this allows logfs_iput to do the right thing later + */ +struct inode *logfs_safe_iget(struct super_block *sb, ino_t ino, int *is_cached) +{ + struct logfs_super *super = logfs_super(sb); + struct logfs_inode *li; + + if (ino == LOGFS_INO_MASTER) + return super->s_master_inode; + if (ino == LOGFS_INO_SEGFILE) + return super->s_segfile_inode; + + spin_lock(&logfs_inode_lock); + list_for_each_entry(li, &super->s_freeing_list, li_freeing_list) + if (li->vfs_inode.i_ino == ino) { + li->li_refcount++; + spin_unlock(&logfs_inode_lock); + *is_cached = 1; + return &li->vfs_inode; + } + spin_unlock(&logfs_inode_lock); + + *is_cached = 0; + return __logfs_iget(sb, ino); +} + +static void __logfs_destroy_inode(struct inode *inode) +{ + struct logfs_inode *li = logfs_inode(inode); + + BUG_ON(li->li_block); + list_del(&li->li_freeing_list); + kmem_cache_free(logfs_inode_cache, li); +} + +static void logfs_destroy_inode(struct inode *inode) +{ + struct logfs_inode *li = logfs_inode(inode); + + BUG_ON(list_empty(&li->li_freeing_list)); + spin_lock(&logfs_inode_lock); + li->li_refcount--; + if (li->li_refcount == 0) + __logfs_destroy_inode(inode); + spin_unlock(&logfs_inode_lock); +} + +void logfs_safe_iput(struct inode *inode, int is_cached) +{ + if (inode->i_ino == LOGFS_INO_MASTER) + return; + if (inode->i_ino == LOGFS_INO_SEGFILE) + return; + + if (is_cached) { + logfs_destroy_inode(inode); + return; + } + + iput(inode); +} + +static void logfs_init_inode(struct super_block *sb, struct inode *inode) +{ + struct logfs_inode *li = logfs_inode(inode); + int i; + + li->li_flags = 0; + li->li_height = 0; + li->li_used_bytes = 0; + li->li_block = NULL; + inode->i_uid = 0; + inode->i_gid = 0; + inode->i_size = 0; + inode->i_blocks = 0; + inode->i_ctime = CURRENT_TIME; + inode->i_mtime = CURRENT_TIME; + inode->i_nlink = 1; + INIT_LIST_HEAD(&li->li_freeing_list); + + for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++) + li->li_data[i] = 0; + + return; +} + +static struct inode *logfs_alloc_inode(struct super_block *sb) +{ + struct logfs_inode *li; + + li = kmem_cache_alloc(logfs_inode_cache, GFP_NOFS); + if (!li) + return NULL; + logfs_init_inode(sb, &li->vfs_inode); + return &li->vfs_inode; +} + +/* + * In logfs inodes are written to an inode file. The inode file, like any + * other file, is managed with a inode. The inode file's inode, aka master + * inode, requires special handling in several respects. First, it cannot be + * written to the inode file, so it is stored in the journal instead. + * + * Secondly, this inode cannot be written back and destroyed before all other + * inodes have been written. The ordering is important. Linux' VFS is happily + * unaware of the ordering constraint and would ordinarily destroy the master + * inode at umount time while other inodes are still in use and dirty. Not + * good. + * + * So logfs makes sure the master inode is not written until all other inodes + * have been destroyed. Sadly, this method has another side-effect. The VFS + * will notice one remaining inode and print a frightening warning message. + * Worse, it is impossible to judge whether such a warning was caused by the + * master inode or any other inodes have leaked as well. + * + * Our attempt of solving this is with logfs_new_meta_inode() below. Its + * purpose is to create a new inode that will not trigger the warning if such + * an inode is still in use. An ugly hack, no doubt. Suggections for + * improvement are welcome. + */ +struct inode *logfs_new_meta_inode(struct super_block *sb, u64 ino) +{ + struct inode *inode; + + inode = logfs_alloc_inode(sb); + if (!inode) + return ERR_PTR(-ENOMEM); + + inode->i_mode = S_IFREG; + inode->i_ino = ino; + inode->i_sb = sb; + + /* This is a blatant copy of alloc_inode code. We'd need alloc_inode + * to be nonstatic, alas. */ + { + struct address_space * const mapping = &inode->i_data; + + mapping->a_ops = &logfs_reg_aops; + mapping->host = inode; + mapping->flags = 0; + mapping_set_gfp_mask(mapping, GFP_NOFS); + mapping->assoc_mapping = NULL; + mapping->backing_dev_info = &default_backing_dev_info; + inode->i_mapping = mapping; + inode->i_nlink = 1; + } + + return inode; +} + +struct inode *logfs_read_meta_inode(struct super_block *sb, u64 ino) +{ + struct inode *inode; + int err; + + inode = logfs_new_meta_inode(sb, ino); + if (IS_ERR(inode)) + return inode; + + err = logfs_read_inode(inode); + if (err) { + destroy_meta_inode(inode); + return ERR_PTR(err); + } + logfs_inode_setops(inode); + return inode; +} + +static int logfs_write_inode(struct inode *inode, int do_sync) +{ + int ret; + long flags = WF_LOCK; + + /* Can only happen if creat() failed. Safe to skip. */ + if (logfs_inode(inode)->li_flags & LOGFS_IF_STILLBORN) + return 0; + + ret = __logfs_write_inode(inode, flags); + LOGFS_BUG_ON(ret, inode->i_sb); + return ret; +} + +void destroy_meta_inode(struct inode *inode) +{ + if (inode) { + if (inode->i_data.nrpages) + truncate_inode_pages(&inode->i_data, 0); + logfs_clear_inode(inode); + kmem_cache_free(logfs_inode_cache, logfs_inode(inode)); + } +} + +/* called with inode_lock held */ +static void logfs_drop_inode(struct inode *inode) +{ + struct logfs_super *super = logfs_super(inode->i_sb); + struct logfs_inode *li = logfs_inode(inode); + + spin_lock(&logfs_inode_lock); + list_move(&li->li_freeing_list, &super->s_freeing_list); + spin_unlock(&logfs_inode_lock); + generic_drop_inode(inode); +} + +static void logfs_set_ino_generation(struct super_block *sb, + struct inode *inode) +{ + struct logfs_super *super = logfs_super(sb); + u64 ino; + + mutex_lock(&super->s_journal_mutex); + ino = logfs_seek_hole(super->s_master_inode, super->s_last_ino); + super->s_last_ino = ino; + super->s_inos_till_wrap--; + if (super->s_inos_till_wrap < 0) { + super->s_last_ino = LOGFS_RESERVED_INOS; + super->s_generation++; + super->s_inos_till_wrap = INOS_PER_WRAP; + } + inode->i_ino = ino; + inode->i_generation = super->s_generation; + mutex_unlock(&super->s_journal_mutex); +} + +struct inode *logfs_new_inode(struct inode *dir, int mode) +{ + struct super_block *sb = dir->i_sb; + struct inode *inode; + + inode = new_inode(sb); + if (!inode) + return ERR_PTR(-ENOMEM); + + logfs_init_inode(sb, inode); + + /* inherit parent flags */ + logfs_inode(inode)->li_flags |= + logfs_inode(dir)->li_flags & LOGFS_FL_INHERITED; + + inode->i_mode = mode; + logfs_set_ino_generation(sb, inode); + + inode->i_uid = current_fsuid(); + inode->i_gid = current_fsgid(); + if (dir->i_mode & S_ISGID) { + inode->i_gid = dir->i_gid; + if (S_ISDIR(mode)) + inode->i_mode |= S_ISGID; + } + + logfs_inode_setops(inode); + insert_inode_hash(inode); + + return inode; +} + +static void logfs_init_once(void *_li) +{ + struct logfs_inode *li = _li; + int i; + + li->li_flags = 0; + li->li_used_bytes = 0; + li->li_refcount = 1; + for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++) + li->li_data[i] = 0; + inode_init_once(&li->vfs_inode); +} + +static int logfs_sync_fs(struct super_block *sb, int wait) +{ + /* FIXME: write anchor */ + logfs_super(sb)->s_devops->sync(sb); + return 0; +} + +const struct super_operations logfs_super_operations = { + .alloc_inode = logfs_alloc_inode, + .clear_inode = logfs_clear_inode, + .delete_inode = logfs_delete_inode, + .destroy_inode = logfs_destroy_inode, + .drop_inode = logfs_drop_inode, + .write_inode = logfs_write_inode, + .statfs = logfs_statfs, + .sync_fs = logfs_sync_fs, +}; + +int logfs_init_inode_cache(void) +{ + logfs_inode_cache = kmem_cache_create("logfs_inode_cache", + sizeof(struct logfs_inode), 0, SLAB_RECLAIM_ACCOUNT, + logfs_init_once); + if (!logfs_inode_cache) + return -ENOMEM; + return 0; +} + +void logfs_destroy_inode_cache(void) +{ + kmem_cache_destroy(logfs_inode_cache); +} diff --git a/fs/logfs/journal.c b/fs/logfs/journal.c new file mode 100644 index 00000000000..7a023dbba9f --- /dev/null +++ b/fs/logfs/journal.c @@ -0,0 +1,879 @@ +/* + * fs/logfs/journal.c - journal handling code + * + * As should be obvious for Linux kernel code, license is GPLv2 + * + * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org> + */ +#include "logfs.h" + +static void logfs_calc_free(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + u64 reserve, no_segs = super->s_no_segs; + s64 free; + int i; + + /* superblock segments */ + no_segs -= 2; + super->s_no_journal_segs = 0; + /* journal */ + journal_for_each(i) + if (super->s_journal_seg[i]) { + no_segs--; + super->s_no_journal_segs++; + } + + /* open segments plus one extra per level for GC */ + no_segs -= 2 * super->s_total_levels; + + free = no_segs * (super->s_segsize - LOGFS_SEGMENT_RESERVE); + free -= super->s_used_bytes; + /* just a bit extra */ + free -= super->s_total_levels * 4096; + + /* Bad blocks are 'paid' for with speed reserve - the filesystem + * simply gets slower as bad blocks accumulate. Until the bad blocks + * exceed the speed reserve - then the filesystem gets smaller. + */ + reserve = super->s_bad_segments + super->s_bad_seg_reserve; + reserve *= super->s_segsize - LOGFS_SEGMENT_RESERVE; + reserve = max(reserve, super->s_speed_reserve); + free -= reserve; + if (free < 0) + free = 0; + + super->s_free_bytes = free; +} + +static void reserve_sb_and_journal(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + struct btree_head32 *head = &super->s_reserved_segments; + int i, err; + + err = btree_insert32(head, seg_no(sb, super->s_sb_ofs[0]), (void *)1, + GFP_KERNEL); + BUG_ON(err); + + err = btree_insert32(head, seg_no(sb, super->s_sb_ofs[1]), (void *)1, + GFP_KERNEL); + BUG_ON(err); + + journal_for_each(i) { + if (!super->s_journal_seg[i]) + continue; + err = btree_insert32(head, super->s_journal_seg[i], (void *)1, + GFP_KERNEL); + BUG_ON(err); + } +} + +static void read_dynsb(struct super_block *sb, + struct logfs_je_dynsb *dynsb) +{ + struct logfs_super *super = logfs_super(sb); + + super->s_gec = be64_to_cpu(dynsb->ds_gec); + super->s_sweeper = be64_to_cpu(dynsb->ds_sweeper); + super->s_victim_ino = be64_to_cpu(dynsb->ds_victim_ino); + super->s_rename_dir = be64_to_cpu(dynsb->ds_rename_dir); + super->s_rename_pos = be64_to_cpu(dynsb->ds_rename_pos); + super->s_used_bytes = be64_to_cpu(dynsb->ds_used_bytes); + super->s_generation = be32_to_cpu(dynsb->ds_generation); +} + +static void read_anchor(struct super_block *sb, + struct logfs_je_anchor *da) +{ + struct logfs_super *super = logfs_super(sb); + struct inode *inode = super->s_master_inode; + struct logfs_inode *li = logfs_inode(inode); + int i; + + super->s_last_ino = be64_to_cpu(da->da_last_ino); + li->li_flags = 0; + li->li_height = da->da_height; + i_size_write(inode, be64_to_cpu(da->da_size)); + li->li_used_bytes = be64_to_cpu(da->da_used_bytes); + + for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++) + li->li_data[i] = be64_to_cpu(da->da_data[i]); +} + +static void read_erasecount(struct super_block *sb, + struct logfs_je_journal_ec *ec) +{ + struct logfs_super *super = logfs_super(sb); + int i; + + journal_for_each(i) + super->s_journal_ec[i] = be32_to_cpu(ec->ec[i]); +} + +static int read_area(struct super_block *sb, struct logfs_je_area *a) +{ + struct logfs_super *super = logfs_super(sb); + struct logfs_area *area = super->s_area[a->gc_level]; + u64 ofs; + u32 writemask = ~(super->s_writesize - 1); + + if (a->gc_level >= LOGFS_NO_AREAS) + return -EIO; + if (a->vim != VIM_DEFAULT) + return -EIO; /* TODO: close area and continue */ + + area->a_used_bytes = be32_to_cpu(a->used_bytes); + area->a_written_bytes = area->a_used_bytes & writemask; + area->a_segno = be32_to_cpu(a->segno); + if (area->a_segno) + area->a_is_open = 1; + + ofs = dev_ofs(sb, area->a_segno, area->a_written_bytes); + if (super->s_writesize > 1) + logfs_buf_recover(area, ofs, a + 1, super->s_writesize); + else + logfs_buf_recover(area, ofs, NULL, 0); + return 0; +} + +static void *unpack(void *from, void *to) +{ + struct logfs_journal_header *jh = from; + void *data = from + sizeof(struct logfs_journal_header); + int err; + size_t inlen, outlen; + + inlen = be16_to_cpu(jh->h_len); + outlen = be16_to_cpu(jh->h_datalen); + + if (jh->h_compr == COMPR_NONE) + memcpy(to, data, inlen); + else { + err = logfs_uncompress(data, to, inlen, outlen); + BUG_ON(err); + } + return to; +} + +static int __read_je_header(struct super_block *sb, u64 ofs, + struct logfs_journal_header *jh) +{ + struct logfs_super *super = logfs_super(sb); + size_t bufsize = max_t(size_t, sb->s_blocksize, super->s_writesize) + + MAX_JOURNAL_HEADER; + u16 type, len, datalen; + int err; + + /* read header only */ + err = wbuf_read(sb, ofs, sizeof(*jh), jh); + if (err) + return err; + type = be16_to_cpu(jh->h_type); + len = be16_to_cpu(jh->h_len); + datalen = be16_to_cpu(jh->h_datalen); + if (len > sb->s_blocksize) + return -EIO; + if ((type < JE_FIRST) || (type > JE_LAST)) + return -EIO; + if (datalen > bufsize) + return -EIO; + return 0; +} + +static int __read_je_payload(struct super_block *sb, u64 ofs, + struct logfs_journal_header *jh) +{ + u16 len; + int err; + + len = be16_to_cpu(jh->h_len); + err = wbuf_read(sb, ofs + sizeof(*jh), len, jh + 1); + if (err) + return err; + if (jh->h_crc != logfs_crc32(jh, len + sizeof(*jh), 4)) { + /* Old code was confused. It forgot about the header length + * and stopped calculating the crc 16 bytes before the end + * of data - ick! + * FIXME: Remove this hack once the old code is fixed. + */ + if (jh->h_crc == logfs_crc32(jh, len, 4)) + WARN_ON_ONCE(1); + else + return -EIO; + } + return 0; +} + +/* + * jh needs to be large enough to hold the complete entry, not just the header + */ +static int __read_je(struct super_block *sb, u64 ofs, + struct logfs_journal_header *jh) +{ + int err; + + err = __read_je_header(sb, ofs, jh); + if (err) + return err; + return __read_je_payload(sb, ofs, jh); +} + +static int read_je(struct super_block *sb, u64 ofs) +{ + struct logfs_super *super = logfs_super(sb); + struct logfs_journal_header *jh = super->s_compressed_je; + void *scratch = super->s_je; + u16 type, datalen; + int err; + + err = __read_je(sb, ofs, jh); + if (err) + return err; + type = be16_to_cpu(jh->h_type); + datalen = be16_to_cpu(jh->h_datalen); + + switch (type) { + case JE_DYNSB: + read_dynsb(sb, unpack(jh, scratch)); + break; + case JE_ANCHOR: + read_anchor(sb, unpack(jh, scratch)); + break; + case JE_ERASECOUNT: + read_erasecount(sb, unpack(jh, scratch)); + break; + case JE_AREA: + read_area(sb, unpack(jh, scratch)); + break; + case JE_OBJ_ALIAS: + err = logfs_load_object_aliases(sb, unpack(jh, scratch), + datalen); + break; + default: + WARN_ON_ONCE(1); + return -EIO; + } + return err; +} + +static int logfs_read_segment(struct super_block *sb, u32 segno) +{ + struct logfs_super *super = logfs_super(sb); + struct logfs_journal_header *jh = super->s_compressed_je; + u64 ofs, seg_ofs = dev_ofs(sb, segno, 0); + u32 h_ofs, last_ofs = 0; + u16 len, datalen, last_len; + int i, err; + + /* search for most recent commit */ + for (h_ofs = 0; h_ofs < super->s_segsize; h_ofs += sizeof(*jh)) { + ofs = seg_ofs + h_ofs; + err = __read_je_header(sb, ofs, jh); + if (err) + continue; + if (jh->h_type != cpu_to_be16(JE_COMMIT)) + continue; + err = __read_je_payload(sb, ofs, jh); + if (err) + continue; + len = be16_to_cpu(jh->h_len); + datalen = be16_to_cpu(jh->h_datalen); + if ((datalen > sizeof(super->s_je_array)) || + (datalen % sizeof(__be64))) + continue; + last_ofs = h_ofs; + last_len = datalen; + h_ofs += ALIGN(len, sizeof(*jh)) - sizeof(*jh); + } + /* read commit */ + if (last_ofs == 0) + return -ENOENT; + ofs = seg_ofs + last_ofs; + log_journal("Read commit from %llx\n", ofs); + err = __read_je(sb, ofs, jh); + BUG_ON(err); /* We should have caught it in the scan loop already */ + if (err) + return err; + /* uncompress */ + unpack(jh, super->s_je_array); + super->s_no_je = last_len / sizeof(__be64); + /* iterate over array */ + for (i = 0; i < super->s_no_je; i++) { + err = read_je(sb, be64_to_cpu(super->s_je_array[i])); + if (err) + return err; + } + super->s_journal_area->a_segno = segno; + return 0; +} + +static u64 read_gec(struct super_block *sb, u32 segno) +{ + struct logfs_segment_header sh; + __be32 crc; + int err; + + if (!segno) + return 0; + err = wbuf_read(sb, dev_ofs(sb, segno, 0), sizeof(sh), &sh); + if (err) + return 0; + crc = logfs_crc32(&sh, sizeof(sh), 4); + if (crc != sh.crc) { + WARN_ON(sh.gec != cpu_to_be64(0xffffffffffffffffull)); + /* Most likely it was just erased */ + return 0; + } + return be64_to_cpu(sh.gec); +} + +static int logfs_read_journal(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + u64 gec[LOGFS_JOURNAL_SEGS], max; + u32 segno; + int i, max_i; + + max = 0; + max_i = -1; + journal_for_each(i) { + segno = super->s_journal_seg[i]; + gec[i] = read_gec(sb, super->s_journal_seg[i]); + if (gec[i] > max) { + max = gec[i]; + max_i = i; + } + } + if (max_i == -1) + return -EIO; + /* FIXME: Try older segments in case of error */ + return logfs_read_segment(sb, super->s_journal_seg[max_i]); +} + +/* + * First search the current segment (outer loop), then pick the next segment + * in the array, skipping any zero entries (inner loop). + */ +static void journal_get_free_segment(struct logfs_area *area) +{ + struct logfs_super *super = logfs_super(area->a_sb); + int i; + + journal_for_each(i) { + if (area->a_segno != super->s_journal_seg[i]) + continue; + + do { + i++; + if (i == LOGFS_JOURNAL_SEGS) + i = 0; + } while (!super->s_journal_seg[i]); + + area->a_segno = super->s_journal_seg[i]; + area->a_erase_count = ++(super->s_journal_ec[i]); + log_journal("Journal now at %x (ec %x)\n", area->a_segno, + area->a_erase_count); + return; + } + BUG(); +} + +static void journal_get_erase_count(struct logfs_area *area) +{ + /* erase count is stored globally and incremented in + * journal_get_free_segment() - nothing to do here */ +} + +static int journal_erase_segment(struct logfs_area *area) +{ + struct super_block *sb = area->a_sb; + struct logfs_segment_header sh; + u64 ofs; + int err; + + err = logfs_erase_segment(sb, area->a_segno); + if (err) + return err; + + sh.pad = 0; + sh.type = SEG_JOURNAL; + sh.level = 0; + sh.segno = cpu_to_be32(area->a_segno); + sh.ec = cpu_to_be32(area->a_erase_count); + sh.gec = cpu_to_be64(logfs_super(sb)->s_gec); + sh.crc = logfs_crc32(&sh, sizeof(sh), 4); + + /* This causes a bug in segment.c. Not yet. */ + //logfs_set_segment_erased(sb, area->a_segno, area->a_erase_count, 0); + + ofs = dev_ofs(sb, area->a_segno, 0); + area->a_used_bytes = ALIGN(sizeof(sh), 16); + logfs_buf_write(area, ofs, &sh, sizeof(sh)); + return 0; +} + +static size_t __logfs_write_header(struct logfs_super *super, + struct logfs_journal_header *jh, size_t len, size_t datalen, + u16 type, u8 compr) +{ + jh->h_len = cpu_to_be16(len); + jh->h_type = cpu_to_be16(type); + jh->h_version = cpu_to_be16(++super->s_last_version); + jh->h_datalen = cpu_to_be16(datalen); + jh->h_compr = compr; + jh->h_pad[0] = 'H'; + jh->h_pad[1] = 'A'; + jh->h_pad[2] = 'T'; + jh->h_crc = logfs_crc32(jh, len + sizeof(*jh), 4); + return ALIGN(len, 16) + sizeof(*jh); +} + +static size_t logfs_write_header(struct logfs_super *super, + struct logfs_journal_header *jh, size_t datalen, u16 type) +{ + size_t len = datalen; + + return __logfs_write_header(super, jh, len, datalen, type, COMPR_NONE); +} + +static inline size_t logfs_journal_erasecount_size(struct logfs_super *super) +{ + return LOGFS_JOURNAL_SEGS * sizeof(__be32); +} + +static void *logfs_write_erasecount(struct super_block *sb, void *_ec, + u16 *type, size_t *len) +{ + struct logfs_super *super = logfs_super(sb); + struct logfs_je_journal_ec *ec = _ec; + int i; + + journal_for_each(i) + ec->ec[i] = cpu_to_be32(super->s_journal_ec[i]); + *type = JE_ERASECOUNT; + *len = logfs_journal_erasecount_size(super); + return ec; +} + +static void account_shadow(void *_shadow, unsigned long _sb, u64 ignore, + size_t ignore2) +{ + struct logfs_shadow *shadow = _shadow; + struct super_block *sb = (void *)_sb; + struct logfs_super *super = logfs_super(sb); + + /* consume new space */ + super->s_free_bytes -= shadow->new_len; + super->s_used_bytes += shadow->new_len; + super->s_dirty_used_bytes -= shadow->new_len; + + /* free up old space */ + super->s_free_bytes += shadow->old_len; + super->s_used_bytes -= shadow->old_len; + super->s_dirty_free_bytes -= shadow->old_len; + + logfs_set_segment_used(sb, shadow->old_ofs, -shadow->old_len); + logfs_set_segment_used(sb, shadow->new_ofs, shadow->new_len); + + log_journal("account_shadow(%llx, %llx, %x) %llx->%llx %x->%x\n", + shadow->ino, shadow->bix, shadow->gc_level, + shadow->old_ofs, shadow->new_ofs, + shadow->old_len, shadow->new_len); + mempool_free(shadow, super->s_shadow_pool); +} + +static void account_shadows(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + struct inode *inode = super->s_master_inode; + struct logfs_inode *li = logfs_inode(inode); + struct shadow_tree *tree = &super->s_shadow_tree; + + btree_grim_visitor64(&tree->new, (unsigned long)sb, account_shadow); + btree_grim_visitor64(&tree->old, (unsigned long)sb, account_shadow); + + if (li->li_block) { + /* + * We never actually use the structure, when attached to the + * master inode. But it is easier to always free it here than + * to have checks in several places elsewhere when allocating + * it. + */ + li->li_block->ops->free_block(sb, li->li_block); + } + BUG_ON((s64)li->li_used_bytes < 0); +} + +static void *__logfs_write_anchor(struct super_block *sb, void *_da, + u16 *type, size_t *len) +{ + struct logfs_super *super = logfs_super(sb); + struct logfs_je_anchor *da = _da; + struct inode *inode = super->s_master_inode; + struct logfs_inode *li = logfs_inode(inode); + int i; + + da->da_height = li->li_height; + da->da_last_ino = cpu_to_be64(super->s_last_ino); + da->da_size = cpu_to_be64(i_size_read(inode)); + da->da_used_bytes = cpu_to_be64(li->li_used_bytes); + for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++) + da->da_data[i] = cpu_to_be64(li->li_data[i]); + *type = JE_ANCHOR; + *len = sizeof(*da); + return da; +} + +static void *logfs_write_dynsb(struct super_block *sb, void *_dynsb, + u16 *type, size_t *len) +{ + struct logfs_super *super = logfs_super(sb); + struct logfs_je_dynsb *dynsb = _dynsb; + + dynsb->ds_gec = cpu_to_be64(super->s_gec); + dynsb->ds_sweeper = cpu_to_be64(super->s_sweeper); + dynsb->ds_victim_ino = cpu_to_be64(super->s_victim_ino); + dynsb->ds_rename_dir = cpu_to_be64(super->s_rename_dir); + dynsb->ds_rename_pos = cpu_to_be64(super->s_rename_pos); + dynsb->ds_used_bytes = cpu_to_be64(super->s_used_bytes); + dynsb->ds_generation = cpu_to_be32(super->s_generation); + *type = JE_DYNSB; + *len = sizeof(*dynsb); + return dynsb; +} + +static void write_wbuf(struct super_block *sb, struct logfs_area *area, + void *wbuf) +{ + struct logfs_super *super = logfs_super(sb); + struct address_space *mapping = super->s_mapping_inode->i_mapping; + u64 ofs; + pgoff_t index; + int page_ofs; + struct page *page; + + ofs = dev_ofs(sb, area->a_segno, + area->a_used_bytes & ~(super->s_writesize - 1)); + index = ofs >> PAGE_SHIFT; + page_ofs = ofs & (PAGE_SIZE - 1); + + page = find_lock_page(mapping, index); + BUG_ON(!page); + memcpy(wbuf, page_address(page) + page_ofs, super->s_writesize); + unlock_page(page); +} + +static void *logfs_write_area(struct super_block *sb, void *_a, + u16 *type, size_t *len) +{ + struct logfs_super *super = logfs_super(sb); + struct logfs_area *area = super->s_area[super->s_sum_index]; + struct logfs_je_area *a = _a; + + a->vim = VIM_DEFAULT; + a->gc_level = super->s_sum_index; + a->used_bytes = cpu_to_be32(area->a_used_bytes); + a->segno = cpu_to_be32(area->a_segno); + if (super->s_writesize > 1) + write_wbuf(sb, area, a + 1); + + *type = JE_AREA; + *len = sizeof(*a) + super->s_writesize; + return a; +} + +static void *logfs_write_commit(struct super_block *sb, void *h, + u16 *type, size_t *len) +{ + struct logfs_super *super = logfs_super(sb); + + *type = JE_COMMIT; + *len = super->s_no_je * sizeof(__be64); + return super->s_je_array; +} + +static size_t __logfs_write_je(struct super_block *sb, void *buf, u16 type, + size_t len) +{ + struct logfs_super *super = logfs_super(sb); + void *header = super->s_compressed_je; + void *data = header + sizeof(struct logfs_journal_header); + ssize_t compr_len, pad_len; + u8 compr = COMPR_ZLIB; + + if (len == 0) + return logfs_write_header(super, header, 0, type); + + compr_len = logfs_compress(buf, data, len, sb->s_blocksize); + if (compr_len < 0 || type == JE_ANCHOR) { + BUG_ON(len > sb->s_blocksize); + memcpy(data, buf, len); + compr_len = len; + compr = COMPR_NONE; + } + + pad_len = ALIGN(compr_len, 16); + memset(data + compr_len, 0, pad_len - compr_len); + + return __logfs_write_header(super, header, compr_len, len, type, compr); +} + +static s64 logfs_get_free_bytes(struct logfs_area *area, size_t *bytes, + int must_pad) +{ + u32 writesize = logfs_super(area->a_sb)->s_writesize; + s32 ofs; + int ret; + + ret = logfs_open_area(area, *bytes); + if (ret) + return -EAGAIN; + + ofs = area->a_used_bytes; + area->a_used_bytes += *bytes; + + if (must_pad) { + area->a_used_bytes = ALIGN(area->a_used_bytes, writesize); + *bytes = area->a_used_bytes - ofs; + } + + return dev_ofs(area->a_sb, area->a_segno, ofs); +} + +static int logfs_write_je_buf(struct super_block *sb, void *buf, u16 type, + size_t buf_len) +{ + struct logfs_super *super = logfs_super(sb); + struct logfs_area *area = super->s_journal_area; + struct logfs_journal_header *jh = super->s_compressed_je; + size_t len; + int must_pad = 0; + s64 ofs; + + len = __logfs_write_je(sb, buf, type, buf_len); + if (jh->h_type == cpu_to_be16(JE_COMMIT)) + must_pad = 1; + + ofs = logfs_get_free_bytes(area, &len, must_pad); + if (ofs < 0) + return ofs; + logfs_buf_write(area, ofs, super->s_compressed_je, len); + super->s_je_array[super->s_no_je++] = cpu_to_be64(ofs); + return 0; +} + +static int logfs_write_je(struct super_block *sb, + void* (*write)(struct super_block *sb, void *scratch, + u16 *type, size_t *len)) +{ + void *buf; + size_t len; + u16 type; + + buf = write(sb, logfs_super(sb)->s_je, &type, &len); + return logfs_write_je_buf(sb, buf, type, len); +} + +int write_alias_journal(struct super_block *sb, u64 ino, u64 bix, + level_t level, int child_no, __be64 val) +{ + struct logfs_super *super = logfs_super(sb); + struct logfs_obj_alias *oa = super->s_je; + int err = 0, fill = super->s_je_fill; + + log_aliases("logfs_write_obj_aliases #%x(%llx, %llx, %x, %x) %llx\n", + fill, ino, bix, level, child_no, be64_to_cpu(val)); + oa[fill].ino = cpu_to_be64(ino); + oa[fill].bix = cpu_to_be64(bix); + oa[fill].val = val; + oa[fill].level = (__force u8)level; + oa[fill].child_no = cpu_to_be16(child_no); + fill++; + if (fill >= sb->s_blocksize / sizeof(*oa)) { + err = logfs_write_je_buf(sb, oa, JE_OBJ_ALIAS, sb->s_blocksize); + fill = 0; + } + + super->s_je_fill = fill; + return err; +} + +static int logfs_write_obj_aliases(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + int err; + + log_journal("logfs_write_obj_aliases: %d aliases to write\n", + super->s_no_object_aliases); + super->s_je_fill = 0; + err = logfs_write_obj_aliases_pagecache(sb); + if (err) + return err; + + if (super->s_je_fill) + err = logfs_write_je_buf(sb, super->s_je, JE_OBJ_ALIAS, + super->s_je_fill + * sizeof(struct logfs_obj_alias)); + return err; +} + +/* + * Write all journal entries. The goto logic ensures that all journal entries + * are written whenever a new segment is used. It is ugly and potentially a + * bit wasteful, but robustness is more important. With this we can *always* + * erase all journal segments except the one containing the most recent commit. + */ +void logfs_write_anchor(struct inode *inode) +{ + struct super_block *sb = inode->i_sb; + struct logfs_super *super = logfs_super(sb); + struct logfs_area *area = super->s_journal_area; + int i, err; + + BUG_ON(logfs_super(sb)->s_flags & LOGFS_SB_FLAG_SHUTDOWN); + mutex_lock(&super->s_journal_mutex); + + /* Do this first or suffer corruption */ + logfs_sync_segments(sb); + account_shadows(sb); + +again: + super->s_no_je = 0; + for_each_area(i) { + if (!super->s_area[i]->a_is_open) + continue; + super->s_sum_index = i; + err = logfs_write_je(sb, logfs_write_area); + if (err) + goto again; + } + err = logfs_write_obj_aliases(sb); + if (err) + goto again; + err = logfs_write_je(sb, logfs_write_erasecount); + if (err) + goto again; + err = logfs_write_je(sb, __logfs_write_anchor); + if (err) + goto again; + err = logfs_write_je(sb, logfs_write_dynsb); + if (err) + goto again; + /* + * Order is imperative. First we sync all writes, including the + * non-committed journal writes. Then we write the final commit and + * sync the current journal segment. + * There is a theoretical bug here. Syncing the journal segment will + * write a number of journal entries and the final commit. All these + * are written in a single operation. If the device layer writes the + * data back-to-front, the commit will precede the other journal + * entries, leaving a race window. + * Two fixes are possible. Preferred is to fix the device layer to + * ensure writes happen front-to-back. Alternatively we can insert + * another logfs_sync_area() super->s_devops->sync() combo before + * writing the commit. + */ + /* + * On another subject, super->s_devops->sync is usually not necessary. + * Unless called from sys_sync or friends, a barrier would suffice. + */ + super->s_devops->sync(sb); + err = logfs_write_je(sb, logfs_write_commit); + if (err) + goto again; + log_journal("Write commit to %llx\n", + be64_to_cpu(super->s_je_array[super->s_no_je - 1])); + logfs_sync_area(area); + BUG_ON(area->a_used_bytes != area->a_written_bytes); + super->s_devops->sync(sb); + + mutex_unlock(&super->s_journal_mutex); + return; +} + +void do_logfs_journal_wl_pass(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + struct logfs_area *area = super->s_journal_area; + u32 segno, ec; + int i, err; + + log_journal("Journal requires wear-leveling.\n"); + /* Drop old segments */ + journal_for_each(i) + if (super->s_journal_seg[i]) { + logfs_set_segment_unreserved(sb, + super->s_journal_seg[i], + super->s_journal_ec[i]); + super->s_journal_seg[i] = 0; + super->s_journal_ec[i] = 0; + } + /* Get new segments */ + for (i = 0; i < super->s_no_journal_segs; i++) { + segno = get_best_cand(sb, &super->s_reserve_list, &ec); + super->s_journal_seg[i] = segno; + super->s_journal_ec[i] = ec; + logfs_set_segment_reserved(sb, segno); + } + /* Manually move journal_area */ + area->a_segno = super->s_journal_seg[0]; + area->a_is_open = 0; + area->a_used_bytes = 0; + /* Write journal */ + logfs_write_anchor(super->s_master_inode); + /* Write superblocks */ + err = logfs_write_sb(sb); + BUG_ON(err); +} + +static const struct logfs_area_ops journal_area_ops = { + .get_free_segment = journal_get_free_segment, + .get_erase_count = journal_get_erase_count, + .erase_segment = journal_erase_segment, +}; + +int logfs_init_journal(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + size_t bufsize = max_t(size_t, sb->s_blocksize, super->s_writesize) + + MAX_JOURNAL_HEADER; + int ret = -ENOMEM; + + mutex_init(&super->s_journal_mutex); + btree_init_mempool32(&super->s_reserved_segments, super->s_btree_pool); + + super->s_je = kzalloc(bufsize, GFP_KERNEL); + if (!super->s_je) + return ret; + + super->s_compressed_je = kzalloc(bufsize, GFP_KERNEL); + if (!super->s_compressed_je) + return ret; + + super->s_master_inode = logfs_new_meta_inode(sb, LOGFS_INO_MASTER); + if (IS_ERR(super->s_master_inode)) + return PTR_ERR(super->s_master_inode); + + ret = logfs_read_journal(sb); + if (ret) + return -EIO; + + reserve_sb_and_journal(sb); + logfs_calc_free(sb); + + super->s_journal_area->a_ops = &journal_area_ops; + return 0; +} + +void logfs_cleanup_journal(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + + btree_grim_visitor32(&super->s_reserved_segments, 0, NULL); + destroy_meta_inode(super->s_master_inode); + super->s_master_inode = NULL; + + kfree(super->s_compressed_je); + kfree(super->s_je); +} diff --git a/fs/logfs/logfs.h b/fs/logfs/logfs.h new file mode 100644 index 00000000000..e3082abe9e3 --- /dev/null +++ b/fs/logfs/logfs.h @@ -0,0 +1,722 @@ +/* + * fs/logfs/logfs.h + * + * As should be obvious for Linux kernel code, license is GPLv2 + * + * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org> + * + * Private header for logfs. + */ +#ifndef FS_LOGFS_LOGFS_H +#define FS_LOGFS_LOGFS_H + +#undef __CHECK_ENDIAN__ +#define __CHECK_ENDIAN__ + +#include <linux/btree.h> +#include <linux/crc32.h> +#include <linux/fs.h> +#include <linux/kernel.h> +#include <linux/mempool.h> +#include <linux/pagemap.h> +#include <linux/mtd/mtd.h> +#include "logfs_abi.h" + +#define LOGFS_DEBUG_SUPER (0x0001) +#define LOGFS_DEBUG_SEGMENT (0x0002) +#define LOGFS_DEBUG_JOURNAL (0x0004) +#define LOGFS_DEBUG_DIR (0x0008) +#define LOGFS_DEBUG_FILE (0x0010) +#define LOGFS_DEBUG_INODE (0x0020) +#define LOGFS_DEBUG_READWRITE (0x0040) +#define LOGFS_DEBUG_GC (0x0080) +#define LOGFS_DEBUG_GC_NOISY (0x0100) +#define LOGFS_DEBUG_ALIASES (0x0200) +#define LOGFS_DEBUG_BLOCKMOVE (0x0400) +#define LOGFS_DEBUG_ALL (0xffffffff) + +#define LOGFS_DEBUG (0x01) +/* + * To enable specific log messages, simply define LOGFS_DEBUG to match any + * or all of the above. + */ +#ifndef LOGFS_DEBUG +#define LOGFS_DEBUG (0) +#endif + +#define log_cond(cond, fmt, arg...) do { \ + if (cond) \ + printk(KERN_DEBUG fmt, ##arg); \ +} while (0) + +#define log_super(fmt, arg...) \ + log_cond(LOGFS_DEBUG & LOGFS_DEBUG_SUPER, fmt, ##arg) +#define log_segment(fmt, arg...) \ + log_cond(LOGFS_DEBUG & LOGFS_DEBUG_SEGMENT, fmt, ##arg) +#define log_journal(fmt, arg...) \ + log_cond(LOGFS_DEBUG & LOGFS_DEBUG_JOURNAL, fmt, ##arg) +#define log_dir(fmt, arg...) \ + log_cond(LOGFS_DEBUG & LOGFS_DEBUG_DIR, fmt, ##arg) +#define log_file(fmt, arg...) \ + log_cond(LOGFS_DEBUG & LOGFS_DEBUG_FILE, fmt, ##arg) +#define log_inode(fmt, arg...) \ + log_cond(LOGFS_DEBUG & LOGFS_DEBUG_INODE, fmt, ##arg) +#define log_readwrite(fmt, arg...) \ + log_cond(LOGFS_DEBUG & LOGFS_DEBUG_READWRITE, fmt, ##arg) +#define log_gc(fmt, arg...) \ + log_cond(LOGFS_DEBUG & LOGFS_DEBUG_GC, fmt, ##arg) +#define log_gc_noisy(fmt, arg...) \ + log_cond(LOGFS_DEBUG & LOGFS_DEBUG_GC_NOISY, fmt, ##arg) +#define log_aliases(fmt, arg...) \ + log_cond(LOGFS_DEBUG & LOGFS_DEBUG_ALIASES, fmt, ##arg) +#define log_blockmove(fmt, arg...) \ + log_cond(LOGFS_DEBUG & LOGFS_DEBUG_BLOCKMOVE, fmt, ##arg) + +#define PG_pre_locked PG_owner_priv_1 +#define PagePreLocked(page) test_bit(PG_pre_locked, &(page)->flags) +#define SetPagePreLocked(page) set_bit(PG_pre_locked, &(page)->flags) +#define ClearPagePreLocked(page) clear_bit(PG_pre_locked, &(page)->flags) + +/* FIXME: This should really be somewhere in the 64bit area. */ +#define LOGFS_LINK_MAX (1<<30) + +/* Read-only filesystem */ +#define LOGFS_SB_FLAG_RO 0x0001 +#define LOGFS_SB_FLAG_SEG_ALIAS 0x0002 +#define LOGFS_SB_FLAG_OBJ_ALIAS 0x0004 +#define LOGFS_SB_FLAG_SHUTDOWN 0x0008 + +/* Write Control Flags */ +#define WF_LOCK 0x01 /* take write lock */ +#define WF_WRITE 0x02 /* write block */ +#define WF_DELETE 0x04 /* delete old block */ + +typedef u8 __bitwise level_t; +typedef u8 __bitwise gc_level_t; + +#define LEVEL(level) ((__force level_t)(level)) +#define GC_LEVEL(gc_level) ((__force gc_level_t)(gc_level)) + +#define SUBLEVEL(level) ( (void)((level) == LEVEL(1)), \ + (__force level_t)((__force u8)(level) - 1) ) + +/** + * struct logfs_area - area management information + * + * @a_sb: the superblock this area belongs to + * @a_is_open: 1 if the area is currently open, else 0 + * @a_segno: segment number of area + * @a_written_bytes: number of bytes already written back + * @a_used_bytes: number of used bytes + * @a_ops: area operations (either journal or ostore) + * @a_erase_count: erase count + * @a_level: GC level + */ +struct logfs_area { /* a segment open for writing */ + struct super_block *a_sb; + int a_is_open; + u32 a_segno; + u32 a_written_bytes; + u32 a_used_bytes; + const struct logfs_area_ops *a_ops; + u32 a_erase_count; + gc_level_t a_level; +}; + +/** + * struct logfs_area_ops - area operations + * + * @get_free_segment: fill area->ofs with the offset of a free segment + * @get_erase_count: fill area->erase_count (needs area->ofs) + * @erase_segment: erase and setup segment + */ +struct logfs_area_ops { + void (*get_free_segment)(struct logfs_area *area); + void (*get_erase_count)(struct logfs_area *area); + int (*erase_segment)(struct logfs_area *area); +}; + +/** + * struct logfs_device_ops - device access operations + * + * @readpage: read one page (mm page) + * @writeseg: write one segment. may be a partial segment + * @erase: erase one segment + * @read: read from the device + * @erase: erase part of the device + */ +struct logfs_device_ops { + struct page *(*find_first_sb)(struct super_block *sb, u64 *ofs); + struct page *(*find_last_sb)(struct super_block *sb, u64 *ofs); + int (*write_sb)(struct super_block *sb, struct page *page); + int (*readpage)(void *_sb, struct page *page); + void (*writeseg)(struct super_block *sb, u64 ofs, size_t len); + int (*erase)(struct super_block *sb, loff_t ofs, size_t len); + void (*sync)(struct super_block *sb); + void (*put_device)(struct super_block *sb); +}; + +/** + * struct candidate_list - list of similar candidates + */ +struct candidate_list { + struct rb_root rb_tree; + int count; + int maxcount; + int sort_by_ec; +}; + +/** + * struct gc_candidate - "candidate" segment to be garbage collected next + * + * @list: list (either free of low) + * @segno: segment number + * @valid: number of valid bytes + * @erase_count: erase count of segment + * @dist: distance from tree root + * + * Candidates can be on two lists. The free list contains electees rather + * than candidates - segments that no longer contain any valid data. The + * low list contains candidates to be picked for GC. It should be kept + * short. It is not required to always pick a perfect candidate. In the + * worst case GC will have to move more data than absolutely necessary. + */ +struct gc_candidate { + struct rb_node rb_node; + struct candidate_list *list; + u32 segno; + u32 valid; + u32 erase_count; + u8 dist; +}; + +/** + * struct logfs_journal_entry - temporary structure used during journal scan + * + * @used: + * @version: normalized version + * @len: length + * @offset: offset + */ +struct logfs_journal_entry { + int used; + s16 version; + u16 len; + u16 datalen; + u64 offset; +}; + +enum transaction_state { + CREATE_1 = 1, + CREATE_2, + UNLINK_1, + UNLINK_2, + CROSS_RENAME_1, + CROSS_RENAME_2, + TARGET_RENAME_1, + TARGET_RENAME_2, + TARGET_RENAME_3 +}; + +/** + * struct logfs_transaction - essential fields to support atomic dirops + * + * @ino: target inode + * @dir: inode of directory containing dentry + * @pos: pos of dentry in directory + */ +struct logfs_transaction { + enum transaction_state state; + u64 ino; + u64 dir; + u64 pos; +}; + +/** + * struct logfs_shadow - old block in the shadow of a not-yet-committed new one + * @old_ofs: offset of old block on medium + * @new_ofs: offset of new block on medium + * @ino: inode number + * @bix: block index + * @old_len: size of old block, including header + * @new_len: size of new block, including header + * @level: block level + */ +struct logfs_shadow { + u64 old_ofs; + u64 new_ofs; + u64 ino; + u64 bix; + int old_len; + int new_len; + gc_level_t gc_level; +}; + +/** + * struct shadow_tree + * @new: shadows where old_ofs==0, indexed by new_ofs + * @old: shadows where old_ofs!=0, indexed by old_ofs + */ +struct shadow_tree { + struct btree_head64 new; + struct btree_head64 old; +}; + +struct object_alias_item { + struct list_head list; + __be64 val; + int child_no; +}; + +/** + * struct logfs_block - contains any block state + * @type: indirect block or inode + * @full: number of fully populated children + * @partial: number of partially populated children + * + * Most blocks are directly represented by page cache pages. But when a block + * becomes dirty, is part of a transaction, contains aliases or is otherwise + * special, a struct logfs_block is allocated to track the additional state. + * Inodes are very similar to indirect blocks, so they can also get one of + * these structures added when appropriate. + */ +#define BLOCK_INDIRECT 1 /* Indirect block */ +#define BLOCK_INODE 2 /* Inode */ +struct logfs_block_ops; +struct logfs_block { + struct list_head alias_list; + struct list_head item_list; + struct super_block *sb; + u64 ino; + u64 bix; + level_t level; + struct page *page; + struct inode *inode; + struct logfs_transaction *ta; + unsigned long alias_map[LOGFS_BLOCK_FACTOR / BITS_PER_LONG]; + struct logfs_block_ops *ops; + int full; + int partial; + int reserved_bytes; +}; + +typedef int write_alias_t(struct super_block *sb, u64 ino, u64 bix, + level_t level, int child_no, __be64 val); +struct logfs_block_ops { + void (*write_block)(struct logfs_block *block); + gc_level_t (*block_level)(struct logfs_block *block); + void (*free_block)(struct super_block *sb, struct logfs_block*block); + int (*write_alias)(struct super_block *sb, + struct logfs_block *block, + write_alias_t *write_one_alias); +}; + +struct logfs_super { + struct mtd_info *s_mtd; /* underlying device */ + struct block_device *s_bdev; /* underlying device */ + const struct logfs_device_ops *s_devops;/* device access */ + struct inode *s_master_inode; /* inode file */ + struct inode *s_segfile_inode; /* segment file */ + struct inode *s_mapping_inode; /* device mapping */ + atomic_t s_pending_writes; /* outstanting bios */ + long s_flags; + mempool_t *s_btree_pool; /* for btree nodes */ + mempool_t *s_alias_pool; /* aliases in segment.c */ + u64 s_feature_incompat; + u64 s_feature_ro_compat; + u64 s_feature_compat; + u64 s_feature_flags; + u64 s_sb_ofs[2]; + /* alias.c fields */ + struct btree_head32 s_segment_alias; /* remapped segments */ + int s_no_object_aliases; + struct list_head s_object_alias; /* remapped objects */ + struct btree_head128 s_object_alias_tree; /* remapped objects */ + struct mutex s_object_alias_mutex; + /* dir.c fields */ + struct mutex s_dirop_mutex; /* for creat/unlink/rename */ + u64 s_victim_ino; /* used for atomic dir-ops */ + u64 s_rename_dir; /* source directory ino */ + u64 s_rename_pos; /* position of source dd */ + /* gc.c fields */ + long s_segsize; /* size of a segment */ + int s_segshift; /* log2 of segment size */ + long s_segmask; /* 1 << s_segshift - 1 */ + long s_no_segs; /* segments on device */ + long s_no_journal_segs; /* segments used for journal */ + long s_no_blocks; /* blocks per segment */ + long s_writesize; /* minimum write size */ + int s_writeshift; /* log2 of write size */ + u64 s_size; /* filesystem size */ + struct logfs_area *s_area[LOGFS_NO_AREAS]; /* open segment array */ + u64 s_gec; /* global erase count */ + u64 s_wl_gec_ostore; /* time of last wl event */ + u64 s_wl_gec_journal; /* time of last wl event */ + u64 s_sweeper; /* current sweeper pos */ + u8 s_ifile_levels; /* max level of ifile */ + u8 s_iblock_levels; /* max level of regular files */ + u8 s_data_levels; /* # of segments to leaf block*/ + u8 s_total_levels; /* sum of above three */ + struct btree_head32 s_cand_tree; /* all candidates */ + struct candidate_list s_free_list; /* 100% free segments */ + struct candidate_list s_reserve_list; /* Bad segment reserve */ + struct candidate_list s_low_list[LOGFS_NO_AREAS];/* good candidates */ + struct candidate_list s_ec_list; /* wear level candidates */ + struct btree_head32 s_reserved_segments;/* sb, journal, bad, etc. */ + /* inode.c fields */ + u64 s_last_ino; /* highest ino used */ + long s_inos_till_wrap; + u32 s_generation; /* i_generation for new files */ + struct list_head s_freeing_list; /* inodes being freed */ + /* journal.c fields */ + struct mutex s_journal_mutex; + void *s_je; /* journal entry to compress */ + void *s_compressed_je; /* block to write to journal */ + u32 s_journal_seg[LOGFS_JOURNAL_SEGS]; /* journal segments */ + u32 s_journal_ec[LOGFS_JOURNAL_SEGS]; /* journal erasecounts */ + u64 s_last_version; + struct logfs_area *s_journal_area; /* open journal segment */ + __be64 s_je_array[64]; + int s_no_je; + + int s_sum_index; /* for the 12 summaries */ + struct shadow_tree s_shadow_tree; + int s_je_fill; /* index of current je */ + /* readwrite.c fields */ + struct mutex s_write_mutex; + int s_lock_count; + mempool_t *s_block_pool; /* struct logfs_block pool */ + mempool_t *s_shadow_pool; /* struct logfs_shadow pool */ + /* + * Space accounting: + * - s_used_bytes specifies space used to store valid data objects. + * - s_dirty_used_bytes is space used to store non-committed data + * objects. Those objects have already been written themselves, + * but they don't become valid until all indirect blocks up to the + * journal have been written as well. + * - s_dirty_free_bytes is space used to store the old copy of a + * replaced object, as long as the replacement is non-committed. + * In other words, it is the amount of space freed when all dirty + * blocks are written back. + * - s_free_bytes is the amount of free space available for any + * purpose. + * - s_root_reserve is the amount of free space available only to + * the root user. Non-privileged users can no longer write once + * this watermark has been reached. + * - s_speed_reserve is space which remains unused to speed up + * garbage collection performance. + * - s_dirty_pages is the space reserved for currently dirty pages. + * It is a pessimistic estimate, so some/most will get freed on + * page writeback. + * + * s_used_bytes + s_free_bytes + s_speed_reserve = total usable size + */ + u64 s_free_bytes; + u64 s_used_bytes; + u64 s_dirty_free_bytes; + u64 s_dirty_used_bytes; + u64 s_root_reserve; + u64 s_speed_reserve; + u64 s_dirty_pages; + /* Bad block handling: + * - s_bad_seg_reserve is a number of segments usually kept + * free. When encountering bad blocks, the affected segment's data + * is _temporarily_ moved to a reserved segment. + * - s_bad_segments is the number of known bad segments. + */ + u32 s_bad_seg_reserve; + u32 s_bad_segments; +}; + +/** + * struct logfs_inode - in-memory inode + * + * @vfs_inode: struct inode + * @li_data: data pointers + * @li_used_bytes: number of used bytes + * @li_freeing_list: used to track inodes currently being freed + * @li_flags: inode flags + * @li_refcount: number of internal (GC-induced) references + */ +struct logfs_inode { + struct inode vfs_inode; + u64 li_data[LOGFS_EMBEDDED_FIELDS]; + u64 li_used_bytes; + struct list_head li_freeing_list; + struct logfs_block *li_block; + u32 li_flags; + u8 li_height; + int li_refcount; +}; + +#define journal_for_each(__i) for (__i = 0; __i < LOGFS_JOURNAL_SEGS; __i++) +#define for_each_area(__i) for (__i = 0; __i < LOGFS_NO_AREAS; __i++) +#define for_each_area_down(__i) for (__i = LOGFS_NO_AREAS - 1; __i >= 0; __i--) + +/* compr.c */ +int logfs_compress(void *in, void *out, size_t inlen, size_t outlen); +int logfs_uncompress(void *in, void *out, size_t inlen, size_t outlen); +int __init logfs_compr_init(void); +void logfs_compr_exit(void); + +/* dev_bdev.c */ +#ifdef CONFIG_BLOCK +int logfs_get_sb_bdev(struct file_system_type *type, int flags, + const char *devname, struct vfsmount *mnt); +#else +static inline int logfs_get_sb_bdev(struct file_system_type *type, int flags, + const char *devname, struct vfsmount *mnt) +{ + return -ENODEV; +} +#endif + +/* dev_mtd.c */ +#ifdef CONFIG_MTD +int logfs_get_sb_mtd(struct file_system_type *type, int flags, + int mtdnr, struct vfsmount *mnt); +#else +static inline int logfs_get_sb_mtd(struct file_system_type *type, int flags, + int mtdnr, struct vfsmount *mnt) +{ + return -ENODEV; +} +#endif + +/* dir.c */ +extern const struct inode_operations logfs_symlink_iops; +extern const struct inode_operations logfs_dir_iops; +extern const struct file_operations logfs_dir_fops; +int logfs_replay_journal(struct super_block *sb); + +/* file.c */ +extern const struct inode_operations logfs_reg_iops; +extern const struct file_operations logfs_reg_fops; +extern const struct address_space_operations logfs_reg_aops; +int logfs_readpage(struct file *file, struct page *page); +int logfs_ioctl(struct inode *inode, struct file *file, unsigned int cmd, + unsigned long arg); +int logfs_fsync(struct file *file, struct dentry *dentry, int datasync); + +/* gc.c */ +u32 get_best_cand(struct super_block *sb, struct candidate_list *list, u32 *ec); +void logfs_gc_pass(struct super_block *sb); +int logfs_check_areas(struct super_block *sb); +int logfs_init_gc(struct super_block *sb); +void logfs_cleanup_gc(struct super_block *sb); + +/* inode.c */ +extern const struct super_operations logfs_super_operations; +struct inode *logfs_iget(struct super_block *sb, ino_t ino); +struct inode *logfs_safe_iget(struct super_block *sb, ino_t ino, int *cookie); +void logfs_safe_iput(struct inode *inode, int cookie); +struct inode *logfs_new_inode(struct inode *dir, int mode); +struct inode *logfs_new_meta_inode(struct super_block *sb, u64 ino); +struct inode *logfs_read_meta_inode(struct super_block *sb, u64 ino); +int logfs_init_inode_cache(void); +void logfs_destroy_inode_cache(void); +void destroy_meta_inode(struct inode *inode); +void logfs_set_blocks(struct inode *inode, u64 no); +/* these logically belong into inode.c but actually reside in readwrite.c */ +int logfs_read_inode(struct inode *inode); +int __logfs_write_inode(struct inode *inode, long flags); +void logfs_delete_inode(struct inode *inode); +void logfs_clear_inode(struct inode *inode); + +/* journal.c */ +void logfs_write_anchor(struct inode *inode); +int logfs_init_journal(struct super_block *sb); +void logfs_cleanup_journal(struct super_block *sb); +int write_alias_journal(struct super_block *sb, u64 ino, u64 bix, + level_t level, int child_no, __be64 val); +void do_logfs_journal_wl_pass(struct super_block *sb); + +/* readwrite.c */ +pgoff_t logfs_pack_index(u64 bix, level_t level); +void logfs_unpack_index(pgoff_t index, u64 *bix, level_t *level); +int logfs_inode_write(struct inode *inode, const void *buf, size_t count, + loff_t bix, long flags, struct shadow_tree *shadow_tree); +int logfs_readpage_nolock(struct page *page); +int logfs_write_buf(struct inode *inode, struct page *page, long flags); +int logfs_delete(struct inode *inode, pgoff_t index, + struct shadow_tree *shadow_tree); +int logfs_rewrite_block(struct inode *inode, u64 bix, u64 ofs, + gc_level_t gc_level, long flags); +int logfs_is_valid_block(struct super_block *sb, u64 ofs, u64 ino, u64 bix, + gc_level_t gc_level); +int logfs_truncate(struct inode *inode, u64 size); +u64 logfs_seek_hole(struct inode *inode, u64 bix); +u64 logfs_seek_data(struct inode *inode, u64 bix); +int logfs_open_segfile(struct super_block *sb); +int logfs_init_rw(struct super_block *sb); +void logfs_cleanup_rw(struct super_block *sb); +void logfs_add_transaction(struct inode *inode, struct logfs_transaction *ta); +void logfs_del_transaction(struct inode *inode, struct logfs_transaction *ta); +void logfs_write_block(struct logfs_block *block, long flags); +int logfs_write_obj_aliases_pagecache(struct super_block *sb); +void logfs_get_segment_entry(struct super_block *sb, u32 segno, + struct logfs_segment_entry *se); +void logfs_set_segment_used(struct super_block *sb, u64 ofs, int increment); +void logfs_set_segment_erased(struct super_block *sb, u32 segno, u32 ec, + gc_level_t gc_level); +void logfs_set_segment_reserved(struct super_block *sb, u32 segno); +void logfs_set_segment_unreserved(struct super_block *sb, u32 segno, u32 ec); +struct logfs_block *__alloc_block(struct super_block *sb, + u64 ino, u64 bix, level_t level); +void __free_block(struct super_block *sb, struct logfs_block *block); +void btree_write_block(struct logfs_block *block); +void initialize_block_counters(struct page *page, struct logfs_block *block, + __be64 *array, int page_is_empty); +int logfs_exist_block(struct inode *inode, u64 bix); +int get_page_reserve(struct inode *inode, struct page *page); +extern struct logfs_block_ops indirect_block_ops; + +/* segment.c */ +int logfs_erase_segment(struct super_block *sb, u32 ofs); +int wbuf_read(struct super_block *sb, u64 ofs, size_t len, void *buf); +int logfs_segment_read(struct inode *inode, struct page *page, u64 ofs, u64 bix, + level_t level); +int logfs_segment_write(struct inode *inode, struct page *page, + struct logfs_shadow *shadow); +int logfs_segment_delete(struct inode *inode, struct logfs_shadow *shadow); +int logfs_load_object_aliases(struct super_block *sb, + struct logfs_obj_alias *oa, int count); +void move_page_to_btree(struct page *page); +int logfs_init_mapping(struct super_block *sb); +void logfs_sync_area(struct logfs_area *area); +void logfs_sync_segments(struct super_block *sb); + +/* area handling */ +int logfs_init_areas(struct super_block *sb); +void logfs_cleanup_areas(struct super_block *sb); +int logfs_open_area(struct logfs_area *area, size_t bytes); +void __logfs_buf_write(struct logfs_area *area, u64 ofs, void *buf, size_t len, + int use_filler); + +static inline void logfs_buf_write(struct logfs_area *area, u64 ofs, + void *buf, size_t len) +{ + __logfs_buf_write(area, ofs, buf, len, 0); +} + +static inline void logfs_buf_recover(struct logfs_area *area, u64 ofs, + void *buf, size_t len) +{ + __logfs_buf_write(area, ofs, buf, len, 1); +} + +/* super.c */ +struct page *emergency_read_begin(struct address_space *mapping, pgoff_t index); +void emergency_read_end(struct page *page); +void logfs_crash_dump(struct super_block *sb); +void *memchr_inv(const void *s, int c, size_t n); +int logfs_statfs(struct dentry *dentry, struct kstatfs *stats); +int logfs_get_sb_device(struct file_system_type *type, int flags, + struct mtd_info *mtd, struct block_device *bdev, + const struct logfs_device_ops *devops, struct vfsmount *mnt); +int logfs_check_ds(struct logfs_disk_super *ds); +int logfs_write_sb(struct super_block *sb); + +static inline struct logfs_super *logfs_super(struct super_block *sb) +{ + return sb->s_fs_info; +} + +static inline struct logfs_inode *logfs_inode(struct inode *inode) +{ + return container_of(inode, struct logfs_inode, vfs_inode); +} + +static inline void logfs_set_ro(struct super_block *sb) +{ + logfs_super(sb)->s_flags |= LOGFS_SB_FLAG_RO; +} + +#define LOGFS_BUG(sb) do { \ + struct super_block *__sb = sb; \ + logfs_crash_dump(__sb); \ + logfs_super(__sb)->s_flags |= LOGFS_SB_FLAG_RO; \ + BUG(); \ +} while (0) + +#define LOGFS_BUG_ON(condition, sb) \ + do { if (unlikely(condition)) LOGFS_BUG((sb)); } while (0) + +static inline __be32 logfs_crc32(void *data, size_t len, size_t skip) +{ + return cpu_to_be32(crc32(~0, data+skip, len-skip)); +} + +static inline u8 logfs_type(struct inode *inode) +{ + return (inode->i_mode >> 12) & 15; +} + +static inline pgoff_t logfs_index(struct super_block *sb, u64 pos) +{ + return pos >> sb->s_blocksize_bits; +} + +static inline u64 dev_ofs(struct super_block *sb, u32 segno, u32 ofs) +{ + return ((u64)segno << logfs_super(sb)->s_segshift) + ofs; +} + +static inline u32 seg_no(struct super_block *sb, u64 ofs) +{ + return ofs >> logfs_super(sb)->s_segshift; +} + +static inline u32 seg_ofs(struct super_block *sb, u64 ofs) +{ + return ofs & logfs_super(sb)->s_segmask; +} + +static inline u64 seg_align(struct super_block *sb, u64 ofs) +{ + return ofs & ~logfs_super(sb)->s_segmask; +} + +static inline struct logfs_block *logfs_block(struct page *page) +{ + return (void *)page->private; +} + +static inline level_t shrink_level(gc_level_t __level) +{ + u8 level = (__force u8)__level; + + if (level >= LOGFS_MAX_LEVELS) + level -= LOGFS_MAX_LEVELS; + return (__force level_t)level; +} + +static inline gc_level_t expand_level(u64 ino, level_t __level) +{ + u8 level = (__force u8)__level; + + if (ino == LOGFS_INO_MASTER) { + /* ifile has seperate areas */ + level += LOGFS_MAX_LEVELS; + } + return (__force gc_level_t)level; +} + +static inline int logfs_block_shift(struct super_block *sb, level_t level) +{ + level = shrink_level((__force gc_level_t)level); + return (__force int)level * (sb->s_blocksize_bits - 3); +} + +static inline u64 logfs_block_mask(struct super_block *sb, level_t level) +{ + return ~0ull << logfs_block_shift(sb, level); +} + +static inline struct logfs_area *get_area(struct super_block *sb, + gc_level_t gc_level) +{ + return logfs_super(sb)->s_area[(__force u8)gc_level]; +} + +#endif diff --git a/fs/logfs/logfs_abi.h b/fs/logfs/logfs_abi.h new file mode 100644 index 00000000000..5d3782ddecc --- /dev/null +++ b/fs/logfs/logfs_abi.h @@ -0,0 +1,627 @@ +/* + * fs/logfs/logfs_abi.h + * + * As should be obvious for Linux kernel code, license is GPLv2 + * + * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org> + * + * Public header for logfs. + */ +#ifndef FS_LOGFS_LOGFS_ABI_H +#define FS_LOGFS_LOGFS_ABI_H + +/* For out-of-kernel compiles */ +#ifndef BUILD_BUG_ON +#define BUILD_BUG_ON(condition) /**/ +#endif + +#define SIZE_CHECK(type, size) \ +static inline void check_##type(void) \ +{ \ + BUILD_BUG_ON(sizeof(struct type) != (size)); \ +} + +/* + * Throughout the logfs code, we're constantly dealing with blocks at + * various positions or offsets. To remove confusion, we stricly + * distinguish between a "position" - the logical position within a + * file and an "offset" - the physical location within the device. + * + * Any usage of the term offset for a logical location or position for + * a physical one is a bug and should get fixed. + */ + +/* + * Block are allocated in one of several segments depending on their + * level. The following levels are used: + * 0 - regular data block + * 1 - i1 indirect blocks + * 2 - i2 indirect blocks + * 3 - i3 indirect blocks + * 4 - i4 indirect blocks + * 5 - i5 indirect blocks + * 6 - ifile data blocks + * 7 - ifile i1 indirect blocks + * 8 - ifile i2 indirect blocks + * 9 - ifile i3 indirect blocks + * 10 - ifile i4 indirect blocks + * 11 - ifile i5 indirect blocks + * Potential levels to be used in the future: + * 12 - gc recycled blocks, long-lived data + * 13 - replacement blocks, short-lived data + * + * Levels 1-11 are necessary for robust gc operations and help seperate + * short-lived metadata from longer-lived file data. In the future, + * file data should get seperated into several segments based on simple + * heuristics. Old data recycled during gc operation is expected to be + * long-lived. New data is of uncertain life expectancy. New data + * used to replace older blocks in existing files is expected to be + * short-lived. + */ + + +/* Magic numbers. 64bit for superblock, 32bit for statfs f_type */ +#define LOGFS_MAGIC 0xb21f205ac97e8168ull +#define LOGFS_MAGIC_U32 0xc97e8168u + +/* + * Various blocksize related macros. Blocksize is currently fixed at 4KiB. + * Sooner or later that should become configurable and the macros replaced + * by something superblock-dependent. Pointers in indirect blocks are and + * will remain 64bit. + * + * LOGFS_BLOCKSIZE - self-explaining + * LOGFS_BLOCK_FACTOR - number of pointers per indirect block + * LOGFS_BLOCK_BITS - log2 of LOGFS_BLOCK_FACTOR, used for shifts + */ +#define LOGFS_BLOCKSIZE (4096ull) +#define LOGFS_BLOCK_FACTOR (LOGFS_BLOCKSIZE / sizeof(u64)) +#define LOGFS_BLOCK_BITS (9) + +/* + * Number of blocks at various levels of indirection. There are 16 direct + * block pointers plus a single indirect pointer. + */ +#define I0_BLOCKS (16) +#define I1_BLOCKS LOGFS_BLOCK_FACTOR +#define I2_BLOCKS (LOGFS_BLOCK_FACTOR * I1_BLOCKS) +#define I3_BLOCKS (LOGFS_BLOCK_FACTOR * I2_BLOCKS) +#define I4_BLOCKS (LOGFS_BLOCK_FACTOR * I3_BLOCKS) +#define I5_BLOCKS (LOGFS_BLOCK_FACTOR * I4_BLOCKS) + +#define INDIRECT_INDEX I0_BLOCKS +#define LOGFS_EMBEDDED_FIELDS (I0_BLOCKS + 1) + +/* + * Sizes at which files require another level of indirection. Files smaller + * than LOGFS_EMBEDDED_SIZE can be completely stored in the inode itself, + * similar like ext2 fast symlinks. + * + * Data at a position smaller than LOGFS_I0_SIZE is accessed through the + * direct pointers, else through the 1x indirect pointer and so forth. + */ +#define LOGFS_EMBEDDED_SIZE (LOGFS_EMBEDDED_FIELDS * sizeof(u64)) +#define LOGFS_I0_SIZE (I0_BLOCKS * LOGFS_BLOCKSIZE) +#define LOGFS_I1_SIZE (I1_BLOCKS * LOGFS_BLOCKSIZE) +#define LOGFS_I2_SIZE (I2_BLOCKS * LOGFS_BLOCKSIZE) +#define LOGFS_I3_SIZE (I3_BLOCKS * LOGFS_BLOCKSIZE) +#define LOGFS_I4_SIZE (I4_BLOCKS * LOGFS_BLOCKSIZE) +#define LOGFS_I5_SIZE (I5_BLOCKS * LOGFS_BLOCKSIZE) + +/* + * Each indirect block pointer must have this flag set, if all block pointers + * behind it are set, i.e. there is no hole hidden in the shadow of this + * indirect block pointer. + */ +#define LOGFS_FULLY_POPULATED (1ULL << 63) +#define pure_ofs(ofs) (ofs & ~LOGFS_FULLY_POPULATED) + +/* + * LogFS needs to seperate data into levels. Each level is defined as the + * maximal possible distance from the master inode (inode of the inode file). + * Data blocks reside on level 0, 1x indirect block on level 1, etc. + * Inodes reside on level 6, indirect blocks for the inode file on levels 7-11. + * This effort is necessary to guarantee garbage collection to always make + * progress. + * + * LOGFS_MAX_INDIRECT is the maximal indirection through indirect blocks, + * LOGFS_MAX_LEVELS is one more for the actual data level of a file. It is + * the maximal number of levels for one file. + * LOGFS_NO_AREAS is twice that, as the inode file and regular files are + * effectively stacked on top of each other. + */ +#define LOGFS_MAX_INDIRECT (5) +#define LOGFS_MAX_LEVELS (LOGFS_MAX_INDIRECT + 1) +#define LOGFS_NO_AREAS (2 * LOGFS_MAX_LEVELS) + +/* Maximum size of filenames */ +#define LOGFS_MAX_NAMELEN (255) + +/* Number of segments in the primary journal. */ +#define LOGFS_JOURNAL_SEGS (16) + +/* Maximum number of free/erased/etc. segments in journal entries */ +#define MAX_CACHED_SEGS (64) + + +/* + * LOGFS_OBJECT_HEADERSIZE is the size of a single header in the object store, + * LOGFS_MAX_OBJECTSIZE the size of the largest possible object, including + * its header, + * LOGFS_SEGMENT_RESERVE is the amount of space reserved for each segment for + * its segment header and the padded space at the end when no further objects + * fit. + */ +#define LOGFS_OBJECT_HEADERSIZE (0x1c) +#define LOGFS_SEGMENT_HEADERSIZE (0x18) +#define LOGFS_MAX_OBJECTSIZE (LOGFS_OBJECT_HEADERSIZE + LOGFS_BLOCKSIZE) +#define LOGFS_SEGMENT_RESERVE \ + (LOGFS_SEGMENT_HEADERSIZE + LOGFS_MAX_OBJECTSIZE - 1) + +/* + * Segment types: + * SEG_SUPER - Data or indirect block + * SEG_JOURNAL - Inode + * SEG_OSTORE - Dentry + */ +enum { + SEG_SUPER = 0x01, + SEG_JOURNAL = 0x02, + SEG_OSTORE = 0x03, +}; + +/** + * struct logfs_segment_header - per-segment header in the ostore + * + * @crc: crc32 of header (there is no data) + * @pad: unused, must be 0 + * @type: segment type, see above + * @level: GC level for all objects in this segment + * @segno: segment number + * @ec: erase count for this segment + * @gec: global erase count at time of writing + */ +struct logfs_segment_header { + __be32 crc; + __be16 pad; + __u8 type; + __u8 level; + __be32 segno; + __be32 ec; + __be64 gec; +}; + +SIZE_CHECK(logfs_segment_header, LOGFS_SEGMENT_HEADERSIZE); + +/** + * struct logfs_disk_super - on-medium superblock + * + * @ds_magic: magic number, must equal LOGFS_MAGIC + * @ds_crc: crc32 of structure starting with the next field + * @ds_ifile_levels: maximum number of levels for ifile + * @ds_iblock_levels: maximum number of levels for regular files + * @ds_data_levels: number of seperate levels for data + * @pad0: reserved, must be 0 + * @ds_feature_incompat: incompatible filesystem features + * @ds_feature_ro_compat: read-only compatible filesystem features + * @ds_feature_compat: compatible filesystem features + * @ds_flags: flags + * @ds_segment_shift: log2 of segment size + * @ds_block_shift: log2 of block size + * @ds_write_shift: log2 of write size + * @pad1: reserved, must be 0 + * @ds_journal_seg: segments used by primary journal + * @ds_root_reserve: bytes reserved for the superuser + * @ds_speed_reserve: bytes reserved to speed up GC + * @ds_bad_seg_reserve: number of segments reserved to handle bad blocks + * @pad2: reserved, must be 0 + * @pad3: reserved, must be 0 + * + * Contains only read-only fields. Read-write fields like the amount of used + * space is tracked in the dynamic superblock, which is stored in the journal. + */ +struct logfs_disk_super { + struct logfs_segment_header ds_sh; + __be64 ds_magic; + + __be32 ds_crc; + __u8 ds_ifile_levels; + __u8 ds_iblock_levels; + __u8 ds_data_levels; + __u8 ds_segment_shift; + __u8 ds_block_shift; + __u8 ds_write_shift; + __u8 pad0[6]; + + __be64 ds_filesystem_size; + __be32 ds_segment_size; + __be32 ds_bad_seg_reserve; + + __be64 ds_feature_incompat; + __be64 ds_feature_ro_compat; + + __be64 ds_feature_compat; + __be64 ds_feature_flags; + + __be64 ds_root_reserve; + __be64 ds_speed_reserve; + + __be32 ds_journal_seg[LOGFS_JOURNAL_SEGS]; + + __be64 ds_super_ofs[2]; + __be64 pad3[8]; +}; + +SIZE_CHECK(logfs_disk_super, 256); + +/* + * Object types: + * OBJ_BLOCK - Data or indirect block + * OBJ_INODE - Inode + * OBJ_DENTRY - Dentry + */ +enum { + OBJ_BLOCK = 0x04, + OBJ_INODE = 0x05, + OBJ_DENTRY = 0x06, +}; + +/** + * struct logfs_object_header - per-object header in the ostore + * + * @crc: crc32 of header, excluding data_crc + * @len: length of data + * @type: object type, see above + * @compr: compression type + * @ino: inode number + * @bix: block index + * @data_crc: crc32 of payload + */ +struct logfs_object_header { + __be32 crc; + __be16 len; + __u8 type; + __u8 compr; + __be64 ino; + __be64 bix; + __be32 data_crc; +} __attribute__((packed)); + +SIZE_CHECK(logfs_object_header, LOGFS_OBJECT_HEADERSIZE); + +/* + * Reserved inode numbers: + * LOGFS_INO_MASTER - master inode (for inode file) + * LOGFS_INO_ROOT - root directory + * LOGFS_INO_SEGFILE - per-segment used bytes and erase count + */ +enum { + LOGFS_INO_MAPPING = 0x00, + LOGFS_INO_MASTER = 0x01, + LOGFS_INO_ROOT = 0x02, + LOGFS_INO_SEGFILE = 0x03, + LOGFS_RESERVED_INOS = 0x10, +}; + +/* + * Inode flags. High bits should never be written to the medium. They are + * reserved for in-memory usage. + * Low bits should either remain in sync with the corresponding FS_*_FL or + * reuse slots that obviously don't make sense for logfs. + * + * LOGFS_IF_DIRTY Inode must be written back + * LOGFS_IF_ZOMBIE Inode has been deleted + * LOGFS_IF_STILLBORN -ENOSPC happened when creating inode + */ +#define LOGFS_IF_COMPRESSED 0x00000004 /* == FS_COMPR_FL */ +#define LOGFS_IF_DIRTY 0x20000000 +#define LOGFS_IF_ZOMBIE 0x40000000 +#define LOGFS_IF_STILLBORN 0x80000000 + +/* Flags available to chattr */ +#define LOGFS_FL_USER_VISIBLE (LOGFS_IF_COMPRESSED) +#define LOGFS_FL_USER_MODIFIABLE (LOGFS_IF_COMPRESSED) +/* Flags inherited from parent directory on file/directory creation */ +#define LOGFS_FL_INHERITED (LOGFS_IF_COMPRESSED) + +/** + * struct logfs_disk_inode - on-medium inode + * + * @di_mode: file mode + * @di_pad: reserved, must be 0 + * @di_flags: inode flags, see above + * @di_uid: user id + * @di_gid: group id + * @di_ctime: change time + * @di_mtime: modify time + * @di_refcount: reference count (aka nlink or link count) + * @di_generation: inode generation, for nfs + * @di_used_bytes: number of bytes used + * @di_size: file size + * @di_data: data pointers + */ +struct logfs_disk_inode { + __be16 di_mode; + __u8 di_height; + __u8 di_pad; + __be32 di_flags; + __be32 di_uid; + __be32 di_gid; + + __be64 di_ctime; + __be64 di_mtime; + + __be64 di_atime; + __be32 di_refcount; + __be32 di_generation; + + __be64 di_used_bytes; + __be64 di_size; + + __be64 di_data[LOGFS_EMBEDDED_FIELDS]; +}; + +SIZE_CHECK(logfs_disk_inode, 200); + +#define INODE_POINTER_OFS \ + (offsetof(struct logfs_disk_inode, di_data) / sizeof(__be64)) +#define INODE_USED_OFS \ + (offsetof(struct logfs_disk_inode, di_used_bytes) / sizeof(__be64)) +#define INODE_SIZE_OFS \ + (offsetof(struct logfs_disk_inode, di_size) / sizeof(__be64)) +#define INODE_HEIGHT_OFS (0) + +/** + * struct logfs_disk_dentry - on-medium dentry structure + * + * @ino: inode number + * @namelen: length of file name + * @type: file type, identical to bits 12..15 of mode + * @name: file name + */ +/* FIXME: add 6 bytes of padding to remove the __packed */ +struct logfs_disk_dentry { + __be64 ino; + __be16 namelen; + __u8 type; + __u8 name[LOGFS_MAX_NAMELEN]; +} __attribute__((packed)); + +SIZE_CHECK(logfs_disk_dentry, 266); + +#define RESERVED 0xffffffff +#define BADSEG 0xffffffff +/** + * struct logfs_segment_entry - segment file entry + * + * @ec_level: erase count and level + * @valid: number of valid bytes + * + * Segment file contains one entry for every segment. ec_level contains the + * erasecount in the upper 28 bits and the level in the lower 4 bits. An + * ec_level of BADSEG (-1) identifies bad segments. valid contains the number + * of valid bytes or RESERVED (-1 again) if the segment is used for either the + * superblock or the journal, or when the segment is bad. + */ +struct logfs_segment_entry { + __be32 ec_level; + __be32 valid; +}; + +SIZE_CHECK(logfs_segment_entry, 8); + +/** + * struct logfs_journal_header - header for journal entries (JEs) + * + * @h_crc: crc32 of journal entry + * @h_len: length of compressed journal entry, + * not including header + * @h_datalen: length of uncompressed data + * @h_type: JE type + * @h_version: unnormalized version of journal entry + * @h_compr: compression type + * @h_pad: reserved + */ +struct logfs_journal_header { + __be32 h_crc; + __be16 h_len; + __be16 h_datalen; + __be16 h_type; + __be16 h_version; + __u8 h_compr; + __u8 h_pad[3]; +}; + +SIZE_CHECK(logfs_journal_header, 16); + +/* + * Life expectency of data. + * VIM_DEFAULT - default vim + * VIM_SEGFILE - for segment file only - very short-living + * VIM_GC - GC'd data - likely long-living + */ +enum logfs_vim { + VIM_DEFAULT = 0, + VIM_SEGFILE = 1, +}; + +/** + * struct logfs_je_area - wbuf header + * + * @segno: segment number of area + * @used_bytes: number of bytes already used + * @gc_level: GC level + * @vim: life expectancy of data + * + * "Areas" are segments currently being used for writing. There is at least + * one area per GC level. Several may be used to seperate long-living from + * short-living data. If an area with unknown vim is encountered, it can + * simply be closed. + * The write buffer immediately follow this header. + */ +struct logfs_je_area { + __be32 segno; + __be32 used_bytes; + __u8 gc_level; + __u8 vim; +} __attribute__((packed)); + +SIZE_CHECK(logfs_je_area, 10); + +#define MAX_JOURNAL_HEADER \ + (sizeof(struct logfs_journal_header) + sizeof(struct logfs_je_area)) + +/** + * struct logfs_je_dynsb - dynamic superblock + * + * @ds_gec: global erase count + * @ds_sweeper: current position of GC "sweeper" + * @ds_rename_dir: source directory ino (see dir.c documentation) + * @ds_rename_pos: position of source dd (see dir.c documentation) + * @ds_victim_ino: victims of incomplete dir operation (see dir.c) + * @ds_victim_ino: parent inode of victim (see dir.c) + * @ds_used_bytes: number of used bytes + */ +struct logfs_je_dynsb { + __be64 ds_gec; + __be64 ds_sweeper; + + __be64 ds_rename_dir; + __be64 ds_rename_pos; + + __be64 ds_victim_ino; + __be64 ds_victim_parent; /* XXX */ + + __be64 ds_used_bytes; + __be32 ds_generation; + __be32 pad; +}; + +SIZE_CHECK(logfs_je_dynsb, 64); + +/** + * struct logfs_je_anchor - anchor of filesystem tree, aka master inode + * + * @da_size: size of inode file + * @da_last_ino: last created inode + * @da_used_bytes: number of bytes used + * @da_data: data pointers + */ +struct logfs_je_anchor { + __be64 da_size; + __be64 da_last_ino; + + __be64 da_used_bytes; + u8 da_height; + u8 pad[7]; + + __be64 da_data[LOGFS_EMBEDDED_FIELDS]; +}; + +SIZE_CHECK(logfs_je_anchor, 168); + +/** + * struct logfs_je_spillout - spillout entry (from 1st to 2nd journal) + * + * @so_segment: segments used for 2nd journal + * + * Length of the array is given by h_len field in the header. + */ +struct logfs_je_spillout { + __be64 so_segment[0]; +}; + +SIZE_CHECK(logfs_je_spillout, 0); + +/** + * struct logfs_je_journal_ec - erase counts for all journal segments + * + * @ec: erase count + * + * Length of the array is given by h_len field in the header. + */ +struct logfs_je_journal_ec { + __be32 ec[0]; +}; + +SIZE_CHECK(logfs_je_journal_ec, 0); + +/** + * struct logfs_je_free_segments - list of free segmetns with erase count + */ +struct logfs_je_free_segments { + __be32 segno; + __be32 ec; +}; + +SIZE_CHECK(logfs_je_free_segments, 8); + +/** + * struct logfs_seg_alias - list of segment aliases + */ +struct logfs_seg_alias { + __be32 old_segno; + __be32 new_segno; +}; + +SIZE_CHECK(logfs_seg_alias, 8); + +/** + * struct logfs_obj_alias - list of object aliases + */ +struct logfs_obj_alias { + __be64 ino; + __be64 bix; + __be64 val; + u8 level; + u8 pad[5]; + __be16 child_no; +}; + +SIZE_CHECK(logfs_obj_alias, 32); + +/** + * Compression types. + * + * COMPR_NONE - uncompressed + * COMPR_ZLIB - compressed with zlib + */ +enum { + COMPR_NONE = 0, + COMPR_ZLIB = 1, +}; + +/* + * Journal entries come in groups of 16. First group contains unique + * entries, next groups contain one entry per level + * + * JE_FIRST - smallest possible journal entry number + * + * JEG_BASE - base group, containing unique entries + * JE_COMMIT - commit entry, validates all previous entries + * JE_DYNSB - dynamic superblock, anything that ought to be in the + * superblock but cannot because it is read-write data + * JE_ANCHOR - anchor aka master inode aka inode file's inode + * JE_ERASECOUNT erasecounts for all journal segments + * JE_SPILLOUT - unused + * JE_SEG_ALIAS - aliases segments + * JE_AREA - area description + * + * JE_LAST - largest possible journal entry number + */ +enum { + JE_FIRST = 0x01, + + JEG_BASE = 0x00, + JE_COMMIT = 0x02, + JE_DYNSB = 0x03, + JE_ANCHOR = 0x04, + JE_ERASECOUNT = 0x05, + JE_SPILLOUT = 0x06, + JE_OBJ_ALIAS = 0x0d, + JE_AREA = 0x0e, + + JE_LAST = 0x0e, +}; + +#endif diff --git a/fs/logfs/readwrite.c b/fs/logfs/readwrite.c new file mode 100644 index 00000000000..1dbe6e8ccce --- /dev/null +++ b/fs/logfs/readwrite.c @@ -0,0 +1,2246 @@ +/* + * fs/logfs/readwrite.c + * + * As should be obvious for Linux kernel code, license is GPLv2 + * + * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org> + * + * + * Actually contains five sets of very similar functions: + * read read blocks from a file + * seek_hole find next hole + * seek_data find next data block + * valid check whether a block still belongs to a file + * write write blocks to a file + * delete delete a block (for directories and ifile) + * rewrite move existing blocks of a file to a new location (gc helper) + * truncate truncate a file + */ +#include "logfs.h" +#include <linux/sched.h> + +static u64 adjust_bix(u64 bix, level_t level) +{ + switch (level) { + case 0: + return bix; + case LEVEL(1): + return max_t(u64, bix, I0_BLOCKS); + case LEVEL(2): + return max_t(u64, bix, I1_BLOCKS); + case LEVEL(3): + return max_t(u64, bix, I2_BLOCKS); + case LEVEL(4): + return max_t(u64, bix, I3_BLOCKS); + case LEVEL(5): + return max_t(u64, bix, I4_BLOCKS); + default: + WARN_ON(1); + return bix; + } +} + +static inline u64 maxbix(u8 height) +{ + return 1ULL << (LOGFS_BLOCK_BITS * height); +} + +/** + * The inode address space is cut in two halves. Lower half belongs to data + * pages, upper half to indirect blocks. If the high bit (INDIRECT_BIT) is + * set, the actual block index (bix) and level can be derived from the page + * index. + * + * The lowest three bits of the block index are set to 0 after packing and + * unpacking. Since the lowest n bits (9 for 4KiB blocksize) are ignored + * anyway this is harmless. + */ +#define ARCH_SHIFT (BITS_PER_LONG - 32) +#define INDIRECT_BIT (0x80000000UL << ARCH_SHIFT) +#define LEVEL_SHIFT (28 + ARCH_SHIFT) +static inline pgoff_t first_indirect_block(void) +{ + return INDIRECT_BIT | (1ULL << LEVEL_SHIFT); +} + +pgoff_t logfs_pack_index(u64 bix, level_t level) +{ + pgoff_t index; + + BUG_ON(bix >= INDIRECT_BIT); + if (level == 0) + return bix; + + index = INDIRECT_BIT; + index |= (__force long)level << LEVEL_SHIFT; + index |= bix >> ((__force u8)level * LOGFS_BLOCK_BITS); + return index; +} + +void logfs_unpack_index(pgoff_t index, u64 *bix, level_t *level) +{ + u8 __level; + + if (!(index & INDIRECT_BIT)) { + *bix = index; + *level = 0; + return; + } + + __level = (index & ~INDIRECT_BIT) >> LEVEL_SHIFT; + *level = LEVEL(__level); + *bix = (index << (__level * LOGFS_BLOCK_BITS)) & ~INDIRECT_BIT; + *bix = adjust_bix(*bix, *level); + return; +} +#undef ARCH_SHIFT +#undef INDIRECT_BIT +#undef LEVEL_SHIFT + +/* + * Time is stored as nanoseconds since the epoch. + */ +static struct timespec be64_to_timespec(__be64 betime) +{ + return ns_to_timespec(be64_to_cpu(betime)); +} + +static __be64 timespec_to_be64(struct timespec tsp) +{ + return cpu_to_be64((u64)tsp.tv_sec * NSEC_PER_SEC + tsp.tv_nsec); +} + +static void logfs_disk_to_inode(struct logfs_disk_inode *di, struct inode*inode) +{ + struct logfs_inode *li = logfs_inode(inode); + int i; + + inode->i_mode = be16_to_cpu(di->di_mode); + li->li_height = di->di_height; + li->li_flags = be32_to_cpu(di->di_flags); + inode->i_uid = be32_to_cpu(di->di_uid); + inode->i_gid = be32_to_cpu(di->di_gid); + inode->i_size = be64_to_cpu(di->di_size); + logfs_set_blocks(inode, be64_to_cpu(di->di_used_bytes)); + inode->i_atime = be64_to_timespec(di->di_atime); + inode->i_ctime = be64_to_timespec(di->di_ctime); + inode->i_mtime = be64_to_timespec(di->di_mtime); + inode->i_nlink = be32_to_cpu(di->di_refcount); + inode->i_generation = be32_to_cpu(di->di_generation); + + switch (inode->i_mode & S_IFMT) { + case S_IFSOCK: /* fall through */ + case S_IFBLK: /* fall through */ + case S_IFCHR: /* fall through */ + case S_IFIFO: + inode->i_rdev = be64_to_cpu(di->di_data[0]); + break; + case S_IFDIR: /* fall through */ + case S_IFREG: /* fall through */ + case S_IFLNK: + for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++) + li->li_data[i] = be64_to_cpu(di->di_data[i]); + break; + default: + BUG(); + } +} + +static void logfs_inode_to_disk(struct inode *inode, struct logfs_disk_inode*di) +{ + struct logfs_inode *li = logfs_inode(inode); + int i; + + di->di_mode = cpu_to_be16(inode->i_mode); + di->di_height = li->li_height; + di->di_pad = 0; + di->di_flags = cpu_to_be32(li->li_flags); + di->di_uid = cpu_to_be32(inode->i_uid); + di->di_gid = cpu_to_be32(inode->i_gid); + di->di_size = cpu_to_be64(i_size_read(inode)); + di->di_used_bytes = cpu_to_be64(li->li_used_bytes); + di->di_atime = timespec_to_be64(inode->i_atime); + di->di_ctime = timespec_to_be64(inode->i_ctime); + di->di_mtime = timespec_to_be64(inode->i_mtime); + di->di_refcount = cpu_to_be32(inode->i_nlink); + di->di_generation = cpu_to_be32(inode->i_generation); + + switch (inode->i_mode & S_IFMT) { + case S_IFSOCK: /* fall through */ + case S_IFBLK: /* fall through */ + case S_IFCHR: /* fall through */ + case S_IFIFO: + di->di_data[0] = cpu_to_be64(inode->i_rdev); + break; + case S_IFDIR: /* fall through */ + case S_IFREG: /* fall through */ + case S_IFLNK: + for (i = 0; i < LOGFS_EMBEDDED_FIELDS; i++) + di->di_data[i] = cpu_to_be64(li->li_data[i]); + break; + default: + BUG(); + } +} + +static void __logfs_set_blocks(struct inode *inode) +{ + struct super_block *sb = inode->i_sb; + struct logfs_inode *li = logfs_inode(inode); + + inode->i_blocks = ULONG_MAX; + if (li->li_used_bytes >> sb->s_blocksize_bits < ULONG_MAX) + inode->i_blocks = ALIGN(li->li_used_bytes, 512) >> 9; +} + +void logfs_set_blocks(struct inode *inode, u64 bytes) +{ + struct logfs_inode *li = logfs_inode(inode); + + li->li_used_bytes = bytes; + __logfs_set_blocks(inode); +} + +static void prelock_page(struct super_block *sb, struct page *page, int lock) +{ + struct logfs_super *super = logfs_super(sb); + + BUG_ON(!PageLocked(page)); + if (lock) { + BUG_ON(PagePreLocked(page)); + SetPagePreLocked(page); + } else { + /* We are in GC path. */ + if (PagePreLocked(page)) + super->s_lock_count++; + else + SetPagePreLocked(page); + } +} + +static void preunlock_page(struct super_block *sb, struct page *page, int lock) +{ + struct logfs_super *super = logfs_super(sb); + + BUG_ON(!PageLocked(page)); + if (lock) + ClearPagePreLocked(page); + else { + /* We are in GC path. */ + BUG_ON(!PagePreLocked(page)); + if (super->s_lock_count) + super->s_lock_count--; + else + ClearPagePreLocked(page); + } +} + +/* + * Logfs is prone to an AB-BA deadlock where one task tries to acquire + * s_write_mutex with a locked page and GC tries to get that page while holding + * s_write_mutex. + * To solve this issue logfs will ignore the page lock iff the page in question + * is waiting for s_write_mutex. We annotate this fact by setting PG_pre_locked + * in addition to PG_locked. + */ +static void logfs_get_wblocks(struct super_block *sb, struct page *page, + int lock) +{ + struct logfs_super *super = logfs_super(sb); + + if (page) + prelock_page(sb, page, lock); + + if (lock) { + mutex_lock(&super->s_write_mutex); + logfs_gc_pass(sb); + /* FIXME: We also have to check for shadowed space + * and mempool fill grade */ + } +} + +static void logfs_put_wblocks(struct super_block *sb, struct page *page, + int lock) +{ + struct logfs_super *super = logfs_super(sb); + + if (page) + preunlock_page(sb, page, lock); + /* Order matters - we must clear PG_pre_locked before releasing + * s_write_mutex or we could race against another task. */ + if (lock) + mutex_unlock(&super->s_write_mutex); +} + +static struct page *logfs_get_read_page(struct inode *inode, u64 bix, + level_t level) +{ + return find_or_create_page(inode->i_mapping, + logfs_pack_index(bix, level), GFP_NOFS); +} + +static void logfs_put_read_page(struct page *page) +{ + unlock_page(page); + page_cache_release(page); +} + +static void logfs_lock_write_page(struct page *page) +{ + int loop = 0; + + while (unlikely(!trylock_page(page))) { + if (loop++ > 0x1000) { + /* Has been observed once so far... */ + printk(KERN_ERR "stack at %p\n", &loop); + BUG(); + } + if (PagePreLocked(page)) { + /* Holder of page lock is waiting for us, it + * is safe to use this page. */ + break; + } + /* Some other process has this page locked and has + * nothing to do with us. Wait for it to finish. + */ + schedule(); + } + BUG_ON(!PageLocked(page)); +} + +static struct page *logfs_get_write_page(struct inode *inode, u64 bix, + level_t level) +{ + struct address_space *mapping = inode->i_mapping; + pgoff_t index = logfs_pack_index(bix, level); + struct page *page; + int err; + +repeat: + page = find_get_page(mapping, index); + if (!page) { + page = __page_cache_alloc(GFP_NOFS); + if (!page) + return NULL; + err = add_to_page_cache_lru(page, mapping, index, GFP_NOFS); + if (unlikely(err)) { + page_cache_release(page); + if (err == -EEXIST) + goto repeat; + return NULL; + } + } else logfs_lock_write_page(page); + BUG_ON(!PageLocked(page)); + return page; +} + +static void logfs_unlock_write_page(struct page *page) +{ + if (!PagePreLocked(page)) + unlock_page(page); +} + +static void logfs_put_write_page(struct page *page) +{ + logfs_unlock_write_page(page); + page_cache_release(page); +} + +static struct page *logfs_get_page(struct inode *inode, u64 bix, level_t level, + int rw) +{ + if (rw == READ) + return logfs_get_read_page(inode, bix, level); + else + return logfs_get_write_page(inode, bix, level); +} + +static void logfs_put_page(struct page *page, int rw) +{ + if (rw == READ) + logfs_put_read_page(page); + else + logfs_put_write_page(page); +} + +static unsigned long __get_bits(u64 val, int skip, int no) +{ + u64 ret = val; + + ret >>= skip * no; + ret <<= 64 - no; + ret >>= 64 - no; + return ret; +} + +static unsigned long get_bits(u64 val, level_t skip) +{ + return __get_bits(val, (__force int)skip, LOGFS_BLOCK_BITS); +} + +static inline void init_shadow_tree(struct super_block *sb, + struct shadow_tree *tree) +{ + struct logfs_super *super = logfs_super(sb); + + btree_init_mempool64(&tree->new, super->s_btree_pool); + btree_init_mempool64(&tree->old, super->s_btree_pool); +} + +static void indirect_write_block(struct logfs_block *block) +{ + struct page *page; + struct inode *inode; + int ret; + + page = block->page; + inode = page->mapping->host; + logfs_lock_write_page(page); + ret = logfs_write_buf(inode, page, 0); + logfs_unlock_write_page(page); + /* + * This needs some rework. Unless you want your filesystem to run + * completely synchronously (you don't), the filesystem will always + * report writes as 'successful' before the actual work has been + * done. The actual work gets done here and this is where any errors + * will show up. And there isn't much we can do about it, really. + * + * Some attempts to fix the errors (move from bad blocks, retry io,...) + * have already been done, so anything left should be either a broken + * device or a bug somewhere in logfs itself. Being relatively new, + * the odds currently favor a bug, so for now the line below isn't + * entirely tasteles. + */ + BUG_ON(ret); +} + +static void inode_write_block(struct logfs_block *block) +{ + struct inode *inode; + int ret; + + inode = block->inode; + if (inode->i_ino == LOGFS_INO_MASTER) + logfs_write_anchor(inode); + else { + ret = __logfs_write_inode(inode, 0); + /* see indirect_write_block comment */ + BUG_ON(ret); + } +} + +static gc_level_t inode_block_level(struct logfs_block *block) +{ + BUG_ON(block->inode->i_ino == LOGFS_INO_MASTER); + return GC_LEVEL(LOGFS_MAX_LEVELS); +} + +static gc_level_t indirect_block_level(struct logfs_block *block) +{ + struct page *page; + struct inode *inode; + u64 bix; + level_t level; + + page = block->page; + inode = page->mapping->host; + logfs_unpack_index(page->index, &bix, &level); + return expand_level(inode->i_ino, level); +} + +/* + * This silences a false, yet annoying gcc warning. I hate it when my editor + * jumps into bitops.h each time I recompile this file. + * TODO: Complain to gcc folks about this and upgrade compiler. + */ +static unsigned long fnb(const unsigned long *addr, + unsigned long size, unsigned long offset) +{ + return find_next_bit(addr, size, offset); +} + +static __be64 inode_val0(struct inode *inode) +{ + struct logfs_inode *li = logfs_inode(inode); + u64 val; + + /* + * Explicit shifting generates good code, but must match the format + * of the structure. Add some paranoia just in case. + */ + BUILD_BUG_ON(offsetof(struct logfs_disk_inode, di_mode) != 0); + BUILD_BUG_ON(offsetof(struct logfs_disk_inode, di_height) != 2); + BUILD_BUG_ON(offsetof(struct logfs_disk_inode, di_flags) != 4); + + val = (u64)inode->i_mode << 48 | + (u64)li->li_height << 40 | + (u64)li->li_flags; + return cpu_to_be64(val); +} + +static int inode_write_alias(struct super_block *sb, + struct logfs_block *block, write_alias_t *write_one_alias) +{ + struct inode *inode = block->inode; + struct logfs_inode *li = logfs_inode(inode); + unsigned long pos; + u64 ino , bix; + __be64 val; + level_t level; + int err; + + for (pos = 0; ; pos++) { + pos = fnb(block->alias_map, LOGFS_BLOCK_FACTOR, pos); + if (pos >= LOGFS_EMBEDDED_FIELDS + INODE_POINTER_OFS) + return 0; + + switch (pos) { + case INODE_HEIGHT_OFS: + val = inode_val0(inode); + break; + case INODE_USED_OFS: + val = cpu_to_be64(li->li_used_bytes);; + break; + case INODE_SIZE_OFS: + val = cpu_to_be64(i_size_read(inode)); + break; + case INODE_POINTER_OFS ... INODE_POINTER_OFS + LOGFS_EMBEDDED_FIELDS - 1: + val = cpu_to_be64(li->li_data[pos - INODE_POINTER_OFS]); + break; + default: + BUG(); + } + + ino = LOGFS_INO_MASTER; + bix = inode->i_ino; + level = LEVEL(0); + err = write_one_alias(sb, ino, bix, level, pos, val); + if (err) + return err; + } +} + +static int indirect_write_alias(struct super_block *sb, + struct logfs_block *block, write_alias_t *write_one_alias) +{ + unsigned long pos; + struct page *page = block->page; + u64 ino , bix; + __be64 *child, val; + level_t level; + int err; + + for (pos = 0; ; pos++) { + pos = fnb(block->alias_map, LOGFS_BLOCK_FACTOR, pos); + if (pos >= LOGFS_BLOCK_FACTOR) + return 0; + + ino = page->mapping->host->i_ino; + logfs_unpack_index(page->index, &bix, &level); + child = kmap_atomic(page, KM_USER0); + val = child[pos]; + kunmap_atomic(child, KM_USER0); + err = write_one_alias(sb, ino, bix, level, pos, val); + if (err) + return err; + } +} + +int logfs_write_obj_aliases_pagecache(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + struct logfs_block *block; + int err; + + list_for_each_entry(block, &super->s_object_alias, alias_list) { + err = block->ops->write_alias(sb, block, write_alias_journal); + if (err) + return err; + } + return 0; +} + +void __free_block(struct super_block *sb, struct logfs_block *block) +{ + BUG_ON(!list_empty(&block->item_list)); + list_del(&block->alias_list); + mempool_free(block, logfs_super(sb)->s_block_pool); +} + +static void inode_free_block(struct super_block *sb, struct logfs_block *block) +{ + struct inode *inode = block->inode; + + logfs_inode(inode)->li_block = NULL; + __free_block(sb, block); +} + +static void indirect_free_block(struct super_block *sb, + struct logfs_block *block) +{ + ClearPagePrivate(block->page); + block->page->private = 0; + __free_block(sb, block); +} + + +static struct logfs_block_ops inode_block_ops = { + .write_block = inode_write_block, + .block_level = inode_block_level, + .free_block = inode_free_block, + .write_alias = inode_write_alias, +}; + +struct logfs_block_ops indirect_block_ops = { + .write_block = indirect_write_block, + .block_level = indirect_block_level, + .free_block = indirect_free_block, + .write_alias = indirect_write_alias, +}; + +struct logfs_block *__alloc_block(struct super_block *sb, + u64 ino, u64 bix, level_t level) +{ + struct logfs_super *super = logfs_super(sb); + struct logfs_block *block; + + block = mempool_alloc(super->s_block_pool, GFP_NOFS); + memset(block, 0, sizeof(*block)); + INIT_LIST_HEAD(&block->alias_list); + INIT_LIST_HEAD(&block->item_list); + block->sb = sb; + block->ino = ino; + block->bix = bix; + block->level = level; + return block; +} + +static void alloc_inode_block(struct inode *inode) +{ + struct logfs_inode *li = logfs_inode(inode); + struct logfs_block *block; + + if (li->li_block) + return; + + block = __alloc_block(inode->i_sb, LOGFS_INO_MASTER, inode->i_ino, 0); + block->inode = inode; + li->li_block = block; + block->ops = &inode_block_ops; +} + +void initialize_block_counters(struct page *page, struct logfs_block *block, + __be64 *array, int page_is_empty) +{ + u64 ptr; + int i, start; + + block->partial = 0; + block->full = 0; + start = 0; + if (page->index < first_indirect_block()) { + /* Counters are pointless on level 0 */ + return; + } + if (page->index == first_indirect_block()) { + /* Skip unused pointers */ + start = I0_BLOCKS; + block->full = I0_BLOCKS; + } + if (!page_is_empty) { + for (i = start; i < LOGFS_BLOCK_FACTOR; i++) { + ptr = be64_to_cpu(array[i]); + if (ptr) + block->partial++; + if (ptr & LOGFS_FULLY_POPULATED) + block->full++; + } + } +} + +static void alloc_data_block(struct inode *inode, struct page *page) +{ + struct logfs_block *block; + u64 bix; + level_t level; + + if (PagePrivate(page)) + return; + + logfs_unpack_index(page->index, &bix, &level); + block = __alloc_block(inode->i_sb, inode->i_ino, bix, level); + block->page = page; + SetPagePrivate(page); + page->private = (unsigned long)block; + block->ops = &indirect_block_ops; +} + +static void alloc_indirect_block(struct inode *inode, struct page *page, + int page_is_empty) +{ + struct logfs_block *block; + __be64 *array; + + if (PagePrivate(page)) + return; + + alloc_data_block(inode, page); + + block = logfs_block(page); + array = kmap_atomic(page, KM_USER0); + initialize_block_counters(page, block, array, page_is_empty); + kunmap_atomic(array, KM_USER0); +} + +static void block_set_pointer(struct page *page, int index, u64 ptr) +{ + struct logfs_block *block = logfs_block(page); + __be64 *array; + u64 oldptr; + + BUG_ON(!block); + array = kmap_atomic(page, KM_USER0); + oldptr = be64_to_cpu(array[index]); + array[index] = cpu_to_be64(ptr); + kunmap_atomic(array, KM_USER0); + SetPageUptodate(page); + + block->full += !!(ptr & LOGFS_FULLY_POPULATED) + - !!(oldptr & LOGFS_FULLY_POPULATED); + block->partial += !!ptr - !!oldptr; +} + +static u64 block_get_pointer(struct page *page, int index) +{ + __be64 *block; + u64 ptr; + + block = kmap_atomic(page, KM_USER0); + ptr = be64_to_cpu(block[index]); + kunmap_atomic(block, KM_USER0); + return ptr; +} + +static int logfs_read_empty(struct page *page) +{ + zero_user_segment(page, 0, PAGE_CACHE_SIZE); + return 0; +} + +static int logfs_read_direct(struct inode *inode, struct page *page) +{ + struct logfs_inode *li = logfs_inode(inode); + pgoff_t index = page->index; + u64 block; + + block = li->li_data[index]; + if (!block) + return logfs_read_empty(page); + + return logfs_segment_read(inode, page, block, index, 0); +} + +static int logfs_read_loop(struct inode *inode, struct page *page, + int rw_context) +{ + struct logfs_inode *li = logfs_inode(inode); + u64 bix, bofs = li->li_data[INDIRECT_INDEX]; + level_t level, target_level; + int ret; + struct page *ipage; + + logfs_unpack_index(page->index, &bix, &target_level); + if (!bofs) + return logfs_read_empty(page); + + if (bix >= maxbix(li->li_height)) + return logfs_read_empty(page); + + for (level = LEVEL(li->li_height); + (__force u8)level > (__force u8)target_level; + level = SUBLEVEL(level)){ + ipage = logfs_get_page(inode, bix, level, rw_context); + if (!ipage) + return -ENOMEM; + + ret = logfs_segment_read(inode, ipage, bofs, bix, level); + if (ret) { + logfs_put_read_page(ipage); + return ret; + } + + bofs = block_get_pointer(ipage, get_bits(bix, SUBLEVEL(level))); + logfs_put_page(ipage, rw_context); + if (!bofs) + return logfs_read_empty(page); + } + + return logfs_segment_read(inode, page, bofs, bix, 0); +} + +static int logfs_read_block(struct inode *inode, struct page *page, + int rw_context) +{ + pgoff_t index = page->index; + + if (index < I0_BLOCKS) + return logfs_read_direct(inode, page); + return logfs_read_loop(inode, page, rw_context); +} + +static int logfs_exist_loop(struct inode *inode, u64 bix) +{ + struct logfs_inode *li = logfs_inode(inode); + u64 bofs = li->li_data[INDIRECT_INDEX]; + level_t level; + int ret; + struct page *ipage; + + if (!bofs) + return 0; + if (bix >= maxbix(li->li_height)) + return 0; + + for (level = LEVEL(li->li_height); level != 0; level = SUBLEVEL(level)) { + ipage = logfs_get_read_page(inode, bix, level); + if (!ipage) + return -ENOMEM; + + ret = logfs_segment_read(inode, ipage, bofs, bix, level); + if (ret) { + logfs_put_read_page(ipage); + return ret; + } + + bofs = block_get_pointer(ipage, get_bits(bix, SUBLEVEL(level))); + logfs_put_read_page(ipage); + if (!bofs) + return 0; + } + + return 1; +} + +int logfs_exist_block(struct inode *inode, u64 bix) +{ + struct logfs_inode *li = logfs_inode(inode); + + if (bix < I0_BLOCKS) + return !!li->li_data[bix]; + return logfs_exist_loop(inode, bix); +} + +static u64 seek_holedata_direct(struct inode *inode, u64 bix, int data) +{ + struct logfs_inode *li = logfs_inode(inode); + + for (; bix < I0_BLOCKS; bix++) + if (data ^ (li->li_data[bix] == 0)) + return bix; + return I0_BLOCKS; +} + +static u64 seek_holedata_loop(struct inode *inode, u64 bix, int data) +{ + struct logfs_inode *li = logfs_inode(inode); + __be64 *rblock; + u64 increment, bofs = li->li_data[INDIRECT_INDEX]; + level_t level; + int ret, slot; + struct page *page; + + BUG_ON(!bofs); + + for (level = LEVEL(li->li_height); level != 0; level = SUBLEVEL(level)) { + increment = 1 << (LOGFS_BLOCK_BITS * ((__force u8)level-1)); + page = logfs_get_read_page(inode, bix, level); + if (!page) + return bix; + + ret = logfs_segment_read(inode, page, bofs, bix, level); + if (ret) { + logfs_put_read_page(page); + return bix; + } + + slot = get_bits(bix, SUBLEVEL(level)); + rblock = kmap_atomic(page, KM_USER0); + while (slot < LOGFS_BLOCK_FACTOR) { + if (data && (rblock[slot] != 0)) + break; + if (!data && !(be64_to_cpu(rblock[slot]) & LOGFS_FULLY_POPULATED)) + break; + slot++; + bix += increment; + bix &= ~(increment - 1); + } + if (slot >= LOGFS_BLOCK_FACTOR) { + kunmap_atomic(rblock, KM_USER0); + logfs_put_read_page(page); + return bix; + } + bofs = be64_to_cpu(rblock[slot]); + kunmap_atomic(rblock, KM_USER0); + logfs_put_read_page(page); + if (!bofs) { + BUG_ON(data); + return bix; + } + } + return bix; +} + +/** + * logfs_seek_hole - find next hole starting at a given block index + * @inode: inode to search in + * @bix: block index to start searching + * + * Returns next hole. If the file doesn't contain any further holes, the + * block address next to eof is returned instead. + */ +u64 logfs_seek_hole(struct inode *inode, u64 bix) +{ + struct logfs_inode *li = logfs_inode(inode); + + if (bix < I0_BLOCKS) { + bix = seek_holedata_direct(inode, bix, 0); + if (bix < I0_BLOCKS) + return bix; + } + + if (!li->li_data[INDIRECT_INDEX]) + return bix; + else if (li->li_data[INDIRECT_INDEX] & LOGFS_FULLY_POPULATED) + bix = maxbix(li->li_height); + else { + bix = seek_holedata_loop(inode, bix, 0); + if (bix < maxbix(li->li_height)) + return bix; + /* Should not happen anymore. But if some port writes semi- + * corrupt images (as this one used to) we might run into it. + */ + WARN_ON_ONCE(bix == maxbix(li->li_height)); + } + + return bix; +} + +static u64 __logfs_seek_data(struct inode *inode, u64 bix) +{ + struct logfs_inode *li = logfs_inode(inode); + + if (bix < I0_BLOCKS) { + bix = seek_holedata_direct(inode, bix, 1); + if (bix < I0_BLOCKS) + return bix; + } + + if (bix < maxbix(li->li_height)) { + if (!li->li_data[INDIRECT_INDEX]) + bix = maxbix(li->li_height); + else + return seek_holedata_loop(inode, bix, 1); + } + + return bix; +} + +/** + * logfs_seek_data - find next data block after a given block index + * @inode: inode to search in + * @bix: block index to start searching + * + * Returns next data block. If the file doesn't contain any further data + * blocks, the last block in the file is returned instead. + */ +u64 logfs_seek_data(struct inode *inode, u64 bix) +{ + struct super_block *sb = inode->i_sb; + u64 ret, end; + + ret = __logfs_seek_data(inode, bix); + end = i_size_read(inode) >> sb->s_blocksize_bits; + if (ret >= end) + ret = max(bix, end); + return ret; +} + +static int logfs_is_valid_direct(struct logfs_inode *li, u64 bix, u64 ofs) +{ + return pure_ofs(li->li_data[bix]) == ofs; +} + +static int __logfs_is_valid_loop(struct inode *inode, u64 bix, + u64 ofs, u64 bofs) +{ + struct logfs_inode *li = logfs_inode(inode); + level_t level; + int ret; + struct page *page; + + for (level = LEVEL(li->li_height); level != 0; level = SUBLEVEL(level)){ + page = logfs_get_write_page(inode, bix, level); + BUG_ON(!page); + + ret = logfs_segment_read(inode, page, bofs, bix, level); + if (ret) { + logfs_put_write_page(page); + return 0; + } + + bofs = block_get_pointer(page, get_bits(bix, SUBLEVEL(level))); + logfs_put_write_page(page); + if (!bofs) + return 0; + + if (pure_ofs(bofs) == ofs) + return 1; + } + return 0; +} + +static int logfs_is_valid_loop(struct inode *inode, u64 bix, u64 ofs) +{ + struct logfs_inode *li = logfs_inode(inode); + u64 bofs = li->li_data[INDIRECT_INDEX]; + + if (!bofs) + return 0; + + if (bix >= maxbix(li->li_height)) + return 0; + + if (pure_ofs(bofs) == ofs) + return 1; + + return __logfs_is_valid_loop(inode, bix, ofs, bofs); +} + +static int __logfs_is_valid_block(struct inode *inode, u64 bix, u64 ofs) +{ + struct logfs_inode *li = logfs_inode(inode); + + if ((inode->i_nlink == 0) && atomic_read(&inode->i_count) == 1) + return 0; + + if (bix < I0_BLOCKS) + return logfs_is_valid_direct(li, bix, ofs); + return logfs_is_valid_loop(inode, bix, ofs); +} + +/** + * logfs_is_valid_block - check whether this block is still valid + * + * @sb - superblock + * @ofs - block physical offset + * @ino - block inode number + * @bix - block index + * @level - block level + * + * Returns 0 if the block is invalid, 1 if it is valid and 2 if it will + * become invalid once the journal is written. + */ +int logfs_is_valid_block(struct super_block *sb, u64 ofs, u64 ino, u64 bix, + gc_level_t gc_level) +{ + struct logfs_super *super = logfs_super(sb); + struct inode *inode; + int ret, cookie; + + /* Umount closes a segment with free blocks remaining. Those + * blocks are by definition invalid. */ + if (ino == -1) + return 0; + + LOGFS_BUG_ON((u64)(u_long)ino != ino, sb); + + inode = logfs_safe_iget(sb, ino, &cookie); + if (IS_ERR(inode)) + goto invalid; + + ret = __logfs_is_valid_block(inode, bix, ofs); + logfs_safe_iput(inode, cookie); + if (ret) + return ret; + +invalid: + /* Block is nominally invalid, but may still sit in the shadow tree, + * waiting for a journal commit. + */ + if (btree_lookup64(&super->s_shadow_tree.old, ofs)) + return 2; + return 0; +} + +int logfs_readpage_nolock(struct page *page) +{ + struct inode *inode = page->mapping->host; + int ret = -EIO; + + ret = logfs_read_block(inode, page, READ); + + if (ret) { + ClearPageUptodate(page); + SetPageError(page); + } else { + SetPageUptodate(page); + ClearPageError(page); + } + flush_dcache_page(page); + + return ret; +} + +static int logfs_reserve_bytes(struct inode *inode, int bytes) +{ + struct logfs_super *super = logfs_super(inode->i_sb); + u64 available = super->s_free_bytes + super->s_dirty_free_bytes + - super->s_dirty_used_bytes - super->s_dirty_pages; + + if (!bytes) + return 0; + + if (available < bytes) + return -ENOSPC; + + if (available < bytes + super->s_root_reserve && + !capable(CAP_SYS_RESOURCE)) + return -ENOSPC; + + return 0; +} + +int get_page_reserve(struct inode *inode, struct page *page) +{ + struct logfs_super *super = logfs_super(inode->i_sb); + int ret; + + if (logfs_block(page) && logfs_block(page)->reserved_bytes) + return 0; + + logfs_get_wblocks(inode->i_sb, page, WF_LOCK); + ret = logfs_reserve_bytes(inode, 6 * LOGFS_MAX_OBJECTSIZE); + if (!ret) { + alloc_data_block(inode, page); + logfs_block(page)->reserved_bytes += 6 * LOGFS_MAX_OBJECTSIZE; + super->s_dirty_pages += 6 * LOGFS_MAX_OBJECTSIZE; + } + logfs_put_wblocks(inode->i_sb, page, WF_LOCK); + return ret; +} + +/* + * We are protected by write lock. Push victims up to superblock level + * and release transaction when appropriate. + */ +/* FIXME: This is currently called from the wrong spots. */ +static void logfs_handle_transaction(struct inode *inode, + struct logfs_transaction *ta) +{ + struct logfs_super *super = logfs_super(inode->i_sb); + + if (!ta) + return; + logfs_inode(inode)->li_block->ta = NULL; + + if (inode->i_ino != LOGFS_INO_MASTER) { + BUG(); /* FIXME: Yes, this needs more thought */ + /* just remember the transaction until inode is written */ + //BUG_ON(logfs_inode(inode)->li_transaction); + //logfs_inode(inode)->li_transaction = ta; + return; + } + + switch (ta->state) { + case CREATE_1: /* fall through */ + case UNLINK_1: + BUG_ON(super->s_victim_ino); + super->s_victim_ino = ta->ino; + break; + case CREATE_2: /* fall through */ + case UNLINK_2: + BUG_ON(super->s_victim_ino != ta->ino); + super->s_victim_ino = 0; + /* transaction ends here - free it */ + kfree(ta); + break; + case CROSS_RENAME_1: + BUG_ON(super->s_rename_dir); + BUG_ON(super->s_rename_pos); + super->s_rename_dir = ta->dir; + super->s_rename_pos = ta->pos; + break; + case CROSS_RENAME_2: + BUG_ON(super->s_rename_dir != ta->dir); + BUG_ON(super->s_rename_pos != ta->pos); + super->s_rename_dir = 0; + super->s_rename_pos = 0; + kfree(ta); + break; + case TARGET_RENAME_1: + BUG_ON(super->s_rename_dir); + BUG_ON(super->s_rename_pos); + BUG_ON(super->s_victim_ino); + super->s_rename_dir = ta->dir; + super->s_rename_pos = ta->pos; + super->s_victim_ino = ta->ino; + break; + case TARGET_RENAME_2: + BUG_ON(super->s_rename_dir != ta->dir); + BUG_ON(super->s_rename_pos != ta->pos); + BUG_ON(super->s_victim_ino != ta->ino); + super->s_rename_dir = 0; + super->s_rename_pos = 0; + break; + case TARGET_RENAME_3: + BUG_ON(super->s_rename_dir); + BUG_ON(super->s_rename_pos); + BUG_ON(super->s_victim_ino != ta->ino); + super->s_victim_ino = 0; + kfree(ta); + break; + default: + BUG(); + } +} + +/* + * Not strictly a reservation, but rather a check that we still have enough + * space to satisfy the write. + */ +static int logfs_reserve_blocks(struct inode *inode, int blocks) +{ + return logfs_reserve_bytes(inode, blocks * LOGFS_MAX_OBJECTSIZE); +} + +struct write_control { + u64 ofs; + long flags; +}; + +static struct logfs_shadow *alloc_shadow(struct inode *inode, u64 bix, + level_t level, u64 old_ofs) +{ + struct logfs_super *super = logfs_super(inode->i_sb); + struct logfs_shadow *shadow; + + shadow = mempool_alloc(super->s_shadow_pool, GFP_NOFS); + memset(shadow, 0, sizeof(*shadow)); + shadow->ino = inode->i_ino; + shadow->bix = bix; + shadow->gc_level = expand_level(inode->i_ino, level); + shadow->old_ofs = old_ofs & ~LOGFS_FULLY_POPULATED; + return shadow; +} + +static void free_shadow(struct inode *inode, struct logfs_shadow *shadow) +{ + struct logfs_super *super = logfs_super(inode->i_sb); + + mempool_free(shadow, super->s_shadow_pool); +} + +/** + * fill_shadow_tree - Propagate shadow tree changes due to a write + * @inode: Inode owning the page + * @page: Struct page that was written + * @shadow: Shadow for the current write + * + * Writes in logfs can result in two semi-valid objects. The old object + * is still valid as long as it can be reached by following pointers on + * the medium. Only when writes propagate all the way up to the journal + * has the new object safely replaced the old one. + * + * To handle this problem, a struct logfs_shadow is used to represent + * every single write. It is attached to the indirect block, which is + * marked dirty. When the indirect block is written, its shadows are + * handed up to the next indirect block (or inode). Untimately they + * will reach the master inode and be freed upon journal commit. + * + * This function handles a single step in the propagation. It adds the + * shadow for the current write to the tree, along with any shadows in + * the page's tree, in case it was an indirect block. If a page is + * written, the inode parameter is left NULL, if an inode is written, + * the page parameter is left NULL. + */ +static void fill_shadow_tree(struct inode *inode, struct page *page, + struct logfs_shadow *shadow) +{ + struct logfs_super *super = logfs_super(inode->i_sb); + struct logfs_block *block = logfs_block(page); + struct shadow_tree *tree = &super->s_shadow_tree; + + if (PagePrivate(page)) { + if (block->alias_map) + super->s_no_object_aliases -= bitmap_weight( + block->alias_map, LOGFS_BLOCK_FACTOR); + logfs_handle_transaction(inode, block->ta); + block->ops->free_block(inode->i_sb, block); + } + if (shadow) { + if (shadow->old_ofs) + btree_insert64(&tree->old, shadow->old_ofs, shadow, + GFP_NOFS); + else + btree_insert64(&tree->new, shadow->new_ofs, shadow, + GFP_NOFS); + + super->s_dirty_used_bytes += shadow->new_len; + super->s_dirty_free_bytes += shadow->old_len; + } +} + +static void logfs_set_alias(struct super_block *sb, struct logfs_block *block, + long child_no) +{ + struct logfs_super *super = logfs_super(sb); + + if (block->inode && block->inode->i_ino == LOGFS_INO_MASTER) { + /* Aliases in the master inode are pointless. */ + return; + } + + if (!test_bit(child_no, block->alias_map)) { + set_bit(child_no, block->alias_map); + super->s_no_object_aliases++; + } + list_move_tail(&block->alias_list, &super->s_object_alias); +} + +/* + * Object aliases can and often do change the size and occupied space of a + * file. So not only do we have to change the pointers, we also have to + * change inode->i_size and li->li_used_bytes. Which is done by setting + * another two object aliases for the inode itself. + */ +static void set_iused(struct inode *inode, struct logfs_shadow *shadow) +{ + struct logfs_inode *li = logfs_inode(inode); + + if (shadow->new_len == shadow->old_len) + return; + + alloc_inode_block(inode); + li->li_used_bytes += shadow->new_len - shadow->old_len; + __logfs_set_blocks(inode); + logfs_set_alias(inode->i_sb, li->li_block, INODE_USED_OFS); + logfs_set_alias(inode->i_sb, li->li_block, INODE_SIZE_OFS); +} + +static int logfs_write_i0(struct inode *inode, struct page *page, + struct write_control *wc) +{ + struct logfs_shadow *shadow; + u64 bix; + level_t level; + int full, err = 0; + + logfs_unpack_index(page->index, &bix, &level); + if (wc->ofs == 0) + if (logfs_reserve_blocks(inode, 1)) + return -ENOSPC; + + shadow = alloc_shadow(inode, bix, level, wc->ofs); + if (wc->flags & WF_WRITE) + err = logfs_segment_write(inode, page, shadow); + if (wc->flags & WF_DELETE) + logfs_segment_delete(inode, shadow); + if (err) { + free_shadow(inode, shadow); + return err; + } + + set_iused(inode, shadow); + full = 1; + if (level != 0) { + alloc_indirect_block(inode, page, 0); + full = logfs_block(page)->full == LOGFS_BLOCK_FACTOR; + } + fill_shadow_tree(inode, page, shadow); + wc->ofs = shadow->new_ofs; + if (wc->ofs && full) + wc->ofs |= LOGFS_FULLY_POPULATED; + return 0; +} + +static int logfs_write_direct(struct inode *inode, struct page *page, + long flags) +{ + struct logfs_inode *li = logfs_inode(inode); + struct write_control wc = { + .ofs = li->li_data[page->index], + .flags = flags, + }; + int err; + + alloc_inode_block(inode); + + err = logfs_write_i0(inode, page, &wc); + if (err) + return err; + + li->li_data[page->index] = wc.ofs; + logfs_set_alias(inode->i_sb, li->li_block, + page->index + INODE_POINTER_OFS); + return 0; +} + +static int ptr_change(u64 ofs, struct page *page) +{ + struct logfs_block *block = logfs_block(page); + int empty0, empty1, full0, full1; + + empty0 = ofs == 0; + empty1 = block->partial == 0; + if (empty0 != empty1) + return 1; + + /* The !! is necessary to shrink result to int */ + full0 = !!(ofs & LOGFS_FULLY_POPULATED); + full1 = block->full == LOGFS_BLOCK_FACTOR; + if (full0 != full1) + return 1; + return 0; +} + +static int __logfs_write_rec(struct inode *inode, struct page *page, + struct write_control *this_wc, + pgoff_t bix, level_t target_level, level_t level) +{ + int ret, page_empty = 0; + int child_no = get_bits(bix, SUBLEVEL(level)); + struct page *ipage; + struct write_control child_wc = { + .flags = this_wc->flags, + }; + + ipage = logfs_get_write_page(inode, bix, level); + if (!ipage) + return -ENOMEM; + + if (this_wc->ofs) { + ret = logfs_segment_read(inode, ipage, this_wc->ofs, bix, level); + if (ret) + goto out; + } else if (!PageUptodate(ipage)) { + page_empty = 1; + logfs_read_empty(ipage); + } + + child_wc.ofs = block_get_pointer(ipage, child_no); + + if ((__force u8)level-1 > (__force u8)target_level) + ret = __logfs_write_rec(inode, page, &child_wc, bix, + target_level, SUBLEVEL(level)); + else + ret = logfs_write_i0(inode, page, &child_wc); + + if (ret) + goto out; + + alloc_indirect_block(inode, ipage, page_empty); + block_set_pointer(ipage, child_no, child_wc.ofs); + /* FIXME: first condition seems superfluous */ + if (child_wc.ofs || logfs_block(ipage)->partial) + this_wc->flags |= WF_WRITE; + /* the condition on this_wc->ofs ensures that we won't consume extra + * space for indirect blocks in the future, which we cannot reserve */ + if (!this_wc->ofs || ptr_change(this_wc->ofs, ipage)) + ret = logfs_write_i0(inode, ipage, this_wc); + else + logfs_set_alias(inode->i_sb, logfs_block(ipage), child_no); +out: + logfs_put_write_page(ipage); + return ret; +} + +static int logfs_write_rec(struct inode *inode, struct page *page, + pgoff_t bix, level_t target_level, long flags) +{ + struct logfs_inode *li = logfs_inode(inode); + struct write_control wc = { + .ofs = li->li_data[INDIRECT_INDEX], + .flags = flags, + }; + int ret; + + alloc_inode_block(inode); + + if (li->li_height > (__force u8)target_level) + ret = __logfs_write_rec(inode, page, &wc, bix, target_level, + LEVEL(li->li_height)); + else + ret = logfs_write_i0(inode, page, &wc); + if (ret) + return ret; + + if (li->li_data[INDIRECT_INDEX] != wc.ofs) { + li->li_data[INDIRECT_INDEX] = wc.ofs; + logfs_set_alias(inode->i_sb, li->li_block, + INDIRECT_INDEX + INODE_POINTER_OFS); + } + return ret; +} + +void logfs_add_transaction(struct inode *inode, struct logfs_transaction *ta) +{ + alloc_inode_block(inode); + logfs_inode(inode)->li_block->ta = ta; +} + +void logfs_del_transaction(struct inode *inode, struct logfs_transaction *ta) +{ + struct logfs_block *block = logfs_inode(inode)->li_block; + + if (block && block->ta) + block->ta = NULL; +} + +static int grow_inode(struct inode *inode, u64 bix, level_t level) +{ + struct logfs_inode *li = logfs_inode(inode); + u8 height = (__force u8)level; + struct page *page; + struct write_control wc = { + .flags = WF_WRITE, + }; + int err; + + BUG_ON(height > 5 || li->li_height > 5); + while (height > li->li_height || bix >= maxbix(li->li_height)) { + page = logfs_get_write_page(inode, I0_BLOCKS + 1, + LEVEL(li->li_height + 1)); + if (!page) + return -ENOMEM; + logfs_read_empty(page); + alloc_indirect_block(inode, page, 1); + block_set_pointer(page, 0, li->li_data[INDIRECT_INDEX]); + err = logfs_write_i0(inode, page, &wc); + logfs_put_write_page(page); + if (err) + return err; + li->li_data[INDIRECT_INDEX] = wc.ofs; + wc.ofs = 0; + li->li_height++; + logfs_set_alias(inode->i_sb, li->li_block, INODE_HEIGHT_OFS); + } + return 0; +} + +static int __logfs_write_buf(struct inode *inode, struct page *page, long flags) +{ + struct logfs_super *super = logfs_super(inode->i_sb); + pgoff_t index = page->index; + u64 bix; + level_t level; + int err; + + flags |= WF_WRITE | WF_DELETE; + inode->i_ctime = inode->i_mtime = CURRENT_TIME; + + logfs_unpack_index(index, &bix, &level); + if (logfs_block(page) && logfs_block(page)->reserved_bytes) + super->s_dirty_pages -= logfs_block(page)->reserved_bytes; + + if (index < I0_BLOCKS) + return logfs_write_direct(inode, page, flags); + + bix = adjust_bix(bix, level); + err = grow_inode(inode, bix, level); + if (err) + return err; + return logfs_write_rec(inode, page, bix, level, flags); +} + +int logfs_write_buf(struct inode *inode, struct page *page, long flags) +{ + struct super_block *sb = inode->i_sb; + int ret; + + logfs_get_wblocks(sb, page, flags & WF_LOCK); + ret = __logfs_write_buf(inode, page, flags); + logfs_put_wblocks(sb, page, flags & WF_LOCK); + return ret; +} + +static int __logfs_delete(struct inode *inode, struct page *page) +{ + long flags = WF_DELETE; + + inode->i_ctime = inode->i_mtime = CURRENT_TIME; + + if (page->index < I0_BLOCKS) + return logfs_write_direct(inode, page, flags); + return logfs_write_rec(inode, page, page->index, 0, flags); +} + +int logfs_delete(struct inode *inode, pgoff_t index, + struct shadow_tree *shadow_tree) +{ + struct super_block *sb = inode->i_sb; + struct page *page; + int ret; + + page = logfs_get_read_page(inode, index, 0); + if (!page) + return -ENOMEM; + + logfs_get_wblocks(sb, page, 1); + ret = __logfs_delete(inode, page); + logfs_put_wblocks(sb, page, 1); + + logfs_put_read_page(page); + + return ret; +} + +/* Rewrite cannot mark the inode dirty but has to write it immediatly. */ +int logfs_rewrite_block(struct inode *inode, u64 bix, u64 ofs, + gc_level_t gc_level, long flags) +{ + level_t level = shrink_level(gc_level); + struct page *page; + int err; + + page = logfs_get_write_page(inode, bix, level); + if (!page) + return -ENOMEM; + + err = logfs_segment_read(inode, page, ofs, bix, level); + if (!err) { + if (level != 0) + alloc_indirect_block(inode, page, 0); + err = logfs_write_buf(inode, page, flags); + } + logfs_put_write_page(page); + return err; +} + +static int truncate_data_block(struct inode *inode, struct page *page, + u64 ofs, struct logfs_shadow *shadow, u64 size) +{ + loff_t pageofs = page->index << inode->i_sb->s_blocksize_bits; + u64 bix; + level_t level; + int err; + + /* Does truncation happen within this page? */ + if (size <= pageofs || size - pageofs >= PAGE_SIZE) + return 0; + + logfs_unpack_index(page->index, &bix, &level); + BUG_ON(level != 0); + + err = logfs_segment_read(inode, page, ofs, bix, level); + if (err) + return err; + + zero_user_segment(page, size - pageofs, PAGE_CACHE_SIZE); + return logfs_segment_write(inode, page, shadow); +} + +static int logfs_truncate_i0(struct inode *inode, struct page *page, + struct write_control *wc, u64 size) +{ + struct logfs_shadow *shadow; + u64 bix; + level_t level; + int err = 0; + + logfs_unpack_index(page->index, &bix, &level); + BUG_ON(level != 0); + shadow = alloc_shadow(inode, bix, level, wc->ofs); + + err = truncate_data_block(inode, page, wc->ofs, shadow, size); + if (err) { + free_shadow(inode, shadow); + return err; + } + + logfs_segment_delete(inode, shadow); + set_iused(inode, shadow); + fill_shadow_tree(inode, page, shadow); + wc->ofs = shadow->new_ofs; + return 0; +} + +static int logfs_truncate_direct(struct inode *inode, u64 size) +{ + struct logfs_inode *li = logfs_inode(inode); + struct write_control wc; + struct page *page; + int e; + int err; + + alloc_inode_block(inode); + + for (e = I0_BLOCKS - 1; e >= 0; e--) { + if (size > (e+1) * LOGFS_BLOCKSIZE) + break; + + wc.ofs = li->li_data[e]; + if (!wc.ofs) + continue; + + page = logfs_get_write_page(inode, e, 0); + if (!page) + return -ENOMEM; + err = logfs_segment_read(inode, page, wc.ofs, e, 0); + if (err) { + logfs_put_write_page(page); + return err; + } + err = logfs_truncate_i0(inode, page, &wc, size); + logfs_put_write_page(page); + if (err) + return err; + + li->li_data[e] = wc.ofs; + } + return 0; +} + +/* FIXME: these need to become per-sb once we support different blocksizes */ +static u64 __logfs_step[] = { + 1, + I1_BLOCKS, + I2_BLOCKS, + I3_BLOCKS, +}; + +static u64 __logfs_start_index[] = { + I0_BLOCKS, + I1_BLOCKS, + I2_BLOCKS, + I3_BLOCKS +}; + +static inline u64 logfs_step(level_t level) +{ + return __logfs_step[(__force u8)level]; +} + +static inline u64 logfs_factor(u8 level) +{ + return __logfs_step[level] * LOGFS_BLOCKSIZE; +} + +static inline u64 logfs_start_index(level_t level) +{ + return __logfs_start_index[(__force u8)level]; +} + +static void logfs_unpack_raw_index(pgoff_t index, u64 *bix, level_t *level) +{ + logfs_unpack_index(index, bix, level); + if (*bix <= logfs_start_index(SUBLEVEL(*level))) + *bix = 0; +} + +static int __logfs_truncate_rec(struct inode *inode, struct page *ipage, + struct write_control *this_wc, u64 size) +{ + int truncate_happened = 0; + int e, err = 0; + u64 bix, child_bix, next_bix; + level_t level; + struct page *page; + struct write_control child_wc = { /* FIXME: flags */ }; + + logfs_unpack_raw_index(ipage->index, &bix, &level); + err = logfs_segment_read(inode, ipage, this_wc->ofs, bix, level); + if (err) + return err; + + for (e = LOGFS_BLOCK_FACTOR - 1; e >= 0; e--) { + child_bix = bix + e * logfs_step(SUBLEVEL(level)); + next_bix = child_bix + logfs_step(SUBLEVEL(level)); + if (size > next_bix * LOGFS_BLOCKSIZE) + break; + + child_wc.ofs = pure_ofs(block_get_pointer(ipage, e)); + if (!child_wc.ofs) + continue; + + page = logfs_get_write_page(inode, child_bix, SUBLEVEL(level)); + if (!page) + return -ENOMEM; + + if ((__force u8)level > 1) + err = __logfs_truncate_rec(inode, page, &child_wc, size); + else + err = logfs_truncate_i0(inode, page, &child_wc, size); + logfs_put_write_page(page); + if (err) + return err; + + truncate_happened = 1; + alloc_indirect_block(inode, ipage, 0); + block_set_pointer(ipage, e, child_wc.ofs); + } + + if (!truncate_happened) { + printk("ineffectual truncate (%lx, %lx, %llx)\n", inode->i_ino, ipage->index, size); + return 0; + } + + this_wc->flags = WF_DELETE; + if (logfs_block(ipage)->partial) + this_wc->flags |= WF_WRITE; + + return logfs_write_i0(inode, ipage, this_wc); +} + +static int logfs_truncate_rec(struct inode *inode, u64 size) +{ + struct logfs_inode *li = logfs_inode(inode); + struct write_control wc = { + .ofs = li->li_data[INDIRECT_INDEX], + }; + struct page *page; + int err; + + alloc_inode_block(inode); + + if (!wc.ofs) + return 0; + + page = logfs_get_write_page(inode, 0, LEVEL(li->li_height)); + if (!page) + return -ENOMEM; + + err = __logfs_truncate_rec(inode, page, &wc, size); + logfs_put_write_page(page); + if (err) + return err; + + if (li->li_data[INDIRECT_INDEX] != wc.ofs) + li->li_data[INDIRECT_INDEX] = wc.ofs; + return 0; +} + +static int __logfs_truncate(struct inode *inode, u64 size) +{ + int ret; + + if (size >= logfs_factor(logfs_inode(inode)->li_height)) + return 0; + + ret = logfs_truncate_rec(inode, size); + if (ret) + return ret; + + return logfs_truncate_direct(inode, size); +} + +int logfs_truncate(struct inode *inode, u64 size) +{ + struct super_block *sb = inode->i_sb; + int err; + + logfs_get_wblocks(sb, NULL, 1); + err = __logfs_truncate(inode, size); + if (!err) + err = __logfs_write_inode(inode, 0); + logfs_put_wblocks(sb, NULL, 1); + + if (!err) + err = vmtruncate(inode, size); + + /* I don't trust error recovery yet. */ + WARN_ON(err); + return err; +} + +static void move_page_to_inode(struct inode *inode, struct page *page) +{ + struct logfs_inode *li = logfs_inode(inode); + struct logfs_block *block = logfs_block(page); + + if (!block) + return; + + log_blockmove("move_page_to_inode(%llx, %llx, %x)\n", + block->ino, block->bix, block->level); + BUG_ON(li->li_block); + block->ops = &inode_block_ops; + block->inode = inode; + li->li_block = block; + + block->page = NULL; + page->private = 0; + ClearPagePrivate(page); +} + +static void move_inode_to_page(struct page *page, struct inode *inode) +{ + struct logfs_inode *li = logfs_inode(inode); + struct logfs_block *block = li->li_block; + + if (!block) + return; + + log_blockmove("move_inode_to_page(%llx, %llx, %x)\n", + block->ino, block->bix, block->level); + BUG_ON(PagePrivate(page)); + block->ops = &indirect_block_ops; + block->page = page; + page->private = (unsigned long)block; + SetPagePrivate(page); + + block->inode = NULL; + li->li_block = NULL; +} + +int logfs_read_inode(struct inode *inode) +{ + struct super_block *sb = inode->i_sb; + struct logfs_super *super = logfs_super(sb); + struct inode *master_inode = super->s_master_inode; + struct page *page; + struct logfs_disk_inode *di; + u64 ino = inode->i_ino; + + if (ino << sb->s_blocksize_bits > i_size_read(master_inode)) + return -ENODATA; + if (!logfs_exist_block(master_inode, ino)) + return -ENODATA; + + page = read_cache_page(master_inode->i_mapping, ino, + (filler_t *)logfs_readpage, NULL); + if (IS_ERR(page)) + return PTR_ERR(page); + + di = kmap_atomic(page, KM_USER0); + logfs_disk_to_inode(di, inode); + kunmap_atomic(di, KM_USER0); + move_page_to_inode(inode, page); + page_cache_release(page); + return 0; +} + +/* Caller must logfs_put_write_page(page); */ +static struct page *inode_to_page(struct inode *inode) +{ + struct inode *master_inode = logfs_super(inode->i_sb)->s_master_inode; + struct logfs_disk_inode *di; + struct page *page; + + BUG_ON(inode->i_ino == LOGFS_INO_MASTER); + + page = logfs_get_write_page(master_inode, inode->i_ino, 0); + if (!page) + return NULL; + + di = kmap_atomic(page, KM_USER0); + logfs_inode_to_disk(inode, di); + kunmap_atomic(di, KM_USER0); + move_inode_to_page(page, inode); + return page; +} + +/* Cheaper version of write_inode. All changes are concealed in + * aliases, which are moved back. No write to the medium happens. + */ +void logfs_clear_inode(struct inode *inode) +{ + struct super_block *sb = inode->i_sb; + struct logfs_inode *li = logfs_inode(inode); + struct logfs_block *block = li->li_block; + struct page *page; + + /* Only deleted files may be dirty at this point */ + BUG_ON(inode->i_state & I_DIRTY && inode->i_nlink); + if (!block) + return; + if ((logfs_super(sb)->s_flags & LOGFS_SB_FLAG_SHUTDOWN)) { + block->ops->free_block(inode->i_sb, block); + return; + } + + BUG_ON(inode->i_ino < LOGFS_RESERVED_INOS); + page = inode_to_page(inode); + BUG_ON(!page); /* FIXME: Use emergency page */ + logfs_put_write_page(page); +} + +static int do_write_inode(struct inode *inode) +{ + struct super_block *sb = inode->i_sb; + struct inode *master_inode = logfs_super(sb)->s_master_inode; + loff_t size = (inode->i_ino + 1) << inode->i_sb->s_blocksize_bits; + struct page *page; + int err; + + BUG_ON(inode->i_ino == LOGFS_INO_MASTER); + /* FIXME: lock inode */ + + if (i_size_read(master_inode) < size) + i_size_write(master_inode, size); + + /* TODO: Tell vfs this inode is clean now */ + + page = inode_to_page(inode); + if (!page) + return -ENOMEM; + + /* FIXME: transaction is part of logfs_block now. Is that enough? */ + err = logfs_write_buf(master_inode, page, 0); + logfs_put_write_page(page); + return err; +} + +static void logfs_mod_segment_entry(struct super_block *sb, u32 segno, + int write, + void (*change_se)(struct logfs_segment_entry *, long), + long arg) +{ + struct logfs_super *super = logfs_super(sb); + struct inode *inode; + struct page *page; + struct logfs_segment_entry *se; + pgoff_t page_no; + int child_no; + + page_no = segno >> (sb->s_blocksize_bits - 3); + child_no = segno & ((sb->s_blocksize >> 3) - 1); + + inode = super->s_segfile_inode; + page = logfs_get_write_page(inode, page_no, 0); + BUG_ON(!page); /* FIXME: We need some reserve page for this case */ + if (!PageUptodate(page)) + logfs_read_block(inode, page, WRITE); + + if (write) + alloc_indirect_block(inode, page, 0); + se = kmap_atomic(page, KM_USER0); + change_se(se + child_no, arg); + if (write) { + logfs_set_alias(sb, logfs_block(page), child_no); + BUG_ON((int)be32_to_cpu(se[child_no].valid) > super->s_segsize); + } + kunmap_atomic(se, KM_USER0); + + logfs_put_write_page(page); +} + +static void __get_segment_entry(struct logfs_segment_entry *se, long _target) +{ + struct logfs_segment_entry *target = (void *)_target; + + *target = *se; +} + +void logfs_get_segment_entry(struct super_block *sb, u32 segno, + struct logfs_segment_entry *se) +{ + logfs_mod_segment_entry(sb, segno, 0, __get_segment_entry, (long)se); +} + +static void __set_segment_used(struct logfs_segment_entry *se, long increment) +{ + u32 valid; + + valid = be32_to_cpu(se->valid); + valid += increment; + se->valid = cpu_to_be32(valid); +} + +void logfs_set_segment_used(struct super_block *sb, u64 ofs, int increment) +{ + struct logfs_super *super = logfs_super(sb); + u32 segno = ofs >> super->s_segshift; + + if (!increment) + return; + + logfs_mod_segment_entry(sb, segno, 1, __set_segment_used, increment); +} + +static void __set_segment_erased(struct logfs_segment_entry *se, long ec_level) +{ + se->ec_level = cpu_to_be32(ec_level); +} + +void logfs_set_segment_erased(struct super_block *sb, u32 segno, u32 ec, + gc_level_t gc_level) +{ + u32 ec_level = ec << 4 | (__force u8)gc_level; + + logfs_mod_segment_entry(sb, segno, 1, __set_segment_erased, ec_level); +} + +static void __set_segment_reserved(struct logfs_segment_entry *se, long ignore) +{ + se->valid = cpu_to_be32(RESERVED); +} + +void logfs_set_segment_reserved(struct super_block *sb, u32 segno) +{ + logfs_mod_segment_entry(sb, segno, 1, __set_segment_reserved, 0); +} + +static void __set_segment_unreserved(struct logfs_segment_entry *se, + long ec_level) +{ + se->valid = 0; + se->ec_level = cpu_to_be32(ec_level); +} + +void logfs_set_segment_unreserved(struct super_block *sb, u32 segno, u32 ec) +{ + u32 ec_level = ec << 4; + + logfs_mod_segment_entry(sb, segno, 1, __set_segment_unreserved, + ec_level); +} + +int __logfs_write_inode(struct inode *inode, long flags) +{ + struct super_block *sb = inode->i_sb; + int ret; + + logfs_get_wblocks(sb, NULL, flags & WF_LOCK); + ret = do_write_inode(inode); + logfs_put_wblocks(sb, NULL, flags & WF_LOCK); + return ret; +} + +static int do_delete_inode(struct inode *inode) +{ + struct super_block *sb = inode->i_sb; + struct inode *master_inode = logfs_super(sb)->s_master_inode; + struct page *page; + int ret; + + page = logfs_get_write_page(master_inode, inode->i_ino, 0); + if (!page) + return -ENOMEM; + + move_inode_to_page(page, inode); + + logfs_get_wblocks(sb, page, 1); + ret = __logfs_delete(master_inode, page); + logfs_put_wblocks(sb, page, 1); + + logfs_put_write_page(page); + return ret; +} + +/* + * ZOMBIE inodes have already been deleted before and should remain dead, + * if it weren't for valid checking. No need to kill them again here. + */ +void logfs_delete_inode(struct inode *inode) +{ + struct logfs_inode *li = logfs_inode(inode); + + if (!(li->li_flags & LOGFS_IF_ZOMBIE)) { + li->li_flags |= LOGFS_IF_ZOMBIE; + if (i_size_read(inode) > 0) + logfs_truncate(inode, 0); + do_delete_inode(inode); + } + truncate_inode_pages(&inode->i_data, 0); + clear_inode(inode); +} + +void btree_write_block(struct logfs_block *block) +{ + struct inode *inode; + struct page *page; + int err, cookie; + + inode = logfs_safe_iget(block->sb, block->ino, &cookie); + page = logfs_get_write_page(inode, block->bix, block->level); + + err = logfs_readpage_nolock(page); + BUG_ON(err); + BUG_ON(!PagePrivate(page)); + BUG_ON(logfs_block(page) != block); + err = __logfs_write_buf(inode, page, 0); + BUG_ON(err); + BUG_ON(PagePrivate(page) || page->private); + + logfs_put_write_page(page); + logfs_safe_iput(inode, cookie); +} + +/** + * logfs_inode_write - write inode or dentry objects + * + * @inode: parent inode (ifile or directory) + * @buf: object to write (inode or dentry) + * @n: object size + * @_pos: object number (file position in blocks/objects) + * @flags: write flags + * @lock: 0 if write lock is already taken, 1 otherwise + * @shadow_tree: shadow below this inode + * + * FIXME: All caller of this put a 200-300 byte variable on the stack, + * only to call here and do a memcpy from that stack variable. A good + * example of wasted performance and stack space. + */ +int logfs_inode_write(struct inode *inode, const void *buf, size_t count, + loff_t bix, long flags, struct shadow_tree *shadow_tree) +{ + loff_t pos = bix << inode->i_sb->s_blocksize_bits; + int err; + struct page *page; + void *pagebuf; + + BUG_ON(pos & (LOGFS_BLOCKSIZE-1)); + BUG_ON(count > LOGFS_BLOCKSIZE); + page = logfs_get_write_page(inode, bix, 0); + if (!page) + return -ENOMEM; + + pagebuf = kmap_atomic(page, KM_USER0); + memcpy(pagebuf, buf, count); + flush_dcache_page(page); + kunmap_atomic(pagebuf, KM_USER0); + + if (i_size_read(inode) < pos + LOGFS_BLOCKSIZE) + i_size_write(inode, pos + LOGFS_BLOCKSIZE); + + err = logfs_write_buf(inode, page, flags); + logfs_put_write_page(page); + return err; +} + +int logfs_open_segfile(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + struct inode *inode; + + inode = logfs_read_meta_inode(sb, LOGFS_INO_SEGFILE); + if (IS_ERR(inode)) + return PTR_ERR(inode); + super->s_segfile_inode = inode; + return 0; +} + +int logfs_init_rw(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + int min_fill = 3 * super->s_no_blocks; + + INIT_LIST_HEAD(&super->s_object_alias); + mutex_init(&super->s_write_mutex); + super->s_block_pool = mempool_create_kmalloc_pool(min_fill, + sizeof(struct logfs_block)); + super->s_shadow_pool = mempool_create_kmalloc_pool(min_fill, + sizeof(struct logfs_shadow)); + return 0; +} + +void logfs_cleanup_rw(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + + destroy_meta_inode(super->s_segfile_inode); + if (super->s_block_pool) + mempool_destroy(super->s_block_pool); + if (super->s_shadow_pool) + mempool_destroy(super->s_shadow_pool); +} diff --git a/fs/logfs/segment.c b/fs/logfs/segment.c new file mode 100644 index 00000000000..5f58b74516c --- /dev/null +++ b/fs/logfs/segment.c @@ -0,0 +1,924 @@ +/* + * fs/logfs/segment.c - Handling the Object Store + * + * As should be obvious for Linux kernel code, license is GPLv2 + * + * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org> + * + * Object store or ostore makes up the complete device with exception of + * the superblock and journal areas. Apart from its own metadata it stores + * three kinds of objects: inodes, dentries and blocks, both data and indirect. + */ +#include "logfs.h" + +static int logfs_mark_segment_bad(struct super_block *sb, u32 segno) +{ + struct logfs_super *super = logfs_super(sb); + struct btree_head32 *head = &super->s_reserved_segments; + int err; + + err = btree_insert32(head, segno, (void *)1, GFP_NOFS); + if (err) + return err; + logfs_super(sb)->s_bad_segments++; + /* FIXME: write to journal */ + return 0; +} + +int logfs_erase_segment(struct super_block *sb, u32 segno) +{ + struct logfs_super *super = logfs_super(sb); + + super->s_gec++; + + return super->s_devops->erase(sb, (u64)segno << super->s_segshift, + super->s_segsize); +} + +static s64 logfs_get_free_bytes(struct logfs_area *area, size_t bytes) +{ + s32 ofs; + + logfs_open_area(area, bytes); + + ofs = area->a_used_bytes; + area->a_used_bytes += bytes; + BUG_ON(area->a_used_bytes >= logfs_super(area->a_sb)->s_segsize); + + return dev_ofs(area->a_sb, area->a_segno, ofs); +} + +static struct page *get_mapping_page(struct super_block *sb, pgoff_t index, + int use_filler) +{ + struct logfs_super *super = logfs_super(sb); + struct address_space *mapping = super->s_mapping_inode->i_mapping; + filler_t *filler = super->s_devops->readpage; + struct page *page; + + BUG_ON(mapping_gfp_mask(mapping) & __GFP_FS); + if (use_filler) + page = read_cache_page(mapping, index, filler, sb); + else { + page = find_or_create_page(mapping, index, GFP_NOFS); + unlock_page(page); + } + return page; +} + +void __logfs_buf_write(struct logfs_area *area, u64 ofs, void *buf, size_t len, + int use_filler) +{ + pgoff_t index = ofs >> PAGE_SHIFT; + struct page *page; + long offset = ofs & (PAGE_SIZE-1); + long copylen; + + /* Only logfs_wbuf_recover may use len==0 */ + BUG_ON(!len && !use_filler); + do { + copylen = min((ulong)len, PAGE_SIZE - offset); + + page = get_mapping_page(area->a_sb, index, use_filler); + SetPageUptodate(page); + BUG_ON(!page); /* FIXME: reserve a pool */ + memcpy(page_address(page) + offset, buf, copylen); + SetPagePrivate(page); + page_cache_release(page); + + buf += copylen; + len -= copylen; + offset = 0; + index++; + } while (len); +} + +/* + * bdev_writeseg will write full pages. Memset the tail to prevent data leaks. + */ +static void pad_wbuf(struct logfs_area *area, int final) +{ + struct super_block *sb = area->a_sb; + struct logfs_super *super = logfs_super(sb); + struct page *page; + u64 ofs = dev_ofs(sb, area->a_segno, area->a_used_bytes); + pgoff_t index = ofs >> PAGE_SHIFT; + long offset = ofs & (PAGE_SIZE-1); + u32 len = PAGE_SIZE - offset; + + if (len == PAGE_SIZE) { + /* The math in this function can surely use some love */ + len = 0; + } + if (len) { + BUG_ON(area->a_used_bytes >= super->s_segsize); + + page = get_mapping_page(area->a_sb, index, 0); + BUG_ON(!page); /* FIXME: reserve a pool */ + memset(page_address(page) + offset, 0xff, len); + SetPagePrivate(page); + page_cache_release(page); + } + + if (!final) + return; + + area->a_used_bytes += len; + for ( ; area->a_used_bytes < super->s_segsize; + area->a_used_bytes += PAGE_SIZE) { + /* Memset another page */ + index++; + page = get_mapping_page(area->a_sb, index, 0); + BUG_ON(!page); /* FIXME: reserve a pool */ + memset(page_address(page), 0xff, PAGE_SIZE); + SetPagePrivate(page); + page_cache_release(page); + } +} + +/* + * We have to be careful with the alias tree. Since lookup is done by bix, + * it needs to be normalized, so 14, 15, 16, etc. all match when dealing with + * indirect blocks. So always use it through accessor functions. + */ +static void *alias_tree_lookup(struct super_block *sb, u64 ino, u64 bix, + level_t level) +{ + struct btree_head128 *head = &logfs_super(sb)->s_object_alias_tree; + pgoff_t index = logfs_pack_index(bix, level); + + return btree_lookup128(head, ino, index); +} + +static int alias_tree_insert(struct super_block *sb, u64 ino, u64 bix, + level_t level, void *val) +{ + struct btree_head128 *head = &logfs_super(sb)->s_object_alias_tree; + pgoff_t index = logfs_pack_index(bix, level); + + return btree_insert128(head, ino, index, val, GFP_NOFS); +} + +static int btree_write_alias(struct super_block *sb, struct logfs_block *block, + write_alias_t *write_one_alias) +{ + struct object_alias_item *item; + int err; + + list_for_each_entry(item, &block->item_list, list) { + err = write_alias_journal(sb, block->ino, block->bix, + block->level, item->child_no, item->val); + if (err) + return err; + } + return 0; +} + +static gc_level_t btree_block_level(struct logfs_block *block) +{ + return expand_level(block->ino, block->level); +} + +static struct logfs_block_ops btree_block_ops = { + .write_block = btree_write_block, + .block_level = btree_block_level, + .free_block = __free_block, + .write_alias = btree_write_alias, +}; + +int logfs_load_object_aliases(struct super_block *sb, + struct logfs_obj_alias *oa, int count) +{ + struct logfs_super *super = logfs_super(sb); + struct logfs_block *block; + struct object_alias_item *item; + u64 ino, bix; + level_t level; + int i, err; + + super->s_flags |= LOGFS_SB_FLAG_OBJ_ALIAS; + count /= sizeof(*oa); + for (i = 0; i < count; i++) { + item = mempool_alloc(super->s_alias_pool, GFP_NOFS); + if (!item) + return -ENOMEM; + memset(item, 0, sizeof(*item)); + + super->s_no_object_aliases++; + item->val = oa[i].val; + item->child_no = be16_to_cpu(oa[i].child_no); + + ino = be64_to_cpu(oa[i].ino); + bix = be64_to_cpu(oa[i].bix); + level = LEVEL(oa[i].level); + + log_aliases("logfs_load_object_aliases(%llx, %llx, %x, %x) %llx\n", + ino, bix, level, item->child_no, + be64_to_cpu(item->val)); + block = alias_tree_lookup(sb, ino, bix, level); + if (!block) { + block = __alloc_block(sb, ino, bix, level); + block->ops = &btree_block_ops; + err = alias_tree_insert(sb, ino, bix, level, block); + BUG_ON(err); /* mempool empty */ + } + if (test_and_set_bit(item->child_no, block->alias_map)) { + printk(KERN_ERR"LogFS: Alias collision detected\n"); + return -EIO; + } + list_move_tail(&block->alias_list, &super->s_object_alias); + list_add(&item->list, &block->item_list); + } + return 0; +} + +static void kill_alias(void *_block, unsigned long ignore0, + u64 ignore1, u64 ignore2, size_t ignore3) +{ + struct logfs_block *block = _block; + struct super_block *sb = block->sb; + struct logfs_super *super = logfs_super(sb); + struct object_alias_item *item; + + while (!list_empty(&block->item_list)) { + item = list_entry(block->item_list.next, typeof(*item), list); + list_del(&item->list); + mempool_free(item, super->s_alias_pool); + } + block->ops->free_block(sb, block); +} + +static int obj_type(struct inode *inode, level_t level) +{ + if (level == 0) { + if (S_ISDIR(inode->i_mode)) + return OBJ_DENTRY; + if (inode->i_ino == LOGFS_INO_MASTER) + return OBJ_INODE; + } + return OBJ_BLOCK; +} + +static int obj_len(struct super_block *sb, int obj_type) +{ + switch (obj_type) { + case OBJ_DENTRY: + return sizeof(struct logfs_disk_dentry); + case OBJ_INODE: + return sizeof(struct logfs_disk_inode); + case OBJ_BLOCK: + return sb->s_blocksize; + default: + BUG(); + } +} + +static int __logfs_segment_write(struct inode *inode, void *buf, + struct logfs_shadow *shadow, int type, int len, int compr) +{ + struct logfs_area *area; + struct super_block *sb = inode->i_sb; + s64 ofs; + struct logfs_object_header h; + int acc_len; + + if (shadow->gc_level == 0) + acc_len = len; + else + acc_len = obj_len(sb, type); + + area = get_area(sb, shadow->gc_level); + ofs = logfs_get_free_bytes(area, len + LOGFS_OBJECT_HEADERSIZE); + LOGFS_BUG_ON(ofs <= 0, sb); + /* + * Order is important. logfs_get_free_bytes(), by modifying the + * segment file, may modify the content of the very page we're about + * to write now. Which is fine, as long as the calculated crc and + * written data still match. So do the modifications _before_ + * calculating the crc. + */ + + h.len = cpu_to_be16(len); + h.type = type; + h.compr = compr; + h.ino = cpu_to_be64(inode->i_ino); + h.bix = cpu_to_be64(shadow->bix); + h.crc = logfs_crc32(&h, sizeof(h) - 4, 4); + h.data_crc = logfs_crc32(buf, len, 0); + + logfs_buf_write(area, ofs, &h, sizeof(h)); + logfs_buf_write(area, ofs + LOGFS_OBJECT_HEADERSIZE, buf, len); + + shadow->new_ofs = ofs; + shadow->new_len = acc_len + LOGFS_OBJECT_HEADERSIZE; + + return 0; +} + +static s64 logfs_segment_write_compress(struct inode *inode, void *buf, + struct logfs_shadow *shadow, int type, int len) +{ + struct super_block *sb = inode->i_sb; + void *compressor_buf = logfs_super(sb)->s_compressed_je; + ssize_t compr_len; + int ret; + + mutex_lock(&logfs_super(sb)->s_journal_mutex); + compr_len = logfs_compress(buf, compressor_buf, len, len); + + if (compr_len >= 0) { + ret = __logfs_segment_write(inode, compressor_buf, shadow, + type, compr_len, COMPR_ZLIB); + } else { + ret = __logfs_segment_write(inode, buf, shadow, type, len, + COMPR_NONE); + } + mutex_unlock(&logfs_super(sb)->s_journal_mutex); + return ret; +} + +/** + * logfs_segment_write - write data block to object store + * @inode: inode containing data + * + * Returns an errno or zero. + */ +int logfs_segment_write(struct inode *inode, struct page *page, + struct logfs_shadow *shadow) +{ + struct super_block *sb = inode->i_sb; + struct logfs_super *super = logfs_super(sb); + int do_compress, type, len; + int ret; + void *buf; + + BUG_ON(logfs_super(sb)->s_flags & LOGFS_SB_FLAG_SHUTDOWN); + do_compress = logfs_inode(inode)->li_flags & LOGFS_IF_COMPRESSED; + if (shadow->gc_level != 0) { + /* temporarily disable compression for indirect blocks */ + do_compress = 0; + } + + type = obj_type(inode, shrink_level(shadow->gc_level)); + len = obj_len(sb, type); + buf = kmap(page); + if (do_compress) + ret = logfs_segment_write_compress(inode, buf, shadow, type, + len); + else + ret = __logfs_segment_write(inode, buf, shadow, type, len, + COMPR_NONE); + kunmap(page); + + log_segment("logfs_segment_write(%llx, %llx, %x) %llx->%llx %x->%x\n", + shadow->ino, shadow->bix, shadow->gc_level, + shadow->old_ofs, shadow->new_ofs, + shadow->old_len, shadow->new_len); + /* this BUG_ON did catch a locking bug. useful */ + BUG_ON(!(shadow->new_ofs & (super->s_segsize - 1))); + return ret; +} + +int wbuf_read(struct super_block *sb, u64 ofs, size_t len, void *buf) +{ + pgoff_t index = ofs >> PAGE_SHIFT; + struct page *page; + long offset = ofs & (PAGE_SIZE-1); + long copylen; + + while (len) { + copylen = min((ulong)len, PAGE_SIZE - offset); + + page = get_mapping_page(sb, index, 1); + if (IS_ERR(page)) + return PTR_ERR(page); + memcpy(buf, page_address(page) + offset, copylen); + page_cache_release(page); + + buf += copylen; + len -= copylen; + offset = 0; + index++; + } + return 0; +} + +/* + * The "position" of indirect blocks is ambiguous. It can be the position + * of any data block somewhere behind this indirect block. So we need to + * normalize the positions through logfs_block_mask() before comparing. + */ +static int check_pos(struct super_block *sb, u64 pos1, u64 pos2, level_t level) +{ + return (pos1 & logfs_block_mask(sb, level)) != + (pos2 & logfs_block_mask(sb, level)); +} + +#if 0 +static int read_seg_header(struct super_block *sb, u64 ofs, + struct logfs_segment_header *sh) +{ + __be32 crc; + int err; + + err = wbuf_read(sb, ofs, sizeof(*sh), sh); + if (err) + return err; + crc = logfs_crc32(sh, sizeof(*sh), 4); + if (crc != sh->crc) { + printk(KERN_ERR"LOGFS: header crc error at %llx: expected %x, " + "got %x\n", ofs, be32_to_cpu(sh->crc), + be32_to_cpu(crc)); + return -EIO; + } + return 0; +} +#endif + +static int read_obj_header(struct super_block *sb, u64 ofs, + struct logfs_object_header *oh) +{ + __be32 crc; + int err; + + err = wbuf_read(sb, ofs, sizeof(*oh), oh); + if (err) + return err; + crc = logfs_crc32(oh, sizeof(*oh) - 4, 4); + if (crc != oh->crc) { + printk(KERN_ERR"LOGFS: header crc error at %llx: expected %x, " + "got %x\n", ofs, be32_to_cpu(oh->crc), + be32_to_cpu(crc)); + return -EIO; + } + return 0; +} + +static void move_btree_to_page(struct inode *inode, struct page *page, + __be64 *data) +{ + struct super_block *sb = inode->i_sb; + struct logfs_super *super = logfs_super(sb); + struct btree_head128 *head = &super->s_object_alias_tree; + struct logfs_block *block; + struct object_alias_item *item, *next; + + if (!(super->s_flags & LOGFS_SB_FLAG_OBJ_ALIAS)) + return; + + block = btree_remove128(head, inode->i_ino, page->index); + if (!block) + return; + + log_blockmove("move_btree_to_page(%llx, %llx, %x)\n", + block->ino, block->bix, block->level); + list_for_each_entry_safe(item, next, &block->item_list, list) { + data[item->child_no] = item->val; + list_del(&item->list); + mempool_free(item, super->s_alias_pool); + } + block->page = page; + SetPagePrivate(page); + page->private = (unsigned long)block; + block->ops = &indirect_block_ops; + initialize_block_counters(page, block, data, 0); +} + +/* + * This silences a false, yet annoying gcc warning. I hate it when my editor + * jumps into bitops.h each time I recompile this file. + * TODO: Complain to gcc folks about this and upgrade compiler. + */ +static unsigned long fnb(const unsigned long *addr, + unsigned long size, unsigned long offset) +{ + return find_next_bit(addr, size, offset); +} + +void move_page_to_btree(struct page *page) +{ + struct logfs_block *block = logfs_block(page); + struct super_block *sb = block->sb; + struct logfs_super *super = logfs_super(sb); + struct object_alias_item *item; + unsigned long pos; + __be64 *child; + int err; + + if (super->s_flags & LOGFS_SB_FLAG_SHUTDOWN) { + block->ops->free_block(sb, block); + return; + } + log_blockmove("move_page_to_btree(%llx, %llx, %x)\n", + block->ino, block->bix, block->level); + super->s_flags |= LOGFS_SB_FLAG_OBJ_ALIAS; + + for (pos = 0; ; pos++) { + pos = fnb(block->alias_map, LOGFS_BLOCK_FACTOR, pos); + if (pos >= LOGFS_BLOCK_FACTOR) + break; + + item = mempool_alloc(super->s_alias_pool, GFP_NOFS); + BUG_ON(!item); /* mempool empty */ + memset(item, 0, sizeof(*item)); + + child = kmap_atomic(page, KM_USER0); + item->val = child[pos]; + kunmap_atomic(child, KM_USER0); + item->child_no = pos; + list_add(&item->list, &block->item_list); + } + block->page = NULL; + ClearPagePrivate(page); + page->private = 0; + block->ops = &btree_block_ops; + err = alias_tree_insert(block->sb, block->ino, block->bix, block->level, + block); + BUG_ON(err); /* mempool empty */ + ClearPageUptodate(page); +} + +static int __logfs_segment_read(struct inode *inode, void *buf, + u64 ofs, u64 bix, level_t level) +{ + struct super_block *sb = inode->i_sb; + void *compressor_buf = logfs_super(sb)->s_compressed_je; + struct logfs_object_header oh; + __be32 crc; + u16 len; + int err, block_len; + + block_len = obj_len(sb, obj_type(inode, level)); + err = read_obj_header(sb, ofs, &oh); + if (err) + goto out_err; + + err = -EIO; + if (be64_to_cpu(oh.ino) != inode->i_ino + || check_pos(sb, be64_to_cpu(oh.bix), bix, level)) { + printk(KERN_ERR"LOGFS: (ino, bix) don't match at %llx: " + "expected (%lx, %llx), got (%llx, %llx)\n", + ofs, inode->i_ino, bix, + be64_to_cpu(oh.ino), be64_to_cpu(oh.bix)); + goto out_err; + } + + len = be16_to_cpu(oh.len); + + switch (oh.compr) { + case COMPR_NONE: + err = wbuf_read(sb, ofs + LOGFS_OBJECT_HEADERSIZE, len, buf); + if (err) + goto out_err; + crc = logfs_crc32(buf, len, 0); + if (crc != oh.data_crc) { + printk(KERN_ERR"LOGFS: uncompressed data crc error at " + "%llx: expected %x, got %x\n", ofs, + be32_to_cpu(oh.data_crc), + be32_to_cpu(crc)); + goto out_err; + } + break; + case COMPR_ZLIB: + mutex_lock(&logfs_super(sb)->s_journal_mutex); + err = wbuf_read(sb, ofs + LOGFS_OBJECT_HEADERSIZE, len, + compressor_buf); + if (err) { + mutex_unlock(&logfs_super(sb)->s_journal_mutex); + goto out_err; + } + crc = logfs_crc32(compressor_buf, len, 0); + if (crc != oh.data_crc) { + printk(KERN_ERR"LOGFS: compressed data crc error at " + "%llx: expected %x, got %x\n", ofs, + be32_to_cpu(oh.data_crc), + be32_to_cpu(crc)); + mutex_unlock(&logfs_super(sb)->s_journal_mutex); + goto out_err; + } + err = logfs_uncompress(compressor_buf, buf, len, block_len); + mutex_unlock(&logfs_super(sb)->s_journal_mutex); + if (err) { + printk(KERN_ERR"LOGFS: uncompress error at %llx\n", ofs); + goto out_err; + } + break; + default: + LOGFS_BUG(sb); + err = -EIO; + goto out_err; + } + return 0; + +out_err: + logfs_set_ro(sb); + printk(KERN_ERR"LOGFS: device is read-only now\n"); + LOGFS_BUG(sb); + return err; +} + +/** + * logfs_segment_read - read data block from object store + * @inode: inode containing data + * @buf: data buffer + * @ofs: physical data offset + * @bix: block index + * @level: block level + * + * Returns 0 on success or a negative errno. + */ +int logfs_segment_read(struct inode *inode, struct page *page, + u64 ofs, u64 bix, level_t level) +{ + int err; + void *buf; + + if (PageUptodate(page)) + return 0; + + ofs &= ~LOGFS_FULLY_POPULATED; + + buf = kmap(page); + err = __logfs_segment_read(inode, buf, ofs, bix, level); + if (!err) { + move_btree_to_page(inode, page, buf); + SetPageUptodate(page); + } + kunmap(page); + log_segment("logfs_segment_read(%lx, %llx, %x) %llx (%d)\n", + inode->i_ino, bix, level, ofs, err); + return err; +} + +int logfs_segment_delete(struct inode *inode, struct logfs_shadow *shadow) +{ + struct super_block *sb = inode->i_sb; + struct logfs_object_header h; + u16 len; + int err; + + BUG_ON(logfs_super(sb)->s_flags & LOGFS_SB_FLAG_SHUTDOWN); + BUG_ON(shadow->old_ofs & LOGFS_FULLY_POPULATED); + if (!shadow->old_ofs) + return 0; + + log_segment("logfs_segment_delete(%llx, %llx, %x) %llx->%llx %x->%x\n", + shadow->ino, shadow->bix, shadow->gc_level, + shadow->old_ofs, shadow->new_ofs, + shadow->old_len, shadow->new_len); + err = read_obj_header(sb, shadow->old_ofs, &h); + LOGFS_BUG_ON(err, sb); + LOGFS_BUG_ON(be64_to_cpu(h.ino) != inode->i_ino, sb); + LOGFS_BUG_ON(check_pos(sb, shadow->bix, be64_to_cpu(h.bix), + shrink_level(shadow->gc_level)), sb); + + if (shadow->gc_level == 0) + len = be16_to_cpu(h.len); + else + len = obj_len(sb, h.type); + shadow->old_len = len + sizeof(h); + return 0; +} + +static void freeseg(struct super_block *sb, u32 segno) +{ + struct logfs_super *super = logfs_super(sb); + struct address_space *mapping = super->s_mapping_inode->i_mapping; + struct page *page; + u64 ofs, start, end; + + start = dev_ofs(sb, segno, 0); + end = dev_ofs(sb, segno + 1, 0); + for (ofs = start; ofs < end; ofs += PAGE_SIZE) { + page = find_get_page(mapping, ofs >> PAGE_SHIFT); + if (!page) + continue; + ClearPagePrivate(page); + page_cache_release(page); + } +} + +int logfs_open_area(struct logfs_area *area, size_t bytes) +{ + struct super_block *sb = area->a_sb; + struct logfs_super *super = logfs_super(sb); + int err, closed = 0; + + if (area->a_is_open && area->a_used_bytes + bytes <= super->s_segsize) + return 0; + + if (area->a_is_open) { + u64 ofs = dev_ofs(sb, area->a_segno, area->a_written_bytes); + u32 len = super->s_segsize - area->a_written_bytes; + + log_gc("logfs_close_area(%x)\n", area->a_segno); + pad_wbuf(area, 1); + super->s_devops->writeseg(area->a_sb, ofs, len); + freeseg(sb, area->a_segno); + closed = 1; + } + + area->a_used_bytes = 0; + area->a_written_bytes = 0; +again: + area->a_ops->get_free_segment(area); + area->a_ops->get_erase_count(area); + + log_gc("logfs_open_area(%x, %x)\n", area->a_segno, area->a_level); + err = area->a_ops->erase_segment(area); + if (err) { + printk(KERN_WARNING "LogFS: Error erasing segment %x\n", + area->a_segno); + logfs_mark_segment_bad(sb, area->a_segno); + goto again; + } + area->a_is_open = 1; + return closed; +} + +void logfs_sync_area(struct logfs_area *area) +{ + struct super_block *sb = area->a_sb; + struct logfs_super *super = logfs_super(sb); + u64 ofs = dev_ofs(sb, area->a_segno, area->a_written_bytes); + u32 len = (area->a_used_bytes - area->a_written_bytes); + + if (super->s_writesize) + len &= ~(super->s_writesize - 1); + if (len == 0) + return; + pad_wbuf(area, 0); + super->s_devops->writeseg(sb, ofs, len); + area->a_written_bytes += len; +} + +void logfs_sync_segments(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + int i; + + for_each_area(i) + logfs_sync_area(super->s_area[i]); +} + +/* + * Pick a free segment to be used for this area. Effectively takes a + * candidate from the free list (not really a candidate anymore). + */ +static void ostore_get_free_segment(struct logfs_area *area) +{ + struct super_block *sb = area->a_sb; + struct logfs_super *super = logfs_super(sb); + + if (super->s_free_list.count == 0) { + printk(KERN_ERR"LOGFS: ran out of free segments\n"); + LOGFS_BUG(sb); + } + + area->a_segno = get_best_cand(sb, &super->s_free_list, NULL); +} + +static void ostore_get_erase_count(struct logfs_area *area) +{ + struct logfs_segment_entry se; + u32 ec_level; + + logfs_get_segment_entry(area->a_sb, area->a_segno, &se); + BUG_ON(se.ec_level == cpu_to_be32(BADSEG) || + se.valid == cpu_to_be32(RESERVED)); + + ec_level = be32_to_cpu(se.ec_level); + area->a_erase_count = (ec_level >> 4) + 1; +} + +static int ostore_erase_segment(struct logfs_area *area) +{ + struct super_block *sb = area->a_sb; + struct logfs_segment_header sh; + u64 ofs; + int err; + + err = logfs_erase_segment(sb, area->a_segno); + if (err) + return err; + + sh.pad = 0; + sh.type = SEG_OSTORE; + sh.level = (__force u8)area->a_level; + sh.segno = cpu_to_be32(area->a_segno); + sh.ec = cpu_to_be32(area->a_erase_count); + sh.gec = cpu_to_be64(logfs_super(sb)->s_gec); + sh.crc = logfs_crc32(&sh, sizeof(sh), 4); + + logfs_set_segment_erased(sb, area->a_segno, area->a_erase_count, + area->a_level); + + ofs = dev_ofs(sb, area->a_segno, 0); + area->a_used_bytes = sizeof(sh); + logfs_buf_write(area, ofs, &sh, sizeof(sh)); + return 0; +} + +static const struct logfs_area_ops ostore_area_ops = { + .get_free_segment = ostore_get_free_segment, + .get_erase_count = ostore_get_erase_count, + .erase_segment = ostore_erase_segment, +}; + +static void free_area(struct logfs_area *area) +{ + if (area) + freeseg(area->a_sb, area->a_segno); + kfree(area); +} + +static struct logfs_area *alloc_area(struct super_block *sb) +{ + struct logfs_area *area; + + area = kzalloc(sizeof(*area), GFP_KERNEL); + if (!area) + return NULL; + + area->a_sb = sb; + return area; +} + +static void map_invalidatepage(struct page *page, unsigned long l) +{ + BUG(); +} + +static int map_releasepage(struct page *page, gfp_t g) +{ + /* Don't release these pages */ + return 0; +} + +static const struct address_space_operations mapping_aops = { + .invalidatepage = map_invalidatepage, + .releasepage = map_releasepage, + .set_page_dirty = __set_page_dirty_nobuffers, +}; + +int logfs_init_mapping(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + struct address_space *mapping; + struct inode *inode; + + inode = logfs_new_meta_inode(sb, LOGFS_INO_MAPPING); + if (IS_ERR(inode)) + return PTR_ERR(inode); + super->s_mapping_inode = inode; + mapping = inode->i_mapping; + mapping->a_ops = &mapping_aops; + /* Would it be possible to use __GFP_HIGHMEM as well? */ + mapping_set_gfp_mask(mapping, GFP_NOFS); + return 0; +} + +int logfs_init_areas(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + int i = -1; + + super->s_alias_pool = mempool_create_kmalloc_pool(600, + sizeof(struct object_alias_item)); + if (!super->s_alias_pool) + return -ENOMEM; + + super->s_journal_area = alloc_area(sb); + if (!super->s_journal_area) + goto err; + + for_each_area(i) { + super->s_area[i] = alloc_area(sb); + if (!super->s_area[i]) + goto err; + super->s_area[i]->a_level = GC_LEVEL(i); + super->s_area[i]->a_ops = &ostore_area_ops; + } + btree_init_mempool128(&super->s_object_alias_tree, + super->s_btree_pool); + return 0; + +err: + for (i--; i >= 0; i--) + free_area(super->s_area[i]); + free_area(super->s_journal_area); + mempool_destroy(super->s_alias_pool); + return -ENOMEM; +} + +void logfs_cleanup_areas(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + int i; + + btree_grim_visitor128(&super->s_object_alias_tree, 0, kill_alias); + for_each_area(i) + free_area(super->s_area[i]); + free_area(super->s_journal_area); + destroy_meta_inode(super->s_mapping_inode); +} diff --git a/fs/logfs/super.c b/fs/logfs/super.c new file mode 100644 index 00000000000..d128a2c1c8d --- /dev/null +++ b/fs/logfs/super.c @@ -0,0 +1,634 @@ +/* + * fs/logfs/super.c + * + * As should be obvious for Linux kernel code, license is GPLv2 + * + * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org> + * + * Generally contains mount/umount code and also serves as a dump area for + * any functions that don't fit elsewhere and neither justify a file of their + * own. + */ +#include "logfs.h" +#include <linux/bio.h> +#include <linux/mtd/mtd.h> +#include <linux/statfs.h> +#include <linux/buffer_head.h> + +static DEFINE_MUTEX(emergency_mutex); +static struct page *emergency_page; + +struct page *emergency_read_begin(struct address_space *mapping, pgoff_t index) +{ + filler_t *filler = (filler_t *)mapping->a_ops->readpage; + struct page *page; + int err; + + page = read_cache_page(mapping, index, filler, NULL); + if (page) + return page; + + /* No more pages available, switch to emergency page */ + printk(KERN_INFO"Logfs: Using emergency page\n"); + mutex_lock(&emergency_mutex); + err = filler(NULL, emergency_page); + if (err) { + mutex_unlock(&emergency_mutex); + printk(KERN_EMERG"Logfs: Error reading emergency page\n"); + return ERR_PTR(err); + } + return emergency_page; +} + +void emergency_read_end(struct page *page) +{ + if (page == emergency_page) + mutex_unlock(&emergency_mutex); + else + page_cache_release(page); +} + +static void dump_segfile(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + struct logfs_segment_entry se; + u32 segno; + + for (segno = 0; segno < super->s_no_segs; segno++) { + logfs_get_segment_entry(sb, segno, &se); + printk("%3x: %6x %8x", segno, be32_to_cpu(se.ec_level), + be32_to_cpu(se.valid)); + if (++segno < super->s_no_segs) { + logfs_get_segment_entry(sb, segno, &se); + printk(" %6x %8x", be32_to_cpu(se.ec_level), + be32_to_cpu(se.valid)); + } + if (++segno < super->s_no_segs) { + logfs_get_segment_entry(sb, segno, &se); + printk(" %6x %8x", be32_to_cpu(se.ec_level), + be32_to_cpu(se.valid)); + } + if (++segno < super->s_no_segs) { + logfs_get_segment_entry(sb, segno, &se); + printk(" %6x %8x", be32_to_cpu(se.ec_level), + be32_to_cpu(se.valid)); + } + printk("\n"); + } +} + +/* + * logfs_crash_dump - dump debug information to device + * + * The LogFS superblock only occupies part of a segment. This function will + * write as much debug information as it can gather into the spare space. + */ +void logfs_crash_dump(struct super_block *sb) +{ + dump_segfile(sb); +} + +/* + * TODO: move to lib/string.c + */ +/** + * memchr_inv - Find a character in an area of memory. + * @s: The memory area + * @c: The byte to search for + * @n: The size of the area. + * + * returns the address of the first character other than @c, or %NULL + * if the whole buffer contains just @c. + */ +void *memchr_inv(const void *s, int c, size_t n) +{ + const unsigned char *p = s; + while (n-- != 0) + if ((unsigned char)c != *p++) + return (void *)(p - 1); + + return NULL; +} + +/* + * FIXME: There should be a reserve for root, similar to ext2. + */ +int logfs_statfs(struct dentry *dentry, struct kstatfs *stats) +{ + struct super_block *sb = dentry->d_sb; + struct logfs_super *super = logfs_super(sb); + + stats->f_type = LOGFS_MAGIC_U32; + stats->f_bsize = sb->s_blocksize; + stats->f_blocks = super->s_size >> LOGFS_BLOCK_BITS >> 3; + stats->f_bfree = super->s_free_bytes >> sb->s_blocksize_bits; + stats->f_bavail = super->s_free_bytes >> sb->s_blocksize_bits; + stats->f_files = 0; + stats->f_ffree = 0; + stats->f_namelen = LOGFS_MAX_NAMELEN; + return 0; +} + +static int logfs_sb_set(struct super_block *sb, void *_super) +{ + struct logfs_super *super = _super; + + sb->s_fs_info = super; + sb->s_mtd = super->s_mtd; + sb->s_bdev = super->s_bdev; + return 0; +} + +static int logfs_sb_test(struct super_block *sb, void *_super) +{ + struct logfs_super *super = _super; + struct mtd_info *mtd = super->s_mtd; + + if (mtd && sb->s_mtd == mtd) + return 1; + if (super->s_bdev && sb->s_bdev == super->s_bdev) + return 1; + return 0; +} + +static void set_segment_header(struct logfs_segment_header *sh, u8 type, + u8 level, u32 segno, u32 ec) +{ + sh->pad = 0; + sh->type = type; + sh->level = level; + sh->segno = cpu_to_be32(segno); + sh->ec = cpu_to_be32(ec); + sh->gec = cpu_to_be64(segno); + sh->crc = logfs_crc32(sh, LOGFS_SEGMENT_HEADERSIZE, 4); +} + +static void logfs_write_ds(struct super_block *sb, struct logfs_disk_super *ds, + u32 segno, u32 ec) +{ + struct logfs_super *super = logfs_super(sb); + struct logfs_segment_header *sh = &ds->ds_sh; + int i; + + memset(ds, 0, sizeof(*ds)); + set_segment_header(sh, SEG_SUPER, 0, segno, ec); + + ds->ds_ifile_levels = super->s_ifile_levels; + ds->ds_iblock_levels = super->s_iblock_levels; + ds->ds_data_levels = super->s_data_levels; /* XXX: Remove */ + ds->ds_segment_shift = super->s_segshift; + ds->ds_block_shift = sb->s_blocksize_bits; + ds->ds_write_shift = super->s_writeshift; + ds->ds_filesystem_size = cpu_to_be64(super->s_size); + ds->ds_segment_size = cpu_to_be32(super->s_segsize); + ds->ds_bad_seg_reserve = cpu_to_be32(super->s_bad_seg_reserve); + ds->ds_feature_incompat = cpu_to_be64(super->s_feature_incompat); + ds->ds_feature_ro_compat= cpu_to_be64(super->s_feature_ro_compat); + ds->ds_feature_compat = cpu_to_be64(super->s_feature_compat); + ds->ds_feature_flags = cpu_to_be64(super->s_feature_flags); + ds->ds_root_reserve = cpu_to_be64(super->s_root_reserve); + ds->ds_speed_reserve = cpu_to_be64(super->s_speed_reserve); + journal_for_each(i) + ds->ds_journal_seg[i] = cpu_to_be32(super->s_journal_seg[i]); + ds->ds_magic = cpu_to_be64(LOGFS_MAGIC); + ds->ds_crc = logfs_crc32(ds, sizeof(*ds), + LOGFS_SEGMENT_HEADERSIZE + 12); +} + +static int write_one_sb(struct super_block *sb, + struct page *(*find_sb)(struct super_block *sb, u64 *ofs)) +{ + struct logfs_super *super = logfs_super(sb); + struct logfs_disk_super *ds; + struct logfs_segment_entry se; + struct page *page; + u64 ofs; + u32 ec, segno; + int err; + + page = find_sb(sb, &ofs); + if (!page) + return -EIO; + ds = page_address(page); + segno = seg_no(sb, ofs); + logfs_get_segment_entry(sb, segno, &se); + ec = be32_to_cpu(se.ec_level) >> 4; + ec++; + logfs_set_segment_erased(sb, segno, ec, 0); + logfs_write_ds(sb, ds, segno, ec); + err = super->s_devops->write_sb(sb, page); + page_cache_release(page); + return err; +} + +int logfs_write_sb(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + int err; + + /* First superblock */ + err = write_one_sb(sb, super->s_devops->find_first_sb); + if (err) + return err; + + /* Last superblock */ + err = write_one_sb(sb, super->s_devops->find_last_sb); + if (err) + return err; + return 0; +} + +static int ds_cmp(const void *ds0, const void *ds1) +{ + size_t len = sizeof(struct logfs_disk_super); + + /* We know the segment headers differ, so ignore them */ + len -= LOGFS_SEGMENT_HEADERSIZE; + ds0 += LOGFS_SEGMENT_HEADERSIZE; + ds1 += LOGFS_SEGMENT_HEADERSIZE; + return memcmp(ds0, ds1, len); +} + +static int logfs_recover_sb(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + struct logfs_disk_super _ds0, *ds0 = &_ds0; + struct logfs_disk_super _ds1, *ds1 = &_ds1; + int err, valid0, valid1; + + /* read first superblock */ + err = wbuf_read(sb, super->s_sb_ofs[0], sizeof(*ds0), ds0); + if (err) + return err; + /* read last superblock */ + err = wbuf_read(sb, super->s_sb_ofs[1], sizeof(*ds1), ds1); + if (err) + return err; + valid0 = logfs_check_ds(ds0) == 0; + valid1 = logfs_check_ds(ds1) == 0; + + if (!valid0 && valid1) { + printk(KERN_INFO"First superblock is invalid - fixing.\n"); + return write_one_sb(sb, super->s_devops->find_first_sb); + } + if (valid0 && !valid1) { + printk(KERN_INFO"Last superblock is invalid - fixing.\n"); + return write_one_sb(sb, super->s_devops->find_last_sb); + } + if (valid0 && valid1 && ds_cmp(ds0, ds1)) { + printk(KERN_INFO"Superblocks don't match - fixing.\n"); + return write_one_sb(sb, super->s_devops->find_last_sb); + } + /* If neither is valid now, something's wrong. Didn't we properly + * check them before?!? */ + BUG_ON(!valid0 && !valid1); + return 0; +} + +static int logfs_make_writeable(struct super_block *sb) +{ + int err; + + /* Repair any broken superblock copies */ + err = logfs_recover_sb(sb); + if (err) + return err; + + /* Check areas for trailing unaccounted data */ + err = logfs_check_areas(sb); + if (err) + return err; + + err = logfs_open_segfile(sb); + if (err) + return err; + + /* Do one GC pass before any data gets dirtied */ + logfs_gc_pass(sb); + + /* after all initializations are done, replay the journal + * for rw-mounts, if necessary */ + err = logfs_replay_journal(sb); + if (err) + return err; + + return 0; +} + +static int logfs_get_sb_final(struct super_block *sb, struct vfsmount *mnt) +{ + struct inode *rootdir; + int err; + + /* root dir */ + rootdir = logfs_iget(sb, LOGFS_INO_ROOT); + if (IS_ERR(rootdir)) + goto fail; + + sb->s_root = d_alloc_root(rootdir); + if (!sb->s_root) + goto fail; + + /* FIXME: check for read-only mounts */ + err = logfs_make_writeable(sb); + if (err) + goto fail2; + + log_super("LogFS: Finished mounting\n"); + simple_set_mnt(mnt, sb); + return 0; + +fail2: + iput(rootdir); +fail: + iput(logfs_super(sb)->s_master_inode); + return -EIO; +} + +int logfs_check_ds(struct logfs_disk_super *ds) +{ + struct logfs_segment_header *sh = &ds->ds_sh; + + if (ds->ds_magic != cpu_to_be64(LOGFS_MAGIC)) + return -EINVAL; + if (sh->crc != logfs_crc32(sh, LOGFS_SEGMENT_HEADERSIZE, 4)) + return -EINVAL; + if (ds->ds_crc != logfs_crc32(ds, sizeof(*ds), + LOGFS_SEGMENT_HEADERSIZE + 12)) + return -EINVAL; + return 0; +} + +static struct page *find_super_block(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + struct page *first, *last; + + first = super->s_devops->find_first_sb(sb, &super->s_sb_ofs[0]); + if (!first || IS_ERR(first)) + return NULL; + last = super->s_devops->find_last_sb(sb, &super->s_sb_ofs[1]); + if (!last || IS_ERR(first)) { + page_cache_release(first); + return NULL; + } + + if (!logfs_check_ds(page_address(first))) { + page_cache_release(last); + return first; + } + + /* First one didn't work, try the second superblock */ + if (!logfs_check_ds(page_address(last))) { + page_cache_release(first); + return last; + } + + /* Neither worked, sorry folks */ + page_cache_release(first); + page_cache_release(last); + return NULL; +} + +static int __logfs_read_sb(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + struct page *page; + struct logfs_disk_super *ds; + int i; + + page = find_super_block(sb); + if (!page) + return -EIO; + + ds = page_address(page); + super->s_size = be64_to_cpu(ds->ds_filesystem_size); + super->s_root_reserve = be64_to_cpu(ds->ds_root_reserve); + super->s_speed_reserve = be64_to_cpu(ds->ds_speed_reserve); + super->s_bad_seg_reserve = be32_to_cpu(ds->ds_bad_seg_reserve); + super->s_segsize = 1 << ds->ds_segment_shift; + super->s_segmask = (1 << ds->ds_segment_shift) - 1; + super->s_segshift = ds->ds_segment_shift; + sb->s_blocksize = 1 << ds->ds_block_shift; + sb->s_blocksize_bits = ds->ds_block_shift; + super->s_writesize = 1 << ds->ds_write_shift; + super->s_writeshift = ds->ds_write_shift; + super->s_no_segs = super->s_size >> super->s_segshift; + super->s_no_blocks = super->s_segsize >> sb->s_blocksize_bits; + super->s_feature_incompat = be64_to_cpu(ds->ds_feature_incompat); + super->s_feature_ro_compat = be64_to_cpu(ds->ds_feature_ro_compat); + super->s_feature_compat = be64_to_cpu(ds->ds_feature_compat); + super->s_feature_flags = be64_to_cpu(ds->ds_feature_flags); + + journal_for_each(i) + super->s_journal_seg[i] = be32_to_cpu(ds->ds_journal_seg[i]); + + super->s_ifile_levels = ds->ds_ifile_levels; + super->s_iblock_levels = ds->ds_iblock_levels; + super->s_data_levels = ds->ds_data_levels; + super->s_total_levels = super->s_ifile_levels + super->s_iblock_levels + + super->s_data_levels; + page_cache_release(page); + return 0; +} + +static int logfs_read_sb(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + int ret; + + super->s_btree_pool = mempool_create(32, btree_alloc, btree_free, NULL); + if (!super->s_btree_pool) + return -ENOMEM; + + btree_init_mempool64(&super->s_shadow_tree.new, super->s_btree_pool); + btree_init_mempool64(&super->s_shadow_tree.old, super->s_btree_pool); + + ret = logfs_init_mapping(sb); + if (ret) + return ret; + + ret = __logfs_read_sb(sb); + if (ret) + return ret; + + mutex_init(&super->s_dirop_mutex); + mutex_init(&super->s_object_alias_mutex); + INIT_LIST_HEAD(&super->s_freeing_list); + + ret = logfs_init_rw(sb); + if (ret) + return ret; + + ret = logfs_init_areas(sb); + if (ret) + return ret; + + ret = logfs_init_gc(sb); + if (ret) + return ret; + + ret = logfs_init_journal(sb); + if (ret) + return ret; + + return 0; +} + +static void logfs_kill_sb(struct super_block *sb) +{ + struct logfs_super *super = logfs_super(sb); + + log_super("LogFS: Start unmounting\n"); + /* Alias entries slow down mount, so evict as many as possible */ + sync_filesystem(sb); + logfs_write_anchor(super->s_master_inode); + + /* + * From this point on alias entries are simply dropped - and any + * writes to the object store are considered bugs. + */ + super->s_flags |= LOGFS_SB_FLAG_SHUTDOWN; + log_super("LogFS: Now in shutdown\n"); + generic_shutdown_super(sb); + + BUG_ON(super->s_dirty_used_bytes || super->s_dirty_free_bytes); + + logfs_cleanup_gc(sb); + logfs_cleanup_journal(sb); + logfs_cleanup_areas(sb); + logfs_cleanup_rw(sb); + super->s_devops->put_device(sb); + mempool_destroy(super->s_btree_pool); + mempool_destroy(super->s_alias_pool); + kfree(super); + log_super("LogFS: Finished unmounting\n"); +} + +int logfs_get_sb_device(struct file_system_type *type, int flags, + struct mtd_info *mtd, struct block_device *bdev, + const struct logfs_device_ops *devops, struct vfsmount *mnt) +{ + struct logfs_super *super; + struct super_block *sb; + int err = -ENOMEM; + static int mount_count; + + log_super("LogFS: Start mount %x\n", mount_count++); + super = kzalloc(sizeof(*super), GFP_KERNEL); + if (!super) + goto err0; + + super->s_mtd = mtd; + super->s_bdev = bdev; + err = -EINVAL; + sb = sget(type, logfs_sb_test, logfs_sb_set, super); + if (IS_ERR(sb)) + goto err0; + + if (sb->s_root) { + /* Device is already in use */ + err = 0; + simple_set_mnt(mnt, sb); + goto err0; + } + + super->s_devops = devops; + + /* + * sb->s_maxbytes is limited to 8TB. On 32bit systems, the page cache + * only covers 16TB and the upper 8TB are used for indirect blocks. + * On 64bit system we could bump up the limit, but that would make + * the filesystem incompatible with 32bit systems. + */ + sb->s_maxbytes = (1ull << 43) - 1; + sb->s_op = &logfs_super_operations; + sb->s_flags = flags | MS_NOATIME; + + err = logfs_read_sb(sb); + if (err) + goto err1; + + sb->s_flags |= MS_ACTIVE; + err = logfs_get_sb_final(sb, mnt); + if (err) + goto err1; + return 0; + +err1: + up_write(&sb->s_umount); + deactivate_super(sb); + return err; +err0: + kfree(super); + //devops->put_device(sb); + return err; +} + +static int logfs_get_sb(struct file_system_type *type, int flags, + const char *devname, void *data, struct vfsmount *mnt) +{ + ulong mtdnr; + + if (!devname) + return logfs_get_sb_bdev(type, flags, devname, mnt); + if (strncmp(devname, "mtd", 3)) + return logfs_get_sb_bdev(type, flags, devname, mnt); + + { + char *garbage; + mtdnr = simple_strtoul(devname+3, &garbage, 0); + if (*garbage) + return -EINVAL; + } + + return logfs_get_sb_mtd(type, flags, mtdnr, mnt); +} + +static struct file_system_type logfs_fs_type = { + .owner = THIS_MODULE, + .name = "logfs", + .get_sb = logfs_get_sb, + .kill_sb = logfs_kill_sb, + .fs_flags = FS_REQUIRES_DEV, + +}; + +static int __init logfs_init(void) +{ + int ret; + + emergency_page = alloc_pages(GFP_KERNEL, 0); + if (!emergency_page) + return -ENOMEM; + + ret = logfs_compr_init(); + if (ret) + goto out1; + + ret = logfs_init_inode_cache(); + if (ret) + goto out2; + + return register_filesystem(&logfs_fs_type); +out2: + logfs_compr_exit(); +out1: + __free_pages(emergency_page, 0); + return ret; +} + +static void __exit logfs_exit(void) +{ + unregister_filesystem(&logfs_fs_type); + logfs_destroy_inode_cache(); + logfs_compr_exit(); + __free_pages(emergency_page, 0); +} + +module_init(logfs_init); +module_exit(logfs_exit); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Joern Engel <joern@logfs.org>"); +MODULE_DESCRIPTION("scalable flash filesystem"); diff --git a/include/linux/btree-128.h b/include/linux/btree-128.h new file mode 100644 index 00000000000..0b3414c4c92 --- /dev/null +++ b/include/linux/btree-128.h @@ -0,0 +1,109 @@ +extern struct btree_geo btree_geo128; + +struct btree_head128 { struct btree_head h; }; + +static inline void btree_init_mempool128(struct btree_head128 *head, + mempool_t *mempool) +{ + btree_init_mempool(&head->h, mempool); +} + +static inline int btree_init128(struct btree_head128 *head) +{ + return btree_init(&head->h); +} + +static inline void btree_destroy128(struct btree_head128 *head) +{ + btree_destroy(&head->h); +} + +static inline void *btree_lookup128(struct btree_head128 *head, u64 k1, u64 k2) +{ + u64 key[2] = {k1, k2}; + return btree_lookup(&head->h, &btree_geo128, (unsigned long *)&key); +} + +static inline void *btree_get_prev128(struct btree_head128 *head, + u64 *k1, u64 *k2) +{ + u64 key[2] = {*k1, *k2}; + void *val; + + val = btree_get_prev(&head->h, &btree_geo128, + (unsigned long *)&key); + *k1 = key[0]; + *k2 = key[1]; + return val; +} + +static inline int btree_insert128(struct btree_head128 *head, u64 k1, u64 k2, + void *val, gfp_t gfp) +{ + u64 key[2] = {k1, k2}; + return btree_insert(&head->h, &btree_geo128, + (unsigned long *)&key, val, gfp); +} + +static inline int btree_update128(struct btree_head128 *head, u64 k1, u64 k2, + void *val) +{ + u64 key[2] = {k1, k2}; + return btree_update(&head->h, &btree_geo128, + (unsigned long *)&key, val); +} + +static inline void *btree_remove128(struct btree_head128 *head, u64 k1, u64 k2) +{ + u64 key[2] = {k1, k2}; + return btree_remove(&head->h, &btree_geo128, (unsigned long *)&key); +} + +static inline void *btree_last128(struct btree_head128 *head, u64 *k1, u64 *k2) +{ + u64 key[2]; + void *val; + + val = btree_last(&head->h, &btree_geo128, (unsigned long *)&key[0]); + if (val) { + *k1 = key[0]; + *k2 = key[1]; + } + + return val; +} + +static inline int btree_merge128(struct btree_head128 *target, + struct btree_head128 *victim, + gfp_t gfp) +{ + return btree_merge(&target->h, &victim->h, &btree_geo128, gfp); +} + +void visitor128(void *elem, unsigned long opaque, unsigned long *__key, + size_t index, void *__func); + +typedef void (*visitor128_t)(void *elem, unsigned long opaque, + u64 key1, u64 key2, size_t index); + +static inline size_t btree_visitor128(struct btree_head128 *head, + unsigned long opaque, + visitor128_t func2) +{ + return btree_visitor(&head->h, &btree_geo128, opaque, + visitor128, func2); +} + +static inline size_t btree_grim_visitor128(struct btree_head128 *head, + unsigned long opaque, + visitor128_t func2) +{ + return btree_grim_visitor(&head->h, &btree_geo128, opaque, + visitor128, func2); +} + +#define btree_for_each_safe128(head, k1, k2, val) \ + for (val = btree_last128(head, &k1, &k2); \ + val; \ + val = btree_get_prev128(head, &k1, &k2)) + diff --git a/include/linux/btree-type.h b/include/linux/btree-type.h new file mode 100644 index 00000000000..9a1147ef856 --- /dev/null +++ b/include/linux/btree-type.h @@ -0,0 +1,147 @@ +#define __BTREE_TP(pfx, type, sfx) pfx ## type ## sfx +#define _BTREE_TP(pfx, type, sfx) __BTREE_TP(pfx, type, sfx) +#define BTREE_TP(pfx) _BTREE_TP(pfx, BTREE_TYPE_SUFFIX,) +#define BTREE_FN(name) BTREE_TP(btree_ ## name) +#define BTREE_TYPE_HEAD BTREE_TP(struct btree_head) +#define VISITOR_FN BTREE_TP(visitor) +#define VISITOR_FN_T _BTREE_TP(visitor, BTREE_TYPE_SUFFIX, _t) + +BTREE_TYPE_HEAD { + struct btree_head h; +}; + +static inline void BTREE_FN(init_mempool)(BTREE_TYPE_HEAD *head, + mempool_t *mempool) +{ + btree_init_mempool(&head->h, mempool); +} + +static inline int BTREE_FN(init)(BTREE_TYPE_HEAD *head) +{ + return btree_init(&head->h); +} + +static inline void BTREE_FN(destroy)(BTREE_TYPE_HEAD *head) +{ + btree_destroy(&head->h); +} + +static inline int BTREE_FN(merge)(BTREE_TYPE_HEAD *target, + BTREE_TYPE_HEAD *victim, + gfp_t gfp) +{ + return btree_merge(&target->h, &victim->h, BTREE_TYPE_GEO, gfp); +} + +#if (BITS_PER_LONG > BTREE_TYPE_BITS) +static inline void *BTREE_FN(lookup)(BTREE_TYPE_HEAD *head, BTREE_KEYTYPE key) +{ + unsigned long _key = key; + return btree_lookup(&head->h, BTREE_TYPE_GEO, &_key); +} + +static inline int BTREE_FN(insert)(BTREE_TYPE_HEAD *head, BTREE_KEYTYPE key, + void *val, gfp_t gfp) +{ + unsigned long _key = key; + return btree_insert(&head->h, BTREE_TYPE_GEO, &_key, val, gfp); +} + +static inline int BTREE_FN(update)(BTREE_TYPE_HEAD *head, BTREE_KEYTYPE key, + void *val) +{ + unsigned long _key = key; + return btree_update(&head->h, BTREE_TYPE_GEO, &_key, val); +} + +static inline void *BTREE_FN(remove)(BTREE_TYPE_HEAD *head, BTREE_KEYTYPE key) +{ + unsigned long _key = key; + return btree_remove(&head->h, BTREE_TYPE_GEO, &_key); +} + +static inline void *BTREE_FN(last)(BTREE_TYPE_HEAD *head, BTREE_KEYTYPE *key) +{ + unsigned long _key; + void *val = btree_last(&head->h, BTREE_TYPE_GEO, &_key); + if (val) + *key = _key; + return val; +} + +static inline void *BTREE_FN(get_prev)(BTREE_TYPE_HEAD *head, BTREE_KEYTYPE *key) +{ + unsigned long _key = *key; + void *val = btree_get_prev(&head->h, BTREE_TYPE_GEO, &_key); + if (val) + *key = _key; + return val; +} +#else +static inline void *BTREE_FN(lookup)(BTREE_TYPE_HEAD *head, BTREE_KEYTYPE key) +{ + return btree_lookup(&head->h, BTREE_TYPE_GEO, (unsigned long *)&key); +} + +static inline int BTREE_FN(insert)(BTREE_TYPE_HEAD *head, BTREE_KEYTYPE key, + void *val, gfp_t gfp) +{ + return btree_insert(&head->h, BTREE_TYPE_GEO, (unsigned long *)&key, + val, gfp); +} + +static inline int BTREE_FN(update)(BTREE_TYPE_HEAD *head, BTREE_KEYTYPE key, + void *val) +{ + return btree_update(&head->h, BTREE_TYPE_GEO, (unsigned long *)&key, val); +} + +static inline void *BTREE_FN(remove)(BTREE_TYPE_HEAD *head, BTREE_KEYTYPE key) +{ + return btree_remove(&head->h, BTREE_TYPE_GEO, (unsigned long *)&key); +} + +static inline void *BTREE_FN(last)(BTREE_TYPE_HEAD *head, BTREE_KEYTYPE *key) +{ + return btree_last(&head->h, BTREE_TYPE_GEO, (unsigned long *)key); +} + +static inline void *BTREE_FN(get_prev)(BTREE_TYPE_HEAD *head, BTREE_KEYTYPE *key) +{ + return btree_get_prev(&head->h, BTREE_TYPE_GEO, (unsigned long *)key); +} +#endif + +void VISITOR_FN(void *elem, unsigned long opaque, unsigned long *key, + size_t index, void *__func); + +typedef void (*VISITOR_FN_T)(void *elem, unsigned long opaque, + BTREE_KEYTYPE key, size_t index); + +static inline size_t BTREE_FN(visitor)(BTREE_TYPE_HEAD *head, + unsigned long opaque, + VISITOR_FN_T func2) +{ + return btree_visitor(&head->h, BTREE_TYPE_GEO, opaque, + visitorl, func2); +} + +static inline size_t BTREE_FN(grim_visitor)(BTREE_TYPE_HEAD *head, + unsigned long opaque, + VISITOR_FN_T func2) +{ + return btree_grim_visitor(&head->h, BTREE_TYPE_GEO, opaque, + visitorl, func2); +} + +#undef VISITOR_FN +#undef VISITOR_FN_T +#undef __BTREE_TP +#undef _BTREE_TP +#undef BTREE_TP +#undef BTREE_FN +#undef BTREE_TYPE_HEAD +#undef BTREE_TYPE_SUFFIX +#undef BTREE_TYPE_GEO +#undef BTREE_KEYTYPE +#undef BTREE_TYPE_BITS diff --git a/include/linux/btree.h b/include/linux/btree.h new file mode 100644 index 00000000000..65b5bb05832 --- /dev/null +++ b/include/linux/btree.h @@ -0,0 +1,243 @@ +#ifndef BTREE_H +#define BTREE_H + +#include <linux/kernel.h> +#include <linux/mempool.h> + +/** + * DOC: B+Tree basics + * + * A B+Tree is a data structure for looking up arbitrary (currently allowing + * unsigned long, u32, u64 and 2 * u64) keys into pointers. The data structure + * is described at http://en.wikipedia.org/wiki/B-tree, we currently do not + * use binary search to find the key on lookups. + * + * Each B+Tree consists of a head, that contains bookkeeping information and + * a variable number (starting with zero) nodes. Each node contains the keys + * and pointers to sub-nodes, or, for leaf nodes, the keys and values for the + * tree entries. + * + * Each node in this implementation has the following layout: + * [key1, key2, ..., keyN] [val1, val2, ..., valN] + * + * Each key here is an array of unsigned longs, geo->no_longs in total. The + * number of keys and values (N) is geo->no_pairs. + */ + +/** + * struct btree_head - btree head + * + * @node: the first node in the tree + * @mempool: mempool used for node allocations + * @height: current of the tree + */ +struct btree_head { + unsigned long *node; + mempool_t *mempool; + int height; +}; + +/* btree geometry */ +struct btree_geo; + +/** + * btree_alloc - allocate function for the mempool + * @gfp_mask: gfp mask for the allocation + * @pool_data: unused + */ +void *btree_alloc(gfp_t gfp_mask, void *pool_data); + +/** + * btree_free - free function for the mempool + * @element: the element to free + * @pool_data: unused + */ +void btree_free(void *element, void *pool_data); + +/** + * btree_init_mempool - initialise a btree with given mempool + * + * @head: the btree head to initialise + * @mempool: the mempool to use + * + * When this function is used, there is no need to destroy + * the mempool. + */ +void btree_init_mempool(struct btree_head *head, mempool_t *mempool); + +/** + * btree_init - initialise a btree + * + * @head: the btree head to initialise + * + * This function allocates the memory pool that the + * btree needs. Returns zero or a negative error code + * (-%ENOMEM) when memory allocation fails. + * + */ +int __must_check btree_init(struct btree_head *head); + +/** + * btree_destroy - destroy mempool + * + * @head: the btree head to destroy + * + * This function destroys the internal memory pool, use only + * when using btree_init(), not with btree_init_mempool(). + */ +void btree_destroy(struct btree_head *head); + +/** + * btree_lookup - look up a key in the btree + * + * @head: the btree to look in + * @geo: the btree geometry + * @key: the key to look up + * + * This function returns the value for the given key, or %NULL. + */ +void *btree_lookup(struct btree_head *head, struct btree_geo *geo, + unsigned long *key); + +/** + * btree_insert - insert an entry into the btree + * + * @head: the btree to add to + * @geo: the btree geometry + * @key: the key to add (must not already be present) + * @val: the value to add (must not be %NULL) + * @gfp: allocation flags for node allocations + * + * This function returns 0 if the item could be added, or an + * error code if it failed (may fail due to memory pressure). + */ +int __must_check btree_insert(struct btree_head *head, struct btree_geo *geo, + unsigned long *key, void *val, gfp_t gfp); +/** + * btree_update - update an entry in the btree + * + * @head: the btree to update + * @geo: the btree geometry + * @key: the key to update + * @val: the value to change it to (must not be %NULL) + * + * This function returns 0 if the update was successful, or + * -%ENOENT if the key could not be found. + */ +int btree_update(struct btree_head *head, struct btree_geo *geo, + unsigned long *key, void *val); +/** + * btree_remove - remove an entry from the btree + * + * @head: the btree to update + * @geo: the btree geometry + * @key: the key to remove + * + * This function returns the removed entry, or %NULL if the key + * could not be found. + */ +void *btree_remove(struct btree_head *head, struct btree_geo *geo, + unsigned long *key); + +/** + * btree_merge - merge two btrees + * + * @target: the tree that gets all the entries + * @victim: the tree that gets merged into @target + * @geo: the btree geometry + * @gfp: allocation flags + * + * The two trees @target and @victim may not contain the same keys, + * that is a bug and triggers a BUG(). This function returns zero + * if the trees were merged successfully, and may return a failure + * when memory allocation fails, in which case both trees might have + * been partially merged, i.e. some entries have been moved from + * @victim to @target. + */ +int btree_merge(struct btree_head *target, struct btree_head *victim, + struct btree_geo *geo, gfp_t gfp); + +/** + * btree_last - get last entry in btree + * + * @head: btree head + * @geo: btree geometry + * @key: last key + * + * Returns the last entry in the btree, and sets @key to the key + * of that entry; returns NULL if the tree is empty, in that case + * key is not changed. + */ +void *btree_last(struct btree_head *head, struct btree_geo *geo, + unsigned long *key); + +/** + * btree_get_prev - get previous entry + * + * @head: btree head + * @geo: btree geometry + * @key: pointer to key + * + * The function returns the next item right before the value pointed to by + * @key, and updates @key with its key, or returns %NULL when there is no + * entry with a key smaller than the given key. + */ +void *btree_get_prev(struct btree_head *head, struct btree_geo *geo, + unsigned long *key); + + +/* internal use, use btree_visitor{l,32,64,128} */ +size_t btree_visitor(struct btree_head *head, struct btree_geo *geo, + unsigned long opaque, + void (*func)(void *elem, unsigned long opaque, + unsigned long *key, size_t index, + void *func2), + void *func2); + +/* internal use, use btree_grim_visitor{l,32,64,128} */ +size_t btree_grim_visitor(struct btree_head *head, struct btree_geo *geo, + unsigned long opaque, + void (*func)(void *elem, unsigned long opaque, + unsigned long *key, + size_t index, void *func2), + void *func2); + + +#include <linux/btree-128.h> + +extern struct btree_geo btree_geo32; +#define BTREE_TYPE_SUFFIX l +#define BTREE_TYPE_BITS BITS_PER_LONG +#define BTREE_TYPE_GEO &btree_geo32 +#define BTREE_KEYTYPE unsigned long +#include <linux/btree-type.h> + +#define btree_for_each_safel(head, key, val) \ + for (val = btree_lastl(head, &key); \ + val; \ + val = btree_get_prevl(head, &key)) + +#define BTREE_TYPE_SUFFIX 32 +#define BTREE_TYPE_BITS 32 +#define BTREE_TYPE_GEO &btree_geo32 +#define BTREE_KEYTYPE u32 +#include <linux/btree-type.h> + +#define btree_for_each_safe32(head, key, val) \ + for (val = btree_last32(head, &key); \ + val; \ + val = btree_get_prev32(head, &key)) + +extern struct btree_geo btree_geo64; +#define BTREE_TYPE_SUFFIX 64 +#define BTREE_TYPE_BITS 64 +#define BTREE_TYPE_GEO &btree_geo64 +#define BTREE_KEYTYPE u64 +#include <linux/btree-type.h> + +#define btree_for_each_safe64(head, key, val) \ + for (val = btree_last64(head, &key); \ + val; \ + val = btree_get_prev64(head, &key)) + +#endif diff --git a/lib/Kconfig b/lib/Kconfig index bb1326d3839..277fbfb233b 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -156,6 +156,9 @@ config TEXTSEARCH_BM config TEXTSEARCH_FSM tristate +config BTREE + boolean + config HAS_IOMEM boolean depends on !NO_IOMEM diff --git a/lib/Makefile b/lib/Makefile index 2e78277eff9..cff82612e98 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -41,6 +41,7 @@ lib-$(CONFIG_GENERIC_FIND_NEXT_BIT) += find_next_bit.o obj-$(CONFIG_GENERIC_FIND_LAST_BIT) += find_last_bit.o obj-$(CONFIG_GENERIC_HWEIGHT) += hweight.o obj-$(CONFIG_LOCK_KERNEL) += kernel_lock.o +obj-$(CONFIG_BTREE) += btree.o obj-$(CONFIG_DEBUG_PREEMPT) += smp_processor_id.o obj-$(CONFIG_DEBUG_LIST) += list_debug.o obj-$(CONFIG_DEBUG_OBJECTS) += debugobjects.o diff --git a/lib/btree.c b/lib/btree.c new file mode 100644 index 00000000000..41859a82021 --- /dev/null +++ b/lib/btree.c @@ -0,0 +1,797 @@ +/* + * lib/btree.c - Simple In-memory B+Tree + * + * As should be obvious for Linux kernel code, license is GPLv2 + * + * Copyright (c) 2007-2008 Joern Engel <joern@logfs.org> + * Bits and pieces stolen from Peter Zijlstra's code, which is + * Copyright 2007, Red Hat Inc. Peter Zijlstra <pzijlstr@redhat.com> + * GPLv2 + * + * see http://programming.kicks-ass.net/kernel-patches/vma_lookup/btree.patch + * + * A relatively simple B+Tree implementation. I have written it as a learning + * excercise to understand how B+Trees work. Turned out to be useful as well. + * + * B+Trees can be used similar to Linux radix trees (which don't have anything + * in common with textbook radix trees, beware). Prerequisite for them working + * well is that access to a random tree node is much faster than a large number + * of operations within each node. + * + * Disks have fulfilled the prerequisite for a long time. More recently DRAM + * has gained similar properties, as memory access times, when measured in cpu + * cycles, have increased. Cacheline sizes have increased as well, which also + * helps B+Trees. + * + * Compared to radix trees, B+Trees are more efficient when dealing with a + * sparsely populated address space. Between 25% and 50% of the memory is + * occupied with valid pointers. When densely populated, radix trees contain + * ~98% pointers - hard to beat. Very sparse radix trees contain only ~2% + * pointers. + * + * This particular implementation stores pointers identified by a long value. + * Storing NULL pointers is illegal, lookup will return NULL when no entry + * was found. + * + * A tricks was used that is not commonly found in textbooks. The lowest + * values are to the right, not to the left. All used slots within a node + * are on the left, all unused slots contain NUL values. Most operations + * simply loop once over all slots and terminate on the first NUL. + */ + +#include <linux/btree.h> +#include <linux/cache.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/module.h> + +#define MAX(a, b) ((a) > (b) ? (a) : (b)) +#define NODESIZE MAX(L1_CACHE_BYTES, 128) + +struct btree_geo { + int keylen; + int no_pairs; + int no_longs; +}; + +struct btree_geo btree_geo32 = { + .keylen = 1, + .no_pairs = NODESIZE / sizeof(long) / 2, + .no_longs = NODESIZE / sizeof(long) / 2, +}; +EXPORT_SYMBOL_GPL(btree_geo32); + +#define LONG_PER_U64 (64 / BITS_PER_LONG) +struct btree_geo btree_geo64 = { + .keylen = LONG_PER_U64, + .no_pairs = NODESIZE / sizeof(long) / (1 + LONG_PER_U64), + .no_longs = LONG_PER_U64 * (NODESIZE / sizeof(long) / (1 + LONG_PER_U64)), +}; +EXPORT_SYMBOL_GPL(btree_geo64); + +struct btree_geo btree_geo128 = { + .keylen = 2 * LONG_PER_U64, + .no_pairs = NODESIZE / sizeof(long) / (1 + 2 * LONG_PER_U64), + .no_longs = 2 * LONG_PER_U64 * (NODESIZE / sizeof(long) / (1 + 2 * LONG_PER_U64)), +}; +EXPORT_SYMBOL_GPL(btree_geo128); + +static struct kmem_cache *btree_cachep; + +void *btree_alloc(gfp_t gfp_mask, void *pool_data) +{ + return kmem_cache_alloc(btree_cachep, gfp_mask); +} +EXPORT_SYMBOL_GPL(btree_alloc); + +void btree_free(void *element, void *pool_data) +{ + kmem_cache_free(btree_cachep, element); +} +EXPORT_SYMBOL_GPL(btree_free); + +static unsigned long *btree_node_alloc(struct btree_head *head, gfp_t gfp) +{ + unsigned long *node; + + node = mempool_alloc(head->mempool, gfp); + memset(node, 0, NODESIZE); + return node; +} + +static int longcmp(const unsigned long *l1, const unsigned long *l2, size_t n) +{ + size_t i; + + for (i = 0; i < n; i++) { + if (l1[i] < l2[i]) + return -1; + if (l1[i] > l2[i]) + return 1; + } + return 0; +} + +static unsigned long *longcpy(unsigned long *dest, const unsigned long *src, + size_t n) +{ + size_t i; + + for (i = 0; i < n; i++) + dest[i] = src[i]; + return dest; +} + +static unsigned long *longset(unsigned long *s, unsigned long c, size_t n) +{ + size_t i; + + for (i = 0; i < n; i++) + s[i] = c; + return s; +} + +static void dec_key(struct btree_geo *geo, unsigned long *key) +{ + unsigned long val; + int i; + + for (i = geo->keylen - 1; i >= 0; i--) { + val = key[i]; + key[i] = val - 1; + if (val) + break; + } +} + +static unsigned long *bkey(struct btree_geo *geo, unsigned long *node, int n) +{ + return &node[n * geo->keylen]; +} + +static void *bval(struct btree_geo *geo, unsigned long *node, int n) +{ + return (void *)node[geo->no_longs + n]; +} + +static void setkey(struct btree_geo *geo, unsigned long *node, int n, + unsigned long *key) +{ + longcpy(bkey(geo, node, n), key, geo->keylen); +} + +static void setval(struct btree_geo *geo, unsigned long *node, int n, + void *val) +{ + node[geo->no_longs + n] = (unsigned long) val; +} + +static void clearpair(struct btree_geo *geo, unsigned long *node, int n) +{ + longset(bkey(geo, node, n), 0, geo->keylen); + node[geo->no_longs + n] = 0; +} + +static inline void __btree_init(struct btree_head *head) +{ + head->node = NULL; + head->height = 0; +} + +void btree_init_mempool(struct btree_head *head, mempool_t *mempool) +{ + __btree_init(head); + head->mempool = mempool; +} +EXPORT_SYMBOL_GPL(btree_init_mempool); + +int btree_init(struct btree_head *head) +{ + __btree_init(head); + head->mempool = mempool_create(0, btree_alloc, btree_free, NULL); + if (!head->mempool) + return -ENOMEM; + return 0; +} +EXPORT_SYMBOL_GPL(btree_init); + +void btree_destroy(struct btree_head *head) +{ + mempool_destroy(head->mempool); + head->mempool = NULL; +} +EXPORT_SYMBOL_GPL(btree_destroy); + +void *btree_last(struct btree_head *head, struct btree_geo *geo, + unsigned long *key) +{ + int height = head->height; + unsigned long *node = head->node; + + if (height == 0) + return NULL; + + for ( ; height > 1; height--) + node = bval(geo, node, 0); + + longcpy(key, bkey(geo, node, 0), geo->keylen); + return bval(geo, node, 0); +} +EXPORT_SYMBOL_GPL(btree_last); + +static int keycmp(struct btree_geo *geo, unsigned long *node, int pos, + unsigned long *key) +{ + return longcmp(bkey(geo, node, pos), key, geo->keylen); +} + +static int keyzero(struct btree_geo *geo, unsigned long *key) +{ + int i; + + for (i = 0; i < geo->keylen; i++) + if (key[i]) + return 0; + + return 1; +} + +void *btree_lookup(struct btree_head *head, struct btree_geo *geo, + unsigned long *key) +{ + int i, height = head->height; + unsigned long *node = head->node; + + if (height == 0) + return NULL; + + for ( ; height > 1; height--) { + for (i = 0; i < geo->no_pairs; i++) + if (keycmp(geo, node, i, key) <= 0) + break; + if (i == geo->no_pairs) + return NULL; + node = bval(geo, node, i); + if (!node) + return NULL; + } + + if (!node) + return NULL; + + for (i = 0; i < geo->no_pairs; i++) + if (keycmp(geo, node, i, key) == 0) + return bval(geo, node, i); + return NULL; +} +EXPORT_SYMBOL_GPL(btree_lookup); + +int btree_update(struct btree_head *head, struct btree_geo *geo, + unsigned long *key, void *val) +{ + int i, height = head->height; + unsigned long *node = head->node; + + if (height == 0) + return -ENOENT; + + for ( ; height > 1; height--) { + for (i = 0; i < geo->no_pairs; i++) + if (keycmp(geo, node, i, key) <= 0) + break; + if (i == geo->no_pairs) + return -ENOENT; + node = bval(geo, node, i); + if (!node) + return -ENOENT; + } + + if (!node) + return -ENOENT; + + for (i = 0; i < geo->no_pairs; i++) + if (keycmp(geo, node, i, key) == 0) { + setval(geo, node, i, val); + return 0; + } + return -ENOENT; +} +EXPORT_SYMBOL_GPL(btree_update); + +/* + * Usually this function is quite similar to normal lookup. But the key of + * a parent node may be smaller than the smallest key of all its siblings. + * In such a case we cannot just return NULL, as we have only proven that no + * key smaller than __key, but larger than this parent key exists. + * So we set __key to the parent key and retry. We have to use the smallest + * such parent key, which is the last parent key we encountered. + */ +void *btree_get_prev(struct btree_head *head, struct btree_geo *geo, + unsigned long *__key) +{ + int i, height; + unsigned long *node, *oldnode; + unsigned long *retry_key = NULL, key[geo->keylen]; + + if (keyzero(geo, __key)) + return NULL; + + if (head->height == 0) + return NULL; +retry: + longcpy(key, __key, geo->keylen); + dec_key(geo, key); + + node = head->node; + for (height = head->height ; height > 1; height--) { + for (i = 0; i < geo->no_pairs; i++) + if (keycmp(geo, node, i, key) <= 0) + break; + if (i == geo->no_pairs) + goto miss; + oldnode = node; + node = bval(geo, node, i); + if (!node) + goto miss; + retry_key = bkey(geo, oldnode, i); + } + + if (!node) + goto miss; + + for (i = 0; i < geo->no_pairs; i++) { + if (keycmp(geo, node, i, key) <= 0) { + if (bval(geo, node, i)) { + longcpy(__key, bkey(geo, node, i), geo->keylen); + return bval(geo, node, i); + } else + goto miss; + } + } +miss: + if (retry_key) { + __key = retry_key; + retry_key = NULL; + goto retry; + } + return NULL; +} + +static int getpos(struct btree_geo *geo, unsigned long *node, + unsigned long *key) +{ + int i; + + for (i = 0; i < geo->no_pairs; i++) { + if (keycmp(geo, node, i, key) <= 0) + break; + } + return i; +} + +static int getfill(struct btree_geo *geo, unsigned long *node, int start) +{ + int i; + + for (i = start; i < geo->no_pairs; i++) + if (!bval(geo, node, i)) + break; + return i; +} + +/* + * locate the correct leaf node in the btree + */ +static unsigned long *find_level(struct btree_head *head, struct btree_geo *geo, + unsigned long *key, int level) +{ + unsigned long *node = head->node; + int i, height; + + for (height = head->height; height > level; height--) { + for (i = 0; i < geo->no_pairs; i++) + if (keycmp(geo, node, i, key) <= 0) + break; + + if ((i == geo->no_pairs) || !bval(geo, node, i)) { + /* right-most key is too large, update it */ + /* FIXME: If the right-most key on higher levels is + * always zero, this wouldn't be necessary. */ + i--; + setkey(geo, node, i, key); + } + BUG_ON(i < 0); + node = bval(geo, node, i); + } + BUG_ON(!node); + return node; +} + +static int btree_grow(struct btree_head *head, struct btree_geo *geo, + gfp_t gfp) +{ + unsigned long *node; + int fill; + + node = btree_node_alloc(head, gfp); + if (!node) + return -ENOMEM; + if (head->node) { + fill = getfill(geo, head->node, 0); + setkey(geo, node, 0, bkey(geo, head->node, fill - 1)); + setval(geo, node, 0, head->node); + } + head->node = node; + head->height++; + return 0; +} + +static void btree_shrink(struct btree_head *head, struct btree_geo *geo) +{ + unsigned long *node; + int fill; + + if (head->height <= 1) + return; + + node = head->node; + fill = getfill(geo, node, 0); + BUG_ON(fill > 1); + head->node = bval(geo, node, 0); + head->height--; + mempool_free(node, head->mempool); +} + +static int btree_insert_level(struct btree_head *head, struct btree_geo *geo, + unsigned long *key, void *val, int level, + gfp_t gfp) +{ + unsigned long *node; + int i, pos, fill, err; + + BUG_ON(!val); + if (head->height < level) { + err = btree_grow(head, geo, gfp); + if (err) + return err; + } + +retry: + node = find_level(head, geo, key, level); + pos = getpos(geo, node, key); + fill = getfill(geo, node, pos); + /* two identical keys are not allowed */ + BUG_ON(pos < fill && keycmp(geo, node, pos, key) == 0); + + if (fill == geo->no_pairs) { + /* need to split node */ + unsigned long *new; + + new = btree_node_alloc(head, gfp); + if (!new) + return -ENOMEM; + err = btree_insert_level(head, geo, + bkey(geo, node, fill / 2 - 1), + new, level + 1, gfp); + if (err) { + mempool_free(new, head->mempool); + return err; + } + for (i = 0; i < fill / 2; i++) { + setkey(geo, new, i, bkey(geo, node, i)); + setval(geo, new, i, bval(geo, node, i)); + setkey(geo, node, i, bkey(geo, node, i + fill / 2)); + setval(geo, node, i, bval(geo, node, i + fill / 2)); + clearpair(geo, node, i + fill / 2); + } + if (fill & 1) { + setkey(geo, node, i, bkey(geo, node, fill - 1)); + setval(geo, node, i, bval(geo, node, fill - 1)); + clearpair(geo, node, fill - 1); + } + goto retry; + } + BUG_ON(fill >= geo->no_pairs); + + /* shift and insert */ + for (i = fill; i > pos; i--) { + setkey(geo, node, i, bkey(geo, node, i - 1)); + setval(geo, node, i, bval(geo, node, i - 1)); + } + setkey(geo, node, pos, key); + setval(geo, node, pos, val); + + return 0; +} + +int btree_insert(struct btree_head *head, struct btree_geo *geo, + unsigned long *key, void *val, gfp_t gfp) +{ + return btree_insert_level(head, geo, key, val, 1, gfp); +} +EXPORT_SYMBOL_GPL(btree_insert); + +static void *btree_remove_level(struct btree_head *head, struct btree_geo *geo, + unsigned long *key, int level); +static void merge(struct btree_head *head, struct btree_geo *geo, int level, + unsigned long *left, int lfill, + unsigned long *right, int rfill, + unsigned long *parent, int lpos) +{ + int i; + + for (i = 0; i < rfill; i++) { + /* Move all keys to the left */ + setkey(geo, left, lfill + i, bkey(geo, right, i)); + setval(geo, left, lfill + i, bval(geo, right, i)); + } + /* Exchange left and right child in parent */ + setval(geo, parent, lpos, right); + setval(geo, parent, lpos + 1, left); + /* Remove left (formerly right) child from parent */ + btree_remove_level(head, geo, bkey(geo, parent, lpos), level + 1); + mempool_free(right, head->mempool); +} + +static void rebalance(struct btree_head *head, struct btree_geo *geo, + unsigned long *key, int level, unsigned long *child, int fill) +{ + unsigned long *parent, *left = NULL, *right = NULL; + int i, no_left, no_right; + + if (fill == 0) { + /* Because we don't steal entries from a neigbour, this case + * can happen. Parent node contains a single child, this + * node, so merging with a sibling never happens. + */ + btree_remove_level(head, geo, key, level + 1); + mempool_free(child, head->mempool); + return; + } + + parent = find_level(head, geo, key, level + 1); + i = getpos(geo, parent, key); + BUG_ON(bval(geo, parent, i) != child); + + if (i > 0) { + left = bval(geo, parent, i - 1); + no_left = getfill(geo, left, 0); + if (fill + no_left <= geo->no_pairs) { + merge(head, geo, level, + left, no_left, + child, fill, + parent, i - 1); + return; + } + } + if (i + 1 < getfill(geo, parent, i)) { + right = bval(geo, parent, i + 1); + no_right = getfill(geo, right, 0); + if (fill + no_right <= geo->no_pairs) { + merge(head, geo, level, + child, fill, + right, no_right, + parent, i); + return; + } + } + /* + * We could also try to steal one entry from the left or right + * neighbor. By not doing so we changed the invariant from + * "all nodes are at least half full" to "no two neighboring + * nodes can be merged". Which means that the average fill of + * all nodes is still half or better. + */ +} + +static void *btree_remove_level(struct btree_head *head, struct btree_geo *geo, + unsigned long *key, int level) +{ + unsigned long *node; + int i, pos, fill; + void *ret; + + if (level > head->height) { + /* we recursed all the way up */ + head->height = 0; + head->node = NULL; + return NULL; + } + + node = find_level(head, geo, key, level); + pos = getpos(geo, node, key); + fill = getfill(geo, node, pos); + if ((level == 1) && (keycmp(geo, node, pos, key) != 0)) + return NULL; + ret = bval(geo, node, pos); + + /* remove and shift */ + for (i = pos; i < fill - 1; i++) { + setkey(geo, node, i, bkey(geo, node, i + 1)); + setval(geo, node, i, bval(geo, node, i + 1)); + } + clearpair(geo, node, fill - 1); + + if (fill - 1 < geo->no_pairs / 2) { + if (level < head->height) + rebalance(head, geo, key, level, node, fill - 1); + else if (fill - 1 == 1) + btree_shrink(head, geo); + } + + return ret; +} + +void *btree_remove(struct btree_head *head, struct btree_geo *geo, + unsigned long *key) +{ + if (head->height == 0) + return NULL; + + return btree_remove_level(head, geo, key, 1); +} +EXPORT_SYMBOL_GPL(btree_remove); + +int btree_merge(struct btree_head *target, struct btree_head *victim, + struct btree_geo *geo, gfp_t gfp) +{ + unsigned long key[geo->keylen]; + unsigned long dup[geo->keylen]; + void *val; + int err; + + BUG_ON(target == victim); + + if (!(target->node)) { + /* target is empty, just copy fields over */ + target->node = victim->node; + target->height = victim->height; + __btree_init(victim); + return 0; + } + + /* TODO: This needs some optimizations. Currently we do three tree + * walks to remove a single object from the victim. + */ + for (;;) { + if (!btree_last(victim, geo, key)) + break; + val = btree_lookup(victim, geo, key); + err = btree_insert(target, geo, key, val, gfp); + if (err) + return err; + /* We must make a copy of the key, as the original will get + * mangled inside btree_remove. */ + longcpy(dup, key, geo->keylen); + btree_remove(victim, geo, dup); + } + return 0; +} +EXPORT_SYMBOL_GPL(btree_merge); + +static size_t __btree_for_each(struct btree_head *head, struct btree_geo *geo, + unsigned long *node, unsigned long opaque, + void (*func)(void *elem, unsigned long opaque, + unsigned long *key, size_t index, + void *func2), + void *func2, int reap, int height, size_t count) +{ + int i; + unsigned long *child; + + for (i = 0; i < geo->no_pairs; i++) { + child = bval(geo, node, i); + if (!child) + break; + if (height > 1) + count = __btree_for_each(head, geo, child, opaque, + func, func2, reap, height - 1, count); + else + func(child, opaque, bkey(geo, node, i), count++, + func2); + } + if (reap) + mempool_free(node, head->mempool); + return count; +} + +static void empty(void *elem, unsigned long opaque, unsigned long *key, + size_t index, void *func2) +{ +} + +void visitorl(void *elem, unsigned long opaque, unsigned long *key, + size_t index, void *__func) +{ + visitorl_t func = __func; + + func(elem, opaque, *key, index); +} +EXPORT_SYMBOL_GPL(visitorl); + +void visitor32(void *elem, unsigned long opaque, unsigned long *__key, + size_t index, void *__func) +{ + visitor32_t func = __func; + u32 *key = (void *)__key; + + func(elem, opaque, *key, index); +} +EXPORT_SYMBOL_GPL(visitor32); + +void visitor64(void *elem, unsigned long opaque, unsigned long *__key, + size_t index, void *__func) +{ + visitor64_t func = __func; + u64 *key = (void *)__key; + + func(elem, opaque, *key, index); +} +EXPORT_SYMBOL_GPL(visitor64); + +void visitor128(void *elem, unsigned long opaque, unsigned long *__key, + size_t index, void *__func) +{ + visitor128_t func = __func; + u64 *key = (void *)__key; + + func(elem, opaque, key[0], key[1], index); +} +EXPORT_SYMBOL_GPL(visitor128); + +size_t btree_visitor(struct btree_head *head, struct btree_geo *geo, + unsigned long opaque, + void (*func)(void *elem, unsigned long opaque, + unsigned long *key, + size_t index, void *func2), + void *func2) +{ + size_t count = 0; + + if (!func2) + func = empty; + if (head->node) + count = __btree_for_each(head, geo, head->node, opaque, func, + func2, 0, head->height, 0); + return count; +} +EXPORT_SYMBOL_GPL(btree_visitor); + +size_t btree_grim_visitor(struct btree_head *head, struct btree_geo *geo, + unsigned long opaque, + void (*func)(void *elem, unsigned long opaque, + unsigned long *key, + size_t index, void *func2), + void *func2) +{ + size_t count = 0; + + if (!func2) + func = empty; + if (head->node) + count = __btree_for_each(head, geo, head->node, opaque, func, + func2, 1, head->height, 0); + __btree_init(head); + return count; +} +EXPORT_SYMBOL_GPL(btree_grim_visitor); + +static int __init btree_module_init(void) +{ + btree_cachep = kmem_cache_create("btree_node", NODESIZE, 0, + SLAB_HWCACHE_ALIGN, NULL); + return 0; +} + +static void __exit btree_module_exit(void) +{ + kmem_cache_destroy(btree_cachep); +} + +/* If core code starts using btree, initialization should happen even earlier */ +module_init(btree_module_init); +module_exit(btree_module_exit); + +MODULE_AUTHOR("Joern Engel <joern@logfs.org>"); +MODULE_AUTHOR("Johannes Berg <johannes@sipsolutions.net>"); +MODULE_LICENSE("GPL"); |