diff options
| -rw-r--r-- | fs/nilfs2/super.c | 80 | ||||
| -rw-r--r-- | fs/nilfs2/the_nilfs.c | 57 | ||||
| -rw-r--r-- | fs/nilfs2/the_nilfs.h | 4 |
3 files changed, 76 insertions, 65 deletions
diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c index 1c505d0e031..3c9833e3e74 100644 --- a/fs/nilfs2/super.c +++ b/fs/nilfs2/super.c @@ -1061,13 +1061,6 @@ static int nilfs_set_bdev_super(struct super_block *s, void *data) static int nilfs_test_bdev_super(struct super_block *s, void *data) { struct nilfs_super_data *sd = data; - - return s->s_bdev == sd->bdev; -} - -static int nilfs_test_bdev_super2(struct super_block *s, void *data) -{ - struct nilfs_super_data *sd = data; int ret; if (s->s_bdev != sd->bdev) @@ -1096,8 +1089,8 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags, const char *dev_name, void *data, struct vfsmount *mnt) { struct nilfs_super_data sd; - struct super_block *s, *s2; - struct the_nilfs *nilfs = NULL; + struct super_block *s; + struct the_nilfs *nilfs; int err, need_to_close = 1; sd.bdev = open_bdev_exclusive(dev_name, flags, fs_type); @@ -1118,11 +1111,12 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags, goto failed; } - /* - * once the super is inserted into the list by sget, s_umount - * will protect the lockfs code from trying to start a snapshot - * while we are mounting - */ + nilfs = find_or_create_nilfs(sd.bdev); + if (!nilfs) { + err = -ENOMEM; + goto failed; + } + down(&sd.bdev->bd_mount_sem); if (!sd.cno && (err = test_exclusive_mount(fs_type, sd.bdev, flags ^ MS_RDONLY))) { @@ -1131,51 +1125,22 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags, } /* - * Phase-1: search any existent instance and get the_nilfs + * Search specified snapshot or R/W mode super_block */ - s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, &sd); - if (IS_ERR(s)) - goto error_s; - - if (!s->s_root) { - err = -ENOMEM; - nilfs = alloc_nilfs(sd.bdev); - if (!nilfs) - goto cancel_new; - } else { - struct nilfs_sb_info *sbi = NILFS_SB(s); + if (!sd.cno) + /* trying to get the latest checkpoint. */ + sd.cno = nilfs_last_cno(nilfs); - /* - * s_umount protects super_block from unmount process; - * It covers pointers of nilfs_sb_info and the_nilfs. - */ - nilfs = sbi->s_nilfs; - get_nilfs(nilfs); - up_write(&s->s_umount); - - /* - * Phase-2: search specified snapshot or R/W mode super_block - */ - if (!sd.cno) - /* trying to get the latest checkpoint. */ - sd.cno = nilfs_last_cno(nilfs); - - s2 = sget(fs_type, nilfs_test_bdev_super2, - nilfs_set_bdev_super, &sd); - deactivate_super(s); - /* - * Although deactivate_super() invokes close_bdev_exclusive() at - * kill_block_super(). Here, s is an existent mount; we need - * one more close_bdev_exclusive() call. - */ - s = s2; - if (IS_ERR(s)) - goto error_s; + s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, &sd); + if (IS_ERR(s)) { + err = PTR_ERR(s); + goto failed_unlock; } if (!s->s_root) { char b[BDEVNAME_SIZE]; + /* New superblock instance created */ s->s_flags = flags; strlcpy(s->s_id, bdevname(sd.bdev, b), sizeof(s->s_id)); sb_set_blocksize(s, block_size(sd.bdev)); @@ -1195,15 +1160,9 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags, simple_set_mnt(mnt, s); return 0; - error_s: - up(&sd.bdev->bd_mount_sem); - if (nilfs) - put_nilfs(nilfs); - close_bdev_exclusive(sd.bdev, flags); - return PTR_ERR(s); - failed_unlock: up(&sd.bdev->bd_mount_sem); + put_nilfs(nilfs); failed: close_bdev_exclusive(sd.bdev, flags); @@ -1212,8 +1171,7 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags, cancel_new: /* Abandoning the newly allocated superblock */ up(&sd.bdev->bd_mount_sem); - if (nilfs) - put_nilfs(nilfs); + put_nilfs(nilfs); up_write(&s->s_umount); deactivate_super(s); /* diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c index a91f15b8673..45dbf6a6174 100644 --- a/fs/nilfs2/the_nilfs.c +++ b/fs/nilfs2/the_nilfs.c @@ -35,6 +35,10 @@ #include "seglist.h" #include "segbuf.h" + +static LIST_HEAD(nilfs_objects); +static DEFINE_SPINLOCK(nilfs_lock); + void nilfs_set_last_segment(struct the_nilfs *nilfs, sector_t start_blocknr, u64 seq, __u64 cno) { @@ -55,7 +59,7 @@ void nilfs_set_last_segment(struct the_nilfs *nilfs, * Return Value: On success, pointer to the_nilfs is returned. * On error, NULL is returned. */ -struct the_nilfs *alloc_nilfs(struct block_device *bdev) +static struct the_nilfs *alloc_nilfs(struct block_device *bdev) { struct the_nilfs *nilfs; @@ -69,6 +73,7 @@ struct the_nilfs *alloc_nilfs(struct block_device *bdev) atomic_set(&nilfs->ns_ndirtyblks, 0); init_rwsem(&nilfs->ns_sem); mutex_init(&nilfs->ns_writer_mutex); + INIT_LIST_HEAD(&nilfs->ns_list); INIT_LIST_HEAD(&nilfs->ns_supers); spin_lock_init(&nilfs->ns_last_segment_lock); nilfs->ns_gc_inodes_h = NULL; @@ -78,6 +83,45 @@ struct the_nilfs *alloc_nilfs(struct block_device *bdev) } /** + * find_or_create_nilfs - find or create nilfs object + * @bdev: block device to which the_nilfs is related + * + * find_nilfs() looks up an existent nilfs object created on the + * device and gets the reference count of the object. If no nilfs object + * is found on the device, a new nilfs object is allocated. + * + * Return Value: On success, pointer to the nilfs object is returned. + * On error, NULL is returned. + */ +struct the_nilfs *find_or_create_nilfs(struct block_device *bdev) +{ + struct the_nilfs *nilfs, *new = NULL; + + retry: + spin_lock(&nilfs_lock); + list_for_each_entry(nilfs, &nilfs_objects, ns_list) { + if (nilfs->ns_bdev == bdev) { + get_nilfs(nilfs); + spin_unlock(&nilfs_lock); + if (new) + put_nilfs(new); + return nilfs; /* existing object */ + } + } + if (new) { + list_add_tail(&new->ns_list, &nilfs_objects); + spin_unlock(&nilfs_lock); + return new; /* new object */ + } + spin_unlock(&nilfs_lock); + + new = alloc_nilfs(bdev); + if (new) + goto retry; + return NULL; /* insufficient memory */ +} + +/** * put_nilfs - release a reference to the_nilfs * @nilfs: the_nilfs structure to be released * @@ -86,13 +130,20 @@ struct the_nilfs *alloc_nilfs(struct block_device *bdev) */ void put_nilfs(struct the_nilfs *nilfs) { - if (!atomic_dec_and_test(&nilfs->ns_count)) + spin_lock(&nilfs_lock); + if (!atomic_dec_and_test(&nilfs->ns_count)) { + spin_unlock(&nilfs_lock); return; + } + list_del_init(&nilfs->ns_list); + spin_unlock(&nilfs_lock); + /* - * Increment of ns_count never occur below because the caller + * Increment of ns_count never occurs below because the caller * of get_nilfs() holds at least one reference to the_nilfs. * Thus its exclusion control is not required here. */ + might_sleep(); if (nilfs_loaded(nilfs)) { nilfs_mdt_clear(nilfs->ns_sufile); diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h index 30fe58778d0..116caf96e7f 100644 --- a/fs/nilfs2/the_nilfs.h +++ b/fs/nilfs2/the_nilfs.h @@ -43,6 +43,7 @@ enum { * struct the_nilfs - struct to supervise multiple nilfs mount points * @ns_flags: flags * @ns_count: reference count + * @ns_list: list head for nilfs_list * @ns_bdev: block device * @ns_bdi: backing dev info * @ns_writer: back pointer to writable nilfs_sb_info @@ -88,6 +89,7 @@ enum { struct the_nilfs { unsigned long ns_flags; atomic_t ns_count; + struct list_head ns_list; struct block_device *ns_bdev; struct backing_dev_info *ns_bdi; @@ -191,7 +193,7 @@ THE_NILFS_FNS(DISCONTINUED, discontinued) #define NILFS_ALTSB_FREQ 60 /* spare superblock */ void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64); -struct the_nilfs *alloc_nilfs(struct block_device *); +struct the_nilfs *find_or_create_nilfs(struct block_device *); void put_nilfs(struct the_nilfs *); int init_nilfs(struct the_nilfs *, struct nilfs_sb_info *, char *); int load_nilfs(struct the_nilfs *, struct nilfs_sb_info *); |