diff options
| -rw-r--r-- | fs/btrfs/extent-tree.c | 85 |
1 files changed, 79 insertions, 6 deletions
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 3b26f0980946..7a22f2e6ec47 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -19,6 +19,7 @@ #include <linux/pagemap.h> #include <linux/writeback.h> #include <linux/blkdev.h> +#include <linux/sort.h> #include "compat.h" #include "hash.h" #include "crc32c.h" @@ -1521,15 +1522,50 @@ out: return ret; } -int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, - struct extent_buffer *orig_buf, struct extent_buffer *buf, - u32 *nr_extents) +/* when a block goes through cow, we update the reference counts of + * everything that block points to. The internal pointers of the block + * can be in just about any order, and it is likely to have clusters of + * things that are close together and clusters of things that are not. + * + * To help reduce the seeks that come with updating all of these reference + * counts, sort them by byte number before actual updates are done. + * + * struct refsort is used to match byte number to slot in the btree block. + * we sort based on the byte number and then use the slot to actually + * find the item. + */ +struct refsort { + u64 bytenr; + u32 slot; +}; + +/* + * for passing into sort() + */ +static int refsort_cmp(const void *a_void, const void *b_void) +{ + const struct refsort *a = a_void; + const struct refsort *b = b_void; + + if (a->bytenr < b->bytenr) + return -1; + if (a->bytenr > b->bytenr) + return 1; + return 0; +} + + +noinline int btrfs_inc_ref(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct extent_buffer *orig_buf, + struct extent_buffer *buf, u32 *nr_extents) { u64 bytenr; u64 ref_root; u64 orig_root; u64 ref_generation; u64 orig_generation; + struct refsort *sorted; u32 nritems; u32 nr_file_extents = 0; struct btrfs_key key; @@ -1538,6 +1574,8 @@ int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, int level; int ret = 0; int faili = 0; + int refi = 0; + int slot; int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *, u64, u64, u64, u64, u64, u64, u64, u64); @@ -1549,6 +1587,9 @@ int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, nritems = btrfs_header_nritems(buf); level = btrfs_header_level(buf); + sorted = kmalloc(sizeof(struct refsort) * nritems, GFP_NOFS); + BUG_ON(!sorted); + if (root->ref_cows) { process_func = __btrfs_inc_extent_ref; } else { @@ -1561,6 +1602,11 @@ int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, process_func = __btrfs_update_extent_ref; } + /* + * we make two passes through the items. In the first pass we + * only record the byte number and slot. Then we sort based on + * byte number and do the actual work based on the sorted results + */ for (i = 0; i < nritems; i++) { cond_resched(); if (level == 0) { @@ -1577,6 +1623,32 @@ int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, continue; nr_file_extents++; + sorted[refi].bytenr = bytenr; + sorted[refi].slot = i; + refi++; + } else { + bytenr = btrfs_node_blockptr(buf, i); + sorted[refi].bytenr = bytenr; + sorted[refi].slot = i; + refi++; + } + } + /* + * if refi == 0, we didn't actually put anything into the sorted + * array and we're done + */ + if (refi == 0) + goto out; + + sort(sorted, refi, sizeof(struct refsort), refsort_cmp, NULL); + + for (i = 0; i < refi; i++) { + cond_resched(); + slot = sorted[i].slot; + bytenr = sorted[i].bytenr; + + if (level == 0) { + btrfs_item_key_to_cpu(buf, &key, slot); ret = process_func(trans, root, bytenr, orig_buf->start, buf->start, @@ -1585,25 +1657,25 @@ int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root, key.objectid); if (ret) { - faili = i; + faili = slot; WARN_ON(1); goto fail; } } else { - bytenr = btrfs_node_blockptr(buf, i); ret = process_func(trans, root, bytenr, orig_buf->start, buf->start, orig_root, ref_root, orig_generation, ref_generation, level - 1); if (ret) { - faili = i; + faili = slot; WARN_ON(1); goto fail; } } } out: + kfree(sorted); if (nr_extents) { if (level == 0) *nr_extents = nr_file_extents; @@ -1612,6 +1684,7 @@ out: } return 0; fail: + kfree(sorted); WARN_ON(1); return ret; } |