diff options
Diffstat (limited to 'free-space-cache.c')
| -rw-r--r-- | free-space-cache.c | 35 |
1 files changed, 25 insertions, 10 deletions
diff --git a/free-space-cache.c b/free-space-cache.c index 50356d04..9b83a71c 100644 --- a/free-space-cache.c +++ b/free-space-cache.c @@ -54,8 +54,7 @@ static int io_ctl_init(struct io_ctl *io_ctl, u64 size, u64 ino, struct btrfs_root *root) { memset(io_ctl, 0, sizeof(struct io_ctl)); - io_ctl->num_pages = (size + root->fs_info->sectorsize - 1) / - root->fs_info->sectorsize; + io_ctl->num_pages = DIV_ROUND_UP(size, root->fs_info->sectorsize); io_ctl->buffer = kzalloc(size, GFP_NOFS); if (!io_ctl->buffer) return -ENOMEM; @@ -439,7 +438,8 @@ int load_free_space_cache(struct btrfs_fs_info *fs_info, struct btrfs_path *path; u64 used = btrfs_block_group_used(&block_group->item); int ret = 0; - int matched; + u64 bg_free; + s64 diff; path = btrfs_alloc_path(); if (!path) @@ -449,18 +449,33 @@ int load_free_space_cache(struct btrfs_fs_info *fs_info, block_group->key.objectid); btrfs_free_path(path); - matched = (ctl->free_space == (block_group->key.offset - used - - block_group->bytes_super)); - if (ret == 1 && !matched) { - __btrfs_remove_free_space_cache(ctl); + bg_free = block_group->key.offset - used - block_group->bytes_super; + diff = ctl->free_space - bg_free; + if (ret == 1 && diff) { fprintf(stderr, - "block group %llu has wrong amount of free space\n", - block_group->key.objectid); + "block group %llu has wrong amount of free space, free space cache has %llu block group has %llu\n", + block_group->key.objectid, ctl->free_space, bg_free); + __btrfs_remove_free_space_cache(ctl); + /* + * Due to btrfs_reserve_extent() can happen out of a + * transaction, but all btrfs_release_extent() happens inside + * a transaction, so under heavy race it's possible that free + * space cache has less free space, and both kernel just discard + * such cache. But if we find some case where free space cache + * has more free space, this means under certain case such + * cache can be loaded and cause double allocate. + * + * Detect such possibility here. + */ + if (diff > 0) + error( +"free space cache has more free space than block group item, this could leads to serious corruption, please contact btrfs developers"); ret = -1; } if (ret < 0) { - ret = 0; + if (diff <= 0) + ret = 0; fprintf(stderr, "failed to load free space cache for block group %llu\n", |