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authorFilipe Manana <fdmanana@suse.com>2023-05-04 12:04:18 +0100
committerDavid Sterba <dsterba@suse.com>2023-05-09 22:08:05 +0200
commit0004ff15ea26015a0a3a6182dca3b9d1df32e2b7 (patch)
tree136138327cb71645b4dfd2828e2585b01b66f98b
parentc87f318e6f47696b4040b58f460d5c17ea0280e6 (diff)
btrfs: fix space cache inconsistency after error loading it from disk
When loading a free space cache from disk, at __load_free_space_cache(), if we fail to insert a bitmap entry, we still increment the number of total bitmaps in the btrfs_free_space_ctl structure, which is incorrect since we failed to add the bitmap entry. On error we then empty the cache by calling __btrfs_remove_free_space_cache(), which will result in getting the total bitmaps counter set to 1. A failure to load a free space cache is not critical, so if a failure happens we just rebuild the cache by scanning the extent tree, which happens at block-group.c:caching_thread(). Yet the failure will result in having the total bitmaps of the btrfs_free_space_ctl always bigger by 1 then the number of bitmap entries we have. So fix this by having the total bitmaps counter be incremented only if we successfully added the bitmap entry. Fixes: a67509c30079 ("Btrfs: add a io_ctl struct and helpers for dealing with the space cache") Reviewed-by: Anand Jain <anand.jain@oracle.com> CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
-rw-r--r--fs/btrfs/free-space-cache.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index d84cef89cdff..cf98a3c05480 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -870,15 +870,16 @@ static int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
}
spin_lock(&ctl->tree_lock);
ret = link_free_space(ctl, e);
- ctl->total_bitmaps++;
- recalculate_thresholds(ctl);
- spin_unlock(&ctl->tree_lock);
if (ret) {
+ spin_unlock(&ctl->tree_lock);
btrfs_err(fs_info,
"Duplicate entries in free space cache, dumping");
kmem_cache_free(btrfs_free_space_cachep, e);
goto free_cache;
}
+ ctl->total_bitmaps++;
+ recalculate_thresholds(ctl);
+ spin_unlock(&ctl->tree_lock);
list_add_tail(&e->list, &bitmaps);
}