From: Josef Bacik josef@toxicpanda.com
commit 9076dbd5ee837c3882fc42891c14cecd0354a849 upstream.
While fixing up our ->last_byte_to_unpin locking I noticed that we will shorten len based on ->last_byte_to_unpin if we're caching when we're adding back the free space. This is correct for the free space, as we cannot unpin more than ->last_byte_to_unpin, however we use len to adjust the ->bytes_pinned counters and such, which need to track the actual pinned usage. This could result in WARN_ON(space_info->bytes_pinned) triggering at unmount time.
Fix this by using a local variable for the amount to add to free space cache, and leave len untouched in this case.
CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Filipe Manana fdmanana@suse.com Signed-off-by: Josef Bacik josef@toxicpanda.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/btrfs/extent-tree.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
--- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -2838,10 +2838,10 @@ static int unpin_extent_range(struct btr len = cache->key.objectid + cache->key.offset - start; len = min(len, end + 1 - start);
- if (start < cache->last_byte_to_unpin) { - len = min(len, cache->last_byte_to_unpin - start); - if (return_free_space) - btrfs_add_free_space(cache, start, len); + if (start < cache->last_byte_to_unpin && return_free_space) { + u64 add_len = min(len, cache->last_byte_to_unpin - start); + + btrfs_add_free_space(cache, start, add_len); }
start += len;