From: Josef Bacik <josef@toxicpanda.com> stable inclusion from stable-v5.10.112 commit 76e086ce7b2d71b0d7a1a121c5f53b5fa07c1c8c category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5HL0X Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit a7d16d9a07bbcb7dcd5214a1bea75c808830bc0d ] This is a long time leftover from when I originally added the free space inode, the point was to catch cases where we weren't honoring the NOCOW flag. However there exists a race with relocation, if we allocate our free space inode in a block group that is about to be relocated, we could trigger the COW path before the relocation has the opportunity to find the extents and delete the free space cache. In production where we have auto-relocation enabled we're seeing this WARN_ON_ONCE() around 5k times in a 2 week period, so not super common but enough that it's at the top of our metrics. We're properly handling the error here, and with us phasing out v1 space cache anyway just drop the WARN_ON_ONCE. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> Acked-by: Xie XiuQi <xiexiuqi@huawei.com> --- fs/btrfs/inode.c | 1 - 1 file changed, 1 deletion(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index f7f4ac01589b..4a5248097d7a 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -995,7 +995,6 @@ static noinline int cow_file_range(struct btrfs_inode *inode, int ret = 0; if (btrfs_is_free_space_inode(inode)) { - WARN_ON_ONCE(1); ret = -EINVAL; goto out_unlock; } -- 2.20.1