[PATCH 4.19 073/421] btrfs: fix error handling in __btrfs_update_delayed_inode

Greg Kroah-Hartman
2021-07-19T16:09:35Z

From: Josef Bacik <josef@toxicpanda.com>

[ Upstream commit bb385bedded3ccbd794559600de4a09448810f4a ]

If we get an error while looking up the inode item we'll simply bail
without cleaning up the delayed node. This results in this style of
warning happening on commit:

WARNING: CPU: 0 PID: 76403 at fs/btrfs/delayed-inode.c:1365 btrfs_assert_delayed_root_empty+0x5b/0x90
CPU: 0 PID: 76403 Comm: fsstress Tainted: G W 5.13.0-rc1+ #373
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014
RIP: 0010:btrfs_assert_delayed_root_empty+0x5b/0x90
RSP: 0018:ffffb8bb815a7e50 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffff95d6d07e1888 RCX: ffff95d6c0fa3000
RDX: 0000000000000002 RSI: 000000000029e91c RDI: ffff95d6c0fc8060
RBP: ffff95d6c0fc8060 R08: 00008d6d701a2c1d R09: 0000000000000000
R10: ffff95d6d1760ea0 R11: 0000000000000001 R12: ffff95d6c15a4d00
R13: ffff95d6c0fa3000 R14: 0000000000000000 R15: ffffb8bb815a7e90
FS: 00007f490e8dbb80(0000) GS:ffff95d73bc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6e75555cb0 CR3: 00000001101ce001 CR4: 0000000000370ef0
Call Trace:
btrfs_commit_transaction+0x43c/0xb00
? finish_wait+0x80/0x80
? vfs_fsync_range+0x90/0x90
iterate_supers+0x8c/0x100
ksys_sync+0x50/0x90
__do_sys_sync+0xa/0x10
do_syscall_64+0x3d/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xae

Because the iref isn't dropped and this leaves an elevated node->count,
so any release just re-queues it onto the delayed inodes list. Fix this
by going to the out label to handle the proper cleanup of the delayed
node.

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>
---
fs/btrfs/delayed-inode.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
index fea5ccfade5c..f3994ee1a6e6 100644
--- a/fs/btrfs/delayed-inode.c
+++ b/fs/btrfs/delayed-inode.c
@@ -1030,12 +1030,10 @@ static int __btrfs_update_delayed_inode(struct btrfs_trans_handle *trans,
nofs_flag = memalloc_nofs_save();
ret = btrfs_lookup_inode(trans, root, path, &key, mod);
memalloc_nofs_restore(nofs_flag);
- if (ret > 0) {
- btrfs_release_path(path);
- return -ENOENT;
- } else if (ret < 0) {
- return ret;
- }
+ if (ret > 0)
+ ret = -ENOENT;
+ if (ret < 0)
+ goto out;

leaf = path->nodes[0];
inode_item = btrfs_item_ptr(leaf, path->slots[0],
--
2.30.2