6.5-stable review patch. If anyone has any objections, please let me know.
------------------
From: Filipe Manana <fdmanana@xxxxxxxx>
[ Upstream commit a2caab29884397e583d09be6546259a83ebfbdb1 ]
At btrfs_cow_block() we check if the block being COWed belongs to a root
that is being deleted and if so we log an error message. However this is
an unexpected case and it indicates a bug somewhere, so we should return
an error and abort the transaction. So change this in the following ways:
1) Abort the transaction with -EUCLEAN, so that if the issue ever happens
it can easily be noticed;
2) Change the logged message level from error to critical, and change the
message itself to print the block's logical address and the ID of the
root;
3) Return -EUCLEAN to the caller;
4) As this is an unexpected scenario, that should never happen, mark the
check as unlikely, allowing the compiler to potentially generate better
code.
Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
fs/btrfs/ctree.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 7afd0a6495f37..db1f3bc7f3284 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -682,9 +682,13 @@ noinline int btrfs_cow_block(struct btrfs_trans_handle *trans,
u64 search_start;
int ret;
- if (test_bit(BTRFS_ROOT_DELETING, &root->state))
- btrfs_err(fs_info,
- "COW'ing blocks on a fs root that's being dropped");
+ if (unlikely(test_bit(BTRFS_ROOT_DELETING, &root->state))) {
+ btrfs_abort_transaction(trans, -EUCLEAN);
+ btrfs_crit(fs_info,
+ "attempt to COW block %llu on root %llu that is being deleted",
+ buf->start, btrfs_root_id(root));
+ return -EUCLEAN;
+ }
/*
* COWing must happen through a running transaction, which always
--
2.40.1
