This is a note to let you know that I've just added the patch titled
btrfs: error when COWing block from a root that is being deleted
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
btrfs-error-when-cowing-block-from-a-root-that-is-be.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit bb042487f4f980d28a5ce2fa71bdb3183545bf2c
Author: Filipe Manana <fdmanana@xxxxxxxx>
Date: Wed Sep 27 12:09:22 2023 +0100
btrfs: error when COWing block from a root that is being deleted
[ 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>
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 8bc1166215138..8fe6aaa7b11fd 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -545,9 +545,13 @@ 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
