6.1-stable review patch. If anyone has any objections, please let me know.
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From: Filipe Manana fdmanana@suse.com
[ 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@suse.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/ctree.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 98e3e0761a4e5..98f68bd1383a3 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -563,9 +563,13 @@ 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