From a2caab29884397e583d09be6546259a83ebfbdb1 Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Wed, 27 Sep 2023 12:09:22 +0100 Subject: btrfs: error when COWing block from a root that is being deleted 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 Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/ctree.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'fs/btrfs') diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 7afd0a6495f3..db1f3bc7f328 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 -- cgit v1.2.3