Commit d1c6e680 authored Jul 21, 2023 by Filipe Manana Committed by Greg Kroah-Hartman Aug 11, 2023

btrfs: check for commit error at btrfs_attach_transaction_barrier()



commit b28ff3a7d7e97456fd86b68d24caa32e1cfa7064 upstream.

btrfs_attach_transaction_barrier() is used to get a handle pointing to the
current running transaction if the transaction has not started its commit
yet (its state is < TRANS_STATE_COMMIT_START). If the transaction commit
has started, then we wait for the transaction to commit and finish before
returning - however we completely ignore if the transaction was aborted
due to some error during its commit, we simply return ERR_PT(-ENOENT),
which makes the caller assume everything is fine and no errors happened.

This could make an fsync return success (0) to user space when in fact we
had a transaction abort and the target inode changes were therefore not
persisted.

Fix this by checking for the return value from btrfs_wait_for_commit(),
and if it returned an error, return it back to the caller.

Fixes: d4edf39b ("Btrfs: fix uncompleted transaction")
CC: stable@vger.kernel.org # 4.19+
Reviewed-by: Qu Wenruo <wqu@suse.com>
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent ee2eed83

fs/btrfs/transaction.c

+7 −2

Original line number	Diff line number	Diff line
		@@ -706,8 +706,13 @@ btrfs_attach_transaction_barrier(struct btrfs_root *root)

		trans = start_transaction(root, 0, TRANS_ATTACH,
		BTRFS_RESERVE_NO_FLUSH, true);
		if (trans == ERR_PTR(-ENOENT))
		btrfs_wait_for_commit(root->fs_info, 0);
		if (trans == ERR_PTR(-ENOENT)) {
		int ret;

		ret = btrfs_wait_for_commit(root->fs_info, 0);
		if (ret)
		return ERR_PTR(ret);
		}

		return trans;
		}