On Fri, Feb 14, 2020 at 01:15:28PM -0500, Brian Foster wrote:
> Prior to commit df732b29c8 ("xfs: call xlog_state_release_iclog with
> l_icloglock held"), xlog_state_release_iclog() always performed a
> locked check of the iclog error state before proceeding into the
> sync state processing code. As of this commit, part of
> xlog_state_release_iclog() was open-coded into
> xfs_log_release_iclog() and as a result the locked error state check
> was lost.
>
> The lockless check still exists, but this doesn't account for the
> possibility of a race with a shutdown being performed by another
> task causing the iclog state to change while the original task waits
> on ->l_icloglock. This has reproduced very rarely via generic/475
> and manifests as an assert failure in __xlog_state_release_iclog()
> due to an unexpected iclog state.
>
> Restore the locked error state check in xlog_state_release_iclog()
> to ensure that an iclog state update via shutdown doesn't race with
> the iclog release state processing code.
>
> Reported-by: Zorro Lang <zlang@xxxxxxxxxx>
> Signed-off-by: Brian Foster <bfoster@xxxxxxxxxx>
> ---
> fs/xfs/xfs_log.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
> index f6006d94a581..f38fc492a14d 100644
> --- a/fs/xfs/xfs_log.c
> +++ b/fs/xfs/xfs_log.c
> @@ -611,6 +611,10 @@ xfs_log_release_iclog(
> }
>
> if (atomic_dec_and_lock(&iclog->ic_refcnt, &log->l_icloglock)) {
> + if (iclog->ic_state == XLOG_STATE_IOERROR) {
> + spin_unlock(&log->l_icloglock);
> + return -EIO;
> + }
So the check just above also shuts the file system down. Any reason to
do that in one case and not the other?
