On Mon, Apr 20, 2020 at 10:02:05AM -0400, Brian Foster wrote:
> On Mon, Apr 20, 2020 at 01:19:59PM +1000, Dave Chinner wrote:
> > On Fri, Apr 17, 2020 at 11:08:52AM -0400, Brian Foster wrote:
> > > At unmount time, XFS emits a warning for every in-core buffer that
> > > might have undergone a write error. In practice this behavior is
> > > probably reasonable given that the filesystem is likely short lived
> > > once I/O errors begin to occur consistently. Under certain test or
> > > otherwise expected error conditions, this can spam the logs and slow
> > > down the unmount. Ratelimit the warning to prevent this problem
> > > while still informing the user that errors have occurred.
> > >
> > > Signed-off-by: Brian Foster <bfoster@xxxxxxxxxx>
> > > ---
> > > fs/xfs/xfs_buf.c | 7 +++----
> > > 1 file changed, 3 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
> > > index 93942d8e35dd..5120fed06075 100644
> > > --- a/fs/xfs/xfs_buf.c
> > > +++ b/fs/xfs/xfs_buf.c
> > > @@ -1685,11 +1685,10 @@ xfs_wait_buftarg(
> > > bp = list_first_entry(&dispose, struct xfs_buf, b_lru);
> > > list_del_init(&bp->b_lru);
> > > if (bp->b_flags & XBF_WRITE_FAIL) {
> > > - xfs_alert(btp->bt_mount,
> > > -"Corruption Alert: Buffer at daddr 0x%llx had permanent write failures!",
> > > + xfs_alert_ratelimited(btp->bt_mount,
> > > +"Corruption Alert: Buffer at daddr 0x%llx had permanent write failures!\n"
> > > +"Please run xfs_repair to determine the extent of the problem.",
> > > (long long)bp->b_bn);
> >
> > Hmmmm. I was under the impression that multiple line log messages
> > were frowned upon because they prevent every output line in the log
> > being tagged correctly. That's where KERN_CONT came from (i.e. it's
> > a continuation of a previous log message), but we don't use that
> > with the XFS logging and hence multi-line log messages are split
> > into multiple logging calls.
> >
>
> I debated combining these into a single line for that exact reason for
> about a second and then just went with this because I didn't think it
> mattered that much.
It doesn't matter to us, but it does matter to those people who want
their log entries correctly tagged for their classification
engines...
> > IOWs, this might be better handled just using a static ratelimit
> > variable here....
> >
> > Actually, we already have one for xfs_buf_item_push() to limit
> > warnings about retrying XBF_WRITE_FAIL buffers:
> >
> > static DEFINE_RATELIMIT_STATE(xfs_buf_write_fail_rl_state, 30 * HZ, 10);
> >
> > Perhaps we should be using the same ratelimit variable here....
> >
>
> IIRC that was static in another file, but we can centralize (and perhaps
> generalize..) it somewhere if that is preferred..
I think it makes sense to have all the buffer write fail
messages ratelimited under the same variable - once it starts
spewing messages, we should limit them all the same way...
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
