Re: [PATCH] md: limit mdstat resync progress to max_sectors

[Nate Dailey <nate.dailey@stratus.com>]

Yes, I also wondered if setting curr_resync to MaxSector could be changed... but 
not understanding why it's done, it seemed safer to just catch this in 
status_resync.

Nate



On 12/01/2017 03:37 AM, Guoqing Jiang wrote:
> Actually, it is recovery :).
>
>
> On 12/01/2017 12:33 AM, Nate Dailey wrote:
> > There is a small window near the end of md_do_sync where mddev->curr_resync
> > can be equal to MaxSector.
>
> I am curious about the purpose of set it to MaxSector, maybe the setting
> is not
> necessary.
>
> Acked-by: Guoqing Jiang <gqjiang@suse.com>
>
> Thanks,
> Guoqing
>
> > If status_resync is called during this window, the resulting /proc/mdstat
> > output contains a HUGE number of = signs due to the very large curr_resync:
> >
> > Personalities : [raid1]
> > md123 : active raid1 sdd3[2] sdb3[0]
> > 204736 blocks super 1.0 [2/1] [U_]
> > [=====================================================================
> > ... (82 MB more) ...
> > ================>] recovery =429496729.3% (9223372036854775807/204736)
> > finish=0.2min speed=12796K/sec
> > bitmap: 0/1 pages [0KB], 65536KB chunk
> >
> > Modify status_resync to ensure the resync variable doesn't exceed
> > the array's max_sectors.
> >
> > Signed-off-by: Nate Dailey <nate.dailey@stratus.com>
> > ---
> > drivers/md/md.c | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/md/md.c b/drivers/md/md.c
> > index 41c050b59ec4..4e4dee0ec2de 100644
> > --- a/drivers/md/md.c
> > +++ b/drivers/md/md.c
> > @@ -7605,7 +7605,9 @@ static int status_resync(struct seq_file *seq, struct 
> mddev *mddev)
> > if (test_bit(MD_RECOVERY_DONE, &mddev->recovery))
> > /* Still cleaning up */
> > resync = max_sectors;
> > - } else
> > + } else if (resync > max_sectors)
> > + resync = max_sectors;
> > + else
> > resync -= atomic_read(&mddev->recovery_active);
> >
> > if (resync == 0) {
>
> --
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