On Tue, 12 Mar 2013 14:45:44 +0100 Jes Sorensen <Jes.Sorensen@xxxxxxxxxx>
wrote:
> NeilBrown <neilb@xxxxxxx> writes:
> > On Tue, 12 Mar 2013 09:32:31 +1100 NeilBrown <neilb@xxxxxxx> wrote:
> >
> >> On Wed, 06 Mar 2013 10:31:55 +0100 Jes Sorensen <Jes.Sorensen@xxxxxxxxxx>
> >> wrote:
> >>
> >
> >> >
> >> > I am attaching the test script I am running too. It was written by Eryu
> >> > Guan.
> >>
> >> Thanks for that. I've tried using it but haven't managed to trigger a BUG
> >> yet. What size are the loop files? I mostly use fairly small ones, but
> >> maybe it needs to be bigger to trigger the problem.
> >
> > Shortly after I wrote that I got a bug-on! It hasn't happened again though.
> >
> > This was using code without that latest patch I sent. The bug was
> > BUG_ON(s->uptodate != disks);
> >
> > in the check_state_compute_result case of handle_parity_checks5() which is
> > probably the same cause as your most recent BUG.
> >
> > I've revised my thinking a bit and am now running with this patch which I
> > think should fix a problem that probably caused the symptoms we have seen.
> >
> > If you could run your tests for a while too and is whether it will still crash
> > for you, I'd really appreciate it.
>
> Hi Neil,
>
> Sorry I can't verify the line numbers of my old test since I managed to
> mess up my git tree in the process :(
>
> However running with this new patch I have just hit another but
> different case. Looks like a deadlock.
You test setup is clearly different from mine. I've been running all night
without a single hiccup.
>
> This is basically running ca64cae96037de16e4af92678814f5d4bf0c1c65 with
> your patch applied on top, and nothing else.
>
> If you want me to try a more uptodate Linus tree, please let me know.
>
> Cheers,
> Jes
>
>
> [17635.205927] INFO: task mkfs.ext4:20060 blocked for more than 120 seconds.
> [17635.213543] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> [17635.222291] mkfs.ext4 D ffff880236814100 0 20060 20026 0x00000080
> [17635.230199] ffff8801bc8bbb98 0000000000000082 ffff88022f0be540 ffff8801bc8bbfd8
> [17635.238518] ffff8801bc8bbfd8 ffff8801bc8bbfd8 ffff88022d47b2a0 ffff88022f0be540
> [17635.246837] ffff8801cea1f430 000000000001d5f0 ffff8801c7f4f430 ffff88022169a400
> [17635.255161] Call Trace:
> [17635.257891] [<ffffffff81614f79>] schedule+0x29/0x70
> [17635.263433] [<ffffffffa0386ada>] make_request+0x6da/0x6f0 [raid456]
> [17635.270525] [<ffffffff81084210>] ? wake_up_bit+0x40/0x40
> [17635.276560] [<ffffffff814a6633>] md_make_request+0xc3/0x200
> [17635.282884] [<ffffffff81134655>] ? mempool_alloc_slab+0x15/0x20
> [17635.289586] [<ffffffff812c70d2>] generic_make_request+0xc2/0x110
> [17635.296393] [<ffffffff812c7199>] submit_bio+0x79/0x160
> [17635.302232] [<ffffffff811ca625>] ? bio_alloc_bioset+0x65/0x120
> [17635.308844] [<ffffffff812ce234>] blkdev_issue_discard+0x184/0x240
> [17635.315748] [<ffffffff812cef76>] blkdev_ioctl+0x3b6/0x810
> [17635.321877] [<ffffffff811cb971>] block_ioctl+0x41/0x50
> [17635.327714] [<ffffffff811a6aa9>] do_vfs_ioctl+0x99/0x580
> [17635.333745] [<ffffffff8128a19a>] ? inode_has_perm.isra.30.constprop.60+0x2a/0x30
> [17635.342103] [<ffffffff8128b6d7>] ? file_has_perm+0x97/0xb0
> [17635.348329] [<ffffffff811a7021>] sys_ioctl+0x91/0xb0
> [17635.353972] [<ffffffff810de9dc>] ? __audit_syscall_exit+0x3ec/0x450
> [17635.361070] [<ffffffff8161e759>] system_call_fastpath+0x16/0x1b
There is a small race in the exclusion between discard and recovery.
This patch on top should fix it (I hope).
Thanks for testing.
NeilBrown
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index c216dd3..636d492 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -4246,14 +4246,14 @@ static void make_discard_request(struct mddev *mddev, struct bio *bi)
sh = get_active_stripe(conf, logical_sector, 0, 0, 0);
prepare_to_wait(&conf->wait_for_overlap, &w,
TASK_UNINTERRUPTIBLE);
- spin_lock_irq(&sh->stripe_lock);
+ set_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
if (test_bit(STRIPE_SYNCING, &sh->state)) {
- set_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
- spin_unlock_irq(&sh->stripe_lock);
release_stripe(sh);
schedule();
goto again;
}
+ clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
+ spin_lock_irq(&sh->stripe_lock);
for (d = 0; d < conf->raid_disks; d++) {
if (d == sh->pd_idx || d == sh->qd_idx)
continue;
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