From: NeilBrown <neilb@suse.com>
To: Xiao Ni <xni@redhat.com>
Cc: linux-raid@vger.kernel.org
Subject: Re: [PATCH 0/4] RFC: attempt to remove md deadlocks with metadata without
Date: Thu, 05 Oct 2017 16:17:19 +1100 [thread overview]
Message-ID: <87vaju18dc.fsf@notabene.neil.brown.name> (raw)
In-Reply-To: <393232447.10845976.1505375841983.JavaMail.zimbra@redhat.com>
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On Thu, Sep 14 2017, Xiao Ni wrote:
>>
>> What do
>> cat /proc/8987/stack
>> cat /proc/8983/stack
>> cat /proc/8966/stack
>> cat /proc/8381/stack
>>
>> show??
>
...
>
> /usr/sbin/mdadm --grow --continue /dev/md0. Is it the reason to add lockdep_assert_held(&mddev->reconfig_mutex)?
> [root@dell-pr1700-02 ~]# cat /proc/8983/stack
> [<ffffffffa0a3464c>] mddev_suspend+0x12c/0x160 [md_mod]
> [<ffffffffa0a379ec>] suspend_lo_store+0x7c/0xe0 [md_mod]
> [<ffffffffa0a3b7d0>] md_attr_store+0x80/0xc0 [md_mod]
> [<ffffffff812ec8da>] sysfs_kf_write+0x3a/0x50
> [<ffffffff812ec39f>] kernfs_fop_write+0xff/0x180
> [<ffffffff81260457>] __vfs_write+0x37/0x170
> [<ffffffff812619e2>] vfs_write+0xb2/0x1b0
> [<ffffffff81263015>] SyS_write+0x55/0xc0
> [<ffffffff810037c7>] do_syscall_64+0x67/0x150
> [<ffffffff81777527>] entry_SYSCALL64_slow_path+0x25/0x25
> [<ffffffffffffffff>] 0xffffffffffffffff
>
> [jbd2/md0-8]
> [root@dell-pr1700-02 ~]# cat /proc/8966/stack
> [<ffffffffa0a39b20>] md_write_start+0xf0/0x220 [md_mod]
> [<ffffffffa0972b49>] raid5_make_request+0x89/0x8b0 [raid456]
> [<ffffffffa0a34175>] md_make_request+0xf5/0x260 [md_mod]
> [<ffffffff81376427>] generic_make_request+0x117/0x2f0
> [<ffffffff81376675>] submit_bio+0x75/0x150
> [<ffffffff8129e0b0>] submit_bh_wbc+0x140/0x170
> [<ffffffff8129e683>] submit_bh+0x13/0x20
> [<ffffffffa0957e29>] jbd2_write_superblock+0x109/0x230 [jbd2]
> [<ffffffffa0957f8b>] jbd2_journal_update_sb_log_tail+0x3b/0x80 [jbd2]
> [<ffffffffa09517ff>] jbd2_journal_commit_transaction+0x16ef/0x19e0 [jbd2]
> [<ffffffffa0955d02>] kjournald2+0xd2/0x260 [jbd2]
> [<ffffffff810c73f9>] kthread+0x109/0x140
> [<ffffffff817776c5>] ret_from_fork+0x25/0x30
> [<ffffffffffffffff>] 0xffffffffffffffff
Thanks for this (and sorry it took so long to get to it).
It looks like
Commit: cc27b0c78c79 ("md: fix deadlock between mddev_suspend() and md_write_start()")
is badly broken. I wonder how it ever passed testing.
In write_start() is change the wait_event() call to
wait_event(mddev->sb_wait,
!test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags) && !mddev->suspended);
That should be
wait_event(mddev->sb_wait,
!test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags) || mddev->suspended);
i.e. it was (!A && !B), it should be (!A || B) !!!!!
Could you please make that change and try again.
Thanks,
NeilBrown
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next prev parent reply other threads:[~2017-10-05 5:17 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-12 1:49 [PATCH 0/4] RFC: attempt to remove md deadlocks with metadata without NeilBrown
2017-09-12 1:49 ` [PATCH 3/4] md: use mddev_suspend/resume instead of ->quiesce() NeilBrown
2017-09-12 1:49 ` [PATCH 1/4] md: always hold reconfig_mutex when calling mddev_suspend() NeilBrown
2017-09-12 1:49 ` [PATCH 2/4] md: don't call bitmap_create() while array is quiesced NeilBrown
2017-09-12 1:49 ` [PATCH 4/4] md: allow metadata update while suspending NeilBrown
2017-09-12 2:51 ` [PATCH 0/4] RFC: attempt to remove md deadlocks with metadata without Xiao Ni
2017-09-13 2:11 ` Xiao Ni
2017-09-13 15:09 ` Xiao Ni
2017-09-13 23:05 ` NeilBrown
2017-09-14 4:55 ` Xiao Ni
2017-09-14 5:32 ` NeilBrown
2017-09-14 7:57 ` Xiao Ni
2017-09-16 13:15 ` Xiao Ni
2017-10-05 5:17 ` NeilBrown [this message]
2017-10-06 3:53 ` Xiao Ni
2017-10-06 4:32 ` NeilBrown
2017-10-09 1:21 ` Xiao Ni
2017-10-09 4:57 ` NeilBrown
2017-10-09 5:32 ` Xiao Ni
2017-10-09 5:52 ` NeilBrown
2017-10-10 6:05 ` Xiao Ni
2017-10-10 21:20 ` NeilBrown
[not found] ` <960568852.19225619.1507689864371.JavaMail.zimbra@redhat.com>
2017-10-13 3:48 ` NeilBrown
2017-10-16 4:43 ` Xiao Ni
2017-09-30 9:46 ` Xiao Ni
2017-10-05 5:03 ` NeilBrown
2017-10-06 3:40 ` Xiao Ni
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