From: Marco Stornelli <marco.stornelli@gmail.com>
To: Jan Kara <jack@suse.cz>
Cc: Nikola Ciprich <nikola.ciprich@linuxbox.cz>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: BUG: enabling psacct breaks fsfreeze
Date: Fri, 02 Nov 2012 10:50:50 +0100 [thread overview]
Message-ID: <5093977A.9010507@gmail.com> (raw)
In-Reply-To: <20121101225053.GB31937@quack.suse.cz>
Il 01/11/2012 23:50, Jan Kara ha scritto:
> On Thu 01-11-12 15:23:25, Nikola Ciprich wrote:
>> Nov 1 14:23:25 vmnci22 [ 1075.178123] SysRq : Show Blocked State
>> Nov 1 14:23:25 vmnci22 [ 1075.180555] task PC stack pid father
>> Nov 1 14:23:25 vmnci22 [ 1075.180592] fsfreeze D 0000000000000000 0 4215 4195 0x00000000
>> Nov 1 14:23:25 vmnci22 [ 1075.180599] ffff8800090b9b28 0000000000000046 0000000000000000 ffffffff00000000
>> Nov 1 14:23:25 vmnci22 [ 1075.180606] 0000000000013780 ffff8800090b9fd8 ffff88000f716170 ffff88000f715e80
>> Nov 1 14:23:25 vmnci22 [ 1075.180612] ffff88000f715dc0 ffffffff81566080 ffff88000f716170 000000010002f405
>> Nov 1 14:23:25 vmnci22 [ 1075.180619] Call Trace:
>> Nov 1 14:23:25 vmnci22 [ 1075.180693] [<ffffffff810e2dbb>] __generic_file_aio_write+0xbb/0x420
>> Nov 1 14:23:25 vmnci22 [ 1075.180729] [<ffffffff81079290>] ? autoremove_wake_function+0x0/0x40
>> Nov 1 14:23:25 vmnci22 [ 1075.180736] [<ffffffff810e317f>] generic_file_aio_write+0x5f/0xc0
> Thanks. So the system isn't really deadlocked. It's just that fsfreeze
> command hangs, isn't it? OK, I understand that it's kind of incovenient
> situation because every command will hang like this when the filesystem is
> frozen.
>
> Now I only have to come up with a way to improve this... It isn't quite
> simple - to properly protect against freezing be have to communicate down
> into generic_file_aio_write() that we want to bail out if filesystem is
> frozen instead of waiting.
>
> Honza
>
I saw this behavior (task-hang) when I tested the fsfreeze code. I was
writing a little patch to replace fsfreeze's wait queue with a killable
queue, in this way the user can do at least "kill -9", but since the
behavior was the same before your patch I didn't send it. I don't know
if we can break any previous behavior. The funny thing here is that it's
like if fsfreeze freezes itself :)
Marco
next prev parent reply other threads:[~2012-11-02 9:50 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-23 9:43 BUG: enabling psacct breaks fsfreeze Nikola Ciprich
2012-10-31 12:15 ` Jan Kara
2012-10-31 12:46 ` Nikola Ciprich
2012-11-01 9:37 ` Jan Kara
2012-11-01 11:19 ` Jan Kara
2012-11-01 14:23 ` Nikola Ciprich
2012-11-01 22:50 ` Jan Kara
2012-11-02 9:50 ` Marco Stornelli [this message]
2012-11-02 10:40 ` Nikola Ciprich
2012-11-03 8:22 ` Marco Stornelli
2012-11-07 18:51 ` Jan Kara
2012-11-07 21:21 ` Nikola Ciprich
2012-11-07 22:32 ` Jan Kara
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