Re: BUG: enabling psacct breaks fsfreeze

From: Jan Kara
Date: Wed Nov 07 2012 - 13:51:32 EST


On Thu 01-11-12 23:50:53, Jan Kara wrote:
> 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.
OK, can you test attached patch?

Honza

--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR