Re: ext4+quota+nfs issue

[Jan Kara <jack@suse.cz>]

On Wed 09-09-09 11:42:03, Jiri Kosina wrote:
> [ adding relevant CCs ]
  Thanks.

> On Wed, 9 Sep 2009, Pavol Cvengros wrote:
> > > recently we have build and started to use raid storage with formatted
> > > capacity of 4.5T (ext4 formatted, default params).
> > > FS has quota turned on and is exported via NFS to nodes.
> > > If we turn qouta on on this FS and are trying to use it over NFS we get the
> > > following:
> > > 
> > > ------------[ cut here ]------------
> > > WARNING: at fs/quota/dquot.c:964 dquot_claim_space+0x181/0x190()
> > > Hardware name: S3210SH
> > > Modules linked in: nfs fscache nfsd lockd auth_rpcgss exportfs sunrpc
> > > coretemp hwmon ipmi_si ipmi_msghandler ehci_hcd sr_mod cdrom uhci_hcd floppy
> > > usbcore i2c_i801 i2c_core processor 3w_9xxx button thermal
> > > Pid: 268, comm: pdflush Tainted: G        W  2.6.30-gentoo-r3_host #1
> > > Call Trace:
> > >  [<ffffffff803151e1>] ? dquot_claim_space+0x181/0x190
> > >  [<ffffffff80245c59>] ? warn_slowpath_common+0x89/0x100
> > >  [<ffffffff803151e1>] ? dquot_claim_space+0x181/0x190
> > >  [<ffffffff80367e83>] ? ext4_mb_mark_diskspace_used+0x423/0x440
> > >  [<ffffffff8036c05f>] ? ext4_mb_new_blocks+0x2cf/0x460
> > >  [<ffffffff80360a17>] ? ext4_ext_find_extent+0x307/0x330
> > >  [<ffffffff80362508>] ? ext4_ext_get_blocks+0x578/0xfc0
> > >  [<ffffffff8028e828>] ? __pagevec_free+0x48/0x70
> > >  [<ffffffff803a1c65>] ? blk_rq_bio_prep+0x35/0x130
> > >  [<ffffffff8034d310>] ? ext4_get_blocks_wrap+0x210/0x380
> > >  [<ffffffff8034d8d8>] ? mpage_da_map_blocks+0xe8/0x750
> > >  [<ffffffff80292cee>] ? pagevec_lookup_tag+0x2e/0x50
> > >  [<ffffffff8029084c>] ? write_cache_pages+0x11c/0x400
> > >  [<ffffffff8034e500>] ? __mpage_da_writepage+0x0/0x190
> > >  [<ffffffff8034e269>] ? ext4_da_writepages+0x329/0x4b0
> > >  [<ffffffff80290bd2>] ? do_writepages+0x32/0x70
> > >  [<ffffffff802e4140>] ? __writeback_single_inode+0xb0/0x490
> > >  [<ffffffff8023c753>] ? dequeue_entity+0x23/0x1c0
> > >  [<ffffffff802e4b16>] ? generic_sync_sb_inodes+0x316/0x4f0
> > >  [<ffffffff802e4f4e>] ? writeback_inodes+0x5e/0x110
> > >  [<ffffffff80290e56>] ? wb_kupdate+0xc6/0x160
> > >  [<ffffffff80292110>] ? pdflush+0x120/0x230
> > >  [<ffffffff80290d90>] ? wb_kupdate+0x0/0x160
> > >  [<ffffffff80291ff0>] ? pdflush+0x0/0x230
> > >  [<ffffffff80261154>] ? kthread+0x64/0xc0
> > >  [<ffffffff8020d13a>] ? child_rip+0xa/0x20
> > >  [<ffffffff802610f0>] ? kthread+0x0/0xc0
> > >  [<ffffffff8020d130>] ? child_rip+0x0/0x20
> > > ---[ end trace cb54e6523e9ab60d ]---
> > > 
> > > fstab entry:
> > > /dev/sdb1              /mnt/storage    ext4
> > > noatime,nodiratime,usrjquota=aquota.user,grpjquota=aquota.group,jqfmt=vfsv0 
> > > 
> > > qith quotaoff on tihs FS, warnings stop.
> > > 
> > > Question is if it's safe to use quotas with this problem (warning) or not.
> > > Can't afford data damage.
  The warning definitely doesn't directly indicate a danger of data loss.
But there *is* some bug causing that ext4 asks for more quota space than
it has reserved.
  From your report it seems it is easily reproducible, right? Do you have
an easy way to trigger this warning - by some test script or so?

								Honza
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR