[linux-lvm] Re: Error on unmounting XFS LVM snapshot

[Ronny Adsetts <ronny.adsetts@amazinginternet.com>]

Murthy Kambhampaty said the following on 20/10/03 18:10:
 >>-----Original Message-----
 >>From: Ronny Adsetts [mailto:ronny.adsetts@amazinginternet.com]
 >>Sent: Friday, October 17, 2003 12:39
 >>
 >>Software used:
 >>Debian: 3.0 (Mostly)
 >>Kernel: 2.4.21
 >>Kernel patches: Debian standard kernel patches; XFS 1.3.0
 >>LVM utils: 1.0.4-4 (Debian)
 >>XFS utils: 2.5.6-1 (Debian)
 >>
 >>Sequence of actions:
 >>1: xfs_freeze -f /home
 >>2: lvcreate -L 1G -s -n home_lv_bak /dev/vg0/home_lv
 >>3: xfs_freeze -u /home
 >>4: mount -t xfs -onouuid,ro,usrquota /dev/vg0/home_lv_bak /mnt/home
 >>5: umount /mnt/home
 >>6: lvremove -f /dev/vg0/home_lv_bak
 >>
 >>On step 5 of above, an error is logged:
 >>
 >>Logs:
 >>Oct 17 17:23:44 jettero kernel: lvm - lvm_map: ll_rw_blk write for
 >>readonly LV /dev/vg0/home_lv_bak
 >>Oct 17 17:23:44 jettero kernel: xfs_force_shutdown(lvm(58,10),0x1)
 >>called from line 351 of file xfs_rw.c.  Return address = 0xc01fd6aa
 >>Oct 17 17:23:44 jettero kernel: Filesystem "lvm(58,10)": I/O Error
 >>Detected.  Shutting down filesystem: lvm(58,10)
 >>Oct 17 17:23:44 jettero kernel: Please umount the filesystem, and
 >>rectify the problem(s)
 >
> I got these error messages on the Wolk 4.9s kernel, but not on XFS CVS
> kernels (or vanilla linux with XFS patches applied). This is a somewhat
> random guess, but you might try to upgrade LVM to 1.0.7, following the LVM
> how-to, and see if the problem persists.
> 

I've built a later version of LVM 1 tools, but not had a chance to try 
them yet (probably won't bother now).

I did see this this today which appears to be the same issue:

http://www.kerneltraffic.org/kernel-traffic/kt20031027_238.html#4

 From Marcelo Tosatti[1]: "It seems its not safe to create snapshots of 
journalled fs'es without this patch[2]."

Looks like the patch will show up in mainline in the 2.4.24-pre series.

[1] http://marc.theaimsgroup.com/?l=linux-kernel&m=106642797513724&w=2
[2] http://marc.theaimsgroup.com/?l=linux-kernel&m=106623350522639&q=p3

Regards,
Ronny
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