Bug 175682

Summary:	lvrename hangs on snapshot volume
Product:	Red Hat Enterprise Linux 4	Reporter:	David Milburn <dmilburn>
Component:	kernel	Assignee:	Alasdair Kergon <agk>
Status:	CLOSED WORKSFORME	QA Contact:	Brian Brock <bbrock>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	4.0	CC:	jbaron, jbrassow, tao
Target Milestone:	---
Target Release:	---
Hardware:	i686
OS:	Linux
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Fixed In Version:		Doc Type:	Bug Fix
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Clone Of:		Environment:
Last Closed:	2006-03-03 18:35:24 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Embargoed:

Description David Milburn 2005-12-13 23:00:06 UTC

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Description of problem:
Renaming a LVM snapshot causes the lvrename process to hang, it cannot be killed with Ctrl-c, it also prevents the system from being rebooted with "/sbin/reboot" or "/sbin/shutdown -r".

This problem has been reported on the 2.6.10 kernel. 

See: http://www.redhat.com/archives/dm-devel/2005-January/msg00000.html


Version-Release number of selected component (if applicable):
kernel-smp-2.6.9-22.0.1.EL

How reproducible:
Always

Steps to Reproduce:
1. pvcreate /dev/sda1
2. vgcreate testvg /dev/sda1
3. lvcreate -L10G -n test testvg
4. mke2fs -j /dev/mapper/testvg-test
5. mount /dev/mapper/testvg-test /mnt
6. lvcreate -s -l 128 -n test_backup testvg/test
7. lvrename testvg test_backup test_backup.tmp

  

Actual Results:  The lvrename command hangs, and the system cannot be rebooted.

Expected Results:  Should be able to rename the snapshot.


Additional info:

Here is sysrq-t data for lvrename when it is in the hung state.

lvrename      D DEA119B0  2196  4073   4034                     (NOTLB)
d0170ec0 00200082 d5a50c80 dea119b0 c02232e4 013ffff8 00000000 00000008
       ce213f00 00200046 c1417d60 00000002 00040650 4b7aa2bf 00000039 dfeb0b30
       dd67c2b0 dd67c41c e082f8af 00000008 c1417d60 c043af00 dfe1c580 d0170ecc
Call Trace:
 [<c02232e4>] generic_make_request+0x18e/0x19e
 [<e082f8af>] dm_unplug_all+0x17/0x21 [dm_mod]
 [<c02cf67b>] io_schedule+0x26/0x30
 [<c015ac10>] __wait_on_buffer+0x6c/0x83
 [<c015aab8>] bh_wake_function+0x0/0x29
 [<c015d8cd>] submit_bh+0x15a/0x166
 [<c015aab8>] bh_wake_function+0x0/0x29
 [<c015d9ef>] sync_dirty_buffer+0xa4/0xd4
 [<e08bd93f>] ext3_unlockfs+0x51/0x73 [ext3]
 [<c015af0c>] thaw_bdev+0x28/0x61
 [<e0830061>] unlock_fs+0x14/0x35 [dm_mod]
 [<e08302f8>] dm_resume+0xbb/0xe5 [dm_mod]
 [<e0832d0e>] do_resume+0x150/0x170 [dm_mod]
 [<e0833c93>] ctl_ioctl+0xd1/0x144 [dm_mod]
 [<e0832d2e>] dev_suspend+0x0/0x10 [dm_mod]
 [<c0169902>] sys_ioctl+0x227/0x269
 [<c02d0fb7>] syscall_call+0x7/0xb
 [<c02d007b>] __lock_text_end+0x232/0x100f

Comment 1 Jonathan Earl Brassow 2005-12-14 20:18:24 UTC

works for me on 2.6.9-25.EL

It seems to work on older kernels too, but more extensive testing is blocked by other snapshot bugs in 
earlier kernels

Comment 2 Alasdair Kergon 2005-12-14 21:20:14 UTC

The rename code has changed in U3 (does fewer dm ioctls), so any attempt at
reproducing this the same failure should use an older lvm2 package.

If it can be reproduced with the new lvm2 package on the latest U3 kernel, then
it is likely to be the same as bug 174636.  (Both lock up inside filesystem syncs.)

Comment 3 David Milburn 2005-12-16 20:02:57 UTC

Previously, I had reproduced the problem on a system running 2.6.9-22.0.1.ELsmp
and lvm2-2.01.14-2.0.RHEL4. I upgraded to 2.6.9-25.ELsmp and was able to
reproduce the hang. But after upgrading to lvm2-2.02-01-1.1.RHEL4, I was no
longer able to reproduce the hang running the 2.6.9-25.ELsmp kernel.

Comment 4 Corey Marthaler 2006-02-02 22:28:58 UTC

FYI: this works for me with the latest and greatest lvm2/device-mapper. 
I'll add a check for this in the regression tests though.