Hello, When I run lvcreate -L1G -n backup -s /dev/gentoo/root to create a snapshot of my root partition, the process hangs. I can only stop my computer with SysRq keys. When I restart the computer, the volume seems to have been created but it is not listed as a snapshot. I have tried LVM 2.02.70 and 2.02.72 and the problem occur with these 2 versions. I am using udev 160. Does anybody know what's happening ? With kernel 2.6.34.2, everything works correctly. Thanks in advance for your help.
Try to supply some diagnostics - e.g. the process backtraces sysrq will show and 'lvmdump' after rebooting.
Created attachment 27372 [details] Output of lvmdump So here is the output of lvmdump after having restarted the computer.
So, the logical volume is well created but it's not a snapshot. When I try to mount it, I get the following error: mount: unknown filesystem type 'DM_snapshot_cow' zsh: exit 32 LC_ALL='C' mount /dev/gentoo/backup /mnt/backup
I noticed that this problem occurs when I take a snapshot of the root partition. I also tried git bisect but it doesn't reveals anything conclusive. The first bad commit is supposed to be the following: f3b99be19ded511a1bf05a148276239d9f13eefa is the first bad commit commit f3b99be19ded511a1bf05a148276239d9f13eefa Author: NeilBrown <neilb@suse.de> Date: Thu Jun 24 13:31:03 2010 +1000 Restore partition detection of newly created md arrays. However, I don't use RAID but only LVM so this is not the real first bad commit.
Created attachment 27375 [details] Output of strace when running lvcreate Maybe you will find the output of strace interesting. Unfortunately, this is so long that I can only get the end. This is thus the result of
I did something wrong. So, the strace is the result of strace lvcreate -L1G -n backup -s /dev/gentoo/root. Since it completely fills the console, I only have the end of it.
I finally find the problematic commit with git-bisect. This is the following one: commit 6b0310fbf087ad6e9e3b8392adca97cd77184084 Author: Eric Sandeen <sandeen@redhat.com> Date: Sun May 16 02:00:00 2010 -0400 ext4: don't return to userspace after freezing the fs with a mutex held If I revert it, the problem doesn't occur.
This problem is in fact fixed by the following commit: commit d2aa412a7e270bc679a586dda415344f2b8ad01e Author: Eric Sandeen <sandeen@sandeen.net> Date: Sun Aug 1 17:33:29 2010 -0400 ext4: fix freeze deadlock under IO