Description of problem: when I try to snapshot my root lv it hangs here: ========================================================================== [root@RAWHIDE ~]# lvcreate -v -s -n snaproot -L 100M /dev/mainvg/rootlv Setting chunksize to 8 sectors. Setting logging type to disk Finding volume group "mainvg" Archiving volume group "mainvg" metadata (seqno 114). Creating logical volume snaproot Creating volume group backup "/etc/lvm/backup/mainvg" (seqno 115). Found volume group "mainvg" Creating mainvg-snaproot Loading mainvg-snaproot table (253:2) Resuming mainvg-snaproot (253:2) Clearing start of logical volume "snaproot" Creating logical volume snapshot0 Found volume group "mainvg" Found volume group "mainvg" Creating mainvg-rootlv-real Loading mainvg-rootlv-real table (253:3) Resuming mainvg-rootlv-real (253:3) Loading mainvg-rootlv table (253:0) Creating mainvg-snaproot-cow Loading mainvg-snaproot-cow table (253:4) Resuming mainvg-snaproot-cow (253:4) Loading mainvg-snaproot table (253:2) Suspending mainvg-rootlv (253:0) with filesystem sync with device flush ========================================================================= I/O on the system is then blocked and reboot needed. lv's other than the root lv I can successfully snapshot. Version-Release number of selected component (if applicable): kernel-2.6.35-0.2.rc3.git0.fc14.x86_64 lvm2-2.02.67-1.fc14.x86_64 device-mapper-1.02.49-1.fc14.x86_64 Additional info: If I revert back to kernel-2.6.34-20.fc14.x86_64, snapshots of my root lv are successful again. This install is running in a qemu-kvm if that matters.
This is probably problem described here https://www.redhat.com/archives/dm-devel/2010-June/msg00084.html Reassigning to kernel, according the thread, reverting 6b0310fbf087ad6 fixes the problem.
Yeah, this one's mine. It doesn't have to be the root, I think, any volume w/ active IO may hit this, sadly.
I sent a patch upstream (linux-fsdevel & linux-ext4) for this, there seem to be other deadlocks lurking but this should fix up the egregious one I introduced. [PATCH] ext4: fix freeze deadlock under IO I'll toss it into rawhide for testing.
s/b fixed in 2.6.35-0.15.rc3.git3 pls test & re-open if you still have trouble. Thanks, -Eric