Update:
I tried to find a work around by using aufs.

To make a long story short: There seams to be the same issue.


mkdir /tmp/dir1 /tmp/aufs-root
mount -t aufs -o br=/tmp/dir1:/home/test,xino=/dev/shm/aufs.xino none /tmp/aufs-root

lvcreate -s -L 5G /dev/virt/opt -n vm_backup

-> Hang

dmesg

[1213440.776036] INFO: task ypbind:9957 blocked for more than 120 seconds.
[1213440.776141]       Not tainted 3.13.0-29-generic #53-Ubuntu
[1213440.776233] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[1213440.776351] ypbind          D ffff88042fc14440     0  9957   8265 0x20020000
[1213440.776357]  ffff880414fe9dd8 0000000000000002 ffff880414c547d0 ffff880414fe9fd8
[1213440.776362]  0000000000014440 0000000000014440 ffff880414c547d0 ffff880413016000
[1213440.776366]  0000000000000001 0000000000000001 0000000000000000 ffff8804130162b0
[1213440.776370] Call Trace:
[1213440.776380]  [<ffffffff8171e639>] schedule+0x29/0x70
[1213440.776386]  [<ffffffff811bee43>] __sb_start_write+0x93/0xe0
[1213440.776393]  [<ffffffff810aaea0>] ? prepare_to_wait_event+0x100/0x100
[1213440.776397]  [<ffffffff811bcb5e>] compat_do_readv_writev+0x20e/0x260
[1213440.776452]  [<ffffffffa03e2ec0>] ? xfs_file_buffered_aio_write+0x1a0/0x1a0 [xfs]
[1213440.776455]  [<ffffffff811bc030>] ? do_sync_read+0x90/0x90
[1213440.776461]  [<ffffffff8111140c>] ? acct_account_cputime+0x1c/0x20
[1213440.776465]  [<ffffffff8109d77b>] ? account_user_time+0x8b/0xa0
[1213440.776468]  [<ffffffff8109dd94>] ? vtime_account_user+0x54/0x60
[1213440.776472]  [<ffffffff811bcc57>] compat_writev+0x37/0x70
[1213440.776476]  [<ffffffff811bdd69>] compat_SyS_writev+0x49/0xa0
[1213440.776480]  [<ffffffff8172c8ec>] sysenter_dispatch+0x7/0x21
[1213440.776497] INFO: task lvcreate:28589 blocked for more than 120 seconds.
[1213440.776603]       Not tainted 3.13.0-29-generic #53-Ubuntu
[1213440.776695] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[1213440.776811] lvcreate        D ffff88042fcd4440     0 28589  24487 0x00000000
[1213440.776815]  ffff8802ce4c1bc8 0000000000000002 ffff8802ce7b0000 ffff8802ce4c1fd8
[1213440.776819]  0000000000014440 0000000000014440 ffff8802ce7b0000 ffff880413016290
[1213440.776823]  ffff8802ce4c1c00 ffff8802ce7b0000 ffff880413016218 0000000000000001
[1213440.776827] Call Trace:
[1213440.776831]  [<ffffffff8171e639>] schedule+0x29/0x70
[1213440.776835]  [<ffffffff811bef2d>] sb_wait_write+0x9d/0xb0
[1213440.776839]  [<ffffffff810aaea0>] ? prepare_to_wait_event+0x100/0x100
[1213440.776842]  [<ffffffff811bf128>] freeze_super+0x68/0x130
[1213440.776847]  [<ffffffff811f6645>] freeze_bdev+0x75/0xd0
[1213440.776853]  [<ffffffff815b6fca>] dm_suspend+0x11a/0x1e0
[1213440.776857]  [<ffffffff815bc384>] dev_suspend+0x194/0x220
[1213440.776861]  [<ffffffff815bc1f0>] ? table_load+0x350/0x350
[1213440.776864]  [<ffffffff815bcbb5>] ctl_ioctl+0x255/0x500
[1213440.776868]  [<ffffffff815bce73>] dm_ctl_ioctl+0x13/0x20
[1213440.776873]  [<ffffffff811cf9c0>] do_vfs_ioctl+0x2e0/0x4c0
[1213440.776877]  [<ffffffff8109dd94>] ? vtime_account_user+0x54/0x60
[1213440.776880]  [<ffffffff811cfc21>] SyS_ioctl+0x81/0xa0
[1213440.776885]  [<ffffffff8172adff>] tracesys+0xe1/0xe6


I wonder how no one else can suffer from this problem.
It should not be to uncommon to use LVM snapshots for backup purposes ...

Greetings,
Dirk