[Qemu-stable] qcow2 file seems to be corrupted

[Vladimir Melnik]

Dear colleagues,

I encountered some very strange issue and would be grateful if you share
your thoughts on that.

I have a qcow2-image that is located at gfs2 filesystem on a cluster.
The cluster works fine and there are dozens of other qcow2-images, but,
as I can see, one of images seems to be corrupted.

First of all, it has quite unusual size:
> stat /mnt/sp1/ac2cb28f-09ac-4ca0-bde1-471e0c7276a0.bak
  File: `/mnt/sp1/ac2cb28f-09ac-4ca0-bde1-471e0c7276a0.bak'
  Size: 7493992262336241664     Blocks: 821710640  IO Block: 4096   regular file
Device: fd06h/64774d    Inode: 220986752   Links: 1
Access: (0744/-rwxr--r--)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2014-10-09 16:25:24.864877839 +0300
Modify: 2014-12-13 14:41:29.335603509 +0200
Change: 2014-12-13 15:52:35.986888549 +0200

By the way, I noticed that blocks' number looks rather okay.

Also qemu-img can't recognize it as an image:
> qemu-img info /mnt/sp1/ac2cb28f-09ac-4ca0-bde1-471e0c7276a0.bak
image: /mnt/sp1/ac2cb28f-09ac-4ca0-bde1-471e0c7276a0.bak
file format: raw
virtual size: 6815746T (7493992262336241664 bytes)
disk size: 392G

Disk size, although, looks more reasonable: the image's size is really
should be about 300-400G, as I remember.

Alas, I can't do anything with this image. I can't check it by qemu-img,
neither I can convert it to the new image, as qemu-img can't do anything
with it:

> qemu-img convert -p -f qcow2 -O qcow2 
> /mnt/sp1/ac2cb28f-09ac-4ca0-bde1-471e0c7276a0.bak 
> /mnt/tmp/ac2cb28f-09ac-4ca0-bde1-471e0c7276a0
Could not open '/mnt/sp1/ac2cb28f-09ac-4ca0-bde1-471e0c7276a0.bak': Invalid 
argument
Could not open '/mnt/sp1/ac2cb28f-09ac-4ca0-bde1-471e0c7276a0.bak'

Any one have experienced the same issue? What do you think, is it qcow2
issue or a gfs2 issue? What would you do in similar situation?

Any ideas, hints and comments would be greatly appreciated.

Yes, I have snapshots, that's good, but wouldn't like to lose today's
changes to the data on that image. And I'm worried about the filesystem
at all: what if something goes wrong if I try to remove that file?

Thanks to all!


-- 
V.Melnik

P.S. I use CentOS-6 and I have these packages installed:
        qemu-img-0.12.1.2-2.415.el6_5.4.x86_64
        gfs2-utils-3.0.12.1-59.el6_5.1.x86_64
        lvm2-cluster-2.02.100-8.el6.x86_64
        cman-3.0.12.1-59.el6_5.1.x86_64
        clusterlib-3.0.12.1-59.el6_5.1.x86_64
        kernel-2.6.32-431.5.1.el6.x86_64