Description of problem:


Version-Release number of selected component (if applicable):
glusterfs-3.3.0.5rhs-40.el6rhs.x86_64
libvirt-0.9.10-21.el6_3.7.x86_64
qemu-kvm-0.12.1.2-2.295.el6_3.10.x86_64

How reproducible:
Always

Steps to Reproduce:
1. Create qcow2 image with preallocation=metadata option[1] on a gluster mount[3] and try to fallocate it.
  
Actual results:
fallocation fails with operation not supported message and the disk size is just 1.8M. However, this works as expected on the host xfs filesystem[2]. And VM installation fails when this image is specified.

Expected results:
creating gcow2 image with preallocation=metadata option should be successful.

Additional info:
[1]
[root@rhs-gp-srv11 replicate]# qemu-img create -f qcow2 -o preallocation=metadata rhsvm4-20130115.0.qcow2 10G
Formatting 'rhsvm4-20130115.0.qcow2', fmt=qcow2 size=10737418240 encryption=off cluster_size=65536 preallocation='metadata' 
[root@rhs-gp-srv11 replicate]#

[root@rhs-gp-srv11 replicate]# fallocate -l 10737418240 rhsvm4-20130115.0.qcow2 
fallocate: rhsvm4-20130115.0.qcow2: fallocate failed: Operation not supported      <<<<<<<<<<
[root@rhs-gp-srv11 replicate]# 

[root@rhs-gp-srv11 replicate]# qemu-img info rhsvm4-20130115.0.qcow2 
image: rhsvm4-20130115.0.qcow2
file format: qcow2
virtual size: 10G (10737418240 bytes)
disk size: 1.8M           <<<<<<<<<<<
cluster_size: 65536
[root@rhs-gp-srv11 replicate]# 


[2]
[root@rhs-gp-srv11 rhsvm4-20130115.0]# qemu-img create -f qcow2 -o preallocation=metadata rhsvm4-20130115.0.qcow2 10G
Formatting 'rhsvm4-20130115.0.qcow2', fmt=qcow2 size=10737418240 encryption=off cluster_size=65536 preallocation='metadata' 

[root@rhs-gp-srv11 rhsvm4-20130115.0]# fallocate -l 10737418240 rhsvm4-20130115.0.qcow2 

[root@rhs-gp-srv11 rhsvm4-20130115.0]# qemu-img info rhsvm4-20130115.0.qcow2 
image: rhsvm4-20130115.0.qcow2
file format: qcow2
virtual size: 10G (10737418240 bytes)
disk size: 17G
cluster_size: 65536
[root@rhs-gp-srv11 rhsvm4-20130115.0]# 


[3]
[root@rhs-gp-srv11 ~]# mount
/dev/mapper/VolGroup-lv_root on / type ext4 (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
tmpfs on /dev/shm type tmpfs (rw,rootcontext="system_u:object_r:tmpfs_t:s0")
/dev/sda1 on /boot type ext4 (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
/dev/mapper/sdm_lvm_grp-sdm_vol1 on /home/rhsvms/rhsvm1 type xfs (rw)
/dev/mapper/sdl_lvm_grp-sdl_vol1 on /home/rhsvms/rhsvm2 type xfs (rw)
/dev/mapper/sdn_lvm_grp-sdn_vol1 on /home/rhsvms/rhsvm3 type xfs (rw)
rhsvm1:replicate on /vmstore/replicate type fuse.glusterfs (rw,default_permissions,allow_other,max_read=131072)
rhsvm1:distribute on /vmstore/distribute type fuse.glusterfs (rw,default_permissions,allow_other,max_read=131072)
/dev/mapper/sdk_lvm_grp-sdk_vol1 on /home/rhsvms/rhsvm4-20130115.0 type xfs (rw)
[root@rhs-gp-srv11 ~]#


[4]
# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root
                       29G  5.7G   22G  21% /
tmpfs                  24G     0   24G   0% /dev/shm
/dev/sda1             485M   59M  401M  13% /boot
/dev/mapper/sdm_lvm_grp-sdm_vol1
                      450G  134G  317G  30% /home/rhsvms/rhsvm1
/dev/mapper/sdl_lvm_grp-sdl_vol1
                      450G   83G  368G  19% /home/rhsvms/rhsvm2
/dev/mapper/sdn_lvm_grp-sdn_vol1
                      100G   83G   18G  83% /home/rhsvms/rhsvm3
rhsvm1:replicate       50G  1.1G   49G   3% /vmstore/replicate
rhsvm1:distribute     150G   26G  125G  17% /vmstore/distribute
/dev/mapper/sdk_lvm_grp-sdk_vol1
                      450G   17G  434G   4% /home/rhsvms/rhsvm4-20130115.0