Description of problem:

I am trying to do my database testing with raw devices. I defined devices as follows

.
.
.
<disk type='block' device='disk'>
      <source dev='/dev/perfvg/system_001'/>
      <target dev='vdz' bus='virtio'/>
    </disk>
    <disk type='block' device='disk'>
      <source dev='/dev/perfvg/temp_0_0'/>
      <target dev='vdaa' bus='virtio'/>
    </disk>
    <disk type='block' device='disk'>
      <source dev='/dev/perfvg/undo_sys_ts.dbf'/>
      <target dev='vdab' bus='virtio'/>
    </disk>
    <disk type='block' device='disk'>
      <source dev='/dev/perfvg/ware_0_0'/>
      <target dev='vdac' bus='virtio'/>
    </disk>
.
.
.


But in my guest I see devices only upto vdz. The vdaa, vdab and vdac devices were not created.

After exchanging emails, it was narrowed down to libvirt code.

src/util.c::virDiskNameToIndex()
    int idx = 0;
...
    while (*ptr) {
        idx = idx * 26;

        if (!c_islower(*ptr))
            return -1;

        idx += *ptr - 'a';  <-- looks broken here
        ptr++;
    }





Version-Release number of selected component (if applicable):


How reproducible:

Readily reproducible

Steps to Reproduce:
1. Create KVM guest with raw devices exceeding vdz  (eg vdaa, ..
2. Start guest and devices are created only upto vdz
3.
  
Actual results:


Expected results:


Additional info: