On Tue, Aug 05, 2008 at 12:12:21PM +0200, Chris Lalancette wrote:
Recently upstream Xen added support for having xvd devices > 16. For the most part, this doesn't really concern libvirt, since for things like attach and detach we just pass it through and let xend worry about whether it is supported or not. The one place this breaks down is in the stats collecting code, where we need to figure out the device number so we can go digging in /sys for the statistics.
To remedy this, I've re-written xenLinuxDomainDeviceID() to use regular expressions to figure out the device number from the name. The major advantage is that now xenLinuxDomainDeviceID() looks fairly identical to tools/python/xen/util/blkif.py (in the Xen sources), so that adding additional devices in the future should be much easier. It also reduces the size of the code, and, in my opinion, the code complexity.
With this patch in place, I was able to get block statistics both on older style devices (/dev/xvda) and on the new, expanded devices (/dev/xvdaa).
This patch breaks the test suite for disk name -> device ID conversion. The test suite also needs to have more tests added to cover the new interesting boundary conditions for xvdXXX naming.
- if (strlen (path) >= 4 && - STRPREFIX (path, "xvd")) { - /* Xen paravirt device handling */ - disk = (path[3] - 'a'); - if (disk < 0 || disk > 15) { - statsErrorFunc (conn, VIR_ERR_INVALID_ARG, __FUNCTION__, - "invalid path, device names must be in range xvda - xvdp", - domid); - return -1; - }
I don't like the fact that for 'out of range' values this patch is removing this accurate and helpful error message.....
- return (majors[disk/2] * 256) + ((disk % 2) * 63) + part; + if (disk_re_match("/dev/sd[a-z]([1-9]|1[0-5])?$", mod_path, &part)) { + major = scsi_majors[(mod_path[7] - 'a') / 16]; + minor = ((mod_path[7] - 'a') % 16) * 16 + part; + retval = major * 256 + minor; } + else if (disk_re_match("/dev/sd[a-i][a-z]([1-9]|1[0-5])?$", + mod_path, &part)) { + major = scsi_majors[((mod_path[7] - 'a' + 1) * 26 + (mod_path[8] - 'a')) / 16]; + minor = (((mod_path[7] -'a' + 1) * 26 + (mod_path[8] - 'a')) % 16) + * 16 + part; + retval = major * 256 + minor; + } + else if (disk_re_match("/dev/hd[a-t]([1-9]|[1-5][0-9]|6[0-3])?", + mod_path, &part)) { + major = ide_majors[(mod_path[7] - 'a') / 2]; + minor = ((mod_path[7] - 'a') % 2) * 64 + part; + retval = major * 256 + minor; + } + else if (disk_re_match("/dev/xvd[a-p]([1-9]|1[0-5])?$", mod_path, &part)) + retval = (202 << 8) + ((mod_path[8] - 'a') << 4) + part; + else if (disk_re_match("/dev/xvd[q-z]([1-9]|1[0-5])?$", mod_path, &part)) + retval = (1 << 28) + ((mod_path[8] - 'a') << 8) + part; + else if (disk_re_match("/dev/xvd[a-i][a-z]([1-9]|1[0-5])?$", + mod_path, &part)) + retval = (1 << 28) + (((mod_path[8] - 'a' + 1) * 26 + (mod_path[9] - 'a')) << 8) + part; + else + statsErrorFunc (conn, VIR_ERR_INVALID_ARG, __FUNCTION__, + "unsupported path, use xvdN, hdN, or sdN", domid);
...and replacing it with this unhelpful & misleading one. Daniel -- |: Red Hat, Engineering, London -o- http://people.redhat.com/berrange/ :| |: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|