[PATCH] [RESEND] Don't mount raw blktap disks for pygrub

[PATCH] [RESEND] Don't mount raw blktap disks for pygrub

[Mark McLoughlin]

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(Doesn't seem to be in the staging tree; re-sending just in case it
slipped through the cracks)

Hi,
	Currently, we mount all blktap disks for pygrub so that it can boot
from e.g. QCOW images. However, since pygrub will handle a raw image
just fine without mounting through blktap, we shouldn't bother in that
case.

	Also, it looks like XendDomainInfo.create_vbd() takes the full disk
uname rather than the image path.

  Signed-off-by: Mark McLoughlin <markmc@redhat.com>

Cheers,
Mark.

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diff -r 3ac19fda0bc2 tools/python/xen/util/blkif.py
--- a/tools/python/xen/util/blkif.py	Fri Mar 02 12:11:52 2007 +0000
+++ b/tools/python/xen/util/blkif.py	Mon Mar 05 10:06:00 2007 +0000
@@ -66,16 +66,23 @@ def blkdev_segment(name):
                 'type'         : 'Disk' }
     return val
 
-def blkdev_uname_to_file(uname):
-    """Take a blkdev uname and return the corresponding filename."""
-    fn = None
+def _parse_uname(uname):
+    fn = taptype = None
     if uname.find(":") != -1:
         (typ, fn) = uname.split(":", 1)
         if typ == "phy" and not fn.startswith("/"):
             fn = "/dev/%s" %(fn,)
         if typ == "tap":
-            (typ, fn) = fn.split(":", 1)
-    return fn
+            (taptype, fn) = fn.split(":", 1)
+    return (fn, taptype)
+
+def blkdev_uname_to_file(uname):
+    """Take a blkdev uname and return the corresponding filename."""
+    return _parse_uname(uname)[0]
+
+def blkdev_uname_to_taptype(uname):
+    """Take a blkdev uname and return the blktap type."""
+    return _parse_uname(uname)[1]
 
 def mount_mode(name):
     mode = None
diff -r 3ac19fda0bc2 tools/python/xen/xend/XendDomainInfo.py
--- a/tools/python/xen/xend/XendDomainInfo.py	Fri Mar 02 12:11:52 2007 +0000
+++ b/tools/python/xen/xend/XendDomainInfo.py	Mon Mar 05 10:30:06 2007 +0000
@@ -34,7 +34,7 @@ from types import StringTypes
 
 import xen.lowlevel.xc
 from xen.util import asserts
-from xen.util.blkif import blkdev_uname_to_file
+from xen.util.blkif import blkdev_uname_to_file, blkdev_uname_to_taptype
 from xen.util import security
 
 from xen.xend import balloon, sxp, uuid, image, arch, osdep
@@ -1768,7 +1768,8 @@ class XendDomainInfo:
             disk = devinfo[1]['uname']
 
             fn = blkdev_uname_to_file(disk)
-            mounted = devtype == 'tap' and not os.stat(fn).st_rdev
+            taptype = blkdev_uname_to_taptype(disk)
+            mounted = devtype == 'tap' and taptype != 'aio' and taptype != 'sync' and not os.stat(fn).st_rdev
             if mounted:
                 # This is a file, not a device.  pygrub can cope with a
                 # file if it's raw, but if it's QCOW or other such formats
@@ -1784,7 +1785,7 @@ class XendDomainInfo:
 
                 from xen.xend import XendDomain
                 dom0 = XendDomain.instance().privilegedDomain()
-                dom0._waitForDeviceUUID(dom0.create_vbd(vbd, fn))
+                dom0._waitForDeviceUUID(dom0.create_vbd(vbd, disk))
                 fn = BOOTLOADER_LOOPBACK_DEVICE
 
             try:

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Re: [PATCH] [RESEND] Don't mount raw blktap disks for pygrub

[Andrew Warfield]

What is the broken thing that you are trying to fix with this patch?
The current code works fine and treats all tap-based devices equally,
while this new code special-cases certain tap-based drivers (aio and
sync).

a.

On 3/7/07, Mark McLoughlin <markmc@redhat.com> wrote:
> (Doesn't seem to be in the staging tree; re-sending just in case it
> slipped through the cracks)
>
> Hi,
>         Currently, we mount all blktap disks for pygrub so that it can boot
> from e.g. QCOW images. However, since pygrub will handle a raw image
> just fine without mounting through blktap, we shouldn't bother in that
> case.
>
>         Also, it looks like XendDomainInfo.create_vbd() takes the full disk
> uname rather than the image path.
>
>   Signed-off-by: Mark McLoughlin <markmc@redhat.com>
>
> Cheers,
> Mark.
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
>
>
>