Daniel P. Berrange wrote:
> On Mon, Aug 11, 2008 at 03:58:41PM -0400, Cole Robinson wrote:
>
>> The patch below implements virStorageVolDelete for volumes
>> on a disk pool.
>>
>> The only interesting thing here is that parted wants a
>> partition number to delete, so we need to peel off the
>> end of the volume's target path which will be of the form
>> '/dev/sda1' or similar (I assume. If not, it's still
>> better than having nothing implemented).
>>
>> Thanks,
>> Cole
>>
>> {
>> - /* delete a partition */
>> - virStorageReportError(conn, VIR_ERR_NO_SUPPORT,
>> - _("Disk pools are not yet supported"));
>> - return -1;
>> + char *part_num = NULL;
>> + int i;
>> +
>> + /* Strip target path (ex. '/dev/sda1') of its partition number */
>> + for (i = (strlen(vol->target.path)-1); i >= 0; --i) {
>> + if (!c_isdigit(vol->target.path[i]))
>> + break;
>> + part_num = &(vol->target.path[i]);
>> + }
>> +
>> + if (!part_num) {
>> + virStorageReportError(conn, VIR_ERR_INTERNAL_ERROR,
>> + _("cannot parse partition number from target "
>> + "path '%s'"), vol->target.path);
>> + return -1;
>> + }
>>
>
> This isn't correct because the target path is not guarenteed to point to
> the master device name /dev/sda1. The user could have configured it to
> use a stable path such as /dev/disk/by-uuid/4cb23887-0d02-4e4c-bc95-7599c85afc1a
>
>
Hmm, I couldn't actually get /dev/disk/by-uuid to work. Seems like the
vol populating code for disks doesn't take into account the the pools
target path, and just uses the real partition path.
> So, you need to first call 'readlink' on the vol->target.path, ignoring
> EINVAL which you'll get if it wasn't a symlink. Once you've done that
> you'll need to validate that it is sane by checking that vol->source.devices[0]
> is a prefix of the resolved pathname. Finally, you can extract the partition
> number. So something along the lines of
>
> char devname[PATH_MAX];
>
> if (readlink(vol->target.path, devname, sizeof(devname)) < 0 &&
> errno != EINVAL)
> virStorageReportError(...)
>
> if (!STRPREFIX(devname, vol->source.devices[0].path))
> virStorageReportError(....)
>
> part_num = devname + strlen(vol->source.devices[0].path)
>
The attached patch uses this approach. It works for the case with
vols of the form /dev/sdx123, but as mentioned above I couldn't
get by-uuid method to work, so can't be certain about that.
Thanks,
Cole
diff --git a/src/storage_backend_disk.c b/src/storage_backend_disk.c
index 31a35b5..889ed66 100644
--- a/src/storage_backend_disk.c
+++ b/src/storage_backend_disk.c
@@ -22,6 +22,7 @@
*/
#include <config.h>
+#include <string.h>
#include "internal.h"
#include "storage_backend_disk.h"
@@ -417,13 +418,6 @@ virStorageBackendDiskBuildPool(virConnectPtr conn,
return 0;
}
-
-static int
-virStorageBackendDiskDeleteVol(virConnectPtr conn,
- virStoragePoolObjPtr pool,
- virStorageVolDefPtr vol,
- unsigned int flags);
-
static int
virStorageBackendDiskCreateVol(virConnectPtr conn,
virStoragePoolObjPtr pool,
@@ -487,14 +481,56 @@ virStorageBackendDiskCreateVol(virConnectPtr conn,
static int
virStorageBackendDiskDeleteVol(virConnectPtr conn,
- virStoragePoolObjPtr pool ATTRIBUTE_UNUSED,
- virStorageVolDefPtr vol ATTRIBUTE_UNUSED,
+ virStoragePoolObjPtr pool,
+ virStorageVolDefPtr vol,
unsigned int flags ATTRIBUTE_UNUSED)
{
- /* delete a partition */
- virStorageReportError(conn, VIR_ERR_NO_SUPPORT,
- _("Disk pools are not yet supported"));
- return -1;
+ char *part_num = NULL;
+ int i, n;
+ char devname[PATH_MAX];
+
+ if ((n = readlink(vol->target.path, devname, sizeof(devname))) < 0 &&
+ errno != EINVAL) {
+ virStorageReportError(conn, VIR_ERR_INTERNAL_ERROR,
+ _("Couldn't read volume target path '%s'. %s"),
+ vol->target.path, strerror(errno));
+ return -1;
+ } else if (n <= 0) {
+ strncpy(devname, vol->target.path, PATH_MAX);
+ } else {
+ devname[n] = '\0';
+ }
+
+ if (!STRPREFIX(devname, pool->def->source.devices[0].path)) {
+ virStorageReportError(conn, VIR_ERR_INTERNAL_ERROR,
+ _("Volume path did not start with parent pool "
+ "path."));
+ return -1;
+ }
+
+ part_num = devname + strlen(pool->def->source.devices[0].path);
+
+ if (!part_num) {
+ virStorageReportError(conn, VIR_ERR_INTERNAL_ERROR,
+ _("cannot parse partition number from target "
+ "path '%s'"), vol->target.path);
+ return -1;
+ }
+
+ /* eg parted /dev/sda rm 2 */
+ const char *prog[] = {
+ PARTED,
+ pool->def->source.devices[0].path,
+ "rm",
+ "--script",
+ part_num,
+ NULL,
+ };
+
+ if (virRun(conn, prog, NULL) < 0)
+ return -1;
+
+ return 0;
}
--
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