[libvirt] [PATCH] Support creation of sparse LVM volumes

From: "Daniel P. Berrange" <berrange@redhat.com> When calling 'lvcreate' if specifying both the '-L' and '--virtualsize' options, the latter will be treated as the capacity and the former as the allocation. This can be used to support sparse volume creation. In addition, when listing volumes it is neccessary to include the 'size' field in lvs output, so that we can detect sparse volume allocation correctly. --- src/storage/storage_backend_logical.c | 27 ++++++++++++++++++--------- 1 files changed, 18 insertions(+), 9 deletions(-) diff --git a/src/storage/storage_backend_logical.c b/src/storage/storage_backend_logical.c index 9fe769b..c6e09e6 100644 --- a/src/storage/storage_backend_logical.c +++ b/src/storage/storage_backend_logical.c @@ -171,6 +171,11 @@ virStorageBackendLogicalMakeVol(virStoragePoolObjPtr pool, "%s", _("malformed volume extent size value")); goto cleanup; } + if (virStrToLong_ull(groups[8], NULL, 10, &vol->allocation) < 0) { + virStorageReportError(VIR_ERR_INTERNAL_ERROR, + "%s", _("malformed volume allocation value")); + goto cleanup; + } /* Now parse the "devices" field separately */ regex = strdup(regex_unit); @@ -271,12 +276,12 @@ virStorageBackendLogicalFindLVs(virStoragePoolObjPtr pool, virStorageVolDefPtr vol) { /* - * # lvs --separator , --noheadings --units b --unbuffered --nosuffix --options "lv_name,origin,uuid,devices,seg_size,vg_extent_size" VGNAME - * RootLV,,06UgP5-2rhb-w3Bo-3mdR-WeoL-pytO-SAa2ky,/dev/hda2(0),5234491392,33554432 - * SwapLV,,oHviCK-8Ik0-paqS-V20c-nkhY-Bm1e-zgzU0M,/dev/hda2(156),1040187392,33554432 - * Test2,,3pg3he-mQsA-5Sui-h0i6-HNmc-Cz7W-QSndcR,/dev/hda2(219),1073741824,33554432 - * Test3,,UB5hFw-kmlm-LSoX-EI1t-ioVd-h7GL-M0W8Ht,/dev/hda2(251),2181038080,33554432 - * Test3,Test2,UB5hFw-kmlm-LSoX-EI1t-ioVd-h7GL-M0W8Ht,/dev/hda2(187),1040187392,33554432 + * # lvs --separator , --noheadings --units b --unbuffered --nosuffix --options "lv_name,origin,uuid,devices,seg_size,vg_extent_size,size" VGNAME + * RootLV,,06UgP5-2rhb-w3Bo-3mdR-WeoL-pytO-SAa2ky,/dev/hda2(0),5234491392,33554432,5234491392 + * SwapLV,,oHviCK-8Ik0-paqS-V20c-nkhY-Bm1e-zgzU0M,/dev/hda2(156),1040187392,33554432,1040187392 + * Test2,,3pg3he-mQsA-5Sui-h0i6-HNmc-Cz7W-QSndcR,/dev/hda2(219),1073741824,33554432,1073741824 + * Test3,,UB5hFw-kmlm-LSoX-EI1t-ioVd-h7GL-M0W8Ht,/dev/hda2(251),2181038080,33554432,2181038080 + * Test3,Test2,UB5hFw-kmlm-LSoX-EI1t-ioVd-h7GL-M0W8Ht,/dev/hda2(187),1040187392,33554432,1040187392 * * Pull out name, origin, & uuid, device, device extent start #, segment size, extent size. * @@ -290,10 +295,10 @@ virStorageBackendLogicalFindLVs(virStoragePoolObjPtr pool, * striped, so "," is not a suitable separator either (rhbz 727474). */ const char *regexes[] = { - "^\\s*(\\S+)#(\\S*)#(\\S+)#(\\S+)#(\\S+)#([0-9]+)#(\\S+)#([0-9]+)#?\\s*$" + "^\\s*(\\S+)#(\\S*)#(\\S+)#(\\S+)#(\\S+)#([0-9]+)#(\\S+)#([0-9]+)#([0-9]+)#?\\s*$" }; int vars[] = { - 8 + 9 }; int ret = -1; virCommandPtr cmd; @@ -304,7 +309,7 @@ virStorageBackendLogicalFindLVs(virStoragePoolObjPtr pool, "--units", "b", "--unbuffered", "--nosuffix", - "--options", "lv_name,origin,uuid,devices,segtype,stripes,seg_size,vg_extent_size", + "--options", "lv_name,origin,uuid,devices,segtype,stripes,seg_size,vg_extent_size,size", pool->def->source.name, NULL); if (virStorageBackendRunProgRegex(pool, @@ -718,6 +723,10 @@ virStorageBackendLogicalCreateVol(virConnectPtr conn, "--name", vol->name, NULL); virCommandAddArg(cmd, "-L"); + if (vol->capacity != vol->allocation) { + virCommandAddArgFormat(cmd, "%lluK", VIR_DIV_UP(vol->allocation, 1024)); + virCommandAddArg(cmd, "--virtualsize"); + } virCommandAddArgFormat(cmd, "%lluK", VIR_DIV_UP(vol->capacity, 1024)); if (vol->backingStore.path) virCommandAddArgPair(cmd, "-s", vol->backingStore.path); -- 1.7.7.6

On 07/11/2012 10:30 AM, Daniel P. Berrange wrote:
From: "Daniel P. Berrange" <berrange@redhat.com>
When calling 'lvcreate' if specifying both the '-L' and '--virtualsize' options, the latter will be treated as the capacity and the former as the allocation. This can be used to support sparse volume creation. In addition, when listing volumes it is neccessary to include the 'size'
s/neccessary/necessary/
field in lvs output, so that we can detect sparse volume allocation correctly. --- src/storage/storage_backend_logical.c | 27 ++++++++++++++++++--------- 1 files changed, 18 insertions(+), 9 deletions(-)
ACK. -- Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
participants (2)
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Daniel P. Berrange
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Eric Blake