virsh: support block device storage type in virshParseSnapshotDiskspec

virsh snapshot-create-as supports 'file' storage type in --diskspec by default.
But it doesn't support 'block' storage type in the virshParseSnapshotDiskspec().
So if a snapshot on a block device (e.g. LV) was created, the type of
current running storage source in dumpxml is inconsistent with the actual
backend storage source. It will check file-system type mismatch failed
and return an error message of 'Migration without shared storage is unsafe'
when VM performs a live migration after this snapshot.

Considering virsh has to be able to work remotely that recognizing a block device
by prefix /dev/ or by stat() may be not suitable, so adding a "stype" field
for the --diskspec string which will be either "file" or "block".
e.g. --diskspec vda,snapshot=external,driver=qcow2,stype=block,file=/dev/xxx.

Signed-off-by: Liu Dayu <liu.dayu@zte.com.cn>
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
This commit is contained in:
Liu Dayu 2019-07-08 17:46:34 +08:00 committed by Peter Krempa
parent dd94cc2e71
commit 7ca81e6f19
2 changed files with 28 additions and 8 deletions

View File

@ -251,10 +251,12 @@ virshParseSnapshotDiskspec(vshControl *ctl, virBufferPtr buf, const char *str)
const char *name = NULL;
const char *snapshot = NULL;
const char *driver = NULL;
const char *stype = NULL;
const char *file = NULL;
char **array = NULL;
int narray;
size_t i;
bool isFile = true;
narray = vshStringToArray(str, &array);
if (narray <= 0)
@ -266,6 +268,8 @@ virshParseSnapshotDiskspec(vshControl *ctl, virBufferPtr buf, const char *str)
snapshot = array[i] + strlen("snapshot=");
else if (!driver && STRPREFIX(array[i], "driver="))
driver = array[i] + strlen("driver=");
else if (!stype && STRPREFIX(array[i], "stype="))
stype = array[i] + strlen("stype=");
else if (!file && STRPREFIX(array[i], "file="))
file = array[i] + strlen("file=");
else
@ -275,13 +279,26 @@ virshParseSnapshotDiskspec(vshControl *ctl, virBufferPtr buf, const char *str)
virBufferEscapeString(buf, "<disk name='%s'", name);
if (snapshot)
virBufferAsprintf(buf, " snapshot='%s'", snapshot);
if (stype) {
if (STREQ(stype, "block")) {
isFile = false;
} else if (STRNEQ(stype, "file")) {
vshError(ctl, _("Unknown storage type: '%s'"), stype);
goto cleanup;
}
virBufferAsprintf(buf, " type='%s'", stype);
}
if (driver || file) {
virBufferAddLit(buf, ">\n");
virBufferAdjustIndent(buf, 2);
if (driver)
virBufferAsprintf(buf, "<driver type='%s'/>\n", driver);
if (file)
virBufferEscapeString(buf, "<source file='%s'/>\n", file);
if (file) {
if (isFile)
virBufferEscapeString(buf, "<source file='%s'/>\n", file);
else
virBufferEscapeString(buf, "<source dev='%s'/>\n", file);
}
virBufferAdjustIndent(buf, -2);
virBufferAddLit(buf, "</disk>\n");
} else {
@ -351,7 +368,7 @@ static const vshCmdOptDef opts_snapshot_create_as[] = {
},
{.name = "diskspec",
.type = VSH_OT_ARGV,
.help = N_("disk attributes: disk[,snapshot=type][,driver=type][,file=name]")
.help = N_("disk attributes: disk[,snapshot=type][,driver=type][,stype=type][,file=name]")
},
{.name = NULL}
};

View File

@ -4676,11 +4676,14 @@ The I<--diskspec> option can be used to control how I<--disk-only> and
external full system snapshots create external files. This option can occur
multiple times, according to the number of <disk> elements in the domain
xml. Each <diskspec> is in the
form B<disk[,snapshot=type][,driver=type][,file=name]>. A I<diskspec>
must be provided for disks backed by block devices as libvirt doesn't
auto-generate file names for those. To include a
literal comma in B<disk> or in B<file=name>, escape it with a second
comma. A literal I<--diskspec> must precede each B<diskspec> unless
form B<disk[,snapshot=type][,driver=type][,stype=type][,file=name]>.
A I<diskspec> must be provided for disks backed by block devices as libvirt
doesn't auto-generate file names for those. The optional B<stype> parameter
allows to control the type of the source file. Supported values are 'file'
(default) and 'block'.
To include a literal comma in B<disk> or in B<file=name>, escape it with a
second comma. A literal I<--diskspec> must precede each B<diskspec> unless
all three of I<domain>, I<name>, and I<description> are also present.
For example, a diskspec of "vda,snapshot=external,file=/path/to,,new"
results in the following XML: