[libvirt] [PATCHv3.5 40/43] snapshot: wire up disk-only flag to snapshot-create
Eric Blake
eblake at redhat.com
Thu Sep 1 19:08:04 UTC 2011
Expose the disk-only flag through virsh. Additionally, make
virsh snapshot-create-as take an arbitrary number of diskspecs,
which can be used to build up the xml for <domainsnapshot>.
* tools/virsh.c (cmdSnapshotCreate): Add --disk-only.
(cmdSnapshotCreateAs): Likewise, and add argv diskspec.
(vshParseSnapshotDiskspec): New helper function.
(vshCmddefGetOption): Allow naming of argv field.
* tools/virsh.pod (snapshot-create, snapshot-create-as): Document
them.
* tests/virsh-optparse: Test snapshot-create-as parsing.
---
I went ahead and implemented a decent solution to the snapshot-create-as
needing to provide multiple disk specs when generating xml.
tests/virsh-optparse | 20 +++++++++++
tools/virsh.c | 88 +++++++++++++++++++++++++++++++++++++++++++------
tools/virsh.pod | 28 ++++++++++++++--
3 files changed, 122 insertions(+), 14 deletions(-)
diff --git a/tests/virsh-optparse b/tests/virsh-optparse
index 7b3a25d..cd5e3eb 100755
--- a/tests/virsh-optparse
+++ b/tests/virsh-optparse
@@ -67,6 +67,26 @@ for args in \
virsh -d0 -c $test_url setvcpus $args >out 2>>err || fail=1
LC_ALL=C sort out | compare - exp-out || fail=1
done
+
+# Another complex parsing example
+cat <<\EOF > exp-out || framework_failure
+<domainsnapshot>
+ <description>1<2</description>
+ <disks>
+ <disk name='vda' snapshot='external'>
+ <source file='a&b,c'/>
+ </disk>
+ <disk name='vdb'/>
+ </disks>
+</domainsnapshot>
+
+
+EOF
+virsh -c $test_url snapshot-create-as --print-xml test \
+ --diskspec 'vda,file=a&b,,c,snapshot=external' --description '1<2' \
+ --diskspec vdb >out 2>>err || fail=1
+compare out exp-out || fail=1
+
test -s err && fail=1
(exit $fail); exit $fail
diff --git a/tools/virsh.c b/tools/virsh.c
index 648e62c..c430cfb 100644
--- a/tools/virsh.c
+++ b/tools/virsh.c
@@ -12153,6 +12153,7 @@ static const vshCmdOptDef opts_snapshot_create[] = {
{"current", VSH_OT_BOOL, 0, N_("with redefine, set current snapshot")},
{"no-metadata", VSH_OT_BOOL, 0, N_("take snapshot but create no metadata")},
{"halt", VSH_OT_BOOL, 0, N_("halt domain after snapshot is created")},
+ {"disk-only", VSH_OT_BOOL, 0, N_("capture disk state but not vm state")},
{NULL, 0, 0, NULL}
};
@@ -12173,6 +12174,8 @@ cmdSnapshotCreate(vshControl *ctl, const vshCmd *cmd)
flags |= VIR_DOMAIN_SNAPSHOT_CREATE_NO_METADATA;
if (vshCommandOptBool(cmd, "halt"))
flags |= VIR_DOMAIN_SNAPSHOT_CREATE_HALT;
+ if (vshCommandOptBool(cmd, "disk-only"))
+ flags |= VIR_DOMAIN_SNAPSHOT_CREATE_DISK_ONLY;
if (!vshConnectionUsability(ctl, ctl->conn))
goto cleanup;
@@ -12211,6 +12214,62 @@ cleanup:
/*
* "snapshot-create-as" command
*/
+static int
+vshParseSnapshotDiskspec(vshControl *ctl, virBufferPtr buf, const char *str)
+{
+ int ret = -1;
+ char *name = NULL;
+ char *snapshot = NULL;
+ char *driver = NULL;
+ char *file = NULL;
+ char *spec = vshStrdup(ctl, str);
+ char *tmp = spec;
+ size_t len = strlen(str);
+
+ if (*str == ',')
+ goto cleanup;
+ name = tmp;
+ while ((tmp = strchr(tmp, ','))) {
+ if (tmp[1] == ',') {
+ /* Recognize ,, as an escape for a literal comma */
+ memmove(&tmp[1], &tmp[2], len - (tmp - spec) + 2);
+ len--;
+ tmp++;
+ continue;
+ }
+ /* Terminate previous string, look for next recognized one */
+ *tmp++ = '\0';
+ if (!snapshot && STRPREFIX(tmp, "snapshot="))
+ snapshot = tmp + strlen("snapshot=");
+ else if (!driver && STRPREFIX(tmp, "driver="))
+ driver = tmp + strlen("driver=");
+ else if (!file && STRPREFIX(tmp, "file="))
+ file = tmp + strlen("file=");
+ else
+ goto cleanup;
+ }
+
+ virBufferEscapeString(buf, " <disk name='%s'", name);
+ if (snapshot)
+ virBufferAsprintf(buf, " snapshot='%s'", snapshot);
+ if (driver || file) {
+ virBufferAddLit(buf, ">\n");
+ if (driver)
+ virBufferAsprintf(buf, " <driver type='%s'/>\n", driver);
+ if (file)
+ virBufferEscapeString(buf, " <source file='%s'/>\n", file);
+ virBufferAddLit(buf, " </disk>\n");
+ } else {
+ virBufferAddLit(buf, "/>\n");
+ }
+ ret = 0;
+cleanup:
+ if (ret < 0)
+ vshError(ctl, _("unable to parse diskspec: %s"), str);
+ VIR_FREE(spec);
+ return ret;
+}
+
static const vshCmdInfo info_snapshot_create_as[] = {
{"help", N_("Create a snapshot from a set of args")},
{"desc", N_("Create a snapshot (disk and RAM) from arguments")},
@@ -12224,6 +12283,9 @@ static const vshCmdOptDef opts_snapshot_create_as[] = {
{"print-xml", VSH_OT_BOOL, 0, N_("print XML document rather than create")},
{"no-metadata", VSH_OT_BOOL, 0, N_("take snapshot but create no metadata")},
{"halt", VSH_OT_BOOL, 0, N_("halt domain after snapshot is created")},
+ {"disk-only", VSH_OT_BOOL, 0, N_("capture disk state but not vm state")},
+ {"diskspec", VSH_OT_ARGV, 0,
+ N_("disk attributes: disk[,snapshot=type][,driver=type][,file=name]")},
{NULL, 0, 0, NULL}
};
@@ -12237,11 +12299,14 @@ cmdSnapshotCreateAs(vshControl *ctl, const vshCmd *cmd)
const char *desc = NULL;
virBuffer buf = VIR_BUFFER_INITIALIZER;
unsigned int flags = 0;
+ const vshCmdOpt *opt = NULL;
if (vshCommandOptBool(cmd, "no-metadata"))
flags |= VIR_DOMAIN_SNAPSHOT_CREATE_NO_METADATA;
if (vshCommandOptBool(cmd, "halt"))
flags |= VIR_DOMAIN_SNAPSHOT_CREATE_HALT;
+ if (vshCommandOptBool(cmd, "disk-only"))
+ flags |= VIR_DOMAIN_SNAPSHOT_CREATE_DISK_ONLY;
if (!vshConnectionUsability(ctl, ctl->conn))
goto cleanup;
@@ -12261,6 +12326,16 @@ cmdSnapshotCreateAs(vshControl *ctl, const vshCmd *cmd)
virBufferEscapeString(&buf, " <name>%s</name>\n", name);
if (desc)
virBufferEscapeString(&buf, " <description>%s</description>\n", desc);
+ if (vshCommandOptBool(cmd, "diskspec")) {
+ virBufferAddLit(&buf, " <disks>\n");
+ while ((opt = vshCommandOptArgv(cmd, opt))) {
+ if (vshParseSnapshotDiskspec(ctl, &buf, opt->data) < 0) {
+ virBufferFreeAndReset(&buf);
+ goto cleanup;
+ }
+ }
+ virBufferAddLit(&buf, " </disks>\n");
+ }
virBufferAddLit(&buf, "</domainsnapshot>\n");
buffer = virBufferContentAndReset(&buf);
@@ -12270,11 +12345,6 @@ cmdSnapshotCreateAs(vshControl *ctl, const vshCmd *cmd)
}
if (vshCommandOptBool(cmd, "print-xml")) {
- if (vshCommandOptBool(cmd, "halt")) {
- vshError(ctl, "%s",
- _("--print-xml and --halt are mutually exclusive"));
- goto cleanup;
- }
vshPrint(ctl, "%s\n", buffer);
ret = true;
goto cleanup;
@@ -13327,12 +13397,8 @@ vshCmddefGetOption(vshControl *ctl, const vshCmdDef *cmd, const char *name,
vshError(ctl, _("option --%s already seen"), name);
return NULL;
}
- if (opt->type == VSH_OT_ARGV) {
- vshError(ctl, _("variable argument <%s> "
- "should not be used with --<%s>"), name, name);
- return NULL;
- }
- *opts_seen |= 1 << i;
+ if (opt->type != VSH_OT_ARGV)
+ *opts_seen |= 1 << i;
return opt;
}
}
diff --git a/tools/virsh.pod b/tools/virsh.pod
index 0d1ddd1..e0b9bef 100644
--- a/tools/virsh.pod
+++ b/tools/virsh.pod
@@ -1706,11 +1706,12 @@ used to represent properties of snapshots.
=over 4
=item B<snapshot-create> I<domain> [I<xmlfile>] {[I<--redefine> [I<--current>]]
-| [I<--no-metadata>] [I<--halt>]}
+| [I<--no-metadata>] [I<--halt>] [I<--disk-only>]}
Create a snapshot for domain I<domain> with the properties specified in
I<xmlfile>. Normally, the only properties settable for a domain snapshot
-are the <name> and <description> elements; the rest of the fields are
+are the <name> and <description> elements, as well as <disks> if
+I<--disk-only> is given; the rest of the fields are
ignored, and automatically filled in by libvirt. If I<xmlfile> is
completely omitted, then libvirt will choose a value for all fields.
The new snapshot will become current, as listed by B<snapshot-current>.
@@ -1718,6 +1719,14 @@ The new snapshot will become current, as listed by B<snapshot-current>.
If I<--halt> is specified, the domain will be left in an inactive state
after the snapshot is created.
+If I<--disk-only> is specified, the snapshot will only include disk
+state rather than the usual system checkpoint with vm state. Disk
+snapshots are faster than full system checkpoints, but reverting to a
+disk snapshot may require fsck or journal replays, since it is like
+the disk state at the point when the power cord is abruptly pulled;
+and mixing I<--halt> and I<--disk-only> loses any data that was not
+flushed to disk at the time.
+
If I<--redefine> is specified, then all XML elements produced by
B<snapshot-dumpxml> are valid; this can be used to migrate snapshot
hierarchy from one machine to another, to recreate hierarchy for the
@@ -1741,13 +1750,26 @@ by command such as B<destroy> or by internal guest action).
=item B<snapshot-create-as> I<domain> {[I<--print-xml>]
| [I<--no-metadata>] [I<--halt>]} [I<name>] [I<description>]
+[I<--disk-only> [I<diskspec>]...]
Create a snapshot for domain I<domain> with the given <name> and
<description>; if either value is omitted, libvirt will choose a
value. If I<--print-xml> is specified, then XML appropriate for
I<snapshot-create> is output, rather than actually creating a snapshot.
Otherwise, if I<--halt> is specified, the domain will be left in an
-inactive state after the snapshot is created.
+inactive state after the snapshot is created, and if I<--disk-only>
+is specified, the snapshot will not include vm state.
+
+The I<--disk-only> flag is used to request a disk-only snapshot. When
+this flag is in use, the command can also take additional I<diskspec>
+arguments to add <disk> elements to the xml. Each <diskspec> is in the
+form B<disk[,snapshot=type][,driver=type][,file=name]>. To include a
+literal comma in B<disk> or in B<file=name>, escape it with a second
+comma. For example, a diskspec of "vda,snapshot=external,file=/path/to,,new"
+results in the following XML:
+ <disk name='vda' snapshot='external'>
+ <source file='/path/to,new'/>
+ </disk>
If I<--no-metadata> is specified, then the snapshot data is created,
but any metadata is immediately discarded (that is, libvirt does not
--
1.7.4.4
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