[Libvir] [PATCH] Allow virDomainDefine to overwrite existing inactive domains for xen 3.0.3 userspace installations
12:30 p.m.
virDomainDefineXML should overwrite an existing inactive domain config
if it finds one; it does this successfully for later (post 3.0.3) xen
versions. However on xen 3.0.3 overwriting an existing config would fail
with a name conflict. This patch allows the overwrite, removing the
prior config from the config hashes.
If someone more familiar than I with libvirt error handling and style
could look at this and tell me if I've done something horribly wrong,
I'd appreciate it.
Signed-off-by: Hugh Brock <hbrock(a)redhat.com>
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Hugh Brock | virt-manager http://virt-manager.org
hbrock(a)redhat.com | virtualization library http://libvirt.org
5:26 a.m.
Hugh Brock wrote:
virDomainDefineXML should overwrite an existing inactive domain
config
if it finds one; it does this successfully for later (post 3.0.3) xen
versions. However on xen 3.0.3 overwriting an existing config would fail
with a name conflict. This patch allows the overwrite, removing the
prior config from the config hashes.
If someone more familiar than I with libvirt error handling and style
could look at this and tell me if I've done something horribly wrong,
I'd appreciate it.
Signed-off-by: Hugh Brock <hbrock(a)redhat.com>
Thinking aloud and trying to untangle the various hashes used ...
Index: src/xm_internal.c
===================================================================
RCS file: /data/cvs/libvirt/src/xm_internal.c,v
retrieving revision 1.23
diff -u -r1.23 xm_internal.c
--- src/xm_internal.c 4 Apr 2007 14:19:49 -0000 1.23
+++ src/xm_internal.c 1 May 2007 17:23:05 -0000
@@ -2072,7 +2072,9 @@
*/
virDomainPtr xenXMDomainDefineXML(virConnectPtr conn, const char *xml) {
virDomainPtr ret;
+ virDomainPtr olddomain;
char filename[PATH_MAX];
+ const char * oldfilename;
unsigned char uuid[VIR_UUID_BUFLEN];
virConfPtr conf = NULL;
xenXMConfCachePtr entry = NULL;
@@ -2103,8 +2105,44 @@
}
if (virHashLookup(nameConfigMap, value->str)) {
- xenXMError(conn, VIR_ERR_INTERNAL_ERROR, "domain with name already
exists");
- goto error;
+ /* domain exists, we will overwrite it */
+
+ if (!(oldfilename = (char *)virHashLookup(nameConfigMap, value->str))) {
+ xenXMError(conn, VIR_ERR_INTERNAL_ERROR, "can't retrieve config
filename for domain to overwrite");
+ goto error;
+ }
So get the filename from the nameConfigMap. Looks OK, although you
could have also got the filename from configDir ++ "/" ++ value->str,
but no matter.
+ if (!(entry = virHashLookup(configCache, oldfilename))) {
+ xenXMError(conn, VIR_ERR_INTERNAL_ERROR, "can't retrieve config
entry for domain to overwrite");
+ goto error;
+ }
Get the xenXMConfCache object from the configCache keyed on filename.
Looks OK.
Despite the name, configCache isn't literally a cache. Rather it's a
list of filename -> config entries for everything under /etc/xen.
+ if (xenXMConfigGetUUID(entry->conf, "uuid",
uuid) < 0) {
+ xenXMError(conn, VIR_ERR_INTERNAL_ERROR, "uuid config parameter is
missing");
+ goto error;
+ }
Get the UUID from the config file.
+ if (!(olddomain = virGetDomain(conn, value->str, uuid)))
+ goto error;
Get the old domain, given name & UUID.
+ if (olddomain->id != -1) {
+ xenXMError(conn, VIR_ERR_INTERNAL_ERROR, "can't overwrite an active
domain");
+ goto error;
+ }
+
+ /* Remove the name -> filename mapping */
+ if (virHashRemoveEntry(nameConfigMap, value->str, NULL) < 0) {
+ xenXMError(conn, VIR_ERR_INTERNAL_ERROR, "failed to remove old domain
from config map");
+ goto error;
+ }
Remove the old mapping in nameConfigMap.
+ /* Remove the config record itself */
+ if (virHashRemoveEntry(configCache, oldfilename, xenXMConfigFree) < 0) {
+ xenXMError(conn, VIR_ERR_INTERNAL_ERROR, "failed to remove old domain
from config map");
+ goto error;
+ }
Remove the configCache entry.
+ entry = NULL;
}
if ((strlen(configDir) + 1 + strlen(value->str) + 1) >
PATH_MAX) {
and then drop through to virConfWriteFile which will blindly overwrite
the file.
Looks A-OK to me!
Rich.
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8:35 a.m.
On Tue, May 01, 2007 at 01:30:23PM -0400, Hugh Brock wrote:
+ if (!(olddomain = virGetDomain(conn, value->str, uuid)))
+ goto error;
+
+ if (olddomain->id != -1) {
+ xenXMError(conn, VIR_ERR_INTERNAL_ERROR, "can't overwrite an active
domain");
+ goto error;
+ }
+
Actually, it is valid to call virDomainDefineXML() even for a domain which
is already running. This is critical to be able to implement provisioning
tools like virt-install - we first boot a domain with the config needed
to kick off the installer (eg explicit initrd/kernel, or ISO), and then
define a config file for subsequent boots (eg pygrub). So, just killing
these 2 lines & the rest of the patch is OK.
Dan.
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2 comments
3 participants
participants (3)
-
Daniel P. Berrange -
Hugh Brock -
Richard W.M. Jones