[Libguestfs] [PATCH v2] libvirt: read disk paths from pools (RHBZ#1366049)
Pino Toscano
ptoscano at redhat.com
Thu Sep 22 15:40:25 UTC 2016
A disk of type 'volume' is stored as
<source pool='pool_name' volume='volume_name'/>
and its real location is inside the 'volume_name', as 'pool_name': in
this case, query libvirt for the actual path of the specified volume in
the specified pool.
Adjust the code so that:
- for_each_disk gets the virConnectPtr, needed to do operations with
libvirt
- when extracting the disk filename depending on the type, the code
snippet doing it can directly set 'filename', without setting an XPath
result variable
Only file-based volumes are supported for now; more types can be added
(with proper testing) later on.
---
src/libvirt-domain.c | 134 +++++++++++++++++++++++++----
tests/disks/test-qemu-drive-libvirt.sh | 16 ++++
tests/disks/test-qemu-drive-libvirt.xml.in | 37 ++++++++
3 files changed, 172 insertions(+), 15 deletions(-)
diff --git a/src/libvirt-domain.c b/src/libvirt-domain.c
index d54814f..4d4142d 100644
--- a/src/libvirt-domain.c
+++ b/src/libvirt-domain.c
@@ -40,8 +40,9 @@
#if defined(HAVE_LIBVIRT)
static xmlDocPtr get_domain_xml (guestfs_h *g, virDomainPtr dom);
-static ssize_t for_each_disk (guestfs_h *g, xmlDocPtr doc, int (*f) (guestfs_h *g, const char *filename, const char *format, int readonly, const char *protocol, char *const *server, const char *username, void *data), void *data);
+static ssize_t for_each_disk (guestfs_h *g, virConnectPtr conn, xmlDocPtr doc, int (*f) (guestfs_h *g, const char *filename, const char *format, int readonly, const char *protocol, char *const *server, const char *username, void *data), void *data);
static int libvirt_selinux_label (guestfs_h *g, xmlDocPtr doc, char **label_rtn, char **imagelabel_rtn);
+static char *filename_from_pool (guestfs_h *g, virConnectPtr conn, const char *pool_nane, const char *volume_name);
static void
ignore_errors (void *ignore, virErrorPtr ignore2)
@@ -311,7 +312,7 @@ guestfs_impl_add_libvirt_dom (guestfs_h *g, void *domvp,
* all disks are added or none are added.
*/
ckp = guestfs_int_checkpoint_drives (g);
- r = for_each_disk (g, doc, add_disk, &data);
+ r = for_each_disk (g, virDomainGetConnect (dom), doc, add_disk, &data);
if (r == -1)
guestfs_int_rollback_drives (g, ckp);
@@ -466,6 +467,7 @@ libvirt_selinux_label (guestfs_h *g, xmlDocPtr doc,
*/
static ssize_t
for_each_disk (guestfs_h *g,
+ virConnectPtr conn,
xmlDocPtr doc,
int (*f) (guestfs_h *g,
const char *filename, const char *format,
@@ -509,6 +511,8 @@ for_each_disk (guestfs_h *g,
CLEANUP_XMLXPATHFREEOBJECT xmlXPathObjectPtr xpprotocol = NULL;
CLEANUP_XMLXPATHFREEOBJECT xmlXPathObjectPtr xphost = NULL;
CLEANUP_XMLXPATHFREEOBJECT xmlXPathObjectPtr xpusername = NULL;
+ CLEANUP_XMLXPATHFREEOBJECT xmlXPathObjectPtr xppool = NULL;
+ CLEANUP_XMLXPATHFREEOBJECT xmlXPathObjectPtr xpvolume = NULL;
xmlAttrPtr attr;
int readonly;
int t;
@@ -628,22 +632,66 @@ for_each_disk (guestfs_h *g,
* TODO: secrets: ./auth/secret/@type,
* ./auth/secret/@usage || ./auth/secret/@uuid
*/
- } else
- continue; /* type <> "file", "block", or "network", skip it */
+ } else if (STREQ (type, "volume")) { /* type = "volume", use source/@volume */
+ CLEANUP_FREE char *pool = NULL;
+ CLEANUP_FREE char *volume = NULL;
+
+ xpathCtx->node = nodes->nodeTab[i];
- assert (xpfilename);
- assert (xpfilename->nodesetval);
- if (xpfilename->nodesetval->nodeNr > 0) {
- assert (xpfilename->nodesetval->nodeTab[0]);
- assert (xpfilename->nodesetval->nodeTab[0]->type ==
+ /* Get the source pool. Required. */
+ xppool = xmlXPathEvalExpression (BAD_CAST "./source/@pool",
+ xpathCtx);
+ if (xppool == NULL ||
+ xppool->nodesetval == NULL ||
+ xppool->nodesetval->nodeNr == 0)
+ continue;
+ assert (xppool->nodesetval->nodeTab[0]);
+ assert (xppool->nodesetval->nodeTab[0]->type ==
+ XML_ATTRIBUTE_NODE);
+ attr = (xmlAttrPtr) xppool->nodesetval->nodeTab[0];
+ pool = (char *) xmlNodeListGetString (doc, attr->children, 1);
+
+ /* Get the source volume. Required. */
+ xpvolume = xmlXPathEvalExpression (BAD_CAST "./source/@volume",
+ xpathCtx);
+ if (xpvolume == NULL ||
+ xpvolume->nodesetval == NULL ||
+ xpvolume->nodesetval->nodeNr == 0)
+ continue;
+ assert (xpvolume->nodesetval->nodeTab[0]);
+ assert (xpvolume->nodesetval->nodeTab[0]->type ==
XML_ATTRIBUTE_NODE);
- attr = (xmlAttrPtr) xpfilename->nodesetval->nodeTab[0];
- filename = (char *) xmlNodeListGetString (doc, attr->children, 1);
- debug (g, "disk[%zu]: filename: %s", i, filename);
+ attr = (xmlAttrPtr) xpvolume->nodesetval->nodeTab[0];
+ volume = (char *) xmlNodeListGetString (doc, attr->children, 1);
+
+ debug (g, "disk[%zu]: pool: %s; volume: %s", i, pool, volume);
+
+ filename = filename_from_pool (g, conn, pool, volume);
+ if (filename == NULL)
+ continue; /* filename_from_pool already called error() */
+ } else
+ continue; /* type is not handled above, skip it */
+
+ /* Allow any of the code blocks above (handling a disk type)
+ * to directly get the filename (setting 'filename'), with no need
+ * for an XPath evaluation.
+ */
+ if (filename == NULL) {
+ assert (xpfilename);
+ assert (xpfilename->nodesetval);
+ if (xpfilename->nodesetval->nodeNr > 0) {
+ assert (xpfilename->nodesetval->nodeTab[0]);
+ assert (xpfilename->nodesetval->nodeTab[0]->type ==
+ XML_ATTRIBUTE_NODE);
+ attr = (xmlAttrPtr) xpfilename->nodesetval->nodeTab[0];
+ filename = (char *) xmlNodeListGetString (doc, attr->children, 1);
+ }
+ else
+ /* For network protocols (eg. nbd), name may be omitted. */
+ filename = safe_strdup (g, "");
}
- else
- /* For network protocols (eg. nbd), name may be omitted. */
- filename = safe_strdup (g, "");
+
+ debug (g, "disk[%zu]: filename: %s", i, filename);
/* Get the disk format (may not be set). */
xpathCtx->node = nodes->nodeTab[i];
@@ -784,6 +832,62 @@ get_domain_xml (guestfs_h *g, virDomainPtr dom)
return doc;
}
+static char *
+filename_from_pool (guestfs_h *g, virConnectPtr conn,
+ const char *pool_name, const char *volume_name)
+{
+ char *filename = NULL;
+ virErrorPtr err;
+ virStoragePoolPtr pool = NULL;
+ virStorageVolPtr vol = NULL;
+ virStorageVolInfo info;
+ int ret;
+
+ pool = virStoragePoolLookupByName (conn, pool_name);
+ if (pool == NULL) {
+ err = virGetLastError ();
+ error (g, _("no libvirt pool called '%s': %s"),
+ pool_name, err->message);
+ goto cleanup;
+ }
+
+ vol = virStorageVolLookupByName (pool, volume_name);
+ if (vol == NULL) {
+ err = virGetLastError ();
+ error (g, _("no volume called '%s' in the libvirt pool '%s': %s"),
+ volume_name, pool_name, err->message);
+ goto cleanup;
+ }
+
+ ret = virStorageVolGetInfo (vol, &info);
+ if (ret < 0) {
+ err = virGetLastError ();
+ error (g, _("cannot get information of the libvirt volume '%s': %s"),
+ volume_name, err->message);
+ goto cleanup;
+ }
+
+ debug (g, "type of libvirt volume %s: %d", volume_name, info.type);
+
+ /* Support only file-based volumes for now. */
+ if (info.type != VIR_STORAGE_VOL_FILE)
+ goto cleanup;
+
+ filename = virStorageVolGetPath (vol);
+ if (filename == NULL) {
+ err = virGetLastError ();
+ error (g, _("cannot get the filename of the libvirt volume '%s': %s"),
+ volume_name, err->message);
+ goto cleanup;
+ }
+
+ cleanup:
+ if (vol) virStorageVolFree (vol);
+ if (pool) virStoragePoolFree (pool);
+
+ return filename;
+}
+
#else /* no libvirt at compile time */
#define NOT_IMPL(r) \
diff --git a/tests/disks/test-qemu-drive-libvirt.sh b/tests/disks/test-qemu-drive-libvirt.sh
index 215a99e..b2656ba 100755
--- a/tests/disks/test-qemu-drive-libvirt.sh
+++ b/tests/disks/test-qemu-drive-libvirt.sh
@@ -47,6 +47,12 @@ export LIBGUESTFS_BACKEND=direct
export LIBGUESTFS_HV="${abs_srcdir}/debug-qemu.sh"
export DEBUG_QEMU_FILE="${abs_builddir}/test-qemu-drive-libvirt.out"
+# Setup the fake pool.
+pool_dir=tmp
+rm -rf "$pool_dir"
+mkdir "$pool_dir"
+touch "$pool_dir/in-pool"
+
function check_output ()
{
if [ ! -f "$DEBUG_QEMU_FILE" ]; then
@@ -104,8 +110,18 @@ check_output
grep -sq -- '-drive file=sheepdog:volume,' "$DEBUG_QEMU_FILE" || fail
rm "$DEBUG_QEMU_FILE"
+# Local, stored in a pool.
+
+$guestfish -d pool1 run ||:
+check_output
+grep -sq -- "-drive file=$abs_builddir/tmp/in-pool" "$DEBUG_QEMU_FILE" || fail
+rm "$DEBUG_QEMU_FILE"
+
# To do:
# HTTP - curl not yet supported by libvirt
# SSH.
+
+# Clean up.
+rm -r "$pool_dir"
diff --git a/tests/disks/test-qemu-drive-libvirt.xml.in b/tests/disks/test-qemu-drive-libvirt.xml.in
index e8e6252..f0b7fe0 100644
--- a/tests/disks/test-qemu-drive-libvirt.xml.in
+++ b/tests/disks/test-qemu-drive-libvirt.xml.in
@@ -132,4 +132,41 @@
</devices>
</domain>
+ <domain type='test' xmlns:test='http://libvirt.org/schemas/domain/test/1.0'>
+ <test:runstate>5</test:runstate> <!-- 5 == VIR_DOMAIN_SHUTOFF -->
+ <name>pool1</name>
+ <memory>1048576</memory>
+ <os>
+ <type>hvm</type>
+ <boot dev='hd'/>
+ </os>
+ <devices>
+ <disk type='volume' device='disk'>
+ <driver name='qemu'/>
+ <source pool='pool1' volume='in-pool'/>
+ <target dev='vda' bus='virtio'/>
+ </disk>
+ </devices>
+ </domain>
+
+ <pool type='dir'>
+ <name>pool1</name>
+ <uuid>12345678-1234-1234-1234-1234567890ab</uuid>
+ <target>
+ <path>@abs_builddir@/tmp</path>
+ </target>
+
+ <volume type='file'>
+ <name>in-pool</name>
+ <capacity unit='bytes'>1048576</capacity>
+ <key>@abs_builddir@/tmp/in-pool</key>
+ <source>
+ </source>
+ <target>
+ <path>@abs_builddir@/tmp/in-pool</path>
+ </target>
+ </volume>
+
+ </pool>
+
</node>
--
2.7.4
More information about the Libguestfs
mailing list