10:08 p.m.
I got confused when 'virsh domblkinfo dom disk' required the
path to a disk (which can be ambiguous, since a single file
can back multiple disks), rather than the unambiguous target
device name that I was using in disk snapshots. So, in true
developer fashion, I went for the best of both worlds - all
interfaces that operate on a disk (aka block) now accept
either the target name or the unambiguous path to the backing
file used by the disk.
* src/conf/domain_conf.h (virDomainDiskIndexByName): Add
parameter.
(virDomainDiskPathByName): New prototype.
* src/libvirt_private.syms (domain_conf.h): Export it.
* src/conf/domain_conf.c (virDomainDiskIndexByName): Also allow
searching by path, and decide whether ambiguity is okay.
(virDomainDiskPathByName): New function.
(virDomainDiskRemoveByName, virDomainSnapshotAlignDisks): Update
callers.
* src/qemu/qemu_driver.c (qemudDomainBlockPeek)
(qemuDomainAttachDeviceConfig, qemuDomainUpdateDeviceConfig)
(qemuDomainGetBlockInfo, qemuDiskPathToAlias): Likewise.
* src/qemu/qemu_process.c (qemuProcessFindDomainDiskByPath):
Likewise.
* src/libxl/libxl_driver.c (libxlDomainAttachDeviceDiskLive)
(libxlDomainDetachDeviceDiskLive, libxlDomainAttachDeviceConfig)
(libxlDomainUpdateDeviceConfig): Likewise.
* src/uml/uml_driver.c (umlDomainBlockPeek): Likewise.
* src/xen/xend_internal.c (xenDaemonDomainBlockPeek): Likewise.
* docs/formatsnapshot.html.in: Update documentation.
* tools/virsh.pod (domblkstat, domblkinfo): Likewise.
* docs/schemas/domaincommon.rng (diskTarget): Tighten pattern on
disk targets.
* docs/schemas/domainsnapshot.rng (disksnapshot): Update to match.
* tests/domainsnapshotxml2xmlin/disk_snapshot.xml: Update test.
---
docs/formatsnapshot.html.in | 7 +-
docs/schemas/domaincommon.rng | 7 ++-
docs/schemas/domainsnapshot.rng | 5 +-
src/conf/domain_conf.c | 57 ++++++++++---
src/conf/domain_conf.h | 4 +-
src/libvirt_private.syms | 1 +
src/libxl/libxl_driver.c | 11 ++-
src/qemu/qemu_driver.c | 104 ++++++++++------------
src/qemu/qemu_process.c | 11 +--
src/uml/uml_driver.c | 56 ++++++-------
src/xen/xend_internal.c | 12 +--
tests/domainsnapshotxml2xmlin/disk_snapshot.xml | 2 +-
tools/virsh.pod | 8 ++-
13 files changed, 155 insertions(+), 130 deletions(-)
diff --git a/docs/formatsnapshot.html.in b/docs/formatsnapshot.html.in
index 5aebd72..e476c8f 100644
--- a/docs/formatsnapshot.html.in
+++ b/docs/formatsnapshot.html.in
@@ -109,8 +109,9 @@
<dt><code>disk</code></dt>
<dd>This sub-element describes the snapshot properties of a
specific disk. The attribute <code>name</code> is
- mandatory, and must match the <code><target
- dev='name'/></code> of one of
+ mandatory, and must match either the <code><target
+ dev='name'/></code> or an unambiguous
<code><source
+ file='name'/></code> of one of
the <a href="formatdomain.html#elementsDisks">disk
devices</a> specified for the domain at the time of the
snapshot. The attribute <code>snapshot</code> is
@@ -179,7 +180,7 @@
<domainsnapshot>
<description>Snapshot of OS install and
updates</description>
<disks>
- <disk name='vda'>
+ <disk name='/path/to/old'>
<source file='/path/to/new'/>
</disk>
<disk name='vdb' snapshot='no'/>
diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index 0af9e0f..e1c6a95 100644
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -770,10 +770,15 @@
</choice>
</element>
</define>
+ <define name="diskTarget">
+ <data type="string">
+ <param
name="pattern">(ioemu:)?(fd|hd|sd|vd|xvd|ubd)[a-zA-Z0-9_]+</param>
+ </data>
+ </define>
<define name="target">
<element name="target">
<attribute name="dev">
- <ref name="deviceName"/>
+ <ref name="diskTarget"/>
</attribute>
<optional>
<attribute name="bus">
diff --git a/docs/schemas/domainsnapshot.rng b/docs/schemas/domainsnapshot.rng
index 671fbe0..0ef0631 100644
--- a/docs/schemas/domainsnapshot.rng
+++ b/docs/schemas/domainsnapshot.rng
@@ -82,7 +82,10 @@
<define name='disksnapshot'>
<element name='disk'>
<attribute name='name'>
- <ref name='deviceName'/>
+ <choice>
+ <ref name='diskTarget'/>
+ <ref name='absFilePath'/>
+ </choice>
</attribute>
<choice>
<attribute name='snapshot'>
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 043e73f..ec75dbd 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -5516,17 +5516,44 @@ virDomainChrTargetTypeToString(int deviceType,
return type;
}
-int virDomainDiskIndexByName(virDomainDefPtr def, const char *name)
+int
+virDomainDiskIndexByName(virDomainDefPtr def, const char *name,
+ bool allow_ambiguous)
{
virDomainDiskDefPtr vdisk;
int i;
+ int candidate = -1;
+ /* We prefer the <target dev='name'/> name (it's shorter, required
+ * for all disks, and should be unambiguous), but also support
+ * <source file='name'/> (if unambiguous). Assume dst if there is
+ * no leading slash, source name otherwise. */
for (i = 0; i < def->ndisks; i++) {
vdisk = def->disks[i];
- if (STREQ(vdisk->dst, name))
- return i;
+ if (*name != '/') {
+ if (STREQ(vdisk->dst, name))
+ return i;
+ } else if (vdisk->src &&
+ STREQ(vdisk->src, name)) {
+ if (allow_ambiguous)
+ return i;
+ if (candidate >= 0)
+ return -1;
+ candidate = i;
+ }
}
- return -1;
+ return candidate;
+}
+
+/* Return the path to a disk image if a string identifies at least one
+ * disk belonging to the domain (both device strings 'vda' and paths
+ * '/path/to/file' are converted into '/path/to/file'). */
+const char *
+virDomainDiskPathByName(virDomainDefPtr def, const char *name)
+{
+ int i = virDomainDiskIndexByName(def, name, true);
+
+ return i < 0 ? NULL : def->disks[i]->src;
}
int virDomainDiskInsert(virDomainDefPtr def,
@@ -5602,7 +5629,7 @@ void virDomainDiskRemove(virDomainDefPtr def, size_t i)
int virDomainDiskRemoveByName(virDomainDefPtr def, const char *name)
{
- int i = virDomainDiskIndexByName(def, name);
+ int i = virDomainDiskIndexByName(def, name, false);
if (i < 0)
return -1;
virDomainDiskRemove(def, i);
@@ -11205,11 +11232,12 @@ disksorter(const void *a, const void *b)
/* Align def->disks to def->domain. Sort the list of def->disks,
* filling in any missing disks or snapshot state defaults given by
- * the domain, with a fallback to a passed in default. Issue an error
- * and return -1 if any def->disks[n]->name appears more than once or
- * does not map to dom->disks. If require_match, also require that
- * existing def->disks snapshot states do not override explicit
- * def->dom settings. */
+ * the domain, with a fallback to a passed in default. Convert paths
+ * to disk targets for uniformity. Issue an error and return -1 if
+ * any def->disks[n]->name appears more than once or does not map to
+ * dom->disks. If require_match, also require that existing
+ * def->disks snapshot states do not override explicit def->dom
+ * settings. */
int
virDomainSnapshotAlignDisks(virDomainSnapshotDefPtr def,
int default_snapshot,
@@ -11246,7 +11274,7 @@ virDomainSnapshotAlignDisks(virDomainSnapshotDefPtr def,
/* Double check requested disks. */
for (i = 0; i < def->ndisks; i++) {
virDomainSnapshotDiskDefPtr disk = &def->disks[i];
- int idx = virDomainDiskIndexByName(def->dom, disk->name);
+ int idx = virDomainDiskIndexByName(def->dom, disk->name, false);
int disk_snapshot;
if (idx < 0) {
@@ -11284,6 +11312,13 @@ virDomainSnapshotAlignDisks(virDomainSnapshotDefPtr def,
disk->file, disk->name);
goto cleanup;
}
+ if (STRNEQ(disk->file, def->dom->disks[idx]->dst)) {
+ VIR_FREE(disk->file);
+ if (!(disk->file = strdup(def->dom->disks[idx]->dst))) {
+ virReportOOMError();
+ goto cleanup;
+ }
+ }
}
/* Provide defaults for all remaining disks. */
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index d835f96..c240fe3 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -1557,7 +1557,9 @@ int virDomainVcpuPinAdd(virDomainDefPtr def,
int virDomainVcpuPinDel(virDomainDefPtr def, int vcpu);
-int virDomainDiskIndexByName(virDomainDefPtr def, const char *name);
+int virDomainDiskIndexByName(virDomainDefPtr def, const char *name,
+ bool allow_ambiguous);
+const char *virDomainDiskPathByName(virDomainDefPtr, const char *name);
int virDomainDiskInsert(virDomainDefPtr def,
virDomainDiskDefPtr disk);
void virDomainDiskInsertPreAlloced(virDomainDefPtr def,
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index a953326..5e8f30c 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -284,6 +284,7 @@ virDomainDiskInsert;
virDomainDiskInsertPreAlloced;
virDomainDiskIoTypeFromString;
virDomainDiskIoTypeToString;
+virDomainDiskPathByName;
virDomainDiskRemove;
virDomainDiskRemoveByName;
virDomainDiskSnapshotTypeFromString;
diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c
index d6e0c28..fe141bc 100644
--- a/src/libxl/libxl_driver.c
+++ b/src/libxl/libxl_driver.c
@@ -2929,7 +2929,7 @@ libxlDomainAttachDeviceDiskLive(libxlDomainObjPrivatePtr priv,
break;
case VIR_DOMAIN_DISK_DEVICE_DISK:
if (l_disk->bus == VIR_DOMAIN_DISK_BUS_XEN) {
- if (virDomainDiskIndexByName(vm->def, l_disk->dst) >= 0) {
+ if (virDomainDiskIndexByName(vm->def, l_disk->dst, true) >= 0)
{
libxlError(VIR_ERR_OPERATION_FAILED,
_("target %s already exists"), l_disk->dst);
goto cleanup;
@@ -2991,7 +2991,8 @@ libxlDomainDetachDeviceDiskLive(libxlDomainObjPrivatePtr priv,
if (dev->data.disk->bus == VIR_DOMAIN_DISK_BUS_XEN) {
if ((i = virDomainDiskIndexByName(vm->def,
- dev->data.disk->dst)) < 0) {
+ dev->data.disk->dst,
+ false)) < 0) {
libxlError(VIR_ERR_OPERATION_FAILED,
_("disk %s not found"),
dev->data.disk->dst);
goto cleanup;
@@ -3061,7 +3062,7 @@ libxlDomainAttachDeviceConfig(virDomainDefPtr vmdef,
virDomainDeviceDefPtr dev)
switch (dev->type) {
case VIR_DOMAIN_DEVICE_DISK:
disk = dev->data.disk;
- if (virDomainDiskIndexByName(vmdef, disk->dst) >= 0) {
+ if (virDomainDiskIndexByName(vmdef, disk->dst, true) >= 0) {
libxlError(VIR_ERR_INVALID_ARG,
_("target %s already exists."), disk->dst);
return -1;
@@ -3172,9 +3173,9 @@ libxlDomainUpdateDeviceConfig(virDomainDefPtr vmdef,
virDomainDeviceDefPtr dev)
switch (dev->type) {
case VIR_DOMAIN_DEVICE_DISK:
disk = dev->data.disk;
- if ((i = virDomainDiskIndexByName(vmdef, disk->dst)) < 0) {
+ if ((i = virDomainDiskIndexByName(vmdef, disk->dst, false)) < 0) {
libxlError(VIR_ERR_INVALID_ARG,
- _("target %s doesn't exists."), disk->dst);
+ _("target %s doesn't exist."), disk->dst);
goto cleanup;
}
orig = vmdef->disks[i];
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 31d2c7c..111214e 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -5349,7 +5349,7 @@ qemuDomainAttachDeviceConfig(virDomainDefPtr vmdef,
switch (dev->type) {
case VIR_DOMAIN_DEVICE_DISK:
disk = dev->data.disk;
- if (virDomainDiskIndexByName(vmdef, disk->dst) >= 0) {
+ if (virDomainDiskIndexByName(vmdef, disk->dst, true) >= 0) {
qemuReportError(VIR_ERR_INVALID_ARG,
_("target %s already exists."), disk->dst);
return -1;
@@ -5467,10 +5467,10 @@ qemuDomainUpdateDeviceConfig(virDomainDefPtr vmdef,
switch (dev->type) {
case VIR_DOMAIN_DEVICE_DISK:
disk = dev->data.disk;
- pos = virDomainDiskIndexByName(vmdef, disk->dst);
+ pos = virDomainDiskIndexByName(vmdef, disk->dst, false);
if (pos < 0) {
qemuReportError(VIR_ERR_INVALID_ARG,
- _("target %s doesn't exists."), disk->dst);
+ _("target %s doesn't exist."), disk->dst);
return -1;
}
orig = vmdef->disks[pos];
@@ -7209,7 +7209,8 @@ qemudDomainBlockPeek (virDomainPtr dom,
{
struct qemud_driver *driver = dom->conn->privateData;
virDomainObjPtr vm;
- int fd = -1, ret = -1, i;
+ int fd = -1, ret = -1;
+ const char *actual;
virCheckFlags(0, -1);
@@ -7231,42 +7232,35 @@ qemudDomainBlockPeek (virDomainPtr dom,
goto cleanup;
}
- /* Check the path belongs to this domain. */
- for (i = 0 ; i < vm->def->ndisks ; i++) {
- if (vm->def->disks[i]->src != NULL &&
- STREQ (vm->def->disks[i]->src, path)) {
- ret = 0;
- break;
- }
+ /* Check the path belongs to this domain. */
+ if (!(actual = virDomainDiskPathByName(vm->def, path))) {
+ qemuReportError(VIR_ERR_INVALID_ARG,
+ _("invalid path '%s'"), path);
+ goto cleanup;
}
+ path = actual;
- if (ret == 0) {
- ret = -1;
- /* The path is correct, now try to open it and get its size. */
- fd = open (path, O_RDONLY);
- if (fd == -1) {
- virReportSystemError(errno,
- _("%s: failed to open"), path);
- goto cleanup;
- }
-
- /* Seek and read. */
- /* NB. Because we configure with AC_SYS_LARGEFILE, off_t should
- * be 64 bits on all platforms.
- */
- if (lseek (fd, offset, SEEK_SET) == (off_t) -1 ||
- saferead (fd, buffer, size) == (ssize_t) -1) {
- virReportSystemError(errno,
- _("%s: failed to seek or read"), path);
- goto cleanup;
- }
+ /* The path is correct, now try to open it and get its size. */
+ fd = open (path, O_RDONLY);
+ if (fd == -1) {
+ virReportSystemError(errno,
+ _("%s: failed to open"), path);
+ goto cleanup;
+ }
- ret = 0;
- } else {
- qemuReportError(VIR_ERR_INVALID_ARG,
- "%s", _("invalid path"));
+ /* Seek and read. */
+ /* NB. Because we configure with AC_SYS_LARGEFILE, off_t should
+ * be 64 bits on all platforms.
+ */
+ if (lseek (fd, offset, SEEK_SET) == (off_t) -1 ||
+ saferead (fd, buffer, size) == (ssize_t) -1) {
+ virReportSystemError(errno,
+ _("%s: failed to seek or read"), path);
+ goto cleanup;
}
+ ret = 0;
+
cleanup:
VIR_FORCE_CLOSE(fd);
if (vm)
@@ -7381,8 +7375,8 @@ static int qemuDomainGetBlockInfo(virDomainPtr dom,
virStorageFileMetadata *meta = NULL;
virDomainDiskDefPtr disk = NULL;
struct stat sb;
- int i;
- int format;
+ int format; /* */
+ const char *actual;
virCheckFlags(0, -1);
@@ -7404,19 +7398,12 @@ static int qemuDomainGetBlockInfo(virDomainPtr dom,
}
/* Check the path belongs to this domain. */
- for (i = 0 ; i < vm->def->ndisks ; i++) {
- if (vm->def->disks[i]->src != NULL &&
- STREQ (vm->def->disks[i]->src, path)) {
- disk = vm->def->disks[i];
- break;
- }
- }
-
- if (!disk) {
+ if (!(actual = virDomainDiskPathByName(vm->def, path))) {
qemuReportError(VIR_ERR_INVALID_ARG,
_("invalid path %s not assigned to domain"), path);
goto cleanup;
}
+ path = actual;
/* The path is correct, now try to open it and get its size. */
fd = open (path, O_RDONLY);
@@ -9560,23 +9547,26 @@ static const char *
qemuDiskPathToAlias(virDomainObjPtr vm, const char *path) {
int i;
char *ret = NULL;
+ virDomainDiskDefPtr disk;
- for (i = 0 ; i < vm->def->ndisks ; i++) {
- virDomainDiskDefPtr disk = vm->def->disks[i];
+ i = virDomainDiskIndexByName(vm->def, path, true);
+ if (i < 0)
+ goto cleanup;
- if (disk->type != VIR_DOMAIN_DISK_TYPE_BLOCK &&
- disk->type != VIR_DOMAIN_DISK_TYPE_FILE)
- continue;
+ disk = vm->def->disks[i];
- if (disk->src != NULL && STREQ(disk->src, path)) {
- if (virAsprintf(&ret, "drive-%s", disk->info.alias) < 0)
{
- virReportOOMError();
- return NULL;
- }
- break;
+ if (disk->type != VIR_DOMAIN_DISK_TYPE_BLOCK &&
+ disk->type != VIR_DOMAIN_DISK_TYPE_FILE)
+ goto cleanup;
+
+ if (disk->src) {
+ if (virAsprintf(&ret, "drive-%s", disk->info.alias) < 0) {
+ virReportOOMError();
+ return NULL;
}
}
+cleanup:
if (!ret) {
qemuReportError(VIR_ERR_INVALID_ARG,
"%s", _("No device found for specified
path"));
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 27214ad..1accfad 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -192,15 +192,10 @@ static virDomainDiskDefPtr
qemuProcessFindDomainDiskByPath(virDomainObjPtr vm,
const char *path)
{
- int i;
-
- for (i = 0; i < vm->def->ndisks; i++) {
- virDomainDiskDefPtr disk;
+ int i = virDomainDiskIndexByName(vm->def, path, true);
- disk = vm->def->disks[i];
- if (disk->src != NULL && STREQ(disk->src, path))
- return disk;
- }
+ if (i >= 0)
+ return vm->def->disks[i];
qemuReportError(VIR_ERR_INTERNAL_ERROR,
_("no disk found with path %s"),
diff --git a/src/uml/uml_driver.c b/src/uml/uml_driver.c
index 19b6c55..75c8f27 100644
--- a/src/uml/uml_driver.c
+++ b/src/uml/uml_driver.c
@@ -2175,7 +2175,8 @@ umlDomainBlockPeek(virDomainPtr dom,
{
struct uml_driver *driver = dom->conn->privateData;
virDomainObjPtr vm;
- int fd = -1, ret = -1, i;
+ int fd = -1, ret = -1;
+ const char *actual;
virCheckFlags(0, -1);
@@ -2196,41 +2197,34 @@ umlDomainBlockPeek(virDomainPtr dom,
}
/* Check the path belongs to this domain. */
- for (i = 0 ; i < vm->def->ndisks ; i++) {
- if (vm->def->disks[i]->src != NULL &&
- STREQ (vm->def->disks[i]->src, path)) {
- ret = 0;
- break;
- }
+ if (!(actual = virDomainDiskPathByName(vm->def, path))) {
+ umlReportError(VIR_ERR_INVALID_ARG,
+ _("invalid path '%s'"), path);
+ goto cleanup;
}
+ path = actual;
- if (ret == 0) {
- ret = -1;
- /* The path is correct, now try to open it and get its size. */
- fd = open (path, O_RDONLY);
- if (fd == -1) {
- virReportSystemError(errno,
- _("cannot open %s"), path);
- goto cleanup;
- }
-
- /* Seek and read. */
- /* NB. Because we configure with AC_SYS_LARGEFILE, off_t should
- * be 64 bits on all platforms.
- */
- if (lseek (fd, offset, SEEK_SET) == (off_t) -1 ||
- saferead (fd, buffer, size) == (ssize_t) -1) {
- virReportSystemError(errno,
- _("cannot read %s"), path);
- goto cleanup;
- }
+ /* The path is correct, now try to open it and get its size. */
+ fd = open (path, O_RDONLY);
+ if (fd == -1) {
+ virReportSystemError(errno,
+ _("cannot open %s"), path);
+ goto cleanup;
+ }
- ret = 0;
- } else {
- umlReportError(VIR_ERR_INVALID_ARG, "%s",
- _("invalid path"));
+ /* Seek and read. */
+ /* NB. Because we configure with AC_SYS_LARGEFILE, off_t should
+ * be 64 bits on all platforms.
+ */
+ if (lseek (fd, offset, SEEK_SET) == (off_t) -1 ||
+ saferead (fd, buffer, size) == (ssize_t) -1) {
+ virReportSystemError(errno,
+ _("cannot read %s"), path);
+ goto cleanup;
}
+ ret = 0;
+
cleanup:
VIR_FORCE_CLOSE(fd);
if (vm)
diff --git a/src/xen/xend_internal.c b/src/xen/xend_internal.c
index 6d5a854..6d62431 100644
--- a/src/xen/xend_internal.c
+++ b/src/xen/xend_internal.c
@@ -3851,11 +3851,11 @@ xenDaemonDomainBlockPeek (virDomainPtr domain, const char *path,
xenUnifiedPrivatePtr priv;
struct sexpr *root = NULL;
int fd = -1, ret = -1;
- int found = 0, i;
virDomainDefPtr def;
int id;
char * tty;
int vncport;
+ const char *actual;
priv = (xenUnifiedPrivatePtr) domain->conn->privateData;
@@ -3891,18 +3891,12 @@ xenDaemonDomainBlockPeek (virDomainPtr domain, const char *path,
vncport)))
goto cleanup;
- for (i = 0 ; i < def->ndisks ; i++) {
- if (def->disks[i]->src &&
- STREQ(def->disks[i]->src, path)) {
- found = 1;
- break;
- }
- }
- if (!found) {
+ if (!(actual = virDomainDiskPathByName(def, path))) {
virXendError(VIR_ERR_INVALID_ARG,
_("%s: invalid path"), path);
goto cleanup;
}
+ path = actual;
/* The path is correct, now try to open it and get its size. */
fd = open (path, O_RDONLY);
diff --git a/tests/domainsnapshotxml2xmlin/disk_snapshot.xml
b/tests/domainsnapshotxml2xmlin/disk_snapshot.xml
index 1f0beb6..ee6b46a 100644
--- a/tests/domainsnapshotxml2xmlin/disk_snapshot.xml
+++ b/tests/domainsnapshotxml2xmlin/disk_snapshot.xml
@@ -2,7 +2,7 @@
<name>my snap name</name>
<description>!@#$%^</description>
<disks>
- <disk name='hda'/>
+ <disk name='/dev/HostVG/QEMUGuest1'/>
<disk name='hdb' snapshot='no'/>
<disk name='hdc' snapshot='internal'/>
<disk name='hdd' snapshot='external'>
diff --git a/tools/virsh.pod b/tools/virsh.pod
index c77b1e4..c37c9e4 100644
--- a/tools/virsh.pod
+++ b/tools/virsh.pod
@@ -429,7 +429,9 @@ the domain is persistent, these flags are ignored.
=item B<domblkstat> I<domain> I<block-device>
-Get device block stats for a running domain.
+Get device block stats for a running domain. A I<block-device> corresponds
+to a unique target name (<target dev='name'/>) or source file (<source
+file='name'/>) for one of the disk devices attached to I<domain>.
=item B<domifstat> I<domain> I<interface-device>
@@ -441,7 +443,9 @@ Get memory stats for a running domain.
=item B<domblkinfo> I<domain> I<block-device>
-Get block device size info for a domain.
+Get block device size info for a domain. A I<block-device> corresponds
+to a unique target name (<target dev='name'/>) or source file (<source
+file='name'/>) for one of the disk devices attached to I<domain>.
=item B<blockpull> I<domain> I<path> [I<bandwidth>]
--
1.7.4.4