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[libvirt] [PATCHv9 1/9] blockjob: add qemu capabilities related to block jobs



Upstream qemu 1.3 is adding two new monitor commands, 'drive-mirror'
and 'block-job-complete'[1], which can drive live block copy and
storage migration.  Additionally, RHEL 6.3 had backported an earlier
version of most of the same functionality, but under the names
'__com.redhat_drive-mirror' and '__com.redhat_drive-reopen' and with
slightly different JSON arguments, which we can support without too
much extra effort.

The libvirt API virDomainBlockRebase as already committed for 0.9.12
is flexible enough to expose the basics of block copy, but some
additional features in the 'drive-mirror' qemu command, such as
setting error policy, setting granularity, or using a persistent
bitmap, may later require a new libvirt API virDomainBlockCopy.  I
will wait to add that API until we know more about what qemu 1.3
will finally provide.

The use of two capability bits allows the bulk of libvirt code to
handle both RHEL 6.3 and upstream qemu 1.3 without caring about the
difference in monitor commands used; one bit that says whether the
commands are present, and another saying whether the RHEL 6.3
limitations are in effect.  The choice of XML names for the
capability bits is essential for interoperability with the RHEL 6.3
version of libvirt.

For consistency with other block job commands, libvirt must handle
the bandwidth argument as MiB/sec from the user, even though qemu
exposes the speed argument as bytes/sec; then again, qemu rounds
up to cluster size internally, so using MiB hides the worst effects
of that rounding if you pass small numbers.

[1]https://lists.gnu.org/archive/html/qemu-devel/2012-10/msg03256.html

* src/qemu/qemu_capabilities.h (QEMU_CAPS_DRIVE_MIRROR)
(QEMU_CAPS_DRIVE_REOPEN): New bits.
* src/qemu/qemu_capabilities.c (qemuCaps): Name them.
* src/qemu/qemu_monitor_json.c (qemuMonitorJSONCheckCommands): Set
them.
(qemuMonitorJSONDriveMirror, qemuMonitorDrivePivot): New functions.
* src/qemu/qemu_monitor_json.h (qemuMonitorJSONDriveMirror)
(qemuMonitorDrivePivot): Declare them.
* src/qemu/qemu_monitor.c (qemuMonitorDriveMirror)
(qemuMonitorDrivePivot): New passthroughs.
* src/qemu/qemu_monitor.h (qemuMonitorDriveMirror)
(qemuMonitorDrivePivot): Declare them.
---
 src/qemu/qemu_capabilities.c |  8 +++++
 src/qemu/qemu_capabilities.h |  2 ++
 src/qemu/qemu_monitor.c      | 56 ++++++++++++++++++++++++++++++--
 src/qemu/qemu_monitor.h      | 14 ++++++++
 src/qemu/qemu_monitor_json.c | 77 ++++++++++++++++++++++++++++++++++++++++++++
 src/qemu/qemu_monitor_json.h | 21 ++++++++++--
 6 files changed, 174 insertions(+), 4 deletions(-)

diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
index 115a054..2ce961d 100644
--- a/src/qemu/qemu_capabilities.c
+++ b/src/qemu/qemu_capabilities.c
@@ -189,6 +189,9 @@ VIR_ENUM_IMPL(qemuCaps, QEMU_CAPS_LAST,
               "seamless-migration",
               "block-commit",
               "vnc",
+
+              "drive-mirror", /* 115 */
+              "drive-reopen",
     );

 struct _qemuCaps {
@@ -1889,6 +1892,11 @@ qemuCapsProbeQMPCommands(qemuCapsPtr caps,
             qemuCapsSet(caps, QEMU_CAPS_BLOCK_COMMIT);
         else if (STREQ(name, "query-vnc"))
             qemuCapsSet(caps, QEMU_CAPS_VNC);
+        else if (STREQ(name, "drive-mirror") ||
+                 STREQ(name, "__com.redhat_drive-mirror"))
+            qemuCapsSet(caps, QEMU_CAPS_DRIVE_MIRROR);
+        else if (STREQ(name, "__com.redhat_drive-reopen"))
+            qemuCapsSet(caps, QEMU_CAPS_DRIVE_REOPEN);
         VIR_FREE(name);
     }
     VIR_FREE(commands);
diff --git a/src/qemu/qemu_capabilities.h b/src/qemu/qemu_capabilities.h
index 988dfdb..ddec6ff 100644
--- a/src/qemu/qemu_capabilities.h
+++ b/src/qemu/qemu_capabilities.h
@@ -152,6 +152,8 @@ enum qemuCapsFlags {
     QEMU_CAPS_SEAMLESS_MIGRATION = 112, /* seamless-migration for SPICE */
     QEMU_CAPS_BLOCK_COMMIT       = 113, /* block-commit */
     QEMU_CAPS_VNC                = 114, /* Is -vnc available? */
+    QEMU_CAPS_DRIVE_MIRROR       = 115, /* drive-mirror monitor command */
+    QEMU_CAPS_DRIVE_REOPEN       = 116, /* drive-reopen vs block-job-complete */

     QEMU_CAPS_LAST,                   /* this must always be the last item */
 };
diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c
index 2d9c44c..8e0fc43 100644
--- a/src/qemu/qemu_monitor.c
+++ b/src/qemu/qemu_monitor.c
@@ -2780,6 +2780,39 @@ qemuMonitorDiskSnapshot(qemuMonitorPtr mon, virJSONValuePtr actions,
     return ret;
 }

+/* Start a drive-mirror block job.  bandwidth is in MiB/sec.  */
+int
+qemuMonitorDriveMirror(qemuMonitorPtr mon,
+                       const char *device, const char *file,
+                       const char *format, unsigned long bandwidth,
+                       bool reopen, unsigned int flags)
+{
+    int ret = -1;
+    unsigned long long speed;
+
+    VIR_DEBUG("mon=%p, device=%s, file=%s, format=%s, bandwidth=%ld, "
+              "reopen=%d, flags=%x",
+              mon, device, file, NULLSTR(format), bandwidth, reopen, flags);
+
+    /* Convert bandwidth MiB to bytes */
+    speed = bandwidth;
+    if (speed > ULLONG_MAX / 1024 / 1024) {
+        virReportError(VIR_ERR_OVERFLOW,
+                       _("bandwidth must be less than %llu"),
+                       ULLONG_MAX / 1024 / 1024);
+        return -1;
+    }
+    speed <<= 20;
+
+    if (mon->json)
+        ret = qemuMonitorJSONDriveMirror(mon, device, file, format, speed,
+                                         reopen, flags);
+    else
+        virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                       _("drive-mirror requires JSON monitor"));
+    return ret;
+}
+
 /* Use the transaction QMP command to run atomic snapshot commands.  */
 int
 qemuMonitorTransaction(qemuMonitorPtr mon, virJSONValuePtr actions)
@@ -2796,7 +2829,7 @@ qemuMonitorTransaction(qemuMonitorPtr mon, virJSONValuePtr actions)
     return ret;
 }

-/* Start a block-commit block job.  bandwidth is in MB/sec.  */
+/* Start a block-commit block job.  bandwidth is in MiB/sec.  */
 int
 qemuMonitorBlockCommit(qemuMonitorPtr mon, const char *device,
                        const char *top, const char *base,
@@ -2826,6 +2859,25 @@ qemuMonitorBlockCommit(qemuMonitorPtr mon, const char *device,
     return ret;
 }

+/* Use the block-job-complete or drive-reopen monitor command to pivot
+ * a block copy job.  */
+int
+qemuMonitorDrivePivot(qemuMonitorPtr mon, const char *device,
+                      const char *file, const char *format, bool reopen)
+{
+    int ret = -1;
+
+    VIR_DEBUG("mon=%p, device=%s, file=%s, format=%s, reopen=%d",
+              mon, device, file, NULLSTR(format), reopen);
+
+    if (mon->json)
+        ret = qemuMonitorJSONDrivePivot(mon, device, file, format, reopen);
+    else
+        virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                       _("drive pivot requires JSON monitor"));
+    return ret;
+}
+
 int qemuMonitorArbitraryCommand(qemuMonitorPtr mon,
                                 const char *cmd,
                                 char **reply,
@@ -2893,7 +2945,7 @@ int qemuMonitorScreendump(qemuMonitorPtr mon,
     return ret;
 }

-/* bandwidth is in MB/sec */
+/* bandwidth is in MiB/sec */
 int qemuMonitorBlockJob(qemuMonitorPtr mon,
                         const char *device,
                         const char *base,
diff --git a/src/qemu/qemu_monitor.h b/src/qemu/qemu_monitor.h
index 8856d9f..8a33b6f 100644
--- a/src/qemu/qemu_monitor.h
+++ b/src/qemu/qemu_monitor.h
@@ -523,6 +523,20 @@ int qemuMonitorDiskSnapshot(qemuMonitorPtr mon,
                             bool reuse);
 int qemuMonitorTransaction(qemuMonitorPtr mon, virJSONValuePtr actions)
     ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);
+int qemuMonitorDriveMirror(qemuMonitorPtr mon,
+                           const char *device,
+                           const char *file,
+                           const char *format,
+                           unsigned long bandwidth,
+                           bool reopen,
+                           unsigned int flags)
+    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(3);
+int qemuMonitorDrivePivot(qemuMonitorPtr mon,
+                          const char *device,
+                          const char *file,
+                          const char *format,
+                          bool reopen)
+    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(3);

 int qemuMonitorBlockCommit(qemuMonitorPtr mon,
                            const char *device,
diff --git a/src/qemu/qemu_monitor_json.c b/src/qemu/qemu_monitor_json.c
index e495c0a..3b55041 100644
--- a/src/qemu/qemu_monitor_json.c
+++ b/src/qemu/qemu_monitor_json.c
@@ -3249,6 +3249,52 @@ cleanup:
     return ret;
 }

+/* speed is in bytes/sec */
+int
+qemuMonitorJSONDriveMirror(qemuMonitorPtr mon,
+                           const char *device, const char *file,
+                           const char *format, unsigned long long speed,
+                           bool reopen, unsigned int flags)
+{
+    int ret = -1;
+    virJSONValuePtr cmd;
+    virJSONValuePtr reply = NULL;
+    bool shallow = (flags & VIR_DOMAIN_BLOCK_REBASE_SHALLOW) != 0;
+    bool reuse = (flags & VIR_DOMAIN_BLOCK_REBASE_REUSE_EXT) != 0;
+
+    if (reopen)
+        cmd = qemuMonitorJSONMakeCommand("__com.redhat_drive-mirror",
+                                         "s:device", device,
+                                         "s:target", file,
+                                         "U:speed", speed,
+                                         "b:full", !shallow,
+                                         "s:mode",
+                                         reuse ? "existing" : "absolute-paths",
+                                         format ? "s:format" : NULL, format,
+                                         NULL);
+    else
+        cmd = qemuMonitorJSONMakeCommand("drive-mirror",
+                                         "s:device", device,
+                                         "s:target", file,
+                                         "U:speed", speed,
+                                         "s:sync", shallow ? "top" : "full",
+                                         "s:mode",
+                                         reuse ? "existing" : "absolute-paths",
+                                         format ? "s:format" : NULL, format,
+                                         NULL);
+    if (!cmd)
+        return -1;
+
+    if ((ret = qemuMonitorJSONCommand(mon, cmd, &reply)) < 0)
+        goto cleanup;
+    ret = qemuMonitorJSONCheckError(cmd, reply);
+
+cleanup:
+    virJSONValueFree(cmd);
+    virJSONValueFree(reply);
+    return ret;
+}
+
 int
 qemuMonitorJSONTransaction(qemuMonitorPtr mon, virJSONValuePtr actions)
 {
@@ -3306,6 +3352,37 @@ cleanup:
     return ret;
 }

+int
+qemuMonitorJSONDrivePivot(qemuMonitorPtr mon, const char *device,
+                          const char *file, const char *format, bool reopen)
+{
+    int ret;
+    virJSONValuePtr cmd;
+    virJSONValuePtr reply = NULL;
+
+    if (reopen)
+        cmd = qemuMonitorJSONMakeCommand("__com.redhat_drive-reopen",
+                                         "s:device", device,
+                                         "s:new-image-file", file,
+                                         format ? "s:format" : NULL, format,
+                                         NULL);
+    else
+        cmd = qemuMonitorJSONMakeCommand("block-job-complete",
+                                         "s:device", device,
+                                         NULL);
+    if (!cmd)
+        return -1;
+
+    if ((ret = qemuMonitorJSONCommand(mon, cmd, &reply)) < 0)
+        goto cleanup;
+    ret = qemuMonitorJSONCheckError(cmd, reply);
+
+cleanup:
+    virJSONValueFree(cmd);
+    virJSONValueFree(reply);
+    return ret;
+}
+

 int qemuMonitorJSONArbitraryCommand(qemuMonitorPtr mon,
                                     const char *cmd_str,
diff --git a/src/qemu/qemu_monitor_json.h b/src/qemu/qemu_monitor_json.h
index 61127a7..3dfe420 100644
--- a/src/qemu/qemu_monitor_json.h
+++ b/src/qemu/qemu_monitor_json.h
@@ -232,8 +232,25 @@ int qemuMonitorJSONDiskSnapshot(qemuMonitorPtr mon,
                                 const char *device,
                                 const char *file,
                                 const char *format,
-                                bool reuse);
-int qemuMonitorJSONTransaction(qemuMonitorPtr mon, virJSONValuePtr actions);
+                                bool reuse)
+    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(3)
+    ATTRIBUTE_NONNULL(4) ATTRIBUTE_NONNULL(5);
+int qemuMonitorJSONTransaction(qemuMonitorPtr mon, virJSONValuePtr actions)
+    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);
+int qemuMonitorJSONDriveMirror(qemuMonitorPtr mon,
+                               const char *device,
+                               const char *file,
+                               const char *format,
+                               unsigned long long speed,
+                               bool reopen,
+                               unsigned int flags)
+    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(3);
+int qemuMonitorJSONDrivePivot(qemuMonitorPtr mon,
+                              const char *device,
+                              const char *file,
+                              const char *format,
+                              bool reopen)
+    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(3);

 int qemuMonitorJSONBlockCommit(qemuMonitorPtr mon,
                                const char *device,
-- 
1.7.11.7


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