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Make 'top' optional to block commit

PATCH Applied Jeff Cody 4 participants 8 messages Jun 25, 2014 – Jun 30, 2014

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#1 lore raw

PATCH v7 1/2 block: simplify bdrv_find_base() and bdrv_find_overlay()

In reply to Jeff Cody

This simplifies the function bdrv_find_overlay(). With this change, bdrv_find_base() is just a subset of usage of bdrv_find_overlay(), so this also takes advantage of that.

Reviewed-by Eric Blake <[email protected]>
Reviewed-by Benoit Canet <[email protected]>
Signed-off-by Jeff Cody <[email protected]>
---
 block.c | 45 ++++++++++-----------------------------------
 1 file changed, 10 insertions(+), 35 deletions(-)
block.c +10 -35
index 217f523..a91809c 100644
@@ -2513,32 +2513,23 @@ int bdrv_change_backing_file(BlockDriverState *bs,
  *
  * Returns NULL if bs is not found in active's image chain,
  * or if active == bs.
+ *
+ * Returns the bottommost base image if bs == NULL.
  */
 BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
                                     BlockDriverState *bs)
 {
-    BlockDriverState *overlay = NULL;
-    BlockDriverState *intermediate;
-
-    assert(active != NULL);
-    assert(bs != NULL);
-
-    /* if bs is the same as active, then by definition it has no overlay
-     */
-    if (active == bs) {
-        return NULL;
+    while (active && bs != active->backing_hd) {
+        active = active->backing_hd;
     }
 
-    intermediate = active;
-    while (intermediate->backing_hd) {
-        if (intermediate->backing_hd == bs) {
-            overlay = intermediate;
-            break;
-        }
-        intermediate = intermediate->backing_hd;
-    }
+    return active;
+}
 
-    return overlay;
+/* Given a BDS, searches for the base layer. */
+BlockDriverState *bdrv_find_base(BlockDriverState *bs)
+{
+    return bdrv_find_overlay(bs, NULL);
 }
 
 typedef struct BlkIntermediateStates {

@@ -4333,22 +4324,6 @@ int bdrv_get_backing_file_depth(BlockDriverState *bs)
     return 1 + bdrv_get_backing_file_depth(bs->backing_hd);
 }
 
-BlockDriverState *bdrv_find_base(BlockDriverState *bs)
-{
-    BlockDriverState *curr_bs = NULL;
-
-    if (!bs) {
-        return NULL;
-    }
-
-    curr_bs = bs;
-
-    while (curr_bs->backing_hd) {
-        curr_bs = curr_bs->backing_hd;
-    }
-    return curr_bs;
-}
-
 /**************************************************************/
 /* async I/Os */
Signature · 1 line
1.9.3

Jeff Cody

author
#0 lore raw

v7 cover Make 'top' optional to block commit

This is a split of the previous series "Modify block jobs to use node-names"

This series includes some function cleanup, and making 'top' optional for block-commit. This in turns makes it easier for libvirt to probe that 2.1 supports commit of the active layer.

Jeff Cody (2):
block: simplify bdrv_find_base() and bdrv_find_overlay()
block: make 'top' argument to block-commit optional

 block.c                | 45 ++++++++++-----------------------------------
 blockdev.c             | 16 ++++++++++++++--
 qapi/block-core.json   |  7 ++++---
 qmp-commands.hx        |  5 +++--
 tests/qemu-iotests/040 | 28 ++++++++++++++++++----------
 5 files changed, 49 insertions(+), 52 deletions(-)
Signature · 1 line
1.9.3
author
#2 lore raw

PATCH v7 2/2 block: make 'top' argument to block-commit optional

Now that active layer block-commit is supported, the 'top' argument no longer needs to be mandatory.

Change it to optional, with the default being the active layer in the device chain.

Reviewed-by Eric Blake <[email protected]>
Reviewed-by Benoit Canet <[email protected]>
Signed-off-by Jeff Cody <[email protected]>
---
 blockdev.c             | 16 ++++++++++++++--
 qapi/block-core.json   |  7 ++++---
 qmp-commands.hx        |  5 +++--
 tests/qemu-iotests/040 | 28 ++++++++++++++++++----------
 4 files changed, 39 insertions(+), 17 deletions(-)
blockdev.c +14 -2
index 03ab153..858bd75 100644
@@ -1908,7 +1908,8 @@ void qmp_block_stream(const char *device, bool has_base,
 }
 
 void qmp_block_commit(const char *device,
-                      bool has_base, const char *base, const char *top,
+                      bool has_base, const char *base,
+                      bool has_top, const char *top,
                       bool has_speed, int64_t speed,
                       Error **errp)
 {

@@ -1927,6 +1928,11 @@ void qmp_block_commit(const char *device,
     /* drain all i/o before commits */
     bdrv_drain_all();
 
+    /* Important Note:
+     *  libvirt relies on the DeviceNotFound error class in order to probe for
+     *  live commit feature versions; for this to work, we must make sure to
+     *  perform the device lookup before any generic errors that may occur in a
+     *  scenario in which all optional arguments are omitted. */
     bs = bdrv_find(device);
     if (!bs) {
         error_set(errp, QERR_DEVICE_NOT_FOUND, device);

@@ -1940,7 +1946,7 @@ void qmp_block_commit(const char *device,
     /* default top_bs is the active layer */
     top_bs = bs;
 
-    if (top) {
+    if (has_top && top) {
         if (strcmp(bs->filename, top) != 0) {
             top_bs = bdrv_find_backing_image(bs, top);
         }

@@ -1962,6 +1968,12 @@ void qmp_block_commit(const char *device,
         return;
     }
 
+    /* Do not allow attempts to commit an image into itself */
+    if (top_bs == base_bs) {
+        error_setg(errp, "cannot commit an image into itself");
+        return;
+    }
+
     if (top_bs == bs) {
         commit_active_start(bs, base_bs, speed, on_error, block_job_cb,
                             bs, &local_err);
qapi/block-core.json +4 -3
index af6b436..ecd90ee 100644
@@ -690,8 +690,9 @@
 # @base:   #optional The file name of the backing image to write data into.
 #                    If not specified, this is the deepest backing image
 #
-# @top:              The file name of the backing image within the image chain,
-#                    which contains the topmost data to be committed down.
+# @top:    #optional The file name of the backing image within the image chain,
+#                    which contains the topmost data to be committed down. If
+#                    not specified, this is the active layer.
 #
 #                    If top == base, that is an error.
 #                    If top == active, the job will not be completed by itself,

@@ -719,7 +720,7 @@
 #
 ##
 { 'command': 'block-commit',
-  'data': { 'device': 'str', '*base': 'str', 'top': 'str',
+  'data': { 'device': 'str', '*base': 'str', '*top': 'str',
             '*speed': 'int' } }
 
 ##
qmp-commands.hx +3 -2
index e4a1c80..a6a8fec 100644
@@ -985,7 +985,7 @@ EQMP
 
     {
         .name       = "block-commit",
-        .args_type  = "device:B,base:s?,top:s,speed:o?",
+        .args_type  = "device:B,base:s?,top:s?,speed:o?",
         .mhandler.cmd_new = qmp_marshal_input_block_commit,
     },
 

@@ -1003,7 +1003,8 @@ Arguments:
           If not specified, this is the deepest backing image
           (json-string, optional)
 - "top":  The file name of the backing image within the image chain,
-          which contains the topmost data to be committed down.
+          which contains the topmost data to be committed down. If
+          not specified, this is the active layer. (json-string, optional)
 
           If top == base, that is an error.
           If top == active, the job will not be completed by itself,
tests/qemu-iotests/040 +18 -10
index 734b6a6..803b0c7 100755
@@ -35,11 +35,7 @@ test_img = os.path.join(iotests.test_dir, 'test.img')
 class ImageCommitTestCase(iotests.QMPTestCase):
     '''Abstract base class for image commit test cases'''
 
-    def run_commit_test(self, top, base):
-        self.assert_no_active_block_jobs()
-        result = self.vm.qmp('block-commit', device='drive0', top=top, base=base)
-        self.assert_qmp(result, 'return', {})
-
+    def wait_for_complete(self):
         completed = False
         while not completed:
             for event in self.vm.get_qmp_events(wait=True):

@@ -58,6 +54,18 @@ class ImageCommitTestCase(iotests.QMPTestCase):
         self.assert_no_active_block_jobs()
         self.vm.shutdown()
 
+    def run_commit_test(self, top, base):
+        self.assert_no_active_block_jobs()
+        result = self.vm.qmp('block-commit', device='drive0', top=top, base=base)
+        self.assert_qmp(result, 'return', {})
+        self.wait_for_complete()
+
+    def run_default_commit_test(self):
+        self.assert_no_active_block_jobs()
+        result = self.vm.qmp('block-commit', device='drive0')
+        self.assert_qmp(result, 'return', {})
+        self.wait_for_complete()
+
 class TestSingleDrive(ImageCommitTestCase):
     image_len = 1 * 1024 * 1024
     test_len = 1 * 1024 * 256

@@ -109,17 +117,17 @@ class TestSingleDrive(ImageCommitTestCase):
         self.assertEqual(-1, qemu_io('-c', 'read -P 0xab 0 524288', backing_img).find("verification failed"))
         self.assertEqual(-1, qemu_io('-c', 'read -P 0xef 524288 524288', backing_img).find("verification failed"))
 
+    def test_top_is_default_active(self):
+        self.run_default_commit_test()
+        self.assertEqual(-1, qemu_io('-c', 'read -P 0xab 0 524288', backing_img).find("verification failed"))
+        self.assertEqual(-1, qemu_io('-c', 'read -P 0xef 524288 524288', backing_img).find("verification failed"))
+
     def test_top_and_base_reversed(self):
         self.assert_no_active_block_jobs()
         result = self.vm.qmp('block-commit', device='drive0', top='%s' % backing_img, base='%s' % mid_img)
         self.assert_qmp(result, 'error/class', 'GenericError')
         self.assert_qmp(result, 'error/desc', 'Base \'%s\' not found' % mid_img)
 
-    def test_top_omitted(self):
-        self.assert_no_active_block_jobs()
-        result = self.vm.qmp('block-commit', device='drive0')
-        self.assert_qmp(result, 'error/class', 'GenericError')
-        self.assert_qmp(result, 'error/desc', "Parameter 'top' is missing")
 
 class TestRelativePaths(ImageCommitTestCase):
     image_len = 1 * 1024 * 1024
Signature · 1 line
1.9.3
author
#4 lore raw
In reply to Jeff Cody
Quoted 10 lines · Jeff Cody

This is a split of the previous series "Modify block jobs to use node-names"

This series includes some function cleanup, and making 'top' optional for block-commit. This in turns makes it easier for libvirt to probe that 2.1 supports commit of the active layer.

Jeff Cody (2):
block: simplify bdrv_find_base() and bdrv_find_overlay()
block: make 'top' argument to block-commit optional

Quoted 10 lines
 block.c                | 45 ++++++++++-----------------------------------
 blockdev.c             | 16 ++++++++++++++--
 qapi/block-core.json   |  7 ++++---
 qmp-commands.hx        |  5 +++--
 tests/qemu-iotests/040 | 28 ++++++++++++++++++----------
 5 files changed, 49 insertions(+), 52 deletions(-)
Signature · 1 line
1.9.3

Eric,

Sorry, meant to cc you on this series

#5 lore raw
In reply to Jeff Cody
Quoted 9 lines · Jeff Cody

This is a split of the previous series "Modify block jobs to use node-names"

This series includes some function cleanup, and making 'top' optional for block-commit. This in turns makes it easier for libvirt to probe that 2.1 supports commit of the active layer.

Jeff Cody (2):
block: simplify bdrv_find_base() and bdrv_find_overlay()
block: make 'top' argument to block-commit optional

This series is ready to go now, and should be non-controversial.

Signature · 2 lines
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org
Reviewed-by on the v7 series
#6 lore raw
In reply to Jeff Cody

Am 25.06.2014 um 21:35 hat Jeff Cody geschrieben:

Quoted 9 lines

This is a split of the previous series "Modify block jobs to use node-names"

This series includes some function cleanup, and making 'top' optional for block-commit. This in turns makes it easier for libvirt to probe that 2.1 supports commit of the active layer.

Jeff Cody (2):
block: simplify bdrv_find_base() and bdrv_find_overlay()
block: make 'top' argument to block-commit optional

Reviewed-by Kevin Wolf <[email protected]>

Patch 2 has a conflict in the test case. I'll post a v8 for it.

#3 lore raw

PATCH v8 2/2 block: make 'top' argument to block-commit optional

In reply to Jeff Cody

From: Jeff Cody <[email protected]>

Now that active layer block-commit is supported, the 'top' argument no longer needs to be mandatory.

Change it to optional, with the default being the active layer in the device chain.

[kwolf: Rebased and resolved conflict in tests/qemu-iotests/040]

Reviewed-by Eric Blake <[email protected]>
Reviewed-by Benoit Canet <[email protected]>
Signed-off-by Jeff Cody <[email protected]>
Signed-off-by Kevin Wolf <[email protected]>
---
 blockdev.c             | 16 ++++++++++++++--
 qapi/block-core.json   |  7 ++++---
 qmp-commands.hx        |  5 +++--
 tests/qemu-iotests/040 | 28 ++++++++++++++++++----------
 4 files changed, 39 insertions(+), 17 deletions(-)
blockdev.c +14 -2
index 69b7c2a..79ce52b 100644
@@ -1913,7 +1913,8 @@ void qmp_block_stream(const char *device, bool has_base,
 }
 
 void qmp_block_commit(const char *device,
-                      bool has_base, const char *base, const char *top,
+                      bool has_base, const char *base,
+                      bool has_top, const char *top,
                       bool has_speed, int64_t speed,
                       Error **errp)
 {

@@ -1932,6 +1933,11 @@ void qmp_block_commit(const char *device,
     /* drain all i/o before commits */
     bdrv_drain_all();
 
+    /* Important Note:
+     *  libvirt relies on the DeviceNotFound error class in order to probe for
+     *  live commit feature versions; for this to work, we must make sure to
+     *  perform the device lookup before any generic errors that may occur in a
+     *  scenario in which all optional arguments are omitted. */
     bs = bdrv_find(device);
     if (!bs) {
         error_set(errp, QERR_DEVICE_NOT_FOUND, device);

@@ -1945,7 +1951,7 @@ void qmp_block_commit(const char *device,
     /* default top_bs is the active layer */
     top_bs = bs;
 
-    if (top) {
+    if (has_top && top) {
         if (strcmp(bs->filename, top) != 0) {
             top_bs = bdrv_find_backing_image(bs, top);
         }

@@ -1967,6 +1973,12 @@ void qmp_block_commit(const char *device,
         return;
     }
 
+    /* Do not allow attempts to commit an image into itself */
+    if (top_bs == base_bs) {
+        error_setg(errp, "cannot commit an image into itself");
+        return;
+    }
+
     if (top_bs == bs) {
         commit_active_start(bs, base_bs, speed, on_error, block_job_cb,
                             bs, &local_err);
qapi/block-core.json +4 -3
index faf394c..6a697f1 100644
@@ -690,8 +690,9 @@
 # @base:   #optional The file name of the backing image to write data into.
 #                    If not specified, this is the deepest backing image
 #
-# @top:              The file name of the backing image within the image chain,
-#                    which contains the topmost data to be committed down.
+# @top:    #optional The file name of the backing image within the image chain,
+#                    which contains the topmost data to be committed down. If
+#                    not specified, this is the active layer.
 #
 #                    If top == base, that is an error.
 #                    If top == active, the job will not be completed by itself,

@@ -719,7 +720,7 @@
 #
 ##
 { 'command': 'block-commit',
-  'data': { 'device': 'str', '*base': 'str', 'top': 'str',
+  'data': { 'device': 'str', '*base': 'str', '*top': 'str',
             '*speed': 'int' } }
 
 ##
qmp-commands.hx +3 -2
index 1ea18b2..8c5fdb5 100644
@@ -985,7 +985,7 @@ EQMP
 
     {
         .name       = "block-commit",
-        .args_type  = "device:B,base:s?,top:s,speed:o?",
+        .args_type  = "device:B,base:s?,top:s?,speed:o?",
         .mhandler.cmd_new = qmp_marshal_input_block_commit,
     },
 

@@ -1003,7 +1003,8 @@ Arguments:
           If not specified, this is the deepest backing image
           (json-string, optional)
 - "top":  The file name of the backing image within the image chain,
-          which contains the topmost data to be committed down.
+          which contains the topmost data to be committed down. If
+          not specified, this is the active layer. (json-string, optional)
 
           If top == base, that is an error.
           If top == active, the job will not be completed by itself,
tests/qemu-iotests/040 +18 -10
index d166810..f1e16c1 100755
@@ -35,11 +35,7 @@ test_img = os.path.join(iotests.test_dir, 'test.img')
 class ImageCommitTestCase(iotests.QMPTestCase):
     '''Abstract base class for image commit test cases'''
 
-    def run_commit_test(self, top, base, need_ready=False):
-        self.assert_no_active_block_jobs()
-        result = self.vm.qmp('block-commit', device='drive0', top=top, base=base)
-        self.assert_qmp(result, 'return', {})
-
+    def wait_for_complete(self, need_ready=False):
         completed = False
         ready = False
         while not completed:

@@ -62,6 +58,18 @@ class ImageCommitTestCase(iotests.QMPTestCase):
         self.assert_no_active_block_jobs()
         self.vm.shutdown()
 
+    def run_commit_test(self, top, base, need_ready=False):
+        self.assert_no_active_block_jobs()
+        result = self.vm.qmp('block-commit', device='drive0', top=top, base=base)
+        self.assert_qmp(result, 'return', {})
+        self.wait_for_complete(need_ready)
+
+    def run_default_commit_test(self):
+        self.assert_no_active_block_jobs()
+        result = self.vm.qmp('block-commit', device='drive0')
+        self.assert_qmp(result, 'return', {})
+        self.wait_for_complete()
+
 class TestSingleDrive(ImageCommitTestCase):
     image_len = 1 * 1024 * 1024
     test_len = 1 * 1024 * 256

@@ -113,17 +121,17 @@ class TestSingleDrive(ImageCommitTestCase):
         self.assertEqual(-1, qemu_io('-c', 'read -P 0xab 0 524288', backing_img).find("verification failed"))
         self.assertEqual(-1, qemu_io('-c', 'read -P 0xef 524288 524288', backing_img).find("verification failed"))
 
+    def test_top_is_default_active(self):
+        self.run_default_commit_test()
+        self.assertEqual(-1, qemu_io('-c', 'read -P 0xab 0 524288', backing_img).find("verification failed"))
+        self.assertEqual(-1, qemu_io('-c', 'read -P 0xef 524288 524288', backing_img).find("verification failed"))
+
     def test_top_and_base_reversed(self):
         self.assert_no_active_block_jobs()
         result = self.vm.qmp('block-commit', device='drive0', top='%s' % backing_img, base='%s' % mid_img)
         self.assert_qmp(result, 'error/class', 'GenericError')
         self.assert_qmp(result, 'error/desc', 'Base \'%s\' not found' % mid_img)
 
-    def test_top_omitted(self):
-        self.assert_no_active_block_jobs()
-        result = self.vm.qmp('block-commit', device='drive0')
-        self.assert_qmp(result, 'error/class', 'GenericError')
-        self.assert_qmp(result, 'error/desc', "Parameter 'top' is missing")
 
 class TestRelativePaths(ImageCommitTestCase):
     image_len = 1 * 1024 * 1024
Signature · 1 line
1.8.3.1
Applied
#7 lore raw
In reply to Jeff Cody
Quoted 10 lines · Jeff Cody

This is a split of the previous series "Modify block jobs to use node-names"

This series includes some function cleanup, and making 'top' optional for block-commit. This in turns makes it easier for libvirt to probe that 2.1 supports commit of the active layer.

Jeff Cody (2):
block: simplify bdrv_find_base() and bdrv_find_overlay()
block: make 'top' argument to block-commit optional

Quoted 11 lines
 block.c                | 45 ++++++++++-----------------------------------
 blockdev.c             | 16 ++++++++++++++--
 qapi/block-core.json   |  7 ++++---
 qmp-commands.hx        |  5 +++--
 tests/qemu-iotests/040 | 28 ++++++++++++++++++----------
 5 files changed, 49 insertions(+), 52 deletions(-)
Signature · 1 line
1.9.3

Thanks, applied to my block tree:
https://github.com/stefanha/qemu/commits/block

Stefan