block: Skip implicit nodes in query-block/blockstats

Commits 0db832f and 6cdbceb introduced the automatic insertion of filter
nodes above the top layer of mirror and commit block jobs. The
assumption made there was that since libvirt doesn't do node-level
management of the block layer yet, it shouldn't be affected by added
nodes.

This is true as far as commands issued by libvirt are concerned. It only
uses BlockBackend names to address nodes, so any operations it performs
still operate on the root of the tree as intended.

However, the assumption breaks down when you consider query commands,
which return data for the wrong node now. These commands also return
information on some child nodes (bs->file and/or bs->backing), which
libvirt does make use of, and which refer to the wrong nodes, too.

One of the consequences is that oVirt gets wrong information about the
image size and stops the VM in response as long as a mirror or commit
job is running:

https://bugzilla.redhat.com/show_bug.cgi?id=1470634

This patch fixes the problem by hiding the implicit nodes created
automatically by the mirror and commit block jobs in the output of
query-block and BlockBackend-based query-blockstats as long as the user
doesn't indicate that they are aware of those nodes by providing a node
name for them in the QMP command to start the block job.

The node-based commands query-named-block-nodes and query-blockstats
with query-nodes=true still show all nodes, including implicit ones.
This ensures that users that are capable of node-level management can
still access the full information; users that only know BlockBackends
won't use these commands.

Cc: qemu-stable@nongnu.org
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Tested-by: Eric Blake <eblake@redhat.com>
(cherry picked from commit d3c8c67469ee70fcae116d5abc277a7ebc8a19fd)
 Conflicts:
	block/qapi.c
	include/block/block_int.h
* fix context deps on 46eade7b and 5a9347c6
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

diff --git a/block.c b/block.c
index 21cb65ebf3b0ba7295d1bb93f9a2a81366630585..46ea4a3bd579668001bf8c68529167f3b5b4cd10 100644 (file)
--- a/block.c
+++ b/block.c
@@ -3863,19 +3863,6 @@ BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
     return retval;
 }
 
-int bdrv_get_backing_file_depth(BlockDriverState *bs)
-{
-    if (!bs->drv) {
-        return 0;
-    }
-
-    if (!bs->backing) {
-        return 0;
-    }
-
-    return 1 + bdrv_get_backing_file_depth(bs->backing->bs);
-}
-
 void bdrv_init(void)
 {
     module_call_init(MODULE_INIT_BLOCK);

diff --git a/block/commit.c b/block/commit.c
index 66e3418e74d3e121b274c86d6011ee82f17b7ec3..b4c1be799ba62dc3f6b6fe3f716ffb5bd6b4c82d 100644 (file)
--- a/block/commit.c
+++ b/block/commit.c
@@ -351,6 +351,9 @@ void commit_start(const char *job_id, BlockDriverState *bs,
     if (commit_top_bs == NULL) {
         goto fail;
     }
+    if (!filter_node_name) {
+        commit_top_bs->implicit = true;
+    }
     commit_top_bs->total_sectors = top->total_sectors;
     bdrv_set_aio_context(commit_top_bs, bdrv_get_aio_context(top));
 

diff --git a/block/mirror.c b/block/mirror.c
index 4e8f124c30a1f33d8ffeb3fb056052588339de09..9bf5f8995c4488aa6bd092e8182e633e638b12dd 100644 (file)
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -1152,6 +1152,9 @@ static void mirror_start_job(const char *job_id, BlockDriverState *bs,
     if (mirror_top_bs == NULL) {
         return;
     }
+    if (!filter_node_name) {
+        mirror_top_bs->implicit = true;
+    }
     mirror_top_bs->total_sectors = bs->total_sectors;
     bdrv_set_aio_context(mirror_top_bs, bdrv_get_aio_context(bs));
 

diff --git a/block/qapi.c b/block/qapi.c
index a40922ea2616b0d87d423f2909776b8ad796acf5..803205b0b651f4bc630abbf5b85ce8f2b1b55f62 100644 (file)
--- a/block/qapi.c
+++ b/block/qapi.c
@@ -64,7 +64,6 @@ BlockDeviceInfo *bdrv_block_device_info(BlockBackend *blk,
         info->backing_file = g_strdup(bs->backing_file);
     }
 
-    info->backing_file_depth = bdrv_get_backing_file_depth(bs);
     info->detect_zeroes = bs->detect_zeroes;
 
     if (blk && blk_get_public(blk)->throttle_state) {
@@ -125,6 +124,7 @@ BlockDeviceInfo *bdrv_block_device_info(BlockBackend *blk,
 
     bs0 = bs;
     p_image_info = &info->image;
+    info->backing_file_depth = 0;
     while (1) {
         Error *local_err = NULL;
         bdrv_query_image_info(bs0, p_image_info, &local_err);
@@ -133,13 +133,21 @@ BlockDeviceInfo *bdrv_block_device_info(BlockBackend *blk,
             qapi_free_BlockDeviceInfo(info);
             return NULL;
         }
+
         if (bs0->drv && bs0->backing) {
+            info->backing_file_depth++;
             bs0 = bs0->backing->bs;
             (*p_image_info)->has_backing_image = true;
             p_image_info = &((*p_image_info)->backing_image);
         } else {
             break;
         }
+
+        /* Skip automatically inserted nodes that the user isn't aware of for
+         * query-block (blk != NULL), but not for query-named-block-nodes */
+        while (blk && bs0 && bs0->drv && bs0->implicit) {
+            bs0 = backing_bs(bs0);
+        }
     }
 
     return info;
@@ -322,6 +330,12 @@ static void bdrv_query_info(BlockBackend *blk, BlockInfo **p_info,
 {
     BlockInfo *info = g_malloc0(sizeof(*info));
     BlockDriverState *bs = blk_bs(blk);
+
+    /* Skip automatically inserted nodes that the user isn't aware of */
+    while (bs && bs->drv && bs->implicit) {
+        bs = backing_bs(bs);
+    }
+
     info->device = g_strdup(blk_name(blk));
     info->type = g_strdup("unknown");
     info->locked = blk_dev_is_medium_locked(blk);
@@ -424,8 +438,8 @@ static void bdrv_query_blk_stats(BlockDeviceStats *ds, BlockBackend *blk)
     }
 }
 
-static BlockStats *bdrv_query_bds_stats(const BlockDriverState *bs,
-                                 bool query_backing)
+static BlockStats *bdrv_query_bds_stats(BlockDriverState *bs,
+                                        bool blk_level)
 {
     BlockStats *s = NULL;
 
@@ -436,6 +450,14 @@ static BlockStats *bdrv_query_bds_stats(const BlockDriverState *bs,
         return s;
     }
 
+    /* Skip automatically inserted nodes that the user isn't aware of in
+     * a BlockBackend-level command. Stay at the exact node for a node-level
+     * command. */
+    while (blk_level && bs->drv && bs->implicit) {
+        bs = backing_bs(bs);
+        assert(bs);
+    }
+
     if (bdrv_get_node_name(bs)[0]) {
         s->has_node_name = true;
         s->node_name = g_strdup(bdrv_get_node_name(bs));
@@ -445,12 +467,12 @@ static BlockStats *bdrv_query_bds_stats(const BlockDriverState *bs,
 
     if (bs->file) {
         s->has_parent = true;
-        s->parent = bdrv_query_bds_stats(bs->file->bs, query_backing);
+        s->parent = bdrv_query_bds_stats(bs->file->bs, blk_level);
     }
 
-    if (query_backing && bs->backing) {
+    if (blk_level && bs->backing) {
         s->has_backing = true;
-        s->backing = bdrv_query_bds_stats(bs->backing->bs, query_backing);
+        s->backing = bdrv_query_bds_stats(bs->backing->bs, blk_level);
     }
 
     return s;

diff --git a/include/block/block.h b/include/block/block.h
index 4bf4843d83aa8b2c13d7211682d036855f72bbdc..060c08c086ed356f9846ebfae3551901a1d18947 100644 (file)
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -292,7 +292,6 @@ int coroutine_fn bdrv_co_pwrite_zeroes(BdrvChild *child, int64_t offset,
                                        int count, BdrvRequestFlags flags);
 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
     const char *backing_file);
-int bdrv_get_backing_file_depth(BlockDriverState *bs);
 void bdrv_refresh_filename(BlockDriverState *bs);
 int bdrv_truncate(BdrvChild *child, int64_t offset, Error **errp);
 int64_t bdrv_nb_sectors(BlockDriverState *bs);

diff --git a/include/block/block_int.h b/include/block/block_int.h
index 59400bd8480b94f9428090cde6a5e69508f2f74e..89d7b458e7ad330ea72cf5e47fb291e98448b482 100644 (file)
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -518,6 +518,7 @@ struct BlockDriverState {
     bool valid_key; /* if true, a valid encryption key has been set */
     bool sg;        /* if true, the device is a /dev/sg* */
     bool probed;    /* if true, format was probed rather than specified */
+    bool implicit;  /* if true, this filter node was automatically inserted */
 
     BlockDriver *drv; /* NULL means no media */
     void *opaque;

diff --git a/qapi/block-core.json b/qapi/block-core.json
index 38edadae959cd19ee7475b7ee96a0c6d41f65ae9..7ce90ec94013c3e5d4e71fa09fc23de6c4047ceb 100644 (file)
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -467,7 +467,8 @@
 #
 # Get a list of BlockInfo for all virtual block devices.
 #
-# Returns: a list of @BlockInfo describing each virtual block device
+# Returns: a list of @BlockInfo describing each virtual block device. Filter
+# nodes that were created implicitly are skipped over.
 #
 # Since: 0.14.0
 #
@@ -723,7 +724,8 @@
 #               information, but not "backing".
 #               If false or omitted, the behavior is as before - query all the
 #               device backends, recursively including their "parent" and
-#               "backing". (Since 2.3)
+#               "backing". Filter nodes that were created implicitly are
+#               skipped over in this mode. (Since 2.3)
 #
 # Returns: A list of @BlockStats for each virtual block devices.
 #

diff --git a/tests/qemu-iotests/040 b/tests/qemu-iotests/040
index 9d381d9b72946d9dd1365869c95e93b98ef7714f..95b7510571dc18853ff83af964c9fe21a896dd51 100755 (executable)
--- a/tests/qemu-iotests/040
+++ b/tests/qemu-iotests/040
@@ -81,7 +81,7 @@ class TestSingleDrive(ImageCommitTestCase):
         qemu_img('create', '-f', iotests.imgfmt, '-o', 'backing_file=%s' % mid_img, test_img)
         qemu_io('-f', 'raw', '-c', 'write -P 0xab 0 524288', backing_img)
         qemu_io('-f', iotests.imgfmt, '-c', 'write -P 0xef 524288 524288', mid_img)
-        self.vm = iotests.VM().add_drive(test_img, interface="none")
+        self.vm = iotests.VM().add_drive(test_img, "node-name=top,backing.node-name=mid,backing.backing.node-name=base", interface="none")
         self.vm.add_device("virtio-scsi-pci")
         self.vm.add_device("scsi-hd,id=scsi0,drive=drive0")
         self.vm.launch()
@@ -163,6 +163,34 @@ class TestSingleDrive(ImageCommitTestCase):
 
         self.assert_no_active_block_jobs()
 
+    # Tests that the insertion of the commit_top filter node doesn't make a
+    # difference to query-blockstat
+    def test_implicit_node(self):
+        if self.image_len == 0:
+            return
+
+        self.assert_no_active_block_jobs()
+        result = self.vm.qmp('block-commit', device='drive0', top=mid_img,
+                             base=backing_img, speed=(self.image_len / 4))
+        self.assert_qmp(result, 'return', {})
+
+        result = self.vm.qmp('query-block')
+        self.assert_qmp(result, 'return[0]/inserted/file', test_img)
+        self.assert_qmp(result, 'return[0]/inserted/drv', iotests.imgfmt)
+        self.assert_qmp(result, 'return[0]/inserted/backing_file', mid_img)
+        self.assert_qmp(result, 'return[0]/inserted/backing_file_depth', 2)
+        self.assert_qmp(result, 'return[0]/inserted/image/filename', test_img)
+        self.assert_qmp(result, 'return[0]/inserted/image/backing-image/filename', mid_img)
+        self.assert_qmp(result, 'return[0]/inserted/image/backing-image/backing-image/filename', backing_img)
+
+        result = self.vm.qmp('query-blockstats')
+        self.assert_qmp(result, 'return[0]/node-name', 'top')
+        self.assert_qmp(result, 'return[0]/backing/node-name', 'mid')
+        self.assert_qmp(result, 'return[0]/backing/backing/node-name', 'base')
+
+        self.cancel_and_wait()
+        self.assert_no_active_block_jobs()
+
 class TestRelativePaths(ImageCommitTestCase):
     image_len = 1 * 1024 * 1024
     test_len = 1 * 1024 * 256

diff --git a/tests/qemu-iotests/040.out b/tests/qemu-iotests/040.out
index 6d9bee1a4b3cc501c6d6c3954d56289d4becb04a..e20a75ce4f199ef4d6bf46cd23a49f61e5eb8d6b 100644 (file)
--- a/tests/qemu-iotests/040.out
+++ b/tests/qemu-iotests/040.out
@@ -1,5 +1,5 @@
-...........................
+.............................
 ----------------------------------------------------------------------
-Ran 27 tests
+Ran 29 tests
 
 OK

diff --git a/tests/qemu-iotests/041 b/tests/qemu-iotests/041
index 2f5498643462440bfd3d4a8f922969c10e33120e..60f09cc1756965bbf096e614c7e764b921185bbd 100755 (executable)
--- a/tests/qemu-iotests/041
+++ b/tests/qemu-iotests/041
@@ -42,7 +42,7 @@ class TestSingleDrive(iotests.QMPTestCase):
     def setUp(self):
         iotests.create_image(backing_img, self.image_len)
         qemu_img('create', '-f', iotests.imgfmt, '-o', 'backing_file=%s' % backing_img, test_img)
-        self.vm = iotests.VM().add_drive(test_img)
+        self.vm = iotests.VM().add_drive(test_img, "node-name=top,backing.node-name=base")
         if iotests.qemu_default_machine == 'pc':
             self.vm.add_drive(None, 'media=cdrom', 'ide')
         self.vm.launch()
@@ -169,6 +169,42 @@ class TestSingleDrive(iotests.QMPTestCase):
         self.assertTrue(iotests.compare_images(test_img, target_img),
                         'target image does not match source after mirroring')
 
+    # Tests that the insertion of the mirror_top filter node doesn't make a
+    # difference to query-block
+    def test_implicit_node(self):
+        self.assert_no_active_block_jobs()
+
+        result = self.vm.qmp(self.qmp_cmd, device='drive0', sync='full',
+                             target=self.qmp_target)
+        self.assert_qmp(result, 'return', {})
+
+        result = self.vm.qmp('query-block')
+        self.assert_qmp(result, 'return[0]/inserted/file', test_img)
+        self.assert_qmp(result, 'return[0]/inserted/drv', iotests.imgfmt)
+        self.assert_qmp(result, 'return[0]/inserted/backing_file', backing_img)
+        self.assert_qmp(result, 'return[0]/inserted/backing_file_depth', 1)
+        self.assert_qmp(result, 'return[0]/inserted/image/filename', test_img)
+        self.assert_qmp(result, 'return[0]/inserted/image/backing-image/filename', backing_img)
+
+        result = self.vm.qmp('query-blockstats')
+        self.assert_qmp(result, 'return[0]/node-name', 'top')
+        self.assert_qmp(result, 'return[0]/backing/node-name', 'base')
+
+        self.cancel_and_wait(force=True)
+        result = self.vm.qmp('query-block')
+        self.assert_qmp(result, 'return[0]/inserted/file', test_img)
+        self.assert_qmp(result, 'return[0]/inserted/drv', iotests.imgfmt)
+        self.assert_qmp(result, 'return[0]/inserted/backing_file', backing_img)
+        self.assert_qmp(result, 'return[0]/inserted/backing_file_depth', 1)
+        self.assert_qmp(result, 'return[0]/inserted/image/filename', test_img)
+        self.assert_qmp(result, 'return[0]/inserted/image/backing-image/filename', backing_img)
+
+        result = self.vm.qmp('query-blockstats')
+        self.assert_qmp(result, 'return[0]/node-name', 'top')
+        self.assert_qmp(result, 'return[0]/backing/node-name', 'base')
+
+        self.vm.shutdown()
+
     def test_medium_not_found(self):
         if iotests.qemu_default_machine != 'pc':
             return

diff --git a/tests/qemu-iotests/041.out b/tests/qemu-iotests/041.out
index e30fd3b05bbbbfdb87a1bb54ea3669e5a052ad94..c28b392b87e4b604ea5130b9ed863f18da2d0e84 100644 (file)
--- a/tests/qemu-iotests/041.out
+++ b/tests/qemu-iotests/041.out
@@ -1,5 +1,5 @@
-...............................................................................
+.....................................................................................
 ----------------------------------------------------------------------
-Ran 79 tests
+Ran 85 tests
 
 OK