* [Qemu-devel] [PATCH v4 1/3] qapi: add x-debug-query-block-graph
2018-10-09 15:00 [Qemu-devel] [PATCH v4 0/3] block nodes graph visualization Vladimir Sementsov-Ogievskiy
@ 2018-10-09 15:00 ` Vladimir Sementsov-Ogievskiy
2018-10-13 13:55 ` Max Reitz
2018-10-09 15:00 ` [Qemu-devel] [PATCH v4 2/3] scripts: add render_block_graph function for QEMUMachine Vladimir Sementsov-Ogievskiy
2018-10-09 15:00 ` [Qemu-devel] [PATCH v4 3/3] not-for-commit: example of new command usage for debugging Vladimir Sementsov-Ogievskiy
2 siblings, 1 reply; 5+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2018-10-09 15:00 UTC (permalink / raw)
To: qemu-devel, qemu-block
Cc: crosa, ehabkost, eblake, armbru, mreitz, kwolf, vsementsov, den
Add a new command, returning block nodes (and their users) graph.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
qapi/block-core.json | 108 ++++++++++++++++++++++++
include/block/block.h | 1 +
include/sysemu/block-backend.h | 2 +
block.c | 146 +++++++++++++++++++++++++++++++++
block/block-backend.c | 5 ++
blockdev.c | 5 ++
6 files changed, 267 insertions(+)
diff --git a/qapi/block-core.json b/qapi/block-core.json
index cfb37f8c1d..1580bb95b8 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -1657,6 +1657,114 @@
##
{ 'command': 'query-named-block-nodes', 'returns': [ 'BlockDeviceInfo' ] }
+##
+# @BlockGraphNodeType:
+#
+# @block-backend: corresponds to BlockBackend
+#
+# @block-job: corresonds to BlockJob
+#
+# @block-driver: corresponds to BlockDriverState
+#
+# Since: 3.1
+##
+{ 'enum': 'BlockGraphNodeType',
+ 'data': [ 'block-backend', 'block-job', 'block-driver' ] }
+
+##
+# @BlockGraphNode:
+#
+# @id: Block graph node identifier. This @id is generated only for
+# x-debug-query-block-graph and does not relate to any other identifiers in
+# Qemu.
+#
+# @type: Type of graph node. Can be one of block-backend, block-job or
+# block-driver-state.
+#
+# @name: Human readable name of the node. Corresponds to node-name for
+# block-driver-state nodes; is not guaranteed to be unique in the whole
+# graph (with block-jobs and block-backends).
+#
+# Since: 3.1
+##
+{ 'struct': 'BlockGraphNode',
+ 'data': { 'id': 'uint64', 'type': 'BlockGraphNodeType', 'name': 'str' } }
+
+##
+# @BlockPermission:
+#
+# Enum of base block permissions.
+#
+# @consistent-read: A user that has the "permission" of consistent reads is
+# guaranteed that their view of the contents of the block
+# device is complete and self-consistent, representing the
+# contents of a disk at a specific point.
+# For most block devices (including their backing files) this
+# is true, but the property cannot be maintained in a few
+# situations like for intermediate nodes of a commit block
+# job.
+#
+# @write: This permission is required to change the visible disk contents.
+#
+# @write-unchanged: This permission (which is weaker than BLK_PERM_WRITE) is
+# both enough and required for writes to the block node when
+# the caller promises that the visible disk content doesn't
+# change.
+# As the BLK_PERM_WRITE permission is strictly stronger,
+# either is sufficient to perform an unchanging write.
+#
+# @resize: This permission is required to change the size of a block node.
+#
+# @graph-mod: This permission is required to change the node that this
+# BdrvChild points to.
+#
+# Since: 3.1
+##
+ { 'enum': 'BlockPermission',
+ 'data': [ 'consistent-read', 'write', 'write-unchanged', 'resize',
+ 'graph-mod' ] }
+##
+# @BlockGraphEdge:
+#
+# Block Graph edge description for x-debug-query-block-graph.
+#
+# @parent: parent id
+#
+# @child: child id
+#
+# @name: name of the relation (examples are 'file' and 'backing')
+#
+# @perm: granted permissions for the parent operating on the child
+#
+# @shared-perm: permissions that can still be granted to other users of the
+# child while it is still attached to this parent
+#
+# Since: 3.1
+##
+{ 'struct': 'BlockGraphEdge',
+ 'data': { 'parent': 'uint64', 'child': 'uint64',
+ 'name': 'str', 'perm': [ 'BlockPermission' ],
+ 'shared-perm': [ 'BlockPermission' ] } }
+
+##
+# @BlockGraph:
+#
+# Block Graph - list of nodes and list of edges.
+#
+# Since: 3.1
+##
+{ 'struct': 'BlockGraph',
+ 'data': { 'nodes': ['BlockGraphNode'], 'edges': ['BlockGraphEdge'] } }
+
+##
+# @x-debug-query-block-graph:
+#
+# Get the block graph.
+#
+# Since: 3.1
+##
+{ 'command': 'x-debug-query-block-graph', 'returns': 'BlockGraph' }
+
##
# @drive-mirror:
#
diff --git a/include/block/block.h b/include/block/block.h
index b189cf422e..31158cced0 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -445,6 +445,7 @@ void bdrv_eject(BlockDriverState *bs, bool eject_flag);
const char *bdrv_get_format_name(BlockDriverState *bs);
BlockDriverState *bdrv_find_node(const char *node_name);
BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp);
+BlockGraph *bdrv_get_block_graph(Error **errp);
BlockDriverState *bdrv_lookup_bs(const char *device,
const char *node_name,
Error **errp);
diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h
index 830d873f24..32ca5c1b12 100644
--- a/include/sysemu/block-backend.h
+++ b/include/sysemu/block-backend.h
@@ -237,4 +237,6 @@ int coroutine_fn blk_co_copy_range(BlockBackend *blk_in, int64_t off_in,
int bytes, BdrvRequestFlags read_flags,
BdrvRequestFlags write_flags);
+const BdrvChild *blk_root(BlockBackend *blk);
+
#endif
diff --git a/block.c b/block.c
index 7710b399a3..90825f427f 100644
--- a/block.c
+++ b/block.c
@@ -4047,6 +4047,152 @@ BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp)
return list;
}
+#define QAPI_LIST_ADD(list, element) do { \
+ typeof(list) _tmp = g_new(typeof(*(list)), 1); \
+ _tmp->value = (element); \
+ _tmp->next = (list); \
+ (list) = _tmp; \
+} while (0)
+
+typedef struct BlockGraphConstructor {
+ BlockGraph *graph;
+ GHashTable *graph_nodes;
+} BlockGraphConstructor;
+
+static BlockGraphConstructor *dbg_graph_new(void)
+{
+ BlockGraphConstructor *gr = g_new(BlockGraphConstructor, 1);
+
+ gr->graph = g_new0(BlockGraph, 1);
+ gr->graph_nodes = g_hash_table_new(NULL, NULL);
+
+ return gr;
+}
+
+static BlockGraph *dbg_graph_finalize(BlockGraphConstructor *gr)
+{
+ BlockGraph *graph = gr->graph;
+
+ g_hash_table_destroy(gr->graph_nodes);
+ g_free(gr);
+
+ return graph;
+}
+
+static uintptr_t dbg_graph_node_num(BlockGraphConstructor *gr, void *node)
+{
+ uintptr_t ret = (uintptr_t)g_hash_table_lookup(gr->graph_nodes, node);
+
+ if (ret != 0) {
+ return ret;
+ }
+
+ /* Start counting from 1, not 0, because 0 interferes with not-found (NULL)
+ * answer of g_hash_table_lookup.
+ */
+ ret = g_hash_table_size(gr->graph_nodes) + 1;
+ g_hash_table_insert(gr->graph_nodes, node, (void *)ret);
+
+ return ret;
+}
+
+static void dbg_graph_add_node(BlockGraphConstructor *gr, void *node,
+ BlockGraphNodeType type, const char *name)
+{
+ BlockGraphNode *n;
+
+ n = g_new0(BlockGraphNode, 1);
+
+ n->id = dbg_graph_node_num(gr, node);
+ n->type = type;
+ n->name = g_strdup(name);
+
+ QAPI_LIST_ADD(gr->graph->nodes, n);
+}
+
+static void dbg_graph_add_edge(BlockGraphConstructor *gr, void *parent,
+ const BdrvChild *child)
+{
+ typedef struct {
+ unsigned int flag;
+ BlockPermission num;
+ } PermissionMap;
+
+ static const PermissionMap permissions[] = {
+ { BLK_PERM_CONSISTENT_READ, BLOCK_PERMISSION_CONSISTENT_READ },
+ { BLK_PERM_WRITE, BLOCK_PERMISSION_WRITE },
+ { BLK_PERM_WRITE_UNCHANGED, BLOCK_PERMISSION_WRITE_UNCHANGED },
+ { BLK_PERM_RESIZE, BLOCK_PERMISSION_RESIZE },
+ { BLK_PERM_GRAPH_MOD, BLOCK_PERMISSION_GRAPH_MOD },
+ { 0, 0 }
+ };
+ const PermissionMap *p;
+ BlockGraphEdge *edge;
+
+ QEMU_BUILD_BUG_ON(1UL << (ARRAY_SIZE(permissions) - 1) != BLK_PERM_ALL + 1);
+
+ edge = g_new0(BlockGraphEdge, 1);
+
+ edge->parent = dbg_graph_node_num(gr, parent);
+ edge->child = dbg_graph_node_num(gr, child->bs);
+ edge->name = g_strdup(child->name);
+
+ for (p = permissions; p->flag; p++) {
+ if (p->flag & child->perm) {
+ QAPI_LIST_ADD(edge->perm, p->num);
+ }
+ if (p->flag & child->shared_perm) {
+ QAPI_LIST_ADD(edge->shared_perm, p->num);
+ }
+ }
+
+ QAPI_LIST_ADD(gr->graph->edges, edge);
+}
+
+
+BlockGraph *bdrv_get_block_graph(Error **errp)
+{
+ BlockBackend *blk;
+ BlockJob *job;
+ BlockDriverState *bs;
+ BdrvChild *child;
+ BlockGraphConstructor *gr = dbg_graph_new();
+
+ for (blk = blk_all_next(NULL); blk; blk = blk_all_next(blk)) {
+ char *allocated_name = NULL;
+ const char *name = blk_name(blk);
+
+ if (!name) {
+ name = allocated_name = blk_get_attached_dev_id(blk);
+ }
+ dbg_graph_add_node(gr, blk, BLOCK_GRAPH_NODE_TYPE_BLOCK_BACKEND, name);
+ g_free(allocated_name);
+ if (blk_root(blk)) {
+ dbg_graph_add_edge(gr, blk, blk_root(blk));
+ }
+ }
+
+ for (job = block_job_next(NULL); job; job = block_job_next(job)) {
+ GSList *el;
+
+ dbg_graph_add_node(gr, job, BLOCK_GRAPH_NODE_TYPE_BLOCK_JOB,
+ job->job.id);
+ for (el = job->nodes; el; el = el->next) {
+ dbg_graph_add_edge(gr, job, (BdrvChild *)el->data);
+ }
+ }
+
+ QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
+ dbg_graph_add_node(gr, bs, BLOCK_GRAPH_NODE_TYPE_BLOCK_DRIVER,
+ bs->node_name);
+ QLIST_FOREACH(child, &bs->children, next) {
+ dbg_graph_add_edge(gr, bs, child);
+ }
+ }
+
+ return dbg_graph_finalize(gr);
+}
+
BlockDriverState *bdrv_lookup_bs(const char *device,
const char *node_name,
Error **errp)
diff --git a/block/block-backend.c b/block/block-backend.c
index dc0cd57724..0146908229 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -2248,3 +2248,8 @@ int coroutine_fn blk_co_copy_range(BlockBackend *blk_in, int64_t off_in,
blk_out->root, off_out,
bytes, read_flags, write_flags);
}
+
+const BdrvChild *blk_root(BlockBackend *blk)
+{
+ return blk->root;
+}
diff --git a/blockdev.c b/blockdev.c
index a8755bd908..925db6cf92 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -3538,6 +3538,11 @@ BlockDeviceInfoList *qmp_query_named_block_nodes(Error **errp)
return bdrv_named_nodes_list(errp);
}
+BlockGraph *qmp_x_debug_query_block_graph(Error **errp)
+{
+ return bdrv_get_block_graph(errp);
+}
+
BlockJob *do_blockdev_backup(BlockdevBackup *backup, JobTxn *txn,
Error **errp)
{
--
2.18.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* [Qemu-devel] [PATCH v4 2/3] scripts: add render_block_graph function for QEMUMachine
2018-10-09 15:00 [Qemu-devel] [PATCH v4 0/3] block nodes graph visualization Vladimir Sementsov-Ogievskiy
2018-10-09 15:00 ` [Qemu-devel] [PATCH v4 1/3] qapi: add x-debug-query-block-graph Vladimir Sementsov-Ogievskiy
@ 2018-10-09 15:00 ` Vladimir Sementsov-Ogievskiy
2018-10-09 15:00 ` [Qemu-devel] [PATCH v4 3/3] not-for-commit: example of new command usage for debugging Vladimir Sementsov-Ogievskiy
2 siblings, 0 replies; 5+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2018-10-09 15:00 UTC (permalink / raw)
To: qemu-devel, qemu-block
Cc: crosa, ehabkost, eblake, armbru, mreitz, kwolf, vsementsov, den
Render block nodes graph with help of graphviz. This new function is
for debugging, so there is no sense to put it into qemu.py as a method
of QEMUMachine. Let's instead put it separately.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Acked-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
scripts/render_block_graph.py | 120 ++++++++++++++++++++++++++++++++++
1 file changed, 120 insertions(+)
create mode 100755 scripts/render_block_graph.py
diff --git a/scripts/render_block_graph.py b/scripts/render_block_graph.py
new file mode 100755
index 0000000000..ed7e581b4f
--- /dev/null
+++ b/scripts/render_block_graph.py
@@ -0,0 +1,120 @@
+#!/usr/bin/env python
+#
+# Render Qemu Block Graph
+#
+# Copyright (c) 2018 Virtuozzo International GmbH. All rights reserved.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+import os
+import sys
+import subprocess
+import json
+from graphviz import Digraph
+from qemu import MonitorResponseError
+
+
+def perm(arr):
+ s = 'w' if 'write' in arr else '_'
+ s += 'r' if 'consistent-read' in arr else '_'
+ s += 'u' if 'write-unchanged' in arr else '_'
+ s += 'g' if 'graph-mod' in arr else '_'
+ s += 's' if 'resize' in arr else '_'
+ return s
+
+
+def render_block_graph(qmp, filename, format='png'):
+ '''
+ Render graph in text (dot) representation into "@filename" and
+ representation in @format into "@filename.@format"
+ '''
+
+ bds_nodes = qmp.command('query-named-block-nodes')
+ bds_nodes = {n['node-name']: n for n in bds_nodes}
+
+ job_nodes = qmp.command('query-block-jobs')
+ job_nodes = {n['device']: n for n in job_nodes}
+
+ block_graph = qmp.command('x-debug-query-block-graph')
+
+ graph = Digraph(comment='Block Nodes Graph')
+ graph.format = format
+ graph.node('permission symbols:\l'
+ ' w - Write\l'
+ ' r - consistent-Read\l'
+ ' u - write - Unchanged\l'
+ ' g - Graph-mod\l'
+ ' s - reSize\l'
+ 'edge label scheme:\l'
+ ' <child type>\l'
+ ' <perm>\l'
+ ' <shared_perm>\l', shape='none')
+
+ for n in block_graph['nodes']:
+ if n['type'] == 'block-driver':
+ info = bds_nodes[n['name']]
+ label = n['name'] + ' [' + info['drv'] + ']'
+ if info['drv'] == 'file':
+ label += '\n' + os.path.basename(info['file'])
+ shape = 'ellipse'
+ elif n['type'] == 'block-job':
+ info = job_nodes[n['name']]
+ label = info['type'] + ' job (' + n['name'] + ')'
+ shape = 'box'
+ else:
+ assert n['type'] == 'block-backend'
+ label = n['name'] if n['name'] else 'unnamed blk'
+ shape = 'box'
+
+ graph.node(str(n['id']), label, shape=shape)
+
+ for e in block_graph['edges']:
+ label = '%s\l%s\l%s\l' % (e['name'], perm(e['perm']),
+ perm(e['shared-perm']))
+ graph.edge(str(e['parent']), str(e['child']), label=label)
+
+ graph.render(filename)
+
+
+class LibvirtGuest():
+ def __init__(self, name):
+ self.name = name
+
+ def command(self, cmd):
+ # only supports qmp commands without parameters
+ m = {'execute': cmd}
+ ar = ['virsh', 'qemu-monitor-command', self.name, json.dumps(m)]
+
+ reply = json.loads(subprocess.check_output(ar))
+
+ if 'error' in reply:
+ raise MonitorResponseError(reply)
+
+ return reply['return']
+
+
+if __name__ == '__main__':
+ obj = sys.argv[1]
+ out = sys.argv[2]
+
+ if os.path.exists(obj):
+ # assume unix socket
+ qmp = QEMUMonitorProtocol(obj)
+ qmp.connect()
+ else:
+ # assume libvirt guest name
+ qmp = LibvirtGuest(obj)
+
+ render_block_graph(qmp, out)
--
2.18.0
^ permalink raw reply related [flat|nested] 5+ messages in thread