From 5d3b4e99463642b226d1a37433d0e4b376162468 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Fri, 21 Dec 2018 20:09:07 +0300 Subject: [PATCH] qapi: add x-debug-query-block-graph Add a new command, returning block nodes (and their users) graph. Signed-off-by: Vladimir Sementsov-Ogievskiy Message-id: 20181221170909.25584-2-vsementsov@virtuozzo.com Signed-off-by: Max Reitz --- block.c | 148 +++++++++++++++++++++++++++++++++ block/block-backend.c | 5 ++ blockdev.c | 5 ++ include/block/block.h | 1 + include/sysemu/block-backend.h | 2 + qapi/block-core.json | 108 ++++++++++++++++++++++++ 6 files changed, 269 insertions(+) diff --git a/block.c b/block.c index 4f5ff2cc12..e795a7c5de 100644 --- a/block.c +++ b/block.c @@ -4119,6 +4119,154 @@ 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 XDbgBlockGraphConstructor { + XDbgBlockGraph *graph; + GHashTable *graph_nodes; +} XDbgBlockGraphConstructor; + +static XDbgBlockGraphConstructor *xdbg_graph_new(void) +{ + XDbgBlockGraphConstructor *gr = g_new(XDbgBlockGraphConstructor, 1); + + gr->graph = g_new0(XDbgBlockGraph, 1); + gr->graph_nodes = g_hash_table_new(NULL, NULL); + + return gr; +} + +static XDbgBlockGraph *xdbg_graph_finalize(XDbgBlockGraphConstructor *gr) +{ + XDbgBlockGraph *graph = gr->graph; + + g_hash_table_destroy(gr->graph_nodes); + g_free(gr); + + return graph; +} + +static uintptr_t xdbg_graph_node_num(XDbgBlockGraphConstructor *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 xdbg_graph_add_node(XDbgBlockGraphConstructor *gr, void *node, + XDbgBlockGraphNodeType type, const char *name) +{ + XDbgBlockGraphNode *n; + + n = g_new0(XDbgBlockGraphNode, 1); + + n->id = xdbg_graph_node_num(gr, node); + n->type = type; + n->name = g_strdup(name); + + QAPI_LIST_ADD(gr->graph->nodes, n); +} + +static void xdbg_graph_add_edge(XDbgBlockGraphConstructor *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; + XDbgBlockGraphEdge *edge; + + QEMU_BUILD_BUG_ON(1UL << (ARRAY_SIZE(permissions) - 1) != BLK_PERM_ALL + 1); + + edge = g_new0(XDbgBlockGraphEdge, 1); + + edge->parent = xdbg_graph_node_num(gr, parent); + edge->child = xdbg_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); +} + + +XDbgBlockGraph *bdrv_get_xdbg_block_graph(Error **errp) +{ + BlockBackend *blk; + BlockJob *job; + BlockDriverState *bs; + BdrvChild *child; + XDbgBlockGraphConstructor *gr = xdbg_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); + } + xdbg_graph_add_node(gr, blk, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_BACKEND, + name); + g_free(allocated_name); + if (blk_root(blk)) { + xdbg_graph_add_edge(gr, blk, blk_root(blk)); + } + } + + for (job = block_job_next(NULL); job; job = block_job_next(job)) { + GSList *el; + + xdbg_graph_add_node(gr, job, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_JOB, + job->job.id); + for (el = job->nodes; el; el = el->next) { + xdbg_graph_add_edge(gr, job, (BdrvChild *)el->data); + } + } + + QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) { + xdbg_graph_add_node(gr, bs, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_DRIVER, + bs->node_name); + QLIST_FOREACH(child, &bs->children, next) { + xdbg_graph_add_edge(gr, bs, child); + } + } + + return xdbg_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 60d37a0c3d..cf05abd89d 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -2249,3 +2249,8 @@ 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 a8fa8748a9..fb18e9c975 100644 --- a/blockdev.c +++ b/blockdev.c @@ -3582,6 +3582,11 @@ BlockDeviceInfoList *qmp_query_named_block_nodes(Error **errp) return bdrv_named_nodes_list(errp); } +XDbgBlockGraph *qmp_x_debug_query_block_graph(Error **errp) +{ + return bdrv_get_xdbg_block_graph(errp); +} + BlockJob *do_blockdev_backup(BlockdevBackup *backup, JobTxn *txn, Error **errp) { diff --git a/include/block/block.h b/include/block/block.h index f70a843b72..57233cf2c0 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -448,6 +448,7 @@ 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); +XDbgBlockGraph *bdrv_get_xdbg_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 c96bcdee14..c8f816a200 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/qapi/block-core.json b/qapi/block-core.json index 91685be6c2..cde1b53708 100644 --- a/qapi/block-core.json +++ b/qapi/block-core.json @@ -1665,6 +1665,114 @@ ## { 'command': 'query-named-block-nodes', 'returns': [ 'BlockDeviceInfo' ] } +## +# @XDbgBlockGraphNodeType: +# +# @block-backend: corresponds to BlockBackend +# +# @block-job: corresonds to BlockJob +# +# @block-driver: corresponds to BlockDriverState +# +# Since: 4.0 +## +{ 'enum': 'XDbgBlockGraphNodeType', + 'data': [ 'block-backend', 'block-job', 'block-driver' ] } + +## +# @XDbgBlockGraphNode: +# +# @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: 4.0 +## +{ 'struct': 'XDbgBlockGraphNode', + 'data': { 'id': 'uint64', 'type': 'XDbgBlockGraphNodeType', '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: 4.0 +## + { 'enum': 'BlockPermission', + 'data': [ 'consistent-read', 'write', 'write-unchanged', 'resize', + 'graph-mod' ] } +## +# @XDbgBlockGraphEdge: +# +# 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: 4.0 +## +{ 'struct': 'XDbgBlockGraphEdge', + 'data': { 'parent': 'uint64', 'child': 'uint64', + 'name': 'str', 'perm': [ 'BlockPermission' ], + 'shared-perm': [ 'BlockPermission' ] } } + +## +# @XDbgBlockGraph: +# +# Block Graph - list of nodes and list of edges. +# +# Since: 4.0 +## +{ 'struct': 'XDbgBlockGraph', + 'data': { 'nodes': ['XDbgBlockGraphNode'], 'edges': ['XDbgBlockGraphEdge'] } } + +## +# @x-debug-query-block-graph: +# +# Get the block graph. +# +# Since: 4.0 +## +{ 'command': 'x-debug-query-block-graph', 'returns': 'XDbgBlockGraph' } + ## # @drive-mirror: # -- GitLab