[openSUSE] block: Convert qmp_query_block() to coroutine_fn (bsc#1211000)

This is another caller of bdrv_get_allocated_file_size() that needs to
be converted to a coroutine because that function will be made
asynchronous when called (indirectly) from the QMP dispatcher.

This QMP command is a candidate because it calls bdrv_do_query_node_info(),
which in turn calls bdrv_get_allocated_file_size().

We've determined bdrv_do_query_node_info() to be coroutine-safe (see
previous commits), so we can just put this QMP command in a coroutine.

Since qmp_query_block() now expects to run in a coroutine, its callers
need to be converted as well. Convert hmp_info_block(), which calls
only coroutine-safe code, including qmp_query_named_block_nodes()
which has been converted to coroutine in the previous patches.

Now that all callers of bdrv_[co_]block_device_info() are using the
coroutine version, a few things happen:

 - we can return to using bdrv_block_device_info() without a wrapper;

 - bdrv_get_allocated_file_size() can stop being mixed;

 - bdrv_co_get_allocated_file_size() needs to be put under the graph
   lock because it is being called wthout the wrapper;

 - bdrv_do_query_node_info() doesn't need to acquire the AioContext
   because it doesn't call aio_poll anymore;

Signed-off-by: Fabiano Rosas <farosas@suse.de>
References: bsc#1211000
[relax main loop requirement at qmp_query_block]
Signed-off-by: Fabiano Rosas <farosas@suse.de>

block.c

@@ -6348,7 +6348,7 @@ BlockDeviceInfoList *bdrv_named_nodes_list(bool flat,
 
     list = NULL;
     QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
-        BlockDeviceInfo *info = bdrv_co_block_device_info(NULL, bs, flat, errp);
+        BlockDeviceInfo *info = bdrv_block_device_info(NULL, bs, flat, errp);
         if (!info) {
             qapi_free_BlockDeviceInfoList(list);
             return NULL;

block/monitor/block-hmp-cmds.c

@@ -748,7 +748,7 @@ static void print_block_info(Monitor *mon, BlockInfo *info,
     }
 }
 
-void hmp_info_block(Monitor *mon, const QDict *qdict)
+void coroutine_fn hmp_info_block(Monitor *mon, const QDict *qdict)
 {
     BlockInfoList *block_list, *info;
     BlockDeviceInfoList *blockdev_list, *blockdev;

block/qapi.c

@@ -41,7 +41,7 @@
 #include "qemu/qemu-print.h"
 #include "sysemu/block-backend.h"
 
-BlockDeviceInfo *coroutine_fn bdrv_co_block_device_info(BlockBackend *blk,
+BlockDeviceInfo *coroutine_fn bdrv_block_device_info(BlockBackend *blk,
                                                      BlockDriverState *bs,
                                                      bool flat,
                                                      Error **errp)
@@ -234,8 +234,6 @@ bdrv_do_query_node_info(BlockDriverState *bs, BlockNodeInfo *info, Error **errp)
     int ret;
     Error *err = NULL;
 
-    aio_context_acquire(bdrv_get_aio_context(bs));
-
     size = bdrv_getlength(bs);
     if (size < 0) {
         error_setg_errno(errp, -size, "Can't get image size '%s'",
@@ -248,7 +246,9 @@ bdrv_do_query_node_info(BlockDriverState *bs, BlockNodeInfo *info, Error **errp)
     info->filename        = g_strdup(bs->filename);
     info->format          = g_strdup(bdrv_get_format_name(bs));
     info->virtual_size    = size;
-    info->actual_size     = bdrv_get_allocated_file_size(bs);
+    bdrv_graph_co_rdlock();
+    info->actual_size     = bdrv_co_get_allocated_file_size(bs);
+    bdrv_graph_co_rdunlock();
     info->has_actual_size = info->actual_size >= 0;
     if (bs->encrypted) {
         info->encrypted = true;
@@ -304,7 +304,7 @@ bdrv_do_query_node_info(BlockDriverState *bs, BlockNodeInfo *info, Error **errp)
     }
 
 out:
-    aio_context_release(bdrv_get_aio_context(bs));
+    return;
 }
 
 /**
@@ -667,13 +667,13 @@ bdrv_query_bds_stats(BlockDriverState *bs, bool blk_level)
     return s;
 }
 
-BlockInfoList *qmp_query_block(Error **errp)
+BlockInfoList *coroutine_fn qmp_query_block(Error **errp)
 {
     BlockInfoList *head = NULL, **p_next = &head;
     BlockBackend *blk;
     Error *local_err = NULL;
 
-    GRAPH_RDLOCK_GUARD_MAINLOOP();
+    GRAPH_RDLOCK_GUARD();
 
     for (blk = blk_all_next(NULL); blk; blk = blk_all_next(blk)) {
         BlockInfoList *info;

hmp-commands-info.hx

@@ -65,6 +65,7 @@ ERST
         .help       = "show info of one block device or all block devices "
                       "(-n: show named nodes; -v: show details)",
         .cmd        = hmp_info_block,
+        .coroutine  = true,
     },
 
 SRST

include/block/block-hmp-cmds.h

@@ -48,7 +48,7 @@ void hmp_eject(Monitor *mon, const QDict *qdict);
 
 void hmp_qemu_io(Monitor *mon, const QDict *qdict);
 
-void hmp_info_block(Monitor *mon, const QDict *qdict);
+void coroutine_fn hmp_info_block(Monitor *mon, const QDict *qdict);
 void hmp_info_blockstats(Monitor *mon, const QDict *qdict);
 void hmp_info_block_jobs(Monitor *mon, const QDict *qdict);
 void hmp_info_snapshots(Monitor *mon, const QDict *qdict);

include/block/block-io.h

@@ -87,7 +87,7 @@ int64_t co_wrapper_mixed_bdrv_rdlock bdrv_getlength(BlockDriverState *bs);
 int64_t coroutine_fn GRAPH_RDLOCK
 bdrv_co_get_allocated_file_size(BlockDriverState *bs);
 
-int64_t co_wrapper_mixed_bdrv_rdlock
+int64_t co_wrapper_bdrv_rdlock
 bdrv_get_allocated_file_size(BlockDriverState *bs);
 
 BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts *opts,

include/block/qapi.h

@@ -30,10 +30,7 @@
 #include "block/snapshot.h"
 #include "qapi/qapi-types-block-core.h"
 
-BlockDeviceInfo * coroutine_fn GRAPH_RDLOCK
-bdrv_co_block_device_info(BlockBackend *blk, BlockDriverState *bs,
-                          bool flat, Error **errp);
-BlockDeviceInfo *co_wrapper_bdrv_rdlock
+BlockDeviceInfo *coroutine_fn GRAPH_RDLOCK
 bdrv_block_device_info(BlockBackend *blk, BlockDriverState *bs, bool flat,
                        Error **errp);
 int GRAPH_RDLOCK

qapi/block-core.json

@@ -839,7 +839,7 @@
 #    }
 ##
 { 'command': 'query-block', 'returns': ['BlockInfo'],
-  'allow-preconfig': true }
+  'allow-preconfig': true, 'coroutine': true }
 
 ##
 # @BlockDeviceTimedStats: