blockdev: Keep track of monitor-owned BDS

As a side effect, we can now make x-blockdev-del's check whether a BDS
is actually owned by the monitor explicit.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

blockdev.c

@@ -50,6 +50,9 @@
 #include "trace.h"
 #include "sysemu/arch_init.h"
 
+static QTAILQ_HEAD(, BlockDriverState) monitor_bdrv_states =
+    QTAILQ_HEAD_INITIALIZER(monitor_bdrv_states);
+
 static const char *const if_name[IF_COUNT] = {
     [IF_NONE] = "none",
     [IF_IDE] = "ide",
@@ -702,6 +705,19 @@ static BlockDriverState *bds_tree_init(QDict *bs_opts, Error **errp)
     return NULL;
 }
 
+void blockdev_close_all_bdrv_states(void)
+{
+    BlockDriverState *bs, *next_bs;
+
+    QTAILQ_FOREACH_SAFE(bs, &monitor_bdrv_states, monitor_list, next_bs) {
+        AioContext *ctx = bdrv_get_aio_context(bs);
+
+        aio_context_acquire(ctx);
+        bdrv_unref(bs);
+        aio_context_release(ctx);
+    }
+}
+
 static void qemu_opt_rename(QemuOpts *opts, const char *from, const char *to,
                             Error **errp)
 {
@@ -3875,12 +3891,15 @@ void qmp_blockdev_add(BlockdevOptions *options, Error **errp)
         if (!bs) {
             goto fail;
         }
+
+        QTAILQ_INSERT_TAIL(&monitor_bdrv_states, bs, monitor_list);
     }
 
     if (bs && bdrv_key_required(bs)) {
         if (blk) {
             blk_unref(blk);
         } else {
+            QTAILQ_REMOVE(&monitor_bdrv_states, bs, monitor_list);
             bdrv_unref(bs);
         }
         error_setg(errp, "blockdev-add doesn't support encrypted devices");
@@ -3940,7 +3959,13 @@ void qmp_x_blockdev_del(bool has_id, const char *id,
             goto out;
         }
 
-        if (bs->refcnt > 1 || !QLIST_EMPTY(&bs->parents)) {
+        if (!blk && !bs->monitor_list.tqe_prev) {
+            error_setg(errp, "Node %s is not owned by the monitor",
+                       bs->node_name);
+            goto out;
+        }
+
+        if (bs->refcnt > 1) {
             error_setg(errp, "Block device %s is in use",
                        bdrv_get_device_or_node_name(bs));
             goto out;
@@ -3950,6 +3975,7 @@ void qmp_x_blockdev_del(bool has_id, const char *id,
     if (blk) {
         blk_unref(blk);
     } else {
+        QTAILQ_REMOVE(&monitor_bdrv_states, bs, monitor_list);
         bdrv_unref(bs);
     }
 

include/block/block_int.h

@@ -445,6 +445,8 @@ struct BlockDriverState {
     QTAILQ_ENTRY(BlockDriverState) device_list;
     /* element of the list of all BlockDriverStates (all_bdrv_states) */
     QTAILQ_ENTRY(BlockDriverState) bs_list;
+    /* element of the list of monitor-owned BDS */
+    QTAILQ_ENTRY(BlockDriverState) monitor_list;
     QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps;
     int refcnt;
 
@@ -707,4 +709,6 @@ bool bdrv_requests_pending(BlockDriverState *bs);
 void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out);
 void bdrv_undo_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap *in);
 
+void blockdev_close_all_bdrv_states(void);
+
 #endif /* BLOCK_INT_H */

stubs/Makefile.objs

@@ -1,5 +1,6 @@
 stub-obj-y += arch-query-cpu-def.o
 stub-obj-y += bdrv-commit-all.o
+stub-obj-y += blockdev-close-all-bdrv-states.o
 stub-obj-y += clock-warp.o
 stub-obj-y += cpu-get-clock.o
 stub-obj-y += cpu-get-icount.o

stubs/blockdev-close-all-bdrv-states.c

@@ -0,0 +1,5 @@
+#include "block/block_int.h"
+
+void blockdev_close_all_bdrv_states(void)
+{
+}