From 9c4218e957331e1ba0ba7565730b0b71c49b8d70 Mon Sep 17 00:00:00 2001
From: Max Reitz <mreitz@redhat.com>
Date: Fri, 29 Jan 2016 16:36:12 +0100
Subject: 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                             | 28 +++++++++++++++++++++++++++-
 include/block/block_int.h              |  4 ++++
 stubs/Makefile.objs                    |  1 +
 stubs/blockdev-close-all-bdrv-states.c |  5 +++++
 4 files changed, 37 insertions(+), 1 deletion(-)
 create mode 100644 stubs/blockdev-close-all-bdrv-states.c

diff --git a/blockdev.c b/blockdev.c
index 09d4621cd2..35e1e5c58f 100644
--- a/blockdev.c
+++ b/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 @@ fail:
     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);
     }
 
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 1e4c51875e..dd00d12a6f 100644
--- a/include/block/block_int.h
+++ b/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 */
diff --git a/stubs/Makefile.objs b/stubs/Makefile.objs
index d7898a0c4a..e922de982f 100644
--- a/stubs/Makefile.objs
+++ b/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
diff --git a/stubs/blockdev-close-all-bdrv-states.c b/stubs/blockdev-close-all-bdrv-states.c
new file mode 100644
index 0000000000..12d2442362
--- /dev/null
+++ b/stubs/blockdev-close-all-bdrv-states.c
@@ -0,0 +1,5 @@
+#include "block/block_int.h"
+
+void blockdev_close_all_bdrv_states(void)
+{
+}
-- 
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