[Qemu-devel] [PATCH 13/14] Add flag to indicate external users to block device

[Kevin Wolf <kwolf@redhat.com>]

From: Marcelo Tosatti <mtosatti@redhat.com>

Certain operations such as drive_del or resize cannot be performed
while external users (eg. block migration) reference the block device.

Add a flag to indicate that.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block.c     |   11 +++++++++++
 block.h     |    2 ++
 block_int.h |    1 +
 3 files changed, 14 insertions(+), 0 deletions(-)

diff --git a/block.c b/block.c
index 998df1b..ee9edfc 100644
--- a/block.c
+++ b/block.c
@@ -2774,6 +2774,17 @@ int64_t bdrv_get_dirty_count(BlockDriverState *bs)
     return bs->dirty_count;
 }
 
+void bdrv_set_in_use(BlockDriverState *bs, int in_use)
+{
+    assert(bs->in_use != in_use);
+    bs->in_use = in_use;
+}
+
+int bdrv_in_use(BlockDriverState *bs)
+{
+    return bs->in_use;
+}
+
 int bdrv_img_create(const char *filename, const char *fmt,
                     const char *base_filename, const char *base_fmt,
                     char *options, uint64_t img_size, int flags)
diff --git a/block.h b/block.h
index 239f729..19f4768 100644
--- a/block.h
+++ b/block.h
@@ -241,6 +241,8 @@ void bdrv_reset_dirty(BlockDriverState *bs, int64_t cur_sector,
                       int nr_sectors);
 int64_t bdrv_get_dirty_count(BlockDriverState *bs);
 
+void bdrv_set_in_use(BlockDriverState *bs, int in_use);
+int bdrv_in_use(BlockDriverState *bs);
 
 typedef enum {
     BLKDBG_L1_UPDATE,
diff --git a/block_int.h b/block_int.h
index 6ebdc3e..545ad11 100644
--- a/block_int.h
+++ b/block_int.h
@@ -199,6 +199,7 @@ struct BlockDriverState {
     char device_name[32];
     unsigned long *dirty_bitmap;
     int64_t dirty_count;
+    int in_use; /* users other than guest access, eg. block migration */
     QTAILQ_ENTRY(BlockDriverState) list;
     void *private;
 };
-- 
1.7.2.3