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[Qemu-devel] [PULL 12/42] block: implement reference count for BlockDriv
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PULL 12/42] block: implement reference count for BlockDriverState |
Date: |
Fri, 6 Sep 2013 17:38:43 +0200 |
From: Fam Zheng <address@hidden>
Introduce bdrv_ref/bdrv_unref to manage the lifecycle of
BlockDriverState. They are unused for now but will used to replace
bdrv_delete() later.
Signed-off-by: Fam Zheng <address@hidden>
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
block.c | 21 +++++++++++++++++++++
include/block/block.h | 2 ++
include/block/block_int.h | 1 +
3 files changed, 24 insertions(+)
diff --git a/block.c b/block.c
index 0292d1d..a2b6003 100644
--- a/block.c
+++ b/block.c
@@ -332,6 +332,7 @@ BlockDriverState *bdrv_new(const char *device_name)
notifier_with_return_list_init(&bs->before_write_notifiers);
qemu_co_queue_init(&bs->throttled_reqs[0]);
qemu_co_queue_init(&bs->throttled_reqs[1]);
+ bs->refcnt = 1;
return bs;
}
@@ -1566,6 +1567,9 @@ static void bdrv_move_feature_fields(BlockDriverState
*bs_dest,
/* dirty bitmap */
bs_dest->dirty_bitmap = bs_src->dirty_bitmap;
+ /* reference count */
+ bs_dest->refcnt = bs_src->refcnt;
+
/* job */
bs_dest->in_use = bs_src->in_use;
bs_dest->job = bs_src->job;
@@ -4297,6 +4301,23 @@ int64_t bdrv_get_dirty_count(BlockDriverState *bs)
}
}
+/* Get a reference to bs */
+void bdrv_ref(BlockDriverState *bs)
+{
+ bs->refcnt++;
+}
+
+/* Release a previously grabbed reference to bs.
+ * If after releasing, reference count is zero, the BlockDriverState is
+ * deleted. */
+void bdrv_unref(BlockDriverState *bs)
+{
+ assert(bs->refcnt > 0);
+ if (--bs->refcnt == 0) {
+ bdrv_delete(bs);
+ }
+}
+
void bdrv_set_in_use(BlockDriverState *bs, int in_use)
{
assert(bs->in_use != in_use);
diff --git a/include/block/block.h b/include/block/block.h
index 6207ff2..f24e1ff 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -355,6 +355,8 @@ int64_t bdrv_get_dirty_count(BlockDriverState *bs);
void bdrv_enable_copy_on_read(BlockDriverState *bs);
void bdrv_disable_copy_on_read(BlockDriverState *bs);
+void bdrv_ref(BlockDriverState *bs);
+void bdrv_unref(BlockDriverState *bs);
void bdrv_set_in_use(BlockDriverState *bs, int in_use);
int bdrv_in_use(BlockDriverState *bs);
diff --git a/include/block/block_int.h b/include/block/block_int.h
index c3c9c61..b9212b8 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -277,6 +277,7 @@ struct BlockDriverState {
BlockDeviceIoStatus iostatus;
char device_name[32];
HBitmap *dirty_bitmap;
+ int refcnt;
int in_use; /* users other than guest access, eg. block migration */
QTAILQ_ENTRY(BlockDriverState) list;
--
1.8.3.1
- [Qemu-devel] [PULL 03/42] block: Enable the new throttling code in the block layer., (continued)
- [Qemu-devel] [PULL 03/42] block: Enable the new throttling code in the block layer., Stefan Hajnoczi, 2013/09/06
- [Qemu-devel] [PULL 02/42] throttle: Add units tests, Stefan Hajnoczi, 2013/09/06
- [Qemu-devel] [PULL 04/42] block: Add support for throttling burst max in QMP and the command line., Stefan Hajnoczi, 2013/09/06
- [Qemu-devel] [PULL 05/42] block: Add iops_size to do the iops accounting for a given io size., Stefan Hajnoczi, 2013/09/06
- [Qemu-devel] [PULL 06/42] qemu-iotests: Adjust test result 039, Stefan Hajnoczi, 2013/09/06
- [Qemu-devel] [PULL 08/42] w32: Fix access to host devices (regression), Stefan Hajnoczi, 2013/09/06
- [Qemu-devel] [PULL 07/42] add qemu-img convert -n option (skip target volume creation), Stefan Hajnoczi, 2013/09/06
- [Qemu-devel] [PULL 10/42] vvfat: use bdrv_new() to allocate BlockDriverState, Stefan Hajnoczi, 2013/09/06
- [Qemu-devel] [PULL 09/42] aio / timers: fix build of test/test-aio.c on non-linux platforms, Stefan Hajnoczi, 2013/09/06
- [Qemu-devel] [PULL 11/42] iscsi: use bdrv_new() instead of stack structure, Stefan Hajnoczi, 2013/09/06
- [Qemu-devel] [PULL 12/42] block: implement reference count for BlockDriverState,
Stefan Hajnoczi <=
- [Qemu-devel] [PULL 13/42] block: make bdrv_delete() static, Stefan Hajnoczi, 2013/09/06
- [Qemu-devel] [PULL 14/42] migration: omit drive ref as we have bdrv_ref now, Stefan Hajnoczi, 2013/09/06
- [Qemu-devel] [PULL 15/42] xen_disk: simplify blk_disconnect with refcnt, Stefan Hajnoczi, 2013/09/06
- [Qemu-devel] [PULL 27/42] qemu-img: always probe the input image for allocated sectors, Stefan Hajnoczi, 2013/09/06
- [Qemu-devel] [PULL 28/42] block: make bdrv_has_zero_init return false for copy-on-write-images, Stefan Hajnoczi, 2013/09/06
- [Qemu-devel] [PULL 29/42] block: introduce bdrv_get_block_status API, Stefan Hajnoczi, 2013/09/06
- [Qemu-devel] [PULL 31/42] block: return get_block_status data and flags for formats, Stefan Hajnoczi, 2013/09/06
- [Qemu-devel] [PULL 30/42] block: define get_block_status return value, Stefan Hajnoczi, 2013/09/06