Commit 9fcb0251 authored by Fam Zheng's avatar Fam Zheng Committed by Stefan Hajnoczi
Browse files

block: implement reference count for BlockDriverState 



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: default avatarFam Zheng <famz@redhat.com>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent 13c91cb7

block.c

+21 −0
Original line number Diff line number Diff line
@@ -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);

include/block/block.h

+2 −0
Original line number Diff line number Diff line
@@ -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);

include/block/block_int.h

+1 −0
Original line number Diff line number Diff line
@@ -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;