This makes use of op_blocker and blocks all the operations except for
commit target, on each BlockDriverState->backing_hd.
The asserts for op_blocker in bdrv_swap are removed because with this
change, the target of block commit has at least the backing blocker of
its child, so the assertion is not true. Callers should do their check.
Signed-off-by: Fam Zheng <f...@redhat.com>
---
block.c | 24 ++++++++++++++++++++----
block/mirror.c | 1 +
include/block/block_int.h | 3 +++
3 files changed, 24 insertions(+), 4 deletions(-)
diff --git a/block.c b/block.c
index 7859340..6f803fa 100644
--- a/block.c
+++ b/block.c
@@ -1055,14 +1055,31 @@ fail:
void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd)
{
+ if (bs->backing_hd) {
+ assert(error_is_set(&bs->backing_blocker));
+ bdrv_op_unblock_all(bs->backing_hd, bs->backing_blocker);
+ } else if (backing_hd) {
+ error_setg(&bs->backing_blocker,
+ "device is used as backing hd of '%s'",
+ bs->device_name);
+ }
+
bs->backing_hd = backing_hd;
if (!backing_hd) {
+ if (error_is_set(&bs->backing_blocker)) {
+ error_free(bs->backing_blocker);
+ }
goto out;
}
bs->open_flags &= ~BDRV_O_NO_BACKING;
pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_hd->filename);
pstrcpy(bs->backing_format, sizeof(bs->backing_format),
backing_hd->drv ? backing_hd->drv->format_name : "");
+
+ bdrv_op_block_all(bs->backing_hd, bs->backing_blocker);
+ /* Otherwise we won't be able to commit due to check in bdrv_commit */
+ bdrv_op_unblock(bs->backing_hd, BLOCK_OP_TYPE_COMMIT,
+ bs->backing_blocker);
out:
bdrv_refresh_limits(bs);
}
@@ -1717,8 +1734,9 @@ void bdrv_close(BlockDriverState *bs)
if (bs->drv) {
if (bs->backing_hd) {
- bdrv_unref(bs->backing_hd);
- bs->backing_hd = NULL;
+ BlockDriverState *backing_hd = bs->backing_hd;
+ bdrv_set_backing_hd(bs, NULL);
+ bdrv_unref(backing_hd);
}
bs->drv->bdrv_close(bs);
g_free(bs->opaque);
@@ -1926,7 +1944,6 @@ void bdrv_swap(BlockDriverState *bs_new, BlockDriverState
*bs_old)
assert(QLIST_EMPTY(&bs_new->dirty_bitmaps));
assert(bs_new->job == NULL);
assert(bs_new->dev == NULL);
- assert(bdrv_op_blocker_is_empty(bs_new));
assert(bs_new->io_limits_enabled == false);
assert(!throttle_have_timer(&bs_new->throttle_state));
@@ -1945,7 +1962,6 @@ void bdrv_swap(BlockDriverState *bs_new, BlockDriverState
*bs_old)
/* Check a few fields that should remain attached to the device */
assert(bs_new->dev == NULL);
assert(bs_new->job == NULL);
- assert(bdrv_op_blocker_is_empty(bs_new));
assert(bs_new->io_limits_enabled == false);
assert(!throttle_have_timer(&bs_new->throttle_state));
diff --git a/block/mirror.c b/block/mirror.c
index 0ef41f9..22ec5be 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -496,6 +496,7 @@ immediate_exit:
* trigger the unref from the top one */
BlockDriverState *p = s->base->backing_hd;
s->base->backing_hd = NULL;
+ bdrv_op_unblock_all(p, s->base->backing_blocker);
bdrv_unref(p);
}
}
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 025ee02..594df74 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -369,6 +369,9 @@ struct BlockDriverState {
BlockJob *job;
QDict *options;
+
+ /* The error object in use for blocking operations on backing_hd */
+ Error *backing_blocker;
};
int get_tmp_filename(char *filename, int size);
--
1.9.1
