From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60479) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WnrcT-0005lw-5x for qemu-devel@nongnu.org; Fri, 23 May 2014 11:43:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WnrcK-0006Gm-EX for qemu-devel@nongnu.org; Fri, 23 May 2014 11:42:53 -0400 Received: from mx1.redhat.com ([209.132.183.28]:9060) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WnrcK-0006Gc-6P for qemu-devel@nongnu.org; Fri, 23 May 2014 11:42:44 -0400 From: Stefan Hajnoczi Date: Fri, 23 May 2014 17:41:44 +0200 Message-Id: <1400859725-31879-13-git-send-email-stefanha@redhat.com> In-Reply-To: <1400859725-31879-1-git-send-email-stefanha@redhat.com> References: <1400859725-31879-1-git-send-email-stefanha@redhat.com> Subject: [Qemu-devel] [PULL 12/33] block: Add backing_blocker in BlockDriverState List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Peter Maydell , Fam Zheng , Stefan Hajnoczi From: Fam Zheng 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 Signed-off-by: Stefan Hajnoczi --- block.c | 23 +++++++++++++++++++---- block/mirror.c | 2 +- include/block/block_int.h | 3 +++ 3 files changed, 23 insertions(+), 5 deletions(-) diff --git a/block.c b/block.c index 1271dd2..aa9b5ab 100644 --- a/block.c +++ b/block.c @@ -1097,14 +1097,30 @@ fail: void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd) { + if (bs->backing_hd) { + assert(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) { + error_free(bs->backing_blocker); + bs->backing_blocker = NULL; 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); } @@ -1803,8 +1819,9 @@ 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); @@ -2006,7 +2023,6 @@ 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)); @@ -2025,7 +2041,6 @@ 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 1c38aa8..94c8661 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -498,7 +498,7 @@ immediate_exit: /* drop the bs loop chain formed by the swap: break the loop then * trigger the unref from the top one */ BlockDriverState *p = s->base->backing_hd; - s->base->backing_hd = NULL; + bdrv_set_backing_hd(s->base, NULL); bdrv_unref(p); } } diff --git a/include/block/block_int.h b/include/block/block_int.h index 7b1c013..f2e753f 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -369,6 +369,9 @@ struct BlockDriverState { QDict *options; BlockdevDetectZeroesOptions detect_zeroes; + + /* The error object in use for blocking operations on backing_hd */ + Error *backing_blocker; }; int get_tmp_filename(char *filename, int size); -- 1.9.0