From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47559) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Vl9uN-0007Av-Aj for qemu-devel@nongnu.org; Mon, 25 Nov 2013 23:06:01 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Vl9uH-0000zc-6r for qemu-devel@nongnu.org; Mon, 25 Nov 2013 23:05:55 -0500 Received: from mx1.redhat.com ([209.132.183.28]:39186) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Vl9uG-0000zY-Vh for qemu-devel@nongnu.org; Mon, 25 Nov 2013 23:05:49 -0500 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id rAQ45mBO003817 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Mon, 25 Nov 2013 23:05:48 -0500 From: Fam Zheng Date: Tue, 26 Nov 2013 12:05:23 +0800 Message-Id: <1385438728-17924-3-git-send-email-famz@redhat.com> In-Reply-To: <1385438728-17924-1-git-send-email-famz@redhat.com> References: <1385438728-17924-1-git-send-email-famz@redhat.com> Subject: [Qemu-devel] [PATCH v5 2/7] block: Introduce op_blockers to BlockDriverState List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, hbrock@redhat.com, rjones@redhat.com, imain@redhat.com, stefanha@redhat.com, pbonzini@redhat.com BlockDriverState.op_blockers is an array of lists with BLOCK_OP_TYPE_MAX elements. Each list is a list of blockers of an operation type (BlockOpType), that marks this BDS as currently blocked for a certain type of operation with reason errors stored in the list. The rule of usage is: * BDS user who wants to take an operation should check if there's any blocker of the type with bdrv_op_is_blocked(). * BDS user who wants to block certain types of operation, should call bdrv_op_block (or bdrv_op_block_all to block all types of operations, which is similar to bdrv_set_in_use of now). * A blocker is only referenced by op_blockers, so the lifecycle is managed by caller, and shouldn't be lost until unblock, so typically a caller does these: - Allocate a blocker with error_setg or similar, call bdrv_op_block() to block some operations. - Hold the blocker, do his job. - Unblock operations that it blocked, with the same reason pointer passed to bdrv_op_unblock(). - Release the blocker with error_free(). Signed-off-by: Fam Zheng --- block.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++ include/block/block.h | 6 +++++ include/block/block_int.h | 5 +++++ 3 files changed, 68 insertions(+) diff --git a/block.c b/block.c index 382ea71..45410ef 100644 --- a/block.c +++ b/block.c @@ -4425,6 +4425,63 @@ void bdrv_unref(BlockDriverState *bs) } } +struct BdrvOpBlocker { + Error *reason; + QLIST_ENTRY(BdrvOpBlocker) list; +}; + +bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp) +{ + BdrvOpBlocker *blocker; + assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX); + if (!QLIST_EMPTY(&bs->op_blockers[op])) { + blocker = QLIST_FIRST(&bs->op_blockers[op]); + if (errp) { + *errp = error_copy(blocker->reason); + } + return true; + } + return false; +} + +void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason) +{ + BdrvOpBlocker *blocker; + assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX); + + blocker = g_malloc0(sizeof(BdrvOpBlocker)); + blocker->reason = reason; + QLIST_INSERT_HEAD(&bs->op_blockers[op], blocker, list); +} + +void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason) +{ + BdrvOpBlocker *blocker, *next; + assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX); + QLIST_FOREACH_SAFE(blocker, &bs->op_blockers[op], list, next) { + if (blocker->reason == reason) { + QLIST_REMOVE(blocker, list); + g_free(blocker); + } + } +} + +void bdrv_op_block_all(BlockDriverState *bs, Error *reason) +{ + int i; + for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) { + bdrv_op_block(bs, i, reason); + } +} + +void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason) +{ + int i; + for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) { + bdrv_op_unblock(bs, i, reason); + } +} + 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 3560deb..693d305 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -403,6 +403,12 @@ void bdrv_unref(BlockDriverState *bs); void bdrv_set_in_use(BlockDriverState *bs, int in_use); int bdrv_in_use(BlockDriverState *bs); +bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp); +void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason); +void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason); +void bdrv_op_block_all(BlockDriverState *bs, Error *reason); +void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason); + #ifdef CONFIG_LINUX_AIO int raw_get_aio_fd(BlockDriverState *bs); #else diff --git a/include/block/block_int.h b/include/block/block_int.h index 1666066..d8cef85 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -230,6 +230,8 @@ struct BlockDriver { QLIST_ENTRY(BlockDriver) list; }; +typedef struct BdrvOpBlocker BdrvOpBlocker; + /* * Note: the function bdrv_append() copies and swaps contents of * BlockDriverStates, so if you add new fields to this struct, please @@ -308,6 +310,9 @@ struct BlockDriverState { QLIST_HEAD(, BdrvTrackedRequest) tracked_requests; + /* operation blockers */ + QLIST_HEAD(, BdrvOpBlocker) op_blockers[BLOCK_OP_TYPE_MAX]; + /* long-running background operation */ BlockJob *job; -- 1.8.4.2