From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42774) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W0k36-0001mL-9C for qemu-devel@nongnu.org; Tue, 07 Jan 2014 22:43:26 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1W0k30-0002Wn-3a for qemu-devel@nongnu.org; Tue, 07 Jan 2014 22:43:20 -0500 Received: from mx1.redhat.com ([209.132.183.28]:23168) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W0k2z-0002Wj-RP for qemu-devel@nongnu.org; Tue, 07 Jan 2014 22:43:14 -0500 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s083hD2Q011427 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 7 Jan 2014 22:43:13 -0500 From: Fam Zheng Date: Wed, 8 Jan 2014 11:42:41 +0800 Message-Id: <1389152570-1815-3-git-send-email-famz@redhat.com> In-Reply-To: <1389152570-1815-1-git-send-email-famz@redhat.com> References: <1389152570-1815-1-git-send-email-famz@redhat.com> Subject: [Qemu-devel] [PATCH v10 02/11] 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, rjones@redhat.com, armbru@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 the existing bdrv_set_in_use()). * 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 | 71 +++++++++++++++++++++++++++++++++++++++++++++++ include/block/block.h | 7 +++++ include/block/block_int.h | 5 ++++ 3 files changed, 83 insertions(+) diff --git a/block.c b/block.c index 64e7d22..91cda9c 100644 --- a/block.c +++ b/block.c @@ -1627,6 +1627,8 @@ static void bdrv_move_feature_fields(BlockDriverState *bs_dest, /* keep the same entry in bdrv_states */ pstrcpy(bs_dest->device_name, sizeof(bs_dest->device_name), bs_src->device_name); + memcpy(bs_dest->op_blockers, bs_src->op_blockers, + sizeof(bs_dest->op_blockers)); bs_dest->list = bs_src->list; } @@ -4634,6 +4636,75 @@ 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); + } +} + +bool bdrv_op_blocker_is_empty(BlockDriverState *bs) +{ + int i; + + for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) { + if (!QLIST_EMPTY(&bs->op_blockers[i])) { + return false; + } + } + return true; +} + 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 2bc39fe..e6073e7 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -461,6 +461,13 @@ 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); +bool bdrv_op_blocker_is_empty(BlockDriverState *bs); + #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 8b132d7..458acd6 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -252,6 +252,8 @@ typedef struct BlockLimits { int opt_transfer_length; } BlockLimits; +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 @@ -333,6 +335,9 @@ struct BlockDriverState { QLIST_HEAD(, BdrvTrackedRequest) tracked_requests; + /* operation blockers */ + QLIST_HEAD(, BdrvOpBlocker) op_blockers[BLOCK_OP_TYPE_MAX]; + /* long-running background operation */ BlockJob *job; -- 1.8.5.1