From patchwork Wed Jan 8 10:07:43 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fam Zheng X-Patchwork-Id: 308224 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 6B2EE2C00C1 for ; Wed, 8 Jan 2014 22:38:33 +1100 (EST) Received: from localhost ([::1]:45945 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W0q5R-0006ST-KD for incoming@patchwork.ozlabs.org; Wed, 08 Jan 2014 05:10:09 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55812) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W0q3q-0005Yj-PW for qemu-devel@nongnu.org; Wed, 08 Jan 2014 05:08:36 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1W0q3k-000887-F9 for qemu-devel@nongnu.org; Wed, 08 Jan 2014 05:08:30 -0500 Received: from mx1.redhat.com ([209.132.183.28]:64502) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W0q3k-00087v-7g for qemu-devel@nongnu.org; Wed, 08 Jan 2014 05:08:24 -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 s08A8NxI018058 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Wed, 8 Jan 2014 05:08:23 -0500 Received: from ad.nay.redhat.com ([10.66.6.190]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id s08A85dc014883; Wed, 8 Jan 2014 05:08:19 -0500 From: Fam Zheng To: qemu-devel@nongnu.org Date: Wed, 8 Jan 2014 18:07:43 +0800 Message-Id: <1389175672-25109-3-git-send-email-famz@redhat.com> In-Reply-To: <1389175672-25109-1-git-send-email-famz@redhat.com> References: <1389175672-25109-1-git-send-email-famz@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: kwolf@redhat.com, rjones@redhat.com, armbru@redhat.com, imain@redhat.com, stefanha@redhat.com, pbonzini@redhat.com Subject: [Qemu-devel] [PATCH v11 02/11] block: Introduce op_blockers to BlockDriverState X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org 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;