From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 38C4FC7618B for ; Thu, 25 Jul 2019 09:21:20 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 113A821951 for ; Thu, 25 Jul 2019 09:21:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 113A821951 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=virtuozzo.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:57538 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hqZw7-0007gd-CI for qemu-devel@archiver.kernel.org; Thu, 25 Jul 2019 05:21:19 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:35768) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hqZtz-0007SR-Lf for qemu-devel@nongnu.org; Thu, 25 Jul 2019 05:19:09 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hqZtx-00044Y-VN for qemu-devel@nongnu.org; Thu, 25 Jul 2019 05:19:07 -0400 Received: from relay.sw.ru ([185.231.240.75]:44230) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hqZtx-00041c-MN; Thu, 25 Jul 2019 05:19:05 -0400 Received: from [10.94.3.0] (helo=kvm.qa.sw.ru) by relay.sw.ru with esmtp (Exim 4.92) (envelope-from ) id 1hqZtt-0001bs-EN; Thu, 25 Jul 2019 12:19:01 +0300 From: Vladimir Sementsov-Ogievskiy To: qemu-devel@nongnu.org, qemu-block@nongnu.org Date: Thu, 25 Jul 2019 12:18:52 +0300 Message-Id: <20190725091900.30542-2-vsementsov@virtuozzo.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20190725091900.30542-1-vsementsov@virtuozzo.com> References: <20190725091900.30542-1-vsementsov@virtuozzo.com> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 185.231.240.75 Subject: [Qemu-devel] [PATCH v3 1/9] block: add .bdrv_need_rw_file_child_during_reopen_rw handler X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: fam@euphon.net, kwolf@redhat.com, vsementsov@virtuozzo.com, mreitz@redhat.com, den@openvz.org, jsnow@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On reopen to rw parent may need rw access to child in .prepare, for example qcow2 needs to write IN_USE flags into stored bitmaps (currently it is done in a hacky way after commit and don't work). So, let's introduce such logic. The drawback is that in worst case bdrv_reopen_set_read_only may finish with error and in some intermediate state: some nodes reopened RW and some are not. But this is a way to fix bug around reopening qcow2 bitmaps in the following commits. Signed-off-by: Vladimir Sementsov-Ogievskiy --- include/block/block_int.h | 2 + block.c | 144 ++++++++++++++++++++++++++++++++++---- 2 files changed, 133 insertions(+), 13 deletions(-) diff --git a/include/block/block_int.h b/include/block/block_int.h index 3aa1e832a8..7bd6fd68dd 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -531,6 +531,8 @@ struct BlockDriver { uint64_t parent_perm, uint64_t parent_shared, uint64_t *nperm, uint64_t *nshared); + bool (*bdrv_need_rw_file_child_during_reopen_rw)(BlockDriverState *bs); + /** * Bitmaps should be marked as 'IN_USE' in the image on reopening image * as rw. This handler should realize it. It also should unset readonly diff --git a/block.c b/block.c index cbd8da5f3b..3c8e1c59b4 100644 --- a/block.c +++ b/block.c @@ -1715,10 +1715,12 @@ static void bdrv_get_cumulative_perm(BlockDriverState *bs, uint64_t *perm, uint64_t *shared_perm); typedef struct BlockReopenQueueEntry { - bool prepared; - bool perms_checked; - BDRVReopenState state; - QSIMPLEQ_ENTRY(BlockReopenQueueEntry) entry; + bool reopened_file_child_rw; + bool changed_file_child_perm_rw; + bool prepared; + bool perms_checked; + BDRVReopenState state; + QSIMPLEQ_ENTRY(BlockReopenQueueEntry) entry; } BlockReopenQueueEntry; /* @@ -3421,6 +3423,105 @@ BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue, keep_old_opts); } +static int bdrv_reopen_set_read_only_drained(BlockDriverState *bs, + bool read_only, + Error **errp) +{ + BlockReopenQueue *queue; + QDict *opts = qdict_new(); + + qdict_put_bool(opts, BDRV_OPT_READ_ONLY, read_only); + + queue = bdrv_reopen_queue(NULL, bs, opts, true); + + return bdrv_reopen_multiple(queue, errp); +} + +/* + * handle_recursive_reopens + * + * On fail it needs rollback_recursive_reopens to be called. + */ +static int handle_recursive_reopens(BlockReopenQueueEntry *current, + Error **errp) +{ + int ret; + BlockDriverState *bs = current->state.bs; + + /* + * We use the fact that in reopen-queue children are always following + * parents. + * TODO: Switch BlockReopenQueue to be QTAILQ and use + * QTAILQ_FOREACH_REVERSE. + */ + if (QSIMPLEQ_NEXT(current, entry)) { + ret = handle_recursive_reopens(QSIMPLEQ_NEXT(current, entry), errp); + if (ret < 0) { + return ret; + } + } + + if ((current->state.flags & BDRV_O_RDWR) && bs->file && bs->drv && + bs->drv->bdrv_need_rw_file_child_during_reopen_rw && + bs->drv->bdrv_need_rw_file_child_during_reopen_rw(bs)) + { + if (!bdrv_is_writable(bs->file->bs)) { + ret = bdrv_reopen_set_read_only_drained(bs->file->bs, false, errp); + if (ret < 0) { + return ret; + } + current->reopened_file_child_rw = true; + } + + if (!(bs->file->perm & BLK_PERM_WRITE)) { + ret = bdrv_child_try_set_perm(bs->file, + bs->file->perm | BLK_PERM_WRITE, + bs->file->shared_perm, errp); + if (ret < 0) { + return ret; + } + current->changed_file_child_perm_rw = true; + } + } + + return 0; +} + +static int rollback_recursive_reopens(BlockReopenQueue *bs_queue, + Error **errp) +{ + int ret; + BlockReopenQueueEntry *bs_entry; + + /* + * We use the fact that in reopen-queue children are always following + * parents. + */ + QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) { + BlockDriverState *bs = bs_entry->state.bs; + + if (bs_entry->changed_file_child_perm_rw) { + ret = bdrv_child_try_set_perm(bs->file, + bs->file->perm & ~BLK_PERM_WRITE, + bs->file->shared_perm, errp); + + if (ret < 0) { + return ret; + } + } + + if (bs_entry->reopened_file_child_rw) { + ret = bdrv_reopen_set_read_only_drained(bs, true, errp); + + if (ret < 0) { + return ret; + } + } + } + + return 0; +} + /* * Reopen multiple BlockDriverStates atomically & transactionally. * @@ -3440,11 +3541,18 @@ BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue, */ int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp) { - int ret = -1; + int ret; BlockReopenQueueEntry *bs_entry, *next; assert(bs_queue != NULL); + ret = handle_recursive_reopens(QSIMPLEQ_FIRST(bs_queue), errp); + if (ret < 0) { + goto rollback_recursion; + } + + ret = -1; + QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) { assert(bs_entry->state.bs->quiesce_counter > 0); if (bdrv_reopen_prepare(&bs_entry->state, bs_queue, errp)) { @@ -3485,7 +3593,7 @@ int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp) ret = 0; cleanup_perm: - QSIMPLEQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) { + QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) { BDRVReopenState *state = &bs_entry->state; if (!bs_entry->perms_checked) { @@ -3502,7 +3610,7 @@ cleanup_perm: } } cleanup: - QSIMPLEQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) { + QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) { if (ret) { if (bs_entry->prepared) { bdrv_reopen_abort(&bs_entry->state); @@ -3513,8 +3621,23 @@ cleanup: if (bs_entry->state.new_backing_bs) { bdrv_unref(bs_entry->state.new_backing_bs); } + } + +rollback_recursion: + if (ret) { + Error *local_err = NULL; + int ret2 = rollback_recursive_reopens(bs_queue, &local_err); + + if (ret2 < 0) { + error_reportf_err(local_err, "Failed to rollback partially " + "succeeded reopen to RW: "); + } + } + + QSIMPLEQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) { g_free(bs_entry); } + g_free(bs_queue); return ret; @@ -3524,14 +3647,9 @@ int bdrv_reopen_set_read_only(BlockDriverState *bs, bool read_only, Error **errp) { int ret; - BlockReopenQueue *queue; - QDict *opts = qdict_new(); - - qdict_put_bool(opts, BDRV_OPT_READ_ONLY, read_only); bdrv_subtree_drained_begin(bs); - queue = bdrv_reopen_queue(NULL, bs, opts, true); - ret = bdrv_reopen_multiple(queue, errp); + ret = bdrv_reopen_set_read_only_drained(bs, read_only, errp); bdrv_subtree_drained_end(bs); return ret; -- 2.18.0