From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37548) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Xc3op-0006ZF-Hl for qemu-devel@nongnu.org; Wed, 08 Oct 2014 22:51:15 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Xc3og-0008Ok-Uv for qemu-devel@nongnu.org; Wed, 08 Oct 2014 22:51:07 -0400 Received: from e23smtp07.au.ibm.com ([202.81.31.140]:47053) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Xc3og-0008OX-9v for qemu-devel@nongnu.org; Wed, 08 Oct 2014 22:50:58 -0400 Received: from /spool/local by e23smtp07.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 9 Oct 2014 12:50:52 +1000 Received: from d23relay04.au.ibm.com (d23relay04.au.ibm.com [9.190.234.120]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id D6D112BB0051 for ; Thu, 9 Oct 2014 13:50:49 +1100 (EST) Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by d23relay04.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id s992WITt66650144 for ; Thu, 9 Oct 2014 13:32:19 +1100 Received: from d23av01.au.ibm.com (localhost [127.0.0.1]) by d23av01.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s992omAi020148 for ; Thu, 9 Oct 2014 13:50:48 +1100 From: Alexey Kardashevskiy Date: Thu, 9 Oct 2014 13:50:46 +1100 Message-Id: <1412823046-29885-1-git-send-email-aik@ozlabs.ru> Subject: [Qemu-devel] [PATCH] block/migration: Disable cache invalidate for incoming migration List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Alexey Kardashevskiy , Kevin Wolf , Stefan Hajnoczi , Paolo Bonzini When migrated using libvirt with "--copy-storage-all", at the end of migration there is race between NBD mirroring task trying to do flush and migration completion, both end up invalidating cache. Since qcow2 driver does not handle this situation very well, random crashes happen. This disables the BDRV_O_INCOMING flag for the block device being migrated once the cache has been invalidated. Signed-off-by: Alexey Kardashevskiy --- Changes: v1 (v0 was RFC): * added a comment to nbd_export_new() as suggested by Stefan --- block.c | 18 +++++------------- migration.c | 1 - nbd.c | 6 ++++++ 3 files changed, 11 insertions(+), 14 deletions(-) diff --git a/block.c b/block.c index c5a251c..6314af7 100644 --- a/block.c +++ b/block.c @@ -5048,6 +5048,11 @@ void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp) return; } + if (!(bs->open_flags & BDRV_O_INCOMING)) { + return; + } + bs->open_flags &= ~(BDRV_O_INCOMING); + if (bs->drv->bdrv_invalidate_cache) { bs->drv->bdrv_invalidate_cache(bs, &local_err); } else if (bs->file) { @@ -5083,19 +5088,6 @@ void bdrv_invalidate_cache_all(Error **errp) } } -void bdrv_clear_incoming_migration_all(void) -{ - BlockDriverState *bs; - - QTAILQ_FOREACH(bs, &bdrv_states, device_list) { - AioContext *aio_context = bdrv_get_aio_context(bs); - - aio_context_acquire(aio_context); - bs->open_flags = bs->open_flags & ~(BDRV_O_INCOMING); - aio_context_release(aio_context); - } -} - int bdrv_flush(BlockDriverState *bs) { Coroutine *co; diff --git a/migration.c b/migration.c index 8d675b3..c49a05a 100644 --- a/migration.c +++ b/migration.c @@ -103,7 +103,6 @@ static void process_incoming_migration_co(void *opaque) } qemu_announce_self(); - bdrv_clear_incoming_migration_all(); /* Make sure all file formats flush their mutable metadata */ bdrv_invalidate_cache_all(&local_err); if (local_err) { diff --git a/nbd.c b/nbd.c index e9b539b..a7bce45 100644 --- a/nbd.c +++ b/nbd.c @@ -972,6 +972,12 @@ NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, exp->ctx = bdrv_get_aio_context(bs); bdrv_ref(bs); bdrv_add_aio_context_notifier(bs, bs_aio_attached, bs_aio_detach, exp); + /* + * NBD exports are used for non-shared storage migration. Make sure + * that BDRV_O_INCOMING is cleared and the image is ready for write + * access since the export could be available before migration handover. + */ + bdrv_invalidate_cache(bs, NULL); return exp; } -- 2.0.0