From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:45759) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SWrmD-0007Il-Eu for qemu-devel@nongnu.org; Tue, 22 May 2012 12:17:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SWrmB-0001Zc-Nt for qemu-devel@nongnu.org; Tue, 22 May 2012 12:17:37 -0400 Received: from mail-pz0-f45.google.com ([209.85.210.45]:34090) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SWrmB-0001ZD-FC for qemu-devel@nongnu.org; Tue, 22 May 2012 12:17:35 -0400 Received: by dadv2 with SMTP id v2so10214735dad.4 for ; Tue, 22 May 2012 09:17:33 -0700 (PDT) Sender: Paolo Bonzini From: Paolo Bonzini Date: Tue, 22 May 2012 18:17:12 +0200 Message-Id: <1337703438-9764-2-git-send-email-pbonzini@redhat.com> In-Reply-To: <1337703438-9764-1-git-send-email-pbonzini@redhat.com> References: <1337703438-9764-1-git-send-email-pbonzini@redhat.com> Subject: [Qemu-devel] [PATCH 1.2 1/7] block: flush in writethrough mode after writes List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com We want to make the formats handle their own flushes autonomously, while keeping for guests the ability to use a writethrough cache. Since formats will write metadata via bs->file, bdrv_co_do_writev is the only place where we need to add a flush. Signed-off-by: Paolo Bonzini --- block.c | 11 +++++++++-- 1 files changed, 9 insertions(+), 2 deletions(-) diff --git a/block.c b/block.c index af2ab4f..7add33c 100644 --- a/block.c +++ b/block.c @@ -1747,8 +1747,8 @@ int bdrv_pwrite_sync(BlockDriverState *bs, int64_t offset, return ret; } - /* No flush needed for cache modes that use O_DSYNC */ - if ((bs->open_flags & BDRV_O_CACHE_WB) != 0) { + /* No flush needed for cache modes that already do it */ + if (bs->enable_write_cache) { bdrv_flush(bs); } @@ -1797,6 +1797,9 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BlockDriverState *bs, ret = bdrv_co_do_write_zeroes(bs, cluster_sector_num, cluster_nb_sectors); } else { + /* This does not change the data on the disk, it is not necessary + * to flush even in cache=writethrough mode. + */ ret = drv->bdrv_co_writev(bs, cluster_sector_num, cluster_nb_sectors, &bounce_qiov); } @@ -1966,6 +1969,10 @@ static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs, ret = drv->bdrv_co_writev(bs, sector_num, nb_sectors, qiov); } + if (ret == 0 && !bs->enable_write_cache) { + ret = bdrv_co_flush(bs); + } + if (bs->dirty_bitmap) { set_dirty_bitmap(bs, sector_num, nb_sectors, 1); } -- 1.7.1