From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52554) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VOSn0-0002fm-Js for qemu-devel@nongnu.org; Tue, 24 Sep 2013 09:36:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VOSmp-0004Tp-Vw for qemu-devel@nongnu.org; Tue, 24 Sep 2013 09:36:30 -0400 Received: from mx.ipv6.kamp.de ([2a02:248:0:51::16]:49432 helo=mx01.kamp.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VOSmp-0004TT-LC for qemu-devel@nongnu.org; Tue, 24 Sep 2013 09:36:19 -0400 From: Peter Lieven Date: Tue, 24 Sep 2013 15:34:57 +0200 Message-Id: <1380029714-5239-4-git-send-email-pl@kamp.de> In-Reply-To: <1380029714-5239-1-git-send-email-pl@kamp.de> References: <1380029714-5239-1-git-send-email-pl@kamp.de> Subject: [Qemu-devel] [PATCHv3 03/20] block: introduce BDRV_REQ_MAY_UNMAP request flag List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, ronniesahlberg@gmail.com, Peter Lieven , stefanha@redhat.com, anthony@codemonkey.ws, pbonzini@redhat.com Reviewed-by: Eric Blake Signed-off-by: Peter Lieven --- block-migration.c | 3 ++- block.c | 4 ++++ block/backup.c | 2 +- include/block/block.h | 7 +++++++ 4 files changed, 14 insertions(+), 2 deletions(-) diff --git a/block-migration.c b/block-migration.c index 713a8e3..fc4ef93 100644 --- a/block-migration.c +++ b/block-migration.c @@ -780,7 +780,8 @@ static int block_load(QEMUFile *f, void *opaque, int version_id) } if (flags & BLK_MIG_FLAG_ZERO_BLOCK) { - ret = bdrv_write_zeroes(bs, addr, nr_sectors, 0); + ret = bdrv_write_zeroes(bs, addr, nr_sectors, + BDRV_REQ_MAY_UNMAP); } else { buf = g_malloc(BLOCK_SIZE); qemu_get_buffer(f, buf, BLOCK_SIZE); diff --git a/block.c b/block.c index c453ec1..e7bf6af 100644 --- a/block.c +++ b/block.c @@ -2817,6 +2817,10 @@ int coroutine_fn bdrv_co_write_zeroes(BlockDriverState *bs, { trace_bdrv_co_write_zeroes(bs, sector_num, nb_sectors); + if (!(bs->open_flags & BDRV_O_UNMAP)) { + flags &= ~BDRV_REQ_MAY_UNMAP; + } + return bdrv_co_do_writev(bs, sector_num, nb_sectors, NULL, BDRV_REQ_ZERO_WRITE | flags); } diff --git a/block/backup.c b/block/backup.c index 5f6a642..1ab080d 100644 --- a/block/backup.c +++ b/block/backup.c @@ -139,7 +139,7 @@ static int coroutine_fn backup_do_cow(BlockDriverState *bs, if (buffer_is_zero(iov.iov_base, iov.iov_len)) { ret = bdrv_co_write_zeroes(job->target, start * BACKUP_SECTORS_PER_CLUSTER, - n, 0); + n, BDRV_REQ_MAY_UNMAP); } else { ret = bdrv_co_writev(job->target, start * BACKUP_SECTORS_PER_CLUSTER, n, diff --git a/include/block/block.h b/include/block/block.h index 47c6475..b72c81a 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -65,6 +65,13 @@ typedef struct BlockDevOps { typedef enum { BDRV_REQ_COPY_ON_READ = 0x1, BDRV_REQ_ZERO_WRITE = 0x2, + /* The BDRV_REQ_MAY_UNMAP flag is used to indicate that the block driver + * is allowed to optimize a write zeroes request by unmapping (discarding) + * blocks if it is guaranteed that the result will read back as + * zeroes. The flag is only passed to the driver if the block device is + * opened with BDRV_O_UNMAP. + */ + BDRV_REQ_MAY_UNMAP = 0x4, } BdrvRequestFlags; #define BDRV_O_RDWR 0x0002 -- 1.7.9.5