From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51597) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VTVxo-00016r-92 for qemu-devel@nongnu.org; Tue, 08 Oct 2013 08:00:37 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VTVxe-0003xK-LC for qemu-devel@nongnu.org; Tue, 08 Oct 2013 08:00:32 -0400 Received: from mx.ipv6.kamp.de ([2a02:248:0:51::16]:37951 helo=mx01.kamp.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VTVxe-0003wv-7E for qemu-devel@nongnu.org; Tue, 08 Oct 2013 08:00:22 -0400 From: Peter Lieven Date: Tue, 8 Oct 2013 13:57:58 +0200 Message-Id: <1381233491-17019-5-git-send-email-pl@kamp.de> In-Reply-To: <1381233491-17019-1-git-send-email-pl@kamp.de> References: <1381233491-17019-1-git-send-email-pl@kamp.de> Subject: [Qemu-devel] [PATCHv4 04/17] block: introduce bdrv_has_discard_zeroes and bdrv_has_discard_write_zeroes 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.c | 29 +++++++++++++++++++++++++++++ include/block/block.h | 2 ++ include/block/block_int.h | 13 +++++++++++++ 3 files changed, 44 insertions(+) diff --git a/block.c b/block.c index 0675257..6a46bc2 100644 --- a/block.c +++ b/block.c @@ -3085,6 +3085,35 @@ int bdrv_has_zero_init(BlockDriverState *bs) return 0; } +bool bdrv_has_discard_zeroes(BlockDriverState *bs) +{ + assert(bs->drv); + + if (bs->backing_hd) { + return false; + } + if (bs->drv->bdrv_has_discard_zeroes) { + return bs->drv->bdrv_has_discard_zeroes(bs); + } + + return false; +} + +bool bdrv_has_discard_write_zeroes(BlockDriverState *bs) +{ + assert(bs->drv); + + if (bs->backing_hd || !(bs->open_flags & BDRV_O_UNMAP)) { + return false; + } + + if (bs->drv->bdrv_has_discard_write_zeroes) { + return bs->drv->bdrv_has_discard_write_zeroes(bs); + } + + return false; +} + typedef struct BdrvCoGetBlockStatusData { BlockDriverState *bs; BlockDriverState *base; diff --git a/include/block/block.h b/include/block/block.h index b72c81a..2de226f 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -310,6 +310,8 @@ int bdrv_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors); int bdrv_co_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors); int bdrv_has_zero_init_1(BlockDriverState *bs); int bdrv_has_zero_init(BlockDriverState *bs); +bool bdrv_has_discard_zeroes(BlockDriverState *bs); +bool bdrv_has_discard_write_zeroes(BlockDriverState *bs); int64_t bdrv_get_block_status(BlockDriverState *bs, int64_t sector_num, int nb_sectors, int *pnum); int bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, int nb_sectors, diff --git a/include/block/block_int.h b/include/block/block_int.h index f95dba7..ce5c62e 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -217,6 +217,19 @@ struct BlockDriver { */ int (*bdrv_has_zero_init)(BlockDriverState *bs); + /* + * Returns true if discarded blocks read back as zeroes. + */ + bool (*bdrv_has_discard_zeroes)(BlockDriverState *bs); + + /* + * Returns true if the driver can optimize writing zeroes by discarding + * sectors. It is additionally required that the block device is + * opened with BDRV_O_UNMAP and the that write zeroes request carries + * the BDRV_REQ_MAY_UNMAP flag for this to work. + */ + bool (*bdrv_has_discard_write_zeroes)(BlockDriverState *bs); + QLIST_ENTRY(BlockDriver) list; }; -- 1.7.9.5