From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34079) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d0I2K-0005M6-8S for qemu-devel@nongnu.org; Mon, 17 Apr 2017 21:34:35 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1d0I2H-0003jm-4L for qemu-devel@nongnu.org; Mon, 17 Apr 2017 21:34:32 -0400 From: Eric Blake Date: Mon, 17 Apr 2017 20:33:36 -0500 Message-Id: <20170418013356.3578-12-eblake@redhat.com> In-Reply-To: <20170418013356.3578-1-eblake@redhat.com> References: <20170418013356.3578-1-eblake@redhat.com> Subject: [Qemu-devel] [PATCH 11/31] block: Add .bdrv_co_block_status() callback List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: qemu-block@nongnu.org, kwolf@nongnu.org, jsnow@redhat.com, Stefan Hajnoczi , Fam Zheng , Kevin Wolf , Max Reitz We are gradually moving away from sector-based interfaces, towards byte-based. Now that the block layer exposes byte-based allocation, it's time to tackle the drivers. Add a new callback that operates on as small as byte boundaries, and update the block layer to ensure that the callback is only used with inputs aligned to the device's request_alignment. Subsequent patches will then update individual drivers, and then finally remove .bdrv_co_get_block_status(). Signed-off-by: Eric Blake --- include/block/block_int.h | 12 ++++++++++++ block/io.c | 47 +++++++++++++++++++++++++++++++++++------------ 2 files changed, 47 insertions(+), 12 deletions(-) diff --git a/include/block/block_int.h b/include/block/block_int.h index bc3a28a..8f20bc3 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -163,11 +163,23 @@ struct BlockDriver { */ int coroutine_fn (*bdrv_co_pwrite_zeroes)(BlockDriverState *bs, int64_t offset, int count, BdrvRequestFlags flags); + int coroutine_fn (*bdrv_co_pdiscard)(BlockDriverState *bs, int64_t offset, int count); + + /* + * Building block for bdrv_block_status[_above]. The block layer + * guarantees input aligned to request_alignment, as well as + * non-NULL pnum and file; and the result only has to worry about + * BDRV_BLOCK_DATA, _ZERO, _OFFSET_VALID, and _RAW, and only + * according to the current BDS. + */ int64_t coroutine_fn (*bdrv_co_get_block_status)(BlockDriverState *bs, int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file); + int64_t coroutine_fn (*bdrv_co_block_status)(BlockDriverState *bd, + int64_t offset, int64_t bytes, int64_t *pnum, + BlockDriverState **file); /* * Invalidate any cached meta-data. diff --git a/block/io.c b/block/io.c index 1b101cf..361eeb8 100644 --- a/block/io.c +++ b/block/io.c @@ -1718,7 +1718,6 @@ static int64_t coroutine_fn bdrv_co_block_status(BlockDriverState *bs, int64_t total_size; int64_t n; /* bytes */ int64_t ret, ret2; - int count; /* sectors */ BlockDriverState *tmp_file; total_size = bdrv_getlength(bs); @@ -1739,7 +1738,7 @@ static int64_t coroutine_fn bdrv_co_block_status(BlockDriverState *bs, bytes = n; } - if (!bs->drv->bdrv_co_get_block_status) { + if (!bs->drv->bdrv_co_get_block_status && !bs->drv->bdrv_co_block_status) { *pnum = bytes; ret = BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED; if (bs->drv->protocol_name) { @@ -1753,20 +1752,44 @@ static int64_t coroutine_fn bdrv_co_block_status(BlockDriverState *bs, } *file = NULL; bdrv_inc_in_flight(bs); - /* TODO: Rather than require aligned offsets, we could instead - * round to the driver's request_alignment here, then touch up - * count afterwards back to the caller's expectations. But first - * we want to switch the driver callback to likewise be - * byte-based. */ - assert(QEMU_IS_ALIGNED(offset | bytes, BDRV_SECTOR_SIZE)); - ret = bs->drv->bdrv_co_get_block_status(bs, offset >> BDRV_SECTOR_BITS, - bytes >> BDRV_SECTOR_BITS, &count, - file); + if (bs->drv->bdrv_co_get_block_status) { + int count; /* sectors */ + + assert(QEMU_IS_ALIGNED(offset | bytes, BDRV_SECTOR_SIZE)); + ret = bs->drv->bdrv_co_get_block_status(bs, offset >> BDRV_SECTOR_BITS, + bytes >> BDRV_SECTOR_BITS, + &count, file); + *pnum = count * BDRV_SECTOR_SIZE; + } else { + /* Round out to request_alignment boundaries */ + int64_t aligned_offset, aligned_bytes; + + aligned_offset = QEMU_ALIGN_DOWN(offset, bs->bl.request_alignment); + aligned_bytes = ROUND_UP(offset + bytes, + bs->bl.request_alignment) - aligned_offset; + ret = bs->drv->bdrv_co_block_status(bs, aligned_offset, aligned_bytes, + &n, file); + /* Clamp pnum and ret to original request */ + if (aligned_offset != offset && ret >= 0) { + int sectors = DIV_ROUND_UP(offset, BDRV_SECTOR_SIZE) - + DIV_ROUND_UP(aligned_offset, BDRV_SECTOR_SIZE); + + assert(n >= offset - aligned_offset); + n -= offset - aligned_offset; + if (sectors) { + ret += sectors * BDRV_SECTOR_SIZE; + } + } + if (ret >= 0 && n > bytes) { + assert(aligned_bytes != bytes); + n = bytes; + } + *pnum = n; + } if (ret < 0) { *pnum = 0; goto out; } - *pnum = count * BDRV_SECTOR_SIZE; if (ret & BDRV_BLOCK_RAW) { assert(ret & BDRV_BLOCK_OFFSET_VALID); -- 2.9.3