From patchwork Thu Dec 7 20:30:19 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Blake X-Patchwork-Id: 845827 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=2001:4830:134:3::11; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3yt6g513tfz9s9Y for ; Fri, 8 Dec 2017 07:35:13 +1100 (AEDT) Received: from localhost ([::1]:34181 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eN2sx-0003iH-5y for incoming@patchwork.ozlabs.org; Thu, 07 Dec 2017 15:35:11 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51807) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eN2pM-0000nO-67 for qemu-devel@nongnu.org; Thu, 07 Dec 2017 15:31:29 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eN2pL-0004XZ-6b for qemu-devel@nongnu.org; Thu, 07 Dec 2017 15:31:28 -0500 Received: from mx1.redhat.com ([209.132.183.28]:58810) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eN2pI-0004Tb-9E; Thu, 07 Dec 2017 15:31:24 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5B6586A7E3; Thu, 7 Dec 2017 20:31:23 +0000 (UTC) Received: from red.redhat.com (ovpn-123-138.rdu2.redhat.com [10.10.123.138]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0F8F8612A8; Thu, 7 Dec 2017 20:31:18 +0000 (UTC) From: Eric Blake To: qemu-devel@nongnu.org Date: Thu, 7 Dec 2017 14:30:19 -0600 Message-Id: <20171207203036.14993-4-eblake@redhat.com> In-Reply-To: <20171207203036.14993-1-eblake@redhat.com> References: <20171207203036.14993-1-eblake@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Thu, 07 Dec 2017 20:31:23 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v6 03/20] file-posix: Switch to .bdrv_co_block_status() X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, vsementsov@virtuozzo.com, famz@redhat.com, qemu-block@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" We are gradually moving away from sector-based interfaces, towards byte-based. Update the file protocol driver accordingly. In want_zero mode, we continue to report fine-grained hole information (the caller wants as much mapping detail as possible); but when not in that mode, the caller prefers larger *pnum and merely cares about what offsets are allocated at this layer, rather than where the holes live. Since holes still read as zeroes at this layer (rather than deferring to a backing layer), we can take the shortcut of skipping lseek(), and merely state that all bytes are allocated. We can also drop redundant bounds checks that are already guaranteed by the block layer. Signed-off-by: Eric Blake Reviewed-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Fam Zheng --- v5: drop redundant code v4: tweak commit message [Fam], rebase to interface tweak v3: no change v2: tweak comment, add mapping support --- block/file-posix.c | 62 +++++++++++++++++++++++++----------------------------- 1 file changed, 29 insertions(+), 33 deletions(-) diff --git a/block/file-posix.c b/block/file-posix.c index 36ee89e940..e847c7cdd9 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -2128,25 +2128,24 @@ static int find_allocation(BlockDriverState *bs, off_t start, } /* - * Returns the allocation status of the specified sectors. + * Returns the allocation status of the specified offset. * - * If 'sector_num' is beyond the end of the disk image the return value is 0 - * and 'pnum' is set to 0. + * The block layer guarantees 'offset' and 'bytes' are within bounds. * - * 'pnum' is set to the number of sectors (including and immediately following - * the specified sector) that are known to be in the same + * 'pnum' is set to the number of bytes (including and immediately following + * the specified offset) that are known to be in the same * allocated/unallocated state. * - * 'nb_sectors' is the max value 'pnum' should be set to. If nb_sectors goes - * beyond the end of the disk image it will be clamped. + * 'bytes' is the max value 'pnum' should be set to. */ -static int64_t coroutine_fn raw_co_get_block_status(BlockDriverState *bs, - int64_t sector_num, - int nb_sectors, int *pnum, - BlockDriverState **file) +static int coroutine_fn raw_co_block_status(BlockDriverState *bs, + bool want_zero, + int64_t offset, + int64_t bytes, int64_t *pnum, + int64_t *map, + BlockDriverState **file) { - off_t start, data = 0, hole = 0; - int64_t total_size; + off_t data = 0, hole = 0; int ret; ret = fd_open(bs); @@ -2154,39 +2153,36 @@ static int64_t coroutine_fn raw_co_get_block_status(BlockDriverState *bs, return ret; } - start = sector_num * BDRV_SECTOR_SIZE; - total_size = bdrv_getlength(bs); - if (total_size < 0) { - return total_size; - } else if (start >= total_size) { - *pnum = 0; - return 0; - } else if (start + nb_sectors * BDRV_SECTOR_SIZE > total_size) { - nb_sectors = DIV_ROUND_UP(total_size - start, BDRV_SECTOR_SIZE); + if (!want_zero) { + *pnum = bytes; + *map = offset; + *file = bs; + return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID; } - ret = find_allocation(bs, start, &data, &hole); + ret = find_allocation(bs, offset, &data, &hole); if (ret == -ENXIO) { /* Trailing hole */ - *pnum = nb_sectors; + *pnum = bytes; ret = BDRV_BLOCK_ZERO; } else if (ret < 0) { /* No info available, so pretend there are no holes */ - *pnum = nb_sectors; + *pnum = bytes; ret = BDRV_BLOCK_DATA; - } else if (data == start) { - /* On a data extent, compute sectors to the end of the extent, + } else if (data == offset) { + /* On a data extent, compute bytes to the end of the extent, * possibly including a partial sector at EOF. */ - *pnum = MIN(nb_sectors, DIV_ROUND_UP(hole - start, BDRV_SECTOR_SIZE)); + *pnum = MIN(bytes, hole - offset); ret = BDRV_BLOCK_DATA; } else { - /* On a hole, compute sectors to the beginning of the next extent. */ - assert(hole == start); - *pnum = MIN(nb_sectors, (data - start) / BDRV_SECTOR_SIZE); + /* On a hole, compute bytes to the beginning of the next extent. */ + assert(hole == offset); + *pnum = MIN(bytes, data - offset); ret = BDRV_BLOCK_ZERO; } + *map = offset; *file = bs; - return ret | BDRV_BLOCK_OFFSET_VALID | start; + return ret | BDRV_BLOCK_OFFSET_VALID; } static coroutine_fn BlockAIOCB *raw_aio_pdiscard(BlockDriverState *bs, @@ -2280,7 +2276,7 @@ BlockDriver bdrv_file = { .bdrv_close = raw_close, .bdrv_create = raw_create, .bdrv_has_zero_init = bdrv_has_zero_init_1, - .bdrv_co_get_block_status = raw_co_get_block_status, + .bdrv_co_block_status = raw_co_block_status, .bdrv_co_pwrite_zeroes = raw_co_pwrite_zeroes, .bdrv_co_preadv = raw_co_preadv,