From patchwork Tue Sep 24 13:35:07 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Lieven X-Patchwork-Id: 277506 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 5A6592C0097 for ; Tue, 24 Sep 2013 23:43:46 +1000 (EST) Received: from localhost ([::1]:46142 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VOSu0-00046b-DH for incoming@patchwork.ozlabs.org; Tue, 24 Sep 2013 09:43:44 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52827) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VOSo3-0004Zh-4f for qemu-devel@nongnu.org; Tue, 24 Sep 2013 09:37:40 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VOSnx-0004zn-Ed for qemu-devel@nongnu.org; Tue, 24 Sep 2013 09:37:35 -0400 Received: from mx.ipv6.kamp.de ([2a02:248:0:51::16]:60650 helo=mx01.kamp.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VOSnx-0004zU-2B for qemu-devel@nongnu.org; Tue, 24 Sep 2013 09:37:29 -0400 Received: (qmail 13749 invoked by uid 89); 24 Sep 2013 13:37:28 -0000 Received: from [82.141.1.145] by client-16-kamp (envelope-from , uid 89) with qmail-scanner-2010/03/19-MF (clamdscan: 0.98/17892. hbedv: 8.2.12.122/7.11.104.28. spamassassin: 3.3.1. Clear:RC:1(82.141.1.145):SA:0(-1.2/5.0):. Processed in 10.233253 secs); 24 Sep 2013 13:37:28 -0000 Received: from ns.kamp-intra.net (HELO dns.kamp-intra.net) ([82.141.1.145]) by mx01.kamp.de with SMTP; 24 Sep 2013 13:37:17 -0000 X-GL_Whitelist: yes Received: from lieven-pc.kamp-intra.net (lieven-pc.kamp-intra.net [172.21.12.60]) by dns.kamp-intra.net (Postfix) with ESMTP id 26928206B6; Tue, 24 Sep 2013 15:35:16 +0200 (CEST) Received: by lieven-pc.kamp-intra.net (Postfix, from userid 1000) id 23BB761461; Tue, 24 Sep 2013 15:35:16 +0200 (CEST) From: Peter Lieven To: qemu-devel@nongnu.org Date: Tue, 24 Sep 2013 15:35:07 +0200 Message-Id: <1380029714-5239-14-git-send-email-pl@kamp.de> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1380029714-5239-1-git-send-email-pl@kamp.de> References: <1380029714-5239-1-git-send-email-pl@kamp.de> X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-Received-From: 2a02:248:0:51::16 Cc: kwolf@redhat.com, ronniesahlberg@gmail.com, Peter Lieven , stefanha@redhat.com, anthony@codemonkey.ws, pbonzini@redhat.com Subject: [Qemu-devel] [PATCHv3 13/20] block: introduce bdrv_zeroize X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org this patch adds a call to completely zero out a block device. the operation is sped up by checking the block status and only writing zeroes to the device if they currently do not return zeroes. optionally the zero writing can be sped up by setting the flag BDRV_REQ_MAY_UNMAP to emulate the zero write by unmapping if the driver supports it. Signed-off-by: Peter Lieven Reviewed-by: Eric Blake --- block.c | 37 +++++++++++++++++++++++++++++++++++++ include/block/block.h | 1 + 2 files changed, 38 insertions(+) diff --git a/block.c b/block.c index 784e545..66b9eae 100644 --- a/block.c +++ b/block.c @@ -2398,6 +2398,43 @@ int bdrv_write_zeroes(BlockDriverState *bs, int64_t sector_num, BDRV_REQ_ZERO_WRITE | flags); } +/* + * Completely zero out a block device with the help of bdrv_write_zeroes. + * The operation is sped up by checking the block status and only writing + * zeroes to the device if they currently do not return zeroes. Optional + * flags are passed through to bdrv_write_zeroes (e.g. BDRV_REQ_MAY_UNMAP). + * + * Returns < 0 on error, 0 on success. For error codes see bdrv_write(). + */ +int bdrv_zeroize(BlockDriverState *bs, BdrvRequestFlags flags) +{ + int64_t target_size = bdrv_getlength(bs) / BDRV_SECTOR_SIZE; + int64_t ret, nb_sectors, sector_num = 0; + int n; + + for (;;) { + nb_sectors = target_size - sector_num; + if (nb_sectors <= 0) { + return 0; + } + if (nb_sectors > INT_MAX) { + nb_sectors = INT_MAX; + } + ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n); + if (ret & BDRV_BLOCK_ZERO) { + sector_num += n; + continue; + } + ret = bdrv_write_zeroes(bs, sector_num, n, flags); + if (ret < 0) { + error_report("error writing zeroes at sector %" PRId64 ": %s", + sector_num, strerror(-ret)); + return ret; + } + sector_num += n; + } +} + int bdrv_pread(BlockDriverState *bs, int64_t offset, void *buf, int count1) { diff --git a/include/block/block.h b/include/block/block.h index 2de226f..e059188 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -196,6 +196,7 @@ int bdrv_write(BlockDriverState *bs, int64_t sector_num, const uint8_t *buf, int nb_sectors); int bdrv_write_zeroes(BlockDriverState *bs, int64_t sector_num, int nb_sectors, BdrvRequestFlags flags); +int bdrv_zeroize(BlockDriverState *bs, BdrvRequestFlags flags); int bdrv_writev(BlockDriverState *bs, int64_t sector_num, QEMUIOVector *qiov); int bdrv_pread(BlockDriverState *bs, int64_t offset, void *buf, int count);