From nobody Tue Feb 10 03:38:47 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1767960620829782.5728309147613; Fri, 9 Jan 2026 04:10:20 -0800 (PST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1veBJQ-0005qU-FV; Fri, 09 Jan 2026 07:09:52 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1veBIV-0005aZ-8R; Fri, 09 Jan 2026 07:08:57 -0500 Received: from proxmox-new.maurer-it.com ([94.136.29.106]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1veBIT-00017H-AS; Fri, 09 Jan 2026 07:08:55 -0500 Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id BFE8F476DB; Fri, 09 Jan 2026 13:08:42 +0100 (CET) From: Fiona Ebner To: qemu-devel@nongnu.org Cc: qemu-block@nongnu.org, hreitz@redhat.com, kwolf@redhat.com, fam@euphon.net, stefanha@redhat.com Subject: [PATCH 2/6] block/io: add 'bytes' parameter to bdrv_padding_rmw_read() Date: Fri, 9 Jan 2026 13:08:29 +0100 Message-ID: <20260109120837.2772961-3-f.ebner@proxmox.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260109120837.2772961-1-f.ebner@proxmox.com> References: <20260109120837.2772961-1-f.ebner@proxmox.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Bm-Milter-Handled: 55990f41-d878-4baa-be0a-ee34c49e34d2 X-Bm-Transport-Timestamp: 1767960482305 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=94.136.29.106; envelope-from=f.ebner@proxmox.com; helo=proxmox-new.maurer-it.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZM-MESSAGEID: 1767960622231158500 Content-Type: text/plain; charset="utf-8" Currently, all callers use bs->bl.request_alignment. This will change when making bdrv_co_do_zero_pwritev() honor the block driver's pwrite_zeroes_alignment. Note that the alignment for reading is not necessarily the alignment for the request. In particular with qcow2 images, the total image length is not necessarily aligned to pwrite_zeroes_alignment, and in such cases, a request with that bigger alignment would cause an assertion failure. Signed-off-by: Fiona Ebner --- block/io.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/block/io.c b/block/io.c index e80aecf194..403a45f91d 100644 --- a/block/io.c +++ b/block/io.c @@ -1511,7 +1511,7 @@ static bool bdrv_init_padding(BlockDriverState *bs, } =20 static int coroutine_fn GRAPH_RDLOCK -bdrv_padding_rmw_read(BdrvChild *child, BdrvTrackedRequest *req, +bdrv_padding_rmw_read(BdrvChild *child, BdrvTrackedRequest *req, int64_t b= ytes, BdrvRequestPadding *pad, bool zero_middle) { QEMUIOVector local_qiov; @@ -1522,7 +1522,9 @@ bdrv_padding_rmw_read(BdrvChild *child, BdrvTrackedRe= quest *req, assert(req->serialising && pad->buf); =20 if (pad->head || pad->merge_reads) { - int64_t bytes =3D pad->merge_reads ? pad->buf_len : align; + if (pad->merge_reads) { + bytes =3D pad->buf_len; + } =20 qemu_iovec_init_buf(&local_qiov, pad->buf, bytes); =20 @@ -1550,13 +1552,13 @@ bdrv_padding_rmw_read(BdrvChild *child, BdrvTracked= Request *req, } =20 if (pad->tail) { - qemu_iovec_init_buf(&local_qiov, pad->tail_buf, align); + qemu_iovec_init_buf(&local_qiov, pad->tail_buf, bytes); =20 bdrv_co_debug_event(bs, BLKDBG_PWRITEV_RMW_TAIL); ret =3D bdrv_aligned_preadv( child, req, - req->overlap_offset + req->overlap_bytes - align, - align, align, &local_qiov, 0, 0); + req->overlap_offset + req->overlap_bytes - bytes, + bytes, align, &local_qiov, 0, 0); if (ret < 0) { return ret; } @@ -2166,7 +2168,7 @@ bdrv_co_do_zero_pwritev(BdrvChild *child, int64_t off= set, int64_t bytes, assert(!(flags & BDRV_REQ_NO_WAIT)); bdrv_make_request_serialising(req, align); =20 - bdrv_padding_rmw_read(child, req, &pad, true); + bdrv_padding_rmw_read(child, req, align, &pad, true); =20 if (pad.head || pad.merge_reads) { int64_t aligned_offset =3D offset & ~(align - 1); @@ -2302,7 +2304,7 @@ int coroutine_fn bdrv_co_pwritev_part(BdrvChild *chil= d, */ assert(!(flags & BDRV_REQ_NO_WAIT)); bdrv_make_request_serialising(&req, align); - bdrv_padding_rmw_read(child, &req, &pad, false); + bdrv_padding_rmw_read(child, &req, align, &pad, false); } =20 ret =3D bdrv_aligned_pwritev(child, &req, offset, bytes, align, --=20 2.47.3