{"id":2229020,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2229020/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260427170520.101242-3-kwolf@redhat.com/","project":{"id":14,"url":"http://patchwork.ozlabs.org/api/1.1/projects/14/?format=json","name":"QEMU Development","link_name":"qemu-devel","list_id":"qemu-devel.nongnu.org","list_email":"qemu-devel@nongnu.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20260427170520.101242-3-kwolf@redhat.com>","date":"2026-04-27T17:05:18","name":"[2/4] qemu-io: Add 'aio_discard' command","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"7fb3aacce2201c4d65c10547ba7f7a2bd578d643","submitter":{"id":2714,"url":"http://patchwork.ozlabs.org/api/1.1/people/2714/?format=json","name":"Kevin Wolf","email":"kwolf@redhat.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260427170520.101242-3-kwolf@redhat.com/mbox/","series":[{"id":501688,"url":"http://patchwork.ozlabs.org/api/1.1/series/501688/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/list/?series=501688","date":"2026-04-27T17:05:16","name":"qcow2: Fix corruption on discard during write with COW","version":1,"mbox":"http://patchwork.ozlabs.org/series/501688/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2229020/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2229020/checks/","tags":{},"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=mimecast20190719 header.b=A1e6yITK;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; helo=lists1p.gnu.org;\n envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n receiver=patchwork.ozlabs.org)"],"Received":["from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17])\n\t(using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4g492B2c9gz1xvV\n\tfor ; Tue, 28 Apr 2026 03:06:10 +1000 (AEST)","from localhost ([::1] helo=lists1p.gnu.org)\n\tby lists1p.gnu.org with esmtp (Exim 4.90_1)\n\t(envelope-from )\n\tid 1wHPP8-0007c7-0k; Mon, 27 Apr 2026 13:05:54 -0400","from eggs.gnu.org ([2001:470:142:3::10])\n by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)\n (Exim 4.90_1) (envelope-from ) id 1wHPP5-0007af-H5\n for qemu-devel@nongnu.org; Mon, 27 Apr 2026 13:05:51 -0400","from us-smtp-delivery-124.mimecast.com ([170.10.133.124])\n by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)\n (Exim 4.90_1) (envelope-from ) id 1wHPP3-0006TS-OR\n for qemu-devel@nongnu.org; Mon, 27 Apr 2026 13:05:51 -0400","from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com\n (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by\n relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3,\n cipher=TLS_AES_256_GCM_SHA384) id us-mta-148-euhHDi6PP8q6vcHVmnplng-1; Mon,\n 27 Apr 2026 13:05:45 -0400","from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com\n (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111])\n (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest\n SHA256)\n (No client certificate requested)\n by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS\n id 65FF819560B0; Mon, 27 Apr 2026 17:05:44 +0000 (UTC)","from merkur.fritz.box (unknown [10.44.49.22])\n by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP\n id 440F71800446; Mon, 27 Apr 2026 17:05:42 +0000 (UTC)"],"DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com;\n s=mimecast20190719; t=1777309549;\n h=from:from:reply-to:subject:subject:date:date:message-id:message-id:\n to:to:cc:cc:mime-version:mime-version:\n content-transfer-encoding:content-transfer-encoding:\n in-reply-to:in-reply-to:references:references;\n bh=3kv75jBc4wfec0Dved34GH/yumDj1olUf9AKVp+bi4g=;\n b=A1e6yITKIB/c5C863dyjtv8M+654qKx5T3XXX4z6Uzf6mAMrWg9BBkeKa6QlqWLSSP6ec3\n T3sKCbH4wffxATcewHjsUcWIMlqq556MdDMnBh3A1Kn7jnQ4Ltm/Z/WrN6WTy1pepWrJXU\n JH+y4bB0qFuJfb5ykSngyMm8Fp3hC0U=","X-MC-Unique":"euhHDi6PP8q6vcHVmnplng-1","X-Mimecast-MFC-AGG-ID":"euhHDi6PP8q6vcHVmnplng_1777309544","From":"Kevin Wolf ","To":"qemu-block@nongnu.org","Cc":"kwolf@redhat.com, hreitz@redhat.com, den@openvz.org, stefanha@redhat.com,\n qemu-stable@nongnu.org, qemu-devel@nongnu.org","Subject":"[PATCH 2/4] qemu-io: Add 'aio_discard' command","Date":"Mon, 27 Apr 2026 19:05:18 +0200","Message-ID":"<20260427170520.101242-3-kwolf@redhat.com>","In-Reply-To":"<20260427170520.101242-1-kwolf@redhat.com>","References":"<20260427170520.101242-1-kwolf@redhat.com>","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","X-Scanned-By":"MIMEDefang 3.4.1 on 10.30.177.111","Received-SPF":"pass client-ip=170.10.133.124; envelope-from=kwolf@redhat.com;\n helo=us-smtp-delivery-124.mimecast.com","X-Spam_score_int":"-20","X-Spam_score":"-2.1","X-Spam_bar":"--","X-Spam_report":"(-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001,\n DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\n RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001,\n SPF_HELO_PASS=-0.001,\n SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no","X-Spam_action":"no action","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"qemu development ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"},"content":"Testing interactions between multiple requests that include discard\nrequests require that qemu-io can do the discard asynchronously, like it\nalready does for reads and writes. To this effect, add an 'aio_discard'\ncommand.\n\nSigned-off-by: Kevin Wolf \n---\n qemu-io-cmds.c | 113 +++++++++++++++++++++++++++++++++++++++++++++++++\n 1 file changed, 113 insertions(+)","diff":"diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c\nindex 13e03301624..0f5baa70f94 100644\n--- a/qemu-io-cmds.c\n+++ b/qemu-io-cmds.c\n@@ -2218,6 +2218,118 @@ static int discard_f(BlockBackend *blk, int argc, char **argv)\n return 0;\n }\n \n+static void aio_discard_help(void)\n+{\n+ printf(\n+\"\\n\"\n+\" asynchronously discards a range of bytes from the given offset\\n\"\n+\"\\n\"\n+\" Example:\\n\"\n+\" 'aio_discard 512 1k' - discards 1 kilobyte from 512 bytes into the file\\n\"\n+\"\\n\"\n+\" Discards a segment of the currently open file.\\n\"\n+\" -C, -- report statistics in a machine parsable format\\n\"\n+\" -q, -- quiet mode, do not show I/O statistics\\n\"\n+\" The discard is performed asynchronously and the aio_flush command must be\\n\"\n+\" used to ensure all outstanding aio requests have been completed.\\n\"\n+\" Note that due to its asynchronous nature, this command will be\\n\"\n+\" considered successful once the request is submitted, independently\\n\"\n+\" of potential I/O errors.\\n\"\n+\"\\n\");\n+}\n+\n+static int aio_discard_f(BlockBackend *blk, int argc, char **argv);\n+\n+static const cmdinfo_t aio_discard_cmd = {\n+ .name = \"aio_discard\",\n+ .cfunc = aio_discard_f,\n+ .perm = BLK_PERM_WRITE,\n+ .argmin = 2,\n+ .argmax = -1,\n+ .args = \"[-Cq] off len\",\n+ .oneline = \"asynchronously discards a number of bytes\",\n+ .help = aio_discard_help,\n+};\n+\n+static void aio_discard_done(void *opaque, int ret)\n+{\n+ struct aio_ctx *ctx = opaque;\n+ struct timespec t2;\n+\n+ clock_gettime(CLOCK_MONOTONIC, &t2);\n+\n+ if (ret < 0) {\n+ printf(\"aio_discard failed: %s\\n\", strerror(-ret));\n+ block_acct_failed(blk_get_stats(ctx->blk), &ctx->acct);\n+ goto out;\n+ }\n+\n+ block_acct_done(blk_get_stats(ctx->blk), &ctx->acct);\n+\n+ if (ctx->qflag) {\n+ goto out;\n+ }\n+\n+ /* Finally, report back -- -C gives a parsable format */\n+ t2 = tsub(t2, ctx->t1);\n+ print_report(\"discarded \", &t2, ctx->offset, ctx->qiov.size,\n+ ctx->qiov.size, 1, ctx->Cflag);\n+out:\n+ g_free(ctx);\n+}\n+\n+static int aio_discard_f(BlockBackend *blk, int argc, char **argv)\n+{\n+ int c, ret;\n+ int64_t count;\n+ struct aio_ctx *ctx = g_new0(struct aio_ctx, 1);\n+\n+ ctx->blk = blk;\n+\n+ while ((c = getopt(argc, argv, \"Cq\")) != -1) {\n+ switch (c) {\n+ case 'C':\n+ ctx->Cflag = true;\n+ break;\n+ case 'q':\n+ ctx->qflag = true;\n+ break;\n+ default:\n+ qemuio_command_usage(&aio_discard_cmd);\n+ return -EINVAL;\n+ }\n+ }\n+\n+ if (optind != argc - 2) {\n+ qemuio_command_usage(&aio_discard_cmd);\n+ return -EINVAL;\n+ }\n+\n+ ctx->offset = cvtnum(argv[optind]);\n+ if (ctx->offset < 0) {\n+ ret = ctx->offset;\n+ print_cvtnum_err(ret, argv[optind]);\n+ g_free(ctx);\n+ return ret;\n+ }\n+ optind++;\n+\n+ count = cvtnum(argv[optind]);\n+ if (count < 0) {\n+ print_cvtnum_err(count, argv[optind]);\n+ g_free(ctx);\n+ return count;\n+ }\n+\n+ clock_gettime(CLOCK_MONOTONIC, &ctx->t1);\n+ ctx->qiov.size = count;\n+ block_acct_start(blk_get_stats(blk), &ctx->acct, ctx->qiov.size,\n+ BLOCK_ACCT_UNMAP);\n+ blk_aio_pdiscard(blk, ctx->offset, count, aio_discard_done, ctx);\n+\n+ return 0;\n+}\n+\n static int alloc_f(BlockBackend *blk, int argc, char **argv)\n {\n BlockDriverState *bs = blk_bs(blk);\n@@ -2800,6 +2912,7 @@ static void __attribute((constructor)) init_qemuio_commands(void)\n qemuio_add_command(&length_cmd);\n qemuio_add_command(&info_cmd);\n qemuio_add_command(&discard_cmd);\n+ qemuio_add_command(&aio_discard_cmd);\n qemuio_add_command(&alloc_cmd);\n qemuio_add_command(&map_cmd);\n qemuio_add_command(&reopen_cmd);\n","prefixes":["2/4"]}