From patchwork Mon Feb 27 10:47:24 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hanna Czenczek X-Patchwork-Id: 13153176 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 06F8FC64ED6 for ; Mon, 27 Feb 2023 10:48:52 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pWb2o-0001if-2F; Mon, 27 Feb 2023 05:47:46 -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 1pWb2d-0001dl-Ok for qemu-devel@nongnu.org; Mon, 27 Feb 2023 05:47:38 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pWb2c-0005Oy-2F for qemu-devel@nongnu.org; Mon, 27 Feb 2023 05:47:35 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1677494853; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=eyWqpE9+1CkDMMOO7j3zRjCLoSOlzdVHaovFbYf9L2E=; b=YN12QvnKsrtrgeGINPAgdnyANJSN3n1BM93cdCMaP2yylHI4MjuDpjQ7078jsN+sS6BPOy ha9lMfmjPdMlto/vr1nA49h50en9XOZcG7LJE4orI/dJj3oh770UVxXHAuKrYCBO3IBYyX uJFNQuZmyEC6LCCSZiWcmvCvkKNZk7Y= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-81-7UC7FokRONq6XDblWxcO2w-1; Mon, 27 Feb 2023 05:47:29 -0500 X-MC-Unique: 7UC7FokRONq6XDblWxcO2w-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 2AC901C05AB6; Mon, 27 Feb 2023 10:47:29 +0000 (UTC) Received: from localhost (unknown [10.45.228.208]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D67BD140EBF4; Mon, 27 Feb 2023 10:47:28 +0000 (UTC) From: Hanna Czenczek To: qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, Hanna Czenczek , Kevin Wolf Subject: [PATCH 1/2] block/fuse: Let PUNCH_HOLE write zeroes Date: Mon, 27 Feb 2023 11:47:24 +0100 Message-Id: <20230227104725.33511-2-hreitz@redhat.com> In-Reply-To: <20230227104725.33511-1-hreitz@redhat.com> References: <20230227104725.33511-1-hreitz@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 Received-SPF: pass client-ip=170.10.129.124; envelope-from=hreitz@redhat.com; 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, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, 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: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org fallocate(2) says about PUNCH_HOLE: "After a successful call, subsequent reads from this range will return zeros." As it is, PUNCH_HOLE is implemented as a call to blk_pdiscard(), which does not guarantee this. We must call blk_pwrite_zeroes() instead. The difference to ZERO_RANGE is that we pass the `BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK` flags to the call -- the storage is supposed to be unmapped, and a slow fallback by actually writing zeroes as data is not allowed. Closes: https://gitlab.com/qemu-project/qemu/-/issues/1507 Signed-off-by: Hanna Czenczek --- block/export/fuse.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/block/export/fuse.c b/block/export/fuse.c index e5fc4af165..06fa41079e 100644 --- a/block/export/fuse.c +++ b/block/export/fuse.c @@ -673,7 +673,16 @@ static void fuse_fallocate(fuse_req_t req, fuse_ino_t inode, int mode, do { int size = MIN(length, BDRV_REQUEST_MAX_BYTES); - ret = blk_pdiscard(exp->common.blk, offset, size); + ret = blk_pwrite_zeroes(exp->common.blk, offset, size, + BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK); + if (ret == -ENOTSUP) { + /* + * fallocate() specifies to return EOPNOTSUPP for unsupported + * operations + */ + ret = -EOPNOTSUPP; + } + offset += size; length -= size; } while (ret == 0 && length > 0);