From mboxrd@z Thu Jan 1 00:00:00 1970 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 3337AC369B2 for ; Thu, 17 Apr 2025 15:03:26 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1u5QlF-0004Hi-7r; Thu, 17 Apr 2025 11:02:41 -0400 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 1u5QlD-0004Fk-HB for qemu-devel@nongnu.org; Thu, 17 Apr 2025 11:02:39 -0400 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 1u5QlA-0008Mr-GM for qemu-devel@nongnu.org; Thu, 17 Apr 2025 11:02:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1744902155; 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: in-reply-to:in-reply-to:references:references; bh=M0BpeQ+x6RViPhM7rsbZIPxlT6aM0YrZAr6a5GDf45I=; b=FpkkoLN1uz6ZLC9C9tymcK5q2iyKWtqRvRLywOW4/h2Kg8WQSnDsRkjy0GCpdtRA1fakL4 56Y6IAtbFWs4DhsB2ZUNgb1VBBJfSxyHwbNMNTIRyv9lIqr6NhJqElKNdoFG1EZALHkdgN d3BWmwA1N92gq1hdEC1gePgT6Z8QfLY= Received: from mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-615--Nik6wWnMMO618MO-vVERg-1; Thu, 17 Apr 2025 11:02:32 -0400 X-MC-Unique: -Nik6wWnMMO618MO-vVERg-1 X-Mimecast-MFC-AGG-ID: -Nik6wWnMMO618MO-vVERg_1744902151 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id D720519560BB; Thu, 17 Apr 2025 15:02:30 +0000 (UTC) Received: from localhost (unknown [10.2.16.64]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 57D4419560AE; Thu, 17 Apr 2025 15:02:29 +0000 (UTC) Date: Thu, 17 Apr 2025 11:02:28 -0400 From: Stefan Hajnoczi To: Kevin Wolf Cc: qemu-devel@nongnu.org, Hanna Reitz , qemu-block@nongnu.org, Fam Zheng , eblake@redhat.com Subject: Re: [PATCH v3 2/2] block/io: skip head/tail requests on EINVAL Message-ID: <20250417150228.GC70767@fedora> References: <20250414201214.241351-1-stefanha@redhat.com> <20250414201214.241351-3-stefanha@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="AOer5y78u3SfjT2E" Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Received-SPF: pass client-ip=170.10.129.124; envelope-from=stefanha@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_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=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 --AOer5y78u3SfjT2E Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Apr 17, 2025 at 10:49:55AM +0200, Kevin Wolf wrote: > Am 14.04.2025 um 22:12 hat Stefan Hajnoczi geschrieben: > > When guests send misaligned discard requests, the block layer breaks > > them up into a misaligned head, an aligned main body, and a misaligned > > tail. > >=20 > > The file-posix block driver on Linux returns -EINVAL on misaligned > > discard requests. This causes bdrv_co_pdiscard() to fail and guests > > configured with werror=3Dstop will pause. > >=20 > > Add a special case for misaligned head/tail requests. Simply continue > > when EINVAL is encountered so that the aligned main body of the request > > can be completed and the guest is not paused. This is the best we can do > > when guest discard limits do not match the host discard limits. > >=20 > > Fixes: https://issues.redhat.com/browse/RHEL-86032 > > Signed-off-by: Stefan Hajnoczi > > Reviewed-by: Hanna Czenczek >=20 > It would be good to also update the comment a bit further up: >=20 > /* Discard is advisory, but some devices track and coalesce > * unaligned requests, so we must pass everything down rather than > * round here. Still, most devices will just silently ignore > * unaligned requests (by returning -ENOTSUP), so we must fragment > * the request accordingly. */ >=20 > I'm not sure where the -ENOTSUP came from (Eric, do you remember?), but > we should at least mention this -EINVAL case separately. Sounds good. Stefan --AOer5y78u3SfjT2E Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iQEzBAEBCgAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmgBGAQACgkQnKSrs4Gr c8i7FQgAhM8rr4crr6WdaqCQ9pO0EZfNroMioI4eAlVdc2gAd328uPwcxFZkidGc FNRhXIOYV+y0T2x0/0ufM+Gje4gDID+/wDFCXaFTdut4GWIRJdX9iLJBJJ8i1RZL w9RDa3s2x2Ue4cxyniZtJrluQACkMlDvDS+U6UPYWZw+gQ/ZgO9GS8qzI/ZImzxw mUAr0ItYt6d8Bko+SolO+hmAtFilG+AlMWJQxbfKiX21ko8q1bn+3yg4c+85Pkb7 SmKJgVUr8X05oCO3aCCYqanj8v+mj6FQdb4jihdPbbFDv5mcw1qF17mDL8STtdBd zeiEPUR4IW0W+fMEnVouRleqOm4WdA== =LzG7 -----END PGP SIGNATURE----- --AOer5y78u3SfjT2E--