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Mon, 27 Jul 2020 07:43:08 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 92AF21138648; Mon, 27 Jul 2020 09:43:06 +0200 (CEST) From: Markus Armbruster To: Daniel P. =?utf-8?Q?Berrang=C3=A9?= Subject: Re: [PATCH v3 4/4] block: switch to use qemu_open/qemu_create for improved errors References: <20200724132510.3250311-1-berrange@redhat.com> <20200724132510.3250311-5-berrange@redhat.com> Date: Mon, 27 Jul 2020 09:43:06 +0200 In-Reply-To: <20200724132510.3250311-5-berrange@redhat.com> ("Daniel P. =?utf-8?Q?Berrang=C3=A9=22's?= message of "Fri, 24 Jul 2020 14:25:10 +0100") Message-ID: <875za9769h.fsf@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=207.211.31.120; envelope-from=armbru@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/27 00:16:29 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, 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_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, 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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Max Reitz , qemu-devel@nongnu.org, qemu-block@nongnu.org, Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Daniel P. Berrang=C3=A9 writes: > Currently at startup if using cache=3Dnone on a filesystem lacking > O_DIRECT such as tmpfs, at startup QEMU prints > > qemu-system-x86_64: -drive file=3D/tmp/foo.img,cache=3Dnone: file system = may not support O_DIRECT > qemu-system-x86_64: -drive file=3D/tmp/foo.img,cache=3Dnone: Could not op= en '/tmp/foo.img': Invalid argument > > while at QMP level the hint is missing, so QEMU reports just > > "error": { > "class": "GenericError", > "desc": "Could not open '/tmp/foo.img': Invalid argument" > } > > which is close to useless for the end user trying to figure out what > they did wrong. > > With this change at startup QEMU prints > > qemu-system-x86_64: -drive file=3D/tmp/foo.img,cache=3Dnone: Unable to op= en '/tmp/foo.img' flags 0x4000: filesystem does not support O_DIRECT > > while at the QMP level QEMU reports a massively more informative > > "error": { > "class": "GenericError", > "desc": "Unable to open '/tmp/foo.img' flags 0x4002: filesystem does= not support O_DIRECT" > } > > Signed-off-by: Daniel P. Berrang=C3=A9 Subject promises slightly more than the patch actually provides: block/vvfat.c:1355: int fd =3D qemu_open(mapping->path, O_RDONLY= | O_BINARY | O_LARGEFILE); block/vvfat.c:2516: fd =3D qemu_open(mapping->path, O_RDWR | O_CREAT= | O_BINARY, 0666); If you'd rather not touch block/vvfat.c (I understand), consider tweaking the subject to say block/file: ...