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prefer-encrypt=mutual; keydata= mQENBFXOJlcBCADEyyhOTsoa/2ujoTRAJj4MKA21dkxxELVj3cuILpLTmtachWj7QW+TVG8U /PsMCFbpwsQR7oEy8eHHZwuGQsNpEtNC2G/L8Yka0BIBzv7dEgrPzIu+W3anZXQW4702+uES U29G8TP/NGfXRRHGlbBIH9KNUnOSUD2vRtpOLXkWsV5CN6vQFYgQfFvmp5ZpPeUe6xNplu8V mcTw8OSEDW/ZnxJc8TekCKZSpdzYoxfzjm7xGmZqB18VFwgJZlIibt1HE0EB4w5GsD7x5ekh awIe3RwoZgZDLQMdOitJ1tUc8aqaxvgA4tz6J6st8D8pS//m1gAoYJWGwwIVj1DjTYLtABEB AAG0HU1heCBSZWl0eiA8bXJlaXR6QHJlZGhhdC5jb20+iQFTBBMBCAA9AhsDBQkSzAMABQsJ CAcCBhUICQoLAgQWAgMBAh4BAheABQJVzie5FRhoa3A6Ly9rZXlzLmdudXBnLm5ldAAKCRD0 B9sAYdXPQDcIB/9uNkbYEex1rHKz3mr12uxYMwLOOFY9fstP5aoVJQ1nWQVB6m2cfKGdcRe1 2/nFaHSNAzT0NnKz2MjhZVmcrpyd2Gp2QyISCfb1FbT82GMtXFj1wiHmPb3CixYmWGQUUh+I AvUqsevLA+WihgBUyaJq/vuDVM1/K9Un+w+Tz5vpeMidlIsTYhcsMhn0L9wlCjoucljvbDy/ 8C9L2DUdgi3XTa0ORKeflUhdL4gucWoAMrKX2nmPjBMKLgU7WLBc8AtV+84b9OWFML6NEyo4 4cP7cM/07VlJK53pqNg5cHtnWwjHcbpGkQvx6RUx6F1My3y52vM24rNUA3+ligVEgPYBuQEN BFXOJlcBCADAmcVUNTWT6yLWQHvxZ0o47KCP8OcLqD+67T0RCe6d0LP8GsWtrJdeDIQk+T+F xO7DolQPS6iQ6Ak2/lJaPX8L0BkEAiMuLCKFU6Bn3lFOkrQeKp3u05wCSV1iKnhg0UPji9V2 W5eNfy8F4ZQHpeGUGy+liGXlxqkeRVhLyevUqfU0WgNqAJpfhHSGpBgihUupmyUg7lfUPeRM DzAN1pIqoFuxnN+BRHdAecpsLcbR8sQddXmDg9BpSKozO/JyBmaS1RlquI8HERQoe6EynJhd 64aICHDfj61rp+/0jTIcevxIIAzW70IadoS/y3DVIkuhncgDBvGbF3aBtjrJVP+5ABEBAAGJ ASUEGAEIAA8FAlXOJlcCGwwFCRLMAwAACgkQ9AfbAGHVz0CbFwf9F/PXxQR9i4N0iipISYjU sxVdjJOM2TMut+ZZcQ6NSMvhZ0ogQxJ+iEQ5OjnIputKvPVd5U7WRh+4lF1lB/NQGrGZQ1ic alkj6ocscQyFwfib+xIe9w8TG1CVGkII7+TbS5pXHRxZH1niaRpoi/hYtgzkuOPp35jJyqT/ /ELbqQTDAWcqtJhzxKLE/ugcOMK520dJDeb6x2xVES+S5LXby0D4juZlvUj+1fwZu+7Io5+B bkhSVPb/QdOVTpnz7zWNyNw+OONo1aBUKkhq2UIByYXgORPFnbfMY7QWHcjpBVw9MgC4tGeF R4bv+1nAMMxKmb5VvQCExr0eFhJUAHAhVg== Message-ID: <4741b027-7ec2-9c0f-7826-1e1d92c9d2a7@redhat.com> Date: Thu, 15 Oct 2020 17:20:37 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <20201015104152.GD4610@merkur.fritz.box> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mreitz@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="ql757v81T15NpIJ0dyYtK5yaAc41rS2Zm" Received-SPF: pass client-ip=216.205.24.124; envelope-from=mreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/15 02:38:26 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=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-1.019, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Stefan Hajnoczi , qemu-devel@nongnu.org, qemu-block@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --ql757v81T15NpIJ0dyYtK5yaAc41rS2Zm Content-Type: multipart/mixed; boundary="rqmdPSRfXN48ACF6yrqKLwm2P0oWOSjqX" --rqmdPSRfXN48ACF6yrqKLwm2P0oWOSjqX Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 15.10.20 12:41, Kevin Wolf wrote: > Am 22.09.2020 um 12:49 hat Max Reitz geschrieben: >> These will behave more like normal files in that writes beyond the EOF >> will automatically grow the export size. >> >> Signed-off-by: Max Reitz >> --- >> qapi/block-export.json | 6 +++++- >> block/export/fuse.c | 12 +++++++++++- >> 2 files changed, 16 insertions(+), 2 deletions(-) >> >> diff --git a/qapi/block-export.json b/qapi/block-export.json >> index cb5bd54cbf..cb26daa98b 100644 >> --- a/qapi/block-export.json >> +++ b/qapi/block-export.json >> @@ -183,10 +183,14 @@ >> # @mountpoint: Path on which to export the block device via FUSE. >> # This must point to an existing regular file. >> # >> +# @growable: Whether writes beyond the EOF should grow the block node >> +# accordingly. (default: false) >> +# >> # Since: 5.2 >> ## >> { 'struct': 'BlockExportOptionsFuse', >> - 'data': { 'mountpoint': 'str' }, >> + 'data': { 'mountpoint': 'str', >> + '*growable': 'bool' }, >> 'if': 'defined(CONFIG_FUSE)' } >> =20 >> ## >> diff --git a/block/export/fuse.c b/block/export/fuse.c >> index 8fc667231d..f3a84579ba 100644 >> --- a/block/export/fuse.c >> +++ b/block/export/fuse.c >> @@ -45,6 +45,7 @@ typedef struct FuseExport { >> =20 >> char *mountpoint; >> bool writable; >> + bool growable; >> } FuseExport; >> =20 >> static GHashTable *exports; >> @@ -101,6 +102,7 @@ static int fuse_export_create(BlockExport *blk_exp, >> =20 >> exp->mountpoint =3D g_strdup(args->mountpoint); >> exp->writable =3D blk_exp_args->writable; >> + exp->growable =3D args->growable; >> =20 >> ret =3D setup_fuse_export(exp, args->mountpoint, errp); >> if (ret < 0) { >> @@ -436,7 +438,15 @@ static void fuse_write(fuse_req_t req, fuse_ino_t i= node, const char *buf, >> =20 >> size =3D MIN(size, BDRV_REQUEST_MAX_BYTES); >> if (offset + size > length) { >> - size =3D length - offset; >> + if (exp->growable) { >> + ret =3D fuse_do_truncate(exp, offset + size, PREALLOC_MODE_= OFF); >=20 > Do we need BDRV_REQ_ZERO_WRITE for blk_truncate() in this case? Ah, yes. (Sorry, code is a bit old and I forgot when I revised it...) > Actually, since we export a regular file, it would probably be good for > the setattr case, too. Yes. > If someone actually uses this to sequentially write past the end of the > file, it will be quite inefficient because fuse_do_truncate() temporarily > acquires locks for each write request. It might be a good idea to > acquire BLK_PERM_RESIZE from the start for growable exports (like image > formats do for bs->file). Oh, yes, that makes sense. Max --rqmdPSRfXN48ACF6yrqKLwm2P0oWOSjqX-- --ql757v81T15NpIJ0dyYtK5yaAc41rS2Zm Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEkb62CjDbPohX0Rgp9AfbAGHVz0AFAl+IaMUACgkQ9AfbAGHV z0CS9Af+PiQNr6bgJJpfOHrYf3fTm4+qxu6g1Bh6NNcIrQT+eilPyg+ycyT/55J1 zzldFFZxdlM0xUjFWdFyIKdYWeVujn1+ZkaYF6rqYP937jXFSc0JnFHBhR7+tftY vhP5tnmMPCrBpIt7gdPWz35xmcUMzgrbUqqXUbafyTcRViADnXVn9DaowiRYPQjv kr1FRT/blLgWFt3DJoyVumj2hqlYOV+wgTFdFej0oamKPsK1Lf2moS/um5V//kWj M3iUqL1/whfLBjzSCM/ivevoi1qDxGUxRTMjQZ3ABSIVi5yEQ7M1LkRF6irEYo2T kEPHfaRjuRbnGC7DOFnfi5rDHWeWQA== =hxSX -----END PGP SIGNATURE----- --ql757v81T15NpIJ0dyYtK5yaAc41rS2Zm--