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Thu, 1 Aug 2019 11:18:10 +0000 (UTC) Received: from dresden.str.redhat.com (ovpn-204-187.brq.redhat.com [10.40.204.187]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A45E25D9CA; Thu, 1 Aug 2019 11:18:06 +0000 (UTC) To: John Snow , Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org References: <20190730163251.755248-1-vsementsov@virtuozzo.com> <20190730163251.755248-2-vsementsov@virtuozzo.com> From: Max Reitz Openpgp: preference=signencrypt Autocrypt: addr=mreitz@redhat.com; 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: <9bb902a3-d2f2-6cf8-8adb-832ccbfde8f9@redhat.com> Date: Thu, 1 Aug 2019 13:18:04 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="nk4giPD5t25ciMiOS0KqhHpJMLMEthKjf" X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.41]); Thu, 01 Aug 2019 11:18:10 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH 1/3] block/backup: deal with zero detection 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: kwolf@redhat.com, den@openvz.org, armbru@redhat.com, qemu-devel@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) --nk4giPD5t25ciMiOS0KqhHpJMLMEthKjf Content-Type: multipart/mixed; boundary="JrFduQ5QF3aDtOxsnYXjBbMDzwmMeA1Qn"; protected-headers="v1" From: Max Reitz To: John Snow , Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org Cc: kwolf@redhat.com, armbru@redhat.com, qemu-devel@nongnu.org, den@openvz.org Message-ID: <9bb902a3-d2f2-6cf8-8adb-832ccbfde8f9@redhat.com> Subject: Re: [Qemu-devel] [PATCH 1/3] block/backup: deal with zero detection References: <20190730163251.755248-1-vsementsov@virtuozzo.com> <20190730163251.755248-2-vsementsov@virtuozzo.com> In-Reply-To: --JrFduQ5QF3aDtOxsnYXjBbMDzwmMeA1Qn Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 30.07.19 20:40, John Snow wrote: >=20 >=20 > On 7/30/19 12:32 PM, Vladimir Sementsov-Ogievskiy wrote: >> We have detect_zeroes option, so at least for blockdev-backup user >> should define it if zero-detection is needed. For drive-backup leave >> detection enabled by default but do it through existing option instead= >> of open-coding. >> >> Signed-off-by: Vladimir Sementsov-Ogievskiy = >> --- >> block/backup.c | 15 ++++++--------- >> blockdev.c | 8 ++++---- >> 2 files changed, 10 insertions(+), 13 deletions(-) >> >> diff --git a/block/backup.c b/block/backup.c >> index 715e1d3be8..f4aaf08df3 100644 >> --- a/block/backup.c >> +++ b/block/backup.c >> @@ -110,7 +110,10 @@ static int coroutine_fn backup_cow_with_bounce_bu= ffer(BackupBlockJob *job, >> BlockBackend *blk =3D job->common.blk; >> int nbytes; >> int read_flags =3D is_write_notifier ? BDRV_REQ_NO_SERIALISING : = 0; >> - int write_flags =3D job->serialize_target_writes ? BDRV_REQ_SERIA= LISING : 0; >> + int write_flags =3D >> + (job->serialize_target_writes ? BDRV_REQ_SERIALISING : 0)= | >> + (job->compress ? BDRV_REQ_WRITE_COMPRESSED : 0); >> + >> =20 >> assert(QEMU_IS_ALIGNED(start, job->cluster_size)); >> hbitmap_reset(job->copy_bitmap, start, job->cluster_size); >> @@ -128,14 +131,8 @@ static int coroutine_fn backup_cow_with_bounce_bu= ffer(BackupBlockJob *job, >> goto fail; >> } >> =20 >> - if (buffer_is_zero(*bounce_buffer, nbytes)) { >> - ret =3D blk_co_pwrite_zeroes(job->target, start, >> - nbytes, write_flags | BDRV_REQ_MAY= _UNMAP); >> - } else { >> - ret =3D blk_co_pwrite(job->target, start, >> - nbytes, *bounce_buffer, write_flags | >> - (job->compress ? BDRV_REQ_WRITE_COMPRESSE= D : 0)); >> - } >> + ret =3D blk_co_pwrite(job->target, start, nbytes, *bounce_buffer,= >> + write_flags); >> if (ret < 0) { >> trace_backup_do_cow_write_fail(job, start, ret); >> if (error_is_read) { >> diff --git a/blockdev.c b/blockdev.c >> index 4d141e9a1f..a94d754504 100644 >> --- a/blockdev.c >> +++ b/blockdev.c >> @@ -3434,7 +3434,7 @@ static BlockJob *do_drive_backup(DriveBackup *ba= ckup, JobTxn *txn, >> BlockJob *job =3D NULL; >> BdrvDirtyBitmap *bmap =3D NULL; >> AioContext *aio_context; >> - QDict *options =3D NULL; >> + QDict *options; >> Error *local_err =3D NULL; >> int flags, job_flags =3D JOB_DEFAULT; >> int64_t size; >> @@ -3529,10 +3529,10 @@ static BlockJob *do_drive_backup(DriveBackup *= backup, JobTxn *txn, >> goto out; >> } >> =20 >> + options =3D qdict_new(); >> + qdict_put_str(options, "discard", "unmap"); >> + qdict_put_str(options, "detect-zeroes", "unmap"); >> if (backup->format) { >> - if (!options) { >> - options =3D qdict_new(); >> - } >> qdict_put_str(options, "driver", backup->format); >> } >> =20 >> >=20 > I'm less sure of this one personally. Is it right to always try to set > unmap on the target? >=20 > I like the idea of removing special cases and handling things more > centrally though, but I'll want Max (or Kevin) to take a peek. I don=E2=80=99t quite know why, because this is just a block job specific= question and doesn=E2=80=99t have much to do with the rest of the block l= ayer, but OK. :-) drive-backup always set BDRV_REQ_MAY_UNMAP, as you can see. Maybe that didn=E2=80=99t do anything because the target wasn=E2=80=99t opened with = discard=3Dunmap. But to me, it=E2=80=99s clear that the intention was to indeed unmap the= areas in the target (it isn=E2=80=99t like the user had a choice of opening the= target with discard=3Dunmap or not). Max --JrFduQ5QF3aDtOxsnYXjBbMDzwmMeA1Qn-- --nk4giPD5t25ciMiOS0KqhHpJMLMEthKjf Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEkb62CjDbPohX0Rgp9AfbAGHVz0AFAl1CymwACgkQ9AfbAGHV z0C8NQf/aQW4RwXJqbQ4fXvtuX0EtXGr2qL2AXGceOlKyA/lysw6CUDI+ut1q9ST R6lmqPFTn5yFxxdhm9RAgFHNigL3vgNwtw2r3D1OtJdcNludQ2m1bzAFVPxDBbOm RxccGvnGp0GjXvZ4pDjog84pPr/MRMLL/YDApRo7l6T2uJNpK+3D3oSH9RGh3gt0 5Xy0A5SA23r5J4BZV03dmQ1RbzF/Ai01IJgoQzRHdWf4bUrbWHRW+0DWk3aPw0bh 0hLZKrujjmGWHal7hkQ7wdA3p5F/ar7NG8KxGJQuawQUmOmqXbmNCqkFT6eZf2Lb cdP420FaeT7OmLdZB7tZL8i1gETi6Q== =UtbT -----END PGP SIGNATURE----- --nk4giPD5t25ciMiOS0KqhHpJMLMEthKjf--