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Fri, 14 Jun 2019 15:55:18 +0000 (UTC) Received: from dresden.str.redhat.com (unknown [10.40.205.125]) by smtp.corp.redhat.com (Postfix) with ESMTPS id BCA331001B37; Fri, 14 Jun 2019 15:55:16 +0000 (UTC) To: Vladimir Sementsov-Ogievskiy , "qemu-block@nongnu.org" References: <20190612221004.2317-1-mreitz@redhat.com> <20190612221004.2317-17-mreitz@redhat.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: <8f86527e-2d2b-81d8-95e3-d458113c70ba@redhat.com> Date: Fri, 14 Jun 2019 17:55:15 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="tQqEbk6d9Q4F66P4jNivH267S9rnQSE1r" X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.45]); Fri, 14 Jun 2019 15:55:18 +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 v5 16/42] block: Use child access functions when flushing 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 , "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) --tQqEbk6d9Q4F66P4jNivH267S9rnQSE1r Content-Type: multipart/mixed; boundary="w16PUQPZKF0GYbSTk1vlido4UwGpFx9qc"; protected-headers="v1" From: Max Reitz To: Vladimir Sementsov-Ogievskiy , "qemu-block@nongnu.org" Cc: "qemu-devel@nongnu.org" , Kevin Wolf Message-ID: <8f86527e-2d2b-81d8-95e3-d458113c70ba@redhat.com> Subject: Re: [PATCH v5 16/42] block: Use child access functions when flushing References: <20190612221004.2317-1-mreitz@redhat.com> <20190612221004.2317-17-mreitz@redhat.com> In-Reply-To: --w16PUQPZKF0GYbSTk1vlido4UwGpFx9qc Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 14.06.19 16:01, Vladimir Sementsov-Ogievskiy wrote: > 13.06.2019 1:09, Max Reitz wrote: >> If the driver does not support .bdrv_co_flush() so bdrv_co_flush() >> itself has to flush the children of the given node, it should not flus= h >> just bs->file->bs, but in fact both the child that stores data, and th= e >> one that stores metadata (if they are separate). >> >> In any case, the BLKDBG_EVENT() should be emitted on the primary child= , >> because that is where a blkdebug node would be if there is any. >> >> Signed-off-by: Max Reitz >> --- >> block/io.c | 21 ++++++++++++++++++--- >> 1 file changed, 18 insertions(+), 3 deletions(-) >> >> diff --git a/block/io.c b/block/io.c >> index 53aabf86b5..64408cf19a 100644 >> --- a/block/io.c >> +++ b/block/io.c >> @@ -2533,6 +2533,8 @@ static void coroutine_fn bdrv_flush_co_entry(voi= d *opaque) >> =20 >> int coroutine_fn bdrv_co_flush(BlockDriverState *bs) >> { >> + BdrvChild *primary_child =3D bdrv_primary_child(bs); >> + BlockDriverState *storage_bs, *metadata_bs; >> int current_gen; >> int ret =3D 0; >> =20 >> @@ -2562,7 +2564,7 @@ int coroutine_fn bdrv_co_flush(BlockDriverState = *bs) >> } >> =20 >> /* Write back cached data to the OS even with cache=3Dunsafe */ >> - BLKDBG_EVENT(bs->file, BLKDBG_FLUSH_TO_OS); >> + BLKDBG_EVENT(primary_child, BLKDBG_FLUSH_TO_OS); >> if (bs->drv->bdrv_co_flush_to_os) { >> ret =3D bs->drv->bdrv_co_flush_to_os(bs); >> if (ret < 0) { >> @@ -2580,7 +2582,7 @@ int coroutine_fn bdrv_co_flush(BlockDriverState = *bs) >> goto flush_parent; >> } >> =20 >> - BLKDBG_EVENT(bs->file, BLKDBG_FLUSH_TO_DISK); >> + BLKDBG_EVENT(primary_child, BLKDBG_FLUSH_TO_DISK); >> if (!bs->drv) { >> /* bs->drv->bdrv_co_flush() might have ejected the BDS >> * (even in case of apparent success) */ >> @@ -2625,7 +2627,20 @@ int coroutine_fn bdrv_co_flush(BlockDriverState= *bs) >> * in the case of cache=3Dunsafe, so there are no useless flushe= s. >> */ >> flush_parent: >> - ret =3D bs->file ? bdrv_co_flush(bs->file->bs) : 0; >> + storage_bs =3D bdrv_storage_bs(bs); >> + metadata_bs =3D bdrv_metadata_bs(bs); >> + >> + ret =3D 0; >> + if (storage_bs) { >> + ret =3D bdrv_co_flush(storage_bs); >> + } >> + if (metadata_bs && metadata_bs !=3D storage_bs) { >> + int ret_metadata =3D bdrv_co_flush(metadata_bs); >> + if (!ret) { >> + ret =3D ret_metadata; >> + } >> + } >> + >> out: >> /* Notify any pending flushes that we have completed */ >> if (ret =3D=3D 0) { >> >=20 > Hmm, I'm not sure that if in one driver we decided to store data and me= tadata separately, > we need to support flushing them both generic code.. If at some point q= cow2 decides store part > of metadata in third child, we will not flush it here too? >=20 > Should not we instead loop through children and flush all? And I'd s/fl= ush_parent/flush_children as > it is rather weird. That sounds good. Well, we only need to flush the ones the driver has taken a WRITE permission on, but yes. Max --w16PUQPZKF0GYbSTk1vlido4UwGpFx9qc-- --tQqEbk6d9Q4F66P4jNivH267S9rnQSE1r Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEkb62CjDbPohX0Rgp9AfbAGHVz0AFAl0Dw2MACgkQ9AfbAGHV z0BriQf+I+RqKlyGC7iQ/PJf1ORJ1lgOGRcV10MFuhWrm2lo0FvhuOvr5XbikWQf FRXKnJxmShgdZwxPGuVkrrjCcOdeKu0Bb3/C2+zoksHwQfTzUwMWB+Q5R0vDzY10 vpGA8o8UN/kX72xlFJABrodEP6GSpc3EaUU4QeSzUe2O3LFUV91Dvr+EexITjsJq 6Yh85UKOO/E7H3jB/Cv2TvkA71VmIow+7G0FqLvGWOQ8n/9qzWZICFnDV46vv9ur ywGSDDMc2aN2ts7nmWsSlRMOykCn5vVxT1yXnbzw0R90IwrGPv9LNtxV+1WaUbaL cSnISikwo31LRDIihIC51h4tZ//JdA== =gbKy -----END PGP SIGNATURE----- --tQqEbk6d9Q4F66P4jNivH267S9rnQSE1r--