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Tue, 28 May 2019 18:09:11 +0000 (UTC) To: Vladimir Sementsov-Ogievskiy , "qemu-block@nongnu.org" References: <20190410202033.28617-1-mreitz@redhat.com> <20190410202033.28617-4-mreitz@redhat.com> <5fd51d1a-c9a9-f310-a3a3-369b2c1c27d0@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: <283400db-a7bb-7952-d83a-c49a2936b01b@redhat.com> Date: Tue, 28 May 2019 20:09:09 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <5fd51d1a-c9a9-f310-a3a3-369b2c1c27d0@virtuozzo.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="dcEu0WeGa6Y6fryT7soaSROlvsnLARiTB" 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 [10.5.110.47]); Tue, 28 May 2019 18:09:12 +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 X-Content-Filtered-By: Mailman/MimeDel 2.1.21 Subject: Re: [Qemu-devel] [PATCH v4 03/11] block: Storage child access function X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 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) --dcEu0WeGa6Y6fryT7soaSROlvsnLARiTB From: Max Reitz To: Vladimir Sementsov-Ogievskiy , "qemu-block@nongnu.org" Cc: Kevin Wolf , "qemu-devel@nongnu.org" Message-ID: <283400db-a7bb-7952-d83a-c49a2936b01b@redhat.com> Subject: Re: [Qemu-devel] [PATCH v4 03/11] block: Storage child access function References: <20190410202033.28617-1-mreitz@redhat.com> <20190410202033.28617-4-mreitz@redhat.com> <5fd51d1a-c9a9-f310-a3a3-369b2c1c27d0@virtuozzo.com> In-Reply-To: <5fd51d1a-c9a9-f310-a3a3-369b2c1c27d0@virtuozzo.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 20.05.19 12:41, Vladimir Sementsov-Ogievskiy wrote: > 10.04.2019 23:20, Max Reitz wrote: >> For completeness' sake, add a function for accessing a node's storage >> child, too. For filters, this is their filtered child; for non-filter= s, >> this is bs->file. >> >> Some places are deliberately left unconverted: >> - BDS opening/closing functions where bs->file is handled specially >> (which is basically wrong, but at least simplifies probing) >> - bdrv_co_block_status_from_file(), because its name implies that it >> points to ->file >> - bdrv_snapshot_goto() in one places unrefs bs->file. Such a >> modification is not covered by this patch and is therefore just >> safeguarded by an additional assert(), but otherwise kept as-is. >> >> Signed-off-by: Max Reitz [...] >> --- a/block/snapshot.c >> +++ b/block/snapshot.c >=20 > [..] >=20 >> @@ -184,6 +186,7 @@ int bdrv_snapshot_goto(BlockDriverState *bs, >> Error **errp) >> { >> BlockDriver *drv =3D bs->drv; >> + BlockDriverState *storage_bs; >> int ret, open_ret; >> =20 >> if (!drv) { >> @@ -204,39 +207,40 @@ int bdrv_snapshot_goto(BlockDriverState *bs, >> return ret; >> } >> =20 >> - if (bs->file) { >> - BlockDriverState *file; >> + storage_bs =3D bdrv_storage_bs(bs); >> + if (storage_bs) { >> QDict *options =3D qdict_clone_shallow(bs->options); >> QDict *file_options; >> Error *local_err =3D NULL; >> =20 >> - file =3D bs->file->bs; >> /* Prevent it from getting deleted when detached from bs */ >> - bdrv_ref(file); >> + bdrv_ref(storage_bs); >> =20 >> qdict_extract_subqdict(options, &file_options, "file."); >> qobject_unref(file_options); >> - qdict_put_str(options, "file", bdrv_get_node_name(file)); >> + qdict_put_str(options, "file", bdrv_get_node_name(storage_bs)= ); >> =20 >> if (drv->bdrv_close) { >> drv->bdrv_close(bs); >> } >> + >> + assert(bs->file->bs =3D=3D storage_bs); >=20 > Hmm, but what save us from this assertion fail for backing-filters? Bef= ore your > patch it was unreachable for them. Or what I miss? Ha, good point. I simply missed this point. Yes, I need to check whether storage_bs is bs->file or bs->backing and then take the corresponding sub-QDict from bs->options. Max >> bdrv_unref_child(bs, bs->file); >> bs->file =3D NULL; >> =20 >> - ret =3D bdrv_snapshot_goto(file, snapshot_id, errp); >> + ret =3D bdrv_snapshot_goto(storage_bs, snapshot_id, errp); >> open_ret =3D drv->bdrv_open(bs, options, bs->open_flags, &lo= cal_err); >> qobject_unref(options); >> if (open_ret < 0) { >> - bdrv_unref(file); >> + bdrv_unref(storage_bs); >> bs->drv =3D NULL; >> /* A bdrv_snapshot_goto() error takes precedence */ >> error_propagate(errp, local_err); >> return ret < 0 ? ret : open_ret; >> } >> =20 >> - assert(bs->file->bs =3D=3D file); >> - bdrv_unref(file); >> + assert(bs->file->bs =3D=3D storage_bs); >> + bdrv_unref(storage_bs); >> return ret; >> } >> =20 >=20 >=20 >=20 --dcEu0WeGa6Y6fryT7soaSROlvsnLARiTB Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEkb62CjDbPohX0Rgp9AfbAGHVz0AFAlzteUUACgkQ9AfbAGHV z0CpWwgAuq0436qWbpi4UQBbSX/Xrfx67R2Vso6SZaloE8HoW28HUo2/4Jg2xpvZ JThc8q+i7vfwMegkwM/Fp/PmOyR+E63hnz5kVewzYvA2gxxNBi498TAHVpJ/NbCd xDNcsVKQQK8sPmRU7sv39Fl8glDB3VYyB4bpWZRelzTf53jfjP8YwAOIKaIdPT/u 8T7FKd9xbCQNNdbEjWX1Lo0uZMO24jVYbW5ak491Ns2IHIE9Vw5hOecQgue0HJKY fRQSYKJYusuDj54rta8W1E9v1Jvmz7OKZ8F0mZYMX3fo7hR/CUqPIViov6wMKHx+ OVSP2GnuxNmMU4148O7M2PjdPjm9Nw== =hNVS -----END PGP SIGNATURE----- --dcEu0WeGa6Y6fryT7soaSROlvsnLARiTB--