From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58570) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W6QwL-0002W8-VE for qemu-devel@nongnu.org; Thu, 23 Jan 2014 15:31:59 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1W6QwC-0004oC-Tq for qemu-devel@nongnu.org; Thu, 23 Jan 2014 15:31:53 -0500 Received: from paradis.irqsave.net ([62.212.105.220]:48178) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W6QwC-0004nd-5z for qemu-devel@nongnu.org; Thu, 23 Jan 2014 15:31:44 -0500 From: =?UTF-8?q?Beno=C3=AEt=20Canet?= Date: Thu, 23 Jan 2014 21:31:36 +0100 Message-Id: <1390509099-695-6-git-send-email-benoit.canet@irqsave.net> In-Reply-To: <1390509099-695-1-git-send-email-benoit.canet@irqsave.net> References: <1390509099-695-1-git-send-email-benoit.canet@irqsave.net> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PATCH V6 5/8] block: Create authorizations mechanism for external snapshot and resize. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, famz@redhat.com, =?UTF-8?q?Beno=C3=AEt=20Canet?= , armbru@redhat.com, mreitz@redhat.com, stefanha@redhat.com From: Beno=C3=AEt Canet Signed-off-by: Benoit Canet --- block.c | 65 ++++++++++++++++++++++++++++++++++++++++-= ------ block/blkverify.c | 2 +- blockdev.c | 2 +- include/block/block.h | 20 +++++++-------- include/block/block_int.h | 12 ++++++--- 5 files changed, 77 insertions(+), 24 deletions(-) diff --git a/block.c b/block.c index e1bc732..3e0994b 100644 --- a/block.c +++ b/block.c @@ -5088,21 +5088,68 @@ int bdrv_amend_options(BlockDriverState *bs, QEMU= OptionParameter *options) return bs->drv->bdrv_amend_options(bs, options); } =20 -ExtSnapshotPerm bdrv_check_ext_snapshot(BlockDriverState *bs) +/* Used to recurse on single child block filters. + * Single child block filter will store their child in bs->file. + */ +bool bdrv_generic_is_first_non_filter(BlockDriverState *bs, + BlockDriverState *candidate) { - if (bs->drv->bdrv_check_ext_snapshot) { - return bs->drv->bdrv_check_ext_snapshot(bs); + if (!bs->drv) { + return false; + } + + if (!bs->drv->authorizations[BS_IS_A_FILTER]) { + if (bs =3D=3D candidate) { + return true; + } else { + return false; + } + } + + if (!bs->drv->authorizations[BS_FILTER_PASS_DOWN]) { + return false; } =20 - if (bs->file && bs->file->drv && bs->file->drv->bdrv_check_ext_snaps= hot) { - return bs->file->drv->bdrv_check_ext_snapshot(bs); + if (!bs->file) { + return false; + } + + return bdrv_recurse_is_first_non_filter(bs->file, candidate); +} + +bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs, + BlockDriverState *candidate) +{ + if (bs->drv && bs->drv->bdrv_recurse_is_first_non_filter) { + return bs->drv->bdrv_recurse_is_first_non_filter(bs, candidate); } =20 - /* external snapshots are allowed by default */ - return EXT_SNAPSHOT_ALLOWED; + return bdrv_generic_is_first_non_filter(bs, candidate); } =20 -ExtSnapshotPerm bdrv_check_ext_snapshot_forbidden(BlockDriverState *bs) +/* This function checks if the candidate is the first non filter bs down= it's + * bs chain. Since we don't have pointers to parents it explore all bs c= hains + * from the top. Some filters can choose not to pass down the recursion. + */ +bool bdrv_is_first_non_filter(BlockDriverState *candidate) { - return EXT_SNAPSHOT_FORBIDDEN; + BlockDriverState *bs; + + /* walk down the bs forest recursively */ + QTAILQ_FOREACH(bs, &bdrv_states, device_list) { + bool perm; + + if (!bs->file) { + continue; + } + + perm =3D bdrv_recurse_is_first_non_filter(bs->file, candidate); + + /* candidate is the first non filter */ + if (perm) { + return true; + } + } + + return false; } diff --git a/block/blkverify.c b/block/blkverify.c index a2e8f5f..cfcbcf4 100644 --- a/block/blkverify.c +++ b/block/blkverify.c @@ -404,7 +404,7 @@ static BlockDriver bdrv_blkverify =3D { .bdrv_aio_writev =3D blkverify_aio_writev, .bdrv_aio_flush =3D blkverify_aio_flush, =20 - .bdrv_check_ext_snapshot =3D bdrv_check_ext_snapshot_forbidden, + .authorizations =3D { true, false }, }; =20 static void bdrv_blkverify_init(void) diff --git a/blockdev.c b/blockdev.c index 3c27911..8f95c7f 100644 --- a/blockdev.c +++ b/blockdev.c @@ -1250,7 +1250,7 @@ static void external_snapshot_prepare(BlkTransactio= nState *common, } } =20 - if (bdrv_check_ext_snapshot(state->old_bs) !=3D EXT_SNAPSHOT_ALLOWED= ) { + if (!bdrv_is_first_non_filter(state->old_bs)) { error_set(errp, QERR_FEATURE_DISABLED, "snapshot"); return; } diff --git a/include/block/block.h b/include/block/block.h index b4a77e6..59d9f12 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -287,16 +287,16 @@ int bdrv_amend_options(BlockDriverState *bs_new, QE= MUOptionParameter *options); /* external snapshots */ =20 typedef enum { - EXT_SNAPSHOT_ALLOWED, - EXT_SNAPSHOT_FORBIDDEN, -} ExtSnapshotPerm; - -/* return EXT_SNAPSHOT_ALLOWED if external snapshot is allowed - * return EXT_SNAPSHOT_FORBIDDEN if external snapshot is forbidden - */ -ExtSnapshotPerm bdrv_check_ext_snapshot(BlockDriverState *bs); -/* helper used to forbid external snapshots like in blkverify */ -ExtSnapshotPerm bdrv_check_ext_snapshot_forbidden(BlockDriverState *bs); + BS_IS_A_FILTER, + BS_FILTER_PASS_DOWN, + BS_AUTHORIZATION_COUNT, +} BsAuthorization; + +bool bdrv_generic_is_first_non_filter(BlockDriverState *bs, + BlockDriverState *candidate); +bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs, + BlockDriverState *candidate); +bool bdrv_is_first_non_filter(BlockDriverState *candidate); =20 /* async block I/O */ typedef void BlockDriverDirtyHandler(BlockDriverState *bs, int64_t secto= r, diff --git a/include/block/block_int.h b/include/block/block_int.h index f3f518c..611a955 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -69,10 +69,16 @@ struct BlockDriver { const char *format_name; int instance_size; =20 - /* if not defined external snapshots are allowed - * future block filters will query their children to build the respo= nse + /* this table of boolean contains authorizations for the block opera= tions */ + bool authorizations[BS_AUTHORIZATION_COUNT]; + /* for snapshots complex block filter like Quorum can implement the + * following recursive callback instead of BS_IS_A_FILTER. + * It's purpose is to recurse on the filter children while calling + * bdrv_recurse_is_first_non_filter on them. + * For a sample implementation look in the future Quorum block filte= r. */ - ExtSnapshotPerm (*bdrv_check_ext_snapshot)(BlockDriverState *bs); + bool (*bdrv_recurse_is_first_non_filter)(BlockDriverState *bs, + BlockDriverState *candidate= ); =20 int (*bdrv_probe)(const uint8_t *buf, int buf_size, const char *file= name); int (*bdrv_probe_device)(const char *filename); --=20 1.8.3.2