From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50114) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dpavD-0005Yg-2V for qemu-devel@nongnu.org; Wed, 06 Sep 2017 10:03:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dpav7-0000tV-8O for qemu-devel@nongnu.org; Wed, 06 Sep 2017 10:03:15 -0400 From: Kevin Wolf Date: Wed, 6 Sep 2017 16:02:33 +0200 Message-Id: <20170906140246.7326-2-kwolf@redhat.com> In-Reply-To: <20170906140246.7326-1-kwolf@redhat.com> References: <20170906140246.7326-1-kwolf@redhat.com> Subject: [Qemu-devel] [PULL 01/14] block: pass bdrv_* methods to bs->file by default in block filters List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: kwolf@redhat.com, qemu-devel@nongnu.org From: Manos Pitsidianakis The following functions fail if bs->drv is a filter and does not implement them: bdrv_probe_blocksizes bdrv_probe_geometry bdrv_truncate bdrv_has_zero_init bdrv_get_info Instead, the call should be passed to bs->file if it exists, to allow filter drivers to support those methods without implementing them. This commit makes `drv->is_filter = true` imply that these callbacks will be forwarded to bs->file by default, so disabling support for these functions must be done explicitly. Reviewed-by: Eric Blake Reviewed-by: Stefan Hajnoczi Signed-off-by: Manos Pitsidianakis Signed-off-by: Kevin Wolf --- include/block/block_int.h | 6 +++++- block.c | 21 +++++++++++++++++++-- 2 files changed, 24 insertions(+), 3 deletions(-) diff --git a/include/block/block_int.h b/include/block/block_int.h index 7571c0aaaf..71183cc76e 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -87,7 +87,11 @@ struct BlockDriver { const char *format_name; int instance_size; - /* set to true if the BlockDriver is a block filter */ + /* set to true if the BlockDriver is a block filter. Block filters pass + * certain callbacks that refer to data (see block.c) to their bs->file if + * the driver doesn't implement them. Drivers that do not wish to forward + * must implement them and return -ENOTSUP. + */ bool is_filter; /* for snapshots block filter like Quorum can implement the * following recursive callback. diff --git a/block.c b/block.c index b749bd6404..175e8d35ff 100644 --- a/block.c +++ b/block.c @@ -496,6 +496,8 @@ int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz) if (drv && drv->bdrv_probe_blocksizes) { return drv->bdrv_probe_blocksizes(bs, bsz); + } else if (drv && drv->is_filter && bs->file) { + return bdrv_probe_blocksizes(bs->file->bs, bsz); } return -ENOTSUP; @@ -513,6 +515,8 @@ int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo) if (drv && drv->bdrv_probe_geometry) { return drv->bdrv_probe_geometry(bs, geo); + } else if (drv && drv->is_filter && bs->file) { + return bdrv_probe_geometry(bs->file->bs, geo); } return -ENOTSUP; @@ -3426,11 +3430,15 @@ int bdrv_truncate(BdrvChild *child, int64_t offset, PreallocMode prealloc, assert(child->perm & BLK_PERM_RESIZE); + /* if bs->drv == NULL, bs is closed, so there's nothing to do here */ if (!drv) { error_setg(errp, "No medium inserted"); return -ENOMEDIUM; } if (!drv->bdrv_truncate) { + if (bs->file && drv->is_filter) { + return bdrv_truncate(bs->file, offset, prealloc, errp); + } error_setg(errp, "Image format driver does not support resize"); return -ENOTSUP; } @@ -3767,6 +3775,9 @@ int bdrv_has_zero_init(BlockDriverState *bs) if (bs->drv->bdrv_has_zero_init) { return bs->drv->bdrv_has_zero_init(bs); } + if (bs->file && bs->drv->is_filter) { + return bdrv_has_zero_init(bs->file->bs); + } /* safe default */ return 0; @@ -3821,10 +3832,16 @@ void bdrv_get_backing_filename(BlockDriverState *bs, int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) { BlockDriver *drv = bs->drv; - if (!drv) + /* if bs->drv == NULL, bs is closed, so there's nothing to do here */ + if (!drv) { return -ENOMEDIUM; - if (!drv->bdrv_get_info) + } + if (!drv->bdrv_get_info) { + if (bs->file && drv->is_filter) { + return bdrv_get_info(bs->file->bs, bdi); + } return -ENOTSUP; + } memset(bdi, 0, sizeof(*bdi)); return drv->bdrv_get_info(bs, bdi); } -- 2.13.5