From ca49a4fdb39d7b00b20e8500cba11aedc87755bd Mon Sep 17 00:00:00 2001 From: Max Reitz Date: Thu, 5 Feb 2015 13:58:11 -0500 Subject: [PATCH] block: Add blk_new_open() blk_new_with_bs() creates a BlockBackend with an empty BlockDriverState attached to it. Empty BDSs are not nice, therefore add an alternative function which combines blk_new_with_bs() with bdrv_open(). Note: In contrast to bdrv_open() which takes a BlockDriver parameter, blk_new_open() does not take such a parameter. This is because bdrv_open() opens a BlockDriverState, therefore it is natural to be able to set the BlockDriver for that BDS. The fact that bdrv_open() can open more than a single BDS is merely some form of a byproduct. blk_new_open() on the other hand is intended to be used to create a whole tree of BlockDriverStates. Therefore, setting a single BlockDriver does not make much sense. Instead, the drivers to be used for each of the nodes must be configured through the "options" QDict; including the driver of the root BDS. Signed-off-by: Max Reitz Reviewed-by: Eric Blake Reviewed-by: Kevin Wolf Message-id: 1423162705-32065-3-git-send-email-mreitz@redhat.com Signed-off-by: Stefan Hajnoczi --- block/block-backend.c | 34 ++++++++++++++++++++++++++++++++++ include/sysemu/block-backend.h | 3 +++ 2 files changed, 37 insertions(+) diff --git a/block/block-backend.c b/block/block-backend.c index 7dc985c070..d083b85bbe 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -91,6 +91,40 @@ BlockBackend *blk_new_with_bs(const char *name, Error **errp) return blk; } +/* + * Calls blk_new_with_bs() and then calls bdrv_open() on the BlockDriverState. + * + * Just as with bdrv_open(), after having called this function the reference to + * @options belongs to the block layer (even on failure). + * + * TODO: Remove @filename and @flags; it should be possible to specify a whole + * BDS tree just by specifying the @options QDict (or @reference, + * alternatively). At the time of adding this function, this is not possible, + * though, so callers of this function have to be able to specify @filename and + * @flags. + */ +BlockBackend *blk_new_open(const char *name, const char *filename, + const char *reference, QDict *options, int flags, + Error **errp) +{ + BlockBackend *blk; + int ret; + + blk = blk_new_with_bs(name, errp); + if (!blk) { + QDECREF(options); + return NULL; + } + + ret = bdrv_open(&blk->bs, filename, reference, options, flags, NULL, errp); + if (ret < 0) { + blk_unref(blk); + return NULL; + } + + return blk; +} + static void blk_delete(BlockBackend *blk) { assert(!blk->refcnt); diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h index 4ef0407536..2e8ebb2535 100644 --- a/include/sysemu/block-backend.h +++ b/include/sysemu/block-backend.h @@ -62,6 +62,9 @@ typedef struct BlockDevOps { BlockBackend *blk_new(const char *name, Error **errp); BlockBackend *blk_new_with_bs(const char *name, Error **errp); +BlockBackend *blk_new_open(const char *name, const char *filename, + const char *reference, QDict *options, int flags, + Error **errp); void blk_ref(BlockBackend *blk); void blk_unref(BlockBackend *blk); const char *blk_name(BlockBackend *blk);