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author | Max Reitz <mreitz@redhat.com> | 2015-02-05 13:58:11 -0500 |
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committer | Stefan Hajnoczi <stefanha@redhat.com> | 2015-02-16 15:07:18 +0000 |
commit | ca49a4fdb39d7b00b20e8500cba11aedc87755bd (patch) | |
tree | d609f7482ef9a1f6eda662e8be810250e140a898 /block | |
parent | 1ef01253eb90d0c69129c817e85fa92f9d45602a (diff) | |
download | hqemu-ca49a4fdb39d7b00b20e8500cba11aedc87755bd.zip hqemu-ca49a4fdb39d7b00b20e8500cba11aedc87755bd.tar.gz |
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 <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 1423162705-32065-3-git-send-email-mreitz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'block')
-rw-r--r-- | block/block-backend.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/block/block-backend.c b/block/block-backend.c index 7dc985c..d083b85 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); |