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[Qemu-devel] [PULL v2 51/65] block: Add blk_new_open()
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PULL v2 51/65] block: Add blk_new_open() |
Date: |
Mon, 16 Feb 2015 15:46:16 +0000 |
From: Max Reitz <address@hidden>
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 <address@hidden>
Reviewed-by: Eric Blake <address@hidden>
Reviewed-by: Kevin Wolf <address@hidden>
Message-id: address@hidden
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
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 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);
diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h
index 4ef0407..2e8ebb2 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);
--
2.1.0
- [Qemu-devel] [PULL v2 44/65] qtest: Add scripts/qtest.py, (continued)
- [Qemu-devel] [PULL v2 44/65] qtest: Add scripts/qtest.py, Stefan Hajnoczi, 2015/02/16
- [Qemu-devel] [PULL v2 37/65] qtest/ahci: Assert sector size in identify test, Stefan Hajnoczi, 2015/02/16
- [Qemu-devel] [PULL v2 45/65] qemu-iotests: Add VM method qtest() to iotests.py, Stefan Hajnoczi, 2015/02/16
- [Qemu-devel] [PULL v2 46/65] qemu-iotests: Allow caller to disable underscore convertion for qmp, Stefan Hajnoczi, 2015/02/16
- [Qemu-devel] [PULL v2 47/65] qemu-iotests: Add 093 for IO throttling, Stefan Hajnoczi, 2015/02/16
- [Qemu-devel] [PULL v2 50/65] block: Lift some BDS functions to the BlockBackend, Stefan Hajnoczi, 2015/02/16
- [Qemu-devel] [PULL v2 49/65] iotests: Add test for qemu-img convert to NBD, Stefan Hajnoczi, 2015/02/16
- [Qemu-devel] [PULL v2 52/65] block: Add Error parameter to bdrv_find_protocol(), Stefan Hajnoczi, 2015/02/16
- [Qemu-devel] [PULL v2 53/65] iotests: Add test for driver=qcow2, format=qcow2, Stefan Hajnoczi, 2015/02/16
- [Qemu-devel] [PULL v2 48/65] qemu-img: Fix qemu-img convert -n, Stefan Hajnoczi, 2015/02/16
- [Qemu-devel] [PULL v2 51/65] block: Add blk_new_open(),
Stefan Hajnoczi <=
- [Qemu-devel] [PULL v2 56/65] qemu-img: Use blk_new_open() in img_open(), Stefan Hajnoczi, 2015/02/16
- [Qemu-devel] [PULL v2 54/65] blockdev: Use blk_new_open() in blockdev_init(), Stefan Hajnoczi, 2015/02/16
- [Qemu-devel] [PULL v2 57/65] qemu-img: Use blk_new_open() in img_rebase(), Stefan Hajnoczi, 2015/02/16
- [Qemu-devel] [PULL v2 55/65] block/xen: Use blk_new_open() in blk_connect(), Stefan Hajnoczi, 2015/02/16
- [Qemu-devel] [PULL v2 58/65] qemu-img: Use BlockBackend as far as possible, Stefan Hajnoczi, 2015/02/16
- [Qemu-devel] [PULL v2 59/65] qemu-nbd: Use blk_new_open() in main(), Stefan Hajnoczi, 2015/02/16
- [Qemu-devel] [PULL v2 63/65] block: Clamp BlockBackend requests, Stefan Hajnoczi, 2015/02/16
- [Qemu-devel] [PULL v2 61/65] qemu-io: Remove "growable" option, Stefan Hajnoczi, 2015/02/16
- [Qemu-devel] [PULL v2 60/65] qemu-io: Use blk_new_open() in openfile(), Stefan Hajnoczi, 2015/02/16
- [Qemu-devel] [PULL v2 62/65] qemu-io: Use BlockBackend, Stefan Hajnoczi, 2015/02/16