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[Qemu-devel] [PATCH 02/14] block: Add blk_new_open()
From: |
Max Reitz |
Subject: |
[Qemu-devel] [PATCH 02/14] block: Add blk_new_open() |
Date: |
Thu, 11 Dec 2014 14:20:41 +0100 |
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 naturally 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>
---
block/block-backend.c | 28 ++++++++++++++++++++++++++++
include/sysemu/block-backend.h | 3 +++
2 files changed, 31 insertions(+)
diff --git a/block/block-backend.c b/block/block-backend.c
index 42f97c0..2b19b0e 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -91,6 +91,34 @@ 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).
+ */
+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 38afa79..f39bb5c 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);
--
1.9.3
- [Qemu-devel] [PATCH 00/14] block: Remove "growable", add blk_new_open(), Max Reitz, 2014/12/11
- [Qemu-devel] [PATCH 02/14] block: Add blk_new_open(),
Max Reitz <=
- [Qemu-devel] [PATCH 04/14] block/xen: Use blk_new_open() in blk_connect(), Max Reitz, 2014/12/11
- [Qemu-devel] [PATCH 05/14] qemu-img: Use blk_new_open() in img_open(), Max Reitz, 2014/12/11
- [Qemu-devel] [PATCH 06/14] qemu-img: Use blk_new_open() in img_rebase(), Max Reitz, 2014/12/11
- [Qemu-devel] [PATCH 07/14] qemu-img: Use BlockBackend as far as possible, Max Reitz, 2014/12/11
- [Qemu-devel] [PATCH 10/14] qemu-io: Remove "growable" option, Max Reitz, 2014/12/11
- [Qemu-devel] [PATCH 08/14] qemu-nbd: Use blk_new_open() in main(), Max Reitz, 2014/12/11
- [Qemu-devel] [PATCH 11/14] qemu-io: Use BlockBackend, Max Reitz, 2014/12/11
- [Qemu-devel] [PATCH 13/14] block: Remove "growable" from BDS, Max Reitz, 2014/12/11