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[Qemu-devel] [PATCH 06/20] block: Add driver-specific options for backin
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PATCH 06/20] block: Add driver-specific options for backing files |
Date: |
Mon, 22 Apr 2013 13:31:20 +0200 |
Options starting in "backing." are passed to the backing file now. If
you don't need to specify the filename for the backing file, you can add
it on the command line instead of in the image file:
$ qemu-nbd -t /tmp/test.img
$ qemu-img create -f qcow2 empty.qcow2 1G
$ qemu-system-x86_64 -drive file=empty.qcow2,backing.file.driver=nbd,\
backing.file.host=localhost
Note that this doesn't override the backing filename from the image. If
the image has one, this will fail because NBD doesn't want the options
and a filename at the same time.
Signed-off-by: Kevin Wolf <address@hidden>
Reviewed-by: Eric Blake <address@hidden>
---
block.c | 27 +++++++++++++++++++++++----
block/mirror.c | 2 +-
include/block/block.h | 2 +-
3 files changed, 25 insertions(+), 6 deletions(-)
diff --git a/block.c b/block.c
index bea47c4..f717e1a 100644
--- a/block.c
+++ b/block.c
@@ -845,18 +845,33 @@ fail:
return ret;
}
-int bdrv_open_backing_file(BlockDriverState *bs)
+/*
+ * Opens the backing file for a BlockDriverState if not yet open
+ *
+ * options is a QDict of options to pass to the block drivers, or NULL for an
+ * empty set of options. The reference to the QDict is transferred to this
+ * function (even on failure), so if the caller intends to reuse the
dictionary,
+ * it needs to use QINCREF() before calling bdrv_file_open.
+ */
+int bdrv_open_backing_file(BlockDriverState *bs, QDict *options)
{
char backing_filename[PATH_MAX];
int back_flags, ret;
BlockDriver *back_drv = NULL;
if (bs->backing_hd != NULL) {
+ QDECREF(options);
return 0;
}
+ /* NULL means an empty set of options */
+ if (options == NULL) {
+ options = qdict_new();
+ }
+
bs->open_flags &= ~BDRV_O_NO_BACKING;
- if (bs->backing_file[0] == '\0') {
+ if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) {
+ QDECREF(options);
return 0;
}
@@ -871,7 +886,8 @@ int bdrv_open_backing_file(BlockDriverState *bs)
/* backing files always opened read-only */
back_flags = bs->open_flags & ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT);
- ret = bdrv_open(bs->backing_hd, backing_filename, NULL,
+ ret = bdrv_open(bs->backing_hd,
+ *backing_filename ? backing_filename : NULL, options,
back_flags, back_drv);
if (ret < 0) {
bdrv_delete(bs->backing_hd);
@@ -1027,7 +1043,10 @@ int bdrv_open(BlockDriverState *bs, const char
*filename, QDict *options,
/* If there is a backing file, use it */
if ((flags & BDRV_O_NO_BACKING) == 0) {
- ret = bdrv_open_backing_file(bs);
+ QDict *backing_options;
+
+ extract_subqdict(options, &backing_options, "backing.");
+ ret = bdrv_open_backing_file(bs, backing_options);
if (ret < 0) {
goto close_and_fail;
}
diff --git a/block/mirror.c b/block/mirror.c
index a62ad86..8b07dec 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -507,7 +507,7 @@ static void mirror_complete(BlockJob *job, Error **errp)
MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
int ret;
- ret = bdrv_open_backing_file(s->target);
+ ret = bdrv_open_backing_file(s->target, NULL);
if (ret < 0) {
char backing_filename[PATH_MAX];
bdrv_get_full_backing_filename(s->target, backing_filename,
diff --git a/include/block/block.h b/include/block/block.h
index ebd9512..1251c5c 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -137,7 +137,7 @@ int bdrv_parse_cache_flags(const char *mode, int *flags);
int bdrv_parse_discard_flags(const char *mode, int *flags);
int bdrv_file_open(BlockDriverState **pbs, const char *filename,
QDict *options, int flags);
-int bdrv_open_backing_file(BlockDriverState *bs);
+int bdrv_open_backing_file(BlockDriverState *bs, QDict *options);
int bdrv_open(BlockDriverState *bs, const char *filename, QDict *options,
int flags, BlockDriver *drv);
BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
--
1.8.1.4
- [Qemu-devel] [PULL 00/20] Block patches, Kevin Wolf, 2013/04/22
- [Qemu-devel] [PATCH 03/20] qemu-img: do not zero-pad the compressed write buffer, Kevin Wolf, 2013/04/22
- [Qemu-devel] [PATCH 01/20] qcow2: allow sub-cluster compressed write to last cluster, Kevin Wolf, 2013/04/22
- [Qemu-devel] [PATCH 04/20] qemu-iotests: Fix _filter_qemu, Kevin Wolf, 2013/04/22
- [Qemu-devel] [PATCH 02/20] qcow: allow sub-cluster compressed write to last cluster, Kevin Wolf, 2013/04/22
- [Qemu-devel] [PATCH 06/20] block: Add driver-specific options for backing files,
Kevin Wolf <=
- [Qemu-devel] [PATCH 07/20] block: Enable filename option, Kevin Wolf, 2013/04/22
- [Qemu-devel] [PATCH 05/20] block: Fail gracefully when using a format driver on protocol level, Kevin Wolf, 2013/04/22
- [Qemu-devel] [PATCH 08/20] raw-posix: Use bdrv_open options instead of filename, Kevin Wolf, 2013/04/22
- [Qemu-devel] [PATCH 10/20] blkdebug: Use bdrv_open options instead of filename, Kevin Wolf, 2013/04/22
- [Qemu-devel] [PATCH 09/20] raw-win32: Use bdrv_open options instead of filename, Kevin Wolf, 2013/04/22
- [Qemu-devel] [PATCH 11/20] blkverify: Use bdrv_open options instead of filename, Kevin Wolf, 2013/04/22
- [Qemu-devel] [PATCH 13/20] gluster: Use bdrv_open options instead of filename, Kevin Wolf, 2013/04/22
- [Qemu-devel] [PATCH 15/20] rbd: Use bdrv_open options instead of filename, Kevin Wolf, 2013/04/22
- [Qemu-devel] [PATCH 12/20] curl: Use bdrv_open options instead of filename, Kevin Wolf, 2013/04/22
- [Qemu-devel] [PATCH 14/20] iscsi: Use bdrv_open options instead of filename, Kevin Wolf, 2013/04/22