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block: Move cache options into options QDict

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This adds the cache mode options to the QDict, so that they can be
specified for child nodes (e.g. backing.cache.direct=off).

The cache modes are not removed from the flags at this point; instead,
options and flags are kept in sync. If the user specifies both flags and
options, the options take precedence.

Child node inherit cache modes as options now, they don't use flags any
more.

Note that this forbids specifying the cache mode for empty drives. It
didn't make sense anyway to specify it there, because it didn't have any
effect. blockdev_init() considers the cache options now bdrv_open()
options and therefore doesn't create an empty drive any more but calls
into bdrv_open(). This in turn will fail with no driver and filename
specified.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
Kevin Wolf 2015-05-08 17:49:53 +02:00
parent ccf9dc07b5
commit 91a097e747
2 changed files with 111 additions and 41 deletions
Download patch file Download diff file Expand all files Collapse all files

52
blockdev.c
View file

@ -387,16 +387,6 @@ static void extract_common_blockdev_options(QemuOpts *opts, int *bdrv_flags,
}
}
if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_WB, true)) {
*bdrv_flags |= BDRV_O_CACHE_WB;
}
if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_DIRECT, false)) {
*bdrv_flags |= BDRV_O_NOCACHE;
}
if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_NO_FLUSH, false)) {
*bdrv_flags |= BDRV_O_NO_FLUSH;
}
if ((aio = qemu_opt_get(opts, "aio")) != NULL) {
if (!strcmp(aio, "native")) {
*bdrv_flags |= BDRV_O_NATIVE_AIO;
@ -569,9 +559,7 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
}
if (snapshot) {
/* always use cache=unsafe with snapshot */
bdrv_flags &= ~BDRV_O_CACHE_MASK;
bdrv_flags |= (BDRV_O_SNAPSHOT|BDRV_O_CACHE_WB|BDRV_O_NO_FLUSH);
bdrv_flags |= BDRV_O_SNAPSHOT;
}
/* init */
@ -603,6 +591,20 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
file = NULL;
}
/* bdrv_open() defaults to the values in bdrv_flags (for compatibility
* with other callers) rather than what we want as the real defaults.
* Apply the defaults here instead. */
qdict_set_default_str(bs_opts, BDRV_OPT_CACHE_WB, "on");
qdict_set_default_str(bs_opts, BDRV_OPT_CACHE_DIRECT, "off");
qdict_set_default_str(bs_opts, BDRV_OPT_CACHE_NO_FLUSH, "off");
if (snapshot) {
/* always use cache=unsafe with snapshot */
qdict_put(bs_opts, BDRV_OPT_CACHE_WB, qstring_from_str("on"));
qdict_put(bs_opts, BDRV_OPT_CACHE_DIRECT, qstring_from_str("off"));
qdict_put(bs_opts, BDRV_OPT_CACHE_NO_FLUSH, qstring_from_str("on"));
}
blk = blk_new_open(qemu_opts_id(opts), file, NULL, bs_opts, bdrv_flags,
errp);
if (!blk) {
@ -3869,18 +3871,6 @@ QemuOptsList qemu_common_drive_opts = {
.name = "discard",
.type = QEMU_OPT_STRING,
.help = "discard operation (ignore/off, unmap/on)",
},{
.name = BDRV_OPT_CACHE_WB,
.type = QEMU_OPT_BOOL,
.help = "enables writeback mode for any caches",
},{
.name = BDRV_OPT_CACHE_DIRECT,
.type = QEMU_OPT_BOOL,
.help = "enables use of O_DIRECT (bypass the host page cache)",
},{
.name = BDRV_OPT_CACHE_NO_FLUSH,
.type = QEMU_OPT_BOOL,
.help = "ignore any flush requests for the device",
},{
.name = "aio",
.type = QEMU_OPT_STRING,
@ -3988,18 +3978,6 @@ static QemuOptsList qemu_root_bds_opts = {
.name = "discard",
.type = QEMU_OPT_STRING,
.help = "discard operation (ignore/off, unmap/on)",
},{
.name = "cache.writeback",
.type = QEMU_OPT_BOOL,
.help = "enables writeback mode for any caches",
},{
.name = "cache.direct",
.type = QEMU_OPT_BOOL,
.help = "enables use of O_DIRECT (bypass the host page cache)",
},{
.name = "cache.no-flush",
.type = QEMU_OPT_BOOL,
.help = "ignore any flush requests for the device",
},{
.name = "aio",
.type = QEMU_OPT_STRING,