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blockdev: Split up 'cache' option 

The old 'cache' option really encodes three different boolean flags into
a cache mode name, without providing all combinations. Make them three
separate options instead and translate the old option to the new ones
for drive_init().

The specific boolean options take precedence if the old cache option is
specified as well, so the following options are equivalent:

-drive file=x,cache=none,cache.no-flush=true
-drive file=x,cache.writeback=true,cache.direct=true,cache.no-flush=true

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
This commit is contained in:
Kevin Wolf 2013-07-18 16:31:25 +02:00
parent 0f227a9470
commit 29c4e2b50d
1 changed files with 47 additions and 10 deletions
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57
blockdev.c
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@ -452,12 +452,15 @@ static DriveInfo *blockdev_init(QemuOpts *all_opts,
}
}
bdrv_flags |= BDRV_O_CACHE_WB;
if ((buf = qemu_opt_get(opts, "cache")) != NULL) {
if (bdrv_parse_cache_flags(buf, &bdrv_flags) != 0) {
error_report("invalid cache option");
return NULL;
}
bdrv_flags = 0;
if (qemu_opt_get_bool(opts, "cache.writeback", true)) {
bdrv_flags |= BDRV_O_CACHE_WB;
}
if (qemu_opt_get_bool(opts, "cache.direct", false)) {
bdrv_flags |= BDRV_O_NOCACHE;
}
if (qemu_opt_get_bool(opts, "cache.no-flush", true)) {
bdrv_flags |= BDRV_O_NO_FLUSH;
}
#ifdef CONFIG_LINUX_AIO
@ -740,6 +743,8 @@ static void qemu_opt_rename(QemuOpts *opts, const char *from, const char *to)
DriveInfo *drive_init(QemuOpts *all_opts, BlockInterfaceType block_default_type)
{
const char *value;
/* Change legacy command line options into QMP ones */
qemu_opt_rename(all_opts, "iops", "throttling.iops-total");
qemu_opt_rename(all_opts, "iops_rd", "throttling.iops-read");
@ -751,6 +756,31 @@ DriveInfo *drive_init(QemuOpts *all_opts, BlockInterfaceType block_default_type)
qemu_opt_rename(all_opts, "readonly", "read-only");
value = qemu_opt_get(all_opts, "cache");
if (value) {
int flags = 0;
if (bdrv_parse_cache_flags(value, &flags) != 0) {
error_report("invalid cache option");
return NULL;
}
/* Specific options take precedence */
if (!qemu_opt_get(all_opts, "cache.writeback")) {
qemu_opt_set_bool(all_opts, "cache.writeback",
!!(flags & BDRV_O_CACHE_WB));
}
if (!qemu_opt_get(all_opts, "cache.direct")) {
qemu_opt_set_bool(all_opts, "cache.direct",
!!(flags & BDRV_O_NOCACHE));
}
if (!qemu_opt_get(all_opts, "cache.no-flush")) {
qemu_opt_set_bool(all_opts, "cache.no-flush",
!!(flags & BDRV_O_NO_FLUSH));
}
qemu_opt_unset(all_opts, "cache");
}
return blockdev_init(all_opts, block_default_type);
}
@ -1850,10 +1880,17 @@ QemuOptsList qemu_common_drive_opts = {
.type = QEMU_OPT_STRING,
.help = "discard operation (ignore/off, unmap/on)",
},{
.name = "cache",
.type = QEMU_OPT_STRING,
.help = "host cache usage (none, writeback, writethrough, "
"directsync, unsafe)",
.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,