Commit 29c4e2b5 authored by Kevin Wolf's avatar Kevin Wolf
Browse files

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: default avatarKevin Wolf <kwolf@redhat.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
parent 0f227a94

blockdev.c

+47 −10
Original line number Diff line number Diff line
@@ -452,12 +452,15 @@ static DriveInfo *blockdev_init(QemuOpts *all_opts, 
        }

    }



    bdrv_flags = 0;

    if (qemu_opt_get_bool(opts, "cache.writeback", true)) {

        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;

    }

    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,