Commit 19dbecdc authored by Kevin Wolf's avatar Kevin Wolf
Browse files

qemu-io: Use bdrv_parse_cache_mode() in reopen_f() 



We must forbid changing the WCE flag in bdrv_reopen() in the same patch,
as otherwise the behaviour would change so that the flag takes
precedence over the explicitly specified option.

The correct value of the WCE flag depends on the BlockBackend user (e.g.
guest device) and isn't a decision that the QMP client makes, so this
change is what we want.

Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
Reviewed-by: default avatarMax Reitz <mreitz@redhat.com>
parent 04feb4a5

block.c

+6 −12
Original line number Diff line number Diff line
@@ -2028,18 +2028,12 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue, 


    update_flags_from_options(&reopen_state->flags, opts);



    /* If a guest device is attached, it owns WCE */

    if (reopen_state->bs->blk && blk_get_attached_dev(reopen_state->bs->blk)) {

    /* WCE is a BlockBackend level option, can't change it */

    bool old_wce = bdrv_enable_write_cache(reopen_state->bs);

    bool new_wce = (reopen_state->flags & BDRV_O_CACHE_WB);



    if (old_wce != new_wce) {

            error_setg(errp, "Cannot change cache.writeback: Device attached");

            ret = -EINVAL;

            goto error;

        }

    }

    if (!reopen_state->bs->blk && !(reopen_state->flags & BDRV_O_CACHE_WB)) {

        error_setg(errp, "Cannot disable cache.writeback: No BlockBackend");

        error_setg(errp, "Cannot change cache.writeback");

        ret = -EINVAL;

        goto error;

    }

qemu-io-cmds.c

+13 −1
Original line number Diff line number Diff line
@@ -2106,6 +2106,7 @@ static int reopen_f(BlockBackend *blk, int argc, char **argv) 
    QDict *opts;

    int c;

    int flags = bs->open_flags;

    bool writethrough = !blk_enable_write_cache(blk);



    BlockReopenQueue *brq;

    Error *local_err = NULL;
@@ -2113,7 +2114,7 @@ static int reopen_f(BlockBackend *blk, int argc, char **argv) 
    while ((c = getopt(argc, argv, "c:o:r")) != -1) {

        switch (c) {

        case 'c':

            if (bdrv_parse_cache_flags(optarg, &flags) < 0) {

            if (bdrv_parse_cache_mode(optarg, &flags, &writethrough) < 0) {

                error_report("Invalid cache option: %s", optarg);

                return 0;

            }
@@ -2138,14 +2139,25 @@ static int reopen_f(BlockBackend *blk, int argc, char **argv) 
        return qemuio_command_usage(&reopen_cmd);

    }



    if (writethrough != blk_enable_write_cache(blk) &&

        blk_get_attached_dev(blk))

    {

        error_report("Cannot change cache.writeback: Device attached");

        qemu_opts_reset(&reopen_opts);

        return 0;

    }



    qopts = qemu_opts_find(&reopen_opts, NULL);

    opts = qopts ? qemu_opts_to_qdict(qopts, NULL) : NULL;

    qemu_opts_reset(&reopen_opts);



    flags |= blk_enable_write_cache(blk) ? BDRV_O_CACHE_WB : 0;

    brq = bdrv_reopen_queue(NULL, bs, opts, flags);

    bdrv_reopen_multiple(brq, &local_err);

    if (local_err) {

        error_report_err(local_err);

    } else {

        blk_set_enable_write_cache(blk, !writethrough);

    }



    return 0;

tests/qemu-iotests/142

+1 −1
Original line number Diff line number Diff line
@@ -216,7 +216,7 @@ echo 
# BDS initialised with the json: pseudo-protocol, but still have it inherit

# options from its parent node.



hmp_cmds="qemu-io none0 \"reopen -o cache.writeback=off,cache.direct=on,cache.no-flush=on\"

hmp_cmds="qemu-io none0 \"reopen -o cache.direct=on,cache.no-flush=on\"

info block none0

info block image

info block blkdebug

tests/qemu-iotests/142.out

+1 −1
Original line number Diff line number Diff line
@@ -414,7 +414,7 @@ cache.no-flush=on on backing-file 


--- Change cache mode in parent, child has explicit option in JSON ---



    Cache mode:       writethrough, direct, ignore flushes

    Cache mode:       writeback, direct, ignore flushes

    Cache mode:       writeback, direct, ignore flushes

    Cache mode:       writeback, direct, ignore flushes

    Cache mode:       writeback, ignore flushes