Commit 5365f44d authored by Kevin Wolf's avatar Kevin Wolf
Browse files

qcow2: Add .bdrv_join_options callback 



qcow2 accepts a few driver-specific options that overlap semantically
(e.g. "overlap-check" is an alias of "overlap-check.template", and any
missing cache size option is derived from the given ones).

When bdrv_reopen() merges the set of updated options with left out
options that should be kept at their old value, we need to consider this
and filter out any duplicates (which would generally cause errors
because new and old value would contradict each other).

This patch adds a .bdrv_join_options callback to BlockDriver and
implements it for qcow2.

Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
Reviewed-by: default avatarMax Reitz <mreitz@redhat.com>
Reviewed-by: default avatarAlberto Garcia <berto@igalia.com>
parent 35cea223

block/qcow2.c

+47 −0
Original line number Diff line number Diff line
@@ -1282,6 +1282,52 @@ static void qcow2_reopen_abort(BDRVReopenState *state) 
    g_free(state->opaque);

}



static void qcow2_join_options(QDict *options, QDict *old_options)

{

    bool has_new_overlap_template =

        qdict_haskey(options, QCOW2_OPT_OVERLAP) ||

        qdict_haskey(options, QCOW2_OPT_OVERLAP_TEMPLATE);

    bool has_new_total_cache_size =

        qdict_haskey(options, QCOW2_OPT_CACHE_SIZE);

    bool has_all_cache_options;



    /* New overlap template overrides all old overlap options */

    if (has_new_overlap_template) {

        qdict_del(old_options, QCOW2_OPT_OVERLAP);

        qdict_del(old_options, QCOW2_OPT_OVERLAP_TEMPLATE);

        qdict_del(old_options, QCOW2_OPT_OVERLAP_MAIN_HEADER);

        qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L1);

        qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L2);

        qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_TABLE);

        qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK);

        qdict_del(old_options, QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE);

        qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L1);

        qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L2);

    }



    /* New total cache size overrides all old options */

    if (qdict_haskey(options, QCOW2_OPT_CACHE_SIZE)) {

        qdict_del(old_options, QCOW2_OPT_L2_CACHE_SIZE);

        qdict_del(old_options, QCOW2_OPT_REFCOUNT_CACHE_SIZE);

    }



    qdict_join(options, old_options, false);



    /*

     * If after merging all cache size options are set, an old total size is

     * overwritten. Do keep all options, however, if all three are new. The

     * resulting error message is what we want to happen.

     */

    has_all_cache_options =

        qdict_haskey(options, QCOW2_OPT_CACHE_SIZE) ||

        qdict_haskey(options, QCOW2_OPT_L2_CACHE_SIZE) ||

        qdict_haskey(options, QCOW2_OPT_REFCOUNT_CACHE_SIZE);



    if (has_all_cache_options && !has_new_total_cache_size) {

        qdict_del(options, QCOW2_OPT_CACHE_SIZE);

    }

}



static int64_t coroutine_fn qcow2_co_get_block_status(BlockDriverState *bs,

        int64_t sector_num, int nb_sectors, int *pnum)

{
@@ -3145,6 +3191,7 @@ BlockDriver bdrv_qcow2 = { 
    .bdrv_reopen_prepare  = qcow2_reopen_prepare,

    .bdrv_reopen_commit   = qcow2_reopen_commit,

    .bdrv_reopen_abort    = qcow2_reopen_abort,

    .bdrv_join_options    = qcow2_join_options,

    .bdrv_create        = qcow2_create,

    .bdrv_has_zero_init = bdrv_has_zero_init_1,

    .bdrv_co_get_block_status = qcow2_co_get_block_status,

include/block/block_int.h

+1 −0
Original line number Diff line number Diff line
@@ -121,6 +121,7 @@ struct BlockDriver { 
                               BlockReopenQueue *queue, Error **errp);

    void (*bdrv_reopen_commit)(BDRVReopenState *reopen_state);

    void (*bdrv_reopen_abort)(BDRVReopenState *reopen_state);

    void (*bdrv_join_options)(QDict *options, QDict *old_options);



    int (*bdrv_open)(BlockDriverState *bs, QDict *options, int flags,

                     Error **errp);