From 5365f44dfa4669a8d37ec309c421c7512959d509 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Mon, 16 Nov 2015 15:34:59 +0100 Subject: [PATCH] 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: Kevin Wolf Reviewed-by: Max Reitz Reviewed-by: Alberto Garcia --- block/qcow2.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ include/block/block_int.h | 1 + 2 files changed, 48 insertions(+) diff --git a/block/qcow2.c b/block/qcow2.c index 5b59fa3..fda1562 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -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, diff --git a/include/block/block_int.h b/include/block/block_int.h index 66e208d..c2ce965 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -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); -- 2.7.4