diff options
Diffstat (limited to 'drivers/md/dm-table.c')
| -rw-r--r-- | drivers/md/dm-table.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 04e5fd742c2c..ebaaf72cd822 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -38,6 +38,8 @@ struct dm_table { sector_t *highs; struct dm_target *targets; + unsigned barriers_supported:1; + /* * Indicates the rw permissions for the new logical * device. This should be a combination of FMODE_READ @@ -227,6 +229,7 @@ int dm_table_create(struct dm_table **result, fmode_t mode, INIT_LIST_HEAD(&t->devices); atomic_set(&t->holders, 1); + t->barriers_supported = 1; if (!num_targets) num_targets = KEYS_PER_NODE; @@ -728,6 +731,10 @@ int dm_table_add_target(struct dm_table *t, const char *type, /* FIXME: the plan is to combine high here and then have * the merge fn apply the target level restrictions. */ combine_restrictions_low(&t->limits, &tgt->limits); + + if (!(tgt->type->features & DM_TARGET_SUPPORTS_BARRIERS)) + t->barriers_supported = 0; + return 0; bad: @@ -772,6 +779,12 @@ int dm_table_complete(struct dm_table *t) check_for_valid_limits(&t->limits); + /* + * We only support barriers if there is exactly one underlying device. + */ + if (!list_is_singular(&t->devices)) + t->barriers_supported = 0; + /* how many indexes will the btree have ? */ leaf_nodes = dm_div_up(t->num_targets, KEYS_PER_NODE); t->depth = 1 + int_log(leaf_nodes, CHILDREN_PER_NODE); @@ -986,6 +999,12 @@ struct mapped_device *dm_table_get_md(struct dm_table *t) return t->md; } +int dm_table_barrier_ok(struct dm_table *t) +{ + return t->barriers_supported; +} +EXPORT_SYMBOL(dm_table_barrier_ok); + EXPORT_SYMBOL(dm_vcalloc); EXPORT_SYMBOL(dm_get_device); EXPORT_SYMBOL(dm_put_device); |