diff options
| -rw-r--r-- | drivers/md/dm-linear.c | 1 | ||||
| -rw-r--r-- | drivers/md/dm-table.c | 19 | ||||
| -rw-r--r-- | drivers/md/dm.c | 15 | ||||
| -rw-r--r-- | drivers/md/dm.h | 1 | ||||
| -rw-r--r-- | include/linux/device-mapper.h | 7 |
5 files changed, 33 insertions, 10 deletions
diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c index 79fb53e..bfa107f 100644 --- a/drivers/md/dm-linear.c +++ b/drivers/md/dm-linear.c @@ -142,6 +142,7 @@ static struct target_type linear_target = { .status = linear_status, .ioctl = linear_ioctl, .merge = linear_merge, + .features = DM_TARGET_SUPPORTS_BARRIERS, }; int __init dm_linear_init(void) diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 04e5fd7..ebaaf72 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); diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 4882ce7..dd953b1 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -835,7 +835,11 @@ static int __split_bio(struct mapped_device *md, struct bio *bio) ci.map = dm_get_table(md); if (unlikely(!ci.map)) return -EIO; - + if (unlikely(bio_barrier(bio) && !dm_table_barrier_ok(ci.map))) { + dm_table_put(ci.map); + bio_endio(bio, -EOPNOTSUPP); + return 0; + } ci.md = md; ci.bio = bio; ci.io = alloc_io(md); @@ -919,15 +923,6 @@ static int dm_request(struct request_queue *q, struct bio *bio) struct mapped_device *md = q->queuedata; int cpu; - /* - * There is no use in forwarding any barrier request since we can't - * guarantee it is (or can be) handled by the targets correctly. - */ - if (unlikely(bio_barrier(bio))) { - bio_endio(bio, -EOPNOTSUPP); - return 0; - } - down_read(&md->io_lock); cpu = part_stat_lock(); diff --git a/drivers/md/dm.h b/drivers/md/dm.h index 0ade60c..5b5d08b 100644 --- a/drivers/md/dm.h +++ b/drivers/md/dm.h @@ -51,6 +51,7 @@ int dm_table_any_congested(struct dm_table *t, int bdi_bits); * To check the return value from dm_table_find_target(). */ #define dm_target_is_valid(t) ((t)->table) +int dm_table_barrier_ok(struct dm_table *t); /*----------------------------------------------------------------- * A registry of target types. diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h index c1ba76c..8209e08 100644 --- a/include/linux/device-mapper.h +++ b/include/linux/device-mapper.h @@ -112,7 +112,14 @@ void dm_put_device(struct dm_target *ti, struct dm_dev *d); /* * Information about a target type */ + +/* + * Target features + */ +#define DM_TARGET_SUPPORTS_BARRIERS 0x00000001 + struct target_type { + uint64_t features; const char *name; struct module *module; unsigned version[3]; |