dm: remove limited barrier support

Prepare for full barrier implementation: first remove the restricted support.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
index bfa107f..79fb53e 100644 (file)
--- a/drivers/md/dm-linear.c
+++ b/drivers/md/dm-linear.c
@@ -142,7 +142,6 @@ 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 02d0b48..429b50b 100644 (file)
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -52,8 +52,6 @@ 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
@@ -243,7 +241,6 @@ int dm_table_create(struct dm_table **result, fmode_t mode,
 
        INIT_LIST_HEAD(&t->devices);
        atomic_set(&t->holders, 0);
-       t->barriers_supported = 1;
 
        if (!num_targets)
                num_targets = KEYS_PER_NODE;
@@ -751,10 +748,6 @@ 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:
@@ -799,12 +792,6 @@ 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);
@@ -1059,12 +1046,6 @@ 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 25d86e2..ab3b5d8 100644 (file)
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -851,11 +851,7 @@ static void __split_and_process_bio(struct mapped_device *md, struct bio *bio)
                bio_io_error(bio);
                return;
        }
-       if (unlikely(bio_barrier(bio) && !dm_table_barrier_ok(ci.map))) {
-               dm_table_put(ci.map);
-               bio_endio(bio, -EOPNOTSUPP);
-               return;
-       }
+
        ci.md = md;
        ci.bio = bio;
        ci.io = alloc_io(md);
@@ -937,6 +933,15 @@ 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 b48397c..a31506d 100644 (file)
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -52,7 +52,6 @@ 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 66ec05a..ded2d7c 100644 (file)
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -116,7 +116,6 @@ void dm_put_device(struct dm_target *ti, struct dm_dev *d);
 /*
  * Target features
  */
-#define DM_TARGET_SUPPORTS_BARRIERS 0x00000001
 
 struct target_type {
        uint64_t features;