[RFC PATCH 6/9] dm: add method to provision space

Brian Foster
2016-03-17T14:30:42Z

Signed-off-by: Brian Foster <bfoster@redhat.com>
---
drivers/md/dm.c | 35 +++++++++++++++++++++++++++++++++++
include/linux/device-mapper.h | 2 ++
2 files changed, 37 insertions(+)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 4da5d3e..e1aec28 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -737,6 +737,40 @@ out:
return r;
}

+static int dm_blk_provision_space(struct block_device *bdev,
+ sector_t offset, sector_t len)
+{
+ struct mapped_device *md = bdev->bd_disk->private_data;
+ int srcu_idx;
+ struct dm_table *map;
+ struct dm_target *tgt;
+ int r = -EINVAL;
+
+ map = dm_get_live_table(md, &srcu_idx);
+
+ if (!map || !dm_table_get_size(map))
+ goto out;
+
+ /* We only support devices that have a single target */
+ if (dm_table_get_num_targets(map) != 1)
+ goto out;
+
+ tgt = dm_table_get_target(map, 0);
+ if (!tgt->type->provision_space)
+ goto out;
+
+ if (dm_suspended_md(md)) {
+ r = -EAGAIN;
+ goto out;
+ }
+
+ r = tgt->type->provision_space(tgt, offset, len);
+out:
+ dm_put_live_table(md, srcu_idx);
+
+ return r;
+}
+
static struct dm_io *alloc_io(struct mapped_device *md)
{
return mempool_alloc(md->io_pool, GFP_NOIO);
@@ -3798,6 +3832,7 @@ static const struct block_device_operations dm_blk_dops = {
.pr_ops = &dm_pr_ops,
.reserve_space = dm_blk_reserve_space,
.get_reserved_space = dm_blk_get_reserved_space,
+ .provision_space = dm_blk_provision_space,
.owner = THIS_MODULE
};

diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 540c772..0ebf172 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -118,6 +118,7 @@ typedef int (*dm_busy_fn) (struct dm_target *ti);

typedef int (*dm_reserve_space_fn) (struct dm_target *ti, sector_t nr_sects);
typedef int (*dm_get_reserved_space_fn) (struct dm_target *ti, sector_t *nr_sects);
+typedef int (*dm_provision_space_fn) (struct dm_target *ti, sector_t offset, sector_t len);

void dm_error(const char *message);

@@ -167,6 +168,7 @@ struct target_type {
dm_io_hints_fn io_hints;
dm_reserve_space_fn reserve_space;
dm_get_reserved_space_fn get_reserved_space;
+ dm_provision_space_fn provision_space;

/* For internal device-mapper use. */
struct list_head list;