On 5.09.23 11:59, Andrey Zhadchenko wrote:
Add new function to target_type, so any dm devices may realize it
Implement intermediate llseek_hole() on device-mapper layer, do some simple
checks.
Feature: dm: implement SEEK_HOLE for dm-qcow2 and dm-ploop
https://jira.vzint.dev/browse/PSBM-145746
Signed-off-by: Andrey Zhadchenko <andrey.zhadche...@virtuozzo.com>
---
v2: fix return and goto inconsistency
v3: normalize function assigments
drivers/md/dm.c | 41 +++++++++++++++++++++++++++++++++++
include/linux/device-mapper.h | 4 ++++
2 files changed, 45 insertions(+)
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 7e5c61a75eeb..8bdfd0d4eb96 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -484,6 +484,45 @@ static int dm_blk_ioctl(struct block_device *bdev, fmode_t
mode,
return r;
}
+static loff_t dm_llseek_hole(struct block_device *bdev, loff_t offset, int whence)
+{
+ struct mapped_device *md = bdev->bd_disk->private_data;
+ struct dm_table *table;
+ struct dm_target *ti;
+ int srcu_idx;
+ loff_t ret;
+
+ table = dm_get_live_table(md, &srcu_idx);
+ if (!table || !dm_table_get_size(table))
+ return -ENOTTY;
+
+ /*
+ * For now we only support devices that have a single target.
+ * But probably it is not hard to break it to a few requests to a
different
+ * targets
+ */
+ if (table->num_targets != 1)
+ return -EOPNOTSUPP;
+
+ ti = dm_table_get_target(table, 0);
+
+ if (dm_suspended_md(md)) {
+ ret = -EAGAIN;
+ goto out;
+ }
+
+ if (!ti->type->llseek_hole) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ ret = ti->type->llseek_hole(ti, offset, whence);
+
+out:
+ dm_put_live_table(md, srcu_idx);
+ return ret;
+}
+
u64 dm_start_time_ns_from_clone(struct bio *bio)
{
return jiffies_to_nsecs(clone_to_tio(bio)->io->start_time);
@@ -3255,6 +3294,7 @@ static const struct block_device_operations dm_blk_dops =
{
.getgeo = dm_blk_getgeo,
.report_zones = dm_blk_report_zones,
.pr_ops = &dm_pr_ops,
+ .llseek_hole = dm_llseek_hole,
.owner = THIS_MODULE
};
@@ -3264,6 +3304,7 @@ static const struct block_device_operations dm_rq_blk_dops = {
.ioctl = dm_blk_ioctl,
.getgeo = dm_blk_getgeo,
.pr_ops = &dm_pr_ops,
+ .llseek_hole = dm_llseek_hole,
.owner = THIS_MODULE
};
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 0e1f72680533..ddca72a1fac2 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -152,6 +152,9 @@ typedef size_t (*dm_dax_copy_iter_fn)(struct dm_target *ti,
pgoff_t pgoff,
typedef int (*dm_dax_zero_page_range_fn)(struct dm_target *ti, pgoff_t pgoff,
size_t nr_pages);
+typedef loff_t (*dm_llseek_hole_fn)(struct dm_target *ti, loff_t offset,
+ int whence);
+
void dm_error(const char *message);
struct dm_dev {
@@ -203,6 +206,7 @@ struct target_type {
dm_dax_copy_iter_fn dax_copy_from_iter;
dm_dax_copy_iter_fn dax_copy_to_iter;
dm_dax_zero_page_range_fn dax_zero_page_range;
+ dm_llseek_hole_fn llseek_hole;
/* For internal device-mapper use. */
struct list_head list;
LGTM
--
Regards,
Alexander Atanasov
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