diff mbox series

[RFC,v13,13/20] dm: add finalize hook to target_type

Message ID 1709168102-7677-14-git-send-email-wufan@linux.microsoft.com
State New
Headers
Series Integrity Policy Enforcement LSM (IPE) |

Commit Message

Fan Wu Feb. 29, 2024, 12:54 a.m. UTC 
  This patch adds a target finalize hook.

The hook is triggered just before activating an inactive table of a
mapped device. If it returns an error the __bind get cancelled.

The dm-verity target will use this hook to attach the dm-verity's
roothash metadata to the block_device struct of the mapped device.

Signed-off-by: Fan Wu <wufan@linux.microsoft.com>

---
v1-v10:
  + Not present

v11:
  + Introduced

v12:
  + No changes

v13:
  + No changes
---
 drivers/md/dm.c               | 12 ++++++++++++
 include/linux/device-mapper.h |  7 +++++++
 2 files changed, 19 insertions(+)

Comments

Mike Snitzer March 2, 2024, 4:13 p.m. UTC | #1 
On Wed, Feb 28 2024 at  7:54P -0500,
Fan Wu <wufan@linux.microsoft.com> wrote:

> This patch adds a target finalize hook.
> 
> The hook is triggered just before activating an inactive table of a
> mapped device. If it returns an error the __bind get cancelled.
> 
> The dm-verity target will use this hook to attach the dm-verity's
> roothash metadata to the block_device struct of the mapped device.
> 
> Signed-off-by: Fan Wu <wufan@linux.microsoft.com>
> 
> ---
> v1-v10:
>   + Not present
> 
> v11:
>   + Introduced
> 
> v12:
>   + No changes
> 
> v13:
>   + No changes
> ---
>  drivers/md/dm.c               | 12 ++++++++++++
>  include/linux/device-mapper.h |  7 +++++++
>  2 files changed, 19 insertions(+)
> 
> diff --git a/drivers/md/dm.c b/drivers/md/dm.c
> index 8dcabf84d866..15b46edae49f 100644
> --- a/drivers/md/dm.c
> +++ b/drivers/md/dm.c
> @@ -2266,6 +2266,18 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
>  		goto out;
>  	}
>  
> +	for (unsigned int i = 0; i < t->num_targets; i++) {
> +		struct dm_target *ti = dm_table_get_target(t, i);
> +
> +		if (ti->type->finalize) {
> +			ret = ti->type->finalize(ti);
> +			if (ret) {
> +				old_map = ERR_PTR(ret);
> +				goto out;
> +			}
> +		}
> +	}
> +
>  	old_map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
>  	rcu_assign_pointer(md->map, (void *)t);
>  	md->immutable_target_type = dm_table_get_immutable_target_type(t);
> diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
> index 772ab4d74d94..627400b2d9af 100644
> --- a/include/linux/device-mapper.h
> +++ b/include/linux/device-mapper.h
> @@ -160,6 +160,12 @@ typedef int (*dm_dax_zero_page_range_fn)(struct dm_target *ti, pgoff_t pgoff,
>   */
>  typedef size_t (*dm_dax_recovery_write_fn)(struct dm_target *ti, pgoff_t pgoff,
>  		void *addr, size_t bytes, struct iov_iter *i);
> +/*
> + * Returns:
> + *  < 0 : error
> + *  = 0 : success
> + */
> +typedef int (*dm_finalize_fn) (struct dm_target *target);

This needs some documentation, e.g.: this hook allows DM targets in an
inactive table to complete their setup before the table is made
active.

Mike

>  
>  void dm_error(const char *message);
>  
> @@ -210,6 +216,7 @@ struct target_type {
>  	dm_dax_direct_access_fn direct_access;
>  	dm_dax_zero_page_range_fn dax_zero_page_range;
>  	dm_dax_recovery_write_fn dax_recovery_write;
> +	dm_finalize_fn finalize;
>  
>  	/* For internal device-mapper use. */
>  	struct list_head list;
> -- 
> 2.43.1
> 
>
diff mbox series

Patch

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 8dcabf84d866..15b46edae49f 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -2266,6 +2266,18 @@  static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
 		goto out;
 	}
 
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
+
+		if (ti->type->finalize) {
+			ret = ti->type->finalize(ti);
+			if (ret) {
+				old_map = ERR_PTR(ret);
+				goto out;
+			}
+		}
+	}
+
 	old_map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
 	rcu_assign_pointer(md->map, (void *)t);
 	md->immutable_target_type = dm_table_get_immutable_target_type(t);
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 772ab4d74d94..627400b2d9af 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -160,6 +160,12 @@  typedef int (*dm_dax_zero_page_range_fn)(struct dm_target *ti, pgoff_t pgoff,
  */
 typedef size_t (*dm_dax_recovery_write_fn)(struct dm_target *ti, pgoff_t pgoff,
 		void *addr, size_t bytes, struct iov_iter *i);
+/*
+ * Returns:
+ *  < 0 : error
+ *  = 0 : success
+ */
+typedef int (*dm_finalize_fn) (struct dm_target *target);
 
 void dm_error(const char *message);
 
@@ -210,6 +216,7 @@  struct target_type {
 	dm_dax_direct_access_fn direct_access;
 	dm_dax_zero_page_range_fn dax_zero_page_range;
 	dm_dax_recovery_write_fn dax_recovery_write;
+	dm_finalize_fn finalize;
 
 	/* For internal device-mapper use. */
 	struct list_head list;