[v6,01/18] block: Add PR callouts for read keys and reservation

Commit Message

Mike Christie April 7, 2023, 8:05 p.m. UTC

Add callouts for reading keys and reservations. This allows LIO to support
the READ_KEYS and READ_RESERVATION commands so it can export devices to
VMs for software like windows clustering.

Signed-off-by: Mike Christie <[e-mail]>
Reviewed-by: Chaitanya Kulkarni <[e-mail]>
Reviewed-by: Christoph Hellwig <[e-mail]>
Reviewed-by: Bart Van Assche <[e-mail]>
---
 include/linux/pr.h | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

Comments

Hannes Reinecke April 11, 2023, 7:09 a.m. UTC | #1

On 4/7/23 22:05, Mike Christie wrote:
> Add callouts for reading keys and reservations. This allows LIO to support
> the READ_KEYS and READ_RESERVATION commands so it can export devices to
> VMs for software like windows clustering.
> 
> Signed-off-by: Mike Christie <[e-mail]>
> Reviewed-by: Chaitanya Kulkarni <[e-mail]>
> Reviewed-by: Christoph Hellwig <[e-mail]>
> Reviewed-by: Bart Van Assche <[e-mail]>
> ---
>   include/linux/pr.h | 25 +++++++++++++++++++++++++
>   1 file changed, 25 insertions(+)
> 
Reviewed-by: Hannes Reinecke <[e-mail]>

Cheers,

Hannes

Patch

diff --git a/include/linux/pr.h b/include/linux/pr.h
index 94ceec713afe..3003daec28a5 100644
--- a/include/linux/pr.h
+++ b/include/linux/pr.h
@@ -4,6 +4,18 @@ 
 
 #include <uapi/linux/pr.h>
 
+struct pr_keys {
+	u32	generation;
+	u32	num_keys;
+	u64	keys[];
+};
+
+struct pr_held_reservation {
+	u64		key;
+	u32		generation;
+	enum pr_type	type;
+};
+
 struct pr_ops {
 	int (*pr_register)(struct block_device *bdev, u64 old_key, u64 new_key,
 			u32 flags);
@@ -14,6 +26,19 @@  struct pr_ops {
 	int (*pr_preempt)(struct block_device *bdev, u64 old_key, u64 new_key,
 			enum pr_type type, bool abort);
 	int (*pr_clear)(struct block_device *bdev, u64 key);
+	/*
+	 * pr_read_keys - Read the registered keys and return them in the
+	 * pr_keys->keys array. The keys array will have been allocated at the
+	 * end of the pr_keys struct, and pr_keys->num_keys must be set to the
+	 * number of keys the array can hold. If there are more than can fit
+	 * in the array, success will still be returned and pr_keys->num_keys
+	 * will reflect the total number of keys the device contains, so the
+	 * caller can retry with a larger array.
+	 */
+	int (*pr_read_keys)(struct block_device *bdev,
+			struct pr_keys *keys_info);
+	int (*pr_read_reservation)(struct block_device *bdev,
+			struct pr_held_reservation *rsv);
 };
 
 #endif /* LINUX_PR_H */