block: add an API for Persistent Reservations
This commits adds a driver API and ioctls for controlling Persistent
Reservations s/genericly/generically/ at the block layer. Persistent
Reservations are supported by SCSI and NVMe and allow controlling who gets
access to a device in a shared storage setup.
Note that we add a pr_ops structure to struct block_device_operations
instead of adding the members directly to avoid bloating all instances
of devices that will never support Persistent Reservations.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/include/linux/pr.h b/include/linux/pr.h
new file mode 100644
index 0000000..65c01c1
--- /dev/null
+++ b/include/linux/pr.h
@@ -0,0 +1,18 @@
+#ifndef LINUX_PR_H
+#define LINUX_PR_H
+
+#include <uapi/linux/pr.h>
+
+struct pr_ops {
+ int (*pr_register)(struct block_device *bdev, u64 old_key, u64 new_key,
+ u32 flags);
+ int (*pr_reserve)(struct block_device *bdev, u64 key,
+ enum pr_type type, u32 flags);
+ int (*pr_release)(struct block_device *bdev, u64 key,
+ enum pr_type type);
+ 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);
+};
+
+#endif /* LINUX_PR_H */