libceph: striping framework implementation

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

include/linux/ceph/striper.h

@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_CEPH_STRIPER_H
+#define _LINUX_CEPH_STRIPER_H
+
+#include <linux/list.h>
+#include <linux/types.h>
+
+struct ceph_file_layout;
+
+struct ceph_object_extent {
+	struct list_head oe_item;
+	u64 oe_objno;
+	u64 oe_off;
+	u64 oe_len;
+};
+
+static inline void ceph_object_extent_init(struct ceph_object_extent *ex)
+{
+	INIT_LIST_HEAD(&ex->oe_item);
+}
+
+/*
+ * Called for each mapped stripe unit.
+ *
+ * @bytes: number of bytes mapped, i.e. the minimum of the full length
+ *         requested (file extent length) or the remainder of the stripe
+ *         unit within an object
+ */
+typedef void (*ceph_object_extent_fn_t)(struct ceph_object_extent *ex,
+					u32 bytes, void *arg);
+
+int ceph_file_to_extents(struct ceph_file_layout *l, u64 off, u64 len,
+			 struct list_head *object_extents,
+			 struct ceph_object_extent *alloc_fn(void *arg),
+			 void *alloc_arg,
+			 ceph_object_extent_fn_t action_fn,
+			 void *action_arg);
+int ceph_iterate_extents(struct ceph_file_layout *l, u64 off, u64 len,
+			 struct list_head *object_extents,
+			 ceph_object_extent_fn_t action_fn,
+			 void *action_arg);
+
+struct ceph_file_extent {
+	u64 fe_off;
+	u64 fe_len;
+};
+
+static inline u64 ceph_file_extents_bytes(struct ceph_file_extent *file_extents,
+					  u32 num_file_extents)
+{
+	u64 bytes = 0;
+	u32 i;
+
+	for (i = 0; i < num_file_extents; i++)
+		bytes += file_extents[i].fe_len;
+
+	return bytes;
+}
+
+int ceph_extent_to_file(struct ceph_file_layout *l,
+			u64 objno, u64 objoff, u64 objlen,
+			struct ceph_file_extent **file_extents,
+			u32 *num_file_extents);
+
+#endif