1 files changed, 133 insertions, 0 deletions
diff --git a/c_src/libbcachefs/backpointers.h b/c_src/libbcachefs/backpointers.h
new file mode 100644
index 00000000..737e2396
--- /dev/null
+++ b/c_src/libbcachefs/backpointers.h
@@ -0,0 +1,133 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _BCACHEFS_BACKPOINTERS_BACKGROUND_H
+#define _BCACHEFS_BACKPOINTERS_BACKGROUND_H
+
+#include "btree_iter.h"
+#include "btree_update.h"
+#include "buckets.h"
+#include "super.h"
+
+static inline u64 swab40(u64 x)
+{
+	return (((x & 0x00000000ffULL) << 32)|
+		((x & 0x000000ff00ULL) << 16)|
+		((x & 0x0000ff0000ULL) >>  0)|
+		((x & 0x00ff000000ULL) >> 16)|
+		((x & 0xff00000000ULL) >> 32));
+}
+
+int bch2_backpointer_invalid(struct bch_fs *, struct bkey_s_c k,
+			     enum bkey_invalid_flags, struct printbuf *);
+void bch2_backpointer_to_text(struct printbuf *, const struct bch_backpointer *);
+void bch2_backpointer_k_to_text(struct printbuf *, struct bch_fs *, struct bkey_s_c);
+void bch2_backpointer_swab(struct bkey_s);
+
+#define bch2_bkey_ops_backpointer ((struct bkey_ops) {	\
+	.key_invalid	= bch2_backpointer_invalid,	\
+	.val_to_text	= bch2_backpointer_k_to_text,	\
+	.swab		= bch2_backpointer_swab,	\
+	.min_val_size	= 32,				\
+})
+
+#define MAX_EXTENT_COMPRESS_RATIO_SHIFT		10
+
+/*
+ * Convert from pos in backpointer btree to pos of corresponding bucket in alloc
+ * btree:
+ */
+static inline struct bpos bp_pos_to_bucket(const struct bch_fs *c,
+					   struct bpos bp_pos)
+{
+	struct bch_dev *ca = bch_dev_bkey_exists(c, bp_pos.inode);
+	u64 bucket_sector = bp_pos.offset >> MAX_EXTENT_COMPRESS_RATIO_SHIFT;
+
+	return POS(bp_pos.inode, sector_to_bucket(ca, bucket_sector));
+}
+
+/*
+ * Convert from pos in alloc btree + bucket offset to pos in backpointer btree:
+ */
+static inline struct bpos bucket_pos_to_bp(const struct bch_fs *c,
+					   struct bpos bucket,
+					   u64 bucket_offset)
+{
+	struct bch_dev *ca = bch_dev_bkey_exists(c, bucket.inode);
+	struct bpos ret;
+
+	ret = POS(bucket.inode,
+		  (bucket_to_sector(ca, bucket.offset) <<
+		   MAX_EXTENT_COMPRESS_RATIO_SHIFT) + bucket_offset);
+
+	EBUG_ON(!bkey_eq(bucket, bp_pos_to_bucket(c, ret)));
+
+	return ret;
+}
+
+int bch2_bucket_backpointer_mod_nowritebuffer(struct btree_trans *, struct bpos bucket,
+				struct bch_backpointer, struct bkey_s_c, bool);
+
+static inline int bch2_bucket_backpointer_mod(struct btree_trans *trans,
+				struct bpos bucket,
+				struct bch_backpointer bp,
+				struct bkey_s_c orig_k,
+				bool insert)
+{
+	if (unlikely(bch2_backpointers_no_use_write_buffer))
+		return bch2_bucket_backpointer_mod_nowritebuffer(trans, bucket, bp, orig_k, insert);
+
+	struct bkey_i_backpointer bp_k;
+
+	bkey_backpointer_init(&bp_k.k_i);
+	bp_k.k.p = bucket_pos_to_bp(trans->c, bucket, bp.bucket_offset);
+	bp_k.v = bp;
+
+	if (!insert) {
+		bp_k.k.type = KEY_TYPE_deleted;
+		set_bkey_val_u64s(&bp_k.k, 0);
+	}
+
+	return bch2_trans_update_buffered(trans, BTREE_ID_backpointers, &bp_k.k_i);
+}
+
+static inline enum bch_data_type bkey_ptr_data_type(enum btree_id btree_id, unsigned level,
+						    struct bkey_s_c k, struct extent_ptr_decoded p)
+{
+	return  level		? BCH_DATA_btree :
+		p.has_ec	? BCH_DATA_stripe :
+				  BCH_DATA_user;
+}
+
+static inline void bch2_extent_ptr_to_bp(struct bch_fs *c,
+			   enum btree_id btree_id, unsigned level,
+			   struct bkey_s_c k, struct extent_ptr_decoded p,
+			   struct bpos *bucket_pos, struct bch_backpointer *bp)
+{
+	enum bch_data_type data_type = bkey_ptr_data_type(btree_id, level, k, p);
+	s64 sectors = level ? btree_sectors(c) : k.k->size;
+	u32 bucket_offset;
+
+	*bucket_pos = PTR_BUCKET_POS_OFFSET(c, &p.ptr, &bucket_offset);
+	*bp = (struct bch_backpointer) {
+		.btree_id	= btree_id,
+		.level		= level,
+		.data_type	= data_type,
+		.bucket_offset	= ((u64) bucket_offset << MAX_EXTENT_COMPRESS_RATIO_SHIFT) +
+			p.crc.offset,
+		.bucket_len	= ptr_disk_sectors(sectors, p),
+		.pos		= k.k->p,
+	};
+}
+
+int bch2_get_next_backpointer(struct btree_trans *, struct bpos, int,
+			      struct bpos *, struct bch_backpointer *, unsigned);
+struct bkey_s_c bch2_backpointer_get_key(struct btree_trans *, struct btree_iter *,
+					 struct bpos, struct bch_backpointer,
+					 unsigned);
+struct btree *bch2_backpointer_get_node(struct btree_trans *, struct btree_iter *,
+					struct bpos, struct bch_backpointer);
+
+int bch2_check_btree_backpointers(struct bch_fs *);
+int bch2_check_extents_to_backpointers(struct bch_fs *);
+int bch2_check_backpointers_to_extents(struct bch_fs *);
+
+#endif /* _BCACHEFS_BACKPOINTERS_BACKGROUND_H */