xfs: introduce bitmap type for AG blocks

Create a typechecked bitmap for extents within an AG.  Online repair
uses bitmaps to store various different types of numbers, so let's make
it obvious when we're storing xfs_agblock_t (and later xfs_fsblock_t)
versus anything else.

In subsequent patches, we're going to use agblock bitmaps to enhance the
rmapbt checker to look for discrepancies between the rmapbt records and
AG metadata block usage.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

fs/xfs/scrub/bitmap.h

@@ -39,4 +39,52 @@ int xbitmap_walk_bits(struct xbitmap *bitmap, xbitmap_walk_bits_fn fn,
 
 bool xbitmap_empty(struct xbitmap *bitmap);
 
+/* Bitmaps, but for type-checked for xfs_agblock_t */
+
+struct xagb_bitmap {
+	struct xbitmap	agbitmap;
+};
+
+static inline void xagb_bitmap_init(struct xagb_bitmap *bitmap)
+{
+	xbitmap_init(&bitmap->agbitmap);
+}
+
+static inline void xagb_bitmap_destroy(struct xagb_bitmap *bitmap)
+{
+	xbitmap_destroy(&bitmap->agbitmap);
+}
+
+static inline int xagb_bitmap_clear(struct xagb_bitmap *bitmap,
+		xfs_agblock_t start, xfs_extlen_t len)
+{
+	return xbitmap_clear(&bitmap->agbitmap, start, len);
+}
+static inline int xagb_bitmap_set(struct xagb_bitmap *bitmap,
+		xfs_agblock_t start, xfs_extlen_t len)
+{
+	return xbitmap_set(&bitmap->agbitmap, start, len);
+}
+
+static inline int xagb_bitmap_disunion(struct xagb_bitmap *bitmap,
+		struct xagb_bitmap *sub)
+{
+	return xbitmap_disunion(&bitmap->agbitmap, &sub->agbitmap);
+}
+
+static inline uint32_t xagb_bitmap_hweight(struct xagb_bitmap *bitmap)
+{
+	return xbitmap_hweight(&bitmap->agbitmap);
+}
+static inline bool xagb_bitmap_empty(struct xagb_bitmap *bitmap)
+{
+	return xbitmap_empty(&bitmap->agbitmap);
+}
+
+static inline int xagb_bitmap_walk(struct xagb_bitmap *bitmap,
+		xbitmap_walk_fn fn, void *priv)
+{
+	return xbitmap_walk(&bitmap->agbitmap, fn, priv);
+}
+
 #endif	/* __XFS_SCRUB_BITMAP_H__ */

fs/xfs/scrub/repair.h

@@ -31,6 +31,7 @@ int xrep_init_btblock(struct xfs_scrub *sc, xfs_fsblock_t fsb,
 		const struct xfs_buf_ops *ops);
 
 struct xbitmap;
+struct xagb_bitmap;
 
 int xrep_fix_freelist(struct xfs_scrub *sc, bool can_shrink);
 int xrep_invalidate_blocks(struct xfs_scrub *sc, struct xbitmap *btlist);