xfs: capture realtime CoW staging extents when rebuilding rt rmapbt

Walk the realtime refcount btree to find the CoW staging extents when
we're rebuilding the realtime rmap btree.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>

3 files changed, 130 insertions, 0 deletions

diff --git a/fs/xfs/scrub/bitmap.h b/fs/xfs/scrub/bitmap.h
index d59d5e76782c..29faf2b63715 100644
--- a/fs/xfs/scrub/bitmap.h
+++ b/fs/xfs/scrub/bitmap.h
@@ -111,6 +111,34 @@ int xagb_bitmap_set_btblocks(struct xagb_bitmap *bitmap,
 int xagb_bitmap_set_btcur_path(struct xagb_bitmap *bitmap,
 		struct xfs_btree_cur *cur);
 
+/* Bitmaps, but for type-checked for xfs_rgblock_t */
+
+struct xrgb_bitmap {
+	struct xbitmap	rgbitmap;
+};
+
+static inline void xrgb_bitmap_init(struct xrgb_bitmap *bitmap)
+{
+	xbitmap_init(&bitmap->rgbitmap);
+}
+
+static inline void xrgb_bitmap_destroy(struct xrgb_bitmap *bitmap)
+{
+	xbitmap_destroy(&bitmap->rgbitmap);
+}
+
+static inline int xrgb_bitmap_set(struct xrgb_bitmap *bitmap,
+		xfs_rgblock_t start, xfs_extlen_t len)
+{
+	return xbitmap_set(&bitmap->rgbitmap, start, len);
+}
+
+static inline int xrgb_bitmap_walk(struct xrgb_bitmap *bitmap,
+		xbitmap_walk_fn fn, void *priv)
+{
+	return xbitmap_walk(&bitmap->rgbitmap, fn, priv);
+}
+
 /* Bitmaps, but for type-checked for xfs_fsblock_t */
 
 struct xfsb_bitmap {
diff --git a/fs/xfs/scrub/repair.h b/fs/xfs/scrub/repair.h
index 44e0a69881c2..8f699b40a177 100644
--- a/fs/xfs/scrub/repair.h
+++ b/fs/xfs/scrub/repair.h
@@ -39,6 +39,7 @@ xrep_trans_commit(
 
 struct xbitmap;
 struct xagb_bitmap;
+struct xrgb_bitmap;
 struct xfsb_bitmap;
 
 int xrep_fix_freelist(struct xfs_scrub *sc, int alloc_flags);
diff --git a/fs/xfs/scrub/rtrmap_repair.c b/fs/xfs/scrub/rtrmap_repair.c
index 3fc8da37b0c2..d515b6c4472f 100644
--- a/fs/xfs/scrub/rtrmap_repair.c
+++ b/fs/xfs/scrub/rtrmap_repair.c
@@ -29,6 +29,7 @@
 #include "xfs_rtalloc.h"
 #include "xfs_ag.h"
 #include "xfs_rtgroup.h"
+#include "xfs_refcount.h"
 #include "scrub/xfs_scrub.h"
 #include "scrub/scrub.h"
 #include "scrub/common.h"
@@ -450,6 +451,99 @@ xrep_rtrmap_scan_ag(
 	return error;
 }
 
+struct xrep_rtrmap_stash_run {
+	struct xrep_rtrmap	*rr;
+	uint64_t		owner;
+};
+
+static int
+xrep_rtrmap_stash_run(
+	uint64_t			start,
+	uint64_t			len,
+	void				*priv)
+{
+	struct xrep_rtrmap_stash_run	*rsr = priv;
+	struct xrep_rtrmap		*rr = rsr->rr;
+	xfs_rgblock_t			rgbno = start;
+
+	return xrep_rtrmap_stash(rr, rgbno, len, rsr->owner, 0, 0);
+}
+
+/*
+ * Emit rmaps for every extent of bits set in the bitmap.  Caller must ensure
+ * that the ranges are in units of FS blocks.
+ */
+STATIC int
+xrep_rtrmap_stash_bitmap(
+	struct xrep_rtrmap		*rr,
+	struct xrgb_bitmap		*bitmap,
+	const struct xfs_owner_info	*oinfo)
+{
+	struct xrep_rtrmap_stash_run	rsr = {
+		.rr			= rr,
+		.owner			= oinfo->oi_owner,
+	};
+
+	return xrgb_bitmap_walk(bitmap, xrep_rtrmap_stash_run, &rsr);
+}
+
+/* Record a CoW staging extent. */
+STATIC int
+xrep_rtrmap_walk_cowblocks(
+	struct xfs_btree_cur		*cur,
+	const struct xfs_refcount_irec	*irec,
+	void				*priv)
+{
+	struct xrgb_bitmap		*bitmap = priv;
+
+	if (irec->rc_domain != XFS_RCDOM_COW || irec->rc_refcount != 1)
+		return -EFSCORRUPTED;
+
+	return xrgb_bitmap_set(bitmap, irec->rc_startblock,
+			irec->rc_blockcount);
+}
+
+/*
+ * Collect rmaps for the blocks containing the refcount btree, and all CoW
+ * staging extents.
+ */
+STATIC int
+xrep_rtrmap_find_refcount_rmaps(
+	struct xrep_rtrmap	*rr)
+{
+	struct xrgb_bitmap	cow_blocks;		/* COWBIT */
+	struct xfs_refcount_irec low = {
+		.rc_startblock	= 0,
+		.rc_domain	= XFS_RCDOM_COW,
+	};
+	struct xfs_refcount_irec high = {
+		.rc_startblock	= -1U,
+		.rc_domain	= XFS_RCDOM_COW,
+	};
+	struct xfs_scrub	*sc = rr->sc;
+	int			error;
+
+	if (!xfs_has_rtreflink(sc->mp))
+		return 0;
+
+	xrgb_bitmap_init(&cow_blocks);
+
+	/* Collect rmaps for CoW staging extents. */
+	error = xfs_refcount_query_range(sc->sr.refc_cur, &low, &high,
+			xrep_rtrmap_walk_cowblocks, &cow_blocks);
+	if (error)
+		goto out_bitmap;
+
+	/* Generate rmaps for everything. */
+	error = xrep_rtrmap_stash_bitmap(rr, &cow_blocks, &XFS_RMAP_OINFO_COW);
+	if (error)
+		goto out_bitmap;
+
+out_bitmap:
+	xrgb_bitmap_destroy(&cow_blocks);
+	return error;
+}
+
 /* Count and check all collected records. */
 STATIC int
 xrep_rtrmap_check_record(
@@ -497,6 +591,13 @@ xrep_rtrmap_find_rmaps(
 	if (error)
 		return error;
 
+	/* Find CoW staging extents. */
+	xrep_rtgroup_btcur_init(sc, &sc->sr);
+	error = xrep_rtrmap_find_refcount_rmaps(rr);
+	xchk_rtgroup_btcur_free(&sc->sr);
+	if (error)
+		return error;
+
 	/*
 	 * Set up for a potentially lengthy filesystem scan by reducing our
 	 * transaction resource usage for the duration.  Specifically: