xfs: create a shadow rmap btree during realtime rmap repair

Create an in-memory btree of rmap records instead of an array.  This
enables us to do live record collection instead of freezing the fs.

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

2 files changed, 76 insertions, 0 deletions

diff --git a/fs/xfs/libxfs/xfs_rtrmap_btree.c b/fs/xfs/libxfs/xfs_rtrmap_btree.c
index a1584784991e..29de9bfbde20 100644
--- a/fs/xfs/libxfs/xfs_rtrmap_btree.c
+++ b/fs/xfs/libxfs/xfs_rtrmap_btree.c
@@ -18,6 +18,7 @@
 #include "xfs_alloc.h"
 #include "xfs_btree.h"
 #include "xfs_btree_staging.h"
+#include "xfs_btree_mem.h"
 #include "xfs_rmap.h"
 #include "xfs_rtrmap_btree.h"
 #include "xfs_trace.h"
@@ -499,6 +500,75 @@ xfs_rtrmapbt_stage_cursor(
 	return cur;
 }
 
+STATIC int
+xfs_rtrmapbt_get_mem_minrecs(
+	struct xfs_btree_cur	*cur,
+	int			level)
+{
+	return cur->bc_mp->m_rtrmap_mnr[level != 0];
+}
+
+STATIC int
+xfs_rtrmapbt_get_mem_maxrecs(
+	struct xfs_btree_cur	*cur,
+	int			level)
+{
+	return cur->bc_mp->m_rtrmap_mxr[level != 0];
+}
+
+static const struct xfs_btree_ops xfs_rtrmapbt_mem_ops = {
+	.rec_len		= sizeof(struct xfs_rtrmap_rec),
+	.key_len		= 2 * sizeof(struct xfs_rtrmap_key),
+
+	.dup_cursor		= xfs_btree_mem_dup_cursor,
+	.set_root		= xfs_btree_mem_set_root,
+	.alloc_block		= xfbtree_alloc_block,
+	.free_block		= xfbtree_free_block,
+	.get_minrecs		= xfs_rtrmapbt_get_mem_minrecs,
+	.get_maxrecs		= xfs_rtrmapbt_get_mem_maxrecs,
+	.init_key_from_rec	= xfs_rtrmapbt_init_key_from_rec,
+	.init_high_key_from_rec	= xfs_rtrmapbt_init_high_key_from_rec,
+	.init_rec_from_cur	= xfs_rtrmapbt_init_rec_from_cur,
+	.init_ptr_from_cur	= xfs_btree_mem_init_ptr_from_cur,
+	.key_diff		= xfs_rtrmapbt_key_diff,
+	.buf_ops		= &xfs_rtrmapbt_buf_ops,
+	.diff_two_keys		= xfs_rtrmapbt_diff_two_keys,
+	.keys_inorder		= xfs_rtrmapbt_keys_inorder,
+	.recs_inorder		= xfs_rtrmapbt_recs_inorder,
+};
+
+/* Create a cursor for an in-memory btree. */
+struct xfs_btree_cur *
+xfs_rtrmapbt_mem_cursor(
+	struct xfs_mount	*mp,
+	struct xfs_trans	*tp,
+	struct xfs_buf		*head_bp,
+	struct xfbtree		*xfbtree)
+{
+	struct xfs_btree_cur	*cur;
+
+	/* Overlapping btree; 2 keys per pointer. */
+	cur = xfs_btree_alloc_cursor(mp, tp, XFS_BTNUM_RTRMAP);
+	cur->bc_flags = XFS_BTREE_CRC_BLOCKS | XFS_BTREE_OVERLAPPING |
+			XFS_BTREE_LONG_PTRS | XFS_BTREE_IN_MEMORY;
+	cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_rmap_2);
+	cur->bc_ops = &xfs_rtrmapbt_mem_ops;
+	cur->bc_mem.xfbtree = xfbtree;
+	cur->bc_mem.head_bp = head_bp;
+	cur->bc_nlevels = xfs_btree_mem_head_nlevels(head_bp);
+
+	return cur;
+}
+
+struct xfbtree *
+xfs_rtrmapbt_mem_create(
+	struct xfs_mount	*mp,
+	const char		*name)
+{
+	return xfbtree_create(mp, XFS_BTNUM_RTRMAP, &xfs_rtrmapbt_buf_ops,
+			XFBTREE_CREATE_LONG_PTRS, name);
+}
+
 /*
  * Install a new rt reverse mapping btree root.  Caller is responsible for
  * invalidating and freeing the old btree blocks.
diff --git a/fs/xfs/libxfs/xfs_rtrmap_btree.h b/fs/xfs/libxfs/xfs_rtrmap_btree.h
index d1ae7bc1d7e8..40226138413f 100644
--- a/fs/xfs/libxfs/xfs_rtrmap_btree.h
+++ b/fs/xfs/libxfs/xfs_rtrmap_btree.h
@@ -193,4 +193,10 @@ struct xfs_imeta_end;
 int xfs_rtrmapbt_create(struct xfs_trans **tpp, struct xfs_imeta_end *ic,
 		struct xfs_inode **ipp);
 
+struct xfbtree;
+struct xfs_btree_cur *xfs_rtrmapbt_mem_cursor(struct xfs_mount *mp,
+		struct xfs_trans *tp, struct xfs_buf *mhead_bp,
+		struct xfbtree *xfbtree);
+struct xfbtree *xfs_rtrmapbt_mem_create(struct xfs_mount *mp, const char *name);
+
 #endif	/* __XFS_RTRMAP_BTREE_H__ */