[PATCH 033/119] xfs: support overlapping intervals in the rmap btree

["Darrick J. Wong" <darrick.wong@oracle.com>]

Now that the generic btree code supports overlapping intervals, plug
in the rmap btree to this functionality.  We will need it to find
potential left neighbors in xfs_rmap_{alloc,free} later in the patch
set.

v2: Fix bit manipulation bug when generating high key offset.
v3: Move unwritten bit to rm_offset.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/libxfs/xfs_rmap_btree.c |   59 +++++++++++++++++++++++++++++++++++++++-
 fs/xfs/libxfs/xfs_rmap_btree.h |   10 +++++--
 2 files changed, 66 insertions(+), 3 deletions(-)


diff --git a/fs/xfs/libxfs/xfs_rmap_btree.c b/fs/xfs/libxfs/xfs_rmap_btree.c
index c50c725..9adb930 100644
--- a/fs/xfs/libxfs/xfs_rmap_btree.c
+++ b/fs/xfs/libxfs/xfs_rmap_btree.c
@@ -181,6 +181,28 @@ xfs_rmapbt_init_key_from_rec(
 }
 
 STATIC void
+xfs_rmapbt_init_high_key_from_rec(
+	union xfs_btree_key	*key,
+	union xfs_btree_rec	*rec)
+{
+	__uint64_t		off;
+	int			adj;
+
+	adj = be32_to_cpu(rec->rmap.rm_blockcount) - 1;
+
+	key->rmap.rm_startblock = rec->rmap.rm_startblock;
+	be32_add_cpu(&key->rmap.rm_startblock, adj);
+	key->rmap.rm_owner = rec->rmap.rm_owner;
+	key->rmap.rm_offset = rec->rmap.rm_offset;
+	if (XFS_RMAP_NON_INODE_OWNER(be64_to_cpu(rec->rmap.rm_owner)) ||
+	    XFS_RMAP_IS_BMBT_BLOCK(be64_to_cpu(rec->rmap.rm_offset)))
+		return;
+	off = be64_to_cpu(key->rmap.rm_offset);
+	off = (XFS_RMAP_OFF(off) + adj) | (off & ~XFS_RMAP_OFF_MASK);
+	key->rmap.rm_offset = cpu_to_be64(off);
+}
+
+STATIC void
 xfs_rmapbt_init_rec_from_cur(
 	struct xfs_btree_cur	*cur,
 	union xfs_btree_rec	*rec)
@@ -235,6 +257,38 @@ xfs_rmapbt_key_diff(
 	return 0;
 }
 
+STATIC __int64_t
+xfs_rmapbt_diff_two_keys(
+	struct xfs_btree_cur	*cur,
+	union xfs_btree_key	*k1,
+	union xfs_btree_key	*k2)
+{
+	struct xfs_rmap_key	*kp1 = &k1->rmap;
+	struct xfs_rmap_key	*kp2 = &k2->rmap;
+	__int64_t		d;
+	__u64			x, y;
+
+	d = (__int64_t)be32_to_cpu(kp2->rm_startblock) -
+		       be32_to_cpu(kp1->rm_startblock);
+	if (d)
+		return d;
+
+	x = be64_to_cpu(kp2->rm_owner);
+	y = be64_to_cpu(kp1->rm_owner);
+	if (x > y)
+		return 1;
+	else if (y > x)
+		return -1;
+
+	x = XFS_RMAP_OFF(be64_to_cpu(kp2->rm_offset));
+	y = XFS_RMAP_OFF(be64_to_cpu(kp1->rm_offset));
+	if (x > y)
+		return 1;
+	else if (y > x)
+		return -1;
+	return 0;
+}
+
 static bool
 xfs_rmapbt_verify(
 	struct xfs_buf		*bp)
@@ -350,6 +404,7 @@ xfs_rmapbt_recs_inorder(
 static const struct xfs_btree_ops xfs_rmapbt_ops = {
 	.rec_len		= sizeof(struct xfs_rmap_rec),
 	.key_len		= sizeof(struct xfs_rmap_key),
+	.flags			= XFS_BTREE_OPS_OVERLAPPING,
 
 	.dup_cursor		= xfs_rmapbt_dup_cursor,
 	.set_root		= xfs_rmapbt_set_root,
@@ -358,10 +413,12 @@ static const struct xfs_btree_ops xfs_rmapbt_ops = {
 	.get_minrecs		= xfs_rmapbt_get_minrecs,
 	.get_maxrecs		= xfs_rmapbt_get_maxrecs,
 	.init_key_from_rec	= xfs_rmapbt_init_key_from_rec,
+	.init_high_key_from_rec	= xfs_rmapbt_init_high_key_from_rec,
 	.init_rec_from_cur	= xfs_rmapbt_init_rec_from_cur,
 	.init_ptr_from_cur	= xfs_rmapbt_init_ptr_from_cur,
 	.key_diff		= xfs_rmapbt_key_diff,
 	.buf_ops		= &xfs_rmapbt_buf_ops,
+	.diff_two_keys		= xfs_rmapbt_diff_two_keys,
 #if defined(DEBUG) || defined(XFS_WARN)
 	.keys_inorder		= xfs_rmapbt_keys_inorder,
 	.recs_inorder		= xfs_rmapbt_recs_inorder,
@@ -410,7 +467,7 @@ xfs_rmapbt_maxrecs(
 	if (leaf)
 		return blocklen / sizeof(struct xfs_rmap_rec);
 	return blocklen /
-		(sizeof(struct xfs_rmap_key) + sizeof(xfs_rmap_ptr_t));
+		(2 * sizeof(struct xfs_rmap_key) + sizeof(xfs_rmap_ptr_t));
 }
 
 /* Compute the maximum height of an rmap btree. */
diff --git a/fs/xfs/libxfs/xfs_rmap_btree.h b/fs/xfs/libxfs/xfs_rmap_btree.h
index 17fa383..796071c 100644
--- a/fs/xfs/libxfs/xfs_rmap_btree.h
+++ b/fs/xfs/libxfs/xfs_rmap_btree.h
@@ -38,12 +38,18 @@ struct xfs_mount;
 #define XFS_RMAP_KEY_ADDR(block, index) \
 	((struct xfs_rmap_key *) \
 		((char *)(block) + XFS_RMAP_BLOCK_LEN + \
-		 ((index) - 1) * sizeof(struct xfs_rmap_key)))
+		 ((index) - 1) * 2 * sizeof(struct xfs_rmap_key)))
+
+#define XFS_RMAP_HIGH_KEY_ADDR(block, index) \
+	((struct xfs_rmap_key *) \
+		((char *)(block) + XFS_RMAP_BLOCK_LEN + \
+		 sizeof(struct xfs_rmap_key) + \
+		 ((index) - 1) * 2 * sizeof(struct xfs_rmap_key)))
 
 #define XFS_RMAP_PTR_ADDR(block, index, maxrecs) \
 	((xfs_rmap_ptr_t *) \
 		((char *)(block) + XFS_RMAP_BLOCK_LEN + \
-		 (maxrecs) * sizeof(struct xfs_rmap_key) + \
+		 (maxrecs) * 2 * sizeof(struct xfs_rmap_key) + \
 		 ((index) - 1) * sizeof(xfs_rmap_ptr_t)))
 
 struct xfs_btree_cur *xfs_rmapbt_init_cursor(struct xfs_mount *mp,