[XFS] merge xfs_imap into xfs_dilocate

xfs_imap is the only caller of xfs_dilocate and doesn't add any significant
value.  Merge the two functions and document the various cases we have for
inode cluster lookup in the new xfs_imap.

Also remove the unused im_agblkno and im_ioffset fields from struct xfs_imap
while we're at it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Niv Sardi <xaiki@sgi.com>
diff --git a/fs/xfs/xfs_ialloc.h b/fs/xfs/xfs_ialloc.h
index ccf554a..50f558a 100644
--- a/fs/xfs/xfs_ialloc.h
+++ b/fs/xfs/xfs_ialloc.h
@@ -20,6 +20,7 @@
 
 struct xfs_buf;
 struct xfs_dinode;
+struct xfs_imap;
 struct xfs_mount;
 struct xfs_trans;
 
@@ -104,17 +105,14 @@
 	xfs_ino_t	*first_ino);	/* first inode in deleted cluster */
 
 /*
- * Return the location of the inode in bno/len/off,
- * for mapping it into a buffer.
+ * Return the location of the inode in imap, for mapping it into a buffer.
  */
 int
-xfs_dilocate(
+xfs_imap(
 	struct xfs_mount *mp,		/* file system mount structure */
 	struct xfs_trans *tp,		/* transaction pointer */
 	xfs_ino_t	ino,		/* inode to locate */
-	xfs_fsblock_t	*bno,		/* output: block containing inode */
-	int		*len,		/* output: num blocks in cluster*/
-	int		*off,		/* output: index in block of inode */
+	struct xfs_imap	*imap,		/* location map structure */
 	uint		flags);		/* flags for inode btree lookup */
 
 /*