[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_inode.c b/fs/xfs/xfs_inode.c
index 663ff9e..bf528b7 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -266,7 +266,7 @@
  * in once, thus we can use the mapping information stored in the inode
  * rather than calling xfs_imap().  This allows us to avoid the overhead
  * of looking at the inode btree for small block file systems
- * (see xfs_dilocate()).
+ * (see xfs_imap()).
  */
 int
 xfs_itobp(
@@ -2508,64 +2508,6 @@
 	ASSERT(ifp->if_bytes <= XFS_IFORK_SIZE(ip, whichfork));
 }
 
-
-
-
-/*
- * Map inode to disk block and offset.
- *
- * mp -- the mount point structure for the current file system
- * tp -- the current transaction
- * ino -- the inode number of the inode to be located
- * imap -- this structure is filled in with the information necessary
- *	 to retrieve the given inode from disk
- * flags -- flags to pass to xfs_dilocate indicating whether or not
- *	 lookups in the inode btree were OK or not
- */
-int
-xfs_imap(
-	xfs_mount_t	*mp,
-	xfs_trans_t	*tp,
-	xfs_ino_t	ino,
-	xfs_imap_t	*imap,
-	uint		flags)
-{
-	xfs_fsblock_t	fsbno;
-	int		len;
-	int		off;
-	int		error;
-
-	fsbno = imap->im_blkno ?
-		XFS_DADDR_TO_FSB(mp, imap->im_blkno) : NULLFSBLOCK;
-	error = xfs_dilocate(mp, tp, ino, &fsbno, &len, &off, flags);
-	if (error)
-		return error;
-
-	imap->im_blkno = XFS_FSB_TO_DADDR(mp, fsbno);
-	imap->im_len = XFS_FSB_TO_BB(mp, len);
-	imap->im_agblkno = XFS_FSB_TO_AGBNO(mp, fsbno);
-	imap->im_ioffset = (ushort)off;
-	imap->im_boffset = (ushort)(off << mp->m_sb.sb_inodelog);
-
-	/*
-	 * If the inode number maps to a block outside the bounds
-	 * of the file system then return NULL rather than calling
-	 * read_buf and panicing when we get an error from the
-	 * driver.
-	 */
-	if ((imap->im_blkno + imap->im_len) >
-	    XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks)) {
-		xfs_fs_cmn_err(CE_ALERT, mp, "xfs_imap: "
-			"(imap->im_blkno (0x%llx) + imap->im_len (0x%llx)) > "
-			" XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks) (0x%llx)",
-			(unsigned long long) imap->im_blkno,
-			(unsigned long long) imap->im_len,
-			XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks));
-		return EINVAL;
-	}
-	return 0;
-}
-
 void
 xfs_idestroy_fork(
 	xfs_inode_t	*ip,