xfs: Start using pquotaino from the superblock.

Start using pquotino and define a macro to check if the
superblock has pquotino.

Keep backward compatibilty by alowing mount of older superblock
with no separate pquota inode.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

diff --git a/fs/xfs/xfs_sb.h b/fs/xfs/xfs_sb.h
index 78f9e70..a6ff9d6 100644
--- a/fs/xfs/xfs_sb.h
+++ b/fs/xfs/xfs_sb.h
@@ -618,16 +618,23 @@
 	return (sbp->sb_features_log_incompat & feature) != 0;
 }
 
-static inline bool
-xfs_is_quota_inode(struct xfs_sb *sbp, xfs_ino_t ino)
+static inline int xfs_sb_version_has_pquotino(xfs_sb_t *sbp)
 {
-	return (ino == sbp->sb_uquotino || ino == sbp->sb_gquotino);
+	return XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5;
 }
 
 /*
  * end of superblock version macros
  */
 
+static inline bool
+xfs_is_quota_inode(struct xfs_sb *sbp, xfs_ino_t ino)
+{
+	return (ino == sbp->sb_uquotino ||
+		ino == sbp->sb_gquotino ||
+		ino == sbp->sb_pquotino);
+}
+
 #define XFS_SB_DADDR		((xfs_daddr_t)0) /* daddr in filesystem/ag */
 #define	XFS_SB_BLOCK(mp)	XFS_HDR_BLOCK(mp, XFS_SB_DADDR)
 #define XFS_BUF_TO_SBP(bp)	((xfs_dsb_t *)((bp)->b_addr))