[XFS] Revisit the remount read only code again.

apparently the root file system are not being synced 
correctly during system shutdown

SGI Modid: 2.5.x-xfs:slinx:136269a

fs/xfs/linux/xfs_lrw.c

@@ -872,13 +872,12 @@ XFS_log_write_unmount_ro(bhv_desc_t	*bdp)
 	int error;
 
 	mp = XFS_BHVTOM(bdp);
-	xfs_binval(mp->m_ddev_targp);
+	pagebuf_delwri_flush(mp->m_ddev_targp, PBDF_WAIT, &pincount);
+	xfs_finish_reclaim_all(mp);
 
 	do {
-		xfs_log_force(mp, (xfs_lsn_t)0, XFS_LOG_FORCE | XFS_LOG_SYNC);
 		VFS_SYNC(XFS_MTOVFS(mp), SYNC_ATTR|SYNC_WAIT, NULL, error);
-		pagebuf_delwri_flush(mp->m_ddev_targp,
-				PBDF_WAIT, &pincount);
+		pagebuf_delwri_flush(mp->m_ddev_targp, PBDF_WAIT, &pincount);
 		if (pincount == 0) {delay(50); count++;}
 	}  while (count < 2);
 

fs/xfs/xfs_inode.h

@@ -481,6 +481,7 @@ void		xfs_iunlock_map_shared(xfs_inode_t *, uint);
 void		xfs_ifunlock(xfs_inode_t *);
 void		xfs_ireclaim(xfs_inode_t *);
 int		xfs_finish_reclaim(xfs_inode_t *, int, int);
+int		xfs_reclaim_all(struct xfs_mount *);
 
 /*
  * xfs_inode.c prototypes.

fs/xfs/xfs_vnodeops.c

@@ -82,7 +82,7 @@ xfs_open(
 /*
  * xfs_getattr
  */
-STATIC int
+int
 xfs_getattr(
 	bhv_desc_t	*bdp,
 	vattr_t		*vap,
@@ -4060,6 +4060,49 @@ xfs_finish_reclaim(
 	return 0;
 }
 
+int
+xfs_finish_reclaim_all(xfs_mount_t *mp)
+{
+	int		purged;
+	xfs_inode_t	*ip;
+	vnode_t		*vp;
+	int		done = 0;
+
+	while (!done) {
+		purged = 0;
+		XFS_MOUNT_ILOCK(mp);
+		ip = mp->m_inodes;
+		if (ip == NULL) {
+			break;
+		}
+		do {
+			/* Make sure we skip markers inserted by sync */
+			if (ip->i_mount == NULL) {
+				ip = ip->i_mnext;
+				continue;
+			}
+	
+			/*
+			 * It's up to our caller to purge the root
+			 * and quota vnodes later.
+			 */
+			vp = XFS_ITOV_NULL(ip);
+	
+			if (!vp) {
+				XFS_MOUNT_IUNLOCK(mp);	
+				xfs_finish_reclaim(ip, 0, XFS_IFLUSH_ASYNC);
+				purged = 1;
+				break;
+			}
+		} while (ip != mp->m_inodes);
+	
+		done = !purged;
+	}
+
+	XFS_MOUNT_IUNLOCK(mp);
+	return 0;
+}
+
 /*
  * xfs_alloc_file_space()
  *	This routine allocates disk space for the given file.