1 files changed, 33 insertions, 11 deletions

diff --git a/fs/gfs2/ops_super.c b/fs/gfs2/ops_super.c
index 320323d03479..458019569dcb 100644
--- a/fs/gfs2/ops_super.c
+++ b/fs/gfs2/ops_super.c
@@ -19,7 +19,6 @@
 #include <linux/delay.h>
 #include <linux/gfs2_ondisk.h>
 #include <linux/crc32.h>
-#include <linux/lm_interface.h>
 #include <linux/time.h>
 
 #include "gfs2.h"
@@ -27,7 +26,6 @@
 #include "glock.h"
 #include "inode.h"
 #include "log.h"
-#include "mount.h"
 #include "quota.h"
 #include "recovery.h"
 #include "rgrp.h"
@@ -40,6 +38,8 @@
 #include "bmap.h"
 #include "meta_io.h"
 
+#define args_neq(a1, a2, x) ((a1)->ar_##x != (a2)->ar_##x)
+
 /**
  * gfs2_write_inode - Make sure the inode is stable on the disk
  * @inode: The inode
@@ -435,25 +435,45 @@ static int gfs2_statfs(struct dentry *dentry, struct kstatfs *buf)
 static int gfs2_remount_fs(struct super_block *sb, int *flags, char *data)
 {
         struct gfs2_sbd *sdp = sb->s_fs_info;
+        struct gfs2_args args = sdp->sd_args; /* Default to current settings */
         int error;
 
-        error = gfs2_mount_args(sdp, data, 1);
+        error = gfs2_mount_args(sdp, &args, data);
         if (error)
                 return error;
 
+        /* Not allowed to change locking details */
+        if (strcmp(args.ar_lockproto, sdp->sd_args.ar_lockproto) ||
+            strcmp(args.ar_locktable, sdp->sd_args.ar_locktable) ||
+            strcmp(args.ar_hostdata, sdp->sd_args.ar_hostdata))
+                return -EINVAL;
+
+        /* Some flags must not be changed */
+        if (args_neq(&args, &sdp->sd_args, spectator) ||
+            args_neq(&args, &sdp->sd_args, ignore_local_fs) ||
+            args_neq(&args, &sdp->sd_args, localflocks) ||
+            args_neq(&args, &sdp->sd_args, localcaching) ||
+            args_neq(&args, &sdp->sd_args, meta))
+                return -EINVAL;
+
         if (sdp->sd_args.ar_spectator)
                 *flags |= MS_RDONLY;
-        else {
-                if (*flags & MS_RDONLY) {
-                        if (!(sb->s_flags & MS_RDONLY))
-                                error = gfs2_make_fs_ro(sdp);
-                } else if (!(*flags & MS_RDONLY) &&
-                           (sb->s_flags & MS_RDONLY)) {
+
+        if ((sb->s_flags ^ *flags) & MS_RDONLY) {
+                if (*flags & MS_RDONLY)
+                        error = gfs2_make_fs_ro(sdp);
+                else
                         error = gfs2_make_fs_rw(sdp);
-                }
+                if (error)
+                        return error;
         }
 
-        return error;
+        sdp->sd_args = args;
+        if (sdp->sd_args.ar_posix_acl)
+                sb->s_flags |= MS_POSIXACL;
+        else
+                sb->s_flags &= ~MS_POSIXACL;
+        return 0;
 }
 
 /**
@@ -588,6 +608,8 @@ static int gfs2_show_options(struct seq_file *s, struct vfsmount *mnt)
                 }
                 seq_printf(s, ",data=%s", state);
         }
+        if (args->ar_discard)
+                seq_printf(s, ",discard");
 
         return 0;
 }