1 files changed, 22 insertions, 8 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index c6f54e4c4290..134d494158d9 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -695,12 +695,16 @@ static inline void mangle(struct seq_file *m, const char *s)
  */
 int generic_show_options(struct seq_file *m, struct vfsmount *mnt)
 {
-        const char *options = mnt->mnt_sb->s_options;
+        const char *options;
+
+        rcu_read_lock();
+        options = rcu_dereference(mnt->mnt_sb->s_options);
 
         if (options != NULL && options[0]) {
                 seq_putc(m, ',');
                 mangle(m, options);
         }
+        rcu_read_unlock();
 
         return 0;
 }
@@ -721,11 +725,22 @@ EXPORT_SYMBOL(generic_show_options);
  */
 void save_mount_options(struct super_block *sb, char *options)
 {
-        kfree(sb->s_options);
-        sb->s_options = kstrdup(options, GFP_KERNEL);
+        BUG_ON(sb->s_options);
+        rcu_assign_pointer(sb->s_options, kstrdup(options, GFP_KERNEL));
 }
 EXPORT_SYMBOL(save_mount_options);
 
+void replace_mount_options(struct super_block *sb, char *options)
+{
+        char *old = sb->s_options;
+        rcu_assign_pointer(sb->s_options, options);
+        if (old) {
+                synchronize_rcu();
+                kfree(old);
+        }
+}
+EXPORT_SYMBOL(replace_mount_options);
+
 #ifdef CONFIG_PROC_FS
 /* iterator */
 static void *m_start(struct seq_file *m, loff_t *pos)
@@ -1073,9 +1088,7 @@ static int do_umount(struct vfsmount *mnt, int flags)
          */
 
         if (flags & MNT_FORCE && sb->s_op->umount_begin) {
-                lock_kernel();
                 sb->s_op->umount_begin(sb);
-                unlock_kernel();
         }
 
         /*
@@ -1377,7 +1390,7 @@ static int attach_recursive_mnt(struct vfsmount *source_mnt,
         if (parent_path) {
                 detach_mnt(source_mnt, parent_path);
                 attach_mnt(source_mnt, path);
-                touch_mnt_namespace(current->nsproxy->mnt_ns);
+                touch_mnt_namespace(parent_path->mnt->mnt_ns);
         } else {
                 mnt_set_mountpoint(dest_mnt, dest_dentry, source_mnt);
                 commit_tree(source_mnt);
@@ -1920,8 +1933,9 @@ long do_mount(char *dev_name, char *dir_name, char *type_page,
         if (data_page)
                 ((char *)data_page)[PAGE_SIZE - 1] = 0;
 
-        /* Default to relatime */
-        mnt_flags |= MNT_RELATIME;
+        /* Default to relatime unless overriden */
+        if (!(flags & MS_NOATIME))
+                mnt_flags |= MNT_RELATIME;
 
         /* Separate the per-mountpoint flags */
         if (flags & MS_NOSUID)