X-Git-Url: https://git.kernel.dk/?a=blobdiff_plain;f=fs%2Fnamespace.c;h=ba5237be1cf982e1953ffe829d79742a3e73c30e;hb=9393bd07cf218ca51d0e627653f906a9d76a9131;hp=41196209a9062d5ed62d520b1b77a910751e6fb9;hpb=413f81eba35d6ede9289b0c8a920c013a84fac71;p=linux-2.6-block.git

diff --git a/fs/namespace.c b/fs/namespace.c
index 41196209a906..ba5237be1cf9 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();
 	}
 
 	/*
@@ -1240,11 +1253,11 @@ Enomem:
 	return NULL;
 }
 
-struct vfsmount *collect_mounts(struct vfsmount *mnt, struct dentry *dentry)
+struct vfsmount *collect_mounts(struct path *path)
 {
 	struct vfsmount *tree;
 	down_write(&namespace_sem);
-	tree = copy_tree(mnt, dentry, CL_COPY_ALL | CL_PRIVATE);
+	tree = copy_tree(path->mnt, path->dentry, CL_COPY_ALL | CL_PRIVATE);
 	up_write(&namespace_sem);
 	return tree;
 }
@@ -1588,7 +1601,7 @@ static int do_move_mount(struct path *path, char *old_name)
 
 	down_write(&namespace_sem);
 	while (d_mountpoint(path->dentry) &&
-	       follow_down(&path->mnt, &path->dentry))
+	       follow_down(path))
 		;
 	err = -EINVAL;
 	if (!check_mnt(path->mnt) || !check_mnt(old_path.mnt))
@@ -1682,10 +1695,10 @@ int do_add_mount(struct vfsmount *newmnt, struct path *path,
 	down_write(&namespace_sem);
 	/* Something was mounted here while we slept */
 	while (d_mountpoint(path->dentry) &&
-	       follow_down(&path->mnt, &path->dentry))
+	       follow_down(path))
 		;
 	err = -EINVAL;
-	if (!check_mnt(path->mnt))
+	if (!(mnt_flags & MNT_SHRINKABLE) && !check_mnt(path->mnt))
 		goto unlock;
 
 	/* Refuse the same filesystem on the same mount point */