X-Git-Url: http://pileus.org/git/?a=blobdiff_plain;f=fs%2Fnamespace.c;h=a7bea8c8bd469e7760aa1dc098478eef5b1be518;hb=9801b321ecdb6708365b6825bf728c8e433fca00;hp=4740f7bdb556289c789daac2ad2dd9035d802e70;hpb=6fac98dd218653c6aff8a0f56305c424930cea2a;p=~andy%2Flinux

diff --git a/fs/namespace.c b/fs/namespace.c
index 4740f7bdb55..a7bea8c8bd4 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1060,11 +1060,8 @@ static int do_umount(struct vfsmount *mnt, int flags)
 		 * we just try to remount it readonly.
 		 */
 		down_write(&sb->s_umount);
-		if (!(sb->s_flags & MS_RDONLY)) {
-			lock_kernel();
+		if (!(sb->s_flags & MS_RDONLY))
 			retval = do_remount_sb(sb, MS_RDONLY, NULL, 0);
-			unlock_kernel();
-		}
 		up_write(&sb->s_umount);
 		return retval;
 	}
@@ -1630,7 +1627,9 @@ static int do_new_mount(struct path *path, char *type, int flags,
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
 
+	lock_kernel();
 	mnt = do_kern_mount(type, flags, name, data);
+	unlock_kernel();
 	if (IS_ERR(mnt))
 		return PTR_ERR(mnt);
 
@@ -1921,7 +1920,6 @@ long do_mount(char *dev_name, char *dir_name, char *type_page,
 	if (retval)
 		goto dput_out;
 
-	lock_kernel();
 	if (flags & MS_REMOUNT)
 		retval = do_remount(&path, flags & ~MS_REMOUNT, mnt_flags,
 				    data_page);
@@ -1934,12 +1932,26 @@ long do_mount(char *dev_name, char *dir_name, char *type_page,
 	else
 		retval = do_new_mount(&path, type_page, flags, mnt_flags,
 				      dev_name, data_page);
-	unlock_kernel();
 dput_out:
 	path_put(&path);
 	return retval;
 }
 
+static struct mnt_namespace *alloc_mnt_ns(void)
+{
+	struct mnt_namespace *new_ns;
+
+	new_ns = kmalloc(sizeof(struct mnt_namespace), GFP_KERNEL);
+	if (!new_ns)
+		return ERR_PTR(-ENOMEM);
+	atomic_set(&new_ns->count, 1);
+	new_ns->root = NULL;
+	INIT_LIST_HEAD(&new_ns->list);
+	init_waitqueue_head(&new_ns->poll);
+	new_ns->event = 0;
+	return new_ns;
+}
+
 /*
  * Allocate a new namespace structure and populate it with contents
  * copied from the namespace of the passed in task structure.
@@ -1951,14 +1963,9 @@ static struct mnt_namespace *dup_mnt_ns(struct mnt_namespace *mnt_ns,
 	struct vfsmount *rootmnt = NULL, *pwdmnt = NULL;
 	struct vfsmount *p, *q;
 
-	new_ns = kmalloc(sizeof(struct mnt_namespace), GFP_KERNEL);
-	if (!new_ns)
-		return ERR_PTR(-ENOMEM);
-
-	atomic_set(&new_ns->count, 1);
-	INIT_LIST_HEAD(&new_ns->list);
-	init_waitqueue_head(&new_ns->poll);
-	new_ns->event = 0;
+	new_ns = alloc_mnt_ns();
+	if (IS_ERR(new_ns))
+		return new_ns;
 
 	down_write(&namespace_sem);
 	/* First pass: copy the tree topology */
@@ -2022,6 +2029,24 @@ struct mnt_namespace *copy_mnt_ns(unsigned long flags, struct mnt_namespace *ns,
 	return new_ns;
 }
 
+/**
+ * create_mnt_ns - creates a private namespace and adds a root filesystem
+ * @mnt: pointer to the new root filesystem mountpoint
+ */
+struct mnt_namespace *create_mnt_ns(struct vfsmount *mnt)
+{
+	struct mnt_namespace *new_ns;
+
+	new_ns = alloc_mnt_ns();
+	if (!IS_ERR(new_ns)) {
+		mnt->mnt_ns = new_ns;
+		new_ns->root = mnt;
+		list_add(&new_ns->list, &new_ns->root->mnt_list);
+	}
+	return new_ns;
+}
+EXPORT_SYMBOL(create_mnt_ns);
+
 SYSCALL_DEFINE5(mount, char __user *, dev_name, char __user *, dir_name,
 		char __user *, type, unsigned long, flags, void __user *, data)
 {
@@ -2249,10 +2274,14 @@ void __init mnt_init(void)
 	init_mount_tree();
 }
 
-void __put_mnt_ns(struct mnt_namespace *ns)
+void put_mnt_ns(struct mnt_namespace *ns)
 {
-	struct vfsmount *root = ns->root;
+	struct vfsmount *root;
 	LIST_HEAD(umount_list);
+
+	if (!atomic_dec_and_lock(&ns->count, &vfsmount_lock))
+		return;
+	root = ns->root;
 	ns->root = NULL;
 	spin_unlock(&vfsmount_lock);
 	down_write(&namespace_sem);
@@ -2263,3 +2292,4 @@ void __put_mnt_ns(struct mnt_namespace *ns)
 	release_mounts(&umount_list);
 	kfree(ns);
 }
+EXPORT_SYMBOL(put_mnt_ns);