init: add an init_umount helper

Like ksys_umount, but takes a kernel pointer for the destination path.
Switch over the umount in the init code, which just happen to work due to
the implicit set_fs(KERNEL_DS) during early init right now.

Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/fs/init.c b/fs/init.c
index c6eb724..9c8e31f 100644 (file)
--- a/fs/init.c
+++ b/fs/init.c
@@ -23,3 +23,17 @@ int __init init_mount(const char *dev_name, const char *dir_name,
        path_put(&path);
        return ret;
 }
+
+int __init init_umount(const char *name, int flags)
+{
+       int lookup_flags = LOOKUP_MOUNTPOINT;
+       struct path path;
+       int ret;
+
+       if (!(flags & UMOUNT_NOFOLLOW))
+               lookup_flags |= LOOKUP_FOLLOW;
+       ret = kern_path(name, lookup_flags, &path);
+       if (ret)
+               return ret;
+       return path_umount(&path, flags);
+}

diff --git a/fs/internal.h b/fs/internal.h
index 72ea0b6..491d1e6 100644 (file)
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -92,6 +92,7 @@ extern void dissolve_on_fput(struct vfsmount *);
 
 int path_mount(const char *dev_name, struct path *path,
                const char *type_page, unsigned long flags, void *data_page);
+int path_umount(struct path *path, int flags);
 
 /*
  * fs_struct.c

diff --git a/fs/namespace.c b/fs/namespace.c
index 2c4d759..a730179 100644 (file)
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1706,7 +1706,7 @@ static inline bool may_mandlock(void)
 }
 #endif
 
-static int path_umount(struct path *path, int flags)
+int path_umount(struct path *path, int flags)
 {
        struct mount *mnt;
        int retval;
@@ -1736,7 +1736,7 @@ dput_and_out:
        return retval;
 }
 
-int ksys_umount(char __user *name, int flags)
+static int ksys_umount(char __user *name, int flags)
 {
        int lookup_flags = LOOKUP_MOUNTPOINT;
        struct path path;

diff --git a/include/linux/init_syscalls.h b/include/linux/init_syscalls.h
index af9ea88..a5a2e7f 100644 (file)
--- a/include/linux/init_syscalls.h
+++ b/include/linux/init_syscalls.h
@@ -2,3 +2,4 @@
 
 int __init init_mount(const char *dev_name, const char *dir_name,
                const char *type_page, unsigned long flags, void *data_page);
+int __init init_umount(const char *name, int flags);

diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index e438161..1a4f5d8 100644 (file)
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -1236,7 +1236,6 @@ asmlinkage long sys_ni_syscall(void);
  * the ksys_xyzyyz() functions prototyped below.
  */
 
-int ksys_umount(char __user *name, int flags);
 int ksys_chroot(const char __user *filename);
 ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count);
 int ksys_chdir(const char __user *filename);

diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index 1f93362..6b020a0 100644 (file)
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -122,7 +122,7 @@ static void __init handle_initrd(void)
                else
                        printk("failed\n");
                printk(KERN_NOTICE "Unmounting old root\n");
-               ksys_umount("/old", MNT_DETACH);
+               init_umount("/old", MNT_DETACH);
        }
 }