Commit c771d683 authored by Miklos Szeredi's avatar Miklos Szeredi
Browse files

vfs: introduce clone_private_mount() 



Overlayfs needs a private clone of the mount, so create a function for
this and export to modules.

Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
parent bd5d0856

fs/namespace.c

+27 −0
Original line number Diff line number Diff line
@@ -1686,6 +1686,33 @@ void drop_collected_mounts(struct vfsmount *mnt) 
	namespace_unlock();

}



/**

 * clone_private_mount - create a private clone of a path

 *

 * This creates a new vfsmount, which will be the clone of @path.  The new will

 * not be attached anywhere in the namespace and will be private (i.e. changes

 * to the originating mount won't be propagated into this).

 *

 * Release with mntput().

 */

struct vfsmount *clone_private_mount(struct path *path)

{

	struct mount *old_mnt = real_mount(path->mnt);

	struct mount *new_mnt;



	if (IS_MNT_UNBINDABLE(old_mnt))

		return ERR_PTR(-EINVAL);



	down_read(&namespace_sem);

	new_mnt = clone_mnt(old_mnt, path->dentry, CL_PRIVATE);

	up_read(&namespace_sem);

	if (IS_ERR(new_mnt))

		return ERR_CAST(new_mnt);



	return &new_mnt->mnt;

}

EXPORT_SYMBOL_GPL(clone_private_mount);



int iterate_mounts(int (*f)(struct vfsmount *, void *), void *arg,

		   struct vfsmount *root)

{

include/linux/mount.h

+3 −0
Original line number Diff line number Diff line
@@ -81,6 +81,9 @@ extern struct vfsmount *mntget(struct vfsmount *mnt); 
extern struct vfsmount *mnt_clone_internal(struct path *path);

extern int __mnt_is_readonly(struct vfsmount *mnt);



struct path;

extern struct vfsmount *clone_private_mount(struct path *path);



struct file_system_type;

extern struct vfsmount *vfs_kern_mount(struct file_system_type *type,

				      int flags, const char *name,