proc: Allow creating permanently empty directories that serve as mount points
Add a new function proc_create_mount_point that when used to creates a
directory that can not be added to.
Add a new function is_empty_pde to test if a function is a mount
point.
Update the code to use make_empty_dir_inode when reporting
a permanently empty directory to the vfs.
Update the code to not allow adding to permanently empty directories.
Update /proc/openprom and /proc/fs/nfsd to be permanently empty directories.
Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index c835b94..aa27810 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -191,6 +191,12 @@
}
extern void pde_put(struct proc_dir_entry *);
+static inline bool is_empty_pde(const struct proc_dir_entry *pde)
+{
+ return S_ISDIR(pde->mode) && !pde->proc_iops;
+}
+struct proc_dir_entry *proc_create_mount_point(const char *name);
+
/*
* inode.c
*/