debugfs: implement symbolic links

debugfs: implement symbolic links

Implement a new function debugfs_create_symlink() which can be used
to create symbolic links in debugfs. This function can be useful
for people moving functionality from /proc to debugfs (e.g. the
gcov-kernel patch).

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 12 insertions, 0 deletions

diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index 8d130cc..682f928 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -16,6 +16,7 @@
 #include <linux/module.h>
 #include <linux/fs.h>
 #include <linux/pagemap.h>
+#include <linux/namei.h>
 #include <linux/debugfs.h>
 
 static ssize_t default_read_file(struct file *file, char __user *buf,
@@ -44,6 +45,17 @@ const struct file_operations debugfs_file_operations = {
 	.open =		default_open,
 };
 
+static void *debugfs_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+	nd_set_link(nd, dentry->d_inode->i_private);
+	return NULL;
+}
+
+const struct inode_operations debugfs_link_operations = {
+	.readlink       = generic_readlink,
+	.follow_link    = debugfs_follow_link,
+};
+
 static void debugfs_u8_set(void *data, u64 val)
 {
 	*(u8 *)data = val;