Isolate symlink function into a new file

Move the symlink function to a new source file to better align with the
Ext4 filesystem structure. This separation improves code organization
and maintainability.

Author: RoyWFHuang

Makefile

@@ -1,6 +1,5 @@
 obj-m += simplefs.o
-simplefs-objs := fs.o super.o inode.o file.o dir.o extent.o
-
+simplefs-objs := fs.o super.o inode.o file.o dir.o extent.o symlink.o
 KDIR ?= /lib/modules/$(shell uname -r)/build
 
 MKFS = mkfs.simplefs

inode.c

@@ -9,7 +9,6 @@
 #include "simplefs.h"
 
 static const struct inode_operations simplefs_inode_ops;
-static const struct inode_operations symlink_inode_ops;
 
 /* Either return the inode that corresponds to a given inode number (ino), if
  * it is already in the cache, or create a new inode object if it is not in the
@@ -1161,13 +1160,6 @@ static int simplefs_symlink(struct inode *dir,
     return ret;
 }
 
-static const char *simplefs_get_link(struct dentry *dentry,
-                                     struct inode *inode,
-                                     struct delayed_call *done)
-{
-    return inode->i_link;
-}
-
 static const struct inode_operations simplefs_inode_ops = {
     .lookup = simplefs_lookup,
     .create = simplefs_create,
@@ -1178,7 +1170,3 @@ static const struct inode_operations simplefs_inode_ops = {
     .link = simplefs_link,
     .symlink = simplefs_symlink,
 };
-
-static const struct inode_operations symlink_inode_ops = {
-    .get_link = simplefs_get_link,
-};

simplefs.h

@@ -159,4 +159,7 @@ struct simplefs_sb_info {
 #endif /* __KERNEL__ */
 };
 
+
+/* symlink.c */
+extern const struct inode_operations symlink_inode_ops;
 #endif /* SIMPLEFS_H */

symlink.c

@@ -0,0 +1,13 @@
+#include <linux/fs.h>
+#include "simplefs.h"
+
+static const char *simplefs_get_link(struct dentry *dentry,
+                                     struct inode *inode,
+                                     struct delayed_call *done)
+{
+    return inode->i_link;
+}
+
+const struct inode_operations symlink_inode_ops = {
+    .get_link = simplefs_get_link,
+};