fixed unmount

statsfs.c

@@ -1,4 +1,3 @@
-// libfs.c
 #include <linux/fs.h>
 #include <linux/init.h>
 #include <linux/module.h>
@@ -7,6 +6,9 @@
 #include <linux/namei.h>
 #include <linux/mount.h>
 #include <linux/dcache.h>
+#include <linux/list.h>
+#include <linux/fs_context.h>
+#include <linux/err.h>
 
 #define LIBFS_MAGIC 0xA0B0C0D0
 #define LIBFS_BOOKS_MODE 01777
@@ -14,9 +16,8 @@
 #define LIBFS_SUBDIR_MODE 01777
 
 static struct super_block *libfs_sb;
-
-// Track books inode to monitor link targets
 static struct inode *books_inode = NULL;
+static struct vfsmount *libfs_mnt;
 
 static const struct super_operations libfs_sops = {
         .statfs = simple_statfs,
@@ -39,7 +40,7 @@ static struct inode *libfs_get_inode(struct super_block *sb, umode_t mode) {
     if (S_ISDIR(mode)) {
         inode->i_fop = &simple_dir_operations;
     } else {
-        inode->i_fop = &libfs_file_ops; // fallback
+        inode->i_fop = &libfs_file_ops;
     }
     inode->i_mode = mode;
     return inode;
@@ -49,9 +50,51 @@ static bool is_protected_dentry(struct dentry *dentry) {
     return (strcmp(dentry->d_name.name, "books") == 0 || strcmp(dentry->d_name.name, "authors") == 0);
 }
 
+struct cleanup_ctx {
+    struct inode *victim;
+};
+
+static void libfs_cleanup_links(struct inode *victim)
+{
+    struct dentry *root = libfs_sb->s_root;
+
+    struct qstr authors_q = QSTR_INIT("authors", 7);
+    struct dentry *authors = d_lookup(root, &authors_q);
+    if (!authors || d_really_is_negative(authors)) {
+        dput(authors);
+        return;
+    }
+
+    // Здесь конкретный пример: если ты сам знаешь имя линка на victim
+    // То можешь через d_lookup() найти его и удалить
+    struct qstr filename = QSTR_INIT("some_symlink", 12);
+    struct dentry *maybe_link = d_lookup(authors, &filename);
+
+    if (maybe_link && maybe_link->d_inode == victim) {
+        inode_lock(authors->d_inode);
+        vfs_unlink(NULL, authors->d_inode, maybe_link, NULL);
+        inode_unlock(authors->d_inode);
+    }
+
+    dput(maybe_link);
+    dput(authors);
+}
+
+static int libfs_unlink(struct inode *dir, struct dentry *dentry) {
+    if (dir == libfs_sb->s_root->d_inode && is_protected_dentry(dentry))
+        return -EPERM;
+
+    struct inode *victim = dentry->d_inode;
+    int ret = simple_unlink(dir, dentry);
+    if (ret == 0 && dir == books_inode) {
+        libfs_cleanup_links(victim);
+    }
+    return ret;
+}
+
 static int libfs_mkdir(struct mnt_idmap *idmap, struct inode *dir, struct dentry *dentry, umode_t mode) {
     if (dir == libfs_sb->s_root->d_inode) {
-        return -EPERM; // no mkdir in root
+        return -EPERM;
     }
     struct inode *inode = libfs_get_inode(dir->i_sb, S_IFDIR | LIBFS_SUBDIR_MODE);
     if (!inode)
@@ -62,12 +105,6 @@ static int libfs_mkdir(struct mnt_idmap *idmap, struct inode *dir, struct dentry
     return 0;
 }
 
-static int libfs_unlink(struct inode *dir, struct dentry *dentry) {
-    if (dir == libfs_sb->s_root->d_inode && is_protected_dentry(dentry))
-        return -EPERM;
-    return simple_unlink(dir, dentry);
-}
-
 static int libfs_rmdir(struct inode *dir, struct dentry *dentry) {
     if (dir == libfs_sb->s_root->d_inode && is_protected_dentry(dentry))
         return -EPERM;
@@ -145,10 +182,15 @@ static struct file_system_type libfs_type = {
 };
 
 static int __init libfs_init(void) {
-    return register_filesystem(&libfs_type);
+    int ret = register_filesystem(&libfs_type);
+    if (ret)
+        return ret;
+    libfs_mnt = kern_mount(&libfs_type);
+    return PTR_ERR_OR_ZERO(libfs_mnt);
 }
 
 static void __exit libfs_exit(void) {
+    kern_unmount(libfs_mnt);
     unregister_filesystem(&libfs_type);
 }