Linux Cross Reference
Linux/fs/adfs/dir.c

   /*
    *  linux/fs/adfs/dir.c
    *
    *  Copyright (C) 1999-2000 Russell King
    *
    * This program is free software; you can redistribute it and/or modify
    * it under the terms of the GNU General Public License version 2 as
    * published by the Free Software Foundation.
    *
   *  Common directory handling for ADFS
   */
  #include <linux/config.h>
  #include <linux/version.h>
  #include <linux/errno.h>
  #include <linux/fs.h>
  #include <linux/adfs_fs.h>
  #include <linux/sched.h>
  #include <linux/stat.h>
  #include <linux/spinlock.h>
  
  #include "adfs.h"
  
  /*
   * For future.  This should probably be per-directory.
   */
  static rwlock_t adfs_dir_lock;
  
  static int
  adfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
  {
          struct inode *inode = filp->f_dentry->d_inode;
          struct super_block *sb = inode->i_sb;
          struct adfs_dir_ops *ops = sb->u.adfs_sb.s_dir;
          struct object_info obj;
          struct adfs_dir dir;
          int ret = 0;
  
          if (filp->f_pos >> 32)
                  goto out;
  
          ret = ops->read(sb, inode->i_ino, inode->i_size, &dir);
          if (ret)
                  goto out;
  
          switch ((unsigned long)filp->f_pos) {
          case 0:
                  if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
                          goto free_out;
                  filp->f_pos += 1;
  
          case 1:
                  if (filldir(dirent, "..", 2, 1, dir.parent_id, DT_DIR) < 0)
                          goto free_out;
                  filp->f_pos += 1;
  
          default:
                  break;
          }
  
          read_lock(&adfs_dir_lock);
  
          ret = ops->setpos(&dir, filp->f_pos - 2);
          if (ret)
                  goto unlock_out;
          while (ops->getnext(&dir, &obj) == 0) {
                  if (filldir(dirent, obj.name, obj.name_len,
                              filp->f_pos, obj.file_id, DT_UNKNOWN) < 0)
                          goto unlock_out;
                  filp->f_pos += 1;
          }
  
  unlock_out:
          read_unlock(&adfs_dir_lock);
  
  free_out:
          ops->free(&dir);
  
  out:
          return ret;
  }
  
  int
  adfs_dir_update(struct super_block *sb, struct object_info *obj)
  {
          int ret = -EINVAL;
  #ifdef CONFIG_ADFS_FS_RW
          struct adfs_dir_ops *ops = sb->u.adfs_sb.s_dir;
          struct adfs_dir dir;
  
          printk(KERN_INFO "adfs_dir_update: object %06X in dir %06X\n",
                   obj->file_id, obj->parent_id);
  
          if (!ops->update) {
                  ret = -EINVAL;
                  goto out;
          }
  
          ret = ops->read(sb, obj->parent_id, 0, &dir);
          if (ret)
                 goto out;
 
         write_lock(&adfs_dir_lock);
         ret = ops->update(&dir, obj);
         write_unlock(&adfs_dir_lock);
 
         ops->free(&dir);
 out:
 #endif
         return ret;
 }
 
 static int
 adfs_match(struct qstr *name, struct object_info *obj)
 {
         int i;
 
         if (name->len != obj->name_len)
                 return 0;
 
         for (i = 0; i < name->len; i++) {
                 char c1, c2;
 
                 c1 = name->name[i];
                 c2 = obj->name[i];
 
                 if (c1 >= 'A' && c1 <= 'Z')
                         c1 += 'a' - 'A';
                 if (c2 >= 'A' && c2 <= 'Z')
                         c2 += 'a' - 'A';
 
                 if (c1 != c2)
                         return 0;
         }
         return 1;
 }
 
 static int
 adfs_dir_lookup_byname(struct inode *inode, struct qstr *name, struct object_info *obj)
 {
         struct super_block *sb = inode->i_sb;
         struct adfs_dir_ops *ops = sb->u.adfs_sb.s_dir;
         struct adfs_dir dir;
         int ret;
 
         ret = ops->read(sb, inode->i_ino, inode->i_size, &dir);
         if (ret)
                 goto out;
 
         if (inode->u.adfs_i.parent_id != dir.parent_id) {
                 adfs_error(sb, "parent directory changed under me! (%lx but got %lx)\n",
                            inode->u.adfs_i.parent_id, dir.parent_id);
                 ret = -EIO;
                 goto free_out;
         }
 
         obj->parent_id = inode->i_ino;
 
         /*
          * '.' is handled by reserved_lookup() in fs/namei.c
          */
         if (name->len == 2 && name->name[0] == '.' && name->name[1] == '.') {
                 /*
                  * Currently unable to fill in the rest of 'obj',
                  * but this is better than nothing.  We need to
                  * ascend one level to find it's parent.
                  */
                 obj->name_len = 0;
                 obj->file_id  = obj->parent_id;
                 goto free_out;
         }
 
         read_lock(&adfs_dir_lock);
 
         ret = ops->setpos(&dir, 0);
         if (ret)
                 goto unlock_out;
 
         ret = -ENOENT;
         while (ops->getnext(&dir, obj) == 0) {
                 if (adfs_match(name, obj)) {
                         ret = 0;
                         break;
                 }
         }
 
 unlock_out:
         read_unlock(&adfs_dir_lock);
 
 free_out:
         ops->free(&dir);
 out:
         return ret;
 }
 
 struct file_operations adfs_dir_operations = {
         read:           generic_read_dir,
         readdir:        adfs_readdir,
         fsync:          file_fsync,
 };
 
 static int
 adfs_hash(struct dentry *parent, struct qstr *qstr)
 {
         const unsigned int name_len = parent->d_sb->u.adfs_sb.s_namelen;
         const unsigned char *name;
         unsigned long hash;
         int i;
 
         if (qstr->len < name_len)
                 return 0;
 
         /*
          * Truncate the name in place, avoids
          * having to define a compare function.
          */
         qstr->len = i = name_len;
         name = qstr->name;
         hash = init_name_hash();
         while (i--) {
                 char c;
 
                 c = *name++;
                 if (c >= 'A' && c <= 'Z')
                         c += 'a' - 'A';
 
                 hash = partial_name_hash(c, hash);
         }
         qstr->hash = end_name_hash(hash);
 
         return 0;
 }
 
 /*
  * Compare two names, taking note of the name length
  * requirements of the underlying filesystem.
  */
 static int
 adfs_compare(struct dentry *parent, struct qstr *entry, struct qstr *name)
 {
         int i;
 
         if (entry->len != name->len)
                 return 1;
 
         for (i = 0; i < name->len; i++) {
                 char a, b;
 
                 a = entry->name[i];
                 b = name->name[i];
 
                 if (a >= 'A' && a <= 'Z')
                         a += 'a' - 'A';
                 if (b >= 'A' && b <= 'Z')
                         b += 'a' - 'A';
 
                 if (a != b)
                         return 1;
         }
         return 0;
 }
 
 struct dentry_operations adfs_dentry_operations = {
         d_hash:         adfs_hash,
         d_compare:      adfs_compare,
 };
 
 struct dentry *adfs_lookup(struct inode *dir, struct dentry *dentry)
 {
         struct inode *inode = NULL;
         struct object_info obj;
         int error;
 
         dentry->d_op = &adfs_dentry_operations; 
         error = adfs_dir_lookup_byname(dir, &dentry->d_name, &obj);
         if (error == 0) {
                 error = -EACCES;
                 /*
                  * This only returns NULL if get_empty_inode
                  * fails.
                  */
                 inode = adfs_iget(dir->i_sb, &obj);
                 if (inode)
                         error = 0;
         }
         d_add(dentry, inode);
         return ERR_PTR(error);
 }
 
 /*
  * directories can handle most operations...
  */
 struct inode_operations adfs_dir_inode_operations = {
         lookup:         adfs_lookup,
         setattr:        adfs_notify_change,
 };