fs/adfs/dir.c

   1 /*
   2  *  linux/fs/adfs/dir.c
   3  *
   4  *  Copyright (C) 1999-2000 Russell King
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  *  Common directory handling for ADFS
  11  */
  12 #include <linux/errno.h>
  13 #include <linux/fs.h>
  14 #include <linux/adfs_fs.h>
  15 #include <linux/time.h>
  16 #include <linux/stat.h>
  17 #include <linux/spinlock.h>
  18 #include <linux/smp_lock.h>
  19 #include <linux/buffer_head.h>          /* for file_fsync() */
  20
  21 #include "adfs.h"
  22
  23 /*
  24  * For future.  This should probably be per-directory.
  25  */
  26 static DEFINE_RWLOCK(adfs_dir_lock);
  27
  28 static int
  29 adfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
  30 {
  31         struct inode *inode = filp->f_path.dentry->d_inode;
  32         struct super_block *sb = inode->i_sb;
  33         struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir;
  34         struct object_info obj;
  35         struct adfs_dir dir;
  36         int ret = 0;
  37
  38         lock_kernel();
  39
  40         if (filp->f_pos >> 32)
  41                 goto out;
  42
  43         ret = ops->read(sb, inode->i_ino, inode->i_size, &dir);
  44         if (ret)
  45                 goto out;
  46
  47         switch ((unsigned long)filp->f_pos) {
  48         case 0:
  49                 if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
  50                         goto free_out;
  51                 filp->f_pos += 1;
  52
  53         case 1:
  54                 if (filldir(dirent, "..", 2, 1, dir.parent_id, DT_DIR) < 0)
  55                         goto free_out;
  56                 filp->f_pos += 1;
  57
  58         default:
  59                 break;
  60         }
  61
  62         read_lock(&adfs_dir_lock);
  63
  64         ret = ops->setpos(&dir, filp->f_pos - 2);
  65         if (ret)
  66                 goto unlock_out;
  67         while (ops->getnext(&dir, &obj) == 0) {
  68                 if (filldir(dirent, obj.name, obj.name_len,
  69                             filp->f_pos, obj.file_id, DT_UNKNOWN) < 0)
  70                         goto unlock_out;
  71                 filp->f_pos += 1;
  72         }
  73
  74 unlock_out:
  75         read_unlock(&adfs_dir_lock);
  76
  77 free_out:
  78         ops->free(&dir);
  79
  80 out:
  81         unlock_kernel();
  82         return ret;
  83 }
  84
  85 int
  86 adfs_dir_update(struct super_block *sb, struct object_info *obj, int wait)
  87 {
  88         int ret = -EINVAL;
  89 #ifdef CONFIG_ADFS_FS_RW
  90         struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir;
  91         struct adfs_dir dir;
  92
  93         printk(KERN_INFO "adfs_dir_update: object %06X in dir %06X\n",
  94                  obj->file_id, obj->parent_id);
  95
  96         if (!ops->update) {
  97                 ret = -EINVAL;
  98                 goto out;
  99         }
 100
 101         ret = ops->read(sb, obj->parent_id, 0, &dir);
 102         if (ret)
 103                 goto out;
 104
 105         write_lock(&adfs_dir_lock);
 106         ret = ops->update(&dir, obj);
 107         write_unlock(&adfs_dir_lock);
 108
 109         if (wait) {
 110                 int err = ops->sync(&dir);
 111                 if (!ret)
 112                         ret = err;
 113         }
 114
 115         ops->free(&dir);
 116 out:
 117 #endif
 118         return ret;
 119 }
 120
 121 static int
 122 adfs_match(struct qstr *name, struct object_info *obj)
 123 {
 124         int i;
 125
 126         if (name->len != obj->name_len)
 127                 return 0;
 128
 129         for (i = 0; i < name->len; i++) {
 130                 char c1, c2;
 131
 132                 c1 = name->name[i];
 133                 c2 = obj->name[i];
 134
 135                 if (c1 >= 'A' && c1 <= 'Z')
 136                         c1 += 'a' - 'A';
 137                 if (c2 >= 'A' && c2 <= 'Z')
 138                         c2 += 'a' - 'A';
 139
 140                 if (c1 != c2)
 141                         return 0;
 142         }
 143         return 1;
 144 }
 145
 146 static int
 147 adfs_dir_lookup_byname(struct inode *inode, struct qstr *name, struct object_info *obj)
 148 {
 149         struct super_block *sb = inode->i_sb;
 150         struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir;
 151         struct adfs_dir dir;
 152         int ret;
 153
 154         ret = ops->read(sb, inode->i_ino, inode->i_size, &dir);
 155         if (ret)
 156                 goto out;
 157
 158         if (ADFS_I(inode)->parent_id != dir.parent_id) {
 159                 adfs_error(sb, "parent directory changed under me! (%lx but got %lx)\n",
 160                            ADFS_I(inode)->parent_id, dir.parent_id);
 161                 ret = -EIO;
 162                 goto free_out;
 163         }
 164
 165         obj->parent_id = inode->i_ino;
 166
 167         /*
 168          * '.' is handled by reserved_lookup() in fs/namei.c
 169          */
 170         if (name->len == 2 && name->name[0] == '.' && name->name[1] == '.') {
 171                 /*
 172                  * Currently unable to fill in the rest of 'obj',
 173                  * but this is better than nothing.  We need to
 174                  * ascend one level to find it's parent.
 175                  */
 176                 obj->name_len = 0;
 177                 obj->file_id  = obj->parent_id;
 178                 goto free_out;
 179         }
 180
 181         read_lock(&adfs_dir_lock);
 182
 183         ret = ops->setpos(&dir, 0);
 184         if (ret)
 185                 goto unlock_out;
 186
 187         ret = -ENOENT;
 188         while (ops->getnext(&dir, obj) == 0) {
 189                 if (adfs_match(name, obj)) {
 190                         ret = 0;
 191                         break;
 192                 }
 193         }
 194
 195 unlock_out:
 196         read_unlock(&adfs_dir_lock);
 197
 198 free_out:
 199         ops->free(&dir);
 200 out:
 201         return ret;
 202 }
 203
 204 const struct file_operations adfs_dir_operations = {
 205         .read           = generic_read_dir,
 206         .llseek         = generic_file_llseek,
 207         .readdir        = adfs_readdir,
 208         .fsync          = simple_fsync,
 209 };
 210
 211 static int
 212 adfs_hash(struct dentry *parent, struct qstr *qstr)
 213 {
 214         const unsigned int name_len = ADFS_SB(parent->d_sb)->s_namelen;
 215         const unsigned char *name;
 216         unsigned long hash;
 217         int i;
 218
 219         if (qstr->len < name_len)
 220                 return 0;
 221
 222         /*
 223          * Truncate the name in place, avoids
 224          * having to define a compare function.
 225          */
 226         qstr->len = i = name_len;
 227         name = qstr->name;
 228         hash = init_name_hash();
 229         while (i--) {
 230                 char c;
 231
 232                 c = *name++;
 233                 if (c >= 'A' && c <= 'Z')
 234                         c += 'a' - 'A';
 235
 236                 hash = partial_name_hash(c, hash);
 237         }
 238         qstr->hash = end_name_hash(hash);
 239
 240         return 0;
 241 }
 242
 243 /*
 244  * Compare two names, taking note of the name length
 245  * requirements of the underlying filesystem.
 246  */
 247 static int
 248 adfs_compare(struct dentry *parent, struct qstr *entry, struct qstr *name)
 249 {
 250         int i;
 251
 252         if (entry->len != name->len)
 253                 return 1;
 254
 255         for (i = 0; i < name->len; i++) {
 256                 char a, b;
 257
 258                 a = entry->name[i];
 259                 b = name->name[i];
 260
 261                 if (a >= 'A' && a <= 'Z')
 262                         a += 'a' - 'A';
 263                 if (b >= 'A' && b <= 'Z')
 264                         b += 'a' - 'A';
 265
 266                 if (a != b)
 267                         return 1;
 268         }
 269         return 0;
 270 }
 271
 272 const struct dentry_operations adfs_dentry_operations = {
 273         .d_hash         = adfs_hash,
 274         .d_compare      = adfs_compare,
 275 };
 276
 277 static struct dentry *
 278 adfs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
 279 {
 280         struct inode *inode = NULL;
 281         struct object_info obj;
 282         int error;
 283
 284         dentry->d_op = &adfs_dentry_operations;
 285         lock_kernel();
 286         error = adfs_dir_lookup_byname(dir, &dentry->d_name, &obj);
 287         if (error == 0) {
 288                 error = -EACCES;
 289                 /*
 290                  * This only returns NULL if get_empty_inode
 291                  * fails.
 292                  */
 293                 inode = adfs_iget(dir->i_sb, &obj);
 294                 if (inode)
 295                         error = 0;
 296         }
 297         unlock_kernel();
 298         d_add(dentry, inode);
 299         return ERR_PTR(error);
 300 }
 301
 302 /*
 303  * directories can handle most operations...
 304  */
 305 const struct inode_operations adfs_dir_inode_operations = {
 306         .lookup         = adfs_lookup,
 307         .setattr        = adfs_notify_change,
 308 };