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