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