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_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)
  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         ops->free(&dir);
 110 out:
 111 #endif
 112         return ret;
 113 }
 114
 115 static int
 116 adfs_match(struct qstr *name, struct object_info *obj)
 117 {
 118         int i;
 119
 120         if (name->len != obj->name_len)
 121                 return 0;
 122
 123         for (i = 0; i < name->len; i++) {
 124                 char c1, c2;
 125
 126                 c1 = name->name[i];
 127                 c2 = obj->name[i];
 128
 129                 if (c1 >= 'A' && c1 <= 'Z')
 130                         c1 += 'a' - 'A';
 131                 if (c2 >= 'A' && c2 <= 'Z')
 132                         c2 += 'a' - 'A';
 133
 134                 if (c1 != c2)
 135                         return 0;
 136         }
 137         return 1;
 138 }
 139
 140 static int
 141 adfs_dir_lookup_byname(struct inode *inode, struct qstr *name, struct object_info *obj)
 142 {
 143         struct super_block *sb = inode->i_sb;
 144         struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir;
 145         struct adfs_dir dir;
 146         int ret;
 147
 148         ret = ops->read(sb, inode->i_ino, inode->i_size, &dir);
 149         if (ret)
 150                 goto out;
 151
 152         if (ADFS_I(inode)->parent_id != dir.parent_id) {
 153                 adfs_error(sb, "parent directory changed under me! (%lx but got %lx)\n",
 154                            ADFS_I(inode)->parent_id, dir.parent_id);
 155                 ret = -EIO;
 156                 goto free_out;
 157         }
 158
 159         obj->parent_id = inode->i_ino;
 160
 161         /*
 162          * '.' is handled by reserved_lookup() in fs/namei.c
 163          */
 164         if (name->len == 2 && name->name[0] == '.' && name->name[1] == '.') {
 165                 /*
 166                  * Currently unable to fill in the rest of 'obj',
 167                  * but this is better than nothing.  We need to
 168                  * ascend one level to find it's parent.
 169                  */
 170                 obj->name_len = 0;
 171                 obj->file_id  = obj->parent_id;
 172                 goto free_out;
 173         }
 174
 175         read_lock(&adfs_dir_lock);
 176
 177         ret = ops->setpos(&dir, 0);
 178         if (ret)
 179                 goto unlock_out;
 180
 181         ret = -ENOENT;
 182         while (ops->getnext(&dir, obj) == 0) {
 183                 if (adfs_match(name, obj)) {
 184                         ret = 0;
 185                         break;
 186                 }
 187         }
 188
 189 unlock_out:
 190         read_unlock(&adfs_dir_lock);
 191
 192 free_out:
 193         ops->free(&dir);
 194 out:
 195         return ret;
 196 }
 197
 198 const struct file_operations adfs_dir_operations = {
 199         .read           = generic_read_dir,
 200         .readdir        = adfs_readdir,
 201         .fsync          = file_fsync,
 202 };
 203
 204 static int
 205 adfs_hash(struct dentry *parent, struct qstr *qstr)
 206 {
 207         const unsigned int name_len = ADFS_SB(parent->d_sb)->s_namelen;
 208         const unsigned char *name;
 209         unsigned long hash;
 210         int i;
 211
 212         if (qstr->len < name_len)
 213                 return 0;
 214
 215         /*
 216          * Truncate the name in place, avoids
 217          * having to define a compare function.
 218          */
 219         qstr->len = i = name_len;
 220         name = qstr->name;
 221         hash = init_name_hash();
 222         while (i--) {
 223                 char c;
 224
 225                 c = *name++;
 226                 if (c >= 'A' && c <= 'Z')
 227                         c += 'a' - 'A';
 228
 229                 hash = partial_name_hash(c, hash);
 230         }
 231         qstr->hash = end_name_hash(hash);
 232
 233         return 0;
 234 }
 235
 236 /*
 237  * Compare two names, taking note of the name length
 238  * requirements of the underlying filesystem.
 239  */
 240 static int
 241 adfs_compare(struct dentry *parent, struct qstr *entry, struct qstr *name)
 242 {
 243         int i;
 244
 245         if (entry->len != name->len)
 246                 return 1;
 247
 248         for (i = 0; i < name->len; i++) {
 249                 char a, b;
 250
 251                 a = entry->name[i];
 252                 b = name->name[i];
 253
 254                 if (a >= 'A' && a <= 'Z')
 255                         a += 'a' - 'A';
 256                 if (b >= 'A' && b <= 'Z')
 257                         b += 'a' - 'A';
 258
 259                 if (a != b)
 260                         return 1;
 261         }
 262         return 0;
 263 }
 264
 265 struct dentry_operations adfs_dentry_operations = {
 266         .d_hash         = adfs_hash,
 267         .d_compare      = adfs_compare,
 268 };
 269
 270 static struct dentry *
 271 adfs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
 272 {
 273         struct inode *inode = NULL;
 274         struct object_info obj;
 275         int error;
 276
 277         dentry->d_op = &adfs_dentry_operations;
 278         lock_kernel();
 279         error = adfs_dir_lookup_byname(dir, &dentry->d_name, &obj);
 280         if (error == 0) {
 281                 error = -EACCES;
 282                 /*
 283                  * This only returns NULL if get_empty_inode
 284                  * fails.
 285                  */
 286                 inode = adfs_iget(dir->i_sb, &obj);
 287                 if (inode)
 288                         error = 0;
 289         }
 290         unlock_kernel();
 291         d_add(dentry, inode);
 292         return ERR_PTR(error);
 293 }
 294
 295 /*
 296  * directories can handle most operations...
 297  */
 298 struct inode_operations adfs_dir_inode_operations = {
 299         .lookup         = adfs_lookup,
 300         .setattr        = adfs_notify_change,
 301 };