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