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