linux/fs/adfs/dir.c
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   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 */
  17static DEFINE_RWLOCK(adfs_dir_lock);
  18
  19static int
  20adfs_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
  63unlock_out:
  64        read_unlock(&adfs_dir_lock);
  65
  66free_out:
  67        ops->free(&dir);
  68
  69out:
  70        return ret;
  71}
  72
  73int
  74adfs_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);
 104out:
 105#endif
 106        return ret;
 107}
 108
 109static int
 110adfs_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
 134static int
 135adfs_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
 183unlock_out:
 184        read_unlock(&adfs_dir_lock);
 185
 186free_out:
 187        ops->free(&dir);
 188out:
 189        return ret;
 190}
 191
 192const 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
 199static int
 200adfs_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 */
 236static int
 237adfs_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
 263const struct dentry_operations adfs_dentry_operations = {
 264        .d_hash         = adfs_hash,
 265        .d_compare      = adfs_compare,
 266};
 267
 268static struct dentry *
 269adfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
 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 */
 293const struct inode_operations adfs_dir_inode_operations = {
 294        .lookup         = adfs_lookup,
 295        .setattr        = adfs_notify_change,
 296};
 297
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