fs/adfs/dir.c

   1 /*
   2  * linux/fs/adfs/dir.c
   3  *
   4  * Copyright (C) 1999-2000 Russell King
   5  *
   6  * Common directory handling for ADFS
   7  */
   8 #include <linux/config.h>
   9 #include <linux/version.h>
  10 #include <linux/errno.h>
  11 #include <linux/fs.h>
  12 #include <linux/adfs_fs.h>
  13 #include <linux/sched.h>
  14 #include <linux/stat.h>
  15 #include <linux/spinlock.h>
  16
  17 #include "adfs.h"
  18
  19 /*
  20  * For future.  This should probably be per-directory.
  21  */
  22 static rwlock_t adfs_dir_lock;
  23
  24 static int
  25 adfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
  26 {
  27         struct inode *inode = filp->f_dentry->d_inode;
  28         struct super_block *sb = inode->i_sb;
  29         struct adfs_dir_ops *ops = sb->u.adfs_sb.s_dir;
  30         struct object_info obj;
  31         struct adfs_dir dir;
  32         int ret = 0;
  33
  34         if (filp->f_pos >> 32)
  35                 goto out;
  36
  37         ret = ops->read(sb, inode->i_ino, inode->i_size, &dir);
  38         if (ret)
  39                 goto out;
  40
  41         switch ((unsigned long)filp->f_pos) {
  42         case 0:
  43                 if (filldir(dirent, ".", 1, 0, inode->i_ino) < 0)
  44                         goto free_out;
  45                 filp->f_pos += 1;
  46
  47         case 1:
  48                 if (filldir(dirent, "..", 2, 1, dir.parent_id) < 0)
  49                         goto free_out;
  50                 filp->f_pos += 1;
  51
  52         default:
  53                 break;
  54         }
  55
  56         read_lock(&adfs_dir_lock);
  57
  58         ret = ops->setpos(&dir, filp->f_pos - 2);
  59         if (ret)
  60                 goto unlock_out;
  61         while (ops->getnext(&dir, &obj) == 0) {
  62                 if (filldir(dirent, obj.name, obj.name_len,
  63                             filp->f_pos, obj.file_id) < 0)
  64                         goto unlock_out;
  65                 filp->f_pos += 1;
  66         }
  67
  68 unlock_out:
  69         read_unlock(&adfs_dir_lock);
  70
  71 free_out:
  72         ops->free(&dir);
  73
  74 out:
  75         return ret;
  76 }
  77
  78 int
  79 adfs_dir_update(struct super_block *sb, struct object_info *obj)
  80 {
  81         int ret = -EINVAL;
  82 #ifdef CONFIG_ADFS_FS_RW
  83         struct adfs_dir_ops *ops = sb->u.adfs_sb.s_dir;
  84         struct adfs_dir dir;
  85
  86         printk(KERN_INFO "adfs_dir_update: object %06X in dir %06X\n",
  87                  obj->file_id, obj->parent_id);
  88
  89         if (!ops->update) {
  90                 ret = -EINVAL;
  91                 goto out;
  92         }
  93
  94         ret = ops->read(sb, obj->parent_id, 0, &dir);
  95         if (ret)
  96                 goto out;
  97
  98         write_lock(&adfs_dir_lock);
  99         ret = ops->update(&dir, obj);
 100         write_unlock(&adfs_dir_lock);
 101
 102         ops->free(&dir);
 103 out:
 104 #endif
 105         return ret;
 106 }
 107
 108 static int
 109 adfs_match(struct qstr *name, struct object_info *obj)
 110 {
 111         int i;
 112
 113         if (name->len != obj->name_len)
 114                 return 0;
 115
 116         for (i = 0; i < name->len; i++) {
 117                 char c1, c2;
 118
 119                 c1 = name->name[i];
 120                 c2 = obj->name[i];
 121
 122                 if (c1 >= 'A' && c1 <= 'Z')
 123                         c1 += 'a' - 'A';
 124                 if (c2 >= 'A' && c2 <= 'Z')
 125                         c2 += 'a' - 'A';
 126
 127                 if (c1 != c2)
 128                         return 0;
 129         }
 130         return 1;
 131 }
 132
 133 static int
 134 adfs_dir_lookup_byname(struct inode *inode, struct qstr *name, struct object_info *obj)
 135 {
 136         struct super_block *sb = inode->i_sb;
 137         struct adfs_dir_ops *ops = sb->u.adfs_sb.s_dir;
 138         struct adfs_dir dir;
 139         int ret;
 140
 141         ret = ops->read(sb, inode->i_ino, inode->i_size, &dir);
 142         if (ret)
 143                 goto out;
 144
 145         if (inode->u.adfs_i.parent_id != dir.parent_id) {
 146                 adfs_error(sb, "parent directory changed under me! (%lx but got %lx)\n",
 147                            inode->u.adfs_i.parent_id, dir.parent_id);
 148                 ret = -EIO;
 149                 goto free_out;
 150         }
 151
 152         obj->parent_id = inode->i_ino;
 153
 154         /*
 155          * '.' is handled by reserved_lookup() in fs/namei.c
 156          */
 157         if (name->len == 2 && name->name[0] == '.' && name->name[1] == '.') {
 158                 /*
 159                  * Currently unable to fill in the rest of 'obj',
 160                  * but this is better than nothing.  We need to
 161                  * ascend one level to find it's parent.
 162                  */
 163                 obj->name_len = 0;
 164                 obj->file_id  = obj->parent_id;
 165                 goto free_out;
 166         }
 167
 168         read_lock(&adfs_dir_lock);
 169
 170         ret = ops->setpos(&dir, 0);
 171         if (ret)
 172                 goto unlock_out;
 173
 174         ret = -ENOENT;
 175         while (ops->getnext(&dir, obj) == 0) {
 176                 if (adfs_match(name, obj)) {
 177                         ret = 0;
 178                         break;
 179                 }
 180         }
 181
 182 unlock_out:
 183         read_unlock(&adfs_dir_lock);
 184
 185 free_out:
 186         ops->free(&dir);
 187 out:
 188         return ret;
 189 }
 190
 191 struct file_operations adfs_dir_operations = {
 192         read:           generic_read_dir,
 193         readdir:        adfs_readdir,
 194         fsync:          file_fsync,
 195 };
 196
 197 static int
 198 adfs_hash(struct dentry *parent, struct qstr *qstr)
 199 {
 200         const unsigned int name_len = parent->d_sb->u.adfs_sb.s_namelen;
 201         const unsigned char *name;
 202         unsigned long hash;
 203         int i;
 204
 205         if (qstr->len < name_len)
 206                 return 0;
 207
 208         /*
 209          * Truncate the name in place, avoids
 210          * having to define a compare function.
 211          */
 212         qstr->len = i = name_len;
 213         name = qstr->name;
 214         hash = init_name_hash();
 215         while (i--) {
 216                 char c;
 217
 218                 c = *name++;
 219                 if (c >= 'A' && c <= 'Z')
 220                         c += 'a' - 'A';
 221
 222                 hash = partial_name_hash(c, hash);
 223         }
 224         qstr->hash = end_name_hash(hash);
 225
 226         return 0;
 227 }
 228
 229 /*
 230  * Compare two names, taking note of the name length
 231  * requirements of the underlying filesystem.
 232  */
 233 static int
 234 adfs_compare(struct dentry *parent, struct qstr *entry, struct qstr *name)
 235 {
 236         int i;
 237
 238         if (entry->len != name->len)
 239                 return 1;
 240
 241         for (i = 0; i < name->len; i++) {
 242                 char a, b;
 243
 244                 a = entry->name[i];
 245                 b = name->name[i];
 246
 247                 if (a >= 'A' && a <= 'Z')
 248                         a += 'a' - 'A';
 249                 if (b >= 'A' && b <= 'Z')
 250                         b += 'a' - 'A';
 251
 252                 if (a != b)
 253                         return 1;
 254         }
 255         return 0;
 256 }
 257
 258 struct dentry_operations adfs_dentry_operations = {
 259         d_hash:         adfs_hash,
 260         d_compare:      adfs_compare,
 261 };
 262
 263 struct dentry *adfs_lookup(struct inode *dir, struct dentry *dentry)
 264 {
 265         struct inode *inode = NULL;
 266         struct object_info obj;
 267         int error;
 268
 269         dentry->d_op = &adfs_dentry_operations;
 270         error = adfs_dir_lookup_byname(dir, &dentry->d_name, &obj);
 271         if (error == 0) {
 272                 error = -EACCES;
 273                 /*
 274                  * This only returns NULL if get_empty_inode
 275                  * fails.
 276                  */
 277                 inode = adfs_iget(dir->i_sb, &obj);
 278                 if (inode)
 279                         error = 0;
 280         }
 281         d_add(dentry, inode);
 282         return ERR_PTR(error);
 283 }
 284
 285 /*
 286  * directories can handle most operations...
 287  */
 288 struct inode_operations adfs_dir_inode_operations = {
 289         lookup:         adfs_lookup,
 290         setattr:        adfs_notify_change,
 291 };