fs/minix/namei.c

   1 /*
   2  *  linux/fs/minix/namei.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6
   7 #include "minix.h"
   8
   9 static int add_nondir(struct dentry *dentry, struct inode *inode)
  10 {
  11         int err = minix_add_link(dentry, inode);
  12         if (!err) {
  13                 d_instantiate(dentry, inode);
  14                 return 0;
  15         }
  16         inode_dec_link_count(inode);
  17         iput(inode);
  18         return err;
  19 }
  20
  21 static int minix_hash(struct dentry *dentry, struct qstr *qstr)
  22 {
  23         unsigned long hash;
  24         int i;
  25         const unsigned char *name;
  26
  27         i = minix_sb(dentry->d_inode->i_sb)->s_namelen;
  28         if (i >= qstr->len)
  29                 return 0;
  30         /* Truncate the name in place, avoids having to define a compare
  31            function. */
  32         qstr->len = i;
  33         name = qstr->name;
  34         hash = init_name_hash();
  35         while (i--)
  36                 hash = partial_name_hash(*name++, hash);
  37         qstr->hash = end_name_hash(hash);
  38         return 0;
  39 }
  40
  41 struct dentry_operations minix_dentry_operations = {
  42         .d_hash         = minix_hash,
  43 };
  44
  45 static struct dentry *minix_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd)
  46 {
  47         struct inode * inode = NULL;
  48         ino_t ino;
  49
  50         dentry->d_op = dir->i_sb->s_root->d_op;
  51
  52         if (dentry->d_name.len > minix_sb(dir->i_sb)->s_namelen)
  53                 return ERR_PTR(-ENAMETOOLONG);
  54
  55         ino = minix_inode_by_name(dentry);
  56         if (ino) {
  57                 inode = iget(dir->i_sb, ino);
  58
  59                 if (!inode)
  60                         return ERR_PTR(-EACCES);
  61         }
  62         d_add(dentry, inode);
  63         return NULL;
  64 }
  65
  66 static int minix_mknod(struct inode * dir, struct dentry *dentry, int mode, dev_t rdev)
  67 {
  68         int error;
  69         struct inode *inode;
  70
  71         if (!old_valid_dev(rdev))
  72                 return -EINVAL;
  73
  74         inode = minix_new_inode(dir, &error);
  75
  76         if (inode) {
  77                 inode->i_mode = mode;
  78                 minix_set_inode(inode, rdev);
  79                 mark_inode_dirty(inode);
  80                 error = add_nondir(dentry, inode);
  81         }
  82         return error;
  83 }
  84
  85 static int minix_create(struct inode * dir, struct dentry *dentry, int mode,
  86                 struct nameidata *nd)
  87 {
  88         return minix_mknod(dir, dentry, mode, 0);
  89 }
  90
  91 static int minix_symlink(struct inode * dir, struct dentry *dentry,
  92           const char * symname)
  93 {
  94         int err = -ENAMETOOLONG;
  95         int i = strlen(symname)+1;
  96         struct inode * inode;
  97
  98         if (i > dir->i_sb->s_blocksize)
  99                 goto out;
 100
 101         inode = minix_new_inode(dir, &err);
 102         if (!inode)
 103                 goto out;
 104
 105         inode->i_mode = S_IFLNK | 0777;
 106         minix_set_inode(inode, 0);
 107         err = page_symlink(inode, symname, i);
 108         if (err)
 109                 goto out_fail;
 110
 111         err = add_nondir(dentry, inode);
 112 out:
 113         return err;
 114
 115 out_fail:
 116         inode_dec_link_count(inode);
 117         iput(inode);
 118         goto out;
 119 }
 120
 121 static int minix_link(struct dentry * old_dentry, struct inode * dir,
 122         struct dentry *dentry)
 123 {
 124         struct inode *inode = old_dentry->d_inode;
 125
 126         if (inode->i_nlink >= minix_sb(inode->i_sb)->s_link_max)
 127                 return -EMLINK;
 128
 129         inode->i_ctime = CURRENT_TIME_SEC;
 130         inode_inc_link_count(inode);
 131         atomic_inc(&inode->i_count);
 132         return add_nondir(dentry, inode);
 133 }
 134
 135 static int minix_mkdir(struct inode * dir, struct dentry *dentry, int mode)
 136 {
 137         struct inode * inode;
 138         int err = -EMLINK;
 139
 140         if (dir->i_nlink >= minix_sb(dir->i_sb)->s_link_max)
 141                 goto out;
 142
 143         inode_inc_link_count(dir);
 144
 145         inode = minix_new_inode(dir, &err);
 146         if (!inode)
 147                 goto out_dir;
 148
 149         inode->i_mode = S_IFDIR | mode;
 150         if (dir->i_mode & S_ISGID)
 151                 inode->i_mode |= S_ISGID;
 152         minix_set_inode(inode, 0);
 153
 154         inode_inc_link_count(inode);
 155
 156         err = minix_make_empty(inode, dir);
 157         if (err)
 158                 goto out_fail;
 159
 160         err = minix_add_link(dentry, inode);
 161         if (err)
 162                 goto out_fail;
 163
 164         d_instantiate(dentry, inode);
 165 out:
 166         return err;
 167
 168 out_fail:
 169         inode_dec_link_count(inode);
 170         inode_dec_link_count(inode);
 171         iput(inode);
 172 out_dir:
 173         inode_dec_link_count(dir);
 174         goto out;
 175 }
 176
 177 static int minix_unlink(struct inode * dir, struct dentry *dentry)
 178 {
 179         int err = -ENOENT;
 180         struct inode * inode = dentry->d_inode;
 181         struct page * page;
 182         struct minix_dir_entry * de;
 183
 184         de = minix_find_entry(dentry, &page);
 185         if (!de)
 186                 goto end_unlink;
 187
 188         err = minix_delete_entry(de, page);
 189         if (err)
 190                 goto end_unlink;
 191
 192         inode->i_ctime = dir->i_ctime;
 193         inode_dec_link_count(inode);
 194 end_unlink:
 195         return err;
 196 }
 197
 198 static int minix_rmdir(struct inode * dir, struct dentry *dentry)
 199 {
 200         struct inode * inode = dentry->d_inode;
 201         int err = -ENOTEMPTY;
 202
 203         if (minix_empty_dir(inode)) {
 204                 err = minix_unlink(dir, dentry);
 205                 if (!err) {
 206                         inode_dec_link_count(dir);
 207                         inode_dec_link_count(inode);
 208                 }
 209         }
 210         return err;
 211 }
 212
 213 static int minix_rename(struct inode * old_dir, struct dentry *old_dentry,
 214                            struct inode * new_dir, struct dentry *new_dentry)
 215 {
 216         struct minix_sb_info * info = minix_sb(old_dir->i_sb);
 217         struct inode * old_inode = old_dentry->d_inode;
 218         struct inode * new_inode = new_dentry->d_inode;
 219         struct page * dir_page = NULL;
 220         struct minix_dir_entry * dir_de = NULL;
 221         struct page * old_page;
 222         struct minix_dir_entry * old_de;
 223         int err = -ENOENT;
 224
 225         old_de = minix_find_entry(old_dentry, &old_page);
 226         if (!old_de)
 227                 goto out;
 228
 229         if (S_ISDIR(old_inode->i_mode)) {
 230                 err = -EIO;
 231                 dir_de = minix_dotdot(old_inode, &dir_page);
 232                 if (!dir_de)
 233                         goto out_old;
 234         }
 235
 236         if (new_inode) {
 237                 struct page * new_page;
 238                 struct minix_dir_entry * new_de;
 239
 240                 err = -ENOTEMPTY;
 241                 if (dir_de && !minix_empty_dir(new_inode))
 242                         goto out_dir;
 243
 244                 err = -ENOENT;
 245                 new_de = minix_find_entry(new_dentry, &new_page);
 246                 if (!new_de)
 247                         goto out_dir;
 248                 inode_inc_link_count(old_inode);
 249                 minix_set_link(new_de, new_page, old_inode);
 250                 new_inode->i_ctime = CURRENT_TIME_SEC;
 251                 if (dir_de)
 252                         new_inode->i_nlink--;
 253                 inode_dec_link_count(new_inode);
 254         } else {
 255                 if (dir_de) {
 256                         err = -EMLINK;
 257                         if (new_dir->i_nlink >= info->s_link_max)
 258                                 goto out_dir;
 259                 }
 260                 inode_inc_link_count(old_inode);
 261                 err = minix_add_link(new_dentry, old_inode);
 262                 if (err) {
 263                         inode_dec_link_count(old_inode);
 264                         goto out_dir;
 265                 }
 266                 if (dir_de)
 267                         inode_inc_link_count(new_dir);
 268         }
 269
 270         minix_delete_entry(old_de, old_page);
 271         inode_dec_link_count(old_inode);
 272
 273         if (dir_de) {
 274                 minix_set_link(dir_de, dir_page, new_dir);
 275                 inode_dec_link_count(old_dir);
 276         }
 277         return 0;
 278
 279 out_dir:
 280         if (dir_de) {
 281                 kunmap(dir_page);
 282                 page_cache_release(dir_page);
 283         }
 284 out_old:
 285         kunmap(old_page);
 286         page_cache_release(old_page);
 287 out:
 288         return err;
 289 }
 290
 291 /*
 292  * directories can handle most operations...
 293  */
 294 struct inode_operations minix_dir_inode_operations = {
 295         .create         = minix_create,
 296         .lookup         = minix_lookup,
 297         .link           = minix_link,
 298         .unlink         = minix_unlink,
 299         .symlink        = minix_symlink,
 300         .mkdir          = minix_mkdir,
 301         .rmdir          = minix_rmdir,
 302         .mknod          = minix_mknod,
 303         .rename         = minix_rename,
 304         .getattr        = minix_getattr,
 305 };