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