fs/exofs/namei.c

   1 /*
   2  * Copyright (C) 2005, 2006
   3  * Avishay Traeger (avishay@gmail.com)
   4  * Copyright (C) 2008, 2009
   5  * Boaz Harrosh <ooo@electrozaur.com>
   6  *
   7  * Copyrights for code taken from ext2:
   8  *     Copyright (C) 1992, 1993, 1994, 1995
   9  *     Remy Card (card@masi.ibp.fr)
  10  *     Laboratoire MASI - Institut Blaise Pascal
  11  *     Universite Pierre et Marie Curie (Paris VI)
  12  *     from
  13  *     linux/fs/minix/inode.c
  14  *     Copyright (C) 1991, 1992  Linus Torvalds
  15  *
  16  * This file is part of exofs.
  17  *
  18  * exofs is free software; you can redistribute it and/or modify
  19  * it under the terms of the GNU General Public License as published by
  20  * the Free Software Foundation.  Since it is based on ext2, and the only
  21  * valid version of GPL for the Linux kernel is version 2, the only valid
  22  * version of GPL for exofs is version 2.
  23  *
  24  * exofs is distributed in the hope that it will be useful,
  25  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  26  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  27  * GNU General Public License for more details.
  28  *
  29  * You should have received a copy of the GNU General Public License
  30  * along with exofs; if not, write to the Free Software
  31  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  32  */
  33
  34 #include "exofs.h"
  35
  36 static inline int exofs_add_nondir(struct dentry *dentry, struct inode *inode)
  37 {
  38         int err = exofs_add_link(dentry, inode);
  39         if (!err) {
  40                 d_instantiate(dentry, inode);
  41                 return 0;
  42         }
  43         inode_dec_link_count(inode);
  44         iput(inode);
  45         return err;
  46 }
  47
  48 static struct dentry *exofs_lookup(struct inode *dir, struct dentry *dentry,
  49                                    unsigned int flags)
  50 {
  51         struct inode *inode;
  52         ino_t ino;
  53
  54         if (dentry->d_name.len > EXOFS_NAME_LEN)
  55                 return ERR_PTR(-ENAMETOOLONG);
  56
  57         ino = exofs_inode_by_name(dir, dentry);
  58         inode = ino ? exofs_iget(dir->i_sb, ino) : NULL;
  59         return d_splice_alias(inode, dentry);
  60 }
  61
  62 static int exofs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
  63                          bool excl)
  64 {
  65         struct inode *inode = exofs_new_inode(dir, mode);
  66         int err = PTR_ERR(inode);
  67         if (!IS_ERR(inode)) {
  68                 inode->i_op = &exofs_file_inode_operations;
  69                 inode->i_fop = &exofs_file_operations;
  70                 inode->i_mapping->a_ops = &exofs_aops;
  71                 mark_inode_dirty(inode);
  72                 err = exofs_add_nondir(dentry, inode);
  73         }
  74         return err;
  75 }
  76
  77 static int exofs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
  78                        dev_t rdev)
  79 {
  80         struct inode *inode;
  81         int err;
  82
  83         inode = exofs_new_inode(dir, mode);
  84         err = PTR_ERR(inode);
  85         if (!IS_ERR(inode)) {
  86                 init_special_inode(inode, inode->i_mode, rdev);
  87                 mark_inode_dirty(inode);
  88                 err = exofs_add_nondir(dentry, inode);
  89         }
  90         return err;
  91 }
  92
  93 static int exofs_symlink(struct inode *dir, struct dentry *dentry,
  94                           const char *symname)
  95 {
  96         struct super_block *sb = dir->i_sb;
  97         int err = -ENAMETOOLONG;
  98         unsigned l = strlen(symname)+1;
  99         struct inode *inode;
 100         struct exofs_i_info *oi;
 101
 102         if (l > sb->s_blocksize)
 103                 goto out;
 104
 105         inode = exofs_new_inode(dir, S_IFLNK | S_IRWXUGO);
 106         err = PTR_ERR(inode);
 107         if (IS_ERR(inode))
 108                 goto out;
 109
 110         oi = exofs_i(inode);
 111         if (l > sizeof(oi->i_data)) {
 112                 /* slow symlink */
 113                 inode->i_op = &page_symlink_inode_operations;
 114                 inode->i_mapping->a_ops = &exofs_aops;
 115                 memset(oi->i_data, 0, sizeof(oi->i_data));
 116
 117                 err = page_symlink(inode, symname, l);
 118                 if (err)
 119                         goto out_fail;
 120         } else {
 121                 /* fast symlink */
 122                 inode->i_op = &simple_symlink_inode_operations;
 123                 inode->i_link = (char *)oi->i_data;
 124                 memcpy(oi->i_data, symname, l);
 125                 inode->i_size = l-1;
 126         }
 127         mark_inode_dirty(inode);
 128
 129         err = exofs_add_nondir(dentry, inode);
 130 out:
 131         return err;
 132
 133 out_fail:
 134         inode_dec_link_count(inode);
 135         iput(inode);
 136         goto out;
 137 }
 138
 139 static int exofs_link(struct dentry *old_dentry, struct inode *dir,
 140                 struct dentry *dentry)
 141 {
 142         struct inode *inode = d_inode(old_dentry);
 143
 144         inode->i_ctime = CURRENT_TIME;
 145         inode_inc_link_count(inode);
 146         ihold(inode);
 147
 148         return exofs_add_nondir(dentry, inode);
 149 }
 150
 151 static int exofs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 152 {
 153         struct inode *inode;
 154         int err;
 155
 156         inode_inc_link_count(dir);
 157
 158         inode = exofs_new_inode(dir, S_IFDIR | mode);
 159         err = PTR_ERR(inode);
 160         if (IS_ERR(inode))
 161                 goto out_dir;
 162
 163         inode->i_op = &exofs_dir_inode_operations;
 164         inode->i_fop = &exofs_dir_operations;
 165         inode->i_mapping->a_ops = &exofs_aops;
 166
 167         inode_inc_link_count(inode);
 168
 169         err = exofs_make_empty(inode, dir);
 170         if (err)
 171                 goto out_fail;
 172
 173         err = exofs_add_link(dentry, inode);
 174         if (err)
 175                 goto out_fail;
 176
 177         d_instantiate(dentry, inode);
 178 out:
 179         return err;
 180
 181 out_fail:
 182         inode_dec_link_count(inode);
 183         inode_dec_link_count(inode);
 184         iput(inode);
 185 out_dir:
 186         inode_dec_link_count(dir);
 187         goto out;
 188 }
 189
 190 static int exofs_unlink(struct inode *dir, struct dentry *dentry)
 191 {
 192         struct inode *inode = d_inode(dentry);
 193         struct exofs_dir_entry *de;
 194         struct page *page;
 195         int err = -ENOENT;
 196
 197         de = exofs_find_entry(dir, dentry, &page);
 198         if (!de)
 199                 goto out;
 200
 201         err = exofs_delete_entry(de, page);
 202         if (err)
 203                 goto out;
 204
 205         inode->i_ctime = dir->i_ctime;
 206         inode_dec_link_count(inode);
 207         err = 0;
 208 out:
 209         return err;
 210 }
 211
 212 static int exofs_rmdir(struct inode *dir, struct dentry *dentry)
 213 {
 214         struct inode *inode = d_inode(dentry);
 215         int err = -ENOTEMPTY;
 216
 217         if (exofs_empty_dir(inode)) {
 218                 err = exofs_unlink(dir, dentry);
 219                 if (!err) {
 220                         inode->i_size = 0;
 221                         inode_dec_link_count(inode);
 222                         inode_dec_link_count(dir);
 223                 }
 224         }
 225         return err;
 226 }
 227
 228 static int exofs_rename(struct inode *old_dir, struct dentry *old_dentry,
 229                 struct inode *new_dir, struct dentry *new_dentry)
 230 {
 231         struct inode *old_inode = d_inode(old_dentry);
 232         struct inode *new_inode = d_inode(new_dentry);
 233         struct page *dir_page = NULL;
 234         struct exofs_dir_entry *dir_de = NULL;
 235         struct page *old_page;
 236         struct exofs_dir_entry *old_de;
 237         int err = -ENOENT;
 238
 239         old_de = exofs_find_entry(old_dir, old_dentry, &old_page);
 240         if (!old_de)
 241                 goto out;
 242
 243         if (S_ISDIR(old_inode->i_mode)) {
 244                 err = -EIO;
 245                 dir_de = exofs_dotdot(old_inode, &dir_page);
 246                 if (!dir_de)
 247                         goto out_old;
 248         }
 249
 250         if (new_inode) {
 251                 struct page *new_page;
 252                 struct exofs_dir_entry *new_de;
 253
 254                 err = -ENOTEMPTY;
 255                 if (dir_de && !exofs_empty_dir(new_inode))
 256                         goto out_dir;
 257
 258                 err = -ENOENT;
 259                 new_de = exofs_find_entry(new_dir, new_dentry, &new_page);
 260                 if (!new_de)
 261                         goto out_dir;
 262                 err = exofs_set_link(new_dir, new_de, new_page, old_inode);
 263                 new_inode->i_ctime = CURRENT_TIME;
 264                 if (dir_de)
 265                         drop_nlink(new_inode);
 266                 inode_dec_link_count(new_inode);
 267                 if (err)
 268                         goto out_dir;
 269         } else {
 270                 err = exofs_add_link(new_dentry, old_inode);
 271                 if (err)
 272                         goto out_dir;
 273                 if (dir_de)
 274                         inode_inc_link_count(new_dir);
 275         }
 276
 277         old_inode->i_ctime = CURRENT_TIME;
 278
 279         exofs_delete_entry(old_de, old_page);
 280         mark_inode_dirty(old_inode);
 281
 282         if (dir_de) {
 283                 err = exofs_set_link(old_inode, dir_de, dir_page, new_dir);
 284                 inode_dec_link_count(old_dir);
 285                 if (err)
 286                         goto out_dir;
 287         }
 288         return 0;
 289
 290
 291 out_dir:
 292         if (dir_de) {
 293                 kunmap(dir_page);
 294                 page_cache_release(dir_page);
 295         }
 296 out_old:
 297         kunmap(old_page);
 298         page_cache_release(old_page);
 299 out:
 300         return err;
 301 }
 302
 303 const struct inode_operations exofs_dir_inode_operations = {
 304         .create         = exofs_create,
 305         .lookup         = exofs_lookup,
 306         .link           = exofs_link,
 307         .unlink         = exofs_unlink,
 308         .symlink        = exofs_symlink,
 309         .mkdir          = exofs_mkdir,
 310         .rmdir          = exofs_rmdir,
 311         .mknod          = exofs_mknod,
 312         .rename         = exofs_rename,
 313         .setattr        = exofs_setattr,
 314 };
 315
 316 const struct inode_operations exofs_special_inode_operations = {
 317         .setattr        = exofs_setattr,
 318 };