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_nohighmem(inode);
 115                 inode->i_mapping->a_ops = &exofs_aops;
 116                 memset(oi->i_data, 0, sizeof(oi->i_data));
 117
 118                 err = page_symlink(inode, symname, l);
 119                 if (err)
 120                         goto out_fail;
 121         } else {
 122                 /* fast symlink */
 123                 inode->i_op = &simple_symlink_inode_operations;
 124                 inode->i_link = (char *)oi->i_data;
 125                 memcpy(oi->i_data, symname, l);
 126                 inode->i_size = l-1;
 127         }
 128         mark_inode_dirty(inode);
 129
 130         err = exofs_add_nondir(dentry, inode);
 131 out:
 132         return err;
 133
 134 out_fail:
 135         inode_dec_link_count(inode);
 136         iput(inode);
 137         goto out;
 138 }
 139
 140 static int exofs_link(struct dentry *old_dentry, struct inode *dir,
 141                 struct dentry *dentry)
 142 {
 143         struct inode *inode = d_inode(old_dentry);
 144
 145         inode->i_ctime = CURRENT_TIME;
 146         inode_inc_link_count(inode);
 147         ihold(inode);
 148
 149         return exofs_add_nondir(dentry, inode);
 150 }
 151
 152 static int exofs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 153 {
 154         struct inode *inode;
 155         int err;
 156
 157         inode_inc_link_count(dir);
 158
 159         inode = exofs_new_inode(dir, S_IFDIR | mode);
 160         err = PTR_ERR(inode);
 161         if (IS_ERR(inode))
 162                 goto out_dir;
 163
 164         inode->i_op = &exofs_dir_inode_operations;
 165         inode->i_fop = &exofs_dir_operations;
 166         inode->i_mapping->a_ops = &exofs_aops;
 167
 168         inode_inc_link_count(inode);
 169
 170         err = exofs_make_empty(inode, dir);
 171         if (err)
 172                 goto out_fail;
 173
 174         err = exofs_add_link(dentry, inode);
 175         if (err)
 176                 goto out_fail;
 177
 178         d_instantiate(dentry, inode);
 179 out:
 180         return err;
 181
 182 out_fail:
 183         inode_dec_link_count(inode);
 184         inode_dec_link_count(inode);
 185         iput(inode);
 186 out_dir:
 187         inode_dec_link_count(dir);
 188         goto out;
 189 }
 190
 191 static int exofs_unlink(struct inode *dir, struct dentry *dentry)
 192 {
 193         struct inode *inode = d_inode(dentry);
 194         struct exofs_dir_entry *de;
 195         struct page *page;
 196         int err = -ENOENT;
 197
 198         de = exofs_find_entry(dir, dentry, &page);
 199         if (!de)
 200                 goto out;
 201
 202         err = exofs_delete_entry(de, page);
 203         if (err)
 204                 goto out;
 205
 206         inode->i_ctime = dir->i_ctime;
 207         inode_dec_link_count(inode);
 208         err = 0;
 209 out:
 210         return err;
 211 }
 212
 213 static int exofs_rmdir(struct inode *dir, struct dentry *dentry)
 214 {
 215         struct inode *inode = d_inode(dentry);
 216         int err = -ENOTEMPTY;
 217
 218         if (exofs_empty_dir(inode)) {
 219                 err = exofs_unlink(dir, dentry);
 220                 if (!err) {
 221                         inode->i_size = 0;
 222                         inode_dec_link_count(inode);
 223                         inode_dec_link_count(dir);
 224                 }
 225         }
 226         return err;
 227 }
 228
 229 static int exofs_rename(struct inode *old_dir, struct dentry *old_dentry,
 230                 struct inode *new_dir, struct dentry *new_dentry)
 231 {
 232         struct inode *old_inode = d_inode(old_dentry);
 233         struct inode *new_inode = d_inode(new_dentry);
 234         struct page *dir_page = NULL;
 235         struct exofs_dir_entry *dir_de = NULL;
 236         struct page *old_page;
 237         struct exofs_dir_entry *old_de;
 238         int err = -ENOENT;
 239
 240         old_de = exofs_find_entry(old_dir, old_dentry, &old_page);
 241         if (!old_de)
 242                 goto out;
 243
 244         if (S_ISDIR(old_inode->i_mode)) {
 245                 err = -EIO;
 246                 dir_de = exofs_dotdot(old_inode, &dir_page);
 247                 if (!dir_de)
 248                         goto out_old;
 249         }
 250
 251         if (new_inode) {
 252                 struct page *new_page;
 253                 struct exofs_dir_entry *new_de;
 254
 255                 err = -ENOTEMPTY;
 256                 if (dir_de && !exofs_empty_dir(new_inode))
 257                         goto out_dir;
 258
 259                 err = -ENOENT;
 260                 new_de = exofs_find_entry(new_dir, new_dentry, &new_page);
 261                 if (!new_de)
 262                         goto out_dir;
 263                 err = exofs_set_link(new_dir, new_de, new_page, old_inode);
 264                 new_inode->i_ctime = CURRENT_TIME;
 265                 if (dir_de)
 266                         drop_nlink(new_inode);
 267                 inode_dec_link_count(new_inode);
 268                 if (err)
 269                         goto out_dir;
 270         } else {
 271                 err = exofs_add_link(new_dentry, old_inode);
 272                 if (err)
 273                         goto out_dir;
 274                 if (dir_de)
 275                         inode_inc_link_count(new_dir);
 276         }
 277
 278         old_inode->i_ctime = CURRENT_TIME;
 279
 280         exofs_delete_entry(old_de, old_page);
 281         mark_inode_dirty(old_inode);
 282
 283         if (dir_de) {
 284                 err = exofs_set_link(old_inode, dir_de, dir_page, new_dir);
 285                 inode_dec_link_count(old_dir);
 286                 if (err)
 287                         goto out_dir;
 288         }
 289         return 0;
 290
 291
 292 out_dir:
 293         if (dir_de) {
 294                 kunmap(dir_page);
 295                 page_cache_release(dir_page);
 296         }
 297 out_old:
 298         kunmap(old_page);
 299         page_cache_release(old_page);
 300 out:
 301         return err;
 302 }
 303
 304 const struct inode_operations exofs_dir_inode_operations = {
 305         .create         = exofs_create,
 306         .lookup         = exofs_lookup,
 307         .link           = exofs_link,
 308         .unlink         = exofs_unlink,
 309         .symlink        = exofs_symlink,
 310         .mkdir          = exofs_mkdir,
 311         .rmdir          = exofs_rmdir,
 312         .mknod          = exofs_mknod,
 313         .rename         = exofs_rename,
 314         .setattr        = exofs_setattr,
 315 };
 316
 317 const struct inode_operations exofs_special_inode_operations = {
 318         .setattr        = exofs_setattr,
 319 };