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         if (!new_valid_dev(rdev))
  84                 return -EINVAL;
  85
  86         inode = exofs_new_inode(dir, mode);
  87         err = PTR_ERR(inode);
  88         if (!IS_ERR(inode)) {
  89                 init_special_inode(inode, inode->i_mode, rdev);
  90                 mark_inode_dirty(inode);
  91                 err = exofs_add_nondir(dentry, inode);
  92         }
  93         return err;
  94 }
  95
  96 static int exofs_symlink(struct inode *dir, struct dentry *dentry,
  97                           const char *symname)
  98 {
  99         struct super_block *sb = dir->i_sb;
 100         int err = -ENAMETOOLONG;
 101         unsigned l = strlen(symname)+1;
 102         struct inode *inode;
 103         struct exofs_i_info *oi;
 104
 105         if (l > sb->s_blocksize)
 106                 goto out;
 107
 108         inode = exofs_new_inode(dir, S_IFLNK | S_IRWXUGO);
 109         err = PTR_ERR(inode);
 110         if (IS_ERR(inode))
 111                 goto out;
 112
 113         oi = exofs_i(inode);
 114         if (l > sizeof(oi->i_data)) {
 115                 /* slow symlink */
 116                 inode->i_op = &page_symlink_inode_operations;
 117                 inode->i_mapping->a_ops = &exofs_aops;
 118                 memset(oi->i_data, 0, sizeof(oi->i_data));
 119
 120                 err = page_symlink(inode, symname, l);
 121                 if (err)
 122                         goto out_fail;
 123         } else {
 124                 /* fast symlink */
 125                 inode->i_op = &simple_symlink_inode_operations;
 126                 inode->i_link = (char *)oi->i_data;
 127                 memcpy(oi->i_data, symname, l);
 128                 inode->i_size = l-1;
 129         }
 130         mark_inode_dirty(inode);
 131
 132         err = exofs_add_nondir(dentry, inode);
 133 out:
 134         return err;
 135
 136 out_fail:
 137         inode_dec_link_count(inode);
 138         iput(inode);
 139         goto out;
 140 }
 141
 142 static int exofs_link(struct dentry *old_dentry, struct inode *dir,
 143                 struct dentry *dentry)
 144 {
 145         struct inode *inode = d_inode(old_dentry);
 146
 147         inode->i_ctime = CURRENT_TIME;
 148         inode_inc_link_count(inode);
 149         ihold(inode);
 150
 151         return exofs_add_nondir(dentry, inode);
 152 }
 153
 154 static int exofs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 155 {
 156         struct inode *inode;
 157         int err;
 158
 159         inode_inc_link_count(dir);
 160
 161         inode = exofs_new_inode(dir, S_IFDIR | mode);
 162         err = PTR_ERR(inode);
 163         if (IS_ERR(inode))
 164                 goto out_dir;
 165
 166         inode->i_op = &exofs_dir_inode_operations;
 167         inode->i_fop = &exofs_dir_operations;
 168         inode->i_mapping->a_ops = &exofs_aops;
 169
 170         inode_inc_link_count(inode);
 171
 172         err = exofs_make_empty(inode, dir);
 173         if (err)
 174                 goto out_fail;
 175
 176         err = exofs_add_link(dentry, inode);
 177         if (err)
 178                 goto out_fail;
 179
 180         d_instantiate(dentry, inode);
 181 out:
 182         return err;
 183
 184 out_fail:
 185         inode_dec_link_count(inode);
 186         inode_dec_link_count(inode);
 187         iput(inode);
 188 out_dir:
 189         inode_dec_link_count(dir);
 190         goto out;
 191 }
 192
 193 static int exofs_unlink(struct inode *dir, struct dentry *dentry)
 194 {
 195         struct inode *inode = d_inode(dentry);
 196         struct exofs_dir_entry *de;
 197         struct page *page;
 198         int err = -ENOENT;
 199
 200         de = exofs_find_entry(dir, dentry, &page);
 201         if (!de)
 202                 goto out;
 203
 204         err = exofs_delete_entry(de, page);
 205         if (err)
 206                 goto out;
 207
 208         inode->i_ctime = dir->i_ctime;
 209         inode_dec_link_count(inode);
 210         err = 0;
 211 out:
 212         return err;
 213 }
 214
 215 static int exofs_rmdir(struct inode *dir, struct dentry *dentry)
 216 {
 217         struct inode *inode = d_inode(dentry);
 218         int err = -ENOTEMPTY;
 219
 220         if (exofs_empty_dir(inode)) {
 221                 err = exofs_unlink(dir, dentry);
 222                 if (!err) {
 223                         inode->i_size = 0;
 224                         inode_dec_link_count(inode);
 225                         inode_dec_link_count(dir);
 226                 }
 227         }
 228         return err;
 229 }
 230
 231 static int exofs_rename(struct inode *old_dir, struct dentry *old_dentry,
 232                 struct inode *new_dir, struct dentry *new_dentry)
 233 {
 234         struct inode *old_inode = d_inode(old_dentry);
 235         struct inode *new_inode = d_inode(new_dentry);
 236         struct page *dir_page = NULL;
 237         struct exofs_dir_entry *dir_de = NULL;
 238         struct page *old_page;
 239         struct exofs_dir_entry *old_de;
 240         int err = -ENOENT;
 241
 242         old_de = exofs_find_entry(old_dir, old_dentry, &old_page);
 243         if (!old_de)
 244                 goto out;
 245
 246         if (S_ISDIR(old_inode->i_mode)) {
 247                 err = -EIO;
 248                 dir_de = exofs_dotdot(old_inode, &dir_page);
 249                 if (!dir_de)
 250                         goto out_old;
 251         }
 252
 253         if (new_inode) {
 254                 struct page *new_page;
 255                 struct exofs_dir_entry *new_de;
 256
 257                 err = -ENOTEMPTY;
 258                 if (dir_de && !exofs_empty_dir(new_inode))
 259                         goto out_dir;
 260
 261                 err = -ENOENT;
 262                 new_de = exofs_find_entry(new_dir, new_dentry, &new_page);
 263                 if (!new_de)
 264                         goto out_dir;
 265                 err = exofs_set_link(new_dir, new_de, new_page, old_inode);
 266                 new_inode->i_ctime = CURRENT_TIME;
 267                 if (dir_de)
 268                         drop_nlink(new_inode);
 269                 inode_dec_link_count(new_inode);
 270                 if (err)
 271                         goto out_dir;
 272         } else {
 273                 err = exofs_add_link(new_dentry, old_inode);
 274                 if (err)
 275                         goto out_dir;
 276                 if (dir_de)
 277                         inode_inc_link_count(new_dir);
 278         }
 279
 280         old_inode->i_ctime = CURRENT_TIME;
 281
 282         exofs_delete_entry(old_de, old_page);
 283         mark_inode_dirty(old_inode);
 284
 285         if (dir_de) {
 286                 err = exofs_set_link(old_inode, dir_de, dir_page, new_dir);
 287                 inode_dec_link_count(old_dir);
 288                 if (err)
 289                         goto out_dir;
 290         }
 291         return 0;
 292
 293
 294 out_dir:
 295         if (dir_de) {
 296                 kunmap(dir_page);
 297                 page_cache_release(dir_page);
 298         }
 299 out_old:
 300         kunmap(old_page);
 301         page_cache_release(old_page);
 302 out:
 303         return err;
 304 }
 305
 306 const struct inode_operations exofs_dir_inode_operations = {
 307         .create         = exofs_create,
 308         .lookup         = exofs_lookup,
 309         .link           = exofs_link,
 310         .unlink         = exofs_unlink,
 311         .symlink        = exofs_symlink,
 312         .mkdir          = exofs_mkdir,
 313         .rmdir          = exofs_rmdir,
 314         .mknod          = exofs_mknod,
 315         .rename         = exofs_rename,
 316         .setattr        = exofs_setattr,
 317 };
 318
 319 const struct inode_operations exofs_special_inode_operations = {
 320         .setattr        = exofs_setattr,
 321 };