fs/exofs/namei.c

   1 /*
   2  * Copyright (C) 2005, 2006
   3  * Avishay Traeger (avishay@gmail.com) (avishay@il.ibm.com)
   4  * Copyright (C) 2005, 2006
   5  * International Business Machines
   6  * Copyright (C) 2008, 2009
   7  * Boaz Harrosh <bharrosh@panasas.com>
   8  *
   9  * Copyrights for code taken from ext2:
  10  *     Copyright (C) 1992, 1993, 1994, 1995
  11  *     Remy Card (card@masi.ibp.fr)
  12  *     Laboratoire MASI - Institut Blaise Pascal
  13  *     Universite Pierre et Marie Curie (Paris VI)
  14  *     from
  15  *     linux/fs/minix/inode.c
  16  *     Copyright (C) 1991, 1992  Linus Torvalds
  17  *
  18  * This file is part of exofs.
  19  *
  20  * exofs is free software; you can redistribute it and/or modify
  21  * it under the terms of the GNU General Public License as published by
  22  * the Free Software Foundation.  Since it is based on ext2, and the only
  23  * valid version of GPL for the Linux kernel is version 2, the only valid
  24  * version of GPL for exofs is version 2.
  25  *
  26  * exofs is distributed in the hope that it will be useful,
  27  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  28  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  29  * GNU General Public License for more details.
  30  *
  31  * You should have received a copy of the GNU General Public License
  32  * along with exofs; if not, write to the Free Software
  33  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  34  */
  35
  36 #include "exofs.h"
  37
  38 static inline int exofs_add_nondir(struct dentry *dentry, struct inode *inode)
  39 {
  40         int err = exofs_add_link(dentry, inode);
  41         if (!err) {
  42                 d_instantiate(dentry, inode);
  43                 return 0;
  44         }
  45         inode_dec_link_count(inode);
  46         iput(inode);
  47         return err;
  48 }
  49
  50 static struct dentry *exofs_lookup(struct inode *dir, struct dentry *dentry,
  51                                    struct nameidata *nd)
  52 {
  53         struct inode *inode;
  54         ino_t ino;
  55
  56         if (dentry->d_name.len > EXOFS_NAME_LEN)
  57                 return ERR_PTR(-ENAMETOOLONG);
  58
  59         ino = exofs_inode_by_name(dir, dentry);
  60         inode = NULL;
  61         if (ino) {
  62                 inode = exofs_iget(dir->i_sb, ino);
  63                 if (IS_ERR(inode))
  64                         return ERR_CAST(inode);
  65         }
  66         return d_splice_alias(inode, dentry);
  67 }
  68
  69 static int exofs_create(struct inode *dir, struct dentry *dentry, int mode,
  70                          struct nameidata *nd)
  71 {
  72         struct inode *inode = exofs_new_inode(dir, mode);
  73         int err = PTR_ERR(inode);
  74         if (!IS_ERR(inode)) {
  75                 inode->i_op = &exofs_file_inode_operations;
  76                 inode->i_fop = &exofs_file_operations;
  77                 inode->i_mapping->a_ops = &exofs_aops;
  78                 mark_inode_dirty(inode);
  79                 err = exofs_add_nondir(dentry, inode);
  80         }
  81         return err;
  82 }
  83
  84 static int exofs_mknod(struct inode *dir, struct dentry *dentry, int mode,
  85                        dev_t rdev)
  86 {
  87         struct inode *inode;
  88         int err;
  89
  90         if (!new_valid_dev(rdev))
  91                 return -EINVAL;
  92
  93         inode = exofs_new_inode(dir, mode);
  94         err = PTR_ERR(inode);
  95         if (!IS_ERR(inode)) {
  96                 init_special_inode(inode, inode->i_mode, rdev);
  97                 mark_inode_dirty(inode);
  98                 err = exofs_add_nondir(dentry, inode);
  99         }
 100         return err;
 101 }
 102
 103 static int exofs_symlink(struct inode *dir, struct dentry *dentry,
 104                           const char *symname)
 105 {
 106         struct super_block *sb = dir->i_sb;
 107         int err = -ENAMETOOLONG;
 108         unsigned l = strlen(symname)+1;
 109         struct inode *inode;
 110         struct exofs_i_info *oi;
 111
 112         if (l > sb->s_blocksize)
 113                 goto out;
 114
 115         inode = exofs_new_inode(dir, S_IFLNK | S_IRWXUGO);
 116         err = PTR_ERR(inode);
 117         if (IS_ERR(inode))
 118                 goto out;
 119
 120         oi = exofs_i(inode);
 121         if (l > sizeof(oi->i_data)) {
 122                 /* slow symlink */
 123                 inode->i_op = &exofs_symlink_inode_operations;
 124                 inode->i_mapping->a_ops = &exofs_aops;
 125                 memset(oi->i_data, 0, sizeof(oi->i_data));
 126
 127                 err = page_symlink(inode, symname, l);
 128                 if (err)
 129                         goto out_fail;
 130         } else {
 131                 /* fast symlink */
 132                 inode->i_op = &exofs_fast_symlink_inode_operations;
 133                 memcpy(oi->i_data, symname, l);
 134                 inode->i_size = l-1;
 135         }
 136         mark_inode_dirty(inode);
 137
 138         err = exofs_add_nondir(dentry, inode);
 139 out:
 140         return err;
 141
 142 out_fail:
 143         inode_dec_link_count(inode);
 144         iput(inode);
 145         goto out;
 146 }
 147
 148 static int exofs_link(struct dentry *old_dentry, struct inode *dir,
 149                 struct dentry *dentry)
 150 {
 151         struct inode *inode = old_dentry->d_inode;
 152
 153         if (inode->i_nlink >= EXOFS_LINK_MAX)
 154                 return -EMLINK;
 155
 156         inode->i_ctime = CURRENT_TIME;
 157         inode_inc_link_count(inode);
 158         atomic_inc(&inode->i_count);
 159
 160         return exofs_add_nondir(dentry, inode);
 161 }
 162
 163 static int exofs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 164 {
 165         struct inode *inode;
 166         int err = -EMLINK;
 167
 168         if (dir->i_nlink >= EXOFS_LINK_MAX)
 169                 goto out;
 170
 171         inode_inc_link_count(dir);
 172
 173         inode = exofs_new_inode(dir, S_IFDIR | mode);
 174         err = PTR_ERR(inode);
 175         if (IS_ERR(inode))
 176                 goto out_dir;
 177
 178         inode->i_op = &exofs_dir_inode_operations;
 179         inode->i_fop = &exofs_dir_operations;
 180         inode->i_mapping->a_ops = &exofs_aops;
 181
 182         inode_inc_link_count(inode);
 183
 184         err = exofs_make_empty(inode, dir);
 185         if (err)
 186                 goto out_fail;
 187
 188         err = exofs_add_link(dentry, inode);
 189         if (err)
 190                 goto out_fail;
 191
 192         d_instantiate(dentry, inode);
 193 out:
 194         return err;
 195
 196 out_fail:
 197         inode_dec_link_count(inode);
 198         inode_dec_link_count(inode);
 199         iput(inode);
 200 out_dir:
 201         inode_dec_link_count(dir);
 202         goto out;
 203 }
 204
 205 static int exofs_unlink(struct inode *dir, struct dentry *dentry)
 206 {
 207         struct inode *inode = dentry->d_inode;
 208         struct exofs_dir_entry *de;
 209         struct page *page;
 210         int err = -ENOENT;
 211
 212         de = exofs_find_entry(dir, dentry, &page);
 213         if (!de)
 214                 goto out;
 215
 216         err = exofs_delete_entry(de, page);
 217         if (err)
 218                 goto out;
 219
 220         inode->i_ctime = dir->i_ctime;
 221         inode_dec_link_count(inode);
 222         err = 0;
 223 out:
 224         return err;
 225 }
 226
 227 static int exofs_rmdir(struct inode *dir, struct dentry *dentry)
 228 {
 229         struct inode *inode = dentry->d_inode;
 230         int err = -ENOTEMPTY;
 231
 232         if (exofs_empty_dir(inode)) {
 233                 err = exofs_unlink(dir, dentry);
 234                 if (!err) {
 235                         inode->i_size = 0;
 236                         inode_dec_link_count(inode);
 237                         inode_dec_link_count(dir);
 238                 }
 239         }
 240         return err;
 241 }
 242
 243 static int exofs_rename(struct inode *old_dir, struct dentry *old_dentry,
 244                 struct inode *new_dir, struct dentry *new_dentry)
 245 {
 246         struct inode *old_inode = old_dentry->d_inode;
 247         struct inode *new_inode = new_dentry->d_inode;
 248         struct page *dir_page = NULL;
 249         struct exofs_dir_entry *dir_de = NULL;
 250         struct page *old_page;
 251         struct exofs_dir_entry *old_de;
 252         int err = -ENOENT;
 253
 254         old_de = exofs_find_entry(old_dir, old_dentry, &old_page);
 255         if (!old_de)
 256                 goto out;
 257
 258         if (S_ISDIR(old_inode->i_mode)) {
 259                 err = -EIO;
 260                 dir_de = exofs_dotdot(old_inode, &dir_page);
 261                 if (!dir_de)
 262                         goto out_old;
 263         }
 264
 265         if (new_inode) {
 266                 struct page *new_page;
 267                 struct exofs_dir_entry *new_de;
 268
 269                 err = -ENOTEMPTY;
 270                 if (dir_de && !exofs_empty_dir(new_inode))
 271                         goto out_dir;
 272
 273                 err = -ENOENT;
 274                 new_de = exofs_find_entry(new_dir, new_dentry, &new_page);
 275                 if (!new_de)
 276                         goto out_dir;
 277                 inode_inc_link_count(old_inode);
 278                 err = exofs_set_link(new_dir, new_de, new_page, old_inode);
 279                 new_inode->i_ctime = CURRENT_TIME;
 280                 if (dir_de)
 281                         drop_nlink(new_inode);
 282                 inode_dec_link_count(new_inode);
 283                 if (err)
 284                         goto out_dir;
 285         } else {
 286                 if (dir_de) {
 287                         err = -EMLINK;
 288                         if (new_dir->i_nlink >= EXOFS_LINK_MAX)
 289                                 goto out_dir;
 290                 }
 291                 inode_inc_link_count(old_inode);
 292                 err = exofs_add_link(new_dentry, old_inode);
 293                 if (err) {
 294                         inode_dec_link_count(old_inode);
 295                         goto out_dir;
 296                 }
 297                 if (dir_de)
 298                         inode_inc_link_count(new_dir);
 299         }
 300
 301         old_inode->i_ctime = CURRENT_TIME;
 302
 303         exofs_delete_entry(old_de, old_page);
 304         inode_dec_link_count(old_inode);
 305
 306         if (dir_de) {
 307                 err = exofs_set_link(old_inode, dir_de, dir_page, new_dir);
 308                 inode_dec_link_count(old_dir);
 309                 if (err)
 310                         goto out_dir;
 311         }
 312         return 0;
 313
 314
 315 out_dir:
 316         if (dir_de) {
 317                 kunmap(dir_page);
 318                 page_cache_release(dir_page);
 319         }
 320 out_old:
 321         kunmap(old_page);
 322         page_cache_release(old_page);
 323 out:
 324         return err;
 325 }
 326
 327 const struct inode_operations exofs_dir_inode_operations = {
 328         .create         = exofs_create,
 329         .lookup         = exofs_lookup,
 330         .link           = exofs_link,
 331         .unlink         = exofs_unlink,
 332         .symlink        = exofs_symlink,
 333         .mkdir          = exofs_mkdir,
 334         .rmdir          = exofs_rmdir,
 335         .mknod          = exofs_mknod,
 336         .rename         = exofs_rename,
 337         .setattr        = exofs_setattr,
 338 };
 339
 340 const struct inode_operations exofs_special_inode_operations = {
 341         .setattr        = exofs_setattr,
 342 };