fs/exofs/namei.c

   1 /*
   2  * Copyright (C) 2005, 2006
   3  * Avishay Traeger (avishay@gmail.com)
   4  * Copyright (C) 2008, 2009
   5  * Boaz Harrosh <bharrosh@panasas.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                                    struct nameidata *nd)
  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 = NULL;
  59         if (ino) {
  60                 inode = exofs_iget(dir->i_sb, ino);
  61                 if (IS_ERR(inode))
  62                         return ERR_CAST(inode);
  63         }
  64         return d_splice_alias(inode, dentry);
  65 }
  66
  67 static int exofs_create(struct inode *dir, struct dentry *dentry, int mode,
  68                          struct nameidata *nd)
  69 {
  70         struct inode *inode = exofs_new_inode(dir, mode);
  71         int err = PTR_ERR(inode);
  72         if (!IS_ERR(inode)) {
  73                 inode->i_op = &exofs_file_inode_operations;
  74                 inode->i_fop = &exofs_file_operations;
  75                 inode->i_mapping->a_ops = &exofs_aops;
  76                 mark_inode_dirty(inode);
  77                 err = exofs_add_nondir(dentry, inode);
  78         }
  79         return err;
  80 }
  81
  82 static int exofs_mknod(struct inode *dir, struct dentry *dentry, int mode,
  83                        dev_t rdev)
  84 {
  85         struct inode *inode;
  86         int err;
  87
  88         if (!new_valid_dev(rdev))
  89                 return -EINVAL;
  90
  91         inode = exofs_new_inode(dir, mode);
  92         err = PTR_ERR(inode);
  93         if (!IS_ERR(inode)) {
  94                 init_special_inode(inode, inode->i_mode, rdev);
  95                 mark_inode_dirty(inode);
  96                 err = exofs_add_nondir(dentry, inode);
  97         }
  98         return err;
  99 }
 100
 101 static int exofs_symlink(struct inode *dir, struct dentry *dentry,
 102                           const char *symname)
 103 {
 104         struct super_block *sb = dir->i_sb;
 105         int err = -ENAMETOOLONG;
 106         unsigned l = strlen(symname)+1;
 107         struct inode *inode;
 108         struct exofs_i_info *oi;
 109
 110         if (l > sb->s_blocksize)
 111                 goto out;
 112
 113         inode = exofs_new_inode(dir, S_IFLNK | S_IRWXUGO);
 114         err = PTR_ERR(inode);
 115         if (IS_ERR(inode))
 116                 goto out;
 117
 118         oi = exofs_i(inode);
 119         if (l > sizeof(oi->i_data)) {
 120                 /* slow symlink */
 121                 inode->i_op = &exofs_symlink_inode_operations;
 122                 inode->i_mapping->a_ops = &exofs_aops;
 123                 memset(oi->i_data, 0, sizeof(oi->i_data));
 124
 125                 err = page_symlink(inode, symname, l);
 126                 if (err)
 127                         goto out_fail;
 128         } else {
 129                 /* fast symlink */
 130                 inode->i_op = &exofs_fast_symlink_inode_operations;
 131                 memcpy(oi->i_data, symname, l);
 132                 inode->i_size = l-1;
 133         }
 134         mark_inode_dirty(inode);
 135
 136         err = exofs_add_nondir(dentry, inode);
 137 out:
 138         return err;
 139
 140 out_fail:
 141         inode_dec_link_count(inode);
 142         iput(inode);
 143         goto out;
 144 }
 145
 146 static int exofs_link(struct dentry *old_dentry, struct inode *dir,
 147                 struct dentry *dentry)
 148 {
 149         struct inode *inode = old_dentry->d_inode;
 150
 151         if (inode->i_nlink >= EXOFS_LINK_MAX)
 152                 return -EMLINK;
 153
 154         inode->i_ctime = CURRENT_TIME;
 155         inode_inc_link_count(inode);
 156         atomic_inc(&inode->i_count);
 157
 158         return exofs_add_nondir(dentry, inode);
 159 }
 160
 161 static int exofs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 162 {
 163         struct inode *inode;
 164         int err = -EMLINK;
 165
 166         if (dir->i_nlink >= EXOFS_LINK_MAX)
 167                 goto out;
 168
 169         inode_inc_link_count(dir);
 170
 171         inode = exofs_new_inode(dir, S_IFDIR | mode);
 172         err = PTR_ERR(inode);
 173         if (IS_ERR(inode))
 174                 goto out_dir;
 175
 176         inode->i_op = &exofs_dir_inode_operations;
 177         inode->i_fop = &exofs_dir_operations;
 178         inode->i_mapping->a_ops = &exofs_aops;
 179
 180         inode_inc_link_count(inode);
 181
 182         err = exofs_make_empty(inode, dir);
 183         if (err)
 184                 goto out_fail;
 185
 186         err = exofs_add_link(dentry, inode);
 187         if (err)
 188                 goto out_fail;
 189
 190         d_instantiate(dentry, inode);
 191 out:
 192         return err;
 193
 194 out_fail:
 195         inode_dec_link_count(inode);
 196         inode_dec_link_count(inode);
 197         iput(inode);
 198 out_dir:
 199         inode_dec_link_count(dir);
 200         goto out;
 201 }
 202
 203 static int exofs_unlink(struct inode *dir, struct dentry *dentry)
 204 {
 205         struct inode *inode = dentry->d_inode;
 206         struct exofs_dir_entry *de;
 207         struct page *page;
 208         int err = -ENOENT;
 209
 210         de = exofs_find_entry(dir, dentry, &page);
 211         if (!de)
 212                 goto out;
 213
 214         err = exofs_delete_entry(de, page);
 215         if (err)
 216                 goto out;
 217
 218         inode->i_ctime = dir->i_ctime;
 219         inode_dec_link_count(inode);
 220         err = 0;
 221 out:
 222         return err;
 223 }
 224
 225 static int exofs_rmdir(struct inode *dir, struct dentry *dentry)
 226 {
 227         struct inode *inode = dentry->d_inode;
 228         int err = -ENOTEMPTY;
 229
 230         if (exofs_empty_dir(inode)) {
 231                 err = exofs_unlink(dir, dentry);
 232                 if (!err) {
 233                         inode->i_size = 0;
 234                         inode_dec_link_count(inode);
 235                         inode_dec_link_count(dir);
 236                 }
 237         }
 238         return err;
 239 }
 240
 241 static int exofs_rename(struct inode *old_dir, struct dentry *old_dentry,
 242                 struct inode *new_dir, struct dentry *new_dentry)
 243 {
 244         struct inode *old_inode = old_dentry->d_inode;
 245         struct inode *new_inode = new_dentry->d_inode;
 246         struct page *dir_page = NULL;
 247         struct exofs_dir_entry *dir_de = NULL;
 248         struct page *old_page;
 249         struct exofs_dir_entry *old_de;
 250         int err = -ENOENT;
 251
 252         old_de = exofs_find_entry(old_dir, old_dentry, &old_page);
 253         if (!old_de)
 254                 goto out;
 255
 256         if (S_ISDIR(old_inode->i_mode)) {
 257                 err = -EIO;
 258                 dir_de = exofs_dotdot(old_inode, &dir_page);
 259                 if (!dir_de)
 260                         goto out_old;
 261         }
 262
 263         if (new_inode) {
 264                 struct page *new_page;
 265                 struct exofs_dir_entry *new_de;
 266
 267                 err = -ENOTEMPTY;
 268                 if (dir_de && !exofs_empty_dir(new_inode))
 269                         goto out_dir;
 270
 271                 err = -ENOENT;
 272                 new_de = exofs_find_entry(new_dir, new_dentry, &new_page);
 273                 if (!new_de)
 274                         goto out_dir;
 275                 inode_inc_link_count(old_inode);
 276                 err = exofs_set_link(new_dir, new_de, new_page, old_inode);
 277                 new_inode->i_ctime = CURRENT_TIME;
 278                 if (dir_de)
 279                         drop_nlink(new_inode);
 280                 inode_dec_link_count(new_inode);
 281                 if (err)
 282                         goto out_dir;
 283         } else {
 284                 if (dir_de) {
 285                         err = -EMLINK;
 286                         if (new_dir->i_nlink >= EXOFS_LINK_MAX)
 287                                 goto out_dir;
 288                 }
 289                 inode_inc_link_count(old_inode);
 290                 err = exofs_add_link(new_dentry, old_inode);
 291                 if (err) {
 292                         inode_dec_link_count(old_inode);
 293                         goto out_dir;
 294                 }
 295                 if (dir_de)
 296                         inode_inc_link_count(new_dir);
 297         }
 298
 299         old_inode->i_ctime = CURRENT_TIME;
 300
 301         exofs_delete_entry(old_de, old_page);
 302         inode_dec_link_count(old_inode);
 303
 304         if (dir_de) {
 305                 err = exofs_set_link(old_inode, dir_de, dir_page, new_dir);
 306                 inode_dec_link_count(old_dir);
 307                 if (err)
 308                         goto out_dir;
 309         }
 310         return 0;
 311
 312
 313 out_dir:
 314         if (dir_de) {
 315                 kunmap(dir_page);
 316                 page_cache_release(dir_page);
 317         }
 318 out_old:
 319         kunmap(old_page);
 320         page_cache_release(old_page);
 321 out:
 322         return err;
 323 }
 324
 325 const struct inode_operations exofs_dir_inode_operations = {
 326         .create         = exofs_create,
 327         .lookup         = exofs_lookup,
 328         .link           = exofs_link,
 329         .unlink         = exofs_unlink,
 330         .symlink        = exofs_symlink,
 331         .mkdir          = exofs_mkdir,
 332         .rmdir          = exofs_rmdir,
 333         .mknod          = exofs_mknod,
 334         .rename         = exofs_rename,
 335         .setattr        = exofs_setattr,
 336 };
 337
 338 const struct inode_operations exofs_special_inode_operations = {
 339         .setattr        = exofs_setattr,
 340 };