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 = 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, int mode,
  63                          struct nameidata *nd)
  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, int 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 = &exofs_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 = &exofs_fast_symlink_inode_operations;
 126                 memcpy(oi->i_data, symname, l);
 127                 inode->i_size = l-1;
 128         }
 129         mark_inode_dirty(inode);
 130
 131         err = exofs_add_nondir(dentry, inode);
 132 out:
 133         return err;
 134
 135 out_fail:
 136         inode_dec_link_count(inode);
 137         iput(inode);
 138         goto out;
 139 }
 140
 141 static int exofs_link(struct dentry *old_dentry, struct inode *dir,
 142                 struct dentry *dentry)
 143 {
 144         struct inode *inode = old_dentry->d_inode;
 145
 146         if (inode->i_nlink >= EXOFS_LINK_MAX)
 147                 return -EMLINK;
 148
 149         inode->i_ctime = CURRENT_TIME;
 150         inode_inc_link_count(inode);
 151         ihold(inode);
 152
 153         return exofs_add_nondir(dentry, inode);
 154 }
 155
 156 static int exofs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 157 {
 158         struct inode *inode;
 159         int err = -EMLINK;
 160
 161         if (dir->i_nlink >= EXOFS_LINK_MAX)
 162                 goto out;
 163
 164         inode_inc_link_count(dir);
 165
 166         inode = exofs_new_inode(dir, S_IFDIR | mode);
 167         err = PTR_ERR(inode);
 168         if (IS_ERR(inode))
 169                 goto out_dir;
 170
 171         inode->i_op = &exofs_dir_inode_operations;
 172         inode->i_fop = &exofs_dir_operations;
 173         inode->i_mapping->a_ops = &exofs_aops;
 174
 175         inode_inc_link_count(inode);
 176
 177         err = exofs_make_empty(inode, dir);
 178         if (err)
 179                 goto out_fail;
 180
 181         err = exofs_add_link(dentry, inode);
 182         if (err)
 183                 goto out_fail;
 184
 185         d_instantiate(dentry, inode);
 186 out:
 187         return err;
 188
 189 out_fail:
 190         inode_dec_link_count(inode);
 191         inode_dec_link_count(inode);
 192         iput(inode);
 193 out_dir:
 194         inode_dec_link_count(dir);
 195         goto out;
 196 }
 197
 198 static int exofs_unlink(struct inode *dir, struct dentry *dentry)
 199 {
 200         struct inode *inode = dentry->d_inode;
 201         struct exofs_dir_entry *de;
 202         struct page *page;
 203         int err = -ENOENT;
 204
 205         de = exofs_find_entry(dir, dentry, &page);
 206         if (!de)
 207                 goto out;
 208
 209         err = exofs_delete_entry(de, page);
 210         if (err)
 211                 goto out;
 212
 213         inode->i_ctime = dir->i_ctime;
 214         inode_dec_link_count(inode);
 215         err = 0;
 216 out:
 217         return err;
 218 }
 219
 220 static int exofs_rmdir(struct inode *dir, struct dentry *dentry)
 221 {
 222         struct inode *inode = dentry->d_inode;
 223         int err = -ENOTEMPTY;
 224
 225         if (exofs_empty_dir(inode)) {
 226                 err = exofs_unlink(dir, dentry);
 227                 if (!err) {
 228                         inode->i_size = 0;
 229                         inode_dec_link_count(inode);
 230                         inode_dec_link_count(dir);
 231                 }
 232         }
 233         return err;
 234 }
 235
 236 static int exofs_rename(struct inode *old_dir, struct dentry *old_dentry,
 237                 struct inode *new_dir, struct dentry *new_dentry)
 238 {
 239         struct inode *old_inode = old_dentry->d_inode;
 240         struct inode *new_inode = new_dentry->d_inode;
 241         struct page *dir_page = NULL;
 242         struct exofs_dir_entry *dir_de = NULL;
 243         struct page *old_page;
 244         struct exofs_dir_entry *old_de;
 245         int err = -ENOENT;
 246
 247         old_de = exofs_find_entry(old_dir, old_dentry, &old_page);
 248         if (!old_de)
 249                 goto out;
 250
 251         if (S_ISDIR(old_inode->i_mode)) {
 252                 err = -EIO;
 253                 dir_de = exofs_dotdot(old_inode, &dir_page);
 254                 if (!dir_de)
 255                         goto out_old;
 256         }
 257
 258         if (new_inode) {
 259                 struct page *new_page;
 260                 struct exofs_dir_entry *new_de;
 261
 262                 err = -ENOTEMPTY;
 263                 if (dir_de && !exofs_empty_dir(new_inode))
 264                         goto out_dir;
 265
 266                 err = -ENOENT;
 267                 new_de = exofs_find_entry(new_dir, new_dentry, &new_page);
 268                 if (!new_de)
 269                         goto out_dir;
 270                 err = exofs_set_link(new_dir, new_de, new_page, old_inode);
 271                 new_inode->i_ctime = CURRENT_TIME;
 272                 if (dir_de)
 273                         drop_nlink(new_inode);
 274                 inode_dec_link_count(new_inode);
 275                 if (err)
 276                         goto out_dir;
 277         } else {
 278                 if (dir_de) {
 279                         err = -EMLINK;
 280                         if (new_dir->i_nlink >= EXOFS_LINK_MAX)
 281                                 goto out_dir;
 282                 }
 283                 err = exofs_add_link(new_dentry, old_inode);
 284                 if (err)
 285                         goto out_dir;
 286                 if (dir_de)
 287                         inode_inc_link_count(new_dir);
 288         }
 289
 290         old_inode->i_ctime = CURRENT_TIME;
 291
 292         exofs_delete_entry(old_de, old_page);
 293         mark_inode_dirty(old_inode);
 294
 295         if (dir_de) {
 296                 err = exofs_set_link(old_inode, dir_de, dir_page, new_dir);
 297                 inode_dec_link_count(old_dir);
 298                 if (err)
 299                         goto out_dir;
 300         }
 301         return 0;
 302
 303
 304 out_dir:
 305         if (dir_de) {
 306                 kunmap(dir_page);
 307                 page_cache_release(dir_page);
 308         }
 309 out_old:
 310         kunmap(old_page);
 311         page_cache_release(old_page);
 312 out:
 313         return err;
 314 }
 315
 316 const struct inode_operations exofs_dir_inode_operations = {
 317         .create         = exofs_create,
 318         .lookup         = exofs_lookup,
 319         .link           = exofs_link,
 320         .unlink         = exofs_unlink,
 321         .symlink        = exofs_symlink,
 322         .mkdir          = exofs_mkdir,
 323         .rmdir          = exofs_rmdir,
 324         .mknod          = exofs_mknod,
 325         .rename         = exofs_rename,
 326         .setattr        = exofs_setattr,
 327 };
 328
 329 const struct inode_operations exofs_special_inode_operations = {
 330         .setattr        = exofs_setattr,
 331 };