fs/nilfs2/namei.c

   1 /*
   2  * namei.c - NILFS pathname lookup operations.
   3  *
   4  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  *
  20  * Modified for NILFS by Amagai Yoshiji <amagai@osrg.net>,
  21  *                       Ryusuke Konishi <ryusuke@osrg.net>
  22  */
  23 /*
  24  *  linux/fs/ext2/namei.c
  25  *
  26  * Copyright (C) 1992, 1993, 1994, 1995
  27  * Remy Card (card@masi.ibp.fr)
  28  * Laboratoire MASI - Institut Blaise Pascal
  29  * Universite Pierre et Marie Curie (Paris VI)
  30  *
  31  *  from
  32  *
  33  *  linux/fs/minix/namei.c
  34  *
  35  *  Copyright (C) 1991, 1992  Linus Torvalds
  36  *
  37  *  Big-endian to little-endian byte-swapping/bitmaps by
  38  *        David S. Miller (davem@caip.rutgers.edu), 1995
  39  */
  40
  41 #include <linux/pagemap.h>
  42 #include "nilfs.h"
  43
  44
  45 static inline int nilfs_add_nondir(struct dentry *dentry, struct inode *inode)
  46 {
  47         int err = nilfs_add_link(dentry, inode);
  48         if (!err) {
  49                 d_instantiate(dentry, inode);
  50                 return 0;
  51         }
  52         inode_dec_link_count(inode);
  53         iput(inode);
  54         return err;
  55 }
  56
  57 /*
  58  * Methods themselves.
  59  */
  60
  61 static struct dentry *
  62 nilfs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
  63 {
  64         struct inode *inode;
  65         ino_t ino;
  66
  67         if (dentry->d_name.len > NILFS_NAME_LEN)
  68                 return ERR_PTR(-ENAMETOOLONG);
  69
  70         ino = nilfs_inode_by_name(dir, dentry);
  71         inode = NULL;
  72         if (ino) {
  73                 inode = nilfs_iget(dir->i_sb, ino);
  74                 if (IS_ERR(inode))
  75                         return ERR_CAST(inode);
  76         }
  77         return d_splice_alias(inode, dentry);
  78 }
  79
  80 struct dentry *nilfs_get_parent(struct dentry *child)
  81 {
  82         unsigned long ino;
  83         struct inode *inode;
  84         struct dentry dotdot;
  85
  86         dotdot.d_name.name = "..";
  87         dotdot.d_name.len = 2;
  88
  89         ino = nilfs_inode_by_name(child->d_inode, &dotdot);
  90         if (!ino)
  91                 return ERR_PTR(-ENOENT);
  92
  93         inode = nilfs_iget(child->d_inode->i_sb, ino);
  94         if (IS_ERR(inode))
  95                 return ERR_CAST(inode);
  96         return d_obtain_alias(inode);
  97 }
  98
  99 /*
 100  * By the time this is called, we already have created
 101  * the directory cache entry for the new file, but it
 102  * is so far negative - it has no inode.
 103  *
 104  * If the create succeeds, we fill in the inode information
 105  * with d_instantiate().
 106  */
 107 static int nilfs_create(struct inode *dir, struct dentry *dentry, int mode,
 108                         struct nameidata *nd)
 109 {
 110         struct inode *inode;
 111         struct nilfs_transaction_info ti;
 112         int err;
 113
 114         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 115         if (err)
 116                 return err;
 117         inode = nilfs_new_inode(dir, mode);
 118         err = PTR_ERR(inode);
 119         if (!IS_ERR(inode)) {
 120                 inode->i_op = &nilfs_file_inode_operations;
 121                 inode->i_fop = &nilfs_file_operations;
 122                 inode->i_mapping->a_ops = &nilfs_aops;
 123                 mark_inode_dirty(inode);
 124                 err = nilfs_add_nondir(dentry, inode);
 125         }
 126         if (!err)
 127                 err = nilfs_transaction_commit(dir->i_sb);
 128         else
 129                 nilfs_transaction_abort(dir->i_sb);
 130
 131         return err;
 132 }
 133
 134 static int
 135 nilfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
 136 {
 137         struct inode *inode;
 138         struct nilfs_transaction_info ti;
 139         int err;
 140
 141         if (!new_valid_dev(rdev))
 142                 return -EINVAL;
 143
 144         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 145         if (err)
 146                 return err;
 147         inode = nilfs_new_inode(dir, mode);
 148         err = PTR_ERR(inode);
 149         if (!IS_ERR(inode)) {
 150                 init_special_inode(inode, inode->i_mode, rdev);
 151                 mark_inode_dirty(inode);
 152                 err = nilfs_add_nondir(dentry, inode);
 153         }
 154         if (!err)
 155                 err = nilfs_transaction_commit(dir->i_sb);
 156         else
 157                 nilfs_transaction_abort(dir->i_sb);
 158
 159         return err;
 160 }
 161
 162 static int nilfs_symlink(struct inode *dir, struct dentry *dentry,
 163                          const char *symname)
 164 {
 165         struct nilfs_transaction_info ti;
 166         struct super_block *sb = dir->i_sb;
 167         unsigned l = strlen(symname)+1;
 168         struct inode *inode;
 169         int err;
 170
 171         if (l > sb->s_blocksize)
 172                 return -ENAMETOOLONG;
 173
 174         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 175         if (err)
 176                 return err;
 177
 178         inode = nilfs_new_inode(dir, S_IFLNK | S_IRWXUGO);
 179         err = PTR_ERR(inode);
 180         if (IS_ERR(inode))
 181                 goto out;
 182
 183         /* slow symlink */
 184         inode->i_op = &nilfs_symlink_inode_operations;
 185         inode->i_mapping->a_ops = &nilfs_aops;
 186         err = page_symlink(inode, symname, l);
 187         if (err)
 188                 goto out_fail;
 189
 190         /* mark_inode_dirty(inode); */
 191         /* nilfs_new_inode() and page_symlink() do this */
 192
 193         err = nilfs_add_nondir(dentry, inode);
 194 out:
 195         if (!err)
 196                 err = nilfs_transaction_commit(dir->i_sb);
 197         else
 198                 nilfs_transaction_abort(dir->i_sb);
 199
 200         return err;
 201
 202 out_fail:
 203         inode_dec_link_count(inode);
 204         iput(inode);
 205         goto out;
 206 }
 207
 208 static int nilfs_link(struct dentry *old_dentry, struct inode *dir,
 209                       struct dentry *dentry)
 210 {
 211         struct inode *inode = old_dentry->d_inode;
 212         struct nilfs_transaction_info ti;
 213         int err;
 214
 215         if (inode->i_nlink >= NILFS_LINK_MAX)
 216                 return -EMLINK;
 217
 218         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 219         if (err)
 220                 return err;
 221
 222         inode->i_ctime = CURRENT_TIME;
 223         inode_inc_link_count(inode);
 224         atomic_inc(&inode->i_count);
 225
 226         err = nilfs_add_nondir(dentry, inode);
 227         if (!err)
 228                 err = nilfs_transaction_commit(dir->i_sb);
 229         else
 230                 nilfs_transaction_abort(dir->i_sb);
 231
 232         return err;
 233 }
 234
 235 static int nilfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 236 {
 237         struct inode *inode;
 238         struct nilfs_transaction_info ti;
 239         int err;
 240
 241         if (dir->i_nlink >= NILFS_LINK_MAX)
 242                 return -EMLINK;
 243
 244         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 245         if (err)
 246                 return err;
 247
 248         inode_inc_link_count(dir);
 249
 250         inode = nilfs_new_inode(dir, S_IFDIR | mode);
 251         err = PTR_ERR(inode);
 252         if (IS_ERR(inode))
 253                 goto out_dir;
 254
 255         inode->i_op = &nilfs_dir_inode_operations;
 256         inode->i_fop = &nilfs_dir_operations;
 257         inode->i_mapping->a_ops = &nilfs_aops;
 258
 259         inode_inc_link_count(inode);
 260
 261         err = nilfs_make_empty(inode, dir);
 262         if (err)
 263                 goto out_fail;
 264
 265         err = nilfs_add_link(dentry, inode);
 266         if (err)
 267                 goto out_fail;
 268
 269         d_instantiate(dentry, inode);
 270 out:
 271         if (!err)
 272                 err = nilfs_transaction_commit(dir->i_sb);
 273         else
 274                 nilfs_transaction_abort(dir->i_sb);
 275
 276         return err;
 277
 278 out_fail:
 279         inode_dec_link_count(inode);
 280         inode_dec_link_count(inode);
 281         iput(inode);
 282 out_dir:
 283         inode_dec_link_count(dir);
 284         goto out;
 285 }
 286
 287 static int nilfs_unlink(struct inode *dir, struct dentry *dentry)
 288 {
 289         struct inode *inode;
 290         struct nilfs_dir_entry *de;
 291         struct page *page;
 292         struct nilfs_transaction_info ti;
 293         int err;
 294
 295         err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
 296         if (err)
 297                 return err;
 298
 299         err = -ENOENT;
 300         de = nilfs_find_entry(dir, dentry, &page);
 301         if (!de)
 302                 goto out;
 303
 304         inode = dentry->d_inode;
 305         err = -EIO;
 306         if (le64_to_cpu(de->inode) != inode->i_ino)
 307                 goto out;
 308
 309         if (!inode->i_nlink) {
 310                 nilfs_warning(inode->i_sb, __func__,
 311                               "deleting nonexistent file (%lu), %d\n",
 312                               inode->i_ino, inode->i_nlink);
 313                 inode->i_nlink = 1;
 314         }
 315         err = nilfs_delete_entry(de, page);
 316         if (err)
 317                 goto out;
 318
 319         inode->i_ctime = dir->i_ctime;
 320         inode_dec_link_count(inode);
 321         err = 0;
 322 out:
 323         if (!err)
 324                 err = nilfs_transaction_commit(dir->i_sb);
 325         else
 326                 nilfs_transaction_abort(dir->i_sb);
 327
 328         return err;
 329 }
 330
 331 static int nilfs_rmdir(struct inode *dir, struct dentry *dentry)
 332 {
 333         struct inode *inode = dentry->d_inode;
 334         struct nilfs_transaction_info ti;
 335         int err;
 336
 337         err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
 338         if (err)
 339                 return err;
 340
 341         err = -ENOTEMPTY;
 342         if (nilfs_empty_dir(inode)) {
 343                 err = nilfs_unlink(dir, dentry);
 344                 if (!err) {
 345                         inode->i_size = 0;
 346                         inode_dec_link_count(inode);
 347                         inode_dec_link_count(dir);
 348                 }
 349         }
 350         if (!err)
 351                 err = nilfs_transaction_commit(dir->i_sb);
 352         else
 353                 nilfs_transaction_abort(dir->i_sb);
 354
 355         return err;
 356 }
 357
 358 static int nilfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 359                         struct inode *new_dir,  struct dentry *new_dentry)
 360 {
 361         struct inode *old_inode = old_dentry->d_inode;
 362         struct inode *new_inode = new_dentry->d_inode;
 363         struct page *dir_page = NULL;
 364         struct nilfs_dir_entry *dir_de = NULL;
 365         struct page *old_page;
 366         struct nilfs_dir_entry *old_de;
 367         struct nilfs_transaction_info ti;
 368         int err;
 369
 370         err = nilfs_transaction_begin(old_dir->i_sb, &ti, 1);
 371         if (unlikely(err))
 372                 return err;
 373
 374         err = -ENOENT;
 375         old_de = nilfs_find_entry(old_dir, old_dentry, &old_page);
 376         if (!old_de)
 377                 goto out;
 378
 379         if (S_ISDIR(old_inode->i_mode)) {
 380                 err = -EIO;
 381                 dir_de = nilfs_dotdot(old_inode, &dir_page);
 382                 if (!dir_de)
 383                         goto out_old;
 384         }
 385
 386         if (new_inode) {
 387                 struct page *new_page;
 388                 struct nilfs_dir_entry *new_de;
 389
 390                 err = -ENOTEMPTY;
 391                 if (dir_de && !nilfs_empty_dir(new_inode))
 392                         goto out_dir;
 393
 394                 err = -ENOENT;
 395                 new_de = nilfs_find_entry(new_dir, new_dentry, &new_page);
 396                 if (!new_de)
 397                         goto out_dir;
 398                 inode_inc_link_count(old_inode);
 399                 nilfs_set_link(new_dir, new_de, new_page, old_inode);
 400                 new_inode->i_ctime = CURRENT_TIME;
 401                 if (dir_de)
 402                         drop_nlink(new_inode);
 403                 inode_dec_link_count(new_inode);
 404         } else {
 405                 if (dir_de) {
 406                         err = -EMLINK;
 407                         if (new_dir->i_nlink >= NILFS_LINK_MAX)
 408                                 goto out_dir;
 409                 }
 410                 inode_inc_link_count(old_inode);
 411                 err = nilfs_add_link(new_dentry, old_inode);
 412                 if (err) {
 413                         inode_dec_link_count(old_inode);
 414                         goto out_dir;
 415                 }
 416                 if (dir_de)
 417                         inode_inc_link_count(new_dir);
 418         }
 419
 420         /*
 421          * Like most other Unix systems, set the ctime for inodes on a
 422          * rename.
 423          * inode_dec_link_count() will mark the inode dirty.
 424          */
 425         old_inode->i_ctime = CURRENT_TIME;
 426
 427         nilfs_delete_entry(old_de, old_page);
 428         inode_dec_link_count(old_inode);
 429
 430         if (dir_de) {
 431                 nilfs_set_link(old_inode, dir_de, dir_page, new_dir);
 432                 inode_dec_link_count(old_dir);
 433         }
 434
 435         err = nilfs_transaction_commit(old_dir->i_sb);
 436         return err;
 437
 438 out_dir:
 439         if (dir_de) {
 440                 kunmap(dir_page);
 441                 page_cache_release(dir_page);
 442         }
 443 out_old:
 444         kunmap(old_page);
 445         page_cache_release(old_page);
 446 out:
 447         nilfs_transaction_abort(old_dir->i_sb);
 448         return err;
 449 }
 450
 451 struct inode_operations nilfs_dir_inode_operations = {
 452         .create         = nilfs_create,
 453         .lookup         = nilfs_lookup,
 454         .link           = nilfs_link,
 455         .unlink         = nilfs_unlink,
 456         .symlink        = nilfs_symlink,
 457         .mkdir          = nilfs_mkdir,
 458         .rmdir          = nilfs_rmdir,
 459         .mknod          = nilfs_mknod,
 460         .rename         = nilfs_rename,
 461         .setattr        = nilfs_setattr,
 462         .permission     = nilfs_permission,
 463 };
 464
 465 struct inode_operations nilfs_special_inode_operations = {
 466         .setattr        = nilfs_setattr,
 467         .permission     = nilfs_permission,
 468 };
 469
 470 struct inode_operations nilfs_symlink_inode_operations = {
 471         .readlink       = generic_readlink,
 472         .follow_link    = page_follow_link_light,
 473         .put_link       = page_put_link,
 474 };