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 #include "export.h"
  44
  45 #define NILFS_FID_SIZE_NON_CONNECTABLE \
  46         (offsetof(struct nilfs_fid, parent_gen) / 4)
  47 #define NILFS_FID_SIZE_CONNECTABLE      (sizeof(struct nilfs_fid) / 4)
  48
  49 static inline int nilfs_add_nondir(struct dentry *dentry, struct inode *inode)
  50 {
  51         int err = nilfs_add_link(dentry, inode);
  52         if (!err) {
  53                 d_instantiate(dentry, inode);
  54                 return 0;
  55         }
  56         inode_dec_link_count(inode);
  57         iput(inode);
  58         return err;
  59 }
  60
  61 /*
  62  * Methods themselves.
  63  */
  64
  65 static struct dentry *
  66 nilfs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
  67 {
  68         struct inode *inode;
  69         ino_t ino;
  70
  71         if (dentry->d_name.len > NILFS_NAME_LEN)
  72                 return ERR_PTR(-ENAMETOOLONG);
  73
  74         ino = nilfs_inode_by_name(dir, &dentry->d_name);
  75         inode = ino ? nilfs_iget(dir->i_sb, NILFS_I(dir)->i_root, ino) : NULL;
  76         return d_splice_alias(inode, dentry);
  77 }
  78
  79 /*
  80  * By the time this is called, we already have created
  81  * the directory cache entry for the new file, but it
  82  * is so far negative - it has no inode.
  83  *
  84  * If the create succeeds, we fill in the inode information
  85  * with d_instantiate().
  86  */
  87 static int nilfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
  88                         struct nameidata *nd)
  89 {
  90         struct inode *inode;
  91         struct nilfs_transaction_info ti;
  92         int err;
  93
  94         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
  95         if (err)
  96                 return err;
  97         inode = nilfs_new_inode(dir, mode);
  98         err = PTR_ERR(inode);
  99         if (!IS_ERR(inode)) {
 100                 inode->i_op = &nilfs_file_inode_operations;
 101                 inode->i_fop = &nilfs_file_operations;
 102                 inode->i_mapping->a_ops = &nilfs_aops;
 103                 nilfs_mark_inode_dirty(inode);
 104                 err = nilfs_add_nondir(dentry, inode);
 105         }
 106         if (!err)
 107                 err = nilfs_transaction_commit(dir->i_sb);
 108         else
 109                 nilfs_transaction_abort(dir->i_sb);
 110
 111         return err;
 112 }
 113
 114 static int
 115 nilfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev)
 116 {
 117         struct inode *inode;
 118         struct nilfs_transaction_info ti;
 119         int err;
 120
 121         if (!new_valid_dev(rdev))
 122                 return -EINVAL;
 123
 124         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 125         if (err)
 126                 return err;
 127         inode = nilfs_new_inode(dir, mode);
 128         err = PTR_ERR(inode);
 129         if (!IS_ERR(inode)) {
 130                 init_special_inode(inode, inode->i_mode, rdev);
 131                 nilfs_mark_inode_dirty(inode);
 132                 err = nilfs_add_nondir(dentry, inode);
 133         }
 134         if (!err)
 135                 err = nilfs_transaction_commit(dir->i_sb);
 136         else
 137                 nilfs_transaction_abort(dir->i_sb);
 138
 139         return err;
 140 }
 141
 142 static int nilfs_symlink(struct inode *dir, struct dentry *dentry,
 143                          const char *symname)
 144 {
 145         struct nilfs_transaction_info ti;
 146         struct super_block *sb = dir->i_sb;
 147         unsigned l = strlen(symname)+1;
 148         struct inode *inode;
 149         int err;
 150
 151         if (l > sb->s_blocksize)
 152                 return -ENAMETOOLONG;
 153
 154         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 155         if (err)
 156                 return err;
 157
 158         inode = nilfs_new_inode(dir, S_IFLNK | S_IRWXUGO);
 159         err = PTR_ERR(inode);
 160         if (IS_ERR(inode))
 161                 goto out;
 162
 163         /* slow symlink */
 164         inode->i_op = &nilfs_symlink_inode_operations;
 165         inode->i_mapping->a_ops = &nilfs_aops;
 166         err = page_symlink(inode, symname, l);
 167         if (err)
 168                 goto out_fail;
 169
 170         /* mark_inode_dirty(inode); */
 171         /* page_symlink() do this */
 172
 173         err = nilfs_add_nondir(dentry, inode);
 174 out:
 175         if (!err)
 176                 err = nilfs_transaction_commit(dir->i_sb);
 177         else
 178                 nilfs_transaction_abort(dir->i_sb);
 179
 180         return err;
 181
 182 out_fail:
 183         drop_nlink(inode);
 184         nilfs_mark_inode_dirty(inode);
 185         iput(inode);
 186         goto out;
 187 }
 188
 189 static int nilfs_link(struct dentry *old_dentry, struct inode *dir,
 190                       struct dentry *dentry)
 191 {
 192         struct inode *inode = old_dentry->d_inode;
 193         struct nilfs_transaction_info ti;
 194         int err;
 195
 196         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 197         if (err)
 198                 return err;
 199
 200         inode->i_ctime = CURRENT_TIME;
 201         inode_inc_link_count(inode);
 202         ihold(inode);
 203
 204         err = nilfs_add_nondir(dentry, inode);
 205         if (!err)
 206                 err = nilfs_transaction_commit(dir->i_sb);
 207         else
 208                 nilfs_transaction_abort(dir->i_sb);
 209
 210         return err;
 211 }
 212
 213 static int nilfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 214 {
 215         struct inode *inode;
 216         struct nilfs_transaction_info ti;
 217         int err;
 218
 219         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 220         if (err)
 221                 return err;
 222
 223         inc_nlink(dir);
 224
 225         inode = nilfs_new_inode(dir, S_IFDIR | mode);
 226         err = PTR_ERR(inode);
 227         if (IS_ERR(inode))
 228                 goto out_dir;
 229
 230         inode->i_op = &nilfs_dir_inode_operations;
 231         inode->i_fop = &nilfs_dir_operations;
 232         inode->i_mapping->a_ops = &nilfs_aops;
 233
 234         inc_nlink(inode);
 235
 236         err = nilfs_make_empty(inode, dir);
 237         if (err)
 238                 goto out_fail;
 239
 240         err = nilfs_add_link(dentry, inode);
 241         if (err)
 242                 goto out_fail;
 243
 244         nilfs_mark_inode_dirty(inode);
 245         d_instantiate(dentry, inode);
 246 out:
 247         if (!err)
 248                 err = nilfs_transaction_commit(dir->i_sb);
 249         else
 250                 nilfs_transaction_abort(dir->i_sb);
 251
 252         return err;
 253
 254 out_fail:
 255         drop_nlink(inode);
 256         drop_nlink(inode);
 257         nilfs_mark_inode_dirty(inode);
 258         iput(inode);
 259 out_dir:
 260         drop_nlink(dir);
 261         nilfs_mark_inode_dirty(dir);
 262         goto out;
 263 }
 264
 265 static int nilfs_do_unlink(struct inode *dir, struct dentry *dentry)
 266 {
 267         struct inode *inode;
 268         struct nilfs_dir_entry *de;
 269         struct page *page;
 270         int err;
 271
 272         err = -ENOENT;
 273         de = nilfs_find_entry(dir, &dentry->d_name, &page);
 274         if (!de)
 275                 goto out;
 276
 277         inode = dentry->d_inode;
 278         err = -EIO;
 279         if (le64_to_cpu(de->inode) != inode->i_ino)
 280                 goto out;
 281
 282         if (!inode->i_nlink) {
 283                 nilfs_warning(inode->i_sb, __func__,
 284                               "deleting nonexistent file (%lu), %d\n",
 285                               inode->i_ino, inode->i_nlink);
 286                 set_nlink(inode, 1);
 287         }
 288         err = nilfs_delete_entry(de, page);
 289         if (err)
 290                 goto out;
 291
 292         inode->i_ctime = dir->i_ctime;
 293         drop_nlink(inode);
 294         err = 0;
 295 out:
 296         return err;
 297 }
 298
 299 static int nilfs_unlink(struct inode *dir, struct dentry *dentry)
 300 {
 301         struct nilfs_transaction_info ti;
 302         int err;
 303
 304         err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
 305         if (err)
 306                 return err;
 307
 308         err = nilfs_do_unlink(dir, dentry);
 309
 310         if (!err) {
 311                 nilfs_mark_inode_dirty(dir);
 312                 nilfs_mark_inode_dirty(dentry->d_inode);
 313                 err = nilfs_transaction_commit(dir->i_sb);
 314         } else
 315                 nilfs_transaction_abort(dir->i_sb);
 316
 317         return err;
 318 }
 319
 320 static int nilfs_rmdir(struct inode *dir, struct dentry *dentry)
 321 {
 322         struct inode *inode = dentry->d_inode;
 323         struct nilfs_transaction_info ti;
 324         int err;
 325
 326         err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
 327         if (err)
 328                 return err;
 329
 330         err = -ENOTEMPTY;
 331         if (nilfs_empty_dir(inode)) {
 332                 err = nilfs_do_unlink(dir, dentry);
 333                 if (!err) {
 334                         inode->i_size = 0;
 335                         drop_nlink(inode);
 336                         nilfs_mark_inode_dirty(inode);
 337                         drop_nlink(dir);
 338                         nilfs_mark_inode_dirty(dir);
 339                 }
 340         }
 341         if (!err)
 342                 err = nilfs_transaction_commit(dir->i_sb);
 343         else
 344                 nilfs_transaction_abort(dir->i_sb);
 345
 346         return err;
 347 }
 348
 349 static int nilfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 350                         struct inode *new_dir,  struct dentry *new_dentry)
 351 {
 352         struct inode *old_inode = old_dentry->d_inode;
 353         struct inode *new_inode = new_dentry->d_inode;
 354         struct page *dir_page = NULL;
 355         struct nilfs_dir_entry *dir_de = NULL;
 356         struct page *old_page;
 357         struct nilfs_dir_entry *old_de;
 358         struct nilfs_transaction_info ti;
 359         int err;
 360
 361         err = nilfs_transaction_begin(old_dir->i_sb, &ti, 1);
 362         if (unlikely(err))
 363                 return err;
 364
 365         err = -ENOENT;
 366         old_de = nilfs_find_entry(old_dir, &old_dentry->d_name, &old_page);
 367         if (!old_de)
 368                 goto out;
 369
 370         if (S_ISDIR(old_inode->i_mode)) {
 371                 err = -EIO;
 372                 dir_de = nilfs_dotdot(old_inode, &dir_page);
 373                 if (!dir_de)
 374                         goto out_old;
 375         }
 376
 377         if (new_inode) {
 378                 struct page *new_page;
 379                 struct nilfs_dir_entry *new_de;
 380
 381                 err = -ENOTEMPTY;
 382                 if (dir_de && !nilfs_empty_dir(new_inode))
 383                         goto out_dir;
 384
 385                 err = -ENOENT;
 386                 new_de = nilfs_find_entry(new_dir, &new_dentry->d_name, &new_page);
 387                 if (!new_de)
 388                         goto out_dir;
 389                 nilfs_set_link(new_dir, new_de, new_page, old_inode);
 390                 nilfs_mark_inode_dirty(new_dir);
 391                 new_inode->i_ctime = CURRENT_TIME;
 392                 if (dir_de)
 393                         drop_nlink(new_inode);
 394                 drop_nlink(new_inode);
 395                 nilfs_mark_inode_dirty(new_inode);
 396         } else {
 397                 err = nilfs_add_link(new_dentry, old_inode);
 398                 if (err)
 399                         goto out_dir;
 400                 if (dir_de) {
 401                         inc_nlink(new_dir);
 402                         nilfs_mark_inode_dirty(new_dir);
 403                 }
 404         }
 405
 406         /*
 407          * Like most other Unix systems, set the ctime for inodes on a
 408          * rename.
 409          */
 410         old_inode->i_ctime = CURRENT_TIME;
 411
 412         nilfs_delete_entry(old_de, old_page);
 413
 414         if (dir_de) {
 415                 nilfs_set_link(old_inode, dir_de, dir_page, new_dir);
 416                 drop_nlink(old_dir);
 417         }
 418         nilfs_mark_inode_dirty(old_dir);
 419         nilfs_mark_inode_dirty(old_inode);
 420
 421         err = nilfs_transaction_commit(old_dir->i_sb);
 422         return err;
 423
 424 out_dir:
 425         if (dir_de) {
 426                 kunmap(dir_page);
 427                 page_cache_release(dir_page);
 428         }
 429 out_old:
 430         kunmap(old_page);
 431         page_cache_release(old_page);
 432 out:
 433         nilfs_transaction_abort(old_dir->i_sb);
 434         return err;
 435 }
 436
 437 /*
 438  * Export operations
 439  */
 440 static struct dentry *nilfs_get_parent(struct dentry *child)
 441 {
 442         unsigned long ino;
 443         struct inode *inode;
 444         struct qstr dotdot = {.name = "..", .len = 2};
 445         struct nilfs_root *root;
 446
 447         ino = nilfs_inode_by_name(child->d_inode, &dotdot);
 448         if (!ino)
 449                 return ERR_PTR(-ENOENT);
 450
 451         root = NILFS_I(child->d_inode)->i_root;
 452
 453         inode = nilfs_iget(child->d_inode->i_sb, root, ino);
 454         if (IS_ERR(inode))
 455                 return ERR_CAST(inode);
 456
 457         return d_obtain_alias(inode);
 458 }
 459
 460 static struct dentry *nilfs_get_dentry(struct super_block *sb, u64 cno,
 461                                        u64 ino, u32 gen)
 462 {
 463         struct nilfs_root *root;
 464         struct inode *inode;
 465
 466         if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO)
 467                 return ERR_PTR(-ESTALE);
 468
 469         root = nilfs_lookup_root(sb->s_fs_info, cno);
 470         if (!root)
 471                 return ERR_PTR(-ESTALE);
 472
 473         inode = nilfs_iget(sb, root, ino);
 474         nilfs_put_root(root);
 475
 476         if (IS_ERR(inode))
 477                 return ERR_CAST(inode);
 478         if (gen && inode->i_generation != gen) {
 479                 iput(inode);
 480                 return ERR_PTR(-ESTALE);
 481         }
 482         return d_obtain_alias(inode);
 483 }
 484
 485 static struct dentry *nilfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
 486                                          int fh_len, int fh_type)
 487 {
 488         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 489
 490         if ((fh_len != NILFS_FID_SIZE_NON_CONNECTABLE &&
 491              fh_len != NILFS_FID_SIZE_CONNECTABLE) ||
 492             (fh_type != FILEID_NILFS_WITH_PARENT &&
 493              fh_type != FILEID_NILFS_WITHOUT_PARENT))
 494                 return NULL;
 495
 496         return nilfs_get_dentry(sb, fid->cno, fid->ino, fid->gen);
 497 }
 498
 499 static struct dentry *nilfs_fh_to_parent(struct super_block *sb, struct fid *fh,
 500                                          int fh_len, int fh_type)
 501 {
 502         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 503
 504         if (fh_len != NILFS_FID_SIZE_CONNECTABLE ||
 505             fh_type != FILEID_NILFS_WITH_PARENT)
 506                 return NULL;
 507
 508         return nilfs_get_dentry(sb, fid->cno, fid->parent_ino, fid->parent_gen);
 509 }
 510
 511 static int nilfs_encode_fh(struct dentry *dentry, __u32 *fh, int *lenp,
 512                            int connectable)
 513 {
 514         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 515         struct inode *inode = dentry->d_inode;
 516         struct nilfs_root *root = NILFS_I(inode)->i_root;
 517         int type;
 518
 519         if (*lenp < NILFS_FID_SIZE_NON_CONNECTABLE ||
 520             (connectable && *lenp < NILFS_FID_SIZE_CONNECTABLE))
 521                 return 255;
 522
 523         fid->cno = root->cno;
 524         fid->ino = inode->i_ino;
 525         fid->gen = inode->i_generation;
 526
 527         if (connectable && !S_ISDIR(inode->i_mode)) {
 528                 struct inode *parent;
 529
 530                 spin_lock(&dentry->d_lock);
 531                 parent = dentry->d_parent->d_inode;
 532                 fid->parent_ino = parent->i_ino;
 533                 fid->parent_gen = parent->i_generation;
 534                 spin_unlock(&dentry->d_lock);
 535
 536                 type = FILEID_NILFS_WITH_PARENT;
 537                 *lenp = NILFS_FID_SIZE_CONNECTABLE;
 538         } else {
 539                 type = FILEID_NILFS_WITHOUT_PARENT;
 540                 *lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
 541         }
 542
 543         return type;
 544 }
 545
 546 const struct inode_operations nilfs_dir_inode_operations = {
 547         .create         = nilfs_create,
 548         .lookup         = nilfs_lookup,
 549         .link           = nilfs_link,
 550         .unlink         = nilfs_unlink,
 551         .symlink        = nilfs_symlink,
 552         .mkdir          = nilfs_mkdir,
 553         .rmdir          = nilfs_rmdir,
 554         .mknod          = nilfs_mknod,
 555         .rename         = nilfs_rename,
 556         .setattr        = nilfs_setattr,
 557         .permission     = nilfs_permission,
 558         .fiemap         = nilfs_fiemap,
 559 };
 560
 561 const struct inode_operations nilfs_special_inode_operations = {
 562         .setattr        = nilfs_setattr,
 563         .permission     = nilfs_permission,
 564 };
 565
 566 const struct inode_operations nilfs_symlink_inode_operations = {
 567         .readlink       = generic_readlink,
 568         .follow_link    = page_follow_link_light,
 569         .put_link       = page_put_link,
 570         .permission     = nilfs_permission,
 571 };
 572
 573 const struct export_operations nilfs_export_ops = {
 574         .encode_fh = nilfs_encode_fh,
 575         .fh_to_dentry = nilfs_fh_to_dentry,
 576         .fh_to_parent = nilfs_fh_to_parent,
 577         .get_parent = nilfs_get_parent,
 578 };