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                 unlock_new_inode(inode);
  55                 return 0;
  56         }
  57         inode_dec_link_count(inode);
  58         unlock_new_inode(inode);
  59         iput(inode);
  60         return err;
  61 }
  62
  63 /*
  64  * Methods themselves.
  65  */
  66
  67 static struct dentry *
  68 nilfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
  69 {
  70         struct inode *inode;
  71         ino_t ino;
  72
  73         if (dentry->d_name.len > NILFS_NAME_LEN)
  74                 return ERR_PTR(-ENAMETOOLONG);
  75
  76         ino = nilfs_inode_by_name(dir, &dentry->d_name);
  77         inode = ino ? nilfs_iget(dir->i_sb, NILFS_I(dir)->i_root, ino) : NULL;
  78         return d_splice_alias(inode, dentry);
  79 }
  80
  81 /*
  82  * By the time this is called, we already have created
  83  * the directory cache entry for the new file, but it
  84  * is so far negative - it has no inode.
  85  *
  86  * If the create succeeds, we fill in the inode information
  87  * with d_instantiate().
  88  */
  89 static int nilfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
  90                         bool excl)
  91 {
  92         struct inode *inode;
  93         struct nilfs_transaction_info ti;
  94         int err;
  95
  96         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
  97         if (err)
  98                 return err;
  99         inode = nilfs_new_inode(dir, mode);
 100         err = PTR_ERR(inode);
 101         if (!IS_ERR(inode)) {
 102                 inode->i_op = &nilfs_file_inode_operations;
 103                 inode->i_fop = &nilfs_file_operations;
 104                 inode->i_mapping->a_ops = &nilfs_aops;
 105                 nilfs_mark_inode_dirty(inode);
 106                 err = nilfs_add_nondir(dentry, inode);
 107         }
 108         if (!err)
 109                 err = nilfs_transaction_commit(dir->i_sb);
 110         else
 111                 nilfs_transaction_abort(dir->i_sb);
 112
 113         return err;
 114 }
 115
 116 static int
 117 nilfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev)
 118 {
 119         struct inode *inode;
 120         struct nilfs_transaction_info ti;
 121         int err;
 122
 123         if (!new_valid_dev(rdev))
 124                 return -EINVAL;
 125
 126         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 127         if (err)
 128                 return err;
 129         inode = nilfs_new_inode(dir, mode);
 130         err = PTR_ERR(inode);
 131         if (!IS_ERR(inode)) {
 132                 init_special_inode(inode, inode->i_mode, rdev);
 133                 nilfs_mark_inode_dirty(inode);
 134                 err = nilfs_add_nondir(dentry, inode);
 135         }
 136         if (!err)
 137                 err = nilfs_transaction_commit(dir->i_sb);
 138         else
 139                 nilfs_transaction_abort(dir->i_sb);
 140
 141         return err;
 142 }
 143
 144 static int nilfs_symlink(struct inode *dir, struct dentry *dentry,
 145                          const char *symname)
 146 {
 147         struct nilfs_transaction_info ti;
 148         struct super_block *sb = dir->i_sb;
 149         unsigned l = strlen(symname)+1;
 150         struct inode *inode;
 151         int err;
 152
 153         if (l > sb->s_blocksize)
 154                 return -ENAMETOOLONG;
 155
 156         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 157         if (err)
 158                 return err;
 159
 160         inode = nilfs_new_inode(dir, S_IFLNK | S_IRWXUGO);
 161         err = PTR_ERR(inode);
 162         if (IS_ERR(inode))
 163                 goto out;
 164
 165         /* slow symlink */
 166         inode->i_op = &nilfs_symlink_inode_operations;
 167         inode->i_mapping->a_ops = &nilfs_aops;
 168         err = page_symlink(inode, symname, l);
 169         if (err)
 170                 goto out_fail;
 171
 172         /* mark_inode_dirty(inode); */
 173         /* page_symlink() do this */
 174
 175         err = nilfs_add_nondir(dentry, inode);
 176 out:
 177         if (!err)
 178                 err = nilfs_transaction_commit(dir->i_sb);
 179         else
 180                 nilfs_transaction_abort(dir->i_sb);
 181
 182         return err;
 183
 184 out_fail:
 185         drop_nlink(inode);
 186         nilfs_mark_inode_dirty(inode);
 187         unlock_new_inode(inode);
 188         iput(inode);
 189         goto out;
 190 }
 191
 192 static int nilfs_link(struct dentry *old_dentry, struct inode *dir,
 193                       struct dentry *dentry)
 194 {
 195         struct inode *inode = old_dentry->d_inode;
 196         struct nilfs_transaction_info ti;
 197         int err;
 198
 199         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 200         if (err)
 201                 return err;
 202
 203         inode->i_ctime = CURRENT_TIME;
 204         inode_inc_link_count(inode);
 205         ihold(inode);
 206
 207         err = nilfs_add_link(dentry, inode);
 208         if (!err) {
 209                 d_instantiate(dentry, inode);
 210                 err = nilfs_transaction_commit(dir->i_sb);
 211         } else {
 212                 inode_dec_link_count(inode);
 213                 iput(inode);
 214                 nilfs_transaction_abort(dir->i_sb);
 215         }
 216
 217         return err;
 218 }
 219
 220 static int nilfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 221 {
 222         struct inode *inode;
 223         struct nilfs_transaction_info ti;
 224         int err;
 225
 226         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 227         if (err)
 228                 return err;
 229
 230         inc_nlink(dir);
 231
 232         inode = nilfs_new_inode(dir, S_IFDIR | mode);
 233         err = PTR_ERR(inode);
 234         if (IS_ERR(inode))
 235                 goto out_dir;
 236
 237         inode->i_op = &nilfs_dir_inode_operations;
 238         inode->i_fop = &nilfs_dir_operations;
 239         inode->i_mapping->a_ops = &nilfs_aops;
 240
 241         inc_nlink(inode);
 242
 243         err = nilfs_make_empty(inode, dir);
 244         if (err)
 245                 goto out_fail;
 246
 247         err = nilfs_add_link(dentry, inode);
 248         if (err)
 249                 goto out_fail;
 250
 251         nilfs_mark_inode_dirty(inode);
 252         d_instantiate(dentry, inode);
 253         unlock_new_inode(inode);
 254 out:
 255         if (!err)
 256                 err = nilfs_transaction_commit(dir->i_sb);
 257         else
 258                 nilfs_transaction_abort(dir->i_sb);
 259
 260         return err;
 261
 262 out_fail:
 263         drop_nlink(inode);
 264         drop_nlink(inode);
 265         nilfs_mark_inode_dirty(inode);
 266         unlock_new_inode(inode);
 267         iput(inode);
 268 out_dir:
 269         drop_nlink(dir);
 270         nilfs_mark_inode_dirty(dir);
 271         goto out;
 272 }
 273
 274 static int nilfs_do_unlink(struct inode *dir, struct dentry *dentry)
 275 {
 276         struct inode *inode;
 277         struct nilfs_dir_entry *de;
 278         struct page *page;
 279         int err;
 280
 281         err = -ENOENT;
 282         de = nilfs_find_entry(dir, &dentry->d_name, &page);
 283         if (!de)
 284                 goto out;
 285
 286         inode = dentry->d_inode;
 287         err = -EIO;
 288         if (le64_to_cpu(de->inode) != inode->i_ino)
 289                 goto out;
 290
 291         if (!inode->i_nlink) {
 292                 nilfs_warning(inode->i_sb, __func__,
 293                               "deleting nonexistent file (%lu), %d\n",
 294                               inode->i_ino, inode->i_nlink);
 295                 set_nlink(inode, 1);
 296         }
 297         err = nilfs_delete_entry(de, page);
 298         if (err)
 299                 goto out;
 300
 301         inode->i_ctime = dir->i_ctime;
 302         drop_nlink(inode);
 303         err = 0;
 304 out:
 305         return err;
 306 }
 307
 308 static int nilfs_unlink(struct inode *dir, struct dentry *dentry)
 309 {
 310         struct nilfs_transaction_info ti;
 311         int err;
 312
 313         err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
 314         if (err)
 315                 return err;
 316
 317         err = nilfs_do_unlink(dir, dentry);
 318
 319         if (!err) {
 320                 nilfs_mark_inode_dirty(dir);
 321                 nilfs_mark_inode_dirty(dentry->d_inode);
 322                 err = nilfs_transaction_commit(dir->i_sb);
 323         } else
 324                 nilfs_transaction_abort(dir->i_sb);
 325
 326         return err;
 327 }
 328
 329 static int nilfs_rmdir(struct inode *dir, struct dentry *dentry)
 330 {
 331         struct inode *inode = dentry->d_inode;
 332         struct nilfs_transaction_info ti;
 333         int err;
 334
 335         err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
 336         if (err)
 337                 return err;
 338
 339         err = -ENOTEMPTY;
 340         if (nilfs_empty_dir(inode)) {
 341                 err = nilfs_do_unlink(dir, dentry);
 342                 if (!err) {
 343                         inode->i_size = 0;
 344                         drop_nlink(inode);
 345                         nilfs_mark_inode_dirty(inode);
 346                         drop_nlink(dir);
 347                         nilfs_mark_inode_dirty(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->d_name, &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->d_name, &new_page);
 396                 if (!new_de)
 397                         goto out_dir;
 398                 nilfs_set_link(new_dir, new_de, new_page, old_inode);
 399                 nilfs_mark_inode_dirty(new_dir);
 400                 new_inode->i_ctime = CURRENT_TIME;
 401                 if (dir_de)
 402                         drop_nlink(new_inode);
 403                 drop_nlink(new_inode);
 404                 nilfs_mark_inode_dirty(new_inode);
 405         } else {
 406                 err = nilfs_add_link(new_dentry, old_inode);
 407                 if (err)
 408                         goto out_dir;
 409                 if (dir_de) {
 410                         inc_nlink(new_dir);
 411                         nilfs_mark_inode_dirty(new_dir);
 412                 }
 413         }
 414
 415         /*
 416          * Like most other Unix systems, set the ctime for inodes on a
 417          * rename.
 418          */
 419         old_inode->i_ctime = CURRENT_TIME;
 420
 421         nilfs_delete_entry(old_de, old_page);
 422
 423         if (dir_de) {
 424                 nilfs_set_link(old_inode, dir_de, dir_page, new_dir);
 425                 drop_nlink(old_dir);
 426         }
 427         nilfs_mark_inode_dirty(old_dir);
 428         nilfs_mark_inode_dirty(old_inode);
 429
 430         err = nilfs_transaction_commit(old_dir->i_sb);
 431         return err;
 432
 433 out_dir:
 434         if (dir_de) {
 435                 kunmap(dir_page);
 436                 page_cache_release(dir_page);
 437         }
 438 out_old:
 439         kunmap(old_page);
 440         page_cache_release(old_page);
 441 out:
 442         nilfs_transaction_abort(old_dir->i_sb);
 443         return err;
 444 }
 445
 446 /*
 447  * Export operations
 448  */
 449 static struct dentry *nilfs_get_parent(struct dentry *child)
 450 {
 451         unsigned long ino;
 452         struct inode *inode;
 453         struct qstr dotdot = QSTR_INIT("..", 2);
 454         struct nilfs_root *root;
 455
 456         ino = nilfs_inode_by_name(child->d_inode, &dotdot);
 457         if (!ino)
 458                 return ERR_PTR(-ENOENT);
 459
 460         root = NILFS_I(child->d_inode)->i_root;
 461
 462         inode = nilfs_iget(child->d_inode->i_sb, root, ino);
 463         if (IS_ERR(inode))
 464                 return ERR_CAST(inode);
 465
 466         return d_obtain_alias(inode);
 467 }
 468
 469 static struct dentry *nilfs_get_dentry(struct super_block *sb, u64 cno,
 470                                        u64 ino, u32 gen)
 471 {
 472         struct nilfs_root *root;
 473         struct inode *inode;
 474
 475         if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO)
 476                 return ERR_PTR(-ESTALE);
 477
 478         root = nilfs_lookup_root(sb->s_fs_info, cno);
 479         if (!root)
 480                 return ERR_PTR(-ESTALE);
 481
 482         inode = nilfs_iget(sb, root, ino);
 483         nilfs_put_root(root);
 484
 485         if (IS_ERR(inode))
 486                 return ERR_CAST(inode);
 487         if (gen && inode->i_generation != gen) {
 488                 iput(inode);
 489                 return ERR_PTR(-ESTALE);
 490         }
 491         return d_obtain_alias(inode);
 492 }
 493
 494 static struct dentry *nilfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
 495                                          int fh_len, int fh_type)
 496 {
 497         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 498
 499         if ((fh_len != NILFS_FID_SIZE_NON_CONNECTABLE &&
 500              fh_len != NILFS_FID_SIZE_CONNECTABLE) ||
 501             (fh_type != FILEID_NILFS_WITH_PARENT &&
 502              fh_type != FILEID_NILFS_WITHOUT_PARENT))
 503                 return NULL;
 504
 505         return nilfs_get_dentry(sb, fid->cno, fid->ino, fid->gen);
 506 }
 507
 508 static struct dentry *nilfs_fh_to_parent(struct super_block *sb, struct fid *fh,
 509                                          int fh_len, int fh_type)
 510 {
 511         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 512
 513         if (fh_len != NILFS_FID_SIZE_CONNECTABLE ||
 514             fh_type != FILEID_NILFS_WITH_PARENT)
 515                 return NULL;
 516
 517         return nilfs_get_dentry(sb, fid->cno, fid->parent_ino, fid->parent_gen);
 518 }
 519
 520 static int nilfs_encode_fh(struct inode *inode, __u32 *fh, int *lenp,
 521                            struct inode *parent)
 522 {
 523         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 524         struct nilfs_root *root = NILFS_I(inode)->i_root;
 525         int type;
 526
 527         if (parent && *lenp < NILFS_FID_SIZE_CONNECTABLE) {
 528                 *lenp = NILFS_FID_SIZE_CONNECTABLE;
 529                 return FILEID_INVALID;
 530         }
 531         if (*lenp < NILFS_FID_SIZE_NON_CONNECTABLE) {
 532                 *lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
 533                 return FILEID_INVALID;
 534         }
 535
 536         fid->cno = root->cno;
 537         fid->ino = inode->i_ino;
 538         fid->gen = inode->i_generation;
 539
 540         if (parent) {
 541                 fid->parent_ino = parent->i_ino;
 542                 fid->parent_gen = parent->i_generation;
 543                 type = FILEID_NILFS_WITH_PARENT;
 544                 *lenp = NILFS_FID_SIZE_CONNECTABLE;
 545         } else {
 546                 type = FILEID_NILFS_WITHOUT_PARENT;
 547                 *lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
 548         }
 549
 550         return type;
 551 }
 552
 553 const struct inode_operations nilfs_dir_inode_operations = {
 554         .create         = nilfs_create,
 555         .lookup         = nilfs_lookup,
 556         .link           = nilfs_link,
 557         .unlink         = nilfs_unlink,
 558         .symlink        = nilfs_symlink,
 559         .mkdir          = nilfs_mkdir,
 560         .rmdir          = nilfs_rmdir,
 561         .mknod          = nilfs_mknod,
 562         .rename         = nilfs_rename,
 563         .setattr        = nilfs_setattr,
 564         .permission     = nilfs_permission,
 565         .fiemap         = nilfs_fiemap,
 566 };
 567
 568 const struct inode_operations nilfs_special_inode_operations = {
 569         .setattr        = nilfs_setattr,
 570         .permission     = nilfs_permission,
 571 };
 572
 573 const struct inode_operations nilfs_symlink_inode_operations = {
 574         .readlink       = generic_readlink,
 575         .follow_link    = page_follow_link_light,
 576         .put_link       = page_put_link,
 577         .permission     = nilfs_permission,
 578 };
 579
 580 const struct export_operations nilfs_export_ops = {
 581         .encode_fh = nilfs_encode_fh,
 582         .fh_to_dentry = nilfs_fh_to_dentry,
 583         .fh_to_parent = nilfs_fh_to_parent,
 584         .get_parent = nilfs_get_parent,
 585 };