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 = NULL;
  76         if (ino) {
  77                 inode = nilfs_iget(dir->i_sb, NILFS_I(dir)->i_root, ino);
  78                 if (IS_ERR(inode))
  79                         return ERR_CAST(inode);
  80         }
  81         return d_splice_alias(inode, dentry);
  82 }
  83
  84 /*
  85  * By the time this is called, we already have created
  86  * the directory cache entry for the new file, but it
  87  * is so far negative - it has no inode.
  88  *
  89  * If the create succeeds, we fill in the inode information
  90  * with d_instantiate().
  91  */
  92 static int nilfs_create(struct inode *dir, struct dentry *dentry, int mode,
  93                         struct nameidata *nd)
  94 {
  95         struct inode *inode;
  96         struct nilfs_transaction_info ti;
  97         int err;
  98
  99         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 100         if (err)
 101                 return err;
 102         inode = nilfs_new_inode(dir, mode);
 103         err = PTR_ERR(inode);
 104         if (!IS_ERR(inode)) {
 105                 inode->i_op = &nilfs_file_inode_operations;
 106                 inode->i_fop = &nilfs_file_operations;
 107                 inode->i_mapping->a_ops = &nilfs_aops;
 108                 nilfs_mark_inode_dirty(inode);
 109                 err = nilfs_add_nondir(dentry, inode);
 110         }
 111         if (!err)
 112                 err = nilfs_transaction_commit(dir->i_sb);
 113         else
 114                 nilfs_transaction_abort(dir->i_sb);
 115
 116         return err;
 117 }
 118
 119 static int
 120 nilfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
 121 {
 122         struct inode *inode;
 123         struct nilfs_transaction_info ti;
 124         int err;
 125
 126         if (!new_valid_dev(rdev))
 127                 return -EINVAL;
 128
 129         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 130         if (err)
 131                 return err;
 132         inode = nilfs_new_inode(dir, mode);
 133         err = PTR_ERR(inode);
 134         if (!IS_ERR(inode)) {
 135                 init_special_inode(inode, inode->i_mode, rdev);
 136                 nilfs_mark_inode_dirty(inode);
 137                 err = nilfs_add_nondir(dentry, inode);
 138         }
 139         if (!err)
 140                 err = nilfs_transaction_commit(dir->i_sb);
 141         else
 142                 nilfs_transaction_abort(dir->i_sb);
 143
 144         return err;
 145 }
 146
 147 static int nilfs_symlink(struct inode *dir, struct dentry *dentry,
 148                          const char *symname)
 149 {
 150         struct nilfs_transaction_info ti;
 151         struct super_block *sb = dir->i_sb;
 152         unsigned l = strlen(symname)+1;
 153         struct inode *inode;
 154         int err;
 155
 156         if (l > sb->s_blocksize)
 157                 return -ENAMETOOLONG;
 158
 159         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 160         if (err)
 161                 return err;
 162
 163         inode = nilfs_new_inode(dir, S_IFLNK | S_IRWXUGO);
 164         err = PTR_ERR(inode);
 165         if (IS_ERR(inode))
 166                 goto out;
 167
 168         /* slow symlink */
 169         inode->i_op = &nilfs_symlink_inode_operations;
 170         inode->i_mapping->a_ops = &nilfs_aops;
 171         err = page_symlink(inode, symname, l);
 172         if (err)
 173                 goto out_fail;
 174
 175         /* mark_inode_dirty(inode); */
 176         /* page_symlink() do this */
 177
 178         err = nilfs_add_nondir(dentry, inode);
 179 out:
 180         if (!err)
 181                 err = nilfs_transaction_commit(dir->i_sb);
 182         else
 183                 nilfs_transaction_abort(dir->i_sb);
 184
 185         return err;
 186
 187 out_fail:
 188         drop_nlink(inode);
 189         nilfs_mark_inode_dirty(inode);
 190         iput(inode);
 191         goto out;
 192 }
 193
 194 static int nilfs_link(struct dentry *old_dentry, struct inode *dir,
 195                       struct dentry *dentry)
 196 {
 197         struct inode *inode = old_dentry->d_inode;
 198         struct nilfs_transaction_info ti;
 199         int err;
 200
 201         if (inode->i_nlink >= NILFS_LINK_MAX)
 202                 return -EMLINK;
 203
 204         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 205         if (err)
 206                 return err;
 207
 208         inode->i_ctime = CURRENT_TIME;
 209         inode_inc_link_count(inode);
 210         atomic_inc(&inode->i_count);
 211
 212         err = nilfs_add_nondir(dentry, inode);
 213         if (!err)
 214                 err = nilfs_transaction_commit(dir->i_sb);
 215         else
 216                 nilfs_transaction_abort(dir->i_sb);
 217
 218         return err;
 219 }
 220
 221 static int nilfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 222 {
 223         struct inode *inode;
 224         struct nilfs_transaction_info ti;
 225         int err;
 226
 227         if (dir->i_nlink >= NILFS_LINK_MAX)
 228                 return -EMLINK;
 229
 230         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 231         if (err)
 232                 return err;
 233
 234         inc_nlink(dir);
 235
 236         inode = nilfs_new_inode(dir, S_IFDIR | mode);
 237         err = PTR_ERR(inode);
 238         if (IS_ERR(inode))
 239                 goto out_dir;
 240
 241         inode->i_op = &nilfs_dir_inode_operations;
 242         inode->i_fop = &nilfs_dir_operations;
 243         inode->i_mapping->a_ops = &nilfs_aops;
 244
 245         inc_nlink(inode);
 246
 247         err = nilfs_make_empty(inode, dir);
 248         if (err)
 249                 goto out_fail;
 250
 251         err = nilfs_add_link(dentry, inode);
 252         if (err)
 253                 goto out_fail;
 254
 255         nilfs_mark_inode_dirty(inode);
 256         d_instantiate(dentry, inode);
 257 out:
 258         if (!err)
 259                 err = nilfs_transaction_commit(dir->i_sb);
 260         else
 261                 nilfs_transaction_abort(dir->i_sb);
 262
 263         return err;
 264
 265 out_fail:
 266         drop_nlink(inode);
 267         drop_nlink(inode);
 268         nilfs_mark_inode_dirty(inode);
 269         iput(inode);
 270 out_dir:
 271         drop_nlink(dir);
 272         nilfs_mark_inode_dirty(dir);
 273         goto out;
 274 }
 275
 276 static int nilfs_do_unlink(struct inode *dir, struct dentry *dentry)
 277 {
 278         struct inode *inode;
 279         struct nilfs_dir_entry *de;
 280         struct page *page;
 281         int err;
 282
 283         err = -ENOENT;
 284         de = nilfs_find_entry(dir, &dentry->d_name, &page);
 285         if (!de)
 286                 goto out;
 287
 288         inode = dentry->d_inode;
 289         err = -EIO;
 290         if (le64_to_cpu(de->inode) != inode->i_ino)
 291                 goto out;
 292
 293         if (!inode->i_nlink) {
 294                 nilfs_warning(inode->i_sb, __func__,
 295                               "deleting nonexistent file (%lu), %d\n",
 296                               inode->i_ino, inode->i_nlink);
 297                 inode->i_nlink = 1;
 298         }
 299         err = nilfs_delete_entry(de, page);
 300         if (err)
 301                 goto out;
 302
 303         inode->i_ctime = dir->i_ctime;
 304         drop_nlink(inode);
 305         err = 0;
 306 out:
 307         return err;
 308 }
 309
 310 static int nilfs_unlink(struct inode *dir, struct dentry *dentry)
 311 {
 312         struct nilfs_transaction_info ti;
 313         int err;
 314
 315         err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
 316         if (err)
 317                 return err;
 318
 319         err = nilfs_do_unlink(dir, dentry);
 320
 321         if (!err) {
 322                 nilfs_mark_inode_dirty(dir);
 323                 nilfs_mark_inode_dirty(dentry->d_inode);
 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_do_unlink(dir, dentry);
 344                 if (!err) {
 345                         inode->i_size = 0;
 346                         drop_nlink(inode);
 347                         nilfs_mark_inode_dirty(inode);
 348                         drop_nlink(dir);
 349                         nilfs_mark_inode_dirty(dir);
 350                 }
 351         }
 352         if (!err)
 353                 err = nilfs_transaction_commit(dir->i_sb);
 354         else
 355                 nilfs_transaction_abort(dir->i_sb);
 356
 357         return err;
 358 }
 359
 360 static int nilfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 361                         struct inode *new_dir,  struct dentry *new_dentry)
 362 {
 363         struct inode *old_inode = old_dentry->d_inode;
 364         struct inode *new_inode = new_dentry->d_inode;
 365         struct page *dir_page = NULL;
 366         struct nilfs_dir_entry *dir_de = NULL;
 367         struct page *old_page;
 368         struct nilfs_dir_entry *old_de;
 369         struct nilfs_transaction_info ti;
 370         int err;
 371
 372         err = nilfs_transaction_begin(old_dir->i_sb, &ti, 1);
 373         if (unlikely(err))
 374                 return err;
 375
 376         err = -ENOENT;
 377         old_de = nilfs_find_entry(old_dir, &old_dentry->d_name, &old_page);
 378         if (!old_de)
 379                 goto out;
 380
 381         if (S_ISDIR(old_inode->i_mode)) {
 382                 err = -EIO;
 383                 dir_de = nilfs_dotdot(old_inode, &dir_page);
 384                 if (!dir_de)
 385                         goto out_old;
 386         }
 387
 388         if (new_inode) {
 389                 struct page *new_page;
 390                 struct nilfs_dir_entry *new_de;
 391
 392                 err = -ENOTEMPTY;
 393                 if (dir_de && !nilfs_empty_dir(new_inode))
 394                         goto out_dir;
 395
 396                 err = -ENOENT;
 397                 new_de = nilfs_find_entry(new_dir, &new_dentry->d_name, &new_page);
 398                 if (!new_de)
 399                         goto out_dir;
 400                 inc_nlink(old_inode);
 401                 nilfs_set_link(new_dir, new_de, new_page, old_inode);
 402                 nilfs_mark_inode_dirty(new_dir);
 403                 new_inode->i_ctime = CURRENT_TIME;
 404                 if (dir_de)
 405                         drop_nlink(new_inode);
 406                 drop_nlink(new_inode);
 407                 nilfs_mark_inode_dirty(new_inode);
 408         } else {
 409                 if (dir_de) {
 410                         err = -EMLINK;
 411                         if (new_dir->i_nlink >= NILFS_LINK_MAX)
 412                                 goto out_dir;
 413                 }
 414                 inc_nlink(old_inode);
 415                 err = nilfs_add_link(new_dentry, old_inode);
 416                 if (err) {
 417                         drop_nlink(old_inode);
 418                         nilfs_mark_inode_dirty(old_inode);
 419                         goto out_dir;
 420                 }
 421                 if (dir_de) {
 422                         inc_nlink(new_dir);
 423                         nilfs_mark_inode_dirty(new_dir);
 424                 }
 425         }
 426
 427         /*
 428          * Like most other Unix systems, set the ctime for inodes on a
 429          * rename.
 430          */
 431         old_inode->i_ctime = CURRENT_TIME;
 432
 433         nilfs_delete_entry(old_de, old_page);
 434         drop_nlink(old_inode);
 435
 436         if (dir_de) {
 437                 nilfs_set_link(old_inode, dir_de, dir_page, new_dir);
 438                 drop_nlink(old_dir);
 439         }
 440         nilfs_mark_inode_dirty(old_dir);
 441         nilfs_mark_inode_dirty(old_inode);
 442
 443         err = nilfs_transaction_commit(old_dir->i_sb);
 444         return err;
 445
 446 out_dir:
 447         if (dir_de) {
 448                 kunmap(dir_page);
 449                 page_cache_release(dir_page);
 450         }
 451 out_old:
 452         kunmap(old_page);
 453         page_cache_release(old_page);
 454 out:
 455         nilfs_transaction_abort(old_dir->i_sb);
 456         return err;
 457 }
 458
 459 /*
 460  * Export operations
 461  */
 462 static struct dentry *nilfs_get_parent(struct dentry *child)
 463 {
 464         unsigned long ino;
 465         struct inode *inode;
 466         struct qstr dotdot = {.name = "..", .len = 2};
 467         struct nilfs_root *root;
 468
 469         ino = nilfs_inode_by_name(child->d_inode, &dotdot);
 470         if (!ino)
 471                 return ERR_PTR(-ENOENT);
 472
 473         root = NILFS_I(child->d_inode)->i_root;
 474
 475         inode = nilfs_iget(child->d_inode->i_sb, root, ino);
 476         if (IS_ERR(inode))
 477                 return ERR_CAST(inode);
 478
 479         return d_obtain_alias(inode);
 480 }
 481
 482 static struct dentry *nilfs_get_dentry(struct super_block *sb, u64 cno,
 483                                        u64 ino, u32 gen)
 484 {
 485         struct nilfs_root *root;
 486         struct inode *inode;
 487
 488         if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO)
 489                 return ERR_PTR(-ESTALE);
 490
 491         root = nilfs_lookup_root(NILFS_SB(sb)->s_nilfs, cno);
 492         if (!root)
 493                 return ERR_PTR(-ESTALE);
 494
 495         inode = nilfs_iget(sb, root, ino);
 496         nilfs_put_root(root);
 497
 498         if (IS_ERR(inode))
 499                 return ERR_CAST(inode);
 500         if (gen && inode->i_generation != gen) {
 501                 iput(inode);
 502                 return ERR_PTR(-ESTALE);
 503         }
 504         return d_obtain_alias(inode);
 505 }
 506
 507 static struct dentry *nilfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
 508                                          int fh_len, int fh_type)
 509 {
 510         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 511
 512         if ((fh_len != NILFS_FID_SIZE_NON_CONNECTABLE &&
 513              fh_len != NILFS_FID_SIZE_CONNECTABLE) ||
 514             (fh_type != FILEID_NILFS_WITH_PARENT &&
 515              fh_type != FILEID_NILFS_WITHOUT_PARENT))
 516                 return NULL;
 517
 518         return nilfs_get_dentry(sb, fid->cno, fid->ino, fid->gen);
 519 }
 520
 521 static struct dentry *nilfs_fh_to_parent(struct super_block *sb, struct fid *fh,
 522                                          int fh_len, int fh_type)
 523 {
 524         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 525
 526         if (fh_len != NILFS_FID_SIZE_CONNECTABLE ||
 527             fh_type != FILEID_NILFS_WITH_PARENT)
 528                 return NULL;
 529
 530         return nilfs_get_dentry(sb, fid->cno, fid->parent_ino, fid->parent_gen);
 531 }
 532
 533 static int nilfs_encode_fh(struct dentry *dentry, __u32 *fh, int *lenp,
 534                            int connectable)
 535 {
 536         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 537         struct inode *inode = dentry->d_inode;
 538         struct nilfs_root *root = NILFS_I(inode)->i_root;
 539         int type;
 540
 541         if (*lenp < NILFS_FID_SIZE_NON_CONNECTABLE ||
 542             (connectable && *lenp < NILFS_FID_SIZE_CONNECTABLE))
 543                 return 255;
 544
 545         fid->cno = root->cno;
 546         fid->ino = inode->i_ino;
 547         fid->gen = inode->i_generation;
 548
 549         if (connectable && !S_ISDIR(inode->i_mode)) {
 550                 struct inode *parent;
 551
 552                 spin_lock(&dentry->d_lock);
 553                 parent = dentry->d_parent->d_inode;
 554                 fid->parent_ino = parent->i_ino;
 555                 fid->parent_gen = parent->i_generation;
 556                 spin_unlock(&dentry->d_lock);
 557
 558                 type = FILEID_NILFS_WITH_PARENT;
 559                 *lenp = NILFS_FID_SIZE_CONNECTABLE;
 560         } else {
 561                 type = FILEID_NILFS_WITHOUT_PARENT;
 562                 *lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
 563         }
 564
 565         return type;
 566 }
 567
 568 const struct inode_operations nilfs_dir_inode_operations = {
 569         .create         = nilfs_create,
 570         .lookup         = nilfs_lookup,
 571         .link           = nilfs_link,
 572         .unlink         = nilfs_unlink,
 573         .symlink        = nilfs_symlink,
 574         .mkdir          = nilfs_mkdir,
 575         .rmdir          = nilfs_rmdir,
 576         .mknod          = nilfs_mknod,
 577         .rename         = nilfs_rename,
 578         .setattr        = nilfs_setattr,
 579         .permission     = nilfs_permission,
 580 };
 581
 582 const struct inode_operations nilfs_special_inode_operations = {
 583         .setattr        = nilfs_setattr,
 584         .permission     = nilfs_permission,
 585 };
 586
 587 const struct inode_operations nilfs_symlink_inode_operations = {
 588         .readlink       = generic_readlink,
 589         .follow_link    = page_follow_link_light,
 590         .put_link       = page_put_link,
 591 };
 592
 593 const struct export_operations nilfs_export_ops = {
 594         .encode_fh = nilfs_encode_fh,
 595         .fh_to_dentry = nilfs_fh_to_dentry,
 596         .fh_to_parent = nilfs_fh_to_parent,
 597         .get_parent = nilfs_get_parent,
 598 };