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, int 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, int 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         if (inode->i_nlink >= NILFS_LINK_MAX)
 197                 return -EMLINK;
 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_nondir(dentry, inode);
 208         if (!err)
 209                 err = nilfs_transaction_commit(dir->i_sb);
 210         else
 211                 nilfs_transaction_abort(dir->i_sb);
 212
 213         return err;
 214 }
 215
 216 static int nilfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 217 {
 218         struct inode *inode;
 219         struct nilfs_transaction_info ti;
 220         int err;
 221
 222         if (dir->i_nlink >= NILFS_LINK_MAX)
 223                 return -EMLINK;
 224
 225         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 226         if (err)
 227                 return err;
 228
 229         inc_nlink(dir);
 230
 231         inode = nilfs_new_inode(dir, S_IFDIR | mode);
 232         err = PTR_ERR(inode);
 233         if (IS_ERR(inode))
 234                 goto out_dir;
 235
 236         inode->i_op = &nilfs_dir_inode_operations;
 237         inode->i_fop = &nilfs_dir_operations;
 238         inode->i_mapping->a_ops = &nilfs_aops;
 239
 240         inc_nlink(inode);
 241
 242         err = nilfs_make_empty(inode, dir);
 243         if (err)
 244                 goto out_fail;
 245
 246         err = nilfs_add_link(dentry, inode);
 247         if (err)
 248                 goto out_fail;
 249
 250         nilfs_mark_inode_dirty(inode);
 251         d_instantiate(dentry, inode);
 252 out:
 253         if (!err)
 254                 err = nilfs_transaction_commit(dir->i_sb);
 255         else
 256                 nilfs_transaction_abort(dir->i_sb);
 257
 258         return err;
 259
 260 out_fail:
 261         drop_nlink(inode);
 262         drop_nlink(inode);
 263         nilfs_mark_inode_dirty(inode);
 264         iput(inode);
 265 out_dir:
 266         drop_nlink(dir);
 267         nilfs_mark_inode_dirty(dir);
 268         goto out;
 269 }
 270
 271 static int nilfs_do_unlink(struct inode *dir, struct dentry *dentry)
 272 {
 273         struct inode *inode;
 274         struct nilfs_dir_entry *de;
 275         struct page *page;
 276         int err;
 277
 278         err = -ENOENT;
 279         de = nilfs_find_entry(dir, &dentry->d_name, &page);
 280         if (!de)
 281                 goto out;
 282
 283         inode = dentry->d_inode;
 284         err = -EIO;
 285         if (le64_to_cpu(de->inode) != inode->i_ino)
 286                 goto out;
 287
 288         if (!inode->i_nlink) {
 289                 nilfs_warning(inode->i_sb, __func__,
 290                               "deleting nonexistent file (%lu), %d\n",
 291                               inode->i_ino, inode->i_nlink);
 292                 inode->i_nlink = 1;
 293         }
 294         err = nilfs_delete_entry(de, page);
 295         if (err)
 296                 goto out;
 297
 298         inode->i_ctime = dir->i_ctime;
 299         drop_nlink(inode);
 300         err = 0;
 301 out:
 302         return err;
 303 }
 304
 305 static int nilfs_unlink(struct inode *dir, struct dentry *dentry)
 306 {
 307         struct nilfs_transaction_info ti;
 308         int err;
 309
 310         err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
 311         if (err)
 312                 return err;
 313
 314         err = nilfs_do_unlink(dir, dentry);
 315
 316         if (!err) {
 317                 nilfs_mark_inode_dirty(dir);
 318                 nilfs_mark_inode_dirty(dentry->d_inode);
 319                 err = nilfs_transaction_commit(dir->i_sb);
 320         } else
 321                 nilfs_transaction_abort(dir->i_sb);
 322
 323         return err;
 324 }
 325
 326 static int nilfs_rmdir(struct inode *dir, struct dentry *dentry)
 327 {
 328         struct inode *inode = dentry->d_inode;
 329         struct nilfs_transaction_info ti;
 330         int err;
 331
 332         err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
 333         if (err)
 334                 return err;
 335
 336         err = -ENOTEMPTY;
 337         if (nilfs_empty_dir(inode)) {
 338                 err = nilfs_do_unlink(dir, dentry);
 339                 if (!err) {
 340                         inode->i_size = 0;
 341                         drop_nlink(inode);
 342                         nilfs_mark_inode_dirty(inode);
 343                         drop_nlink(dir);
 344                         nilfs_mark_inode_dirty(dir);
 345                 }
 346         }
 347         if (!err)
 348                 err = nilfs_transaction_commit(dir->i_sb);
 349         else
 350                 nilfs_transaction_abort(dir->i_sb);
 351
 352         return err;
 353 }
 354
 355 static int nilfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 356                         struct inode *new_dir,  struct dentry *new_dentry)
 357 {
 358         struct inode *old_inode = old_dentry->d_inode;
 359         struct inode *new_inode = new_dentry->d_inode;
 360         struct page *dir_page = NULL;
 361         struct nilfs_dir_entry *dir_de = NULL;
 362         struct page *old_page;
 363         struct nilfs_dir_entry *old_de;
 364         struct nilfs_transaction_info ti;
 365         int err;
 366
 367         err = nilfs_transaction_begin(old_dir->i_sb, &ti, 1);
 368         if (unlikely(err))
 369                 return err;
 370
 371         err = -ENOENT;
 372         old_de = nilfs_find_entry(old_dir, &old_dentry->d_name, &old_page);
 373         if (!old_de)
 374                 goto out;
 375
 376         if (S_ISDIR(old_inode->i_mode)) {
 377                 err = -EIO;
 378                 dir_de = nilfs_dotdot(old_inode, &dir_page);
 379                 if (!dir_de)
 380                         goto out_old;
 381         }
 382
 383         if (new_inode) {
 384                 struct page *new_page;
 385                 struct nilfs_dir_entry *new_de;
 386
 387                 err = -ENOTEMPTY;
 388                 if (dir_de && !nilfs_empty_dir(new_inode))
 389                         goto out_dir;
 390
 391                 err = -ENOENT;
 392                 new_de = nilfs_find_entry(new_dir, &new_dentry->d_name, &new_page);
 393                 if (!new_de)
 394                         goto out_dir;
 395                 nilfs_set_link(new_dir, new_de, new_page, old_inode);
 396                 nilfs_mark_inode_dirty(new_dir);
 397                 new_inode->i_ctime = CURRENT_TIME;
 398                 if (dir_de)
 399                         drop_nlink(new_inode);
 400                 drop_nlink(new_inode);
 401                 nilfs_mark_inode_dirty(new_inode);
 402         } else {
 403                 if (dir_de) {
 404                         err = -EMLINK;
 405                         if (new_dir->i_nlink >= NILFS_LINK_MAX)
 406                                 goto out_dir;
 407                 }
 408                 err = nilfs_add_link(new_dentry, old_inode);
 409                 if (err)
 410                         goto out_dir;
 411                 if (dir_de) {
 412                         inc_nlink(new_dir);
 413                         nilfs_mark_inode_dirty(new_dir);
 414                 }
 415         }
 416
 417         /*
 418          * Like most other Unix systems, set the ctime for inodes on a
 419          * rename.
 420          */
 421         old_inode->i_ctime = CURRENT_TIME;
 422
 423         nilfs_delete_entry(old_de, old_page);
 424
 425         if (dir_de) {
 426                 nilfs_set_link(old_inode, dir_de, dir_page, new_dir);
 427                 drop_nlink(old_dir);
 428         }
 429         nilfs_mark_inode_dirty(old_dir);
 430         nilfs_mark_inode_dirty(old_inode);
 431
 432         err = nilfs_transaction_commit(old_dir->i_sb);
 433         return err;
 434
 435 out_dir:
 436         if (dir_de) {
 437                 kunmap(dir_page);
 438                 page_cache_release(dir_page);
 439         }
 440 out_old:
 441         kunmap(old_page);
 442         page_cache_release(old_page);
 443 out:
 444         nilfs_transaction_abort(old_dir->i_sb);
 445         return err;
 446 }
 447
 448 /*
 449  * Export operations
 450  */
 451 static struct dentry *nilfs_get_parent(struct dentry *child)
 452 {
 453         unsigned long ino;
 454         struct inode *inode;
 455         struct qstr dotdot = {.name = "..", .len = 2};
 456         struct nilfs_root *root;
 457
 458         ino = nilfs_inode_by_name(child->d_inode, &dotdot);
 459         if (!ino)
 460                 return ERR_PTR(-ENOENT);
 461
 462         root = NILFS_I(child->d_inode)->i_root;
 463
 464         inode = nilfs_iget(child->d_inode->i_sb, root, ino);
 465         if (IS_ERR(inode))
 466                 return ERR_CAST(inode);
 467
 468         return d_obtain_alias(inode);
 469 }
 470
 471 static struct dentry *nilfs_get_dentry(struct super_block *sb, u64 cno,
 472                                        u64 ino, u32 gen)
 473 {
 474         struct nilfs_root *root;
 475         struct inode *inode;
 476
 477         if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO)
 478                 return ERR_PTR(-ESTALE);
 479
 480         root = nilfs_lookup_root(sb->s_fs_info, cno);
 481         if (!root)
 482                 return ERR_PTR(-ESTALE);
 483
 484         inode = nilfs_iget(sb, root, ino);
 485         nilfs_put_root(root);
 486
 487         if (IS_ERR(inode))
 488                 return ERR_CAST(inode);
 489         if (gen && inode->i_generation != gen) {
 490                 iput(inode);
 491                 return ERR_PTR(-ESTALE);
 492         }
 493         return d_obtain_alias(inode);
 494 }
 495
 496 static struct dentry *nilfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
 497                                          int fh_len, int fh_type)
 498 {
 499         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 500
 501         if ((fh_len != NILFS_FID_SIZE_NON_CONNECTABLE &&
 502              fh_len != NILFS_FID_SIZE_CONNECTABLE) ||
 503             (fh_type != FILEID_NILFS_WITH_PARENT &&
 504              fh_type != FILEID_NILFS_WITHOUT_PARENT))
 505                 return NULL;
 506
 507         return nilfs_get_dentry(sb, fid->cno, fid->ino, fid->gen);
 508 }
 509
 510 static struct dentry *nilfs_fh_to_parent(struct super_block *sb, struct fid *fh,
 511                                          int fh_len, int fh_type)
 512 {
 513         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 514
 515         if (fh_len != NILFS_FID_SIZE_CONNECTABLE ||
 516             fh_type != FILEID_NILFS_WITH_PARENT)
 517                 return NULL;
 518
 519         return nilfs_get_dentry(sb, fid->cno, fid->parent_ino, fid->parent_gen);
 520 }
 521
 522 static int nilfs_encode_fh(struct dentry *dentry, __u32 *fh, int *lenp,
 523                            int connectable)
 524 {
 525         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 526         struct inode *inode = dentry->d_inode;
 527         struct nilfs_root *root = NILFS_I(inode)->i_root;
 528         int type;
 529
 530         if (*lenp < NILFS_FID_SIZE_NON_CONNECTABLE ||
 531             (connectable && *lenp < NILFS_FID_SIZE_CONNECTABLE))
 532                 return 255;
 533
 534         fid->cno = root->cno;
 535         fid->ino = inode->i_ino;
 536         fid->gen = inode->i_generation;
 537
 538         if (connectable && !S_ISDIR(inode->i_mode)) {
 539                 struct inode *parent;
 540
 541                 spin_lock(&dentry->d_lock);
 542                 parent = dentry->d_parent->d_inode;
 543                 fid->parent_ino = parent->i_ino;
 544                 fid->parent_gen = parent->i_generation;
 545                 spin_unlock(&dentry->d_lock);
 546
 547                 type = FILEID_NILFS_WITH_PARENT;
 548                 *lenp = NILFS_FID_SIZE_CONNECTABLE;
 549         } else {
 550                 type = FILEID_NILFS_WITHOUT_PARENT;
 551                 *lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
 552         }
 553
 554         return type;
 555 }
 556
 557 const struct inode_operations nilfs_dir_inode_operations = {
 558         .create         = nilfs_create,
 559         .lookup         = nilfs_lookup,
 560         .link           = nilfs_link,
 561         .unlink         = nilfs_unlink,
 562         .symlink        = nilfs_symlink,
 563         .mkdir          = nilfs_mkdir,
 564         .rmdir          = nilfs_rmdir,
 565         .mknod          = nilfs_mknod,
 566         .rename         = nilfs_rename,
 567         .setattr        = nilfs_setattr,
 568         .permission     = nilfs_permission,
 569         .fiemap         = nilfs_fiemap,
 570 };
 571
 572 const struct inode_operations nilfs_special_inode_operations = {
 573         .setattr        = nilfs_setattr,
 574         .permission     = nilfs_permission,
 575 };
 576
 577 const struct inode_operations nilfs_symlink_inode_operations = {
 578         .readlink       = generic_readlink,
 579         .follow_link    = page_follow_link_light,
 580         .put_link       = page_put_link,
 581         .permission     = nilfs_permission,
 582 };
 583
 584 const struct export_operations nilfs_export_ops = {
 585         .encode_fh = nilfs_encode_fh,
 586         .fh_to_dentry = nilfs_fh_to_dentry,
 587         .fh_to_parent = nilfs_fh_to_parent,
 588         .get_parent = nilfs_get_parent,
 589 };