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         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 124         if (err)
 125                 return err;
 126         inode = nilfs_new_inode(dir, mode);
 127         err = PTR_ERR(inode);
 128         if (!IS_ERR(inode)) {
 129                 init_special_inode(inode, inode->i_mode, rdev);
 130                 nilfs_mark_inode_dirty(inode);
 131                 err = nilfs_add_nondir(dentry, inode);
 132         }
 133         if (!err)
 134                 err = nilfs_transaction_commit(dir->i_sb);
 135         else
 136                 nilfs_transaction_abort(dir->i_sb);
 137
 138         return err;
 139 }
 140
 141 static int nilfs_symlink(struct inode *dir, struct dentry *dentry,
 142                          const char *symname)
 143 {
 144         struct nilfs_transaction_info ti;
 145         struct super_block *sb = dir->i_sb;
 146         unsigned l = strlen(symname)+1;
 147         struct inode *inode;
 148         int err;
 149
 150         if (l > sb->s_blocksize)
 151                 return -ENAMETOOLONG;
 152
 153         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 154         if (err)
 155                 return err;
 156
 157         inode = nilfs_new_inode(dir, S_IFLNK | S_IRWXUGO);
 158         err = PTR_ERR(inode);
 159         if (IS_ERR(inode))
 160                 goto out;
 161
 162         /* slow symlink */
 163         inode->i_op = &nilfs_symlink_inode_operations;
 164         inode->i_mapping->a_ops = &nilfs_aops;
 165         err = page_symlink(inode, symname, l);
 166         if (err)
 167                 goto out_fail;
 168
 169         /* mark_inode_dirty(inode); */
 170         /* page_symlink() do this */
 171
 172         err = nilfs_add_nondir(dentry, inode);
 173 out:
 174         if (!err)
 175                 err = nilfs_transaction_commit(dir->i_sb);
 176         else
 177                 nilfs_transaction_abort(dir->i_sb);
 178
 179         return err;
 180
 181 out_fail:
 182         drop_nlink(inode);
 183         nilfs_mark_inode_dirty(inode);
 184         unlock_new_inode(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 = d_inode(old_dentry);
 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_link(dentry, inode);
 205         if (!err) {
 206                 d_instantiate(dentry, inode);
 207                 err = nilfs_transaction_commit(dir->i_sb);
 208         } else {
 209                 inode_dec_link_count(inode);
 210                 iput(inode);
 211                 nilfs_transaction_abort(dir->i_sb);
 212         }
 213
 214         return err;
 215 }
 216
 217 static int nilfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 218 {
 219         struct inode *inode;
 220         struct nilfs_transaction_info ti;
 221         int err;
 222
 223         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 224         if (err)
 225                 return err;
 226
 227         inc_nlink(dir);
 228
 229         inode = nilfs_new_inode(dir, S_IFDIR | mode);
 230         err = PTR_ERR(inode);
 231         if (IS_ERR(inode))
 232                 goto out_dir;
 233
 234         inode->i_op = &nilfs_dir_inode_operations;
 235         inode->i_fop = &nilfs_dir_operations;
 236         inode->i_mapping->a_ops = &nilfs_aops;
 237
 238         inc_nlink(inode);
 239
 240         err = nilfs_make_empty(inode, dir);
 241         if (err)
 242                 goto out_fail;
 243
 244         err = nilfs_add_link(dentry, inode);
 245         if (err)
 246                 goto out_fail;
 247
 248         nilfs_mark_inode_dirty(inode);
 249         d_instantiate(dentry, inode);
 250         unlock_new_inode(inode);
 251 out:
 252         if (!err)
 253                 err = nilfs_transaction_commit(dir->i_sb);
 254         else
 255                 nilfs_transaction_abort(dir->i_sb);
 256
 257         return err;
 258
 259 out_fail:
 260         drop_nlink(inode);
 261         drop_nlink(inode);
 262         nilfs_mark_inode_dirty(inode);
 263         unlock_new_inode(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 = d_inode(dentry);
 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                 set_nlink(inode, 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(d_inode(dentry));
 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 = d_inode(dentry);
 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 = d_inode(old_dentry);
 359         struct inode *new_inode = d_inode(new_dentry);
 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                 err = nilfs_add_link(new_dentry, old_inode);
 404                 if (err)
 405                         goto out_dir;
 406                 if (dir_de) {
 407                         inc_nlink(new_dir);
 408                         nilfs_mark_inode_dirty(new_dir);
 409                 }
 410         }
 411
 412         /*
 413          * Like most other Unix systems, set the ctime for inodes on a
 414          * rename.
 415          */
 416         old_inode->i_ctime = CURRENT_TIME;
 417
 418         nilfs_delete_entry(old_de, old_page);
 419
 420         if (dir_de) {
 421                 nilfs_set_link(old_inode, dir_de, dir_page, new_dir);
 422                 drop_nlink(old_dir);
 423         }
 424         nilfs_mark_inode_dirty(old_dir);
 425         nilfs_mark_inode_dirty(old_inode);
 426
 427         err = nilfs_transaction_commit(old_dir->i_sb);
 428         return err;
 429
 430 out_dir:
 431         if (dir_de) {
 432                 kunmap(dir_page);
 433                 page_cache_release(dir_page);
 434         }
 435 out_old:
 436         kunmap(old_page);
 437         page_cache_release(old_page);
 438 out:
 439         nilfs_transaction_abort(old_dir->i_sb);
 440         return err;
 441 }
 442
 443 /*
 444  * Export operations
 445  */
 446 static struct dentry *nilfs_get_parent(struct dentry *child)
 447 {
 448         unsigned long ino;
 449         struct inode *inode;
 450         struct qstr dotdot = QSTR_INIT("..", 2);
 451         struct nilfs_root *root;
 452
 453         ino = nilfs_inode_by_name(d_inode(child), &dotdot);
 454         if (!ino)
 455                 return ERR_PTR(-ENOENT);
 456
 457         root = NILFS_I(d_inode(child))->i_root;
 458
 459         inode = nilfs_iget(d_inode(child)->i_sb, root, ino);
 460         if (IS_ERR(inode))
 461                 return ERR_CAST(inode);
 462
 463         return d_obtain_alias(inode);
 464 }
 465
 466 static struct dentry *nilfs_get_dentry(struct super_block *sb, u64 cno,
 467                                        u64 ino, u32 gen)
 468 {
 469         struct nilfs_root *root;
 470         struct inode *inode;
 471
 472         if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO)
 473                 return ERR_PTR(-ESTALE);
 474
 475         root = nilfs_lookup_root(sb->s_fs_info, cno);
 476         if (!root)
 477                 return ERR_PTR(-ESTALE);
 478
 479         inode = nilfs_iget(sb, root, ino);
 480         nilfs_put_root(root);
 481
 482         if (IS_ERR(inode))
 483                 return ERR_CAST(inode);
 484         if (gen && inode->i_generation != gen) {
 485                 iput(inode);
 486                 return ERR_PTR(-ESTALE);
 487         }
 488         return d_obtain_alias(inode);
 489 }
 490
 491 static struct dentry *nilfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
 492                                          int fh_len, int fh_type)
 493 {
 494         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 495
 496         if (fh_len < NILFS_FID_SIZE_NON_CONNECTABLE ||
 497             (fh_type != FILEID_NILFS_WITH_PARENT &&
 498              fh_type != FILEID_NILFS_WITHOUT_PARENT))
 499                 return NULL;
 500
 501         return nilfs_get_dentry(sb, fid->cno, fid->ino, fid->gen);
 502 }
 503
 504 static struct dentry *nilfs_fh_to_parent(struct super_block *sb, struct fid *fh,
 505                                          int fh_len, int fh_type)
 506 {
 507         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 508
 509         if (fh_len < NILFS_FID_SIZE_CONNECTABLE ||
 510             fh_type != FILEID_NILFS_WITH_PARENT)
 511                 return NULL;
 512
 513         return nilfs_get_dentry(sb, fid->cno, fid->parent_ino, fid->parent_gen);
 514 }
 515
 516 static int nilfs_encode_fh(struct inode *inode, __u32 *fh, int *lenp,
 517                            struct inode *parent)
 518 {
 519         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 520         struct nilfs_root *root = NILFS_I(inode)->i_root;
 521         int type;
 522
 523         if (parent && *lenp < NILFS_FID_SIZE_CONNECTABLE) {
 524                 *lenp = NILFS_FID_SIZE_CONNECTABLE;
 525                 return FILEID_INVALID;
 526         }
 527         if (*lenp < NILFS_FID_SIZE_NON_CONNECTABLE) {
 528                 *lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
 529                 return FILEID_INVALID;
 530         }
 531
 532         fid->cno = root->cno;
 533         fid->ino = inode->i_ino;
 534         fid->gen = inode->i_generation;
 535
 536         if (parent) {
 537                 fid->parent_ino = parent->i_ino;
 538                 fid->parent_gen = parent->i_generation;
 539                 type = FILEID_NILFS_WITH_PARENT;
 540                 *lenp = NILFS_FID_SIZE_CONNECTABLE;
 541         } else {
 542                 type = FILEID_NILFS_WITHOUT_PARENT;
 543                 *lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
 544         }
 545
 546         return type;
 547 }
 548
 549 const struct inode_operations nilfs_dir_inode_operations = {
 550         .create         = nilfs_create,
 551         .lookup         = nilfs_lookup,
 552         .link           = nilfs_link,
 553         .unlink         = nilfs_unlink,
 554         .symlink        = nilfs_symlink,
 555         .mkdir          = nilfs_mkdir,
 556         .rmdir          = nilfs_rmdir,
 557         .mknod          = nilfs_mknod,
 558         .rename         = nilfs_rename,
 559         .setattr        = nilfs_setattr,
 560         .permission     = nilfs_permission,
 561         .fiemap         = nilfs_fiemap,
 562 };
 563
 564 const struct inode_operations nilfs_special_inode_operations = {
 565         .setattr        = nilfs_setattr,
 566         .permission     = nilfs_permission,
 567 };
 568
 569 const struct inode_operations nilfs_symlink_inode_operations = {
 570         .readlink       = generic_readlink,
 571         .follow_link    = page_follow_link_light,
 572         .put_link       = page_put_link,
 573         .permission     = nilfs_permission,
 574 };
 575
 576 const struct export_operations nilfs_export_ops = {
 577         .encode_fh = nilfs_encode_fh,
 578         .fh_to_dentry = nilfs_fh_to_dentry,
 579         .fh_to_parent = nilfs_fh_to_parent,
 580         .get_parent = nilfs_get_parent,
 581 };