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_nohighmem(inode);
 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         unlock_new_inode(inode);
 186         iput(inode);
 187         goto out;
 188 }
 189
 190 static int nilfs_link(struct dentry *old_dentry, struct inode *dir,
 191                       struct dentry *dentry)
 192 {
 193         struct inode *inode = d_inode(old_dentry);
 194         struct nilfs_transaction_info ti;
 195         int err;
 196
 197         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 198         if (err)
 199                 return err;
 200
 201         inode->i_ctime = CURRENT_TIME;
 202         inode_inc_link_count(inode);
 203         ihold(inode);
 204
 205         err = nilfs_add_link(dentry, inode);
 206         if (!err) {
 207                 d_instantiate(dentry, inode);
 208                 err = nilfs_transaction_commit(dir->i_sb);
 209         } else {
 210                 inode_dec_link_count(inode);
 211                 iput(inode);
 212                 nilfs_transaction_abort(dir->i_sb);
 213         }
 214
 215         return err;
 216 }
 217
 218 static int nilfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 219 {
 220         struct inode *inode;
 221         struct nilfs_transaction_info ti;
 222         int err;
 223
 224         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 225         if (err)
 226                 return err;
 227
 228         inc_nlink(dir);
 229
 230         inode = nilfs_new_inode(dir, S_IFDIR | mode);
 231         err = PTR_ERR(inode);
 232         if (IS_ERR(inode))
 233                 goto out_dir;
 234
 235         inode->i_op = &nilfs_dir_inode_operations;
 236         inode->i_fop = &nilfs_dir_operations;
 237         inode->i_mapping->a_ops = &nilfs_aops;
 238
 239         inc_nlink(inode);
 240
 241         err = nilfs_make_empty(inode, dir);
 242         if (err)
 243                 goto out_fail;
 244
 245         err = nilfs_add_link(dentry, inode);
 246         if (err)
 247                 goto out_fail;
 248
 249         nilfs_mark_inode_dirty(inode);
 250         d_instantiate(dentry, inode);
 251         unlock_new_inode(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         unlock_new_inode(inode);
 265         iput(inode);
 266 out_dir:
 267         drop_nlink(dir);
 268         nilfs_mark_inode_dirty(dir);
 269         goto out;
 270 }
 271
 272 static int nilfs_do_unlink(struct inode *dir, struct dentry *dentry)
 273 {
 274         struct inode *inode;
 275         struct nilfs_dir_entry *de;
 276         struct page *page;
 277         int err;
 278
 279         err = -ENOENT;
 280         de = nilfs_find_entry(dir, &dentry->d_name, &page);
 281         if (!de)
 282                 goto out;
 283
 284         inode = d_inode(dentry);
 285         err = -EIO;
 286         if (le64_to_cpu(de->inode) != inode->i_ino)
 287                 goto out;
 288
 289         if (!inode->i_nlink) {
 290                 nilfs_warning(inode->i_sb, __func__,
 291                               "deleting nonexistent file (%lu), %d\n",
 292                               inode->i_ino, inode->i_nlink);
 293                 set_nlink(inode, 1);
 294         }
 295         err = nilfs_delete_entry(de, page);
 296         if (err)
 297                 goto out;
 298
 299         inode->i_ctime = dir->i_ctime;
 300         drop_nlink(inode);
 301         err = 0;
 302 out:
 303         return err;
 304 }
 305
 306 static int nilfs_unlink(struct inode *dir, struct dentry *dentry)
 307 {
 308         struct nilfs_transaction_info ti;
 309         int err;
 310
 311         err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
 312         if (err)
 313                 return err;
 314
 315         err = nilfs_do_unlink(dir, dentry);
 316
 317         if (!err) {
 318                 nilfs_mark_inode_dirty(dir);
 319                 nilfs_mark_inode_dirty(d_inode(dentry));
 320                 err = nilfs_transaction_commit(dir->i_sb);
 321         } else
 322                 nilfs_transaction_abort(dir->i_sb);
 323
 324         return err;
 325 }
 326
 327 static int nilfs_rmdir(struct inode *dir, struct dentry *dentry)
 328 {
 329         struct inode *inode = d_inode(dentry);
 330         struct nilfs_transaction_info ti;
 331         int err;
 332
 333         err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
 334         if (err)
 335                 return err;
 336
 337         err = -ENOTEMPTY;
 338         if (nilfs_empty_dir(inode)) {
 339                 err = nilfs_do_unlink(dir, dentry);
 340                 if (!err) {
 341                         inode->i_size = 0;
 342                         drop_nlink(inode);
 343                         nilfs_mark_inode_dirty(inode);
 344                         drop_nlink(dir);
 345                         nilfs_mark_inode_dirty(dir);
 346                 }
 347         }
 348         if (!err)
 349                 err = nilfs_transaction_commit(dir->i_sb);
 350         else
 351                 nilfs_transaction_abort(dir->i_sb);
 352
 353         return err;
 354 }
 355
 356 static int nilfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 357                         struct inode *new_dir,  struct dentry *new_dentry)
 358 {
 359         struct inode *old_inode = d_inode(old_dentry);
 360         struct inode *new_inode = d_inode(new_dentry);
 361         struct page *dir_page = NULL;
 362         struct nilfs_dir_entry *dir_de = NULL;
 363         struct page *old_page;
 364         struct nilfs_dir_entry *old_de;
 365         struct nilfs_transaction_info ti;
 366         int err;
 367
 368         err = nilfs_transaction_begin(old_dir->i_sb, &ti, 1);
 369         if (unlikely(err))
 370                 return err;
 371
 372         err = -ENOENT;
 373         old_de = nilfs_find_entry(old_dir, &old_dentry->d_name, &old_page);
 374         if (!old_de)
 375                 goto out;
 376
 377         if (S_ISDIR(old_inode->i_mode)) {
 378                 err = -EIO;
 379                 dir_de = nilfs_dotdot(old_inode, &dir_page);
 380                 if (!dir_de)
 381                         goto out_old;
 382         }
 383
 384         if (new_inode) {
 385                 struct page *new_page;
 386                 struct nilfs_dir_entry *new_de;
 387
 388                 err = -ENOTEMPTY;
 389                 if (dir_de && !nilfs_empty_dir(new_inode))
 390                         goto out_dir;
 391
 392                 err = -ENOENT;
 393                 new_de = nilfs_find_entry(new_dir, &new_dentry->d_name, &new_page);
 394                 if (!new_de)
 395                         goto out_dir;
 396                 nilfs_set_link(new_dir, new_de, new_page, old_inode);
 397                 nilfs_mark_inode_dirty(new_dir);
 398                 new_inode->i_ctime = CURRENT_TIME;
 399                 if (dir_de)
 400                         drop_nlink(new_inode);
 401                 drop_nlink(new_inode);
 402                 nilfs_mark_inode_dirty(new_inode);
 403         } else {
 404                 err = nilfs_add_link(new_dentry, old_inode);
 405                 if (err)
 406                         goto out_dir;
 407                 if (dir_de) {
 408                         inc_nlink(new_dir);
 409                         nilfs_mark_inode_dirty(new_dir);
 410                 }
 411         }
 412
 413         /*
 414          * Like most other Unix systems, set the ctime for inodes on a
 415          * rename.
 416          */
 417         old_inode->i_ctime = CURRENT_TIME;
 418
 419         nilfs_delete_entry(old_de, old_page);
 420
 421         if (dir_de) {
 422                 nilfs_set_link(old_inode, dir_de, dir_page, new_dir);
 423                 drop_nlink(old_dir);
 424         }
 425         nilfs_mark_inode_dirty(old_dir);
 426         nilfs_mark_inode_dirty(old_inode);
 427
 428         err = nilfs_transaction_commit(old_dir->i_sb);
 429         return err;
 430
 431 out_dir:
 432         if (dir_de) {
 433                 kunmap(dir_page);
 434                 page_cache_release(dir_page);
 435         }
 436 out_old:
 437         kunmap(old_page);
 438         page_cache_release(old_page);
 439 out:
 440         nilfs_transaction_abort(old_dir->i_sb);
 441         return err;
 442 }
 443
 444 /*
 445  * Export operations
 446  */
 447 static struct dentry *nilfs_get_parent(struct dentry *child)
 448 {
 449         unsigned long ino;
 450         struct inode *inode;
 451         struct qstr dotdot = QSTR_INIT("..", 2);
 452         struct nilfs_root *root;
 453
 454         ino = nilfs_inode_by_name(d_inode(child), &dotdot);
 455         if (!ino)
 456                 return ERR_PTR(-ENOENT);
 457
 458         root = NILFS_I(d_inode(child))->i_root;
 459
 460         inode = nilfs_iget(d_inode(child)->i_sb, root, ino);
 461         if (IS_ERR(inode))
 462                 return ERR_CAST(inode);
 463
 464         return d_obtain_alias(inode);
 465 }
 466
 467 static struct dentry *nilfs_get_dentry(struct super_block *sb, u64 cno,
 468                                        u64 ino, u32 gen)
 469 {
 470         struct nilfs_root *root;
 471         struct inode *inode;
 472
 473         if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO)
 474                 return ERR_PTR(-ESTALE);
 475
 476         root = nilfs_lookup_root(sb->s_fs_info, cno);
 477         if (!root)
 478                 return ERR_PTR(-ESTALE);
 479
 480         inode = nilfs_iget(sb, root, ino);
 481         nilfs_put_root(root);
 482
 483         if (IS_ERR(inode))
 484                 return ERR_CAST(inode);
 485         if (gen && inode->i_generation != gen) {
 486                 iput(inode);
 487                 return ERR_PTR(-ESTALE);
 488         }
 489         return d_obtain_alias(inode);
 490 }
 491
 492 static struct dentry *nilfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
 493                                          int fh_len, int fh_type)
 494 {
 495         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 496
 497         if (fh_len < NILFS_FID_SIZE_NON_CONNECTABLE ||
 498             (fh_type != FILEID_NILFS_WITH_PARENT &&
 499              fh_type != FILEID_NILFS_WITHOUT_PARENT))
 500                 return NULL;
 501
 502         return nilfs_get_dentry(sb, fid->cno, fid->ino, fid->gen);
 503 }
 504
 505 static struct dentry *nilfs_fh_to_parent(struct super_block *sb, struct fid *fh,
 506                                          int fh_len, int fh_type)
 507 {
 508         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 509
 510         if (fh_len < NILFS_FID_SIZE_CONNECTABLE ||
 511             fh_type != FILEID_NILFS_WITH_PARENT)
 512                 return NULL;
 513
 514         return nilfs_get_dentry(sb, fid->cno, fid->parent_ino, fid->parent_gen);
 515 }
 516
 517 static int nilfs_encode_fh(struct inode *inode, __u32 *fh, int *lenp,
 518                            struct inode *parent)
 519 {
 520         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 521         struct nilfs_root *root = NILFS_I(inode)->i_root;
 522         int type;
 523
 524         if (parent && *lenp < NILFS_FID_SIZE_CONNECTABLE) {
 525                 *lenp = NILFS_FID_SIZE_CONNECTABLE;
 526                 return FILEID_INVALID;
 527         }
 528         if (*lenp < NILFS_FID_SIZE_NON_CONNECTABLE) {
 529                 *lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
 530                 return FILEID_INVALID;
 531         }
 532
 533         fid->cno = root->cno;
 534         fid->ino = inode->i_ino;
 535         fid->gen = inode->i_generation;
 536
 537         if (parent) {
 538                 fid->parent_ino = parent->i_ino;
 539                 fid->parent_gen = parent->i_generation;
 540                 type = FILEID_NILFS_WITH_PARENT;
 541                 *lenp = NILFS_FID_SIZE_CONNECTABLE;
 542         } else {
 543                 type = FILEID_NILFS_WITHOUT_PARENT;
 544                 *lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
 545         }
 546
 547         return type;
 548 }
 549
 550 const struct inode_operations nilfs_dir_inode_operations = {
 551         .create         = nilfs_create,
 552         .lookup         = nilfs_lookup,
 553         .link           = nilfs_link,
 554         .unlink         = nilfs_unlink,
 555         .symlink        = nilfs_symlink,
 556         .mkdir          = nilfs_mkdir,
 557         .rmdir          = nilfs_rmdir,
 558         .mknod          = nilfs_mknod,
 559         .rename         = nilfs_rename,
 560         .setattr        = nilfs_setattr,
 561         .permission     = nilfs_permission,
 562         .fiemap         = nilfs_fiemap,
 563 };
 564
 565 const struct inode_operations nilfs_special_inode_operations = {
 566         .setattr        = nilfs_setattr,
 567         .permission     = nilfs_permission,
 568 };
 569
 570 const struct inode_operations nilfs_symlink_inode_operations = {
 571         .readlink       = generic_readlink,
 572         .get_link       = page_get_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 };