fs/nilfs2/namei.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * NILFS pathname lookup operations.
   4  *
   5  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   6  *
   7  * Modified for NILFS by Amagai Yoshiji and Ryusuke Konishi.
   8  */
   9 /*
  10  *  linux/fs/ext2/namei.c
  11  *
  12  * Copyright (C) 1992, 1993, 1994, 1995
  13  * Remy Card (card@masi.ibp.fr)
  14  * Laboratoire MASI - Institut Blaise Pascal
  15  * Universite Pierre et Marie Curie (Paris VI)
  16  *
  17  *  from
  18  *
  19  *  linux/fs/minix/namei.c
  20  *
  21  *  Copyright (C) 1991, 1992  Linus Torvalds
  22  *
  23  *  Big-endian to little-endian byte-swapping/bitmaps by
  24  *        David S. Miller (davem@caip.rutgers.edu), 1995
  25  */
  26
  27 #include <linux/pagemap.h>
  28 #include "nilfs.h"
  29 #include "export.h"
  30
  31 #define NILFS_FID_SIZE_NON_CONNECTABLE \
  32         (offsetof(struct nilfs_fid, parent_gen) / 4)
  33 #define NILFS_FID_SIZE_CONNECTABLE      (sizeof(struct nilfs_fid) / 4)
  34
  35 static inline int nilfs_add_nondir(struct dentry *dentry, struct inode *inode)
  36 {
  37         int err = nilfs_add_link(dentry, inode);
  38
  39         if (!err) {
  40                 d_instantiate_new(dentry, inode);
  41                 return 0;
  42         }
  43         inode_dec_link_count(inode);
  44         unlock_new_inode(inode);
  45         iput(inode);
  46         return err;
  47 }
  48
  49 /*
  50  * Methods themselves.
  51  */
  52
  53 static struct dentry *
  54 nilfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
  55 {
  56         struct inode *inode;
  57         ino_t ino;
  58         int res;
  59
  60         if (dentry->d_name.len > NILFS_NAME_LEN)
  61                 return ERR_PTR(-ENAMETOOLONG);
  62
  63         res = nilfs_inode_by_name(dir, &dentry->d_name, &ino);
  64         if (res) {
  65                 if (res != -ENOENT)
  66                         return ERR_PTR(res);
  67                 inode = NULL;
  68         } else {
  69                 inode = nilfs_iget(dir->i_sb, NILFS_I(dir)->i_root, ino);
  70                 if (inode == ERR_PTR(-ESTALE)) {
  71                         nilfs_error(dir->i_sb,
  72                                         "deleted inode referenced: %lu", ino);
  73                         return ERR_PTR(-EIO);
  74                 }
  75         }
  76
  77         return d_splice_alias(inode, dentry);
  78 }
  79
  80 /*
  81  * By the time this is called, we already have created
  82  * the directory cache entry for the new file, but it
  83  * is so far negative - it has no inode.
  84  *
  85  * If the create succeeds, we fill in the inode information
  86  * with d_instantiate().
  87  */
  88 static int nilfs_create(struct mnt_idmap *idmap, struct inode *dir,
  89                         struct dentry *dentry, umode_t mode, bool excl)
  90 {
  91         struct inode *inode;
  92         struct nilfs_transaction_info ti;
  93         int err;
  94
  95         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
  96         if (err)
  97                 return err;
  98         inode = nilfs_new_inode(dir, mode);
  99         err = PTR_ERR(inode);
 100         if (!IS_ERR(inode)) {
 101                 inode->i_op = &nilfs_file_inode_operations;
 102                 inode->i_fop = &nilfs_file_operations;
 103                 inode->i_mapping->a_ops = &nilfs_aops;
 104                 nilfs_mark_inode_dirty(inode);
 105                 err = nilfs_add_nondir(dentry, inode);
 106         }
 107         if (!err)
 108                 err = nilfs_transaction_commit(dir->i_sb);
 109         else
 110                 nilfs_transaction_abort(dir->i_sb);
 111
 112         return err;
 113 }
 114
 115 static int
 116 nilfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
 117             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 mnt_idmap *idmap, struct inode *dir,
 142                          struct dentry *dentry, const char *symname)
 143 {
 144         struct nilfs_transaction_info ti;
 145         struct super_block *sb = dir->i_sb;
 146         unsigned int 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 | 0777);
 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         mapping_set_gfp_mask(inode->i_mapping,
 166                              mapping_gfp_constraint(inode->i_mapping,
 167                                                     ~__GFP_FS));
 168         inode->i_mapping->a_ops = &nilfs_aops;
 169         err = page_symlink(inode, symname, l);
 170         if (err)
 171                 goto out_fail;
 172
 173         /* mark_inode_dirty(inode); */
 174         /* page_symlink() do this */
 175
 176         err = nilfs_add_nondir(dentry, inode);
 177 out:
 178         if (!err)
 179                 err = nilfs_transaction_commit(dir->i_sb);
 180         else
 181                 nilfs_transaction_abort(dir->i_sb);
 182
 183         return err;
 184
 185 out_fail:
 186         drop_nlink(inode);
 187         nilfs_mark_inode_dirty(inode);
 188         unlock_new_inode(inode);
 189         iput(inode);
 190         goto out;
 191 }
 192
 193 static int nilfs_link(struct dentry *old_dentry, struct inode *dir,
 194                       struct dentry *dentry)
 195 {
 196         struct inode *inode = d_inode(old_dentry);
 197         struct nilfs_transaction_info ti;
 198         int err;
 199
 200         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 201         if (err)
 202                 return err;
 203
 204         inode_set_ctime_current(inode);
 205         inode_inc_link_count(inode);
 206         ihold(inode);
 207
 208         err = nilfs_add_link(dentry, inode);
 209         if (!err) {
 210                 d_instantiate(dentry, inode);
 211                 err = nilfs_transaction_commit(dir->i_sb);
 212         } else {
 213                 inode_dec_link_count(inode);
 214                 iput(inode);
 215                 nilfs_transaction_abort(dir->i_sb);
 216         }
 217
 218         return err;
 219 }
 220
 221 static int nilfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 222                        struct dentry *dentry, umode_t mode)
 223 {
 224         struct inode *inode;
 225         struct nilfs_transaction_info ti;
 226         int err;
 227
 228         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 229         if (err)
 230                 return err;
 231
 232         inc_nlink(dir);
 233
 234         inode = nilfs_new_inode(dir, S_IFDIR | mode);
 235         err = PTR_ERR(inode);
 236         if (IS_ERR(inode))
 237                 goto out_dir;
 238
 239         inode->i_op = &nilfs_dir_inode_operations;
 240         inode->i_fop = &nilfs_dir_operations;
 241         inode->i_mapping->a_ops = &nilfs_aops;
 242
 243         inc_nlink(inode);
 244
 245         err = nilfs_make_empty(inode, dir);
 246         if (err)
 247                 goto out_fail;
 248
 249         err = nilfs_add_link(dentry, inode);
 250         if (err)
 251                 goto out_fail;
 252
 253         nilfs_mark_inode_dirty(inode);
 254         d_instantiate_new(dentry, inode);
 255 out:
 256         if (!err)
 257                 err = nilfs_transaction_commit(dir->i_sb);
 258         else
 259                 nilfs_transaction_abort(dir->i_sb);
 260
 261         return err;
 262
 263 out_fail:
 264         drop_nlink(inode);
 265         drop_nlink(inode);
 266         nilfs_mark_inode_dirty(inode);
 267         unlock_new_inode(inode);
 268         iput(inode);
 269 out_dir:
 270         drop_nlink(dir);
 271         nilfs_mark_inode_dirty(dir);
 272         goto out;
 273 }
 274
 275 static int nilfs_do_unlink(struct inode *dir, struct dentry *dentry)
 276 {
 277         struct inode *inode;
 278         struct nilfs_dir_entry *de;
 279         struct folio *folio;
 280         int err;
 281
 282         de = nilfs_find_entry(dir, &dentry->d_name, &folio);
 283         if (IS_ERR(de)) {
 284                 err = PTR_ERR(de);
 285                 goto out;
 286         }
 287
 288         inode = d_inode(dentry);
 289         err = -EIO;
 290         if (le64_to_cpu(de->inode) != inode->i_ino)
 291                 goto out;
 292
 293         if (!inode->i_nlink) {
 294                 nilfs_warn(inode->i_sb,
 295                            "deleting nonexistent file (ino=%lu), %d",
 296                            inode->i_ino, inode->i_nlink);
 297                 set_nlink(inode, 1);
 298         }
 299         err = nilfs_delete_entry(de, folio);
 300         folio_release_kmap(folio, de);
 301         if (err)
 302                 goto out;
 303
 304         inode_set_ctime_to_ts(inode, inode_get_ctime(dir));
 305         drop_nlink(inode);
 306         err = 0;
 307 out:
 308         return err;
 309 }
 310
 311 static int nilfs_unlink(struct inode *dir, struct dentry *dentry)
 312 {
 313         struct nilfs_transaction_info ti;
 314         int err;
 315
 316         err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
 317         if (err)
 318                 return err;
 319
 320         err = nilfs_do_unlink(dir, dentry);
 321
 322         if (!err) {
 323                 nilfs_mark_inode_dirty(dir);
 324                 nilfs_mark_inode_dirty(d_inode(dentry));
 325                 err = nilfs_transaction_commit(dir->i_sb);
 326         } else
 327                 nilfs_transaction_abort(dir->i_sb);
 328
 329         return err;
 330 }
 331
 332 static int nilfs_rmdir(struct inode *dir, struct dentry *dentry)
 333 {
 334         struct inode *inode = d_inode(dentry);
 335         struct nilfs_transaction_info ti;
 336         int err;
 337
 338         err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
 339         if (err)
 340                 return err;
 341
 342         err = -ENOTEMPTY;
 343         if (nilfs_empty_dir(inode)) {
 344                 err = nilfs_do_unlink(dir, dentry);
 345                 if (!err) {
 346                         inode->i_size = 0;
 347                         drop_nlink(inode);
 348                         nilfs_mark_inode_dirty(inode);
 349                         drop_nlink(dir);
 350                         nilfs_mark_inode_dirty(dir);
 351                 }
 352         }
 353         if (!err)
 354                 err = nilfs_transaction_commit(dir->i_sb);
 355         else
 356                 nilfs_transaction_abort(dir->i_sb);
 357
 358         return err;
 359 }
 360
 361 static int nilfs_rename(struct mnt_idmap *idmap,
 362                         struct inode *old_dir, struct dentry *old_dentry,
 363                         struct inode *new_dir, struct dentry *new_dentry,
 364                         unsigned int flags)
 365 {
 366         struct inode *old_inode = d_inode(old_dentry);
 367         struct inode *new_inode = d_inode(new_dentry);
 368         struct folio *dir_folio = NULL;
 369         struct nilfs_dir_entry *dir_de = NULL;
 370         struct folio *old_folio;
 371         struct nilfs_dir_entry *old_de;
 372         struct nilfs_transaction_info ti;
 373         int err;
 374
 375         if (flags & ~RENAME_NOREPLACE)
 376                 return -EINVAL;
 377
 378         err = nilfs_transaction_begin(old_dir->i_sb, &ti, 1);
 379         if (unlikely(err))
 380                 return err;
 381
 382         old_de = nilfs_find_entry(old_dir, &old_dentry->d_name, &old_folio);
 383         if (IS_ERR(old_de)) {
 384                 err = PTR_ERR(old_de);
 385                 goto out;
 386         }
 387
 388         if (S_ISDIR(old_inode->i_mode)) {
 389                 err = -EIO;
 390                 dir_de = nilfs_dotdot(old_inode, &dir_folio);
 391                 if (!dir_de)
 392                         goto out_old;
 393         }
 394
 395         if (new_inode) {
 396                 struct folio *new_folio;
 397                 struct nilfs_dir_entry *new_de;
 398
 399                 err = -ENOTEMPTY;
 400                 if (dir_de && !nilfs_empty_dir(new_inode))
 401                         goto out_dir;
 402
 403                 new_de = nilfs_find_entry(new_dir, &new_dentry->d_name,
 404                                           &new_folio);
 405                 if (IS_ERR(new_de)) {
 406                         err = PTR_ERR(new_de);
 407                         goto out_dir;
 408                 }
 409                 nilfs_set_link(new_dir, new_de, new_folio, old_inode);
 410                 folio_release_kmap(new_folio, new_de);
 411                 nilfs_mark_inode_dirty(new_dir);
 412                 inode_set_ctime_current(new_inode);
 413                 if (dir_de)
 414                         drop_nlink(new_inode);
 415                 drop_nlink(new_inode);
 416                 nilfs_mark_inode_dirty(new_inode);
 417         } else {
 418                 err = nilfs_add_link(new_dentry, old_inode);
 419                 if (err)
 420                         goto out_dir;
 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         inode_set_ctime_current(old_inode);
 432
 433         nilfs_delete_entry(old_de, old_folio);
 434
 435         if (dir_de) {
 436                 nilfs_set_link(old_inode, dir_de, dir_folio, new_dir);
 437                 folio_release_kmap(dir_folio, dir_de);
 438                 drop_nlink(old_dir);
 439         }
 440         folio_release_kmap(old_folio, old_de);
 441
 442         nilfs_mark_inode_dirty(old_dir);
 443         nilfs_mark_inode_dirty(old_inode);
 444
 445         err = nilfs_transaction_commit(old_dir->i_sb);
 446         return err;
 447
 448 out_dir:
 449         if (dir_de)
 450                 folio_release_kmap(dir_folio, dir_de);
 451 out_old:
 452         folio_release_kmap(old_folio, old_de);
 453 out:
 454         nilfs_transaction_abort(old_dir->i_sb);
 455         return err;
 456 }
 457
 458 /*
 459  * Export operations
 460  */
 461 static struct dentry *nilfs_get_parent(struct dentry *child)
 462 {
 463         ino_t ino;
 464         int res;
 465         struct nilfs_root *root;
 466
 467         res = nilfs_inode_by_name(d_inode(child), &dotdot_name, &ino);
 468         if (res)
 469                 return ERR_PTR(res);
 470
 471         root = NILFS_I(d_inode(child))->i_root;
 472
 473         return d_obtain_alias(nilfs_iget(child->d_sb, root, ino));
 474 }
 475
 476 static struct dentry *nilfs_get_dentry(struct super_block *sb, u64 cno,
 477                                        u64 ino, u32 gen)
 478 {
 479         struct nilfs_root *root;
 480         struct inode *inode;
 481
 482         if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO)
 483                 return ERR_PTR(-ESTALE);
 484
 485         root = nilfs_lookup_root(sb->s_fs_info, cno);
 486         if (!root)
 487                 return ERR_PTR(-ESTALE);
 488
 489         inode = nilfs_iget(sb, root, ino);
 490         nilfs_put_root(root);
 491
 492         if (IS_ERR(inode))
 493                 return ERR_CAST(inode);
 494         if (gen && inode->i_generation != gen) {
 495                 iput(inode);
 496                 return ERR_PTR(-ESTALE);
 497         }
 498         return d_obtain_alias(inode);
 499 }
 500
 501 static struct dentry *nilfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
 502                                          int fh_len, int fh_type)
 503 {
 504         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 505
 506         if (fh_len < NILFS_FID_SIZE_NON_CONNECTABLE ||
 507             (fh_type != FILEID_NILFS_WITH_PARENT &&
 508              fh_type != FILEID_NILFS_WITHOUT_PARENT))
 509                 return NULL;
 510
 511         return nilfs_get_dentry(sb, fid->cno, fid->ino, fid->gen);
 512 }
 513
 514 static struct dentry *nilfs_fh_to_parent(struct super_block *sb, struct fid *fh,
 515                                          int fh_len, int fh_type)
 516 {
 517         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 518
 519         if (fh_len < NILFS_FID_SIZE_CONNECTABLE ||
 520             fh_type != FILEID_NILFS_WITH_PARENT)
 521                 return NULL;
 522
 523         return nilfs_get_dentry(sb, fid->cno, fid->parent_ino, fid->parent_gen);
 524 }
 525
 526 static int nilfs_encode_fh(struct inode *inode, __u32 *fh, int *lenp,
 527                            struct inode *parent)
 528 {
 529         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 530         struct nilfs_root *root = NILFS_I(inode)->i_root;
 531         int type;
 532
 533         if (parent && *lenp < NILFS_FID_SIZE_CONNECTABLE) {
 534                 *lenp = NILFS_FID_SIZE_CONNECTABLE;
 535                 return FILEID_INVALID;
 536         }
 537         if (*lenp < NILFS_FID_SIZE_NON_CONNECTABLE) {
 538                 *lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
 539                 return FILEID_INVALID;
 540         }
 541
 542         fid->cno = root->cno;
 543         fid->ino = inode->i_ino;
 544         fid->gen = inode->i_generation;
 545
 546         if (parent) {
 547                 fid->parent_ino = parent->i_ino;
 548                 fid->parent_gen = parent->i_generation;
 549                 type = FILEID_NILFS_WITH_PARENT;
 550                 *lenp = NILFS_FID_SIZE_CONNECTABLE;
 551         } else {
 552                 type = FILEID_NILFS_WITHOUT_PARENT;
 553                 *lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
 554         }
 555
 556         return type;
 557 }
 558
 559 const struct inode_operations nilfs_dir_inode_operations = {
 560         .create         = nilfs_create,
 561         .lookup         = nilfs_lookup,
 562         .link           = nilfs_link,
 563         .unlink         = nilfs_unlink,
 564         .symlink        = nilfs_symlink,
 565         .mkdir          = nilfs_mkdir,
 566         .rmdir          = nilfs_rmdir,
 567         .mknod          = nilfs_mknod,
 568         .rename         = nilfs_rename,
 569         .setattr        = nilfs_setattr,
 570         .permission     = nilfs_permission,
 571         .fiemap         = nilfs_fiemap,
 572         .fileattr_get   = nilfs_fileattr_get,
 573         .fileattr_set   = nilfs_fileattr_set,
 574 };
 575
 576 const struct inode_operations nilfs_special_inode_operations = {
 577         .setattr        = nilfs_setattr,
 578         .permission     = nilfs_permission,
 579 };
 580
 581 const struct inode_operations nilfs_symlink_inode_operations = {
 582         .get_link       = page_get_link,
 583         .permission     = nilfs_permission,
 584 };
 585
 586 const struct export_operations nilfs_export_ops = {
 587         .encode_fh = nilfs_encode_fh,
 588         .fh_to_dentry = nilfs_fh_to_dentry,
 589         .fh_to_parent = nilfs_fh_to_parent,
 590         .get_parent = nilfs_get_parent,
 591 };