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  * Modified for NILFS by Amagai Yoshiji and Ryusuke Konishi.
  17  */
  18 /*
  19  *  linux/fs/ext2/namei.c
  20  *
  21  * Copyright (C) 1992, 1993, 1994, 1995
  22  * Remy Card (card@masi.ibp.fr)
  23  * Laboratoire MASI - Institut Blaise Pascal
  24  * Universite Pierre et Marie Curie (Paris VI)
  25  *
  26  *  from
  27  *
  28  *  linux/fs/minix/namei.c
  29  *
  30  *  Copyright (C) 1991, 1992  Linus Torvalds
  31  *
  32  *  Big-endian to little-endian byte-swapping/bitmaps by
  33  *        David S. Miller (davem@caip.rutgers.edu), 1995
  34  */
  35
  36 #include <linux/pagemap.h>
  37 #include "nilfs.h"
  38 #include "export.h"
  39
  40 #define NILFS_FID_SIZE_NON_CONNECTABLE \
  41         (offsetof(struct nilfs_fid, parent_gen) / 4)
  42 #define NILFS_FID_SIZE_CONNECTABLE      (sizeof(struct nilfs_fid) / 4)
  43
  44 static inline int nilfs_add_nondir(struct dentry *dentry, struct inode *inode)
  45 {
  46         int err = nilfs_add_link(dentry, inode);
  47
  48         if (!err) {
  49                 d_instantiate(dentry, inode);
  50                 unlock_new_inode(inode);
  51                 return 0;
  52         }
  53         inode_dec_link_count(inode);
  54         unlock_new_inode(inode);
  55         iput(inode);
  56         return err;
  57 }
  58
  59 /*
  60  * Methods themselves.
  61  */
  62
  63 static struct dentry *
  64 nilfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
  65 {
  66         struct inode *inode;
  67         ino_t ino;
  68
  69         if (dentry->d_name.len > NILFS_NAME_LEN)
  70                 return ERR_PTR(-ENAMETOOLONG);
  71
  72         ino = nilfs_inode_by_name(dir, &dentry->d_name);
  73         inode = ino ? nilfs_iget(dir->i_sb, NILFS_I(dir)->i_root, ino) : NULL;
  74         return d_splice_alias(inode, dentry);
  75 }
  76
  77 /*
  78  * By the time this is called, we already have created
  79  * the directory cache entry for the new file, but it
  80  * is so far negative - it has no inode.
  81  *
  82  * If the create succeeds, we fill in the inode information
  83  * with d_instantiate().
  84  */
  85 static int nilfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
  86                         bool excl)
  87 {
  88         struct inode *inode;
  89         struct nilfs_transaction_info ti;
  90         int err;
  91
  92         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
  93         if (err)
  94                 return err;
  95         inode = nilfs_new_inode(dir, mode);
  96         err = PTR_ERR(inode);
  97         if (!IS_ERR(inode)) {
  98                 inode->i_op = &nilfs_file_inode_operations;
  99                 inode->i_fop = &nilfs_file_operations;
 100                 inode->i_mapping->a_ops = &nilfs_aops;
 101                 nilfs_mark_inode_dirty(inode);
 102                 err = nilfs_add_nondir(dentry, inode);
 103         }
 104         if (!err)
 105                 err = nilfs_transaction_commit(dir->i_sb);
 106         else
 107                 nilfs_transaction_abort(dir->i_sb);
 108
 109         return err;
 110 }
 111
 112 static int
 113 nilfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev)
 114 {
 115         struct inode *inode;
 116         struct nilfs_transaction_info ti;
 117         int err;
 118
 119         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 120         if (err)
 121                 return err;
 122         inode = nilfs_new_inode(dir, mode);
 123         err = PTR_ERR(inode);
 124         if (!IS_ERR(inode)) {
 125                 init_special_inode(inode, inode->i_mode, rdev);
 126                 nilfs_mark_inode_dirty(inode);
 127                 err = nilfs_add_nondir(dentry, inode);
 128         }
 129         if (!err)
 130                 err = nilfs_transaction_commit(dir->i_sb);
 131         else
 132                 nilfs_transaction_abort(dir->i_sb);
 133
 134         return err;
 135 }
 136
 137 static int nilfs_symlink(struct inode *dir, struct dentry *dentry,
 138                          const char *symname)
 139 {
 140         struct nilfs_transaction_info ti;
 141         struct super_block *sb = dir->i_sb;
 142         unsigned int l = strlen(symname) + 1;
 143         struct inode *inode;
 144         int err;
 145
 146         if (l > sb->s_blocksize)
 147                 return -ENAMETOOLONG;
 148
 149         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 150         if (err)
 151                 return err;
 152
 153         inode = nilfs_new_inode(dir, S_IFLNK | S_IRWXUGO);
 154         err = PTR_ERR(inode);
 155         if (IS_ERR(inode))
 156                 goto out;
 157
 158         /* slow symlink */
 159         inode->i_op = &nilfs_symlink_inode_operations;
 160         inode_nohighmem(inode);
 161         inode->i_mapping->a_ops = &nilfs_aops;
 162         err = page_symlink(inode, symname, l);
 163         if (err)
 164                 goto out_fail;
 165
 166         /* mark_inode_dirty(inode); */
 167         /* page_symlink() do this */
 168
 169         err = nilfs_add_nondir(dentry, inode);
 170 out:
 171         if (!err)
 172                 err = nilfs_transaction_commit(dir->i_sb);
 173         else
 174                 nilfs_transaction_abort(dir->i_sb);
 175
 176         return err;
 177
 178 out_fail:
 179         drop_nlink(inode);
 180         nilfs_mark_inode_dirty(inode);
 181         unlock_new_inode(inode);
 182         iput(inode);
 183         goto out;
 184 }
 185
 186 static int nilfs_link(struct dentry *old_dentry, struct inode *dir,
 187                       struct dentry *dentry)
 188 {
 189         struct inode *inode = d_inode(old_dentry);
 190         struct nilfs_transaction_info ti;
 191         int err;
 192
 193         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 194         if (err)
 195                 return err;
 196
 197         inode->i_ctime = CURRENT_TIME;
 198         inode_inc_link_count(inode);
 199         ihold(inode);
 200
 201         err = nilfs_add_link(dentry, inode);
 202         if (!err) {
 203                 d_instantiate(dentry, inode);
 204                 err = nilfs_transaction_commit(dir->i_sb);
 205         } else {
 206                 inode_dec_link_count(inode);
 207                 iput(inode);
 208                 nilfs_transaction_abort(dir->i_sb);
 209         }
 210
 211         return err;
 212 }
 213
 214 static int nilfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 215 {
 216         struct inode *inode;
 217         struct nilfs_transaction_info ti;
 218         int err;
 219
 220         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 221         if (err)
 222                 return err;
 223
 224         inc_nlink(dir);
 225
 226         inode = nilfs_new_inode(dir, S_IFDIR | mode);
 227         err = PTR_ERR(inode);
 228         if (IS_ERR(inode))
 229                 goto out_dir;
 230
 231         inode->i_op = &nilfs_dir_inode_operations;
 232         inode->i_fop = &nilfs_dir_operations;
 233         inode->i_mapping->a_ops = &nilfs_aops;
 234
 235         inc_nlink(inode);
 236
 237         err = nilfs_make_empty(inode, dir);
 238         if (err)
 239                 goto out_fail;
 240
 241         err = nilfs_add_link(dentry, inode);
 242         if (err)
 243                 goto out_fail;
 244
 245         nilfs_mark_inode_dirty(inode);
 246         d_instantiate(dentry, inode);
 247         unlock_new_inode(inode);
 248 out:
 249         if (!err)
 250                 err = nilfs_transaction_commit(dir->i_sb);
 251         else
 252                 nilfs_transaction_abort(dir->i_sb);
 253
 254         return err;
 255
 256 out_fail:
 257         drop_nlink(inode);
 258         drop_nlink(inode);
 259         nilfs_mark_inode_dirty(inode);
 260         unlock_new_inode(inode);
 261         iput(inode);
 262 out_dir:
 263         drop_nlink(dir);
 264         nilfs_mark_inode_dirty(dir);
 265         goto out;
 266 }
 267
 268 static int nilfs_do_unlink(struct inode *dir, struct dentry *dentry)
 269 {
 270         struct inode *inode;
 271         struct nilfs_dir_entry *de;
 272         struct page *page;
 273         int err;
 274
 275         err = -ENOENT;
 276         de = nilfs_find_entry(dir, &dentry->d_name, &page);
 277         if (!de)
 278                 goto out;
 279
 280         inode = d_inode(dentry);
 281         err = -EIO;
 282         if (le64_to_cpu(de->inode) != inode->i_ino)
 283                 goto out;
 284
 285         if (!inode->i_nlink) {
 286                 nilfs_msg(inode->i_sb, KERN_WARNING,
 287                           "deleting nonexistent file (ino=%lu), %d",
 288                           inode->i_ino, inode->i_nlink);
 289                 set_nlink(inode, 1);
 290         }
 291         err = nilfs_delete_entry(de, page);
 292         if (err)
 293                 goto out;
 294
 295         inode->i_ctime = dir->i_ctime;
 296         drop_nlink(inode);
 297         err = 0;
 298 out:
 299         return err;
 300 }
 301
 302 static int nilfs_unlink(struct inode *dir, struct dentry *dentry)
 303 {
 304         struct nilfs_transaction_info ti;
 305         int err;
 306
 307         err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
 308         if (err)
 309                 return err;
 310
 311         err = nilfs_do_unlink(dir, dentry);
 312
 313         if (!err) {
 314                 nilfs_mark_inode_dirty(dir);
 315                 nilfs_mark_inode_dirty(d_inode(dentry));
 316                 err = nilfs_transaction_commit(dir->i_sb);
 317         } else
 318                 nilfs_transaction_abort(dir->i_sb);
 319
 320         return err;
 321 }
 322
 323 static int nilfs_rmdir(struct inode *dir, struct dentry *dentry)
 324 {
 325         struct inode *inode = d_inode(dentry);
 326         struct nilfs_transaction_info ti;
 327         int err;
 328
 329         err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
 330         if (err)
 331                 return err;
 332
 333         err = -ENOTEMPTY;
 334         if (nilfs_empty_dir(inode)) {
 335                 err = nilfs_do_unlink(dir, dentry);
 336                 if (!err) {
 337                         inode->i_size = 0;
 338                         drop_nlink(inode);
 339                         nilfs_mark_inode_dirty(inode);
 340                         drop_nlink(dir);
 341                         nilfs_mark_inode_dirty(dir);
 342                 }
 343         }
 344         if (!err)
 345                 err = nilfs_transaction_commit(dir->i_sb);
 346         else
 347                 nilfs_transaction_abort(dir->i_sb);
 348
 349         return err;
 350 }
 351
 352 static int nilfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 353                         struct inode *new_dir,  struct dentry *new_dentry)
 354 {
 355         struct inode *old_inode = d_inode(old_dentry);
 356         struct inode *new_inode = d_inode(new_dentry);
 357         struct page *dir_page = NULL;
 358         struct nilfs_dir_entry *dir_de = NULL;
 359         struct page *old_page;
 360         struct nilfs_dir_entry *old_de;
 361         struct nilfs_transaction_info ti;
 362         int err;
 363
 364         err = nilfs_transaction_begin(old_dir->i_sb, &ti, 1);
 365         if (unlikely(err))
 366                 return err;
 367
 368         err = -ENOENT;
 369         old_de = nilfs_find_entry(old_dir, &old_dentry->d_name, &old_page);
 370         if (!old_de)
 371                 goto out;
 372
 373         if (S_ISDIR(old_inode->i_mode)) {
 374                 err = -EIO;
 375                 dir_de = nilfs_dotdot(old_inode, &dir_page);
 376                 if (!dir_de)
 377                         goto out_old;
 378         }
 379
 380         if (new_inode) {
 381                 struct page *new_page;
 382                 struct nilfs_dir_entry *new_de;
 383
 384                 err = -ENOTEMPTY;
 385                 if (dir_de && !nilfs_empty_dir(new_inode))
 386                         goto out_dir;
 387
 388                 err = -ENOENT;
 389                 new_de = nilfs_find_entry(new_dir, &new_dentry->d_name, &new_page);
 390                 if (!new_de)
 391                         goto out_dir;
 392                 nilfs_set_link(new_dir, new_de, new_page, old_inode);
 393                 nilfs_mark_inode_dirty(new_dir);
 394                 new_inode->i_ctime = CURRENT_TIME;
 395                 if (dir_de)
 396                         drop_nlink(new_inode);
 397                 drop_nlink(new_inode);
 398                 nilfs_mark_inode_dirty(new_inode);
 399         } else {
 400                 err = nilfs_add_link(new_dentry, old_inode);
 401                 if (err)
 402                         goto out_dir;
 403                 if (dir_de) {
 404                         inc_nlink(new_dir);
 405                         nilfs_mark_inode_dirty(new_dir);
 406                 }
 407         }
 408
 409         /*
 410          * Like most other Unix systems, set the ctime for inodes on a
 411          * rename.
 412          */
 413         old_inode->i_ctime = CURRENT_TIME;
 414
 415         nilfs_delete_entry(old_de, old_page);
 416
 417         if (dir_de) {
 418                 nilfs_set_link(old_inode, dir_de, dir_page, new_dir);
 419                 drop_nlink(old_dir);
 420         }
 421         nilfs_mark_inode_dirty(old_dir);
 422         nilfs_mark_inode_dirty(old_inode);
 423
 424         err = nilfs_transaction_commit(old_dir->i_sb);
 425         return err;
 426
 427 out_dir:
 428         if (dir_de) {
 429                 kunmap(dir_page);
 430                 put_page(dir_page);
 431         }
 432 out_old:
 433         kunmap(old_page);
 434         put_page(old_page);
 435 out:
 436         nilfs_transaction_abort(old_dir->i_sb);
 437         return err;
 438 }
 439
 440 /*
 441  * Export operations
 442  */
 443 static struct dentry *nilfs_get_parent(struct dentry *child)
 444 {
 445         unsigned long ino;
 446         struct inode *inode;
 447         struct qstr dotdot = QSTR_INIT("..", 2);
 448         struct nilfs_root *root;
 449
 450         ino = nilfs_inode_by_name(d_inode(child), &dotdot);
 451         if (!ino)
 452                 return ERR_PTR(-ENOENT);
 453
 454         root = NILFS_I(d_inode(child))->i_root;
 455
 456         inode = nilfs_iget(child->d_sb, root, ino);
 457         if (IS_ERR(inode))
 458                 return ERR_CAST(inode);
 459
 460         return d_obtain_alias(inode);
 461 }
 462
 463 static struct dentry *nilfs_get_dentry(struct super_block *sb, u64 cno,
 464                                        u64 ino, u32 gen)
 465 {
 466         struct nilfs_root *root;
 467         struct inode *inode;
 468
 469         if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO)
 470                 return ERR_PTR(-ESTALE);
 471
 472         root = nilfs_lookup_root(sb->s_fs_info, cno);
 473         if (!root)
 474                 return ERR_PTR(-ESTALE);
 475
 476         inode = nilfs_iget(sb, root, ino);
 477         nilfs_put_root(root);
 478
 479         if (IS_ERR(inode))
 480                 return ERR_CAST(inode);
 481         if (gen && inode->i_generation != gen) {
 482                 iput(inode);
 483                 return ERR_PTR(-ESTALE);
 484         }
 485         return d_obtain_alias(inode);
 486 }
 487
 488 static struct dentry *nilfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
 489                                          int fh_len, int fh_type)
 490 {
 491         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 492
 493         if (fh_len < NILFS_FID_SIZE_NON_CONNECTABLE ||
 494             (fh_type != FILEID_NILFS_WITH_PARENT &&
 495              fh_type != FILEID_NILFS_WITHOUT_PARENT))
 496                 return NULL;
 497
 498         return nilfs_get_dentry(sb, fid->cno, fid->ino, fid->gen);
 499 }
 500
 501 static struct dentry *nilfs_fh_to_parent(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_CONNECTABLE ||
 507             fh_type != FILEID_NILFS_WITH_PARENT)
 508                 return NULL;
 509
 510         return nilfs_get_dentry(sb, fid->cno, fid->parent_ino, fid->parent_gen);
 511 }
 512
 513 static int nilfs_encode_fh(struct inode *inode, __u32 *fh, int *lenp,
 514                            struct inode *parent)
 515 {
 516         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 517         struct nilfs_root *root = NILFS_I(inode)->i_root;
 518         int type;
 519
 520         if (parent && *lenp < NILFS_FID_SIZE_CONNECTABLE) {
 521                 *lenp = NILFS_FID_SIZE_CONNECTABLE;
 522                 return FILEID_INVALID;
 523         }
 524         if (*lenp < NILFS_FID_SIZE_NON_CONNECTABLE) {
 525                 *lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
 526                 return FILEID_INVALID;
 527         }
 528
 529         fid->cno = root->cno;
 530         fid->ino = inode->i_ino;
 531         fid->gen = inode->i_generation;
 532
 533         if (parent) {
 534                 fid->parent_ino = parent->i_ino;
 535                 fid->parent_gen = parent->i_generation;
 536                 type = FILEID_NILFS_WITH_PARENT;
 537                 *lenp = NILFS_FID_SIZE_CONNECTABLE;
 538         } else {
 539                 type = FILEID_NILFS_WITHOUT_PARENT;
 540                 *lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
 541         }
 542
 543         return type;
 544 }
 545
 546 const struct inode_operations nilfs_dir_inode_operations = {
 547         .create         = nilfs_create,
 548         .lookup         = nilfs_lookup,
 549         .link           = nilfs_link,
 550         .unlink         = nilfs_unlink,
 551         .symlink        = nilfs_symlink,
 552         .mkdir          = nilfs_mkdir,
 553         .rmdir          = nilfs_rmdir,
 554         .mknod          = nilfs_mknod,
 555         .rename         = nilfs_rename,
 556         .setattr        = nilfs_setattr,
 557         .permission     = nilfs_permission,
 558         .fiemap         = nilfs_fiemap,
 559 };
 560
 561 const struct inode_operations nilfs_special_inode_operations = {
 562         .setattr        = nilfs_setattr,
 563         .permission     = nilfs_permission,
 564 };
 565
 566 const struct inode_operations nilfs_symlink_inode_operations = {
 567         .readlink       = generic_readlink,
 568         .get_link       = page_get_link,
 569         .permission     = nilfs_permission,
 570 };
 571
 572 const struct export_operations nilfs_export_ops = {
 573         .encode_fh = nilfs_encode_fh,
 574         .fh_to_dentry = nilfs_fh_to_dentry,
 575         .fh_to_parent = nilfs_fh_to_parent,
 576         .get_parent = nilfs_get_parent,
 577 };