fs/ubifs/dir.c

   1 /* * This file is part of UBIFS.
   2  *
   3  * Copyright (C) 2006-2008 Nokia Corporation.
   4  * Copyright (C) 2006, 2007 University of Szeged, Hungary
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 as published by
   8  * the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program; if not, write to the Free Software Foundation, Inc., 51
  17  * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  18  *
  19  * Authors: Artem Bityutskiy (Битюцкий Артём)
  20  *          Adrian Hunter
  21  *          Zoltan Sogor
  22  */
  23
  24 /*
  25  * This file implements directory operations.
  26  *
  27  * All FS operations in this file allocate budget before writing anything to the
  28  * media. If they fail to allocate it, the error is returned. The only
  29  * exceptions are 'ubifs_unlink()' and 'ubifs_rmdir()' which keep working even
  30  * if they unable to allocate the budget, because deletion %-ENOSPC failure is
  31  * not what users are usually ready to get. UBIFS budgeting subsystem has some
  32  * space reserved for these purposes.
  33  *
  34  * All operations in this file write all inodes which they change straight
  35  * away, instead of marking them dirty. For example, 'ubifs_link()' changes
  36  * @i_size of the parent inode and writes the parent inode together with the
  37  * target inode. This was done to simplify file-system recovery which would
  38  * otherwise be very difficult to do. The only exception is rename which marks
  39  * the re-named inode dirty (because its @i_ctime is updated) but does not
  40  * write it, but just marks it as dirty.
  41  */
  42
  43 #include "ubifs.h"
  44
  45 /**
  46  * inherit_flags - inherit flags of the parent inode.
  47  * @dir: parent inode
  48  * @mode: new inode mode flags
  49  *
  50  * This is a helper function for 'ubifs_new_inode()' which inherits flag of the
  51  * parent directory inode @dir. UBIFS inodes inherit the following flags:
  52  * o %UBIFS_COMPR_FL, which is useful to switch compression on/of on
  53  *   sub-directory basis;
  54  * o %UBIFS_SYNC_FL - useful for the same reasons;
  55  * o %UBIFS_DIRSYNC_FL - similar, but relevant only to directories.
  56  *
  57  * This function returns the inherited flags.
  58  */
  59 static int inherit_flags(const struct inode *dir, int mode)
  60 {
  61         int flags;
  62         const struct ubifs_inode *ui = ubifs_inode(dir);
  63
  64         if (!S_ISDIR(dir->i_mode))
  65                 /*
  66                  * The parent is not a directory, which means that an extended
  67                  * attribute inode is being created. No flags.
  68                  */
  69                 return 0;
  70
  71         flags = ui->flags & (UBIFS_COMPR_FL | UBIFS_SYNC_FL | UBIFS_DIRSYNC_FL);
  72         if (!S_ISDIR(mode))
  73                 /* The "DIRSYNC" flag only applies to directories */
  74                 flags &= ~UBIFS_DIRSYNC_FL;
  75         return flags;
  76 }
  77
  78 /**
  79  * ubifs_new_inode - allocate new UBIFS inode object.
  80  * @c: UBIFS file-system description object
  81  * @dir: parent directory inode
  82  * @mode: inode mode flags
  83  *
  84  * This function finds an unused inode number, allocates new inode and
  85  * initializes it. Returns new inode in case of success and an error code in
  86  * case of failure.
  87  */
  88 struct inode *ubifs_new_inode(struct ubifs_info *c, const struct inode *dir,
  89                               int mode)
  90 {
  91         struct inode *inode;
  92         struct ubifs_inode *ui;
  93
  94         inode = new_inode(c->vfs_sb);
  95         ui = ubifs_inode(inode);
  96         if (!inode)
  97                 return ERR_PTR(-ENOMEM);
  98
  99         /*
 100          * Set 'S_NOCMTIME' to prevent VFS form updating [mc]time of inodes and
 101          * marking them dirty in file write path (see 'file_update_time()').
 102          * UBIFS has to fully control "clean <-> dirty" transitions of inodes
 103          * to make budgeting work.
 104          */
 105         inode->i_flags |= (S_NOCMTIME);
 106
 107         inode->i_uid = current->fsuid;
 108         if (dir->i_mode & S_ISGID) {
 109                 inode->i_gid = dir->i_gid;
 110                 if (S_ISDIR(mode))
 111                         mode |= S_ISGID;
 112         } else
 113                 inode->i_gid = current->fsgid;
 114         inode->i_mode = mode;
 115         inode->i_mtime = inode->i_atime = inode->i_ctime =
 116                          ubifs_current_time(inode);
 117         inode->i_mapping->nrpages = 0;
 118         /* Disable readahead */
 119         inode->i_mapping->backing_dev_info = &c->bdi;
 120
 121         switch (mode & S_IFMT) {
 122         case S_IFREG:
 123                 inode->i_mapping->a_ops = &ubifs_file_address_operations;
 124                 inode->i_op = &ubifs_file_inode_operations;
 125                 inode->i_fop = &ubifs_file_operations;
 126                 break;
 127         case S_IFDIR:
 128                 inode->i_op  = &ubifs_dir_inode_operations;
 129                 inode->i_fop = &ubifs_dir_operations;
 130                 inode->i_size = ui->ui_size = UBIFS_INO_NODE_SZ;
 131                 break;
 132         case S_IFLNK:
 133                 inode->i_op = &ubifs_symlink_inode_operations;
 134                 break;
 135         case S_IFSOCK:
 136         case S_IFIFO:
 137         case S_IFBLK:
 138         case S_IFCHR:
 139                 inode->i_op  = &ubifs_file_inode_operations;
 140                 break;
 141         default:
 142                 BUG();
 143         }
 144
 145         ui->flags = inherit_flags(dir, mode);
 146         ubifs_set_inode_flags(inode);
 147         if (S_ISREG(mode))
 148                 ui->compr_type = c->default_compr;
 149         else
 150                 ui->compr_type = UBIFS_COMPR_NONE;
 151         ui->synced_i_size = 0;
 152
 153         spin_lock(&c->cnt_lock);
 154         /* Inode number overflow is currently not supported */
 155         if (c->highest_inum >= INUM_WARN_WATERMARK) {
 156                 if (c->highest_inum >= INUM_WATERMARK) {
 157                         spin_unlock(&c->cnt_lock);
 158                         ubifs_err("out of inode numbers");
 159                         make_bad_inode(inode);
 160                         iput(inode);
 161                         return ERR_PTR(-EINVAL);
 162                 }
 163                 ubifs_warn("running out of inode numbers (current %lu, max %d)",
 164                            c->highest_inum, INUM_WATERMARK);
 165         }
 166
 167         inode->i_ino = ++c->highest_inum;
 168         inode->i_generation = ++c->vfs_gen;
 169         /*
 170          * The creation sequence number remains with this inode for its
 171          * lifetime. All nodes for this inode have a greater sequence number,
 172          * and so it is possible to distinguish obsolete nodes belonging to a
 173          * previous incarnation of the same inode number - for example, for the
 174          * purpose of rebuilding the index.
 175          */
 176         ui->creat_sqnum = ++c->max_sqnum;
 177         spin_unlock(&c->cnt_lock);
 178         return inode;
 179 }
 180
 181 #ifdef CONFIG_UBIFS_FS_DEBUG
 182
 183 static int dbg_check_name(struct ubifs_dent_node *dent, struct qstr *nm)
 184 {
 185         if (!(ubifs_chk_flags & UBIFS_CHK_GEN))
 186                 return 0;
 187         if (le16_to_cpu(dent->nlen) != nm->len)
 188                 return -EINVAL;
 189         if (memcmp(dent->name, nm->name, nm->len))
 190                 return -EINVAL;
 191         return 0;
 192 }
 193
 194 #else
 195
 196 #define dbg_check_name(dent, nm) 0
 197
 198 #endif
 199
 200 static struct dentry *ubifs_lookup(struct inode *dir, struct dentry *dentry,
 201                                    struct nameidata *nd)
 202 {
 203         int err;
 204         union ubifs_key key;
 205         struct inode *inode = NULL;
 206         struct ubifs_dent_node *dent;
 207         struct ubifs_info *c = dir->i_sb->s_fs_info;
 208
 209         dbg_gen("'%.*s' in dir ino %lu",
 210                 dentry->d_name.len, dentry->d_name.name, dir->i_ino);
 211
 212         if (dentry->d_name.len > UBIFS_MAX_NLEN)
 213                 return ERR_PTR(-ENAMETOOLONG);
 214
 215         dent = kmalloc(UBIFS_MAX_DENT_NODE_SZ, GFP_NOFS);
 216         if (!dent)
 217                 return ERR_PTR(-ENOMEM);
 218
 219         dent_key_init(c, &key, dir->i_ino, &dentry->d_name);
 220
 221         err = ubifs_tnc_lookup_nm(c, &key, dent, &dentry->d_name);
 222         if (err) {
 223                 /*
 224                  * Do not hash the direntry if parent 'i_nlink' is zero, because
 225                  * this has side-effects - '->delete_inode()' call will not be
 226                  * called for the parent orphan inode, because 'd_count' of its
 227                  * direntry will stay 1 (it'll be negative direntry I guess)
 228                  * and prevent 'iput_final()' until the dentry is destroyed due
 229                  * to unmount or memory pressure.
 230                  */
 231                 if (err == -ENOENT && dir->i_nlink != 0) {
 232                         dbg_gen("not found");
 233                         goto done;
 234                 }
 235                 goto out;
 236         }
 237
 238         if (dbg_check_name(dent, &dentry->d_name)) {
 239                 err = -EINVAL;
 240                 goto out;
 241         }
 242
 243         inode = ubifs_iget(dir->i_sb, le64_to_cpu(dent->inum));
 244         if (IS_ERR(inode)) {
 245                 /*
 246                  * This should not happen. Probably the file-system needs
 247                  * checking.
 248                  */
 249                 err = PTR_ERR(inode);
 250                 ubifs_err("dead directory entry '%.*s', error %d",
 251                           dentry->d_name.len, dentry->d_name.name, err);
 252                 ubifs_ro_mode(c, err);
 253                 goto out;
 254         }
 255
 256 done:
 257         kfree(dent);
 258         /*
 259          * Note, d_splice_alias() would be required instead if we supported
 260          * NFS.
 261          */
 262         d_add(dentry, inode);
 263         return NULL;
 264
 265 out:
 266         kfree(dent);
 267         return ERR_PTR(err);
 268 }
 269
 270 static int ubifs_create(struct inode *dir, struct dentry *dentry, int mode,
 271                         struct nameidata *nd)
 272 {
 273         struct inode *inode;
 274         struct ubifs_info *c = dir->i_sb->s_fs_info;
 275         int err, sz_change = CALC_DENT_SIZE(dentry->d_name.len);
 276         struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
 277                                         .dirtied_ino = 1 };
 278         struct ubifs_inode *dir_ui = ubifs_inode(dir);
 279
 280         /*
 281          * Budget request settings: new inode, new direntry, changing the
 282          * parent directory inode.
 283          */
 284
 285         dbg_gen("dent '%.*s', mode %#x in dir ino %lu",
 286                 dentry->d_name.len, dentry->d_name.name, mode, dir->i_ino);
 287
 288         err = ubifs_budget_space(c, &req);
 289         if (err)
 290                 return err;
 291
 292         inode = ubifs_new_inode(c, dir, mode);
 293         if (IS_ERR(inode)) {
 294                 err = PTR_ERR(inode);
 295                 goto out_budg;
 296         }
 297
 298         mutex_lock(&dir_ui->ui_mutex);
 299         dir->i_size += sz_change;
 300         dir_ui->ui_size = dir->i_size;
 301         dir->i_mtime = dir->i_ctime = inode->i_ctime;
 302         err = ubifs_jnl_update(c, dir, &dentry->d_name, inode, 0, 0);
 303         if (err)
 304                 goto out_cancel;
 305         mutex_unlock(&dir_ui->ui_mutex);
 306
 307         ubifs_release_budget(c, &req);
 308         insert_inode_hash(inode);
 309         d_instantiate(dentry, inode);
 310         return 0;
 311
 312 out_cancel:
 313         dir->i_size -= sz_change;
 314         dir_ui->ui_size = dir->i_size;
 315         mutex_unlock(&dir_ui->ui_mutex);
 316         make_bad_inode(inode);
 317         iput(inode);
 318 out_budg:
 319         ubifs_release_budget(c, &req);
 320         ubifs_err("cannot create regular file, error %d", err);
 321         return err;
 322 }
 323
 324 /**
 325  * vfs_dent_type - get VFS directory entry type.
 326  * @type: UBIFS directory entry type
 327  *
 328  * This function converts UBIFS directory entry type into VFS directory entry
 329  * type.
 330  */
 331 static unsigned int vfs_dent_type(uint8_t type)
 332 {
 333         switch (type) {
 334         case UBIFS_ITYPE_REG:
 335                 return DT_REG;
 336         case UBIFS_ITYPE_DIR:
 337                 return DT_DIR;
 338         case UBIFS_ITYPE_LNK:
 339                 return DT_LNK;
 340         case UBIFS_ITYPE_BLK:
 341                 return DT_BLK;
 342         case UBIFS_ITYPE_CHR:
 343                 return DT_CHR;
 344         case UBIFS_ITYPE_FIFO:
 345                 return DT_FIFO;
 346         case UBIFS_ITYPE_SOCK:
 347                 return DT_SOCK;
 348         default:
 349                 BUG();
 350         }
 351         return 0;
 352 }
 353
 354 /*
 355  * The classical Unix view for directory is that it is a linear array of
 356  * (name, inode number) entries. Linux/VFS assumes this model as well.
 357  * Particularly, 'readdir()' call wants us to return a directory entry offset
 358  * which later may be used to continue 'readdir()'ing the directory or to
 359  * 'seek()' to that specific direntry. Obviously UBIFS does not really fit this
 360  * model because directory entries are identified by keys, which may collide.
 361  *
 362  * UBIFS uses directory entry hash value for directory offsets, so
 363  * 'seekdir()'/'telldir()' may not always work because of possible key
 364  * collisions. But UBIFS guarantees that consecutive 'readdir()' calls work
 365  * properly by means of saving full directory entry name in the private field
 366  * of the file description object.
 367  *
 368  * This means that UBIFS cannot support NFS which requires full
 369  * 'seekdir()'/'telldir()' support.
 370  */
 371 static int ubifs_readdir(struct file *file, void *dirent, filldir_t filldir)
 372 {
 373         int err, over = 0;
 374         struct qstr nm;
 375         union ubifs_key key;
 376         struct ubifs_dent_node *dent;
 377         struct inode *dir = file->f_path.dentry->d_inode;
 378         struct ubifs_info *c = dir->i_sb->s_fs_info;
 379
 380         dbg_gen("dir ino %lu, f_pos %#llx", dir->i_ino, file->f_pos);
 381
 382         if (file->f_pos > UBIFS_S_KEY_HASH_MASK || file->f_pos == 2)
 383                 /*
 384                  * The directory was seek'ed to a senseless position or there
 385                  * are no more entries.
 386                  */
 387                 return 0;
 388
 389         /* File positions 0 and 1 correspond to "." and ".." */
 390         if (file->f_pos == 0) {
 391                 ubifs_assert(!file->private_data);
 392                 over = filldir(dirent, ".", 1, 0, dir->i_ino, DT_DIR);
 393                 if (over)
 394                         return 0;
 395                 file->f_pos = 1;
 396         }
 397
 398         if (file->f_pos == 1) {
 399                 ubifs_assert(!file->private_data);
 400                 over = filldir(dirent, "..", 2, 1,
 401                                parent_ino(file->f_path.dentry), DT_DIR);
 402                 if (over)
 403                         return 0;
 404
 405                 /* Find the first entry in TNC and save it */
 406                 lowest_dent_key(c, &key, dir->i_ino);
 407                 nm.name = NULL;
 408                 dent = ubifs_tnc_next_ent(c, &key, &nm);
 409                 if (IS_ERR(dent)) {
 410                         err = PTR_ERR(dent);
 411                         goto out;
 412                 }
 413
 414                 file->f_pos = key_hash_flash(c, &dent->key);
 415                 file->private_data = dent;
 416         }
 417
 418         dent = file->private_data;
 419         if (!dent) {
 420                 /*
 421                  * The directory was seek'ed to and is now readdir'ed.
 422                  * Find the entry corresponding to @file->f_pos or the
 423                  * closest one.
 424                  */
 425                 dent_key_init_hash(c, &key, dir->i_ino, file->f_pos);
 426                 nm.name = NULL;
 427                 dent = ubifs_tnc_next_ent(c, &key, &nm);
 428                 if (IS_ERR(dent)) {
 429                         err = PTR_ERR(dent);
 430                         goto out;
 431                 }
 432                 file->f_pos = key_hash_flash(c, &dent->key);
 433                 file->private_data = dent;
 434         }
 435
 436         while (1) {
 437                 dbg_gen("feed '%s', ino %llu, new f_pos %#x",
 438                         dent->name, le64_to_cpu(dent->inum),
 439                         key_hash_flash(c, &dent->key));
 440                 ubifs_assert(dent->ch.sqnum > ubifs_inode(dir)->creat_sqnum);
 441
 442                 nm.len = le16_to_cpu(dent->nlen);
 443                 over = filldir(dirent, dent->name, nm.len, file->f_pos,
 444                                le64_to_cpu(dent->inum),
 445                                vfs_dent_type(dent->type));
 446                 if (over)
 447                         return 0;
 448
 449                 /* Switch to the next entry */
 450                 key_read(c, &dent->key, &key);
 451                 nm.name = dent->name;
 452                 dent = ubifs_tnc_next_ent(c, &key, &nm);
 453                 if (IS_ERR(dent)) {
 454                         err = PTR_ERR(dent);
 455                         goto out;
 456                 }
 457
 458                 kfree(file->private_data);
 459                 file->f_pos = key_hash_flash(c, &dent->key);
 460                 file->private_data = dent;
 461                 cond_resched();
 462         }
 463
 464 out:
 465         if (err != -ENOENT) {
 466                 ubifs_err("cannot find next direntry, error %d", err);
 467                 return err;
 468         }
 469
 470         kfree(file->private_data);
 471         file->private_data = NULL;
 472         file->f_pos = 2;
 473         return 0;
 474 }
 475
 476 /* If a directory is seeked, we have to free saved readdir() state */
 477 static loff_t ubifs_dir_llseek(struct file *file, loff_t offset, int origin)
 478 {
 479         kfree(file->private_data);
 480         file->private_data = NULL;
 481         return generic_file_llseek(file, offset, origin);
 482 }
 483
 484 /* Free saved readdir() state when the directory is closed */
 485 static int ubifs_dir_release(struct inode *dir, struct file *file)
 486 {
 487         kfree(file->private_data);
 488         file->private_data = NULL;
 489         return 0;
 490 }
 491
 492 /**
 493  * lock_2_inodes - lock two UBIFS inodes.
 494  * @inode1: first inode
 495  * @inode2: second inode
 496  */
 497 static void lock_2_inodes(struct inode *inode1, struct inode *inode2)
 498 {
 499         if (inode1->i_ino < inode2->i_ino) {
 500                 mutex_lock_nested(&ubifs_inode(inode1)->ui_mutex, WB_MUTEX_2);
 501                 mutex_lock_nested(&ubifs_inode(inode2)->ui_mutex, WB_MUTEX_3);
 502         } else {
 503                 mutex_lock_nested(&ubifs_inode(inode2)->ui_mutex, WB_MUTEX_2);
 504                 mutex_lock_nested(&ubifs_inode(inode1)->ui_mutex, WB_MUTEX_3);
 505         }
 506 }
 507
 508 /**
 509  * unlock_2_inodes - unlock two UBIFS inodes inodes.
 510  * @inode1: first inode
 511  * @inode2: second inode
 512  */
 513 static void unlock_2_inodes(struct inode *inode1, struct inode *inode2)
 514 {
 515         mutex_unlock(&ubifs_inode(inode1)->ui_mutex);
 516         mutex_unlock(&ubifs_inode(inode2)->ui_mutex);
 517 }
 518
 519 static int ubifs_link(struct dentry *old_dentry, struct inode *dir,
 520                       struct dentry *dentry)
 521 {
 522         struct ubifs_info *c = dir->i_sb->s_fs_info;
 523         struct inode *inode = old_dentry->d_inode;
 524         struct ubifs_inode *ui = ubifs_inode(inode);
 525         struct ubifs_inode *dir_ui = ubifs_inode(dir);
 526         int err, sz_change = CALC_DENT_SIZE(dentry->d_name.len);
 527         struct ubifs_budget_req req = { .new_dent = 1, .dirtied_ino = 2,
 528                                         .dirtied_ino_d = ui->data_len };
 529
 530         /*
 531          * Budget request settings: new direntry, changing the target inode,
 532          * changing the parent inode.
 533          */
 534
 535         dbg_gen("dent '%.*s' to ino %lu (nlink %d) in dir ino %lu",
 536                 dentry->d_name.len, dentry->d_name.name, inode->i_ino,
 537                 inode->i_nlink, dir->i_ino);
 538         err = dbg_check_synced_i_size(inode);
 539         if (err)
 540                 return err;
 541
 542         err = ubifs_budget_space(c, &req);
 543         if (err)
 544                 return err;
 545
 546         lock_2_inodes(dir, inode);
 547         inc_nlink(inode);
 548         atomic_inc(&inode->i_count);
 549         inode->i_ctime = ubifs_current_time(inode);
 550         dir->i_size += sz_change;
 551         dir_ui->ui_size = dir->i_size;
 552         dir->i_mtime = dir->i_ctime = inode->i_ctime;
 553         err = ubifs_jnl_update(c, dir, &dentry->d_name, inode, 0, 0);
 554         if (err)
 555                 goto out_cancel;
 556         unlock_2_inodes(dir, inode);
 557
 558         ubifs_release_budget(c, &req);
 559         d_instantiate(dentry, inode);
 560         return 0;
 561
 562 out_cancel:
 563         dir->i_size -= sz_change;
 564         dir_ui->ui_size = dir->i_size;
 565         drop_nlink(inode);
 566         unlock_2_inodes(dir, inode);
 567         ubifs_release_budget(c, &req);
 568         iput(inode);
 569         return err;
 570 }
 571
 572 static int ubifs_unlink(struct inode *dir, struct dentry *dentry)
 573 {
 574         struct ubifs_info *c = dir->i_sb->s_fs_info;
 575         struct inode *inode = dentry->d_inode;
 576         struct ubifs_inode *dir_ui = ubifs_inode(dir);
 577         int sz_change = CALC_DENT_SIZE(dentry->d_name.len);
 578         int err, budgeted = 1;
 579         struct ubifs_budget_req req = { .mod_dent = 1, .dirtied_ino = 2 };
 580
 581         /*
 582          * Budget request settings: deletion direntry, deletion inode (+1 for
 583          * @dirtied_ino), changing the parent directory inode. If budgeting
 584          * fails, go ahead anyway because we have extra space reserved for
 585          * deletions.
 586          */
 587
 588         dbg_gen("dent '%.*s' from ino %lu (nlink %d) in dir ino %lu",
 589                 dentry->d_name.len, dentry->d_name.name, inode->i_ino,
 590                 inode->i_nlink, dir->i_ino);
 591         err = dbg_check_synced_i_size(inode);
 592         if (err)
 593                 return err;
 594
 595         err = ubifs_budget_space(c, &req);
 596         if (err) {
 597                 if (err != -ENOSPC)
 598                         return err;
 599                 err = 0;
 600                 budgeted = 0;
 601         }
 602
 603         lock_2_inodes(dir, inode);
 604         inode->i_ctime = ubifs_current_time(dir);
 605         drop_nlink(inode);
 606         dir->i_size -= sz_change;
 607         dir_ui->ui_size = dir->i_size;
 608         dir->i_mtime = dir->i_ctime = inode->i_ctime;
 609         err = ubifs_jnl_update(c, dir, &dentry->d_name, inode, 1, 0);
 610         if (err)
 611                 goto out_cancel;
 612         unlock_2_inodes(dir, inode);
 613
 614         if (budgeted)
 615                 ubifs_release_budget(c, &req);
 616         else {
 617                 /* We've deleted something - clean the "no space" flags */
 618                 c->nospace = c->nospace_rp = 0;
 619                 smp_wmb();
 620         }
 621         return 0;
 622
 623 out_cancel:
 624         dir->i_size += sz_change;
 625         dir_ui->ui_size = dir->i_size;
 626         inc_nlink(inode);
 627         unlock_2_inodes(dir, inode);
 628         if (budgeted)
 629                 ubifs_release_budget(c, &req);
 630         return err;
 631 }
 632
 633 /**
 634  * check_dir_empty - check if a directory is empty or not.
 635  * @c: UBIFS file-system description object
 636  * @dir: VFS inode object of the directory to check
 637  *
 638  * This function checks if directory @dir is empty. Returns zero if the
 639  * directory is empty, %-ENOTEMPTY if it is not, and other negative error codes
 640  * in case of of errors.
 641  */
 642 static int check_dir_empty(struct ubifs_info *c, struct inode *dir)
 643 {
 644         struct qstr nm = { .name = NULL };
 645         struct ubifs_dent_node *dent;
 646         union ubifs_key key;
 647         int err;
 648
 649         lowest_dent_key(c, &key, dir->i_ino);
 650         dent = ubifs_tnc_next_ent(c, &key, &nm);
 651         if (IS_ERR(dent)) {
 652                 err = PTR_ERR(dent);
 653                 if (err == -ENOENT)
 654                         err = 0;
 655         } else {
 656                 kfree(dent);
 657                 err = -ENOTEMPTY;
 658         }
 659         return err;
 660 }
 661
 662 static int ubifs_rmdir(struct inode *dir, struct dentry *dentry)
 663 {
 664         struct ubifs_info *c = dir->i_sb->s_fs_info;
 665         struct inode *inode = dentry->d_inode;
 666         int sz_change = CALC_DENT_SIZE(dentry->d_name.len);
 667         int err, budgeted = 1;
 668         struct ubifs_inode *dir_ui = ubifs_inode(dir);
 669         struct ubifs_budget_req req = { .mod_dent = 1, .dirtied_ino = 2 };
 670
 671         /*
 672          * Budget request settings: deletion direntry, deletion inode and
 673          * changing the parent inode. If budgeting fails, go ahead anyway
 674          * because we have extra space reserved for deletions.
 675          */
 676
 677         dbg_gen("directory '%.*s', ino %lu in dir ino %lu", dentry->d_name.len,
 678                 dentry->d_name.name, inode->i_ino, dir->i_ino);
 679
 680         err = check_dir_empty(c, dentry->d_inode);
 681         if (err)
 682                 return err;
 683
 684         err = ubifs_budget_space(c, &req);
 685         if (err) {
 686                 if (err != -ENOSPC)
 687                         return err;
 688                 budgeted = 0;
 689         }
 690
 691         lock_2_inodes(dir, inode);
 692         inode->i_ctime = ubifs_current_time(dir);
 693         clear_nlink(inode);
 694         drop_nlink(dir);
 695         dir->i_size -= sz_change;
 696         dir_ui->ui_size = dir->i_size;
 697         dir->i_mtime = dir->i_ctime = inode->i_ctime;
 698         err = ubifs_jnl_update(c, dir, &dentry->d_name, inode, 1, 0);
 699         if (err)
 700                 goto out_cancel;
 701         unlock_2_inodes(dir, inode);
 702
 703         if (budgeted)
 704                 ubifs_release_budget(c, &req);
 705         else {
 706                 /* We've deleted something - clean the "no space" flags */
 707                 c->nospace = c->nospace_rp = 0;
 708                 smp_wmb();
 709         }
 710         return 0;
 711
 712 out_cancel:
 713         dir->i_size += sz_change;
 714         dir_ui->ui_size = dir->i_size;
 715         inc_nlink(dir);
 716         inc_nlink(inode);
 717         inc_nlink(inode);
 718         unlock_2_inodes(dir, inode);
 719         if (budgeted)
 720                 ubifs_release_budget(c, &req);
 721         return err;
 722 }
 723
 724 static int ubifs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 725 {
 726         struct inode *inode;
 727         struct ubifs_inode *dir_ui = ubifs_inode(dir);
 728         struct ubifs_info *c = dir->i_sb->s_fs_info;
 729         int err, sz_change = CALC_DENT_SIZE(dentry->d_name.len);
 730         struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
 731                                         .dirtied_ino_d = 1 };
 732
 733         /*
 734          * Budget request settings: new inode, new direntry and changing parent
 735          * directory inode.
 736          */
 737
 738         dbg_gen("dent '%.*s', mode %#x in dir ino %lu",
 739                 dentry->d_name.len, dentry->d_name.name, mode, dir->i_ino);
 740
 741         err = ubifs_budget_space(c, &req);
 742         if (err)
 743                 return err;
 744
 745         inode = ubifs_new_inode(c, dir, S_IFDIR | mode);
 746         if (IS_ERR(inode)) {
 747                 err = PTR_ERR(inode);
 748                 goto out_budg;
 749         }
 750
 751         mutex_lock(&dir_ui->ui_mutex);
 752         insert_inode_hash(inode);
 753         inc_nlink(inode);
 754         inc_nlink(dir);
 755         dir->i_size += sz_change;
 756         dir_ui->ui_size = dir->i_size;
 757         dir->i_mtime = dir->i_ctime = inode->i_ctime;
 758         err = ubifs_jnl_update(c, dir, &dentry->d_name, inode, 0, 0);
 759         if (err) {
 760                 ubifs_err("cannot create directory, error %d", err);
 761                 goto out_cancel;
 762         }
 763         mutex_unlock(&dir_ui->ui_mutex);
 764
 765         ubifs_release_budget(c, &req);
 766         d_instantiate(dentry, inode);
 767         return 0;
 768
 769 out_cancel:
 770         dir->i_size -= sz_change;
 771         dir_ui->ui_size = dir->i_size;
 772         drop_nlink(dir);
 773         mutex_unlock(&dir_ui->ui_mutex);
 774         make_bad_inode(inode);
 775         iput(inode);
 776 out_budg:
 777         ubifs_release_budget(c, &req);
 778         return err;
 779 }
 780
 781 static int ubifs_mknod(struct inode *dir, struct dentry *dentry,
 782                        int mode, dev_t rdev)
 783 {
 784         struct inode *inode;
 785         struct ubifs_inode *ui;
 786         struct ubifs_inode *dir_ui = ubifs_inode(dir);
 787         struct ubifs_info *c = dir->i_sb->s_fs_info;
 788         union ubifs_dev_desc *dev = NULL;
 789         int sz_change = CALC_DENT_SIZE(dentry->d_name.len);
 790         int err, devlen = 0;
 791         struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
 792                                         .new_ino_d = devlen, .dirtied_ino = 1 };
 793
 794         /*
 795          * Budget request settings: new inode, new direntry and changing parent
 796          * directory inode.
 797          */
 798
 799         dbg_gen("dent '%.*s' in dir ino %lu",
 800                 dentry->d_name.len, dentry->d_name.name, dir->i_ino);
 801
 802         if (!new_valid_dev(rdev))
 803                 return -EINVAL;
 804
 805         if (S_ISBLK(mode) || S_ISCHR(mode)) {
 806                 dev = kmalloc(sizeof(union ubifs_dev_desc), GFP_NOFS);
 807                 if (!dev)
 808                         return -ENOMEM;
 809                 devlen = ubifs_encode_dev(dev, rdev);
 810         }
 811
 812         err = ubifs_budget_space(c, &req);
 813         if (err) {
 814                 kfree(dev);
 815                 return err;
 816         }
 817
 818         inode = ubifs_new_inode(c, dir, mode);
 819         if (IS_ERR(inode)) {
 820                 kfree(dev);
 821                 err = PTR_ERR(inode);
 822                 goto out_budg;
 823         }
 824
 825         init_special_inode(inode, inode->i_mode, rdev);
 826         inode->i_size = ubifs_inode(inode)->ui_size = devlen;
 827         ui = ubifs_inode(inode);
 828         ui->data = dev;
 829         ui->data_len = devlen;
 830
 831         mutex_lock(&dir_ui->ui_mutex);
 832         dir->i_size += sz_change;
 833         dir_ui->ui_size = dir->i_size;
 834         dir->i_mtime = dir->i_ctime = inode->i_ctime;
 835         err = ubifs_jnl_update(c, dir, &dentry->d_name, inode, 0, 0);
 836         if (err)
 837                 goto out_cancel;
 838         mutex_unlock(&dir_ui->ui_mutex);
 839
 840         ubifs_release_budget(c, &req);
 841         insert_inode_hash(inode);
 842         d_instantiate(dentry, inode);
 843         return 0;
 844
 845 out_cancel:
 846         dir->i_size -= sz_change;
 847         dir_ui->ui_size = dir->i_size;
 848         mutex_unlock(&dir_ui->ui_mutex);
 849         make_bad_inode(inode);
 850         iput(inode);
 851 out_budg:
 852         ubifs_release_budget(c, &req);
 853         return err;
 854 }
 855
 856 static int ubifs_symlink(struct inode *dir, struct dentry *dentry,
 857                          const char *symname)
 858 {
 859         struct inode *inode;
 860         struct ubifs_inode *ui;
 861         struct ubifs_inode *dir_ui = ubifs_inode(dir);
 862         struct ubifs_info *c = dir->i_sb->s_fs_info;
 863         int err, len = strlen(symname);
 864         int sz_change = CALC_DENT_SIZE(dentry->d_name.len);
 865         struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
 866                                         .new_ino_d = len, .dirtied_ino = 1 };
 867
 868         /*
 869          * Budget request settings: new inode, new direntry and changing parent
 870          * directory inode.
 871          */
 872
 873         dbg_gen("dent '%.*s', target '%s' in dir ino %lu", dentry->d_name.len,
 874                 dentry->d_name.name, symname, dir->i_ino);
 875
 876         if (len > UBIFS_MAX_INO_DATA)
 877                 return -ENAMETOOLONG;
 878
 879         err = ubifs_budget_space(c, &req);
 880         if (err)
 881                 return err;
 882
 883         inode = ubifs_new_inode(c, dir, S_IFLNK | S_IRWXUGO);
 884         if (IS_ERR(inode)) {
 885                 err = PTR_ERR(inode);
 886                 goto out_budg;
 887         }
 888
 889         ui = ubifs_inode(inode);
 890         ui->data = kmalloc(len + 1, GFP_NOFS);
 891         if (!ui->data) {
 892                 err = -ENOMEM;
 893                 goto out_inode;
 894         }
 895
 896         memcpy(ui->data, symname, len);
 897         ((char *)ui->data)[len] = '\0';
 898         /*
 899          * The terminating zero byte is not written to the flash media and it
 900          * is put just to make later in-memory string processing simpler. Thus,
 901          * data length is @len, not @len + %1.
 902          */
 903         ui->data_len = len;
 904         inode->i_size = ubifs_inode(inode)->ui_size = len;
 905
 906         mutex_lock(&dir_ui->ui_mutex);
 907         dir->i_size += sz_change;
 908         dir_ui->ui_size = dir->i_size;
 909         dir->i_mtime = dir->i_ctime = inode->i_ctime;
 910         err = ubifs_jnl_update(c, dir, &dentry->d_name, inode, 0, 0);
 911         if (err)
 912                 goto out_cancel;
 913         mutex_unlock(&dir_ui->ui_mutex);
 914
 915         ubifs_release_budget(c, &req);
 916         insert_inode_hash(inode);
 917         d_instantiate(dentry, inode);
 918         return 0;
 919
 920 out_cancel:
 921         dir->i_size -= sz_change;
 922         dir_ui->ui_size = dir->i_size;
 923         mutex_unlock(&dir_ui->ui_mutex);
 924 out_inode:
 925         make_bad_inode(inode);
 926         iput(inode);
 927 out_budg:
 928         ubifs_release_budget(c, &req);
 929         return err;
 930 }
 931
 932 /**
 933  * lock_3_inodes - lock three UBIFS inodes for rename.
 934  * @inode1: first inode
 935  * @inode2: second inode
 936  * @inode3: third inode
 937  *
 938  * For 'ubifs_rename()', @inode1 may be the same as @inode2 whereas @inode3 may
 939  * be null.
 940  */
 941 static void lock_3_inodes(struct inode *inode1, struct inode *inode2,
 942                           struct inode *inode3)
 943 {
 944         struct inode *i1, *i2, *i3;
 945
 946         if (!inode3) {
 947                 if (inode1 != inode2) {
 948                         lock_2_inodes(inode1, inode2);
 949                         return;
 950                 }
 951                 mutex_lock_nested(&ubifs_inode(inode1)->ui_mutex, WB_MUTEX_1);
 952                 return;
 953         }
 954
 955         if (inode1 == inode2) {
 956                 lock_2_inodes(inode1, inode3);
 957                 return;
 958         }
 959
 960         /* 3 different inodes */
 961         if (inode1 < inode2) {
 962                 i3 = inode2;
 963                 if (inode1 < inode3) {
 964                         i1 = inode1;
 965                         i2 = inode3;
 966                 } else {
 967                         i1 = inode3;
 968                         i2 = inode1;
 969                 }
 970         } else {
 971                 i3 = inode1;
 972                 if (inode2 < inode3) {
 973                         i1 = inode2;
 974                         i2 = inode3;
 975                 } else {
 976                         i1 = inode3;
 977                         i2 = inode2;
 978                 }
 979         }
 980         mutex_lock_nested(&ubifs_inode(i1)->ui_mutex, WB_MUTEX_1);
 981         lock_2_inodes(i2, i3);
 982 }
 983
 984 /**
 985  * unlock_3_inodes - unlock three UBIFS inodes for rename.
 986  * @inode1: first inode
 987  * @inode2: second inode
 988  * @inode3: third inode
 989  */
 990 static void unlock_3_inodes(struct inode *inode1, struct inode *inode2,
 991                             struct inode *inode3)
 992 {
 993         mutex_unlock(&ubifs_inode(inode1)->ui_mutex);
 994         if (inode1 != inode2)
 995                 mutex_unlock(&ubifs_inode(inode2)->ui_mutex);
 996         if (inode3)
 997                 mutex_unlock(&ubifs_inode(inode3)->ui_mutex);
 998 }
 999
1000 static int ubifs_rename(struct inode *old_dir, struct dentry *old_dentry,
1001                         struct inode *new_dir, struct dentry *new_dentry)
1002 {
1003         struct ubifs_info *c = old_dir->i_sb->s_fs_info;
1004         struct inode *old_inode = old_dentry->d_inode;
1005         struct inode *new_inode = new_dentry->d_inode;
1006         struct ubifs_inode *old_inode_ui = ubifs_inode(old_inode);
1007         int err, release, sync = 0, move = (new_dir != old_dir);
1008         int is_dir = S_ISDIR(old_inode->i_mode);
1009         int unlink = !!new_inode;
1010         int new_sz = CALC_DENT_SIZE(new_dentry->d_name.len);
1011         int old_sz = CALC_DENT_SIZE(old_dentry->d_name.len);
1012         struct ubifs_budget_req req = { .new_dent = 1, .mod_dent = 1,
1013                                         .dirtied_ino = 3 };
1014         struct ubifs_budget_req ino_req = { .dirtied_ino = 1,
1015                                 .dirtied_ino_d = old_inode_ui->data_len };
1016         struct timespec time;
1017
1018         /*
1019          * Budget request settings: deletion direntry, new direntry, removing
1020          * the old inode, and changing old and new parent directory inodes.
1021          *
1022          * However, this operation also marks the target inode as dirty and
1023          * does not write it, so we allocate budget for the target inode
1024          * separately.
1025          */
1026
1027         dbg_gen("dent '%.*s' ino %lu in dir ino %lu to dent '%.*s' in "
1028                 "dir ino %lu", old_dentry->d_name.len, old_dentry->d_name.name,
1029                 old_inode->i_ino, old_dir->i_ino, new_dentry->d_name.len,
1030                 new_dentry->d_name.name, new_dir->i_ino);
1031
1032         if (unlink && is_dir) {
1033                 err = check_dir_empty(c, new_inode);
1034                 if (err)
1035                         return err;
1036         }
1037
1038         err = ubifs_budget_space(c, &req);
1039         if (err)
1040                 return err;
1041         err = ubifs_budget_space(c, &ino_req);
1042         if (err) {
1043                 ubifs_release_budget(c, &req);
1044                 return err;
1045         }
1046
1047         lock_3_inodes(old_dir, new_dir, new_inode);
1048
1049         /*
1050          * Like most other Unix systems, set the @i_ctime for inodes on a
1051          * rename.
1052          */
1053         time = ubifs_current_time(old_dir);
1054         old_inode->i_ctime = time;
1055
1056         /* We must adjust parent link count when renaming directories */
1057         if (is_dir) {
1058                 if (move) {
1059                         /*
1060                          * @old_dir loses a link because we are moving
1061                          * @old_inode to a different directory.
1062                          */
1063                         drop_nlink(old_dir);
1064                         /*
1065                          * @new_dir only gains a link if we are not also
1066                          * overwriting an existing directory.
1067                          */
1068                         if (!unlink)
1069                                 inc_nlink(new_dir);
1070                 } else {
1071                         /*
1072                          * @old_inode is not moving to a different directory,
1073                          * but @old_dir still loses a link if we are
1074                          * overwriting an existing directory.
1075                          */
1076                         if (unlink)
1077                                 drop_nlink(old_dir);
1078                 }
1079         }
1080
1081         old_dir->i_size -= old_sz;
1082         ubifs_inode(old_dir)->ui_size = old_dir->i_size;
1083         old_dir->i_mtime = old_dir->i_ctime = time;
1084         new_dir->i_mtime = new_dir->i_ctime = time;
1085
1086         /*
1087          * And finally, if we unlinked a direntry which happened to have the
1088          * same name as the moved direntry, we have to decrement @i_nlink of
1089          * the unlinked inode and change its ctime.
1090          */
1091         if (unlink) {
1092                 /*
1093                  * Directories cannot have hard-links, so if this is a
1094                  * directory, decrement its @i_nlink twice because an empty
1095                  * directory has @i_nlink 2.
1096                  */
1097                 if (is_dir)
1098                         drop_nlink(new_inode);
1099                 new_inode->i_ctime = time;
1100                 drop_nlink(new_inode);
1101         } else {
1102                 new_dir->i_size += new_sz;
1103                 ubifs_inode(new_dir)->ui_size = new_dir->i_size;
1104         }
1105
1106         /*
1107          * Do not ask 'ubifs_jnl_rename()' to flush write-buffer if @old_inode
1108          * is dirty, because this will be done later on at the end of
1109          * 'ubifs_rename()'.
1110          */
1111         if (IS_SYNC(old_inode)) {
1112                 sync = IS_DIRSYNC(old_dir) || IS_DIRSYNC(new_dir);
1113                 if (unlink && IS_SYNC(new_inode))
1114                         sync = 1;
1115         }
1116         err = ubifs_jnl_rename(c, old_dir, old_dentry, new_dir, new_dentry,
1117                                sync);
1118         if (err)
1119                 goto out_cancel;
1120
1121         unlock_3_inodes(old_dir, new_dir, new_inode);
1122         ubifs_release_budget(c, &req);
1123
1124         mutex_lock(&old_inode_ui->ui_mutex);
1125         release = old_inode_ui->dirty;
1126         mark_inode_dirty_sync(old_inode);
1127         mutex_unlock(&old_inode_ui->ui_mutex);
1128
1129         if (release)
1130                 ubifs_release_budget(c, &ino_req);
1131         if (IS_SYNC(old_inode))
1132                 err = old_inode->i_sb->s_op->write_inode(old_inode, 1);
1133         return err;
1134
1135 out_cancel:
1136         if (unlink) {
1137                 if (is_dir)
1138                         inc_nlink(new_inode);
1139                 inc_nlink(new_inode);
1140         } else {
1141                 new_dir->i_size -= new_sz;
1142                 ubifs_inode(new_dir)->ui_size = new_dir->i_size;
1143         }
1144         old_dir->i_size += old_sz;
1145         ubifs_inode(old_dir)->ui_size = old_dir->i_size;
1146         if (is_dir) {
1147                 if (move) {
1148                         inc_nlink(old_dir);
1149                         if (!unlink)
1150                                 drop_nlink(new_dir);
1151                 } else {
1152                         if (unlink)
1153                                 inc_nlink(old_dir);
1154                 }
1155         }
1156         unlock_3_inodes(old_dir, new_dir, new_inode);
1157         ubifs_release_budget(c, &ino_req);
1158         ubifs_release_budget(c, &req);
1159         return err;
1160 }
1161
1162 int ubifs_getattr(struct vfsmount *mnt, struct dentry *dentry,
1163                   struct kstat *stat)
1164 {
1165         loff_t size;
1166         struct inode *inode = dentry->d_inode;
1167         struct ubifs_inode *ui = ubifs_inode(inode);
1168
1169         mutex_lock(&ui->ui_mutex);
1170         stat->dev = inode->i_sb->s_dev;
1171         stat->ino = inode->i_ino;
1172         stat->mode = inode->i_mode;
1173         stat->nlink = inode->i_nlink;
1174         stat->uid = inode->i_uid;
1175         stat->gid = inode->i_gid;
1176         stat->rdev = inode->i_rdev;
1177         stat->atime = inode->i_atime;
1178         stat->mtime = inode->i_mtime;
1179         stat->ctime = inode->i_ctime;
1180         stat->blksize = UBIFS_BLOCK_SIZE;
1181         stat->size = ui->ui_size;
1182
1183         /*
1184          * Unfortunately, the 'stat()' system call was designed for block
1185          * device based file systems, and it is not appropriate for UBIFS,
1186          * because UBIFS does not have notion of "block". For example, it is
1187          * difficult to tell how many block a directory takes - it actually
1188          * takes less than 300 bytes, but we have to round it to block size,
1189          * which introduces large mistake. This makes utilities like 'du' to
1190          * report completely senseless numbers. This is the reason why UBIFS
1191          * goes the same way as JFFS2 - it reports zero blocks for everything
1192          * but regular files, which makes more sense than reporting completely
1193          * wrong sizes.
1194          */
1195         if (S_ISREG(inode->i_mode)) {
1196                 size = ui->xattr_size;
1197                 size += stat->size;
1198                 size = ALIGN(size, UBIFS_BLOCK_SIZE);
1199                 /*
1200                  * Note, user-space expects 512-byte blocks count irrespectively
1201                  * of what was reported in @stat->size.
1202                  */
1203                 stat->blocks = size >> 9;
1204         } else
1205                 stat->blocks = 0;
1206         mutex_unlock(&ui->ui_mutex);
1207         return 0;
1208 }
1209
1210 struct inode_operations ubifs_dir_inode_operations = {
1211         .lookup      = ubifs_lookup,
1212         .create      = ubifs_create,
1213         .link        = ubifs_link,
1214         .symlink     = ubifs_symlink,
1215         .unlink      = ubifs_unlink,
1216         .mkdir       = ubifs_mkdir,
1217         .rmdir       = ubifs_rmdir,
1218         .mknod       = ubifs_mknod,
1219         .rename      = ubifs_rename,
1220         .setattr     = ubifs_setattr,
1221         .getattr     = ubifs_getattr,
1222 #ifdef CONFIG_UBIFS_FS_XATTR
1223         .setxattr    = ubifs_setxattr,
1224         .getxattr    = ubifs_getxattr,
1225         .listxattr   = ubifs_listxattr,
1226         .removexattr = ubifs_removexattr,
1227 #endif
1228 };
1229
1230 struct file_operations ubifs_dir_operations = {
1231         .llseek         = ubifs_dir_llseek,
1232         .release        = ubifs_dir_release,
1233         .read           = generic_read_dir,
1234         .readdir        = ubifs_readdir,
1235         .fsync          = ubifs_fsync,
1236         .unlocked_ioctl = ubifs_ioctl,
1237 #ifdef CONFIG_COMPAT
1238         .compat_ioctl   = ubifs_compat_ioctl,
1239 #endif
1240 };