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