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_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 #ifdef CONFIG_UBIFS_FS_DEBUG
 174
 175 static int dbg_check_name(struct ubifs_dent_node *dent, struct qstr *nm)
 176 {
 177         if (!(ubifs_chk_flags & UBIFS_CHK_GEN))
 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 #else
 187
 188 #define dbg_check_name(dent, nm) 0
 189
 190 #endif
 191
 192 static struct dentry *ubifs_lookup(struct inode *dir, struct dentry *dentry,
 193                                    struct nameidata *nd)
 194 {
 195         int err;
 196         union ubifs_key key;
 197         struct inode *inode = NULL;
 198         struct ubifs_dent_node *dent;
 199         struct ubifs_info *c = dir->i_sb->s_fs_info;
 200
 201         dbg_gen("'%.*s' in dir ino %lu",
 202                 dentry->d_name.len, dentry->d_name.name, dir->i_ino);
 203
 204         if (dentry->d_name.len > UBIFS_MAX_NLEN)
 205                 return ERR_PTR(-ENAMETOOLONG);
 206
 207         dent = kmalloc(UBIFS_MAX_DENT_NODE_SZ, GFP_NOFS);
 208         if (!dent)
 209                 return ERR_PTR(-ENOMEM);
 210
 211         dent_key_init(c, &key, dir->i_ino, &dentry->d_name);
 212
 213         err = ubifs_tnc_lookup_nm(c, &key, dent, &dentry->d_name);
 214         if (err) {
 215                 if (err == -ENOENT) {
 216                         dbg_gen("not found");
 217                         goto done;
 218                 }
 219                 goto out;
 220         }
 221
 222         if (dbg_check_name(dent, &dentry->d_name)) {
 223                 err = -EINVAL;
 224                 goto out;
 225         }
 226
 227         inode = ubifs_iget(dir->i_sb, le64_to_cpu(dent->inum));
 228         if (IS_ERR(inode)) {
 229                 /*
 230                  * This should not happen. Probably the file-system needs
 231                  * checking.
 232                  */
 233                 err = PTR_ERR(inode);
 234                 ubifs_err("dead directory entry '%.*s', error %d",
 235                           dentry->d_name.len, dentry->d_name.name, err);
 236                 ubifs_ro_mode(c, err);
 237                 goto out;
 238         }
 239
 240 done:
 241         kfree(dent);
 242         /*
 243          * Note, d_splice_alias() would be required instead if we supported
 244          * NFS.
 245          */
 246         d_add(dentry, inode);
 247         return NULL;
 248
 249 out:
 250         kfree(dent);
 251         return ERR_PTR(err);
 252 }
 253
 254 static int ubifs_create(struct inode *dir, struct dentry *dentry, int mode,
 255                         struct nameidata *nd)
 256 {
 257         struct inode *inode;
 258         struct ubifs_info *c = dir->i_sb->s_fs_info;
 259         int err, sz_change = CALC_DENT_SIZE(dentry->d_name.len);
 260         struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
 261                                         .dirtied_ino = 1 };
 262         struct ubifs_inode *dir_ui = ubifs_inode(dir);
 263
 264         /*
 265          * Budget request settings: new inode, new direntry, changing the
 266          * parent directory inode.
 267          */
 268
 269         dbg_gen("dent '%.*s', mode %#x in dir ino %lu",
 270                 dentry->d_name.len, dentry->d_name.name, mode, dir->i_ino);
 271
 272         err = ubifs_budget_space(c, &req);
 273         if (err)
 274                 return err;
 275
 276         inode = ubifs_new_inode(c, dir, mode);
 277         if (IS_ERR(inode)) {
 278                 err = PTR_ERR(inode);
 279                 goto out_budg;
 280         }
 281
 282         mutex_lock(&dir_ui->ui_mutex);
 283         dir->i_size += sz_change;
 284         dir_ui->ui_size = dir->i_size;
 285         dir->i_mtime = dir->i_ctime = inode->i_ctime;
 286         err = ubifs_jnl_update(c, dir, &dentry->d_name, inode, 0, 0);
 287         if (err)
 288                 goto out_cancel;
 289         mutex_unlock(&dir_ui->ui_mutex);
 290
 291         ubifs_release_budget(c, &req);
 292         insert_inode_hash(inode);
 293         d_instantiate(dentry, inode);
 294         return 0;
 295
 296 out_cancel:
 297         dir->i_size -= sz_change;
 298         dir_ui->ui_size = dir->i_size;
 299         mutex_unlock(&dir_ui->ui_mutex);
 300         make_bad_inode(inode);
 301         iput(inode);
 302 out_budg:
 303         ubifs_release_budget(c, &req);
 304         ubifs_err("cannot create regular file, error %d", err);
 305         return err;
 306 }
 307
 308 /**
 309  * vfs_dent_type - get VFS directory entry type.
 310  * @type: UBIFS directory entry type
 311  *
 312  * This function converts UBIFS directory entry type into VFS directory entry
 313  * type.
 314  */
 315 static unsigned int vfs_dent_type(uint8_t type)
 316 {
 317         switch (type) {
 318         case UBIFS_ITYPE_REG:
 319                 return DT_REG;
 320         case UBIFS_ITYPE_DIR:
 321                 return DT_DIR;
 322         case UBIFS_ITYPE_LNK:
 323                 return DT_LNK;
 324         case UBIFS_ITYPE_BLK:
 325                 return DT_BLK;
 326         case UBIFS_ITYPE_CHR:
 327                 return DT_CHR;
 328         case UBIFS_ITYPE_FIFO:
 329                 return DT_FIFO;
 330         case UBIFS_ITYPE_SOCK:
 331                 return DT_SOCK;
 332         default:
 333                 BUG();
 334         }
 335         return 0;
 336 }
 337
 338 /*
 339  * The classical Unix view for directory is that it is a linear array of
 340  * (name, inode number) entries. Linux/VFS assumes this model as well.
 341  * Particularly, 'readdir()' call wants us to return a directory entry offset
 342  * which later may be used to continue 'readdir()'ing the directory or to
 343  * 'seek()' to that specific direntry. Obviously UBIFS does not really fit this
 344  * model because directory entries are identified by keys, which may collide.
 345  *
 346  * UBIFS uses directory entry hash value for directory offsets, so
 347  * 'seekdir()'/'telldir()' may not always work because of possible key
 348  * collisions. But UBIFS guarantees that consecutive 'readdir()' calls work
 349  * properly by means of saving full directory entry name in the private field
 350  * of the file description object.
 351  *
 352  * This means that UBIFS cannot support NFS which requires full
 353  * 'seekdir()'/'telldir()' support.
 354  */
 355 static int ubifs_readdir(struct file *file, void *dirent, filldir_t filldir)
 356 {
 357         int err, over = 0;
 358         struct qstr nm;
 359         union ubifs_key key;
 360         struct ubifs_dent_node *dent;
 361         struct inode *dir = file->f_path.dentry->d_inode;
 362         struct ubifs_info *c = dir->i_sb->s_fs_info;
 363
 364         dbg_gen("dir ino %lu, f_pos %#llx", dir->i_ino, file->f_pos);
 365
 366         if (file->f_pos > UBIFS_S_KEY_HASH_MASK || file->f_pos == 2)
 367                 /*
 368                  * The directory was seek'ed to a senseless position or there
 369                  * are no more entries.
 370                  */
 371                 return 0;
 372
 373         /* File positions 0 and 1 correspond to "." and ".." */
 374         if (file->f_pos == 0) {
 375                 ubifs_assert(!file->private_data);
 376                 over = filldir(dirent, ".", 1, 0, dir->i_ino, DT_DIR);
 377                 if (over)
 378                         return 0;
 379                 file->f_pos = 1;
 380         }
 381
 382         if (file->f_pos == 1) {
 383                 ubifs_assert(!file->private_data);
 384                 over = filldir(dirent, "..", 2, 1,
 385                                parent_ino(file->f_path.dentry), DT_DIR);
 386                 if (over)
 387                         return 0;
 388
 389                 /* Find the first entry in TNC and save it */
 390                 lowest_dent_key(c, &key, dir->i_ino);
 391                 nm.name = NULL;
 392                 dent = ubifs_tnc_next_ent(c, &key, &nm);
 393                 if (IS_ERR(dent)) {
 394                         err = PTR_ERR(dent);
 395                         goto out;
 396                 }
 397
 398                 file->f_pos = key_hash_flash(c, &dent->key);
 399                 file->private_data = dent;
 400         }
 401
 402         dent = file->private_data;
 403         if (!dent) {
 404                 /*
 405                  * The directory was seek'ed to and is now readdir'ed.
 406                  * Find the entry corresponding to @file->f_pos or the
 407                  * closest one.
 408                  */
 409                 dent_key_init_hash(c, &key, dir->i_ino, file->f_pos);
 410                 nm.name = NULL;
 411                 dent = ubifs_tnc_next_ent(c, &key, &nm);
 412                 if (IS_ERR(dent)) {
 413                         err = PTR_ERR(dent);
 414                         goto out;
 415                 }
 416                 file->f_pos = key_hash_flash(c, &dent->key);
 417                 file->private_data = dent;
 418         }
 419
 420         while (1) {
 421                 dbg_gen("feed '%s', ino %llu, new f_pos %#x",
 422                         dent->name, (unsigned long long)le64_to_cpu(dent->inum),
 423                         key_hash_flash(c, &dent->key));
 424                 ubifs_assert(le64_to_cpu(dent->ch.sqnum) >
 425                              ubifs_inode(dir)->creat_sqnum);
 426
 427                 nm.len = le16_to_cpu(dent->nlen);
 428                 over = filldir(dirent, dent->name, nm.len, file->f_pos,
 429                                le64_to_cpu(dent->inum),
 430                                vfs_dent_type(dent->type));
 431                 if (over)
 432                         return 0;
 433
 434                 /* Switch to the next entry */
 435                 key_read(c, &dent->key, &key);
 436                 nm.name = dent->name;
 437                 dent = ubifs_tnc_next_ent(c, &key, &nm);
 438                 if (IS_ERR(dent)) {
 439                         err = PTR_ERR(dent);
 440                         goto out;
 441                 }
 442
 443                 kfree(file->private_data);
 444                 file->f_pos = key_hash_flash(c, &dent->key);
 445                 file->private_data = dent;
 446                 cond_resched();
 447         }
 448
 449 out:
 450         if (err != -ENOENT) {
 451                 ubifs_err("cannot find next direntry, error %d", err);
 452                 return err;
 453         }
 454
 455         kfree(file->private_data);
 456         file->private_data = NULL;
 457         file->f_pos = 2;
 458         return 0;
 459 }
 460
 461 /* If a directory is seeked, we have to free saved readdir() state */
 462 static loff_t ubifs_dir_llseek(struct file *file, loff_t offset, int origin)
 463 {
 464         kfree(file->private_data);
 465         file->private_data = NULL;
 466         return generic_file_llseek(file, offset, origin);
 467 }
 468
 469 /* Free saved readdir() state when the directory is closed */
 470 static int ubifs_dir_release(struct inode *dir, struct file *file)
 471 {
 472         kfree(file->private_data);
 473         file->private_data = NULL;
 474         return 0;
 475 }
 476
 477 /**
 478  * lock_2_inodes - a wrapper for locking two UBIFS inodes.
 479  * @inode1: first inode
 480  * @inode2: second inode
 481  *
 482  * We do not implement any tricks to guarantee strict lock ordering, because
 483  * VFS has already done it for us on the @i_mutex. So this is just a simple
 484  * wrapper function.
 485  */
 486 static void lock_2_inodes(struct inode *inode1, struct inode *inode2)
 487 {
 488         mutex_lock_nested(&ubifs_inode(inode1)->ui_mutex, WB_MUTEX_1);
 489         mutex_lock_nested(&ubifs_inode(inode2)->ui_mutex, WB_MUTEX_2);
 490 }
 491
 492 /**
 493  * unlock_2_inodes - a wrapper for unlocking two UBIFS inodes.
 494  * @inode1: first inode
 495  * @inode2: second inode
 496  */
 497 static void unlock_2_inodes(struct inode *inode1, struct inode *inode2)
 498 {
 499         mutex_unlock(&ubifs_inode(inode2)->ui_mutex);
 500         mutex_unlock(&ubifs_inode(inode1)->ui_mutex);
 501 }
 502
 503 static int ubifs_link(struct dentry *old_dentry, struct inode *dir,
 504                       struct dentry *dentry)
 505 {
 506         struct ubifs_info *c = dir->i_sb->s_fs_info;
 507         struct inode *inode = old_dentry->d_inode;
 508         struct ubifs_inode *ui = ubifs_inode(inode);
 509         struct ubifs_inode *dir_ui = ubifs_inode(dir);
 510         int err, sz_change = CALC_DENT_SIZE(dentry->d_name.len);
 511         struct ubifs_budget_req req = { .new_dent = 1, .dirtied_ino = 2,
 512                                 .dirtied_ino_d = ALIGN(ui->data_len, 8) };
 513
 514         /*
 515          * Budget request settings: new direntry, changing the target inode,
 516          * changing the parent inode.
 517          */
 518
 519         dbg_gen("dent '%.*s' to ino %lu (nlink %d) in dir ino %lu",
 520                 dentry->d_name.len, dentry->d_name.name, inode->i_ino,
 521                 inode->i_nlink, dir->i_ino);
 522         ubifs_assert(mutex_is_locked(&dir->i_mutex));
 523         ubifs_assert(mutex_is_locked(&inode->i_mutex));
 524
 525         err = dbg_check_synced_i_size(inode);
 526         if (err)
 527                 return err;
 528
 529         err = ubifs_budget_space(c, &req);
 530         if (err)
 531                 return err;
 532
 533         lock_2_inodes(dir, inode);
 534         inc_nlink(inode);
 535         ihold(inode);
 536         inode->i_ctime = ubifs_current_time(inode);
 537         dir->i_size += sz_change;
 538         dir_ui->ui_size = dir->i_size;
 539         dir->i_mtime = dir->i_ctime = inode->i_ctime;
 540         err = ubifs_jnl_update(c, dir, &dentry->d_name, inode, 0, 0);
 541         if (err)
 542                 goto out_cancel;
 543         unlock_2_inodes(dir, inode);
 544
 545         ubifs_release_budget(c, &req);
 546         d_instantiate(dentry, inode);
 547         return 0;
 548
 549 out_cancel:
 550         dir->i_size -= sz_change;
 551         dir_ui->ui_size = dir->i_size;
 552         drop_nlink(inode);
 553         unlock_2_inodes(dir, inode);
 554         ubifs_release_budget(c, &req);
 555         iput(inode);
 556         return err;
 557 }
 558
 559 static int ubifs_unlink(struct inode *dir, struct dentry *dentry)
 560 {
 561         struct ubifs_info *c = dir->i_sb->s_fs_info;
 562         struct inode *inode = dentry->d_inode;
 563         struct ubifs_inode *dir_ui = ubifs_inode(dir);
 564         int sz_change = CALC_DENT_SIZE(dentry->d_name.len);
 565         int err, budgeted = 1;
 566         struct ubifs_budget_req req = { .mod_dent = 1, .dirtied_ino = 2 };
 567
 568         /*
 569          * Budget request settings: deletion direntry, deletion inode (+1 for
 570          * @dirtied_ino), changing the parent directory inode. If budgeting
 571          * fails, go ahead anyway because we have extra space reserved for
 572          * deletions.
 573          */
 574
 575         dbg_gen("dent '%.*s' from ino %lu (nlink %d) in dir ino %lu",
 576                 dentry->d_name.len, dentry->d_name.name, inode->i_ino,
 577                 inode->i_nlink, dir->i_ino);
 578         ubifs_assert(mutex_is_locked(&dir->i_mutex));
 579         ubifs_assert(mutex_is_locked(&inode->i_mutex));
 580         err = dbg_check_synced_i_size(inode);
 581         if (err)
 582                 return err;
 583
 584         err = ubifs_budget_space(c, &req);
 585         if (err) {
 586                 if (err != -ENOSPC)
 587                         return err;
 588                 budgeted = 0;
 589         }
 590
 591         lock_2_inodes(dir, inode);
 592         inode->i_ctime = ubifs_current_time(dir);
 593         drop_nlink(inode);
 594         dir->i_size -= sz_change;
 595         dir_ui->ui_size = dir->i_size;
 596         dir->i_mtime = dir->i_ctime = inode->i_ctime;
 597         err = ubifs_jnl_update(c, dir, &dentry->d_name, inode, 1, 0);
 598         if (err)
 599                 goto out_cancel;
 600         unlock_2_inodes(dir, inode);
 601
 602         if (budgeted)
 603                 ubifs_release_budget(c, &req);
 604         else {
 605                 /* We've deleted something - clean the "no space" flags */
 606                 c->nospace = c->nospace_rp = 0;
 607                 smp_wmb();
 608         }
 609         return 0;
 610
 611 out_cancel:
 612         dir->i_size += sz_change;
 613         dir_ui->ui_size = dir->i_size;
 614         inc_nlink(inode);
 615         unlock_2_inodes(dir, inode);
 616         if (budgeted)
 617                 ubifs_release_budget(c, &req);
 618         return err;
 619 }
 620
 621 /**
 622  * check_dir_empty - check if a directory is empty or not.
 623  * @c: UBIFS file-system description object
 624  * @dir: VFS inode object of the directory to check
 625  *
 626  * This function checks if directory @dir is empty. Returns zero if the
 627  * directory is empty, %-ENOTEMPTY if it is not, and other negative error codes
 628  * in case of of errors.
 629  */
 630 static int check_dir_empty(struct ubifs_info *c, struct inode *dir)
 631 {
 632         struct qstr nm = { .name = NULL };
 633         struct ubifs_dent_node *dent;
 634         union ubifs_key key;
 635         int err;
 636
 637         lowest_dent_key(c, &key, dir->i_ino);
 638         dent = ubifs_tnc_next_ent(c, &key, &nm);
 639         if (IS_ERR(dent)) {
 640                 err = PTR_ERR(dent);
 641                 if (err == -ENOENT)
 642                         err = 0;
 643         } else {
 644                 kfree(dent);
 645                 err = -ENOTEMPTY;
 646         }
 647         return err;
 648 }
 649
 650 static int ubifs_rmdir(struct inode *dir, struct dentry *dentry)
 651 {
 652         struct ubifs_info *c = dir->i_sb->s_fs_info;
 653         struct inode *inode = dentry->d_inode;
 654         int sz_change = CALC_DENT_SIZE(dentry->d_name.len);
 655         int err, budgeted = 1;
 656         struct ubifs_inode *dir_ui = ubifs_inode(dir);
 657         struct ubifs_budget_req req = { .mod_dent = 1, .dirtied_ino = 2 };
 658
 659         /*
 660          * Budget request settings: deletion direntry, deletion inode and
 661          * changing the parent inode. If budgeting fails, go ahead anyway
 662          * because we have extra space reserved for deletions.
 663          */
 664
 665         dbg_gen("directory '%.*s', ino %lu in dir ino %lu", dentry->d_name.len,
 666                 dentry->d_name.name, inode->i_ino, dir->i_ino);
 667         ubifs_assert(mutex_is_locked(&dir->i_mutex));
 668         ubifs_assert(mutex_is_locked(&inode->i_mutex));
 669         err = check_dir_empty(c, dentry->d_inode);
 670         if (err)
 671                 return err;
 672
 673         err = ubifs_budget_space(c, &req);
 674         if (err) {
 675                 if (err != -ENOSPC)
 676                         return err;
 677                 budgeted = 0;
 678         }
 679
 680         lock_2_inodes(dir, inode);
 681         inode->i_ctime = ubifs_current_time(dir);
 682         clear_nlink(inode);
 683         drop_nlink(dir);
 684         dir->i_size -= sz_change;
 685         dir_ui->ui_size = dir->i_size;
 686         dir->i_mtime = dir->i_ctime = inode->i_ctime;
 687         err = ubifs_jnl_update(c, dir, &dentry->d_name, inode, 1, 0);
 688         if (err)
 689                 goto out_cancel;
 690         unlock_2_inodes(dir, inode);
 691
 692         if (budgeted)
 693                 ubifs_release_budget(c, &req);
 694         else {
 695                 /* We've deleted something - clean the "no space" flags */
 696                 c->nospace = c->nospace_rp = 0;
 697                 smp_wmb();
 698         }
 699         return 0;
 700
 701 out_cancel:
 702         dir->i_size += sz_change;
 703         dir_ui->ui_size = dir->i_size;
 704         inc_nlink(dir);
 705         inc_nlink(inode);
 706         inc_nlink(inode);
 707         unlock_2_inodes(dir, inode);
 708         if (budgeted)
 709                 ubifs_release_budget(c, &req);
 710         return err;
 711 }
 712
 713 static int ubifs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 714 {
 715         struct inode *inode;
 716         struct ubifs_inode *dir_ui = ubifs_inode(dir);
 717         struct ubifs_info *c = dir->i_sb->s_fs_info;
 718         int err, sz_change = CALC_DENT_SIZE(dentry->d_name.len);
 719         struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1 };
 720
 721         /*
 722          * Budget request settings: new inode, new direntry and changing parent
 723          * directory inode.
 724          */
 725
 726         dbg_gen("dent '%.*s', mode %#x in dir ino %lu",
 727                 dentry->d_name.len, dentry->d_name.name, mode, dir->i_ino);
 728
 729         err = ubifs_budget_space(c, &req);
 730         if (err)
 731                 return err;
 732
 733         inode = ubifs_new_inode(c, dir, S_IFDIR | mode);
 734         if (IS_ERR(inode)) {
 735                 err = PTR_ERR(inode);
 736                 goto out_budg;
 737         }
 738
 739         mutex_lock(&dir_ui->ui_mutex);
 740         insert_inode_hash(inode);
 741         inc_nlink(inode);
 742         inc_nlink(dir);
 743         dir->i_size += sz_change;
 744         dir_ui->ui_size = dir->i_size;
 745         dir->i_mtime = dir->i_ctime = inode->i_ctime;
 746         err = ubifs_jnl_update(c, dir, &dentry->d_name, inode, 0, 0);
 747         if (err) {
 748                 ubifs_err("cannot create directory, error %d", err);
 749                 goto out_cancel;
 750         }
 751         mutex_unlock(&dir_ui->ui_mutex);
 752
 753         ubifs_release_budget(c, &req);
 754         d_instantiate(dentry, inode);
 755         return 0;
 756
 757 out_cancel:
 758         dir->i_size -= sz_change;
 759         dir_ui->ui_size = dir->i_size;
 760         drop_nlink(dir);
 761         mutex_unlock(&dir_ui->ui_mutex);
 762         make_bad_inode(inode);
 763         iput(inode);
 764 out_budg:
 765         ubifs_release_budget(c, &req);
 766         return err;
 767 }
 768
 769 static int ubifs_mknod(struct inode *dir, struct dentry *dentry,
 770                        int mode, dev_t rdev)
 771 {
 772         struct inode *inode;
 773         struct ubifs_inode *ui;
 774         struct ubifs_inode *dir_ui = ubifs_inode(dir);
 775         struct ubifs_info *c = dir->i_sb->s_fs_info;
 776         union ubifs_dev_desc *dev = NULL;
 777         int sz_change = CALC_DENT_SIZE(dentry->d_name.len);
 778         int err, devlen = 0;
 779         struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
 780                                         .new_ino_d = ALIGN(devlen, 8),
 781                                         .dirtied_ino = 1 };
 782
 783         /*
 784          * Budget request settings: new inode, new direntry and changing parent
 785          * directory inode.
 786          */
 787
 788         dbg_gen("dent '%.*s' in dir ino %lu",
 789                 dentry->d_name.len, dentry->d_name.name, dir->i_ino);
 790
 791         if (!new_valid_dev(rdev))
 792                 return -EINVAL;
 793
 794         if (S_ISBLK(mode) || S_ISCHR(mode)) {
 795                 dev = kmalloc(sizeof(union ubifs_dev_desc), GFP_NOFS);
 796                 if (!dev)
 797                         return -ENOMEM;
 798                 devlen = ubifs_encode_dev(dev, rdev);
 799         }
 800
 801         err = ubifs_budget_space(c, &req);
 802         if (err) {
 803                 kfree(dev);
 804                 return err;
 805         }
 806
 807         inode = ubifs_new_inode(c, dir, mode);
 808         if (IS_ERR(inode)) {
 809                 kfree(dev);
 810                 err = PTR_ERR(inode);
 811                 goto out_budg;
 812         }
 813
 814         init_special_inode(inode, inode->i_mode, rdev);
 815         inode->i_size = ubifs_inode(inode)->ui_size = devlen;
 816         ui = ubifs_inode(inode);
 817         ui->data = dev;
 818         ui->data_len = devlen;
 819
 820         mutex_lock(&dir_ui->ui_mutex);
 821         dir->i_size += sz_change;
 822         dir_ui->ui_size = dir->i_size;
 823         dir->i_mtime = dir->i_ctime = inode->i_ctime;
 824         err = ubifs_jnl_update(c, dir, &dentry->d_name, inode, 0, 0);
 825         if (err)
 826                 goto out_cancel;
 827         mutex_unlock(&dir_ui->ui_mutex);
 828
 829         ubifs_release_budget(c, &req);
 830         insert_inode_hash(inode);
 831         d_instantiate(dentry, inode);
 832         return 0;
 833
 834 out_cancel:
 835         dir->i_size -= sz_change;
 836         dir_ui->ui_size = dir->i_size;
 837         mutex_unlock(&dir_ui->ui_mutex);
 838         make_bad_inode(inode);
 839         iput(inode);
 840 out_budg:
 841         ubifs_release_budget(c, &req);
 842         return err;
 843 }
 844
 845 static int ubifs_symlink(struct inode *dir, struct dentry *dentry,
 846                          const char *symname)
 847 {
 848         struct inode *inode;
 849         struct ubifs_inode *ui;
 850         struct ubifs_inode *dir_ui = ubifs_inode(dir);
 851         struct ubifs_info *c = dir->i_sb->s_fs_info;
 852         int err, len = strlen(symname);
 853         int sz_change = CALC_DENT_SIZE(dentry->d_name.len);
 854         struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
 855                                         .new_ino_d = ALIGN(len, 8),
 856                                         .dirtied_ino = 1 };
 857
 858         /*
 859          * Budget request settings: new inode, new direntry and changing parent
 860          * directory inode.
 861          */
 862
 863         dbg_gen("dent '%.*s', target '%s' in dir ino %lu", dentry->d_name.len,
 864                 dentry->d_name.name, symname, dir->i_ino);
 865
 866         if (len > UBIFS_MAX_INO_DATA)
 867                 return -ENAMETOOLONG;
 868
 869         err = ubifs_budget_space(c, &req);
 870         if (err)
 871                 return err;
 872
 873         inode = ubifs_new_inode(c, dir, S_IFLNK | S_IRWXUGO);
 874         if (IS_ERR(inode)) {
 875                 err = PTR_ERR(inode);
 876                 goto out_budg;
 877         }
 878
 879         ui = ubifs_inode(inode);
 880         ui->data = kmalloc(len + 1, GFP_NOFS);
 881         if (!ui->data) {
 882                 err = -ENOMEM;
 883                 goto out_inode;
 884         }
 885
 886         memcpy(ui->data, symname, len);
 887         ((char *)ui->data)[len] = '\0';
 888         /*
 889          * The terminating zero byte is not written to the flash media and it
 890          * is put just to make later in-memory string processing simpler. Thus,
 891          * data length is @len, not @len + %1.
 892          */
 893         ui->data_len = len;
 894         inode->i_size = ubifs_inode(inode)->ui_size = len;
 895
 896         mutex_lock(&dir_ui->ui_mutex);
 897         dir->i_size += sz_change;
 898         dir_ui->ui_size = dir->i_size;
 899         dir->i_mtime = dir->i_ctime = inode->i_ctime;
 900         err = ubifs_jnl_update(c, dir, &dentry->d_name, inode, 0, 0);
 901         if (err)
 902                 goto out_cancel;
 903         mutex_unlock(&dir_ui->ui_mutex);
 904
 905         ubifs_release_budget(c, &req);
 906         insert_inode_hash(inode);
 907         d_instantiate(dentry, inode);
 908         return 0;
 909
 910 out_cancel:
 911         dir->i_size -= sz_change;
 912         dir_ui->ui_size = dir->i_size;
 913         mutex_unlock(&dir_ui->ui_mutex);
 914 out_inode:
 915         make_bad_inode(inode);
 916         iput(inode);
 917 out_budg:
 918         ubifs_release_budget(c, &req);
 919         return err;
 920 }
 921
 922 /**
 923  * lock_3_inodes - a wrapper for locking three UBIFS inodes.
 924  * @inode1: first inode
 925  * @inode2: second inode
 926  * @inode3: third inode
 927  *
 928  * This function is used for 'ubifs_rename()' and @inode1 may be the same as
 929  * @inode2 whereas @inode3 may be %NULL.
 930  *
 931  * We do not implement any tricks to guarantee strict lock ordering, because
 932  * VFS has already done it for us on the @i_mutex. So this is just a simple
 933  * wrapper function.
 934  */
 935 static void lock_3_inodes(struct inode *inode1, struct inode *inode2,
 936                           struct inode *inode3)
 937 {
 938         mutex_lock_nested(&ubifs_inode(inode1)->ui_mutex, WB_MUTEX_1);
 939         if (inode2 != inode1)
 940                 mutex_lock_nested(&ubifs_inode(inode2)->ui_mutex, WB_MUTEX_2);
 941         if (inode3)
 942                 mutex_lock_nested(&ubifs_inode(inode3)->ui_mutex, WB_MUTEX_3);
 943 }
 944
 945 /**
 946  * unlock_3_inodes - a wrapper for unlocking three UBIFS inodes for rename.
 947  * @inode1: first inode
 948  * @inode2: second inode
 949  * @inode3: third inode
 950  */
 951 static void unlock_3_inodes(struct inode *inode1, struct inode *inode2,
 952                             struct inode *inode3)
 953 {
 954         if (inode3)
 955                 mutex_unlock(&ubifs_inode(inode3)->ui_mutex);
 956         if (inode1 != inode2)
 957                 mutex_unlock(&ubifs_inode(inode2)->ui_mutex);
 958         mutex_unlock(&ubifs_inode(inode1)->ui_mutex);
 959 }
 960
 961 static int ubifs_rename(struct inode *old_dir, struct dentry *old_dentry,
 962                         struct inode *new_dir, struct dentry *new_dentry)
 963 {
 964         struct ubifs_info *c = old_dir->i_sb->s_fs_info;
 965         struct inode *old_inode = old_dentry->d_inode;
 966         struct inode *new_inode = new_dentry->d_inode;
 967         struct ubifs_inode *old_inode_ui = ubifs_inode(old_inode);
 968         int err, release, sync = 0, move = (new_dir != old_dir);
 969         int is_dir = S_ISDIR(old_inode->i_mode);
 970         int unlink = !!new_inode;
 971         int new_sz = CALC_DENT_SIZE(new_dentry->d_name.len);
 972         int old_sz = CALC_DENT_SIZE(old_dentry->d_name.len);
 973         struct ubifs_budget_req req = { .new_dent = 1, .mod_dent = 1,
 974                                         .dirtied_ino = 3 };
 975         struct ubifs_budget_req ino_req = { .dirtied_ino = 1,
 976                         .dirtied_ino_d = ALIGN(old_inode_ui->data_len, 8) };
 977         struct timespec time;
 978
 979         /*
 980          * Budget request settings: deletion direntry, new direntry, removing
 981          * the old inode, and changing old and new parent directory inodes.
 982          *
 983          * However, this operation also marks the target inode as dirty and
 984          * does not write it, so we allocate budget for the target inode
 985          * separately.
 986          */
 987
 988         dbg_gen("dent '%.*s' ino %lu in dir ino %lu to dent '%.*s' in "
 989                 "dir ino %lu", old_dentry->d_name.len, old_dentry->d_name.name,
 990                 old_inode->i_ino, old_dir->i_ino, new_dentry->d_name.len,
 991                 new_dentry->d_name.name, new_dir->i_ino);
 992         ubifs_assert(mutex_is_locked(&old_dir->i_mutex));
 993         ubifs_assert(mutex_is_locked(&new_dir->i_mutex));
 994         if (unlink)
 995                 ubifs_assert(mutex_is_locked(&new_inode->i_mutex));
 996
 997
 998         if (unlink && is_dir) {
 999                 err = check_dir_empty(c, new_inode);
1000                 if (err)
1001                         return err;
1002         }
1003
1004         err = ubifs_budget_space(c, &req);
1005         if (err)
1006                 return err;
1007         err = ubifs_budget_space(c, &ino_req);
1008         if (err) {
1009                 ubifs_release_budget(c, &req);
1010                 return err;
1011         }
1012
1013         lock_3_inodes(old_dir, new_dir, new_inode);
1014
1015         /*
1016          * Like most other Unix systems, set the @i_ctime for inodes on a
1017          * rename.
1018          */
1019         time = ubifs_current_time(old_dir);
1020         old_inode->i_ctime = time;
1021
1022         /* We must adjust parent link count when renaming directories */
1023         if (is_dir) {
1024                 if (move) {
1025                         /*
1026                          * @old_dir loses a link because we are moving
1027                          * @old_inode to a different directory.
1028                          */
1029                         drop_nlink(old_dir);
1030                         /*
1031                          * @new_dir only gains a link if we are not also
1032                          * overwriting an existing directory.
1033                          */
1034                         if (!unlink)
1035                                 inc_nlink(new_dir);
1036                 } else {
1037                         /*
1038                          * @old_inode is not moving to a different directory,
1039                          * but @old_dir still loses a link if we are
1040                          * overwriting an existing directory.
1041                          */
1042                         if (unlink)
1043                                 drop_nlink(old_dir);
1044                 }
1045         }
1046
1047         old_dir->i_size -= old_sz;
1048         ubifs_inode(old_dir)->ui_size = old_dir->i_size;
1049         old_dir->i_mtime = old_dir->i_ctime = time;
1050         new_dir->i_mtime = new_dir->i_ctime = time;
1051
1052         /*
1053          * And finally, if we unlinked a direntry which happened to have the
1054          * same name as the moved direntry, we have to decrement @i_nlink of
1055          * the unlinked inode and change its ctime.
1056          */
1057         if (unlink) {
1058                 /*
1059                  * Directories cannot have hard-links, so if this is a
1060                  * directory, decrement its @i_nlink twice because an empty
1061                  * directory has @i_nlink 2.
1062                  */
1063                 if (is_dir)
1064                         drop_nlink(new_inode);
1065                 new_inode->i_ctime = time;
1066                 drop_nlink(new_inode);
1067         } else {
1068                 new_dir->i_size += new_sz;
1069                 ubifs_inode(new_dir)->ui_size = new_dir->i_size;
1070         }
1071
1072         /*
1073          * Do not ask 'ubifs_jnl_rename()' to flush write-buffer if @old_inode
1074          * is dirty, because this will be done later on at the end of
1075          * 'ubifs_rename()'.
1076          */
1077         if (IS_SYNC(old_inode)) {
1078                 sync = IS_DIRSYNC(old_dir) || IS_DIRSYNC(new_dir);
1079                 if (unlink && IS_SYNC(new_inode))
1080                         sync = 1;
1081         }
1082         err = ubifs_jnl_rename(c, old_dir, old_dentry, new_dir, new_dentry,
1083                                sync);
1084         if (err)
1085                 goto out_cancel;
1086
1087         unlock_3_inodes(old_dir, new_dir, new_inode);
1088         ubifs_release_budget(c, &req);
1089
1090         mutex_lock(&old_inode_ui->ui_mutex);
1091         release = old_inode_ui->dirty;
1092         mark_inode_dirty_sync(old_inode);
1093         mutex_unlock(&old_inode_ui->ui_mutex);
1094
1095         if (release)
1096                 ubifs_release_budget(c, &ino_req);
1097         if (IS_SYNC(old_inode))
1098                 err = old_inode->i_sb->s_op->write_inode(old_inode, NULL);
1099         return err;
1100
1101 out_cancel:
1102         if (unlink) {
1103                 if (is_dir)
1104                         inc_nlink(new_inode);
1105                 inc_nlink(new_inode);
1106         } else {
1107                 new_dir->i_size -= new_sz;
1108                 ubifs_inode(new_dir)->ui_size = new_dir->i_size;
1109         }
1110         old_dir->i_size += old_sz;
1111         ubifs_inode(old_dir)->ui_size = old_dir->i_size;
1112         if (is_dir) {
1113                 if (move) {
1114                         inc_nlink(old_dir);
1115                         if (!unlink)
1116                                 drop_nlink(new_dir);
1117                 } else {
1118                         if (unlink)
1119                                 inc_nlink(old_dir);
1120                 }
1121         }
1122         unlock_3_inodes(old_dir, new_dir, new_inode);
1123         ubifs_release_budget(c, &ino_req);
1124         ubifs_release_budget(c, &req);
1125         return err;
1126 }
1127
1128 int ubifs_getattr(struct vfsmount *mnt, struct dentry *dentry,
1129                   struct kstat *stat)
1130 {
1131         loff_t size;
1132         struct inode *inode = dentry->d_inode;
1133         struct ubifs_inode *ui = ubifs_inode(inode);
1134
1135         mutex_lock(&ui->ui_mutex);
1136         stat->dev = inode->i_sb->s_dev;
1137         stat->ino = inode->i_ino;
1138         stat->mode = inode->i_mode;
1139         stat->nlink = inode->i_nlink;
1140         stat->uid = inode->i_uid;
1141         stat->gid = inode->i_gid;
1142         stat->rdev = inode->i_rdev;
1143         stat->atime = inode->i_atime;
1144         stat->mtime = inode->i_mtime;
1145         stat->ctime = inode->i_ctime;
1146         stat->blksize = UBIFS_BLOCK_SIZE;
1147         stat->size = ui->ui_size;
1148
1149         /*
1150          * Unfortunately, the 'stat()' system call was designed for block
1151          * device based file systems, and it is not appropriate for UBIFS,
1152          * because UBIFS does not have notion of "block". For example, it is
1153          * difficult to tell how many block a directory takes - it actually
1154          * takes less than 300 bytes, but we have to round it to block size,
1155          * which introduces large mistake. This makes utilities like 'du' to
1156          * report completely senseless numbers. This is the reason why UBIFS
1157          * goes the same way as JFFS2 - it reports zero blocks for everything
1158          * but regular files, which makes more sense than reporting completely
1159          * wrong sizes.
1160          */
1161         if (S_ISREG(inode->i_mode)) {
1162                 size = ui->xattr_size;
1163                 size += stat->size;
1164                 size = ALIGN(size, UBIFS_BLOCK_SIZE);
1165                 /*
1166                  * Note, user-space expects 512-byte blocks count irrespectively
1167                  * of what was reported in @stat->size.
1168                  */
1169                 stat->blocks = size >> 9;
1170         } else
1171                 stat->blocks = 0;
1172         mutex_unlock(&ui->ui_mutex);
1173         return 0;
1174 }
1175
1176 const struct inode_operations ubifs_dir_inode_operations = {
1177         .lookup      = ubifs_lookup,
1178         .create      = ubifs_create,
1179         .link        = ubifs_link,
1180         .symlink     = ubifs_symlink,
1181         .unlink      = ubifs_unlink,
1182         .mkdir       = ubifs_mkdir,
1183         .rmdir       = ubifs_rmdir,
1184         .mknod       = ubifs_mknod,
1185         .rename      = ubifs_rename,
1186         .setattr     = ubifs_setattr,
1187         .getattr     = ubifs_getattr,
1188 #ifdef CONFIG_UBIFS_FS_XATTR
1189         .setxattr    = ubifs_setxattr,
1190         .getxattr    = ubifs_getxattr,
1191         .listxattr   = ubifs_listxattr,
1192         .removexattr = ubifs_removexattr,
1193 #endif
1194 };
1195
1196 const struct file_operations ubifs_dir_operations = {
1197         .llseek         = ubifs_dir_llseek,
1198         .release        = ubifs_dir_release,
1199         .read           = generic_read_dir,
1200         .readdir        = ubifs_readdir,
1201         .fsync          = ubifs_fsync,
1202         .unlocked_ioctl = ubifs_ioctl,
1203 #ifdef CONFIG_COMPAT
1204         .compat_ioctl   = ubifs_compat_ioctl,
1205 #endif
1206 };