xref: /openbmc/linux/fs/ubifs/dir.c (revision 565d76cb)
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 };
1207