xref: /openbmc/linux/fs/ubifs/super.c (revision 249592bf)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * This file is part of UBIFS.
4  *
5  * Copyright (C) 2006-2008 Nokia Corporation.
6  *
7  * Authors: Artem Bityutskiy (Битюцкий Артём)
8  *          Adrian Hunter
9  */
10 
11 /*
12  * This file implements UBIFS initialization and VFS superblock operations. Some
13  * initialization stuff which is rather large and complex is placed at
14  * corresponding subsystems, but most of it is here.
15  */
16 
17 #include <linux/init.h>
18 #include <linux/slab.h>
19 #include <linux/module.h>
20 #include <linux/ctype.h>
21 #include <linux/kthread.h>
22 #include <linux/parser.h>
23 #include <linux/seq_file.h>
24 #include <linux/mount.h>
25 #include <linux/math64.h>
26 #include <linux/writeback.h>
27 #include "ubifs.h"
28 
29 static int ubifs_default_version_set(const char *val, const struct kernel_param *kp)
30 {
31 	int n = 0, ret;
32 
33 	ret = kstrtoint(val, 10, &n);
34 	if (ret != 0 || n < 4 || n > UBIFS_FORMAT_VERSION)
35 		return -EINVAL;
36 	return param_set_int(val, kp);
37 }
38 
39 static const struct kernel_param_ops ubifs_default_version_ops = {
40 	.set = ubifs_default_version_set,
41 	.get = param_get_int,
42 };
43 
44 int ubifs_default_version = UBIFS_FORMAT_VERSION;
45 module_param_cb(default_version, &ubifs_default_version_ops, &ubifs_default_version, 0600);
46 
47 /*
48  * Maximum amount of memory we may 'kmalloc()' without worrying that we are
49  * allocating too much.
50  */
51 #define UBIFS_KMALLOC_OK (128*1024)
52 
53 /* Slab cache for UBIFS inodes */
54 static struct kmem_cache *ubifs_inode_slab;
55 
56 /* UBIFS TNC shrinker description */
57 static struct shrinker ubifs_shrinker_info = {
58 	.scan_objects = ubifs_shrink_scan,
59 	.count_objects = ubifs_shrink_count,
60 	.seeks = DEFAULT_SEEKS,
61 };
62 
63 /**
64  * validate_inode - validate inode.
65  * @c: UBIFS file-system description object
66  * @inode: the inode to validate
67  *
68  * This is a helper function for 'ubifs_iget()' which validates various fields
69  * of a newly built inode to make sure they contain sane values and prevent
70  * possible vulnerabilities. Returns zero if the inode is all right and
71  * a non-zero error code if not.
72  */
73 static int validate_inode(struct ubifs_info *c, const struct inode *inode)
74 {
75 	int err;
76 	const struct ubifs_inode *ui = ubifs_inode(inode);
77 
78 	if (inode->i_size > c->max_inode_sz) {
79 		ubifs_err(c, "inode is too large (%lld)",
80 			  (long long)inode->i_size);
81 		return 1;
82 	}
83 
84 	if (ui->compr_type >= UBIFS_COMPR_TYPES_CNT) {
85 		ubifs_err(c, "unknown compression type %d", ui->compr_type);
86 		return 2;
87 	}
88 
89 	if (ui->xattr_names + ui->xattr_cnt > XATTR_LIST_MAX)
90 		return 3;
91 
92 	if (ui->data_len < 0 || ui->data_len > UBIFS_MAX_INO_DATA)
93 		return 4;
94 
95 	if (ui->xattr && !S_ISREG(inode->i_mode))
96 		return 5;
97 
98 	if (!ubifs_compr_present(c, ui->compr_type)) {
99 		ubifs_warn(c, "inode %lu uses '%s' compression, but it was not compiled in",
100 			   inode->i_ino, ubifs_compr_name(c, ui->compr_type));
101 	}
102 
103 	err = dbg_check_dir(c, inode);
104 	return err;
105 }
106 
107 struct inode *ubifs_iget(struct super_block *sb, unsigned long inum)
108 {
109 	int err;
110 	union ubifs_key key;
111 	struct ubifs_ino_node *ino;
112 	struct ubifs_info *c = sb->s_fs_info;
113 	struct inode *inode;
114 	struct ubifs_inode *ui;
115 
116 	dbg_gen("inode %lu", inum);
117 
118 	inode = iget_locked(sb, inum);
119 	if (!inode)
120 		return ERR_PTR(-ENOMEM);
121 	if (!(inode->i_state & I_NEW))
122 		return inode;
123 	ui = ubifs_inode(inode);
124 
125 	ino = kmalloc(UBIFS_MAX_INO_NODE_SZ, GFP_NOFS);
126 	if (!ino) {
127 		err = -ENOMEM;
128 		goto out;
129 	}
130 
131 	ino_key_init(c, &key, inode->i_ino);
132 
133 	err = ubifs_tnc_lookup(c, &key, ino);
134 	if (err)
135 		goto out_ino;
136 
137 	inode->i_flags |= S_NOCMTIME;
138 
139 	if (!IS_ENABLED(CONFIG_UBIFS_ATIME_SUPPORT))
140 		inode->i_flags |= S_NOATIME;
141 
142 	set_nlink(inode, le32_to_cpu(ino->nlink));
143 	i_uid_write(inode, le32_to_cpu(ino->uid));
144 	i_gid_write(inode, le32_to_cpu(ino->gid));
145 	inode->i_atime.tv_sec  = (int64_t)le64_to_cpu(ino->atime_sec);
146 	inode->i_atime.tv_nsec = le32_to_cpu(ino->atime_nsec);
147 	inode->i_mtime.tv_sec  = (int64_t)le64_to_cpu(ino->mtime_sec);
148 	inode->i_mtime.tv_nsec = le32_to_cpu(ino->mtime_nsec);
149 	inode->i_ctime.tv_sec  = (int64_t)le64_to_cpu(ino->ctime_sec);
150 	inode->i_ctime.tv_nsec = le32_to_cpu(ino->ctime_nsec);
151 	inode->i_mode = le32_to_cpu(ino->mode);
152 	inode->i_size = le64_to_cpu(ino->size);
153 
154 	ui->data_len    = le32_to_cpu(ino->data_len);
155 	ui->flags       = le32_to_cpu(ino->flags);
156 	ui->compr_type  = le16_to_cpu(ino->compr_type);
157 	ui->creat_sqnum = le64_to_cpu(ino->creat_sqnum);
158 	ui->xattr_cnt   = le32_to_cpu(ino->xattr_cnt);
159 	ui->xattr_size  = le32_to_cpu(ino->xattr_size);
160 	ui->xattr_names = le32_to_cpu(ino->xattr_names);
161 	ui->synced_i_size = ui->ui_size = inode->i_size;
162 
163 	ui->xattr = (ui->flags & UBIFS_XATTR_FL) ? 1 : 0;
164 
165 	err = validate_inode(c, inode);
166 	if (err)
167 		goto out_invalid;
168 
169 	switch (inode->i_mode & S_IFMT) {
170 	case S_IFREG:
171 		inode->i_mapping->a_ops = &ubifs_file_address_operations;
172 		inode->i_op = &ubifs_file_inode_operations;
173 		inode->i_fop = &ubifs_file_operations;
174 		if (ui->xattr) {
175 			ui->data = kmalloc(ui->data_len + 1, GFP_NOFS);
176 			if (!ui->data) {
177 				err = -ENOMEM;
178 				goto out_ino;
179 			}
180 			memcpy(ui->data, ino->data, ui->data_len);
181 			((char *)ui->data)[ui->data_len] = '\0';
182 		} else if (ui->data_len != 0) {
183 			err = 10;
184 			goto out_invalid;
185 		}
186 		break;
187 	case S_IFDIR:
188 		inode->i_op  = &ubifs_dir_inode_operations;
189 		inode->i_fop = &ubifs_dir_operations;
190 		if (ui->data_len != 0) {
191 			err = 11;
192 			goto out_invalid;
193 		}
194 		break;
195 	case S_IFLNK:
196 		inode->i_op = &ubifs_symlink_inode_operations;
197 		if (ui->data_len <= 0 || ui->data_len > UBIFS_MAX_INO_DATA) {
198 			err = 12;
199 			goto out_invalid;
200 		}
201 		ui->data = kmalloc(ui->data_len + 1, GFP_NOFS);
202 		if (!ui->data) {
203 			err = -ENOMEM;
204 			goto out_ino;
205 		}
206 		memcpy(ui->data, ino->data, ui->data_len);
207 		((char *)ui->data)[ui->data_len] = '\0';
208 		break;
209 	case S_IFBLK:
210 	case S_IFCHR:
211 	{
212 		dev_t rdev;
213 		union ubifs_dev_desc *dev;
214 
215 		ui->data = kmalloc(sizeof(union ubifs_dev_desc), GFP_NOFS);
216 		if (!ui->data) {
217 			err = -ENOMEM;
218 			goto out_ino;
219 		}
220 
221 		dev = (union ubifs_dev_desc *)ino->data;
222 		if (ui->data_len == sizeof(dev->new))
223 			rdev = new_decode_dev(le32_to_cpu(dev->new));
224 		else if (ui->data_len == sizeof(dev->huge))
225 			rdev = huge_decode_dev(le64_to_cpu(dev->huge));
226 		else {
227 			err = 13;
228 			goto out_invalid;
229 		}
230 		memcpy(ui->data, ino->data, ui->data_len);
231 		inode->i_op = &ubifs_file_inode_operations;
232 		init_special_inode(inode, inode->i_mode, rdev);
233 		break;
234 	}
235 	case S_IFSOCK:
236 	case S_IFIFO:
237 		inode->i_op = &ubifs_file_inode_operations;
238 		init_special_inode(inode, inode->i_mode, 0);
239 		if (ui->data_len != 0) {
240 			err = 14;
241 			goto out_invalid;
242 		}
243 		break;
244 	default:
245 		err = 15;
246 		goto out_invalid;
247 	}
248 
249 	kfree(ino);
250 	ubifs_set_inode_flags(inode);
251 	unlock_new_inode(inode);
252 	return inode;
253 
254 out_invalid:
255 	ubifs_err(c, "inode %lu validation failed, error %d", inode->i_ino, err);
256 	ubifs_dump_node(c, ino, UBIFS_MAX_INO_NODE_SZ);
257 	ubifs_dump_inode(c, inode);
258 	err = -EINVAL;
259 out_ino:
260 	kfree(ino);
261 out:
262 	ubifs_err(c, "failed to read inode %lu, error %d", inode->i_ino, err);
263 	iget_failed(inode);
264 	return ERR_PTR(err);
265 }
266 
267 static struct inode *ubifs_alloc_inode(struct super_block *sb)
268 {
269 	struct ubifs_inode *ui;
270 
271 	ui = kmem_cache_alloc(ubifs_inode_slab, GFP_NOFS);
272 	if (!ui)
273 		return NULL;
274 
275 	memset((void *)ui + sizeof(struct inode), 0,
276 	       sizeof(struct ubifs_inode) - sizeof(struct inode));
277 	mutex_init(&ui->ui_mutex);
278 	spin_lock_init(&ui->ui_lock);
279 	return &ui->vfs_inode;
280 };
281 
282 static void ubifs_free_inode(struct inode *inode)
283 {
284 	struct ubifs_inode *ui = ubifs_inode(inode);
285 
286 	kfree(ui->data);
287 	fscrypt_free_inode(inode);
288 
289 	kmem_cache_free(ubifs_inode_slab, ui);
290 }
291 
292 /*
293  * Note, Linux write-back code calls this without 'i_mutex'.
294  */
295 static int ubifs_write_inode(struct inode *inode, struct writeback_control *wbc)
296 {
297 	int err = 0;
298 	struct ubifs_info *c = inode->i_sb->s_fs_info;
299 	struct ubifs_inode *ui = ubifs_inode(inode);
300 
301 	ubifs_assert(c, !ui->xattr);
302 	if (is_bad_inode(inode))
303 		return 0;
304 
305 	mutex_lock(&ui->ui_mutex);
306 	/*
307 	 * Due to races between write-back forced by budgeting
308 	 * (see 'sync_some_inodes()') and background write-back, the inode may
309 	 * have already been synchronized, do not do this again. This might
310 	 * also happen if it was synchronized in an VFS operation, e.g.
311 	 * 'ubifs_link()'.
312 	 */
313 	if (!ui->dirty) {
314 		mutex_unlock(&ui->ui_mutex);
315 		return 0;
316 	}
317 
318 	/*
319 	 * As an optimization, do not write orphan inodes to the media just
320 	 * because this is not needed.
321 	 */
322 	dbg_gen("inode %lu, mode %#x, nlink %u",
323 		inode->i_ino, (int)inode->i_mode, inode->i_nlink);
324 	if (inode->i_nlink) {
325 		err = ubifs_jnl_write_inode(c, inode);
326 		if (err)
327 			ubifs_err(c, "can't write inode %lu, error %d",
328 				  inode->i_ino, err);
329 		else
330 			err = dbg_check_inode_size(c, inode, ui->ui_size);
331 	}
332 
333 	ui->dirty = 0;
334 	mutex_unlock(&ui->ui_mutex);
335 	ubifs_release_dirty_inode_budget(c, ui);
336 	return err;
337 }
338 
339 static int ubifs_drop_inode(struct inode *inode)
340 {
341 	int drop = generic_drop_inode(inode);
342 
343 	if (!drop)
344 		drop = fscrypt_drop_inode(inode);
345 
346 	return drop;
347 }
348 
349 static void ubifs_evict_inode(struct inode *inode)
350 {
351 	int err;
352 	struct ubifs_info *c = inode->i_sb->s_fs_info;
353 	struct ubifs_inode *ui = ubifs_inode(inode);
354 
355 	if (ui->xattr)
356 		/*
357 		 * Extended attribute inode deletions are fully handled in
358 		 * 'ubifs_removexattr()'. These inodes are special and have
359 		 * limited usage, so there is nothing to do here.
360 		 */
361 		goto out;
362 
363 	dbg_gen("inode %lu, mode %#x", inode->i_ino, (int)inode->i_mode);
364 	ubifs_assert(c, !atomic_read(&inode->i_count));
365 
366 	truncate_inode_pages_final(&inode->i_data);
367 
368 	if (inode->i_nlink)
369 		goto done;
370 
371 	if (is_bad_inode(inode))
372 		goto out;
373 
374 	ui->ui_size = inode->i_size = 0;
375 	err = ubifs_jnl_delete_inode(c, inode);
376 	if (err)
377 		/*
378 		 * Worst case we have a lost orphan inode wasting space, so a
379 		 * simple error message is OK here.
380 		 */
381 		ubifs_err(c, "can't delete inode %lu, error %d",
382 			  inode->i_ino, err);
383 
384 out:
385 	if (ui->dirty)
386 		ubifs_release_dirty_inode_budget(c, ui);
387 	else {
388 		/* We've deleted something - clean the "no space" flags */
389 		c->bi.nospace = c->bi.nospace_rp = 0;
390 		smp_wmb();
391 	}
392 done:
393 	clear_inode(inode);
394 	fscrypt_put_encryption_info(inode);
395 }
396 
397 static void ubifs_dirty_inode(struct inode *inode, int flags)
398 {
399 	struct ubifs_info *c = inode->i_sb->s_fs_info;
400 	struct ubifs_inode *ui = ubifs_inode(inode);
401 
402 	ubifs_assert(c, mutex_is_locked(&ui->ui_mutex));
403 	if (!ui->dirty) {
404 		ui->dirty = 1;
405 		dbg_gen("inode %lu",  inode->i_ino);
406 	}
407 }
408 
409 static int ubifs_statfs(struct dentry *dentry, struct kstatfs *buf)
410 {
411 	struct ubifs_info *c = dentry->d_sb->s_fs_info;
412 	unsigned long long free;
413 	__le32 *uuid = (__le32 *)c->uuid;
414 
415 	free = ubifs_get_free_space(c);
416 	dbg_gen("free space %lld bytes (%lld blocks)",
417 		free, free >> UBIFS_BLOCK_SHIFT);
418 
419 	buf->f_type = UBIFS_SUPER_MAGIC;
420 	buf->f_bsize = UBIFS_BLOCK_SIZE;
421 	buf->f_blocks = c->block_cnt;
422 	buf->f_bfree = free >> UBIFS_BLOCK_SHIFT;
423 	if (free > c->report_rp_size)
424 		buf->f_bavail = (free - c->report_rp_size) >> UBIFS_BLOCK_SHIFT;
425 	else
426 		buf->f_bavail = 0;
427 	buf->f_files = 0;
428 	buf->f_ffree = 0;
429 	buf->f_namelen = UBIFS_MAX_NLEN;
430 	buf->f_fsid.val[0] = le32_to_cpu(uuid[0]) ^ le32_to_cpu(uuid[2]);
431 	buf->f_fsid.val[1] = le32_to_cpu(uuid[1]) ^ le32_to_cpu(uuid[3]);
432 	ubifs_assert(c, buf->f_bfree <= c->block_cnt);
433 	return 0;
434 }
435 
436 static int ubifs_show_options(struct seq_file *s, struct dentry *root)
437 {
438 	struct ubifs_info *c = root->d_sb->s_fs_info;
439 
440 	if (c->mount_opts.unmount_mode == 2)
441 		seq_puts(s, ",fast_unmount");
442 	else if (c->mount_opts.unmount_mode == 1)
443 		seq_puts(s, ",norm_unmount");
444 
445 	if (c->mount_opts.bulk_read == 2)
446 		seq_puts(s, ",bulk_read");
447 	else if (c->mount_opts.bulk_read == 1)
448 		seq_puts(s, ",no_bulk_read");
449 
450 	if (c->mount_opts.chk_data_crc == 2)
451 		seq_puts(s, ",chk_data_crc");
452 	else if (c->mount_opts.chk_data_crc == 1)
453 		seq_puts(s, ",no_chk_data_crc");
454 
455 	if (c->mount_opts.override_compr) {
456 		seq_printf(s, ",compr=%s",
457 			   ubifs_compr_name(c, c->mount_opts.compr_type));
458 	}
459 
460 	seq_printf(s, ",assert=%s", ubifs_assert_action_name(c));
461 	seq_printf(s, ",ubi=%d,vol=%d", c->vi.ubi_num, c->vi.vol_id);
462 
463 	return 0;
464 }
465 
466 static int ubifs_sync_fs(struct super_block *sb, int wait)
467 {
468 	int i, err;
469 	struct ubifs_info *c = sb->s_fs_info;
470 
471 	/*
472 	 * Zero @wait is just an advisory thing to help the file system shove
473 	 * lots of data into the queues, and there will be the second
474 	 * '->sync_fs()' call, with non-zero @wait.
475 	 */
476 	if (!wait)
477 		return 0;
478 
479 	/*
480 	 * Synchronize write buffers, because 'ubifs_run_commit()' does not
481 	 * do this if it waits for an already running commit.
482 	 */
483 	for (i = 0; i < c->jhead_cnt; i++) {
484 		err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
485 		if (err)
486 			return err;
487 	}
488 
489 	/*
490 	 * Strictly speaking, it is not necessary to commit the journal here,
491 	 * synchronizing write-buffers would be enough. But committing makes
492 	 * UBIFS free space predictions much more accurate, so we want to let
493 	 * the user be able to get more accurate results of 'statfs()' after
494 	 * they synchronize the file system.
495 	 */
496 	err = ubifs_run_commit(c);
497 	if (err)
498 		return err;
499 
500 	return ubi_sync(c->vi.ubi_num);
501 }
502 
503 /**
504  * init_constants_early - initialize UBIFS constants.
505  * @c: UBIFS file-system description object
506  *
507  * This function initialize UBIFS constants which do not need the superblock to
508  * be read. It also checks that the UBI volume satisfies basic UBIFS
509  * requirements. Returns zero in case of success and a negative error code in
510  * case of failure.
511  */
512 static int init_constants_early(struct ubifs_info *c)
513 {
514 	if (c->vi.corrupted) {
515 		ubifs_warn(c, "UBI volume is corrupted - read-only mode");
516 		c->ro_media = 1;
517 	}
518 
519 	if (c->di.ro_mode) {
520 		ubifs_msg(c, "read-only UBI device");
521 		c->ro_media = 1;
522 	}
523 
524 	if (c->vi.vol_type == UBI_STATIC_VOLUME) {
525 		ubifs_msg(c, "static UBI volume - read-only mode");
526 		c->ro_media = 1;
527 	}
528 
529 	c->leb_cnt = c->vi.size;
530 	c->leb_size = c->vi.usable_leb_size;
531 	c->leb_start = c->di.leb_start;
532 	c->half_leb_size = c->leb_size / 2;
533 	c->min_io_size = c->di.min_io_size;
534 	c->min_io_shift = fls(c->min_io_size) - 1;
535 	c->max_write_size = c->di.max_write_size;
536 	c->max_write_shift = fls(c->max_write_size) - 1;
537 
538 	if (c->leb_size < UBIFS_MIN_LEB_SZ) {
539 		ubifs_errc(c, "too small LEBs (%d bytes), min. is %d bytes",
540 			   c->leb_size, UBIFS_MIN_LEB_SZ);
541 		return -EINVAL;
542 	}
543 
544 	if (c->leb_cnt < UBIFS_MIN_LEB_CNT) {
545 		ubifs_errc(c, "too few LEBs (%d), min. is %d",
546 			   c->leb_cnt, UBIFS_MIN_LEB_CNT);
547 		return -EINVAL;
548 	}
549 
550 	if (!is_power_of_2(c->min_io_size)) {
551 		ubifs_errc(c, "bad min. I/O size %d", c->min_io_size);
552 		return -EINVAL;
553 	}
554 
555 	/*
556 	 * Maximum write size has to be greater or equivalent to min. I/O
557 	 * size, and be multiple of min. I/O size.
558 	 */
559 	if (c->max_write_size < c->min_io_size ||
560 	    c->max_write_size % c->min_io_size ||
561 	    !is_power_of_2(c->max_write_size)) {
562 		ubifs_errc(c, "bad write buffer size %d for %d min. I/O unit",
563 			   c->max_write_size, c->min_io_size);
564 		return -EINVAL;
565 	}
566 
567 	/*
568 	 * UBIFS aligns all node to 8-byte boundary, so to make function in
569 	 * io.c simpler, assume minimum I/O unit size to be 8 bytes if it is
570 	 * less than 8.
571 	 */
572 	if (c->min_io_size < 8) {
573 		c->min_io_size = 8;
574 		c->min_io_shift = 3;
575 		if (c->max_write_size < c->min_io_size) {
576 			c->max_write_size = c->min_io_size;
577 			c->max_write_shift = c->min_io_shift;
578 		}
579 	}
580 
581 	c->ref_node_alsz = ALIGN(UBIFS_REF_NODE_SZ, c->min_io_size);
582 	c->mst_node_alsz = ALIGN(UBIFS_MST_NODE_SZ, c->min_io_size);
583 
584 	/*
585 	 * Initialize node length ranges which are mostly needed for node
586 	 * length validation.
587 	 */
588 	c->ranges[UBIFS_PAD_NODE].len  = UBIFS_PAD_NODE_SZ;
589 	c->ranges[UBIFS_SB_NODE].len   = UBIFS_SB_NODE_SZ;
590 	c->ranges[UBIFS_MST_NODE].len  = UBIFS_MST_NODE_SZ;
591 	c->ranges[UBIFS_REF_NODE].len  = UBIFS_REF_NODE_SZ;
592 	c->ranges[UBIFS_TRUN_NODE].len = UBIFS_TRUN_NODE_SZ;
593 	c->ranges[UBIFS_CS_NODE].len   = UBIFS_CS_NODE_SZ;
594 	c->ranges[UBIFS_AUTH_NODE].min_len = UBIFS_AUTH_NODE_SZ;
595 	c->ranges[UBIFS_AUTH_NODE].max_len = UBIFS_AUTH_NODE_SZ +
596 				UBIFS_MAX_HMAC_LEN;
597 	c->ranges[UBIFS_SIG_NODE].min_len = UBIFS_SIG_NODE_SZ;
598 	c->ranges[UBIFS_SIG_NODE].max_len = c->leb_size - UBIFS_SB_NODE_SZ;
599 
600 	c->ranges[UBIFS_INO_NODE].min_len  = UBIFS_INO_NODE_SZ;
601 	c->ranges[UBIFS_INO_NODE].max_len  = UBIFS_MAX_INO_NODE_SZ;
602 	c->ranges[UBIFS_ORPH_NODE].min_len =
603 				UBIFS_ORPH_NODE_SZ + sizeof(__le64);
604 	c->ranges[UBIFS_ORPH_NODE].max_len = c->leb_size;
605 	c->ranges[UBIFS_DENT_NODE].min_len = UBIFS_DENT_NODE_SZ;
606 	c->ranges[UBIFS_DENT_NODE].max_len = UBIFS_MAX_DENT_NODE_SZ;
607 	c->ranges[UBIFS_XENT_NODE].min_len = UBIFS_XENT_NODE_SZ;
608 	c->ranges[UBIFS_XENT_NODE].max_len = UBIFS_MAX_XENT_NODE_SZ;
609 	c->ranges[UBIFS_DATA_NODE].min_len = UBIFS_DATA_NODE_SZ;
610 	c->ranges[UBIFS_DATA_NODE].max_len = UBIFS_MAX_DATA_NODE_SZ;
611 	/*
612 	 * Minimum indexing node size is amended later when superblock is
613 	 * read and the key length is known.
614 	 */
615 	c->ranges[UBIFS_IDX_NODE].min_len = UBIFS_IDX_NODE_SZ + UBIFS_BRANCH_SZ;
616 	/*
617 	 * Maximum indexing node size is amended later when superblock is
618 	 * read and the fanout is known.
619 	 */
620 	c->ranges[UBIFS_IDX_NODE].max_len = INT_MAX;
621 
622 	/*
623 	 * Initialize dead and dark LEB space watermarks. See gc.c for comments
624 	 * about these values.
625 	 */
626 	c->dead_wm = ALIGN(MIN_WRITE_SZ, c->min_io_size);
627 	c->dark_wm = ALIGN(UBIFS_MAX_NODE_SZ, c->min_io_size);
628 
629 	/*
630 	 * Calculate how many bytes would be wasted at the end of LEB if it was
631 	 * fully filled with data nodes of maximum size. This is used in
632 	 * calculations when reporting free space.
633 	 */
634 	c->leb_overhead = c->leb_size % UBIFS_MAX_DATA_NODE_SZ;
635 
636 	/* Buffer size for bulk-reads */
637 	c->max_bu_buf_len = UBIFS_MAX_BULK_READ * UBIFS_MAX_DATA_NODE_SZ;
638 	if (c->max_bu_buf_len > c->leb_size)
639 		c->max_bu_buf_len = c->leb_size;
640 
641 	/* Log is ready, preserve one LEB for commits. */
642 	c->min_log_bytes = c->leb_size;
643 
644 	return 0;
645 }
646 
647 /**
648  * bud_wbuf_callback - bud LEB write-buffer synchronization call-back.
649  * @c: UBIFS file-system description object
650  * @lnum: LEB the write-buffer was synchronized to
651  * @free: how many free bytes left in this LEB
652  * @pad: how many bytes were padded
653  *
654  * This is a callback function which is called by the I/O unit when the
655  * write-buffer is synchronized. We need this to correctly maintain space
656  * accounting in bud logical eraseblocks. This function returns zero in case of
657  * success and a negative error code in case of failure.
658  *
659  * This function actually belongs to the journal, but we keep it here because
660  * we want to keep it static.
661  */
662 static int bud_wbuf_callback(struct ubifs_info *c, int lnum, int free, int pad)
663 {
664 	return ubifs_update_one_lp(c, lnum, free, pad, 0, 0);
665 }
666 
667 /*
668  * init_constants_sb - initialize UBIFS constants.
669  * @c: UBIFS file-system description object
670  *
671  * This is a helper function which initializes various UBIFS constants after
672  * the superblock has been read. It also checks various UBIFS parameters and
673  * makes sure they are all right. Returns zero in case of success and a
674  * negative error code in case of failure.
675  */
676 static int init_constants_sb(struct ubifs_info *c)
677 {
678 	int tmp, err;
679 	long long tmp64;
680 
681 	c->main_bytes = (long long)c->main_lebs * c->leb_size;
682 	c->max_znode_sz = sizeof(struct ubifs_znode) +
683 				c->fanout * sizeof(struct ubifs_zbranch);
684 
685 	tmp = ubifs_idx_node_sz(c, 1);
686 	c->ranges[UBIFS_IDX_NODE].min_len = tmp;
687 	c->min_idx_node_sz = ALIGN(tmp, 8);
688 
689 	tmp = ubifs_idx_node_sz(c, c->fanout);
690 	c->ranges[UBIFS_IDX_NODE].max_len = tmp;
691 	c->max_idx_node_sz = ALIGN(tmp, 8);
692 
693 	/* Make sure LEB size is large enough to fit full commit */
694 	tmp = UBIFS_CS_NODE_SZ + UBIFS_REF_NODE_SZ * c->jhead_cnt;
695 	tmp = ALIGN(tmp, c->min_io_size);
696 	if (tmp > c->leb_size) {
697 		ubifs_err(c, "too small LEB size %d, at least %d needed",
698 			  c->leb_size, tmp);
699 		return -EINVAL;
700 	}
701 
702 	/*
703 	 * Make sure that the log is large enough to fit reference nodes for
704 	 * all buds plus one reserved LEB.
705 	 */
706 	tmp64 = c->max_bud_bytes + c->leb_size - 1;
707 	c->max_bud_cnt = div_u64(tmp64, c->leb_size);
708 	tmp = (c->ref_node_alsz * c->max_bud_cnt + c->leb_size - 1);
709 	tmp /= c->leb_size;
710 	tmp += 1;
711 	if (c->log_lebs < tmp) {
712 		ubifs_err(c, "too small log %d LEBs, required min. %d LEBs",
713 			  c->log_lebs, tmp);
714 		return -EINVAL;
715 	}
716 
717 	/*
718 	 * When budgeting we assume worst-case scenarios when the pages are not
719 	 * be compressed and direntries are of the maximum size.
720 	 *
721 	 * Note, data, which may be stored in inodes is budgeted separately, so
722 	 * it is not included into 'c->bi.inode_budget'.
723 	 */
724 	c->bi.page_budget = UBIFS_MAX_DATA_NODE_SZ * UBIFS_BLOCKS_PER_PAGE;
725 	c->bi.inode_budget = UBIFS_INO_NODE_SZ;
726 	c->bi.dent_budget = UBIFS_MAX_DENT_NODE_SZ;
727 
728 	/*
729 	 * When the amount of flash space used by buds becomes
730 	 * 'c->max_bud_bytes', UBIFS just blocks all writers and starts commit.
731 	 * The writers are unblocked when the commit is finished. To avoid
732 	 * writers to be blocked UBIFS initiates background commit in advance,
733 	 * when number of bud bytes becomes above the limit defined below.
734 	 */
735 	c->bg_bud_bytes = (c->max_bud_bytes * 13) >> 4;
736 
737 	/*
738 	 * Ensure minimum journal size. All the bytes in the journal heads are
739 	 * considered to be used, when calculating the current journal usage.
740 	 * Consequently, if the journal is too small, UBIFS will treat it as
741 	 * always full.
742 	 */
743 	tmp64 = (long long)(c->jhead_cnt + 1) * c->leb_size + 1;
744 	if (c->bg_bud_bytes < tmp64)
745 		c->bg_bud_bytes = tmp64;
746 	if (c->max_bud_bytes < tmp64 + c->leb_size)
747 		c->max_bud_bytes = tmp64 + c->leb_size;
748 
749 	err = ubifs_calc_lpt_geom(c);
750 	if (err)
751 		return err;
752 
753 	/* Initialize effective LEB size used in budgeting calculations */
754 	c->idx_leb_size = c->leb_size - c->max_idx_node_sz;
755 	return 0;
756 }
757 
758 /*
759  * init_constants_master - initialize UBIFS constants.
760  * @c: UBIFS file-system description object
761  *
762  * This is a helper function which initializes various UBIFS constants after
763  * the master node has been read. It also checks various UBIFS parameters and
764  * makes sure they are all right.
765  */
766 static void init_constants_master(struct ubifs_info *c)
767 {
768 	long long tmp64;
769 
770 	c->bi.min_idx_lebs = ubifs_calc_min_idx_lebs(c);
771 	c->report_rp_size = ubifs_reported_space(c, c->rp_size);
772 
773 	/*
774 	 * Calculate total amount of FS blocks. This number is not used
775 	 * internally because it does not make much sense for UBIFS, but it is
776 	 * necessary to report something for the 'statfs()' call.
777 	 *
778 	 * Subtract the LEB reserved for GC, the LEB which is reserved for
779 	 * deletions, minimum LEBs for the index, and assume only one journal
780 	 * head is available.
781 	 */
782 	tmp64 = c->main_lebs - 1 - 1 - MIN_INDEX_LEBS - c->jhead_cnt + 1;
783 	tmp64 *= (long long)c->leb_size - c->leb_overhead;
784 	tmp64 = ubifs_reported_space(c, tmp64);
785 	c->block_cnt = tmp64 >> UBIFS_BLOCK_SHIFT;
786 }
787 
788 /**
789  * take_gc_lnum - reserve GC LEB.
790  * @c: UBIFS file-system description object
791  *
792  * This function ensures that the LEB reserved for garbage collection is marked
793  * as "taken" in lprops. We also have to set free space to LEB size and dirty
794  * space to zero, because lprops may contain out-of-date information if the
795  * file-system was un-mounted before it has been committed. This function
796  * returns zero in case of success and a negative error code in case of
797  * failure.
798  */
799 static int take_gc_lnum(struct ubifs_info *c)
800 {
801 	int err;
802 
803 	if (c->gc_lnum == -1) {
804 		ubifs_err(c, "no LEB for GC");
805 		return -EINVAL;
806 	}
807 
808 	/* And we have to tell lprops that this LEB is taken */
809 	err = ubifs_change_one_lp(c, c->gc_lnum, c->leb_size, 0,
810 				  LPROPS_TAKEN, 0, 0);
811 	return err;
812 }
813 
814 /**
815  * alloc_wbufs - allocate write-buffers.
816  * @c: UBIFS file-system description object
817  *
818  * This helper function allocates and initializes UBIFS write-buffers. Returns
819  * zero in case of success and %-ENOMEM in case of failure.
820  */
821 static int alloc_wbufs(struct ubifs_info *c)
822 {
823 	int i, err;
824 
825 	c->jheads = kcalloc(c->jhead_cnt, sizeof(struct ubifs_jhead),
826 			    GFP_KERNEL);
827 	if (!c->jheads)
828 		return -ENOMEM;
829 
830 	/* Initialize journal heads */
831 	for (i = 0; i < c->jhead_cnt; i++) {
832 		INIT_LIST_HEAD(&c->jheads[i].buds_list);
833 		err = ubifs_wbuf_init(c, &c->jheads[i].wbuf);
834 		if (err)
835 			return err;
836 
837 		c->jheads[i].wbuf.sync_callback = &bud_wbuf_callback;
838 		c->jheads[i].wbuf.jhead = i;
839 		c->jheads[i].grouped = 1;
840 		c->jheads[i].log_hash = ubifs_hash_get_desc(c);
841 		if (IS_ERR(c->jheads[i].log_hash)) {
842 			err = PTR_ERR(c->jheads[i].log_hash);
843 			goto out;
844 		}
845 	}
846 
847 	/*
848 	 * Garbage Collector head does not need to be synchronized by timer.
849 	 * Also GC head nodes are not grouped.
850 	 */
851 	c->jheads[GCHD].wbuf.no_timer = 1;
852 	c->jheads[GCHD].grouped = 0;
853 
854 	return 0;
855 
856 out:
857 	while (i--)
858 		kfree(c->jheads[i].log_hash);
859 
860 	return err;
861 }
862 
863 /**
864  * free_wbufs - free write-buffers.
865  * @c: UBIFS file-system description object
866  */
867 static void free_wbufs(struct ubifs_info *c)
868 {
869 	int i;
870 
871 	if (c->jheads) {
872 		for (i = 0; i < c->jhead_cnt; i++) {
873 			kfree(c->jheads[i].wbuf.buf);
874 			kfree(c->jheads[i].wbuf.inodes);
875 			kfree(c->jheads[i].log_hash);
876 		}
877 		kfree(c->jheads);
878 		c->jheads = NULL;
879 	}
880 }
881 
882 /**
883  * free_orphans - free orphans.
884  * @c: UBIFS file-system description object
885  */
886 static void free_orphans(struct ubifs_info *c)
887 {
888 	struct ubifs_orphan *orph;
889 
890 	while (c->orph_dnext) {
891 		orph = c->orph_dnext;
892 		c->orph_dnext = orph->dnext;
893 		list_del(&orph->list);
894 		kfree(orph);
895 	}
896 
897 	while (!list_empty(&c->orph_list)) {
898 		orph = list_entry(c->orph_list.next, struct ubifs_orphan, list);
899 		list_del(&orph->list);
900 		kfree(orph);
901 		ubifs_err(c, "orphan list not empty at unmount");
902 	}
903 
904 	vfree(c->orph_buf);
905 	c->orph_buf = NULL;
906 }
907 
908 /**
909  * free_buds - free per-bud objects.
910  * @c: UBIFS file-system description object
911  */
912 static void free_buds(struct ubifs_info *c)
913 {
914 	struct ubifs_bud *bud, *n;
915 
916 	rbtree_postorder_for_each_entry_safe(bud, n, &c->buds, rb)
917 		kfree(bud);
918 }
919 
920 /**
921  * check_volume_empty - check if the UBI volume is empty.
922  * @c: UBIFS file-system description object
923  *
924  * This function checks if the UBIFS volume is empty by looking if its LEBs are
925  * mapped or not. The result of checking is stored in the @c->empty variable.
926  * Returns zero in case of success and a negative error code in case of
927  * failure.
928  */
929 static int check_volume_empty(struct ubifs_info *c)
930 {
931 	int lnum, err;
932 
933 	c->empty = 1;
934 	for (lnum = 0; lnum < c->leb_cnt; lnum++) {
935 		err = ubifs_is_mapped(c, lnum);
936 		if (unlikely(err < 0))
937 			return err;
938 		if (err == 1) {
939 			c->empty = 0;
940 			break;
941 		}
942 
943 		cond_resched();
944 	}
945 
946 	return 0;
947 }
948 
949 /*
950  * UBIFS mount options.
951  *
952  * Opt_fast_unmount: do not run a journal commit before un-mounting
953  * Opt_norm_unmount: run a journal commit before un-mounting
954  * Opt_bulk_read: enable bulk-reads
955  * Opt_no_bulk_read: disable bulk-reads
956  * Opt_chk_data_crc: check CRCs when reading data nodes
957  * Opt_no_chk_data_crc: do not check CRCs when reading data nodes
958  * Opt_override_compr: override default compressor
959  * Opt_assert: set ubifs_assert() action
960  * Opt_auth_key: The key name used for authentication
961  * Opt_auth_hash_name: The hash type used for authentication
962  * Opt_err: just end of array marker
963  */
964 enum {
965 	Opt_fast_unmount,
966 	Opt_norm_unmount,
967 	Opt_bulk_read,
968 	Opt_no_bulk_read,
969 	Opt_chk_data_crc,
970 	Opt_no_chk_data_crc,
971 	Opt_override_compr,
972 	Opt_assert,
973 	Opt_auth_key,
974 	Opt_auth_hash_name,
975 	Opt_ignore,
976 	Opt_err,
977 };
978 
979 static const match_table_t tokens = {
980 	{Opt_fast_unmount, "fast_unmount"},
981 	{Opt_norm_unmount, "norm_unmount"},
982 	{Opt_bulk_read, "bulk_read"},
983 	{Opt_no_bulk_read, "no_bulk_read"},
984 	{Opt_chk_data_crc, "chk_data_crc"},
985 	{Opt_no_chk_data_crc, "no_chk_data_crc"},
986 	{Opt_override_compr, "compr=%s"},
987 	{Opt_auth_key, "auth_key=%s"},
988 	{Opt_auth_hash_name, "auth_hash_name=%s"},
989 	{Opt_ignore, "ubi=%s"},
990 	{Opt_ignore, "vol=%s"},
991 	{Opt_assert, "assert=%s"},
992 	{Opt_err, NULL},
993 };
994 
995 /**
996  * parse_standard_option - parse a standard mount option.
997  * @option: the option to parse
998  *
999  * Normally, standard mount options like "sync" are passed to file-systems as
1000  * flags. However, when a "rootflags=" kernel boot parameter is used, they may
1001  * be present in the options string. This function tries to deal with this
1002  * situation and parse standard options. Returns 0 if the option was not
1003  * recognized, and the corresponding integer flag if it was.
1004  *
1005  * UBIFS is only interested in the "sync" option, so do not check for anything
1006  * else.
1007  */
1008 static int parse_standard_option(const char *option)
1009 {
1010 
1011 	pr_notice("UBIFS: parse %s\n", option);
1012 	if (!strcmp(option, "sync"))
1013 		return SB_SYNCHRONOUS;
1014 	return 0;
1015 }
1016 
1017 /**
1018  * ubifs_parse_options - parse mount parameters.
1019  * @c: UBIFS file-system description object
1020  * @options: parameters to parse
1021  * @is_remount: non-zero if this is FS re-mount
1022  *
1023  * This function parses UBIFS mount options and returns zero in case success
1024  * and a negative error code in case of failure.
1025  */
1026 static int ubifs_parse_options(struct ubifs_info *c, char *options,
1027 			       int is_remount)
1028 {
1029 	char *p;
1030 	substring_t args[MAX_OPT_ARGS];
1031 
1032 	if (!options)
1033 		return 0;
1034 
1035 	while ((p = strsep(&options, ","))) {
1036 		int token;
1037 
1038 		if (!*p)
1039 			continue;
1040 
1041 		token = match_token(p, tokens, args);
1042 		switch (token) {
1043 		/*
1044 		 * %Opt_fast_unmount and %Opt_norm_unmount options are ignored.
1045 		 * We accept them in order to be backward-compatible. But this
1046 		 * should be removed at some point.
1047 		 */
1048 		case Opt_fast_unmount:
1049 			c->mount_opts.unmount_mode = 2;
1050 			break;
1051 		case Opt_norm_unmount:
1052 			c->mount_opts.unmount_mode = 1;
1053 			break;
1054 		case Opt_bulk_read:
1055 			c->mount_opts.bulk_read = 2;
1056 			c->bulk_read = 1;
1057 			break;
1058 		case Opt_no_bulk_read:
1059 			c->mount_opts.bulk_read = 1;
1060 			c->bulk_read = 0;
1061 			break;
1062 		case Opt_chk_data_crc:
1063 			c->mount_opts.chk_data_crc = 2;
1064 			c->no_chk_data_crc = 0;
1065 			break;
1066 		case Opt_no_chk_data_crc:
1067 			c->mount_opts.chk_data_crc = 1;
1068 			c->no_chk_data_crc = 1;
1069 			break;
1070 		case Opt_override_compr:
1071 		{
1072 			char *name = match_strdup(&args[0]);
1073 
1074 			if (!name)
1075 				return -ENOMEM;
1076 			if (!strcmp(name, "none"))
1077 				c->mount_opts.compr_type = UBIFS_COMPR_NONE;
1078 			else if (!strcmp(name, "lzo"))
1079 				c->mount_opts.compr_type = UBIFS_COMPR_LZO;
1080 			else if (!strcmp(name, "zlib"))
1081 				c->mount_opts.compr_type = UBIFS_COMPR_ZLIB;
1082 			else if (!strcmp(name, "zstd"))
1083 				c->mount_opts.compr_type = UBIFS_COMPR_ZSTD;
1084 			else {
1085 				ubifs_err(c, "unknown compressor \"%s\"", name); //FIXME: is c ready?
1086 				kfree(name);
1087 				return -EINVAL;
1088 			}
1089 			kfree(name);
1090 			c->mount_opts.override_compr = 1;
1091 			c->default_compr = c->mount_opts.compr_type;
1092 			break;
1093 		}
1094 		case Opt_assert:
1095 		{
1096 			char *act = match_strdup(&args[0]);
1097 
1098 			if (!act)
1099 				return -ENOMEM;
1100 			if (!strcmp(act, "report"))
1101 				c->assert_action = ASSACT_REPORT;
1102 			else if (!strcmp(act, "read-only"))
1103 				c->assert_action = ASSACT_RO;
1104 			else if (!strcmp(act, "panic"))
1105 				c->assert_action = ASSACT_PANIC;
1106 			else {
1107 				ubifs_err(c, "unknown assert action \"%s\"", act);
1108 				kfree(act);
1109 				return -EINVAL;
1110 			}
1111 			kfree(act);
1112 			break;
1113 		}
1114 		case Opt_auth_key:
1115 			if (!is_remount) {
1116 				c->auth_key_name = kstrdup(args[0].from,
1117 								GFP_KERNEL);
1118 				if (!c->auth_key_name)
1119 					return -ENOMEM;
1120 			}
1121 			break;
1122 		case Opt_auth_hash_name:
1123 			if (!is_remount) {
1124 				c->auth_hash_name = kstrdup(args[0].from,
1125 								GFP_KERNEL);
1126 				if (!c->auth_hash_name)
1127 					return -ENOMEM;
1128 			}
1129 			break;
1130 		case Opt_ignore:
1131 			break;
1132 		default:
1133 		{
1134 			unsigned long flag;
1135 			struct super_block *sb = c->vfs_sb;
1136 
1137 			flag = parse_standard_option(p);
1138 			if (!flag) {
1139 				ubifs_err(c, "unrecognized mount option \"%s\" or missing value",
1140 					  p);
1141 				return -EINVAL;
1142 			}
1143 			sb->s_flags |= flag;
1144 			break;
1145 		}
1146 		}
1147 	}
1148 
1149 	return 0;
1150 }
1151 
1152 /*
1153  * ubifs_release_options - release mount parameters which have been dumped.
1154  * @c: UBIFS file-system description object
1155  */
1156 static void ubifs_release_options(struct ubifs_info *c)
1157 {
1158 	kfree(c->auth_key_name);
1159 	c->auth_key_name = NULL;
1160 	kfree(c->auth_hash_name);
1161 	c->auth_hash_name = NULL;
1162 }
1163 
1164 /**
1165  * destroy_journal - destroy journal data structures.
1166  * @c: UBIFS file-system description object
1167  *
1168  * This function destroys journal data structures including those that may have
1169  * been created by recovery functions.
1170  */
1171 static void destroy_journal(struct ubifs_info *c)
1172 {
1173 	while (!list_empty(&c->unclean_leb_list)) {
1174 		struct ubifs_unclean_leb *ucleb;
1175 
1176 		ucleb = list_entry(c->unclean_leb_list.next,
1177 				   struct ubifs_unclean_leb, list);
1178 		list_del(&ucleb->list);
1179 		kfree(ucleb);
1180 	}
1181 	while (!list_empty(&c->old_buds)) {
1182 		struct ubifs_bud *bud;
1183 
1184 		bud = list_entry(c->old_buds.next, struct ubifs_bud, list);
1185 		list_del(&bud->list);
1186 		kfree(bud);
1187 	}
1188 	ubifs_destroy_idx_gc(c);
1189 	ubifs_destroy_size_tree(c);
1190 	ubifs_tnc_close(c);
1191 	free_buds(c);
1192 }
1193 
1194 /**
1195  * bu_init - initialize bulk-read information.
1196  * @c: UBIFS file-system description object
1197  */
1198 static void bu_init(struct ubifs_info *c)
1199 {
1200 	ubifs_assert(c, c->bulk_read == 1);
1201 
1202 	if (c->bu.buf)
1203 		return; /* Already initialized */
1204 
1205 again:
1206 	c->bu.buf = kmalloc(c->max_bu_buf_len, GFP_KERNEL | __GFP_NOWARN);
1207 	if (!c->bu.buf) {
1208 		if (c->max_bu_buf_len > UBIFS_KMALLOC_OK) {
1209 			c->max_bu_buf_len = UBIFS_KMALLOC_OK;
1210 			goto again;
1211 		}
1212 
1213 		/* Just disable bulk-read */
1214 		ubifs_warn(c, "cannot allocate %d bytes of memory for bulk-read, disabling it",
1215 			   c->max_bu_buf_len);
1216 		c->mount_opts.bulk_read = 1;
1217 		c->bulk_read = 0;
1218 		return;
1219 	}
1220 }
1221 
1222 /**
1223  * check_free_space - check if there is enough free space to mount.
1224  * @c: UBIFS file-system description object
1225  *
1226  * This function makes sure UBIFS has enough free space to be mounted in
1227  * read/write mode. UBIFS must always have some free space to allow deletions.
1228  */
1229 static int check_free_space(struct ubifs_info *c)
1230 {
1231 	ubifs_assert(c, c->dark_wm > 0);
1232 	if (c->lst.total_free + c->lst.total_dirty < c->dark_wm) {
1233 		ubifs_err(c, "insufficient free space to mount in R/W mode");
1234 		ubifs_dump_budg(c, &c->bi);
1235 		ubifs_dump_lprops(c);
1236 		return -ENOSPC;
1237 	}
1238 	return 0;
1239 }
1240 
1241 /**
1242  * mount_ubifs - mount UBIFS file-system.
1243  * @c: UBIFS file-system description object
1244  *
1245  * This function mounts UBIFS file system. Returns zero in case of success and
1246  * a negative error code in case of failure.
1247  */
1248 static int mount_ubifs(struct ubifs_info *c)
1249 {
1250 	int err;
1251 	long long x, y;
1252 	size_t sz;
1253 
1254 	c->ro_mount = !!sb_rdonly(c->vfs_sb);
1255 	/* Suppress error messages while probing if SB_SILENT is set */
1256 	c->probing = !!(c->vfs_sb->s_flags & SB_SILENT);
1257 
1258 	err = init_constants_early(c);
1259 	if (err)
1260 		return err;
1261 
1262 	err = ubifs_debugging_init(c);
1263 	if (err)
1264 		return err;
1265 
1266 	err = check_volume_empty(c);
1267 	if (err)
1268 		goto out_free;
1269 
1270 	if (c->empty && (c->ro_mount || c->ro_media)) {
1271 		/*
1272 		 * This UBI volume is empty, and read-only, or the file system
1273 		 * is mounted read-only - we cannot format it.
1274 		 */
1275 		ubifs_err(c, "can't format empty UBI volume: read-only %s",
1276 			  c->ro_media ? "UBI volume" : "mount");
1277 		err = -EROFS;
1278 		goto out_free;
1279 	}
1280 
1281 	if (c->ro_media && !c->ro_mount) {
1282 		ubifs_err(c, "cannot mount read-write - read-only media");
1283 		err = -EROFS;
1284 		goto out_free;
1285 	}
1286 
1287 	/*
1288 	 * The requirement for the buffer is that it should fit indexing B-tree
1289 	 * height amount of integers. We assume the height if the TNC tree will
1290 	 * never exceed 64.
1291 	 */
1292 	err = -ENOMEM;
1293 	c->bottom_up_buf = kmalloc_array(BOTTOM_UP_HEIGHT, sizeof(int),
1294 					 GFP_KERNEL);
1295 	if (!c->bottom_up_buf)
1296 		goto out_free;
1297 
1298 	c->sbuf = vmalloc(c->leb_size);
1299 	if (!c->sbuf)
1300 		goto out_free;
1301 
1302 	if (!c->ro_mount) {
1303 		c->ileb_buf = vmalloc(c->leb_size);
1304 		if (!c->ileb_buf)
1305 			goto out_free;
1306 	}
1307 
1308 	if (c->bulk_read == 1)
1309 		bu_init(c);
1310 
1311 	if (!c->ro_mount) {
1312 		c->write_reserve_buf = kmalloc(COMPRESSED_DATA_NODE_BUF_SZ + \
1313 					       UBIFS_CIPHER_BLOCK_SIZE,
1314 					       GFP_KERNEL);
1315 		if (!c->write_reserve_buf)
1316 			goto out_free;
1317 	}
1318 
1319 	c->mounting = 1;
1320 
1321 	if (c->auth_key_name) {
1322 		if (IS_ENABLED(CONFIG_UBIFS_FS_AUTHENTICATION)) {
1323 			err = ubifs_init_authentication(c);
1324 			if (err)
1325 				goto out_free;
1326 		} else {
1327 			ubifs_err(c, "auth_key_name, but UBIFS is built without"
1328 				  " authentication support");
1329 			err = -EINVAL;
1330 			goto out_free;
1331 		}
1332 	}
1333 
1334 	err = ubifs_read_superblock(c);
1335 	if (err)
1336 		goto out_auth;
1337 
1338 	c->probing = 0;
1339 
1340 	/*
1341 	 * Make sure the compressor which is set as default in the superblock
1342 	 * or overridden by mount options is actually compiled in.
1343 	 */
1344 	if (!ubifs_compr_present(c, c->default_compr)) {
1345 		ubifs_err(c, "'compressor \"%s\" is not compiled in",
1346 			  ubifs_compr_name(c, c->default_compr));
1347 		err = -ENOTSUPP;
1348 		goto out_auth;
1349 	}
1350 
1351 	err = init_constants_sb(c);
1352 	if (err)
1353 		goto out_auth;
1354 
1355 	sz = ALIGN(c->max_idx_node_sz, c->min_io_size) * 2;
1356 	c->cbuf = kmalloc(sz, GFP_NOFS);
1357 	if (!c->cbuf) {
1358 		err = -ENOMEM;
1359 		goto out_auth;
1360 	}
1361 
1362 	err = alloc_wbufs(c);
1363 	if (err)
1364 		goto out_cbuf;
1365 
1366 	sprintf(c->bgt_name, BGT_NAME_PATTERN, c->vi.ubi_num, c->vi.vol_id);
1367 	if (!c->ro_mount) {
1368 		/* Create background thread */
1369 		c->bgt = kthread_create(ubifs_bg_thread, c, "%s", c->bgt_name);
1370 		if (IS_ERR(c->bgt)) {
1371 			err = PTR_ERR(c->bgt);
1372 			c->bgt = NULL;
1373 			ubifs_err(c, "cannot spawn \"%s\", error %d",
1374 				  c->bgt_name, err);
1375 			goto out_wbufs;
1376 		}
1377 		wake_up_process(c->bgt);
1378 	}
1379 
1380 	err = ubifs_read_master(c);
1381 	if (err)
1382 		goto out_master;
1383 
1384 	init_constants_master(c);
1385 
1386 	if ((c->mst_node->flags & cpu_to_le32(UBIFS_MST_DIRTY)) != 0) {
1387 		ubifs_msg(c, "recovery needed");
1388 		c->need_recovery = 1;
1389 	}
1390 
1391 	if (c->need_recovery && !c->ro_mount) {
1392 		err = ubifs_recover_inl_heads(c, c->sbuf);
1393 		if (err)
1394 			goto out_master;
1395 	}
1396 
1397 	err = ubifs_lpt_init(c, 1, !c->ro_mount);
1398 	if (err)
1399 		goto out_master;
1400 
1401 	if (!c->ro_mount && c->space_fixup) {
1402 		err = ubifs_fixup_free_space(c);
1403 		if (err)
1404 			goto out_lpt;
1405 	}
1406 
1407 	if (!c->ro_mount && !c->need_recovery) {
1408 		/*
1409 		 * Set the "dirty" flag so that if we reboot uncleanly we
1410 		 * will notice this immediately on the next mount.
1411 		 */
1412 		c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
1413 		err = ubifs_write_master(c);
1414 		if (err)
1415 			goto out_lpt;
1416 	}
1417 
1418 	/*
1419 	 * Handle offline signed images: Now that the master node is
1420 	 * written and its validation no longer depends on the hash
1421 	 * in the superblock, we can update the offline signed
1422 	 * superblock with a HMAC version,
1423 	 */
1424 	if (ubifs_authenticated(c) && ubifs_hmac_zero(c, c->sup_node->hmac)) {
1425 		err = ubifs_hmac_wkm(c, c->sup_node->hmac_wkm);
1426 		if (err)
1427 			goto out_lpt;
1428 		c->superblock_need_write = 1;
1429 	}
1430 
1431 	if (!c->ro_mount && c->superblock_need_write) {
1432 		err = ubifs_write_sb_node(c, c->sup_node);
1433 		if (err)
1434 			goto out_lpt;
1435 		c->superblock_need_write = 0;
1436 	}
1437 
1438 	err = dbg_check_idx_size(c, c->bi.old_idx_sz);
1439 	if (err)
1440 		goto out_lpt;
1441 
1442 	err = ubifs_replay_journal(c);
1443 	if (err)
1444 		goto out_journal;
1445 
1446 	/* Calculate 'min_idx_lebs' after journal replay */
1447 	c->bi.min_idx_lebs = ubifs_calc_min_idx_lebs(c);
1448 
1449 	err = ubifs_mount_orphans(c, c->need_recovery, c->ro_mount);
1450 	if (err)
1451 		goto out_orphans;
1452 
1453 	if (!c->ro_mount) {
1454 		int lnum;
1455 
1456 		err = check_free_space(c);
1457 		if (err)
1458 			goto out_orphans;
1459 
1460 		/* Check for enough log space */
1461 		lnum = c->lhead_lnum + 1;
1462 		if (lnum >= UBIFS_LOG_LNUM + c->log_lebs)
1463 			lnum = UBIFS_LOG_LNUM;
1464 		if (lnum == c->ltail_lnum) {
1465 			err = ubifs_consolidate_log(c);
1466 			if (err)
1467 				goto out_orphans;
1468 		}
1469 
1470 		if (c->need_recovery) {
1471 			if (!ubifs_authenticated(c)) {
1472 				err = ubifs_recover_size(c, true);
1473 				if (err)
1474 					goto out_orphans;
1475 			}
1476 
1477 			err = ubifs_rcvry_gc_commit(c);
1478 			if (err)
1479 				goto out_orphans;
1480 
1481 			if (ubifs_authenticated(c)) {
1482 				err = ubifs_recover_size(c, false);
1483 				if (err)
1484 					goto out_orphans;
1485 			}
1486 		} else {
1487 			err = take_gc_lnum(c);
1488 			if (err)
1489 				goto out_orphans;
1490 
1491 			/*
1492 			 * GC LEB may contain garbage if there was an unclean
1493 			 * reboot, and it should be un-mapped.
1494 			 */
1495 			err = ubifs_leb_unmap(c, c->gc_lnum);
1496 			if (err)
1497 				goto out_orphans;
1498 		}
1499 
1500 		err = dbg_check_lprops(c);
1501 		if (err)
1502 			goto out_orphans;
1503 	} else if (c->need_recovery) {
1504 		err = ubifs_recover_size(c, false);
1505 		if (err)
1506 			goto out_orphans;
1507 	} else {
1508 		/*
1509 		 * Even if we mount read-only, we have to set space in GC LEB
1510 		 * to proper value because this affects UBIFS free space
1511 		 * reporting. We do not want to have a situation when
1512 		 * re-mounting from R/O to R/W changes amount of free space.
1513 		 */
1514 		err = take_gc_lnum(c);
1515 		if (err)
1516 			goto out_orphans;
1517 	}
1518 
1519 	spin_lock(&ubifs_infos_lock);
1520 	list_add_tail(&c->infos_list, &ubifs_infos);
1521 	spin_unlock(&ubifs_infos_lock);
1522 
1523 	if (c->need_recovery) {
1524 		if (c->ro_mount)
1525 			ubifs_msg(c, "recovery deferred");
1526 		else {
1527 			c->need_recovery = 0;
1528 			ubifs_msg(c, "recovery completed");
1529 			/*
1530 			 * GC LEB has to be empty and taken at this point. But
1531 			 * the journal head LEBs may also be accounted as
1532 			 * "empty taken" if they are empty.
1533 			 */
1534 			ubifs_assert(c, c->lst.taken_empty_lebs > 0);
1535 		}
1536 	} else
1537 		ubifs_assert(c, c->lst.taken_empty_lebs > 0);
1538 
1539 	err = dbg_check_filesystem(c);
1540 	if (err)
1541 		goto out_infos;
1542 
1543 	dbg_debugfs_init_fs(c);
1544 
1545 	c->mounting = 0;
1546 
1547 	ubifs_msg(c, "UBIFS: mounted UBI device %d, volume %d, name \"%s\"%s",
1548 		  c->vi.ubi_num, c->vi.vol_id, c->vi.name,
1549 		  c->ro_mount ? ", R/O mode" : "");
1550 	x = (long long)c->main_lebs * c->leb_size;
1551 	y = (long long)c->log_lebs * c->leb_size + c->max_bud_bytes;
1552 	ubifs_msg(c, "LEB size: %d bytes (%d KiB), min./max. I/O unit sizes: %d bytes/%d bytes",
1553 		  c->leb_size, c->leb_size >> 10, c->min_io_size,
1554 		  c->max_write_size);
1555 	ubifs_msg(c, "FS size: %lld bytes (%lld MiB, %d LEBs), max %d LEBs, journal size %lld bytes (%lld MiB, %d LEBs)",
1556 		  x, x >> 20, c->main_lebs, c->max_leb_cnt,
1557 		  y, y >> 20, c->log_lebs + c->max_bud_cnt);
1558 	ubifs_msg(c, "reserved for root: %llu bytes (%llu KiB)",
1559 		  c->report_rp_size, c->report_rp_size >> 10);
1560 	ubifs_msg(c, "media format: w%d/r%d (latest is w%d/r%d), UUID %pUB%s",
1561 		  c->fmt_version, c->ro_compat_version,
1562 		  UBIFS_FORMAT_VERSION, UBIFS_RO_COMPAT_VERSION, c->uuid,
1563 		  c->big_lpt ? ", big LPT model" : ", small LPT model");
1564 
1565 	dbg_gen("default compressor:  %s", ubifs_compr_name(c, c->default_compr));
1566 	dbg_gen("data journal heads:  %d",
1567 		c->jhead_cnt - NONDATA_JHEADS_CNT);
1568 	dbg_gen("log LEBs:            %d (%d - %d)",
1569 		c->log_lebs, UBIFS_LOG_LNUM, c->log_last);
1570 	dbg_gen("LPT area LEBs:       %d (%d - %d)",
1571 		c->lpt_lebs, c->lpt_first, c->lpt_last);
1572 	dbg_gen("orphan area LEBs:    %d (%d - %d)",
1573 		c->orph_lebs, c->orph_first, c->orph_last);
1574 	dbg_gen("main area LEBs:      %d (%d - %d)",
1575 		c->main_lebs, c->main_first, c->leb_cnt - 1);
1576 	dbg_gen("index LEBs:          %d", c->lst.idx_lebs);
1577 	dbg_gen("total index bytes:   %llu (%llu KiB, %llu MiB)",
1578 		c->bi.old_idx_sz, c->bi.old_idx_sz >> 10,
1579 		c->bi.old_idx_sz >> 20);
1580 	dbg_gen("key hash type:       %d", c->key_hash_type);
1581 	dbg_gen("tree fanout:         %d", c->fanout);
1582 	dbg_gen("reserved GC LEB:     %d", c->gc_lnum);
1583 	dbg_gen("max. znode size      %d", c->max_znode_sz);
1584 	dbg_gen("max. index node size %d", c->max_idx_node_sz);
1585 	dbg_gen("node sizes:          data %zu, inode %zu, dentry %zu",
1586 		UBIFS_DATA_NODE_SZ, UBIFS_INO_NODE_SZ, UBIFS_DENT_NODE_SZ);
1587 	dbg_gen("node sizes:          trun %zu, sb %zu, master %zu",
1588 		UBIFS_TRUN_NODE_SZ, UBIFS_SB_NODE_SZ, UBIFS_MST_NODE_SZ);
1589 	dbg_gen("node sizes:          ref %zu, cmt. start %zu, orph %zu",
1590 		UBIFS_REF_NODE_SZ, UBIFS_CS_NODE_SZ, UBIFS_ORPH_NODE_SZ);
1591 	dbg_gen("max. node sizes:     data %zu, inode %zu dentry %zu, idx %d",
1592 		UBIFS_MAX_DATA_NODE_SZ, UBIFS_MAX_INO_NODE_SZ,
1593 		UBIFS_MAX_DENT_NODE_SZ, ubifs_idx_node_sz(c, c->fanout));
1594 	dbg_gen("dead watermark:      %d", c->dead_wm);
1595 	dbg_gen("dark watermark:      %d", c->dark_wm);
1596 	dbg_gen("LEB overhead:        %d", c->leb_overhead);
1597 	x = (long long)c->main_lebs * c->dark_wm;
1598 	dbg_gen("max. dark space:     %lld (%lld KiB, %lld MiB)",
1599 		x, x >> 10, x >> 20);
1600 	dbg_gen("maximum bud bytes:   %lld (%lld KiB, %lld MiB)",
1601 		c->max_bud_bytes, c->max_bud_bytes >> 10,
1602 		c->max_bud_bytes >> 20);
1603 	dbg_gen("BG commit bud bytes: %lld (%lld KiB, %lld MiB)",
1604 		c->bg_bud_bytes, c->bg_bud_bytes >> 10,
1605 		c->bg_bud_bytes >> 20);
1606 	dbg_gen("current bud bytes    %lld (%lld KiB, %lld MiB)",
1607 		c->bud_bytes, c->bud_bytes >> 10, c->bud_bytes >> 20);
1608 	dbg_gen("max. seq. number:    %llu", c->max_sqnum);
1609 	dbg_gen("commit number:       %llu", c->cmt_no);
1610 	dbg_gen("max. xattrs per inode: %d", ubifs_xattr_max_cnt(c));
1611 	dbg_gen("max orphans:           %d", c->max_orphans);
1612 
1613 	return 0;
1614 
1615 out_infos:
1616 	spin_lock(&ubifs_infos_lock);
1617 	list_del(&c->infos_list);
1618 	spin_unlock(&ubifs_infos_lock);
1619 out_orphans:
1620 	free_orphans(c);
1621 out_journal:
1622 	destroy_journal(c);
1623 out_lpt:
1624 	ubifs_lpt_free(c, 0);
1625 out_master:
1626 	kfree(c->mst_node);
1627 	kfree(c->rcvrd_mst_node);
1628 	if (c->bgt)
1629 		kthread_stop(c->bgt);
1630 out_wbufs:
1631 	free_wbufs(c);
1632 out_cbuf:
1633 	kfree(c->cbuf);
1634 out_auth:
1635 	ubifs_exit_authentication(c);
1636 out_free:
1637 	kfree(c->write_reserve_buf);
1638 	kfree(c->bu.buf);
1639 	vfree(c->ileb_buf);
1640 	vfree(c->sbuf);
1641 	kfree(c->bottom_up_buf);
1642 	kfree(c->sup_node);
1643 	ubifs_debugging_exit(c);
1644 	return err;
1645 }
1646 
1647 /**
1648  * ubifs_umount - un-mount UBIFS file-system.
1649  * @c: UBIFS file-system description object
1650  *
1651  * Note, this function is called to free allocated resourced when un-mounting,
1652  * as well as free resources when an error occurred while we were half way
1653  * through mounting (error path cleanup function). So it has to make sure the
1654  * resource was actually allocated before freeing it.
1655  */
1656 static void ubifs_umount(struct ubifs_info *c)
1657 {
1658 	dbg_gen("un-mounting UBI device %d, volume %d", c->vi.ubi_num,
1659 		c->vi.vol_id);
1660 
1661 	dbg_debugfs_exit_fs(c);
1662 	spin_lock(&ubifs_infos_lock);
1663 	list_del(&c->infos_list);
1664 	spin_unlock(&ubifs_infos_lock);
1665 
1666 	if (c->bgt)
1667 		kthread_stop(c->bgt);
1668 
1669 	destroy_journal(c);
1670 	free_wbufs(c);
1671 	free_orphans(c);
1672 	ubifs_lpt_free(c, 0);
1673 	ubifs_exit_authentication(c);
1674 
1675 	ubifs_release_options(c);
1676 	kfree(c->cbuf);
1677 	kfree(c->rcvrd_mst_node);
1678 	kfree(c->mst_node);
1679 	kfree(c->write_reserve_buf);
1680 	kfree(c->bu.buf);
1681 	vfree(c->ileb_buf);
1682 	vfree(c->sbuf);
1683 	kfree(c->bottom_up_buf);
1684 	kfree(c->sup_node);
1685 	ubifs_debugging_exit(c);
1686 }
1687 
1688 /**
1689  * ubifs_remount_rw - re-mount in read-write mode.
1690  * @c: UBIFS file-system description object
1691  *
1692  * UBIFS avoids allocating many unnecessary resources when mounted in read-only
1693  * mode. This function allocates the needed resources and re-mounts UBIFS in
1694  * read-write mode.
1695  */
1696 static int ubifs_remount_rw(struct ubifs_info *c)
1697 {
1698 	int err, lnum;
1699 
1700 	if (c->rw_incompat) {
1701 		ubifs_err(c, "the file-system is not R/W-compatible");
1702 		ubifs_msg(c, "on-flash format version is w%d/r%d, but software only supports up to version w%d/r%d",
1703 			  c->fmt_version, c->ro_compat_version,
1704 			  UBIFS_FORMAT_VERSION, UBIFS_RO_COMPAT_VERSION);
1705 		return -EROFS;
1706 	}
1707 
1708 	mutex_lock(&c->umount_mutex);
1709 	dbg_save_space_info(c);
1710 	c->remounting_rw = 1;
1711 	c->ro_mount = 0;
1712 
1713 	if (c->space_fixup) {
1714 		err = ubifs_fixup_free_space(c);
1715 		if (err)
1716 			goto out;
1717 	}
1718 
1719 	err = check_free_space(c);
1720 	if (err)
1721 		goto out;
1722 
1723 	if (c->need_recovery) {
1724 		ubifs_msg(c, "completing deferred recovery");
1725 		err = ubifs_write_rcvrd_mst_node(c);
1726 		if (err)
1727 			goto out;
1728 		if (!ubifs_authenticated(c)) {
1729 			err = ubifs_recover_size(c, true);
1730 			if (err)
1731 				goto out;
1732 		}
1733 		err = ubifs_clean_lebs(c, c->sbuf);
1734 		if (err)
1735 			goto out;
1736 		err = ubifs_recover_inl_heads(c, c->sbuf);
1737 		if (err)
1738 			goto out;
1739 	} else {
1740 		/* A readonly mount is not allowed to have orphans */
1741 		ubifs_assert(c, c->tot_orphans == 0);
1742 		err = ubifs_clear_orphans(c);
1743 		if (err)
1744 			goto out;
1745 	}
1746 
1747 	if (!(c->mst_node->flags & cpu_to_le32(UBIFS_MST_DIRTY))) {
1748 		c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
1749 		err = ubifs_write_master(c);
1750 		if (err)
1751 			goto out;
1752 	}
1753 
1754 	if (c->superblock_need_write) {
1755 		struct ubifs_sb_node *sup = c->sup_node;
1756 
1757 		err = ubifs_write_sb_node(c, sup);
1758 		if (err)
1759 			goto out;
1760 
1761 		c->superblock_need_write = 0;
1762 	}
1763 
1764 	c->ileb_buf = vmalloc(c->leb_size);
1765 	if (!c->ileb_buf) {
1766 		err = -ENOMEM;
1767 		goto out;
1768 	}
1769 
1770 	c->write_reserve_buf = kmalloc(COMPRESSED_DATA_NODE_BUF_SZ + \
1771 				       UBIFS_CIPHER_BLOCK_SIZE, GFP_KERNEL);
1772 	if (!c->write_reserve_buf) {
1773 		err = -ENOMEM;
1774 		goto out;
1775 	}
1776 
1777 	err = ubifs_lpt_init(c, 0, 1);
1778 	if (err)
1779 		goto out;
1780 
1781 	/* Create background thread */
1782 	c->bgt = kthread_create(ubifs_bg_thread, c, "%s", c->bgt_name);
1783 	if (IS_ERR(c->bgt)) {
1784 		err = PTR_ERR(c->bgt);
1785 		c->bgt = NULL;
1786 		ubifs_err(c, "cannot spawn \"%s\", error %d",
1787 			  c->bgt_name, err);
1788 		goto out;
1789 	}
1790 	wake_up_process(c->bgt);
1791 
1792 	c->orph_buf = vmalloc(c->leb_size);
1793 	if (!c->orph_buf) {
1794 		err = -ENOMEM;
1795 		goto out;
1796 	}
1797 
1798 	/* Check for enough log space */
1799 	lnum = c->lhead_lnum + 1;
1800 	if (lnum >= UBIFS_LOG_LNUM + c->log_lebs)
1801 		lnum = UBIFS_LOG_LNUM;
1802 	if (lnum == c->ltail_lnum) {
1803 		err = ubifs_consolidate_log(c);
1804 		if (err)
1805 			goto out;
1806 	}
1807 
1808 	if (c->need_recovery) {
1809 		err = ubifs_rcvry_gc_commit(c);
1810 		if (err)
1811 			goto out;
1812 
1813 		if (ubifs_authenticated(c)) {
1814 			err = ubifs_recover_size(c, false);
1815 			if (err)
1816 				goto out;
1817 		}
1818 	} else {
1819 		err = ubifs_leb_unmap(c, c->gc_lnum);
1820 	}
1821 	if (err)
1822 		goto out;
1823 
1824 	dbg_gen("re-mounted read-write");
1825 	c->remounting_rw = 0;
1826 
1827 	if (c->need_recovery) {
1828 		c->need_recovery = 0;
1829 		ubifs_msg(c, "deferred recovery completed");
1830 	} else {
1831 		/*
1832 		 * Do not run the debugging space check if the were doing
1833 		 * recovery, because when we saved the information we had the
1834 		 * file-system in a state where the TNC and lprops has been
1835 		 * modified in memory, but all the I/O operations (including a
1836 		 * commit) were deferred. So the file-system was in
1837 		 * "non-committed" state. Now the file-system is in committed
1838 		 * state, and of course the amount of free space will change
1839 		 * because, for example, the old index size was imprecise.
1840 		 */
1841 		err = dbg_check_space_info(c);
1842 	}
1843 
1844 	mutex_unlock(&c->umount_mutex);
1845 	return err;
1846 
1847 out:
1848 	c->ro_mount = 1;
1849 	vfree(c->orph_buf);
1850 	c->orph_buf = NULL;
1851 	if (c->bgt) {
1852 		kthread_stop(c->bgt);
1853 		c->bgt = NULL;
1854 	}
1855 	free_wbufs(c);
1856 	kfree(c->write_reserve_buf);
1857 	c->write_reserve_buf = NULL;
1858 	vfree(c->ileb_buf);
1859 	c->ileb_buf = NULL;
1860 	ubifs_lpt_free(c, 1);
1861 	c->remounting_rw = 0;
1862 	mutex_unlock(&c->umount_mutex);
1863 	return err;
1864 }
1865 
1866 /**
1867  * ubifs_remount_ro - re-mount in read-only mode.
1868  * @c: UBIFS file-system description object
1869  *
1870  * We assume VFS has stopped writing. Possibly the background thread could be
1871  * running a commit, however kthread_stop will wait in that case.
1872  */
1873 static void ubifs_remount_ro(struct ubifs_info *c)
1874 {
1875 	int i, err;
1876 
1877 	ubifs_assert(c, !c->need_recovery);
1878 	ubifs_assert(c, !c->ro_mount);
1879 
1880 	mutex_lock(&c->umount_mutex);
1881 	if (c->bgt) {
1882 		kthread_stop(c->bgt);
1883 		c->bgt = NULL;
1884 	}
1885 
1886 	dbg_save_space_info(c);
1887 
1888 	for (i = 0; i < c->jhead_cnt; i++) {
1889 		err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
1890 		if (err)
1891 			ubifs_ro_mode(c, err);
1892 	}
1893 
1894 	c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_DIRTY);
1895 	c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
1896 	c->mst_node->gc_lnum = cpu_to_le32(c->gc_lnum);
1897 	err = ubifs_write_master(c);
1898 	if (err)
1899 		ubifs_ro_mode(c, err);
1900 
1901 	vfree(c->orph_buf);
1902 	c->orph_buf = NULL;
1903 	kfree(c->write_reserve_buf);
1904 	c->write_reserve_buf = NULL;
1905 	vfree(c->ileb_buf);
1906 	c->ileb_buf = NULL;
1907 	ubifs_lpt_free(c, 1);
1908 	c->ro_mount = 1;
1909 	err = dbg_check_space_info(c);
1910 	if (err)
1911 		ubifs_ro_mode(c, err);
1912 	mutex_unlock(&c->umount_mutex);
1913 }
1914 
1915 static void ubifs_put_super(struct super_block *sb)
1916 {
1917 	int i;
1918 	struct ubifs_info *c = sb->s_fs_info;
1919 
1920 	ubifs_msg(c, "un-mount UBI device %d", c->vi.ubi_num);
1921 
1922 	/*
1923 	 * The following asserts are only valid if there has not been a failure
1924 	 * of the media. For example, there will be dirty inodes if we failed
1925 	 * to write them back because of I/O errors.
1926 	 */
1927 	if (!c->ro_error) {
1928 		ubifs_assert(c, c->bi.idx_growth == 0);
1929 		ubifs_assert(c, c->bi.dd_growth == 0);
1930 		ubifs_assert(c, c->bi.data_growth == 0);
1931 	}
1932 
1933 	/*
1934 	 * The 'c->umount_lock' prevents races between UBIFS memory shrinker
1935 	 * and file system un-mount. Namely, it prevents the shrinker from
1936 	 * picking this superblock for shrinking - it will be just skipped if
1937 	 * the mutex is locked.
1938 	 */
1939 	mutex_lock(&c->umount_mutex);
1940 	if (!c->ro_mount) {
1941 		/*
1942 		 * First of all kill the background thread to make sure it does
1943 		 * not interfere with un-mounting and freeing resources.
1944 		 */
1945 		if (c->bgt) {
1946 			kthread_stop(c->bgt);
1947 			c->bgt = NULL;
1948 		}
1949 
1950 		/*
1951 		 * On fatal errors c->ro_error is set to 1, in which case we do
1952 		 * not write the master node.
1953 		 */
1954 		if (!c->ro_error) {
1955 			int err;
1956 
1957 			/* Synchronize write-buffers */
1958 			for (i = 0; i < c->jhead_cnt; i++) {
1959 				err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
1960 				if (err)
1961 					ubifs_ro_mode(c, err);
1962 			}
1963 
1964 			/*
1965 			 * We are being cleanly unmounted which means the
1966 			 * orphans were killed - indicate this in the master
1967 			 * node. Also save the reserved GC LEB number.
1968 			 */
1969 			c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_DIRTY);
1970 			c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
1971 			c->mst_node->gc_lnum = cpu_to_le32(c->gc_lnum);
1972 			err = ubifs_write_master(c);
1973 			if (err)
1974 				/*
1975 				 * Recovery will attempt to fix the master area
1976 				 * next mount, so we just print a message and
1977 				 * continue to unmount normally.
1978 				 */
1979 				ubifs_err(c, "failed to write master node, error %d",
1980 					  err);
1981 		} else {
1982 			for (i = 0; i < c->jhead_cnt; i++)
1983 				/* Make sure write-buffer timers are canceled */
1984 				hrtimer_cancel(&c->jheads[i].wbuf.timer);
1985 		}
1986 	}
1987 
1988 	ubifs_umount(c);
1989 	ubi_close_volume(c->ubi);
1990 	mutex_unlock(&c->umount_mutex);
1991 }
1992 
1993 static int ubifs_remount_fs(struct super_block *sb, int *flags, char *data)
1994 {
1995 	int err;
1996 	struct ubifs_info *c = sb->s_fs_info;
1997 
1998 	sync_filesystem(sb);
1999 	dbg_gen("old flags %#lx, new flags %#x", sb->s_flags, *flags);
2000 
2001 	err = ubifs_parse_options(c, data, 1);
2002 	if (err) {
2003 		ubifs_err(c, "invalid or unknown remount parameter");
2004 		return err;
2005 	}
2006 
2007 	if (c->ro_mount && !(*flags & SB_RDONLY)) {
2008 		if (c->ro_error) {
2009 			ubifs_msg(c, "cannot re-mount R/W due to prior errors");
2010 			return -EROFS;
2011 		}
2012 		if (c->ro_media) {
2013 			ubifs_msg(c, "cannot re-mount R/W - UBI volume is R/O");
2014 			return -EROFS;
2015 		}
2016 		err = ubifs_remount_rw(c);
2017 		if (err)
2018 			return err;
2019 	} else if (!c->ro_mount && (*flags & SB_RDONLY)) {
2020 		if (c->ro_error) {
2021 			ubifs_msg(c, "cannot re-mount R/O due to prior errors");
2022 			return -EROFS;
2023 		}
2024 		ubifs_remount_ro(c);
2025 	}
2026 
2027 	if (c->bulk_read == 1)
2028 		bu_init(c);
2029 	else {
2030 		dbg_gen("disable bulk-read");
2031 		mutex_lock(&c->bu_mutex);
2032 		kfree(c->bu.buf);
2033 		c->bu.buf = NULL;
2034 		mutex_unlock(&c->bu_mutex);
2035 	}
2036 
2037 	if (!c->need_recovery)
2038 		ubifs_assert(c, c->lst.taken_empty_lebs > 0);
2039 
2040 	return 0;
2041 }
2042 
2043 const struct super_operations ubifs_super_operations = {
2044 	.alloc_inode   = ubifs_alloc_inode,
2045 	.free_inode    = ubifs_free_inode,
2046 	.put_super     = ubifs_put_super,
2047 	.write_inode   = ubifs_write_inode,
2048 	.drop_inode    = ubifs_drop_inode,
2049 	.evict_inode   = ubifs_evict_inode,
2050 	.statfs        = ubifs_statfs,
2051 	.dirty_inode   = ubifs_dirty_inode,
2052 	.remount_fs    = ubifs_remount_fs,
2053 	.show_options  = ubifs_show_options,
2054 	.sync_fs       = ubifs_sync_fs,
2055 };
2056 
2057 /**
2058  * open_ubi - parse UBI device name string and open the UBI device.
2059  * @name: UBI volume name
2060  * @mode: UBI volume open mode
2061  *
2062  * The primary method of mounting UBIFS is by specifying the UBI volume
2063  * character device node path. However, UBIFS may also be mounted withoug any
2064  * character device node using one of the following methods:
2065  *
2066  * o ubiX_Y    - mount UBI device number X, volume Y;
2067  * o ubiY      - mount UBI device number 0, volume Y;
2068  * o ubiX:NAME - mount UBI device X, volume with name NAME;
2069  * o ubi:NAME  - mount UBI device 0, volume with name NAME.
2070  *
2071  * Alternative '!' separator may be used instead of ':' (because some shells
2072  * like busybox may interpret ':' as an NFS host name separator). This function
2073  * returns UBI volume description object in case of success and a negative
2074  * error code in case of failure.
2075  */
2076 static struct ubi_volume_desc *open_ubi(const char *name, int mode)
2077 {
2078 	struct ubi_volume_desc *ubi;
2079 	int dev, vol;
2080 	char *endptr;
2081 
2082 	if (!name || !*name)
2083 		return ERR_PTR(-EINVAL);
2084 
2085 	/* First, try to open using the device node path method */
2086 	ubi = ubi_open_volume_path(name, mode);
2087 	if (!IS_ERR(ubi))
2088 		return ubi;
2089 
2090 	/* Try the "nodev" method */
2091 	if (name[0] != 'u' || name[1] != 'b' || name[2] != 'i')
2092 		return ERR_PTR(-EINVAL);
2093 
2094 	/* ubi:NAME method */
2095 	if ((name[3] == ':' || name[3] == '!') && name[4] != '\0')
2096 		return ubi_open_volume_nm(0, name + 4, mode);
2097 
2098 	if (!isdigit(name[3]))
2099 		return ERR_PTR(-EINVAL);
2100 
2101 	dev = simple_strtoul(name + 3, &endptr, 0);
2102 
2103 	/* ubiY method */
2104 	if (*endptr == '\0')
2105 		return ubi_open_volume(0, dev, mode);
2106 
2107 	/* ubiX_Y method */
2108 	if (*endptr == '_' && isdigit(endptr[1])) {
2109 		vol = simple_strtoul(endptr + 1, &endptr, 0);
2110 		if (*endptr != '\0')
2111 			return ERR_PTR(-EINVAL);
2112 		return ubi_open_volume(dev, vol, mode);
2113 	}
2114 
2115 	/* ubiX:NAME method */
2116 	if ((*endptr == ':' || *endptr == '!') && endptr[1] != '\0')
2117 		return ubi_open_volume_nm(dev, ++endptr, mode);
2118 
2119 	return ERR_PTR(-EINVAL);
2120 }
2121 
2122 static struct ubifs_info *alloc_ubifs_info(struct ubi_volume_desc *ubi)
2123 {
2124 	struct ubifs_info *c;
2125 
2126 	c = kzalloc(sizeof(struct ubifs_info), GFP_KERNEL);
2127 	if (c) {
2128 		spin_lock_init(&c->cnt_lock);
2129 		spin_lock_init(&c->cs_lock);
2130 		spin_lock_init(&c->buds_lock);
2131 		spin_lock_init(&c->space_lock);
2132 		spin_lock_init(&c->orphan_lock);
2133 		init_rwsem(&c->commit_sem);
2134 		mutex_init(&c->lp_mutex);
2135 		mutex_init(&c->tnc_mutex);
2136 		mutex_init(&c->log_mutex);
2137 		mutex_init(&c->umount_mutex);
2138 		mutex_init(&c->bu_mutex);
2139 		mutex_init(&c->write_reserve_mutex);
2140 		init_waitqueue_head(&c->cmt_wq);
2141 		c->buds = RB_ROOT;
2142 		c->old_idx = RB_ROOT;
2143 		c->size_tree = RB_ROOT;
2144 		c->orph_tree = RB_ROOT;
2145 		INIT_LIST_HEAD(&c->infos_list);
2146 		INIT_LIST_HEAD(&c->idx_gc);
2147 		INIT_LIST_HEAD(&c->replay_list);
2148 		INIT_LIST_HEAD(&c->replay_buds);
2149 		INIT_LIST_HEAD(&c->uncat_list);
2150 		INIT_LIST_HEAD(&c->empty_list);
2151 		INIT_LIST_HEAD(&c->freeable_list);
2152 		INIT_LIST_HEAD(&c->frdi_idx_list);
2153 		INIT_LIST_HEAD(&c->unclean_leb_list);
2154 		INIT_LIST_HEAD(&c->old_buds);
2155 		INIT_LIST_HEAD(&c->orph_list);
2156 		INIT_LIST_HEAD(&c->orph_new);
2157 		c->no_chk_data_crc = 1;
2158 		c->assert_action = ASSACT_RO;
2159 
2160 		c->highest_inum = UBIFS_FIRST_INO;
2161 		c->lhead_lnum = c->ltail_lnum = UBIFS_LOG_LNUM;
2162 
2163 		ubi_get_volume_info(ubi, &c->vi);
2164 		ubi_get_device_info(c->vi.ubi_num, &c->di);
2165 	}
2166 	return c;
2167 }
2168 
2169 static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
2170 {
2171 	struct ubifs_info *c = sb->s_fs_info;
2172 	struct inode *root;
2173 	int err;
2174 
2175 	c->vfs_sb = sb;
2176 	/* Re-open the UBI device in read-write mode */
2177 	c->ubi = ubi_open_volume(c->vi.ubi_num, c->vi.vol_id, UBI_READWRITE);
2178 	if (IS_ERR(c->ubi)) {
2179 		err = PTR_ERR(c->ubi);
2180 		goto out;
2181 	}
2182 
2183 	err = ubifs_parse_options(c, data, 0);
2184 	if (err)
2185 		goto out_close;
2186 
2187 	/*
2188 	 * UBIFS provides 'backing_dev_info' in order to disable read-ahead. For
2189 	 * UBIFS, I/O is not deferred, it is done immediately in readpage,
2190 	 * which means the user would have to wait not just for their own I/O
2191 	 * but the read-ahead I/O as well i.e. completely pointless.
2192 	 *
2193 	 * Read-ahead will be disabled because @sb->s_bdi->ra_pages is 0. Also
2194 	 * @sb->s_bdi->capabilities are initialized to 0 so there won't be any
2195 	 * writeback happening.
2196 	 */
2197 	err = super_setup_bdi_name(sb, "ubifs_%d_%d", c->vi.ubi_num,
2198 				   c->vi.vol_id);
2199 	if (err)
2200 		goto out_close;
2201 	sb->s_bdi->ra_pages = 0;
2202 	sb->s_bdi->io_pages = 0;
2203 
2204 	sb->s_fs_info = c;
2205 	sb->s_magic = UBIFS_SUPER_MAGIC;
2206 	sb->s_blocksize = UBIFS_BLOCK_SIZE;
2207 	sb->s_blocksize_bits = UBIFS_BLOCK_SHIFT;
2208 	sb->s_maxbytes = c->max_inode_sz = key_max_inode_size(c);
2209 	if (c->max_inode_sz > MAX_LFS_FILESIZE)
2210 		sb->s_maxbytes = c->max_inode_sz = MAX_LFS_FILESIZE;
2211 	sb->s_op = &ubifs_super_operations;
2212 	sb->s_xattr = ubifs_xattr_handlers;
2213 	fscrypt_set_ops(sb, &ubifs_crypt_operations);
2214 
2215 	mutex_lock(&c->umount_mutex);
2216 	err = mount_ubifs(c);
2217 	if (err) {
2218 		ubifs_assert(c, err < 0);
2219 		goto out_unlock;
2220 	}
2221 
2222 	/* Read the root inode */
2223 	root = ubifs_iget(sb, UBIFS_ROOT_INO);
2224 	if (IS_ERR(root)) {
2225 		err = PTR_ERR(root);
2226 		goto out_umount;
2227 	}
2228 
2229 	sb->s_root = d_make_root(root);
2230 	if (!sb->s_root) {
2231 		err = -ENOMEM;
2232 		goto out_umount;
2233 	}
2234 
2235 	import_uuid(&sb->s_uuid, c->uuid);
2236 
2237 	mutex_unlock(&c->umount_mutex);
2238 	return 0;
2239 
2240 out_umount:
2241 	ubifs_umount(c);
2242 out_unlock:
2243 	mutex_unlock(&c->umount_mutex);
2244 out_close:
2245 	ubifs_release_options(c);
2246 	ubi_close_volume(c->ubi);
2247 out:
2248 	return err;
2249 }
2250 
2251 static int sb_test(struct super_block *sb, void *data)
2252 {
2253 	struct ubifs_info *c1 = data;
2254 	struct ubifs_info *c = sb->s_fs_info;
2255 
2256 	return c->vi.cdev == c1->vi.cdev;
2257 }
2258 
2259 static int sb_set(struct super_block *sb, void *data)
2260 {
2261 	sb->s_fs_info = data;
2262 	return set_anon_super(sb, NULL);
2263 }
2264 
2265 static struct dentry *ubifs_mount(struct file_system_type *fs_type, int flags,
2266 			const char *name, void *data)
2267 {
2268 	struct ubi_volume_desc *ubi;
2269 	struct ubifs_info *c;
2270 	struct super_block *sb;
2271 	int err;
2272 
2273 	dbg_gen("name %s, flags %#x", name, flags);
2274 
2275 	/*
2276 	 * Get UBI device number and volume ID. Mount it read-only so far
2277 	 * because this might be a new mount point, and UBI allows only one
2278 	 * read-write user at a time.
2279 	 */
2280 	ubi = open_ubi(name, UBI_READONLY);
2281 	if (IS_ERR(ubi)) {
2282 		if (!(flags & SB_SILENT))
2283 			pr_err("UBIFS error (pid: %d): cannot open \"%s\", error %d",
2284 			       current->pid, name, (int)PTR_ERR(ubi));
2285 		return ERR_CAST(ubi);
2286 	}
2287 
2288 	c = alloc_ubifs_info(ubi);
2289 	if (!c) {
2290 		err = -ENOMEM;
2291 		goto out_close;
2292 	}
2293 
2294 	dbg_gen("opened ubi%d_%d", c->vi.ubi_num, c->vi.vol_id);
2295 
2296 	sb = sget(fs_type, sb_test, sb_set, flags, c);
2297 	if (IS_ERR(sb)) {
2298 		err = PTR_ERR(sb);
2299 		kfree(c);
2300 		goto out_close;
2301 	}
2302 
2303 	if (sb->s_root) {
2304 		struct ubifs_info *c1 = sb->s_fs_info;
2305 		kfree(c);
2306 		/* A new mount point for already mounted UBIFS */
2307 		dbg_gen("this ubi volume is already mounted");
2308 		if (!!(flags & SB_RDONLY) != c1->ro_mount) {
2309 			err = -EBUSY;
2310 			goto out_deact;
2311 		}
2312 	} else {
2313 		err = ubifs_fill_super(sb, data, flags & SB_SILENT ? 1 : 0);
2314 		if (err)
2315 			goto out_deact;
2316 		/* We do not support atime */
2317 		sb->s_flags |= SB_ACTIVE;
2318 		if (IS_ENABLED(CONFIG_UBIFS_ATIME_SUPPORT))
2319 			ubifs_msg(c, "full atime support is enabled.");
2320 		else
2321 			sb->s_flags |= SB_NOATIME;
2322 	}
2323 
2324 	/* 'fill_super()' opens ubi again so we must close it here */
2325 	ubi_close_volume(ubi);
2326 
2327 	return dget(sb->s_root);
2328 
2329 out_deact:
2330 	deactivate_locked_super(sb);
2331 out_close:
2332 	ubi_close_volume(ubi);
2333 	return ERR_PTR(err);
2334 }
2335 
2336 static void kill_ubifs_super(struct super_block *s)
2337 {
2338 	struct ubifs_info *c = s->s_fs_info;
2339 	kill_anon_super(s);
2340 	kfree(c);
2341 }
2342 
2343 static struct file_system_type ubifs_fs_type = {
2344 	.name    = "ubifs",
2345 	.owner   = THIS_MODULE,
2346 	.mount   = ubifs_mount,
2347 	.kill_sb = kill_ubifs_super,
2348 };
2349 MODULE_ALIAS_FS("ubifs");
2350 
2351 /*
2352  * Inode slab cache constructor.
2353  */
2354 static void inode_slab_ctor(void *obj)
2355 {
2356 	struct ubifs_inode *ui = obj;
2357 	inode_init_once(&ui->vfs_inode);
2358 }
2359 
2360 static int __init ubifs_init(void)
2361 {
2362 	int err;
2363 
2364 	BUILD_BUG_ON(sizeof(struct ubifs_ch) != 24);
2365 
2366 	/* Make sure node sizes are 8-byte aligned */
2367 	BUILD_BUG_ON(UBIFS_CH_SZ        & 7);
2368 	BUILD_BUG_ON(UBIFS_INO_NODE_SZ  & 7);
2369 	BUILD_BUG_ON(UBIFS_DENT_NODE_SZ & 7);
2370 	BUILD_BUG_ON(UBIFS_XENT_NODE_SZ & 7);
2371 	BUILD_BUG_ON(UBIFS_DATA_NODE_SZ & 7);
2372 	BUILD_BUG_ON(UBIFS_TRUN_NODE_SZ & 7);
2373 	BUILD_BUG_ON(UBIFS_SB_NODE_SZ   & 7);
2374 	BUILD_BUG_ON(UBIFS_MST_NODE_SZ  & 7);
2375 	BUILD_BUG_ON(UBIFS_REF_NODE_SZ  & 7);
2376 	BUILD_BUG_ON(UBIFS_CS_NODE_SZ   & 7);
2377 	BUILD_BUG_ON(UBIFS_ORPH_NODE_SZ & 7);
2378 
2379 	BUILD_BUG_ON(UBIFS_MAX_DENT_NODE_SZ & 7);
2380 	BUILD_BUG_ON(UBIFS_MAX_XENT_NODE_SZ & 7);
2381 	BUILD_BUG_ON(UBIFS_MAX_DATA_NODE_SZ & 7);
2382 	BUILD_BUG_ON(UBIFS_MAX_INO_NODE_SZ  & 7);
2383 	BUILD_BUG_ON(UBIFS_MAX_NODE_SZ      & 7);
2384 	BUILD_BUG_ON(MIN_WRITE_SZ           & 7);
2385 
2386 	/* Check min. node size */
2387 	BUILD_BUG_ON(UBIFS_INO_NODE_SZ  < MIN_WRITE_SZ);
2388 	BUILD_BUG_ON(UBIFS_DENT_NODE_SZ < MIN_WRITE_SZ);
2389 	BUILD_BUG_ON(UBIFS_XENT_NODE_SZ < MIN_WRITE_SZ);
2390 	BUILD_BUG_ON(UBIFS_TRUN_NODE_SZ < MIN_WRITE_SZ);
2391 
2392 	BUILD_BUG_ON(UBIFS_MAX_DENT_NODE_SZ > UBIFS_MAX_NODE_SZ);
2393 	BUILD_BUG_ON(UBIFS_MAX_XENT_NODE_SZ > UBIFS_MAX_NODE_SZ);
2394 	BUILD_BUG_ON(UBIFS_MAX_DATA_NODE_SZ > UBIFS_MAX_NODE_SZ);
2395 	BUILD_BUG_ON(UBIFS_MAX_INO_NODE_SZ  > UBIFS_MAX_NODE_SZ);
2396 
2397 	/* Defined node sizes */
2398 	BUILD_BUG_ON(UBIFS_SB_NODE_SZ  != 4096);
2399 	BUILD_BUG_ON(UBIFS_MST_NODE_SZ != 512);
2400 	BUILD_BUG_ON(UBIFS_INO_NODE_SZ != 160);
2401 	BUILD_BUG_ON(UBIFS_REF_NODE_SZ != 64);
2402 
2403 	/*
2404 	 * We use 2 bit wide bit-fields to store compression type, which should
2405 	 * be amended if more compressors are added. The bit-fields are:
2406 	 * @compr_type in 'struct ubifs_inode', @default_compr in
2407 	 * 'struct ubifs_info' and @compr_type in 'struct ubifs_mount_opts'.
2408 	 */
2409 	BUILD_BUG_ON(UBIFS_COMPR_TYPES_CNT > 4);
2410 
2411 	/*
2412 	 * We require that PAGE_SIZE is greater-than-or-equal-to
2413 	 * UBIFS_BLOCK_SIZE. It is assumed that both are powers of 2.
2414 	 */
2415 	if (PAGE_SIZE < UBIFS_BLOCK_SIZE) {
2416 		pr_err("UBIFS error (pid %d): VFS page cache size is %u bytes, but UBIFS requires at least 4096 bytes",
2417 		       current->pid, (unsigned int)PAGE_SIZE);
2418 		return -EINVAL;
2419 	}
2420 
2421 	ubifs_inode_slab = kmem_cache_create("ubifs_inode_slab",
2422 				sizeof(struct ubifs_inode), 0,
2423 				SLAB_MEM_SPREAD | SLAB_RECLAIM_ACCOUNT |
2424 				SLAB_ACCOUNT, &inode_slab_ctor);
2425 	if (!ubifs_inode_slab)
2426 		return -ENOMEM;
2427 
2428 	err = register_shrinker(&ubifs_shrinker_info);
2429 	if (err)
2430 		goto out_slab;
2431 
2432 	err = ubifs_compressors_init();
2433 	if (err)
2434 		goto out_shrinker;
2435 
2436 	dbg_debugfs_init();
2437 
2438 	err = register_filesystem(&ubifs_fs_type);
2439 	if (err) {
2440 		pr_err("UBIFS error (pid %d): cannot register file system, error %d",
2441 		       current->pid, err);
2442 		goto out_dbg;
2443 	}
2444 	return 0;
2445 
2446 out_dbg:
2447 	dbg_debugfs_exit();
2448 	ubifs_compressors_exit();
2449 out_shrinker:
2450 	unregister_shrinker(&ubifs_shrinker_info);
2451 out_slab:
2452 	kmem_cache_destroy(ubifs_inode_slab);
2453 	return err;
2454 }
2455 /* late_initcall to let compressors initialize first */
2456 late_initcall(ubifs_init);
2457 
2458 static void __exit ubifs_exit(void)
2459 {
2460 	WARN_ON(!list_empty(&ubifs_infos));
2461 	WARN_ON(atomic_long_read(&ubifs_clean_zn_cnt) != 0);
2462 
2463 	dbg_debugfs_exit();
2464 	ubifs_compressors_exit();
2465 	unregister_shrinker(&ubifs_shrinker_info);
2466 
2467 	/*
2468 	 * Make sure all delayed rcu free inodes are flushed before we
2469 	 * destroy cache.
2470 	 */
2471 	rcu_barrier();
2472 	kmem_cache_destroy(ubifs_inode_slab);
2473 	unregister_filesystem(&ubifs_fs_type);
2474 }
2475 module_exit(ubifs_exit);
2476 
2477 MODULE_LICENSE("GPL");
2478 MODULE_VERSION(__stringify(UBIFS_VERSION));
2479 MODULE_AUTHOR("Artem Bityutskiy, Adrian Hunter");
2480 MODULE_DESCRIPTION("UBIFS - UBI File System");
2481