xref: /openbmc/linux/fs/ubifs/super.c (revision 9ac8d3fb)
1 /*
2  * This file is part of UBIFS.
3  *
4  * Copyright (C) 2006-2008 Nokia Corporation.
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  */
22 
23 /*
24  * This file implements UBIFS initialization and VFS superblock operations. Some
25  * initialization stuff which is rather large and complex is placed at
26  * corresponding subsystems, but most of it is here.
27  */
28 
29 #include <linux/init.h>
30 #include <linux/slab.h>
31 #include <linux/module.h>
32 #include <linux/ctype.h>
33 #include <linux/kthread.h>
34 #include <linux/parser.h>
35 #include <linux/seq_file.h>
36 #include <linux/mount.h>
37 #include "ubifs.h"
38 
39 /* Slab cache for UBIFS inodes */
40 struct kmem_cache *ubifs_inode_slab;
41 
42 /* UBIFS TNC shrinker description */
43 static struct shrinker ubifs_shrinker_info = {
44 	.shrink = ubifs_shrinker,
45 	.seeks = DEFAULT_SEEKS,
46 };
47 
48 /**
49  * validate_inode - validate inode.
50  * @c: UBIFS file-system description object
51  * @inode: the inode to validate
52  *
53  * This is a helper function for 'ubifs_iget()' which validates various fields
54  * of a newly built inode to make sure they contain sane values and prevent
55  * possible vulnerabilities. Returns zero if the inode is all right and
56  * a non-zero error code if not.
57  */
58 static int validate_inode(struct ubifs_info *c, const struct inode *inode)
59 {
60 	int err;
61 	const struct ubifs_inode *ui = ubifs_inode(inode);
62 
63 	if (inode->i_size > c->max_inode_sz) {
64 		ubifs_err("inode is too large (%lld)",
65 			  (long long)inode->i_size);
66 		return 1;
67 	}
68 
69 	if (ui->compr_type < 0 || ui->compr_type >= UBIFS_COMPR_TYPES_CNT) {
70 		ubifs_err("unknown compression type %d", ui->compr_type);
71 		return 2;
72 	}
73 
74 	if (ui->xattr_names + ui->xattr_cnt > XATTR_LIST_MAX)
75 		return 3;
76 
77 	if (ui->data_len < 0 || ui->data_len > UBIFS_MAX_INO_DATA)
78 		return 4;
79 
80 	if (ui->xattr && (inode->i_mode & S_IFMT) != S_IFREG)
81 		return 5;
82 
83 	if (!ubifs_compr_present(ui->compr_type)) {
84 		ubifs_warn("inode %lu uses '%s' compression, but it was not "
85 			   "compiled in", inode->i_ino,
86 			   ubifs_compr_name(ui->compr_type));
87 	}
88 
89 	err = dbg_check_dir_size(c, inode);
90 	return err;
91 }
92 
93 struct inode *ubifs_iget(struct super_block *sb, unsigned long inum)
94 {
95 	int err;
96 	union ubifs_key key;
97 	struct ubifs_ino_node *ino;
98 	struct ubifs_info *c = sb->s_fs_info;
99 	struct inode *inode;
100 	struct ubifs_inode *ui;
101 
102 	dbg_gen("inode %lu", inum);
103 
104 	inode = iget_locked(sb, inum);
105 	if (!inode)
106 		return ERR_PTR(-ENOMEM);
107 	if (!(inode->i_state & I_NEW))
108 		return inode;
109 	ui = ubifs_inode(inode);
110 
111 	ino = kmalloc(UBIFS_MAX_INO_NODE_SZ, GFP_NOFS);
112 	if (!ino) {
113 		err = -ENOMEM;
114 		goto out;
115 	}
116 
117 	ino_key_init(c, &key, inode->i_ino);
118 
119 	err = ubifs_tnc_lookup(c, &key, ino);
120 	if (err)
121 		goto out_ino;
122 
123 	inode->i_flags |= (S_NOCMTIME | S_NOATIME);
124 	inode->i_nlink = le32_to_cpu(ino->nlink);
125 	inode->i_uid   = le32_to_cpu(ino->uid);
126 	inode->i_gid   = le32_to_cpu(ino->gid);
127 	inode->i_atime.tv_sec  = (int64_t)le64_to_cpu(ino->atime_sec);
128 	inode->i_atime.tv_nsec = le32_to_cpu(ino->atime_nsec);
129 	inode->i_mtime.tv_sec  = (int64_t)le64_to_cpu(ino->mtime_sec);
130 	inode->i_mtime.tv_nsec = le32_to_cpu(ino->mtime_nsec);
131 	inode->i_ctime.tv_sec  = (int64_t)le64_to_cpu(ino->ctime_sec);
132 	inode->i_ctime.tv_nsec = le32_to_cpu(ino->ctime_nsec);
133 	inode->i_mode = le32_to_cpu(ino->mode);
134 	inode->i_size = le64_to_cpu(ino->size);
135 
136 	ui->data_len    = le32_to_cpu(ino->data_len);
137 	ui->flags       = le32_to_cpu(ino->flags);
138 	ui->compr_type  = le16_to_cpu(ino->compr_type);
139 	ui->creat_sqnum = le64_to_cpu(ino->creat_sqnum);
140 	ui->xattr_cnt   = le32_to_cpu(ino->xattr_cnt);
141 	ui->xattr_size  = le32_to_cpu(ino->xattr_size);
142 	ui->xattr_names = le32_to_cpu(ino->xattr_names);
143 	ui->synced_i_size = ui->ui_size = inode->i_size;
144 
145 	ui->xattr = (ui->flags & UBIFS_XATTR_FL) ? 1 : 0;
146 
147 	err = validate_inode(c, inode);
148 	if (err)
149 		goto out_invalid;
150 
151 	/* Disable read-ahead */
152 	inode->i_mapping->backing_dev_info = &c->bdi;
153 
154 	switch (inode->i_mode & S_IFMT) {
155 	case S_IFREG:
156 		inode->i_mapping->a_ops = &ubifs_file_address_operations;
157 		inode->i_op = &ubifs_file_inode_operations;
158 		inode->i_fop = &ubifs_file_operations;
159 		if (ui->xattr) {
160 			ui->data = kmalloc(ui->data_len + 1, GFP_NOFS);
161 			if (!ui->data) {
162 				err = -ENOMEM;
163 				goto out_ino;
164 			}
165 			memcpy(ui->data, ino->data, ui->data_len);
166 			((char *)ui->data)[ui->data_len] = '\0';
167 		} else if (ui->data_len != 0) {
168 			err = 10;
169 			goto out_invalid;
170 		}
171 		break;
172 	case S_IFDIR:
173 		inode->i_op  = &ubifs_dir_inode_operations;
174 		inode->i_fop = &ubifs_dir_operations;
175 		if (ui->data_len != 0) {
176 			err = 11;
177 			goto out_invalid;
178 		}
179 		break;
180 	case S_IFLNK:
181 		inode->i_op = &ubifs_symlink_inode_operations;
182 		if (ui->data_len <= 0 || ui->data_len > UBIFS_MAX_INO_DATA) {
183 			err = 12;
184 			goto out_invalid;
185 		}
186 		ui->data = kmalloc(ui->data_len + 1, GFP_NOFS);
187 		if (!ui->data) {
188 			err = -ENOMEM;
189 			goto out_ino;
190 		}
191 		memcpy(ui->data, ino->data, ui->data_len);
192 		((char *)ui->data)[ui->data_len] = '\0';
193 		break;
194 	case S_IFBLK:
195 	case S_IFCHR:
196 	{
197 		dev_t rdev;
198 		union ubifs_dev_desc *dev;
199 
200 		ui->data = kmalloc(sizeof(union ubifs_dev_desc), GFP_NOFS);
201 		if (!ui->data) {
202 			err = -ENOMEM;
203 			goto out_ino;
204 		}
205 
206 		dev = (union ubifs_dev_desc *)ino->data;
207 		if (ui->data_len == sizeof(dev->new))
208 			rdev = new_decode_dev(le32_to_cpu(dev->new));
209 		else if (ui->data_len == sizeof(dev->huge))
210 			rdev = huge_decode_dev(le64_to_cpu(dev->huge));
211 		else {
212 			err = 13;
213 			goto out_invalid;
214 		}
215 		memcpy(ui->data, ino->data, ui->data_len);
216 		inode->i_op = &ubifs_file_inode_operations;
217 		init_special_inode(inode, inode->i_mode, rdev);
218 		break;
219 	}
220 	case S_IFSOCK:
221 	case S_IFIFO:
222 		inode->i_op = &ubifs_file_inode_operations;
223 		init_special_inode(inode, inode->i_mode, 0);
224 		if (ui->data_len != 0) {
225 			err = 14;
226 			goto out_invalid;
227 		}
228 		break;
229 	default:
230 		err = 15;
231 		goto out_invalid;
232 	}
233 
234 	kfree(ino);
235 	ubifs_set_inode_flags(inode);
236 	unlock_new_inode(inode);
237 	return inode;
238 
239 out_invalid:
240 	ubifs_err("inode %lu validation failed, error %d", inode->i_ino, err);
241 	dbg_dump_node(c, ino);
242 	dbg_dump_inode(c, inode);
243 	err = -EINVAL;
244 out_ino:
245 	kfree(ino);
246 out:
247 	ubifs_err("failed to read inode %lu, error %d", inode->i_ino, err);
248 	iget_failed(inode);
249 	return ERR_PTR(err);
250 }
251 
252 static struct inode *ubifs_alloc_inode(struct super_block *sb)
253 {
254 	struct ubifs_inode *ui;
255 
256 	ui = kmem_cache_alloc(ubifs_inode_slab, GFP_NOFS);
257 	if (!ui)
258 		return NULL;
259 
260 	memset((void *)ui + sizeof(struct inode), 0,
261 	       sizeof(struct ubifs_inode) - sizeof(struct inode));
262 	mutex_init(&ui->ui_mutex);
263 	spin_lock_init(&ui->ui_lock);
264 	return &ui->vfs_inode;
265 };
266 
267 static void ubifs_destroy_inode(struct inode *inode)
268 {
269 	struct ubifs_inode *ui = ubifs_inode(inode);
270 
271 	kfree(ui->data);
272 	kmem_cache_free(ubifs_inode_slab, inode);
273 }
274 
275 /*
276  * Note, Linux write-back code calls this without 'i_mutex'.
277  */
278 static int ubifs_write_inode(struct inode *inode, int wait)
279 {
280 	int err = 0;
281 	struct ubifs_info *c = inode->i_sb->s_fs_info;
282 	struct ubifs_inode *ui = ubifs_inode(inode);
283 
284 	ubifs_assert(!ui->xattr);
285 	if (is_bad_inode(inode))
286 		return 0;
287 
288 	mutex_lock(&ui->ui_mutex);
289 	/*
290 	 * Due to races between write-back forced by budgeting
291 	 * (see 'sync_some_inodes()') and pdflush write-back, the inode may
292 	 * have already been synchronized, do not do this again. This might
293 	 * also happen if it was synchronized in an VFS operation, e.g.
294 	 * 'ubifs_link()'.
295 	 */
296 	if (!ui->dirty) {
297 		mutex_unlock(&ui->ui_mutex);
298 		return 0;
299 	}
300 
301 	/*
302 	 * As an optimization, do not write orphan inodes to the media just
303 	 * because this is not needed.
304 	 */
305 	dbg_gen("inode %lu, mode %#x, nlink %u",
306 		inode->i_ino, (int)inode->i_mode, inode->i_nlink);
307 	if (inode->i_nlink) {
308 		err = ubifs_jnl_write_inode(c, inode);
309 		if (err)
310 			ubifs_err("can't write inode %lu, error %d",
311 				  inode->i_ino, err);
312 	}
313 
314 	ui->dirty = 0;
315 	mutex_unlock(&ui->ui_mutex);
316 	ubifs_release_dirty_inode_budget(c, ui);
317 	return err;
318 }
319 
320 static void ubifs_delete_inode(struct inode *inode)
321 {
322 	int err;
323 	struct ubifs_info *c = inode->i_sb->s_fs_info;
324 	struct ubifs_inode *ui = ubifs_inode(inode);
325 
326 	if (ui->xattr)
327 		/*
328 		 * Extended attribute inode deletions are fully handled in
329 		 * 'ubifs_removexattr()'. These inodes are special and have
330 		 * limited usage, so there is nothing to do here.
331 		 */
332 		goto out;
333 
334 	dbg_gen("inode %lu, mode %#x", inode->i_ino, (int)inode->i_mode);
335 	ubifs_assert(!atomic_read(&inode->i_count));
336 	ubifs_assert(inode->i_nlink == 0);
337 
338 	truncate_inode_pages(&inode->i_data, 0);
339 	if (is_bad_inode(inode))
340 		goto out;
341 
342 	ui->ui_size = inode->i_size = 0;
343 	err = ubifs_jnl_delete_inode(c, inode);
344 	if (err)
345 		/*
346 		 * Worst case we have a lost orphan inode wasting space, so a
347 		 * simple error message is OK here.
348 		 */
349 		ubifs_err("can't delete inode %lu, error %d",
350 			  inode->i_ino, err);
351 
352 out:
353 	if (ui->dirty)
354 		ubifs_release_dirty_inode_budget(c, ui);
355 	clear_inode(inode);
356 }
357 
358 static void ubifs_dirty_inode(struct inode *inode)
359 {
360 	struct ubifs_inode *ui = ubifs_inode(inode);
361 
362 	ubifs_assert(mutex_is_locked(&ui->ui_mutex));
363 	if (!ui->dirty) {
364 		ui->dirty = 1;
365 		dbg_gen("inode %lu",  inode->i_ino);
366 	}
367 }
368 
369 static int ubifs_statfs(struct dentry *dentry, struct kstatfs *buf)
370 {
371 	struct ubifs_info *c = dentry->d_sb->s_fs_info;
372 	unsigned long long free;
373 	__le32 *uuid = (__le32 *)c->uuid;
374 
375 	free = ubifs_get_free_space(c);
376 	dbg_gen("free space %lld bytes (%lld blocks)",
377 		free, free >> UBIFS_BLOCK_SHIFT);
378 
379 	buf->f_type = UBIFS_SUPER_MAGIC;
380 	buf->f_bsize = UBIFS_BLOCK_SIZE;
381 	buf->f_blocks = c->block_cnt;
382 	buf->f_bfree = free >> UBIFS_BLOCK_SHIFT;
383 	if (free > c->report_rp_size)
384 		buf->f_bavail = (free - c->report_rp_size) >> UBIFS_BLOCK_SHIFT;
385 	else
386 		buf->f_bavail = 0;
387 	buf->f_files = 0;
388 	buf->f_ffree = 0;
389 	buf->f_namelen = UBIFS_MAX_NLEN;
390 	buf->f_fsid.val[0] = le32_to_cpu(uuid[0]) ^ le32_to_cpu(uuid[2]);
391 	buf->f_fsid.val[1] = le32_to_cpu(uuid[1]) ^ le32_to_cpu(uuid[3]);
392 	return 0;
393 }
394 
395 static int ubifs_show_options(struct seq_file *s, struct vfsmount *mnt)
396 {
397 	struct ubifs_info *c = mnt->mnt_sb->s_fs_info;
398 
399 	if (c->mount_opts.unmount_mode == 2)
400 		seq_printf(s, ",fast_unmount");
401 	else if (c->mount_opts.unmount_mode == 1)
402 		seq_printf(s, ",norm_unmount");
403 
404 	if (c->mount_opts.bulk_read == 2)
405 		seq_printf(s, ",bulk_read");
406 	else if (c->mount_opts.bulk_read == 1)
407 		seq_printf(s, ",no_bulk_read");
408 
409 	if (c->mount_opts.chk_data_crc == 2)
410 		seq_printf(s, ",chk_data_crc");
411 	else if (c->mount_opts.chk_data_crc == 1)
412 		seq_printf(s, ",no_chk_data_crc");
413 
414 	return 0;
415 }
416 
417 static int ubifs_sync_fs(struct super_block *sb, int wait)
418 {
419 	struct ubifs_info *c = sb->s_fs_info;
420 	int i, ret = 0, err;
421 	long long bud_bytes;
422 
423 	if (c->jheads) {
424 		for (i = 0; i < c->jhead_cnt; i++) {
425 			err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
426 			if (err && !ret)
427 				ret = err;
428 		}
429 
430 		/* Commit the journal unless it has too little data */
431 		spin_lock(&c->buds_lock);
432 		bud_bytes = c->bud_bytes;
433 		spin_unlock(&c->buds_lock);
434 		if (bud_bytes > c->leb_size) {
435 			err = ubifs_run_commit(c);
436 			if (err)
437 				return err;
438 		}
439 	}
440 
441 	/*
442 	 * We ought to call sync for c->ubi but it does not have one. If it had
443 	 * it would in turn call mtd->sync, however mtd operations are
444 	 * synchronous anyway, so we don't lose any sleep here.
445 	 */
446 	return ret;
447 }
448 
449 /**
450  * init_constants_early - initialize UBIFS constants.
451  * @c: UBIFS file-system description object
452  *
453  * This function initialize UBIFS constants which do not need the superblock to
454  * be read. It also checks that the UBI volume satisfies basic UBIFS
455  * requirements. Returns zero in case of success and a negative error code in
456  * case of failure.
457  */
458 static int init_constants_early(struct ubifs_info *c)
459 {
460 	if (c->vi.corrupted) {
461 		ubifs_warn("UBI volume is corrupted - read-only mode");
462 		c->ro_media = 1;
463 	}
464 
465 	if (c->di.ro_mode) {
466 		ubifs_msg("read-only UBI device");
467 		c->ro_media = 1;
468 	}
469 
470 	if (c->vi.vol_type == UBI_STATIC_VOLUME) {
471 		ubifs_msg("static UBI volume - read-only mode");
472 		c->ro_media = 1;
473 	}
474 
475 	c->leb_cnt = c->vi.size;
476 	c->leb_size = c->vi.usable_leb_size;
477 	c->half_leb_size = c->leb_size / 2;
478 	c->min_io_size = c->di.min_io_size;
479 	c->min_io_shift = fls(c->min_io_size) - 1;
480 
481 	if (c->leb_size < UBIFS_MIN_LEB_SZ) {
482 		ubifs_err("too small LEBs (%d bytes), min. is %d bytes",
483 			  c->leb_size, UBIFS_MIN_LEB_SZ);
484 		return -EINVAL;
485 	}
486 
487 	if (c->leb_cnt < UBIFS_MIN_LEB_CNT) {
488 		ubifs_err("too few LEBs (%d), min. is %d",
489 			  c->leb_cnt, UBIFS_MIN_LEB_CNT);
490 		return -EINVAL;
491 	}
492 
493 	if (!is_power_of_2(c->min_io_size)) {
494 		ubifs_err("bad min. I/O size %d", c->min_io_size);
495 		return -EINVAL;
496 	}
497 
498 	/*
499 	 * UBIFS aligns all node to 8-byte boundary, so to make function in
500 	 * io.c simpler, assume minimum I/O unit size to be 8 bytes if it is
501 	 * less than 8.
502 	 */
503 	if (c->min_io_size < 8) {
504 		c->min_io_size = 8;
505 		c->min_io_shift = 3;
506 	}
507 
508 	c->ref_node_alsz = ALIGN(UBIFS_REF_NODE_SZ, c->min_io_size);
509 	c->mst_node_alsz = ALIGN(UBIFS_MST_NODE_SZ, c->min_io_size);
510 
511 	/*
512 	 * Initialize node length ranges which are mostly needed for node
513 	 * length validation.
514 	 */
515 	c->ranges[UBIFS_PAD_NODE].len  = UBIFS_PAD_NODE_SZ;
516 	c->ranges[UBIFS_SB_NODE].len   = UBIFS_SB_NODE_SZ;
517 	c->ranges[UBIFS_MST_NODE].len  = UBIFS_MST_NODE_SZ;
518 	c->ranges[UBIFS_REF_NODE].len  = UBIFS_REF_NODE_SZ;
519 	c->ranges[UBIFS_TRUN_NODE].len = UBIFS_TRUN_NODE_SZ;
520 	c->ranges[UBIFS_CS_NODE].len   = UBIFS_CS_NODE_SZ;
521 
522 	c->ranges[UBIFS_INO_NODE].min_len  = UBIFS_INO_NODE_SZ;
523 	c->ranges[UBIFS_INO_NODE].max_len  = UBIFS_MAX_INO_NODE_SZ;
524 	c->ranges[UBIFS_ORPH_NODE].min_len =
525 				UBIFS_ORPH_NODE_SZ + sizeof(__le64);
526 	c->ranges[UBIFS_ORPH_NODE].max_len = c->leb_size;
527 	c->ranges[UBIFS_DENT_NODE].min_len = UBIFS_DENT_NODE_SZ;
528 	c->ranges[UBIFS_DENT_NODE].max_len = UBIFS_MAX_DENT_NODE_SZ;
529 	c->ranges[UBIFS_XENT_NODE].min_len = UBIFS_XENT_NODE_SZ;
530 	c->ranges[UBIFS_XENT_NODE].max_len = UBIFS_MAX_XENT_NODE_SZ;
531 	c->ranges[UBIFS_DATA_NODE].min_len = UBIFS_DATA_NODE_SZ;
532 	c->ranges[UBIFS_DATA_NODE].max_len = UBIFS_MAX_DATA_NODE_SZ;
533 	/*
534 	 * Minimum indexing node size is amended later when superblock is
535 	 * read and the key length is known.
536 	 */
537 	c->ranges[UBIFS_IDX_NODE].min_len = UBIFS_IDX_NODE_SZ + UBIFS_BRANCH_SZ;
538 	/*
539 	 * Maximum indexing node size is amended later when superblock is
540 	 * read and the fanout is known.
541 	 */
542 	c->ranges[UBIFS_IDX_NODE].max_len = INT_MAX;
543 
544 	/*
545 	 * Initialize dead and dark LEB space watermarks.
546 	 *
547 	 * Dead space is the space which cannot be used. Its watermark is
548 	 * equivalent to min. I/O unit or minimum node size if it is greater
549 	 * then min. I/O unit.
550 	 *
551 	 * Dark space is the space which might be used, or might not, depending
552 	 * on which node should be written to the LEB. Its watermark is
553 	 * equivalent to maximum UBIFS node size.
554 	 */
555 	c->dead_wm = ALIGN(MIN_WRITE_SZ, c->min_io_size);
556 	c->dark_wm = ALIGN(UBIFS_MAX_NODE_SZ, c->min_io_size);
557 
558 	/*
559 	 * Calculate how many bytes would be wasted at the end of LEB if it was
560 	 * fully filled with data nodes of maximum size. This is used in
561 	 * calculations when reporting free space.
562 	 */
563 	c->leb_overhead = c->leb_size % UBIFS_MAX_DATA_NODE_SZ;
564 	/* Buffer size for bulk-reads */
565 	c->bulk_read_buf_size = UBIFS_MAX_BULK_READ * UBIFS_MAX_DATA_NODE_SZ;
566 	if (c->bulk_read_buf_size > c->leb_size)
567 		c->bulk_read_buf_size = c->leb_size;
568 	if (c->bulk_read_buf_size > 128 * 1024) {
569 		/* Check if we can kmalloc more than 128KiB */
570 		void *try = kmalloc(c->bulk_read_buf_size, GFP_KERNEL);
571 
572 		kfree(try);
573 		if (!try)
574 			c->bulk_read_buf_size = 128 * 1024;
575 	}
576 	return 0;
577 }
578 
579 /**
580  * bud_wbuf_callback - bud LEB write-buffer synchronization call-back.
581  * @c: UBIFS file-system description object
582  * @lnum: LEB the write-buffer was synchronized to
583  * @free: how many free bytes left in this LEB
584  * @pad: how many bytes were padded
585  *
586  * This is a callback function which is called by the I/O unit when the
587  * write-buffer is synchronized. We need this to correctly maintain space
588  * accounting in bud logical eraseblocks. This function returns zero in case of
589  * success and a negative error code in case of failure.
590  *
591  * This function actually belongs to the journal, but we keep it here because
592  * we want to keep it static.
593  */
594 static int bud_wbuf_callback(struct ubifs_info *c, int lnum, int free, int pad)
595 {
596 	return ubifs_update_one_lp(c, lnum, free, pad, 0, 0);
597 }
598 
599 /*
600  * init_constants_late - initialize UBIFS constants.
601  * @c: UBIFS file-system description object
602  *
603  * This is a helper function which initializes various UBIFS constants after
604  * the superblock has been read. It also checks various UBIFS parameters and
605  * makes sure they are all right. Returns zero in case of success and a
606  * negative error code in case of failure.
607  */
608 static int init_constants_late(struct ubifs_info *c)
609 {
610 	int tmp, err;
611 	uint64_t tmp64;
612 
613 	c->main_bytes = (long long)c->main_lebs * c->leb_size;
614 	c->max_znode_sz = sizeof(struct ubifs_znode) +
615 				c->fanout * sizeof(struct ubifs_zbranch);
616 
617 	tmp = ubifs_idx_node_sz(c, 1);
618 	c->ranges[UBIFS_IDX_NODE].min_len = tmp;
619 	c->min_idx_node_sz = ALIGN(tmp, 8);
620 
621 	tmp = ubifs_idx_node_sz(c, c->fanout);
622 	c->ranges[UBIFS_IDX_NODE].max_len = tmp;
623 	c->max_idx_node_sz = ALIGN(tmp, 8);
624 
625 	/* Make sure LEB size is large enough to fit full commit */
626 	tmp = UBIFS_CS_NODE_SZ + UBIFS_REF_NODE_SZ * c->jhead_cnt;
627 	tmp = ALIGN(tmp, c->min_io_size);
628 	if (tmp > c->leb_size) {
629 		dbg_err("too small LEB size %d, at least %d needed",
630 			c->leb_size, tmp);
631 		return -EINVAL;
632 	}
633 
634 	/*
635 	 * Make sure that the log is large enough to fit reference nodes for
636 	 * all buds plus one reserved LEB.
637 	 */
638 	tmp64 = c->max_bud_bytes;
639 	tmp = do_div(tmp64, c->leb_size);
640 	c->max_bud_cnt = tmp64 + !!tmp;
641 	tmp = (c->ref_node_alsz * c->max_bud_cnt + c->leb_size - 1);
642 	tmp /= c->leb_size;
643 	tmp += 1;
644 	if (c->log_lebs < tmp) {
645 		dbg_err("too small log %d LEBs, required min. %d LEBs",
646 			c->log_lebs, tmp);
647 		return -EINVAL;
648 	}
649 
650 	/*
651 	 * When budgeting we assume worst-case scenarios when the pages are not
652 	 * be compressed and direntries are of the maximum size.
653 	 *
654 	 * Note, data, which may be stored in inodes is budgeted separately, so
655 	 * it is not included into 'c->inode_budget'.
656 	 */
657 	c->page_budget = UBIFS_MAX_DATA_NODE_SZ * UBIFS_BLOCKS_PER_PAGE;
658 	c->inode_budget = UBIFS_INO_NODE_SZ;
659 	c->dent_budget = UBIFS_MAX_DENT_NODE_SZ;
660 
661 	/*
662 	 * When the amount of flash space used by buds becomes
663 	 * 'c->max_bud_bytes', UBIFS just blocks all writers and starts commit.
664 	 * The writers are unblocked when the commit is finished. To avoid
665 	 * writers to be blocked UBIFS initiates background commit in advance,
666 	 * when number of bud bytes becomes above the limit defined below.
667 	 */
668 	c->bg_bud_bytes = (c->max_bud_bytes * 13) >> 4;
669 
670 	/*
671 	 * Ensure minimum journal size. All the bytes in the journal heads are
672 	 * considered to be used, when calculating the current journal usage.
673 	 * Consequently, if the journal is too small, UBIFS will treat it as
674 	 * always full.
675 	 */
676 	tmp64 = (uint64_t)(c->jhead_cnt + 1) * c->leb_size + 1;
677 	if (c->bg_bud_bytes < tmp64)
678 		c->bg_bud_bytes = tmp64;
679 	if (c->max_bud_bytes < tmp64 + c->leb_size)
680 		c->max_bud_bytes = tmp64 + c->leb_size;
681 
682 	err = ubifs_calc_lpt_geom(c);
683 	if (err)
684 		return err;
685 
686 	c->min_idx_lebs = ubifs_calc_min_idx_lebs(c);
687 
688 	/*
689 	 * Calculate total amount of FS blocks. This number is not used
690 	 * internally because it does not make much sense for UBIFS, but it is
691 	 * necessary to report something for the 'statfs()' call.
692 	 *
693 	 * Subtract the LEB reserved for GC, the LEB which is reserved for
694 	 * deletions, and assume only one journal head is available.
695 	 */
696 	tmp64 = c->main_lebs - 2 - c->jhead_cnt + 1;
697 	tmp64 *= (uint64_t)c->leb_size - c->leb_overhead;
698 	tmp64 = ubifs_reported_space(c, tmp64);
699 	c->block_cnt = tmp64 >> UBIFS_BLOCK_SHIFT;
700 
701 	return 0;
702 }
703 
704 /**
705  * take_gc_lnum - reserve GC LEB.
706  * @c: UBIFS file-system description object
707  *
708  * This function ensures that the LEB reserved for garbage collection is
709  * unmapped and is marked as "taken" in lprops. We also have to set free space
710  * to LEB size and dirty space to zero, because lprops may contain out-of-date
711  * information if the file-system was un-mounted before it has been committed.
712  * This function returns zero in case of success and a negative error code in
713  * case of failure.
714  */
715 static int take_gc_lnum(struct ubifs_info *c)
716 {
717 	int err;
718 
719 	if (c->gc_lnum == -1) {
720 		ubifs_err("no LEB for GC");
721 		return -EINVAL;
722 	}
723 
724 	err = ubifs_leb_unmap(c, c->gc_lnum);
725 	if (err)
726 		return err;
727 
728 	/* And we have to tell lprops that this LEB is taken */
729 	err = ubifs_change_one_lp(c, c->gc_lnum, c->leb_size, 0,
730 				  LPROPS_TAKEN, 0, 0);
731 	return err;
732 }
733 
734 /**
735  * alloc_wbufs - allocate write-buffers.
736  * @c: UBIFS file-system description object
737  *
738  * This helper function allocates and initializes UBIFS write-buffers. Returns
739  * zero in case of success and %-ENOMEM in case of failure.
740  */
741 static int alloc_wbufs(struct ubifs_info *c)
742 {
743 	int i, err;
744 
745 	c->jheads = kzalloc(c->jhead_cnt * sizeof(struct ubifs_jhead),
746 			   GFP_KERNEL);
747 	if (!c->jheads)
748 		return -ENOMEM;
749 
750 	/* Initialize journal heads */
751 	for (i = 0; i < c->jhead_cnt; i++) {
752 		INIT_LIST_HEAD(&c->jheads[i].buds_list);
753 		err = ubifs_wbuf_init(c, &c->jheads[i].wbuf);
754 		if (err)
755 			return err;
756 
757 		c->jheads[i].wbuf.sync_callback = &bud_wbuf_callback;
758 		c->jheads[i].wbuf.jhead = i;
759 	}
760 
761 	c->jheads[BASEHD].wbuf.dtype = UBI_SHORTTERM;
762 	/*
763 	 * Garbage Collector head likely contains long-term data and
764 	 * does not need to be synchronized by timer.
765 	 */
766 	c->jheads[GCHD].wbuf.dtype = UBI_LONGTERM;
767 	c->jheads[GCHD].wbuf.timeout = 0;
768 
769 	return 0;
770 }
771 
772 /**
773  * free_wbufs - free write-buffers.
774  * @c: UBIFS file-system description object
775  */
776 static void free_wbufs(struct ubifs_info *c)
777 {
778 	int i;
779 
780 	if (c->jheads) {
781 		for (i = 0; i < c->jhead_cnt; i++) {
782 			kfree(c->jheads[i].wbuf.buf);
783 			kfree(c->jheads[i].wbuf.inodes);
784 		}
785 		kfree(c->jheads);
786 		c->jheads = NULL;
787 	}
788 }
789 
790 /**
791  * free_orphans - free orphans.
792  * @c: UBIFS file-system description object
793  */
794 static void free_orphans(struct ubifs_info *c)
795 {
796 	struct ubifs_orphan *orph;
797 
798 	while (c->orph_dnext) {
799 		orph = c->orph_dnext;
800 		c->orph_dnext = orph->dnext;
801 		list_del(&orph->list);
802 		kfree(orph);
803 	}
804 
805 	while (!list_empty(&c->orph_list)) {
806 		orph = list_entry(c->orph_list.next, struct ubifs_orphan, list);
807 		list_del(&orph->list);
808 		kfree(orph);
809 		dbg_err("orphan list not empty at unmount");
810 	}
811 
812 	vfree(c->orph_buf);
813 	c->orph_buf = NULL;
814 }
815 
816 /**
817  * free_buds - free per-bud objects.
818  * @c: UBIFS file-system description object
819  */
820 static void free_buds(struct ubifs_info *c)
821 {
822 	struct rb_node *this = c->buds.rb_node;
823 	struct ubifs_bud *bud;
824 
825 	while (this) {
826 		if (this->rb_left)
827 			this = this->rb_left;
828 		else if (this->rb_right)
829 			this = this->rb_right;
830 		else {
831 			bud = rb_entry(this, struct ubifs_bud, rb);
832 			this = rb_parent(this);
833 			if (this) {
834 				if (this->rb_left == &bud->rb)
835 					this->rb_left = NULL;
836 				else
837 					this->rb_right = NULL;
838 			}
839 			kfree(bud);
840 		}
841 	}
842 }
843 
844 /**
845  * check_volume_empty - check if the UBI volume is empty.
846  * @c: UBIFS file-system description object
847  *
848  * This function checks if the UBIFS volume is empty by looking if its LEBs are
849  * mapped or not. The result of checking is stored in the @c->empty variable.
850  * Returns zero in case of success and a negative error code in case of
851  * failure.
852  */
853 static int check_volume_empty(struct ubifs_info *c)
854 {
855 	int lnum, err;
856 
857 	c->empty = 1;
858 	for (lnum = 0; lnum < c->leb_cnt; lnum++) {
859 		err = ubi_is_mapped(c->ubi, lnum);
860 		if (unlikely(err < 0))
861 			return err;
862 		if (err == 1) {
863 			c->empty = 0;
864 			break;
865 		}
866 
867 		cond_resched();
868 	}
869 
870 	return 0;
871 }
872 
873 /*
874  * UBIFS mount options.
875  *
876  * Opt_fast_unmount: do not run a journal commit before un-mounting
877  * Opt_norm_unmount: run a journal commit before un-mounting
878  * Opt_bulk_read: enable bulk-reads
879  * Opt_no_bulk_read: disable bulk-reads
880  * Opt_chk_data_crc: check CRCs when reading data nodes
881  * Opt_no_chk_data_crc: do not check CRCs when reading data nodes
882  * Opt_err: just end of array marker
883  */
884 enum {
885 	Opt_fast_unmount,
886 	Opt_norm_unmount,
887 	Opt_bulk_read,
888 	Opt_no_bulk_read,
889 	Opt_chk_data_crc,
890 	Opt_no_chk_data_crc,
891 	Opt_err,
892 };
893 
894 static const match_table_t tokens = {
895 	{Opt_fast_unmount, "fast_unmount"},
896 	{Opt_norm_unmount, "norm_unmount"},
897 	{Opt_bulk_read, "bulk_read"},
898 	{Opt_no_bulk_read, "no_bulk_read"},
899 	{Opt_chk_data_crc, "chk_data_crc"},
900 	{Opt_no_chk_data_crc, "no_chk_data_crc"},
901 	{Opt_err, NULL},
902 };
903 
904 /**
905  * ubifs_parse_options - parse mount parameters.
906  * @c: UBIFS file-system description object
907  * @options: parameters to parse
908  * @is_remount: non-zero if this is FS re-mount
909  *
910  * This function parses UBIFS mount options and returns zero in case success
911  * and a negative error code in case of failure.
912  */
913 static int ubifs_parse_options(struct ubifs_info *c, char *options,
914 			       int is_remount)
915 {
916 	char *p;
917 	substring_t args[MAX_OPT_ARGS];
918 
919 	if (!options)
920 		return 0;
921 
922 	while ((p = strsep(&options, ","))) {
923 		int token;
924 
925 		if (!*p)
926 			continue;
927 
928 		token = match_token(p, tokens, args);
929 		switch (token) {
930 		case Opt_fast_unmount:
931 			c->mount_opts.unmount_mode = 2;
932 			c->fast_unmount = 1;
933 			break;
934 		case Opt_norm_unmount:
935 			c->mount_opts.unmount_mode = 1;
936 			c->fast_unmount = 0;
937 			break;
938 		case Opt_bulk_read:
939 			c->mount_opts.bulk_read = 2;
940 			c->bulk_read = 1;
941 			break;
942 		case Opt_no_bulk_read:
943 			c->mount_opts.bulk_read = 1;
944 			c->bulk_read = 0;
945 			break;
946 		case Opt_chk_data_crc:
947 			c->mount_opts.chk_data_crc = 2;
948 			c->no_chk_data_crc = 0;
949 			break;
950 		case Opt_no_chk_data_crc:
951 			c->mount_opts.chk_data_crc = 1;
952 			c->no_chk_data_crc = 1;
953 			break;
954 		default:
955 			ubifs_err("unrecognized mount option \"%s\" "
956 				  "or missing value", p);
957 			return -EINVAL;
958 		}
959 	}
960 
961 	return 0;
962 }
963 
964 /**
965  * destroy_journal - destroy journal data structures.
966  * @c: UBIFS file-system description object
967  *
968  * This function destroys journal data structures including those that may have
969  * been created by recovery functions.
970  */
971 static void destroy_journal(struct ubifs_info *c)
972 {
973 	while (!list_empty(&c->unclean_leb_list)) {
974 		struct ubifs_unclean_leb *ucleb;
975 
976 		ucleb = list_entry(c->unclean_leb_list.next,
977 				   struct ubifs_unclean_leb, list);
978 		list_del(&ucleb->list);
979 		kfree(ucleb);
980 	}
981 	while (!list_empty(&c->old_buds)) {
982 		struct ubifs_bud *bud;
983 
984 		bud = list_entry(c->old_buds.next, struct ubifs_bud, list);
985 		list_del(&bud->list);
986 		kfree(bud);
987 	}
988 	ubifs_destroy_idx_gc(c);
989 	ubifs_destroy_size_tree(c);
990 	ubifs_tnc_close(c);
991 	free_buds(c);
992 }
993 
994 /**
995  * mount_ubifs - mount UBIFS file-system.
996  * @c: UBIFS file-system description object
997  *
998  * This function mounts UBIFS file system. Returns zero in case of success and
999  * a negative error code in case of failure.
1000  *
1001  * Note, the function does not de-allocate resources it it fails half way
1002  * through, and the caller has to do this instead.
1003  */
1004 static int mount_ubifs(struct ubifs_info *c)
1005 {
1006 	struct super_block *sb = c->vfs_sb;
1007 	int err, mounted_read_only = (sb->s_flags & MS_RDONLY);
1008 	long long x;
1009 	size_t sz;
1010 
1011 	err = init_constants_early(c);
1012 	if (err)
1013 		return err;
1014 
1015 #ifdef CONFIG_UBIFS_FS_DEBUG
1016 	c->dbg_buf = vmalloc(c->leb_size);
1017 	if (!c->dbg_buf)
1018 		return -ENOMEM;
1019 #endif
1020 
1021 	err = check_volume_empty(c);
1022 	if (err)
1023 		goto out_free;
1024 
1025 	if (c->empty && (mounted_read_only || c->ro_media)) {
1026 		/*
1027 		 * This UBI volume is empty, and read-only, or the file system
1028 		 * is mounted read-only - we cannot format it.
1029 		 */
1030 		ubifs_err("can't format empty UBI volume: read-only %s",
1031 			  c->ro_media ? "UBI volume" : "mount");
1032 		err = -EROFS;
1033 		goto out_free;
1034 	}
1035 
1036 	if (c->ro_media && !mounted_read_only) {
1037 		ubifs_err("cannot mount read-write - read-only media");
1038 		err = -EROFS;
1039 		goto out_free;
1040 	}
1041 
1042 	/*
1043 	 * The requirement for the buffer is that it should fit indexing B-tree
1044 	 * height amount of integers. We assume the height if the TNC tree will
1045 	 * never exceed 64.
1046 	 */
1047 	err = -ENOMEM;
1048 	c->bottom_up_buf = kmalloc(BOTTOM_UP_HEIGHT * sizeof(int), GFP_KERNEL);
1049 	if (!c->bottom_up_buf)
1050 		goto out_free;
1051 
1052 	c->sbuf = vmalloc(c->leb_size);
1053 	if (!c->sbuf)
1054 		goto out_free;
1055 
1056 	if (!mounted_read_only) {
1057 		c->ileb_buf = vmalloc(c->leb_size);
1058 		if (!c->ileb_buf)
1059 			goto out_free;
1060 	}
1061 
1062 	c->always_chk_crc = 1;
1063 
1064 	err = ubifs_read_superblock(c);
1065 	if (err)
1066 		goto out_free;
1067 
1068 	/*
1069 	 * Make sure the compressor which is set as the default on in the
1070 	 * superblock was actually compiled in.
1071 	 */
1072 	if (!ubifs_compr_present(c->default_compr)) {
1073 		ubifs_warn("'%s' compressor is set by superblock, but not "
1074 			   "compiled in", ubifs_compr_name(c->default_compr));
1075 		c->default_compr = UBIFS_COMPR_NONE;
1076 	}
1077 
1078 	dbg_failure_mode_registration(c);
1079 
1080 	err = init_constants_late(c);
1081 	if (err)
1082 		goto out_dereg;
1083 
1084 	sz = ALIGN(c->max_idx_node_sz, c->min_io_size);
1085 	sz = ALIGN(sz + c->max_idx_node_sz, c->min_io_size);
1086 	c->cbuf = kmalloc(sz, GFP_NOFS);
1087 	if (!c->cbuf) {
1088 		err = -ENOMEM;
1089 		goto out_dereg;
1090 	}
1091 
1092 	sprintf(c->bgt_name, BGT_NAME_PATTERN, c->vi.ubi_num, c->vi.vol_id);
1093 	if (!mounted_read_only) {
1094 		err = alloc_wbufs(c);
1095 		if (err)
1096 			goto out_cbuf;
1097 
1098 		/* Create background thread */
1099 		c->bgt = kthread_create(ubifs_bg_thread, c, c->bgt_name);
1100 		if (IS_ERR(c->bgt)) {
1101 			err = PTR_ERR(c->bgt);
1102 			c->bgt = NULL;
1103 			ubifs_err("cannot spawn \"%s\", error %d",
1104 				  c->bgt_name, err);
1105 			goto out_wbufs;
1106 		}
1107 		wake_up_process(c->bgt);
1108 	}
1109 
1110 	err = ubifs_read_master(c);
1111 	if (err)
1112 		goto out_master;
1113 
1114 	if ((c->mst_node->flags & cpu_to_le32(UBIFS_MST_DIRTY)) != 0) {
1115 		ubifs_msg("recovery needed");
1116 		c->need_recovery = 1;
1117 		if (!mounted_read_only) {
1118 			err = ubifs_recover_inl_heads(c, c->sbuf);
1119 			if (err)
1120 				goto out_master;
1121 		}
1122 	} else if (!mounted_read_only) {
1123 		/*
1124 		 * Set the "dirty" flag so that if we reboot uncleanly we
1125 		 * will notice this immediately on the next mount.
1126 		 */
1127 		c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
1128 		err = ubifs_write_master(c);
1129 		if (err)
1130 			goto out_master;
1131 	}
1132 
1133 	err = ubifs_lpt_init(c, 1, !mounted_read_only);
1134 	if (err)
1135 		goto out_lpt;
1136 
1137 	err = dbg_check_idx_size(c, c->old_idx_sz);
1138 	if (err)
1139 		goto out_lpt;
1140 
1141 	err = ubifs_replay_journal(c);
1142 	if (err)
1143 		goto out_journal;
1144 
1145 	err = ubifs_mount_orphans(c, c->need_recovery, mounted_read_only);
1146 	if (err)
1147 		goto out_orphans;
1148 
1149 	if (!mounted_read_only) {
1150 		int lnum;
1151 
1152 		/* Check for enough free space */
1153 		if (ubifs_calc_available(c, c->min_idx_lebs) <= 0) {
1154 			ubifs_err("insufficient available space");
1155 			err = -EINVAL;
1156 			goto out_orphans;
1157 		}
1158 
1159 		/* Check for enough log space */
1160 		lnum = c->lhead_lnum + 1;
1161 		if (lnum >= UBIFS_LOG_LNUM + c->log_lebs)
1162 			lnum = UBIFS_LOG_LNUM;
1163 		if (lnum == c->ltail_lnum) {
1164 			err = ubifs_consolidate_log(c);
1165 			if (err)
1166 				goto out_orphans;
1167 		}
1168 
1169 		if (c->need_recovery) {
1170 			err = ubifs_recover_size(c);
1171 			if (err)
1172 				goto out_orphans;
1173 			err = ubifs_rcvry_gc_commit(c);
1174 		} else
1175 			err = take_gc_lnum(c);
1176 		if (err)
1177 			goto out_orphans;
1178 
1179 		err = dbg_check_lprops(c);
1180 		if (err)
1181 			goto out_orphans;
1182 	} else if (c->need_recovery) {
1183 		err = ubifs_recover_size(c);
1184 		if (err)
1185 			goto out_orphans;
1186 	}
1187 
1188 	spin_lock(&ubifs_infos_lock);
1189 	list_add_tail(&c->infos_list, &ubifs_infos);
1190 	spin_unlock(&ubifs_infos_lock);
1191 
1192 	if (c->need_recovery) {
1193 		if (mounted_read_only)
1194 			ubifs_msg("recovery deferred");
1195 		else {
1196 			c->need_recovery = 0;
1197 			ubifs_msg("recovery completed");
1198 		}
1199 	}
1200 
1201 	err = dbg_check_filesystem(c);
1202 	if (err)
1203 		goto out_infos;
1204 
1205 	c->always_chk_crc = 0;
1206 
1207 	ubifs_msg("mounted UBI device %d, volume %d, name \"%s\"",
1208 		  c->vi.ubi_num, c->vi.vol_id, c->vi.name);
1209 	if (mounted_read_only)
1210 		ubifs_msg("mounted read-only");
1211 	x = (long long)c->main_lebs * c->leb_size;
1212 	ubifs_msg("file system size:   %lld bytes (%lld KiB, %lld MiB, %d "
1213 		  "LEBs)", x, x >> 10, x >> 20, c->main_lebs);
1214 	x = (long long)c->log_lebs * c->leb_size + c->max_bud_bytes;
1215 	ubifs_msg("journal size:       %lld bytes (%lld KiB, %lld MiB, %d "
1216 		  "LEBs)", x, x >> 10, x >> 20, c->log_lebs + c->max_bud_cnt);
1217 	ubifs_msg("media format:       %d (latest is %d)",
1218 		  c->fmt_version, UBIFS_FORMAT_VERSION);
1219 	ubifs_msg("default compressor: %s", ubifs_compr_name(c->default_compr));
1220 	ubifs_msg("reserved for root:  %llu bytes (%llu KiB)",
1221 		c->report_rp_size, c->report_rp_size >> 10);
1222 
1223 	dbg_msg("compiled on:         " __DATE__ " at " __TIME__);
1224 	dbg_msg("min. I/O unit size:  %d bytes", c->min_io_size);
1225 	dbg_msg("LEB size:            %d bytes (%d KiB)",
1226 		c->leb_size, c->leb_size >> 10);
1227 	dbg_msg("data journal heads:  %d",
1228 		c->jhead_cnt - NONDATA_JHEADS_CNT);
1229 	dbg_msg("UUID:                %02X%02X%02X%02X-%02X%02X"
1230 	       "-%02X%02X-%02X%02X-%02X%02X%02X%02X%02X%02X",
1231 	       c->uuid[0], c->uuid[1], c->uuid[2], c->uuid[3],
1232 	       c->uuid[4], c->uuid[5], c->uuid[6], c->uuid[7],
1233 	       c->uuid[8], c->uuid[9], c->uuid[10], c->uuid[11],
1234 	       c->uuid[12], c->uuid[13], c->uuid[14], c->uuid[15]);
1235 	dbg_msg("fast unmount:        %d", c->fast_unmount);
1236 	dbg_msg("big_lpt              %d", c->big_lpt);
1237 	dbg_msg("log LEBs:            %d (%d - %d)",
1238 		c->log_lebs, UBIFS_LOG_LNUM, c->log_last);
1239 	dbg_msg("LPT area LEBs:       %d (%d - %d)",
1240 		c->lpt_lebs, c->lpt_first, c->lpt_last);
1241 	dbg_msg("orphan area LEBs:    %d (%d - %d)",
1242 		c->orph_lebs, c->orph_first, c->orph_last);
1243 	dbg_msg("main area LEBs:      %d (%d - %d)",
1244 		c->main_lebs, c->main_first, c->leb_cnt - 1);
1245 	dbg_msg("index LEBs:          %d", c->lst.idx_lebs);
1246 	dbg_msg("total index bytes:   %lld (%lld KiB, %lld MiB)",
1247 		c->old_idx_sz, c->old_idx_sz >> 10, c->old_idx_sz >> 20);
1248 	dbg_msg("key hash type:       %d", c->key_hash_type);
1249 	dbg_msg("tree fanout:         %d", c->fanout);
1250 	dbg_msg("reserved GC LEB:     %d", c->gc_lnum);
1251 	dbg_msg("first main LEB:      %d", c->main_first);
1252 	dbg_msg("dead watermark:      %d", c->dead_wm);
1253 	dbg_msg("dark watermark:      %d", c->dark_wm);
1254 	x = (long long)c->main_lebs * c->dark_wm;
1255 	dbg_msg("max. dark space:     %lld (%lld KiB, %lld MiB)",
1256 		x, x >> 10, x >> 20);
1257 	dbg_msg("maximum bud bytes:   %lld (%lld KiB, %lld MiB)",
1258 		c->max_bud_bytes, c->max_bud_bytes >> 10,
1259 		c->max_bud_bytes >> 20);
1260 	dbg_msg("BG commit bud bytes: %lld (%lld KiB, %lld MiB)",
1261 		c->bg_bud_bytes, c->bg_bud_bytes >> 10,
1262 		c->bg_bud_bytes >> 20);
1263 	dbg_msg("current bud bytes    %lld (%lld KiB, %lld MiB)",
1264 		c->bud_bytes, c->bud_bytes >> 10, c->bud_bytes >> 20);
1265 	dbg_msg("max. seq. number:    %llu", c->max_sqnum);
1266 	dbg_msg("commit number:       %llu", c->cmt_no);
1267 
1268 	return 0;
1269 
1270 out_infos:
1271 	spin_lock(&ubifs_infos_lock);
1272 	list_del(&c->infos_list);
1273 	spin_unlock(&ubifs_infos_lock);
1274 out_orphans:
1275 	free_orphans(c);
1276 out_journal:
1277 	destroy_journal(c);
1278 out_lpt:
1279 	ubifs_lpt_free(c, 0);
1280 out_master:
1281 	kfree(c->mst_node);
1282 	kfree(c->rcvrd_mst_node);
1283 	if (c->bgt)
1284 		kthread_stop(c->bgt);
1285 out_wbufs:
1286 	free_wbufs(c);
1287 out_cbuf:
1288 	kfree(c->cbuf);
1289 out_dereg:
1290 	dbg_failure_mode_deregistration(c);
1291 out_free:
1292 	vfree(c->ileb_buf);
1293 	vfree(c->sbuf);
1294 	kfree(c->bottom_up_buf);
1295 	UBIFS_DBG(vfree(c->dbg_buf));
1296 	return err;
1297 }
1298 
1299 /**
1300  * ubifs_umount - un-mount UBIFS file-system.
1301  * @c: UBIFS file-system description object
1302  *
1303  * Note, this function is called to free allocated resourced when un-mounting,
1304  * as well as free resources when an error occurred while we were half way
1305  * through mounting (error path cleanup function). So it has to make sure the
1306  * resource was actually allocated before freeing it.
1307  */
1308 static void ubifs_umount(struct ubifs_info *c)
1309 {
1310 	dbg_gen("un-mounting UBI device %d, volume %d", c->vi.ubi_num,
1311 		c->vi.vol_id);
1312 
1313 	spin_lock(&ubifs_infos_lock);
1314 	list_del(&c->infos_list);
1315 	spin_unlock(&ubifs_infos_lock);
1316 
1317 	if (c->bgt)
1318 		kthread_stop(c->bgt);
1319 
1320 	destroy_journal(c);
1321 	free_wbufs(c);
1322 	free_orphans(c);
1323 	ubifs_lpt_free(c, 0);
1324 
1325 	kfree(c->cbuf);
1326 	kfree(c->rcvrd_mst_node);
1327 	kfree(c->mst_node);
1328 	vfree(c->sbuf);
1329 	kfree(c->bottom_up_buf);
1330 	UBIFS_DBG(vfree(c->dbg_buf));
1331 	vfree(c->ileb_buf);
1332 	dbg_failure_mode_deregistration(c);
1333 }
1334 
1335 /**
1336  * ubifs_remount_rw - re-mount in read-write mode.
1337  * @c: UBIFS file-system description object
1338  *
1339  * UBIFS avoids allocating many unnecessary resources when mounted in read-only
1340  * mode. This function allocates the needed resources and re-mounts UBIFS in
1341  * read-write mode.
1342  */
1343 static int ubifs_remount_rw(struct ubifs_info *c)
1344 {
1345 	int err, lnum;
1346 
1347 	if (c->ro_media)
1348 		return -EINVAL;
1349 
1350 	mutex_lock(&c->umount_mutex);
1351 	c->remounting_rw = 1;
1352 	c->always_chk_crc = 1;
1353 
1354 	/* Check for enough free space */
1355 	if (ubifs_calc_available(c, c->min_idx_lebs) <= 0) {
1356 		ubifs_err("insufficient available space");
1357 		err = -EINVAL;
1358 		goto out;
1359 	}
1360 
1361 	if (c->old_leb_cnt != c->leb_cnt) {
1362 		struct ubifs_sb_node *sup;
1363 
1364 		sup = ubifs_read_sb_node(c);
1365 		if (IS_ERR(sup)) {
1366 			err = PTR_ERR(sup);
1367 			goto out;
1368 		}
1369 		sup->leb_cnt = cpu_to_le32(c->leb_cnt);
1370 		err = ubifs_write_sb_node(c, sup);
1371 		if (err)
1372 			goto out;
1373 	}
1374 
1375 	if (c->need_recovery) {
1376 		ubifs_msg("completing deferred recovery");
1377 		err = ubifs_write_rcvrd_mst_node(c);
1378 		if (err)
1379 			goto out;
1380 		err = ubifs_recover_size(c);
1381 		if (err)
1382 			goto out;
1383 		err = ubifs_clean_lebs(c, c->sbuf);
1384 		if (err)
1385 			goto out;
1386 		err = ubifs_recover_inl_heads(c, c->sbuf);
1387 		if (err)
1388 			goto out;
1389 	}
1390 
1391 	if (!(c->mst_node->flags & cpu_to_le32(UBIFS_MST_DIRTY))) {
1392 		c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
1393 		err = ubifs_write_master(c);
1394 		if (err)
1395 			goto out;
1396 	}
1397 
1398 	c->ileb_buf = vmalloc(c->leb_size);
1399 	if (!c->ileb_buf) {
1400 		err = -ENOMEM;
1401 		goto out;
1402 	}
1403 
1404 	err = ubifs_lpt_init(c, 0, 1);
1405 	if (err)
1406 		goto out;
1407 
1408 	err = alloc_wbufs(c);
1409 	if (err)
1410 		goto out;
1411 
1412 	ubifs_create_buds_lists(c);
1413 
1414 	/* Create background thread */
1415 	c->bgt = kthread_create(ubifs_bg_thread, c, c->bgt_name);
1416 	if (IS_ERR(c->bgt)) {
1417 		err = PTR_ERR(c->bgt);
1418 		c->bgt = NULL;
1419 		ubifs_err("cannot spawn \"%s\", error %d",
1420 			  c->bgt_name, err);
1421 		goto out;
1422 	}
1423 	wake_up_process(c->bgt);
1424 
1425 	c->orph_buf = vmalloc(c->leb_size);
1426 	if (!c->orph_buf) {
1427 		err = -ENOMEM;
1428 		goto out;
1429 	}
1430 
1431 	/* Check for enough log space */
1432 	lnum = c->lhead_lnum + 1;
1433 	if (lnum >= UBIFS_LOG_LNUM + c->log_lebs)
1434 		lnum = UBIFS_LOG_LNUM;
1435 	if (lnum == c->ltail_lnum) {
1436 		err = ubifs_consolidate_log(c);
1437 		if (err)
1438 			goto out;
1439 	}
1440 
1441 	if (c->need_recovery)
1442 		err = ubifs_rcvry_gc_commit(c);
1443 	else
1444 		err = take_gc_lnum(c);
1445 	if (err)
1446 		goto out;
1447 
1448 	if (c->need_recovery) {
1449 		c->need_recovery = 0;
1450 		ubifs_msg("deferred recovery completed");
1451 	}
1452 
1453 	dbg_gen("re-mounted read-write");
1454 	c->vfs_sb->s_flags &= ~MS_RDONLY;
1455 	c->remounting_rw = 0;
1456 	c->always_chk_crc = 0;
1457 	mutex_unlock(&c->umount_mutex);
1458 	return 0;
1459 
1460 out:
1461 	vfree(c->orph_buf);
1462 	c->orph_buf = NULL;
1463 	if (c->bgt) {
1464 		kthread_stop(c->bgt);
1465 		c->bgt = NULL;
1466 	}
1467 	free_wbufs(c);
1468 	vfree(c->ileb_buf);
1469 	c->ileb_buf = NULL;
1470 	ubifs_lpt_free(c, 1);
1471 	c->remounting_rw = 0;
1472 	c->always_chk_crc = 0;
1473 	mutex_unlock(&c->umount_mutex);
1474 	return err;
1475 }
1476 
1477 /**
1478  * commit_on_unmount - commit the journal when un-mounting.
1479  * @c: UBIFS file-system description object
1480  *
1481  * This function is called during un-mounting and re-mounting, and it commits
1482  * the journal unless the "fast unmount" mode is enabled. It also avoids
1483  * committing the journal if it contains too few data.
1484  */
1485 static void commit_on_unmount(struct ubifs_info *c)
1486 {
1487 	if (!c->fast_unmount) {
1488 		long long bud_bytes;
1489 
1490 		spin_lock(&c->buds_lock);
1491 		bud_bytes = c->bud_bytes;
1492 		spin_unlock(&c->buds_lock);
1493 		if (bud_bytes > c->leb_size)
1494 			ubifs_run_commit(c);
1495 	}
1496 }
1497 
1498 /**
1499  * ubifs_remount_ro - re-mount in read-only mode.
1500  * @c: UBIFS file-system description object
1501  *
1502  * We rely on VFS to have stopped writing. Possibly the background thread could
1503  * be running a commit, however kthread_stop will wait in that case.
1504  */
1505 static void ubifs_remount_ro(struct ubifs_info *c)
1506 {
1507 	int i, err;
1508 
1509 	ubifs_assert(!c->need_recovery);
1510 	commit_on_unmount(c);
1511 
1512 	mutex_lock(&c->umount_mutex);
1513 	if (c->bgt) {
1514 		kthread_stop(c->bgt);
1515 		c->bgt = NULL;
1516 	}
1517 
1518 	for (i = 0; i < c->jhead_cnt; i++) {
1519 		ubifs_wbuf_sync(&c->jheads[i].wbuf);
1520 		del_timer_sync(&c->jheads[i].wbuf.timer);
1521 	}
1522 
1523 	if (!c->ro_media) {
1524 		c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_DIRTY);
1525 		c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
1526 		c->mst_node->gc_lnum = cpu_to_le32(c->gc_lnum);
1527 		err = ubifs_write_master(c);
1528 		if (err)
1529 			ubifs_ro_mode(c, err);
1530 	}
1531 
1532 	ubifs_destroy_idx_gc(c);
1533 	free_wbufs(c);
1534 	vfree(c->orph_buf);
1535 	c->orph_buf = NULL;
1536 	vfree(c->ileb_buf);
1537 	c->ileb_buf = NULL;
1538 	ubifs_lpt_free(c, 1);
1539 	mutex_unlock(&c->umount_mutex);
1540 }
1541 
1542 static void ubifs_put_super(struct super_block *sb)
1543 {
1544 	int i;
1545 	struct ubifs_info *c = sb->s_fs_info;
1546 
1547 	ubifs_msg("un-mount UBI device %d, volume %d", c->vi.ubi_num,
1548 		  c->vi.vol_id);
1549 	/*
1550 	 * The following asserts are only valid if there has not been a failure
1551 	 * of the media. For example, there will be dirty inodes if we failed
1552 	 * to write them back because of I/O errors.
1553 	 */
1554 	ubifs_assert(atomic_long_read(&c->dirty_pg_cnt) == 0);
1555 	ubifs_assert(c->budg_idx_growth == 0);
1556 	ubifs_assert(c->budg_dd_growth == 0);
1557 	ubifs_assert(c->budg_data_growth == 0);
1558 
1559 	/*
1560 	 * The 'c->umount_lock' prevents races between UBIFS memory shrinker
1561 	 * and file system un-mount. Namely, it prevents the shrinker from
1562 	 * picking this superblock for shrinking - it will be just skipped if
1563 	 * the mutex is locked.
1564 	 */
1565 	mutex_lock(&c->umount_mutex);
1566 	if (!(c->vfs_sb->s_flags & MS_RDONLY)) {
1567 		/*
1568 		 * First of all kill the background thread to make sure it does
1569 		 * not interfere with un-mounting and freeing resources.
1570 		 */
1571 		if (c->bgt) {
1572 			kthread_stop(c->bgt);
1573 			c->bgt = NULL;
1574 		}
1575 
1576 		/* Synchronize write-buffers */
1577 		if (c->jheads)
1578 			for (i = 0; i < c->jhead_cnt; i++) {
1579 				ubifs_wbuf_sync(&c->jheads[i].wbuf);
1580 				del_timer_sync(&c->jheads[i].wbuf.timer);
1581 			}
1582 
1583 		/*
1584 		 * On fatal errors c->ro_media is set to 1, in which case we do
1585 		 * not write the master node.
1586 		 */
1587 		if (!c->ro_media) {
1588 			/*
1589 			 * We are being cleanly unmounted which means the
1590 			 * orphans were killed - indicate this in the master
1591 			 * node. Also save the reserved GC LEB number.
1592 			 */
1593 			int err;
1594 
1595 			c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_DIRTY);
1596 			c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
1597 			c->mst_node->gc_lnum = cpu_to_le32(c->gc_lnum);
1598 			err = ubifs_write_master(c);
1599 			if (err)
1600 				/*
1601 				 * Recovery will attempt to fix the master area
1602 				 * next mount, so we just print a message and
1603 				 * continue to unmount normally.
1604 				 */
1605 				ubifs_err("failed to write master node, "
1606 					  "error %d", err);
1607 		}
1608 	}
1609 
1610 	ubifs_umount(c);
1611 	bdi_destroy(&c->bdi);
1612 	ubi_close_volume(c->ubi);
1613 	mutex_unlock(&c->umount_mutex);
1614 	kfree(c);
1615 }
1616 
1617 static int ubifs_remount_fs(struct super_block *sb, int *flags, char *data)
1618 {
1619 	int err;
1620 	struct ubifs_info *c = sb->s_fs_info;
1621 
1622 	dbg_gen("old flags %#lx, new flags %#x", sb->s_flags, *flags);
1623 
1624 	err = ubifs_parse_options(c, data, 1);
1625 	if (err) {
1626 		ubifs_err("invalid or unknown remount parameter");
1627 		return err;
1628 	}
1629 	if ((sb->s_flags & MS_RDONLY) && !(*flags & MS_RDONLY)) {
1630 		err = ubifs_remount_rw(c);
1631 		if (err)
1632 			return err;
1633 	} else if (!(sb->s_flags & MS_RDONLY) && (*flags & MS_RDONLY))
1634 		ubifs_remount_ro(c);
1635 
1636 	return 0;
1637 }
1638 
1639 struct super_operations ubifs_super_operations = {
1640 	.alloc_inode   = ubifs_alloc_inode,
1641 	.destroy_inode = ubifs_destroy_inode,
1642 	.put_super     = ubifs_put_super,
1643 	.write_inode   = ubifs_write_inode,
1644 	.delete_inode  = ubifs_delete_inode,
1645 	.statfs        = ubifs_statfs,
1646 	.dirty_inode   = ubifs_dirty_inode,
1647 	.remount_fs    = ubifs_remount_fs,
1648 	.show_options  = ubifs_show_options,
1649 	.sync_fs       = ubifs_sync_fs,
1650 };
1651 
1652 /**
1653  * open_ubi - parse UBI device name string and open the UBI device.
1654  * @name: UBI volume name
1655  * @mode: UBI volume open mode
1656  *
1657  * There are several ways to specify UBI volumes when mounting UBIFS:
1658  * o ubiX_Y    - UBI device number X, volume Y;
1659  * o ubiY      - UBI device number 0, volume Y;
1660  * o ubiX:NAME - mount UBI device X, volume with name NAME;
1661  * o ubi:NAME  - mount UBI device 0, volume with name NAME.
1662  *
1663  * Alternative '!' separator may be used instead of ':' (because some shells
1664  * like busybox may interpret ':' as an NFS host name separator). This function
1665  * returns ubi volume object in case of success and a negative error code in
1666  * case of failure.
1667  */
1668 static struct ubi_volume_desc *open_ubi(const char *name, int mode)
1669 {
1670 	int dev, vol;
1671 	char *endptr;
1672 
1673 	if (name[0] != 'u' || name[1] != 'b' || name[2] != 'i')
1674 		return ERR_PTR(-EINVAL);
1675 
1676 	/* ubi:NAME method */
1677 	if ((name[3] == ':' || name[3] == '!') && name[4] != '\0')
1678 		return ubi_open_volume_nm(0, name + 4, mode);
1679 
1680 	if (!isdigit(name[3]))
1681 		return ERR_PTR(-EINVAL);
1682 
1683 	dev = simple_strtoul(name + 3, &endptr, 0);
1684 
1685 	/* ubiY method */
1686 	if (*endptr == '\0')
1687 		return ubi_open_volume(0, dev, mode);
1688 
1689 	/* ubiX_Y method */
1690 	if (*endptr == '_' && isdigit(endptr[1])) {
1691 		vol = simple_strtoul(endptr + 1, &endptr, 0);
1692 		if (*endptr != '\0')
1693 			return ERR_PTR(-EINVAL);
1694 		return ubi_open_volume(dev, vol, mode);
1695 	}
1696 
1697 	/* ubiX:NAME method */
1698 	if ((*endptr == ':' || *endptr == '!') && endptr[1] != '\0')
1699 		return ubi_open_volume_nm(dev, ++endptr, mode);
1700 
1701 	return ERR_PTR(-EINVAL);
1702 }
1703 
1704 static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
1705 {
1706 	struct ubi_volume_desc *ubi = sb->s_fs_info;
1707 	struct ubifs_info *c;
1708 	struct inode *root;
1709 	int err;
1710 
1711 	c = kzalloc(sizeof(struct ubifs_info), GFP_KERNEL);
1712 	if (!c)
1713 		return -ENOMEM;
1714 
1715 	spin_lock_init(&c->cnt_lock);
1716 	spin_lock_init(&c->cs_lock);
1717 	spin_lock_init(&c->buds_lock);
1718 	spin_lock_init(&c->space_lock);
1719 	spin_lock_init(&c->orphan_lock);
1720 	init_rwsem(&c->commit_sem);
1721 	mutex_init(&c->lp_mutex);
1722 	mutex_init(&c->tnc_mutex);
1723 	mutex_init(&c->log_mutex);
1724 	mutex_init(&c->mst_mutex);
1725 	mutex_init(&c->umount_mutex);
1726 	init_waitqueue_head(&c->cmt_wq);
1727 	c->buds = RB_ROOT;
1728 	c->old_idx = RB_ROOT;
1729 	c->size_tree = RB_ROOT;
1730 	c->orph_tree = RB_ROOT;
1731 	INIT_LIST_HEAD(&c->infos_list);
1732 	INIT_LIST_HEAD(&c->idx_gc);
1733 	INIT_LIST_HEAD(&c->replay_list);
1734 	INIT_LIST_HEAD(&c->replay_buds);
1735 	INIT_LIST_HEAD(&c->uncat_list);
1736 	INIT_LIST_HEAD(&c->empty_list);
1737 	INIT_LIST_HEAD(&c->freeable_list);
1738 	INIT_LIST_HEAD(&c->frdi_idx_list);
1739 	INIT_LIST_HEAD(&c->unclean_leb_list);
1740 	INIT_LIST_HEAD(&c->old_buds);
1741 	INIT_LIST_HEAD(&c->orph_list);
1742 	INIT_LIST_HEAD(&c->orph_new);
1743 
1744 	c->highest_inum = UBIFS_FIRST_INO;
1745 	c->lhead_lnum = c->ltail_lnum = UBIFS_LOG_LNUM;
1746 
1747 	ubi_get_volume_info(ubi, &c->vi);
1748 	ubi_get_device_info(c->vi.ubi_num, &c->di);
1749 
1750 	/* Re-open the UBI device in read-write mode */
1751 	c->ubi = ubi_open_volume(c->vi.ubi_num, c->vi.vol_id, UBI_READWRITE);
1752 	if (IS_ERR(c->ubi)) {
1753 		err = PTR_ERR(c->ubi);
1754 		goto out_free;
1755 	}
1756 
1757 	/*
1758 	 * UBIFS provides 'backing_dev_info' in order to disable read-ahead. For
1759 	 * UBIFS, I/O is not deferred, it is done immediately in readpage,
1760 	 * which means the user would have to wait not just for their own I/O
1761 	 * but the read-ahead I/O as well i.e. completely pointless.
1762 	 *
1763 	 * Read-ahead will be disabled because @c->bdi.ra_pages is 0.
1764 	 */
1765 	c->bdi.capabilities = BDI_CAP_MAP_COPY;
1766 	c->bdi.unplug_io_fn = default_unplug_io_fn;
1767 	err  = bdi_init(&c->bdi);
1768 	if (err)
1769 		goto out_close;
1770 
1771 	err = ubifs_parse_options(c, data, 0);
1772 	if (err)
1773 		goto out_bdi;
1774 
1775 	c->vfs_sb = sb;
1776 
1777 	sb->s_fs_info = c;
1778 	sb->s_magic = UBIFS_SUPER_MAGIC;
1779 	sb->s_blocksize = UBIFS_BLOCK_SIZE;
1780 	sb->s_blocksize_bits = UBIFS_BLOCK_SHIFT;
1781 	sb->s_dev = c->vi.cdev;
1782 	sb->s_maxbytes = c->max_inode_sz = key_max_inode_size(c);
1783 	if (c->max_inode_sz > MAX_LFS_FILESIZE)
1784 		sb->s_maxbytes = c->max_inode_sz = MAX_LFS_FILESIZE;
1785 	sb->s_op = &ubifs_super_operations;
1786 
1787 	mutex_lock(&c->umount_mutex);
1788 	err = mount_ubifs(c);
1789 	if (err) {
1790 		ubifs_assert(err < 0);
1791 		goto out_unlock;
1792 	}
1793 
1794 	/* Read the root inode */
1795 	root = ubifs_iget(sb, UBIFS_ROOT_INO);
1796 	if (IS_ERR(root)) {
1797 		err = PTR_ERR(root);
1798 		goto out_umount;
1799 	}
1800 
1801 	sb->s_root = d_alloc_root(root);
1802 	if (!sb->s_root)
1803 		goto out_iput;
1804 
1805 	mutex_unlock(&c->umount_mutex);
1806 
1807 	return 0;
1808 
1809 out_iput:
1810 	iput(root);
1811 out_umount:
1812 	ubifs_umount(c);
1813 out_unlock:
1814 	mutex_unlock(&c->umount_mutex);
1815 out_bdi:
1816 	bdi_destroy(&c->bdi);
1817 out_close:
1818 	ubi_close_volume(c->ubi);
1819 out_free:
1820 	kfree(c);
1821 	return err;
1822 }
1823 
1824 static int sb_test(struct super_block *sb, void *data)
1825 {
1826 	dev_t *dev = data;
1827 
1828 	return sb->s_dev == *dev;
1829 }
1830 
1831 static int sb_set(struct super_block *sb, void *data)
1832 {
1833 	dev_t *dev = data;
1834 
1835 	sb->s_dev = *dev;
1836 	return 0;
1837 }
1838 
1839 static int ubifs_get_sb(struct file_system_type *fs_type, int flags,
1840 			const char *name, void *data, struct vfsmount *mnt)
1841 {
1842 	struct ubi_volume_desc *ubi;
1843 	struct ubi_volume_info vi;
1844 	struct super_block *sb;
1845 	int err;
1846 
1847 	dbg_gen("name %s, flags %#x", name, flags);
1848 
1849 	/*
1850 	 * Get UBI device number and volume ID. Mount it read-only so far
1851 	 * because this might be a new mount point, and UBI allows only one
1852 	 * read-write user at a time.
1853 	 */
1854 	ubi = open_ubi(name, UBI_READONLY);
1855 	if (IS_ERR(ubi)) {
1856 		ubifs_err("cannot open \"%s\", error %d",
1857 			  name, (int)PTR_ERR(ubi));
1858 		return PTR_ERR(ubi);
1859 	}
1860 	ubi_get_volume_info(ubi, &vi);
1861 
1862 	dbg_gen("opened ubi%d_%d", vi.ubi_num, vi.vol_id);
1863 
1864 	sb = sget(fs_type, &sb_test, &sb_set, &vi.cdev);
1865 	if (IS_ERR(sb)) {
1866 		err = PTR_ERR(sb);
1867 		goto out_close;
1868 	}
1869 
1870 	if (sb->s_root) {
1871 		/* A new mount point for already mounted UBIFS */
1872 		dbg_gen("this ubi volume is already mounted");
1873 		if ((flags ^ sb->s_flags) & MS_RDONLY) {
1874 			err = -EBUSY;
1875 			goto out_deact;
1876 		}
1877 	} else {
1878 		sb->s_flags = flags;
1879 		/*
1880 		 * Pass 'ubi' to 'fill_super()' in sb->s_fs_info where it is
1881 		 * replaced by 'c'.
1882 		 */
1883 		sb->s_fs_info = ubi;
1884 		err = ubifs_fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
1885 		if (err)
1886 			goto out_deact;
1887 		/* We do not support atime */
1888 		sb->s_flags |= MS_ACTIVE | MS_NOATIME;
1889 	}
1890 
1891 	/* 'fill_super()' opens ubi again so we must close it here */
1892 	ubi_close_volume(ubi);
1893 
1894 	return simple_set_mnt(mnt, sb);
1895 
1896 out_deact:
1897 	up_write(&sb->s_umount);
1898 	deactivate_super(sb);
1899 out_close:
1900 	ubi_close_volume(ubi);
1901 	return err;
1902 }
1903 
1904 static void ubifs_kill_sb(struct super_block *sb)
1905 {
1906 	struct ubifs_info *c = sb->s_fs_info;
1907 
1908 	/*
1909 	 * We do 'commit_on_unmount()' here instead of 'ubifs_put_super()'
1910 	 * in order to be outside BKL.
1911 	 */
1912 	if (sb->s_root && !(sb->s_flags & MS_RDONLY))
1913 		commit_on_unmount(c);
1914 	/* The un-mount routine is actually done in put_super() */
1915 	generic_shutdown_super(sb);
1916 }
1917 
1918 static struct file_system_type ubifs_fs_type = {
1919 	.name    = "ubifs",
1920 	.owner   = THIS_MODULE,
1921 	.get_sb  = ubifs_get_sb,
1922 	.kill_sb = ubifs_kill_sb
1923 };
1924 
1925 /*
1926  * Inode slab cache constructor.
1927  */
1928 static void inode_slab_ctor(void *obj)
1929 {
1930 	struct ubifs_inode *ui = obj;
1931 	inode_init_once(&ui->vfs_inode);
1932 }
1933 
1934 static int __init ubifs_init(void)
1935 {
1936 	int err;
1937 
1938 	BUILD_BUG_ON(sizeof(struct ubifs_ch) != 24);
1939 
1940 	/* Make sure node sizes are 8-byte aligned */
1941 	BUILD_BUG_ON(UBIFS_CH_SZ        & 7);
1942 	BUILD_BUG_ON(UBIFS_INO_NODE_SZ  & 7);
1943 	BUILD_BUG_ON(UBIFS_DENT_NODE_SZ & 7);
1944 	BUILD_BUG_ON(UBIFS_XENT_NODE_SZ & 7);
1945 	BUILD_BUG_ON(UBIFS_DATA_NODE_SZ & 7);
1946 	BUILD_BUG_ON(UBIFS_TRUN_NODE_SZ & 7);
1947 	BUILD_BUG_ON(UBIFS_SB_NODE_SZ   & 7);
1948 	BUILD_BUG_ON(UBIFS_MST_NODE_SZ  & 7);
1949 	BUILD_BUG_ON(UBIFS_REF_NODE_SZ  & 7);
1950 	BUILD_BUG_ON(UBIFS_CS_NODE_SZ   & 7);
1951 	BUILD_BUG_ON(UBIFS_ORPH_NODE_SZ & 7);
1952 
1953 	BUILD_BUG_ON(UBIFS_MAX_DENT_NODE_SZ & 7);
1954 	BUILD_BUG_ON(UBIFS_MAX_XENT_NODE_SZ & 7);
1955 	BUILD_BUG_ON(UBIFS_MAX_DATA_NODE_SZ & 7);
1956 	BUILD_BUG_ON(UBIFS_MAX_INO_NODE_SZ  & 7);
1957 	BUILD_BUG_ON(UBIFS_MAX_NODE_SZ      & 7);
1958 	BUILD_BUG_ON(MIN_WRITE_SZ           & 7);
1959 
1960 	/* Check min. node size */
1961 	BUILD_BUG_ON(UBIFS_INO_NODE_SZ  < MIN_WRITE_SZ);
1962 	BUILD_BUG_ON(UBIFS_DENT_NODE_SZ < MIN_WRITE_SZ);
1963 	BUILD_BUG_ON(UBIFS_XENT_NODE_SZ < MIN_WRITE_SZ);
1964 	BUILD_BUG_ON(UBIFS_TRUN_NODE_SZ < MIN_WRITE_SZ);
1965 
1966 	BUILD_BUG_ON(UBIFS_MAX_DENT_NODE_SZ > UBIFS_MAX_NODE_SZ);
1967 	BUILD_BUG_ON(UBIFS_MAX_XENT_NODE_SZ > UBIFS_MAX_NODE_SZ);
1968 	BUILD_BUG_ON(UBIFS_MAX_DATA_NODE_SZ > UBIFS_MAX_NODE_SZ);
1969 	BUILD_BUG_ON(UBIFS_MAX_INO_NODE_SZ  > UBIFS_MAX_NODE_SZ);
1970 
1971 	/* Defined node sizes */
1972 	BUILD_BUG_ON(UBIFS_SB_NODE_SZ  != 4096);
1973 	BUILD_BUG_ON(UBIFS_MST_NODE_SZ != 512);
1974 	BUILD_BUG_ON(UBIFS_INO_NODE_SZ != 160);
1975 	BUILD_BUG_ON(UBIFS_REF_NODE_SZ != 64);
1976 
1977 	/*
1978 	 * We require that PAGE_CACHE_SIZE is greater-than-or-equal-to
1979 	 * UBIFS_BLOCK_SIZE. It is assumed that both are powers of 2.
1980 	 */
1981 	if (PAGE_CACHE_SIZE < UBIFS_BLOCK_SIZE) {
1982 		ubifs_err("VFS page cache size is %u bytes, but UBIFS requires"
1983 			  " at least 4096 bytes",
1984 			  (unsigned int)PAGE_CACHE_SIZE);
1985 		return -EINVAL;
1986 	}
1987 
1988 	err = register_filesystem(&ubifs_fs_type);
1989 	if (err) {
1990 		ubifs_err("cannot register file system, error %d", err);
1991 		return err;
1992 	}
1993 
1994 	err = -ENOMEM;
1995 	ubifs_inode_slab = kmem_cache_create("ubifs_inode_slab",
1996 				sizeof(struct ubifs_inode), 0,
1997 				SLAB_MEM_SPREAD | SLAB_RECLAIM_ACCOUNT,
1998 				&inode_slab_ctor);
1999 	if (!ubifs_inode_slab)
2000 		goto out_reg;
2001 
2002 	register_shrinker(&ubifs_shrinker_info);
2003 
2004 	err = ubifs_compressors_init();
2005 	if (err)
2006 		goto out_compr;
2007 
2008 	return 0;
2009 
2010 out_compr:
2011 	unregister_shrinker(&ubifs_shrinker_info);
2012 	kmem_cache_destroy(ubifs_inode_slab);
2013 out_reg:
2014 	unregister_filesystem(&ubifs_fs_type);
2015 	return err;
2016 }
2017 /* late_initcall to let compressors initialize first */
2018 late_initcall(ubifs_init);
2019 
2020 static void __exit ubifs_exit(void)
2021 {
2022 	ubifs_assert(list_empty(&ubifs_infos));
2023 	ubifs_assert(atomic_long_read(&ubifs_clean_zn_cnt) == 0);
2024 
2025 	ubifs_compressors_exit();
2026 	unregister_shrinker(&ubifs_shrinker_info);
2027 	kmem_cache_destroy(ubifs_inode_slab);
2028 	unregister_filesystem(&ubifs_fs_type);
2029 }
2030 module_exit(ubifs_exit);
2031 
2032 MODULE_LICENSE("GPL");
2033 MODULE_VERSION(__stringify(UBIFS_VERSION));
2034 MODULE_AUTHOR("Artem Bityutskiy, Adrian Hunter");
2035 MODULE_DESCRIPTION("UBIFS - UBI File System");
2036