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