xref: /openbmc/linux/fs/ubifs/super.c (revision 9d56dd3b083a3bec56e9da35ce07baca81030b03)
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  */
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 && (inode->i_mode & S_IFMT) != S_IFREG)
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_size(c, inode);
98 	return err;
99 }
100 
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 	inode->i_nlink = 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 
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 
275 static void ubifs_destroy_inode(struct inode *inode)
276 {
277 	struct ubifs_inode *ui = ubifs_inode(inode);
278 
279 	kfree(ui->data);
280 	kmem_cache_free(ubifs_inode_slab, inode);
281 }
282 
283 /*
284  * Note, Linux write-back code calls this without 'i_mutex'.
285  */
286 static int ubifs_write_inode(struct inode *inode, int wait)
287 {
288 	int err = 0;
289 	struct ubifs_info *c = inode->i_sb->s_fs_info;
290 	struct ubifs_inode *ui = ubifs_inode(inode);
291 
292 	ubifs_assert(!ui->xattr);
293 	if (is_bad_inode(inode))
294 		return 0;
295 
296 	mutex_lock(&ui->ui_mutex);
297 	/*
298 	 * Due to races between write-back forced by budgeting
299 	 * (see 'sync_some_inodes()') and pdflush write-back, the inode may
300 	 * have already been synchronized, do not do this again. This might
301 	 * also happen if it was synchronized in an VFS operation, e.g.
302 	 * 'ubifs_link()'.
303 	 */
304 	if (!ui->dirty) {
305 		mutex_unlock(&ui->ui_mutex);
306 		return 0;
307 	}
308 
309 	/*
310 	 * As an optimization, do not write orphan inodes to the media just
311 	 * because this is not needed.
312 	 */
313 	dbg_gen("inode %lu, mode %#x, nlink %u",
314 		inode->i_ino, (int)inode->i_mode, inode->i_nlink);
315 	if (inode->i_nlink) {
316 		err = ubifs_jnl_write_inode(c, inode);
317 		if (err)
318 			ubifs_err("can't write inode %lu, error %d",
319 				  inode->i_ino, err);
320 		else
321 			err = dbg_check_inode_size(c, inode, ui->ui_size);
322 	}
323 
324 	ui->dirty = 0;
325 	mutex_unlock(&ui->ui_mutex);
326 	ubifs_release_dirty_inode_budget(c, ui);
327 	return err;
328 }
329 
330 static void ubifs_delete_inode(struct inode *inode)
331 {
332 	int err;
333 	struct ubifs_info *c = inode->i_sb->s_fs_info;
334 	struct ubifs_inode *ui = ubifs_inode(inode);
335 
336 	if (ui->xattr)
337 		/*
338 		 * Extended attribute inode deletions are fully handled in
339 		 * 'ubifs_removexattr()'. These inodes are special and have
340 		 * limited usage, so there is nothing to do here.
341 		 */
342 		goto out;
343 
344 	dbg_gen("inode %lu, mode %#x", inode->i_ino, (int)inode->i_mode);
345 	ubifs_assert(!atomic_read(&inode->i_count));
346 	ubifs_assert(inode->i_nlink == 0);
347 
348 	truncate_inode_pages(&inode->i_data, 0);
349 	if (is_bad_inode(inode))
350 		goto out;
351 
352 	ui->ui_size = inode->i_size = 0;
353 	err = ubifs_jnl_delete_inode(c, inode);
354 	if (err)
355 		/*
356 		 * Worst case we have a lost orphan inode wasting space, so a
357 		 * simple error message is OK here.
358 		 */
359 		ubifs_err("can't delete inode %lu, error %d",
360 			  inode->i_ino, err);
361 
362 out:
363 	if (ui->dirty)
364 		ubifs_release_dirty_inode_budget(c, ui);
365 	else {
366 		/* We've deleted something - clean the "no space" flags */
367 		c->nospace = c->nospace_rp = 0;
368 		smp_wmb();
369 	}
370 	clear_inode(inode);
371 }
372 
373 static void ubifs_dirty_inode(struct inode *inode)
374 {
375 	struct ubifs_inode *ui = ubifs_inode(inode);
376 
377 	ubifs_assert(mutex_is_locked(&ui->ui_mutex));
378 	if (!ui->dirty) {
379 		ui->dirty = 1;
380 		dbg_gen("inode %lu",  inode->i_ino);
381 	}
382 }
383 
384 static int ubifs_statfs(struct dentry *dentry, struct kstatfs *buf)
385 {
386 	struct ubifs_info *c = dentry->d_sb->s_fs_info;
387 	unsigned long long free;
388 	__le32 *uuid = (__le32 *)c->uuid;
389 
390 	free = ubifs_get_free_space(c);
391 	dbg_gen("free space %lld bytes (%lld blocks)",
392 		free, free >> UBIFS_BLOCK_SHIFT);
393 
394 	buf->f_type = UBIFS_SUPER_MAGIC;
395 	buf->f_bsize = UBIFS_BLOCK_SIZE;
396 	buf->f_blocks = c->block_cnt;
397 	buf->f_bfree = free >> UBIFS_BLOCK_SHIFT;
398 	if (free > c->report_rp_size)
399 		buf->f_bavail = (free - c->report_rp_size) >> UBIFS_BLOCK_SHIFT;
400 	else
401 		buf->f_bavail = 0;
402 	buf->f_files = 0;
403 	buf->f_ffree = 0;
404 	buf->f_namelen = UBIFS_MAX_NLEN;
405 	buf->f_fsid.val[0] = le32_to_cpu(uuid[0]) ^ le32_to_cpu(uuid[2]);
406 	buf->f_fsid.val[1] = le32_to_cpu(uuid[1]) ^ le32_to_cpu(uuid[3]);
407 	ubifs_assert(buf->f_bfree <= c->block_cnt);
408 	return 0;
409 }
410 
411 static int ubifs_show_options(struct seq_file *s, struct vfsmount *mnt)
412 {
413 	struct ubifs_info *c = mnt->mnt_sb->s_fs_info;
414 
415 	if (c->mount_opts.unmount_mode == 2)
416 		seq_printf(s, ",fast_unmount");
417 	else if (c->mount_opts.unmount_mode == 1)
418 		seq_printf(s, ",norm_unmount");
419 
420 	if (c->mount_opts.bulk_read == 2)
421 		seq_printf(s, ",bulk_read");
422 	else if (c->mount_opts.bulk_read == 1)
423 		seq_printf(s, ",no_bulk_read");
424 
425 	if (c->mount_opts.chk_data_crc == 2)
426 		seq_printf(s, ",chk_data_crc");
427 	else if (c->mount_opts.chk_data_crc == 1)
428 		seq_printf(s, ",no_chk_data_crc");
429 
430 	if (c->mount_opts.override_compr) {
431 		seq_printf(s, ",compr=%s",
432 			   ubifs_compr_name(c->mount_opts.compr_type));
433 	}
434 
435 	return 0;
436 }
437 
438 static int ubifs_sync_fs(struct super_block *sb, int wait)
439 {
440 	int i, err;
441 	struct ubifs_info *c = sb->s_fs_info;
442 
443 	/*
444 	 * Zero @wait is just an advisory thing to help the file system shove
445 	 * lots of data into the queues, and there will be the second
446 	 * '->sync_fs()' call, with non-zero @wait.
447 	 */
448 	if (!wait)
449 		return 0;
450 
451 	/*
452 	 * Synchronize write buffers, because 'ubifs_run_commit()' does not
453 	 * do this if it waits for an already running commit.
454 	 */
455 	for (i = 0; i < c->jhead_cnt; i++) {
456 		err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
457 		if (err)
458 			return err;
459 	}
460 
461 	/*
462 	 * Strictly speaking, it is not necessary to commit the journal here,
463 	 * synchronizing write-buffers would be enough. But committing makes
464 	 * UBIFS free space predictions much more accurate, so we want to let
465 	 * the user be able to get more accurate results of 'statfs()' after
466 	 * they synchronize the file system.
467 	 */
468 	err = ubifs_run_commit(c);
469 	if (err)
470 		return err;
471 
472 	return ubi_sync(c->vi.ubi_num);
473 }
474 
475 /**
476  * init_constants_early - initialize UBIFS constants.
477  * @c: UBIFS file-system description object
478  *
479  * This function initialize UBIFS constants which do not need the superblock to
480  * be read. It also checks that the UBI volume satisfies basic UBIFS
481  * requirements. Returns zero in case of success and a negative error code in
482  * case of failure.
483  */
484 static int init_constants_early(struct ubifs_info *c)
485 {
486 	if (c->vi.corrupted) {
487 		ubifs_warn("UBI volume is corrupted - read-only mode");
488 		c->ro_media = 1;
489 	}
490 
491 	if (c->di.ro_mode) {
492 		ubifs_msg("read-only UBI device");
493 		c->ro_media = 1;
494 	}
495 
496 	if (c->vi.vol_type == UBI_STATIC_VOLUME) {
497 		ubifs_msg("static UBI volume - read-only mode");
498 		c->ro_media = 1;
499 	}
500 
501 	c->leb_cnt = c->vi.size;
502 	c->leb_size = c->vi.usable_leb_size;
503 	c->half_leb_size = c->leb_size / 2;
504 	c->min_io_size = c->di.min_io_size;
505 	c->min_io_shift = fls(c->min_io_size) - 1;
506 
507 	if (c->leb_size < UBIFS_MIN_LEB_SZ) {
508 		ubifs_err("too small LEBs (%d bytes), min. is %d bytes",
509 			  c->leb_size, UBIFS_MIN_LEB_SZ);
510 		return -EINVAL;
511 	}
512 
513 	if (c->leb_cnt < UBIFS_MIN_LEB_CNT) {
514 		ubifs_err("too few LEBs (%d), min. is %d",
515 			  c->leb_cnt, UBIFS_MIN_LEB_CNT);
516 		return -EINVAL;
517 	}
518 
519 	if (!is_power_of_2(c->min_io_size)) {
520 		ubifs_err("bad min. I/O size %d", c->min_io_size);
521 		return -EINVAL;
522 	}
523 
524 	/*
525 	 * UBIFS aligns all node to 8-byte boundary, so to make function in
526 	 * io.c simpler, assume minimum I/O unit size to be 8 bytes if it is
527 	 * less than 8.
528 	 */
529 	if (c->min_io_size < 8) {
530 		c->min_io_size = 8;
531 		c->min_io_shift = 3;
532 	}
533 
534 	c->ref_node_alsz = ALIGN(UBIFS_REF_NODE_SZ, c->min_io_size);
535 	c->mst_node_alsz = ALIGN(UBIFS_MST_NODE_SZ, c->min_io_size);
536 
537 	/*
538 	 * Initialize node length ranges which are mostly needed for node
539 	 * length validation.
540 	 */
541 	c->ranges[UBIFS_PAD_NODE].len  = UBIFS_PAD_NODE_SZ;
542 	c->ranges[UBIFS_SB_NODE].len   = UBIFS_SB_NODE_SZ;
543 	c->ranges[UBIFS_MST_NODE].len  = UBIFS_MST_NODE_SZ;
544 	c->ranges[UBIFS_REF_NODE].len  = UBIFS_REF_NODE_SZ;
545 	c->ranges[UBIFS_TRUN_NODE].len = UBIFS_TRUN_NODE_SZ;
546 	c->ranges[UBIFS_CS_NODE].len   = UBIFS_CS_NODE_SZ;
547 
548 	c->ranges[UBIFS_INO_NODE].min_len  = UBIFS_INO_NODE_SZ;
549 	c->ranges[UBIFS_INO_NODE].max_len  = UBIFS_MAX_INO_NODE_SZ;
550 	c->ranges[UBIFS_ORPH_NODE].min_len =
551 				UBIFS_ORPH_NODE_SZ + sizeof(__le64);
552 	c->ranges[UBIFS_ORPH_NODE].max_len = c->leb_size;
553 	c->ranges[UBIFS_DENT_NODE].min_len = UBIFS_DENT_NODE_SZ;
554 	c->ranges[UBIFS_DENT_NODE].max_len = UBIFS_MAX_DENT_NODE_SZ;
555 	c->ranges[UBIFS_XENT_NODE].min_len = UBIFS_XENT_NODE_SZ;
556 	c->ranges[UBIFS_XENT_NODE].max_len = UBIFS_MAX_XENT_NODE_SZ;
557 	c->ranges[UBIFS_DATA_NODE].min_len = UBIFS_DATA_NODE_SZ;
558 	c->ranges[UBIFS_DATA_NODE].max_len = UBIFS_MAX_DATA_NODE_SZ;
559 	/*
560 	 * Minimum indexing node size is amended later when superblock is
561 	 * read and the key length is known.
562 	 */
563 	c->ranges[UBIFS_IDX_NODE].min_len = UBIFS_IDX_NODE_SZ + UBIFS_BRANCH_SZ;
564 	/*
565 	 * Maximum indexing node size is amended later when superblock is
566 	 * read and the fanout is known.
567 	 */
568 	c->ranges[UBIFS_IDX_NODE].max_len = INT_MAX;
569 
570 	/*
571 	 * Initialize dead and dark LEB space watermarks. See gc.c for comments
572 	 * about these values.
573 	 */
574 	c->dead_wm = ALIGN(MIN_WRITE_SZ, c->min_io_size);
575 	c->dark_wm = ALIGN(UBIFS_MAX_NODE_SZ, c->min_io_size);
576 
577 	/*
578 	 * Calculate how many bytes would be wasted at the end of LEB if it was
579 	 * fully filled with data nodes of maximum size. This is used in
580 	 * calculations when reporting free space.
581 	 */
582 	c->leb_overhead = c->leb_size % UBIFS_MAX_DATA_NODE_SZ;
583 
584 	/* Buffer size for bulk-reads */
585 	c->max_bu_buf_len = UBIFS_MAX_BULK_READ * UBIFS_MAX_DATA_NODE_SZ;
586 	if (c->max_bu_buf_len > c->leb_size)
587 		c->max_bu_buf_len = c->leb_size;
588 	return 0;
589 }
590 
591 /**
592  * bud_wbuf_callback - bud LEB write-buffer synchronization call-back.
593  * @c: UBIFS file-system description object
594  * @lnum: LEB the write-buffer was synchronized to
595  * @free: how many free bytes left in this LEB
596  * @pad: how many bytes were padded
597  *
598  * This is a callback function which is called by the I/O unit when the
599  * write-buffer is synchronized. We need this to correctly maintain space
600  * accounting in bud logical eraseblocks. This function returns zero in case of
601  * success and a negative error code in case of failure.
602  *
603  * This function actually belongs to the journal, but we keep it here because
604  * we want to keep it static.
605  */
606 static int bud_wbuf_callback(struct ubifs_info *c, int lnum, int free, int pad)
607 {
608 	return ubifs_update_one_lp(c, lnum, free, pad, 0, 0);
609 }
610 
611 /*
612  * init_constants_sb - initialize UBIFS constants.
613  * @c: UBIFS file-system description object
614  *
615  * This is a helper function which initializes various UBIFS constants after
616  * the superblock has been read. It also checks various UBIFS parameters and
617  * makes sure they are all right. Returns zero in case of success and a
618  * negative error code in case of failure.
619  */
620 static int init_constants_sb(struct ubifs_info *c)
621 {
622 	int tmp, err;
623 	long long tmp64;
624 
625 	c->main_bytes = (long long)c->main_lebs * c->leb_size;
626 	c->max_znode_sz = sizeof(struct ubifs_znode) +
627 				c->fanout * sizeof(struct ubifs_zbranch);
628 
629 	tmp = ubifs_idx_node_sz(c, 1);
630 	c->ranges[UBIFS_IDX_NODE].min_len = tmp;
631 	c->min_idx_node_sz = ALIGN(tmp, 8);
632 
633 	tmp = ubifs_idx_node_sz(c, c->fanout);
634 	c->ranges[UBIFS_IDX_NODE].max_len = tmp;
635 	c->max_idx_node_sz = ALIGN(tmp, 8);
636 
637 	/* Make sure LEB size is large enough to fit full commit */
638 	tmp = UBIFS_CS_NODE_SZ + UBIFS_REF_NODE_SZ * c->jhead_cnt;
639 	tmp = ALIGN(tmp, c->min_io_size);
640 	if (tmp > c->leb_size) {
641 		dbg_err("too small LEB size %d, at least %d needed",
642 			c->leb_size, tmp);
643 		return -EINVAL;
644 	}
645 
646 	/*
647 	 * Make sure that the log is large enough to fit reference nodes for
648 	 * all buds plus one reserved LEB.
649 	 */
650 	tmp64 = c->max_bud_bytes + c->leb_size - 1;
651 	c->max_bud_cnt = div_u64(tmp64, c->leb_size);
652 	tmp = (c->ref_node_alsz * c->max_bud_cnt + c->leb_size - 1);
653 	tmp /= c->leb_size;
654 	tmp += 1;
655 	if (c->log_lebs < tmp) {
656 		dbg_err("too small log %d LEBs, required min. %d LEBs",
657 			c->log_lebs, tmp);
658 		return -EINVAL;
659 	}
660 
661 	/*
662 	 * When budgeting we assume worst-case scenarios when the pages are not
663 	 * be compressed and direntries are of the maximum size.
664 	 *
665 	 * Note, data, which may be stored in inodes is budgeted separately, so
666 	 * it is not included into 'c->inode_budget'.
667 	 */
668 	c->page_budget = UBIFS_MAX_DATA_NODE_SZ * UBIFS_BLOCKS_PER_PAGE;
669 	c->inode_budget = UBIFS_INO_NODE_SZ;
670 	c->dent_budget = UBIFS_MAX_DENT_NODE_SZ;
671 
672 	/*
673 	 * When the amount of flash space used by buds becomes
674 	 * 'c->max_bud_bytes', UBIFS just blocks all writers and starts commit.
675 	 * The writers are unblocked when the commit is finished. To avoid
676 	 * writers to be blocked UBIFS initiates background commit in advance,
677 	 * when number of bud bytes becomes above the limit defined below.
678 	 */
679 	c->bg_bud_bytes = (c->max_bud_bytes * 13) >> 4;
680 
681 	/*
682 	 * Ensure minimum journal size. All the bytes in the journal heads are
683 	 * considered to be used, when calculating the current journal usage.
684 	 * Consequently, if the journal is too small, UBIFS will treat it as
685 	 * always full.
686 	 */
687 	tmp64 = (long long)(c->jhead_cnt + 1) * c->leb_size + 1;
688 	if (c->bg_bud_bytes < tmp64)
689 		c->bg_bud_bytes = tmp64;
690 	if (c->max_bud_bytes < tmp64 + c->leb_size)
691 		c->max_bud_bytes = tmp64 + c->leb_size;
692 
693 	err = ubifs_calc_lpt_geom(c);
694 	if (err)
695 		return err;
696 
697 	/* Initialize effective LEB size used in budgeting calculations */
698 	c->idx_leb_size = c->leb_size - c->max_idx_node_sz;
699 	return 0;
700 }
701 
702 /*
703  * init_constants_master - initialize UBIFS constants.
704  * @c: UBIFS file-system description object
705  *
706  * This is a helper function which initializes various UBIFS constants after
707  * the master node has been read. It also checks various UBIFS parameters and
708  * makes sure they are all right.
709  */
710 static void init_constants_master(struct ubifs_info *c)
711 {
712 	long long tmp64;
713 
714 	c->min_idx_lebs = ubifs_calc_min_idx_lebs(c);
715 	c->report_rp_size = ubifs_reported_space(c, c->rp_size);
716 
717 	/*
718 	 * Calculate total amount of FS blocks. This number is not used
719 	 * internally because it does not make much sense for UBIFS, but it is
720 	 * necessary to report something for the 'statfs()' call.
721 	 *
722 	 * Subtract the LEB reserved for GC, the LEB which is reserved for
723 	 * deletions, minimum LEBs for the index, and assume only one journal
724 	 * head is available.
725 	 */
726 	tmp64 = c->main_lebs - 1 - 1 - MIN_INDEX_LEBS - c->jhead_cnt + 1;
727 	tmp64 *= (long long)c->leb_size - c->leb_overhead;
728 	tmp64 = ubifs_reported_space(c, tmp64);
729 	c->block_cnt = tmp64 >> UBIFS_BLOCK_SHIFT;
730 }
731 
732 /**
733  * take_gc_lnum - reserve GC LEB.
734  * @c: UBIFS file-system description object
735  *
736  * This function ensures that the LEB reserved for garbage collection is marked
737  * as "taken" in lprops. We also have to set free space to LEB size and dirty
738  * space to zero, because lprops may contain out-of-date information if the
739  * file-system was un-mounted before it has been committed. This function
740  * returns zero in case of success and a negative error code in case of
741  * failure.
742  */
743 static int take_gc_lnum(struct ubifs_info *c)
744 {
745 	int err;
746 
747 	if (c->gc_lnum == -1) {
748 		ubifs_err("no LEB for GC");
749 		return -EINVAL;
750 	}
751 
752 	/* And we have to tell lprops that this LEB is taken */
753 	err = ubifs_change_one_lp(c, c->gc_lnum, c->leb_size, 0,
754 				  LPROPS_TAKEN, 0, 0);
755 	return err;
756 }
757 
758 /**
759  * alloc_wbufs - allocate write-buffers.
760  * @c: UBIFS file-system description object
761  *
762  * This helper function allocates and initializes UBIFS write-buffers. Returns
763  * zero in case of success and %-ENOMEM in case of failure.
764  */
765 static int alloc_wbufs(struct ubifs_info *c)
766 {
767 	int i, err;
768 
769 	c->jheads = kzalloc(c->jhead_cnt * sizeof(struct ubifs_jhead),
770 			   GFP_KERNEL);
771 	if (!c->jheads)
772 		return -ENOMEM;
773 
774 	/* Initialize journal heads */
775 	for (i = 0; i < c->jhead_cnt; i++) {
776 		INIT_LIST_HEAD(&c->jheads[i].buds_list);
777 		err = ubifs_wbuf_init(c, &c->jheads[i].wbuf);
778 		if (err)
779 			return err;
780 
781 		c->jheads[i].wbuf.sync_callback = &bud_wbuf_callback;
782 		c->jheads[i].wbuf.jhead = i;
783 	}
784 
785 	c->jheads[BASEHD].wbuf.dtype = UBI_SHORTTERM;
786 	/*
787 	 * Garbage Collector head likely contains long-term data and
788 	 * does not need to be synchronized by timer.
789 	 */
790 	c->jheads[GCHD].wbuf.dtype = UBI_LONGTERM;
791 	c->jheads[GCHD].wbuf.no_timer = 1;
792 
793 	return 0;
794 }
795 
796 /**
797  * free_wbufs - free write-buffers.
798  * @c: UBIFS file-system description object
799  */
800 static void free_wbufs(struct ubifs_info *c)
801 {
802 	int i;
803 
804 	if (c->jheads) {
805 		for (i = 0; i < c->jhead_cnt; i++) {
806 			kfree(c->jheads[i].wbuf.buf);
807 			kfree(c->jheads[i].wbuf.inodes);
808 		}
809 		kfree(c->jheads);
810 		c->jheads = NULL;
811 	}
812 }
813 
814 /**
815  * free_orphans - free orphans.
816  * @c: UBIFS file-system description object
817  */
818 static void free_orphans(struct ubifs_info *c)
819 {
820 	struct ubifs_orphan *orph;
821 
822 	while (c->orph_dnext) {
823 		orph = c->orph_dnext;
824 		c->orph_dnext = orph->dnext;
825 		list_del(&orph->list);
826 		kfree(orph);
827 	}
828 
829 	while (!list_empty(&c->orph_list)) {
830 		orph = list_entry(c->orph_list.next, struct ubifs_orphan, list);
831 		list_del(&orph->list);
832 		kfree(orph);
833 		dbg_err("orphan list not empty at unmount");
834 	}
835 
836 	vfree(c->orph_buf);
837 	c->orph_buf = NULL;
838 }
839 
840 /**
841  * free_buds - free per-bud objects.
842  * @c: UBIFS file-system description object
843  */
844 static void free_buds(struct ubifs_info *c)
845 {
846 	struct rb_node *this = c->buds.rb_node;
847 	struct ubifs_bud *bud;
848 
849 	while (this) {
850 		if (this->rb_left)
851 			this = this->rb_left;
852 		else if (this->rb_right)
853 			this = this->rb_right;
854 		else {
855 			bud = rb_entry(this, struct ubifs_bud, rb);
856 			this = rb_parent(this);
857 			if (this) {
858 				if (this->rb_left == &bud->rb)
859 					this->rb_left = NULL;
860 				else
861 					this->rb_right = NULL;
862 			}
863 			kfree(bud);
864 		}
865 	}
866 }
867 
868 /**
869  * check_volume_empty - check if the UBI volume is empty.
870  * @c: UBIFS file-system description object
871  *
872  * This function checks if the UBIFS volume is empty by looking if its LEBs are
873  * mapped or not. The result of checking is stored in the @c->empty variable.
874  * Returns zero in case of success and a negative error code in case of
875  * failure.
876  */
877 static int check_volume_empty(struct ubifs_info *c)
878 {
879 	int lnum, err;
880 
881 	c->empty = 1;
882 	for (lnum = 0; lnum < c->leb_cnt; lnum++) {
883 		err = ubi_is_mapped(c->ubi, lnum);
884 		if (unlikely(err < 0))
885 			return err;
886 		if (err == 1) {
887 			c->empty = 0;
888 			break;
889 		}
890 
891 		cond_resched();
892 	}
893 
894 	return 0;
895 }
896 
897 /*
898  * UBIFS mount options.
899  *
900  * Opt_fast_unmount: do not run a journal commit before un-mounting
901  * Opt_norm_unmount: run a journal commit before un-mounting
902  * Opt_bulk_read: enable bulk-reads
903  * Opt_no_bulk_read: disable bulk-reads
904  * Opt_chk_data_crc: check CRCs when reading data nodes
905  * Opt_no_chk_data_crc: do not check CRCs when reading data nodes
906  * Opt_override_compr: override default compressor
907  * Opt_err: just end of array marker
908  */
909 enum {
910 	Opt_fast_unmount,
911 	Opt_norm_unmount,
912 	Opt_bulk_read,
913 	Opt_no_bulk_read,
914 	Opt_chk_data_crc,
915 	Opt_no_chk_data_crc,
916 	Opt_override_compr,
917 	Opt_err,
918 };
919 
920 static const match_table_t tokens = {
921 	{Opt_fast_unmount, "fast_unmount"},
922 	{Opt_norm_unmount, "norm_unmount"},
923 	{Opt_bulk_read, "bulk_read"},
924 	{Opt_no_bulk_read, "no_bulk_read"},
925 	{Opt_chk_data_crc, "chk_data_crc"},
926 	{Opt_no_chk_data_crc, "no_chk_data_crc"},
927 	{Opt_override_compr, "compr=%s"},
928 	{Opt_err, NULL},
929 };
930 
931 /**
932  * parse_standard_option - parse a standard mount option.
933  * @option: the option to parse
934  *
935  * Normally, standard mount options like "sync" are passed to file-systems as
936  * flags. However, when a "rootflags=" kernel boot parameter is used, they may
937  * be present in the options string. This function tries to deal with this
938  * situation and parse standard options. Returns 0 if the option was not
939  * recognized, and the corresponding integer flag if it was.
940  *
941  * UBIFS is only interested in the "sync" option, so do not check for anything
942  * else.
943  */
944 static int parse_standard_option(const char *option)
945 {
946 	ubifs_msg("parse %s", option);
947 	if (!strcmp(option, "sync"))
948 		return MS_SYNCHRONOUS;
949 	return 0;
950 }
951 
952 /**
953  * ubifs_parse_options - parse mount parameters.
954  * @c: UBIFS file-system description object
955  * @options: parameters to parse
956  * @is_remount: non-zero if this is FS re-mount
957  *
958  * This function parses UBIFS mount options and returns zero in case success
959  * and a negative error code in case of failure.
960  */
961 static int ubifs_parse_options(struct ubifs_info *c, char *options,
962 			       int is_remount)
963 {
964 	char *p;
965 	substring_t args[MAX_OPT_ARGS];
966 
967 	if (!options)
968 		return 0;
969 
970 	while ((p = strsep(&options, ","))) {
971 		int token;
972 
973 		if (!*p)
974 			continue;
975 
976 		token = match_token(p, tokens, args);
977 		switch (token) {
978 		/*
979 		 * %Opt_fast_unmount and %Opt_norm_unmount options are ignored.
980 		 * We accept them in order to be backward-compatible. But this
981 		 * should be removed at some point.
982 		 */
983 		case Opt_fast_unmount:
984 			c->mount_opts.unmount_mode = 2;
985 			break;
986 		case Opt_norm_unmount:
987 			c->mount_opts.unmount_mode = 1;
988 			break;
989 		case Opt_bulk_read:
990 			c->mount_opts.bulk_read = 2;
991 			c->bulk_read = 1;
992 			break;
993 		case Opt_no_bulk_read:
994 			c->mount_opts.bulk_read = 1;
995 			c->bulk_read = 0;
996 			break;
997 		case Opt_chk_data_crc:
998 			c->mount_opts.chk_data_crc = 2;
999 			c->no_chk_data_crc = 0;
1000 			break;
1001 		case Opt_no_chk_data_crc:
1002 			c->mount_opts.chk_data_crc = 1;
1003 			c->no_chk_data_crc = 1;
1004 			break;
1005 		case Opt_override_compr:
1006 		{
1007 			char *name = match_strdup(&args[0]);
1008 
1009 			if (!name)
1010 				return -ENOMEM;
1011 			if (!strcmp(name, "none"))
1012 				c->mount_opts.compr_type = UBIFS_COMPR_NONE;
1013 			else if (!strcmp(name, "lzo"))
1014 				c->mount_opts.compr_type = UBIFS_COMPR_LZO;
1015 			else if (!strcmp(name, "zlib"))
1016 				c->mount_opts.compr_type = UBIFS_COMPR_ZLIB;
1017 			else {
1018 				ubifs_err("unknown compressor \"%s\"", name);
1019 				kfree(name);
1020 				return -EINVAL;
1021 			}
1022 			kfree(name);
1023 			c->mount_opts.override_compr = 1;
1024 			c->default_compr = c->mount_opts.compr_type;
1025 			break;
1026 		}
1027 		default:
1028 		{
1029 			unsigned long flag;
1030 			struct super_block *sb = c->vfs_sb;
1031 
1032 			flag = parse_standard_option(p);
1033 			if (!flag) {
1034 				ubifs_err("unrecognized mount option \"%s\" "
1035 					  "or missing value", p);
1036 				return -EINVAL;
1037 			}
1038 			sb->s_flags |= flag;
1039 			break;
1040 		}
1041 		}
1042 	}
1043 
1044 	return 0;
1045 }
1046 
1047 /**
1048  * destroy_journal - destroy journal data structures.
1049  * @c: UBIFS file-system description object
1050  *
1051  * This function destroys journal data structures including those that may have
1052  * been created by recovery functions.
1053  */
1054 static void destroy_journal(struct ubifs_info *c)
1055 {
1056 	while (!list_empty(&c->unclean_leb_list)) {
1057 		struct ubifs_unclean_leb *ucleb;
1058 
1059 		ucleb = list_entry(c->unclean_leb_list.next,
1060 				   struct ubifs_unclean_leb, list);
1061 		list_del(&ucleb->list);
1062 		kfree(ucleb);
1063 	}
1064 	while (!list_empty(&c->old_buds)) {
1065 		struct ubifs_bud *bud;
1066 
1067 		bud = list_entry(c->old_buds.next, struct ubifs_bud, list);
1068 		list_del(&bud->list);
1069 		kfree(bud);
1070 	}
1071 	ubifs_destroy_idx_gc(c);
1072 	ubifs_destroy_size_tree(c);
1073 	ubifs_tnc_close(c);
1074 	free_buds(c);
1075 }
1076 
1077 /**
1078  * bu_init - initialize bulk-read information.
1079  * @c: UBIFS file-system description object
1080  */
1081 static void bu_init(struct ubifs_info *c)
1082 {
1083 	ubifs_assert(c->bulk_read == 1);
1084 
1085 	if (c->bu.buf)
1086 		return; /* Already initialized */
1087 
1088 again:
1089 	c->bu.buf = kmalloc(c->max_bu_buf_len, GFP_KERNEL | __GFP_NOWARN);
1090 	if (!c->bu.buf) {
1091 		if (c->max_bu_buf_len > UBIFS_KMALLOC_OK) {
1092 			c->max_bu_buf_len = UBIFS_KMALLOC_OK;
1093 			goto again;
1094 		}
1095 
1096 		/* Just disable bulk-read */
1097 		ubifs_warn("Cannot allocate %d bytes of memory for bulk-read, "
1098 			   "disabling it", c->max_bu_buf_len);
1099 		c->mount_opts.bulk_read = 1;
1100 		c->bulk_read = 0;
1101 		return;
1102 	}
1103 }
1104 
1105 /**
1106  * check_free_space - check if there is enough free space to mount.
1107  * @c: UBIFS file-system description object
1108  *
1109  * This function makes sure UBIFS has enough free space to be mounted in
1110  * read/write mode. UBIFS must always have some free space to allow deletions.
1111  */
1112 static int check_free_space(struct ubifs_info *c)
1113 {
1114 	ubifs_assert(c->dark_wm > 0);
1115 	if (c->lst.total_free + c->lst.total_dirty < c->dark_wm) {
1116 		ubifs_err("insufficient free space to mount in read/write mode");
1117 		dbg_dump_budg(c);
1118 		dbg_dump_lprops(c);
1119 		return -ENOSPC;
1120 	}
1121 	return 0;
1122 }
1123 
1124 /**
1125  * mount_ubifs - mount UBIFS file-system.
1126  * @c: UBIFS file-system description object
1127  *
1128  * This function mounts UBIFS file system. Returns zero in case of success and
1129  * a negative error code in case of failure.
1130  *
1131  * Note, the function does not de-allocate resources it it fails half way
1132  * through, and the caller has to do this instead.
1133  */
1134 static int mount_ubifs(struct ubifs_info *c)
1135 {
1136 	struct super_block *sb = c->vfs_sb;
1137 	int err, mounted_read_only = (sb->s_flags & MS_RDONLY);
1138 	long long x;
1139 	size_t sz;
1140 
1141 	err = init_constants_early(c);
1142 	if (err)
1143 		return err;
1144 
1145 	err = ubifs_debugging_init(c);
1146 	if (err)
1147 		return err;
1148 
1149 	err = check_volume_empty(c);
1150 	if (err)
1151 		goto out_free;
1152 
1153 	if (c->empty && (mounted_read_only || c->ro_media)) {
1154 		/*
1155 		 * This UBI volume is empty, and read-only, or the file system
1156 		 * is mounted read-only - we cannot format it.
1157 		 */
1158 		ubifs_err("can't format empty UBI volume: read-only %s",
1159 			  c->ro_media ? "UBI volume" : "mount");
1160 		err = -EROFS;
1161 		goto out_free;
1162 	}
1163 
1164 	if (c->ro_media && !mounted_read_only) {
1165 		ubifs_err("cannot mount read-write - read-only media");
1166 		err = -EROFS;
1167 		goto out_free;
1168 	}
1169 
1170 	/*
1171 	 * The requirement for the buffer is that it should fit indexing B-tree
1172 	 * height amount of integers. We assume the height if the TNC tree will
1173 	 * never exceed 64.
1174 	 */
1175 	err = -ENOMEM;
1176 	c->bottom_up_buf = kmalloc(BOTTOM_UP_HEIGHT * sizeof(int), GFP_KERNEL);
1177 	if (!c->bottom_up_buf)
1178 		goto out_free;
1179 
1180 	c->sbuf = vmalloc(c->leb_size);
1181 	if (!c->sbuf)
1182 		goto out_free;
1183 
1184 	if (!mounted_read_only) {
1185 		c->ileb_buf = vmalloc(c->leb_size);
1186 		if (!c->ileb_buf)
1187 			goto out_free;
1188 	}
1189 
1190 	if (c->bulk_read == 1)
1191 		bu_init(c);
1192 
1193 	/*
1194 	 * We have to check all CRCs, even for data nodes, when we mount the FS
1195 	 * (specifically, when we are replaying).
1196 	 */
1197 	c->always_chk_crc = 1;
1198 
1199 	err = ubifs_read_superblock(c);
1200 	if (err)
1201 		goto out_free;
1202 
1203 	/*
1204 	 * Make sure the compressor which is set as default in the superblock
1205 	 * or overridden by mount options is actually compiled in.
1206 	 */
1207 	if (!ubifs_compr_present(c->default_compr)) {
1208 		ubifs_err("'compressor \"%s\" is not compiled in",
1209 			  ubifs_compr_name(c->default_compr));
1210 		err = -ENOTSUPP;
1211 		goto out_free;
1212 	}
1213 
1214 	err = init_constants_sb(c);
1215 	if (err)
1216 		goto out_free;
1217 
1218 	sz = ALIGN(c->max_idx_node_sz, c->min_io_size);
1219 	sz = ALIGN(sz + c->max_idx_node_sz, c->min_io_size);
1220 	c->cbuf = kmalloc(sz, GFP_NOFS);
1221 	if (!c->cbuf) {
1222 		err = -ENOMEM;
1223 		goto out_free;
1224 	}
1225 
1226 	sprintf(c->bgt_name, BGT_NAME_PATTERN, c->vi.ubi_num, c->vi.vol_id);
1227 	if (!mounted_read_only) {
1228 		err = alloc_wbufs(c);
1229 		if (err)
1230 			goto out_cbuf;
1231 
1232 		/* Create background thread */
1233 		c->bgt = kthread_create(ubifs_bg_thread, c, "%s", c->bgt_name);
1234 		if (IS_ERR(c->bgt)) {
1235 			err = PTR_ERR(c->bgt);
1236 			c->bgt = NULL;
1237 			ubifs_err("cannot spawn \"%s\", error %d",
1238 				  c->bgt_name, err);
1239 			goto out_wbufs;
1240 		}
1241 		wake_up_process(c->bgt);
1242 	}
1243 
1244 	err = ubifs_read_master(c);
1245 	if (err)
1246 		goto out_master;
1247 
1248 	init_constants_master(c);
1249 
1250 	if ((c->mst_node->flags & cpu_to_le32(UBIFS_MST_DIRTY)) != 0) {
1251 		ubifs_msg("recovery needed");
1252 		c->need_recovery = 1;
1253 		if (!mounted_read_only) {
1254 			err = ubifs_recover_inl_heads(c, c->sbuf);
1255 			if (err)
1256 				goto out_master;
1257 		}
1258 	} else if (!mounted_read_only) {
1259 		/*
1260 		 * Set the "dirty" flag so that if we reboot uncleanly we
1261 		 * will notice this immediately on the next mount.
1262 		 */
1263 		c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
1264 		err = ubifs_write_master(c);
1265 		if (err)
1266 			goto out_master;
1267 	}
1268 
1269 	err = ubifs_lpt_init(c, 1, !mounted_read_only);
1270 	if (err)
1271 		goto out_lpt;
1272 
1273 	err = dbg_check_idx_size(c, c->old_idx_sz);
1274 	if (err)
1275 		goto out_lpt;
1276 
1277 	err = ubifs_replay_journal(c);
1278 	if (err)
1279 		goto out_journal;
1280 
1281 	/* Calculate 'min_idx_lebs' after journal replay */
1282 	c->min_idx_lebs = ubifs_calc_min_idx_lebs(c);
1283 
1284 	err = ubifs_mount_orphans(c, c->need_recovery, mounted_read_only);
1285 	if (err)
1286 		goto out_orphans;
1287 
1288 	if (!mounted_read_only) {
1289 		int lnum;
1290 
1291 		err = check_free_space(c);
1292 		if (err)
1293 			goto out_orphans;
1294 
1295 		/* Check for enough log space */
1296 		lnum = c->lhead_lnum + 1;
1297 		if (lnum >= UBIFS_LOG_LNUM + c->log_lebs)
1298 			lnum = UBIFS_LOG_LNUM;
1299 		if (lnum == c->ltail_lnum) {
1300 			err = ubifs_consolidate_log(c);
1301 			if (err)
1302 				goto out_orphans;
1303 		}
1304 
1305 		if (c->need_recovery) {
1306 			err = ubifs_recover_size(c);
1307 			if (err)
1308 				goto out_orphans;
1309 			err = ubifs_rcvry_gc_commit(c);
1310 		} else {
1311 			err = take_gc_lnum(c);
1312 			if (err)
1313 				goto out_orphans;
1314 
1315 			/*
1316 			 * GC LEB may contain garbage if there was an unclean
1317 			 * reboot, and it should be un-mapped.
1318 			 */
1319 			err = ubifs_leb_unmap(c, c->gc_lnum);
1320 			if (err)
1321 				return err;
1322 		}
1323 
1324 		err = dbg_check_lprops(c);
1325 		if (err)
1326 			goto out_orphans;
1327 	} else if (c->need_recovery) {
1328 		err = ubifs_recover_size(c);
1329 		if (err)
1330 			goto out_orphans;
1331 	} else {
1332 		/*
1333 		 * Even if we mount read-only, we have to set space in GC LEB
1334 		 * to proper value because this affects UBIFS free space
1335 		 * reporting. We do not want to have a situation when
1336 		 * re-mounting from R/O to R/W changes amount of free space.
1337 		 */
1338 		err = take_gc_lnum(c);
1339 		if (err)
1340 			goto out_orphans;
1341 	}
1342 
1343 	spin_lock(&ubifs_infos_lock);
1344 	list_add_tail(&c->infos_list, &ubifs_infos);
1345 	spin_unlock(&ubifs_infos_lock);
1346 
1347 	if (c->need_recovery) {
1348 		if (mounted_read_only)
1349 			ubifs_msg("recovery deferred");
1350 		else {
1351 			c->need_recovery = 0;
1352 			ubifs_msg("recovery completed");
1353 			/*
1354 			 * GC LEB has to be empty and taken at this point. But
1355 			 * the journal head LEBs may also be accounted as
1356 			 * "empty taken" if they are empty.
1357 			 */
1358 			ubifs_assert(c->lst.taken_empty_lebs > 0);
1359 		}
1360 	} else
1361 		ubifs_assert(c->lst.taken_empty_lebs > 0);
1362 
1363 	err = dbg_check_filesystem(c);
1364 	if (err)
1365 		goto out_infos;
1366 
1367 	err = dbg_debugfs_init_fs(c);
1368 	if (err)
1369 		goto out_infos;
1370 
1371 	c->always_chk_crc = 0;
1372 
1373 	ubifs_msg("mounted UBI device %d, volume %d, name \"%s\"",
1374 		  c->vi.ubi_num, c->vi.vol_id, c->vi.name);
1375 	if (mounted_read_only)
1376 		ubifs_msg("mounted read-only");
1377 	x = (long long)c->main_lebs * c->leb_size;
1378 	ubifs_msg("file system size:   %lld bytes (%lld KiB, %lld MiB, %d "
1379 		  "LEBs)", x, x >> 10, x >> 20, c->main_lebs);
1380 	x = (long long)c->log_lebs * c->leb_size + c->max_bud_bytes;
1381 	ubifs_msg("journal size:       %lld bytes (%lld KiB, %lld MiB, %d "
1382 		  "LEBs)", x, x >> 10, x >> 20, c->log_lebs + c->max_bud_cnt);
1383 	ubifs_msg("media format:       w%d/r%d (latest is w%d/r%d)",
1384 		  c->fmt_version, c->ro_compat_version,
1385 		  UBIFS_FORMAT_VERSION, UBIFS_RO_COMPAT_VERSION);
1386 	ubifs_msg("default compressor: %s", ubifs_compr_name(c->default_compr));
1387 	ubifs_msg("reserved for root:  %llu bytes (%llu KiB)",
1388 		c->report_rp_size, c->report_rp_size >> 10);
1389 
1390 	dbg_msg("compiled on:         " __DATE__ " at " __TIME__);
1391 	dbg_msg("min. I/O unit size:  %d bytes", c->min_io_size);
1392 	dbg_msg("LEB size:            %d bytes (%d KiB)",
1393 		c->leb_size, c->leb_size >> 10);
1394 	dbg_msg("data journal heads:  %d",
1395 		c->jhead_cnt - NONDATA_JHEADS_CNT);
1396 	dbg_msg("UUID:                %pUB", c->uuid);
1397 	dbg_msg("big_lpt              %d", c->big_lpt);
1398 	dbg_msg("log LEBs:            %d (%d - %d)",
1399 		c->log_lebs, UBIFS_LOG_LNUM, c->log_last);
1400 	dbg_msg("LPT area LEBs:       %d (%d - %d)",
1401 		c->lpt_lebs, c->lpt_first, c->lpt_last);
1402 	dbg_msg("orphan area LEBs:    %d (%d - %d)",
1403 		c->orph_lebs, c->orph_first, c->orph_last);
1404 	dbg_msg("main area LEBs:      %d (%d - %d)",
1405 		c->main_lebs, c->main_first, c->leb_cnt - 1);
1406 	dbg_msg("index LEBs:          %d", c->lst.idx_lebs);
1407 	dbg_msg("total index bytes:   %lld (%lld KiB, %lld MiB)",
1408 		c->old_idx_sz, c->old_idx_sz >> 10, c->old_idx_sz >> 20);
1409 	dbg_msg("key hash type:       %d", c->key_hash_type);
1410 	dbg_msg("tree fanout:         %d", c->fanout);
1411 	dbg_msg("reserved GC LEB:     %d", c->gc_lnum);
1412 	dbg_msg("first main LEB:      %d", c->main_first);
1413 	dbg_msg("max. znode size      %d", c->max_znode_sz);
1414 	dbg_msg("max. index node size %d", c->max_idx_node_sz);
1415 	dbg_msg("node sizes:          data %zu, inode %zu, dentry %zu",
1416 		UBIFS_DATA_NODE_SZ, UBIFS_INO_NODE_SZ, UBIFS_DENT_NODE_SZ);
1417 	dbg_msg("node sizes:          trun %zu, sb %zu, master %zu",
1418 		UBIFS_TRUN_NODE_SZ, UBIFS_SB_NODE_SZ, UBIFS_MST_NODE_SZ);
1419 	dbg_msg("node sizes:          ref %zu, cmt. start %zu, orph %zu",
1420 		UBIFS_REF_NODE_SZ, UBIFS_CS_NODE_SZ, UBIFS_ORPH_NODE_SZ);
1421 	dbg_msg("max. node sizes:     data %zu, inode %zu dentry %zu",
1422 	        UBIFS_MAX_DATA_NODE_SZ, UBIFS_MAX_INO_NODE_SZ,
1423 		UBIFS_MAX_DENT_NODE_SZ);
1424 	dbg_msg("dead watermark:      %d", c->dead_wm);
1425 	dbg_msg("dark watermark:      %d", c->dark_wm);
1426 	dbg_msg("LEB overhead:        %d", c->leb_overhead);
1427 	x = (long long)c->main_lebs * c->dark_wm;
1428 	dbg_msg("max. dark space:     %lld (%lld KiB, %lld MiB)",
1429 		x, x >> 10, x >> 20);
1430 	dbg_msg("maximum bud bytes:   %lld (%lld KiB, %lld MiB)",
1431 		c->max_bud_bytes, c->max_bud_bytes >> 10,
1432 		c->max_bud_bytes >> 20);
1433 	dbg_msg("BG commit bud bytes: %lld (%lld KiB, %lld MiB)",
1434 		c->bg_bud_bytes, c->bg_bud_bytes >> 10,
1435 		c->bg_bud_bytes >> 20);
1436 	dbg_msg("current bud bytes    %lld (%lld KiB, %lld MiB)",
1437 		c->bud_bytes, c->bud_bytes >> 10, c->bud_bytes >> 20);
1438 	dbg_msg("max. seq. number:    %llu", c->max_sqnum);
1439 	dbg_msg("commit number:       %llu", c->cmt_no);
1440 
1441 	return 0;
1442 
1443 out_infos:
1444 	spin_lock(&ubifs_infos_lock);
1445 	list_del(&c->infos_list);
1446 	spin_unlock(&ubifs_infos_lock);
1447 out_orphans:
1448 	free_orphans(c);
1449 out_journal:
1450 	destroy_journal(c);
1451 out_lpt:
1452 	ubifs_lpt_free(c, 0);
1453 out_master:
1454 	kfree(c->mst_node);
1455 	kfree(c->rcvrd_mst_node);
1456 	if (c->bgt)
1457 		kthread_stop(c->bgt);
1458 out_wbufs:
1459 	free_wbufs(c);
1460 out_cbuf:
1461 	kfree(c->cbuf);
1462 out_free:
1463 	kfree(c->bu.buf);
1464 	vfree(c->ileb_buf);
1465 	vfree(c->sbuf);
1466 	kfree(c->bottom_up_buf);
1467 	ubifs_debugging_exit(c);
1468 	return err;
1469 }
1470 
1471 /**
1472  * ubifs_umount - un-mount UBIFS file-system.
1473  * @c: UBIFS file-system description object
1474  *
1475  * Note, this function is called to free allocated resourced when un-mounting,
1476  * as well as free resources when an error occurred while we were half way
1477  * through mounting (error path cleanup function). So it has to make sure the
1478  * resource was actually allocated before freeing it.
1479  */
1480 static void ubifs_umount(struct ubifs_info *c)
1481 {
1482 	dbg_gen("un-mounting UBI device %d, volume %d", c->vi.ubi_num,
1483 		c->vi.vol_id);
1484 
1485 	dbg_debugfs_exit_fs(c);
1486 	spin_lock(&ubifs_infos_lock);
1487 	list_del(&c->infos_list);
1488 	spin_unlock(&ubifs_infos_lock);
1489 
1490 	if (c->bgt)
1491 		kthread_stop(c->bgt);
1492 
1493 	destroy_journal(c);
1494 	free_wbufs(c);
1495 	free_orphans(c);
1496 	ubifs_lpt_free(c, 0);
1497 
1498 	kfree(c->cbuf);
1499 	kfree(c->rcvrd_mst_node);
1500 	kfree(c->mst_node);
1501 	kfree(c->bu.buf);
1502 	vfree(c->ileb_buf);
1503 	vfree(c->sbuf);
1504 	kfree(c->bottom_up_buf);
1505 	ubifs_debugging_exit(c);
1506 }
1507 
1508 /**
1509  * ubifs_remount_rw - re-mount in read-write mode.
1510  * @c: UBIFS file-system description object
1511  *
1512  * UBIFS avoids allocating many unnecessary resources when mounted in read-only
1513  * mode. This function allocates the needed resources and re-mounts UBIFS in
1514  * read-write mode.
1515  */
1516 static int ubifs_remount_rw(struct ubifs_info *c)
1517 {
1518 	int err, lnum;
1519 
1520 	if (c->rw_incompat) {
1521 		ubifs_err("the file-system is not R/W-compatible");
1522 		ubifs_msg("on-flash format version is w%d/r%d, but software "
1523 			  "only supports up to version w%d/r%d", c->fmt_version,
1524 			  c->ro_compat_version, UBIFS_FORMAT_VERSION,
1525 			  UBIFS_RO_COMPAT_VERSION);
1526 		return -EROFS;
1527 	}
1528 
1529 	mutex_lock(&c->umount_mutex);
1530 	dbg_save_space_info(c);
1531 	c->remounting_rw = 1;
1532 	c->always_chk_crc = 1;
1533 
1534 	err = check_free_space(c);
1535 	if (err)
1536 		goto out;
1537 
1538 	if (c->old_leb_cnt != c->leb_cnt) {
1539 		struct ubifs_sb_node *sup;
1540 
1541 		sup = ubifs_read_sb_node(c);
1542 		if (IS_ERR(sup)) {
1543 			err = PTR_ERR(sup);
1544 			goto out;
1545 		}
1546 		sup->leb_cnt = cpu_to_le32(c->leb_cnt);
1547 		err = ubifs_write_sb_node(c, sup);
1548 		if (err)
1549 			goto out;
1550 	}
1551 
1552 	if (c->need_recovery) {
1553 		ubifs_msg("completing deferred recovery");
1554 		err = ubifs_write_rcvrd_mst_node(c);
1555 		if (err)
1556 			goto out;
1557 		err = ubifs_recover_size(c);
1558 		if (err)
1559 			goto out;
1560 		err = ubifs_clean_lebs(c, c->sbuf);
1561 		if (err)
1562 			goto out;
1563 		err = ubifs_recover_inl_heads(c, c->sbuf);
1564 		if (err)
1565 			goto out;
1566 	} else {
1567 		/* A readonly mount is not allowed to have orphans */
1568 		ubifs_assert(c->tot_orphans == 0);
1569 		err = ubifs_clear_orphans(c);
1570 		if (err)
1571 			goto out;
1572 	}
1573 
1574 	if (!(c->mst_node->flags & cpu_to_le32(UBIFS_MST_DIRTY))) {
1575 		c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
1576 		err = ubifs_write_master(c);
1577 		if (err)
1578 			goto out;
1579 	}
1580 
1581 	c->ileb_buf = vmalloc(c->leb_size);
1582 	if (!c->ileb_buf) {
1583 		err = -ENOMEM;
1584 		goto out;
1585 	}
1586 
1587 	err = ubifs_lpt_init(c, 0, 1);
1588 	if (err)
1589 		goto out;
1590 
1591 	err = alloc_wbufs(c);
1592 	if (err)
1593 		goto out;
1594 
1595 	ubifs_create_buds_lists(c);
1596 
1597 	/* Create background thread */
1598 	c->bgt = kthread_create(ubifs_bg_thread, c, "%s", c->bgt_name);
1599 	if (IS_ERR(c->bgt)) {
1600 		err = PTR_ERR(c->bgt);
1601 		c->bgt = NULL;
1602 		ubifs_err("cannot spawn \"%s\", error %d",
1603 			  c->bgt_name, err);
1604 		goto out;
1605 	}
1606 	wake_up_process(c->bgt);
1607 
1608 	c->orph_buf = vmalloc(c->leb_size);
1609 	if (!c->orph_buf) {
1610 		err = -ENOMEM;
1611 		goto out;
1612 	}
1613 
1614 	/* Check for enough log space */
1615 	lnum = c->lhead_lnum + 1;
1616 	if (lnum >= UBIFS_LOG_LNUM + c->log_lebs)
1617 		lnum = UBIFS_LOG_LNUM;
1618 	if (lnum == c->ltail_lnum) {
1619 		err = ubifs_consolidate_log(c);
1620 		if (err)
1621 			goto out;
1622 	}
1623 
1624 	if (c->need_recovery)
1625 		err = ubifs_rcvry_gc_commit(c);
1626 	else
1627 		err = ubifs_leb_unmap(c, c->gc_lnum);
1628 	if (err)
1629 		goto out;
1630 
1631 	if (c->need_recovery) {
1632 		c->need_recovery = 0;
1633 		ubifs_msg("deferred recovery completed");
1634 	}
1635 
1636 	dbg_gen("re-mounted read-write");
1637 	c->vfs_sb->s_flags &= ~MS_RDONLY;
1638 	c->remounting_rw = 0;
1639 	c->always_chk_crc = 0;
1640 	err = dbg_check_space_info(c);
1641 	mutex_unlock(&c->umount_mutex);
1642 	return err;
1643 
1644 out:
1645 	vfree(c->orph_buf);
1646 	c->orph_buf = NULL;
1647 	if (c->bgt) {
1648 		kthread_stop(c->bgt);
1649 		c->bgt = NULL;
1650 	}
1651 	free_wbufs(c);
1652 	vfree(c->ileb_buf);
1653 	c->ileb_buf = NULL;
1654 	ubifs_lpt_free(c, 1);
1655 	c->remounting_rw = 0;
1656 	c->always_chk_crc = 0;
1657 	mutex_unlock(&c->umount_mutex);
1658 	return err;
1659 }
1660 
1661 /**
1662  * ubifs_remount_ro - re-mount in read-only mode.
1663  * @c: UBIFS file-system description object
1664  *
1665  * We assume VFS has stopped writing. Possibly the background thread could be
1666  * running a commit, however kthread_stop will wait in that case.
1667  */
1668 static void ubifs_remount_ro(struct ubifs_info *c)
1669 {
1670 	int i, err;
1671 
1672 	ubifs_assert(!c->need_recovery);
1673 	ubifs_assert(!(c->vfs_sb->s_flags & MS_RDONLY));
1674 
1675 	mutex_lock(&c->umount_mutex);
1676 	if (c->bgt) {
1677 		kthread_stop(c->bgt);
1678 		c->bgt = NULL;
1679 	}
1680 
1681 	dbg_save_space_info(c);
1682 
1683 	for (i = 0; i < c->jhead_cnt; i++) {
1684 		ubifs_wbuf_sync(&c->jheads[i].wbuf);
1685 		hrtimer_cancel(&c->jheads[i].wbuf.timer);
1686 	}
1687 
1688 	c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_DIRTY);
1689 	c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
1690 	c->mst_node->gc_lnum = cpu_to_le32(c->gc_lnum);
1691 	err = ubifs_write_master(c);
1692 	if (err)
1693 		ubifs_ro_mode(c, err);
1694 
1695 	free_wbufs(c);
1696 	vfree(c->orph_buf);
1697 	c->orph_buf = NULL;
1698 	vfree(c->ileb_buf);
1699 	c->ileb_buf = NULL;
1700 	ubifs_lpt_free(c, 1);
1701 	err = dbg_check_space_info(c);
1702 	if (err)
1703 		ubifs_ro_mode(c, err);
1704 	mutex_unlock(&c->umount_mutex);
1705 }
1706 
1707 static void ubifs_put_super(struct super_block *sb)
1708 {
1709 	int i;
1710 	struct ubifs_info *c = sb->s_fs_info;
1711 
1712 	ubifs_msg("un-mount UBI device %d, volume %d", c->vi.ubi_num,
1713 		  c->vi.vol_id);
1714 
1715 	/*
1716 	 * The following asserts are only valid if there has not been a failure
1717 	 * of the media. For example, there will be dirty inodes if we failed
1718 	 * to write them back because of I/O errors.
1719 	 */
1720 	ubifs_assert(atomic_long_read(&c->dirty_pg_cnt) == 0);
1721 	ubifs_assert(c->budg_idx_growth == 0);
1722 	ubifs_assert(c->budg_dd_growth == 0);
1723 	ubifs_assert(c->budg_data_growth == 0);
1724 
1725 	/*
1726 	 * The 'c->umount_lock' prevents races between UBIFS memory shrinker
1727 	 * and file system un-mount. Namely, it prevents the shrinker from
1728 	 * picking this superblock for shrinking - it will be just skipped if
1729 	 * the mutex is locked.
1730 	 */
1731 	mutex_lock(&c->umount_mutex);
1732 	if (!(c->vfs_sb->s_flags & MS_RDONLY)) {
1733 		/*
1734 		 * First of all kill the background thread to make sure it does
1735 		 * not interfere with un-mounting and freeing resources.
1736 		 */
1737 		if (c->bgt) {
1738 			kthread_stop(c->bgt);
1739 			c->bgt = NULL;
1740 		}
1741 
1742 		/* Synchronize write-buffers */
1743 		if (c->jheads)
1744 			for (i = 0; i < c->jhead_cnt; i++)
1745 				ubifs_wbuf_sync(&c->jheads[i].wbuf);
1746 
1747 		/*
1748 		 * On fatal errors c->ro_media is set to 1, in which case we do
1749 		 * not write the master node.
1750 		 */
1751 		if (!c->ro_media) {
1752 			/*
1753 			 * We are being cleanly unmounted which means the
1754 			 * orphans were killed - indicate this in the master
1755 			 * node. Also save the reserved GC LEB number.
1756 			 */
1757 			int err;
1758 
1759 			c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_DIRTY);
1760 			c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
1761 			c->mst_node->gc_lnum = cpu_to_le32(c->gc_lnum);
1762 			err = ubifs_write_master(c);
1763 			if (err)
1764 				/*
1765 				 * Recovery will attempt to fix the master area
1766 				 * next mount, so we just print a message and
1767 				 * continue to unmount normally.
1768 				 */
1769 				ubifs_err("failed to write master node, "
1770 					  "error %d", err);
1771 		}
1772 	}
1773 
1774 	ubifs_umount(c);
1775 	bdi_destroy(&c->bdi);
1776 	ubi_close_volume(c->ubi);
1777 	mutex_unlock(&c->umount_mutex);
1778 	kfree(c);
1779 }
1780 
1781 static int ubifs_remount_fs(struct super_block *sb, int *flags, char *data)
1782 {
1783 	int err;
1784 	struct ubifs_info *c = sb->s_fs_info;
1785 
1786 	dbg_gen("old flags %#lx, new flags %#x", sb->s_flags, *flags);
1787 
1788 	err = ubifs_parse_options(c, data, 1);
1789 	if (err) {
1790 		ubifs_err("invalid or unknown remount parameter");
1791 		return err;
1792 	}
1793 
1794 	if ((sb->s_flags & MS_RDONLY) && !(*flags & MS_RDONLY)) {
1795 		if (c->ro_media) {
1796 			ubifs_msg("cannot re-mount due to prior errors");
1797 			return -EROFS;
1798 		}
1799 		err = ubifs_remount_rw(c);
1800 		if (err)
1801 			return err;
1802 	} else if (!(sb->s_flags & MS_RDONLY) && (*flags & MS_RDONLY)) {
1803 		if (c->ro_media) {
1804 			ubifs_msg("cannot re-mount due to prior errors");
1805 			return -EROFS;
1806 		}
1807 		ubifs_remount_ro(c);
1808 	}
1809 
1810 	if (c->bulk_read == 1)
1811 		bu_init(c);
1812 	else {
1813 		dbg_gen("disable bulk-read");
1814 		kfree(c->bu.buf);
1815 		c->bu.buf = NULL;
1816 	}
1817 
1818 	ubifs_assert(c->lst.taken_empty_lebs > 0);
1819 	return 0;
1820 }
1821 
1822 const struct super_operations ubifs_super_operations = {
1823 	.alloc_inode   = ubifs_alloc_inode,
1824 	.destroy_inode = ubifs_destroy_inode,
1825 	.put_super     = ubifs_put_super,
1826 	.write_inode   = ubifs_write_inode,
1827 	.delete_inode  = ubifs_delete_inode,
1828 	.statfs        = ubifs_statfs,
1829 	.dirty_inode   = ubifs_dirty_inode,
1830 	.remount_fs    = ubifs_remount_fs,
1831 	.show_options  = ubifs_show_options,
1832 	.sync_fs       = ubifs_sync_fs,
1833 };
1834 
1835 /**
1836  * open_ubi - parse UBI device name string and open the UBI device.
1837  * @name: UBI volume name
1838  * @mode: UBI volume open mode
1839  *
1840  * The primary method of mounting UBIFS is by specifying the UBI volume
1841  * character device node path. However, UBIFS may also be mounted withoug any
1842  * character device node using one of the following methods:
1843  *
1844  * o ubiX_Y    - mount UBI device number X, volume Y;
1845  * o ubiY      - mount UBI device number 0, volume Y;
1846  * o ubiX:NAME - mount UBI device X, volume with name NAME;
1847  * o ubi:NAME  - mount UBI device 0, volume with name NAME.
1848  *
1849  * Alternative '!' separator may be used instead of ':' (because some shells
1850  * like busybox may interpret ':' as an NFS host name separator). This function
1851  * returns UBI volume description object in case of success and a negative
1852  * error code in case of failure.
1853  */
1854 static struct ubi_volume_desc *open_ubi(const char *name, int mode)
1855 {
1856 	struct ubi_volume_desc *ubi;
1857 	int dev, vol;
1858 	char *endptr;
1859 
1860 	/* First, try to open using the device node path method */
1861 	ubi = ubi_open_volume_path(name, mode);
1862 	if (!IS_ERR(ubi))
1863 		return ubi;
1864 
1865 	/* Try the "nodev" method */
1866 	if (name[0] != 'u' || name[1] != 'b' || name[2] != 'i')
1867 		return ERR_PTR(-EINVAL);
1868 
1869 	/* ubi:NAME method */
1870 	if ((name[3] == ':' || name[3] == '!') && name[4] != '\0')
1871 		return ubi_open_volume_nm(0, name + 4, mode);
1872 
1873 	if (!isdigit(name[3]))
1874 		return ERR_PTR(-EINVAL);
1875 
1876 	dev = simple_strtoul(name + 3, &endptr, 0);
1877 
1878 	/* ubiY method */
1879 	if (*endptr == '\0')
1880 		return ubi_open_volume(0, dev, mode);
1881 
1882 	/* ubiX_Y method */
1883 	if (*endptr == '_' && isdigit(endptr[1])) {
1884 		vol = simple_strtoul(endptr + 1, &endptr, 0);
1885 		if (*endptr != '\0')
1886 			return ERR_PTR(-EINVAL);
1887 		return ubi_open_volume(dev, vol, mode);
1888 	}
1889 
1890 	/* ubiX:NAME method */
1891 	if ((*endptr == ':' || *endptr == '!') && endptr[1] != '\0')
1892 		return ubi_open_volume_nm(dev, ++endptr, mode);
1893 
1894 	return ERR_PTR(-EINVAL);
1895 }
1896 
1897 static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
1898 {
1899 	struct ubi_volume_desc *ubi = sb->s_fs_info;
1900 	struct ubifs_info *c;
1901 	struct inode *root;
1902 	int err;
1903 
1904 	c = kzalloc(sizeof(struct ubifs_info), GFP_KERNEL);
1905 	if (!c)
1906 		return -ENOMEM;
1907 
1908 	spin_lock_init(&c->cnt_lock);
1909 	spin_lock_init(&c->cs_lock);
1910 	spin_lock_init(&c->buds_lock);
1911 	spin_lock_init(&c->space_lock);
1912 	spin_lock_init(&c->orphan_lock);
1913 	init_rwsem(&c->commit_sem);
1914 	mutex_init(&c->lp_mutex);
1915 	mutex_init(&c->tnc_mutex);
1916 	mutex_init(&c->log_mutex);
1917 	mutex_init(&c->mst_mutex);
1918 	mutex_init(&c->umount_mutex);
1919 	mutex_init(&c->bu_mutex);
1920 	init_waitqueue_head(&c->cmt_wq);
1921 	c->buds = RB_ROOT;
1922 	c->old_idx = RB_ROOT;
1923 	c->size_tree = RB_ROOT;
1924 	c->orph_tree = RB_ROOT;
1925 	INIT_LIST_HEAD(&c->infos_list);
1926 	INIT_LIST_HEAD(&c->idx_gc);
1927 	INIT_LIST_HEAD(&c->replay_list);
1928 	INIT_LIST_HEAD(&c->replay_buds);
1929 	INIT_LIST_HEAD(&c->uncat_list);
1930 	INIT_LIST_HEAD(&c->empty_list);
1931 	INIT_LIST_HEAD(&c->freeable_list);
1932 	INIT_LIST_HEAD(&c->frdi_idx_list);
1933 	INIT_LIST_HEAD(&c->unclean_leb_list);
1934 	INIT_LIST_HEAD(&c->old_buds);
1935 	INIT_LIST_HEAD(&c->orph_list);
1936 	INIT_LIST_HEAD(&c->orph_new);
1937 
1938 	c->vfs_sb = sb;
1939 	c->highest_inum = UBIFS_FIRST_INO;
1940 	c->lhead_lnum = c->ltail_lnum = UBIFS_LOG_LNUM;
1941 
1942 	ubi_get_volume_info(ubi, &c->vi);
1943 	ubi_get_device_info(c->vi.ubi_num, &c->di);
1944 
1945 	/* Re-open the UBI device in read-write mode */
1946 	c->ubi = ubi_open_volume(c->vi.ubi_num, c->vi.vol_id, UBI_READWRITE);
1947 	if (IS_ERR(c->ubi)) {
1948 		err = PTR_ERR(c->ubi);
1949 		goto out_free;
1950 	}
1951 
1952 	/*
1953 	 * UBIFS provides 'backing_dev_info' in order to disable read-ahead. For
1954 	 * UBIFS, I/O is not deferred, it is done immediately in readpage,
1955 	 * which means the user would have to wait not just for their own I/O
1956 	 * but the read-ahead I/O as well i.e. completely pointless.
1957 	 *
1958 	 * Read-ahead will be disabled because @c->bdi.ra_pages is 0.
1959 	 */
1960 	c->bdi.name = "ubifs",
1961 	c->bdi.capabilities = BDI_CAP_MAP_COPY;
1962 	c->bdi.unplug_io_fn = default_unplug_io_fn;
1963 	err  = bdi_init(&c->bdi);
1964 	if (err)
1965 		goto out_close;
1966 	err = bdi_register(&c->bdi, NULL, "ubifs_%d_%d",
1967 			   c->vi.ubi_num, c->vi.vol_id);
1968 	if (err)
1969 		goto out_bdi;
1970 
1971 	err = ubifs_parse_options(c, data, 0);
1972 	if (err)
1973 		goto out_bdi;
1974 
1975 	sb->s_bdi = &c->bdi;
1976 	sb->s_fs_info = c;
1977 	sb->s_magic = UBIFS_SUPER_MAGIC;
1978 	sb->s_blocksize = UBIFS_BLOCK_SIZE;
1979 	sb->s_blocksize_bits = UBIFS_BLOCK_SHIFT;
1980 	sb->s_maxbytes = c->max_inode_sz = key_max_inode_size(c);
1981 	if (c->max_inode_sz > MAX_LFS_FILESIZE)
1982 		sb->s_maxbytes = c->max_inode_sz = MAX_LFS_FILESIZE;
1983 	sb->s_op = &ubifs_super_operations;
1984 
1985 	mutex_lock(&c->umount_mutex);
1986 	err = mount_ubifs(c);
1987 	if (err) {
1988 		ubifs_assert(err < 0);
1989 		goto out_unlock;
1990 	}
1991 
1992 	/* Read the root inode */
1993 	root = ubifs_iget(sb, UBIFS_ROOT_INO);
1994 	if (IS_ERR(root)) {
1995 		err = PTR_ERR(root);
1996 		goto out_umount;
1997 	}
1998 
1999 	sb->s_root = d_alloc_root(root);
2000 	if (!sb->s_root)
2001 		goto out_iput;
2002 
2003 	mutex_unlock(&c->umount_mutex);
2004 	return 0;
2005 
2006 out_iput:
2007 	iput(root);
2008 out_umount:
2009 	ubifs_umount(c);
2010 out_unlock:
2011 	mutex_unlock(&c->umount_mutex);
2012 out_bdi:
2013 	bdi_destroy(&c->bdi);
2014 out_close:
2015 	ubi_close_volume(c->ubi);
2016 out_free:
2017 	kfree(c);
2018 	return err;
2019 }
2020 
2021 static int sb_test(struct super_block *sb, void *data)
2022 {
2023 	dev_t *dev = data;
2024 	struct ubifs_info *c = sb->s_fs_info;
2025 
2026 	return c->vi.cdev == *dev;
2027 }
2028 
2029 static int ubifs_get_sb(struct file_system_type *fs_type, int flags,
2030 			const char *name, void *data, struct vfsmount *mnt)
2031 {
2032 	struct ubi_volume_desc *ubi;
2033 	struct ubi_volume_info vi;
2034 	struct super_block *sb;
2035 	int err;
2036 
2037 	dbg_gen("name %s, flags %#x", name, flags);
2038 
2039 	/*
2040 	 * Get UBI device number and volume ID. Mount it read-only so far
2041 	 * because this might be a new mount point, and UBI allows only one
2042 	 * read-write user at a time.
2043 	 */
2044 	ubi = open_ubi(name, UBI_READONLY);
2045 	if (IS_ERR(ubi)) {
2046 		ubifs_err("cannot open \"%s\", error %d",
2047 			  name, (int)PTR_ERR(ubi));
2048 		return PTR_ERR(ubi);
2049 	}
2050 	ubi_get_volume_info(ubi, &vi);
2051 
2052 	dbg_gen("opened ubi%d_%d", vi.ubi_num, vi.vol_id);
2053 
2054 	sb = sget(fs_type, &sb_test, &set_anon_super, &vi.cdev);
2055 	if (IS_ERR(sb)) {
2056 		err = PTR_ERR(sb);
2057 		goto out_close;
2058 	}
2059 
2060 	if (sb->s_root) {
2061 		/* A new mount point for already mounted UBIFS */
2062 		dbg_gen("this ubi volume is already mounted");
2063 		if ((flags ^ sb->s_flags) & MS_RDONLY) {
2064 			err = -EBUSY;
2065 			goto out_deact;
2066 		}
2067 	} else {
2068 		sb->s_flags = flags;
2069 		/*
2070 		 * Pass 'ubi' to 'fill_super()' in sb->s_fs_info where it is
2071 		 * replaced by 'c'.
2072 		 */
2073 		sb->s_fs_info = ubi;
2074 		err = ubifs_fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
2075 		if (err)
2076 			goto out_deact;
2077 		/* We do not support atime */
2078 		sb->s_flags |= MS_ACTIVE | MS_NOATIME;
2079 	}
2080 
2081 	/* 'fill_super()' opens ubi again so we must close it here */
2082 	ubi_close_volume(ubi);
2083 
2084 	simple_set_mnt(mnt, sb);
2085 	return 0;
2086 
2087 out_deact:
2088 	deactivate_locked_super(sb);
2089 out_close:
2090 	ubi_close_volume(ubi);
2091 	return err;
2092 }
2093 
2094 static struct file_system_type ubifs_fs_type = {
2095 	.name    = "ubifs",
2096 	.owner   = THIS_MODULE,
2097 	.get_sb  = ubifs_get_sb,
2098 	.kill_sb = kill_anon_super,
2099 };
2100 
2101 /*
2102  * Inode slab cache constructor.
2103  */
2104 static void inode_slab_ctor(void *obj)
2105 {
2106 	struct ubifs_inode *ui = obj;
2107 	inode_init_once(&ui->vfs_inode);
2108 }
2109 
2110 static int __init ubifs_init(void)
2111 {
2112 	int err;
2113 
2114 	BUILD_BUG_ON(sizeof(struct ubifs_ch) != 24);
2115 
2116 	/* Make sure node sizes are 8-byte aligned */
2117 	BUILD_BUG_ON(UBIFS_CH_SZ        & 7);
2118 	BUILD_BUG_ON(UBIFS_INO_NODE_SZ  & 7);
2119 	BUILD_BUG_ON(UBIFS_DENT_NODE_SZ & 7);
2120 	BUILD_BUG_ON(UBIFS_XENT_NODE_SZ & 7);
2121 	BUILD_BUG_ON(UBIFS_DATA_NODE_SZ & 7);
2122 	BUILD_BUG_ON(UBIFS_TRUN_NODE_SZ & 7);
2123 	BUILD_BUG_ON(UBIFS_SB_NODE_SZ   & 7);
2124 	BUILD_BUG_ON(UBIFS_MST_NODE_SZ  & 7);
2125 	BUILD_BUG_ON(UBIFS_REF_NODE_SZ  & 7);
2126 	BUILD_BUG_ON(UBIFS_CS_NODE_SZ   & 7);
2127 	BUILD_BUG_ON(UBIFS_ORPH_NODE_SZ & 7);
2128 
2129 	BUILD_BUG_ON(UBIFS_MAX_DENT_NODE_SZ & 7);
2130 	BUILD_BUG_ON(UBIFS_MAX_XENT_NODE_SZ & 7);
2131 	BUILD_BUG_ON(UBIFS_MAX_DATA_NODE_SZ & 7);
2132 	BUILD_BUG_ON(UBIFS_MAX_INO_NODE_SZ  & 7);
2133 	BUILD_BUG_ON(UBIFS_MAX_NODE_SZ      & 7);
2134 	BUILD_BUG_ON(MIN_WRITE_SZ           & 7);
2135 
2136 	/* Check min. node size */
2137 	BUILD_BUG_ON(UBIFS_INO_NODE_SZ  < MIN_WRITE_SZ);
2138 	BUILD_BUG_ON(UBIFS_DENT_NODE_SZ < MIN_WRITE_SZ);
2139 	BUILD_BUG_ON(UBIFS_XENT_NODE_SZ < MIN_WRITE_SZ);
2140 	BUILD_BUG_ON(UBIFS_TRUN_NODE_SZ < MIN_WRITE_SZ);
2141 
2142 	BUILD_BUG_ON(UBIFS_MAX_DENT_NODE_SZ > UBIFS_MAX_NODE_SZ);
2143 	BUILD_BUG_ON(UBIFS_MAX_XENT_NODE_SZ > UBIFS_MAX_NODE_SZ);
2144 	BUILD_BUG_ON(UBIFS_MAX_DATA_NODE_SZ > UBIFS_MAX_NODE_SZ);
2145 	BUILD_BUG_ON(UBIFS_MAX_INO_NODE_SZ  > UBIFS_MAX_NODE_SZ);
2146 
2147 	/* Defined node sizes */
2148 	BUILD_BUG_ON(UBIFS_SB_NODE_SZ  != 4096);
2149 	BUILD_BUG_ON(UBIFS_MST_NODE_SZ != 512);
2150 	BUILD_BUG_ON(UBIFS_INO_NODE_SZ != 160);
2151 	BUILD_BUG_ON(UBIFS_REF_NODE_SZ != 64);
2152 
2153 	/*
2154 	 * We use 2 bit wide bit-fields to store compression type, which should
2155 	 * be amended if more compressors are added. The bit-fields are:
2156 	 * @compr_type in 'struct ubifs_inode', @default_compr in
2157 	 * 'struct ubifs_info' and @compr_type in 'struct ubifs_mount_opts'.
2158 	 */
2159 	BUILD_BUG_ON(UBIFS_COMPR_TYPES_CNT > 4);
2160 
2161 	/*
2162 	 * We require that PAGE_CACHE_SIZE is greater-than-or-equal-to
2163 	 * UBIFS_BLOCK_SIZE. It is assumed that both are powers of 2.
2164 	 */
2165 	if (PAGE_CACHE_SIZE < UBIFS_BLOCK_SIZE) {
2166 		ubifs_err("VFS page cache size is %u bytes, but UBIFS requires"
2167 			  " at least 4096 bytes",
2168 			  (unsigned int)PAGE_CACHE_SIZE);
2169 		return -EINVAL;
2170 	}
2171 
2172 	err = register_filesystem(&ubifs_fs_type);
2173 	if (err) {
2174 		ubifs_err("cannot register file system, error %d", err);
2175 		return err;
2176 	}
2177 
2178 	err = -ENOMEM;
2179 	ubifs_inode_slab = kmem_cache_create("ubifs_inode_slab",
2180 				sizeof(struct ubifs_inode), 0,
2181 				SLAB_MEM_SPREAD | SLAB_RECLAIM_ACCOUNT,
2182 				&inode_slab_ctor);
2183 	if (!ubifs_inode_slab)
2184 		goto out_reg;
2185 
2186 	register_shrinker(&ubifs_shrinker_info);
2187 
2188 	err = ubifs_compressors_init();
2189 	if (err)
2190 		goto out_shrinker;
2191 
2192 	err = dbg_debugfs_init();
2193 	if (err)
2194 		goto out_compr;
2195 
2196 	return 0;
2197 
2198 out_compr:
2199 	ubifs_compressors_exit();
2200 out_shrinker:
2201 	unregister_shrinker(&ubifs_shrinker_info);
2202 	kmem_cache_destroy(ubifs_inode_slab);
2203 out_reg:
2204 	unregister_filesystem(&ubifs_fs_type);
2205 	return err;
2206 }
2207 /* late_initcall to let compressors initialize first */
2208 late_initcall(ubifs_init);
2209 
2210 static void __exit ubifs_exit(void)
2211 {
2212 	ubifs_assert(list_empty(&ubifs_infos));
2213 	ubifs_assert(atomic_long_read(&ubifs_clean_zn_cnt) == 0);
2214 
2215 	dbg_debugfs_exit();
2216 	ubifs_compressors_exit();
2217 	unregister_shrinker(&ubifs_shrinker_info);
2218 	kmem_cache_destroy(ubifs_inode_slab);
2219 	unregister_filesystem(&ubifs_fs_type);
2220 }
2221 module_exit(ubifs_exit);
2222 
2223 MODULE_LICENSE("GPL");
2224 MODULE_VERSION(__stringify(UBIFS_VERSION));
2225 MODULE_AUTHOR("Artem Bityutskiy, Adrian Hunter");
2226 MODULE_DESCRIPTION("UBIFS - UBI File System");
2227