xref: /openbmc/u-boot/fs/ubifs/lpt.c (revision b0e6ef46)
1 /*
2  * This file is part of UBIFS.
3  *
4  * Copyright (C) 2006-2008 Nokia Corporation.
5  *
6  * SPDX-License-Identifier:	GPL-2.0+
7  *
8  * Authors: Adrian Hunter
9  *          Artem Bityutskiy (Битюцкий Артём)
10  */
11 
12 /*
13  * This file implements the LEB properties tree (LPT) area. The LPT area
14  * contains the LEB properties tree, a table of LPT area eraseblocks (ltab), and
15  * (for the "big" model) a table of saved LEB numbers (lsave). The LPT area sits
16  * between the log and the orphan area.
17  *
18  * The LPT area is like a miniature self-contained file system. It is required
19  * that it never runs out of space, is fast to access and update, and scales
20  * logarithmically. The LEB properties tree is implemented as a wandering tree
21  * much like the TNC, and the LPT area has its own garbage collection.
22  *
23  * The LPT has two slightly different forms called the "small model" and the
24  * "big model". The small model is used when the entire LEB properties table
25  * can be written into a single eraseblock. In that case, garbage collection
26  * consists of just writing the whole table, which therefore makes all other
27  * eraseblocks reusable. In the case of the big model, dirty eraseblocks are
28  * selected for garbage collection, which consists of marking the clean nodes in
29  * that LEB as dirty, and then only the dirty nodes are written out. Also, in
30  * the case of the big model, a table of LEB numbers is saved so that the entire
31  * LPT does not to be scanned looking for empty eraseblocks when UBIFS is first
32  * mounted.
33  */
34 
35 #include "ubifs.h"
36 #ifndef __UBOOT__
37 #include <linux/crc16.h>
38 #include <linux/math64.h>
39 #include <linux/slab.h>
40 #else
41 #include <linux/compat.h>
42 #include <linux/err.h>
43 #include <ubi_uboot.h>
44 #include "crc16.h"
45 #endif
46 
47 /**
48  * do_calc_lpt_geom - calculate sizes for the LPT area.
49  * @c: the UBIFS file-system description object
50  *
51  * Calculate the sizes of LPT bit fields, nodes, and tree, based on the
52  * properties of the flash and whether LPT is "big" (c->big_lpt).
53  */
54 static void do_calc_lpt_geom(struct ubifs_info *c)
55 {
56 	int i, n, bits, per_leb_wastage, max_pnode_cnt;
57 	long long sz, tot_wastage;
58 
59 	n = c->main_lebs + c->max_leb_cnt - c->leb_cnt;
60 	max_pnode_cnt = DIV_ROUND_UP(n, UBIFS_LPT_FANOUT);
61 
62 	c->lpt_hght = 1;
63 	n = UBIFS_LPT_FANOUT;
64 	while (n < max_pnode_cnt) {
65 		c->lpt_hght += 1;
66 		n <<= UBIFS_LPT_FANOUT_SHIFT;
67 	}
68 
69 	c->pnode_cnt = DIV_ROUND_UP(c->main_lebs, UBIFS_LPT_FANOUT);
70 
71 	n = DIV_ROUND_UP(c->pnode_cnt, UBIFS_LPT_FANOUT);
72 	c->nnode_cnt = n;
73 	for (i = 1; i < c->lpt_hght; i++) {
74 		n = DIV_ROUND_UP(n, UBIFS_LPT_FANOUT);
75 		c->nnode_cnt += n;
76 	}
77 
78 	c->space_bits = fls(c->leb_size) - 3;
79 	c->lpt_lnum_bits = fls(c->lpt_lebs);
80 	c->lpt_offs_bits = fls(c->leb_size - 1);
81 	c->lpt_spc_bits = fls(c->leb_size);
82 
83 	n = DIV_ROUND_UP(c->max_leb_cnt, UBIFS_LPT_FANOUT);
84 	c->pcnt_bits = fls(n - 1);
85 
86 	c->lnum_bits = fls(c->max_leb_cnt - 1);
87 
88 	bits = UBIFS_LPT_CRC_BITS + UBIFS_LPT_TYPE_BITS +
89 	       (c->big_lpt ? c->pcnt_bits : 0) +
90 	       (c->space_bits * 2 + 1) * UBIFS_LPT_FANOUT;
91 	c->pnode_sz = (bits + 7) / 8;
92 
93 	bits = UBIFS_LPT_CRC_BITS + UBIFS_LPT_TYPE_BITS +
94 	       (c->big_lpt ? c->pcnt_bits : 0) +
95 	       (c->lpt_lnum_bits + c->lpt_offs_bits) * UBIFS_LPT_FANOUT;
96 	c->nnode_sz = (bits + 7) / 8;
97 
98 	bits = UBIFS_LPT_CRC_BITS + UBIFS_LPT_TYPE_BITS +
99 	       c->lpt_lebs * c->lpt_spc_bits * 2;
100 	c->ltab_sz = (bits + 7) / 8;
101 
102 	bits = UBIFS_LPT_CRC_BITS + UBIFS_LPT_TYPE_BITS +
103 	       c->lnum_bits * c->lsave_cnt;
104 	c->lsave_sz = (bits + 7) / 8;
105 
106 	/* Calculate the minimum LPT size */
107 	c->lpt_sz = (long long)c->pnode_cnt * c->pnode_sz;
108 	c->lpt_sz += (long long)c->nnode_cnt * c->nnode_sz;
109 	c->lpt_sz += c->ltab_sz;
110 	if (c->big_lpt)
111 		c->lpt_sz += c->lsave_sz;
112 
113 	/* Add wastage */
114 	sz = c->lpt_sz;
115 	per_leb_wastage = max_t(int, c->pnode_sz, c->nnode_sz);
116 	sz += per_leb_wastage;
117 	tot_wastage = per_leb_wastage;
118 	while (sz > c->leb_size) {
119 		sz += per_leb_wastage;
120 		sz -= c->leb_size;
121 		tot_wastage += per_leb_wastage;
122 	}
123 	tot_wastage += ALIGN(sz, c->min_io_size) - sz;
124 	c->lpt_sz += tot_wastage;
125 }
126 
127 /**
128  * ubifs_calc_lpt_geom - calculate and check sizes for the LPT area.
129  * @c: the UBIFS file-system description object
130  *
131  * This function returns %0 on success and a negative error code on failure.
132  */
133 int ubifs_calc_lpt_geom(struct ubifs_info *c)
134 {
135 	int lebs_needed;
136 	long long sz;
137 
138 	do_calc_lpt_geom(c);
139 
140 	/* Verify that lpt_lebs is big enough */
141 	sz = c->lpt_sz * 2; /* Must have at least 2 times the size */
142 	lebs_needed = div_u64(sz + c->leb_size - 1, c->leb_size);
143 	if (lebs_needed > c->lpt_lebs) {
144 		ubifs_err("too few LPT LEBs");
145 		return -EINVAL;
146 	}
147 
148 	/* Verify that ltab fits in a single LEB (since ltab is a single node */
149 	if (c->ltab_sz > c->leb_size) {
150 		ubifs_err("LPT ltab too big");
151 		return -EINVAL;
152 	}
153 
154 	c->check_lpt_free = c->big_lpt;
155 	return 0;
156 }
157 
158 /**
159  * calc_dflt_lpt_geom - calculate default LPT geometry.
160  * @c: the UBIFS file-system description object
161  * @main_lebs: number of main area LEBs is passed and returned here
162  * @big_lpt: whether the LPT area is "big" is returned here
163  *
164  * The size of the LPT area depends on parameters that themselves are dependent
165  * on the size of the LPT area. This function, successively recalculates the LPT
166  * area geometry until the parameters and resultant geometry are consistent.
167  *
168  * This function returns %0 on success and a negative error code on failure.
169  */
170 static int calc_dflt_lpt_geom(struct ubifs_info *c, int *main_lebs,
171 			      int *big_lpt)
172 {
173 	int i, lebs_needed;
174 	long long sz;
175 
176 	/* Start by assuming the minimum number of LPT LEBs */
177 	c->lpt_lebs = UBIFS_MIN_LPT_LEBS;
178 	c->main_lebs = *main_lebs - c->lpt_lebs;
179 	if (c->main_lebs <= 0)
180 		return -EINVAL;
181 
182 	/* And assume we will use the small LPT model */
183 	c->big_lpt = 0;
184 
185 	/*
186 	 * Calculate the geometry based on assumptions above and then see if it
187 	 * makes sense
188 	 */
189 	do_calc_lpt_geom(c);
190 
191 	/* Small LPT model must have lpt_sz < leb_size */
192 	if (c->lpt_sz > c->leb_size) {
193 		/* Nope, so try again using big LPT model */
194 		c->big_lpt = 1;
195 		do_calc_lpt_geom(c);
196 	}
197 
198 	/* Now check there are enough LPT LEBs */
199 	for (i = 0; i < 64 ; i++) {
200 		sz = c->lpt_sz * 4; /* Allow 4 times the size */
201 		lebs_needed = div_u64(sz + c->leb_size - 1, c->leb_size);
202 		if (lebs_needed > c->lpt_lebs) {
203 			/* Not enough LPT LEBs so try again with more */
204 			c->lpt_lebs = lebs_needed;
205 			c->main_lebs = *main_lebs - c->lpt_lebs;
206 			if (c->main_lebs <= 0)
207 				return -EINVAL;
208 			do_calc_lpt_geom(c);
209 			continue;
210 		}
211 		if (c->ltab_sz > c->leb_size) {
212 			ubifs_err("LPT ltab too big");
213 			return -EINVAL;
214 		}
215 		*main_lebs = c->main_lebs;
216 		*big_lpt = c->big_lpt;
217 		return 0;
218 	}
219 	return -EINVAL;
220 }
221 
222 /**
223  * pack_bits - pack bit fields end-to-end.
224  * @addr: address at which to pack (passed and next address returned)
225  * @pos: bit position at which to pack (passed and next position returned)
226  * @val: value to pack
227  * @nrbits: number of bits of value to pack (1-32)
228  */
229 static void pack_bits(uint8_t **addr, int *pos, uint32_t val, int nrbits)
230 {
231 	uint8_t *p = *addr;
232 	int b = *pos;
233 
234 	ubifs_assert(nrbits > 0);
235 	ubifs_assert(nrbits <= 32);
236 	ubifs_assert(*pos >= 0);
237 	ubifs_assert(*pos < 8);
238 	ubifs_assert((val >> nrbits) == 0 || nrbits == 32);
239 	if (b) {
240 		*p |= ((uint8_t)val) << b;
241 		nrbits += b;
242 		if (nrbits > 8) {
243 			*++p = (uint8_t)(val >>= (8 - b));
244 			if (nrbits > 16) {
245 				*++p = (uint8_t)(val >>= 8);
246 				if (nrbits > 24) {
247 					*++p = (uint8_t)(val >>= 8);
248 					if (nrbits > 32)
249 						*++p = (uint8_t)(val >>= 8);
250 				}
251 			}
252 		}
253 	} else {
254 		*p = (uint8_t)val;
255 		if (nrbits > 8) {
256 			*++p = (uint8_t)(val >>= 8);
257 			if (nrbits > 16) {
258 				*++p = (uint8_t)(val >>= 8);
259 				if (nrbits > 24)
260 					*++p = (uint8_t)(val >>= 8);
261 			}
262 		}
263 	}
264 	b = nrbits & 7;
265 	if (b == 0)
266 		p++;
267 	*addr = p;
268 	*pos = b;
269 }
270 
271 /**
272  * ubifs_unpack_bits - unpack bit fields.
273  * @addr: address at which to unpack (passed and next address returned)
274  * @pos: bit position at which to unpack (passed and next position returned)
275  * @nrbits: number of bits of value to unpack (1-32)
276  *
277  * This functions returns the value unpacked.
278  */
279 uint32_t ubifs_unpack_bits(uint8_t **addr, int *pos, int nrbits)
280 {
281 	const int k = 32 - nrbits;
282 	uint8_t *p = *addr;
283 	int b = *pos;
284 	uint32_t uninitialized_var(val);
285 	const int bytes = (nrbits + b + 7) >> 3;
286 
287 	ubifs_assert(nrbits > 0);
288 	ubifs_assert(nrbits <= 32);
289 	ubifs_assert(*pos >= 0);
290 	ubifs_assert(*pos < 8);
291 	if (b) {
292 		switch (bytes) {
293 		case 2:
294 			val = p[1];
295 			break;
296 		case 3:
297 			val = p[1] | ((uint32_t)p[2] << 8);
298 			break;
299 		case 4:
300 			val = p[1] | ((uint32_t)p[2] << 8) |
301 				     ((uint32_t)p[3] << 16);
302 			break;
303 		case 5:
304 			val = p[1] | ((uint32_t)p[2] << 8) |
305 				     ((uint32_t)p[3] << 16) |
306 				     ((uint32_t)p[4] << 24);
307 		}
308 		val <<= (8 - b);
309 		val |= *p >> b;
310 		nrbits += b;
311 	} else {
312 		switch (bytes) {
313 		case 1:
314 			val = p[0];
315 			break;
316 		case 2:
317 			val = p[0] | ((uint32_t)p[1] << 8);
318 			break;
319 		case 3:
320 			val = p[0] | ((uint32_t)p[1] << 8) |
321 				     ((uint32_t)p[2] << 16);
322 			break;
323 		case 4:
324 			val = p[0] | ((uint32_t)p[1] << 8) |
325 				     ((uint32_t)p[2] << 16) |
326 				     ((uint32_t)p[3] << 24);
327 			break;
328 		}
329 	}
330 	val <<= k;
331 	val >>= k;
332 	b = nrbits & 7;
333 	p += nrbits >> 3;
334 	*addr = p;
335 	*pos = b;
336 	ubifs_assert((val >> nrbits) == 0 || nrbits - b == 32);
337 	return val;
338 }
339 
340 /**
341  * ubifs_pack_pnode - pack all the bit fields of a pnode.
342  * @c: UBIFS file-system description object
343  * @buf: buffer into which to pack
344  * @pnode: pnode to pack
345  */
346 void ubifs_pack_pnode(struct ubifs_info *c, void *buf,
347 		      struct ubifs_pnode *pnode)
348 {
349 	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
350 	int i, pos = 0;
351 	uint16_t crc;
352 
353 	pack_bits(&addr, &pos, UBIFS_LPT_PNODE, UBIFS_LPT_TYPE_BITS);
354 	if (c->big_lpt)
355 		pack_bits(&addr, &pos, pnode->num, c->pcnt_bits);
356 	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
357 		pack_bits(&addr, &pos, pnode->lprops[i].free >> 3,
358 			  c->space_bits);
359 		pack_bits(&addr, &pos, pnode->lprops[i].dirty >> 3,
360 			  c->space_bits);
361 		if (pnode->lprops[i].flags & LPROPS_INDEX)
362 			pack_bits(&addr, &pos, 1, 1);
363 		else
364 			pack_bits(&addr, &pos, 0, 1);
365 	}
366 	crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
367 		    c->pnode_sz - UBIFS_LPT_CRC_BYTES);
368 	addr = buf;
369 	pos = 0;
370 	pack_bits(&addr, &pos, crc, UBIFS_LPT_CRC_BITS);
371 }
372 
373 /**
374  * ubifs_pack_nnode - pack all the bit fields of a nnode.
375  * @c: UBIFS file-system description object
376  * @buf: buffer into which to pack
377  * @nnode: nnode to pack
378  */
379 void ubifs_pack_nnode(struct ubifs_info *c, void *buf,
380 		      struct ubifs_nnode *nnode)
381 {
382 	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
383 	int i, pos = 0;
384 	uint16_t crc;
385 
386 	pack_bits(&addr, &pos, UBIFS_LPT_NNODE, UBIFS_LPT_TYPE_BITS);
387 	if (c->big_lpt)
388 		pack_bits(&addr, &pos, nnode->num, c->pcnt_bits);
389 	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
390 		int lnum = nnode->nbranch[i].lnum;
391 
392 		if (lnum == 0)
393 			lnum = c->lpt_last + 1;
394 		pack_bits(&addr, &pos, lnum - c->lpt_first, c->lpt_lnum_bits);
395 		pack_bits(&addr, &pos, nnode->nbranch[i].offs,
396 			  c->lpt_offs_bits);
397 	}
398 	crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
399 		    c->nnode_sz - UBIFS_LPT_CRC_BYTES);
400 	addr = buf;
401 	pos = 0;
402 	pack_bits(&addr, &pos, crc, UBIFS_LPT_CRC_BITS);
403 }
404 
405 /**
406  * ubifs_pack_ltab - pack the LPT's own lprops table.
407  * @c: UBIFS file-system description object
408  * @buf: buffer into which to pack
409  * @ltab: LPT's own lprops table to pack
410  */
411 void ubifs_pack_ltab(struct ubifs_info *c, void *buf,
412 		     struct ubifs_lpt_lprops *ltab)
413 {
414 	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
415 	int i, pos = 0;
416 	uint16_t crc;
417 
418 	pack_bits(&addr, &pos, UBIFS_LPT_LTAB, UBIFS_LPT_TYPE_BITS);
419 	for (i = 0; i < c->lpt_lebs; i++) {
420 		pack_bits(&addr, &pos, ltab[i].free, c->lpt_spc_bits);
421 		pack_bits(&addr, &pos, ltab[i].dirty, c->lpt_spc_bits);
422 	}
423 	crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
424 		    c->ltab_sz - UBIFS_LPT_CRC_BYTES);
425 	addr = buf;
426 	pos = 0;
427 	pack_bits(&addr, &pos, crc, UBIFS_LPT_CRC_BITS);
428 }
429 
430 /**
431  * ubifs_pack_lsave - pack the LPT's save table.
432  * @c: UBIFS file-system description object
433  * @buf: buffer into which to pack
434  * @lsave: LPT's save table to pack
435  */
436 void ubifs_pack_lsave(struct ubifs_info *c, void *buf, int *lsave)
437 {
438 	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
439 	int i, pos = 0;
440 	uint16_t crc;
441 
442 	pack_bits(&addr, &pos, UBIFS_LPT_LSAVE, UBIFS_LPT_TYPE_BITS);
443 	for (i = 0; i < c->lsave_cnt; i++)
444 		pack_bits(&addr, &pos, lsave[i], c->lnum_bits);
445 	crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
446 		    c->lsave_sz - UBIFS_LPT_CRC_BYTES);
447 	addr = buf;
448 	pos = 0;
449 	pack_bits(&addr, &pos, crc, UBIFS_LPT_CRC_BITS);
450 }
451 
452 /**
453  * ubifs_add_lpt_dirt - add dirty space to LPT LEB properties.
454  * @c: UBIFS file-system description object
455  * @lnum: LEB number to which to add dirty space
456  * @dirty: amount of dirty space to add
457  */
458 void ubifs_add_lpt_dirt(struct ubifs_info *c, int lnum, int dirty)
459 {
460 	if (!dirty || !lnum)
461 		return;
462 	dbg_lp("LEB %d add %d to %d",
463 	       lnum, dirty, c->ltab[lnum - c->lpt_first].dirty);
464 	ubifs_assert(lnum >= c->lpt_first && lnum <= c->lpt_last);
465 	c->ltab[lnum - c->lpt_first].dirty += dirty;
466 }
467 
468 /**
469  * set_ltab - set LPT LEB properties.
470  * @c: UBIFS file-system description object
471  * @lnum: LEB number
472  * @free: amount of free space
473  * @dirty: amount of dirty space
474  */
475 static void set_ltab(struct ubifs_info *c, int lnum, int free, int dirty)
476 {
477 	dbg_lp("LEB %d free %d dirty %d to %d %d",
478 	       lnum, c->ltab[lnum - c->lpt_first].free,
479 	       c->ltab[lnum - c->lpt_first].dirty, free, dirty);
480 	ubifs_assert(lnum >= c->lpt_first && lnum <= c->lpt_last);
481 	c->ltab[lnum - c->lpt_first].free = free;
482 	c->ltab[lnum - c->lpt_first].dirty = dirty;
483 }
484 
485 /**
486  * ubifs_add_nnode_dirt - add dirty space to LPT LEB properties.
487  * @c: UBIFS file-system description object
488  * @nnode: nnode for which to add dirt
489  */
490 void ubifs_add_nnode_dirt(struct ubifs_info *c, struct ubifs_nnode *nnode)
491 {
492 	struct ubifs_nnode *np = nnode->parent;
493 
494 	if (np)
495 		ubifs_add_lpt_dirt(c, np->nbranch[nnode->iip].lnum,
496 				   c->nnode_sz);
497 	else {
498 		ubifs_add_lpt_dirt(c, c->lpt_lnum, c->nnode_sz);
499 		if (!(c->lpt_drty_flgs & LTAB_DIRTY)) {
500 			c->lpt_drty_flgs |= LTAB_DIRTY;
501 			ubifs_add_lpt_dirt(c, c->ltab_lnum, c->ltab_sz);
502 		}
503 	}
504 }
505 
506 /**
507  * add_pnode_dirt - add dirty space to LPT LEB properties.
508  * @c: UBIFS file-system description object
509  * @pnode: pnode for which to add dirt
510  */
511 static void add_pnode_dirt(struct ubifs_info *c, struct ubifs_pnode *pnode)
512 {
513 	ubifs_add_lpt_dirt(c, pnode->parent->nbranch[pnode->iip].lnum,
514 			   c->pnode_sz);
515 }
516 
517 /**
518  * calc_nnode_num - calculate nnode number.
519  * @row: the row in the tree (root is zero)
520  * @col: the column in the row (leftmost is zero)
521  *
522  * The nnode number is a number that uniquely identifies a nnode and can be used
523  * easily to traverse the tree from the root to that nnode.
524  *
525  * This function calculates and returns the nnode number for the nnode at @row
526  * and @col.
527  */
528 static int calc_nnode_num(int row, int col)
529 {
530 	int num, bits;
531 
532 	num = 1;
533 	while (row--) {
534 		bits = (col & (UBIFS_LPT_FANOUT - 1));
535 		col >>= UBIFS_LPT_FANOUT_SHIFT;
536 		num <<= UBIFS_LPT_FANOUT_SHIFT;
537 		num |= bits;
538 	}
539 	return num;
540 }
541 
542 /**
543  * calc_nnode_num_from_parent - calculate nnode number.
544  * @c: UBIFS file-system description object
545  * @parent: parent nnode
546  * @iip: index in parent
547  *
548  * The nnode number is a number that uniquely identifies a nnode and can be used
549  * easily to traverse the tree from the root to that nnode.
550  *
551  * This function calculates and returns the nnode number based on the parent's
552  * nnode number and the index in parent.
553  */
554 static int calc_nnode_num_from_parent(const struct ubifs_info *c,
555 				      struct ubifs_nnode *parent, int iip)
556 {
557 	int num, shft;
558 
559 	if (!parent)
560 		return 1;
561 	shft = (c->lpt_hght - parent->level) * UBIFS_LPT_FANOUT_SHIFT;
562 	num = parent->num ^ (1 << shft);
563 	num |= (UBIFS_LPT_FANOUT + iip) << shft;
564 	return num;
565 }
566 
567 /**
568  * calc_pnode_num_from_parent - calculate pnode number.
569  * @c: UBIFS file-system description object
570  * @parent: parent nnode
571  * @iip: index in parent
572  *
573  * The pnode number is a number that uniquely identifies a pnode and can be used
574  * easily to traverse the tree from the root to that pnode.
575  *
576  * This function calculates and returns the pnode number based on the parent's
577  * nnode number and the index in parent.
578  */
579 static int calc_pnode_num_from_parent(const struct ubifs_info *c,
580 				      struct ubifs_nnode *parent, int iip)
581 {
582 	int i, n = c->lpt_hght - 1, pnum = parent->num, num = 0;
583 
584 	for (i = 0; i < n; i++) {
585 		num <<= UBIFS_LPT_FANOUT_SHIFT;
586 		num |= pnum & (UBIFS_LPT_FANOUT - 1);
587 		pnum >>= UBIFS_LPT_FANOUT_SHIFT;
588 	}
589 	num <<= UBIFS_LPT_FANOUT_SHIFT;
590 	num |= iip;
591 	return num;
592 }
593 
594 /**
595  * ubifs_create_dflt_lpt - create default LPT.
596  * @c: UBIFS file-system description object
597  * @main_lebs: number of main area LEBs is passed and returned here
598  * @lpt_first: LEB number of first LPT LEB
599  * @lpt_lebs: number of LEBs for LPT is passed and returned here
600  * @big_lpt: use big LPT model is passed and returned here
601  *
602  * This function returns %0 on success and a negative error code on failure.
603  */
604 int ubifs_create_dflt_lpt(struct ubifs_info *c, int *main_lebs, int lpt_first,
605 			  int *lpt_lebs, int *big_lpt)
606 {
607 	int lnum, err = 0, node_sz, iopos, i, j, cnt, len, alen, row;
608 	int blnum, boffs, bsz, bcnt;
609 	struct ubifs_pnode *pnode = NULL;
610 	struct ubifs_nnode *nnode = NULL;
611 	void *buf = NULL, *p;
612 	struct ubifs_lpt_lprops *ltab = NULL;
613 	int *lsave = NULL;
614 
615 	err = calc_dflt_lpt_geom(c, main_lebs, big_lpt);
616 	if (err)
617 		return err;
618 	*lpt_lebs = c->lpt_lebs;
619 
620 	/* Needed by 'ubifs_pack_nnode()' and 'set_ltab()' */
621 	c->lpt_first = lpt_first;
622 	/* Needed by 'set_ltab()' */
623 	c->lpt_last = lpt_first + c->lpt_lebs - 1;
624 	/* Needed by 'ubifs_pack_lsave()' */
625 	c->main_first = c->leb_cnt - *main_lebs;
626 
627 	lsave = kmalloc(sizeof(int) * c->lsave_cnt, GFP_KERNEL);
628 	pnode = kzalloc(sizeof(struct ubifs_pnode), GFP_KERNEL);
629 	nnode = kzalloc(sizeof(struct ubifs_nnode), GFP_KERNEL);
630 	buf = vmalloc(c->leb_size);
631 	ltab = vmalloc(sizeof(struct ubifs_lpt_lprops) * c->lpt_lebs);
632 	if (!pnode || !nnode || !buf || !ltab || !lsave) {
633 		err = -ENOMEM;
634 		goto out;
635 	}
636 
637 	ubifs_assert(!c->ltab);
638 	c->ltab = ltab; /* Needed by set_ltab */
639 
640 	/* Initialize LPT's own lprops */
641 	for (i = 0; i < c->lpt_lebs; i++) {
642 		ltab[i].free = c->leb_size;
643 		ltab[i].dirty = 0;
644 		ltab[i].tgc = 0;
645 		ltab[i].cmt = 0;
646 	}
647 
648 	lnum = lpt_first;
649 	p = buf;
650 	/* Number of leaf nodes (pnodes) */
651 	cnt = c->pnode_cnt;
652 
653 	/*
654 	 * The first pnode contains the LEB properties for the LEBs that contain
655 	 * the root inode node and the root index node of the index tree.
656 	 */
657 	node_sz = ALIGN(ubifs_idx_node_sz(c, 1), 8);
658 	iopos = ALIGN(node_sz, c->min_io_size);
659 	pnode->lprops[0].free = c->leb_size - iopos;
660 	pnode->lprops[0].dirty = iopos - node_sz;
661 	pnode->lprops[0].flags = LPROPS_INDEX;
662 
663 	node_sz = UBIFS_INO_NODE_SZ;
664 	iopos = ALIGN(node_sz, c->min_io_size);
665 	pnode->lprops[1].free = c->leb_size - iopos;
666 	pnode->lprops[1].dirty = iopos - node_sz;
667 
668 	for (i = 2; i < UBIFS_LPT_FANOUT; i++)
669 		pnode->lprops[i].free = c->leb_size;
670 
671 	/* Add first pnode */
672 	ubifs_pack_pnode(c, p, pnode);
673 	p += c->pnode_sz;
674 	len = c->pnode_sz;
675 	pnode->num += 1;
676 
677 	/* Reset pnode values for remaining pnodes */
678 	pnode->lprops[0].free = c->leb_size;
679 	pnode->lprops[0].dirty = 0;
680 	pnode->lprops[0].flags = 0;
681 
682 	pnode->lprops[1].free = c->leb_size;
683 	pnode->lprops[1].dirty = 0;
684 
685 	/*
686 	 * To calculate the internal node branches, we keep information about
687 	 * the level below.
688 	 */
689 	blnum = lnum; /* LEB number of level below */
690 	boffs = 0; /* Offset of level below */
691 	bcnt = cnt; /* Number of nodes in level below */
692 	bsz = c->pnode_sz; /* Size of nodes in level below */
693 
694 	/* Add all remaining pnodes */
695 	for (i = 1; i < cnt; i++) {
696 		if (len + c->pnode_sz > c->leb_size) {
697 			alen = ALIGN(len, c->min_io_size);
698 			set_ltab(c, lnum, c->leb_size - alen, alen - len);
699 			memset(p, 0xff, alen - len);
700 			err = ubifs_leb_change(c, lnum++, buf, alen);
701 			if (err)
702 				goto out;
703 			p = buf;
704 			len = 0;
705 		}
706 		ubifs_pack_pnode(c, p, pnode);
707 		p += c->pnode_sz;
708 		len += c->pnode_sz;
709 		/*
710 		 * pnodes are simply numbered left to right starting at zero,
711 		 * which means the pnode number can be used easily to traverse
712 		 * down the tree to the corresponding pnode.
713 		 */
714 		pnode->num += 1;
715 	}
716 
717 	row = 0;
718 	for (i = UBIFS_LPT_FANOUT; cnt > i; i <<= UBIFS_LPT_FANOUT_SHIFT)
719 		row += 1;
720 	/* Add all nnodes, one level at a time */
721 	while (1) {
722 		/* Number of internal nodes (nnodes) at next level */
723 		cnt = DIV_ROUND_UP(cnt, UBIFS_LPT_FANOUT);
724 		for (i = 0; i < cnt; i++) {
725 			if (len + c->nnode_sz > c->leb_size) {
726 				alen = ALIGN(len, c->min_io_size);
727 				set_ltab(c, lnum, c->leb_size - alen,
728 					    alen - len);
729 				memset(p, 0xff, alen - len);
730 				err = ubifs_leb_change(c, lnum++, buf, alen);
731 				if (err)
732 					goto out;
733 				p = buf;
734 				len = 0;
735 			}
736 			/* Only 1 nnode at this level, so it is the root */
737 			if (cnt == 1) {
738 				c->lpt_lnum = lnum;
739 				c->lpt_offs = len;
740 			}
741 			/* Set branches to the level below */
742 			for (j = 0; j < UBIFS_LPT_FANOUT; j++) {
743 				if (bcnt) {
744 					if (boffs + bsz > c->leb_size) {
745 						blnum += 1;
746 						boffs = 0;
747 					}
748 					nnode->nbranch[j].lnum = blnum;
749 					nnode->nbranch[j].offs = boffs;
750 					boffs += bsz;
751 					bcnt--;
752 				} else {
753 					nnode->nbranch[j].lnum = 0;
754 					nnode->nbranch[j].offs = 0;
755 				}
756 			}
757 			nnode->num = calc_nnode_num(row, i);
758 			ubifs_pack_nnode(c, p, nnode);
759 			p += c->nnode_sz;
760 			len += c->nnode_sz;
761 		}
762 		/* Only 1 nnode at this level, so it is the root */
763 		if (cnt == 1)
764 			break;
765 		/* Update the information about the level below */
766 		bcnt = cnt;
767 		bsz = c->nnode_sz;
768 		row -= 1;
769 	}
770 
771 	if (*big_lpt) {
772 		/* Need to add LPT's save table */
773 		if (len + c->lsave_sz > c->leb_size) {
774 			alen = ALIGN(len, c->min_io_size);
775 			set_ltab(c, lnum, c->leb_size - alen, alen - len);
776 			memset(p, 0xff, alen - len);
777 			err = ubifs_leb_change(c, lnum++, buf, alen);
778 			if (err)
779 				goto out;
780 			p = buf;
781 			len = 0;
782 		}
783 
784 		c->lsave_lnum = lnum;
785 		c->lsave_offs = len;
786 
787 		for (i = 0; i < c->lsave_cnt && i < *main_lebs; i++)
788 			lsave[i] = c->main_first + i;
789 		for (; i < c->lsave_cnt; i++)
790 			lsave[i] = c->main_first;
791 
792 		ubifs_pack_lsave(c, p, lsave);
793 		p += c->lsave_sz;
794 		len += c->lsave_sz;
795 	}
796 
797 	/* Need to add LPT's own LEB properties table */
798 	if (len + c->ltab_sz > c->leb_size) {
799 		alen = ALIGN(len, c->min_io_size);
800 		set_ltab(c, lnum, c->leb_size - alen, alen - len);
801 		memset(p, 0xff, alen - len);
802 		err = ubifs_leb_change(c, lnum++, buf, alen);
803 		if (err)
804 			goto out;
805 		p = buf;
806 		len = 0;
807 	}
808 
809 	c->ltab_lnum = lnum;
810 	c->ltab_offs = len;
811 
812 	/* Update ltab before packing it */
813 	len += c->ltab_sz;
814 	alen = ALIGN(len, c->min_io_size);
815 	set_ltab(c, lnum, c->leb_size - alen, alen - len);
816 
817 	ubifs_pack_ltab(c, p, ltab);
818 	p += c->ltab_sz;
819 
820 	/* Write remaining buffer */
821 	memset(p, 0xff, alen - len);
822 	err = ubifs_leb_change(c, lnum, buf, alen);
823 	if (err)
824 		goto out;
825 
826 	c->nhead_lnum = lnum;
827 	c->nhead_offs = ALIGN(len, c->min_io_size);
828 
829 	dbg_lp("space_bits %d", c->space_bits);
830 	dbg_lp("lpt_lnum_bits %d", c->lpt_lnum_bits);
831 	dbg_lp("lpt_offs_bits %d", c->lpt_offs_bits);
832 	dbg_lp("lpt_spc_bits %d", c->lpt_spc_bits);
833 	dbg_lp("pcnt_bits %d", c->pcnt_bits);
834 	dbg_lp("lnum_bits %d", c->lnum_bits);
835 	dbg_lp("pnode_sz %d", c->pnode_sz);
836 	dbg_lp("nnode_sz %d", c->nnode_sz);
837 	dbg_lp("ltab_sz %d", c->ltab_sz);
838 	dbg_lp("lsave_sz %d", c->lsave_sz);
839 	dbg_lp("lsave_cnt %d", c->lsave_cnt);
840 	dbg_lp("lpt_hght %d", c->lpt_hght);
841 	dbg_lp("big_lpt %d", c->big_lpt);
842 	dbg_lp("LPT root is at %d:%d", c->lpt_lnum, c->lpt_offs);
843 	dbg_lp("LPT head is at %d:%d", c->nhead_lnum, c->nhead_offs);
844 	dbg_lp("LPT ltab is at %d:%d", c->ltab_lnum, c->ltab_offs);
845 	if (c->big_lpt)
846 		dbg_lp("LPT lsave is at %d:%d", c->lsave_lnum, c->lsave_offs);
847 out:
848 	c->ltab = NULL;
849 	kfree(lsave);
850 	vfree(ltab);
851 	vfree(buf);
852 	kfree(nnode);
853 	kfree(pnode);
854 	return err;
855 }
856 
857 /**
858  * update_cats - add LEB properties of a pnode to LEB category lists and heaps.
859  * @c: UBIFS file-system description object
860  * @pnode: pnode
861  *
862  * When a pnode is loaded into memory, the LEB properties it contains are added,
863  * by this function, to the LEB category lists and heaps.
864  */
865 static void update_cats(struct ubifs_info *c, struct ubifs_pnode *pnode)
866 {
867 	int i;
868 
869 	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
870 		int cat = pnode->lprops[i].flags & LPROPS_CAT_MASK;
871 		int lnum = pnode->lprops[i].lnum;
872 
873 		if (!lnum)
874 			return;
875 		ubifs_add_to_cat(c, &pnode->lprops[i], cat);
876 	}
877 }
878 
879 /**
880  * replace_cats - add LEB properties of a pnode to LEB category lists and heaps.
881  * @c: UBIFS file-system description object
882  * @old_pnode: pnode copied
883  * @new_pnode: pnode copy
884  *
885  * During commit it is sometimes necessary to copy a pnode
886  * (see dirty_cow_pnode).  When that happens, references in
887  * category lists and heaps must be replaced.  This function does that.
888  */
889 static void replace_cats(struct ubifs_info *c, struct ubifs_pnode *old_pnode,
890 			 struct ubifs_pnode *new_pnode)
891 {
892 	int i;
893 
894 	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
895 		if (!new_pnode->lprops[i].lnum)
896 			return;
897 		ubifs_replace_cat(c, &old_pnode->lprops[i],
898 				  &new_pnode->lprops[i]);
899 	}
900 }
901 
902 /**
903  * check_lpt_crc - check LPT node crc is correct.
904  * @c: UBIFS file-system description object
905  * @buf: buffer containing node
906  * @len: length of node
907  *
908  * This function returns %0 on success and a negative error code on failure.
909  */
910 static int check_lpt_crc(void *buf, int len)
911 {
912 	int pos = 0;
913 	uint8_t *addr = buf;
914 	uint16_t crc, calc_crc;
915 
916 	crc = ubifs_unpack_bits(&addr, &pos, UBIFS_LPT_CRC_BITS);
917 	calc_crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
918 			 len - UBIFS_LPT_CRC_BYTES);
919 	if (crc != calc_crc) {
920 		ubifs_err("invalid crc in LPT node: crc %hx calc %hx", crc,
921 			  calc_crc);
922 		dump_stack();
923 		return -EINVAL;
924 	}
925 	return 0;
926 }
927 
928 /**
929  * check_lpt_type - check LPT node type is correct.
930  * @c: UBIFS file-system description object
931  * @addr: address of type bit field is passed and returned updated here
932  * @pos: position of type bit field is passed and returned updated here
933  * @type: expected type
934  *
935  * This function returns %0 on success and a negative error code on failure.
936  */
937 static int check_lpt_type(uint8_t **addr, int *pos, int type)
938 {
939 	int node_type;
940 
941 	node_type = ubifs_unpack_bits(addr, pos, UBIFS_LPT_TYPE_BITS);
942 	if (node_type != type) {
943 		ubifs_err("invalid type (%d) in LPT node type %d", node_type,
944 			  type);
945 		dump_stack();
946 		return -EINVAL;
947 	}
948 	return 0;
949 }
950 
951 /**
952  * unpack_pnode - unpack a pnode.
953  * @c: UBIFS file-system description object
954  * @buf: buffer containing packed pnode to unpack
955  * @pnode: pnode structure to fill
956  *
957  * This function returns %0 on success and a negative error code on failure.
958  */
959 static int unpack_pnode(const struct ubifs_info *c, void *buf,
960 			struct ubifs_pnode *pnode)
961 {
962 	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
963 	int i, pos = 0, err;
964 
965 	err = check_lpt_type(&addr, &pos, UBIFS_LPT_PNODE);
966 	if (err)
967 		return err;
968 	if (c->big_lpt)
969 		pnode->num = ubifs_unpack_bits(&addr, &pos, c->pcnt_bits);
970 	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
971 		struct ubifs_lprops * const lprops = &pnode->lprops[i];
972 
973 		lprops->free = ubifs_unpack_bits(&addr, &pos, c->space_bits);
974 		lprops->free <<= 3;
975 		lprops->dirty = ubifs_unpack_bits(&addr, &pos, c->space_bits);
976 		lprops->dirty <<= 3;
977 
978 		if (ubifs_unpack_bits(&addr, &pos, 1))
979 			lprops->flags = LPROPS_INDEX;
980 		else
981 			lprops->flags = 0;
982 		lprops->flags |= ubifs_categorize_lprops(c, lprops);
983 	}
984 	err = check_lpt_crc(buf, c->pnode_sz);
985 	return err;
986 }
987 
988 /**
989  * ubifs_unpack_nnode - unpack a nnode.
990  * @c: UBIFS file-system description object
991  * @buf: buffer containing packed nnode to unpack
992  * @nnode: nnode structure to fill
993  *
994  * This function returns %0 on success and a negative error code on failure.
995  */
996 int ubifs_unpack_nnode(const struct ubifs_info *c, void *buf,
997 		       struct ubifs_nnode *nnode)
998 {
999 	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
1000 	int i, pos = 0, err;
1001 
1002 	err = check_lpt_type(&addr, &pos, UBIFS_LPT_NNODE);
1003 	if (err)
1004 		return err;
1005 	if (c->big_lpt)
1006 		nnode->num = ubifs_unpack_bits(&addr, &pos, c->pcnt_bits);
1007 	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1008 		int lnum;
1009 
1010 		lnum = ubifs_unpack_bits(&addr, &pos, c->lpt_lnum_bits) +
1011 		       c->lpt_first;
1012 		if (lnum == c->lpt_last + 1)
1013 			lnum = 0;
1014 		nnode->nbranch[i].lnum = lnum;
1015 		nnode->nbranch[i].offs = ubifs_unpack_bits(&addr, &pos,
1016 						     c->lpt_offs_bits);
1017 	}
1018 	err = check_lpt_crc(buf, c->nnode_sz);
1019 	return err;
1020 }
1021 
1022 /**
1023  * unpack_ltab - unpack the LPT's own lprops table.
1024  * @c: UBIFS file-system description object
1025  * @buf: buffer from which to unpack
1026  *
1027  * This function returns %0 on success and a negative error code on failure.
1028  */
1029 static int unpack_ltab(const struct ubifs_info *c, void *buf)
1030 {
1031 	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
1032 	int i, pos = 0, err;
1033 
1034 	err = check_lpt_type(&addr, &pos, UBIFS_LPT_LTAB);
1035 	if (err)
1036 		return err;
1037 	for (i = 0; i < c->lpt_lebs; i++) {
1038 		int free = ubifs_unpack_bits(&addr, &pos, c->lpt_spc_bits);
1039 		int dirty = ubifs_unpack_bits(&addr, &pos, c->lpt_spc_bits);
1040 
1041 		if (free < 0 || free > c->leb_size || dirty < 0 ||
1042 		    dirty > c->leb_size || free + dirty > c->leb_size)
1043 			return -EINVAL;
1044 
1045 		c->ltab[i].free = free;
1046 		c->ltab[i].dirty = dirty;
1047 		c->ltab[i].tgc = 0;
1048 		c->ltab[i].cmt = 0;
1049 	}
1050 	err = check_lpt_crc(buf, c->ltab_sz);
1051 	return err;
1052 }
1053 
1054 #ifndef __UBOOT__
1055 /**
1056  * unpack_lsave - unpack the LPT's save table.
1057  * @c: UBIFS file-system description object
1058  * @buf: buffer from which to unpack
1059  *
1060  * This function returns %0 on success and a negative error code on failure.
1061  */
1062 static int unpack_lsave(const struct ubifs_info *c, void *buf)
1063 {
1064 	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
1065 	int i, pos = 0, err;
1066 
1067 	err = check_lpt_type(&addr, &pos, UBIFS_LPT_LSAVE);
1068 	if (err)
1069 		return err;
1070 	for (i = 0; i < c->lsave_cnt; i++) {
1071 		int lnum = ubifs_unpack_bits(&addr, &pos, c->lnum_bits);
1072 
1073 		if (lnum < c->main_first || lnum >= c->leb_cnt)
1074 			return -EINVAL;
1075 		c->lsave[i] = lnum;
1076 	}
1077 	err = check_lpt_crc(buf, c->lsave_sz);
1078 	return err;
1079 }
1080 #endif
1081 
1082 /**
1083  * validate_nnode - validate a nnode.
1084  * @c: UBIFS file-system description object
1085  * @nnode: nnode to validate
1086  * @parent: parent nnode (or NULL for the root nnode)
1087  * @iip: index in parent
1088  *
1089  * This function returns %0 on success and a negative error code on failure.
1090  */
1091 static int validate_nnode(const struct ubifs_info *c, struct ubifs_nnode *nnode,
1092 			  struct ubifs_nnode *parent, int iip)
1093 {
1094 	int i, lvl, max_offs;
1095 
1096 	if (c->big_lpt) {
1097 		int num = calc_nnode_num_from_parent(c, parent, iip);
1098 
1099 		if (nnode->num != num)
1100 			return -EINVAL;
1101 	}
1102 	lvl = parent ? parent->level - 1 : c->lpt_hght;
1103 	if (lvl < 1)
1104 		return -EINVAL;
1105 	if (lvl == 1)
1106 		max_offs = c->leb_size - c->pnode_sz;
1107 	else
1108 		max_offs = c->leb_size - c->nnode_sz;
1109 	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1110 		int lnum = nnode->nbranch[i].lnum;
1111 		int offs = nnode->nbranch[i].offs;
1112 
1113 		if (lnum == 0) {
1114 			if (offs != 0)
1115 				return -EINVAL;
1116 			continue;
1117 		}
1118 		if (lnum < c->lpt_first || lnum > c->lpt_last)
1119 			return -EINVAL;
1120 		if (offs < 0 || offs > max_offs)
1121 			return -EINVAL;
1122 	}
1123 	return 0;
1124 }
1125 
1126 /**
1127  * validate_pnode - validate a pnode.
1128  * @c: UBIFS file-system description object
1129  * @pnode: pnode to validate
1130  * @parent: parent nnode
1131  * @iip: index in parent
1132  *
1133  * This function returns %0 on success and a negative error code on failure.
1134  */
1135 static int validate_pnode(const struct ubifs_info *c, struct ubifs_pnode *pnode,
1136 			  struct ubifs_nnode *parent, int iip)
1137 {
1138 	int i;
1139 
1140 	if (c->big_lpt) {
1141 		int num = calc_pnode_num_from_parent(c, parent, iip);
1142 
1143 		if (pnode->num != num)
1144 			return -EINVAL;
1145 	}
1146 	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1147 		int free = pnode->lprops[i].free;
1148 		int dirty = pnode->lprops[i].dirty;
1149 
1150 		if (free < 0 || free > c->leb_size || free % c->min_io_size ||
1151 		    (free & 7))
1152 			return -EINVAL;
1153 		if (dirty < 0 || dirty > c->leb_size || (dirty & 7))
1154 			return -EINVAL;
1155 		if (dirty + free > c->leb_size)
1156 			return -EINVAL;
1157 	}
1158 	return 0;
1159 }
1160 
1161 /**
1162  * set_pnode_lnum - set LEB numbers on a pnode.
1163  * @c: UBIFS file-system description object
1164  * @pnode: pnode to update
1165  *
1166  * This function calculates the LEB numbers for the LEB properties it contains
1167  * based on the pnode number.
1168  */
1169 static void set_pnode_lnum(const struct ubifs_info *c,
1170 			   struct ubifs_pnode *pnode)
1171 {
1172 	int i, lnum;
1173 
1174 	lnum = (pnode->num << UBIFS_LPT_FANOUT_SHIFT) + c->main_first;
1175 	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1176 		if (lnum >= c->leb_cnt)
1177 			return;
1178 		pnode->lprops[i].lnum = lnum++;
1179 	}
1180 }
1181 
1182 /**
1183  * ubifs_read_nnode - read a nnode from flash and link it to the tree in memory.
1184  * @c: UBIFS file-system description object
1185  * @parent: parent nnode (or NULL for the root)
1186  * @iip: index in parent
1187  *
1188  * This function returns %0 on success and a negative error code on failure.
1189  */
1190 int ubifs_read_nnode(struct ubifs_info *c, struct ubifs_nnode *parent, int iip)
1191 {
1192 	struct ubifs_nbranch *branch = NULL;
1193 	struct ubifs_nnode *nnode = NULL;
1194 	void *buf = c->lpt_nod_buf;
1195 	int err, lnum, offs;
1196 
1197 	if (parent) {
1198 		branch = &parent->nbranch[iip];
1199 		lnum = branch->lnum;
1200 		offs = branch->offs;
1201 	} else {
1202 		lnum = c->lpt_lnum;
1203 		offs = c->lpt_offs;
1204 	}
1205 	nnode = kzalloc(sizeof(struct ubifs_nnode), GFP_NOFS);
1206 	if (!nnode) {
1207 		err = -ENOMEM;
1208 		goto out;
1209 	}
1210 	if (lnum == 0) {
1211 		/*
1212 		 * This nnode was not written which just means that the LEB
1213 		 * properties in the subtree below it describe empty LEBs. We
1214 		 * make the nnode as though we had read it, which in fact means
1215 		 * doing almost nothing.
1216 		 */
1217 		if (c->big_lpt)
1218 			nnode->num = calc_nnode_num_from_parent(c, parent, iip);
1219 	} else {
1220 		err = ubifs_leb_read(c, lnum, buf, offs, c->nnode_sz, 1);
1221 		if (err)
1222 			goto out;
1223 		err = ubifs_unpack_nnode(c, buf, nnode);
1224 		if (err)
1225 			goto out;
1226 	}
1227 	err = validate_nnode(c, nnode, parent, iip);
1228 	if (err)
1229 		goto out;
1230 	if (!c->big_lpt)
1231 		nnode->num = calc_nnode_num_from_parent(c, parent, iip);
1232 	if (parent) {
1233 		branch->nnode = nnode;
1234 		nnode->level = parent->level - 1;
1235 	} else {
1236 		c->nroot = nnode;
1237 		nnode->level = c->lpt_hght;
1238 	}
1239 	nnode->parent = parent;
1240 	nnode->iip = iip;
1241 	return 0;
1242 
1243 out:
1244 	ubifs_err("error %d reading nnode at %d:%d", err, lnum, offs);
1245 	dump_stack();
1246 	kfree(nnode);
1247 	return err;
1248 }
1249 
1250 /**
1251  * read_pnode - read a pnode from flash and link it to the tree in memory.
1252  * @c: UBIFS file-system description object
1253  * @parent: parent nnode
1254  * @iip: index in parent
1255  *
1256  * This function returns %0 on success and a negative error code on failure.
1257  */
1258 static int read_pnode(struct ubifs_info *c, struct ubifs_nnode *parent, int iip)
1259 {
1260 	struct ubifs_nbranch *branch;
1261 	struct ubifs_pnode *pnode = NULL;
1262 	void *buf = c->lpt_nod_buf;
1263 	int err, lnum, offs;
1264 
1265 	branch = &parent->nbranch[iip];
1266 	lnum = branch->lnum;
1267 	offs = branch->offs;
1268 	pnode = kzalloc(sizeof(struct ubifs_pnode), GFP_NOFS);
1269 	if (!pnode)
1270 		return -ENOMEM;
1271 
1272 	if (lnum == 0) {
1273 		/*
1274 		 * This pnode was not written which just means that the LEB
1275 		 * properties in it describe empty LEBs. We make the pnode as
1276 		 * though we had read it.
1277 		 */
1278 		int i;
1279 
1280 		if (c->big_lpt)
1281 			pnode->num = calc_pnode_num_from_parent(c, parent, iip);
1282 		for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1283 			struct ubifs_lprops * const lprops = &pnode->lprops[i];
1284 
1285 			lprops->free = c->leb_size;
1286 			lprops->flags = ubifs_categorize_lprops(c, lprops);
1287 		}
1288 	} else {
1289 		err = ubifs_leb_read(c, lnum, buf, offs, c->pnode_sz, 1);
1290 		if (err)
1291 			goto out;
1292 		err = unpack_pnode(c, buf, pnode);
1293 		if (err)
1294 			goto out;
1295 	}
1296 	err = validate_pnode(c, pnode, parent, iip);
1297 	if (err)
1298 		goto out;
1299 	if (!c->big_lpt)
1300 		pnode->num = calc_pnode_num_from_parent(c, parent, iip);
1301 	branch->pnode = pnode;
1302 	pnode->parent = parent;
1303 	pnode->iip = iip;
1304 	set_pnode_lnum(c, pnode);
1305 	c->pnodes_have += 1;
1306 	return 0;
1307 
1308 out:
1309 	ubifs_err("error %d reading pnode at %d:%d", err, lnum, offs);
1310 	ubifs_dump_pnode(c, pnode, parent, iip);
1311 	dump_stack();
1312 	ubifs_err("calc num: %d", calc_pnode_num_from_parent(c, parent, iip));
1313 	kfree(pnode);
1314 	return err;
1315 }
1316 
1317 /**
1318  * read_ltab - read LPT's own lprops table.
1319  * @c: UBIFS file-system description object
1320  *
1321  * This function returns %0 on success and a negative error code on failure.
1322  */
1323 static int read_ltab(struct ubifs_info *c)
1324 {
1325 	int err;
1326 	void *buf;
1327 
1328 	buf = vmalloc(c->ltab_sz);
1329 	if (!buf)
1330 		return -ENOMEM;
1331 	err = ubifs_leb_read(c, c->ltab_lnum, buf, c->ltab_offs, c->ltab_sz, 1);
1332 	if (err)
1333 		goto out;
1334 	err = unpack_ltab(c, buf);
1335 out:
1336 	vfree(buf);
1337 	return err;
1338 }
1339 
1340 #ifndef __UBOOT__
1341 /**
1342  * read_lsave - read LPT's save table.
1343  * @c: UBIFS file-system description object
1344  *
1345  * This function returns %0 on success and a negative error code on failure.
1346  */
1347 static int read_lsave(struct ubifs_info *c)
1348 {
1349 	int err, i;
1350 	void *buf;
1351 
1352 	buf = vmalloc(c->lsave_sz);
1353 	if (!buf)
1354 		return -ENOMEM;
1355 	err = ubifs_leb_read(c, c->lsave_lnum, buf, c->lsave_offs,
1356 			     c->lsave_sz, 1);
1357 	if (err)
1358 		goto out;
1359 	err = unpack_lsave(c, buf);
1360 	if (err)
1361 		goto out;
1362 	for (i = 0; i < c->lsave_cnt; i++) {
1363 		int lnum = c->lsave[i];
1364 		struct ubifs_lprops *lprops;
1365 
1366 		/*
1367 		 * Due to automatic resizing, the values in the lsave table
1368 		 * could be beyond the volume size - just ignore them.
1369 		 */
1370 		if (lnum >= c->leb_cnt)
1371 			continue;
1372 		lprops = ubifs_lpt_lookup(c, lnum);
1373 		if (IS_ERR(lprops)) {
1374 			err = PTR_ERR(lprops);
1375 			goto out;
1376 		}
1377 	}
1378 out:
1379 	vfree(buf);
1380 	return err;
1381 }
1382 #endif
1383 
1384 /**
1385  * ubifs_get_nnode - get a nnode.
1386  * @c: UBIFS file-system description object
1387  * @parent: parent nnode (or NULL for the root)
1388  * @iip: index in parent
1389  *
1390  * This function returns a pointer to the nnode on success or a negative error
1391  * code on failure.
1392  */
1393 struct ubifs_nnode *ubifs_get_nnode(struct ubifs_info *c,
1394 				    struct ubifs_nnode *parent, int iip)
1395 {
1396 	struct ubifs_nbranch *branch;
1397 	struct ubifs_nnode *nnode;
1398 	int err;
1399 
1400 	branch = &parent->nbranch[iip];
1401 	nnode = branch->nnode;
1402 	if (nnode)
1403 		return nnode;
1404 	err = ubifs_read_nnode(c, parent, iip);
1405 	if (err)
1406 		return ERR_PTR(err);
1407 	return branch->nnode;
1408 }
1409 
1410 /**
1411  * ubifs_get_pnode - get a pnode.
1412  * @c: UBIFS file-system description object
1413  * @parent: parent nnode
1414  * @iip: index in parent
1415  *
1416  * This function returns a pointer to the pnode on success or a negative error
1417  * code on failure.
1418  */
1419 struct ubifs_pnode *ubifs_get_pnode(struct ubifs_info *c,
1420 				    struct ubifs_nnode *parent, int iip)
1421 {
1422 	struct ubifs_nbranch *branch;
1423 	struct ubifs_pnode *pnode;
1424 	int err;
1425 
1426 	branch = &parent->nbranch[iip];
1427 	pnode = branch->pnode;
1428 	if (pnode)
1429 		return pnode;
1430 	err = read_pnode(c, parent, iip);
1431 	if (err)
1432 		return ERR_PTR(err);
1433 	update_cats(c, branch->pnode);
1434 	return branch->pnode;
1435 }
1436 
1437 /**
1438  * ubifs_lpt_lookup - lookup LEB properties in the LPT.
1439  * @c: UBIFS file-system description object
1440  * @lnum: LEB number to lookup
1441  *
1442  * This function returns a pointer to the LEB properties on success or a
1443  * negative error code on failure.
1444  */
1445 struct ubifs_lprops *ubifs_lpt_lookup(struct ubifs_info *c, int lnum)
1446 {
1447 	int err, i, h, iip, shft;
1448 	struct ubifs_nnode *nnode;
1449 	struct ubifs_pnode *pnode;
1450 
1451 	if (!c->nroot) {
1452 		err = ubifs_read_nnode(c, NULL, 0);
1453 		if (err)
1454 			return ERR_PTR(err);
1455 	}
1456 	nnode = c->nroot;
1457 	i = lnum - c->main_first;
1458 	shft = c->lpt_hght * UBIFS_LPT_FANOUT_SHIFT;
1459 	for (h = 1; h < c->lpt_hght; h++) {
1460 		iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
1461 		shft -= UBIFS_LPT_FANOUT_SHIFT;
1462 		nnode = ubifs_get_nnode(c, nnode, iip);
1463 		if (IS_ERR(nnode))
1464 			return ERR_CAST(nnode);
1465 	}
1466 	iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
1467 	shft -= UBIFS_LPT_FANOUT_SHIFT;
1468 	pnode = ubifs_get_pnode(c, nnode, iip);
1469 	if (IS_ERR(pnode))
1470 		return ERR_CAST(pnode);
1471 	iip = (i & (UBIFS_LPT_FANOUT - 1));
1472 	dbg_lp("LEB %d, free %d, dirty %d, flags %d", lnum,
1473 	       pnode->lprops[iip].free, pnode->lprops[iip].dirty,
1474 	       pnode->lprops[iip].flags);
1475 	return &pnode->lprops[iip];
1476 }
1477 
1478 /**
1479  * dirty_cow_nnode - ensure a nnode is not being committed.
1480  * @c: UBIFS file-system description object
1481  * @nnode: nnode to check
1482  *
1483  * Returns dirtied nnode on success or negative error code on failure.
1484  */
1485 static struct ubifs_nnode *dirty_cow_nnode(struct ubifs_info *c,
1486 					   struct ubifs_nnode *nnode)
1487 {
1488 	struct ubifs_nnode *n;
1489 	int i;
1490 
1491 	if (!test_bit(COW_CNODE, &nnode->flags)) {
1492 		/* nnode is not being committed */
1493 		if (!test_and_set_bit(DIRTY_CNODE, &nnode->flags)) {
1494 			c->dirty_nn_cnt += 1;
1495 			ubifs_add_nnode_dirt(c, nnode);
1496 		}
1497 		return nnode;
1498 	}
1499 
1500 	/* nnode is being committed, so copy it */
1501 	n = kmalloc(sizeof(struct ubifs_nnode), GFP_NOFS);
1502 	if (unlikely(!n))
1503 		return ERR_PTR(-ENOMEM);
1504 
1505 	memcpy(n, nnode, sizeof(struct ubifs_nnode));
1506 	n->cnext = NULL;
1507 	__set_bit(DIRTY_CNODE, &n->flags);
1508 	__clear_bit(COW_CNODE, &n->flags);
1509 
1510 	/* The children now have new parent */
1511 	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1512 		struct ubifs_nbranch *branch = &n->nbranch[i];
1513 
1514 		if (branch->cnode)
1515 			branch->cnode->parent = n;
1516 	}
1517 
1518 	ubifs_assert(!test_bit(OBSOLETE_CNODE, &nnode->flags));
1519 	__set_bit(OBSOLETE_CNODE, &nnode->flags);
1520 
1521 	c->dirty_nn_cnt += 1;
1522 	ubifs_add_nnode_dirt(c, nnode);
1523 	if (nnode->parent)
1524 		nnode->parent->nbranch[n->iip].nnode = n;
1525 	else
1526 		c->nroot = n;
1527 	return n;
1528 }
1529 
1530 /**
1531  * dirty_cow_pnode - ensure a pnode is not being committed.
1532  * @c: UBIFS file-system description object
1533  * @pnode: pnode to check
1534  *
1535  * Returns dirtied pnode on success or negative error code on failure.
1536  */
1537 static struct ubifs_pnode *dirty_cow_pnode(struct ubifs_info *c,
1538 					   struct ubifs_pnode *pnode)
1539 {
1540 	struct ubifs_pnode *p;
1541 
1542 	if (!test_bit(COW_CNODE, &pnode->flags)) {
1543 		/* pnode is not being committed */
1544 		if (!test_and_set_bit(DIRTY_CNODE, &pnode->flags)) {
1545 			c->dirty_pn_cnt += 1;
1546 			add_pnode_dirt(c, pnode);
1547 		}
1548 		return pnode;
1549 	}
1550 
1551 	/* pnode is being committed, so copy it */
1552 	p = kmalloc(sizeof(struct ubifs_pnode), GFP_NOFS);
1553 	if (unlikely(!p))
1554 		return ERR_PTR(-ENOMEM);
1555 
1556 	memcpy(p, pnode, sizeof(struct ubifs_pnode));
1557 	p->cnext = NULL;
1558 	__set_bit(DIRTY_CNODE, &p->flags);
1559 	__clear_bit(COW_CNODE, &p->flags);
1560 	replace_cats(c, pnode, p);
1561 
1562 	ubifs_assert(!test_bit(OBSOLETE_CNODE, &pnode->flags));
1563 	__set_bit(OBSOLETE_CNODE, &pnode->flags);
1564 
1565 	c->dirty_pn_cnt += 1;
1566 	add_pnode_dirt(c, pnode);
1567 	pnode->parent->nbranch[p->iip].pnode = p;
1568 	return p;
1569 }
1570 
1571 /**
1572  * ubifs_lpt_lookup_dirty - lookup LEB properties in the LPT.
1573  * @c: UBIFS file-system description object
1574  * @lnum: LEB number to lookup
1575  *
1576  * This function returns a pointer to the LEB properties on success or a
1577  * negative error code on failure.
1578  */
1579 struct ubifs_lprops *ubifs_lpt_lookup_dirty(struct ubifs_info *c, int lnum)
1580 {
1581 	int err, i, h, iip, shft;
1582 	struct ubifs_nnode *nnode;
1583 	struct ubifs_pnode *pnode;
1584 
1585 	if (!c->nroot) {
1586 		err = ubifs_read_nnode(c, NULL, 0);
1587 		if (err)
1588 			return ERR_PTR(err);
1589 	}
1590 	nnode = c->nroot;
1591 	nnode = dirty_cow_nnode(c, nnode);
1592 	if (IS_ERR(nnode))
1593 		return ERR_CAST(nnode);
1594 	i = lnum - c->main_first;
1595 	shft = c->lpt_hght * UBIFS_LPT_FANOUT_SHIFT;
1596 	for (h = 1; h < c->lpt_hght; h++) {
1597 		iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
1598 		shft -= UBIFS_LPT_FANOUT_SHIFT;
1599 		nnode = ubifs_get_nnode(c, nnode, iip);
1600 		if (IS_ERR(nnode))
1601 			return ERR_CAST(nnode);
1602 		nnode = dirty_cow_nnode(c, nnode);
1603 		if (IS_ERR(nnode))
1604 			return ERR_CAST(nnode);
1605 	}
1606 	iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
1607 	shft -= UBIFS_LPT_FANOUT_SHIFT;
1608 	pnode = ubifs_get_pnode(c, nnode, iip);
1609 	if (IS_ERR(pnode))
1610 		return ERR_CAST(pnode);
1611 	pnode = dirty_cow_pnode(c, pnode);
1612 	if (IS_ERR(pnode))
1613 		return ERR_CAST(pnode);
1614 	iip = (i & (UBIFS_LPT_FANOUT - 1));
1615 	dbg_lp("LEB %d, free %d, dirty %d, flags %d", lnum,
1616 	       pnode->lprops[iip].free, pnode->lprops[iip].dirty,
1617 	       pnode->lprops[iip].flags);
1618 	ubifs_assert(test_bit(DIRTY_CNODE, &pnode->flags));
1619 	return &pnode->lprops[iip];
1620 }
1621 
1622 /**
1623  * lpt_init_rd - initialize the LPT for reading.
1624  * @c: UBIFS file-system description object
1625  *
1626  * This function returns %0 on success and a negative error code on failure.
1627  */
1628 static int lpt_init_rd(struct ubifs_info *c)
1629 {
1630 	int err, i;
1631 
1632 	c->ltab = vmalloc(sizeof(struct ubifs_lpt_lprops) * c->lpt_lebs);
1633 	if (!c->ltab)
1634 		return -ENOMEM;
1635 
1636 	i = max_t(int, c->nnode_sz, c->pnode_sz);
1637 	c->lpt_nod_buf = kmalloc(i, GFP_KERNEL);
1638 	if (!c->lpt_nod_buf)
1639 		return -ENOMEM;
1640 
1641 	for (i = 0; i < LPROPS_HEAP_CNT; i++) {
1642 		c->lpt_heap[i].arr = kmalloc(sizeof(void *) * LPT_HEAP_SZ,
1643 					     GFP_KERNEL);
1644 		if (!c->lpt_heap[i].arr)
1645 			return -ENOMEM;
1646 		c->lpt_heap[i].cnt = 0;
1647 		c->lpt_heap[i].max_cnt = LPT_HEAP_SZ;
1648 	}
1649 
1650 	c->dirty_idx.arr = kmalloc(sizeof(void *) * LPT_HEAP_SZ, GFP_KERNEL);
1651 	if (!c->dirty_idx.arr)
1652 		return -ENOMEM;
1653 	c->dirty_idx.cnt = 0;
1654 	c->dirty_idx.max_cnt = LPT_HEAP_SZ;
1655 
1656 	err = read_ltab(c);
1657 	if (err)
1658 		return err;
1659 
1660 	dbg_lp("space_bits %d", c->space_bits);
1661 	dbg_lp("lpt_lnum_bits %d", c->lpt_lnum_bits);
1662 	dbg_lp("lpt_offs_bits %d", c->lpt_offs_bits);
1663 	dbg_lp("lpt_spc_bits %d", c->lpt_spc_bits);
1664 	dbg_lp("pcnt_bits %d", c->pcnt_bits);
1665 	dbg_lp("lnum_bits %d", c->lnum_bits);
1666 	dbg_lp("pnode_sz %d", c->pnode_sz);
1667 	dbg_lp("nnode_sz %d", c->nnode_sz);
1668 	dbg_lp("ltab_sz %d", c->ltab_sz);
1669 	dbg_lp("lsave_sz %d", c->lsave_sz);
1670 	dbg_lp("lsave_cnt %d", c->lsave_cnt);
1671 	dbg_lp("lpt_hght %d", c->lpt_hght);
1672 	dbg_lp("big_lpt %d", c->big_lpt);
1673 	dbg_lp("LPT root is at %d:%d", c->lpt_lnum, c->lpt_offs);
1674 	dbg_lp("LPT head is at %d:%d", c->nhead_lnum, c->nhead_offs);
1675 	dbg_lp("LPT ltab is at %d:%d", c->ltab_lnum, c->ltab_offs);
1676 	if (c->big_lpt)
1677 		dbg_lp("LPT lsave is at %d:%d", c->lsave_lnum, c->lsave_offs);
1678 
1679 	return 0;
1680 }
1681 
1682 #ifndef __UBOOT__
1683 /**
1684  * lpt_init_wr - initialize the LPT for writing.
1685  * @c: UBIFS file-system description object
1686  *
1687  * 'lpt_init_rd()' must have been called already.
1688  *
1689  * This function returns %0 on success and a negative error code on failure.
1690  */
1691 static int lpt_init_wr(struct ubifs_info *c)
1692 {
1693 	int err, i;
1694 
1695 	c->ltab_cmt = vmalloc(sizeof(struct ubifs_lpt_lprops) * c->lpt_lebs);
1696 	if (!c->ltab_cmt)
1697 		return -ENOMEM;
1698 
1699 	c->lpt_buf = vmalloc(c->leb_size);
1700 	if (!c->lpt_buf)
1701 		return -ENOMEM;
1702 
1703 	if (c->big_lpt) {
1704 		c->lsave = kmalloc(sizeof(int) * c->lsave_cnt, GFP_NOFS);
1705 		if (!c->lsave)
1706 			return -ENOMEM;
1707 		err = read_lsave(c);
1708 		if (err)
1709 			return err;
1710 	}
1711 
1712 	for (i = 0; i < c->lpt_lebs; i++)
1713 		if (c->ltab[i].free == c->leb_size) {
1714 			err = ubifs_leb_unmap(c, i + c->lpt_first);
1715 			if (err)
1716 				return err;
1717 		}
1718 
1719 	return 0;
1720 }
1721 #endif
1722 
1723 /**
1724  * ubifs_lpt_init - initialize the LPT.
1725  * @c: UBIFS file-system description object
1726  * @rd: whether to initialize lpt for reading
1727  * @wr: whether to initialize lpt for writing
1728  *
1729  * For mounting 'rw', @rd and @wr are both true. For mounting 'ro', @rd is true
1730  * and @wr is false. For mounting from 'ro' to 'rw', @rd is false and @wr is
1731  * true.
1732  *
1733  * This function returns %0 on success and a negative error code on failure.
1734  */
1735 int ubifs_lpt_init(struct ubifs_info *c, int rd, int wr)
1736 {
1737 	int err;
1738 
1739 	if (rd) {
1740 		err = lpt_init_rd(c);
1741 		if (err)
1742 			goto out_err;
1743 	}
1744 
1745 #ifndef __UBOOT__
1746 	if (wr) {
1747 		err = lpt_init_wr(c);
1748 		if (err)
1749 			goto out_err;
1750 	}
1751 #endif
1752 
1753 	return 0;
1754 
1755 out_err:
1756 #ifndef __UBOOT__
1757 	if (wr)
1758 		ubifs_lpt_free(c, 1);
1759 #endif
1760 	if (rd)
1761 		ubifs_lpt_free(c, 0);
1762 	return err;
1763 }
1764 
1765 /**
1766  * struct lpt_scan_node - somewhere to put nodes while we scan LPT.
1767  * @nnode: where to keep a nnode
1768  * @pnode: where to keep a pnode
1769  * @cnode: where to keep a cnode
1770  * @in_tree: is the node in the tree in memory
1771  * @ptr.nnode: pointer to the nnode (if it is an nnode) which may be here or in
1772  * the tree
1773  * @ptr.pnode: ditto for pnode
1774  * @ptr.cnode: ditto for cnode
1775  */
1776 struct lpt_scan_node {
1777 	union {
1778 		struct ubifs_nnode nnode;
1779 		struct ubifs_pnode pnode;
1780 		struct ubifs_cnode cnode;
1781 	};
1782 	int in_tree;
1783 	union {
1784 		struct ubifs_nnode *nnode;
1785 		struct ubifs_pnode *pnode;
1786 		struct ubifs_cnode *cnode;
1787 	} ptr;
1788 };
1789 
1790 /**
1791  * scan_get_nnode - for the scan, get a nnode from either the tree or flash.
1792  * @c: the UBIFS file-system description object
1793  * @path: where to put the nnode
1794  * @parent: parent of the nnode
1795  * @iip: index in parent of the nnode
1796  *
1797  * This function returns a pointer to the nnode on success or a negative error
1798  * code on failure.
1799  */
1800 static struct ubifs_nnode *scan_get_nnode(struct ubifs_info *c,
1801 					  struct lpt_scan_node *path,
1802 					  struct ubifs_nnode *parent, int iip)
1803 {
1804 	struct ubifs_nbranch *branch;
1805 	struct ubifs_nnode *nnode;
1806 	void *buf = c->lpt_nod_buf;
1807 	int err;
1808 
1809 	branch = &parent->nbranch[iip];
1810 	nnode = branch->nnode;
1811 	if (nnode) {
1812 		path->in_tree = 1;
1813 		path->ptr.nnode = nnode;
1814 		return nnode;
1815 	}
1816 	nnode = &path->nnode;
1817 	path->in_tree = 0;
1818 	path->ptr.nnode = nnode;
1819 	memset(nnode, 0, sizeof(struct ubifs_nnode));
1820 	if (branch->lnum == 0) {
1821 		/*
1822 		 * This nnode was not written which just means that the LEB
1823 		 * properties in the subtree below it describe empty LEBs. We
1824 		 * make the nnode as though we had read it, which in fact means
1825 		 * doing almost nothing.
1826 		 */
1827 		if (c->big_lpt)
1828 			nnode->num = calc_nnode_num_from_parent(c, parent, iip);
1829 	} else {
1830 		err = ubifs_leb_read(c, branch->lnum, buf, branch->offs,
1831 				     c->nnode_sz, 1);
1832 		if (err)
1833 			return ERR_PTR(err);
1834 		err = ubifs_unpack_nnode(c, buf, nnode);
1835 		if (err)
1836 			return ERR_PTR(err);
1837 	}
1838 	err = validate_nnode(c, nnode, parent, iip);
1839 	if (err)
1840 		return ERR_PTR(err);
1841 	if (!c->big_lpt)
1842 		nnode->num = calc_nnode_num_from_parent(c, parent, iip);
1843 	nnode->level = parent->level - 1;
1844 	nnode->parent = parent;
1845 	nnode->iip = iip;
1846 	return nnode;
1847 }
1848 
1849 /**
1850  * scan_get_pnode - for the scan, get a pnode from either the tree or flash.
1851  * @c: the UBIFS file-system description object
1852  * @path: where to put the pnode
1853  * @parent: parent of the pnode
1854  * @iip: index in parent of the pnode
1855  *
1856  * This function returns a pointer to the pnode on success or a negative error
1857  * code on failure.
1858  */
1859 static struct ubifs_pnode *scan_get_pnode(struct ubifs_info *c,
1860 					  struct lpt_scan_node *path,
1861 					  struct ubifs_nnode *parent, int iip)
1862 {
1863 	struct ubifs_nbranch *branch;
1864 	struct ubifs_pnode *pnode;
1865 	void *buf = c->lpt_nod_buf;
1866 	int err;
1867 
1868 	branch = &parent->nbranch[iip];
1869 	pnode = branch->pnode;
1870 	if (pnode) {
1871 		path->in_tree = 1;
1872 		path->ptr.pnode = pnode;
1873 		return pnode;
1874 	}
1875 	pnode = &path->pnode;
1876 	path->in_tree = 0;
1877 	path->ptr.pnode = pnode;
1878 	memset(pnode, 0, sizeof(struct ubifs_pnode));
1879 	if (branch->lnum == 0) {
1880 		/*
1881 		 * This pnode was not written which just means that the LEB
1882 		 * properties in it describe empty LEBs. We make the pnode as
1883 		 * though we had read it.
1884 		 */
1885 		int i;
1886 
1887 		if (c->big_lpt)
1888 			pnode->num = calc_pnode_num_from_parent(c, parent, iip);
1889 		for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1890 			struct ubifs_lprops * const lprops = &pnode->lprops[i];
1891 
1892 			lprops->free = c->leb_size;
1893 			lprops->flags = ubifs_categorize_lprops(c, lprops);
1894 		}
1895 	} else {
1896 		ubifs_assert(branch->lnum >= c->lpt_first &&
1897 			     branch->lnum <= c->lpt_last);
1898 		ubifs_assert(branch->offs >= 0 && branch->offs < c->leb_size);
1899 		err = ubifs_leb_read(c, branch->lnum, buf, branch->offs,
1900 				     c->pnode_sz, 1);
1901 		if (err)
1902 			return ERR_PTR(err);
1903 		err = unpack_pnode(c, buf, pnode);
1904 		if (err)
1905 			return ERR_PTR(err);
1906 	}
1907 	err = validate_pnode(c, pnode, parent, iip);
1908 	if (err)
1909 		return ERR_PTR(err);
1910 	if (!c->big_lpt)
1911 		pnode->num = calc_pnode_num_from_parent(c, parent, iip);
1912 	pnode->parent = parent;
1913 	pnode->iip = iip;
1914 	set_pnode_lnum(c, pnode);
1915 	return pnode;
1916 }
1917 
1918 /**
1919  * ubifs_lpt_scan_nolock - scan the LPT.
1920  * @c: the UBIFS file-system description object
1921  * @start_lnum: LEB number from which to start scanning
1922  * @end_lnum: LEB number at which to stop scanning
1923  * @scan_cb: callback function called for each lprops
1924  * @data: data to be passed to the callback function
1925  *
1926  * This function returns %0 on success and a negative error code on failure.
1927  */
1928 int ubifs_lpt_scan_nolock(struct ubifs_info *c, int start_lnum, int end_lnum,
1929 			  ubifs_lpt_scan_callback scan_cb, void *data)
1930 {
1931 	int err = 0, i, h, iip, shft;
1932 	struct ubifs_nnode *nnode;
1933 	struct ubifs_pnode *pnode;
1934 	struct lpt_scan_node *path;
1935 
1936 	if (start_lnum == -1) {
1937 		start_lnum = end_lnum + 1;
1938 		if (start_lnum >= c->leb_cnt)
1939 			start_lnum = c->main_first;
1940 	}
1941 
1942 	ubifs_assert(start_lnum >= c->main_first && start_lnum < c->leb_cnt);
1943 	ubifs_assert(end_lnum >= c->main_first && end_lnum < c->leb_cnt);
1944 
1945 	if (!c->nroot) {
1946 		err = ubifs_read_nnode(c, NULL, 0);
1947 		if (err)
1948 			return err;
1949 	}
1950 
1951 	path = kmalloc(sizeof(struct lpt_scan_node) * (c->lpt_hght + 1),
1952 		       GFP_NOFS);
1953 	if (!path)
1954 		return -ENOMEM;
1955 
1956 	path[0].ptr.nnode = c->nroot;
1957 	path[0].in_tree = 1;
1958 again:
1959 	/* Descend to the pnode containing start_lnum */
1960 	nnode = c->nroot;
1961 	i = start_lnum - c->main_first;
1962 	shft = c->lpt_hght * UBIFS_LPT_FANOUT_SHIFT;
1963 	for (h = 1; h < c->lpt_hght; h++) {
1964 		iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
1965 		shft -= UBIFS_LPT_FANOUT_SHIFT;
1966 		nnode = scan_get_nnode(c, path + h, nnode, iip);
1967 		if (IS_ERR(nnode)) {
1968 			err = PTR_ERR(nnode);
1969 			goto out;
1970 		}
1971 	}
1972 	iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
1973 	shft -= UBIFS_LPT_FANOUT_SHIFT;
1974 	pnode = scan_get_pnode(c, path + h, nnode, iip);
1975 	if (IS_ERR(pnode)) {
1976 		err = PTR_ERR(pnode);
1977 		goto out;
1978 	}
1979 	iip = (i & (UBIFS_LPT_FANOUT - 1));
1980 
1981 	/* Loop for each lprops */
1982 	while (1) {
1983 		struct ubifs_lprops *lprops = &pnode->lprops[iip];
1984 		int ret, lnum = lprops->lnum;
1985 
1986 		ret = scan_cb(c, lprops, path[h].in_tree, data);
1987 		if (ret < 0) {
1988 			err = ret;
1989 			goto out;
1990 		}
1991 		if (ret & LPT_SCAN_ADD) {
1992 			/* Add all the nodes in path to the tree in memory */
1993 			for (h = 1; h < c->lpt_hght; h++) {
1994 				const size_t sz = sizeof(struct ubifs_nnode);
1995 				struct ubifs_nnode *parent;
1996 
1997 				if (path[h].in_tree)
1998 					continue;
1999 				nnode = kmemdup(&path[h].nnode, sz, GFP_NOFS);
2000 				if (!nnode) {
2001 					err = -ENOMEM;
2002 					goto out;
2003 				}
2004 				parent = nnode->parent;
2005 				parent->nbranch[nnode->iip].nnode = nnode;
2006 				path[h].ptr.nnode = nnode;
2007 				path[h].in_tree = 1;
2008 				path[h + 1].cnode.parent = nnode;
2009 			}
2010 			if (path[h].in_tree)
2011 				ubifs_ensure_cat(c, lprops);
2012 			else {
2013 				const size_t sz = sizeof(struct ubifs_pnode);
2014 				struct ubifs_nnode *parent;
2015 
2016 				pnode = kmemdup(&path[h].pnode, sz, GFP_NOFS);
2017 				if (!pnode) {
2018 					err = -ENOMEM;
2019 					goto out;
2020 				}
2021 				parent = pnode->parent;
2022 				parent->nbranch[pnode->iip].pnode = pnode;
2023 				path[h].ptr.pnode = pnode;
2024 				path[h].in_tree = 1;
2025 				update_cats(c, pnode);
2026 				c->pnodes_have += 1;
2027 			}
2028 			err = dbg_check_lpt_nodes(c, (struct ubifs_cnode *)
2029 						  c->nroot, 0, 0);
2030 			if (err)
2031 				goto out;
2032 			err = dbg_check_cats(c);
2033 			if (err)
2034 				goto out;
2035 		}
2036 		if (ret & LPT_SCAN_STOP) {
2037 			err = 0;
2038 			break;
2039 		}
2040 		/* Get the next lprops */
2041 		if (lnum == end_lnum) {
2042 			/*
2043 			 * We got to the end without finding what we were
2044 			 * looking for
2045 			 */
2046 			err = -ENOSPC;
2047 			goto out;
2048 		}
2049 		if (lnum + 1 >= c->leb_cnt) {
2050 			/* Wrap-around to the beginning */
2051 			start_lnum = c->main_first;
2052 			goto again;
2053 		}
2054 		if (iip + 1 < UBIFS_LPT_FANOUT) {
2055 			/* Next lprops is in the same pnode */
2056 			iip += 1;
2057 			continue;
2058 		}
2059 		/* We need to get the next pnode. Go up until we can go right */
2060 		iip = pnode->iip;
2061 		while (1) {
2062 			h -= 1;
2063 			ubifs_assert(h >= 0);
2064 			nnode = path[h].ptr.nnode;
2065 			if (iip + 1 < UBIFS_LPT_FANOUT)
2066 				break;
2067 			iip = nnode->iip;
2068 		}
2069 		/* Go right */
2070 		iip += 1;
2071 		/* Descend to the pnode */
2072 		h += 1;
2073 		for (; h < c->lpt_hght; h++) {
2074 			nnode = scan_get_nnode(c, path + h, nnode, iip);
2075 			if (IS_ERR(nnode)) {
2076 				err = PTR_ERR(nnode);
2077 				goto out;
2078 			}
2079 			iip = 0;
2080 		}
2081 		pnode = scan_get_pnode(c, path + h, nnode, iip);
2082 		if (IS_ERR(pnode)) {
2083 			err = PTR_ERR(pnode);
2084 			goto out;
2085 		}
2086 		iip = 0;
2087 	}
2088 out:
2089 	kfree(path);
2090 	return err;
2091 }
2092 
2093 /**
2094  * dbg_chk_pnode - check a pnode.
2095  * @c: the UBIFS file-system description object
2096  * @pnode: pnode to check
2097  * @col: pnode column
2098  *
2099  * This function returns %0 on success and a negative error code on failure.
2100  */
2101 static int dbg_chk_pnode(struct ubifs_info *c, struct ubifs_pnode *pnode,
2102 			 int col)
2103 {
2104 	int i;
2105 
2106 	if (pnode->num != col) {
2107 		ubifs_err("pnode num %d expected %d parent num %d iip %d",
2108 			  pnode->num, col, pnode->parent->num, pnode->iip);
2109 		return -EINVAL;
2110 	}
2111 	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
2112 		struct ubifs_lprops *lp, *lprops = &pnode->lprops[i];
2113 		int lnum = (pnode->num << UBIFS_LPT_FANOUT_SHIFT) + i +
2114 			   c->main_first;
2115 		int found, cat = lprops->flags & LPROPS_CAT_MASK;
2116 		struct ubifs_lpt_heap *heap;
2117 		struct list_head *list = NULL;
2118 
2119 		if (lnum >= c->leb_cnt)
2120 			continue;
2121 		if (lprops->lnum != lnum) {
2122 			ubifs_err("bad LEB number %d expected %d",
2123 				  lprops->lnum, lnum);
2124 			return -EINVAL;
2125 		}
2126 		if (lprops->flags & LPROPS_TAKEN) {
2127 			if (cat != LPROPS_UNCAT) {
2128 				ubifs_err("LEB %d taken but not uncat %d",
2129 					  lprops->lnum, cat);
2130 				return -EINVAL;
2131 			}
2132 			continue;
2133 		}
2134 		if (lprops->flags & LPROPS_INDEX) {
2135 			switch (cat) {
2136 			case LPROPS_UNCAT:
2137 			case LPROPS_DIRTY_IDX:
2138 			case LPROPS_FRDI_IDX:
2139 				break;
2140 			default:
2141 				ubifs_err("LEB %d index but cat %d",
2142 					  lprops->lnum, cat);
2143 				return -EINVAL;
2144 			}
2145 		} else {
2146 			switch (cat) {
2147 			case LPROPS_UNCAT:
2148 			case LPROPS_DIRTY:
2149 			case LPROPS_FREE:
2150 			case LPROPS_EMPTY:
2151 			case LPROPS_FREEABLE:
2152 				break;
2153 			default:
2154 				ubifs_err("LEB %d not index but cat %d",
2155 					  lprops->lnum, cat);
2156 				return -EINVAL;
2157 			}
2158 		}
2159 		switch (cat) {
2160 		case LPROPS_UNCAT:
2161 			list = &c->uncat_list;
2162 			break;
2163 		case LPROPS_EMPTY:
2164 			list = &c->empty_list;
2165 			break;
2166 		case LPROPS_FREEABLE:
2167 			list = &c->freeable_list;
2168 			break;
2169 		case LPROPS_FRDI_IDX:
2170 			list = &c->frdi_idx_list;
2171 			break;
2172 		}
2173 		found = 0;
2174 		switch (cat) {
2175 		case LPROPS_DIRTY:
2176 		case LPROPS_DIRTY_IDX:
2177 		case LPROPS_FREE:
2178 			heap = &c->lpt_heap[cat - 1];
2179 			if (lprops->hpos < heap->cnt &&
2180 			    heap->arr[lprops->hpos] == lprops)
2181 				found = 1;
2182 			break;
2183 		case LPROPS_UNCAT:
2184 		case LPROPS_EMPTY:
2185 		case LPROPS_FREEABLE:
2186 		case LPROPS_FRDI_IDX:
2187 			list_for_each_entry(lp, list, list)
2188 				if (lprops == lp) {
2189 					found = 1;
2190 					break;
2191 				}
2192 			break;
2193 		}
2194 		if (!found) {
2195 			ubifs_err("LEB %d cat %d not found in cat heap/list",
2196 				  lprops->lnum, cat);
2197 			return -EINVAL;
2198 		}
2199 		switch (cat) {
2200 		case LPROPS_EMPTY:
2201 			if (lprops->free != c->leb_size) {
2202 				ubifs_err("LEB %d cat %d free %d dirty %d",
2203 					  lprops->lnum, cat, lprops->free,
2204 					  lprops->dirty);
2205 				return -EINVAL;
2206 			}
2207 		case LPROPS_FREEABLE:
2208 		case LPROPS_FRDI_IDX:
2209 			if (lprops->free + lprops->dirty != c->leb_size) {
2210 				ubifs_err("LEB %d cat %d free %d dirty %d",
2211 					  lprops->lnum, cat, lprops->free,
2212 					  lprops->dirty);
2213 				return -EINVAL;
2214 			}
2215 		}
2216 	}
2217 	return 0;
2218 }
2219 
2220 /**
2221  * dbg_check_lpt_nodes - check nnodes and pnodes.
2222  * @c: the UBIFS file-system description object
2223  * @cnode: next cnode (nnode or pnode) to check
2224  * @row: row of cnode (root is zero)
2225  * @col: column of cnode (leftmost is zero)
2226  *
2227  * This function returns %0 on success and a negative error code on failure.
2228  */
2229 int dbg_check_lpt_nodes(struct ubifs_info *c, struct ubifs_cnode *cnode,
2230 			int row, int col)
2231 {
2232 	struct ubifs_nnode *nnode, *nn;
2233 	struct ubifs_cnode *cn;
2234 	int num, iip = 0, err;
2235 
2236 	if (!dbg_is_chk_lprops(c))
2237 		return 0;
2238 
2239 	while (cnode) {
2240 		ubifs_assert(row >= 0);
2241 		nnode = cnode->parent;
2242 		if (cnode->level) {
2243 			/* cnode is a nnode */
2244 			num = calc_nnode_num(row, col);
2245 			if (cnode->num != num) {
2246 				ubifs_err("nnode num %d expected %d parent num %d iip %d",
2247 					  cnode->num, num,
2248 					  (nnode ? nnode->num : 0), cnode->iip);
2249 				return -EINVAL;
2250 			}
2251 			nn = (struct ubifs_nnode *)cnode;
2252 			while (iip < UBIFS_LPT_FANOUT) {
2253 				cn = nn->nbranch[iip].cnode;
2254 				if (cn) {
2255 					/* Go down */
2256 					row += 1;
2257 					col <<= UBIFS_LPT_FANOUT_SHIFT;
2258 					col += iip;
2259 					iip = 0;
2260 					cnode = cn;
2261 					break;
2262 				}
2263 				/* Go right */
2264 				iip += 1;
2265 			}
2266 			if (iip < UBIFS_LPT_FANOUT)
2267 				continue;
2268 		} else {
2269 			struct ubifs_pnode *pnode;
2270 
2271 			/* cnode is a pnode */
2272 			pnode = (struct ubifs_pnode *)cnode;
2273 			err = dbg_chk_pnode(c, pnode, col);
2274 			if (err)
2275 				return err;
2276 		}
2277 		/* Go up and to the right */
2278 		row -= 1;
2279 		col >>= UBIFS_LPT_FANOUT_SHIFT;
2280 		iip = cnode->iip + 1;
2281 		cnode = (struct ubifs_cnode *)nnode;
2282 	}
2283 	return 0;
2284 }
2285