xref: /openbmc/linux/fs/ubifs/lpt.c (revision f759f5b5)
1  // SPDX-License-Identifier: GPL-2.0-only
2  /*
3   * This file is part of UBIFS.
4   *
5   * Copyright (C) 2006-2008 Nokia Corporation.
6   *
7   * Authors: Adrian Hunter
8   *          Artem Bityutskiy (Битюцкий Артём)
9   */
10  
11  /*
12   * This file implements the LEB properties tree (LPT) area. The LPT area
13   * contains the LEB properties tree, a table of LPT area eraseblocks (ltab), and
14   * (for the "big" model) a table of saved LEB numbers (lsave). The LPT area sits
15   * between the log and the orphan area.
16   *
17   * The LPT area is like a miniature self-contained file system. It is required
18   * that it never runs out of space, is fast to access and update, and scales
19   * logarithmically. The LEB properties tree is implemented as a wandering tree
20   * much like the TNC, and the LPT area has its own garbage collection.
21   *
22   * The LPT has two slightly different forms called the "small model" and the
23   * "big model". The small model is used when the entire LEB properties table
24   * can be written into a single eraseblock. In that case, garbage collection
25   * consists of just writing the whole table, which therefore makes all other
26   * eraseblocks reusable. In the case of the big model, dirty eraseblocks are
27   * selected for garbage collection, which consists of marking the clean nodes in
28   * that LEB as dirty, and then only the dirty nodes are written out. Also, in
29   * the case of the big model, a table of LEB numbers is saved so that the entire
30   * LPT does not to be scanned looking for empty eraseblocks when UBIFS is first
31   * mounted.
32   */
33  
34  #include "ubifs.h"
35  #include <linux/crc16.h>
36  #include <linux/math64.h>
37  #include <linux/slab.h>
38  
39  /**
40   * do_calc_lpt_geom - calculate sizes for the LPT area.
41   * @c: the UBIFS file-system description object
42   *
43   * Calculate the sizes of LPT bit fields, nodes, and tree, based on the
44   * properties of the flash and whether LPT is "big" (c->big_lpt).
45   */
46  static void do_calc_lpt_geom(struct ubifs_info *c)
47  {
48  	int i, n, bits, per_leb_wastage, max_pnode_cnt;
49  	long long sz, tot_wastage;
50  
51  	n = c->main_lebs + c->max_leb_cnt - c->leb_cnt;
52  	max_pnode_cnt = DIV_ROUND_UP(n, UBIFS_LPT_FANOUT);
53  
54  	c->lpt_hght = 1;
55  	n = UBIFS_LPT_FANOUT;
56  	while (n < max_pnode_cnt) {
57  		c->lpt_hght += 1;
58  		n <<= UBIFS_LPT_FANOUT_SHIFT;
59  	}
60  
61  	c->pnode_cnt = DIV_ROUND_UP(c->main_lebs, UBIFS_LPT_FANOUT);
62  
63  	n = DIV_ROUND_UP(c->pnode_cnt, UBIFS_LPT_FANOUT);
64  	c->nnode_cnt = n;
65  	for (i = 1; i < c->lpt_hght; i++) {
66  		n = DIV_ROUND_UP(n, UBIFS_LPT_FANOUT);
67  		c->nnode_cnt += n;
68  	}
69  
70  	c->space_bits = fls(c->leb_size) - 3;
71  	c->lpt_lnum_bits = fls(c->lpt_lebs);
72  	c->lpt_offs_bits = fls(c->leb_size - 1);
73  	c->lpt_spc_bits = fls(c->leb_size);
74  
75  	n = DIV_ROUND_UP(c->max_leb_cnt, UBIFS_LPT_FANOUT);
76  	c->pcnt_bits = fls(n - 1);
77  
78  	c->lnum_bits = fls(c->max_leb_cnt - 1);
79  
80  	bits = UBIFS_LPT_CRC_BITS + UBIFS_LPT_TYPE_BITS +
81  	       (c->big_lpt ? c->pcnt_bits : 0) +
82  	       (c->space_bits * 2 + 1) * UBIFS_LPT_FANOUT;
83  	c->pnode_sz = (bits + 7) / 8;
84  
85  	bits = UBIFS_LPT_CRC_BITS + UBIFS_LPT_TYPE_BITS +
86  	       (c->big_lpt ? c->pcnt_bits : 0) +
87  	       (c->lpt_lnum_bits + c->lpt_offs_bits) * UBIFS_LPT_FANOUT;
88  	c->nnode_sz = (bits + 7) / 8;
89  
90  	bits = UBIFS_LPT_CRC_BITS + UBIFS_LPT_TYPE_BITS +
91  	       c->lpt_lebs * c->lpt_spc_bits * 2;
92  	c->ltab_sz = (bits + 7) / 8;
93  
94  	bits = UBIFS_LPT_CRC_BITS + UBIFS_LPT_TYPE_BITS +
95  	       c->lnum_bits * c->lsave_cnt;
96  	c->lsave_sz = (bits + 7) / 8;
97  
98  	/* Calculate the minimum LPT size */
99  	c->lpt_sz = (long long)c->pnode_cnt * c->pnode_sz;
100  	c->lpt_sz += (long long)c->nnode_cnt * c->nnode_sz;
101  	c->lpt_sz += c->ltab_sz;
102  	if (c->big_lpt)
103  		c->lpt_sz += c->lsave_sz;
104  
105  	/* Add wastage */
106  	sz = c->lpt_sz;
107  	per_leb_wastage = max_t(int, c->pnode_sz, c->nnode_sz);
108  	sz += per_leb_wastage;
109  	tot_wastage = per_leb_wastage;
110  	while (sz > c->leb_size) {
111  		sz += per_leb_wastage;
112  		sz -= c->leb_size;
113  		tot_wastage += per_leb_wastage;
114  	}
115  	tot_wastage += ALIGN(sz, c->min_io_size) - sz;
116  	c->lpt_sz += tot_wastage;
117  }
118  
119  /**
120   * ubifs_calc_lpt_geom - calculate and check sizes for the LPT area.
121   * @c: the UBIFS file-system description object
122   *
123   * This function returns %0 on success and a negative error code on failure.
124   */
125  int ubifs_calc_lpt_geom(struct ubifs_info *c)
126  {
127  	int lebs_needed;
128  	long long sz;
129  
130  	do_calc_lpt_geom(c);
131  
132  	/* Verify that lpt_lebs is big enough */
133  	sz = c->lpt_sz * 2; /* Must have at least 2 times the size */
134  	lebs_needed = div_u64(sz + c->leb_size - 1, c->leb_size);
135  	if (lebs_needed > c->lpt_lebs) {
136  		ubifs_err(c, "too few LPT LEBs");
137  		return -EINVAL;
138  	}
139  
140  	/* Verify that ltab fits in a single LEB (since ltab is a single node */
141  	if (c->ltab_sz > c->leb_size) {
142  		ubifs_err(c, "LPT ltab too big");
143  		return -EINVAL;
144  	}
145  
146  	c->check_lpt_free = c->big_lpt;
147  	return 0;
148  }
149  
150  /**
151   * calc_dflt_lpt_geom - calculate default LPT geometry.
152   * @c: the UBIFS file-system description object
153   * @main_lebs: number of main area LEBs is passed and returned here
154   * @big_lpt: whether the LPT area is "big" is returned here
155   *
156   * The size of the LPT area depends on parameters that themselves are dependent
157   * on the size of the LPT area. This function, successively recalculates the LPT
158   * area geometry until the parameters and resultant geometry are consistent.
159   *
160   * This function returns %0 on success and a negative error code on failure.
161   */
162  static int calc_dflt_lpt_geom(struct ubifs_info *c, int *main_lebs,
163  			      int *big_lpt)
164  {
165  	int i, lebs_needed;
166  	long long sz;
167  
168  	/* Start by assuming the minimum number of LPT LEBs */
169  	c->lpt_lebs = UBIFS_MIN_LPT_LEBS;
170  	c->main_lebs = *main_lebs - c->lpt_lebs;
171  	if (c->main_lebs <= 0)
172  		return -EINVAL;
173  
174  	/* And assume we will use the small LPT model */
175  	c->big_lpt = 0;
176  
177  	/*
178  	 * Calculate the geometry based on assumptions above and then see if it
179  	 * makes sense
180  	 */
181  	do_calc_lpt_geom(c);
182  
183  	/* Small LPT model must have lpt_sz < leb_size */
184  	if (c->lpt_sz > c->leb_size) {
185  		/* Nope, so try again using big LPT model */
186  		c->big_lpt = 1;
187  		do_calc_lpt_geom(c);
188  	}
189  
190  	/* Now check there are enough LPT LEBs */
191  	for (i = 0; i < 64 ; i++) {
192  		sz = c->lpt_sz * 4; /* Allow 4 times the size */
193  		lebs_needed = div_u64(sz + c->leb_size - 1, c->leb_size);
194  		if (lebs_needed > c->lpt_lebs) {
195  			/* Not enough LPT LEBs so try again with more */
196  			c->lpt_lebs = lebs_needed;
197  			c->main_lebs = *main_lebs - c->lpt_lebs;
198  			if (c->main_lebs <= 0)
199  				return -EINVAL;
200  			do_calc_lpt_geom(c);
201  			continue;
202  		}
203  		if (c->ltab_sz > c->leb_size) {
204  			ubifs_err(c, "LPT ltab too big");
205  			return -EINVAL;
206  		}
207  		*main_lebs = c->main_lebs;
208  		*big_lpt = c->big_lpt;
209  		return 0;
210  	}
211  	return -EINVAL;
212  }
213  
214  /**
215   * pack_bits - pack bit fields end-to-end.
216   * @c: UBIFS file-system description object
217   * @addr: address at which to pack (passed and next address returned)
218   * @pos: bit position at which to pack (passed and next position returned)
219   * @val: value to pack
220   * @nrbits: number of bits of value to pack (1-32)
221   */
222  static void pack_bits(const struct ubifs_info *c, uint8_t **addr, int *pos, uint32_t val, int nrbits)
223  {
224  	uint8_t *p = *addr;
225  	int b = *pos;
226  
227  	ubifs_assert(c, nrbits > 0);
228  	ubifs_assert(c, nrbits <= 32);
229  	ubifs_assert(c, *pos >= 0);
230  	ubifs_assert(c, *pos < 8);
231  	ubifs_assert(c, (val >> nrbits) == 0 || nrbits == 32);
232  	if (b) {
233  		*p |= ((uint8_t)val) << b;
234  		nrbits += b;
235  		if (nrbits > 8) {
236  			*++p = (uint8_t)(val >>= (8 - b));
237  			if (nrbits > 16) {
238  				*++p = (uint8_t)(val >>= 8);
239  				if (nrbits > 24) {
240  					*++p = (uint8_t)(val >>= 8);
241  					if (nrbits > 32)
242  						*++p = (uint8_t)(val >>= 8);
243  				}
244  			}
245  		}
246  	} else {
247  		*p = (uint8_t)val;
248  		if (nrbits > 8) {
249  			*++p = (uint8_t)(val >>= 8);
250  			if (nrbits > 16) {
251  				*++p = (uint8_t)(val >>= 8);
252  				if (nrbits > 24)
253  					*++p = (uint8_t)(val >>= 8);
254  			}
255  		}
256  	}
257  	b = nrbits & 7;
258  	if (b == 0)
259  		p++;
260  	*addr = p;
261  	*pos = b;
262  }
263  
264  /**
265   * ubifs_unpack_bits - unpack bit fields.
266   * @c: UBIFS file-system description object
267   * @addr: address at which to unpack (passed and next address returned)
268   * @pos: bit position at which to unpack (passed and next position returned)
269   * @nrbits: number of bits of value to unpack (1-32)
270   *
271   * This functions returns the value unpacked.
272   */
273  uint32_t ubifs_unpack_bits(const struct ubifs_info *c, uint8_t **addr, int *pos, int nrbits)
274  {
275  	const int k = 32 - nrbits;
276  	uint8_t *p = *addr;
277  	int b = *pos;
278  	uint32_t val;
279  	const int bytes = (nrbits + b + 7) >> 3;
280  
281  	ubifs_assert(c, nrbits > 0);
282  	ubifs_assert(c, nrbits <= 32);
283  	ubifs_assert(c, *pos >= 0);
284  	ubifs_assert(c, *pos < 8);
285  	if (b) {
286  		switch (bytes) {
287  		case 2:
288  			val = p[1];
289  			break;
290  		case 3:
291  			val = p[1] | ((uint32_t)p[2] << 8);
292  			break;
293  		case 4:
294  			val = p[1] | ((uint32_t)p[2] << 8) |
295  				     ((uint32_t)p[3] << 16);
296  			break;
297  		case 5:
298  			val = p[1] | ((uint32_t)p[2] << 8) |
299  				     ((uint32_t)p[3] << 16) |
300  				     ((uint32_t)p[4] << 24);
301  		}
302  		val <<= (8 - b);
303  		val |= *p >> b;
304  		nrbits += b;
305  	} else {
306  		switch (bytes) {
307  		case 1:
308  			val = p[0];
309  			break;
310  		case 2:
311  			val = p[0] | ((uint32_t)p[1] << 8);
312  			break;
313  		case 3:
314  			val = p[0] | ((uint32_t)p[1] << 8) |
315  				     ((uint32_t)p[2] << 16);
316  			break;
317  		case 4:
318  			val = p[0] | ((uint32_t)p[1] << 8) |
319  				     ((uint32_t)p[2] << 16) |
320  				     ((uint32_t)p[3] << 24);
321  			break;
322  		}
323  	}
324  	val <<= k;
325  	val >>= k;
326  	b = nrbits & 7;
327  	p += nrbits >> 3;
328  	*addr = p;
329  	*pos = b;
330  	ubifs_assert(c, (val >> nrbits) == 0 || nrbits - b == 32);
331  	return val;
332  }
333  
334  /**
335   * ubifs_pack_pnode - pack all the bit fields of a pnode.
336   * @c: UBIFS file-system description object
337   * @buf: buffer into which to pack
338   * @pnode: pnode to pack
339   */
340  void ubifs_pack_pnode(struct ubifs_info *c, void *buf,
341  		      struct ubifs_pnode *pnode)
342  {
343  	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
344  	int i, pos = 0;
345  	uint16_t crc;
346  
347  	pack_bits(c, &addr, &pos, UBIFS_LPT_PNODE, UBIFS_LPT_TYPE_BITS);
348  	if (c->big_lpt)
349  		pack_bits(c, &addr, &pos, pnode->num, c->pcnt_bits);
350  	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
351  		pack_bits(c, &addr, &pos, pnode->lprops[i].free >> 3,
352  			  c->space_bits);
353  		pack_bits(c, &addr, &pos, pnode->lprops[i].dirty >> 3,
354  			  c->space_bits);
355  		if (pnode->lprops[i].flags & LPROPS_INDEX)
356  			pack_bits(c, &addr, &pos, 1, 1);
357  		else
358  			pack_bits(c, &addr, &pos, 0, 1);
359  	}
360  	crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
361  		    c->pnode_sz - UBIFS_LPT_CRC_BYTES);
362  	addr = buf;
363  	pos = 0;
364  	pack_bits(c, &addr, &pos, crc, UBIFS_LPT_CRC_BITS);
365  }
366  
367  /**
368   * ubifs_pack_nnode - pack all the bit fields of a nnode.
369   * @c: UBIFS file-system description object
370   * @buf: buffer into which to pack
371   * @nnode: nnode to pack
372   */
373  void ubifs_pack_nnode(struct ubifs_info *c, void *buf,
374  		      struct ubifs_nnode *nnode)
375  {
376  	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
377  	int i, pos = 0;
378  	uint16_t crc;
379  
380  	pack_bits(c, &addr, &pos, UBIFS_LPT_NNODE, UBIFS_LPT_TYPE_BITS);
381  	if (c->big_lpt)
382  		pack_bits(c, &addr, &pos, nnode->num, c->pcnt_bits);
383  	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
384  		int lnum = nnode->nbranch[i].lnum;
385  
386  		if (lnum == 0)
387  			lnum = c->lpt_last + 1;
388  		pack_bits(c, &addr, &pos, lnum - c->lpt_first, c->lpt_lnum_bits);
389  		pack_bits(c, &addr, &pos, nnode->nbranch[i].offs,
390  			  c->lpt_offs_bits);
391  	}
392  	crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
393  		    c->nnode_sz - UBIFS_LPT_CRC_BYTES);
394  	addr = buf;
395  	pos = 0;
396  	pack_bits(c, &addr, &pos, crc, UBIFS_LPT_CRC_BITS);
397  }
398  
399  /**
400   * ubifs_pack_ltab - pack the LPT's own lprops table.
401   * @c: UBIFS file-system description object
402   * @buf: buffer into which to pack
403   * @ltab: LPT's own lprops table to pack
404   */
405  void ubifs_pack_ltab(struct ubifs_info *c, void *buf,
406  		     struct ubifs_lpt_lprops *ltab)
407  {
408  	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
409  	int i, pos = 0;
410  	uint16_t crc;
411  
412  	pack_bits(c, &addr, &pos, UBIFS_LPT_LTAB, UBIFS_LPT_TYPE_BITS);
413  	for (i = 0; i < c->lpt_lebs; i++) {
414  		pack_bits(c, &addr, &pos, ltab[i].free, c->lpt_spc_bits);
415  		pack_bits(c, &addr, &pos, ltab[i].dirty, c->lpt_spc_bits);
416  	}
417  	crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
418  		    c->ltab_sz - UBIFS_LPT_CRC_BYTES);
419  	addr = buf;
420  	pos = 0;
421  	pack_bits(c, &addr, &pos, crc, UBIFS_LPT_CRC_BITS);
422  }
423  
424  /**
425   * ubifs_pack_lsave - pack the LPT's save table.
426   * @c: UBIFS file-system description object
427   * @buf: buffer into which to pack
428   * @lsave: LPT's save table to pack
429   */
430  void ubifs_pack_lsave(struct ubifs_info *c, void *buf, int *lsave)
431  {
432  	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
433  	int i, pos = 0;
434  	uint16_t crc;
435  
436  	pack_bits(c, &addr, &pos, UBIFS_LPT_LSAVE, UBIFS_LPT_TYPE_BITS);
437  	for (i = 0; i < c->lsave_cnt; i++)
438  		pack_bits(c, &addr, &pos, lsave[i], c->lnum_bits);
439  	crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
440  		    c->lsave_sz - UBIFS_LPT_CRC_BYTES);
441  	addr = buf;
442  	pos = 0;
443  	pack_bits(c, &addr, &pos, crc, UBIFS_LPT_CRC_BITS);
444  }
445  
446  /**
447   * ubifs_add_lpt_dirt - add dirty space to LPT LEB properties.
448   * @c: UBIFS file-system description object
449   * @lnum: LEB number to which to add dirty space
450   * @dirty: amount of dirty space to add
451   */
452  void ubifs_add_lpt_dirt(struct ubifs_info *c, int lnum, int dirty)
453  {
454  	if (!dirty || !lnum)
455  		return;
456  	dbg_lp("LEB %d add %d to %d",
457  	       lnum, dirty, c->ltab[lnum - c->lpt_first].dirty);
458  	ubifs_assert(c, lnum >= c->lpt_first && lnum <= c->lpt_last);
459  	c->ltab[lnum - c->lpt_first].dirty += dirty;
460  }
461  
462  /**
463   * set_ltab - set LPT LEB properties.
464   * @c: UBIFS file-system description object
465   * @lnum: LEB number
466   * @free: amount of free space
467   * @dirty: amount of dirty space
468   */
469  static void set_ltab(struct ubifs_info *c, int lnum, int free, int dirty)
470  {
471  	dbg_lp("LEB %d free %d dirty %d to %d %d",
472  	       lnum, c->ltab[lnum - c->lpt_first].free,
473  	       c->ltab[lnum - c->lpt_first].dirty, free, dirty);
474  	ubifs_assert(c, lnum >= c->lpt_first && lnum <= c->lpt_last);
475  	c->ltab[lnum - c->lpt_first].free = free;
476  	c->ltab[lnum - c->lpt_first].dirty = dirty;
477  }
478  
479  /**
480   * ubifs_add_nnode_dirt - add dirty space to LPT LEB properties.
481   * @c: UBIFS file-system description object
482   * @nnode: nnode for which to add dirt
483   */
484  void ubifs_add_nnode_dirt(struct ubifs_info *c, struct ubifs_nnode *nnode)
485  {
486  	struct ubifs_nnode *np = nnode->parent;
487  
488  	if (np)
489  		ubifs_add_lpt_dirt(c, np->nbranch[nnode->iip].lnum,
490  				   c->nnode_sz);
491  	else {
492  		ubifs_add_lpt_dirt(c, c->lpt_lnum, c->nnode_sz);
493  		if (!(c->lpt_drty_flgs & LTAB_DIRTY)) {
494  			c->lpt_drty_flgs |= LTAB_DIRTY;
495  			ubifs_add_lpt_dirt(c, c->ltab_lnum, c->ltab_sz);
496  		}
497  	}
498  }
499  
500  /**
501   * add_pnode_dirt - add dirty space to LPT LEB properties.
502   * @c: UBIFS file-system description object
503   * @pnode: pnode for which to add dirt
504   */
505  static void add_pnode_dirt(struct ubifs_info *c, struct ubifs_pnode *pnode)
506  {
507  	ubifs_add_lpt_dirt(c, pnode->parent->nbranch[pnode->iip].lnum,
508  			   c->pnode_sz);
509  }
510  
511  /**
512   * calc_nnode_num - calculate nnode number.
513   * @row: the row in the tree (root is zero)
514   * @col: the column in the row (leftmost is zero)
515   *
516   * The nnode number is a number that uniquely identifies a nnode and can be used
517   * easily to traverse the tree from the root to that nnode.
518   *
519   * This function calculates and returns the nnode number for the nnode at @row
520   * and @col.
521   */
522  static int calc_nnode_num(int row, int col)
523  {
524  	int num, bits;
525  
526  	num = 1;
527  	while (row--) {
528  		bits = (col & (UBIFS_LPT_FANOUT - 1));
529  		col >>= UBIFS_LPT_FANOUT_SHIFT;
530  		num <<= UBIFS_LPT_FANOUT_SHIFT;
531  		num |= bits;
532  	}
533  	return num;
534  }
535  
536  /**
537   * calc_nnode_num_from_parent - calculate nnode number.
538   * @c: UBIFS file-system description object
539   * @parent: parent nnode
540   * @iip: index in parent
541   *
542   * The nnode number is a number that uniquely identifies a nnode and can be used
543   * easily to traverse the tree from the root to that nnode.
544   *
545   * This function calculates and returns the nnode number based on the parent's
546   * nnode number and the index in parent.
547   */
548  static int calc_nnode_num_from_parent(const struct ubifs_info *c,
549  				      struct ubifs_nnode *parent, int iip)
550  {
551  	int num, shft;
552  
553  	if (!parent)
554  		return 1;
555  	shft = (c->lpt_hght - parent->level) * UBIFS_LPT_FANOUT_SHIFT;
556  	num = parent->num ^ (1 << shft);
557  	num |= (UBIFS_LPT_FANOUT + iip) << shft;
558  	return num;
559  }
560  
561  /**
562   * calc_pnode_num_from_parent - calculate pnode number.
563   * @c: UBIFS file-system description object
564   * @parent: parent nnode
565   * @iip: index in parent
566   *
567   * The pnode number is a number that uniquely identifies a pnode and can be used
568   * easily to traverse the tree from the root to that pnode.
569   *
570   * This function calculates and returns the pnode number based on the parent's
571   * nnode number and the index in parent.
572   */
573  static int calc_pnode_num_from_parent(const struct ubifs_info *c,
574  				      struct ubifs_nnode *parent, int iip)
575  {
576  	int i, n = c->lpt_hght - 1, pnum = parent->num, num = 0;
577  
578  	for (i = 0; i < n; i++) {
579  		num <<= UBIFS_LPT_FANOUT_SHIFT;
580  		num |= pnum & (UBIFS_LPT_FANOUT - 1);
581  		pnum >>= UBIFS_LPT_FANOUT_SHIFT;
582  	}
583  	num <<= UBIFS_LPT_FANOUT_SHIFT;
584  	num |= iip;
585  	return num;
586  }
587  
588  /**
589   * ubifs_create_dflt_lpt - create default LPT.
590   * @c: UBIFS file-system description object
591   * @main_lebs: number of main area LEBs is passed and returned here
592   * @lpt_first: LEB number of first LPT LEB
593   * @lpt_lebs: number of LEBs for LPT is passed and returned here
594   * @big_lpt: use big LPT model is passed and returned here
595   * @hash: hash of the LPT is returned here
596   *
597   * This function returns %0 on success and a negative error code on failure.
598   */
599  int ubifs_create_dflt_lpt(struct ubifs_info *c, int *main_lebs, int lpt_first,
600  			  int *lpt_lebs, int *big_lpt, u8 *hash)
601  {
602  	int lnum, err = 0, node_sz, iopos, i, j, cnt, len, alen, row;
603  	int blnum, boffs, bsz, bcnt;
604  	struct ubifs_pnode *pnode = NULL;
605  	struct ubifs_nnode *nnode = NULL;
606  	void *buf = NULL, *p;
607  	struct ubifs_lpt_lprops *ltab = NULL;
608  	int *lsave = NULL;
609  	struct shash_desc *desc;
610  
611  	err = calc_dflt_lpt_geom(c, main_lebs, big_lpt);
612  	if (err)
613  		return err;
614  	*lpt_lebs = c->lpt_lebs;
615  
616  	/* Needed by 'ubifs_pack_nnode()' and 'set_ltab()' */
617  	c->lpt_first = lpt_first;
618  	/* Needed by 'set_ltab()' */
619  	c->lpt_last = lpt_first + c->lpt_lebs - 1;
620  	/* Needed by 'ubifs_pack_lsave()' */
621  	c->main_first = c->leb_cnt - *main_lebs;
622  
623  	desc = ubifs_hash_get_desc(c);
624  	if (IS_ERR(desc))
625  		return PTR_ERR(desc);
626  
627  	lsave = kmalloc_array(c->lsave_cnt, sizeof(int), 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(array_size(sizeof(struct ubifs_lpt_lprops),
632  				  c->lpt_lebs));
633  	if (!pnode || !nnode || !buf || !ltab || !lsave) {
634  		err = -ENOMEM;
635  		goto out;
636  	}
637  
638  	ubifs_assert(c, !c->ltab);
639  	c->ltab = ltab; /* Needed by set_ltab */
640  
641  	/* Initialize LPT's own lprops */
642  	for (i = 0; i < c->lpt_lebs; i++) {
643  		ltab[i].free = c->leb_size;
644  		ltab[i].dirty = 0;
645  		ltab[i].tgc = 0;
646  		ltab[i].cmt = 0;
647  	}
648  
649  	lnum = lpt_first;
650  	p = buf;
651  	/* Number of leaf nodes (pnodes) */
652  	cnt = c->pnode_cnt;
653  
654  	/*
655  	 * The first pnode contains the LEB properties for the LEBs that contain
656  	 * the root inode node and the root index node of the index tree.
657  	 */
658  	node_sz = ALIGN(ubifs_idx_node_sz(c, 1), 8);
659  	iopos = ALIGN(node_sz, c->min_io_size);
660  	pnode->lprops[0].free = c->leb_size - iopos;
661  	pnode->lprops[0].dirty = iopos - node_sz;
662  	pnode->lprops[0].flags = LPROPS_INDEX;
663  
664  	node_sz = UBIFS_INO_NODE_SZ;
665  	iopos = ALIGN(node_sz, c->min_io_size);
666  	pnode->lprops[1].free = c->leb_size - iopos;
667  	pnode->lprops[1].dirty = iopos - node_sz;
668  
669  	for (i = 2; i < UBIFS_LPT_FANOUT; i++)
670  		pnode->lprops[i].free = c->leb_size;
671  
672  	/* Add first pnode */
673  	ubifs_pack_pnode(c, p, pnode);
674  	err = ubifs_shash_update(c, desc, p, c->pnode_sz);
675  	if (err)
676  		goto out;
677  
678  	p += c->pnode_sz;
679  	len = c->pnode_sz;
680  	pnode->num += 1;
681  
682  	/* Reset pnode values for remaining pnodes */
683  	pnode->lprops[0].free = c->leb_size;
684  	pnode->lprops[0].dirty = 0;
685  	pnode->lprops[0].flags = 0;
686  
687  	pnode->lprops[1].free = c->leb_size;
688  	pnode->lprops[1].dirty = 0;
689  
690  	/*
691  	 * To calculate the internal node branches, we keep information about
692  	 * the level below.
693  	 */
694  	blnum = lnum; /* LEB number of level below */
695  	boffs = 0; /* Offset of level below */
696  	bcnt = cnt; /* Number of nodes in level below */
697  	bsz = c->pnode_sz; /* Size of nodes in level below */
698  
699  	/* Add all remaining pnodes */
700  	for (i = 1; i < cnt; i++) {
701  		if (len + c->pnode_sz > c->leb_size) {
702  			alen = ALIGN(len, c->min_io_size);
703  			set_ltab(c, lnum, c->leb_size - alen, alen - len);
704  			memset(p, 0xff, alen - len);
705  			err = ubifs_leb_change(c, lnum++, buf, alen);
706  			if (err)
707  				goto out;
708  			p = buf;
709  			len = 0;
710  		}
711  		ubifs_pack_pnode(c, p, pnode);
712  		err = ubifs_shash_update(c, desc, p, c->pnode_sz);
713  		if (err)
714  			goto out;
715  
716  		p += c->pnode_sz;
717  		len += c->pnode_sz;
718  		/*
719  		 * pnodes are simply numbered left to right starting at zero,
720  		 * which means the pnode number can be used easily to traverse
721  		 * down the tree to the corresponding pnode.
722  		 */
723  		pnode->num += 1;
724  	}
725  
726  	row = 0;
727  	for (i = UBIFS_LPT_FANOUT; cnt > i; i <<= UBIFS_LPT_FANOUT_SHIFT)
728  		row += 1;
729  	/* Add all nnodes, one level at a time */
730  	while (1) {
731  		/* Number of internal nodes (nnodes) at next level */
732  		cnt = DIV_ROUND_UP(cnt, UBIFS_LPT_FANOUT);
733  		for (i = 0; i < cnt; i++) {
734  			if (len + c->nnode_sz > c->leb_size) {
735  				alen = ALIGN(len, c->min_io_size);
736  				set_ltab(c, lnum, c->leb_size - alen,
737  					    alen - len);
738  				memset(p, 0xff, alen - len);
739  				err = ubifs_leb_change(c, lnum++, buf, alen);
740  				if (err)
741  					goto out;
742  				p = buf;
743  				len = 0;
744  			}
745  			/* Only 1 nnode at this level, so it is the root */
746  			if (cnt == 1) {
747  				c->lpt_lnum = lnum;
748  				c->lpt_offs = len;
749  			}
750  			/* Set branches to the level below */
751  			for (j = 0; j < UBIFS_LPT_FANOUT; j++) {
752  				if (bcnt) {
753  					if (boffs + bsz > c->leb_size) {
754  						blnum += 1;
755  						boffs = 0;
756  					}
757  					nnode->nbranch[j].lnum = blnum;
758  					nnode->nbranch[j].offs = boffs;
759  					boffs += bsz;
760  					bcnt--;
761  				} else {
762  					nnode->nbranch[j].lnum = 0;
763  					nnode->nbranch[j].offs = 0;
764  				}
765  			}
766  			nnode->num = calc_nnode_num(row, i);
767  			ubifs_pack_nnode(c, p, nnode);
768  			p += c->nnode_sz;
769  			len += c->nnode_sz;
770  		}
771  		/* Only 1 nnode at this level, so it is the root */
772  		if (cnt == 1)
773  			break;
774  		/* Update the information about the level below */
775  		bcnt = cnt;
776  		bsz = c->nnode_sz;
777  		row -= 1;
778  	}
779  
780  	if (*big_lpt) {
781  		/* Need to add LPT's save table */
782  		if (len + c->lsave_sz > c->leb_size) {
783  			alen = ALIGN(len, c->min_io_size);
784  			set_ltab(c, lnum, c->leb_size - alen, alen - len);
785  			memset(p, 0xff, alen - len);
786  			err = ubifs_leb_change(c, lnum++, buf, alen);
787  			if (err)
788  				goto out;
789  			p = buf;
790  			len = 0;
791  		}
792  
793  		c->lsave_lnum = lnum;
794  		c->lsave_offs = len;
795  
796  		for (i = 0; i < c->lsave_cnt && i < *main_lebs; i++)
797  			lsave[i] = c->main_first + i;
798  		for (; i < c->lsave_cnt; i++)
799  			lsave[i] = c->main_first;
800  
801  		ubifs_pack_lsave(c, p, lsave);
802  		p += c->lsave_sz;
803  		len += c->lsave_sz;
804  	}
805  
806  	/* Need to add LPT's own LEB properties table */
807  	if (len + c->ltab_sz > c->leb_size) {
808  		alen = ALIGN(len, c->min_io_size);
809  		set_ltab(c, lnum, c->leb_size - alen, alen - len);
810  		memset(p, 0xff, alen - len);
811  		err = ubifs_leb_change(c, lnum++, buf, alen);
812  		if (err)
813  			goto out;
814  		p = buf;
815  		len = 0;
816  	}
817  
818  	c->ltab_lnum = lnum;
819  	c->ltab_offs = len;
820  
821  	/* Update ltab before packing it */
822  	len += c->ltab_sz;
823  	alen = ALIGN(len, c->min_io_size);
824  	set_ltab(c, lnum, c->leb_size - alen, alen - len);
825  
826  	ubifs_pack_ltab(c, p, ltab);
827  	p += c->ltab_sz;
828  
829  	/* Write remaining buffer */
830  	memset(p, 0xff, alen - len);
831  	err = ubifs_leb_change(c, lnum, buf, alen);
832  	if (err)
833  		goto out;
834  
835  	err = ubifs_shash_final(c, desc, hash);
836  	if (err)
837  		goto out;
838  
839  	c->nhead_lnum = lnum;
840  	c->nhead_offs = ALIGN(len, c->min_io_size);
841  
842  	dbg_lp("space_bits %d", c->space_bits);
843  	dbg_lp("lpt_lnum_bits %d", c->lpt_lnum_bits);
844  	dbg_lp("lpt_offs_bits %d", c->lpt_offs_bits);
845  	dbg_lp("lpt_spc_bits %d", c->lpt_spc_bits);
846  	dbg_lp("pcnt_bits %d", c->pcnt_bits);
847  	dbg_lp("lnum_bits %d", c->lnum_bits);
848  	dbg_lp("pnode_sz %d", c->pnode_sz);
849  	dbg_lp("nnode_sz %d", c->nnode_sz);
850  	dbg_lp("ltab_sz %d", c->ltab_sz);
851  	dbg_lp("lsave_sz %d", c->lsave_sz);
852  	dbg_lp("lsave_cnt %d", c->lsave_cnt);
853  	dbg_lp("lpt_hght %d", c->lpt_hght);
854  	dbg_lp("big_lpt %u", c->big_lpt);
855  	dbg_lp("LPT root is at %d:%d", c->lpt_lnum, c->lpt_offs);
856  	dbg_lp("LPT head is at %d:%d", c->nhead_lnum, c->nhead_offs);
857  	dbg_lp("LPT ltab is at %d:%d", c->ltab_lnum, c->ltab_offs);
858  	if (c->big_lpt)
859  		dbg_lp("LPT lsave is at %d:%d", c->lsave_lnum, c->lsave_offs);
860  out:
861  	c->ltab = NULL;
862  	kfree(desc);
863  	kfree(lsave);
864  	vfree(ltab);
865  	vfree(buf);
866  	kfree(nnode);
867  	kfree(pnode);
868  	return err;
869  }
870  
871  /**
872   * update_cats - add LEB properties of a pnode to LEB category lists and heaps.
873   * @c: UBIFS file-system description object
874   * @pnode: pnode
875   *
876   * When a pnode is loaded into memory, the LEB properties it contains are added,
877   * by this function, to the LEB category lists and heaps.
878   */
879  static void update_cats(struct ubifs_info *c, struct ubifs_pnode *pnode)
880  {
881  	int i;
882  
883  	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
884  		int cat = pnode->lprops[i].flags & LPROPS_CAT_MASK;
885  		int lnum = pnode->lprops[i].lnum;
886  
887  		if (!lnum)
888  			return;
889  		ubifs_add_to_cat(c, &pnode->lprops[i], cat);
890  	}
891  }
892  
893  /**
894   * replace_cats - add LEB properties of a pnode to LEB category lists and heaps.
895   * @c: UBIFS file-system description object
896   * @old_pnode: pnode copied
897   * @new_pnode: pnode copy
898   *
899   * During commit it is sometimes necessary to copy a pnode
900   * (see dirty_cow_pnode).  When that happens, references in
901   * category lists and heaps must be replaced.  This function does that.
902   */
903  static void replace_cats(struct ubifs_info *c, struct ubifs_pnode *old_pnode,
904  			 struct ubifs_pnode *new_pnode)
905  {
906  	int i;
907  
908  	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
909  		if (!new_pnode->lprops[i].lnum)
910  			return;
911  		ubifs_replace_cat(c, &old_pnode->lprops[i],
912  				  &new_pnode->lprops[i]);
913  	}
914  }
915  
916  /**
917   * check_lpt_crc - check LPT node crc is correct.
918   * @c: UBIFS file-system description object
919   * @buf: buffer containing node
920   * @len: length of node
921   *
922   * This function returns %0 on success and a negative error code on failure.
923   */
924  static int check_lpt_crc(const struct ubifs_info *c, void *buf, int len)
925  {
926  	int pos = 0;
927  	uint8_t *addr = buf;
928  	uint16_t crc, calc_crc;
929  
930  	crc = ubifs_unpack_bits(c, &addr, &pos, UBIFS_LPT_CRC_BITS);
931  	calc_crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
932  			 len - UBIFS_LPT_CRC_BYTES);
933  	if (crc != calc_crc) {
934  		ubifs_err(c, "invalid crc in LPT node: crc %hx calc %hx",
935  			  crc, calc_crc);
936  		dump_stack();
937  		return -EINVAL;
938  	}
939  	return 0;
940  }
941  
942  /**
943   * check_lpt_type - check LPT node type is correct.
944   * @c: UBIFS file-system description object
945   * @addr: address of type bit field is passed and returned updated here
946   * @pos: position of type bit field is passed and returned updated here
947   * @type: expected type
948   *
949   * This function returns %0 on success and a negative error code on failure.
950   */
951  static int check_lpt_type(const struct ubifs_info *c, uint8_t **addr,
952  			  int *pos, int type)
953  {
954  	int node_type;
955  
956  	node_type = ubifs_unpack_bits(c, addr, pos, UBIFS_LPT_TYPE_BITS);
957  	if (node_type != type) {
958  		ubifs_err(c, "invalid type (%d) in LPT node type %d",
959  			  node_type, type);
960  		dump_stack();
961  		return -EINVAL;
962  	}
963  	return 0;
964  }
965  
966  /**
967   * unpack_pnode - unpack a pnode.
968   * @c: UBIFS file-system description object
969   * @buf: buffer containing packed pnode to unpack
970   * @pnode: pnode structure to fill
971   *
972   * This function returns %0 on success and a negative error code on failure.
973   */
974  static int unpack_pnode(const struct ubifs_info *c, void *buf,
975  			struct ubifs_pnode *pnode)
976  {
977  	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
978  	int i, pos = 0, err;
979  
980  	err = check_lpt_type(c, &addr, &pos, UBIFS_LPT_PNODE);
981  	if (err)
982  		return err;
983  	if (c->big_lpt)
984  		pnode->num = ubifs_unpack_bits(c, &addr, &pos, c->pcnt_bits);
985  	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
986  		struct ubifs_lprops * const lprops = &pnode->lprops[i];
987  
988  		lprops->free = ubifs_unpack_bits(c, &addr, &pos, c->space_bits);
989  		lprops->free <<= 3;
990  		lprops->dirty = ubifs_unpack_bits(c, &addr, &pos, c->space_bits);
991  		lprops->dirty <<= 3;
992  
993  		if (ubifs_unpack_bits(c, &addr, &pos, 1))
994  			lprops->flags = LPROPS_INDEX;
995  		else
996  			lprops->flags = 0;
997  		lprops->flags |= ubifs_categorize_lprops(c, lprops);
998  	}
999  	err = check_lpt_crc(c, buf, c->pnode_sz);
1000  	return err;
1001  }
1002  
1003  /**
1004   * ubifs_unpack_nnode - unpack a nnode.
1005   * @c: UBIFS file-system description object
1006   * @buf: buffer containing packed nnode to unpack
1007   * @nnode: nnode structure to fill
1008   *
1009   * This function returns %0 on success and a negative error code on failure.
1010   */
1011  int ubifs_unpack_nnode(const struct ubifs_info *c, void *buf,
1012  		       struct ubifs_nnode *nnode)
1013  {
1014  	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
1015  	int i, pos = 0, err;
1016  
1017  	err = check_lpt_type(c, &addr, &pos, UBIFS_LPT_NNODE);
1018  	if (err)
1019  		return err;
1020  	if (c->big_lpt)
1021  		nnode->num = ubifs_unpack_bits(c, &addr, &pos, c->pcnt_bits);
1022  	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1023  		int lnum;
1024  
1025  		lnum = ubifs_unpack_bits(c, &addr, &pos, c->lpt_lnum_bits) +
1026  		       c->lpt_first;
1027  		if (lnum == c->lpt_last + 1)
1028  			lnum = 0;
1029  		nnode->nbranch[i].lnum = lnum;
1030  		nnode->nbranch[i].offs = ubifs_unpack_bits(c, &addr, &pos,
1031  						     c->lpt_offs_bits);
1032  	}
1033  	err = check_lpt_crc(c, buf, c->nnode_sz);
1034  	return err;
1035  }
1036  
1037  /**
1038   * unpack_ltab - unpack the LPT's own lprops table.
1039   * @c: UBIFS file-system description object
1040   * @buf: buffer from which to unpack
1041   *
1042   * This function returns %0 on success and a negative error code on failure.
1043   */
1044  static int unpack_ltab(const struct ubifs_info *c, void *buf)
1045  {
1046  	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
1047  	int i, pos = 0, err;
1048  
1049  	err = check_lpt_type(c, &addr, &pos, UBIFS_LPT_LTAB);
1050  	if (err)
1051  		return err;
1052  	for (i = 0; i < c->lpt_lebs; i++) {
1053  		int free = ubifs_unpack_bits(c, &addr, &pos, c->lpt_spc_bits);
1054  		int dirty = ubifs_unpack_bits(c, &addr, &pos, c->lpt_spc_bits);
1055  
1056  		if (free < 0 || free > c->leb_size || dirty < 0 ||
1057  		    dirty > c->leb_size || free + dirty > c->leb_size)
1058  			return -EINVAL;
1059  
1060  		c->ltab[i].free = free;
1061  		c->ltab[i].dirty = dirty;
1062  		c->ltab[i].tgc = 0;
1063  		c->ltab[i].cmt = 0;
1064  	}
1065  	err = check_lpt_crc(c, buf, c->ltab_sz);
1066  	return err;
1067  }
1068  
1069  /**
1070   * unpack_lsave - unpack the LPT's save table.
1071   * @c: UBIFS file-system description object
1072   * @buf: buffer from which to unpack
1073   *
1074   * This function returns %0 on success and a negative error code on failure.
1075   */
1076  static int unpack_lsave(const struct ubifs_info *c, void *buf)
1077  {
1078  	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
1079  	int i, pos = 0, err;
1080  
1081  	err = check_lpt_type(c, &addr, &pos, UBIFS_LPT_LSAVE);
1082  	if (err)
1083  		return err;
1084  	for (i = 0; i < c->lsave_cnt; i++) {
1085  		int lnum = ubifs_unpack_bits(c, &addr, &pos, c->lnum_bits);
1086  
1087  		if (lnum < c->main_first || lnum >= c->leb_cnt)
1088  			return -EINVAL;
1089  		c->lsave[i] = lnum;
1090  	}
1091  	err = check_lpt_crc(c, buf, c->lsave_sz);
1092  	return err;
1093  }
1094  
1095  /**
1096   * validate_nnode - validate a nnode.
1097   * @c: UBIFS file-system description object
1098   * @nnode: nnode to validate
1099   * @parent: parent nnode (or NULL for the root nnode)
1100   * @iip: index in parent
1101   *
1102   * This function returns %0 on success and a negative error code on failure.
1103   */
1104  static int validate_nnode(const struct ubifs_info *c, struct ubifs_nnode *nnode,
1105  			  struct ubifs_nnode *parent, int iip)
1106  {
1107  	int i, lvl, max_offs;
1108  
1109  	if (c->big_lpt) {
1110  		int num = calc_nnode_num_from_parent(c, parent, iip);
1111  
1112  		if (nnode->num != num)
1113  			return -EINVAL;
1114  	}
1115  	lvl = parent ? parent->level - 1 : c->lpt_hght;
1116  	if (lvl < 1)
1117  		return -EINVAL;
1118  	if (lvl == 1)
1119  		max_offs = c->leb_size - c->pnode_sz;
1120  	else
1121  		max_offs = c->leb_size - c->nnode_sz;
1122  	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1123  		int lnum = nnode->nbranch[i].lnum;
1124  		int offs = nnode->nbranch[i].offs;
1125  
1126  		if (lnum == 0) {
1127  			if (offs != 0)
1128  				return -EINVAL;
1129  			continue;
1130  		}
1131  		if (lnum < c->lpt_first || lnum > c->lpt_last)
1132  			return -EINVAL;
1133  		if (offs < 0 || offs > max_offs)
1134  			return -EINVAL;
1135  	}
1136  	return 0;
1137  }
1138  
1139  /**
1140   * validate_pnode - validate a pnode.
1141   * @c: UBIFS file-system description object
1142   * @pnode: pnode to validate
1143   * @parent: parent nnode
1144   * @iip: index in parent
1145   *
1146   * This function returns %0 on success and a negative error code on failure.
1147   */
1148  static int validate_pnode(const struct ubifs_info *c, struct ubifs_pnode *pnode,
1149  			  struct ubifs_nnode *parent, int iip)
1150  {
1151  	int i;
1152  
1153  	if (c->big_lpt) {
1154  		int num = calc_pnode_num_from_parent(c, parent, iip);
1155  
1156  		if (pnode->num != num)
1157  			return -EINVAL;
1158  	}
1159  	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1160  		int free = pnode->lprops[i].free;
1161  		int dirty = pnode->lprops[i].dirty;
1162  
1163  		if (free < 0 || free > c->leb_size || free % c->min_io_size ||
1164  		    (free & 7))
1165  			return -EINVAL;
1166  		if (dirty < 0 || dirty > c->leb_size || (dirty & 7))
1167  			return -EINVAL;
1168  		if (dirty + free > c->leb_size)
1169  			return -EINVAL;
1170  	}
1171  	return 0;
1172  }
1173  
1174  /**
1175   * set_pnode_lnum - set LEB numbers on a pnode.
1176   * @c: UBIFS file-system description object
1177   * @pnode: pnode to update
1178   *
1179   * This function calculates the LEB numbers for the LEB properties it contains
1180   * based on the pnode number.
1181   */
1182  static void set_pnode_lnum(const struct ubifs_info *c,
1183  			   struct ubifs_pnode *pnode)
1184  {
1185  	int i, lnum;
1186  
1187  	lnum = (pnode->num << UBIFS_LPT_FANOUT_SHIFT) + c->main_first;
1188  	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1189  		if (lnum >= c->leb_cnt)
1190  			return;
1191  		pnode->lprops[i].lnum = lnum++;
1192  	}
1193  }
1194  
1195  /**
1196   * ubifs_read_nnode - read a nnode from flash and link it to the tree in memory.
1197   * @c: UBIFS file-system description object
1198   * @parent: parent nnode (or NULL for the root)
1199   * @iip: index in parent
1200   *
1201   * This function returns %0 on success and a negative error code on failure.
1202   */
1203  int ubifs_read_nnode(struct ubifs_info *c, struct ubifs_nnode *parent, int iip)
1204  {
1205  	struct ubifs_nbranch *branch = NULL;
1206  	struct ubifs_nnode *nnode = NULL;
1207  	void *buf = c->lpt_nod_buf;
1208  	int err, lnum, offs;
1209  
1210  	if (parent) {
1211  		branch = &parent->nbranch[iip];
1212  		lnum = branch->lnum;
1213  		offs = branch->offs;
1214  	} else {
1215  		lnum = c->lpt_lnum;
1216  		offs = c->lpt_offs;
1217  	}
1218  	nnode = kzalloc(sizeof(struct ubifs_nnode), GFP_NOFS);
1219  	if (!nnode) {
1220  		err = -ENOMEM;
1221  		goto out;
1222  	}
1223  	if (lnum == 0) {
1224  		/*
1225  		 * This nnode was not written which just means that the LEB
1226  		 * properties in the subtree below it describe empty LEBs. We
1227  		 * make the nnode as though we had read it, which in fact means
1228  		 * doing almost nothing.
1229  		 */
1230  		if (c->big_lpt)
1231  			nnode->num = calc_nnode_num_from_parent(c, parent, iip);
1232  	} else {
1233  		err = ubifs_leb_read(c, lnum, buf, offs, c->nnode_sz, 1);
1234  		if (err)
1235  			goto out;
1236  		err = ubifs_unpack_nnode(c, buf, nnode);
1237  		if (err)
1238  			goto out;
1239  	}
1240  	err = validate_nnode(c, nnode, parent, iip);
1241  	if (err)
1242  		goto out;
1243  	if (!c->big_lpt)
1244  		nnode->num = calc_nnode_num_from_parent(c, parent, iip);
1245  	if (parent) {
1246  		branch->nnode = nnode;
1247  		nnode->level = parent->level - 1;
1248  	} else {
1249  		c->nroot = nnode;
1250  		nnode->level = c->lpt_hght;
1251  	}
1252  	nnode->parent = parent;
1253  	nnode->iip = iip;
1254  	return 0;
1255  
1256  out:
1257  	ubifs_err(c, "error %d reading nnode at %d:%d", err, lnum, offs);
1258  	dump_stack();
1259  	kfree(nnode);
1260  	return err;
1261  }
1262  
1263  /**
1264   * read_pnode - read a pnode from flash and link it to the tree in memory.
1265   * @c: UBIFS file-system description object
1266   * @parent: parent nnode
1267   * @iip: index in parent
1268   *
1269   * This function returns %0 on success and a negative error code on failure.
1270   */
1271  static int read_pnode(struct ubifs_info *c, struct ubifs_nnode *parent, int iip)
1272  {
1273  	struct ubifs_nbranch *branch;
1274  	struct ubifs_pnode *pnode = NULL;
1275  	void *buf = c->lpt_nod_buf;
1276  	int err, lnum, offs;
1277  
1278  	branch = &parent->nbranch[iip];
1279  	lnum = branch->lnum;
1280  	offs = branch->offs;
1281  	pnode = kzalloc(sizeof(struct ubifs_pnode), GFP_NOFS);
1282  	if (!pnode)
1283  		return -ENOMEM;
1284  
1285  	if (lnum == 0) {
1286  		/*
1287  		 * This pnode was not written which just means that the LEB
1288  		 * properties in it describe empty LEBs. We make the pnode as
1289  		 * though we had read it.
1290  		 */
1291  		int i;
1292  
1293  		if (c->big_lpt)
1294  			pnode->num = calc_pnode_num_from_parent(c, parent, iip);
1295  		for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1296  			struct ubifs_lprops * const lprops = &pnode->lprops[i];
1297  
1298  			lprops->free = c->leb_size;
1299  			lprops->flags = ubifs_categorize_lprops(c, lprops);
1300  		}
1301  	} else {
1302  		err = ubifs_leb_read(c, lnum, buf, offs, c->pnode_sz, 1);
1303  		if (err)
1304  			goto out;
1305  		err = unpack_pnode(c, buf, pnode);
1306  		if (err)
1307  			goto out;
1308  	}
1309  	err = validate_pnode(c, pnode, parent, iip);
1310  	if (err)
1311  		goto out;
1312  	if (!c->big_lpt)
1313  		pnode->num = calc_pnode_num_from_parent(c, parent, iip);
1314  	branch->pnode = pnode;
1315  	pnode->parent = parent;
1316  	pnode->iip = iip;
1317  	set_pnode_lnum(c, pnode);
1318  	c->pnodes_have += 1;
1319  	return 0;
1320  
1321  out:
1322  	ubifs_err(c, "error %d reading pnode at %d:%d", err, lnum, offs);
1323  	ubifs_dump_pnode(c, pnode, parent, iip);
1324  	dump_stack();
1325  	ubifs_err(c, "calc num: %d", calc_pnode_num_from_parent(c, parent, iip));
1326  	kfree(pnode);
1327  	return err;
1328  }
1329  
1330  /**
1331   * read_ltab - read LPT's own lprops table.
1332   * @c: UBIFS file-system description object
1333   *
1334   * This function returns %0 on success and a negative error code on failure.
1335   */
1336  static int read_ltab(struct ubifs_info *c)
1337  {
1338  	int err;
1339  	void *buf;
1340  
1341  	buf = vmalloc(c->ltab_sz);
1342  	if (!buf)
1343  		return -ENOMEM;
1344  	err = ubifs_leb_read(c, c->ltab_lnum, buf, c->ltab_offs, c->ltab_sz, 1);
1345  	if (err)
1346  		goto out;
1347  	err = unpack_ltab(c, buf);
1348  out:
1349  	vfree(buf);
1350  	return err;
1351  }
1352  
1353  /**
1354   * read_lsave - read LPT's save table.
1355   * @c: UBIFS file-system description object
1356   *
1357   * This function returns %0 on success and a negative error code on failure.
1358   */
1359  static int read_lsave(struct ubifs_info *c)
1360  {
1361  	int err, i;
1362  	void *buf;
1363  
1364  	buf = vmalloc(c->lsave_sz);
1365  	if (!buf)
1366  		return -ENOMEM;
1367  	err = ubifs_leb_read(c, c->lsave_lnum, buf, c->lsave_offs,
1368  			     c->lsave_sz, 1);
1369  	if (err)
1370  		goto out;
1371  	err = unpack_lsave(c, buf);
1372  	if (err)
1373  		goto out;
1374  	for (i = 0; i < c->lsave_cnt; i++) {
1375  		int lnum = c->lsave[i];
1376  		struct ubifs_lprops *lprops;
1377  
1378  		/*
1379  		 * Due to automatic resizing, the values in the lsave table
1380  		 * could be beyond the volume size - just ignore them.
1381  		 */
1382  		if (lnum >= c->leb_cnt)
1383  			continue;
1384  		lprops = ubifs_lpt_lookup(c, lnum);
1385  		if (IS_ERR(lprops)) {
1386  			err = PTR_ERR(lprops);
1387  			goto out;
1388  		}
1389  	}
1390  out:
1391  	vfree(buf);
1392  	return err;
1393  }
1394  
1395  /**
1396   * ubifs_get_nnode - get a nnode.
1397   * @c: UBIFS file-system description object
1398   * @parent: parent nnode (or NULL for the root)
1399   * @iip: index in parent
1400   *
1401   * This function returns a pointer to the nnode on success or a negative error
1402   * code on failure.
1403   */
1404  struct ubifs_nnode *ubifs_get_nnode(struct ubifs_info *c,
1405  				    struct ubifs_nnode *parent, int iip)
1406  {
1407  	struct ubifs_nbranch *branch;
1408  	struct ubifs_nnode *nnode;
1409  	int err;
1410  
1411  	branch = &parent->nbranch[iip];
1412  	nnode = branch->nnode;
1413  	if (nnode)
1414  		return nnode;
1415  	err = ubifs_read_nnode(c, parent, iip);
1416  	if (err)
1417  		return ERR_PTR(err);
1418  	return branch->nnode;
1419  }
1420  
1421  /**
1422   * ubifs_get_pnode - get a pnode.
1423   * @c: UBIFS file-system description object
1424   * @parent: parent nnode
1425   * @iip: index in parent
1426   *
1427   * This function returns a pointer to the pnode on success or a negative error
1428   * code on failure.
1429   */
1430  struct ubifs_pnode *ubifs_get_pnode(struct ubifs_info *c,
1431  				    struct ubifs_nnode *parent, int iip)
1432  {
1433  	struct ubifs_nbranch *branch;
1434  	struct ubifs_pnode *pnode;
1435  	int err;
1436  
1437  	branch = &parent->nbranch[iip];
1438  	pnode = branch->pnode;
1439  	if (pnode)
1440  		return pnode;
1441  	err = read_pnode(c, parent, iip);
1442  	if (err)
1443  		return ERR_PTR(err);
1444  	update_cats(c, branch->pnode);
1445  	return branch->pnode;
1446  }
1447  
1448  /**
1449   * ubifs_pnode_lookup - lookup a pnode in the LPT.
1450   * @c: UBIFS file-system description object
1451   * @i: pnode number (0 to (main_lebs - 1) / UBIFS_LPT_FANOUT)
1452   *
1453   * This function returns a pointer to the pnode on success or a negative
1454   * error code on failure.
1455   */
1456  struct ubifs_pnode *ubifs_pnode_lookup(struct ubifs_info *c, int i)
1457  {
1458  	int err, h, iip, shft;
1459  	struct ubifs_nnode *nnode;
1460  
1461  	if (!c->nroot) {
1462  		err = ubifs_read_nnode(c, NULL, 0);
1463  		if (err)
1464  			return ERR_PTR(err);
1465  	}
1466  	i <<= UBIFS_LPT_FANOUT_SHIFT;
1467  	nnode = c->nroot;
1468  	shft = c->lpt_hght * UBIFS_LPT_FANOUT_SHIFT;
1469  	for (h = 1; h < c->lpt_hght; h++) {
1470  		iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
1471  		shft -= UBIFS_LPT_FANOUT_SHIFT;
1472  		nnode = ubifs_get_nnode(c, nnode, iip);
1473  		if (IS_ERR(nnode))
1474  			return ERR_CAST(nnode);
1475  	}
1476  	iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
1477  	return ubifs_get_pnode(c, nnode, iip);
1478  }
1479  
1480  /**
1481   * ubifs_lpt_lookup - lookup LEB properties in the LPT.
1482   * @c: UBIFS file-system description object
1483   * @lnum: LEB number to lookup
1484   *
1485   * This function returns a pointer to the LEB properties on success or a
1486   * negative error code on failure.
1487   */
1488  struct ubifs_lprops *ubifs_lpt_lookup(struct ubifs_info *c, int lnum)
1489  {
1490  	int i, iip;
1491  	struct ubifs_pnode *pnode;
1492  
1493  	i = lnum - c->main_first;
1494  	pnode = ubifs_pnode_lookup(c, i >> UBIFS_LPT_FANOUT_SHIFT);
1495  	if (IS_ERR(pnode))
1496  		return ERR_CAST(pnode);
1497  	iip = (i & (UBIFS_LPT_FANOUT - 1));
1498  	dbg_lp("LEB %d, free %d, dirty %d, flags %d", lnum,
1499  	       pnode->lprops[iip].free, pnode->lprops[iip].dirty,
1500  	       pnode->lprops[iip].flags);
1501  	return &pnode->lprops[iip];
1502  }
1503  
1504  /**
1505   * dirty_cow_nnode - ensure a nnode is not being committed.
1506   * @c: UBIFS file-system description object
1507   * @nnode: nnode to check
1508   *
1509   * Returns dirtied nnode on success or negative error code on failure.
1510   */
1511  static struct ubifs_nnode *dirty_cow_nnode(struct ubifs_info *c,
1512  					   struct ubifs_nnode *nnode)
1513  {
1514  	struct ubifs_nnode *n;
1515  	int i;
1516  
1517  	if (!test_bit(COW_CNODE, &nnode->flags)) {
1518  		/* nnode is not being committed */
1519  		if (!test_and_set_bit(DIRTY_CNODE, &nnode->flags)) {
1520  			c->dirty_nn_cnt += 1;
1521  			ubifs_add_nnode_dirt(c, nnode);
1522  		}
1523  		return nnode;
1524  	}
1525  
1526  	/* nnode is being committed, so copy it */
1527  	n = kmemdup(nnode, sizeof(struct ubifs_nnode), GFP_NOFS);
1528  	if (unlikely(!n))
1529  		return ERR_PTR(-ENOMEM);
1530  
1531  	n->cnext = NULL;
1532  	__set_bit(DIRTY_CNODE, &n->flags);
1533  	__clear_bit(COW_CNODE, &n->flags);
1534  
1535  	/* The children now have new parent */
1536  	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1537  		struct ubifs_nbranch *branch = &n->nbranch[i];
1538  
1539  		if (branch->cnode)
1540  			branch->cnode->parent = n;
1541  	}
1542  
1543  	ubifs_assert(c, !test_bit(OBSOLETE_CNODE, &nnode->flags));
1544  	__set_bit(OBSOLETE_CNODE, &nnode->flags);
1545  
1546  	c->dirty_nn_cnt += 1;
1547  	ubifs_add_nnode_dirt(c, nnode);
1548  	if (nnode->parent)
1549  		nnode->parent->nbranch[n->iip].nnode = n;
1550  	else
1551  		c->nroot = n;
1552  	return n;
1553  }
1554  
1555  /**
1556   * dirty_cow_pnode - ensure a pnode is not being committed.
1557   * @c: UBIFS file-system description object
1558   * @pnode: pnode to check
1559   *
1560   * Returns dirtied pnode on success or negative error code on failure.
1561   */
1562  static struct ubifs_pnode *dirty_cow_pnode(struct ubifs_info *c,
1563  					   struct ubifs_pnode *pnode)
1564  {
1565  	struct ubifs_pnode *p;
1566  
1567  	if (!test_bit(COW_CNODE, &pnode->flags)) {
1568  		/* pnode is not being committed */
1569  		if (!test_and_set_bit(DIRTY_CNODE, &pnode->flags)) {
1570  			c->dirty_pn_cnt += 1;
1571  			add_pnode_dirt(c, pnode);
1572  		}
1573  		return pnode;
1574  	}
1575  
1576  	/* pnode is being committed, so copy it */
1577  	p = kmemdup(pnode, sizeof(struct ubifs_pnode), GFP_NOFS);
1578  	if (unlikely(!p))
1579  		return ERR_PTR(-ENOMEM);
1580  
1581  	p->cnext = NULL;
1582  	__set_bit(DIRTY_CNODE, &p->flags);
1583  	__clear_bit(COW_CNODE, &p->flags);
1584  	replace_cats(c, pnode, p);
1585  
1586  	ubifs_assert(c, !test_bit(OBSOLETE_CNODE, &pnode->flags));
1587  	__set_bit(OBSOLETE_CNODE, &pnode->flags);
1588  
1589  	c->dirty_pn_cnt += 1;
1590  	add_pnode_dirt(c, pnode);
1591  	pnode->parent->nbranch[p->iip].pnode = p;
1592  	return p;
1593  }
1594  
1595  /**
1596   * ubifs_lpt_lookup_dirty - lookup LEB properties in the LPT.
1597   * @c: UBIFS file-system description object
1598   * @lnum: LEB number to lookup
1599   *
1600   * This function returns a pointer to the LEB properties on success or a
1601   * negative error code on failure.
1602   */
1603  struct ubifs_lprops *ubifs_lpt_lookup_dirty(struct ubifs_info *c, int lnum)
1604  {
1605  	int err, i, h, iip, shft;
1606  	struct ubifs_nnode *nnode;
1607  	struct ubifs_pnode *pnode;
1608  
1609  	if (!c->nroot) {
1610  		err = ubifs_read_nnode(c, NULL, 0);
1611  		if (err)
1612  			return ERR_PTR(err);
1613  	}
1614  	nnode = c->nroot;
1615  	nnode = dirty_cow_nnode(c, nnode);
1616  	if (IS_ERR(nnode))
1617  		return ERR_CAST(nnode);
1618  	i = lnum - c->main_first;
1619  	shft = c->lpt_hght * UBIFS_LPT_FANOUT_SHIFT;
1620  	for (h = 1; h < c->lpt_hght; h++) {
1621  		iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
1622  		shft -= UBIFS_LPT_FANOUT_SHIFT;
1623  		nnode = ubifs_get_nnode(c, nnode, iip);
1624  		if (IS_ERR(nnode))
1625  			return ERR_CAST(nnode);
1626  		nnode = dirty_cow_nnode(c, nnode);
1627  		if (IS_ERR(nnode))
1628  			return ERR_CAST(nnode);
1629  	}
1630  	iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
1631  	pnode = ubifs_get_pnode(c, nnode, iip);
1632  	if (IS_ERR(pnode))
1633  		return ERR_CAST(pnode);
1634  	pnode = dirty_cow_pnode(c, pnode);
1635  	if (IS_ERR(pnode))
1636  		return ERR_CAST(pnode);
1637  	iip = (i & (UBIFS_LPT_FANOUT - 1));
1638  	dbg_lp("LEB %d, free %d, dirty %d, flags %d", lnum,
1639  	       pnode->lprops[iip].free, pnode->lprops[iip].dirty,
1640  	       pnode->lprops[iip].flags);
1641  	ubifs_assert(c, test_bit(DIRTY_CNODE, &pnode->flags));
1642  	return &pnode->lprops[iip];
1643  }
1644  
1645  /**
1646   * ubifs_lpt_calc_hash - Calculate hash of the LPT pnodes
1647   * @c: UBIFS file-system description object
1648   * @hash: the returned hash of the LPT pnodes
1649   *
1650   * This function iterates over the LPT pnodes and creates a hash over them.
1651   * Returns 0 for success or a negative error code otherwise.
1652   */
1653  int ubifs_lpt_calc_hash(struct ubifs_info *c, u8 *hash)
1654  {
1655  	struct ubifs_nnode *nnode, *nn;
1656  	struct ubifs_cnode *cnode;
1657  	struct shash_desc *desc;
1658  	int iip = 0, i;
1659  	int bufsiz = max_t(int, c->nnode_sz, c->pnode_sz);
1660  	void *buf;
1661  	int err;
1662  
1663  	if (!ubifs_authenticated(c))
1664  		return 0;
1665  
1666  	if (!c->nroot) {
1667  		err = ubifs_read_nnode(c, NULL, 0);
1668  		if (err)
1669  			return err;
1670  	}
1671  
1672  	desc = ubifs_hash_get_desc(c);
1673  	if (IS_ERR(desc))
1674  		return PTR_ERR(desc);
1675  
1676  	buf = kmalloc(bufsiz, GFP_NOFS);
1677  	if (!buf) {
1678  		err = -ENOMEM;
1679  		goto out;
1680  	}
1681  
1682  	cnode = (struct ubifs_cnode *)c->nroot;
1683  
1684  	while (cnode) {
1685  		nnode = cnode->parent;
1686  		nn = (struct ubifs_nnode *)cnode;
1687  		if (cnode->level > 1) {
1688  			while (iip < UBIFS_LPT_FANOUT) {
1689  				if (nn->nbranch[iip].lnum == 0) {
1690  					/* Go right */
1691  					iip++;
1692  					continue;
1693  				}
1694  
1695  				nnode = ubifs_get_nnode(c, nn, iip);
1696  				if (IS_ERR(nnode)) {
1697  					err = PTR_ERR(nnode);
1698  					goto out;
1699  				}
1700  
1701  				/* Go down */
1702  				iip = 0;
1703  				cnode = (struct ubifs_cnode *)nnode;
1704  				break;
1705  			}
1706  			if (iip < UBIFS_LPT_FANOUT)
1707  				continue;
1708  		} else {
1709  			struct ubifs_pnode *pnode;
1710  
1711  			for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1712  				if (nn->nbranch[i].lnum == 0)
1713  					continue;
1714  				pnode = ubifs_get_pnode(c, nn, i);
1715  				if (IS_ERR(pnode)) {
1716  					err = PTR_ERR(pnode);
1717  					goto out;
1718  				}
1719  
1720  				ubifs_pack_pnode(c, buf, pnode);
1721  				err = ubifs_shash_update(c, desc, buf,
1722  							 c->pnode_sz);
1723  				if (err)
1724  					goto out;
1725  			}
1726  		}
1727  		/* Go up and to the right */
1728  		iip = cnode->iip + 1;
1729  		cnode = (struct ubifs_cnode *)nnode;
1730  	}
1731  
1732  	err = ubifs_shash_final(c, desc, hash);
1733  out:
1734  	kfree(desc);
1735  	kfree(buf);
1736  
1737  	return err;
1738  }
1739  
1740  /**
1741   * lpt_check_hash - check the hash of the LPT.
1742   * @c: UBIFS file-system description object
1743   *
1744   * This function calculates a hash over all pnodes in the LPT and compares it with
1745   * the hash stored in the master node. Returns %0 on success and a negative error
1746   * code on failure.
1747   */
1748  static int lpt_check_hash(struct ubifs_info *c)
1749  {
1750  	int err;
1751  	u8 hash[UBIFS_HASH_ARR_SZ];
1752  
1753  	if (!ubifs_authenticated(c))
1754  		return 0;
1755  
1756  	err = ubifs_lpt_calc_hash(c, hash);
1757  	if (err)
1758  		return err;
1759  
1760  	if (ubifs_check_hash(c, c->mst_node->hash_lpt, hash)) {
1761  		err = -EPERM;
1762  		ubifs_err(c, "Failed to authenticate LPT");
1763  	} else {
1764  		err = 0;
1765  	}
1766  
1767  	return err;
1768  }
1769  
1770  /**
1771   * lpt_init_rd - initialize the LPT for reading.
1772   * @c: UBIFS file-system description object
1773   *
1774   * This function returns %0 on success and a negative error code on failure.
1775   */
1776  static int lpt_init_rd(struct ubifs_info *c)
1777  {
1778  	int err, i;
1779  
1780  	c->ltab = vmalloc(array_size(sizeof(struct ubifs_lpt_lprops),
1781  				     c->lpt_lebs));
1782  	if (!c->ltab)
1783  		return -ENOMEM;
1784  
1785  	i = max_t(int, c->nnode_sz, c->pnode_sz);
1786  	c->lpt_nod_buf = kmalloc(i, GFP_KERNEL);
1787  	if (!c->lpt_nod_buf)
1788  		return -ENOMEM;
1789  
1790  	for (i = 0; i < LPROPS_HEAP_CNT; i++) {
1791  		c->lpt_heap[i].arr = kmalloc_array(LPT_HEAP_SZ,
1792  						   sizeof(void *),
1793  						   GFP_KERNEL);
1794  		if (!c->lpt_heap[i].arr)
1795  			return -ENOMEM;
1796  		c->lpt_heap[i].cnt = 0;
1797  		c->lpt_heap[i].max_cnt = LPT_HEAP_SZ;
1798  	}
1799  
1800  	c->dirty_idx.arr = kmalloc_array(LPT_HEAP_SZ, sizeof(void *),
1801  					 GFP_KERNEL);
1802  	if (!c->dirty_idx.arr)
1803  		return -ENOMEM;
1804  	c->dirty_idx.cnt = 0;
1805  	c->dirty_idx.max_cnt = LPT_HEAP_SZ;
1806  
1807  	err = read_ltab(c);
1808  	if (err)
1809  		return err;
1810  
1811  	err = lpt_check_hash(c);
1812  	if (err)
1813  		return err;
1814  
1815  	dbg_lp("space_bits %d", c->space_bits);
1816  	dbg_lp("lpt_lnum_bits %d", c->lpt_lnum_bits);
1817  	dbg_lp("lpt_offs_bits %d", c->lpt_offs_bits);
1818  	dbg_lp("lpt_spc_bits %d", c->lpt_spc_bits);
1819  	dbg_lp("pcnt_bits %d", c->pcnt_bits);
1820  	dbg_lp("lnum_bits %d", c->lnum_bits);
1821  	dbg_lp("pnode_sz %d", c->pnode_sz);
1822  	dbg_lp("nnode_sz %d", c->nnode_sz);
1823  	dbg_lp("ltab_sz %d", c->ltab_sz);
1824  	dbg_lp("lsave_sz %d", c->lsave_sz);
1825  	dbg_lp("lsave_cnt %d", c->lsave_cnt);
1826  	dbg_lp("lpt_hght %d", c->lpt_hght);
1827  	dbg_lp("big_lpt %u", c->big_lpt);
1828  	dbg_lp("LPT root is at %d:%d", c->lpt_lnum, c->lpt_offs);
1829  	dbg_lp("LPT head is at %d:%d", c->nhead_lnum, c->nhead_offs);
1830  	dbg_lp("LPT ltab is at %d:%d", c->ltab_lnum, c->ltab_offs);
1831  	if (c->big_lpt)
1832  		dbg_lp("LPT lsave is at %d:%d", c->lsave_lnum, c->lsave_offs);
1833  
1834  	return 0;
1835  }
1836  
1837  /**
1838   * lpt_init_wr - initialize the LPT for writing.
1839   * @c: UBIFS file-system description object
1840   *
1841   * 'lpt_init_rd()' must have been called already.
1842   *
1843   * This function returns %0 on success and a negative error code on failure.
1844   */
1845  static int lpt_init_wr(struct ubifs_info *c)
1846  {
1847  	int err, i;
1848  
1849  	c->ltab_cmt = vmalloc(array_size(sizeof(struct ubifs_lpt_lprops),
1850  					 c->lpt_lebs));
1851  	if (!c->ltab_cmt)
1852  		return -ENOMEM;
1853  
1854  	c->lpt_buf = vmalloc(c->leb_size);
1855  	if (!c->lpt_buf)
1856  		return -ENOMEM;
1857  
1858  	if (c->big_lpt) {
1859  		c->lsave = kmalloc_array(c->lsave_cnt, sizeof(int), GFP_NOFS);
1860  		if (!c->lsave)
1861  			return -ENOMEM;
1862  		err = read_lsave(c);
1863  		if (err)
1864  			return err;
1865  	}
1866  
1867  	for (i = 0; i < c->lpt_lebs; i++)
1868  		if (c->ltab[i].free == c->leb_size) {
1869  			err = ubifs_leb_unmap(c, i + c->lpt_first);
1870  			if (err)
1871  				return err;
1872  		}
1873  
1874  	return 0;
1875  }
1876  
1877  /**
1878   * ubifs_lpt_init - initialize the LPT.
1879   * @c: UBIFS file-system description object
1880   * @rd: whether to initialize lpt for reading
1881   * @wr: whether to initialize lpt for writing
1882   *
1883   * For mounting 'rw', @rd and @wr are both true. For mounting 'ro', @rd is true
1884   * and @wr is false. For mounting from 'ro' to 'rw', @rd is false and @wr is
1885   * true.
1886   *
1887   * This function returns %0 on success and a negative error code on failure.
1888   */
1889  int ubifs_lpt_init(struct ubifs_info *c, int rd, int wr)
1890  {
1891  	int err;
1892  
1893  	if (rd) {
1894  		err = lpt_init_rd(c);
1895  		if (err)
1896  			goto out_err;
1897  	}
1898  
1899  	if (wr) {
1900  		err = lpt_init_wr(c);
1901  		if (err)
1902  			goto out_err;
1903  	}
1904  
1905  	return 0;
1906  
1907  out_err:
1908  	if (wr)
1909  		ubifs_lpt_free(c, 1);
1910  	if (rd)
1911  		ubifs_lpt_free(c, 0);
1912  	return err;
1913  }
1914  
1915  /**
1916   * struct lpt_scan_node - somewhere to put nodes while we scan LPT.
1917   * @nnode: where to keep a nnode
1918   * @pnode: where to keep a pnode
1919   * @cnode: where to keep a cnode
1920   * @in_tree: is the node in the tree in memory
1921   * @ptr.nnode: pointer to the nnode (if it is an nnode) which may be here or in
1922   * the tree
1923   * @ptr.pnode: ditto for pnode
1924   * @ptr.cnode: ditto for cnode
1925   */
1926  struct lpt_scan_node {
1927  	union {
1928  		struct ubifs_nnode nnode;
1929  		struct ubifs_pnode pnode;
1930  		struct ubifs_cnode cnode;
1931  	};
1932  	int in_tree;
1933  	union {
1934  		struct ubifs_nnode *nnode;
1935  		struct ubifs_pnode *pnode;
1936  		struct ubifs_cnode *cnode;
1937  	} ptr;
1938  };
1939  
1940  /**
1941   * scan_get_nnode - for the scan, get a nnode from either the tree or flash.
1942   * @c: the UBIFS file-system description object
1943   * @path: where to put the nnode
1944   * @parent: parent of the nnode
1945   * @iip: index in parent of the nnode
1946   *
1947   * This function returns a pointer to the nnode on success or a negative error
1948   * code on failure.
1949   */
1950  static struct ubifs_nnode *scan_get_nnode(struct ubifs_info *c,
1951  					  struct lpt_scan_node *path,
1952  					  struct ubifs_nnode *parent, int iip)
1953  {
1954  	struct ubifs_nbranch *branch;
1955  	struct ubifs_nnode *nnode;
1956  	void *buf = c->lpt_nod_buf;
1957  	int err;
1958  
1959  	branch = &parent->nbranch[iip];
1960  	nnode = branch->nnode;
1961  	if (nnode) {
1962  		path->in_tree = 1;
1963  		path->ptr.nnode = nnode;
1964  		return nnode;
1965  	}
1966  	nnode = &path->nnode;
1967  	path->in_tree = 0;
1968  	path->ptr.nnode = nnode;
1969  	memset(nnode, 0, sizeof(struct ubifs_nnode));
1970  	if (branch->lnum == 0) {
1971  		/*
1972  		 * This nnode was not written which just means that the LEB
1973  		 * properties in the subtree below it describe empty LEBs. We
1974  		 * make the nnode as though we had read it, which in fact means
1975  		 * doing almost nothing.
1976  		 */
1977  		if (c->big_lpt)
1978  			nnode->num = calc_nnode_num_from_parent(c, parent, iip);
1979  	} else {
1980  		err = ubifs_leb_read(c, branch->lnum, buf, branch->offs,
1981  				     c->nnode_sz, 1);
1982  		if (err)
1983  			return ERR_PTR(err);
1984  		err = ubifs_unpack_nnode(c, buf, nnode);
1985  		if (err)
1986  			return ERR_PTR(err);
1987  	}
1988  	err = validate_nnode(c, nnode, parent, iip);
1989  	if (err)
1990  		return ERR_PTR(err);
1991  	if (!c->big_lpt)
1992  		nnode->num = calc_nnode_num_from_parent(c, parent, iip);
1993  	nnode->level = parent->level - 1;
1994  	nnode->parent = parent;
1995  	nnode->iip = iip;
1996  	return nnode;
1997  }
1998  
1999  /**
2000   * scan_get_pnode - for the scan, get a pnode from either the tree or flash.
2001   * @c: the UBIFS file-system description object
2002   * @path: where to put the pnode
2003   * @parent: parent of the pnode
2004   * @iip: index in parent of the pnode
2005   *
2006   * This function returns a pointer to the pnode on success or a negative error
2007   * code on failure.
2008   */
2009  static struct ubifs_pnode *scan_get_pnode(struct ubifs_info *c,
2010  					  struct lpt_scan_node *path,
2011  					  struct ubifs_nnode *parent, int iip)
2012  {
2013  	struct ubifs_nbranch *branch;
2014  	struct ubifs_pnode *pnode;
2015  	void *buf = c->lpt_nod_buf;
2016  	int err;
2017  
2018  	branch = &parent->nbranch[iip];
2019  	pnode = branch->pnode;
2020  	if (pnode) {
2021  		path->in_tree = 1;
2022  		path->ptr.pnode = pnode;
2023  		return pnode;
2024  	}
2025  	pnode = &path->pnode;
2026  	path->in_tree = 0;
2027  	path->ptr.pnode = pnode;
2028  	memset(pnode, 0, sizeof(struct ubifs_pnode));
2029  	if (branch->lnum == 0) {
2030  		/*
2031  		 * This pnode was not written which just means that the LEB
2032  		 * properties in it describe empty LEBs. We make the pnode as
2033  		 * though we had read it.
2034  		 */
2035  		int i;
2036  
2037  		if (c->big_lpt)
2038  			pnode->num = calc_pnode_num_from_parent(c, parent, iip);
2039  		for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
2040  			struct ubifs_lprops * const lprops = &pnode->lprops[i];
2041  
2042  			lprops->free = c->leb_size;
2043  			lprops->flags = ubifs_categorize_lprops(c, lprops);
2044  		}
2045  	} else {
2046  		ubifs_assert(c, branch->lnum >= c->lpt_first &&
2047  			     branch->lnum <= c->lpt_last);
2048  		ubifs_assert(c, branch->offs >= 0 && branch->offs < c->leb_size);
2049  		err = ubifs_leb_read(c, branch->lnum, buf, branch->offs,
2050  				     c->pnode_sz, 1);
2051  		if (err)
2052  			return ERR_PTR(err);
2053  		err = unpack_pnode(c, buf, pnode);
2054  		if (err)
2055  			return ERR_PTR(err);
2056  	}
2057  	err = validate_pnode(c, pnode, parent, iip);
2058  	if (err)
2059  		return ERR_PTR(err);
2060  	if (!c->big_lpt)
2061  		pnode->num = calc_pnode_num_from_parent(c, parent, iip);
2062  	pnode->parent = parent;
2063  	pnode->iip = iip;
2064  	set_pnode_lnum(c, pnode);
2065  	return pnode;
2066  }
2067  
2068  /**
2069   * ubifs_lpt_scan_nolock - scan the LPT.
2070   * @c: the UBIFS file-system description object
2071   * @start_lnum: LEB number from which to start scanning
2072   * @end_lnum: LEB number at which to stop scanning
2073   * @scan_cb: callback function called for each lprops
2074   * @data: data to be passed to the callback function
2075   *
2076   * This function returns %0 on success and a negative error code on failure.
2077   */
2078  int ubifs_lpt_scan_nolock(struct ubifs_info *c, int start_lnum, int end_lnum,
2079  			  ubifs_lpt_scan_callback scan_cb, void *data)
2080  {
2081  	int err = 0, i, h, iip, shft;
2082  	struct ubifs_nnode *nnode;
2083  	struct ubifs_pnode *pnode;
2084  	struct lpt_scan_node *path;
2085  
2086  	if (start_lnum == -1) {
2087  		start_lnum = end_lnum + 1;
2088  		if (start_lnum >= c->leb_cnt)
2089  			start_lnum = c->main_first;
2090  	}
2091  
2092  	ubifs_assert(c, start_lnum >= c->main_first && start_lnum < c->leb_cnt);
2093  	ubifs_assert(c, end_lnum >= c->main_first && end_lnum < c->leb_cnt);
2094  
2095  	if (!c->nroot) {
2096  		err = ubifs_read_nnode(c, NULL, 0);
2097  		if (err)
2098  			return err;
2099  	}
2100  
2101  	path = kmalloc_array(c->lpt_hght + 1, sizeof(struct lpt_scan_node),
2102  			     GFP_NOFS);
2103  	if (!path)
2104  		return -ENOMEM;
2105  
2106  	path[0].ptr.nnode = c->nroot;
2107  	path[0].in_tree = 1;
2108  again:
2109  	/* Descend to the pnode containing start_lnum */
2110  	nnode = c->nroot;
2111  	i = start_lnum - c->main_first;
2112  	shft = c->lpt_hght * UBIFS_LPT_FANOUT_SHIFT;
2113  	for (h = 1; h < c->lpt_hght; h++) {
2114  		iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
2115  		shft -= UBIFS_LPT_FANOUT_SHIFT;
2116  		nnode = scan_get_nnode(c, path + h, nnode, iip);
2117  		if (IS_ERR(nnode)) {
2118  			err = PTR_ERR(nnode);
2119  			goto out;
2120  		}
2121  	}
2122  	iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
2123  	pnode = scan_get_pnode(c, path + h, nnode, iip);
2124  	if (IS_ERR(pnode)) {
2125  		err = PTR_ERR(pnode);
2126  		goto out;
2127  	}
2128  	iip = (i & (UBIFS_LPT_FANOUT - 1));
2129  
2130  	/* Loop for each lprops */
2131  	while (1) {
2132  		struct ubifs_lprops *lprops = &pnode->lprops[iip];
2133  		int ret, lnum = lprops->lnum;
2134  
2135  		ret = scan_cb(c, lprops, path[h].in_tree, data);
2136  		if (ret < 0) {
2137  			err = ret;
2138  			goto out;
2139  		}
2140  		if (ret & LPT_SCAN_ADD) {
2141  			/* Add all the nodes in path to the tree in memory */
2142  			for (h = 1; h < c->lpt_hght; h++) {
2143  				const size_t sz = sizeof(struct ubifs_nnode);
2144  				struct ubifs_nnode *parent;
2145  
2146  				if (path[h].in_tree)
2147  					continue;
2148  				nnode = kmemdup(&path[h].nnode, sz, GFP_NOFS);
2149  				if (!nnode) {
2150  					err = -ENOMEM;
2151  					goto out;
2152  				}
2153  				parent = nnode->parent;
2154  				parent->nbranch[nnode->iip].nnode = nnode;
2155  				path[h].ptr.nnode = nnode;
2156  				path[h].in_tree = 1;
2157  				path[h + 1].cnode.parent = nnode;
2158  			}
2159  			if (path[h].in_tree)
2160  				ubifs_ensure_cat(c, lprops);
2161  			else {
2162  				const size_t sz = sizeof(struct ubifs_pnode);
2163  				struct ubifs_nnode *parent;
2164  
2165  				pnode = kmemdup(&path[h].pnode, sz, GFP_NOFS);
2166  				if (!pnode) {
2167  					err = -ENOMEM;
2168  					goto out;
2169  				}
2170  				parent = pnode->parent;
2171  				parent->nbranch[pnode->iip].pnode = pnode;
2172  				path[h].ptr.pnode = pnode;
2173  				path[h].in_tree = 1;
2174  				update_cats(c, pnode);
2175  				c->pnodes_have += 1;
2176  			}
2177  			err = dbg_check_lpt_nodes(c, (struct ubifs_cnode *)
2178  						  c->nroot, 0, 0);
2179  			if (err)
2180  				goto out;
2181  			err = dbg_check_cats(c);
2182  			if (err)
2183  				goto out;
2184  		}
2185  		if (ret & LPT_SCAN_STOP) {
2186  			err = 0;
2187  			break;
2188  		}
2189  		/* Get the next lprops */
2190  		if (lnum == end_lnum) {
2191  			/*
2192  			 * We got to the end without finding what we were
2193  			 * looking for
2194  			 */
2195  			err = -ENOSPC;
2196  			goto out;
2197  		}
2198  		if (lnum + 1 >= c->leb_cnt) {
2199  			/* Wrap-around to the beginning */
2200  			start_lnum = c->main_first;
2201  			goto again;
2202  		}
2203  		if (iip + 1 < UBIFS_LPT_FANOUT) {
2204  			/* Next lprops is in the same pnode */
2205  			iip += 1;
2206  			continue;
2207  		}
2208  		/* We need to get the next pnode. Go up until we can go right */
2209  		iip = pnode->iip;
2210  		while (1) {
2211  			h -= 1;
2212  			ubifs_assert(c, h >= 0);
2213  			nnode = path[h].ptr.nnode;
2214  			if (iip + 1 < UBIFS_LPT_FANOUT)
2215  				break;
2216  			iip = nnode->iip;
2217  		}
2218  		/* Go right */
2219  		iip += 1;
2220  		/* Descend to the pnode */
2221  		h += 1;
2222  		for (; h < c->lpt_hght; h++) {
2223  			nnode = scan_get_nnode(c, path + h, nnode, iip);
2224  			if (IS_ERR(nnode)) {
2225  				err = PTR_ERR(nnode);
2226  				goto out;
2227  			}
2228  			iip = 0;
2229  		}
2230  		pnode = scan_get_pnode(c, path + h, nnode, iip);
2231  		if (IS_ERR(pnode)) {
2232  			err = PTR_ERR(pnode);
2233  			goto out;
2234  		}
2235  		iip = 0;
2236  	}
2237  out:
2238  	kfree(path);
2239  	return err;
2240  }
2241  
2242  /**
2243   * dbg_chk_pnode - check a pnode.
2244   * @c: the UBIFS file-system description object
2245   * @pnode: pnode to check
2246   * @col: pnode column
2247   *
2248   * This function returns %0 on success and a negative error code on failure.
2249   */
2250  static int dbg_chk_pnode(struct ubifs_info *c, struct ubifs_pnode *pnode,
2251  			 int col)
2252  {
2253  	int i;
2254  
2255  	if (pnode->num != col) {
2256  		ubifs_err(c, "pnode num %d expected %d parent num %d iip %d",
2257  			  pnode->num, col, pnode->parent->num, pnode->iip);
2258  		return -EINVAL;
2259  	}
2260  	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
2261  		struct ubifs_lprops *lp, *lprops = &pnode->lprops[i];
2262  		int lnum = (pnode->num << UBIFS_LPT_FANOUT_SHIFT) + i +
2263  			   c->main_first;
2264  		int found, cat = lprops->flags & LPROPS_CAT_MASK;
2265  		struct ubifs_lpt_heap *heap;
2266  		struct list_head *list = NULL;
2267  
2268  		if (lnum >= c->leb_cnt)
2269  			continue;
2270  		if (lprops->lnum != lnum) {
2271  			ubifs_err(c, "bad LEB number %d expected %d",
2272  				  lprops->lnum, lnum);
2273  			return -EINVAL;
2274  		}
2275  		if (lprops->flags & LPROPS_TAKEN) {
2276  			if (cat != LPROPS_UNCAT) {
2277  				ubifs_err(c, "LEB %d taken but not uncat %d",
2278  					  lprops->lnum, cat);
2279  				return -EINVAL;
2280  			}
2281  			continue;
2282  		}
2283  		if (lprops->flags & LPROPS_INDEX) {
2284  			switch (cat) {
2285  			case LPROPS_UNCAT:
2286  			case LPROPS_DIRTY_IDX:
2287  			case LPROPS_FRDI_IDX:
2288  				break;
2289  			default:
2290  				ubifs_err(c, "LEB %d index but cat %d",
2291  					  lprops->lnum, cat);
2292  				return -EINVAL;
2293  			}
2294  		} else {
2295  			switch (cat) {
2296  			case LPROPS_UNCAT:
2297  			case LPROPS_DIRTY:
2298  			case LPROPS_FREE:
2299  			case LPROPS_EMPTY:
2300  			case LPROPS_FREEABLE:
2301  				break;
2302  			default:
2303  				ubifs_err(c, "LEB %d not index but cat %d",
2304  					  lprops->lnum, cat);
2305  				return -EINVAL;
2306  			}
2307  		}
2308  		switch (cat) {
2309  		case LPROPS_UNCAT:
2310  			list = &c->uncat_list;
2311  			break;
2312  		case LPROPS_EMPTY:
2313  			list = &c->empty_list;
2314  			break;
2315  		case LPROPS_FREEABLE:
2316  			list = &c->freeable_list;
2317  			break;
2318  		case LPROPS_FRDI_IDX:
2319  			list = &c->frdi_idx_list;
2320  			break;
2321  		}
2322  		found = 0;
2323  		switch (cat) {
2324  		case LPROPS_DIRTY:
2325  		case LPROPS_DIRTY_IDX:
2326  		case LPROPS_FREE:
2327  			heap = &c->lpt_heap[cat - 1];
2328  			if (lprops->hpos < heap->cnt &&
2329  			    heap->arr[lprops->hpos] == lprops)
2330  				found = 1;
2331  			break;
2332  		case LPROPS_UNCAT:
2333  		case LPROPS_EMPTY:
2334  		case LPROPS_FREEABLE:
2335  		case LPROPS_FRDI_IDX:
2336  			list_for_each_entry(lp, list, list)
2337  				if (lprops == lp) {
2338  					found = 1;
2339  					break;
2340  				}
2341  			break;
2342  		}
2343  		if (!found) {
2344  			ubifs_err(c, "LEB %d cat %d not found in cat heap/list",
2345  				  lprops->lnum, cat);
2346  			return -EINVAL;
2347  		}
2348  		switch (cat) {
2349  		case LPROPS_EMPTY:
2350  			if (lprops->free != c->leb_size) {
2351  				ubifs_err(c, "LEB %d cat %d free %d dirty %d",
2352  					  lprops->lnum, cat, lprops->free,
2353  					  lprops->dirty);
2354  				return -EINVAL;
2355  			}
2356  			break;
2357  		case LPROPS_FREEABLE:
2358  		case LPROPS_FRDI_IDX:
2359  			if (lprops->free + lprops->dirty != c->leb_size) {
2360  				ubifs_err(c, "LEB %d cat %d free %d dirty %d",
2361  					  lprops->lnum, cat, lprops->free,
2362  					  lprops->dirty);
2363  				return -EINVAL;
2364  			}
2365  			break;
2366  		}
2367  	}
2368  	return 0;
2369  }
2370  
2371  /**
2372   * dbg_check_lpt_nodes - check nnodes and pnodes.
2373   * @c: the UBIFS file-system description object
2374   * @cnode: next cnode (nnode or pnode) to check
2375   * @row: row of cnode (root is zero)
2376   * @col: column of cnode (leftmost is zero)
2377   *
2378   * This function returns %0 on success and a negative error code on failure.
2379   */
2380  int dbg_check_lpt_nodes(struct ubifs_info *c, struct ubifs_cnode *cnode,
2381  			int row, int col)
2382  {
2383  	struct ubifs_nnode *nnode, *nn;
2384  	struct ubifs_cnode *cn;
2385  	int num, iip = 0, err;
2386  
2387  	if (!dbg_is_chk_lprops(c))
2388  		return 0;
2389  
2390  	while (cnode) {
2391  		ubifs_assert(c, row >= 0);
2392  		nnode = cnode->parent;
2393  		if (cnode->level) {
2394  			/* cnode is a nnode */
2395  			num = calc_nnode_num(row, col);
2396  			if (cnode->num != num) {
2397  				ubifs_err(c, "nnode num %d expected %d parent num %d iip %d",
2398  					  cnode->num, num,
2399  					  (nnode ? nnode->num : 0), cnode->iip);
2400  				return -EINVAL;
2401  			}
2402  			nn = (struct ubifs_nnode *)cnode;
2403  			while (iip < UBIFS_LPT_FANOUT) {
2404  				cn = nn->nbranch[iip].cnode;
2405  				if (cn) {
2406  					/* Go down */
2407  					row += 1;
2408  					col <<= UBIFS_LPT_FANOUT_SHIFT;
2409  					col += iip;
2410  					iip = 0;
2411  					cnode = cn;
2412  					break;
2413  				}
2414  				/* Go right */
2415  				iip += 1;
2416  			}
2417  			if (iip < UBIFS_LPT_FANOUT)
2418  				continue;
2419  		} else {
2420  			struct ubifs_pnode *pnode;
2421  
2422  			/* cnode is a pnode */
2423  			pnode = (struct ubifs_pnode *)cnode;
2424  			err = dbg_chk_pnode(c, pnode, col);
2425  			if (err)
2426  				return err;
2427  		}
2428  		/* Go up and to the right */
2429  		row -= 1;
2430  		col >>= UBIFS_LPT_FANOUT_SHIFT;
2431  		iip = cnode->iip + 1;
2432  		cnode = (struct ubifs_cnode *)nnode;
2433  	}
2434  	return 0;
2435  }
2436