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TOMOYO Linux Cross Reference
Linux/fs/ubifs/lpt.c

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  1 /*
  2  * This file is part of UBIFS.
  3  *
  4  * Copyright (C) 2006-2008 Nokia Corporation.
  5  *
  6  * This program is free software; you can redistribute it and/or modify it
  7  * under the terms of the GNU General Public License version 2 as published by
  8  * the Free Software Foundation.
  9  *
 10  * This program is distributed in the hope that it will be useful, but WITHOUT
 11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 13  * more details.
 14  *
 15  * You should have received a copy of the GNU General Public License along with
 16  * this program; if not, write to the Free Software Foundation, Inc., 51
 17  * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 18  *
 19  * Authors: Adrian Hunter
 20  *          Artem Bityutskiy (Битюцкий Артём)
 21  */
 22 
 23 /*
 24  * This file implements the LEB properties tree (LPT) area. The LPT area
 25  * contains the LEB properties tree, a table of LPT area eraseblocks (ltab), and
 26  * (for the "big" model) a table of saved LEB numbers (lsave). The LPT area sits
 27  * between the log and the orphan area.
 28  *
 29  * The LPT area is like a miniature self-contained file system. It is required
 30  * that it never runs out of space, is fast to access and update, and scales
 31  * logarithmically. The LEB properties tree is implemented as a wandering tree
 32  * much like the TNC, and the LPT area has its own garbage collection.
 33  *
 34  * The LPT has two slightly different forms called the "small model" and the
 35  * "big model". The small model is used when the entire LEB properties table
 36  * can be written into a single eraseblock. In that case, garbage collection
 37  * consists of just writing the whole table, which therefore makes all other
 38  * eraseblocks reusable. In the case of the big model, dirty eraseblocks are
 39  * selected for garbage collection, which consists of marking the clean nodes in
 40  * that LEB as dirty, and then only the dirty nodes are written out. Also, in
 41  * the case of the big model, a table of LEB numbers is saved so that the entire
 42  * LPT does not to be scanned looking for empty eraseblocks when UBIFS is first
 43  * mounted.
 44  */
 45 
 46 #include "ubifs.h"
 47 #include <linux/crc16.h>
 48 #include <linux/math64.h>
 49 #include <linux/slab.h>
 50 
 51 /**
 52  * do_calc_lpt_geom - calculate sizes for the LPT area.
 53  * @c: the UBIFS file-system description object
 54  *
 55  * Calculate the sizes of LPT bit fields, nodes, and tree, based on the
 56  * properties of the flash and whether LPT is "big" (c->big_lpt).
 57  */
 58 static void do_calc_lpt_geom(struct ubifs_info *c)
 59 {
 60         int i, n, bits, per_leb_wastage, max_pnode_cnt;
 61         long long sz, tot_wastage;
 62 
 63         n = c->main_lebs + c->max_leb_cnt - c->leb_cnt;
 64         max_pnode_cnt = DIV_ROUND_UP(n, UBIFS_LPT_FANOUT);
 65 
 66         c->lpt_hght = 1;
 67         n = UBIFS_LPT_FANOUT;
 68         while (n < max_pnode_cnt) {
 69                 c->lpt_hght += 1;
 70                 n <<= UBIFS_LPT_FANOUT_SHIFT;
 71         }
 72 
 73         c->pnode_cnt = DIV_ROUND_UP(c->main_lebs, UBIFS_LPT_FANOUT);
 74 
 75         n = DIV_ROUND_UP(c->pnode_cnt, UBIFS_LPT_FANOUT);
 76         c->nnode_cnt = n;
 77         for (i = 1; i < c->lpt_hght; i++) {
 78                 n = DIV_ROUND_UP(n, UBIFS_LPT_FANOUT);
 79                 c->nnode_cnt += n;
 80         }
 81 
 82         c->space_bits = fls(c->leb_size) - 3;
 83         c->lpt_lnum_bits = fls(c->lpt_lebs);
 84         c->lpt_offs_bits = fls(c->leb_size - 1);
 85         c->lpt_spc_bits = fls(c->leb_size);
 86 
 87         n = DIV_ROUND_UP(c->max_leb_cnt, UBIFS_LPT_FANOUT);
 88         c->pcnt_bits = fls(n - 1);
 89 
 90         c->lnum_bits = fls(c->max_leb_cnt - 1);
 91 
 92         bits = UBIFS_LPT_CRC_BITS + UBIFS_LPT_TYPE_BITS +
 93                (c->big_lpt ? c->pcnt_bits : 0) +
 94                (c->space_bits * 2 + 1) * UBIFS_LPT_FANOUT;
 95         c->pnode_sz = (bits + 7) / 8;
 96 
 97         bits = UBIFS_LPT_CRC_BITS + UBIFS_LPT_TYPE_BITS +
 98                (c->big_lpt ? c->pcnt_bits : 0) +
 99                (c->lpt_lnum_bits + c->lpt_offs_bits) * UBIFS_LPT_FANOUT;
100         c->nnode_sz = (bits + 7) / 8;
101 
102         bits = UBIFS_LPT_CRC_BITS + UBIFS_LPT_TYPE_BITS +
103                c->lpt_lebs * c->lpt_spc_bits * 2;
104         c->ltab_sz = (bits + 7) / 8;
105 
106         bits = UBIFS_LPT_CRC_BITS + UBIFS_LPT_TYPE_BITS +
107                c->lnum_bits * c->lsave_cnt;
108         c->lsave_sz = (bits + 7) / 8;
109 
110         /* Calculate the minimum LPT size */
111         c->lpt_sz = (long long)c->pnode_cnt * c->pnode_sz;
112         c->lpt_sz += (long long)c->nnode_cnt * c->nnode_sz;
113         c->lpt_sz += c->ltab_sz;
114         if (c->big_lpt)
115                 c->lpt_sz += c->lsave_sz;
116 
117         /* Add wastage */
118         sz = c->lpt_sz;
119         per_leb_wastage = max_t(int, c->pnode_sz, c->nnode_sz);
120         sz += per_leb_wastage;
121         tot_wastage = per_leb_wastage;
122         while (sz > c->leb_size) {
123                 sz += per_leb_wastage;
124                 sz -= c->leb_size;
125                 tot_wastage += per_leb_wastage;
126         }
127         tot_wastage += ALIGN(sz, c->min_io_size) - sz;
128         c->lpt_sz += tot_wastage;
129 }
130 
131 /**
132  * ubifs_calc_lpt_geom - calculate and check sizes for the LPT area.
133  * @c: the UBIFS file-system description object
134  *
135  * This function returns %0 on success and a negative error code on failure.
136  */
137 int ubifs_calc_lpt_geom(struct ubifs_info *c)
138 {
139         int lebs_needed;
140         long long sz;
141 
142         do_calc_lpt_geom(c);
143 
144         /* Verify that lpt_lebs is big enough */
145         sz = c->lpt_sz * 2; /* Must have at least 2 times the size */
146         lebs_needed = div_u64(sz + c->leb_size - 1, c->leb_size);
147         if (lebs_needed > c->lpt_lebs) {
148                 ubifs_err(c, "too few LPT LEBs");
149                 return -EINVAL;
150         }
151 
152         /* Verify that ltab fits in a single LEB (since ltab is a single node */
153         if (c->ltab_sz > c->leb_size) {
154                 ubifs_err(c, "LPT ltab too big");
155                 return -EINVAL;
156         }
157 
158         c->check_lpt_free = c->big_lpt;
159         return 0;
160 }
161 
162 /**
163  * calc_dflt_lpt_geom - calculate default LPT geometry.
164  * @c: the UBIFS file-system description object
165  * @main_lebs: number of main area LEBs is passed and returned here
166  * @big_lpt: whether the LPT area is "big" is returned here
167  *
168  * The size of the LPT area depends on parameters that themselves are dependent
169  * on the size of the LPT area. This function, successively recalculates the LPT
170  * area geometry until the parameters and resultant geometry are consistent.
171  *
172  * This function returns %0 on success and a negative error code on failure.
173  */
174 static int calc_dflt_lpt_geom(struct ubifs_info *c, int *main_lebs,
175                               int *big_lpt)
176 {
177         int i, lebs_needed;
178         long long sz;
179 
180         /* Start by assuming the minimum number of LPT LEBs */
181         c->lpt_lebs = UBIFS_MIN_LPT_LEBS;
182         c->main_lebs = *main_lebs - c->lpt_lebs;
183         if (c->main_lebs <= 0)
184                 return -EINVAL;
185 
186         /* And assume we will use the small LPT model */
187         c->big_lpt = 0;
188 
189         /*
190          * Calculate the geometry based on assumptions above and then see if it
191          * makes sense
192          */
193         do_calc_lpt_geom(c);
194 
195         /* Small LPT model must have lpt_sz < leb_size */
196         if (c->lpt_sz > c->leb_size) {
197                 /* Nope, so try again using big LPT model */
198                 c->big_lpt = 1;
199                 do_calc_lpt_geom(c);
200         }
201 
202         /* Now check there are enough LPT LEBs */
203         for (i = 0; i < 64 ; i++) {
204                 sz = c->lpt_sz * 4; /* Allow 4 times the size */
205                 lebs_needed = div_u64(sz + c->leb_size - 1, c->leb_size);
206                 if (lebs_needed > c->lpt_lebs) {
207                         /* Not enough LPT LEBs so try again with more */
208                         c->lpt_lebs = lebs_needed;
209                         c->main_lebs = *main_lebs - c->lpt_lebs;
210                         if (c->main_lebs <= 0)
211                                 return -EINVAL;
212                         do_calc_lpt_geom(c);
213                         continue;
214                 }
215                 if (c->ltab_sz > c->leb_size) {
216                         ubifs_err(c, "LPT ltab too big");
217                         return -EINVAL;
218                 }
219                 *main_lebs = c->main_lebs;
220                 *big_lpt = c->big_lpt;
221                 return 0;
222         }
223         return -EINVAL;
224 }
225 
226 /**
227  * pack_bits - pack bit fields end-to-end.
228  * @addr: address at which to pack (passed and next address returned)
229  * @pos: bit position at which to pack (passed and next position returned)
230  * @val: value to pack
231  * @nrbits: number of bits of value to pack (1-32)
232  */
233 static void pack_bits(uint8_t **addr, int *pos, uint32_t val, int nrbits)
234 {
235         uint8_t *p = *addr;
236         int b = *pos;
237 
238         ubifs_assert(nrbits > 0);
239         ubifs_assert(nrbits <= 32);
240         ubifs_assert(*pos >= 0);
241         ubifs_assert(*pos < 8);
242         ubifs_assert((val >> nrbits) == 0 || nrbits == 32);
243         if (b) {
244                 *p |= ((uint8_t)val) << b;
245                 nrbits += b;
246                 if (nrbits > 8) {
247                         *++p = (uint8_t)(val >>= (8 - b));
248                         if (nrbits > 16) {
249                                 *++p = (uint8_t)(val >>= 8);
250                                 if (nrbits > 24) {
251                                         *++p = (uint8_t)(val >>= 8);
252                                         if (nrbits > 32)
253                                                 *++p = (uint8_t)(val >>= 8);
254                                 }
255                         }
256                 }
257         } else {
258                 *p = (uint8_t)val;
259                 if (nrbits > 8) {
260                         *++p = (uint8_t)(val >>= 8);
261                         if (nrbits > 16) {
262                                 *++p = (uint8_t)(val >>= 8);
263                                 if (nrbits > 24)
264                                         *++p = (uint8_t)(val >>= 8);
265                         }
266                 }
267         }
268         b = nrbits & 7;
269         if (b == 0)
270                 p++;
271         *addr = p;
272         *pos = b;
273 }
274 
275 /**
276  * ubifs_unpack_bits - unpack bit fields.
277  * @addr: address at which to unpack (passed and next address returned)
278  * @pos: bit position at which to unpack (passed and next position returned)
279  * @nrbits: number of bits of value to unpack (1-32)
280  *
281  * This functions returns the value unpacked.
282  */
283 uint32_t ubifs_unpack_bits(uint8_t **addr, int *pos, int nrbits)
284 {
285         const int k = 32 - nrbits;
286         uint8_t *p = *addr;
287         int b = *pos;
288         uint32_t uninitialized_var(val);
289         const int bytes = (nrbits + b + 7) >> 3;
290 
291         ubifs_assert(nrbits > 0);
292         ubifs_assert(nrbits <= 32);
293         ubifs_assert(*pos >= 0);
294         ubifs_assert(*pos < 8);
295         if (b) {
296                 switch (bytes) {
297                 case 2:
298                         val = p[1];
299                         break;
300                 case 3:
301                         val = p[1] | ((uint32_t)p[2] << 8);
302                         break;
303                 case 4:
304                         val = p[1] | ((uint32_t)p[2] << 8) |
305                                      ((uint32_t)p[3] << 16);
306                         break;
307                 case 5:
308                         val = p[1] | ((uint32_t)p[2] << 8) |
309                                      ((uint32_t)p[3] << 16) |
310                                      ((uint32_t)p[4] << 24);
311                 }
312                 val <<= (8 - b);
313                 val |= *p >> b;
314                 nrbits += b;
315         } else {
316                 switch (bytes) {
317                 case 1:
318                         val = p[0];
319                         break;
320                 case 2:
321                         val = p[0] | ((uint32_t)p[1] << 8);
322                         break;
323                 case 3:
324                         val = p[0] | ((uint32_t)p[1] << 8) |
325                                      ((uint32_t)p[2] << 16);
326                         break;
327                 case 4:
328                         val = p[0] | ((uint32_t)p[1] << 8) |
329                                      ((uint32_t)p[2] << 16) |
330                                      ((uint32_t)p[3] << 24);
331                         break;
332                 }
333         }
334         val <<= k;
335         val >>= k;
336         b = nrbits & 7;
337         p += nrbits >> 3;
338         *addr = p;
339         *pos = b;
340         ubifs_assert((val >> nrbits) == 0 || nrbits - b == 32);
341         return val;
342 }
343 
344 /**
345  * ubifs_pack_pnode - pack all the bit fields of a pnode.
346  * @c: UBIFS file-system description object
347  * @buf: buffer into which to pack
348  * @pnode: pnode to pack
349  */
350 void ubifs_pack_pnode(struct ubifs_info *c, void *buf,
351                       struct ubifs_pnode *pnode)
352 {
353         uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
354         int i, pos = 0;
355         uint16_t crc;
356 
357         pack_bits(&addr, &pos, UBIFS_LPT_PNODE, UBIFS_LPT_TYPE_BITS);
358         if (c->big_lpt)
359                 pack_bits(&addr, &pos, pnode->num, c->pcnt_bits);
360         for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
361                 pack_bits(&addr, &pos, pnode->lprops[i].free >> 3,
362                           c->space_bits);
363                 pack_bits(&addr, &pos, pnode->lprops[i].dirty >> 3,
364                           c->space_bits);
365                 if (pnode->lprops[i].flags & LPROPS_INDEX)
366                         pack_bits(&addr, &pos, 1, 1);
367                 else
368                         pack_bits(&addr, &pos, 0, 1);
369         }
370         crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
371                     c->pnode_sz - UBIFS_LPT_CRC_BYTES);
372         addr = buf;
373         pos = 0;
374         pack_bits(&addr, &pos, crc, UBIFS_LPT_CRC_BITS);
375 }
376 
377 /**
378  * ubifs_pack_nnode - pack all the bit fields of a nnode.
379  * @c: UBIFS file-system description object
380  * @buf: buffer into which to pack
381  * @nnode: nnode to pack
382  */
383 void ubifs_pack_nnode(struct ubifs_info *c, void *buf,
384                       struct ubifs_nnode *nnode)
385 {
386         uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
387         int i, pos = 0;
388         uint16_t crc;
389 
390         pack_bits(&addr, &pos, UBIFS_LPT_NNODE, UBIFS_LPT_TYPE_BITS);
391         if (c->big_lpt)
392                 pack_bits(&addr, &pos, nnode->num, c->pcnt_bits);
393         for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
394                 int lnum = nnode->nbranch[i].lnum;
395 
396                 if (lnum == 0)
397                         lnum = c->lpt_last + 1;
398                 pack_bits(&addr, &pos, lnum - c->lpt_first, c->lpt_lnum_bits);
399                 pack_bits(&addr, &pos, nnode->nbranch[i].offs,
400                           c->lpt_offs_bits);
401         }
402         crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
403                     c->nnode_sz - UBIFS_LPT_CRC_BYTES);
404         addr = buf;
405         pos = 0;
406         pack_bits(&addr, &pos, crc, UBIFS_LPT_CRC_BITS);
407 }
408 
409 /**
410  * ubifs_pack_ltab - pack the LPT's own lprops table.
411  * @c: UBIFS file-system description object
412  * @buf: buffer into which to pack
413  * @ltab: LPT's own lprops table to pack
414  */
415 void ubifs_pack_ltab(struct ubifs_info *c, void *buf,
416                      struct ubifs_lpt_lprops *ltab)
417 {
418         uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
419         int i, pos = 0;
420         uint16_t crc;
421 
422         pack_bits(&addr, &pos, UBIFS_LPT_LTAB, UBIFS_LPT_TYPE_BITS);
423         for (i = 0; i < c->lpt_lebs; i++) {
424                 pack_bits(&addr, &pos, ltab[i].free, c->lpt_spc_bits);
425                 pack_bits(&addr, &pos, ltab[i].dirty, c->lpt_spc_bits);
426         }
427         crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
428                     c->ltab_sz - UBIFS_LPT_CRC_BYTES);
429         addr = buf;
430         pos = 0;
431         pack_bits(&addr, &pos, crc, UBIFS_LPT_CRC_BITS);
432 }
433 
434 /**
435  * ubifs_pack_lsave - pack the LPT's save table.
436  * @c: UBIFS file-system description object
437  * @buf: buffer into which to pack
438  * @lsave: LPT's save table to pack
439  */
440 void ubifs_pack_lsave(struct ubifs_info *c, void *buf, int *lsave)
441 {
442         uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
443         int i, pos = 0;
444         uint16_t crc;
445 
446         pack_bits(&addr, &pos, UBIFS_LPT_LSAVE, UBIFS_LPT_TYPE_BITS);
447         for (i = 0; i < c->lsave_cnt; i++)
448                 pack_bits(&addr, &pos, lsave[i], c->lnum_bits);
449         crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
450                     c->lsave_sz - UBIFS_LPT_CRC_BYTES);
451         addr = buf;
452         pos = 0;
453         pack_bits(&addr, &pos, crc, UBIFS_LPT_CRC_BITS);
454 }
455 
456 /**
457  * ubifs_add_lpt_dirt - add dirty space to LPT LEB properties.
458  * @c: UBIFS file-system description object
459  * @lnum: LEB number to which to add dirty space
460  * @dirty: amount of dirty space to add
461  */
462 void ubifs_add_lpt_dirt(struct ubifs_info *c, int lnum, int dirty)
463 {
464         if (!dirty || !lnum)
465                 return;
466         dbg_lp("LEB %d add %d to %d",
467                lnum, dirty, c->ltab[lnum - c->lpt_first].dirty);
468         ubifs_assert(lnum >= c->lpt_first && lnum <= c->lpt_last);
469         c->ltab[lnum - c->lpt_first].dirty += dirty;
470 }
471 
472 /**
473  * set_ltab - set LPT LEB properties.
474  * @c: UBIFS file-system description object
475  * @lnum: LEB number
476  * @free: amount of free space
477  * @dirty: amount of dirty space
478  */
479 static void set_ltab(struct ubifs_info *c, int lnum, int free, int dirty)
480 {
481         dbg_lp("LEB %d free %d dirty %d to %d %d",
482                lnum, c->ltab[lnum - c->lpt_first].free,
483                c->ltab[lnum - c->lpt_first].dirty, free, dirty);
484         ubifs_assert(lnum >= c->lpt_first && lnum <= c->lpt_last);
485         c->ltab[lnum - c->lpt_first].free = free;
486         c->ltab[lnum - c->lpt_first].dirty = dirty;
487 }
488 
489 /**
490  * ubifs_add_nnode_dirt - add dirty space to LPT LEB properties.
491  * @c: UBIFS file-system description object
492  * @nnode: nnode for which to add dirt
493  */
494 void ubifs_add_nnode_dirt(struct ubifs_info *c, struct ubifs_nnode *nnode)
495 {
496         struct ubifs_nnode *np = nnode->parent;
497 
498         if (np)
499                 ubifs_add_lpt_dirt(c, np->nbranch[nnode->iip].lnum,
500                                    c->nnode_sz);
501         else {
502                 ubifs_add_lpt_dirt(c, c->lpt_lnum, c->nnode_sz);
503                 if (!(c->lpt_drty_flgs & LTAB_DIRTY)) {
504                         c->lpt_drty_flgs |= LTAB_DIRTY;
505                         ubifs_add_lpt_dirt(c, c->ltab_lnum, c->ltab_sz);
506                 }
507         }
508 }
509 
510 /**
511  * add_pnode_dirt - add dirty space to LPT LEB properties.
512  * @c: UBIFS file-system description object
513  * @pnode: pnode for which to add dirt
514  */
515 static void add_pnode_dirt(struct ubifs_info *c, struct ubifs_pnode *pnode)
516 {
517         ubifs_add_lpt_dirt(c, pnode->parent->nbranch[pnode->iip].lnum,
518                            c->pnode_sz);
519 }
520 
521 /**
522  * calc_nnode_num - calculate nnode number.
523  * @row: the row in the tree (root is zero)
524  * @col: the column in the row (leftmost is zero)
525  *
526  * The nnode number is a number that uniquely identifies a nnode and can be used
527  * easily to traverse the tree from the root to that nnode.
528  *
529  * This function calculates and returns the nnode number for the nnode at @row
530  * and @col.
531  */
532 static int calc_nnode_num(int row, int col)
533 {
534         int num, bits;
535 
536         num = 1;
537         while (row--) {
538                 bits = (col & (UBIFS_LPT_FANOUT - 1));
539                 col >>= UBIFS_LPT_FANOUT_SHIFT;
540                 num <<= UBIFS_LPT_FANOUT_SHIFT;
541                 num |= bits;
542         }
543         return num;
544 }
545 
546 /**
547  * calc_nnode_num_from_parent - calculate nnode number.
548  * @c: UBIFS file-system description object
549  * @parent: parent nnode
550  * @iip: index in parent
551  *
552  * The nnode number is a number that uniquely identifies a nnode and can be used
553  * easily to traverse the tree from the root to that nnode.
554  *
555  * This function calculates and returns the nnode number based on the parent's
556  * nnode number and the index in parent.
557  */
558 static int calc_nnode_num_from_parent(const struct ubifs_info *c,
559                                       struct ubifs_nnode *parent, int iip)
560 {
561         int num, shft;
562 
563         if (!parent)
564                 return 1;
565         shft = (c->lpt_hght - parent->level) * UBIFS_LPT_FANOUT_SHIFT;
566         num = parent->num ^ (1 << shft);
567         num |= (UBIFS_LPT_FANOUT + iip) << shft;
568         return num;
569 }
570 
571 /**
572  * calc_pnode_num_from_parent - calculate pnode number.
573  * @c: UBIFS file-system description object
574  * @parent: parent nnode
575  * @iip: index in parent
576  *
577  * The pnode number is a number that uniquely identifies a pnode and can be used
578  * easily to traverse the tree from the root to that pnode.
579  *
580  * This function calculates and returns the pnode number based on the parent's
581  * nnode number and the index in parent.
582  */
583 static int calc_pnode_num_from_parent(const struct ubifs_info *c,
584                                       struct ubifs_nnode *parent, int iip)
585 {
586         int i, n = c->lpt_hght - 1, pnum = parent->num, num = 0;
587 
588         for (i = 0; i < n; i++) {
589                 num <<= UBIFS_LPT_FANOUT_SHIFT;
590                 num |= pnum & (UBIFS_LPT_FANOUT - 1);
591                 pnum >>= UBIFS_LPT_FANOUT_SHIFT;
592         }
593         num <<= UBIFS_LPT_FANOUT_SHIFT;
594         num |= iip;
595         return num;
596 }
597 
598 /**
599  * ubifs_create_dflt_lpt - create default LPT.
600  * @c: UBIFS file-system description object
601  * @main_lebs: number of main area LEBs is passed and returned here
602  * @lpt_first: LEB number of first LPT LEB
603  * @lpt_lebs: number of LEBs for LPT is passed and returned here
604  * @big_lpt: use big LPT model is passed and returned here
605  *
606  * This function returns %0 on success and a negative error code on failure.
607  */
608 int ubifs_create_dflt_lpt(struct ubifs_info *c, int *main_lebs, int lpt_first,
609                           int *lpt_lebs, int *big_lpt)
610 {
611         int lnum, err = 0, node_sz, iopos, i, j, cnt, len, alen, row;
612         int blnum, boffs, bsz, bcnt;
613         struct ubifs_pnode *pnode = NULL;
614         struct ubifs_nnode *nnode = NULL;
615         void *buf = NULL, *p;
616         struct ubifs_lpt_lprops *ltab = NULL;
617         int *lsave = NULL;
618 
619         err = calc_dflt_lpt_geom(c, main_lebs, big_lpt);
620         if (err)
621                 return err;
622         *lpt_lebs = c->lpt_lebs;
623 
624         /* Needed by 'ubifs_pack_nnode()' and 'set_ltab()' */
625         c->lpt_first = lpt_first;
626         /* Needed by 'set_ltab()' */
627         c->lpt_last = lpt_first + c->lpt_lebs - 1;
628         /* Needed by 'ubifs_pack_lsave()' */
629         c->main_first = c->leb_cnt - *main_lebs;
630 
631         lsave = kmalloc(sizeof(int) * c->lsave_cnt, GFP_KERNEL);
632         pnode = kzalloc(sizeof(struct ubifs_pnode), GFP_KERNEL);
633         nnode = kzalloc(sizeof(struct ubifs_nnode), GFP_KERNEL);
634         buf = vmalloc(c->leb_size);
635         ltab = vmalloc(sizeof(struct ubifs_lpt_lprops) * c->lpt_lebs);
636         if (!pnode || !nnode || !buf || !ltab || !lsave) {
637                 err = -ENOMEM;
638                 goto out;
639         }
640 
641         ubifs_assert(!c->ltab);
642         c->ltab = ltab; /* Needed by set_ltab */
643 
644         /* Initialize LPT's own lprops */
645         for (i = 0; i < c->lpt_lebs; i++) {
646                 ltab[i].free = c->leb_size;
647                 ltab[i].dirty = 0;
648                 ltab[i].tgc = 0;
649                 ltab[i].cmt = 0;
650         }
651 
652         lnum = lpt_first;
653         p = buf;
654         /* Number of leaf nodes (pnodes) */
655         cnt = c->pnode_cnt;
656 
657         /*
658          * The first pnode contains the LEB properties for the LEBs that contain
659          * the root inode node and the root index node of the index tree.
660          */
661         node_sz = ALIGN(ubifs_idx_node_sz(c, 1), 8);
662         iopos = ALIGN(node_sz, c->min_io_size);
663         pnode->lprops[0].free = c->leb_size - iopos;
664         pnode->lprops[0].dirty = iopos - node_sz;
665         pnode->lprops[0].flags = LPROPS_INDEX;
666 
667         node_sz = UBIFS_INO_NODE_SZ;
668         iopos = ALIGN(node_sz, c->min_io_size);
669         pnode->lprops[1].free = c->leb_size - iopos;
670         pnode->lprops[1].dirty = iopos - node_sz;
671 
672         for (i = 2; i < UBIFS_LPT_FANOUT; i++)
673                 pnode->lprops[i].free = c->leb_size;
674 
675         /* Add first pnode */
676         ubifs_pack_pnode(c, p, pnode);
677         p += c->pnode_sz;
678         len = c->pnode_sz;
679         pnode->num += 1;
680 
681         /* Reset pnode values for remaining pnodes */
682         pnode->lprops[0].free = c->leb_size;
683         pnode->lprops[0].dirty = 0;
684         pnode->lprops[0].flags = 0;
685 
686         pnode->lprops[1].free = c->leb_size;
687         pnode->lprops[1].dirty = 0;
688 
689         /*
690          * To calculate the internal node branches, we keep information about
691          * the level below.
692          */
693         blnum = lnum; /* LEB number of level below */
694         boffs = 0; /* Offset of level below */
695         bcnt = cnt; /* Number of nodes in level below */
696         bsz = c->pnode_sz; /* Size of nodes in level below */
697 
698         /* Add all remaining pnodes */
699         for (i = 1; i < cnt; i++) {
700                 if (len + c->pnode_sz > c->leb_size) {
701                         alen = ALIGN(len, c->min_io_size);
702                         set_ltab(c, lnum, c->leb_size - alen, alen - len);
703                         memset(p, 0xff, alen - len);
704                         err = ubifs_leb_change(c, lnum++, buf, alen);
705                         if (err)
706                                 goto out;
707                         p = buf;
708                         len = 0;
709                 }
710                 ubifs_pack_pnode(c, p, pnode);
711                 p += c->pnode_sz;
712                 len += c->pnode_sz;
713                 /*
714                  * pnodes are simply numbered left to right starting at zero,
715                  * which means the pnode number can be used easily to traverse
716                  * down the tree to the corresponding pnode.
717                  */
718                 pnode->num += 1;
719         }
720 
721         row = 0;
722         for (i = UBIFS_LPT_FANOUT; cnt > i; i <<= UBIFS_LPT_FANOUT_SHIFT)
723                 row += 1;
724         /* Add all nnodes, one level at a time */
725         while (1) {
726                 /* Number of internal nodes (nnodes) at next level */
727                 cnt = DIV_ROUND_UP(cnt, UBIFS_LPT_FANOUT);
728                 for (i = 0; i < cnt; i++) {
729                         if (len + c->nnode_sz > c->leb_size) {
730                                 alen = ALIGN(len, c->min_io_size);
731                                 set_ltab(c, lnum, c->leb_size - alen,
732                                             alen - len);
733                                 memset(p, 0xff, alen - len);
734                                 err = ubifs_leb_change(c, lnum++, buf, alen);
735                                 if (err)
736                                         goto out;
737                                 p = buf;
738                                 len = 0;
739                         }
740                         /* Only 1 nnode at this level, so it is the root */
741                         if (cnt == 1) {
742                                 c->lpt_lnum = lnum;
743                                 c->lpt_offs = len;
744                         }
745                         /* Set branches to the level below */
746                         for (j = 0; j < UBIFS_LPT_FANOUT; j++) {
747                                 if (bcnt) {
748                                         if (boffs + bsz > c->leb_size) {
749                                                 blnum += 1;
750                                                 boffs = 0;
751                                         }
752                                         nnode->nbranch[j].lnum = blnum;
753                                         nnode->nbranch[j].offs = boffs;
754                                         boffs += bsz;
755                                         bcnt--;
756                                 } else {
757                                         nnode->nbranch[j].lnum = 0;
758                                         nnode->nbranch[j].offs = 0;
759                                 }
760                         }
761                         nnode->num = calc_nnode_num(row, i);
762                         ubifs_pack_nnode(c, p, nnode);
763                         p += c->nnode_sz;
764                         len += c->nnode_sz;
765                 }
766                 /* Only 1 nnode at this level, so it is the root */
767                 if (cnt == 1)
768                         break;
769                 /* Update the information about the level below */
770                 bcnt = cnt;
771                 bsz = c->nnode_sz;
772                 row -= 1;
773         }
774 
775         if (*big_lpt) {
776                 /* Need to add LPT's save table */
777                 if (len + c->lsave_sz > c->leb_size) {
778                         alen = ALIGN(len, c->min_io_size);
779                         set_ltab(c, lnum, c->leb_size - alen, alen - len);
780                         memset(p, 0xff, alen - len);
781                         err = ubifs_leb_change(c, lnum++, buf, alen);
782                         if (err)
783                                 goto out;
784                         p = buf;
785                         len = 0;
786                 }
787 
788                 c->lsave_lnum = lnum;
789                 c->lsave_offs = len;
790 
791                 for (i = 0; i < c->lsave_cnt && i < *main_lebs; i++)
792                         lsave[i] = c->main_first + i;
793                 for (; i < c->lsave_cnt; i++)
794                         lsave[i] = c->main_first;
795 
796                 ubifs_pack_lsave(c, p, lsave);
797                 p += c->lsave_sz;
798                 len += c->lsave_sz;
799         }
800 
801         /* Need to add LPT's own LEB properties table */
802         if (len + c->ltab_sz > c->leb_size) {
803                 alen = ALIGN(len, c->min_io_size);
804                 set_ltab(c, lnum, c->leb_size - alen, alen - len);
805                 memset(p, 0xff, alen - len);
806                 err = ubifs_leb_change(c, lnum++, buf, alen);
807                 if (err)
808                         goto out;
809                 p = buf;
810                 len = 0;
811         }
812 
813         c->ltab_lnum = lnum;
814         c->ltab_offs = len;
815 
816         /* Update ltab before packing it */
817         len += c->ltab_sz;
818         alen = ALIGN(len, c->min_io_size);
819         set_ltab(c, lnum, c->leb_size - alen, alen - len);
820 
821         ubifs_pack_ltab(c, p, ltab);
822         p += c->ltab_sz;
823 
824         /* Write remaining buffer */
825         memset(p, 0xff, alen - len);
826         err = ubifs_leb_change(c, lnum, buf, alen);
827         if (err)
828                 goto out;
829 
830         c->nhead_lnum = lnum;
831         c->nhead_offs = ALIGN(len, c->min_io_size);
832 
833         dbg_lp("space_bits %d", c->space_bits);
834         dbg_lp("lpt_lnum_bits %d", c->lpt_lnum_bits);
835         dbg_lp("lpt_offs_bits %d", c->lpt_offs_bits);
836         dbg_lp("lpt_spc_bits %d", c->lpt_spc_bits);
837         dbg_lp("pcnt_bits %d", c->pcnt_bits);
838         dbg_lp("lnum_bits %d", c->lnum_bits);
839         dbg_lp("pnode_sz %d", c->pnode_sz);
840         dbg_lp("nnode_sz %d", c->nnode_sz);
841         dbg_lp("ltab_sz %d", c->ltab_sz);
842         dbg_lp("lsave_sz %d", c->lsave_sz);
843         dbg_lp("lsave_cnt %d", c->lsave_cnt);
844         dbg_lp("lpt_hght %d", c->lpt_hght);
845         dbg_lp("big_lpt %d", c->big_lpt);
846         dbg_lp("LPT root is at %d:%d", c->lpt_lnum, c->lpt_offs);
847         dbg_lp("LPT head is at %d:%d", c->nhead_lnum, c->nhead_offs);
848         dbg_lp("LPT ltab is at %d:%d", c->ltab_lnum, c->ltab_offs);
849         if (c->big_lpt)
850                 dbg_lp("LPT lsave is at %d:%d", c->lsave_lnum, c->lsave_offs);
851 out:
852         c->ltab = NULL;
853         kfree(lsave);
854         vfree(ltab);
855         vfree(buf);
856         kfree(nnode);
857         kfree(pnode);
858         return err;
859 }
860 
861 /**
862  * update_cats - add LEB properties of a pnode to LEB category lists and heaps.
863  * @c: UBIFS file-system description object
864  * @pnode: pnode
865  *
866  * When a pnode is loaded into memory, the LEB properties it contains are added,
867  * by this function, to the LEB category lists and heaps.
868  */
869 static void update_cats(struct ubifs_info *c, struct ubifs_pnode *pnode)
870 {
871         int i;
872 
873         for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
874                 int cat = pnode->lprops[i].flags & LPROPS_CAT_MASK;
875                 int lnum = pnode->lprops[i].lnum;
876 
877                 if (!lnum)
878                         return;
879                 ubifs_add_to_cat(c, &pnode->lprops[i], cat);
880         }
881 }
882 
883 /**
884  * replace_cats - add LEB properties of a pnode to LEB category lists and heaps.
885  * @c: UBIFS file-system description object
886  * @old_pnode: pnode copied
887  * @new_pnode: pnode copy
888  *
889  * During commit it is sometimes necessary to copy a pnode
890  * (see dirty_cow_pnode).  When that happens, references in
891  * category lists and heaps must be replaced.  This function does that.
892  */
893 static void replace_cats(struct ubifs_info *c, struct ubifs_pnode *old_pnode,
894                          struct ubifs_pnode *new_pnode)
895 {
896         int i;
897 
898         for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
899                 if (!new_pnode->lprops[i].lnum)
900                         return;
901                 ubifs_replace_cat(c, &old_pnode->lprops[i],
902                                   &new_pnode->lprops[i]);
903         }
904 }
905 
906 /**
907  * check_lpt_crc - check LPT node crc is correct.
908  * @c: UBIFS file-system description object
909  * @buf: buffer containing node
910  * @len: length of node
911  *
912  * This function returns %0 on success and a negative error code on failure.
913  */
914 static int check_lpt_crc(const struct ubifs_info *c, void *buf, int len)
915 {
916         int pos = 0;
917         uint8_t *addr = buf;
918         uint16_t crc, calc_crc;
919 
920         crc = ubifs_unpack_bits(&addr, &pos, UBIFS_LPT_CRC_BITS);
921         calc_crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
922                          len - UBIFS_LPT_CRC_BYTES);
923         if (crc != calc_crc) {
924                 ubifs_err(c, "invalid crc in LPT node: crc %hx calc %hx",
925                           crc, calc_crc);
926                 dump_stack();
927                 return -EINVAL;
928         }
929         return 0;
930 }
931 
932 /**
933  * check_lpt_type - check LPT node type is correct.
934  * @c: UBIFS file-system description object
935  * @addr: address of type bit field is passed and returned updated here
936  * @pos: position of type bit field is passed and returned updated here
937  * @type: expected type
938  *
939  * This function returns %0 on success and a negative error code on failure.
940  */
941 static int check_lpt_type(const struct ubifs_info *c, uint8_t **addr,
942                           int *pos, int type)
943 {
944         int node_type;
945 
946         node_type = ubifs_unpack_bits(addr, pos, UBIFS_LPT_TYPE_BITS);
947         if (node_type != type) {
948                 ubifs_err(c, "invalid type (%d) in LPT node type %d",
949                           node_type, type);
950                 dump_stack();
951                 return -EINVAL;
952         }
953         return 0;
954 }
955 
956 /**
957  * unpack_pnode - unpack a pnode.
958  * @c: UBIFS file-system description object
959  * @buf: buffer containing packed pnode to unpack
960  * @pnode: pnode structure to fill
961  *
962  * This function returns %0 on success and a negative error code on failure.
963  */
964 static int unpack_pnode(const struct ubifs_info *c, void *buf,
965                         struct ubifs_pnode *pnode)
966 {
967         uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
968         int i, pos = 0, err;
969 
970         err = check_lpt_type(c, &addr, &pos, UBIFS_LPT_PNODE);
971         if (err)
972                 return err;
973         if (c->big_lpt)
974                 pnode->num = ubifs_unpack_bits(&addr, &pos, c->pcnt_bits);
975         for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
976                 struct ubifs_lprops * const lprops = &pnode->lprops[i];
977 
978                 lprops->free = ubifs_unpack_bits(&addr, &pos, c->space_bits);
979                 lprops->free <<= 3;
980                 lprops->dirty = ubifs_unpack_bits(&addr, &pos, c->space_bits);
981                 lprops->dirty <<= 3;
982 
983                 if (ubifs_unpack_bits(&addr, &pos, 1))
984                         lprops->flags = LPROPS_INDEX;
985                 else
986                         lprops->flags = 0;
987                 lprops->flags |= ubifs_categorize_lprops(c, lprops);
988         }
989         err = check_lpt_crc(c, buf, c->pnode_sz);
990         return err;
991 }
992 
993 /**
994  * ubifs_unpack_nnode - unpack a nnode.
995  * @c: UBIFS file-system description object
996  * @buf: buffer containing packed nnode to unpack
997  * @nnode: nnode structure to fill
998  *
999  * This function returns %0 on success and a negative error code on failure.
1000  */
1001 int ubifs_unpack_nnode(const struct ubifs_info *c, void *buf,
1002                        struct ubifs_nnode *nnode)
1003 {
1004         uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
1005         int i, pos = 0, err;
1006 
1007         err = check_lpt_type(c, &addr, &pos, UBIFS_LPT_NNODE);
1008         if (err)
1009                 return err;
1010         if (c->big_lpt)
1011                 nnode->num = ubifs_unpack_bits(&addr, &pos, c->pcnt_bits);
1012         for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1013                 int lnum;
1014 
1015                 lnum = ubifs_unpack_bits(&addr, &pos, c->lpt_lnum_bits) +
1016                        c->lpt_first;
1017                 if (lnum == c->lpt_last + 1)
1018                         lnum = 0;
1019                 nnode->nbranch[i].lnum = lnum;
1020                 nnode->nbranch[i].offs = ubifs_unpack_bits(&addr, &pos,
1021                                                      c->lpt_offs_bits);
1022         }
1023         err = check_lpt_crc(c, buf, c->nnode_sz);
1024         return err;
1025 }
1026 
1027 /**
1028  * unpack_ltab - unpack the LPT's own lprops table.
1029  * @c: UBIFS file-system description object
1030  * @buf: buffer from which to unpack
1031  *
1032  * This function returns %0 on success and a negative error code on failure.
1033  */
1034 static int unpack_ltab(const struct ubifs_info *c, void *buf)
1035 {
1036         uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
1037         int i, pos = 0, err;
1038 
1039         err = check_lpt_type(c, &addr, &pos, UBIFS_LPT_LTAB);
1040         if (err)
1041                 return err;
1042         for (i = 0; i < c->lpt_lebs; i++) {
1043                 int free = ubifs_unpack_bits(&addr, &pos, c->lpt_spc_bits);
1044                 int dirty = ubifs_unpack_bits(&addr, &pos, c->lpt_spc_bits);
1045 
1046                 if (free < 0 || free > c->leb_size || dirty < 0 ||
1047                     dirty > c->leb_size || free + dirty > c->leb_size)
1048                         return -EINVAL;
1049 
1050                 c->ltab[i].free = free;
1051                 c->ltab[i].dirty = dirty;
1052                 c->ltab[i].tgc = 0;
1053                 c->ltab[i].cmt = 0;
1054         }
1055         err = check_lpt_crc(c, buf, c->ltab_sz);
1056         return err;
1057 }
1058 
1059 /**
1060  * unpack_lsave - unpack the LPT's save table.
1061  * @c: UBIFS file-system description object
1062  * @buf: buffer from which to unpack
1063  *
1064  * This function returns %0 on success and a negative error code on failure.
1065  */
1066 static int unpack_lsave(const struct ubifs_info *c, void *buf)
1067 {
1068         uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
1069         int i, pos = 0, err;
1070 
1071         err = check_lpt_type(c, &addr, &pos, UBIFS_LPT_LSAVE);
1072         if (err)
1073                 return err;
1074         for (i = 0; i < c->lsave_cnt; i++) {
1075                 int lnum = ubifs_unpack_bits(&addr, &pos, c->lnum_bits);
1076 
1077                 if (lnum < c->main_first || lnum >= c->leb_cnt)
1078                         return -EINVAL;
1079                 c->lsave[i] = lnum;
1080         }
1081         err = check_lpt_crc(c, buf, c->lsave_sz);
1082         return err;
1083 }
1084 
1085 /**
1086  * validate_nnode - validate a nnode.
1087  * @c: UBIFS file-system description object
1088  * @nnode: nnode to validate
1089  * @parent: parent nnode (or NULL for the root nnode)
1090  * @iip: index in parent
1091  *
1092  * This function returns %0 on success and a negative error code on failure.
1093  */
1094 static int validate_nnode(const struct ubifs_info *c, struct ubifs_nnode *nnode,
1095                           struct ubifs_nnode *parent, int iip)
1096 {
1097         int i, lvl, max_offs;
1098 
1099         if (c->big_lpt) {
1100                 int num = calc_nnode_num_from_parent(c, parent, iip);
1101 
1102                 if (nnode->num != num)
1103                         return -EINVAL;
1104         }
1105         lvl = parent ? parent->level - 1 : c->lpt_hght;
1106         if (lvl < 1)
1107                 return -EINVAL;
1108         if (lvl == 1)
1109                 max_offs = c->leb_size - c->pnode_sz;
1110         else
1111                 max_offs = c->leb_size - c->nnode_sz;
1112         for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1113                 int lnum = nnode->nbranch[i].lnum;
1114                 int offs = nnode->nbranch[i].offs;
1115 
1116                 if (lnum == 0) {
1117                         if (offs != 0)
1118                                 return -EINVAL;
1119                         continue;
1120                 }
1121                 if (lnum < c->lpt_first || lnum > c->lpt_last)
1122                         return -EINVAL;
1123                 if (offs < 0 || offs > max_offs)
1124                         return -EINVAL;
1125         }
1126         return 0;
1127 }
1128 
1129 /**
1130  * validate_pnode - validate a pnode.
1131  * @c: UBIFS file-system description object
1132  * @pnode: pnode to validate
1133  * @parent: parent nnode
1134  * @iip: index in parent
1135  *
1136  * This function returns %0 on success and a negative error code on failure.
1137  */
1138 static int validate_pnode(const struct ubifs_info *c, struct ubifs_pnode *pnode,
1139                           struct ubifs_nnode *parent, int iip)
1140 {
1141         int i;
1142 
1143         if (c->big_lpt) {
1144                 int num = calc_pnode_num_from_parent(c, parent, iip);
1145 
1146                 if (pnode->num != num)
1147                         return -EINVAL;
1148         }
1149         for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1150                 int free = pnode->lprops[i].free;
1151                 int dirty = pnode->lprops[i].dirty;
1152 
1153                 if (free < 0 || free > c->leb_size || free % c->min_io_size ||
1154                     (free & 7))
1155                         return -EINVAL;
1156                 if (dirty < 0 || dirty > c->leb_size || (dirty & 7))
1157                         return -EINVAL;
1158                 if (dirty + free > c->leb_size)
1159                         return -EINVAL;
1160         }
1161         return 0;
1162 }
1163 
1164 /**
1165  * set_pnode_lnum - set LEB numbers on a pnode.
1166  * @c: UBIFS file-system description object
1167  * @pnode: pnode to update
1168  *
1169  * This function calculates the LEB numbers for the LEB properties it contains
1170  * based on the pnode number.
1171  */
1172 static void set_pnode_lnum(const struct ubifs_info *c,
1173                            struct ubifs_pnode *pnode)
1174 {
1175         int i, lnum;
1176 
1177         lnum = (pnode->num << UBIFS_LPT_FANOUT_SHIFT) + c->main_first;
1178         for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1179                 if (lnum >= c->leb_cnt)
1180                         return;
1181                 pnode->lprops[i].lnum = lnum++;
1182         }
1183 }
1184 
1185 /**
1186  * ubifs_read_nnode - read a nnode from flash and link it to the tree in memory.
1187  * @c: UBIFS file-system description object
1188  * @parent: parent nnode (or NULL for the root)
1189  * @iip: index in parent
1190  *
1191  * This function returns %0 on success and a negative error code on failure.
1192  */
1193 int ubifs_read_nnode(struct ubifs_info *c, struct ubifs_nnode *parent, int iip)
1194 {
1195         struct ubifs_nbranch *branch = NULL;
1196         struct ubifs_nnode *nnode = NULL;
1197         void *buf = c->lpt_nod_buf;
1198         int err, lnum, offs;
1199 
1200         if (parent) {
1201                 branch = &parent->nbranch[iip];
1202                 lnum = branch->lnum;
1203                 offs = branch->offs;
1204         } else {
1205                 lnum = c->lpt_lnum;
1206                 offs = c->lpt_offs;
1207         }
1208         nnode = kzalloc(sizeof(struct ubifs_nnode), GFP_NOFS);
1209         if (!nnode) {
1210                 err = -ENOMEM;
1211                 goto out;
1212         }
1213         if (lnum == 0) {
1214                 /*
1215                  * This nnode was not written which just means that the LEB
1216                  * properties in the subtree below it describe empty LEBs. We
1217                  * make the nnode as though we had read it, which in fact means
1218                  * doing almost nothing.
1219                  */
1220                 if (c->big_lpt)
1221                         nnode->num = calc_nnode_num_from_parent(c, parent, iip);
1222         } else {
1223                 err = ubifs_leb_read(c, lnum, buf, offs, c->nnode_sz, 1);
1224                 if (err)
1225                         goto out;
1226                 err = ubifs_unpack_nnode(c, buf, nnode);
1227                 if (err)
1228                         goto out;
1229         }
1230         err = validate_nnode(c, nnode, parent, iip);
1231         if (err)
1232                 goto out;
1233         if (!c->big_lpt)
1234                 nnode->num = calc_nnode_num_from_parent(c, parent, iip);
1235         if (parent) {
1236                 branch->nnode = nnode;
1237                 nnode->level = parent->level - 1;
1238         } else {
1239                 c->nroot = nnode;
1240                 nnode->level = c->lpt_hght;
1241         }
1242         nnode->parent = parent;
1243         nnode->iip = iip;
1244         return 0;
1245 
1246 out:
1247         ubifs_err(c, "error %d reading nnode at %d:%d", err, lnum, offs);
1248         dump_stack();
1249         kfree(nnode);
1250         return err;
1251 }
1252 
1253 /**
1254  * read_pnode - read a pnode from flash and link it to the tree in memory.
1255  * @c: UBIFS file-system description object
1256  * @parent: parent nnode
1257  * @iip: index in parent
1258  *
1259  * This function returns %0 on success and a negative error code on failure.
1260  */
1261 static int read_pnode(struct ubifs_info *c, struct ubifs_nnode *parent, int iip)
1262 {
1263         struct ubifs_nbranch *branch;
1264         struct ubifs_pnode *pnode = NULL;
1265         void *buf = c->lpt_nod_buf;
1266         int err, lnum, offs;
1267 
1268         branch = &parent->nbranch[iip];
1269         lnum = branch->lnum;
1270         offs = branch->offs;
1271         pnode = kzalloc(sizeof(struct ubifs_pnode), GFP_NOFS);
1272         if (!pnode)
1273                 return -ENOMEM;
1274 
1275         if (lnum == 0) {
1276                 /*
1277                  * This pnode was not written which just means that the LEB
1278                  * properties in it describe empty LEBs. We make the pnode as
1279                  * though we had read it.
1280                  */
1281                 int i;
1282 
1283                 if (c->big_lpt)
1284                         pnode->num = calc_pnode_num_from_parent(c, parent, iip);
1285                 for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1286                         struct ubifs_lprops * const lprops = &pnode->lprops[i];
1287 
1288                         lprops->free = c->leb_size;
1289                         lprops->flags = ubifs_categorize_lprops(c, lprops);
1290                 }
1291         } else {
1292                 err = ubifs_leb_read(c, lnum, buf, offs, c->pnode_sz, 1);
1293                 if (err)
1294                         goto out;
1295                 err = unpack_pnode(c, buf, pnode);
1296                 if (err)
1297                         goto out;
1298         }
1299         err = validate_pnode(c, pnode, parent, iip);
1300         if (err)
1301                 goto out;
1302         if (!c->big_lpt)
1303                 pnode->num = calc_pnode_num_from_parent(c, parent, iip);
1304         branch->pnode = pnode;
1305         pnode->parent = parent;
1306         pnode->iip = iip;
1307         set_pnode_lnum(c, pnode);
1308         c->pnodes_have += 1;
1309         return 0;
1310 
1311 out:
1312         ubifs_err(c, "error %d reading pnode at %d:%d", err, lnum, offs);
1313         ubifs_dump_pnode(c, pnode, parent, iip);
1314         dump_stack();
1315         ubifs_err(c, "calc num: %d", calc_pnode_num_from_parent(c, parent, iip));
1316         kfree(pnode);
1317         return err;
1318 }
1319 
1320 /**
1321  * read_ltab - read LPT's own lprops table.
1322  * @c: UBIFS file-system description object
1323  *
1324  * This function returns %0 on success and a negative error code on failure.
1325  */
1326 static int read_ltab(struct ubifs_info *c)
1327 {
1328         int err;
1329         void *buf;
1330 
1331         buf = vmalloc(c->ltab_sz);
1332         if (!buf)
1333                 return -ENOMEM;
1334         err = ubifs_leb_read(c, c->ltab_lnum, buf, c->ltab_offs, c->ltab_sz, 1);
1335         if (err)
1336                 goto out;
1337         err = unpack_ltab(c, buf);
1338 out:
1339         vfree(buf);
1340         return err;
1341 }
1342 
1343 /**
1344  * read_lsave - read LPT's save table.
1345  * @c: UBIFS file-system description object
1346  *
1347  * This function returns %0 on success and a negative error code on failure.
1348  */
1349 static int read_lsave(struct ubifs_info *c)
1350 {
1351         int err, i;
1352         void *buf;
1353 
1354         buf = vmalloc(c->lsave_sz);
1355         if (!buf)
1356                 return -ENOMEM;
1357         err = ubifs_leb_read(c, c->lsave_lnum, buf, c->lsave_offs,
1358                              c->lsave_sz, 1);
1359         if (err)
1360                 goto out;
1361         err = unpack_lsave(c, buf);
1362         if (err)
1363                 goto out;
1364         for (i = 0; i < c->lsave_cnt; i++) {
1365                 int lnum = c->lsave[i];
1366                 struct ubifs_lprops *lprops;
1367 
1368                 /*
1369                  * Due to automatic resizing, the values in the lsave table
1370                  * could be beyond the volume size - just ignore them.
1371                  */
1372                 if (lnum >= c->leb_cnt)
1373                         continue;
1374                 lprops = ubifs_lpt_lookup(c, lnum);
1375                 if (IS_ERR(lprops)) {
1376                         err = PTR_ERR(lprops);
1377                         goto out;
1378                 }
1379         }
1380 out:
1381         vfree(buf);
1382         return err;
1383 }
1384 
1385 /**
1386  * ubifs_get_nnode - get a nnode.
1387  * @c: UBIFS file-system description object
1388  * @parent: parent nnode (or NULL for the root)
1389  * @iip: index in parent
1390  *
1391  * This function returns a pointer to the nnode on success or a negative error
1392  * code on failure.
1393  */
1394 struct ubifs_nnode *ubifs_get_nnode(struct ubifs_info *c,
1395                                     struct ubifs_nnode *parent, int iip)
1396 {
1397         struct ubifs_nbranch *branch;
1398         struct ubifs_nnode *nnode;
1399         int err;
1400 
1401         branch = &parent->nbranch[iip];
1402         nnode = branch->nnode;
1403         if (nnode)
1404                 return nnode;
1405         err = ubifs_read_nnode(c, parent, iip);
1406         if (err)
1407                 return ERR_PTR(err);
1408         return branch->nnode;
1409 }
1410 
1411 /**
1412  * ubifs_get_pnode - get a pnode.
1413  * @c: UBIFS file-system description object
1414  * @parent: parent nnode
1415  * @iip: index in parent
1416  *
1417  * This function returns a pointer to the pnode on success or a negative error
1418  * code on failure.
1419  */
1420 struct ubifs_pnode *ubifs_get_pnode(struct ubifs_info *c,
1421                                     struct ubifs_nnode *parent, int iip)
1422 {
1423         struct ubifs_nbranch *branch;
1424         struct ubifs_pnode *pnode;
1425         int err;
1426 
1427         branch = &parent->nbranch[iip];
1428         pnode = branch->pnode;
1429         if (pnode)
1430                 return pnode;
1431         err = read_pnode(c, parent, iip);
1432         if (err)
1433                 return ERR_PTR(err);
1434         update_cats(c, branch->pnode);
1435         return branch->pnode;
1436 }
1437 
1438 /**
1439  * ubifs_lpt_lookup - lookup LEB properties in the LPT.
1440  * @c: UBIFS file-system description object
1441  * @lnum: LEB number to lookup
1442  *
1443  * This function returns a pointer to the LEB properties on success or a
1444  * negative error code on failure.
1445  */
1446 struct ubifs_lprops *ubifs_lpt_lookup(struct ubifs_info *c, int lnum)
1447 {
1448         int err, i, h, iip, shft;
1449         struct ubifs_nnode *nnode;
1450         struct ubifs_pnode *pnode;
1451 
1452         if (!c->nroot) {
1453                 err = ubifs_read_nnode(c, NULL, 0);
1454                 if (err)
1455                         return ERR_PTR(err);
1456         }
1457         nnode = c->nroot;
1458         i = lnum - c->main_first;
1459         shft = c->lpt_hght * UBIFS_LPT_FANOUT_SHIFT;
1460         for (h = 1; h < c->lpt_hght; h++) {
1461                 iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
1462                 shft -= UBIFS_LPT_FANOUT_SHIFT;
1463                 nnode = ubifs_get_nnode(c, nnode, iip);
1464                 if (IS_ERR(nnode))
1465                         return ERR_CAST(nnode);
1466         }
1467         iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
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 = kmemdup(nnode, sizeof(struct ubifs_nnode), GFP_NOFS);
1502         if (unlikely(!n))
1503                 return ERR_PTR(-ENOMEM);
1504 
1505         n->cnext = NULL;
1506         __set_bit(DIRTY_CNODE, &n->flags);
1507         __clear_bit(COW_CNODE, &n->flags);
1508 
1509         /* The children now have new parent */
1510         for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1511                 struct ubifs_nbranch *branch = &n->nbranch[i];
1512 
1513                 if (branch->cnode)
1514                         branch->cnode->parent = n;
1515         }
1516 
1517         ubifs_assert(!test_bit(OBSOLETE_CNODE, &nnode->flags));
1518         __set_bit(OBSOLETE_CNODE, &nnode->flags);
1519 
1520         c->dirty_nn_cnt += 1;
1521         ubifs_add_nnode_dirt(c, nnode);
1522         if (nnode->parent)
1523                 nnode->parent->nbranch[n->iip].nnode = n;
1524         else
1525                 c->nroot = n;
1526         return n;
1527 }
1528 
1529 /**
1530  * dirty_cow_pnode - ensure a pnode is not being committed.
1531  * @c: UBIFS file-system description object
1532  * @pnode: pnode to check
1533  *
1534  * Returns dirtied pnode on success or negative error code on failure.
1535  */
1536 static struct ubifs_pnode *dirty_cow_pnode(struct ubifs_info *c,
1537                                            struct ubifs_pnode *pnode)
1538 {
1539         struct ubifs_pnode *p;
1540 
1541         if (!test_bit(COW_CNODE, &pnode->flags)) {
1542                 /* pnode is not being committed */
1543                 if (!test_and_set_bit(DIRTY_CNODE, &pnode->flags)) {
1544                         c->dirty_pn_cnt += 1;
1545                         add_pnode_dirt(c, pnode);
1546                 }
1547                 return pnode;
1548         }
1549 
1550         /* pnode is being committed, so copy it */
1551         p = kmemdup(pnode, sizeof(struct ubifs_pnode), GFP_NOFS);
1552         if (unlikely(!p))
1553                 return ERR_PTR(-ENOMEM);
1554 
1555         p->cnext = NULL;
1556         __set_bit(DIRTY_CNODE, &p->flags);
1557         __clear_bit(COW_CNODE, &p->flags);
1558         replace_cats(c, pnode, p);
1559 
1560         ubifs_assert(!test_bit(OBSOLETE_CNODE, &pnode->flags));
1561         __set_bit(OBSOLETE_CNODE, &pnode->flags);
1562 
1563         c->dirty_pn_cnt += 1;
1564         add_pnode_dirt(c, pnode);
1565         pnode->parent->nbranch[p->iip].pnode = p;
1566         return p;
1567 }
1568 
1569 /**
1570  * ubifs_lpt_lookup_dirty - lookup LEB properties in the LPT.
1571  * @c: UBIFS file-system description object
1572  * @lnum: LEB number to lookup
1573  *
1574  * This function returns a pointer to the LEB properties on success or a
1575  * negative error code on failure.
1576  */
1577 struct ubifs_lprops *ubifs_lpt_lookup_dirty(struct ubifs_info *c, int lnum)
1578 {
1579         int err, i, h, iip, shft;
1580         struct ubifs_nnode *nnode;
1581         struct ubifs_pnode *pnode;
1582 
1583         if (!c->nroot) {
1584                 err = ubifs_read_nnode(c, NULL, 0);
1585                 if (err)
1586                         return ERR_PTR(err);
1587         }
1588         nnode = c->nroot;
1589         nnode = dirty_cow_nnode(c, nnode);
1590         if (IS_ERR(nnode))
1591                 return ERR_CAST(nnode);
1592         i = lnum - c->main_first;
1593         shft = c->lpt_hght * UBIFS_LPT_FANOUT_SHIFT;
1594         for (h = 1; h < c->lpt_hght; h++) {
1595                 iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
1596                 shft -= UBIFS_LPT_FANOUT_SHIFT;
1597                 nnode = ubifs_get_nnode(c, nnode, iip);
1598                 if (IS_ERR(nnode))
1599                         return ERR_CAST(nnode);
1600                 nnode = dirty_cow_nnode(c, nnode);
1601                 if (IS_ERR(nnode))
1602                         return ERR_CAST(nnode);
1603         }
1604         iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
1605         pnode = ubifs_get_pnode(c, nnode, iip);
1606         if (IS_ERR(pnode))
1607                 return ERR_CAST(pnode);
1608         pnode = dirty_cow_pnode(c, pnode);
1609         if (IS_ERR(pnode))
1610                 return ERR_CAST(pnode);
1611         iip = (i & (UBIFS_LPT_FANOUT - 1));
1612         dbg_lp("LEB %d, free %d, dirty %d, flags %d", lnum,
1613                pnode->lprops[iip].free, pnode->lprops[iip].dirty,
1614                pnode->lprops[iip].flags);
1615         ubifs_assert(test_bit(DIRTY_CNODE, &pnode->flags));
1616         return &pnode->lprops[iip];
1617 }
1618 
1619 /**
1620  * lpt_init_rd - initialize the LPT for reading.
1621  * @c: UBIFS file-system description object
1622  *
1623  * This function returns %0 on success and a negative error code on failure.
1624  */
1625 static int lpt_init_rd(struct ubifs_info *c)
1626 {
1627         int err, i;
1628 
1629         c->ltab = vmalloc(sizeof(struct ubifs_lpt_lprops) * c->lpt_lebs);
1630         if (!c->ltab)
1631                 return -ENOMEM;
1632 
1633         i = max_t(int, c->nnode_sz, c->pnode_sz);
1634         c->lpt_nod_buf = kmalloc(i, GFP_KERNEL);
1635         if (!c->lpt_nod_buf)
1636                 return -ENOMEM;
1637 
1638         for (i = 0; i < LPROPS_HEAP_CNT; i++) {
1639                 c->lpt_heap[i].arr = kmalloc(sizeof(void *) * LPT_HEAP_SZ,
1640                                              GFP_KERNEL);
1641                 if (!c->lpt_heap[i].arr)
1642                         return -ENOMEM;
1643                 c->lpt_heap[i].cnt = 0;
1644                 c->lpt_heap[i].max_cnt = LPT_HEAP_SZ;
1645         }
1646 
1647         c->dirty_idx.arr = kmalloc(sizeof(void *) * LPT_HEAP_SZ, GFP_KERNEL);
1648         if (!c->dirty_idx.arr)
1649                 return -ENOMEM;
1650         c->dirty_idx.cnt = 0;
1651         c->dirty_idx.max_cnt = LPT_HEAP_SZ;
1652 
1653         err = read_ltab(c);
1654         if (err)
1655                 return err;
1656 
1657         dbg_lp("space_bits %d", c->space_bits);
1658         dbg_lp("lpt_lnum_bits %d", c->lpt_lnum_bits);
1659         dbg_lp("lpt_offs_bits %d", c->lpt_offs_bits);
1660         dbg_lp("lpt_spc_bits %d", c->lpt_spc_bits);
1661         dbg_lp("pcnt_bits %d", c->pcnt_bits);
1662         dbg_lp("lnum_bits %d", c->lnum_bits);
1663         dbg_lp("pnode_sz %d", c->pnode_sz);
1664         dbg_lp("nnode_sz %d", c->nnode_sz);
1665         dbg_lp("ltab_sz %d", c->ltab_sz);
1666         dbg_lp("lsave_sz %d", c->lsave_sz);
1667         dbg_lp("lsave_cnt %d", c->lsave_cnt);
1668         dbg_lp("lpt_hght %d", c->lpt_hght);
1669         dbg_lp("big_lpt %d", c->big_lpt);
1670         dbg_lp("LPT root is at %d:%d", c->lpt_lnum, c->lpt_offs);
1671         dbg_lp("LPT head is at %d:%d", c->nhead_lnum, c->nhead_offs);
1672         dbg_lp("LPT ltab is at %d:%d", c->ltab_lnum, c->ltab_offs);
1673         if (c->big_lpt)
1674                 dbg_lp("LPT lsave is at %d:%d", c->lsave_lnum, c->lsave_offs);
1675 
1676         return 0;
1677 }
1678 
1679 /**
1680  * lpt_init_wr - initialize the LPT for writing.
1681  * @c: UBIFS file-system description object
1682  *
1683  * 'lpt_init_rd()' must have been called already.
1684  *
1685  * This function returns %0 on success and a negative error code on failure.
1686  */
1687 static int lpt_init_wr(struct ubifs_info *c)
1688 {
1689         int err, i;
1690 
1691         c->ltab_cmt = vmalloc(sizeof(struct ubifs_lpt_lprops) * c->lpt_lebs);
1692         if (!c->ltab_cmt)
1693                 return -ENOMEM;
1694 
1695         c->lpt_buf = vmalloc(c->leb_size);
1696         if (!c->lpt_buf)
1697                 return -ENOMEM;
1698 
1699         if (c->big_lpt) {
1700                 c->lsave = kmalloc(sizeof(int) * c->lsave_cnt, GFP_NOFS);
1701                 if (!c->lsave)
1702                         return -ENOMEM;
1703                 err = read_lsave(c);
1704                 if (err)
1705                         return err;
1706         }
1707 
1708         for (i = 0; i < c->lpt_lebs; i++)
1709                 if (c->ltab[i].free == c->leb_size) {
1710                         err = ubifs_leb_unmap(c, i + c->lpt_first);
1711                         if (err)
1712                                 return err;
1713                 }
1714 
1715         return 0;
1716 }
1717 
1718 /**
1719  * ubifs_lpt_init - initialize the LPT.
1720  * @c: UBIFS file-system description object
1721  * @rd: whether to initialize lpt for reading
1722  * @wr: whether to initialize lpt for writing
1723  *
1724  * For mounting 'rw', @rd and @wr are both true. For mounting 'ro', @rd is true
1725  * and @wr is false. For mounting from 'ro' to 'rw', @rd is false and @wr is
1726  * true.
1727  *
1728  * This function returns %0 on success and a negative error code on failure.
1729  */
1730 int ubifs_lpt_init(struct ubifs_info *c, int rd, int wr)
1731 {
1732         int err;
1733 
1734         if (rd) {
1735                 err = lpt_init_rd(c);
1736                 if (err)
1737                         goto out_err;
1738         }
1739 
1740         if (wr) {
1741                 err = lpt_init_wr(c);
1742                 if (err)
1743                         goto out_err;
1744         }
1745 
1746         return 0;
1747 
1748 out_err:
1749         if (wr)
1750                 ubifs_lpt_free(c, 1);
1751         if (rd)
1752                 ubifs_lpt_free(c, 0);
1753         return err;
1754 }
1755 
1756 /**
1757  * struct lpt_scan_node - somewhere to put nodes while we scan LPT.
1758  * @nnode: where to keep a nnode
1759  * @pnode: where to keep a pnode
1760  * @cnode: where to keep a cnode
1761  * @in_tree: is the node in the tree in memory
1762  * @ptr.nnode: pointer to the nnode (if it is an nnode) which may be here or in
1763  * the tree
1764  * @ptr.pnode: ditto for pnode
1765  * @ptr.cnode: ditto for cnode
1766  */
1767 struct lpt_scan_node {
1768         union {
1769                 struct ubifs_nnode nnode;
1770                 struct ubifs_pnode pnode;
1771                 struct ubifs_cnode cnode;
1772         };
1773         int in_tree;
1774         union {
1775                 struct ubifs_nnode *nnode;
1776                 struct ubifs_pnode *pnode;
1777                 struct ubifs_cnode *cnode;
1778         } ptr;
1779 };
1780 
1781 /**
1782  * scan_get_nnode - for the scan, get a nnode from either the tree or flash.
1783  * @c: the UBIFS file-system description object
1784  * @path: where to put the nnode
1785  * @parent: parent of the nnode
1786  * @iip: index in parent of the nnode
1787  *
1788  * This function returns a pointer to the nnode on success or a negative error
1789  * code on failure.
1790  */
1791 static struct ubifs_nnode *scan_get_nnode(struct ubifs_info *c,
1792                                           struct lpt_scan_node *path,
1793                                           struct ubifs_nnode *parent, int iip)
1794 {
1795         struct ubifs_nbranch *branch;
1796         struct ubifs_nnode *nnode;
1797         void *buf = c->lpt_nod_buf;
1798         int err;
1799 
1800         branch = &parent->nbranch[iip];
1801         nnode = branch->nnode;
1802         if (nnode) {
1803                 path->in_tree = 1;
1804                 path->ptr.nnode = nnode;
1805                 return nnode;
1806         }
1807         nnode = &path->nnode;
1808         path->in_tree = 0;
1809         path->ptr.nnode = nnode;
1810         memset(nnode, 0, sizeof(struct ubifs_nnode));
1811         if (branch->lnum == 0) {
1812                 /*
1813                  * This nnode was not written which just means that the LEB
1814                  * properties in the subtree below it describe empty LEBs. We
1815                  * make the nnode as though we had read it, which in fact means
1816                  * doing almost nothing.
1817                  */
1818                 if (c->big_lpt)
1819                         nnode->num = calc_nnode_num_from_parent(c, parent, iip);
1820         } else {
1821                 err = ubifs_leb_read(c, branch->lnum, buf, branch->offs,
1822                                      c->nnode_sz, 1);
1823                 if (err)
1824                         return ERR_PTR(err);
1825                 err = ubifs_unpack_nnode(c, buf, nnode);
1826                 if (err)
1827                         return ERR_PTR(err);
1828         }
1829         err = validate_nnode(c, nnode, parent, iip);
1830         if (err)
1831                 return ERR_PTR(err);
1832         if (!c->big_lpt)
1833                 nnode->num = calc_nnode_num_from_parent(c, parent, iip);
1834         nnode->level = parent->level - 1;
1835         nnode->parent = parent;
1836         nnode->iip = iip;
1837         return nnode;
1838 }
1839 
1840 /**
1841  * scan_get_pnode - for the scan, get a pnode from either the tree or flash.
1842  * @c: the UBIFS file-system description object
1843  * @path: where to put the pnode
1844  * @parent: parent of the pnode
1845  * @iip: index in parent of the pnode
1846  *
1847  * This function returns a pointer to the pnode on success or a negative error
1848  * code on failure.
1849  */
1850 static struct ubifs_pnode *scan_get_pnode(struct ubifs_info *c,
1851                                           struct lpt_scan_node *path,
1852                                           struct ubifs_nnode *parent, int iip)
1853 {
1854         struct ubifs_nbranch *branch;
1855         struct ubifs_pnode *pnode;
1856         void *buf = c->lpt_nod_buf;
1857         int err;
1858 
1859         branch = &parent->nbranch[iip];
1860         pnode = branch->pnode;
1861         if (pnode) {
1862                 path->in_tree = 1;
1863                 path->ptr.pnode = pnode;
1864                 return pnode;
1865         }
1866         pnode = &path->pnode;
1867         path->in_tree = 0;
1868         path->ptr.pnode = pnode;
1869         memset(pnode, 0, sizeof(struct ubifs_pnode));
1870         if (branch->lnum == 0) {
1871                 /*
1872                  * This pnode was not written which just means that the LEB
1873                  * properties in it describe empty LEBs. We make the pnode as
1874                  * though we had read it.
1875                  */
1876                 int i;
1877 
1878                 if (c->big_lpt)
1879                         pnode->num = calc_pnode_num_from_parent(c, parent, iip);
1880                 for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
1881                         struct ubifs_lprops * const lprops = &pnode->lprops[i];
1882 
1883                         lprops->free = c->leb_size;
1884                         lprops->flags = ubifs_categorize_lprops(c, lprops);
1885                 }
1886         } else {
1887                 ubifs_assert(branch->lnum >= c->lpt_first &&
1888                              branch->lnum <= c->lpt_last);
1889                 ubifs_assert(branch->offs >= 0 && branch->offs < c->leb_size);
1890                 err = ubifs_leb_read(c, branch->lnum, buf, branch->offs,
1891                                      c->pnode_sz, 1);
1892                 if (err)
1893                         return ERR_PTR(err);
1894                 err = unpack_pnode(c, buf, pnode);
1895                 if (err)
1896                         return ERR_PTR(err);
1897         }
1898         err = validate_pnode(c, pnode, parent, iip);
1899         if (err)
1900                 return ERR_PTR(err);
1901         if (!c->big_lpt)
1902                 pnode->num = calc_pnode_num_from_parent(c, parent, iip);
1903         pnode->parent = parent;
1904         pnode->iip = iip;
1905         set_pnode_lnum(c, pnode);
1906         return pnode;
1907 }
1908 
1909 /**
1910  * ubifs_lpt_scan_nolock - scan the LPT.
1911  * @c: the UBIFS file-system description object
1912  * @start_lnum: LEB number from which to start scanning
1913  * @end_lnum: LEB number at which to stop scanning
1914  * @scan_cb: callback function called for each lprops
1915  * @data: data to be passed to the callback function
1916  *
1917  * This function returns %0 on success and a negative error code on failure.
1918  */
1919 int ubifs_lpt_scan_nolock(struct ubifs_info *c, int start_lnum, int end_lnum,
1920                           ubifs_lpt_scan_callback scan_cb, void *data)
1921 {
1922         int err = 0, i, h, iip, shft;
1923         struct ubifs_nnode *nnode;
1924         struct ubifs_pnode *pnode;
1925         struct lpt_scan_node *path;
1926 
1927         if (start_lnum == -1) {
1928                 start_lnum = end_lnum + 1;
1929                 if (start_lnum >= c->leb_cnt)
1930                         start_lnum = c->main_first;
1931         }
1932 
1933         ubifs_assert(start_lnum >= c->main_first && start_lnum < c->leb_cnt);
1934         ubifs_assert(end_lnum >= c->main_first && end_lnum < c->leb_cnt);
1935 
1936         if (!c->nroot) {
1937                 err = ubifs_read_nnode(c, NULL, 0);
1938                 if (err)
1939                         return err;
1940         }
1941 
1942         path = kmalloc(sizeof(struct lpt_scan_node) * (c->lpt_hght + 1),
1943                        GFP_NOFS);
1944         if (!path)
1945                 return -ENOMEM;
1946 
1947         path[0].ptr.nnode = c->nroot;
1948         path[0].in_tree = 1;
1949 again:
1950         /* Descend to the pnode containing start_lnum */
1951         nnode = c->nroot;
1952         i = start_lnum - c->main_first;
1953         shft = c->lpt_hght * UBIFS_LPT_FANOUT_SHIFT;
1954         for (h = 1; h < c->lpt_hght; h++) {
1955                 iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
1956                 shft -= UBIFS_LPT_FANOUT_SHIFT;
1957                 nnode = scan_get_nnode(c, path + h, nnode, iip);
1958                 if (IS_ERR(nnode)) {
1959                         err = PTR_ERR(nnode);
1960                         goto out;
1961                 }
1962         }
1963         iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
1964         pnode = scan_get_pnode(c, path + h, nnode, iip);
1965         if (IS_ERR(pnode)) {
1966                 err = PTR_ERR(pnode);
1967                 goto out;
1968         }
1969         iip = (i & (UBIFS_LPT_FANOUT - 1));
1970 
1971         /* Loop for each lprops */
1972         while (1) {
1973                 struct ubifs_lprops *lprops = &pnode->lprops[iip];
1974                 int ret, lnum = lprops->lnum;
1975 
1976                 ret = scan_cb(c, lprops, path[h].in_tree, data);
1977                 if (ret < 0) {
1978                         err = ret;
1979                         goto out;
1980                 }
1981                 if (ret & LPT_SCAN_ADD) {
1982                         /* Add all the nodes in path to the tree in memory */
1983                         for (h = 1; h < c->lpt_hght; h++) {
1984                                 const size_t sz = sizeof(struct ubifs_nnode);
1985                                 struct ubifs_nnode *parent;
1986 
1987                                 if (path[h].in_tree)
1988                                         continue;
1989                                 nnode = kmemdup(&path[h].nnode, sz, GFP_NOFS);
1990                                 if (!nnode) {
1991                                         err = -ENOMEM;
1992                                         goto out;
1993                                 }
1994                                 parent = nnode->parent;
1995                                 parent->nbranch[nnode->iip].nnode = nnode;
1996                                 path[h].ptr.nnode = nnode;
1997                                 path[h].in_tree = 1;
1998                                 path[h + 1].cnode.parent = nnode;
1999                         }
2000                         if (path[h].in_tree)
2001                                 ubifs_ensure_cat(c, lprops);
2002                         else {
2003                                 const size_t sz = sizeof(struct ubifs_pnode);
2004                                 struct ubifs_nnode *parent;
2005 
2006                                 pnode = kmemdup(&path[h].pnode, sz, GFP_NOFS);
2007                                 if (!pnode) {
2008                                         err = -ENOMEM;
2009                                         goto out;
2010                                 }
2011                                 parent = pnode->parent;
2012                                 parent->nbranch[pnode->iip].pnode = pnode;
2013                                 path[h].ptr.pnode = pnode;
2014                                 path[h].in_tree = 1;
2015                                 update_cats(c, pnode);
2016                                 c->pnodes_have += 1;
2017                         }
2018                         err = dbg_check_lpt_nodes(c, (struct ubifs_cnode *)
2019                                                   c->nroot, 0, 0);
2020                         if (err)
2021                                 goto out;
2022                         err = dbg_check_cats(c);
2023                         if (err)
2024                                 goto out;
2025                 }
2026                 if (ret & LPT_SCAN_STOP) {
2027                         err = 0;
2028                         break;
2029                 }
2030                 /* Get the next lprops */
2031                 if (lnum == end_lnum) {
2032                         /*
2033                          * We got to the end without finding what we were
2034                          * looking for
2035                          */
2036                         err = -ENOSPC;
2037                         goto out;
2038                 }
2039                 if (lnum + 1 >= c->leb_cnt) {
2040                         /* Wrap-around to the beginning */
2041                         start_lnum = c->main_first;
2042                         goto again;
2043                 }
2044                 if (iip + 1 < UBIFS_LPT_FANOUT) {
2045                         /* Next lprops is in the same pnode */
2046                         iip += 1;
2047                         continue;
2048                 }
2049                 /* We need to get the next pnode. Go up until we can go right */
2050                 iip = pnode->iip;
2051                 while (1) {
2052                         h -= 1;
2053                         ubifs_assert(h >= 0);
2054                         nnode = path[h].ptr.nnode;
2055                         if (iip + 1 < UBIFS_LPT_FANOUT)
2056                                 break;
2057                         iip = nnode->iip;
2058                 }
2059                 /* Go right */
2060                 iip += 1;
2061                 /* Descend to the pnode */
2062                 h += 1;
2063                 for (; h < c->lpt_hght; h++) {
2064                         nnode = scan_get_nnode(c, path + h, nnode, iip);
2065                         if (IS_ERR(nnode)) {
2066                                 err = PTR_ERR(nnode);
2067                                 goto out;
2068                         }
2069                         iip = 0;
2070                 }
2071                 pnode = scan_get_pnode(c, path + h, nnode, iip);
2072                 if (IS_ERR(pnode)) {
2073                         err = PTR_ERR(pnode);
2074                         goto out;
2075                 }
2076                 iip = 0;
2077         }
2078 out:
2079         kfree(path);
2080         return err;
2081 }
2082 
2083 /**
2084  * dbg_chk_pnode - check a pnode.
2085  * @c: the UBIFS file-system description object
2086  * @pnode: pnode to check
2087  * @col: pnode column
2088  *
2089  * This function returns %0 on success and a negative error code on failure.
2090  */
2091 static int dbg_chk_pnode(struct ubifs_info *c, struct ubifs_pnode *pnode,
2092                          int col)
2093 {
2094         int i;
2095 
2096         if (pnode->num != col) {
2097                 ubifs_err(c, "pnode num %d expected %d parent num %d iip %d",
2098                           pnode->num, col, pnode->parent->num, pnode->iip);
2099                 return -EINVAL;
2100         }
2101         for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
2102                 struct ubifs_lprops *lp, *lprops = &pnode->lprops[i];
2103                 int lnum = (pnode->num << UBIFS_LPT_FANOUT_SHIFT) + i +
2104                            c->main_first;
2105                 int found, cat = lprops->flags & LPROPS_CAT_MASK;
2106                 struct ubifs_lpt_heap *heap;
2107                 struct list_head *list = NULL;
2108 
2109                 if (lnum >= c->leb_cnt)
2110                         continue;
2111                 if (lprops->lnum != lnum) {
2112                         ubifs_err(c, "bad LEB number %d expected %d",
2113                                   lprops->lnum, lnum);
2114                         return -EINVAL;
2115                 }
2116                 if (lprops->flags & LPROPS_TAKEN) {
2117                         if (cat != LPROPS_UNCAT) {
2118                                 ubifs_err(c, "LEB %d taken but not uncat %d",
2119                                           lprops->lnum, cat);
2120                                 return -EINVAL;
2121                         }
2122                         continue;
2123                 }
2124                 if (lprops->flags & LPROPS_INDEX) {
2125                         switch (cat) {
2126                         case LPROPS_UNCAT:
2127                         case LPROPS_DIRTY_IDX:
2128                         case LPROPS_FRDI_IDX:
2129                                 break;
2130                         default:
2131                                 ubifs_err(c, "LEB %d index but cat %d",
2132                                           lprops->lnum, cat);
2133                                 return -EINVAL;
2134                         }
2135                 } else {
2136                         switch (cat) {
2137                         case LPROPS_UNCAT:
2138                         case LPROPS_DIRTY:
2139                         case LPROPS_FREE:
2140                         case LPROPS_EMPTY:
2141                         case LPROPS_FREEABLE:
2142                                 break;
2143                         default:
2144                                 ubifs_err(c, "LEB %d not index but cat %d",
2145                                           lprops->lnum, cat);
2146                                 return -EINVAL;
2147                         }
2148                 }
2149                 switch (cat) {
2150                 case LPROPS_UNCAT:
2151                         list = &c->uncat_list;
2152                         break;
2153                 case LPROPS_EMPTY:
2154                         list = &c->empty_list;
2155                         break;
2156                 case LPROPS_FREEABLE:
2157                         list = &c->freeable_list;
2158                         break;
2159                 case LPROPS_FRDI_IDX:
2160                         list = &c->frdi_idx_list;
2161                         break;
2162                 }
2163                 found = 0;
2164                 switch (cat) {
2165                 case LPROPS_DIRTY:
2166                 case LPROPS_DIRTY_IDX:
2167                 case LPROPS_FREE:
2168                         heap = &c->lpt_heap[cat - 1];
2169                         if (lprops->hpos < heap->cnt &&
2170                             heap->arr[lprops->hpos] == lprops)
2171                                 found = 1;
2172                         break;
2173                 case LPROPS_UNCAT:
2174                 case LPROPS_EMPTY:
2175                 case LPROPS_FREEABLE:
2176                 case LPROPS_FRDI_IDX:
2177                         list_for_each_entry(lp, list, list)
2178                                 if (lprops == lp) {
2179                                         found = 1;
2180                                         break;
2181                                 }
2182                         break;
2183                 }
2184                 if (!found) {
2185                         ubifs_err(c, "LEB %d cat %d not found in cat heap/list",
2186                                   lprops->lnum, cat);
2187                         return -EINVAL;
2188                 }
2189                 switch (cat) {
2190                 case LPROPS_EMPTY:
2191                         if (lprops->free != c->leb_size) {
2192                                 ubifs_err(c, "LEB %d cat %d free %d dirty %d",
2193                                           lprops->lnum, cat, lprops->free,
2194                                           lprops->dirty);
2195                                 return -EINVAL;
2196                         }
2197                         break;
2198                 case LPROPS_FREEABLE:
2199                 case LPROPS_FRDI_IDX:
2200                         if (lprops->free + lprops->dirty != c->leb_size) {
2201                                 ubifs_err(c, "LEB %d cat %d free %d dirty %d",
2202                                           lprops->lnum, cat, lprops->free,
2203                                           lprops->dirty);
2204                                 return -EINVAL;
2205                         }
2206                         break;
2207                 }
2208         }
2209         return 0;
2210 }
2211 
2212 /**
2213  * dbg_check_lpt_nodes - check nnodes and pnodes.
2214  * @c: the UBIFS file-system description object
2215  * @cnode: next cnode (nnode or pnode) to check
2216  * @row: row of cnode (root is zero)
2217  * @col: column of cnode (leftmost is zero)
2218  *
2219  * This function returns %0 on success and a negative error code on failure.
2220  */
2221 int dbg_check_lpt_nodes(struct ubifs_info *c, struct ubifs_cnode *cnode,
2222                         int row, int col)
2223 {
2224         struct ubifs_nnode *nnode, *nn;
2225         struct ubifs_cnode *cn;
2226         int num, iip = 0, err;
2227 
2228         if (!dbg_is_chk_lprops(c))
2229                 return 0;
2230 
2231         while (cnode) {
2232                 ubifs_assert(row >= 0);
2233                 nnode = cnode->parent;
2234                 if (cnode->level) {
2235                         /* cnode is a nnode */
2236                         num = calc_nnode_num(row, col);
2237                         if (cnode->num != num) {
2238                                 ubifs_err(c, "nnode num %d expected %d parent num %d iip %d",
2239                                           cnode->num, num,
2240                                           (nnode ? nnode->num : 0), cnode->iip);
2241                                 return -EINVAL;
2242                         }
2243                         nn = (struct ubifs_nnode *)cnode;
2244                         while (iip < UBIFS_LPT_FANOUT) {
2245                                 cn = nn->nbranch[iip].cnode;
2246                                 if (cn) {
2247                                         /* Go down */
2248                                         row += 1;
2249                                         col <<= UBIFS_LPT_FANOUT_SHIFT;
2250                                         col += iip;
2251                                         iip = 0;
2252                                         cnode = cn;
2253                                         break;
2254                                 }
2255                                 /* Go right */
2256                                 iip += 1;
2257                         }
2258                         if (iip < UBIFS_LPT_FANOUT)
2259                                 continue;
2260                 } else {
2261                         struct ubifs_pnode *pnode;
2262 
2263                         /* cnode is a pnode */
2264                         pnode = (struct ubifs_pnode *)cnode;
2265                         err = dbg_chk_pnode(c, pnode, col);
2266                         if (err)
2267                                 return err;
2268                 }
2269                 /* Go up and to the right */
2270                 row -= 1;
2271                 col >>= UBIFS_LPT_FANOUT_SHIFT;
2272                 iip = cnode->iip + 1;
2273                 cnode = (struct ubifs_cnode *)nnode;
2274         }
2275         return 0;
2276 }
2277 

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