xref: /linux/drivers/mtd/ubi/fastmap.c (revision bb9707077b4ee5f77bc9939b057ff8a0d410296f)
1 /*
2  * Copyright (c) 2012 Linutronix GmbH
3  * Copyright (c) 2014 sigma star gmbh
4  * Author: Richard Weinberger <richard@nod.at>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; version 2.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
13  * the GNU General Public License for more details.
14  *
15  */
16 
17 #include <linux/crc32.h>
18 #include "ubi.h"
19 
20 /**
21  * init_seen - allocate memory for used for debugging.
22  * @ubi: UBI device description object
23  */
24 static inline int *init_seen(struct ubi_device *ubi)
25 {
26 	int *ret;
27 
28 	if (!ubi_dbg_chk_fastmap(ubi))
29 		return NULL;
30 
31 	ret = kcalloc(ubi->peb_count, sizeof(int), GFP_KERNEL);
32 	if (!ret)
33 		return ERR_PTR(-ENOMEM);
34 
35 	return ret;
36 }
37 
38 /**
39  * free_seen - free the seen logic integer array.
40  * @seen: integer array of @ubi->peb_count size
41  */
42 static inline void free_seen(int *seen)
43 {
44 	kfree(seen);
45 }
46 
47 /**
48  * set_seen - mark a PEB as seen.
49  * @ubi: UBI device description object
50  * @pnum: The PEB to be makred as seen
51  * @seen: integer array of @ubi->peb_count size
52  */
53 static inline void set_seen(struct ubi_device *ubi, int pnum, int *seen)
54 {
55 	if (!ubi_dbg_chk_fastmap(ubi) || !seen)
56 		return;
57 
58 	seen[pnum] = 1;
59 }
60 
61 /**
62  * self_check_seen - check whether all PEB have been seen by fastmap.
63  * @ubi: UBI device description object
64  * @seen: integer array of @ubi->peb_count size
65  */
66 static int self_check_seen(struct ubi_device *ubi, int *seen)
67 {
68 	int pnum, ret = 0;
69 
70 	if (!ubi_dbg_chk_fastmap(ubi) || !seen)
71 		return 0;
72 
73 	for (pnum = 0; pnum < ubi->peb_count; pnum++) {
74 		if (!seen[pnum] && ubi->lookuptbl[pnum]) {
75 			ubi_err(ubi, "self-check failed for PEB %d, fastmap didn't see it", pnum);
76 			ret = -EINVAL;
77 		}
78 	}
79 
80 	return ret;
81 }
82 
83 /**
84  * ubi_calc_fm_size - calculates the fastmap size in bytes for an UBI device.
85  * @ubi: UBI device description object
86  */
87 size_t ubi_calc_fm_size(struct ubi_device *ubi)
88 {
89 	size_t size;
90 
91 	size = sizeof(struct ubi_fm_sb) +
92 		sizeof(struct ubi_fm_hdr) +
93 		sizeof(struct ubi_fm_scan_pool) +
94 		sizeof(struct ubi_fm_scan_pool) +
95 		(ubi->peb_count * sizeof(struct ubi_fm_ec)) +
96 		(sizeof(struct ubi_fm_eba) +
97 		(ubi->peb_count * sizeof(__be32))) +
98 		sizeof(struct ubi_fm_volhdr) * UBI_MAX_VOLUMES;
99 	return roundup(size, ubi->leb_size);
100 }
101 
102 
103 /**
104  * new_fm_vhdr - allocate a new volume header for fastmap usage.
105  * @ubi: UBI device description object
106  * @vol_id: the VID of the new header
107  *
108  * Returns a new struct ubi_vid_hdr on success.
109  * NULL indicates out of memory.
110  */
111 static struct ubi_vid_hdr *new_fm_vhdr(struct ubi_device *ubi, int vol_id)
112 {
113 	struct ubi_vid_hdr *new;
114 
115 	new = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
116 	if (!new)
117 		goto out;
118 
119 	new->vol_type = UBI_VID_DYNAMIC;
120 	new->vol_id = cpu_to_be32(vol_id);
121 
122 	/* UBI implementations without fastmap support have to delete the
123 	 * fastmap.
124 	 */
125 	new->compat = UBI_COMPAT_DELETE;
126 
127 out:
128 	return new;
129 }
130 
131 /**
132  * add_aeb - create and add a attach erase block to a given list.
133  * @ai: UBI attach info object
134  * @list: the target list
135  * @pnum: PEB number of the new attach erase block
136  * @ec: erease counter of the new LEB
137  * @scrub: scrub this PEB after attaching
138  *
139  * Returns 0 on success, < 0 indicates an internal error.
140  */
141 static int add_aeb(struct ubi_attach_info *ai, struct list_head *list,
142 		   int pnum, int ec, int scrub)
143 {
144 	struct ubi_ainf_peb *aeb;
145 
146 	aeb = kmem_cache_alloc(ai->aeb_slab_cache, GFP_KERNEL);
147 	if (!aeb)
148 		return -ENOMEM;
149 
150 	aeb->pnum = pnum;
151 	aeb->ec = ec;
152 	aeb->lnum = -1;
153 	aeb->scrub = scrub;
154 	aeb->copy_flag = aeb->sqnum = 0;
155 
156 	ai->ec_sum += aeb->ec;
157 	ai->ec_count++;
158 
159 	if (ai->max_ec < aeb->ec)
160 		ai->max_ec = aeb->ec;
161 
162 	if (ai->min_ec > aeb->ec)
163 		ai->min_ec = aeb->ec;
164 
165 	list_add_tail(&aeb->u.list, list);
166 
167 	return 0;
168 }
169 
170 /**
171  * add_vol - create and add a new volume to ubi_attach_info.
172  * @ai: ubi_attach_info object
173  * @vol_id: VID of the new volume
174  * @used_ebs: number of used EBS
175  * @data_pad: data padding value of the new volume
176  * @vol_type: volume type
177  * @last_eb_bytes: number of bytes in the last LEB
178  *
179  * Returns the new struct ubi_ainf_volume on success.
180  * NULL indicates an error.
181  */
182 static struct ubi_ainf_volume *add_vol(struct ubi_attach_info *ai, int vol_id,
183 				       int used_ebs, int data_pad, u8 vol_type,
184 				       int last_eb_bytes)
185 {
186 	struct ubi_ainf_volume *av;
187 	struct rb_node **p = &ai->volumes.rb_node, *parent = NULL;
188 
189 	while (*p) {
190 		parent = *p;
191 		av = rb_entry(parent, struct ubi_ainf_volume, rb);
192 
193 		if (vol_id > av->vol_id)
194 			p = &(*p)->rb_left;
195 		else if (vol_id < av->vol_id)
196 			p = &(*p)->rb_right;
197 		else
198 			return ERR_PTR(-EINVAL);
199 	}
200 
201 	av = kmalloc(sizeof(struct ubi_ainf_volume), GFP_KERNEL);
202 	if (!av)
203 		goto out;
204 
205 	av->highest_lnum = av->leb_count = av->used_ebs = 0;
206 	av->vol_id = vol_id;
207 	av->data_pad = data_pad;
208 	av->last_data_size = last_eb_bytes;
209 	av->compat = 0;
210 	av->vol_type = vol_type;
211 	av->root = RB_ROOT;
212 	if (av->vol_type == UBI_STATIC_VOLUME)
213 		av->used_ebs = used_ebs;
214 
215 	dbg_bld("found volume (ID %i)", vol_id);
216 
217 	rb_link_node(&av->rb, parent, p);
218 	rb_insert_color(&av->rb, &ai->volumes);
219 
220 out:
221 	return av;
222 }
223 
224 /**
225  * assign_aeb_to_av - assigns a SEB to a given ainf_volume and removes it
226  * from it's original list.
227  * @ai: ubi_attach_info object
228  * @aeb: the to be assigned SEB
229  * @av: target scan volume
230  */
231 static void assign_aeb_to_av(struct ubi_attach_info *ai,
232 			     struct ubi_ainf_peb *aeb,
233 			     struct ubi_ainf_volume *av)
234 {
235 	struct ubi_ainf_peb *tmp_aeb;
236 	struct rb_node **p = &ai->volumes.rb_node, *parent = NULL;
237 
238 	p = &av->root.rb_node;
239 	while (*p) {
240 		parent = *p;
241 
242 		tmp_aeb = rb_entry(parent, struct ubi_ainf_peb, u.rb);
243 		if (aeb->lnum != tmp_aeb->lnum) {
244 			if (aeb->lnum < tmp_aeb->lnum)
245 				p = &(*p)->rb_left;
246 			else
247 				p = &(*p)->rb_right;
248 
249 			continue;
250 		} else
251 			break;
252 	}
253 
254 	list_del(&aeb->u.list);
255 	av->leb_count++;
256 
257 	rb_link_node(&aeb->u.rb, parent, p);
258 	rb_insert_color(&aeb->u.rb, &av->root);
259 }
260 
261 /**
262  * update_vol - inserts or updates a LEB which was found a pool.
263  * @ubi: the UBI device object
264  * @ai: attach info object
265  * @av: the volume this LEB belongs to
266  * @new_vh: the volume header derived from new_aeb
267  * @new_aeb: the AEB to be examined
268  *
269  * Returns 0 on success, < 0 indicates an internal error.
270  */
271 static int update_vol(struct ubi_device *ubi, struct ubi_attach_info *ai,
272 		      struct ubi_ainf_volume *av, struct ubi_vid_hdr *new_vh,
273 		      struct ubi_ainf_peb *new_aeb)
274 {
275 	struct rb_node **p = &av->root.rb_node, *parent = NULL;
276 	struct ubi_ainf_peb *aeb, *victim;
277 	int cmp_res;
278 
279 	while (*p) {
280 		parent = *p;
281 		aeb = rb_entry(parent, struct ubi_ainf_peb, u.rb);
282 
283 		if (be32_to_cpu(new_vh->lnum) != aeb->lnum) {
284 			if (be32_to_cpu(new_vh->lnum) < aeb->lnum)
285 				p = &(*p)->rb_left;
286 			else
287 				p = &(*p)->rb_right;
288 
289 			continue;
290 		}
291 
292 		/* This case can happen if the fastmap gets written
293 		 * because of a volume change (creation, deletion, ..).
294 		 * Then a PEB can be within the persistent EBA and the pool.
295 		 */
296 		if (aeb->pnum == new_aeb->pnum) {
297 			ubi_assert(aeb->lnum == new_aeb->lnum);
298 			kmem_cache_free(ai->aeb_slab_cache, new_aeb);
299 
300 			return 0;
301 		}
302 
303 		cmp_res = ubi_compare_lebs(ubi, aeb, new_aeb->pnum, new_vh);
304 		if (cmp_res < 0)
305 			return cmp_res;
306 
307 		/* new_aeb is newer */
308 		if (cmp_res & 1) {
309 			victim = kmem_cache_alloc(ai->aeb_slab_cache,
310 				GFP_KERNEL);
311 			if (!victim)
312 				return -ENOMEM;
313 
314 			victim->ec = aeb->ec;
315 			victim->pnum = aeb->pnum;
316 			list_add_tail(&victim->u.list, &ai->erase);
317 
318 			if (av->highest_lnum == be32_to_cpu(new_vh->lnum))
319 				av->last_data_size =
320 					be32_to_cpu(new_vh->data_size);
321 
322 			dbg_bld("vol %i: AEB %i's PEB %i is the newer",
323 				av->vol_id, aeb->lnum, new_aeb->pnum);
324 
325 			aeb->ec = new_aeb->ec;
326 			aeb->pnum = new_aeb->pnum;
327 			aeb->copy_flag = new_vh->copy_flag;
328 			aeb->scrub = new_aeb->scrub;
329 			kmem_cache_free(ai->aeb_slab_cache, new_aeb);
330 
331 		/* new_aeb is older */
332 		} else {
333 			dbg_bld("vol %i: AEB %i's PEB %i is old, dropping it",
334 				av->vol_id, aeb->lnum, new_aeb->pnum);
335 			list_add_tail(&new_aeb->u.list, &ai->erase);
336 		}
337 
338 		return 0;
339 	}
340 	/* This LEB is new, let's add it to the volume */
341 
342 	if (av->highest_lnum <= be32_to_cpu(new_vh->lnum)) {
343 		av->highest_lnum = be32_to_cpu(new_vh->lnum);
344 		av->last_data_size = be32_to_cpu(new_vh->data_size);
345 	}
346 
347 	if (av->vol_type == UBI_STATIC_VOLUME)
348 		av->used_ebs = be32_to_cpu(new_vh->used_ebs);
349 
350 	av->leb_count++;
351 
352 	rb_link_node(&new_aeb->u.rb, parent, p);
353 	rb_insert_color(&new_aeb->u.rb, &av->root);
354 
355 	return 0;
356 }
357 
358 /**
359  * process_pool_aeb - we found a non-empty PEB in a pool.
360  * @ubi: UBI device object
361  * @ai: attach info object
362  * @new_vh: the volume header derived from new_aeb
363  * @new_aeb: the AEB to be examined
364  *
365  * Returns 0 on success, < 0 indicates an internal error.
366  */
367 static int process_pool_aeb(struct ubi_device *ubi, struct ubi_attach_info *ai,
368 			    struct ubi_vid_hdr *new_vh,
369 			    struct ubi_ainf_peb *new_aeb)
370 {
371 	struct ubi_ainf_volume *av, *tmp_av = NULL;
372 	struct rb_node **p = &ai->volumes.rb_node, *parent = NULL;
373 	int found = 0;
374 
375 	if (be32_to_cpu(new_vh->vol_id) == UBI_FM_SB_VOLUME_ID ||
376 		be32_to_cpu(new_vh->vol_id) == UBI_FM_DATA_VOLUME_ID) {
377 		kmem_cache_free(ai->aeb_slab_cache, new_aeb);
378 
379 		return 0;
380 	}
381 
382 	/* Find the volume this SEB belongs to */
383 	while (*p) {
384 		parent = *p;
385 		tmp_av = rb_entry(parent, struct ubi_ainf_volume, rb);
386 
387 		if (be32_to_cpu(new_vh->vol_id) > tmp_av->vol_id)
388 			p = &(*p)->rb_left;
389 		else if (be32_to_cpu(new_vh->vol_id) < tmp_av->vol_id)
390 			p = &(*p)->rb_right;
391 		else {
392 			found = 1;
393 			break;
394 		}
395 	}
396 
397 	if (found)
398 		av = tmp_av;
399 	else {
400 		ubi_err(ubi, "orphaned volume in fastmap pool!");
401 		kmem_cache_free(ai->aeb_slab_cache, new_aeb);
402 		return UBI_BAD_FASTMAP;
403 	}
404 
405 	ubi_assert(be32_to_cpu(new_vh->vol_id) == av->vol_id);
406 
407 	return update_vol(ubi, ai, av, new_vh, new_aeb);
408 }
409 
410 /**
411  * unmap_peb - unmap a PEB.
412  * If fastmap detects a free PEB in the pool it has to check whether
413  * this PEB has been unmapped after writing the fastmap.
414  *
415  * @ai: UBI attach info object
416  * @pnum: The PEB to be unmapped
417  */
418 static void unmap_peb(struct ubi_attach_info *ai, int pnum)
419 {
420 	struct ubi_ainf_volume *av;
421 	struct rb_node *node, *node2;
422 	struct ubi_ainf_peb *aeb;
423 
424 	for (node = rb_first(&ai->volumes); node; node = rb_next(node)) {
425 		av = rb_entry(node, struct ubi_ainf_volume, rb);
426 
427 		for (node2 = rb_first(&av->root); node2;
428 		     node2 = rb_next(node2)) {
429 			aeb = rb_entry(node2, struct ubi_ainf_peb, u.rb);
430 			if (aeb->pnum == pnum) {
431 				rb_erase(&aeb->u.rb, &av->root);
432 				av->leb_count--;
433 				kmem_cache_free(ai->aeb_slab_cache, aeb);
434 				return;
435 			}
436 		}
437 	}
438 }
439 
440 /**
441  * scan_pool - scans a pool for changed (no longer empty PEBs).
442  * @ubi: UBI device object
443  * @ai: attach info object
444  * @pebs: an array of all PEB numbers in the to be scanned pool
445  * @pool_size: size of the pool (number of entries in @pebs)
446  * @max_sqnum: pointer to the maximal sequence number
447  * @free: list of PEBs which are most likely free (and go into @ai->free)
448  *
449  * Returns 0 on success, if the pool is unusable UBI_BAD_FASTMAP is returned.
450  * < 0 indicates an internal error.
451  */
452 static int scan_pool(struct ubi_device *ubi, struct ubi_attach_info *ai,
453 		     __be32 *pebs, int pool_size, unsigned long long *max_sqnum,
454 		     struct list_head *free)
455 {
456 	struct ubi_vid_hdr *vh;
457 	struct ubi_ec_hdr *ech;
458 	struct ubi_ainf_peb *new_aeb;
459 	int i, pnum, err, ret = 0;
460 
461 	ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
462 	if (!ech)
463 		return -ENOMEM;
464 
465 	vh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
466 	if (!vh) {
467 		kfree(ech);
468 		return -ENOMEM;
469 	}
470 
471 	dbg_bld("scanning fastmap pool: size = %i", pool_size);
472 
473 	/*
474 	 * Now scan all PEBs in the pool to find changes which have been made
475 	 * after the creation of the fastmap
476 	 */
477 	for (i = 0; i < pool_size; i++) {
478 		int scrub = 0;
479 		int image_seq;
480 
481 		pnum = be32_to_cpu(pebs[i]);
482 
483 		if (ubi_io_is_bad(ubi, pnum)) {
484 			ubi_err(ubi, "bad PEB in fastmap pool!");
485 			ret = UBI_BAD_FASTMAP;
486 			goto out;
487 		}
488 
489 		err = ubi_io_read_ec_hdr(ubi, pnum, ech, 0);
490 		if (err && err != UBI_IO_BITFLIPS) {
491 			ubi_err(ubi, "unable to read EC header! PEB:%i err:%i",
492 				pnum, err);
493 			ret = err > 0 ? UBI_BAD_FASTMAP : err;
494 			goto out;
495 		} else if (err == UBI_IO_BITFLIPS)
496 			scrub = 1;
497 
498 		/*
499 		 * Older UBI implementations have image_seq set to zero, so
500 		 * we shouldn't fail if image_seq == 0.
501 		 */
502 		image_seq = be32_to_cpu(ech->image_seq);
503 
504 		if (image_seq && (image_seq != ubi->image_seq)) {
505 			ubi_err(ubi, "bad image seq: 0x%x, expected: 0x%x",
506 				be32_to_cpu(ech->image_seq), ubi->image_seq);
507 			ret = UBI_BAD_FASTMAP;
508 			goto out;
509 		}
510 
511 		err = ubi_io_read_vid_hdr(ubi, pnum, vh, 0);
512 		if (err == UBI_IO_FF || err == UBI_IO_FF_BITFLIPS) {
513 			unsigned long long ec = be64_to_cpu(ech->ec);
514 			unmap_peb(ai, pnum);
515 			dbg_bld("Adding PEB to free: %i", pnum);
516 			if (err == UBI_IO_FF_BITFLIPS)
517 				add_aeb(ai, free, pnum, ec, 1);
518 			else
519 				add_aeb(ai, free, pnum, ec, 0);
520 			continue;
521 		} else if (err == 0 || err == UBI_IO_BITFLIPS) {
522 			dbg_bld("Found non empty PEB:%i in pool", pnum);
523 
524 			if (err == UBI_IO_BITFLIPS)
525 				scrub = 1;
526 
527 			new_aeb = kmem_cache_alloc(ai->aeb_slab_cache,
528 						   GFP_KERNEL);
529 			if (!new_aeb) {
530 				ret = -ENOMEM;
531 				goto out;
532 			}
533 
534 			new_aeb->ec = be64_to_cpu(ech->ec);
535 			new_aeb->pnum = pnum;
536 			new_aeb->lnum = be32_to_cpu(vh->lnum);
537 			new_aeb->sqnum = be64_to_cpu(vh->sqnum);
538 			new_aeb->copy_flag = vh->copy_flag;
539 			new_aeb->scrub = scrub;
540 
541 			if (*max_sqnum < new_aeb->sqnum)
542 				*max_sqnum = new_aeb->sqnum;
543 
544 			err = process_pool_aeb(ubi, ai, vh, new_aeb);
545 			if (err) {
546 				ret = err > 0 ? UBI_BAD_FASTMAP : err;
547 				goto out;
548 			}
549 		} else {
550 			/* We are paranoid and fall back to scanning mode */
551 			ubi_err(ubi, "fastmap pool PEBs contains damaged PEBs!");
552 			ret = err > 0 ? UBI_BAD_FASTMAP : err;
553 			goto out;
554 		}
555 
556 	}
557 
558 out:
559 	ubi_free_vid_hdr(ubi, vh);
560 	kfree(ech);
561 	return ret;
562 }
563 
564 /**
565  * count_fastmap_pebs - Counts the PEBs found by fastmap.
566  * @ai: The UBI attach info object
567  */
568 static int count_fastmap_pebs(struct ubi_attach_info *ai)
569 {
570 	struct ubi_ainf_peb *aeb;
571 	struct ubi_ainf_volume *av;
572 	struct rb_node *rb1, *rb2;
573 	int n = 0;
574 
575 	list_for_each_entry(aeb, &ai->erase, u.list)
576 		n++;
577 
578 	list_for_each_entry(aeb, &ai->free, u.list)
579 		n++;
580 
581 	 ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb)
582 		ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb)
583 			n++;
584 
585 	return n;
586 }
587 
588 /**
589  * ubi_attach_fastmap - creates ubi_attach_info from a fastmap.
590  * @ubi: UBI device object
591  * @ai: UBI attach info object
592  * @fm: the fastmap to be attached
593  *
594  * Returns 0 on success, UBI_BAD_FASTMAP if the found fastmap was unusable.
595  * < 0 indicates an internal error.
596  */
597 static int ubi_attach_fastmap(struct ubi_device *ubi,
598 			      struct ubi_attach_info *ai,
599 			      struct ubi_fastmap_layout *fm)
600 {
601 	struct list_head used, free;
602 	struct ubi_ainf_volume *av;
603 	struct ubi_ainf_peb *aeb, *tmp_aeb, *_tmp_aeb;
604 	struct ubi_fm_sb *fmsb;
605 	struct ubi_fm_hdr *fmhdr;
606 	struct ubi_fm_scan_pool *fmpl, *fmpl_wl;
607 	struct ubi_fm_ec *fmec;
608 	struct ubi_fm_volhdr *fmvhdr;
609 	struct ubi_fm_eba *fm_eba;
610 	int ret, i, j, pool_size, wl_pool_size;
611 	size_t fm_pos = 0, fm_size = ubi->fm_size;
612 	unsigned long long max_sqnum = 0;
613 	void *fm_raw = ubi->fm_buf;
614 
615 	INIT_LIST_HEAD(&used);
616 	INIT_LIST_HEAD(&free);
617 	ai->min_ec = UBI_MAX_ERASECOUNTER;
618 
619 	fmsb = (struct ubi_fm_sb *)(fm_raw);
620 	ai->max_sqnum = fmsb->sqnum;
621 	fm_pos += sizeof(struct ubi_fm_sb);
622 	if (fm_pos >= fm_size)
623 		goto fail_bad;
624 
625 	fmhdr = (struct ubi_fm_hdr *)(fm_raw + fm_pos);
626 	fm_pos += sizeof(*fmhdr);
627 	if (fm_pos >= fm_size)
628 		goto fail_bad;
629 
630 	if (be32_to_cpu(fmhdr->magic) != UBI_FM_HDR_MAGIC) {
631 		ubi_err(ubi, "bad fastmap header magic: 0x%x, expected: 0x%x",
632 			be32_to_cpu(fmhdr->magic), UBI_FM_HDR_MAGIC);
633 		goto fail_bad;
634 	}
635 
636 	fmpl = (struct ubi_fm_scan_pool *)(fm_raw + fm_pos);
637 	fm_pos += sizeof(*fmpl);
638 	if (fm_pos >= fm_size)
639 		goto fail_bad;
640 	if (be32_to_cpu(fmpl->magic) != UBI_FM_POOL_MAGIC) {
641 		ubi_err(ubi, "bad fastmap pool magic: 0x%x, expected: 0x%x",
642 			be32_to_cpu(fmpl->magic), UBI_FM_POOL_MAGIC);
643 		goto fail_bad;
644 	}
645 
646 	fmpl_wl = (struct ubi_fm_scan_pool *)(fm_raw + fm_pos);
647 	fm_pos += sizeof(*fmpl_wl);
648 	if (fm_pos >= fm_size)
649 		goto fail_bad;
650 	if (be32_to_cpu(fmpl_wl->magic) != UBI_FM_POOL_MAGIC) {
651 		ubi_err(ubi, "bad fastmap WL pool magic: 0x%x, expected: 0x%x",
652 			be32_to_cpu(fmpl_wl->magic), UBI_FM_POOL_MAGIC);
653 		goto fail_bad;
654 	}
655 
656 	pool_size = be16_to_cpu(fmpl->size);
657 	wl_pool_size = be16_to_cpu(fmpl_wl->size);
658 	fm->max_pool_size = be16_to_cpu(fmpl->max_size);
659 	fm->max_wl_pool_size = be16_to_cpu(fmpl_wl->max_size);
660 
661 	if (pool_size > UBI_FM_MAX_POOL_SIZE || pool_size < 0) {
662 		ubi_err(ubi, "bad pool size: %i", pool_size);
663 		goto fail_bad;
664 	}
665 
666 	if (wl_pool_size > UBI_FM_MAX_POOL_SIZE || wl_pool_size < 0) {
667 		ubi_err(ubi, "bad WL pool size: %i", wl_pool_size);
668 		goto fail_bad;
669 	}
670 
671 
672 	if (fm->max_pool_size > UBI_FM_MAX_POOL_SIZE ||
673 	    fm->max_pool_size < 0) {
674 		ubi_err(ubi, "bad maximal pool size: %i", fm->max_pool_size);
675 		goto fail_bad;
676 	}
677 
678 	if (fm->max_wl_pool_size > UBI_FM_MAX_POOL_SIZE ||
679 	    fm->max_wl_pool_size < 0) {
680 		ubi_err(ubi, "bad maximal WL pool size: %i",
681 			fm->max_wl_pool_size);
682 		goto fail_bad;
683 	}
684 
685 	/* read EC values from free list */
686 	for (i = 0; i < be32_to_cpu(fmhdr->free_peb_count); i++) {
687 		fmec = (struct ubi_fm_ec *)(fm_raw + fm_pos);
688 		fm_pos += sizeof(*fmec);
689 		if (fm_pos >= fm_size)
690 			goto fail_bad;
691 
692 		add_aeb(ai, &ai->free, be32_to_cpu(fmec->pnum),
693 			be32_to_cpu(fmec->ec), 0);
694 	}
695 
696 	/* read EC values from used list */
697 	for (i = 0; i < be32_to_cpu(fmhdr->used_peb_count); i++) {
698 		fmec = (struct ubi_fm_ec *)(fm_raw + fm_pos);
699 		fm_pos += sizeof(*fmec);
700 		if (fm_pos >= fm_size)
701 			goto fail_bad;
702 
703 		add_aeb(ai, &used, be32_to_cpu(fmec->pnum),
704 			be32_to_cpu(fmec->ec), 0);
705 	}
706 
707 	/* read EC values from scrub list */
708 	for (i = 0; i < be32_to_cpu(fmhdr->scrub_peb_count); i++) {
709 		fmec = (struct ubi_fm_ec *)(fm_raw + fm_pos);
710 		fm_pos += sizeof(*fmec);
711 		if (fm_pos >= fm_size)
712 			goto fail_bad;
713 
714 		add_aeb(ai, &used, be32_to_cpu(fmec->pnum),
715 			be32_to_cpu(fmec->ec), 1);
716 	}
717 
718 	/* read EC values from erase list */
719 	for (i = 0; i < be32_to_cpu(fmhdr->erase_peb_count); i++) {
720 		fmec = (struct ubi_fm_ec *)(fm_raw + fm_pos);
721 		fm_pos += sizeof(*fmec);
722 		if (fm_pos >= fm_size)
723 			goto fail_bad;
724 
725 		add_aeb(ai, &ai->erase, be32_to_cpu(fmec->pnum),
726 			be32_to_cpu(fmec->ec), 1);
727 	}
728 
729 	ai->mean_ec = div_u64(ai->ec_sum, ai->ec_count);
730 	ai->bad_peb_count = be32_to_cpu(fmhdr->bad_peb_count);
731 
732 	/* Iterate over all volumes and read their EBA table */
733 	for (i = 0; i < be32_to_cpu(fmhdr->vol_count); i++) {
734 		fmvhdr = (struct ubi_fm_volhdr *)(fm_raw + fm_pos);
735 		fm_pos += sizeof(*fmvhdr);
736 		if (fm_pos >= fm_size)
737 			goto fail_bad;
738 
739 		if (be32_to_cpu(fmvhdr->magic) != UBI_FM_VHDR_MAGIC) {
740 			ubi_err(ubi, "bad fastmap vol header magic: 0x%x, expected: 0x%x",
741 				be32_to_cpu(fmvhdr->magic), UBI_FM_VHDR_MAGIC);
742 			goto fail_bad;
743 		}
744 
745 		av = add_vol(ai, be32_to_cpu(fmvhdr->vol_id),
746 			     be32_to_cpu(fmvhdr->used_ebs),
747 			     be32_to_cpu(fmvhdr->data_pad),
748 			     fmvhdr->vol_type,
749 			     be32_to_cpu(fmvhdr->last_eb_bytes));
750 
751 		if (!av)
752 			goto fail_bad;
753 		if (PTR_ERR(av) == -EINVAL) {
754 			ubi_err(ubi, "volume (ID %i) already exists",
755 				fmvhdr->vol_id);
756 			goto fail_bad;
757 		}
758 
759 		ai->vols_found++;
760 		if (ai->highest_vol_id < be32_to_cpu(fmvhdr->vol_id))
761 			ai->highest_vol_id = be32_to_cpu(fmvhdr->vol_id);
762 
763 		fm_eba = (struct ubi_fm_eba *)(fm_raw + fm_pos);
764 		fm_pos += sizeof(*fm_eba);
765 		fm_pos += (sizeof(__be32) * be32_to_cpu(fm_eba->reserved_pebs));
766 		if (fm_pos >= fm_size)
767 			goto fail_bad;
768 
769 		if (be32_to_cpu(fm_eba->magic) != UBI_FM_EBA_MAGIC) {
770 			ubi_err(ubi, "bad fastmap EBA header magic: 0x%x, expected: 0x%x",
771 				be32_to_cpu(fm_eba->magic), UBI_FM_EBA_MAGIC);
772 			goto fail_bad;
773 		}
774 
775 		for (j = 0; j < be32_to_cpu(fm_eba->reserved_pebs); j++) {
776 			int pnum = be32_to_cpu(fm_eba->pnum[j]);
777 
778 			if (pnum < 0)
779 				continue;
780 
781 			aeb = NULL;
782 			list_for_each_entry(tmp_aeb, &used, u.list) {
783 				if (tmp_aeb->pnum == pnum) {
784 					aeb = tmp_aeb;
785 					break;
786 				}
787 			}
788 
789 			if (!aeb) {
790 				ubi_err(ubi, "PEB %i is in EBA but not in used list", pnum);
791 				goto fail_bad;
792 			}
793 
794 			aeb->lnum = j;
795 
796 			if (av->highest_lnum <= aeb->lnum)
797 				av->highest_lnum = aeb->lnum;
798 
799 			assign_aeb_to_av(ai, aeb, av);
800 
801 			dbg_bld("inserting PEB:%i (LEB %i) to vol %i",
802 				aeb->pnum, aeb->lnum, av->vol_id);
803 		}
804 	}
805 
806 	ret = scan_pool(ubi, ai, fmpl->pebs, pool_size, &max_sqnum, &free);
807 	if (ret)
808 		goto fail;
809 
810 	ret = scan_pool(ubi, ai, fmpl_wl->pebs, wl_pool_size, &max_sqnum, &free);
811 	if (ret)
812 		goto fail;
813 
814 	if (max_sqnum > ai->max_sqnum)
815 		ai->max_sqnum = max_sqnum;
816 
817 	list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &free, u.list)
818 		list_move_tail(&tmp_aeb->u.list, &ai->free);
819 
820 	list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &used, u.list)
821 		list_move_tail(&tmp_aeb->u.list, &ai->erase);
822 
823 	ubi_assert(list_empty(&free));
824 
825 	/*
826 	 * If fastmap is leaking PEBs (must not happen), raise a
827 	 * fat warning and fall back to scanning mode.
828 	 * We do this here because in ubi_wl_init() it's too late
829 	 * and we cannot fall back to scanning.
830 	 */
831 	if (WARN_ON(count_fastmap_pebs(ai) != ubi->peb_count -
832 		    ai->bad_peb_count - fm->used_blocks))
833 		goto fail_bad;
834 
835 	return 0;
836 
837 fail_bad:
838 	ret = UBI_BAD_FASTMAP;
839 fail:
840 	list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &used, u.list) {
841 		list_del(&tmp_aeb->u.list);
842 		kmem_cache_free(ai->aeb_slab_cache, tmp_aeb);
843 	}
844 	list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &free, u.list) {
845 		list_del(&tmp_aeb->u.list);
846 		kmem_cache_free(ai->aeb_slab_cache, tmp_aeb);
847 	}
848 
849 	return ret;
850 }
851 
852 /**
853  * ubi_scan_fastmap - scan the fastmap.
854  * @ubi: UBI device object
855  * @ai: UBI attach info to be filled
856  * @fm_anchor: The fastmap starts at this PEB
857  *
858  * Returns 0 on success, UBI_NO_FASTMAP if no fastmap was found,
859  * UBI_BAD_FASTMAP if one was found but is not usable.
860  * < 0 indicates an internal error.
861  */
862 int ubi_scan_fastmap(struct ubi_device *ubi, struct ubi_attach_info *ai,
863 		     int fm_anchor)
864 {
865 	struct ubi_fm_sb *fmsb, *fmsb2;
866 	struct ubi_vid_hdr *vh;
867 	struct ubi_ec_hdr *ech;
868 	struct ubi_fastmap_layout *fm;
869 	int i, used_blocks, pnum, ret = 0;
870 	size_t fm_size;
871 	__be32 crc, tmp_crc;
872 	unsigned long long sqnum = 0;
873 
874 	down_write(&ubi->fm_protect);
875 	memset(ubi->fm_buf, 0, ubi->fm_size);
876 
877 	fmsb = kmalloc(sizeof(*fmsb), GFP_KERNEL);
878 	if (!fmsb) {
879 		ret = -ENOMEM;
880 		goto out;
881 	}
882 
883 	fm = kzalloc(sizeof(*fm), GFP_KERNEL);
884 	if (!fm) {
885 		ret = -ENOMEM;
886 		kfree(fmsb);
887 		goto out;
888 	}
889 
890 	ret = ubi_io_read(ubi, fmsb, fm_anchor, ubi->leb_start, sizeof(*fmsb));
891 	if (ret && ret != UBI_IO_BITFLIPS)
892 		goto free_fm_sb;
893 	else if (ret == UBI_IO_BITFLIPS)
894 		fm->to_be_tortured[0] = 1;
895 
896 	if (be32_to_cpu(fmsb->magic) != UBI_FM_SB_MAGIC) {
897 		ubi_err(ubi, "bad super block magic: 0x%x, expected: 0x%x",
898 			be32_to_cpu(fmsb->magic), UBI_FM_SB_MAGIC);
899 		ret = UBI_BAD_FASTMAP;
900 		goto free_fm_sb;
901 	}
902 
903 	if (fmsb->version != UBI_FM_FMT_VERSION) {
904 		ubi_err(ubi, "bad fastmap version: %i, expected: %i",
905 			fmsb->version, UBI_FM_FMT_VERSION);
906 		ret = UBI_BAD_FASTMAP;
907 		goto free_fm_sb;
908 	}
909 
910 	used_blocks = be32_to_cpu(fmsb->used_blocks);
911 	if (used_blocks > UBI_FM_MAX_BLOCKS || used_blocks < 1) {
912 		ubi_err(ubi, "number of fastmap blocks is invalid: %i",
913 			used_blocks);
914 		ret = UBI_BAD_FASTMAP;
915 		goto free_fm_sb;
916 	}
917 
918 	fm_size = ubi->leb_size * used_blocks;
919 	if (fm_size != ubi->fm_size) {
920 		ubi_err(ubi, "bad fastmap size: %zi, expected: %zi",
921 			fm_size, ubi->fm_size);
922 		ret = UBI_BAD_FASTMAP;
923 		goto free_fm_sb;
924 	}
925 
926 	ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
927 	if (!ech) {
928 		ret = -ENOMEM;
929 		goto free_fm_sb;
930 	}
931 
932 	vh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
933 	if (!vh) {
934 		ret = -ENOMEM;
935 		goto free_hdr;
936 	}
937 
938 	for (i = 0; i < used_blocks; i++) {
939 		int image_seq;
940 
941 		pnum = be32_to_cpu(fmsb->block_loc[i]);
942 
943 		if (ubi_io_is_bad(ubi, pnum)) {
944 			ret = UBI_BAD_FASTMAP;
945 			goto free_hdr;
946 		}
947 
948 		ret = ubi_io_read_ec_hdr(ubi, pnum, ech, 0);
949 		if (ret && ret != UBI_IO_BITFLIPS) {
950 			ubi_err(ubi, "unable to read fastmap block# %i EC (PEB: %i)",
951 				i, pnum);
952 			if (ret > 0)
953 				ret = UBI_BAD_FASTMAP;
954 			goto free_hdr;
955 		} else if (ret == UBI_IO_BITFLIPS)
956 			fm->to_be_tortured[i] = 1;
957 
958 		image_seq = be32_to_cpu(ech->image_seq);
959 		if (!ubi->image_seq)
960 			ubi->image_seq = image_seq;
961 
962 		/*
963 		 * Older UBI implementations have image_seq set to zero, so
964 		 * we shouldn't fail if image_seq == 0.
965 		 */
966 		if (image_seq && (image_seq != ubi->image_seq)) {
967 			ubi_err(ubi, "wrong image seq:%d instead of %d",
968 				be32_to_cpu(ech->image_seq), ubi->image_seq);
969 			ret = UBI_BAD_FASTMAP;
970 			goto free_hdr;
971 		}
972 
973 		ret = ubi_io_read_vid_hdr(ubi, pnum, vh, 0);
974 		if (ret && ret != UBI_IO_BITFLIPS) {
975 			ubi_err(ubi, "unable to read fastmap block# %i (PEB: %i)",
976 				i, pnum);
977 			goto free_hdr;
978 		}
979 
980 		if (i == 0) {
981 			if (be32_to_cpu(vh->vol_id) != UBI_FM_SB_VOLUME_ID) {
982 				ubi_err(ubi, "bad fastmap anchor vol_id: 0x%x, expected: 0x%x",
983 					be32_to_cpu(vh->vol_id),
984 					UBI_FM_SB_VOLUME_ID);
985 				ret = UBI_BAD_FASTMAP;
986 				goto free_hdr;
987 			}
988 		} else {
989 			if (be32_to_cpu(vh->vol_id) != UBI_FM_DATA_VOLUME_ID) {
990 				ubi_err(ubi, "bad fastmap data vol_id: 0x%x, expected: 0x%x",
991 					be32_to_cpu(vh->vol_id),
992 					UBI_FM_DATA_VOLUME_ID);
993 				ret = UBI_BAD_FASTMAP;
994 				goto free_hdr;
995 			}
996 		}
997 
998 		if (sqnum < be64_to_cpu(vh->sqnum))
999 			sqnum = be64_to_cpu(vh->sqnum);
1000 
1001 		ret = ubi_io_read(ubi, ubi->fm_buf + (ubi->leb_size * i), pnum,
1002 				  ubi->leb_start, ubi->leb_size);
1003 		if (ret && ret != UBI_IO_BITFLIPS) {
1004 			ubi_err(ubi, "unable to read fastmap block# %i (PEB: %i, "
1005 				"err: %i)", i, pnum, ret);
1006 			goto free_hdr;
1007 		}
1008 	}
1009 
1010 	kfree(fmsb);
1011 	fmsb = NULL;
1012 
1013 	fmsb2 = (struct ubi_fm_sb *)(ubi->fm_buf);
1014 	tmp_crc = be32_to_cpu(fmsb2->data_crc);
1015 	fmsb2->data_crc = 0;
1016 	crc = crc32(UBI_CRC32_INIT, ubi->fm_buf, fm_size);
1017 	if (crc != tmp_crc) {
1018 		ubi_err(ubi, "fastmap data CRC is invalid");
1019 		ubi_err(ubi, "CRC should be: 0x%x, calc: 0x%x",
1020 			tmp_crc, crc);
1021 		ret = UBI_BAD_FASTMAP;
1022 		goto free_hdr;
1023 	}
1024 
1025 	fmsb2->sqnum = sqnum;
1026 
1027 	fm->used_blocks = used_blocks;
1028 
1029 	ret = ubi_attach_fastmap(ubi, ai, fm);
1030 	if (ret) {
1031 		if (ret > 0)
1032 			ret = UBI_BAD_FASTMAP;
1033 		goto free_hdr;
1034 	}
1035 
1036 	for (i = 0; i < used_blocks; i++) {
1037 		struct ubi_wl_entry *e;
1038 
1039 		e = kmem_cache_alloc(ubi_wl_entry_slab, GFP_KERNEL);
1040 		if (!e) {
1041 			while (i--)
1042 				kfree(fm->e[i]);
1043 
1044 			ret = -ENOMEM;
1045 			goto free_hdr;
1046 		}
1047 
1048 		e->pnum = be32_to_cpu(fmsb2->block_loc[i]);
1049 		e->ec = be32_to_cpu(fmsb2->block_ec[i]);
1050 		fm->e[i] = e;
1051 	}
1052 
1053 	ubi->fm = fm;
1054 	ubi->fm_pool.max_size = ubi->fm->max_pool_size;
1055 	ubi->fm_wl_pool.max_size = ubi->fm->max_wl_pool_size;
1056 	ubi_msg(ubi, "attached by fastmap");
1057 	ubi_msg(ubi, "fastmap pool size: %d", ubi->fm_pool.max_size);
1058 	ubi_msg(ubi, "fastmap WL pool size: %d",
1059 		ubi->fm_wl_pool.max_size);
1060 	ubi->fm_disabled = 0;
1061 	ubi->fast_attach = 1;
1062 
1063 	ubi_free_vid_hdr(ubi, vh);
1064 	kfree(ech);
1065 out:
1066 	up_write(&ubi->fm_protect);
1067 	if (ret == UBI_BAD_FASTMAP)
1068 		ubi_err(ubi, "Attach by fastmap failed, doing a full scan!");
1069 	return ret;
1070 
1071 free_hdr:
1072 	ubi_free_vid_hdr(ubi, vh);
1073 	kfree(ech);
1074 free_fm_sb:
1075 	kfree(fmsb);
1076 	kfree(fm);
1077 	goto out;
1078 }
1079 
1080 /**
1081  * ubi_write_fastmap - writes a fastmap.
1082  * @ubi: UBI device object
1083  * @new_fm: the to be written fastmap
1084  *
1085  * Returns 0 on success, < 0 indicates an internal error.
1086  */
1087 static int ubi_write_fastmap(struct ubi_device *ubi,
1088 			     struct ubi_fastmap_layout *new_fm)
1089 {
1090 	size_t fm_pos = 0;
1091 	void *fm_raw;
1092 	struct ubi_fm_sb *fmsb;
1093 	struct ubi_fm_hdr *fmh;
1094 	struct ubi_fm_scan_pool *fmpl, *fmpl_wl;
1095 	struct ubi_fm_ec *fec;
1096 	struct ubi_fm_volhdr *fvh;
1097 	struct ubi_fm_eba *feba;
1098 	struct ubi_wl_entry *wl_e;
1099 	struct ubi_volume *vol;
1100 	struct ubi_vid_hdr *avhdr, *dvhdr;
1101 	struct ubi_work *ubi_wrk;
1102 	struct rb_node *tmp_rb;
1103 	int ret, i, j, free_peb_count, used_peb_count, vol_count;
1104 	int scrub_peb_count, erase_peb_count;
1105 	int *seen_pebs = NULL;
1106 
1107 	fm_raw = ubi->fm_buf;
1108 	memset(ubi->fm_buf, 0, ubi->fm_size);
1109 
1110 	avhdr = new_fm_vhdr(ubi, UBI_FM_SB_VOLUME_ID);
1111 	if (!avhdr) {
1112 		ret = -ENOMEM;
1113 		goto out;
1114 	}
1115 
1116 	dvhdr = new_fm_vhdr(ubi, UBI_FM_DATA_VOLUME_ID);
1117 	if (!dvhdr) {
1118 		ret = -ENOMEM;
1119 		goto out_kfree;
1120 	}
1121 
1122 	seen_pebs = init_seen(ubi);
1123 	if (IS_ERR(seen_pebs)) {
1124 		ret = PTR_ERR(seen_pebs);
1125 		goto out_kfree;
1126 	}
1127 
1128 	spin_lock(&ubi->volumes_lock);
1129 	spin_lock(&ubi->wl_lock);
1130 
1131 	fmsb = (struct ubi_fm_sb *)fm_raw;
1132 	fm_pos += sizeof(*fmsb);
1133 	ubi_assert(fm_pos <= ubi->fm_size);
1134 
1135 	fmh = (struct ubi_fm_hdr *)(fm_raw + fm_pos);
1136 	fm_pos += sizeof(*fmh);
1137 	ubi_assert(fm_pos <= ubi->fm_size);
1138 
1139 	fmsb->magic = cpu_to_be32(UBI_FM_SB_MAGIC);
1140 	fmsb->version = UBI_FM_FMT_VERSION;
1141 	fmsb->used_blocks = cpu_to_be32(new_fm->used_blocks);
1142 	/* the max sqnum will be filled in while *reading* the fastmap */
1143 	fmsb->sqnum = 0;
1144 
1145 	fmh->magic = cpu_to_be32(UBI_FM_HDR_MAGIC);
1146 	free_peb_count = 0;
1147 	used_peb_count = 0;
1148 	scrub_peb_count = 0;
1149 	erase_peb_count = 0;
1150 	vol_count = 0;
1151 
1152 	fmpl = (struct ubi_fm_scan_pool *)(fm_raw + fm_pos);
1153 	fm_pos += sizeof(*fmpl);
1154 	fmpl->magic = cpu_to_be32(UBI_FM_POOL_MAGIC);
1155 	fmpl->size = cpu_to_be16(ubi->fm_pool.size);
1156 	fmpl->max_size = cpu_to_be16(ubi->fm_pool.max_size);
1157 
1158 	for (i = 0; i < ubi->fm_pool.size; i++) {
1159 		fmpl->pebs[i] = cpu_to_be32(ubi->fm_pool.pebs[i]);
1160 		set_seen(ubi, ubi->fm_pool.pebs[i], seen_pebs);
1161 	}
1162 
1163 	fmpl_wl = (struct ubi_fm_scan_pool *)(fm_raw + fm_pos);
1164 	fm_pos += sizeof(*fmpl_wl);
1165 	fmpl_wl->magic = cpu_to_be32(UBI_FM_POOL_MAGIC);
1166 	fmpl_wl->size = cpu_to_be16(ubi->fm_wl_pool.size);
1167 	fmpl_wl->max_size = cpu_to_be16(ubi->fm_wl_pool.max_size);
1168 
1169 	for (i = 0; i < ubi->fm_wl_pool.size; i++) {
1170 		fmpl_wl->pebs[i] = cpu_to_be32(ubi->fm_wl_pool.pebs[i]);
1171 		set_seen(ubi, ubi->fm_wl_pool.pebs[i], seen_pebs);
1172 	}
1173 
1174 	ubi_for_each_free_peb(ubi, wl_e, tmp_rb) {
1175 		fec = (struct ubi_fm_ec *)(fm_raw + fm_pos);
1176 
1177 		fec->pnum = cpu_to_be32(wl_e->pnum);
1178 		set_seen(ubi, wl_e->pnum, seen_pebs);
1179 		fec->ec = cpu_to_be32(wl_e->ec);
1180 
1181 		free_peb_count++;
1182 		fm_pos += sizeof(*fec);
1183 		ubi_assert(fm_pos <= ubi->fm_size);
1184 	}
1185 	fmh->free_peb_count = cpu_to_be32(free_peb_count);
1186 
1187 	ubi_for_each_used_peb(ubi, wl_e, tmp_rb) {
1188 		fec = (struct ubi_fm_ec *)(fm_raw + fm_pos);
1189 
1190 		fec->pnum = cpu_to_be32(wl_e->pnum);
1191 		set_seen(ubi, wl_e->pnum, seen_pebs);
1192 		fec->ec = cpu_to_be32(wl_e->ec);
1193 
1194 		used_peb_count++;
1195 		fm_pos += sizeof(*fec);
1196 		ubi_assert(fm_pos <= ubi->fm_size);
1197 	}
1198 
1199 	ubi_for_each_protected_peb(ubi, i, wl_e) {
1200 		fec = (struct ubi_fm_ec *)(fm_raw + fm_pos);
1201 
1202 		fec->pnum = cpu_to_be32(wl_e->pnum);
1203 		set_seen(ubi, wl_e->pnum, seen_pebs);
1204 		fec->ec = cpu_to_be32(wl_e->ec);
1205 
1206 		used_peb_count++;
1207 		fm_pos += sizeof(*fec);
1208 		ubi_assert(fm_pos <= ubi->fm_size);
1209 	}
1210 	fmh->used_peb_count = cpu_to_be32(used_peb_count);
1211 
1212 	ubi_for_each_scrub_peb(ubi, wl_e, tmp_rb) {
1213 		fec = (struct ubi_fm_ec *)(fm_raw + fm_pos);
1214 
1215 		fec->pnum = cpu_to_be32(wl_e->pnum);
1216 		set_seen(ubi, wl_e->pnum, seen_pebs);
1217 		fec->ec = cpu_to_be32(wl_e->ec);
1218 
1219 		scrub_peb_count++;
1220 		fm_pos += sizeof(*fec);
1221 		ubi_assert(fm_pos <= ubi->fm_size);
1222 	}
1223 	fmh->scrub_peb_count = cpu_to_be32(scrub_peb_count);
1224 
1225 
1226 	list_for_each_entry(ubi_wrk, &ubi->works, list) {
1227 		if (ubi_is_erase_work(ubi_wrk)) {
1228 			wl_e = ubi_wrk->e;
1229 			ubi_assert(wl_e);
1230 
1231 			fec = (struct ubi_fm_ec *)(fm_raw + fm_pos);
1232 
1233 			fec->pnum = cpu_to_be32(wl_e->pnum);
1234 			set_seen(ubi, wl_e->pnum, seen_pebs);
1235 			fec->ec = cpu_to_be32(wl_e->ec);
1236 
1237 			erase_peb_count++;
1238 			fm_pos += sizeof(*fec);
1239 			ubi_assert(fm_pos <= ubi->fm_size);
1240 		}
1241 	}
1242 	fmh->erase_peb_count = cpu_to_be32(erase_peb_count);
1243 
1244 	for (i = 0; i < UBI_MAX_VOLUMES + UBI_INT_VOL_COUNT; i++) {
1245 		vol = ubi->volumes[i];
1246 
1247 		if (!vol)
1248 			continue;
1249 
1250 		vol_count++;
1251 
1252 		fvh = (struct ubi_fm_volhdr *)(fm_raw + fm_pos);
1253 		fm_pos += sizeof(*fvh);
1254 		ubi_assert(fm_pos <= ubi->fm_size);
1255 
1256 		fvh->magic = cpu_to_be32(UBI_FM_VHDR_MAGIC);
1257 		fvh->vol_id = cpu_to_be32(vol->vol_id);
1258 		fvh->vol_type = vol->vol_type;
1259 		fvh->used_ebs = cpu_to_be32(vol->used_ebs);
1260 		fvh->data_pad = cpu_to_be32(vol->data_pad);
1261 		fvh->last_eb_bytes = cpu_to_be32(vol->last_eb_bytes);
1262 
1263 		ubi_assert(vol->vol_type == UBI_DYNAMIC_VOLUME ||
1264 			vol->vol_type == UBI_STATIC_VOLUME);
1265 
1266 		feba = (struct ubi_fm_eba *)(fm_raw + fm_pos);
1267 		fm_pos += sizeof(*feba) + (sizeof(__be32) * vol->reserved_pebs);
1268 		ubi_assert(fm_pos <= ubi->fm_size);
1269 
1270 		for (j = 0; j < vol->reserved_pebs; j++)
1271 			feba->pnum[j] = cpu_to_be32(vol->eba_tbl[j]);
1272 
1273 		feba->reserved_pebs = cpu_to_be32(j);
1274 		feba->magic = cpu_to_be32(UBI_FM_EBA_MAGIC);
1275 	}
1276 	fmh->vol_count = cpu_to_be32(vol_count);
1277 	fmh->bad_peb_count = cpu_to_be32(ubi->bad_peb_count);
1278 
1279 	avhdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
1280 	avhdr->lnum = 0;
1281 
1282 	spin_unlock(&ubi->wl_lock);
1283 	spin_unlock(&ubi->volumes_lock);
1284 
1285 	dbg_bld("writing fastmap SB to PEB %i", new_fm->e[0]->pnum);
1286 	ret = ubi_io_write_vid_hdr(ubi, new_fm->e[0]->pnum, avhdr);
1287 	if (ret) {
1288 		ubi_err(ubi, "unable to write vid_hdr to fastmap SB!");
1289 		goto out_kfree;
1290 	}
1291 
1292 	for (i = 0; i < new_fm->used_blocks; i++) {
1293 		fmsb->block_loc[i] = cpu_to_be32(new_fm->e[i]->pnum);
1294 		set_seen(ubi, new_fm->e[i]->pnum, seen_pebs);
1295 		fmsb->block_ec[i] = cpu_to_be32(new_fm->e[i]->ec);
1296 	}
1297 
1298 	fmsb->data_crc = 0;
1299 	fmsb->data_crc = cpu_to_be32(crc32(UBI_CRC32_INIT, fm_raw,
1300 					   ubi->fm_size));
1301 
1302 	for (i = 1; i < new_fm->used_blocks; i++) {
1303 		dvhdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
1304 		dvhdr->lnum = cpu_to_be32(i);
1305 		dbg_bld("writing fastmap data to PEB %i sqnum %llu",
1306 			new_fm->e[i]->pnum, be64_to_cpu(dvhdr->sqnum));
1307 		ret = ubi_io_write_vid_hdr(ubi, new_fm->e[i]->pnum, dvhdr);
1308 		if (ret) {
1309 			ubi_err(ubi, "unable to write vid_hdr to PEB %i!",
1310 				new_fm->e[i]->pnum);
1311 			goto out_kfree;
1312 		}
1313 	}
1314 
1315 	for (i = 0; i < new_fm->used_blocks; i++) {
1316 		ret = ubi_io_write(ubi, fm_raw + (i * ubi->leb_size),
1317 			new_fm->e[i]->pnum, ubi->leb_start, ubi->leb_size);
1318 		if (ret) {
1319 			ubi_err(ubi, "unable to write fastmap to PEB %i!",
1320 				new_fm->e[i]->pnum);
1321 			goto out_kfree;
1322 		}
1323 	}
1324 
1325 	ubi_assert(new_fm);
1326 	ubi->fm = new_fm;
1327 
1328 	ret = self_check_seen(ubi, seen_pebs);
1329 	dbg_bld("fastmap written!");
1330 
1331 out_kfree:
1332 	ubi_free_vid_hdr(ubi, avhdr);
1333 	ubi_free_vid_hdr(ubi, dvhdr);
1334 	free_seen(seen_pebs);
1335 out:
1336 	return ret;
1337 }
1338 
1339 /**
1340  * erase_block - Manually erase a PEB.
1341  * @ubi: UBI device object
1342  * @pnum: PEB to be erased
1343  *
1344  * Returns the new EC value on success, < 0 indicates an internal error.
1345  */
1346 static int erase_block(struct ubi_device *ubi, int pnum)
1347 {
1348 	int ret;
1349 	struct ubi_ec_hdr *ec_hdr;
1350 	long long ec;
1351 
1352 	ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
1353 	if (!ec_hdr)
1354 		return -ENOMEM;
1355 
1356 	ret = ubi_io_read_ec_hdr(ubi, pnum, ec_hdr, 0);
1357 	if (ret < 0)
1358 		goto out;
1359 	else if (ret && ret != UBI_IO_BITFLIPS) {
1360 		ret = -EINVAL;
1361 		goto out;
1362 	}
1363 
1364 	ret = ubi_io_sync_erase(ubi, pnum, 0);
1365 	if (ret < 0)
1366 		goto out;
1367 
1368 	ec = be64_to_cpu(ec_hdr->ec);
1369 	ec += ret;
1370 	if (ec > UBI_MAX_ERASECOUNTER) {
1371 		ret = -EINVAL;
1372 		goto out;
1373 	}
1374 
1375 	ec_hdr->ec = cpu_to_be64(ec);
1376 	ret = ubi_io_write_ec_hdr(ubi, pnum, ec_hdr);
1377 	if (ret < 0)
1378 		goto out;
1379 
1380 	ret = ec;
1381 out:
1382 	kfree(ec_hdr);
1383 	return ret;
1384 }
1385 
1386 /**
1387  * invalidate_fastmap - destroys a fastmap.
1388  * @ubi: UBI device object
1389  *
1390  * This function ensures that upon next UBI attach a full scan
1391  * is issued. We need this if UBI is about to write a new fastmap
1392  * but is unable to do so. In this case we have two options:
1393  * a) Make sure that the current fastmap will not be usued upon
1394  * attach time and contine or b) fall back to RO mode to have the
1395  * current fastmap in a valid state.
1396  * Returns 0 on success, < 0 indicates an internal error.
1397  */
1398 static int invalidate_fastmap(struct ubi_device *ubi)
1399 {
1400 	int ret;
1401 	struct ubi_fastmap_layout *fm;
1402 	struct ubi_wl_entry *e;
1403 	struct ubi_vid_hdr *vh = NULL;
1404 
1405 	if (!ubi->fm)
1406 		return 0;
1407 
1408 	ubi->fm = NULL;
1409 
1410 	ret = -ENOMEM;
1411 	fm = kzalloc(sizeof(*fm), GFP_KERNEL);
1412 	if (!fm)
1413 		goto out;
1414 
1415 	vh = new_fm_vhdr(ubi, UBI_FM_SB_VOLUME_ID);
1416 	if (!vh)
1417 		goto out_free_fm;
1418 
1419 	ret = -ENOSPC;
1420 	e = ubi_wl_get_fm_peb(ubi, 1);
1421 	if (!e)
1422 		goto out_free_fm;
1423 
1424 	/*
1425 	 * Create fake fastmap such that UBI will fall back
1426 	 * to scanning mode.
1427 	 */
1428 	vh->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
1429 	ret = ubi_io_write_vid_hdr(ubi, e->pnum, vh);
1430 	if (ret < 0) {
1431 		ubi_wl_put_fm_peb(ubi, e, 0, 0);
1432 		goto out_free_fm;
1433 	}
1434 
1435 	fm->used_blocks = 1;
1436 	fm->e[0] = e;
1437 
1438 	ubi->fm = fm;
1439 
1440 out:
1441 	ubi_free_vid_hdr(ubi, vh);
1442 	return ret;
1443 
1444 out_free_fm:
1445 	kfree(fm);
1446 	goto out;
1447 }
1448 
1449 /**
1450  * return_fm_pebs - returns all PEBs used by a fastmap back to the
1451  * WL sub-system.
1452  * @ubi: UBI device object
1453  * @fm: fastmap layout object
1454  */
1455 static void return_fm_pebs(struct ubi_device *ubi,
1456 			   struct ubi_fastmap_layout *fm)
1457 {
1458 	int i;
1459 
1460 	if (!fm)
1461 		return;
1462 
1463 	for (i = 0; i < fm->used_blocks; i++) {
1464 		if (fm->e[i]) {
1465 			ubi_wl_put_fm_peb(ubi, fm->e[i], i,
1466 					  fm->to_be_tortured[i]);
1467 			fm->e[i] = NULL;
1468 		}
1469 	}
1470 }
1471 
1472 /**
1473  * ubi_update_fastmap - will be called by UBI if a volume changes or
1474  * a fastmap pool becomes full.
1475  * @ubi: UBI device object
1476  *
1477  * Returns 0 on success, < 0 indicates an internal error.
1478  */
1479 int ubi_update_fastmap(struct ubi_device *ubi)
1480 {
1481 	int ret, i, j;
1482 	struct ubi_fastmap_layout *new_fm, *old_fm;
1483 	struct ubi_wl_entry *tmp_e;
1484 
1485 	down_write(&ubi->fm_protect);
1486 
1487 	ubi_refill_pools(ubi);
1488 
1489 	if (ubi->ro_mode || ubi->fm_disabled) {
1490 		up_write(&ubi->fm_protect);
1491 		return 0;
1492 	}
1493 
1494 	ret = ubi_ensure_anchor_pebs(ubi);
1495 	if (ret) {
1496 		up_write(&ubi->fm_protect);
1497 		return ret;
1498 	}
1499 
1500 	new_fm = kzalloc(sizeof(*new_fm), GFP_KERNEL);
1501 	if (!new_fm) {
1502 		up_write(&ubi->fm_protect);
1503 		return -ENOMEM;
1504 	}
1505 
1506 	new_fm->used_blocks = ubi->fm_size / ubi->leb_size;
1507 	old_fm = ubi->fm;
1508 	ubi->fm = NULL;
1509 
1510 	if (new_fm->used_blocks > UBI_FM_MAX_BLOCKS) {
1511 		ubi_err(ubi, "fastmap too large");
1512 		ret = -ENOSPC;
1513 		goto err;
1514 	}
1515 
1516 	for (i = 1; i < new_fm->used_blocks; i++) {
1517 		spin_lock(&ubi->wl_lock);
1518 		tmp_e = ubi_wl_get_fm_peb(ubi, 0);
1519 		spin_unlock(&ubi->wl_lock);
1520 
1521 		if (!tmp_e) {
1522 			if (old_fm && old_fm->e[i]) {
1523 				ret = erase_block(ubi, old_fm->e[i]->pnum);
1524 				if (ret < 0) {
1525 					ubi_err(ubi, "could not erase old fastmap PEB");
1526 
1527 					for (j = 1; j < i; j++) {
1528 						ubi_wl_put_fm_peb(ubi, new_fm->e[j],
1529 								  j, 0);
1530 						new_fm->e[j] = NULL;
1531 					}
1532 					goto err;
1533 				}
1534 				new_fm->e[i] = old_fm->e[i];
1535 				old_fm->e[i] = NULL;
1536 			} else {
1537 				ubi_err(ubi, "could not get any free erase block");
1538 
1539 				for (j = 1; j < i; j++) {
1540 					ubi_wl_put_fm_peb(ubi, new_fm->e[j], j, 0);
1541 					new_fm->e[j] = NULL;
1542 				}
1543 
1544 				ret = -ENOSPC;
1545 				goto err;
1546 			}
1547 		} else {
1548 			new_fm->e[i] = tmp_e;
1549 
1550 			if (old_fm && old_fm->e[i]) {
1551 				ubi_wl_put_fm_peb(ubi, old_fm->e[i], i,
1552 						  old_fm->to_be_tortured[i]);
1553 				old_fm->e[i] = NULL;
1554 			}
1555 		}
1556 	}
1557 
1558 	/* Old fastmap is larger than the new one */
1559 	if (old_fm && new_fm->used_blocks < old_fm->used_blocks) {
1560 		for (i = new_fm->used_blocks; i < old_fm->used_blocks; i++) {
1561 			ubi_wl_put_fm_peb(ubi, old_fm->e[i], i,
1562 					  old_fm->to_be_tortured[i]);
1563 			old_fm->e[i] = NULL;
1564 		}
1565 	}
1566 
1567 	spin_lock(&ubi->wl_lock);
1568 	tmp_e = ubi_wl_get_fm_peb(ubi, 1);
1569 	spin_unlock(&ubi->wl_lock);
1570 
1571 	if (old_fm) {
1572 		/* no fresh anchor PEB was found, reuse the old one */
1573 		if (!tmp_e) {
1574 			ret = erase_block(ubi, old_fm->e[0]->pnum);
1575 			if (ret < 0) {
1576 				ubi_err(ubi, "could not erase old anchor PEB");
1577 
1578 				for (i = 1; i < new_fm->used_blocks; i++) {
1579 					ubi_wl_put_fm_peb(ubi, new_fm->e[i],
1580 							  i, 0);
1581 					new_fm->e[i] = NULL;
1582 				}
1583 				goto err;
1584 			}
1585 			new_fm->e[0] = old_fm->e[0];
1586 			new_fm->e[0]->ec = ret;
1587 			old_fm->e[0] = NULL;
1588 		} else {
1589 			/* we've got a new anchor PEB, return the old one */
1590 			ubi_wl_put_fm_peb(ubi, old_fm->e[0], 0,
1591 					  old_fm->to_be_tortured[0]);
1592 			new_fm->e[0] = tmp_e;
1593 			old_fm->e[0] = NULL;
1594 		}
1595 	} else {
1596 		if (!tmp_e) {
1597 			ubi_err(ubi, "could not find any anchor PEB");
1598 
1599 			for (i = 1; i < new_fm->used_blocks; i++) {
1600 				ubi_wl_put_fm_peb(ubi, new_fm->e[i], i, 0);
1601 				new_fm->e[i] = NULL;
1602 			}
1603 
1604 			ret = -ENOSPC;
1605 			goto err;
1606 		}
1607 		new_fm->e[0] = tmp_e;
1608 	}
1609 
1610 	down_write(&ubi->work_sem);
1611 	down_write(&ubi->fm_eba_sem);
1612 	ret = ubi_write_fastmap(ubi, new_fm);
1613 	up_write(&ubi->fm_eba_sem);
1614 	up_write(&ubi->work_sem);
1615 
1616 	if (ret)
1617 		goto err;
1618 
1619 out_unlock:
1620 	up_write(&ubi->fm_protect);
1621 	kfree(old_fm);
1622 	return ret;
1623 
1624 err:
1625 	ubi_warn(ubi, "Unable to write new fastmap, err=%i", ret);
1626 
1627 	ret = invalidate_fastmap(ubi);
1628 	if (ret < 0) {
1629 		ubi_err(ubi, "Unable to invalidiate current fastmap!");
1630 		ubi_ro_mode(ubi);
1631 	} else {
1632 		return_fm_pebs(ubi, old_fm);
1633 		return_fm_pebs(ubi, new_fm);
1634 		ret = 0;
1635 	}
1636 
1637 	kfree(new_fm);
1638 	goto out_unlock;
1639 }
1640