1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (c) International Business Machines Corp., 2006
4  * Copyright (c) Nokia Corporation, 2006, 2007
5  *
6  * Author: Artem Bityutskiy (Битюцкий Артём)
7  */
8 
9 /*
10  * This file includes volume table manipulation code. The volume table is an
11  * on-flash table containing volume meta-data like name, number of reserved
12  * physical eraseblocks, type, etc. The volume table is stored in the so-called
13  * "layout volume".
14  *
15  * The layout volume is an internal volume which is organized as follows. It
16  * consists of two logical eraseblocks - LEB 0 and LEB 1. Each logical
17  * eraseblock stores one volume table copy, i.e. LEB 0 and LEB 1 duplicate each
18  * other. This redundancy guarantees robustness to unclean reboots. The volume
19  * table is basically an array of volume table records. Each record contains
20  * full information about the volume and protected by a CRC checksum. Note,
21  * nowadays we use the atomic LEB change operation when updating the volume
22  * table, so we do not really need 2 LEBs anymore, but we preserve the older
23  * design for the backward compatibility reasons.
24  *
25  * When the volume table is changed, it is first changed in RAM. Then LEB 0 is
26  * erased, and the updated volume table is written back to LEB 0. Then same for
27  * LEB 1. This scheme guarantees recoverability from unclean reboots.
28  *
29  * In this UBI implementation the on-flash volume table does not contain any
30  * information about how much data static volumes contain.
31  *
32  * But it would still be beneficial to store this information in the volume
33  * table. For example, suppose we have a static volume X, and all its physical
34  * eraseblocks became bad for some reasons. Suppose we are attaching the
35  * corresponding MTD device, for some reason we find no logical eraseblocks
36  * corresponding to the volume X. According to the volume table volume X does
37  * exist. So we don't know whether it is just empty or all its physical
38  * eraseblocks went bad. So we cannot alarm the user properly.
39  *
40  * The volume table also stores so-called "update marker", which is used for
41  * volume updates. Before updating the volume, the update marker is set, and
42  * after the update operation is finished, the update marker is cleared. So if
43  * the update operation was interrupted (e.g. by an unclean reboot) - the
44  * update marker is still there and we know that the volume's contents is
45  * damaged.
46  */
47 
48 #include <linux/crc32.h>
49 #include <linux/err.h>
50 #include <linux/slab.h>
51 #include <asm/div64.h>
52 #include "ubi.h"
53 
54 static void self_vtbl_check(const struct ubi_device *ubi);
55 
56 /* Empty volume table record */
57 static struct ubi_vtbl_record empty_vtbl_record;
58 
59 /**
60  * ubi_update_layout_vol - helper for updatting layout volumes on flash
61  * @ubi: UBI device description object
62  */
ubi_update_layout_vol(struct ubi_device * ubi)63 static int ubi_update_layout_vol(struct ubi_device *ubi)
64 {
65 	struct ubi_volume *layout_vol;
66 	int i, err;
67 
68 	layout_vol = ubi->volumes[vol_id2idx(ubi, UBI_LAYOUT_VOLUME_ID)];
69 	for (i = 0; i < UBI_LAYOUT_VOLUME_EBS; i++) {
70 		err = ubi_eba_atomic_leb_change(ubi, layout_vol, i, ubi->vtbl,
71 						ubi->vtbl_size);
72 		if (err)
73 			return err;
74 	}
75 
76 	return 0;
77 }
78 
79 /**
80  * ubi_change_vtbl_record - change volume table record.
81  * @ubi: UBI device description object
82  * @idx: table index to change
83  * @vtbl_rec: new volume table record
84  *
85  * This function changes volume table record @idx. If @vtbl_rec is %NULL, empty
86  * volume table record is written. The caller does not have to calculate CRC of
87  * the record as it is done by this function. Returns zero in case of success
88  * and a negative error code in case of failure.
89  */
ubi_change_vtbl_record(struct ubi_device * ubi,int idx,struct ubi_vtbl_record * vtbl_rec)90 int ubi_change_vtbl_record(struct ubi_device *ubi, int idx,
91 			   struct ubi_vtbl_record *vtbl_rec)
92 {
93 	int err;
94 	uint32_t crc;
95 
96 	ubi_assert(idx >= 0 && idx < ubi->vtbl_slots);
97 
98 	if (!vtbl_rec)
99 		vtbl_rec = &empty_vtbl_record;
100 	else {
101 		crc = crc32(UBI_CRC32_INIT, vtbl_rec, UBI_VTBL_RECORD_SIZE_CRC);
102 		vtbl_rec->crc = cpu_to_be32(crc);
103 	}
104 
105 	memcpy(&ubi->vtbl[idx], vtbl_rec, sizeof(struct ubi_vtbl_record));
106 	err = ubi_update_layout_vol(ubi);
107 
108 	self_vtbl_check(ubi);
109 	return err ? err : 0;
110 }
111 
112 /**
113  * ubi_vtbl_rename_volumes - rename UBI volumes in the volume table.
114  * @ubi: UBI device description object
115  * @rename_list: list of &struct ubi_rename_entry objects
116  *
117  * This function re-names multiple volumes specified in @req in the volume
118  * table. Returns zero in case of success and a negative error code in case of
119  * failure.
120  */
ubi_vtbl_rename_volumes(struct ubi_device * ubi,struct list_head * rename_list)121 int ubi_vtbl_rename_volumes(struct ubi_device *ubi,
122 			    struct list_head *rename_list)
123 {
124 	struct ubi_rename_entry *re;
125 
126 	list_for_each_entry(re, rename_list, list) {
127 		uint32_t crc;
128 		struct ubi_volume *vol = re->desc->vol;
129 		struct ubi_vtbl_record *vtbl_rec = &ubi->vtbl[vol->vol_id];
130 
131 		if (re->remove) {
132 			memcpy(vtbl_rec, &empty_vtbl_record,
133 			       sizeof(struct ubi_vtbl_record));
134 			continue;
135 		}
136 
137 		vtbl_rec->name_len = cpu_to_be16(re->new_name_len);
138 		memcpy(vtbl_rec->name, re->new_name, re->new_name_len);
139 		memset(vtbl_rec->name + re->new_name_len, 0,
140 		       UBI_VOL_NAME_MAX + 1 - re->new_name_len);
141 		crc = crc32(UBI_CRC32_INIT, vtbl_rec,
142 			    UBI_VTBL_RECORD_SIZE_CRC);
143 		vtbl_rec->crc = cpu_to_be32(crc);
144 	}
145 
146 	return ubi_update_layout_vol(ubi);
147 }
148 
149 /**
150  * vtbl_check - check if volume table is not corrupted and sensible.
151  * @ubi: UBI device description object
152  * @vtbl: volume table
153  *
154  * This function returns zero if @vtbl is all right, %1 if CRC is incorrect,
155  * and %-EINVAL if it contains inconsistent data.
156  */
vtbl_check(const struct ubi_device * ubi,const struct ubi_vtbl_record * vtbl)157 static int vtbl_check(const struct ubi_device *ubi,
158 		      const struct ubi_vtbl_record *vtbl)
159 {
160 	int i, n, reserved_pebs, alignment, data_pad, vol_type, name_len;
161 	int upd_marker, err;
162 	uint32_t crc;
163 	const char *name;
164 
165 	for (i = 0; i < ubi->vtbl_slots; i++) {
166 		cond_resched();
167 
168 		reserved_pebs = be32_to_cpu(vtbl[i].reserved_pebs);
169 		alignment = be32_to_cpu(vtbl[i].alignment);
170 		data_pad = be32_to_cpu(vtbl[i].data_pad);
171 		upd_marker = vtbl[i].upd_marker;
172 		vol_type = vtbl[i].vol_type;
173 		name_len = be16_to_cpu(vtbl[i].name_len);
174 		name = &vtbl[i].name[0];
175 
176 		crc = crc32(UBI_CRC32_INIT, &vtbl[i], UBI_VTBL_RECORD_SIZE_CRC);
177 		if (be32_to_cpu(vtbl[i].crc) != crc) {
178 			ubi_err(ubi, "bad CRC at record %u: %#08x, not %#08x",
179 				 i, crc, be32_to_cpu(vtbl[i].crc));
180 			ubi_dump_vtbl_record(&vtbl[i], i);
181 			return 1;
182 		}
183 
184 		if (reserved_pebs == 0) {
185 			if (memcmp(&vtbl[i], &empty_vtbl_record,
186 						UBI_VTBL_RECORD_SIZE)) {
187 				err = 2;
188 				goto bad;
189 			}
190 			continue;
191 		}
192 
193 		if (reserved_pebs < 0 || alignment < 0 || data_pad < 0 ||
194 		    name_len < 0) {
195 			err = 3;
196 			goto bad;
197 		}
198 
199 		if (alignment > ubi->leb_size || alignment == 0) {
200 			err = 4;
201 			goto bad;
202 		}
203 
204 		n = alignment & (ubi->min_io_size - 1);
205 		if (alignment != 1 && n) {
206 			err = 5;
207 			goto bad;
208 		}
209 
210 		n = ubi->leb_size % alignment;
211 		if (data_pad != n) {
212 			ubi_err(ubi, "bad data_pad, has to be %d", n);
213 			err = 6;
214 			goto bad;
215 		}
216 
217 		if (vol_type != UBI_VID_DYNAMIC && vol_type != UBI_VID_STATIC) {
218 			err = 7;
219 			goto bad;
220 		}
221 
222 		if (upd_marker != 0 && upd_marker != 1) {
223 			err = 8;
224 			goto bad;
225 		}
226 
227 		if (reserved_pebs > ubi->good_peb_count) {
228 			ubi_err(ubi, "too large reserved_pebs %d, good PEBs %d",
229 				reserved_pebs, ubi->good_peb_count);
230 			err = 9;
231 			goto bad;
232 		}
233 
234 		if (name_len > UBI_VOL_NAME_MAX) {
235 			err = 10;
236 			goto bad;
237 		}
238 
239 		if (name[0] == '\0') {
240 			err = 11;
241 			goto bad;
242 		}
243 
244 		if (name_len != strnlen(name, name_len + 1)) {
245 			err = 12;
246 			goto bad;
247 		}
248 	}
249 
250 	/* Checks that all names are unique */
251 	for (i = 0; i < ubi->vtbl_slots - 1; i++) {
252 		for (n = i + 1; n < ubi->vtbl_slots; n++) {
253 			int len1 = be16_to_cpu(vtbl[i].name_len);
254 			int len2 = be16_to_cpu(vtbl[n].name_len);
255 
256 			if (len1 > 0 && len1 == len2 &&
257 			    !strncmp(vtbl[i].name, vtbl[n].name, len1)) {
258 				ubi_err(ubi, "volumes %d and %d have the same name \"%s\"",
259 					i, n, vtbl[i].name);
260 				ubi_dump_vtbl_record(&vtbl[i], i);
261 				ubi_dump_vtbl_record(&vtbl[n], n);
262 				return -EINVAL;
263 			}
264 		}
265 	}
266 
267 	return 0;
268 
269 bad:
270 	ubi_err(ubi, "volume table check failed: record %d, error %d", i, err);
271 	ubi_dump_vtbl_record(&vtbl[i], i);
272 	return -EINVAL;
273 }
274 
275 /**
276  * create_vtbl - create a copy of volume table.
277  * @ubi: UBI device description object
278  * @ai: attaching information
279  * @copy: number of the volume table copy
280  * @vtbl: contents of the volume table
281  *
282  * This function returns zero in case of success and a negative error code in
283  * case of failure.
284  */
create_vtbl(struct ubi_device * ubi,struct ubi_attach_info * ai,int copy,void * vtbl)285 static int create_vtbl(struct ubi_device *ubi, struct ubi_attach_info *ai,
286 		       int copy, void *vtbl)
287 {
288 	int err, tries = 0;
289 	struct ubi_vid_io_buf *vidb;
290 	struct ubi_vid_hdr *vid_hdr;
291 	struct ubi_ainf_peb *new_aeb;
292 
293 	dbg_gen("create volume table (copy #%d)", copy + 1);
294 
295 	vidb = ubi_alloc_vid_buf(ubi, GFP_KERNEL);
296 	if (!vidb)
297 		return -ENOMEM;
298 
299 	vid_hdr = ubi_get_vid_hdr(vidb);
300 
301 retry:
302 	new_aeb = ubi_early_get_peb(ubi, ai);
303 	if (IS_ERR(new_aeb)) {
304 		err = PTR_ERR(new_aeb);
305 		goto out_free;
306 	}
307 
308 	vid_hdr->vol_type = UBI_LAYOUT_VOLUME_TYPE;
309 	vid_hdr->vol_id = cpu_to_be32(UBI_LAYOUT_VOLUME_ID);
310 	vid_hdr->compat = UBI_LAYOUT_VOLUME_COMPAT;
311 	vid_hdr->data_size = vid_hdr->used_ebs =
312 			     vid_hdr->data_pad = cpu_to_be32(0);
313 	vid_hdr->lnum = cpu_to_be32(copy);
314 	vid_hdr->sqnum = cpu_to_be64(++ai->max_sqnum);
315 
316 	/* The EC header is already there, write the VID header */
317 	err = ubi_io_write_vid_hdr(ubi, new_aeb->pnum, vidb);
318 	if (err)
319 		goto write_error;
320 
321 	/* Write the layout volume contents */
322 	err = ubi_io_write_data(ubi, vtbl, new_aeb->pnum, 0, ubi->vtbl_size);
323 	if (err)
324 		goto write_error;
325 
326 	/*
327 	 * And add it to the attaching information. Don't delete the old version
328 	 * of this LEB as it will be deleted and freed in 'ubi_add_to_av()'.
329 	 */
330 	err = ubi_add_to_av(ubi, ai, new_aeb->pnum, new_aeb->ec, vid_hdr, 0);
331 	ubi_free_aeb(ai, new_aeb);
332 	ubi_free_vid_buf(vidb);
333 	return err;
334 
335 write_error:
336 	if (err == -EIO && ++tries <= 5) {
337 		/*
338 		 * Probably this physical eraseblock went bad, try to pick
339 		 * another one.
340 		 */
341 		list_add(&new_aeb->u.list, &ai->erase);
342 		goto retry;
343 	}
344 	ubi_free_aeb(ai, new_aeb);
345 out_free:
346 	ubi_free_vid_buf(vidb);
347 	return err;
348 
349 }
350 
351 /**
352  * process_lvol - process the layout volume.
353  * @ubi: UBI device description object
354  * @ai: attaching information
355  * @av: layout volume attaching information
356  *
357  * This function is responsible for reading the layout volume, ensuring it is
358  * not corrupted, and recovering from corruptions if needed. Returns volume
359  * table in case of success and a negative error code in case of failure.
360  */
process_lvol(struct ubi_device * ubi,struct ubi_attach_info * ai,struct ubi_ainf_volume * av)361 static struct ubi_vtbl_record *process_lvol(struct ubi_device *ubi,
362 					    struct ubi_attach_info *ai,
363 					    struct ubi_ainf_volume *av)
364 {
365 	int err;
366 	struct rb_node *rb;
367 	struct ubi_ainf_peb *aeb;
368 	struct ubi_vtbl_record *leb[UBI_LAYOUT_VOLUME_EBS] = { NULL, NULL };
369 	int leb_corrupted[UBI_LAYOUT_VOLUME_EBS] = {1, 1};
370 
371 	/*
372 	 * UBI goes through the following steps when it changes the layout
373 	 * volume:
374 	 * a. erase LEB 0;
375 	 * b. write new data to LEB 0;
376 	 * c. erase LEB 1;
377 	 * d. write new data to LEB 1.
378 	 *
379 	 * Before the change, both LEBs contain the same data.
380 	 *
381 	 * Due to unclean reboots, the contents of LEB 0 may be lost, but there
382 	 * should LEB 1. So it is OK if LEB 0 is corrupted while LEB 1 is not.
383 	 * Similarly, LEB 1 may be lost, but there should be LEB 0. And
384 	 * finally, unclean reboots may result in a situation when neither LEB
385 	 * 0 nor LEB 1 are corrupted, but they are different. In this case, LEB
386 	 * 0 contains more recent information.
387 	 *
388 	 * So the plan is to first check LEB 0. Then
389 	 * a. if LEB 0 is OK, it must be containing the most recent data; then
390 	 *    we compare it with LEB 1, and if they are different, we copy LEB
391 	 *    0 to LEB 1;
392 	 * b. if LEB 0 is corrupted, but LEB 1 has to be OK, and we copy LEB 1
393 	 *    to LEB 0.
394 	 */
395 
396 	dbg_gen("check layout volume");
397 
398 	/* Read both LEB 0 and LEB 1 into memory */
399 	ubi_rb_for_each_entry(rb, aeb, &av->root, u.rb) {
400 		leb[aeb->lnum] = vzalloc(ubi->vtbl_size);
401 		if (!leb[aeb->lnum]) {
402 			err = -ENOMEM;
403 			goto out_free;
404 		}
405 
406 		err = ubi_io_read_data(ubi, leb[aeb->lnum], aeb->pnum, 0,
407 				       ubi->vtbl_size);
408 		if (err == UBI_IO_BITFLIPS || mtd_is_eccerr(err))
409 			/*
410 			 * Scrub the PEB later. Note, -EBADMSG indicates an
411 			 * uncorrectable ECC error, but we have our own CRC and
412 			 * the data will be checked later. If the data is OK,
413 			 * the PEB will be scrubbed (because we set
414 			 * aeb->scrub). If the data is not OK, the contents of
415 			 * the PEB will be recovered from the second copy, and
416 			 * aeb->scrub will be cleared in
417 			 * 'ubi_add_to_av()'.
418 			 */
419 			aeb->scrub = 1;
420 		else if (err)
421 			goto out_free;
422 	}
423 
424 	err = -EINVAL;
425 	if (leb[0]) {
426 		leb_corrupted[0] = vtbl_check(ubi, leb[0]);
427 		if (leb_corrupted[0] < 0)
428 			goto out_free;
429 	}
430 
431 	if (!leb_corrupted[0]) {
432 		/* LEB 0 is OK */
433 		if (leb[1])
434 			leb_corrupted[1] = memcmp(leb[0], leb[1],
435 						  ubi->vtbl_size);
436 		if (leb_corrupted[1]) {
437 			ubi_warn(ubi, "volume table copy #2 is corrupted");
438 			err = create_vtbl(ubi, ai, 1, leb[0]);
439 			if (err)
440 				goto out_free;
441 			ubi_msg(ubi, "volume table was restored");
442 		}
443 
444 		/* Both LEB 1 and LEB 2 are OK and consistent */
445 		vfree(leb[1]);
446 		return leb[0];
447 	} else {
448 		/* LEB 0 is corrupted or does not exist */
449 		if (leb[1]) {
450 			leb_corrupted[1] = vtbl_check(ubi, leb[1]);
451 			if (leb_corrupted[1] < 0)
452 				goto out_free;
453 		}
454 		if (leb_corrupted[1]) {
455 			/* Both LEB 0 and LEB 1 are corrupted */
456 			ubi_err(ubi, "both volume tables are corrupted");
457 			goto out_free;
458 		}
459 
460 		ubi_warn(ubi, "volume table copy #1 is corrupted");
461 		err = create_vtbl(ubi, ai, 0, leb[1]);
462 		if (err)
463 			goto out_free;
464 		ubi_msg(ubi, "volume table was restored");
465 
466 		vfree(leb[0]);
467 		return leb[1];
468 	}
469 
470 out_free:
471 	vfree(leb[0]);
472 	vfree(leb[1]);
473 	return ERR_PTR(err);
474 }
475 
476 /**
477  * create_empty_lvol - create empty layout volume.
478  * @ubi: UBI device description object
479  * @ai: attaching information
480  *
481  * This function returns volume table contents in case of success and a
482  * negative error code in case of failure.
483  */
create_empty_lvol(struct ubi_device * ubi,struct ubi_attach_info * ai)484 static struct ubi_vtbl_record *create_empty_lvol(struct ubi_device *ubi,
485 						 struct ubi_attach_info *ai)
486 {
487 	int i;
488 	struct ubi_vtbl_record *vtbl;
489 
490 	vtbl = vzalloc(ubi->vtbl_size);
491 	if (!vtbl)
492 		return ERR_PTR(-ENOMEM);
493 
494 	for (i = 0; i < ubi->vtbl_slots; i++)
495 		memcpy(&vtbl[i], &empty_vtbl_record, UBI_VTBL_RECORD_SIZE);
496 
497 	for (i = 0; i < UBI_LAYOUT_VOLUME_EBS; i++) {
498 		int err;
499 
500 		err = create_vtbl(ubi, ai, i, vtbl);
501 		if (err) {
502 			vfree(vtbl);
503 			return ERR_PTR(err);
504 		}
505 	}
506 
507 	return vtbl;
508 }
509 
510 /**
511  * init_volumes - initialize volume information for existing volumes.
512  * @ubi: UBI device description object
513  * @ai: scanning information
514  * @vtbl: volume table
515  *
516  * This function allocates volume description objects for existing volumes.
517  * Returns zero in case of success and a negative error code in case of
518  * failure.
519  */
init_volumes(struct ubi_device * ubi,const struct ubi_attach_info * ai,const struct ubi_vtbl_record * vtbl)520 static int init_volumes(struct ubi_device *ubi,
521 			const struct ubi_attach_info *ai,
522 			const struct ubi_vtbl_record *vtbl)
523 {
524 	int i, err, reserved_pebs = 0;
525 	struct ubi_ainf_volume *av;
526 	struct ubi_volume *vol;
527 
528 	for (i = 0; i < ubi->vtbl_slots; i++) {
529 		cond_resched();
530 
531 		if (be32_to_cpu(vtbl[i].reserved_pebs) == 0)
532 			continue; /* Empty record */
533 
534 		vol = kzalloc(sizeof(struct ubi_volume), GFP_KERNEL);
535 		if (!vol)
536 			return -ENOMEM;
537 
538 		vol->reserved_pebs = be32_to_cpu(vtbl[i].reserved_pebs);
539 		vol->alignment = be32_to_cpu(vtbl[i].alignment);
540 		vol->data_pad = be32_to_cpu(vtbl[i].data_pad);
541 		vol->upd_marker = vtbl[i].upd_marker;
542 		vol->vol_type = vtbl[i].vol_type == UBI_VID_DYNAMIC ?
543 					UBI_DYNAMIC_VOLUME : UBI_STATIC_VOLUME;
544 		vol->name_len = be16_to_cpu(vtbl[i].name_len);
545 		vol->usable_leb_size = ubi->leb_size - vol->data_pad;
546 		memcpy(vol->name, vtbl[i].name, vol->name_len);
547 		vol->name[vol->name_len] = '\0';
548 		vol->vol_id = i;
549 
550 		if (vtbl[i].flags & UBI_VTBL_SKIP_CRC_CHECK_FLG)
551 			vol->skip_check = 1;
552 
553 		if (vtbl[i].flags & UBI_VTBL_AUTORESIZE_FLG) {
554 			/* Auto re-size flag may be set only for one volume */
555 			if (ubi->autoresize_vol_id != -1) {
556 				ubi_err(ubi, "more than one auto-resize volume (%d and %d)",
557 					ubi->autoresize_vol_id, i);
558 				kfree(vol);
559 				return -EINVAL;
560 			}
561 
562 			ubi->autoresize_vol_id = i;
563 		}
564 
565 		ubi_assert(!ubi->volumes[i]);
566 		ubi->volumes[i] = vol;
567 		ubi->vol_count += 1;
568 		vol->ubi = ubi;
569 		reserved_pebs += vol->reserved_pebs;
570 
571 		/*
572 		 * We use ubi->peb_count and not vol->reserved_pebs because
573 		 * we want to keep the code simple. Otherwise we'd have to
574 		 * resize/check the bitmap upon volume resize too.
575 		 * Allocating a few bytes more does not hurt.
576 		 */
577 		err = ubi_fastmap_init_checkmap(vol, ubi->peb_count);
578 		if (err)
579 			return err;
580 
581 		/*
582 		 * In case of dynamic volume UBI knows nothing about how many
583 		 * data is stored there. So assume the whole volume is used.
584 		 */
585 		if (vol->vol_type == UBI_DYNAMIC_VOLUME) {
586 			vol->used_ebs = vol->reserved_pebs;
587 			vol->last_eb_bytes = vol->usable_leb_size;
588 			vol->used_bytes =
589 				(long long)vol->used_ebs * vol->usable_leb_size;
590 			continue;
591 		}
592 
593 		/* Static volumes only */
594 		av = ubi_find_av(ai, i);
595 		if (!av || !av->leb_count) {
596 			/*
597 			 * No eraseblocks belonging to this volume found. We
598 			 * don't actually know whether this static volume is
599 			 * completely corrupted or just contains no data. And
600 			 * we cannot know this as long as data size is not
601 			 * stored on flash. So we just assume the volume is
602 			 * empty. FIXME: this should be handled.
603 			 */
604 			continue;
605 		}
606 
607 		if (av->leb_count != av->used_ebs) {
608 			/*
609 			 * We found a static volume which misses several
610 			 * eraseblocks. Treat it as corrupted.
611 			 */
612 			ubi_warn(ubi, "static volume %d misses %d LEBs - corrupted",
613 				 av->vol_id, av->used_ebs - av->leb_count);
614 			vol->corrupted = 1;
615 			continue;
616 		}
617 
618 		vol->used_ebs = av->used_ebs;
619 		vol->used_bytes =
620 			(long long)(vol->used_ebs - 1) * vol->usable_leb_size;
621 		vol->used_bytes += av->last_data_size;
622 		vol->last_eb_bytes = av->last_data_size;
623 	}
624 
625 	/* And add the layout volume */
626 	vol = kzalloc(sizeof(struct ubi_volume), GFP_KERNEL);
627 	if (!vol)
628 		return -ENOMEM;
629 
630 	vol->reserved_pebs = UBI_LAYOUT_VOLUME_EBS;
631 	vol->alignment = UBI_LAYOUT_VOLUME_ALIGN;
632 	vol->vol_type = UBI_DYNAMIC_VOLUME;
633 	vol->name_len = sizeof(UBI_LAYOUT_VOLUME_NAME) - 1;
634 	memcpy(vol->name, UBI_LAYOUT_VOLUME_NAME, vol->name_len + 1);
635 	vol->usable_leb_size = ubi->leb_size;
636 	vol->used_ebs = vol->reserved_pebs;
637 	vol->last_eb_bytes = vol->reserved_pebs;
638 	vol->used_bytes =
639 		(long long)vol->used_ebs * (ubi->leb_size - vol->data_pad);
640 	vol->vol_id = UBI_LAYOUT_VOLUME_ID;
641 	vol->ref_count = 1;
642 
643 	ubi_assert(!ubi->volumes[i]);
644 	ubi->volumes[vol_id2idx(ubi, vol->vol_id)] = vol;
645 	reserved_pebs += vol->reserved_pebs;
646 	ubi->vol_count += 1;
647 	vol->ubi = ubi;
648 	err = ubi_fastmap_init_checkmap(vol, UBI_LAYOUT_VOLUME_EBS);
649 	if (err)
650 		return err;
651 
652 	if (reserved_pebs > ubi->avail_pebs) {
653 		ubi_err(ubi, "not enough PEBs, required %d, available %d",
654 			reserved_pebs, ubi->avail_pebs);
655 		if (ubi->corr_peb_count)
656 			ubi_err(ubi, "%d PEBs are corrupted and not used",
657 				ubi->corr_peb_count);
658 		return -ENOSPC;
659 	}
660 	ubi->rsvd_pebs += reserved_pebs;
661 	ubi->avail_pebs -= reserved_pebs;
662 
663 	return 0;
664 }
665 
666 /**
667  * check_av - check volume attaching information.
668  * @vol: UBI volume description object
669  * @av: volume attaching information
670  *
671  * This function returns zero if the volume attaching information is consistent
672  * to the data read from the volume tabla, and %-EINVAL if not.
673  */
check_av(const struct ubi_volume * vol,const struct ubi_ainf_volume * av)674 static int check_av(const struct ubi_volume *vol,
675 		    const struct ubi_ainf_volume *av)
676 {
677 	int err;
678 
679 	if (av->highest_lnum >= vol->reserved_pebs) {
680 		err = 1;
681 		goto bad;
682 	}
683 	if (av->leb_count > vol->reserved_pebs) {
684 		err = 2;
685 		goto bad;
686 	}
687 	if (av->vol_type != vol->vol_type) {
688 		err = 3;
689 		goto bad;
690 	}
691 	if (av->used_ebs > vol->reserved_pebs) {
692 		err = 4;
693 		goto bad;
694 	}
695 	if (av->data_pad != vol->data_pad) {
696 		err = 5;
697 		goto bad;
698 	}
699 	return 0;
700 
701 bad:
702 	ubi_err(vol->ubi, "bad attaching information, error %d", err);
703 	ubi_dump_av(av);
704 	ubi_dump_vol_info(vol);
705 	return -EINVAL;
706 }
707 
708 /**
709  * check_attaching_info - check that attaching information.
710  * @ubi: UBI device description object
711  * @ai: attaching information
712  *
713  * Even though we protect on-flash data by CRC checksums, we still don't trust
714  * the media. This function ensures that attaching information is consistent to
715  * the information read from the volume table. Returns zero if the attaching
716  * information is OK and %-EINVAL if it is not.
717  */
check_attaching_info(const struct ubi_device * ubi,struct ubi_attach_info * ai)718 static int check_attaching_info(const struct ubi_device *ubi,
719 			       struct ubi_attach_info *ai)
720 {
721 	int err, i;
722 	struct ubi_ainf_volume *av;
723 	struct ubi_volume *vol;
724 
725 	if (ai->vols_found > UBI_INT_VOL_COUNT + ubi->vtbl_slots) {
726 		ubi_err(ubi, "found %d volumes while attaching, maximum is %d + %d",
727 			ai->vols_found, UBI_INT_VOL_COUNT, ubi->vtbl_slots);
728 		return -EINVAL;
729 	}
730 
731 	if (ai->highest_vol_id >= ubi->vtbl_slots + UBI_INT_VOL_COUNT &&
732 	    ai->highest_vol_id < UBI_INTERNAL_VOL_START) {
733 		ubi_err(ubi, "too large volume ID %d found",
734 			ai->highest_vol_id);
735 		return -EINVAL;
736 	}
737 
738 	for (i = 0; i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
739 		cond_resched();
740 
741 		av = ubi_find_av(ai, i);
742 		vol = ubi->volumes[i];
743 		if (!vol) {
744 			if (av)
745 				ubi_remove_av(ai, av);
746 			continue;
747 		}
748 
749 		if (vol->reserved_pebs == 0) {
750 			ubi_assert(i < ubi->vtbl_slots);
751 
752 			if (!av)
753 				continue;
754 
755 			/*
756 			 * During attaching we found a volume which does not
757 			 * exist according to the information in the volume
758 			 * table. This must have happened due to an unclean
759 			 * reboot while the volume was being removed. Discard
760 			 * these eraseblocks.
761 			 */
762 			ubi_msg(ubi, "finish volume %d removal", av->vol_id);
763 			ubi_remove_av(ai, av);
764 		} else if (av) {
765 			err = check_av(vol, av);
766 			if (err)
767 				return err;
768 		}
769 	}
770 
771 	return 0;
772 }
773 
774 /**
775  * ubi_read_volume_table - read the volume table.
776  * @ubi: UBI device description object
777  * @ai: attaching information
778  *
779  * This function reads volume table, checks it, recover from errors if needed,
780  * or creates it if needed. Returns zero in case of success and a negative
781  * error code in case of failure.
782  */
ubi_read_volume_table(struct ubi_device * ubi,struct ubi_attach_info * ai)783 int ubi_read_volume_table(struct ubi_device *ubi, struct ubi_attach_info *ai)
784 {
785 	int err;
786 	struct ubi_ainf_volume *av;
787 
788 	empty_vtbl_record.crc = cpu_to_be32(0xf116c36b);
789 
790 	/*
791 	 * The number of supported volumes is limited by the eraseblock size
792 	 * and by the UBI_MAX_VOLUMES constant.
793 	 */
794 	ubi->vtbl_slots = ubi->leb_size / UBI_VTBL_RECORD_SIZE;
795 	if (ubi->vtbl_slots > UBI_MAX_VOLUMES)
796 		ubi->vtbl_slots = UBI_MAX_VOLUMES;
797 
798 	ubi->vtbl_size = ubi->vtbl_slots * UBI_VTBL_RECORD_SIZE;
799 	ubi->vtbl_size = ALIGN(ubi->vtbl_size, ubi->min_io_size);
800 
801 	av = ubi_find_av(ai, UBI_LAYOUT_VOLUME_ID);
802 	if (!av) {
803 		/*
804 		 * No logical eraseblocks belonging to the layout volume were
805 		 * found. This could mean that the flash is just empty. In
806 		 * this case we create empty layout volume.
807 		 *
808 		 * But if flash is not empty this must be a corruption or the
809 		 * MTD device just contains garbage.
810 		 */
811 		if (ai->is_empty) {
812 			ubi->vtbl = create_empty_lvol(ubi, ai);
813 			if (IS_ERR(ubi->vtbl))
814 				return PTR_ERR(ubi->vtbl);
815 		} else {
816 			ubi_err(ubi, "the layout volume was not found");
817 			return -EINVAL;
818 		}
819 	} else {
820 		if (av->leb_count > UBI_LAYOUT_VOLUME_EBS) {
821 			/* This must not happen with proper UBI images */
822 			ubi_err(ubi, "too many LEBs (%d) in layout volume",
823 				av->leb_count);
824 			return -EINVAL;
825 		}
826 
827 		ubi->vtbl = process_lvol(ubi, ai, av);
828 		if (IS_ERR(ubi->vtbl))
829 			return PTR_ERR(ubi->vtbl);
830 	}
831 
832 	ubi->avail_pebs = ubi->good_peb_count - ubi->corr_peb_count;
833 
834 	/*
835 	 * The layout volume is OK, initialize the corresponding in-RAM data
836 	 * structures.
837 	 */
838 	err = init_volumes(ubi, ai, ubi->vtbl);
839 	if (err)
840 		goto out_free;
841 
842 	/*
843 	 * Make sure that the attaching information is consistent to the
844 	 * information stored in the volume table.
845 	 */
846 	err = check_attaching_info(ubi, ai);
847 	if (err)
848 		goto out_free;
849 
850 	return 0;
851 
852 out_free:
853 	vfree(ubi->vtbl);
854 	ubi_free_all_volumes(ubi);
855 	return err;
856 }
857 
858 /**
859  * self_vtbl_check - check volume table.
860  * @ubi: UBI device description object
861  */
self_vtbl_check(const struct ubi_device * ubi)862 static void self_vtbl_check(const struct ubi_device *ubi)
863 {
864 	if (!ubi_dbg_chk_gen(ubi))
865 		return;
866 
867 	if (vtbl_check(ubi, ubi->vtbl)) {
868 		ubi_err(ubi, "self-check failed");
869 		BUG();
870 	}
871 }
872