1	// SPDX-License-Identifier: GPL-2.0-or-later
2	/*
3	* Copyright (c) International Business Machines Corp., 2006
4	*
5	* Author: Artem Bityutskiy (Битюцкий Артём)
6	*/
7
8	/*
9	* The UBI Eraseblock Association (EBA) sub-system.
10	*
11	* This sub-system is responsible for I/O to/from logical eraseblock.
12	*
13	* Although in this implementation the EBA table is fully kept and managed in
14	* RAM, which assumes poor scalability, it might be (partially) maintained on
15	* flash in future implementations.
16	*
17	* The EBA sub-system implements per-logical eraseblock locking. Before
18	* accessing a logical eraseblock it is locked for reading or writing. The
19	* per-logical eraseblock locking is implemented by means of the lock tree. The
20	* lock tree is an RB-tree which refers all the currently locked logical
21	* eraseblocks. The lock tree elements are &struct ubi_ltree_entry objects.
22	* They are indexed by (@vol_id, @lnum) pairs.
23	*
24	* EBA also maintains the global sequence counter which is incremented each
25	* time a logical eraseblock is mapped to a physical eraseblock and it is
26	* stored in the volume identifier header. This means that each VID header has
27	* a unique sequence number. The sequence number is only increased an we assume
28	* 64 bits is enough to never overflow.
29	*/
30
31	#include <linux/slab.h>
32	#include <linux/crc32.h>
33	#include <linux/err.h>
34	#include "ubi.h"
35
36	/**
37	* struct ubi_eba_entry - structure encoding a single LEB -> PEB association
38	* @pnum: the physical eraseblock number attached to the LEB
39	*
40	* This structure is encoding a LEB -> PEB association. Note that the LEB
41	* number is not stored here, because it is the index used to access the
42	* entries table.
43	*/
44	struct ubi_eba_entry {
45	int pnum;
46	};
47
48	/**
49	* struct ubi_eba_table - LEB -> PEB association information
50	* @entries: the LEB to PEB mapping (one entry per LEB).
51	*
52	* This structure is private to the EBA logic and should be kept here.
53	* It is encoding the LEB to PEB association table, and is subject to
54	* changes.
55	*/
56	struct ubi_eba_table {
57	struct ubi_eba_entry *entries;
58	};
59
60	/**
61	* ubi_next_sqnum - get next sequence number.
62	* @ubi: UBI device description object
63	*
64	* This function returns next sequence number to use, which is just the current
65	* global sequence counter value. It also increases the global sequence
66	* counter.
67	*/
68	unsigned long long ubi_next_sqnum(struct ubi_device *ubi)
69	{
70	unsigned long long sqnum;
71
72	spin_lock(lock: &ubi->ltree_lock);
73	sqnum = ubi->global_sqnum++;
74	spin_unlock(lock: &ubi->ltree_lock);
75
76	return sqnum;
77	}
78
79	/**
80	* ubi_get_compat - get compatibility flags of a volume.
81	* @ubi: UBI device description object
82	* @vol_id: volume ID
83	*
84	* This function returns compatibility flags for an internal volume. User
85	* volumes have no compatibility flags, so %0 is returned.
86	*/
87	static int ubi_get_compat(const struct ubi_device *ubi, int vol_id)
88	{
89	if (vol_id == UBI_LAYOUT_VOLUME_ID)
90	return UBI_LAYOUT_VOLUME_COMPAT;
91	return 0;
92	}
93
94	/**
95	* ubi_eba_get_ldesc - get information about a LEB
96	* @vol: volume description object
97	* @lnum: logical eraseblock number
98	* @ldesc: the LEB descriptor to fill
99	*
100	* Used to query information about a specific LEB.
101	* It is currently only returning the physical position of the LEB, but will be
102	* extended to provide more information.
103	*/
104	void ubi_eba_get_ldesc(struct ubi_volume *vol, int lnum,
105	struct ubi_eba_leb_desc *ldesc)
106	{
107	ldesc->lnum = lnum;
108	ldesc->pnum = vol->eba_tbl->entries[lnum].pnum;
109	}
110
111	/**
112	* ubi_eba_create_table - allocate a new EBA table and initialize it with all
113	* LEBs unmapped
114	* @vol: volume containing the EBA table to copy
115	* @nentries: number of entries in the table
116	*
117	* Allocate a new EBA table and initialize it with all LEBs unmapped.
118	* Returns a valid pointer if it succeed, an ERR_PTR() otherwise.
119	*/
120	struct ubi_eba_table *ubi_eba_create_table(struct ubi_volume *vol,
121	int nentries)
122	{
123	struct ubi_eba_table *tbl;
124	int err = -ENOMEM;
125	int i;
126
127	tbl = kzalloc(size: sizeof(*tbl), GFP_KERNEL);
128	if (!tbl)
129	return ERR_PTR(error: -ENOMEM);
130
131	tbl->entries = kmalloc_array(n: nentries, size: sizeof(*tbl->entries),
132	GFP_KERNEL);
133	if (!tbl->entries)
134	goto err;
135
136	for (i = 0; i < nentries; i++)
137	tbl->entries[i].pnum = UBI_LEB_UNMAPPED;
138
139	return tbl;
140
141	err:
142	kfree(objp: tbl);
143
144	return ERR_PTR(error: err);
145	}
146
147	/**
148	* ubi_eba_destroy_table - destroy an EBA table
149	* @tbl: the table to destroy
150	*
151	* Destroy an EBA table.
152	*/
153	void ubi_eba_destroy_table(struct ubi_eba_table *tbl)
154	{
155	if (!tbl)
156	return;
157
158	kfree(objp: tbl->entries);
159	kfree(objp: tbl);
160	}
161
162	/**
163	* ubi_eba_copy_table - copy the EBA table attached to vol into another table
164	* @vol: volume containing the EBA table to copy
165	* @dst: destination
166	* @nentries: number of entries to copy
167	*
168	* Copy the EBA table stored in vol into the one pointed by dst.
169	*/
170	void ubi_eba_copy_table(struct ubi_volume *vol, struct ubi_eba_table *dst,
171	int nentries)
172	{
173	struct ubi_eba_table *src;
174	int i;
175
176	ubi_assert(dst && vol && vol->eba_tbl);
177
178	src = vol->eba_tbl;
179
180	for (i = 0; i < nentries; i++)
181	dst->entries[i].pnum = src->entries[i].pnum;
182	}
183
184	/**
185	* ubi_eba_replace_table - assign a new EBA table to a volume
186	* @vol: volume containing the EBA table to copy
187	* @tbl: new EBA table
188	*
189	* Assign a new EBA table to the volume and release the old one.
190	*/
191	void ubi_eba_replace_table(struct ubi_volume *vol, struct ubi_eba_table *tbl)
192	{
193	ubi_eba_destroy_table(tbl: vol->eba_tbl);
194	vol->eba_tbl = tbl;
195	}
196
197	/**
198	* ltree_lookup - look up the lock tree.
199	* @ubi: UBI device description object
200	* @vol_id: volume ID
201	* @lnum: logical eraseblock number
202	*
203	* This function returns a pointer to the corresponding &struct ubi_ltree_entry
204	* object if the logical eraseblock is locked and %NULL if it is not.
205	* @ubi->ltree_lock has to be locked.
206	*/
207	static struct ubi_ltree_entry *ltree_lookup(struct ubi_device *ubi, int vol_id,
208	int lnum)
209	{
210	struct rb_node *p;
211
212	p = ubi->ltree.rb_node;
213	while (p) {
214	struct ubi_ltree_entry *le;
215
216	le = rb_entry(p, struct ubi_ltree_entry, rb);
217
218	if (vol_id < le->vol_id)
219	p = p->rb_left;
220	else if (vol_id > le->vol_id)
221	p = p->rb_right;
222	else {
223	if (lnum < le->lnum)
224	p = p->rb_left;
225	else if (lnum > le->lnum)
226	p = p->rb_right;
227	else
228	return le;
229	}
230	}
231
232	return NULL;
233	}
234
235	/**
236	* ltree_add_entry - add new entry to the lock tree.
237	* @ubi: UBI device description object
238	* @vol_id: volume ID
239	* @lnum: logical eraseblock number
240	*
241	* This function adds new entry for logical eraseblock (@vol_id, @lnum) to the
242	* lock tree. If such entry is already there, its usage counter is increased.
243	* Returns pointer to the lock tree entry or %-ENOMEM if memory allocation
244	* failed.
245	*/
246	static struct ubi_ltree_entry *ltree_add_entry(struct ubi_device *ubi,
247	int vol_id, int lnum)
248	{
249	struct ubi_ltree_entry *le, *le1, *le_free;
250
251	le = kmalloc(size: sizeof(struct ubi_ltree_entry), GFP_NOFS);
252	if (!le)
253	return ERR_PTR(error: -ENOMEM);
254
255	le->users = 0;
256	init_rwsem(&le->mutex);
257	le->vol_id = vol_id;
258	le->lnum = lnum;
259
260	spin_lock(lock: &ubi->ltree_lock);
261	le1 = ltree_lookup(ubi, vol_id, lnum);
262
263	if (le1) {
264	/*
265	* This logical eraseblock is already locked. The newly
266	* allocated lock entry is not needed.
267	*/
268	le_free = le;
269	le = le1;
270	} else {
271	struct rb_node **p, *parent = NULL;
272
273	/*
274	* No lock entry, add the newly allocated one to the
275	* @ubi->ltree RB-tree.
276	*/
277	le_free = NULL;
278
279	p = &ubi->ltree.rb_node;
280	while (*p) {
281	parent = *p;
282	le1 = rb_entry(parent, struct ubi_ltree_entry, rb);
283
284	if (vol_id < le1->vol_id)
285	p = &(*p)->rb_left;
286	else if (vol_id > le1->vol_id)
287	p = &(*p)->rb_right;
288	else {
289	ubi_assert(lnum != le1->lnum);
290	if (lnum < le1->lnum)
291	p = &(*p)->rb_left;
292	else
293	p = &(*p)->rb_right;
294	}
295	}
296
297	rb_link_node(node: &le->rb, parent, rb_link: p);
298	rb_insert_color(&le->rb, &ubi->ltree);
299	}
300	le->users += 1;
301	spin_unlock(lock: &ubi->ltree_lock);
302
303	kfree(objp: le_free);
304	return le;
305	}
306
307	/**
308	* leb_read_lock - lock logical eraseblock for reading.
309	* @ubi: UBI device description object
310	* @vol_id: volume ID
311	* @lnum: logical eraseblock number
312	*
313	* This function locks a logical eraseblock for reading. Returns zero in case
314	* of success and a negative error code in case of failure.
315	*/
316	static int leb_read_lock(struct ubi_device *ubi, int vol_id, int lnum)
317	{
318	struct ubi_ltree_entry *le;
319
320	le = ltree_add_entry(ubi, vol_id, lnum);
321	if (IS_ERR(ptr: le))
322	return PTR_ERR(ptr: le);
323	down_read(sem: &le->mutex);
324	return 0;
325	}
326
327	/**
328	* leb_read_unlock - unlock logical eraseblock.
329	* @ubi: UBI device description object
330	* @vol_id: volume ID
331	* @lnum: logical eraseblock number
332	*/
333	static void leb_read_unlock(struct ubi_device *ubi, int vol_id, int lnum)
334	{
335	struct ubi_ltree_entry *le;
336
337	spin_lock(lock: &ubi->ltree_lock);
338	le = ltree_lookup(ubi, vol_id, lnum);
339	le->users -= 1;
340	ubi_assert(le->users >= 0);
341	up_read(sem: &le->mutex);
342	if (le->users == 0) {
343	rb_erase(&le->rb, &ubi->ltree);
344	kfree(objp: le);
345	}
346	spin_unlock(lock: &ubi->ltree_lock);
347	}
348
349	/**
350	* leb_write_lock - lock logical eraseblock for writing.
351	* @ubi: UBI device description object
352	* @vol_id: volume ID
353	* @lnum: logical eraseblock number
354	*
355	* This function locks a logical eraseblock for writing. Returns zero in case
356	* of success and a negative error code in case of failure.
357	*/
358	static int leb_write_lock(struct ubi_device *ubi, int vol_id, int lnum)
359	{
360	struct ubi_ltree_entry *le;
361
362	le = ltree_add_entry(ubi, vol_id, lnum);
363	if (IS_ERR(ptr: le))
364	return PTR_ERR(ptr: le);
365	down_write(sem: &le->mutex);
366	return 0;
367	}
368
369	/**
370	* leb_write_trylock - try to lock logical eraseblock for writing.
371	* @ubi: UBI device description object
372	* @vol_id: volume ID
373	* @lnum: logical eraseblock number
374	*
375	* This function locks a logical eraseblock for writing if there is no
376	* contention and does nothing if there is contention. Returns %0 in case of
377	* success, %1 in case of contention, and a negative error code in case of
378	* failure.
379	*/
380	static int leb_write_trylock(struct ubi_device *ubi, int vol_id, int lnum)
381	{
382	struct ubi_ltree_entry *le;
383
384	le = ltree_add_entry(ubi, vol_id, lnum);
385	if (IS_ERR(ptr: le))
386	return PTR_ERR(ptr: le);
387	if (down_write_trylock(sem: &le->mutex))
388	return 0;
389
390	/* Contention, cancel */
391	spin_lock(lock: &ubi->ltree_lock);
392	le->users -= 1;
393	ubi_assert(le->users >= 0);
394	if (le->users == 0) {
395	rb_erase(&le->rb, &ubi->ltree);
396	kfree(objp: le);
397	}
398	spin_unlock(lock: &ubi->ltree_lock);
399
400	return 1;
401	}
402
403	/**
404	* leb_write_unlock - unlock logical eraseblock.
405	* @ubi: UBI device description object
406	* @vol_id: volume ID
407	* @lnum: logical eraseblock number
408	*/
409	static void leb_write_unlock(struct ubi_device *ubi, int vol_id, int lnum)
410	{
411	struct ubi_ltree_entry *le;
412
413	spin_lock(lock: &ubi->ltree_lock);
414	le = ltree_lookup(ubi, vol_id, lnum);
415	le->users -= 1;
416	ubi_assert(le->users >= 0);
417	up_write(sem: &le->mutex);
418	if (le->users == 0) {
419	rb_erase(&le->rb, &ubi->ltree);
420	kfree(objp: le);
421	}
422	spin_unlock(lock: &ubi->ltree_lock);
423	}
424
425	/**
426	* ubi_eba_is_mapped - check if a LEB is mapped.
427	* @vol: volume description object
428	* @lnum: logical eraseblock number
429	*
430	* This function returns true if the LEB is mapped, false otherwise.
431	*/
432	bool ubi_eba_is_mapped(struct ubi_volume *vol, int lnum)
433	{
434	return vol->eba_tbl->entries[lnum].pnum >= 0;
435	}
436
437	/**
438	* ubi_eba_unmap_leb - un-map logical eraseblock.
439	* @ubi: UBI device description object
440	* @vol: volume description object
441	* @lnum: logical eraseblock number
442	*
443	* This function un-maps logical eraseblock @lnum and schedules corresponding
444	* physical eraseblock for erasure. Returns zero in case of success and a
445	* negative error code in case of failure.
446	*/
447	int ubi_eba_unmap_leb(struct ubi_device *ubi, struct ubi_volume *vol,
448	int lnum)
449	{
450	int err, pnum, vol_id = vol->vol_id;
451
452	if (ubi->ro_mode)
453	return -EROFS;
454
455	err = leb_write_lock(ubi, vol_id, lnum);
456	if (err)
457	return err;
458
459	pnum = vol->eba_tbl->entries[lnum].pnum;
460	if (pnum < 0)
461	/* This logical eraseblock is already unmapped */
462	goto out_unlock;
463
464	dbg_eba("erase LEB %d:%d, PEB %d", vol_id, lnum, pnum);
465
466	down_read(sem: &ubi->fm_eba_sem);
467	vol->eba_tbl->entries[lnum].pnum = UBI_LEB_UNMAPPED;
468	up_read(sem: &ubi->fm_eba_sem);
469	err = ubi_wl_put_peb(ubi, vol_id, lnum, pnum, torture: 0);
470
471	out_unlock:
472	leb_write_unlock(ubi, vol_id, lnum);
473	return err;
474	}
475
476	#ifdef CONFIG_MTD_UBI_FASTMAP
477	/**
478	* check_mapping - check and fixup a mapping
479	* @ubi: UBI device description object
480	* @vol: volume description object
481	* @lnum: logical eraseblock number
482	* @pnum: physical eraseblock number
483	*
484	* Checks whether a given mapping is valid. Fastmap cannot track LEB unmap
485	* operations, if such an operation is interrupted the mapping still looks
486	* good, but upon first read an ECC is reported to the upper layer.
487	* Normaly during the full-scan at attach time this is fixed, for Fastmap
488	* we have to deal with it while reading.
489	* If the PEB behind a LEB shows this symthom we change the mapping to
490	* %UBI_LEB_UNMAPPED and schedule the PEB for erasure.
491	*
492	* Returns 0 on success, negative error code in case of failure.
493	*/
494	static int check_mapping(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
495	int *pnum)
496	{
497	int err;
498	struct ubi_vid_io_buf *vidb;
499	struct ubi_vid_hdr *vid_hdr;
500
501	if (!ubi->fast_attach)
502	return 0;
503
504	if (!vol->checkmap || test_bit(lnum, vol->checkmap))
505	return 0;
506
507	vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS);
508	if (!vidb)
509	return -ENOMEM;
510
511	err = ubi_io_read_vid_hdr(ubi, pnum: *pnum, vidb, verbose: 0);
512	if (err > 0 && err != UBI_IO_BITFLIPS) {
513	int torture = 0;
514
515	switch (err) {
516	case UBI_IO_FF:
517	case UBI_IO_FF_BITFLIPS:
518	case UBI_IO_BAD_HDR:
519	case UBI_IO_BAD_HDR_EBADMSG:
520	break;
521	default:
522	ubi_assert(0);
523	}
524
525	if (err == UBI_IO_BAD_HDR_EBADMSG || err == UBI_IO_FF_BITFLIPS)
526	torture = 1;
527
528	down_read(sem: &ubi->fm_eba_sem);
529	vol->eba_tbl->entries[lnum].pnum = UBI_LEB_UNMAPPED;
530	up_read(sem: &ubi->fm_eba_sem);
531	ubi_wl_put_peb(ubi, vol_id: vol->vol_id, lnum, pnum: *pnum, torture);
532
533	*pnum = UBI_LEB_UNMAPPED;
534	} else if (err < 0) {
535	ubi_err(ubi, fmt: "unable to read VID header back from PEB %i: %i",
536	*pnum, err);
537
538	goto out_free;
539	} else {
540	int found_vol_id, found_lnum;
541
542	ubi_assert(err == 0 || err == UBI_IO_BITFLIPS);
543
544	vid_hdr = ubi_get_vid_hdr(vidb);
545	found_vol_id = be32_to_cpu(vid_hdr->vol_id);
546	found_lnum = be32_to_cpu(vid_hdr->lnum);
547
548	if (found_lnum != lnum || found_vol_id != vol->vol_id) {
549	ubi_err(ubi, fmt: "EBA mismatch! PEB %i is LEB %i:%i instead of LEB %i:%i",
550	*pnum, found_vol_id, found_lnum, vol->vol_id, lnum);
551	ubi_ro_mode(ubi);
552	err = -EINVAL;
553	goto out_free;
554	}
555	}
556
557	set_bit(nr: lnum, addr: vol->checkmap);
558	err = 0;
559
560	out_free:
561	ubi_free_vid_buf(vidb);
562
563	return err;
564	}
565	#else
566	static int check_mapping(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
567	int *pnum)
568	{
569	return 0;
570	}
571	#endif
572
573	/**
574	* ubi_eba_read_leb - read data.
575	* @ubi: UBI device description object
576	* @vol: volume description object
577	* @lnum: logical eraseblock number
578	* @buf: buffer to store the read data
579	* @offset: offset from where to read
580	* @len: how many bytes to read
581	* @check: data CRC check flag
582	*
583	* If the logical eraseblock @lnum is unmapped, @buf is filled with 0xFF
584	* bytes. The @check flag only makes sense for static volumes and forces
585	* eraseblock data CRC checking.
586	*
587	* In case of success this function returns zero. In case of a static volume,
588	* if data CRC mismatches - %-EBADMSG is returned. %-EBADMSG may also be
589	* returned for any volume type if an ECC error was detected by the MTD device
590	* driver. Other negative error cored may be returned in case of other errors.
591	*/
592	int ubi_eba_read_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
593	void *buf, int offset, int len, int check)
594	{
595	int err, pnum, scrub = 0, vol_id = vol->vol_id;
596	struct ubi_vid_io_buf *vidb;
597	struct ubi_vid_hdr *vid_hdr;
598	uint32_t crc;
599
600	err = leb_read_lock(ubi, vol_id, lnum);
601	if (err)
602	return err;
603
604	pnum = vol->eba_tbl->entries[lnum].pnum;
605	if (pnum >= 0) {
606	err = check_mapping(ubi, vol, lnum, pnum: &pnum);
607	if (err < 0)
608	goto out_unlock;
609	}
610
611	if (pnum == UBI_LEB_UNMAPPED) {
612	/*
613	* The logical eraseblock is not mapped, fill the whole buffer
614	* with 0xFF bytes. The exception is static volumes for which
615	* it is an error to read unmapped logical eraseblocks.
616	*/
617	dbg_eba("read %d bytes from offset %d of LEB %d:%d (unmapped)",
618	len, offset, vol_id, lnum);
619	leb_read_unlock(ubi, vol_id, lnum);
620	ubi_assert(vol->vol_type != UBI_STATIC_VOLUME);
621	memset(buf, 0xFF, len);
622	return 0;
623	}
624
625	dbg_eba("read %d bytes from offset %d of LEB %d:%d, PEB %d",
626	len, offset, vol_id, lnum, pnum);
627
628	if (vol->vol_type == UBI_DYNAMIC_VOLUME)
629	check = 0;
630
631	retry:
632	if (check) {
633	vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS);
634	if (!vidb) {
635	err = -ENOMEM;
636	goto out_unlock;
637	}
638
639	vid_hdr = ubi_get_vid_hdr(vidb);
640
641	err = ubi_io_read_vid_hdr(ubi, pnum, vidb, verbose: 1);
642	if (err && err != UBI_IO_BITFLIPS) {
643	if (err > 0) {
644	/*
645	* The header is either absent or corrupted.
646	* The former case means there is a bug -
647	* switch to read-only mode just in case.
648	* The latter case means a real corruption - we
649	* may try to recover data. FIXME: but this is
650	* not implemented.
651	*/
652	if (err == UBI_IO_BAD_HDR_EBADMSG ||
653	err == UBI_IO_BAD_HDR) {
654	ubi_warn(ubi, fmt: "corrupted VID header at PEB %d, LEB %d:%d",
655	pnum, vol_id, lnum);
656	err = -EBADMSG;
657	} else {
658	/*
659	* Ending up here in the non-Fastmap case
660	* is a clear bug as the VID header had to
661	* be present at scan time to have it referenced.
662	* With fastmap the story is more complicated.
663	* Fastmap has the mapping info without the need
664	* of a full scan. So the LEB could have been
665	* unmapped, Fastmap cannot know this and keeps
666	* the LEB referenced.
667	* This is valid and works as the layer above UBI
668	* has to do bookkeeping about used/referenced
669	* LEBs in any case.
670	*/
671	if (ubi->fast_attach) {
672	err = -EBADMSG;
673	} else {
674	err = -EINVAL;
675	ubi_ro_mode(ubi);
676	}
677	}
678	}
679	goto out_free;
680	} else if (err == UBI_IO_BITFLIPS)
681	scrub = 1;
682
683	ubi_assert(lnum < be32_to_cpu(vid_hdr->used_ebs));
684	ubi_assert(len == be32_to_cpu(vid_hdr->data_size));
685
686	crc = be32_to_cpu(vid_hdr->data_crc);
687	ubi_free_vid_buf(vidb);
688	}
689
690	err = ubi_io_read_data(ubi, buf, pnum, offset, len);
691	if (err) {
692	if (err == UBI_IO_BITFLIPS)
693	scrub = 1;
694	else if (mtd_is_eccerr(err)) {
695	if (vol->vol_type == UBI_DYNAMIC_VOLUME)
696	goto out_unlock;
697	scrub = 1;
698	if (!check) {
699	ubi_msg(ubi, fmt: "force data checking");
700	check = 1;
701	goto retry;
702	}
703	} else
704	goto out_unlock;
705	}
706
707	if (check) {
708	uint32_t crc1 = crc32(UBI_CRC32_INIT, buf, len);
709	if (crc1 != crc) {
710	ubi_warn(ubi, fmt: "CRC error: calculated %#08x, must be %#08x",
711	crc1, crc);
712	err = -EBADMSG;
713	goto out_unlock;
714	}
715	}
716
717	if (scrub)
718	err = ubi_wl_scrub_peb(ubi, pnum);
719
720	leb_read_unlock(ubi, vol_id, lnum);
721	return err;
722
723	out_free:
724	ubi_free_vid_buf(vidb);
725	out_unlock:
726	leb_read_unlock(ubi, vol_id, lnum);
727	return err;
728	}
729
730	/**
731	* ubi_eba_read_leb_sg - read data into a scatter gather list.
732	* @ubi: UBI device description object
733	* @vol: volume description object
734	* @lnum: logical eraseblock number
735	* @sgl: UBI scatter gather list to store the read data
736	* @offset: offset from where to read
737	* @len: how many bytes to read
738	* @check: data CRC check flag
739	*
740	* This function works exactly like ubi_eba_read_leb(). But instead of
741	* storing the read data into a buffer it writes to an UBI scatter gather
742	* list.
743	*/
744	int ubi_eba_read_leb_sg(struct ubi_device *ubi, struct ubi_volume *vol,
745	struct ubi_sgl *sgl, int lnum, int offset, int len,
746	int check)
747	{
748	int to_read;
749	int ret;
750	struct scatterlist *sg;
751
752	for (;;) {
753	ubi_assert(sgl->list_pos < UBI_MAX_SG_COUNT);
754	sg = &sgl->sg[sgl->list_pos];
755	if (len < sg->length - sgl->page_pos)
756	to_read = len;
757	else
758	to_read = sg->length - sgl->page_pos;
759
760	ret = ubi_eba_read_leb(ubi, vol, lnum,
761	buf: sg_virt(sg) + sgl->page_pos, offset,
762	len: to_read, check);
763	if (ret < 0)
764	return ret;
765
766	offset += to_read;
767	len -= to_read;
768	if (!len) {
769	sgl->page_pos += to_read;
770	if (sgl->page_pos == sg->length) {
771	sgl->list_pos++;
772	sgl->page_pos = 0;
773	}
774
775	break;
776	}
777
778	sgl->list_pos++;
779	sgl->page_pos = 0;
780	}
781
782	return ret;
783	}
784
785	/**
786	* try_recover_peb - try to recover from write failure.
787	* @vol: volume description object
788	* @pnum: the physical eraseblock to recover
789	* @lnum: logical eraseblock number
790	* @buf: data which was not written because of the write failure
791	* @offset: offset of the failed write
792	* @len: how many bytes should have been written
793	* @vidb: VID buffer
794	* @retry: whether the caller should retry in case of failure
795	*
796	* This function is called in case of a write failure and moves all good data
797	* from the potentially bad physical eraseblock to a good physical eraseblock.
798	* This function also writes the data which was not written due to the failure.
799	* Returns 0 in case of success, and a negative error code in case of failure.
800	* In case of failure, the %retry parameter is set to false if this is a fatal
801	* error (retrying won't help), and true otherwise.
802	*/
803	static int try_recover_peb(struct ubi_volume *vol, int pnum, int lnum,
804	const void *buf, int offset, int len,
805	struct ubi_vid_io_buf *vidb, bool *retry)
806	{
807	struct ubi_device *ubi = vol->ubi;
808	struct ubi_vid_hdr *vid_hdr;
809	int new_pnum, err, vol_id = vol->vol_id, data_size;
810	uint32_t crc;
811
812	*retry = false;
813
814	new_pnum = ubi_wl_get_peb(ubi);
815	if (new_pnum < 0) {
816	err = new_pnum;
817	goto out_put;
818	}
819
820	ubi_msg(ubi, fmt: "recover PEB %d, move data to PEB %d",
821	pnum, new_pnum);
822
823	err = ubi_io_read_vid_hdr(ubi, pnum, vidb, verbose: 1);
824	if (err && err != UBI_IO_BITFLIPS) {
825	if (err > 0)
826	err = -EIO;
827	goto out_put;
828	}
829
830	vid_hdr = ubi_get_vid_hdr(vidb);
831	ubi_assert(vid_hdr->vol_type == UBI_VID_DYNAMIC);
832
833	mutex_lock(&ubi->buf_mutex);
834	memset(ubi->peb_buf + offset, 0xFF, len);
835
836	/* Read everything before the area where the write failure happened */
837	if (offset > 0) {
838	err = ubi_io_read_data(ubi, buf: ubi->peb_buf, pnum, offset: 0, len: offset);
839	if (err && err != UBI_IO_BITFLIPS)
840	goto out_unlock;
841	}
842
843	*retry = true;
844
845	memcpy(ubi->peb_buf + offset, buf, len);
846
847	data_size = offset + len;
848	crc = crc32(UBI_CRC32_INIT, ubi->peb_buf, data_size);
849	vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
850	vid_hdr->copy_flag = 1;
851	vid_hdr->data_size = cpu_to_be32(data_size);
852	vid_hdr->data_crc = cpu_to_be32(crc);
853	err = ubi_io_write_vid_hdr(ubi, pnum: new_pnum, vidb);
854	if (err)
855	goto out_unlock;
856
857	err = ubi_io_write_data(ubi, buf: ubi->peb_buf, pnum: new_pnum, offset: 0, len: data_size);
858
859	out_unlock:
860	mutex_unlock(lock: &ubi->buf_mutex);
861
862	if (!err)
863	vol->eba_tbl->entries[lnum].pnum = new_pnum;
864
865	out_put:
866	up_read(sem: &ubi->fm_eba_sem);
867
868	if (!err) {
869	ubi_wl_put_peb(ubi, vol_id, lnum, pnum, torture: 1);
870	ubi_msg(ubi, fmt: "data was successfully recovered");
871	} else if (new_pnum >= 0) {
872	/*
873	* Bad luck? This physical eraseblock is bad too? Crud. Let's
874	* try to get another one.
875	*/
876	ubi_wl_put_peb(ubi, vol_id, lnum, pnum: new_pnum, torture: 1);
877	ubi_warn(ubi, fmt: "failed to write to PEB %d", new_pnum);
878	}
879
880	return err;
881	}
882
883	/**
884	* recover_peb - recover from write failure.
885	* @ubi: UBI device description object
886	* @pnum: the physical eraseblock to recover
887	* @vol_id: volume ID
888	* @lnum: logical eraseblock number
889	* @buf: data which was not written because of the write failure
890	* @offset: offset of the failed write
891	* @len: how many bytes should have been written
892	*
893	* This function is called in case of a write failure and moves all good data
894	* from the potentially bad physical eraseblock to a good physical eraseblock.
895	* This function also writes the data which was not written due to the failure.
896	* Returns 0 in case of success, and a negative error code in case of failure.
897	* This function tries %UBI_IO_RETRIES before giving up.
898	*/
899	static int recover_peb(struct ubi_device *ubi, int pnum, int vol_id, int lnum,
900	const void *buf, int offset, int len)
901	{
902	int err, idx = vol_id2idx(ubi, vol_id), tries;
903	struct ubi_volume *vol = ubi->volumes[idx];
904	struct ubi_vid_io_buf *vidb;
905
906	vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS);
907	if (!vidb)
908	return -ENOMEM;
909
910	for (tries = 0; tries <= UBI_IO_RETRIES; tries++) {
911	bool retry;
912
913	err = try_recover_peb(vol, pnum, lnum, buf, offset, len, vidb,
914	retry: &retry);
915	if (!err || !retry)
916	break;
917
918	ubi_msg(ubi, fmt: "try again");
919	}
920
921	ubi_free_vid_buf(vidb);
922
923	return err;
924	}
925
926	/**
927	* try_write_vid_and_data - try to write VID header and data to a new PEB.
928	* @vol: volume description object
929	* @lnum: logical eraseblock number
930	* @vidb: the VID buffer to write
931	* @buf: buffer containing the data
932	* @offset: where to start writing data
933	* @len: how many bytes should be written
934	*
935	* This function tries to write VID header and data belonging to logical
936	* eraseblock @lnum of volume @vol to a new physical eraseblock. Returns zero
937	* in case of success and a negative error code in case of failure.
938	* In case of error, it is possible that something was still written to the
939	* flash media, but may be some garbage.
940	*/
941	static int try_write_vid_and_data(struct ubi_volume *vol, int lnum,
942	struct ubi_vid_io_buf *vidb, const void *buf,
943	int offset, int len)
944	{
945	struct ubi_device *ubi = vol->ubi;
946	int pnum, opnum, err, err2, vol_id = vol->vol_id;
947
948	pnum = ubi_wl_get_peb(ubi);
949	if (pnum < 0) {
950	err = pnum;
951	goto out_put;
952	}
953
954	opnum = vol->eba_tbl->entries[lnum].pnum;
955
956	dbg_eba("write VID hdr and %d bytes at offset %d of LEB %d:%d, PEB %d",
957	len, offset, vol_id, lnum, pnum);
958
959	err = ubi_io_write_vid_hdr(ubi, pnum, vidb);
960	if (err) {
961	ubi_warn(ubi, fmt: "failed to write VID header to LEB %d:%d, PEB %d",
962	vol_id, lnum, pnum);
963	goto out_put;
964	}
965
966	if (len) {
967	err = ubi_io_write_data(ubi, buf, pnum, offset, len);
968	if (err) {
969	ubi_warn(ubi,
970	fmt: "failed to write %d bytes at offset %d of LEB %d:%d, PEB %d",
971	len, offset, vol_id, lnum, pnum);
972	goto out_put;
973	}
974	}
975
976	vol->eba_tbl->entries[lnum].pnum = pnum;
977
978	out_put:
979	up_read(sem: &ubi->fm_eba_sem);
980
981	if (err && pnum >= 0) {
982	err2 = ubi_wl_put_peb(ubi, vol_id, lnum, pnum, torture: 1);
983	if (err2) {
984	ubi_warn(ubi, fmt: "failed to return physical eraseblock %d, error %d",
985	pnum, err2);
986	}
987	} else if (!err && opnum >= 0) {
988	err2 = ubi_wl_put_peb(ubi, vol_id, lnum, pnum: opnum, torture: 0);
989	if (err2) {
990	ubi_warn(ubi, fmt: "failed to return physical eraseblock %d, error %d",
991	opnum, err2);
992	}
993	}
994
995	return err;
996	}
997
998	/**
999	* ubi_eba_write_leb - write data to dynamic volume.
1000	* @ubi: UBI device description object
1001	* @vol: volume description object
1002	* @lnum: logical eraseblock number
1003	* @buf: the data to write
1004	* @offset: offset within the logical eraseblock where to write
1005	* @len: how many bytes to write
1006	*
1007	* This function writes data to logical eraseblock @lnum of a dynamic volume
1008	* @vol. Returns zero in case of success and a negative error code in case
1009	* of failure. In case of error, it is possible that something was still
1010	* written to the flash media, but may be some garbage.
1011	* This function retries %UBI_IO_RETRIES times before giving up.
1012	*/
1013	int ubi_eba_write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
1014	const void *buf, int offset, int len)
1015	{
1016	int err, pnum, tries, vol_id = vol->vol_id;
1017	struct ubi_vid_io_buf *vidb;
1018	struct ubi_vid_hdr *vid_hdr;
1019
1020	if (ubi->ro_mode)
1021	return -EROFS;
1022
1023	err = leb_write_lock(ubi, vol_id, lnum);
1024	if (err)
1025	return err;
1026
1027	pnum = vol->eba_tbl->entries[lnum].pnum;
1028	if (pnum >= 0) {
1029	err = check_mapping(ubi, vol, lnum, pnum: &pnum);
1030	if (err < 0)
1031	goto out;
1032	}
1033
1034	if (pnum >= 0) {
1035	dbg_eba("write %d bytes at offset %d of LEB %d:%d, PEB %d",
1036	len, offset, vol_id, lnum, pnum);
1037
1038	err = ubi_io_write_data(ubi, buf, pnum, offset, len);
1039	if (err) {
1040	ubi_warn(ubi, fmt: "failed to write data to PEB %d", pnum);
1041	if (err == -EIO && ubi->bad_allowed)
1042	err = recover_peb(ubi, pnum, vol_id, lnum, buf,
1043	offset, len);
1044	}
1045
1046	goto out;
1047	}
1048
1049	/*
1050	* The logical eraseblock is not mapped. We have to get a free physical
1051	* eraseblock and write the volume identifier header there first.
1052	*/
1053	vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS);
1054	if (!vidb) {
1055	leb_write_unlock(ubi, vol_id, lnum);
1056	return -ENOMEM;
1057	}
1058
1059	vid_hdr = ubi_get_vid_hdr(vidb);
1060
1061	vid_hdr->vol_type = UBI_VID_DYNAMIC;
1062	vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
1063	vid_hdr->vol_id = cpu_to_be32(vol_id);
1064	vid_hdr->lnum = cpu_to_be32(lnum);
1065	vid_hdr->compat = ubi_get_compat(ubi, vol_id);
1066	vid_hdr->data_pad = cpu_to_be32(vol->data_pad);
1067
1068	for (tries = 0; tries <= UBI_IO_RETRIES; tries++) {
1069	err = try_write_vid_and_data(vol, lnum, vidb, buf, offset, len);
1070	if (err != -EIO || !ubi->bad_allowed)
1071	break;
1072
1073	/*
1074	* Fortunately, this is the first write operation to this
1075	* physical eraseblock, so just put it and request a new one.
1076	* We assume that if this physical eraseblock went bad, the
1077	* erase code will handle that.
1078	*/
1079	vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
1080	ubi_msg(ubi, fmt: "try another PEB");
1081	}
1082
1083	ubi_free_vid_buf(vidb);
1084
1085	out:
1086	if (err)
1087	ubi_ro_mode(ubi);
1088
1089	leb_write_unlock(ubi, vol_id, lnum);
1090
1091	return err;
1092	}
1093
1094	/**
1095	* ubi_eba_write_leb_st - write data to static volume.
1096	* @ubi: UBI device description object
1097	* @vol: volume description object
1098	* @lnum: logical eraseblock number
1099	* @buf: data to write
1100	* @len: how many bytes to write
1101	* @used_ebs: how many logical eraseblocks will this volume contain
1102	*
1103	* This function writes data to logical eraseblock @lnum of static volume
1104	* @vol. The @used_ebs argument should contain total number of logical
1105	* eraseblock in this static volume.
1106	*
1107	* When writing to the last logical eraseblock, the @len argument doesn't have
1108	* to be aligned to the minimal I/O unit size. Instead, it has to be equivalent
1109	* to the real data size, although the @buf buffer has to contain the
1110	* alignment. In all other cases, @len has to be aligned.
1111	*
1112	* It is prohibited to write more than once to logical eraseblocks of static
1113	* volumes. This function returns zero in case of success and a negative error
1114	* code in case of failure.
1115	*/
1116	int ubi_eba_write_leb_st(struct ubi_device *ubi, struct ubi_volume *vol,
1117	int lnum, const void *buf, int len, int used_ebs)
1118	{
1119	int err, tries, data_size = len, vol_id = vol->vol_id;
1120	struct ubi_vid_io_buf *vidb;
1121	struct ubi_vid_hdr *vid_hdr;
1122	uint32_t crc;
1123
1124	if (ubi->ro_mode)
1125	return -EROFS;
1126
1127	if (lnum == used_ebs - 1)
1128	/* If this is the last LEB @len may be unaligned */
1129	len = ALIGN(data_size, ubi->min_io_size);
1130	else
1131	ubi_assert(!(len & (ubi->min_io_size - 1)));
1132
1133	vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS);
1134	if (!vidb)
1135	return -ENOMEM;
1136
1137	vid_hdr = ubi_get_vid_hdr(vidb);
1138
1139	err = leb_write_lock(ubi, vol_id, lnum);
1140	if (err)
1141	goto out;
1142
1143	vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
1144	vid_hdr->vol_id = cpu_to_be32(vol_id);
1145	vid_hdr->lnum = cpu_to_be32(lnum);
1146	vid_hdr->compat = ubi_get_compat(ubi, vol_id);
1147	vid_hdr->data_pad = cpu_to_be32(vol->data_pad);
1148
1149	crc = crc32(UBI_CRC32_INIT, buf, data_size);
1150	vid_hdr->vol_type = UBI_VID_STATIC;
1151	vid_hdr->data_size = cpu_to_be32(data_size);
1152	vid_hdr->used_ebs = cpu_to_be32(used_ebs);
1153	vid_hdr->data_crc = cpu_to_be32(crc);
1154
1155	ubi_assert(vol->eba_tbl->entries[lnum].pnum < 0);
1156
1157	for (tries = 0; tries <= UBI_IO_RETRIES; tries++) {
1158	err = try_write_vid_and_data(vol, lnum, vidb, buf, offset: 0, len);
1159	if (err != -EIO || !ubi->bad_allowed)
1160	break;
1161
1162	vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
1163	ubi_msg(ubi, fmt: "try another PEB");
1164	}
1165
1166	if (err)
1167	ubi_ro_mode(ubi);
1168
1169	leb_write_unlock(ubi, vol_id, lnum);
1170
1171	out:
1172	ubi_free_vid_buf(vidb);
1173
1174	return err;
1175	}
1176
1177	/*
1178	* ubi_eba_atomic_leb_change - change logical eraseblock atomically.
1179	* @ubi: UBI device description object
1180	* @vol: volume description object
1181	* @lnum: logical eraseblock number
1182	* @buf: data to write
1183	* @len: how many bytes to write
1184	*
1185	* This function changes the contents of a logical eraseblock atomically. @buf
1186	* has to contain new logical eraseblock data, and @len - the length of the
1187	* data, which has to be aligned. This function guarantees that in case of an
1188	* unclean reboot the old contents is preserved. Returns zero in case of
1189	* success and a negative error code in case of failure.
1190	*
1191	* UBI reserves one LEB for the "atomic LEB change" operation, so only one
1192	* LEB change may be done at a time. This is ensured by @ubi->alc_mutex.
1193	*/
1194	int ubi_eba_atomic_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
1195	int lnum, const void *buf, int len)
1196	{
1197	int err, tries, vol_id = vol->vol_id;
1198	struct ubi_vid_io_buf *vidb;
1199	struct ubi_vid_hdr *vid_hdr;
1200	uint32_t crc;
1201
1202	if (ubi->ro_mode)
1203	return -EROFS;
1204
1205	if (len == 0) {
1206	/*
1207	* Special case when data length is zero. In this case the LEB
1208	* has to be unmapped and mapped somewhere else.
1209	*/
1210	err = ubi_eba_unmap_leb(ubi, vol, lnum);
1211	if (err)
1212	return err;
1213	return ubi_eba_write_leb(ubi, vol, lnum, NULL, offset: 0, len: 0);
1214	}
1215
1216	vidb = ubi_alloc_vid_buf(ubi, GFP_NOFS);
1217	if (!vidb)
1218	return -ENOMEM;
1219
1220	vid_hdr = ubi_get_vid_hdr(vidb);
1221
1222	mutex_lock(&ubi->alc_mutex);
1223	err = leb_write_lock(ubi, vol_id, lnum);
1224	if (err)
1225	goto out_mutex;
1226
1227	vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
1228	vid_hdr->vol_id = cpu_to_be32(vol_id);
1229	vid_hdr->lnum = cpu_to_be32(lnum);
1230	vid_hdr->compat = ubi_get_compat(ubi, vol_id);
1231	vid_hdr->data_pad = cpu_to_be32(vol->data_pad);
1232
1233	crc = crc32(UBI_CRC32_INIT, buf, len);
1234	vid_hdr->vol_type = UBI_VID_DYNAMIC;
1235	vid_hdr->data_size = cpu_to_be32(len);
1236	vid_hdr->copy_flag = 1;
1237	vid_hdr->data_crc = cpu_to_be32(crc);
1238
1239	dbg_eba("change LEB %d:%d", vol_id, lnum);
1240
1241	for (tries = 0; tries <= UBI_IO_RETRIES; tries++) {
1242	err = try_write_vid_and_data(vol, lnum, vidb, buf, offset: 0, len);
1243	if (err != -EIO || !ubi->bad_allowed)
1244	break;
1245
1246	vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
1247	ubi_msg(ubi, fmt: "try another PEB");
1248	}
1249
1250	/*
1251	* This flash device does not admit of bad eraseblocks or
1252	* something nasty and unexpected happened. Switch to read-only
1253	* mode just in case.
1254	*/
1255	if (err)
1256	ubi_ro_mode(ubi);
1257
1258	leb_write_unlock(ubi, vol_id, lnum);
1259
1260	out_mutex:
1261	mutex_unlock(lock: &ubi->alc_mutex);
1262	ubi_free_vid_buf(vidb);
1263	return err;
1264	}
1265
1266	/**
1267	* is_error_sane - check whether a read error is sane.
1268	* @err: code of the error happened during reading
1269	*
1270	* This is a helper function for 'ubi_eba_copy_leb()' which is called when we
1271	* cannot read data from the target PEB (an error @err happened). If the error
1272	* code is sane, then we treat this error as non-fatal. Otherwise the error is
1273	* fatal and UBI will be switched to R/O mode later.
1274	*
1275	* The idea is that we try not to switch to R/O mode if the read error is
1276	* something which suggests there was a real read problem. E.g., %-EIO. Or a
1277	* memory allocation failed (-%ENOMEM). Otherwise, it is safer to switch to R/O
1278	* mode, simply because we do not know what happened at the MTD level, and we
1279	* cannot handle this. E.g., the underlying driver may have become crazy, and
1280	* it is safer to switch to R/O mode to preserve the data.
1281	*
1282	* And bear in mind, this is about reading from the target PEB, i.e. the PEB
1283	* which we have just written.
1284	*/
1285	static int is_error_sane(int err)
1286	{
1287	if (err == -EIO || err == -ENOMEM || err == UBI_IO_BAD_HDR ||
1288	err == UBI_IO_BAD_HDR_EBADMSG || err == -ETIMEDOUT)
1289	return 0;
1290	return 1;
1291	}
1292
1293	/**
1294	* ubi_eba_copy_leb - copy logical eraseblock.
1295	* @ubi: UBI device description object
1296	* @from: physical eraseblock number from where to copy
1297	* @to: physical eraseblock number where to copy
1298	* @vidb: data structure from where the VID header is derived
1299	*
1300	* This function copies logical eraseblock from physical eraseblock @from to
1301	* physical eraseblock @to. The @vid_hdr buffer may be changed by this
1302	* function. Returns:
1303	* o %0 in case of success;
1304	* o %MOVE_CANCEL_RACE, %MOVE_TARGET_WR_ERR, %MOVE_TARGET_BITFLIPS, etc;
1305	* o a negative error code in case of failure.
1306	*/
1307	int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
1308	struct ubi_vid_io_buf *vidb)
1309	{
1310	int err, vol_id, lnum, data_size, aldata_size, idx;
1311	struct ubi_vid_hdr *vid_hdr = ubi_get_vid_hdr(vidb);
1312	struct ubi_volume *vol;
1313	uint32_t crc;
1314
1315	ubi_assert(rwsem_is_locked(&ubi->fm_eba_sem));
1316
1317	vol_id = be32_to_cpu(vid_hdr->vol_id);
1318	lnum = be32_to_cpu(vid_hdr->lnum);
1319
1320	dbg_wl("copy LEB %d:%d, PEB %d to PEB %d", vol_id, lnum, from, to);
1321
1322	if (vid_hdr->vol_type == UBI_VID_STATIC) {
1323	data_size = be32_to_cpu(vid_hdr->data_size);
1324	aldata_size = ALIGN(data_size, ubi->min_io_size);
1325	} else
1326	data_size = aldata_size =
1327	ubi->leb_size - be32_to_cpu(vid_hdr->data_pad);
1328
1329	idx = vol_id2idx(ubi, vol_id);
1330	spin_lock(lock: &ubi->volumes_lock);
1331	/*
1332	* Note, we may race with volume deletion, which means that the volume
1333	* this logical eraseblock belongs to might be being deleted. Since the
1334	* volume deletion un-maps all the volume's logical eraseblocks, it will
1335	* be locked in 'ubi_wl_put_peb()' and wait for the WL worker to finish.
1336	*/
1337	vol = ubi->volumes[idx];
1338	spin_unlock(lock: &ubi->volumes_lock);
1339	if (!vol) {
1340	/* No need to do further work, cancel */
1341	dbg_wl("volume %d is being removed, cancel", vol_id);
1342	return MOVE_CANCEL_RACE;
1343	}
1344
1345	/*
1346	* We do not want anybody to write to this logical eraseblock while we
1347	* are moving it, so lock it.
1348	*
1349	* Note, we are using non-waiting locking here, because we cannot sleep
1350	* on the LEB, since it may cause deadlocks. Indeed, imagine a task is
1351	* unmapping the LEB which is mapped to the PEB we are going to move
1352	* (@from). This task locks the LEB and goes sleep in the
1353	* 'ubi_wl_put_peb()' function on the @ubi->move_mutex. In turn, we are
1354	* holding @ubi->move_mutex and go sleep on the LEB lock. So, if the
1355	* LEB is already locked, we just do not move it and return
1356	* %MOVE_RETRY. Note, we do not return %MOVE_CANCEL_RACE here because
1357	* we do not know the reasons of the contention - it may be just a
1358	* normal I/O on this LEB, so we want to re-try.
1359	*/
1360	err = leb_write_trylock(ubi, vol_id, lnum);
1361	if (err) {
1362	dbg_wl("contention on LEB %d:%d, cancel", vol_id, lnum);
1363	return MOVE_RETRY;
1364	}
1365
1366	/*
1367	* The LEB might have been put meanwhile, and the task which put it is
1368	* probably waiting on @ubi->move_mutex. No need to continue the work,
1369	* cancel it.
1370	*/
1371	if (vol->eba_tbl->entries[lnum].pnum != from) {
1372	dbg_wl("LEB %d:%d is no longer mapped to PEB %d, mapped to PEB %d, cancel",
1373	vol_id, lnum, from, vol->eba_tbl->entries[lnum].pnum);
1374	err = MOVE_CANCEL_RACE;
1375	goto out_unlock_leb;
1376	}
1377
1378	/*
1379	* OK, now the LEB is locked and we can safely start moving it. Since
1380	* this function utilizes the @ubi->peb_buf buffer which is shared
1381	* with some other functions - we lock the buffer by taking the
1382	* @ubi->buf_mutex.
1383	*/
1384	mutex_lock(&ubi->buf_mutex);
1385	dbg_wl("read %d bytes of data", aldata_size);
1386	err = ubi_io_read_data(ubi, buf: ubi->peb_buf, pnum: from, offset: 0, len: aldata_size);
1387	if (err && err != UBI_IO_BITFLIPS) {
1388	ubi_warn(ubi, fmt: "error %d while reading data from PEB %d",
1389	err, from);
1390	err = MOVE_SOURCE_RD_ERR;
1391	goto out_unlock_buf;
1392	}
1393
1394	/*
1395	* Now we have got to calculate how much data we have to copy. In
1396	* case of a static volume it is fairly easy - the VID header contains
1397	* the data size. In case of a dynamic volume it is more difficult - we
1398	* have to read the contents, cut 0xFF bytes from the end and copy only
1399	* the first part. We must do this to avoid writing 0xFF bytes as it
1400	* may have some side-effects. And not only this. It is important not
1401	* to include those 0xFFs to CRC because later the they may be filled
1402	* by data.
1403	*/
1404	if (vid_hdr->vol_type == UBI_VID_DYNAMIC)
1405	aldata_size = data_size =
1406	ubi_calc_data_len(ubi, buf: ubi->peb_buf, length: data_size);
1407
1408	cond_resched();
1409	crc = crc32(UBI_CRC32_INIT, ubi->peb_buf, data_size);
1410	cond_resched();
1411
1412	/*
1413	* It may turn out to be that the whole @from physical eraseblock
1414	* contains only 0xFF bytes. Then we have to only write the VID header
1415	* and do not write any data. This also means we should not set
1416	* @vid_hdr->copy_flag, @vid_hdr->data_size, and @vid_hdr->data_crc.
1417	*/
1418	if (data_size > 0) {
1419	vid_hdr->copy_flag = 1;
1420	vid_hdr->data_size = cpu_to_be32(data_size);
1421	vid_hdr->data_crc = cpu_to_be32(crc);
1422	}
1423	vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
1424
1425	err = ubi_io_write_vid_hdr(ubi, pnum: to, vidb);
1426	if (err) {
1427	if (err == -EIO)
1428	err = MOVE_TARGET_WR_ERR;
1429	goto out_unlock_buf;
1430	}
1431
1432	cond_resched();
1433
1434	/* Read the VID header back and check if it was written correctly */
1435	err = ubi_io_read_vid_hdr(ubi, pnum: to, vidb, verbose: 1);
1436	if (err) {
1437	if (err != UBI_IO_BITFLIPS) {
1438	ubi_warn(ubi, fmt: "error %d while reading VID header back from PEB %d",
1439	err, to);
1440	if (is_error_sane(err))
1441	err = MOVE_TARGET_RD_ERR;
1442	} else
1443	err = MOVE_TARGET_BITFLIPS;
1444	goto out_unlock_buf;
1445	}
1446
1447	if (data_size > 0) {
1448	err = ubi_io_write_data(ubi, buf: ubi->peb_buf, pnum: to, offset: 0, len: aldata_size);
1449	if (err) {
1450	if (err == -EIO)
1451	err = MOVE_TARGET_WR_ERR;
1452	goto out_unlock_buf;
1453	}
1454
1455	cond_resched();
1456	}
1457
1458	ubi_assert(vol->eba_tbl->entries[lnum].pnum == from);
1459
1460	/**
1461	* The volumes_lock lock is needed here to prevent the expired old eba_tbl
1462	* being updated when the eba_tbl is copied in the ubi_resize_volume() process.
1463	*/
1464	spin_lock(lock: &ubi->volumes_lock);
1465	vol->eba_tbl->entries[lnum].pnum = to;
1466	spin_unlock(lock: &ubi->volumes_lock);
1467
1468	out_unlock_buf:
1469	mutex_unlock(lock: &ubi->buf_mutex);
1470	out_unlock_leb:
1471	leb_write_unlock(ubi, vol_id, lnum);
1472	return err;
1473	}
1474
1475	/**
1476	* print_rsvd_warning - warn about not having enough reserved PEBs.
1477	* @ubi: UBI device description object
1478	* @ai: UBI attach info object
1479	*
1480	* This is a helper function for 'ubi_eba_init()' which is called when UBI
1481	* cannot reserve enough PEBs for bad block handling. This function makes a
1482	* decision whether we have to print a warning or not. The algorithm is as
1483	* follows:
1484	* o if this is a new UBI image, then just print the warning
1485	* o if this is an UBI image which has already been used for some time, print
1486	* a warning only if we can reserve less than 10% of the expected amount of
1487	* the reserved PEB.
1488	*
1489	* The idea is that when UBI is used, PEBs become bad, and the reserved pool
1490	* of PEBs becomes smaller, which is normal and we do not want to scare users
1491	* with a warning every time they attach the MTD device. This was an issue
1492	* reported by real users.
1493	*/
1494	static void print_rsvd_warning(struct ubi_device *ubi,
1495	struct ubi_attach_info *ai)
1496	{
1497	/*
1498	* The 1 << 18 (256KiB) number is picked randomly, just a reasonably
1499	* large number to distinguish between newly flashed and used images.
1500	*/
1501	if (ai->max_sqnum > (1 << 18)) {
1502	int min = ubi->beb_rsvd_level / 10;
1503
1504	if (!min)
1505	min = 1;
1506	if (ubi->beb_rsvd_pebs > min)
1507	return;
1508	}
1509
1510	ubi_warn(ubi, fmt: "cannot reserve enough PEBs for bad PEB handling, reserved %d, need %d",
1511	ubi->beb_rsvd_pebs, ubi->beb_rsvd_level);
1512	if (ubi->corr_peb_count)
1513	ubi_warn(ubi, fmt: "%d PEBs are corrupted and not used",
1514	ubi->corr_peb_count);
1515	}
1516
1517	/**
1518	* self_check_eba - run a self check on the EBA table constructed by fastmap.
1519	* @ubi: UBI device description object
1520	* @ai_fastmap: UBI attach info object created by fastmap
1521	* @ai_scan: UBI attach info object created by scanning
1522	*
1523	* Returns < 0 in case of an internal error, 0 otherwise.
1524	* If a bad EBA table entry was found it will be printed out and
1525	* ubi_assert() triggers.
1526	*/
1527	int self_check_eba(struct ubi_device *ubi, struct ubi_attach_info *ai_fastmap,
1528	struct ubi_attach_info *ai_scan)
1529	{
1530	int i, j, num_volumes, ret = 0;
1531	int **scan_eba, **fm_eba;
1532	struct ubi_ainf_volume *av;
1533	struct ubi_volume *vol;
1534	struct ubi_ainf_peb *aeb;
1535	struct rb_node *rb;
1536
1537	num_volumes = ubi->vtbl_slots + UBI_INT_VOL_COUNT;
1538
1539	scan_eba = kmalloc_array(n: num_volumes, size: sizeof(*scan_eba), GFP_KERNEL);
1540	if (!scan_eba)
1541	return -ENOMEM;
1542
1543	fm_eba = kmalloc_array(n: num_volumes, size: sizeof(*fm_eba), GFP_KERNEL);
1544	if (!fm_eba) {
1545	kfree(objp: scan_eba);
1546	return -ENOMEM;
1547	}
1548
1549	for (i = 0; i < num_volumes; i++) {
1550	vol = ubi->volumes[i];
1551	if (!vol)
1552	continue;
1553
1554	scan_eba[i] = kmalloc_array(n: vol->reserved_pebs,
1555	size: sizeof(**scan_eba),
1556	GFP_KERNEL);
1557	if (!scan_eba[i]) {
1558	ret = -ENOMEM;
1559	goto out_free;
1560	}
1561
1562	fm_eba[i] = kmalloc_array(n: vol->reserved_pebs,
1563	size: sizeof(**fm_eba),
1564	GFP_KERNEL);
1565	if (!fm_eba[i]) {
1566	ret = -ENOMEM;
1567	goto out_free;
1568	}
1569
1570	for (j = 0; j < vol->reserved_pebs; j++)
1571	scan_eba[i][j] = fm_eba[i][j] = UBI_LEB_UNMAPPED;
1572
1573	av = ubi_find_av(ai: ai_scan, vol_id: idx2vol_id(ubi, idx: i));
1574	if (!av)
1575	continue;
1576
1577	ubi_rb_for_each_entry(rb, aeb, &av->root, u.rb)
1578	scan_eba[i][aeb->lnum] = aeb->pnum;
1579
1580	av = ubi_find_av(ai: ai_fastmap, vol_id: idx2vol_id(ubi, idx: i));
1581	if (!av)
1582	continue;
1583
1584	ubi_rb_for_each_entry(rb, aeb, &av->root, u.rb)
1585	fm_eba[i][aeb->lnum] = aeb->pnum;
1586
1587	for (j = 0; j < vol->reserved_pebs; j++) {
1588	if (scan_eba[i][j] != fm_eba[i][j]) {
1589	if (scan_eba[i][j] == UBI_LEB_UNMAPPED ||
1590	fm_eba[i][j] == UBI_LEB_UNMAPPED)
1591	continue;
1592
1593	ubi_err(ubi, fmt: "LEB:%i:%i is PEB:%i instead of %i!",
1594	vol->vol_id, j, fm_eba[i][j],
1595	scan_eba[i][j]);
1596	ubi_assert(0);
1597	}
1598	}
1599	}
1600
1601	out_free:
1602	for (i = 0; i < num_volumes; i++) {
1603	if (!ubi->volumes[i])
1604	continue;
1605
1606	kfree(objp: scan_eba[i]);
1607	kfree(objp: fm_eba[i]);
1608	}
1609
1610	kfree(objp: scan_eba);
1611	kfree(objp: fm_eba);
1612	return ret;
1613	}
1614
1615	/**
1616	* ubi_eba_init - initialize the EBA sub-system using attaching information.
1617	* @ubi: UBI device description object
1618	* @ai: attaching information
1619	*
1620	* This function returns zero in case of success and a negative error code in
1621	* case of failure.
1622	*/
1623	int ubi_eba_init(struct ubi_device *ubi, struct ubi_attach_info *ai)
1624	{
1625	int i, err, num_volumes;
1626	struct ubi_ainf_volume *av;
1627	struct ubi_volume *vol;
1628	struct ubi_ainf_peb *aeb;
1629	struct rb_node *rb;
1630
1631	dbg_eba("initialize EBA sub-system");
1632
1633	spin_lock_init(&ubi->ltree_lock);
1634	mutex_init(&ubi->alc_mutex);
1635	ubi->ltree = RB_ROOT;
1636
1637	ubi->global_sqnum = ai->max_sqnum + 1;
1638	num_volumes = ubi->vtbl_slots + UBI_INT_VOL_COUNT;
1639
1640	for (i = 0; i < num_volumes; i++) {
1641	struct ubi_eba_table *tbl;
1642
1643	vol = ubi->volumes[i];
1644	if (!vol)
1645	continue;
1646
1647	cond_resched();
1648
1649	tbl = ubi_eba_create_table(vol, nentries: vol->reserved_pebs);
1650	if (IS_ERR(ptr: tbl)) {
1651	err = PTR_ERR(ptr: tbl);
1652	goto out_free;
1653	}
1654
1655	ubi_eba_replace_table(vol, tbl);
1656
1657	av = ubi_find_av(ai, vol_id: idx2vol_id(ubi, idx: i));
1658	if (!av)
1659	continue;
1660
1661	ubi_rb_for_each_entry(rb, aeb, &av->root, u.rb) {
1662	if (aeb->lnum >= vol->reserved_pebs) {
1663	/*
1664	* This may happen in case of an unclean reboot
1665	* during re-size.
1666	*/
1667	ubi_move_aeb_to_list(av, aeb, list: &ai->erase);
1668	} else {
1669	struct ubi_eba_entry *entry;
1670
1671	entry = &vol->eba_tbl->entries[aeb->lnum];
1672	entry->pnum = aeb->pnum;
1673	}
1674	}
1675	}
1676
1677	if (ubi->avail_pebs < EBA_RESERVED_PEBS) {
1678	ubi_err(ubi, fmt: "no enough physical eraseblocks (%d, need %d)",
1679	ubi->avail_pebs, EBA_RESERVED_PEBS);
1680	if (ubi->corr_peb_count)
1681	ubi_err(ubi, fmt: "%d PEBs are corrupted and not used",
1682	ubi->corr_peb_count);
1683	err = -ENOSPC;
1684	goto out_free;
1685	}
1686	ubi->avail_pebs -= EBA_RESERVED_PEBS;
1687	ubi->rsvd_pebs += EBA_RESERVED_PEBS;
1688
1689	if (ubi->bad_allowed) {
1690	ubi_calculate_reserved(ubi);
1691
1692	if (ubi->avail_pebs < ubi->beb_rsvd_level) {
1693	/* No enough free physical eraseblocks */
1694	ubi->beb_rsvd_pebs = ubi->avail_pebs;
1695	print_rsvd_warning(ubi, ai);
1696	} else
1697	ubi->beb_rsvd_pebs = ubi->beb_rsvd_level;
1698
1699	ubi->avail_pebs -= ubi->beb_rsvd_pebs;
1700	ubi->rsvd_pebs += ubi->beb_rsvd_pebs;
1701	}
1702
1703	dbg_eba("EBA sub-system is initialized");
1704	return 0;
1705
1706	out_free:
1707	for (i = 0; i < num_volumes; i++) {
1708	if (!ubi->volumes[i])
1709	continue;
1710	ubi_eba_replace_table(vol: ubi->volumes[i], NULL);
1711	}
1712	return err;
1713	}
1714