aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/mtd/ubi/upd.c
blob: 8b89cc18ff0b69753326dbe48b87015726cf3cc1 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
/*
 * Copyright (c) International Business Machines Corp., 2006
 * Copyright (c) Nokia Corporation, 2006
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
 * the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * Author: Artem Bityutskiy (Битюцкий Артём)
 *
 * Jan 2007: Alexander Schmidt, hacked per-volume update.
 */

/*
 * This file contains implementation of the volume update and atomic LEB change
 * functionality.
 *
 * The update operation is based on the per-volume update marker which is
 * stored in the volume table. The update marker is set before the update
 * starts, and removed after the update has been finished. So if the update was
 * interrupted by an unclean re-boot or due to some other reasons, the update
 * marker stays on the flash media and UBI finds it when it attaches the MTD
 * device next time. If the update marker is set for a volume, the volume is
 * treated as damaged and most I/O operations are prohibited. Only a new update
 * operation is allowed.
 *
 * Note, in general it is possible to implement the update operation as a
 * transaction with a roll-back capability.
 */

#include <linux/err.h>
#include <linux/uaccess.h>
#include <asm/div64.h>
#include "ubi.h"

/**
 * set_update_marker - set update marker.
 * @ubi: UBI device description object
 * @vol: volume description object
 *
 * This function sets the update marker flag for volume @vol. Returns zero
 * in case of success and a negative error code in case of failure.
 */
static int set_update_marker(struct ubi_device *ubi, struct ubi_volume *vol)
{
	int err;
	struct ubi_vtbl_record vtbl_rec;

	dbg_gen("set update marker for volume %d", vol->vol_id);

	if (vol->upd_marker) {
		ubi_assert(ubi->vtbl[vol->vol_id].upd_marker);
		dbg_gen("already set");
		return 0;
	}

	memcpy(&vtbl_rec, &ubi->vtbl[vol->vol_id],
	       sizeof(struct ubi_vtbl_record));
	vtbl_rec.upd_marker = 1;

	mutex_lock(&ubi->volumes_mutex);
	err = ubi_change_vtbl_record(ubi, vol->vol_id, &vtbl_rec);
	mutex_unlock(&ubi->volumes_mutex);
	vol->upd_marker = 1;
	return err;
}

/**
 * clear_update_marker - clear update marker.
 * @ubi: UBI device description object
 * @vol: volume description object
 * @bytes: new data size in bytes
 *
 * This function clears the update marker for volume @vol, sets new volume
 * data size and clears the "corrupted" flag (static volumes only). Returns
 * zero in case of success and a negative error code in case of failure.
 */
static int clear_update_marker(struct ubi_device *ubi, struct ubi_volume *vol,
			       long long bytes)
{
	int err;
	uint64_t tmp;
	struct ubi_vtbl_record vtbl_rec;

	dbg_gen("clear update marker for volume %d", vol->vol_id);

	memcpy(&vtbl_rec, &ubi->vtbl[vol->vol_id],
	       sizeof(struct ubi_vtbl_record));
	ubi_assert(vol->upd_marker && vtbl_rec.upd_marker);
	vtbl_rec.upd_marker = 0;

	if (vol->vol_type == UBI_STATIC_VOLUME) {
		vol->corrupted = 0;
		vol->used_bytes = tmp = bytes;
		vol->last_eb_bytes = do_div(tmp, vol->usable_leb_size);
		vol->used_ebs = tmp;
		if (vol->last_eb_bytes)
			vol->used_ebs += 1;
		else
			vol->last_eb_bytes = vol->usable_leb_size;
	}

	mutex_lock(&ubi->volumes_mutex);
	err = ubi_change_vtbl_record(ubi, vol->vol_id, &vtbl_rec);
	mutex_unlock(&ubi->volumes_mutex);
	vol->upd_marker = 0;
	return err;
}

/**
 * ubi_start_update - start volume update.
 * @ubi: UBI device description object
 * @vol: volume description object
 * @bytes: update bytes
 *
 * This function starts volume update operation. If @bytes is zero, the volume
 * is just wiped out. Returns zero in case of success and a negative error code
 * in case of failure.
 */
int ubi_start_update(struct ubi_device *ubi, struct ubi_volume *vol,
		     long long bytes)
{
	int i, err;
	uint64_t tmp;

	dbg_gen("start update of volume %d, %llu bytes", vol->vol_id, bytes);
	ubi_assert(!vol->updating && !vol->changing_leb);
	vol->updating = 1;

	err = set_update_marker(ubi, vol);
	if (err)
		return err;

	/* Before updating - wipe out the volume */
	for (i = 0; i < vol->reserved_pebs; i++) {
		err = ubi_eba_unmap_leb(ubi, vol, i);
		if (err)
			return err;
	}

	if (bytes == 0) {
		err = clear_update_marker(ubi, vol, 0);
		if (err)
			return err;
		err = ubi_wl_flush(ubi);
		if (!err)
			vol->updating = 0;
	}

	vol->upd_buf = vmalloc(ubi->leb_size);
	if (!vol->upd_buf)
		return -ENOMEM;

	tmp = bytes;
	vol->upd_ebs = !!do_div(tmp, vol->usable_leb_size);
	vol->upd_ebs += tmp;
	vol->upd_bytes = bytes;
	vol->upd_received = 0;
	return 0;
}

/**
 * ubi_start_leb_change - start atomic LEB change.
 * @ubi: UBI device description object
 * @vol: volume description object
 * @req: operation request
 *
 * This function starts atomic LEB change operation. Returns zero in case of
 * success and a negative error code in case of failure.
 */
int ubi_start_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
			 const struct ubi_leb_change_req *req)
{
	ubi_assert(!vol->updating && !vol->changing_leb);

	dbg_gen("start changing LEB %d:%d, %u bytes",
		vol->vol_id, req->lnum, req->bytes);
	if (req->bytes == 0)
		return ubi_eba_atomic_leb_change(ubi, vol, req->lnum, NULL, 0,
						 req->dtype);

	vol->upd_bytes = req->bytes;
	vol->upd_received = 0;
	vol->changing_leb = 1;
	vol->ch_lnum = req->lnum;
	vol->ch_dtype = req->dtype;

	vol->upd_buf = vmalloc(req->bytes);
	if (!vol->upd_buf)
		return -ENOMEM;

	return 0;
}

/**
 * write_leb - write update data.
 * @ubi: UBI device description object
 * @vol: volume description object
 * @lnum: logical eraseblock number
 * @buf: data to write
 * @len: data size
 * @used_ebs: how many logical eraseblocks will this volume contain (static
 * volumes only)
 *
 * This function writes update data to corresponding logical eraseblock. In
 * case of dynamic volume, this function checks if the data contains 0xFF bytes
 * at the end. If yes, the 0xFF bytes are cut and not written. So if the whole
 * buffer contains only 0xFF bytes, the LEB is left unmapped.
 *
 * The reason why we skip the trailing 0xFF bytes in case of dynamic volume is
 * that we want to make sure that more data may be appended to the logical
 * eraseblock in future. Indeed, writing 0xFF bytes may have side effects and
 * this PEB won't be writable anymore. So if one writes the file-system image
 * to the UBI volume where 0xFFs mean free space - UBI makes sure this free
 * space is writable after the update.
 *
 * We do not do this for static volumes because they are read-only. But this
 * also cannot be done because we have to store per-LEB CRC and the correct
 * data length.
 *
 * This function returns zero in case of success and a negative error code in
 * case of failure.
 */
static int write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
		     void *buf, int len, int used_ebs)
{
	int err;

	if (vol->vol_type == UBI_DYNAMIC_VOLUME) {
		int l = ALIGN(len, ubi->min_io_size);

		memset(buf + len, 0xFF, l - len);
		len = ubi_calc_data_len(ubi, buf, l);
		if (len == 0) {
			dbg_gen("all %d bytes contain 0xFF - skip", len);
			return 0;
		}

		err = ubi_eba_write_leb(ubi, vol, lnum, buf, 0, len,
					UBI_UNKNOWN);
	} else {
		/*
		 * When writing static volume, and this is the last logical
		 * eraseblock, the length (@len) does not have to be aligned to
		 * the minimal flash I/O unit. The 'ubi_eba_write_leb_st()'
		 * function accepts exact (unaligned) length and stores it in
		 * the VID header. And it takes care of proper alignment by
		 * padding the buffer. Here we just make sure the padding will
		 * contain zeros, not random trash.
		 */
		memset(buf + len, 0, vol->usable_leb_size - len);
		err = ubi_eba_write_leb_st(ubi, vol, lnum, buf, len,
					   UBI_UNKNOWN, used_ebs);
	}

	return err;
}

/**
 * ubi_more_update_data - write more update data.
 * @ubi: UBI device description object
 * @vol: volume description object
 * @buf: write data (user-space memory buffer)
 * @count: how much bytes to write
 *
 * This function writes more data to the volume which is being updated. It may
 * be called arbitrary number of times until all the update data arriveis. This
 * function returns %0 in case of success, number of bytes written during the
 * last call if the whole volume update has been successfully finished, and a
 * negative error code in case of failure.
 */
int ubi_more_update_data(struct ubi_device *ubi, struct ubi_volume *vol,
			 const void __user *buf, int count)
{
	uint64_t tmp;
	int lnum, offs, err = 0, len, to_write = count;

	dbg_gen("write %d of %lld bytes, %lld already passed",
		count, vol->upd_bytes, vol->upd_received);

	if (ubi->ro_mode)
		return -EROFS;

	tmp = vol->upd_received;
	offs = do_div(tmp, vol->usable_leb_size);
	lnum = tmp;

	if (vol->upd_received + count > vol->upd_bytes)
		to_write = count = vol->upd_bytes - vol->upd_received;

	/*
	 * When updating volumes, we accumulate whole logical eraseblock of
	 * data and write it at once.
	 */
	if (offs != 0) {
		/*
		 * This is a write to the middle of the logical eraseblock. We
		 * copy the data to our update buffer and wait for more data or
		 * flush it if the whole eraseblock is written or the update
		 * is finished.
		 */

		len = vol->usable_leb_size - offs;
		if (len > count)
			len = count;

		err = copy_from_user(vol->upd_buf + offs, buf, len);
		if (err)
			return -EFAULT;

		if (offs + len == vol->usable_leb_size ||
		    vol->upd_received + len == vol->upd_bytes) {
			int flush_len = offs + len;

			/*
			 * OK, we gathered either the whole eraseblock or this
			 * is the last chunk, it's time to flush the buffer.
			 */
			ubi_assert(flush_len <= vol->usable_leb_size);
			err = write_leb(ubi, vol, lnum, vol->upd_buf, flush_len,
					vol->upd_ebs);
			if (err)
				return err;
		}

		vol->upd_received += len;
		count -= len;
		buf += len;
		lnum += 1;
	}

	/*
	 * If we've got more to write, let's continue. At this point we know we
	 * are starting from the beginning of an eraseblock.
	 */
	while (count) {
		if (count > vol->usable_leb_size)
			len = vol->usable_leb_size;
		else
			len = count;

		err = copy_from_user(vol->upd_buf, buf, len);
		if (err)
			return -EFAULT;

		if (len == vol->usable_leb_size ||
		    vol->upd_received + len == vol->upd_bytes) {
			err = write_leb(ubi, vol, lnum, vol->upd_buf,
					len, vol->upd_ebs);
			if (err)
				break;
		}

		vol->upd_received += len;
		count -= len;
		lnum += 1;
		buf += len;
	}

	ubi_assert(vol->upd_received <= vol->upd_bytes);
	if (vol->upd_received == vol->upd_bytes) {
		/* The update is finished, clear the update marker */
		err = clear_update_marker(ubi, vol, vol->upd_bytes);
		if (err)
			return err;
		err = ubi_wl_flush(ubi);
		if (err == 0) {
			vol->updating = 0;
			err = to_write;
			vfree(vol->upd_buf);
		}
	}

	return err;
}

/**
 * ubi_more_leb_change_data - accept more data for atomic LEB change.
 * @ubi: UBI device description object
 * @vol: volume description object
 * @buf: write data (user-space memory buffer)
 * @count: how much bytes to write
 *
 * This function accepts more data to the volume which is being under the
 * "atomic LEB change" operation. It may be called arbitrary number of times
 * until all data arrives. This function returns %0 in case of success, number
 * of bytes written during the last call if the whole "atomic LEB change"
 * operation has been successfully finished, and a negative error code in case
 * of failure.
 */
int ubi_more_leb_change_data(struct ubi_device *ubi, struct ubi_volume *vol,
			     const void __user *buf, int count)
{
	int err;

	dbg_gen("write %d of %lld bytes, %lld already passed",
		count, vol->upd_bytes, vol->upd_received);

	if (ubi->ro_mode)
		return -EROFS;

	if (vol->upd_received + count > vol->upd_bytes)
		count = vol->upd_bytes - vol->upd_received;

	err = copy_from_user(vol->upd_buf + vol->upd_received, buf, count);
	if (err)
		return -EFAULT;

	vol->upd_received += count;

	if (vol->upd_received == vol->upd_bytes) {
		int len = ALIGN((int)vol->upd_bytes, ubi->min_io_size);

		memset(vol->upd_buf + vol->upd_bytes, 0xFF,
		       len - vol->upd_bytes);
		len = ubi_calc_data_len(ubi, vol->upd_buf, len);
		err = ubi_eba_atomic_leb_change(ubi, vol, vol->ch_lnum,
						vol->upd_buf, len, UBI_UNKNOWN);
		if (err)
			return err;
	}

	ubi_assert(vol->upd_received <= vol->upd_bytes);
	if (vol->upd_received == vol->upd_bytes) {
		vol->changing_leb = 0;
		err = count;
		vfree(vol->upd_buf);
	}

	return err;
}