1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Copyright (c) International Business Machines Corp., 2006
4 * Copyright (c) Nokia Corporation, 2006
5 *
6 * Author: Artem Bityutskiy (Битюцкий Артём)
7 *
8 * Jan 2007: Alexander Schmidt, hacked per-volume update.
9 */
10
11 /*
12 * This file contains implementation of the volume update and atomic LEB change
13 * functionality.
14 *
15 * The update operation is based on the per-volume update marker which is
16 * stored in the volume table. The update marker is set before the update
17 * starts, and removed after the update has been finished. So if the update was
18 * interrupted by an unclean re-boot or due to some other reasons, the update
19 * marker stays on the flash media and UBI finds it when it attaches the MTD
20 * device next time. If the update marker is set for a volume, the volume is
21 * treated as damaged and most I/O operations are prohibited. Only a new update
22 * operation is allowed.
23 *
24 * Note, in general it is possible to implement the update operation as a
25 * transaction with a roll-back capability.
26 */
27
28 #ifndef __UBOOT__
29 #include <linux/uaccess.h>
30 #else
31 #include <div64.h>
32 #include <ubi_uboot.h>
33 #endif
34 #include <linux/err.h>
35 #include <linux/math64.h>
36
37 #include "ubi.h"
38
39 /**
40 * set_update_marker - set update marker.
41 * @ubi: UBI device description object
42 * @vol: volume description object
43 *
44 * This function sets the update marker flag for volume @vol. Returns zero
45 * in case of success and a negative error code in case of failure.
46 */
set_update_marker(struct ubi_device * ubi,struct ubi_volume * vol)47 static int set_update_marker(struct ubi_device *ubi, struct ubi_volume *vol)
48 {
49 int err;
50 struct ubi_vtbl_record vtbl_rec;
51
52 dbg_gen("set update marker for volume %d", vol->vol_id);
53
54 if (vol->upd_marker) {
55 ubi_assert(ubi->vtbl[vol->vol_id].upd_marker);
56 dbg_gen("already set");
57 return 0;
58 }
59
60 vtbl_rec = ubi->vtbl[vol->vol_id];
61 vtbl_rec.upd_marker = 1;
62
63 mutex_lock(&ubi->device_mutex);
64 err = ubi_change_vtbl_record(ubi, vol->vol_id, &vtbl_rec);
65 vol->upd_marker = 1;
66 mutex_unlock(&ubi->device_mutex);
67 return err;
68 }
69
70 /**
71 * clear_update_marker - clear update marker.
72 * @ubi: UBI device description object
73 * @vol: volume description object
74 * @bytes: new data size in bytes
75 *
76 * This function clears the update marker for volume @vol, sets new volume
77 * data size and clears the "corrupted" flag (static volumes only). Returns
78 * zero in case of success and a negative error code in case of failure.
79 */
clear_update_marker(struct ubi_device * ubi,struct ubi_volume * vol,long long bytes)80 static int clear_update_marker(struct ubi_device *ubi, struct ubi_volume *vol,
81 long long bytes)
82 {
83 int err;
84 struct ubi_vtbl_record vtbl_rec;
85
86 dbg_gen("clear update marker for volume %d", vol->vol_id);
87
88 vtbl_rec = ubi->vtbl[vol->vol_id];
89 ubi_assert(vol->upd_marker && vtbl_rec.upd_marker);
90 vtbl_rec.upd_marker = 0;
91
92 if (vol->vol_type == UBI_STATIC_VOLUME) {
93 vol->corrupted = 0;
94 vol->used_bytes = bytes;
95 vol->used_ebs = div_u64_rem(bytes, vol->usable_leb_size,
96 &vol->last_eb_bytes);
97 if (vol->last_eb_bytes)
98 vol->used_ebs += 1;
99 else
100 vol->last_eb_bytes = vol->usable_leb_size;
101 }
102
103 mutex_lock(&ubi->device_mutex);
104 err = ubi_change_vtbl_record(ubi, vol->vol_id, &vtbl_rec);
105 vol->upd_marker = 0;
106 mutex_unlock(&ubi->device_mutex);
107 return err;
108 }
109
110 /**
111 * ubi_start_update - start volume update.
112 * @ubi: UBI device description object
113 * @vol: volume description object
114 * @bytes: update bytes
115 *
116 * This function starts volume update operation. If @bytes is zero, the volume
117 * is just wiped out. Returns zero in case of success and a negative error code
118 * in case of failure.
119 */
ubi_start_update(struct ubi_device * ubi,struct ubi_volume * vol,long long bytes)120 int ubi_start_update(struct ubi_device *ubi, struct ubi_volume *vol,
121 long long bytes)
122 {
123 int i, err;
124
125 dbg_gen("start update of volume %d, %llu bytes", vol->vol_id, bytes);
126 ubi_assert(!vol->updating && !vol->changing_leb);
127 vol->updating = 1;
128
129 vol->upd_buf = vmalloc(ubi->leb_size);
130 if (!vol->upd_buf)
131 return -ENOMEM;
132
133 err = set_update_marker(ubi, vol);
134 if (err)
135 return err;
136
137 /* Before updating - wipe out the volume */
138 for (i = 0; i < vol->reserved_pebs; i++) {
139 err = ubi_eba_unmap_leb(ubi, vol, i);
140 if (err)
141 return err;
142 }
143
144 if (bytes == 0) {
145 err = ubi_wl_flush(ubi, UBI_ALL, UBI_ALL);
146 if (err)
147 return err;
148
149 err = clear_update_marker(ubi, vol, 0);
150 if (err)
151 return err;
152
153 vfree(vol->upd_buf);
154 vol->updating = 0;
155 return 0;
156 }
157
158 vol->upd_ebs = div_u64(bytes + vol->usable_leb_size - 1,
159 vol->usable_leb_size);
160 vol->upd_bytes = bytes;
161 vol->upd_received = 0;
162 return 0;
163 }
164
165 /**
166 * ubi_start_leb_change - start atomic LEB change.
167 * @ubi: UBI device description object
168 * @vol: volume description object
169 * @req: operation request
170 *
171 * This function starts atomic LEB change operation. Returns zero in case of
172 * success and a negative error code in case of failure.
173 */
ubi_start_leb_change(struct ubi_device * ubi,struct ubi_volume * vol,const struct ubi_leb_change_req * req)174 int ubi_start_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
175 const struct ubi_leb_change_req *req)
176 {
177 ubi_assert(!vol->updating && !vol->changing_leb);
178
179 dbg_gen("start changing LEB %d:%d, %u bytes",
180 vol->vol_id, req->lnum, req->bytes);
181 if (req->bytes == 0)
182 return ubi_eba_atomic_leb_change(ubi, vol, req->lnum, NULL, 0);
183
184 vol->upd_bytes = req->bytes;
185 vol->upd_received = 0;
186 vol->changing_leb = 1;
187 vol->ch_lnum = req->lnum;
188
189 vol->upd_buf = vmalloc(req->bytes);
190 if (!vol->upd_buf)
191 return -ENOMEM;
192
193 return 0;
194 }
195
196 /**
197 * write_leb - write update data.
198 * @ubi: UBI device description object
199 * @vol: volume description object
200 * @lnum: logical eraseblock number
201 * @buf: data to write
202 * @len: data size
203 * @used_ebs: how many logical eraseblocks will this volume contain (static
204 * volumes only)
205 *
206 * This function writes update data to corresponding logical eraseblock. In
207 * case of dynamic volume, this function checks if the data contains 0xFF bytes
208 * at the end. If yes, the 0xFF bytes are cut and not written. So if the whole
209 * buffer contains only 0xFF bytes, the LEB is left unmapped.
210 *
211 * The reason why we skip the trailing 0xFF bytes in case of dynamic volume is
212 * that we want to make sure that more data may be appended to the logical
213 * eraseblock in future. Indeed, writing 0xFF bytes may have side effects and
214 * this PEB won't be writable anymore. So if one writes the file-system image
215 * to the UBI volume where 0xFFs mean free space - UBI makes sure this free
216 * space is writable after the update.
217 *
218 * We do not do this for static volumes because they are read-only. But this
219 * also cannot be done because we have to store per-LEB CRC and the correct
220 * data length.
221 *
222 * This function returns zero in case of success and a negative error code in
223 * case of failure.
224 */
write_leb(struct ubi_device * ubi,struct ubi_volume * vol,int lnum,void * buf,int len,int used_ebs)225 static int write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
226 void *buf, int len, int used_ebs)
227 {
228 int err;
229
230 if (vol->vol_type == UBI_DYNAMIC_VOLUME) {
231 int l = ALIGN(len, ubi->min_io_size);
232
233 memset(buf + len, 0xFF, l - len);
234 len = ubi_calc_data_len(ubi, buf, l);
235 if (len == 0) {
236 dbg_gen("all %d bytes contain 0xFF - skip", len);
237 return 0;
238 }
239
240 err = ubi_eba_write_leb(ubi, vol, lnum, buf, 0, len);
241 } else {
242 /*
243 * When writing static volume, and this is the last logical
244 * eraseblock, the length (@len) does not have to be aligned to
245 * the minimal flash I/O unit. The 'ubi_eba_write_leb_st()'
246 * function accepts exact (unaligned) length and stores it in
247 * the VID header. And it takes care of proper alignment by
248 * padding the buffer. Here we just make sure the padding will
249 * contain zeros, not random trash.
250 */
251 memset(buf + len, 0, vol->usable_leb_size - len);
252 err = ubi_eba_write_leb_st(ubi, vol, lnum, buf, len, used_ebs);
253 }
254
255 return err;
256 }
257
258 /**
259 * ubi_more_update_data - write more update data.
260 * @ubi: UBI device description object
261 * @vol: volume description object
262 * @buf: write data (user-space memory buffer)
263 * @count: how much bytes to write
264 *
265 * This function writes more data to the volume which is being updated. It may
266 * be called arbitrary number of times until all the update data arriveis. This
267 * function returns %0 in case of success, number of bytes written during the
268 * last call if the whole volume update has been successfully finished, and a
269 * negative error code in case of failure.
270 */
ubi_more_update_data(struct ubi_device * ubi,struct ubi_volume * vol,const void __user * buf,int count)271 int ubi_more_update_data(struct ubi_device *ubi, struct ubi_volume *vol,
272 const void __user *buf, int count)
273 {
274 #ifndef __UBOOT__
275 int lnum, offs, err = 0, len, to_write = count;
276 #else
277 int lnum, err = 0, len, to_write = count;
278 u32 offs;
279 #endif
280
281 dbg_gen("write %d of %lld bytes, %lld already passed",
282 count, vol->upd_bytes, vol->upd_received);
283
284 if (ubi->ro_mode)
285 return -EROFS;
286
287 lnum = div_u64_rem(vol->upd_received, vol->usable_leb_size, &offs);
288 if (vol->upd_received + count > vol->upd_bytes)
289 to_write = count = vol->upd_bytes - vol->upd_received;
290
291 /*
292 * When updating volumes, we accumulate whole logical eraseblock of
293 * data and write it at once.
294 */
295 if (offs != 0) {
296 /*
297 * This is a write to the middle of the logical eraseblock. We
298 * copy the data to our update buffer and wait for more data or
299 * flush it if the whole eraseblock is written or the update
300 * is finished.
301 */
302
303 len = vol->usable_leb_size - offs;
304 if (len > count)
305 len = count;
306
307 err = copy_from_user(vol->upd_buf + offs, buf, len);
308 if (err)
309 return -EFAULT;
310
311 if (offs + len == vol->usable_leb_size ||
312 vol->upd_received + len == vol->upd_bytes) {
313 int flush_len = offs + len;
314
315 /*
316 * OK, we gathered either the whole eraseblock or this
317 * is the last chunk, it's time to flush the buffer.
318 */
319 ubi_assert(flush_len <= vol->usable_leb_size);
320 err = write_leb(ubi, vol, lnum, vol->upd_buf, flush_len,
321 vol->upd_ebs);
322 if (err)
323 return err;
324 }
325
326 vol->upd_received += len;
327 count -= len;
328 buf += len;
329 lnum += 1;
330 }
331
332 /*
333 * If we've got more to write, let's continue. At this point we know we
334 * are starting from the beginning of an eraseblock.
335 */
336 while (count) {
337 if (count > vol->usable_leb_size)
338 len = vol->usable_leb_size;
339 else
340 len = count;
341
342 err = copy_from_user(vol->upd_buf, buf, len);
343 if (err)
344 return -EFAULT;
345
346 if (len == vol->usable_leb_size ||
347 vol->upd_received + len == vol->upd_bytes) {
348 err = write_leb(ubi, vol, lnum, vol->upd_buf,
349 len, vol->upd_ebs);
350 if (err)
351 break;
352 }
353
354 vol->upd_received += len;
355 count -= len;
356 lnum += 1;
357 buf += len;
358 }
359
360 ubi_assert(vol->upd_received <= vol->upd_bytes);
361 if (vol->upd_received == vol->upd_bytes) {
362 err = ubi_wl_flush(ubi, UBI_ALL, UBI_ALL);
363 if (err)
364 return err;
365 /* The update is finished, clear the update marker */
366 err = clear_update_marker(ubi, vol, vol->upd_bytes);
367 if (err)
368 return err;
369 vol->updating = 0;
370 err = to_write;
371 vfree(vol->upd_buf);
372 }
373
374 return err;
375 }
376
377 /**
378 * ubi_more_leb_change_data - accept more data for atomic LEB change.
379 * @ubi: UBI device description object
380 * @vol: volume description object
381 * @buf: write data (user-space memory buffer)
382 * @count: how much bytes to write
383 *
384 * This function accepts more data to the volume which is being under the
385 * "atomic LEB change" operation. It may be called arbitrary number of times
386 * until all data arrives. This function returns %0 in case of success, number
387 * of bytes written during the last call if the whole "atomic LEB change"
388 * operation has been successfully finished, and a negative error code in case
389 * of failure.
390 */
ubi_more_leb_change_data(struct ubi_device * ubi,struct ubi_volume * vol,const void __user * buf,int count)391 int ubi_more_leb_change_data(struct ubi_device *ubi, struct ubi_volume *vol,
392 const void __user *buf, int count)
393 {
394 int err;
395
396 dbg_gen("write %d of %lld bytes, %lld already passed",
397 count, vol->upd_bytes, vol->upd_received);
398
399 if (ubi->ro_mode)
400 return -EROFS;
401
402 if (vol->upd_received + count > vol->upd_bytes)
403 count = vol->upd_bytes - vol->upd_received;
404
405 err = copy_from_user(vol->upd_buf + vol->upd_received, buf, count);
406 if (err)
407 return -EFAULT;
408
409 vol->upd_received += count;
410
411 if (vol->upd_received == vol->upd_bytes) {
412 int len = ALIGN((int)vol->upd_bytes, ubi->min_io_size);
413
414 memset(vol->upd_buf + vol->upd_bytes, 0xFF,
415 len - vol->upd_bytes);
416 len = ubi_calc_data_len(ubi, vol->upd_buf, len);
417 err = ubi_eba_atomic_leb_change(ubi, vol, vol->ch_lnum,
418 vol->upd_buf, len);
419 if (err)
420 return err;
421 }
422
423 ubi_assert(vol->upd_received <= vol->upd_bytes);
424 if (vol->upd_received == vol->upd_bytes) {
425 vol->changing_leb = 0;
426 err = count;
427 vfree(vol->upd_buf);
428 }
429
430 return err;
431 }
432