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-rw-r--r--drivers/mtd/ubi/upd.c348
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1/*
2 * Copyright (c) International Business Machines Corp., 2006
3 * Copyright (c) Nokia Corporation, 2006
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
13 * the GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 *
19 * Author: Artem Bityutskiy (Битюцкий Артём)
20 *
21 * Jan 2007: Alexander Schmidt, hacked per-volume update.
22 */
23
24/*
25 * This file contains implementation of the volume update functionality.
26 *
27 * The update operation is based on the per-volume update marker which is
28 * stored in the volume table. The update marker is set before the update
29 * starts, and removed after the update has been finished. So if the update was
30 * interrupted by an unclean re-boot or due to some other reasons, the update
31 * marker stays on the flash media and UBI finds it when it attaches the MTD
32 * device next time. If the update marker is set for a volume, the volume is
33 * treated as damaged and most I/O operations are prohibited. Only a new update
34 * operation is allowed.
35 *
36 * Note, in general it is possible to implement the update operation as a
37 * transaction with a roll-back capability.
38 */
39
40#include <linux/err.h>
41#include <asm/uaccess.h>
42#include <asm/div64.h>
43#include "ubi.h"
44
45/**
46 * set_update_marker - set update marker.
47 * @ubi: UBI device description object
48 * @vol_id: volume ID
49 *
50 * This function sets the update marker flag for volume @vol_id. Returns zero
51 * in case of success and a negative error code in case of failure.
52 */
53static int set_update_marker(struct ubi_device *ubi, int vol_id)
54{
55 int err;
56 struct ubi_vtbl_record vtbl_rec;
57 struct ubi_volume *vol = ubi->volumes[vol_id];
58
59 dbg_msg("set update marker for volume %d", vol_id);
60
61 if (vol->upd_marker) {
62 ubi_assert(ubi->vtbl[vol_id].upd_marker);
63 dbg_msg("already set");
64 return 0;
65 }
66
67 memcpy(&vtbl_rec, &ubi->vtbl[vol_id], sizeof(struct ubi_vtbl_record));
68 vtbl_rec.upd_marker = 1;
69
70 err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
71 vol->upd_marker = 1;
72 return err;
73}
74
75/**
76 * clear_update_marker - clear update marker.
77 * @ubi: UBI device description object
78 * @vol_id: volume ID
79 * @bytes: new data size in bytes
80 *
81 * This function clears the update marker for volume @vol_id, sets new volume
82 * data size and clears the "corrupted" flag (static volumes only). Returns
83 * zero in case of success and a negative error code in case of failure.
84 */
85static int clear_update_marker(struct ubi_device *ubi, int vol_id, long long bytes)
86{
87 int err;
88 uint64_t tmp;
89 struct ubi_vtbl_record vtbl_rec;
90 struct ubi_volume *vol = ubi->volumes[vol_id];
91
92 dbg_msg("clear update marker for volume %d", vol_id);
93
94 memcpy(&vtbl_rec, &ubi->vtbl[vol_id], sizeof(struct ubi_vtbl_record));
95 ubi_assert(vol->upd_marker && vtbl_rec.upd_marker);
96 vtbl_rec.upd_marker = 0;
97
98 if (vol->vol_type == UBI_STATIC_VOLUME) {
99 vol->corrupted = 0;
100 vol->used_bytes = tmp = bytes;
101 vol->last_eb_bytes = do_div(tmp, vol->usable_leb_size);
102 vol->used_ebs = tmp;
103 if (vol->last_eb_bytes)
104 vol->used_ebs += 1;
105 else
106 vol->last_eb_bytes = vol->usable_leb_size;
107 }
108
109 err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
110 vol->upd_marker = 0;
111 return err;
112}
113
114/**
115 * ubi_start_update - start volume update.
116 * @ubi: UBI device description object
117 * @vol_id: volume ID
118 * @bytes: update bytes
119 *
120 * This function starts volume update operation. If @bytes is zero, the volume
121 * is just wiped out. Returns zero in case of success and a negative error code
122 * in case of failure.
123 */
124int ubi_start_update(struct ubi_device *ubi, int vol_id, long long bytes)
125{
126 int i, err;
127 uint64_t tmp;
128 struct ubi_volume *vol = ubi->volumes[vol_id];
129
130 dbg_msg("start update of volume %d, %llu bytes", vol_id, bytes);
131 vol->updating = 1;
132
133 err = set_update_marker(ubi, vol_id);
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_id, i);
140 if (err)
141 return err;
142 }
143
144 if (bytes == 0) {
145 err = clear_update_marker(ubi, vol_id, 0);
146 if (err)
147 return err;
148 err = ubi_wl_flush(ubi);
149 if (!err)
150 vol->updating = 0;
151 }
152
153 vol->upd_buf = kmalloc(ubi->leb_size, GFP_KERNEL);
154 if (!vol->upd_buf)
155 return -ENOMEM;
156
157 tmp = bytes;
158 vol->upd_ebs = !!do_div(tmp, vol->usable_leb_size);
159 vol->upd_ebs += tmp;
160 vol->upd_bytes = bytes;
161 vol->upd_received = 0;
162 return 0;
163}
164
165/**
166 * write_leb - write update data.
167 * @ubi: UBI device description object
168 * @vol_id: volume ID
169 * @lnum: logical eraseblock number
170 * @buf: data to write
171 * @len: data size
172 * @used_ebs: how many logical eraseblocks will this volume contain (static
173 * volumes only)
174 *
175 * This function writes update data to corresponding logical eraseblock. In
176 * case of dynamic volume, this function checks if the data contains 0xFF bytes
177 * at the end. If yes, the 0xFF bytes are cut and not written. So if the whole
178 * buffer contains only 0xFF bytes, the LEB is left unmapped.
179 *
180 * The reason why we skip the trailing 0xFF bytes in case of dynamic volume is
181 * that we want to make sure that more data may be appended to the logical
182 * eraseblock in future. Indeed, writing 0xFF bytes may have side effects and
183 * this PEB won't be writable anymore. So if one writes the file-system image
184 * to the UBI volume where 0xFFs mean free space - UBI makes sure this free
185 * space is writable after the update.
186 *
187 * We do not do this for static volumes because they are read-only. But this
188 * also cannot be done because we have to store per-LEB CRC and the correct
189 * data length.
190 *
191 * This function returns zero in case of success and a negative error code in
192 * case of failure.
193 */
194static int write_leb(struct ubi_device *ubi, int vol_id, int lnum, void *buf,
195 int len, int used_ebs)
196{
197 int err, l;
198 struct ubi_volume *vol = ubi->volumes[vol_id];
199
200 if (vol->vol_type == UBI_DYNAMIC_VOLUME) {
201 l = ALIGN(len, ubi->min_io_size);
202 memset(buf + len, 0xFF, l - len);
203
204 l = ubi_calc_data_len(ubi, buf, l);
205 if (l == 0) {
206 dbg_msg("all %d bytes contain 0xFF - skip", len);
207 return 0;
208 }
209 if (len != l)
210 dbg_msg("skip last %d bytes (0xFF)", len - l);
211
212 err = ubi_eba_write_leb(ubi, vol_id, lnum, buf, 0, l,
213 UBI_UNKNOWN);
214 } else {
215 /*
216 * When writing static volume, and this is the last logical
217 * eraseblock, the length (@len) does not have to be aligned to
218 * the minimal flash I/O unit. The 'ubi_eba_write_leb_st()'
219 * function accepts exact (unaligned) length and stores it in
220 * the VID header. And it takes care of proper alignment by
221 * padding the buffer. Here we just make sure the padding will
222 * contain zeros, not random trash.
223 */
224 memset(buf + len, 0, vol->usable_leb_size - len);
225 err = ubi_eba_write_leb_st(ubi, vol_id, lnum, buf, len,
226 UBI_UNKNOWN, used_ebs);
227 }
228
229 return err;
230}
231
232/**
233 * ubi_more_update_data - write more update data.
234 * @vol: volume description object
235 * @buf: write data (user-space memory buffer)
236 * @count: how much bytes to write
237 *
238 * This function writes more data to the volume which is being updated. It may
239 * be called arbitrary number of times until all of the update data arrive.
240 * This function returns %0 in case of success, number of bytes written during
241 * the last call if the whole volume update was successfully finished, and a
242 * negative error code in case of failure.
243 */
244int ubi_more_update_data(struct ubi_device *ubi, int vol_id,
245 const void __user *buf, int count)
246{
247 uint64_t tmp;
248 struct ubi_volume *vol = ubi->volumes[vol_id];
249 int lnum, offs, err = 0, len, to_write = count;
250
251 dbg_msg("write %d of %lld bytes, %lld already passed",
252 count, vol->upd_bytes, vol->upd_received);
253
254 if (ubi->ro_mode)
255 return -EROFS;
256
257 tmp = vol->upd_received;
258 offs = do_div(tmp, vol->usable_leb_size);
259 lnum = tmp;
260
261 if (vol->upd_received + count > vol->upd_bytes)
262 to_write = count = vol->upd_bytes - vol->upd_received;
263
264 /*
265 * When updating volumes, we accumulate whole logical eraseblock of
266 * data and write it at once.
267 */
268 if (offs != 0) {
269 /*
270 * This is a write to the middle of the logical eraseblock. We
271 * copy the data to our update buffer and wait for more data or
272 * flush it if the whole eraseblock is written or the update
273 * is finished.
274 */
275
276 len = vol->usable_leb_size - offs;
277 if (len > count)
278 len = count;
279
280 err = copy_from_user(vol->upd_buf + offs, buf, len);
281 if (err)
282 return -EFAULT;
283
284 if (offs + len == vol->usable_leb_size ||
285 vol->upd_received + len == vol->upd_bytes) {
286 int flush_len = offs + len;
287
288 /*
289 * OK, we gathered either the whole eraseblock or this
290 * is the last chunk, it's time to flush the buffer.
291 */
292 ubi_assert(flush_len <= vol->usable_leb_size);
293 err = write_leb(ubi, vol_id, lnum, vol->upd_buf,
294 flush_len, vol->upd_ebs);
295 if (err)
296 return err;
297 }
298
299 vol->upd_received += len;
300 count -= len;
301 buf += len;
302 lnum += 1;
303 }
304
305 /*
306 * If we've got more to write, let's continue. At this point we know we
307 * are starting from the beginning of an eraseblock.
308 */
309 while (count) {
310 if (count > vol->usable_leb_size)
311 len = vol->usable_leb_size;
312 else
313 len = count;
314
315 err = copy_from_user(vol->upd_buf, buf, len);
316 if (err)
317 return -EFAULT;
318
319 if (len == vol->usable_leb_size ||
320 vol->upd_received + len == vol->upd_bytes) {
321 err = write_leb(ubi, vol_id, lnum, vol->upd_buf, len,
322 vol->upd_ebs);
323 if (err)
324 break;
325 }
326
327 vol->upd_received += len;
328 count -= len;
329 lnum += 1;
330 buf += len;
331 }
332
333 ubi_assert(vol->upd_received <= vol->upd_bytes);
334 if (vol->upd_received == vol->upd_bytes) {
335 /* The update is finished, clear the update marker */
336 err = clear_update_marker(ubi, vol_id, vol->upd_bytes);
337 if (err)
338 return err;
339 err = ubi_wl_flush(ubi);
340 if (err == 0) {
341 err = to_write;
342 kfree(vol->upd_buf);
343 vol->updating = 0;
344 }
345 }
346
347 return err;
348}