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801c135c AB |
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 | */ | |
53 | static 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 | */ | |
85 | static 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 | */ | |
124 | int 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++) { | |
89b96b69 | 139 | err = ubi_eba_unmap_leb(ubi, vol, i); |
801c135c AB |
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 | ||
92ad8f37 | 153 | vol->upd_buf = vmalloc(ubi->leb_size); |
801c135c AB |
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 | */ | |
194 | static 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 | ||
89b96b69 | 212 | err = ubi_eba_write_leb(ubi, vol, lnum, buf, 0, l, UBI_UNKNOWN); |
801c135c AB |
213 | } else { |
214 | /* | |
215 | * When writing static volume, and this is the last logical | |
216 | * eraseblock, the length (@len) does not have to be aligned to | |
217 | * the minimal flash I/O unit. The 'ubi_eba_write_leb_st()' | |
218 | * function accepts exact (unaligned) length and stores it in | |
219 | * the VID header. And it takes care of proper alignment by | |
220 | * padding the buffer. Here we just make sure the padding will | |
221 | * contain zeros, not random trash. | |
222 | */ | |
223 | memset(buf + len, 0, vol->usable_leb_size - len); | |
89b96b69 | 224 | err = ubi_eba_write_leb_st(ubi, vol, lnum, buf, len, |
801c135c AB |
225 | UBI_UNKNOWN, used_ebs); |
226 | } | |
227 | ||
228 | return err; | |
229 | } | |
230 | ||
231 | /** | |
232 | * ubi_more_update_data - write more update data. | |
233 | * @vol: volume description object | |
234 | * @buf: write data (user-space memory buffer) | |
235 | * @count: how much bytes to write | |
236 | * | |
237 | * This function writes more data to the volume which is being updated. It may | |
238 | * be called arbitrary number of times until all of the update data arrive. | |
239 | * This function returns %0 in case of success, number of bytes written during | |
240 | * the last call if the whole volume update was successfully finished, and a | |
241 | * negative error code in case of failure. | |
242 | */ | |
243 | int ubi_more_update_data(struct ubi_device *ubi, int vol_id, | |
244 | const void __user *buf, int count) | |
245 | { | |
246 | uint64_t tmp; | |
247 | struct ubi_volume *vol = ubi->volumes[vol_id]; | |
248 | int lnum, offs, err = 0, len, to_write = count; | |
249 | ||
250 | dbg_msg("write %d of %lld bytes, %lld already passed", | |
251 | count, vol->upd_bytes, vol->upd_received); | |
252 | ||
253 | if (ubi->ro_mode) | |
254 | return -EROFS; | |
255 | ||
256 | tmp = vol->upd_received; | |
257 | offs = do_div(tmp, vol->usable_leb_size); | |
258 | lnum = tmp; | |
259 | ||
260 | if (vol->upd_received + count > vol->upd_bytes) | |
261 | to_write = count = vol->upd_bytes - vol->upd_received; | |
262 | ||
263 | /* | |
264 | * When updating volumes, we accumulate whole logical eraseblock of | |
265 | * data and write it at once. | |
266 | */ | |
267 | if (offs != 0) { | |
268 | /* | |
269 | * This is a write to the middle of the logical eraseblock. We | |
270 | * copy the data to our update buffer and wait for more data or | |
271 | * flush it if the whole eraseblock is written or the update | |
272 | * is finished. | |
273 | */ | |
274 | ||
275 | len = vol->usable_leb_size - offs; | |
276 | if (len > count) | |
277 | len = count; | |
278 | ||
279 | err = copy_from_user(vol->upd_buf + offs, buf, len); | |
280 | if (err) | |
281 | return -EFAULT; | |
282 | ||
283 | if (offs + len == vol->usable_leb_size || | |
284 | vol->upd_received + len == vol->upd_bytes) { | |
285 | int flush_len = offs + len; | |
286 | ||
287 | /* | |
288 | * OK, we gathered either the whole eraseblock or this | |
289 | * is the last chunk, it's time to flush the buffer. | |
290 | */ | |
291 | ubi_assert(flush_len <= vol->usable_leb_size); | |
292 | err = write_leb(ubi, vol_id, lnum, vol->upd_buf, | |
293 | flush_len, vol->upd_ebs); | |
294 | if (err) | |
295 | return err; | |
296 | } | |
297 | ||
298 | vol->upd_received += len; | |
299 | count -= len; | |
300 | buf += len; | |
301 | lnum += 1; | |
302 | } | |
303 | ||
304 | /* | |
305 | * If we've got more to write, let's continue. At this point we know we | |
306 | * are starting from the beginning of an eraseblock. | |
307 | */ | |
308 | while (count) { | |
309 | if (count > vol->usable_leb_size) | |
310 | len = vol->usable_leb_size; | |
311 | else | |
312 | len = count; | |
313 | ||
314 | err = copy_from_user(vol->upd_buf, buf, len); | |
315 | if (err) | |
316 | return -EFAULT; | |
317 | ||
318 | if (len == vol->usable_leb_size || | |
319 | vol->upd_received + len == vol->upd_bytes) { | |
320 | err = write_leb(ubi, vol_id, lnum, vol->upd_buf, len, | |
321 | vol->upd_ebs); | |
322 | if (err) | |
323 | break; | |
324 | } | |
325 | ||
326 | vol->upd_received += len; | |
327 | count -= len; | |
328 | lnum += 1; | |
329 | buf += len; | |
330 | } | |
331 | ||
332 | ubi_assert(vol->upd_received <= vol->upd_bytes); | |
333 | if (vol->upd_received == vol->upd_bytes) { | |
334 | /* The update is finished, clear the update marker */ | |
335 | err = clear_update_marker(ubi, vol_id, vol->upd_bytes); | |
336 | if (err) | |
337 | return err; | |
338 | err = ubi_wl_flush(ubi); | |
339 | if (err == 0) { | |
340 | err = to_write; | |
92ad8f37 | 341 | vfree(vol->upd_buf); |
801c135c AB |
342 | vol->updating = 0; |
343 | } | |
344 | } | |
345 | ||
346 | return err; | |
347 | } |