2 * Copyright (c) International Business Machines Corp., 2006
3 * Copyright (c) Nokia Corporation, 2006
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.
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.
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
19 * Author: Artem Bityutskiy (Битюцкий Артём)
21 * Jan 2007: Alexander Schmidt, hacked per-volume update.
25 * This file contains implementation of the volume update functionality.
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.
36 * Note, in general it is possible to implement the update operation as a
37 * transaction with a roll-back capability.
40 #include <linux/err.h>
41 #include <asm/uaccess.h>
42 #include <asm/div64.h>
46 * set_update_marker - set update marker.
47 * @ubi: UBI device description object
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.
53 static int set_update_marker(struct ubi_device *ubi, int vol_id)
56 struct ubi_vtbl_record vtbl_rec;
57 struct ubi_volume *vol = ubi->volumes[vol_id];
59 dbg_msg("set update marker for volume %d", vol_id);
61 if (vol->upd_marker) {
62 ubi_assert(ubi->vtbl[vol_id].upd_marker);
63 dbg_msg("already set");
67 memcpy(&vtbl_rec, &ubi->vtbl[vol_id], sizeof(struct ubi_vtbl_record));
68 vtbl_rec.upd_marker = 1;
70 mutex_lock(&ubi->volumes_mutex);
71 err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
72 mutex_unlock(&ubi->volumes_mutex);
78 * clear_update_marker - clear update marker.
79 * @ubi: UBI device description object
81 * @bytes: new data size in bytes
83 * This function clears the update marker for volume @vol_id, sets new volume
84 * data size and clears the "corrupted" flag (static volumes only). Returns
85 * zero in case of success and a negative error code in case of failure.
87 static int clear_update_marker(struct ubi_device *ubi, int vol_id, long long bytes)
91 struct ubi_vtbl_record vtbl_rec;
92 struct ubi_volume *vol = ubi->volumes[vol_id];
94 dbg_msg("clear update marker for volume %d", vol_id);
96 memcpy(&vtbl_rec, &ubi->vtbl[vol_id], sizeof(struct ubi_vtbl_record));
97 ubi_assert(vol->upd_marker && vtbl_rec.upd_marker);
98 vtbl_rec.upd_marker = 0;
100 if (vol->vol_type == UBI_STATIC_VOLUME) {
102 vol->used_bytes = tmp = bytes;
103 vol->last_eb_bytes = do_div(tmp, vol->usable_leb_size);
105 if (vol->last_eb_bytes)
108 vol->last_eb_bytes = vol->usable_leb_size;
111 mutex_lock(&ubi->volumes_mutex);
112 err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
113 mutex_unlock(&ubi->volumes_mutex);
119 * ubi_start_update - start volume update.
120 * @ubi: UBI device description object
122 * @bytes: update bytes
124 * This function starts volume update operation. If @bytes is zero, the volume
125 * is just wiped out. Returns zero in case of success and a negative error code
126 * in case of failure.
128 int ubi_start_update(struct ubi_device *ubi, int vol_id, long long bytes)
132 struct ubi_volume *vol = ubi->volumes[vol_id];
134 dbg_msg("start update of volume %d, %llu bytes", vol_id, bytes);
137 err = set_update_marker(ubi, vol_id);
141 /* Before updating - wipe out the volume */
142 for (i = 0; i < vol->reserved_pebs; i++) {
143 err = ubi_eba_unmap_leb(ubi, vol, i);
149 err = clear_update_marker(ubi, vol_id, 0);
152 err = ubi_wl_flush(ubi);
157 vol->upd_buf = vmalloc(ubi->leb_size);
162 vol->upd_ebs = !!do_div(tmp, vol->usable_leb_size);
164 vol->upd_bytes = bytes;
165 vol->upd_received = 0;
170 * write_leb - write update data.
171 * @ubi: UBI device description object
173 * @lnum: logical eraseblock number
174 * @buf: data to write
176 * @used_ebs: how many logical eraseblocks will this volume contain (static
179 * This function writes update data to corresponding logical eraseblock. In
180 * case of dynamic volume, this function checks if the data contains 0xFF bytes
181 * at the end. If yes, the 0xFF bytes are cut and not written. So if the whole
182 * buffer contains only 0xFF bytes, the LEB is left unmapped.
184 * The reason why we skip the trailing 0xFF bytes in case of dynamic volume is
185 * that we want to make sure that more data may be appended to the logical
186 * eraseblock in future. Indeed, writing 0xFF bytes may have side effects and
187 * this PEB won't be writable anymore. So if one writes the file-system image
188 * to the UBI volume where 0xFFs mean free space - UBI makes sure this free
189 * space is writable after the update.
191 * We do not do this for static volumes because they are read-only. But this
192 * also cannot be done because we have to store per-LEB CRC and the correct
195 * This function returns zero in case of success and a negative error code in
198 static int write_leb(struct ubi_device *ubi, int vol_id, int lnum, void *buf,
199 int len, int used_ebs)
202 struct ubi_volume *vol = ubi->volumes[vol_id];
204 if (vol->vol_type == UBI_DYNAMIC_VOLUME) {
205 l = ALIGN(len, ubi->min_io_size);
206 memset(buf + len, 0xFF, l - len);
208 l = ubi_calc_data_len(ubi, buf, l);
210 dbg_msg("all %d bytes contain 0xFF - skip", len);
214 dbg_msg("skip last %d bytes (0xFF)", len - l);
216 err = ubi_eba_write_leb(ubi, vol, lnum, buf, 0, l, UBI_UNKNOWN);
219 * When writing static volume, and this is the last logical
220 * eraseblock, the length (@len) does not have to be aligned to
221 * the minimal flash I/O unit. The 'ubi_eba_write_leb_st()'
222 * function accepts exact (unaligned) length and stores it in
223 * the VID header. And it takes care of proper alignment by
224 * padding the buffer. Here we just make sure the padding will
225 * contain zeros, not random trash.
227 memset(buf + len, 0, vol->usable_leb_size - len);
228 err = ubi_eba_write_leb_st(ubi, vol, lnum, buf, len,
229 UBI_UNKNOWN, used_ebs);
236 * ubi_more_update_data - write more update data.
237 * @vol: volume description object
238 * @buf: write data (user-space memory buffer)
239 * @count: how much bytes to write
241 * This function writes more data to the volume which is being updated. It may
242 * be called arbitrary number of times until all of the update data arrive.
243 * This function returns %0 in case of success, number of bytes written during
244 * the last call if the whole volume update was successfully finished, and a
245 * negative error code in case of failure.
247 int ubi_more_update_data(struct ubi_device *ubi, int vol_id,
248 const void __user *buf, int count)
251 struct ubi_volume *vol = ubi->volumes[vol_id];
252 int lnum, offs, err = 0, len, to_write = count;
254 dbg_msg("write %d of %lld bytes, %lld already passed",
255 count, vol->upd_bytes, vol->upd_received);
260 tmp = vol->upd_received;
261 offs = do_div(tmp, vol->usable_leb_size);
264 if (vol->upd_received + count > vol->upd_bytes)
265 to_write = count = vol->upd_bytes - vol->upd_received;
268 * When updating volumes, we accumulate whole logical eraseblock of
269 * data and write it at once.
273 * This is a write to the middle of the logical eraseblock. We
274 * copy the data to our update buffer and wait for more data or
275 * flush it if the whole eraseblock is written or the update
279 len = vol->usable_leb_size - offs;
283 err = copy_from_user(vol->upd_buf + offs, buf, len);
287 if (offs + len == vol->usable_leb_size ||
288 vol->upd_received + len == vol->upd_bytes) {
289 int flush_len = offs + len;
292 * OK, we gathered either the whole eraseblock or this
293 * is the last chunk, it's time to flush the buffer.
295 ubi_assert(flush_len <= vol->usable_leb_size);
296 err = write_leb(ubi, vol_id, lnum, vol->upd_buf,
297 flush_len, vol->upd_ebs);
302 vol->upd_received += len;
309 * If we've got more to write, let's continue. At this point we know we
310 * are starting from the beginning of an eraseblock.
313 if (count > vol->usable_leb_size)
314 len = vol->usable_leb_size;
318 err = copy_from_user(vol->upd_buf, buf, len);
322 if (len == vol->usable_leb_size ||
323 vol->upd_received + len == vol->upd_bytes) {
324 err = write_leb(ubi, vol_id, lnum, vol->upd_buf, len,
330 vol->upd_received += len;
336 ubi_assert(vol->upd_received <= vol->upd_bytes);
337 if (vol->upd_received == vol->upd_bytes) {
338 /* The update is finished, clear the update marker */
339 err = clear_update_marker(ubi, vol_id, vol->upd_bytes);
342 err = ubi_wl_flush(ubi);