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
48 * @vol: volume description object
50 * This function sets the update marker flag for volume @vol. 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, struct ubi_volume *vol)
56 struct ubi_vtbl_record vtbl_rec;
58 dbg_msg("set update marker for volume %d", vol->vol_id);
60 if (vol->upd_marker) {
61 ubi_assert(ubi->vtbl[vol->vol_id].upd_marker);
62 dbg_msg("already set");
66 memcpy(&vtbl_rec, &ubi->vtbl[vol->vol_id],
67 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->vol_id, &vtbl_rec);
72 mutex_unlock(&ubi->volumes_mutex);
78 * clear_update_marker - clear update marker.
79 * @ubi: UBI device description object
80 * @vol: volume description object
81 * @bytes: new data size in bytes
83 * This function clears the update marker for volume @vol, 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, struct ubi_volume *vol,
92 struct ubi_vtbl_record vtbl_rec;
94 dbg_msg("clear update marker for volume %d", vol->vol_id);
96 memcpy(&vtbl_rec, &ubi->vtbl[vol->vol_id],
97 sizeof(struct ubi_vtbl_record));
98 ubi_assert(vol->upd_marker && vtbl_rec.upd_marker);
99 vtbl_rec.upd_marker = 0;
101 if (vol->vol_type == UBI_STATIC_VOLUME) {
103 vol->used_bytes = tmp = bytes;
104 vol->last_eb_bytes = do_div(tmp, vol->usable_leb_size);
106 if (vol->last_eb_bytes)
109 vol->last_eb_bytes = vol->usable_leb_size;
112 mutex_lock(&ubi->volumes_mutex);
113 err = ubi_change_vtbl_record(ubi, vol->vol_id, &vtbl_rec);
114 mutex_unlock(&ubi->volumes_mutex);
120 * ubi_start_update - start volume update.
121 * @ubi: UBI device description object
122 * @vol: volume description object
123 * @bytes: update bytes
125 * This function starts volume update operation. If @bytes is zero, the volume
126 * is just wiped out. Returns zero in case of success and a negative error code
127 * in case of failure.
129 int ubi_start_update(struct ubi_device *ubi, struct ubi_volume *vol,
135 dbg_msg("start update of volume %d, %llu bytes", vol->vol_id, bytes);
138 err = set_update_marker(ubi, vol);
142 /* Before updating - wipe out the volume */
143 for (i = 0; i < vol->reserved_pebs; i++) {
144 err = ubi_eba_unmap_leb(ubi, vol, i);
150 err = clear_update_marker(ubi, vol, 0);
153 err = ubi_wl_flush(ubi);
158 vol->upd_buf = vmalloc(ubi->leb_size);
163 vol->upd_ebs = !!do_div(tmp, vol->usable_leb_size);
165 vol->upd_bytes = bytes;
166 vol->upd_received = 0;
171 * write_leb - write update data.
172 * @ubi: UBI device description object
173 * @vol: volume description object
174 * @lnum: logical eraseblock number
175 * @buf: data to write
177 * @used_ebs: how many logical eraseblocks will this volume contain (static
180 * This function writes update data to corresponding logical eraseblock. In
181 * case of dynamic volume, this function checks if the data contains 0xFF bytes
182 * at the end. If yes, the 0xFF bytes are cut and not written. So if the whole
183 * buffer contains only 0xFF bytes, the LEB is left unmapped.
185 * The reason why we skip the trailing 0xFF bytes in case of dynamic volume is
186 * that we want to make sure that more data may be appended to the logical
187 * eraseblock in future. Indeed, writing 0xFF bytes may have side effects and
188 * this PEB won't be writable anymore. So if one writes the file-system image
189 * to the UBI volume where 0xFFs mean free space - UBI makes sure this free
190 * space is writable after the update.
192 * We do not do this for static volumes because they are read-only. But this
193 * also cannot be done because we have to store per-LEB CRC and the correct
196 * This function returns zero in case of success and a negative error code in
199 static int write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
200 void *buf, int len, int used_ebs)
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, struct ubi_volume *vol,
248 const void __user *buf, int count)
251 int lnum, offs, err = 0, len, to_write = count;
253 dbg_msg("write %d of %lld bytes, %lld already passed",
254 count, vol->upd_bytes, vol->upd_received);
259 tmp = vol->upd_received;
260 offs = do_div(tmp, vol->usable_leb_size);
263 if (vol->upd_received + count > vol->upd_bytes)
264 to_write = count = vol->upd_bytes - vol->upd_received;
267 * When updating volumes, we accumulate whole logical eraseblock of
268 * data and write it at once.
272 * This is a write to the middle of the logical eraseblock. We
273 * copy the data to our update buffer and wait for more data or
274 * flush it if the whole eraseblock is written or the update
278 len = vol->usable_leb_size - offs;
282 err = copy_from_user(vol->upd_buf + offs, buf, len);
286 if (offs + len == vol->usable_leb_size ||
287 vol->upd_received + len == vol->upd_bytes) {
288 int flush_len = offs + len;
291 * OK, we gathered either the whole eraseblock or this
292 * is the last chunk, it's time to flush the buffer.
294 ubi_assert(flush_len <= vol->usable_leb_size);
295 err = write_leb(ubi, vol, lnum, vol->upd_buf, flush_len,
301 vol->upd_received += len;
308 * If we've got more to write, let's continue. At this point we know we
309 * are starting from the beginning of an eraseblock.
312 if (count > vol->usable_leb_size)
313 len = vol->usable_leb_size;
317 err = copy_from_user(vol->upd_buf, buf, len);
321 if (len == vol->usable_leb_size ||
322 vol->upd_received + len == vol->upd_bytes) {
323 err = write_leb(ubi, vol, lnum, vol->upd_buf,
329 vol->upd_received += len;
335 ubi_assert(vol->upd_received <= vol->upd_bytes);
336 if (vol->upd_received == vol->upd_bytes) {
337 /* The update is finished, clear the update marker */
338 err = clear_update_marker(ubi, vol, vol->upd_bytes);
341 err = ubi_wl_flush(ubi);