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 and atomic LEB change 26 * functionality. 27 * 28 * The update operation is based on the per-volume update marker which is 29 * stored in the volume table. The update marker is set before the update 30 * starts, and removed after the update has been finished. So if the update was 31 * interrupted by an unclean re-boot or due to some other reasons, the update 32 * marker stays on the flash media and UBI finds it when it attaches the MTD 33 * device next time. If the update marker is set for a volume, the volume is 34 * treated as damaged and most I/O operations are prohibited. Only a new update 35 * operation is allowed. 36 * 37 * Note, in general it is possible to implement the update operation as a 38 * transaction with a roll-back capability. 39 */ 40 41 #include <linux/err.h> 42 #include <linux/uaccess.h> 43 #include <linux/math64.h> 44 #include "ubi.h" 45 46 /** 47 * set_update_marker - set update marker. 48 * @ubi: UBI device description object 49 * @vol: volume description object 50 * 51 * This function sets the update marker flag for volume @vol. Returns zero 52 * in case of success and a negative error code in case of failure. 53 */ 54 static int set_update_marker(struct ubi_device *ubi, struct ubi_volume *vol) 55 { 56 int err; 57 struct ubi_vtbl_record vtbl_rec; 58 59 dbg_gen("set update marker for volume %d", vol->vol_id); 60 61 if (vol->upd_marker) { 62 ubi_assert(ubi->vtbl[vol->vol_id].upd_marker); 63 dbg_gen("already set"); 64 return 0; 65 } 66 67 vtbl_rec = ubi->vtbl[vol->vol_id]; 68 vtbl_rec.upd_marker = 1; 69 70 mutex_lock(&ubi->device_mutex); 71 err = ubi_change_vtbl_record(ubi, vol->vol_id, &vtbl_rec); 72 vol->upd_marker = 1; 73 mutex_unlock(&ubi->device_mutex); 74 return err; 75 } 76 77 /** 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 82 * 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. 86 */ 87 static int clear_update_marker(struct ubi_device *ubi, struct ubi_volume *vol, 88 long long bytes) 89 { 90 int err; 91 struct ubi_vtbl_record vtbl_rec; 92 93 dbg_gen("clear update marker for volume %d", vol->vol_id); 94 95 vtbl_rec = ubi->vtbl[vol->vol_id]; 96 ubi_assert(vol->upd_marker && vtbl_rec.upd_marker); 97 vtbl_rec.upd_marker = 0; 98 99 if (vol->vol_type == UBI_STATIC_VOLUME) { 100 vol->corrupted = 0; 101 vol->used_bytes = bytes; 102 vol->used_ebs = div_u64_rem(bytes, vol->usable_leb_size, 103 &vol->last_eb_bytes); 104 if (vol->last_eb_bytes) 105 vol->used_ebs += 1; 106 else 107 vol->last_eb_bytes = vol->usable_leb_size; 108 } 109 110 mutex_lock(&ubi->device_mutex); 111 err = ubi_change_vtbl_record(ubi, vol->vol_id, &vtbl_rec); 112 vol->upd_marker = 0; 113 mutex_unlock(&ubi->device_mutex); 114 return err; 115 } 116 117 /** 118 * ubi_start_update - start volume update. 119 * @ubi: UBI device description object 120 * @vol: volume description object 121 * @bytes: update bytes 122 * 123 * This function starts volume update operation. If @bytes is zero, the volume 124 * is just wiped out. Returns zero in case of success and a negative error code 125 * in case of failure. 126 */ 127 int ubi_start_update(struct ubi_device *ubi, struct ubi_volume *vol, 128 long long bytes) 129 { 130 int i, err; 131 132 dbg_gen("start update of volume %d, %llu bytes", vol->vol_id, bytes); 133 ubi_assert(!vol->updating && !vol->changing_leb); 134 vol->updating = 1; 135 136 err = set_update_marker(ubi, vol); 137 if (err) 138 return err; 139 140 /* Before updating - wipe out the volume */ 141 for (i = 0; i < vol->reserved_pebs; i++) { 142 err = ubi_eba_unmap_leb(ubi, vol, i); 143 if (err) 144 return err; 145 } 146 147 if (bytes == 0) { 148 err = ubi_wl_flush(ubi, UBI_ALL, UBI_ALL); 149 if (err) 150 return err; 151 152 err = clear_update_marker(ubi, vol, 0); 153 if (err) 154 return err; 155 vol->updating = 0; 156 return 0; 157 } 158 159 vol->upd_buf = vmalloc(ubi->leb_size); 160 if (!vol->upd_buf) 161 return -ENOMEM; 162 163 vol->upd_ebs = div_u64(bytes + vol->usable_leb_size - 1, 164 vol->usable_leb_size); 165 vol->upd_bytes = bytes; 166 vol->upd_received = 0; 167 return 0; 168 } 169 170 /** 171 * ubi_start_leb_change - start atomic LEB change. 172 * @ubi: UBI device description object 173 * @vol: volume description object 174 * @req: operation request 175 * 176 * This function starts atomic LEB change operation. Returns zero in case of 177 * success and a negative error code in case of failure. 178 */ 179 int ubi_start_leb_change(struct ubi_device *ubi, struct ubi_volume *vol, 180 const struct ubi_leb_change_req *req) 181 { 182 ubi_assert(!vol->updating && !vol->changing_leb); 183 184 dbg_gen("start changing LEB %d:%d, %u bytes", 185 vol->vol_id, req->lnum, req->bytes); 186 if (req->bytes == 0) 187 return ubi_eba_atomic_leb_change(ubi, vol, req->lnum, NULL, 0); 188 189 vol->upd_bytes = req->bytes; 190 vol->upd_received = 0; 191 vol->changing_leb = 1; 192 vol->ch_lnum = req->lnum; 193 194 vol->upd_buf = vmalloc(req->bytes); 195 if (!vol->upd_buf) 196 return -ENOMEM; 197 198 return 0; 199 } 200 201 /** 202 * write_leb - write update data. 203 * @ubi: UBI device description object 204 * @vol: volume description object 205 * @lnum: logical eraseblock number 206 * @buf: data to write 207 * @len: data size 208 * @used_ebs: how many logical eraseblocks will this volume contain (static 209 * volumes only) 210 * 211 * This function writes update data to corresponding logical eraseblock. In 212 * case of dynamic volume, this function checks if the data contains 0xFF bytes 213 * at the end. If yes, the 0xFF bytes are cut and not written. So if the whole 214 * buffer contains only 0xFF bytes, the LEB is left unmapped. 215 * 216 * The reason why we skip the trailing 0xFF bytes in case of dynamic volume is 217 * that we want to make sure that more data may be appended to the logical 218 * eraseblock in future. Indeed, writing 0xFF bytes may have side effects and 219 * this PEB won't be writable anymore. So if one writes the file-system image 220 * to the UBI volume where 0xFFs mean free space - UBI makes sure this free 221 * space is writable after the update. 222 * 223 * We do not do this for static volumes because they are read-only. But this 224 * also cannot be done because we have to store per-LEB CRC and the correct 225 * data length. 226 * 227 * This function returns zero in case of success and a negative error code in 228 * case of failure. 229 */ 230 static int write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum, 231 void *buf, int len, int used_ebs) 232 { 233 int err; 234 235 if (vol->vol_type == UBI_DYNAMIC_VOLUME) { 236 int l = ALIGN(len, ubi->min_io_size); 237 238 memset(buf + len, 0xFF, l - len); 239 len = ubi_calc_data_len(ubi, buf, l); 240 if (len == 0) { 241 dbg_gen("all %d bytes contain 0xFF - skip", len); 242 return 0; 243 } 244 245 err = ubi_eba_write_leb(ubi, vol, lnum, buf, 0, len); 246 } else { 247 /* 248 * When writing static volume, and this is the last logical 249 * eraseblock, the length (@len) does not have to be aligned to 250 * the minimal flash I/O unit. The 'ubi_eba_write_leb_st()' 251 * function accepts exact (unaligned) length and stores it in 252 * the VID header. And it takes care of proper alignment by 253 * padding the buffer. Here we just make sure the padding will 254 * contain zeros, not random trash. 255 */ 256 memset(buf + len, 0, vol->usable_leb_size - len); 257 err = ubi_eba_write_leb_st(ubi, vol, lnum, buf, len, used_ebs); 258 } 259 260 return err; 261 } 262 263 /** 264 * ubi_more_update_data - write more update data. 265 * @ubi: UBI device description object 266 * @vol: volume description object 267 * @buf: write data (user-space memory buffer) 268 * @count: how much bytes to write 269 * 270 * This function writes more data to the volume which is being updated. It may 271 * be called arbitrary number of times until all the update data arriveis. This 272 * function returns %0 in case of success, number of bytes written during the 273 * last call if the whole volume update has been successfully finished, and a 274 * negative error code in case of failure. 275 */ 276 int ubi_more_update_data(struct ubi_device *ubi, struct ubi_volume *vol, 277 const void __user *buf, int count) 278 { 279 int lnum, offs, err = 0, len, to_write = count; 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 */ 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