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 vol->upd_buf = vmalloc(ubi->leb_size); 137 if (!vol->upd_buf) 138 return -ENOMEM; 139 140 err = set_update_marker(ubi, vol); 141 if (err) 142 return err; 143 144 /* Before updating - wipe out the volume */ 145 for (i = 0; i < vol->reserved_pebs; i++) { 146 err = ubi_eba_unmap_leb(ubi, vol, i); 147 if (err) 148 return err; 149 } 150 151 if (bytes == 0) { 152 err = ubi_wl_flush(ubi, UBI_ALL, UBI_ALL); 153 if (err) 154 return err; 155 156 err = clear_update_marker(ubi, vol, 0); 157 if (err) 158 return err; 159 160 vfree(vol->upd_buf); 161 vol->updating = 0; 162 return 0; 163 } 164 165 vol->upd_ebs = div_u64(bytes + vol->usable_leb_size - 1, 166 vol->usable_leb_size); 167 vol->upd_bytes = bytes; 168 vol->upd_received = 0; 169 return 0; 170 } 171 172 /** 173 * ubi_start_leb_change - start atomic LEB change. 174 * @ubi: UBI device description object 175 * @vol: volume description object 176 * @req: operation request 177 * 178 * This function starts atomic LEB change operation. Returns zero in case of 179 * success and a negative error code in case of failure. 180 */ 181 int ubi_start_leb_change(struct ubi_device *ubi, struct ubi_volume *vol, 182 const struct ubi_leb_change_req *req) 183 { 184 ubi_assert(!vol->updating && !vol->changing_leb); 185 186 dbg_gen("start changing LEB %d:%d, %u bytes", 187 vol->vol_id, req->lnum, req->bytes); 188 if (req->bytes == 0) 189 return ubi_eba_atomic_leb_change(ubi, vol, req->lnum, NULL, 0); 190 191 vol->upd_bytes = req->bytes; 192 vol->upd_received = 0; 193 vol->changing_leb = 1; 194 vol->ch_lnum = req->lnum; 195 196 vol->upd_buf = vmalloc(req->bytes); 197 if (!vol->upd_buf) 198 return -ENOMEM; 199 200 return 0; 201 } 202 203 /** 204 * write_leb - write update data. 205 * @ubi: UBI device description object 206 * @vol: volume description object 207 * @lnum: logical eraseblock number 208 * @buf: data to write 209 * @len: data size 210 * @used_ebs: how many logical eraseblocks will this volume contain (static 211 * volumes only) 212 * 213 * This function writes update data to corresponding logical eraseblock. In 214 * case of dynamic volume, this function checks if the data contains 0xFF bytes 215 * at the end. If yes, the 0xFF bytes are cut and not written. So if the whole 216 * buffer contains only 0xFF bytes, the LEB is left unmapped. 217 * 218 * The reason why we skip the trailing 0xFF bytes in case of dynamic volume is 219 * that we want to make sure that more data may be appended to the logical 220 * eraseblock in future. Indeed, writing 0xFF bytes may have side effects and 221 * this PEB won't be writable anymore. So if one writes the file-system image 222 * to the UBI volume where 0xFFs mean free space - UBI makes sure this free 223 * space is writable after the update. 224 * 225 * We do not do this for static volumes because they are read-only. But this 226 * also cannot be done because we have to store per-LEB CRC and the correct 227 * data length. 228 * 229 * This function returns zero in case of success and a negative error code in 230 * case of failure. 231 */ 232 static int write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum, 233 void *buf, int len, int used_ebs) 234 { 235 int err; 236 237 if (vol->vol_type == UBI_DYNAMIC_VOLUME) { 238 int l = ALIGN(len, ubi->min_io_size); 239 240 memset(buf + len, 0xFF, l - len); 241 len = ubi_calc_data_len(ubi, buf, l); 242 if (len == 0) { 243 dbg_gen("all %d bytes contain 0xFF - skip", len); 244 return 0; 245 } 246 247 err = ubi_eba_write_leb(ubi, vol, lnum, buf, 0, len); 248 } else { 249 /* 250 * When writing static volume, and this is the last logical 251 * eraseblock, the length (@len) does not have to be aligned to 252 * the minimal flash I/O unit. The 'ubi_eba_write_leb_st()' 253 * function accepts exact (unaligned) length and stores it in 254 * the VID header. And it takes care of proper alignment by 255 * padding the buffer. Here we just make sure the padding will 256 * contain zeros, not random trash. 257 */ 258 memset(buf + len, 0, vol->usable_leb_size - len); 259 err = ubi_eba_write_leb_st(ubi, vol, lnum, buf, len, used_ebs); 260 } 261 262 return err; 263 } 264 265 /** 266 * ubi_more_update_data - write more update data. 267 * @ubi: UBI device description object 268 * @vol: volume description object 269 * @buf: write data (user-space memory buffer) 270 * @count: how much bytes to write 271 * 272 * This function writes more data to the volume which is being updated. It may 273 * be called arbitrary number of times until all the update data arriveis. This 274 * function returns %0 in case of success, number of bytes written during the 275 * last call if the whole volume update has been successfully finished, and a 276 * negative error code in case of failure. 277 */ 278 int ubi_more_update_data(struct ubi_device *ubi, struct ubi_volume *vol, 279 const void __user *buf, int count) 280 { 281 int lnum, offs, err = 0, len, to_write = count; 282 283 dbg_gen("write %d of %lld bytes, %lld already passed", 284 count, vol->upd_bytes, vol->upd_received); 285 286 if (ubi->ro_mode) 287 return -EROFS; 288 289 lnum = div_u64_rem(vol->upd_received, vol->usable_leb_size, &offs); 290 if (vol->upd_received + count > vol->upd_bytes) 291 to_write = count = vol->upd_bytes - vol->upd_received; 292 293 /* 294 * When updating volumes, we accumulate whole logical eraseblock of 295 * data and write it at once. 296 */ 297 if (offs != 0) { 298 /* 299 * This is a write to the middle of the logical eraseblock. We 300 * copy the data to our update buffer and wait for more data or 301 * flush it if the whole eraseblock is written or the update 302 * is finished. 303 */ 304 305 len = vol->usable_leb_size - offs; 306 if (len > count) 307 len = count; 308 309 err = copy_from_user(vol->upd_buf + offs, buf, len); 310 if (err) 311 return -EFAULT; 312 313 if (offs + len == vol->usable_leb_size || 314 vol->upd_received + len == vol->upd_bytes) { 315 int flush_len = offs + len; 316 317 /* 318 * OK, we gathered either the whole eraseblock or this 319 * is the last chunk, it's time to flush the buffer. 320 */ 321 ubi_assert(flush_len <= vol->usable_leb_size); 322 err = write_leb(ubi, vol, lnum, vol->upd_buf, flush_len, 323 vol->upd_ebs); 324 if (err) 325 return err; 326 } 327 328 vol->upd_received += len; 329 count -= len; 330 buf += len; 331 lnum += 1; 332 } 333 334 /* 335 * If we've got more to write, let's continue. At this point we know we 336 * are starting from the beginning of an eraseblock. 337 */ 338 while (count) { 339 if (count > vol->usable_leb_size) 340 len = vol->usable_leb_size; 341 else 342 len = count; 343 344 err = copy_from_user(vol->upd_buf, buf, len); 345 if (err) 346 return -EFAULT; 347 348 if (len == vol->usable_leb_size || 349 vol->upd_received + len == vol->upd_bytes) { 350 err = write_leb(ubi, vol, lnum, vol->upd_buf, 351 len, vol->upd_ebs); 352 if (err) 353 break; 354 } 355 356 vol->upd_received += len; 357 count -= len; 358 lnum += 1; 359 buf += len; 360 } 361 362 ubi_assert(vol->upd_received <= vol->upd_bytes); 363 if (vol->upd_received == vol->upd_bytes) { 364 err = ubi_wl_flush(ubi, UBI_ALL, UBI_ALL); 365 if (err) 366 return err; 367 /* The update is finished, clear the update marker */ 368 err = clear_update_marker(ubi, vol, vol->upd_bytes); 369 if (err) 370 return err; 371 vol->updating = 0; 372 err = to_write; 373 vfree(vol->upd_buf); 374 } 375 376 return err; 377 } 378 379 /** 380 * ubi_more_leb_change_data - accept more data for atomic LEB change. 381 * @ubi: UBI device description object 382 * @vol: volume description object 383 * @buf: write data (user-space memory buffer) 384 * @count: how much bytes to write 385 * 386 * This function accepts more data to the volume which is being under the 387 * "atomic LEB change" operation. It may be called arbitrary number of times 388 * until all data arrives. This function returns %0 in case of success, number 389 * of bytes written during the last call if the whole "atomic LEB change" 390 * operation has been successfully finished, and a negative error code in case 391 * of failure. 392 */ 393 int ubi_more_leb_change_data(struct ubi_device *ubi, struct ubi_volume *vol, 394 const void __user *buf, int count) 395 { 396 int err; 397 398 dbg_gen("write %d of %lld bytes, %lld already passed", 399 count, vol->upd_bytes, vol->upd_received); 400 401 if (ubi->ro_mode) 402 return -EROFS; 403 404 if (vol->upd_received + count > vol->upd_bytes) 405 count = vol->upd_bytes - vol->upd_received; 406 407 err = copy_from_user(vol->upd_buf + vol->upd_received, buf, count); 408 if (err) 409 return -EFAULT; 410 411 vol->upd_received += count; 412 413 if (vol->upd_received == vol->upd_bytes) { 414 int len = ALIGN((int)vol->upd_bytes, ubi->min_io_size); 415 416 memset(vol->upd_buf + vol->upd_bytes, 0xFF, 417 len - vol->upd_bytes); 418 len = ubi_calc_data_len(ubi, vol->upd_buf, len); 419 err = ubi_eba_atomic_leb_change(ubi, vol, vol->ch_lnum, 420 vol->upd_buf, len); 421 if (err) 422 return err; 423 } 424 425 ubi_assert(vol->upd_received <= vol->upd_bytes); 426 if (vol->upd_received == vol->upd_bytes) { 427 vol->changing_leb = 0; 428 err = count; 429 vfree(vol->upd_buf); 430 } 431 432 return err; 433 } 434