1 /* 2 * Copyright (c) International Business Machines Corp., 2006 3 * Copyright (c) Nokia Corporation, 2006 4 * 5 * SPDX-License-Identifier: GPL-2.0+ 6 * 7 * Author: Artem Bityutskiy (Битюцкий Артём) 8 * 9 * Jan 2007: Alexander Schmidt, hacked per-volume update. 10 */ 11 12 /* 13 * This file contains implementation of the volume update and atomic LEB change 14 * functionality. 15 * 16 * The update operation is based on the per-volume update marker which is 17 * stored in the volume table. The update marker is set before the update 18 * starts, and removed after the update has been finished. So if the update was 19 * interrupted by an unclean re-boot or due to some other reasons, the update 20 * marker stays on the flash media and UBI finds it when it attaches the MTD 21 * device next time. If the update marker is set for a volume, the volume is 22 * treated as damaged and most I/O operations are prohibited. Only a new update 23 * operation is allowed. 24 * 25 * Note, in general it is possible to implement the update operation as a 26 * transaction with a roll-back capability. 27 */ 28 29 #ifndef __UBOOT__ 30 #include <linux/uaccess.h> 31 #else 32 #include <div64.h> 33 #include <ubi_uboot.h> 34 #endif 35 #include <linux/err.h> 36 #include <linux/math64.h> 37 38 #include "ubi.h" 39 40 /** 41 * set_update_marker - set update marker. 42 * @ubi: UBI device description object 43 * @vol: volume description object 44 * 45 * This function sets the update marker flag for volume @vol. Returns zero 46 * in case of success and a negative error code in case of failure. 47 */ 48 static int set_update_marker(struct ubi_device *ubi, struct ubi_volume *vol) 49 { 50 int err; 51 struct ubi_vtbl_record vtbl_rec; 52 53 dbg_gen("set update marker for volume %d", vol->vol_id); 54 55 if (vol->upd_marker) { 56 ubi_assert(ubi->vtbl[vol->vol_id].upd_marker); 57 dbg_gen("already set"); 58 return 0; 59 } 60 61 vtbl_rec = ubi->vtbl[vol->vol_id]; 62 vtbl_rec.upd_marker = 1; 63 64 mutex_lock(&ubi->device_mutex); 65 err = ubi_change_vtbl_record(ubi, vol->vol_id, &vtbl_rec); 66 vol->upd_marker = 1; 67 mutex_unlock(&ubi->device_mutex); 68 return err; 69 } 70 71 /** 72 * clear_update_marker - clear update marker. 73 * @ubi: UBI device description object 74 * @vol: volume description object 75 * @bytes: new data size in bytes 76 * 77 * This function clears the update marker for volume @vol, sets new volume 78 * data size and clears the "corrupted" flag (static volumes only). Returns 79 * zero in case of success and a negative error code in case of failure. 80 */ 81 static int clear_update_marker(struct ubi_device *ubi, struct ubi_volume *vol, 82 long long bytes) 83 { 84 int err; 85 struct ubi_vtbl_record vtbl_rec; 86 87 dbg_gen("clear update marker for volume %d", vol->vol_id); 88 89 vtbl_rec = ubi->vtbl[vol->vol_id]; 90 ubi_assert(vol->upd_marker && vtbl_rec.upd_marker); 91 vtbl_rec.upd_marker = 0; 92 93 if (vol->vol_type == UBI_STATIC_VOLUME) { 94 vol->corrupted = 0; 95 vol->used_bytes = bytes; 96 vol->used_ebs = div_u64_rem(bytes, vol->usable_leb_size, 97 &vol->last_eb_bytes); 98 if (vol->last_eb_bytes) 99 vol->used_ebs += 1; 100 else 101 vol->last_eb_bytes = vol->usable_leb_size; 102 } 103 104 mutex_lock(&ubi->device_mutex); 105 err = ubi_change_vtbl_record(ubi, vol->vol_id, &vtbl_rec); 106 vol->upd_marker = 0; 107 mutex_unlock(&ubi->device_mutex); 108 return err; 109 } 110 111 /** 112 * ubi_start_update - start volume update. 113 * @ubi: UBI device description object 114 * @vol: volume description object 115 * @bytes: update bytes 116 * 117 * This function starts volume update operation. If @bytes is zero, the volume 118 * is just wiped out. Returns zero in case of success and a negative error code 119 * in case of failure. 120 */ 121 int ubi_start_update(struct ubi_device *ubi, struct ubi_volume *vol, 122 long long bytes) 123 { 124 int i, err; 125 126 dbg_gen("start update of volume %d, %llu bytes", vol->vol_id, bytes); 127 ubi_assert(!vol->updating && !vol->changing_leb); 128 vol->updating = 1; 129 130 err = set_update_marker(ubi, vol); 131 if (err) 132 return err; 133 134 /* Before updating - wipe out the volume */ 135 for (i = 0; i < vol->reserved_pebs; i++) { 136 err = ubi_eba_unmap_leb(ubi, vol, i); 137 if (err) 138 return err; 139 } 140 141 if (bytes == 0) { 142 err = ubi_wl_flush(ubi, UBI_ALL, UBI_ALL); 143 if (err) 144 return err; 145 146 err = clear_update_marker(ubi, vol, 0); 147 if (err) 148 return err; 149 vol->updating = 0; 150 return 0; 151 } 152 153 vol->upd_buf = vmalloc(ubi->leb_size); 154 if (!vol->upd_buf) 155 return -ENOMEM; 156 157 vol->upd_ebs = div_u64(bytes + vol->usable_leb_size - 1, 158 vol->usable_leb_size); 159 vol->upd_bytes = bytes; 160 vol->upd_received = 0; 161 return 0; 162 } 163 164 /** 165 * ubi_start_leb_change - start atomic LEB change. 166 * @ubi: UBI device description object 167 * @vol: volume description object 168 * @req: operation request 169 * 170 * This function starts atomic LEB change operation. Returns zero in case of 171 * success and a negative error code in case of failure. 172 */ 173 int ubi_start_leb_change(struct ubi_device *ubi, struct ubi_volume *vol, 174 const struct ubi_leb_change_req *req) 175 { 176 ubi_assert(!vol->updating && !vol->changing_leb); 177 178 dbg_gen("start changing LEB %d:%d, %u bytes", 179 vol->vol_id, req->lnum, req->bytes); 180 if (req->bytes == 0) 181 return ubi_eba_atomic_leb_change(ubi, vol, req->lnum, NULL, 0); 182 183 vol->upd_bytes = req->bytes; 184 vol->upd_received = 0; 185 vol->changing_leb = 1; 186 vol->ch_lnum = req->lnum; 187 188 vol->upd_buf = vmalloc(req->bytes); 189 if (!vol->upd_buf) 190 return -ENOMEM; 191 192 return 0; 193 } 194 195 /** 196 * write_leb - write update data. 197 * @ubi: UBI device description object 198 * @vol: volume description object 199 * @lnum: logical eraseblock number 200 * @buf: data to write 201 * @len: data size 202 * @used_ebs: how many logical eraseblocks will this volume contain (static 203 * volumes only) 204 * 205 * This function writes update data to corresponding logical eraseblock. In 206 * case of dynamic volume, this function checks if the data contains 0xFF bytes 207 * at the end. If yes, the 0xFF bytes are cut and not written. So if the whole 208 * buffer contains only 0xFF bytes, the LEB is left unmapped. 209 * 210 * The reason why we skip the trailing 0xFF bytes in case of dynamic volume is 211 * that we want to make sure that more data may be appended to the logical 212 * eraseblock in future. Indeed, writing 0xFF bytes may have side effects and 213 * this PEB won't be writable anymore. So if one writes the file-system image 214 * to the UBI volume where 0xFFs mean free space - UBI makes sure this free 215 * space is writable after the update. 216 * 217 * We do not do this for static volumes because they are read-only. But this 218 * also cannot be done because we have to store per-LEB CRC and the correct 219 * data length. 220 * 221 * This function returns zero in case of success and a negative error code in 222 * case of failure. 223 */ 224 static int write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum, 225 void *buf, int len, int used_ebs) 226 { 227 int err; 228 229 if (vol->vol_type == UBI_DYNAMIC_VOLUME) { 230 int l = ALIGN(len, ubi->min_io_size); 231 232 memset(buf + len, 0xFF, l - len); 233 len = ubi_calc_data_len(ubi, buf, l); 234 if (len == 0) { 235 dbg_gen("all %d bytes contain 0xFF - skip", len); 236 return 0; 237 } 238 239 err = ubi_eba_write_leb(ubi, vol, lnum, buf, 0, len); 240 } else { 241 /* 242 * When writing static volume, and this is the last logical 243 * eraseblock, the length (@len) does not have to be aligned to 244 * the minimal flash I/O unit. The 'ubi_eba_write_leb_st()' 245 * function accepts exact (unaligned) length and stores it in 246 * the VID header. And it takes care of proper alignment by 247 * padding the buffer. Here we just make sure the padding will 248 * contain zeros, not random trash. 249 */ 250 memset(buf + len, 0, vol->usable_leb_size - len); 251 err = ubi_eba_write_leb_st(ubi, vol, lnum, buf, len, used_ebs); 252 } 253 254 return err; 255 } 256 257 /** 258 * ubi_more_update_data - write more update data. 259 * @ubi: UBI device description object 260 * @vol: volume description object 261 * @buf: write data (user-space memory buffer) 262 * @count: how much bytes to write 263 * 264 * This function writes more data to the volume which is being updated. It may 265 * be called arbitrary number of times until all the update data arriveis. This 266 * function returns %0 in case of success, number of bytes written during the 267 * last call if the whole volume update has been successfully finished, and a 268 * negative error code in case of failure. 269 */ 270 int ubi_more_update_data(struct ubi_device *ubi, struct ubi_volume *vol, 271 const void __user *buf, int count) 272 { 273 #ifndef __UBOOT__ 274 int lnum, offs, err = 0, len, to_write = count; 275 #else 276 int lnum, err = 0, len, to_write = count; 277 u32 offs; 278 #endif 279 280 dbg_gen("write %d of %lld bytes, %lld already passed", 281 count, vol->upd_bytes, vol->upd_received); 282 283 if (ubi->ro_mode) 284 return -EROFS; 285 286 lnum = div_u64_rem(vol->upd_received, vol->usable_leb_size, &offs); 287 if (vol->upd_received + count > vol->upd_bytes) 288 to_write = count = vol->upd_bytes - vol->upd_received; 289 290 /* 291 * When updating volumes, we accumulate whole logical eraseblock of 292 * data and write it at once. 293 */ 294 if (offs != 0) { 295 /* 296 * This is a write to the middle of the logical eraseblock. We 297 * copy the data to our update buffer and wait for more data or 298 * flush it if the whole eraseblock is written or the update 299 * is finished. 300 */ 301 302 len = vol->usable_leb_size - offs; 303 if (len > count) 304 len = count; 305 306 err = copy_from_user(vol->upd_buf + offs, buf, len); 307 if (err) 308 return -EFAULT; 309 310 if (offs + len == vol->usable_leb_size || 311 vol->upd_received + len == vol->upd_bytes) { 312 int flush_len = offs + len; 313 314 /* 315 * OK, we gathered either the whole eraseblock or this 316 * is the last chunk, it's time to flush the buffer. 317 */ 318 ubi_assert(flush_len <= vol->usable_leb_size); 319 err = write_leb(ubi, vol, lnum, vol->upd_buf, flush_len, 320 vol->upd_ebs); 321 if (err) 322 return err; 323 } 324 325 vol->upd_received += len; 326 count -= len; 327 buf += len; 328 lnum += 1; 329 } 330 331 /* 332 * If we've got more to write, let's continue. At this point we know we 333 * are starting from the beginning of an eraseblock. 334 */ 335 while (count) { 336 if (count > vol->usable_leb_size) 337 len = vol->usable_leb_size; 338 else 339 len = count; 340 341 err = copy_from_user(vol->upd_buf, buf, len); 342 if (err) 343 return -EFAULT; 344 345 if (len == vol->usable_leb_size || 346 vol->upd_received + len == vol->upd_bytes) { 347 err = write_leb(ubi, vol, lnum, vol->upd_buf, 348 len, vol->upd_ebs); 349 if (err) 350 break; 351 } 352 353 vol->upd_received += len; 354 count -= len; 355 lnum += 1; 356 buf += len; 357 } 358 359 ubi_assert(vol->upd_received <= vol->upd_bytes); 360 if (vol->upd_received == vol->upd_bytes) { 361 err = ubi_wl_flush(ubi, UBI_ALL, UBI_ALL); 362 if (err) 363 return err; 364 /* The update is finished, clear the update marker */ 365 err = clear_update_marker(ubi, vol, vol->upd_bytes); 366 if (err) 367 return err; 368 vol->updating = 0; 369 err = to_write; 370 vfree(vol->upd_buf); 371 } 372 373 return err; 374 } 375 376 /** 377 * ubi_more_leb_change_data - accept more data for atomic LEB change. 378 * @ubi: UBI device description object 379 * @vol: volume description object 380 * @buf: write data (user-space memory buffer) 381 * @count: how much bytes to write 382 * 383 * This function accepts more data to the volume which is being under the 384 * "atomic LEB change" operation. It may be called arbitrary number of times 385 * until all data arrives. This function returns %0 in case of success, number 386 * of bytes written during the last call if the whole "atomic LEB change" 387 * operation has been successfully finished, and a negative error code in case 388 * of failure. 389 */ 390 int ubi_more_leb_change_data(struct ubi_device *ubi, struct ubi_volume *vol, 391 const void __user *buf, int count) 392 { 393 int err; 394 395 dbg_gen("write %d of %lld bytes, %lld already passed", 396 count, vol->upd_bytes, vol->upd_received); 397 398 if (ubi->ro_mode) 399 return -EROFS; 400 401 if (vol->upd_received + count > vol->upd_bytes) 402 count = vol->upd_bytes - vol->upd_received; 403 404 err = copy_from_user(vol->upd_buf + vol->upd_received, buf, count); 405 if (err) 406 return -EFAULT; 407 408 vol->upd_received += count; 409 410 if (vol->upd_received == vol->upd_bytes) { 411 int len = ALIGN((int)vol->upd_bytes, ubi->min_io_size); 412 413 memset(vol->upd_buf + vol->upd_bytes, 0xFF, 414 len - vol->upd_bytes); 415 len = ubi_calc_data_len(ubi, vol->upd_buf, len); 416 err = ubi_eba_atomic_leb_change(ubi, vol, vol->ch_lnum, 417 vol->upd_buf, len); 418 if (err) 419 return err; 420 } 421 422 ubi_assert(vol->upd_received <= vol->upd_bytes); 423 if (vol->upd_received == vol->upd_bytes) { 424 vol->changing_leb = 0; 425 err = count; 426 vfree(vol->upd_buf); 427 } 428 429 return err; 430 } 431