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 vol->upd_buf = vmalloc(ubi->leb_size); 131 if (!vol->upd_buf) 132 return -ENOMEM; 133 134 err = set_update_marker(ubi, vol); 135 if (err) 136 return err; 137 138 /* Before updating - wipe out the volume */ 139 for (i = 0; i < vol->reserved_pebs; i++) { 140 err = ubi_eba_unmap_leb(ubi, vol, i); 141 if (err) 142 return err; 143 } 144 145 if (bytes == 0) { 146 err = ubi_wl_flush(ubi, UBI_ALL, UBI_ALL); 147 if (err) 148 return err; 149 150 err = clear_update_marker(ubi, vol, 0); 151 if (err) 152 return err; 153 154 vfree(vol->upd_buf); 155 vol->updating = 0; 156 return 0; 157 } 158 159 vol->upd_ebs = div_u64(bytes + vol->usable_leb_size - 1, 160 vol->usable_leb_size); 161 vol->upd_bytes = bytes; 162 vol->upd_received = 0; 163 return 0; 164 } 165 166 /** 167 * ubi_start_leb_change - start atomic LEB change. 168 * @ubi: UBI device description object 169 * @vol: volume description object 170 * @req: operation request 171 * 172 * This function starts atomic LEB change operation. Returns zero in case of 173 * success and a negative error code in case of failure. 174 */ 175 int ubi_start_leb_change(struct ubi_device *ubi, struct ubi_volume *vol, 176 const struct ubi_leb_change_req *req) 177 { 178 ubi_assert(!vol->updating && !vol->changing_leb); 179 180 dbg_gen("start changing LEB %d:%d, %u bytes", 181 vol->vol_id, req->lnum, req->bytes); 182 if (req->bytes == 0) 183 return ubi_eba_atomic_leb_change(ubi, vol, req->lnum, NULL, 0); 184 185 vol->upd_bytes = req->bytes; 186 vol->upd_received = 0; 187 vol->changing_leb = 1; 188 vol->ch_lnum = req->lnum; 189 190 vol->upd_buf = vmalloc(req->bytes); 191 if (!vol->upd_buf) 192 return -ENOMEM; 193 194 return 0; 195 } 196 197 /** 198 * write_leb - write update data. 199 * @ubi: UBI device description object 200 * @vol: volume description object 201 * @lnum: logical eraseblock number 202 * @buf: data to write 203 * @len: data size 204 * @used_ebs: how many logical eraseblocks will this volume contain (static 205 * volumes only) 206 * 207 * This function writes update data to corresponding logical eraseblock. In 208 * case of dynamic volume, this function checks if the data contains 0xFF bytes 209 * at the end. If yes, the 0xFF bytes are cut and not written. So if the whole 210 * buffer contains only 0xFF bytes, the LEB is left unmapped. 211 * 212 * The reason why we skip the trailing 0xFF bytes in case of dynamic volume is 213 * that we want to make sure that more data may be appended to the logical 214 * eraseblock in future. Indeed, writing 0xFF bytes may have side effects and 215 * this PEB won't be writable anymore. So if one writes the file-system image 216 * to the UBI volume where 0xFFs mean free space - UBI makes sure this free 217 * space is writable after the update. 218 * 219 * We do not do this for static volumes because they are read-only. But this 220 * also cannot be done because we have to store per-LEB CRC and the correct 221 * data length. 222 * 223 * This function returns zero in case of success and a negative error code in 224 * case of failure. 225 */ 226 static int write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum, 227 void *buf, int len, int used_ebs) 228 { 229 int err; 230 231 if (vol->vol_type == UBI_DYNAMIC_VOLUME) { 232 int l = ALIGN(len, ubi->min_io_size); 233 234 memset(buf + len, 0xFF, l - len); 235 len = ubi_calc_data_len(ubi, buf, l); 236 if (len == 0) { 237 dbg_gen("all %d bytes contain 0xFF - skip", len); 238 return 0; 239 } 240 241 err = ubi_eba_write_leb(ubi, vol, lnum, buf, 0, len); 242 } else { 243 /* 244 * When writing static volume, and this is the last logical 245 * eraseblock, the length (@len) does not have to be aligned to 246 * the minimal flash I/O unit. The 'ubi_eba_write_leb_st()' 247 * function accepts exact (unaligned) length and stores it in 248 * the VID header. And it takes care of proper alignment by 249 * padding the buffer. Here we just make sure the padding will 250 * contain zeros, not random trash. 251 */ 252 memset(buf + len, 0, vol->usable_leb_size - len); 253 err = ubi_eba_write_leb_st(ubi, vol, lnum, buf, len, used_ebs); 254 } 255 256 return err; 257 } 258 259 /** 260 * ubi_more_update_data - write more update data. 261 * @ubi: UBI device description object 262 * @vol: volume description object 263 * @buf: write data (user-space memory buffer) 264 * @count: how much bytes to write 265 * 266 * This function writes more data to the volume which is being updated. It may 267 * be called arbitrary number of times until all the update data arriveis. This 268 * function returns %0 in case of success, number of bytes written during the 269 * last call if the whole volume update has been successfully finished, and a 270 * negative error code in case of failure. 271 */ 272 int ubi_more_update_data(struct ubi_device *ubi, struct ubi_volume *vol, 273 const void __user *buf, int count) 274 { 275 #ifndef __UBOOT__ 276 int lnum, offs, err = 0, len, to_write = count; 277 #else 278 int lnum, err = 0, len, to_write = count; 279 u32 offs; 280 #endif 281 282 dbg_gen("write %d of %lld bytes, %lld already passed", 283 count, vol->upd_bytes, vol->upd_received); 284 285 if (ubi->ro_mode) 286 return -EROFS; 287 288 lnum = div_u64_rem(vol->upd_received, vol->usable_leb_size, &offs); 289 if (vol->upd_received + count > vol->upd_bytes) 290 to_write = count = vol->upd_bytes - vol->upd_received; 291 292 /* 293 * When updating volumes, we accumulate whole logical eraseblock of 294 * data and write it at once. 295 */ 296 if (offs != 0) { 297 /* 298 * This is a write to the middle of the logical eraseblock. We 299 * copy the data to our update buffer and wait for more data or 300 * flush it if the whole eraseblock is written or the update 301 * is finished. 302 */ 303 304 len = vol->usable_leb_size - offs; 305 if (len > count) 306 len = count; 307 308 err = copy_from_user(vol->upd_buf + offs, buf, len); 309 if (err) 310 return -EFAULT; 311 312 if (offs + len == vol->usable_leb_size || 313 vol->upd_received + len == vol->upd_bytes) { 314 int flush_len = offs + len; 315 316 /* 317 * OK, we gathered either the whole eraseblock or this 318 * is the last chunk, it's time to flush the buffer. 319 */ 320 ubi_assert(flush_len <= vol->usable_leb_size); 321 err = write_leb(ubi, vol, lnum, vol->upd_buf, flush_len, 322 vol->upd_ebs); 323 if (err) 324 return err; 325 } 326 327 vol->upd_received += len; 328 count -= len; 329 buf += len; 330 lnum += 1; 331 } 332 333 /* 334 * If we've got more to write, let's continue. At this point we know we 335 * are starting from the beginning of an eraseblock. 336 */ 337 while (count) { 338 if (count > vol->usable_leb_size) 339 len = vol->usable_leb_size; 340 else 341 len = count; 342 343 err = copy_from_user(vol->upd_buf, buf, len); 344 if (err) 345 return -EFAULT; 346 347 if (len == vol->usable_leb_size || 348 vol->upd_received + len == vol->upd_bytes) { 349 err = write_leb(ubi, vol, lnum, vol->upd_buf, 350 len, vol->upd_ebs); 351 if (err) 352 break; 353 } 354 355 vol->upd_received += len; 356 count -= len; 357 lnum += 1; 358 buf += len; 359 } 360 361 ubi_assert(vol->upd_received <= vol->upd_bytes); 362 if (vol->upd_received == vol->upd_bytes) { 363 err = ubi_wl_flush(ubi, UBI_ALL, UBI_ALL); 364 if (err) 365 return err; 366 /* The update is finished, clear the update marker */ 367 err = clear_update_marker(ubi, vol, vol->upd_bytes); 368 if (err) 369 return err; 370 vol->updating = 0; 371 err = to_write; 372 vfree(vol->upd_buf); 373 } 374 375 return err; 376 } 377 378 /** 379 * ubi_more_leb_change_data - accept more data for atomic LEB change. 380 * @ubi: UBI device description object 381 * @vol: volume description object 382 * @buf: write data (user-space memory buffer) 383 * @count: how much bytes to write 384 * 385 * This function accepts more data to the volume which is being under the 386 * "atomic LEB change" operation. It may be called arbitrary number of times 387 * until all data arrives. This function returns %0 in case of success, number 388 * of bytes written during the last call if the whole "atomic LEB change" 389 * operation has been successfully finished, and a negative error code in case 390 * of failure. 391 */ 392 int ubi_more_leb_change_data(struct ubi_device *ubi, struct ubi_volume *vol, 393 const void __user *buf, int count) 394 { 395 int err; 396 397 dbg_gen("write %d of %lld bytes, %lld already passed", 398 count, vol->upd_bytes, vol->upd_received); 399 400 if (ubi->ro_mode) 401 return -EROFS; 402 403 if (vol->upd_received + count > vol->upd_bytes) 404 count = vol->upd_bytes - vol->upd_received; 405 406 err = copy_from_user(vol->upd_buf + vol->upd_received, buf, count); 407 if (err) 408 return -EFAULT; 409 410 vol->upd_received += count; 411 412 if (vol->upd_received == vol->upd_bytes) { 413 int len = ALIGN((int)vol->upd_bytes, ubi->min_io_size); 414 415 memset(vol->upd_buf + vol->upd_bytes, 0xFF, 416 len - vol->upd_bytes); 417 len = ubi_calc_data_len(ubi, vol->upd_buf, len); 418 err = ubi_eba_atomic_leb_change(ubi, vol, vol->ch_lnum, 419 vol->upd_buf, len); 420 if (err) 421 return err; 422 } 423 424 ubi_assert(vol->upd_received <= vol->upd_bytes); 425 if (vol->upd_received == vol->upd_bytes) { 426 vol->changing_leb = 0; 427 err = count; 428 vfree(vol->upd_buf); 429 } 430 431 return err; 432 } 433