1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Copyright (c) International Business Machines Corp., 2006 4 * Copyright (c) Nokia Corporation, 2006 5 * 6 * Author: Artem Bityutskiy (Битюцкий Артём) 7 * 8 * Jan 2007: Alexander Schmidt, hacked per-volume update. 9 */ 10 11 /* 12 * This file contains implementation of the volume update and atomic LEB change 13 * functionality. 14 * 15 * The update operation is based on the per-volume update marker which is 16 * stored in the volume table. The update marker is set before the update 17 * starts, and removed after the update has been finished. So if the update was 18 * interrupted by an unclean re-boot or due to some other reasons, the update 19 * marker stays on the flash media and UBI finds it when it attaches the MTD 20 * device next time. If the update marker is set for a volume, the volume is 21 * treated as damaged and most I/O operations are prohibited. Only a new update 22 * operation is allowed. 23 * 24 * Note, in general it is possible to implement the update operation as a 25 * transaction with a roll-back capability. 26 */ 27 28 #ifndef __UBOOT__ 29 #include <linux/uaccess.h> 30 #else 31 #include <div64.h> 32 #include <ubi_uboot.h> 33 #endif 34 #include <linux/err.h> 35 #include <linux/math64.h> 36 37 #include "ubi.h" 38 39 /** 40 * set_update_marker - set update marker. 41 * @ubi: UBI device description object 42 * @vol: volume description object 43 * 44 * This function sets the update marker flag for volume @vol. Returns zero 45 * in case of success and a negative error code in case of failure. 46 */ 47 static int set_update_marker(struct ubi_device *ubi, struct ubi_volume *vol) 48 { 49 int err; 50 struct ubi_vtbl_record vtbl_rec; 51 52 dbg_gen("set update marker for volume %d", vol->vol_id); 53 54 if (vol->upd_marker) { 55 ubi_assert(ubi->vtbl[vol->vol_id].upd_marker); 56 dbg_gen("already set"); 57 return 0; 58 } 59 60 vtbl_rec = ubi->vtbl[vol->vol_id]; 61 vtbl_rec.upd_marker = 1; 62 63 mutex_lock(&ubi->device_mutex); 64 err = ubi_change_vtbl_record(ubi, vol->vol_id, &vtbl_rec); 65 vol->upd_marker = 1; 66 mutex_unlock(&ubi->device_mutex); 67 return err; 68 } 69 70 /** 71 * clear_update_marker - clear update marker. 72 * @ubi: UBI device description object 73 * @vol: volume description object 74 * @bytes: new data size in bytes 75 * 76 * This function clears the update marker for volume @vol, sets new volume 77 * data size and clears the "corrupted" flag (static volumes only). Returns 78 * zero in case of success and a negative error code in case of failure. 79 */ 80 static int clear_update_marker(struct ubi_device *ubi, struct ubi_volume *vol, 81 long long bytes) 82 { 83 int err; 84 struct ubi_vtbl_record vtbl_rec; 85 86 dbg_gen("clear update marker for volume %d", vol->vol_id); 87 88 vtbl_rec = ubi->vtbl[vol->vol_id]; 89 ubi_assert(vol->upd_marker && vtbl_rec.upd_marker); 90 vtbl_rec.upd_marker = 0; 91 92 if (vol->vol_type == UBI_STATIC_VOLUME) { 93 vol->corrupted = 0; 94 vol->used_bytes = bytes; 95 vol->used_ebs = div_u64_rem(bytes, vol->usable_leb_size, 96 &vol->last_eb_bytes); 97 if (vol->last_eb_bytes) 98 vol->used_ebs += 1; 99 else 100 vol->last_eb_bytes = vol->usable_leb_size; 101 } 102 103 mutex_lock(&ubi->device_mutex); 104 err = ubi_change_vtbl_record(ubi, vol->vol_id, &vtbl_rec); 105 vol->upd_marker = 0; 106 mutex_unlock(&ubi->device_mutex); 107 return err; 108 } 109 110 /** 111 * ubi_start_update - start volume update. 112 * @ubi: UBI device description object 113 * @vol: volume description object 114 * @bytes: update bytes 115 * 116 * This function starts volume update operation. If @bytes is zero, the volume 117 * is just wiped out. Returns zero in case of success and a negative error code 118 * in case of failure. 119 */ 120 int ubi_start_update(struct ubi_device *ubi, struct ubi_volume *vol, 121 long long bytes) 122 { 123 int i, err; 124 125 dbg_gen("start update of volume %d, %llu bytes", vol->vol_id, bytes); 126 ubi_assert(!vol->updating && !vol->changing_leb); 127 vol->updating = 1; 128 129 vol->upd_buf = vmalloc(ubi->leb_size); 130 if (!vol->upd_buf) 131 return -ENOMEM; 132 133 err = set_update_marker(ubi, vol); 134 if (err) 135 return err; 136 137 /* Before updating - wipe out the volume */ 138 for (i = 0; i < vol->reserved_pebs; i++) { 139 err = ubi_eba_unmap_leb(ubi, vol, i); 140 if (err) 141 return err; 142 } 143 144 if (bytes == 0) { 145 err = ubi_wl_flush(ubi, UBI_ALL, UBI_ALL); 146 if (err) 147 return err; 148 149 err = clear_update_marker(ubi, vol, 0); 150 if (err) 151 return err; 152 153 vfree(vol->upd_buf); 154 vol->updating = 0; 155 return 0; 156 } 157 158 vol->upd_ebs = div_u64(bytes + vol->usable_leb_size - 1, 159 vol->usable_leb_size); 160 vol->upd_bytes = bytes; 161 vol->upd_received = 0; 162 return 0; 163 } 164 165 /** 166 * ubi_start_leb_change - start atomic LEB change. 167 * @ubi: UBI device description object 168 * @vol: volume description object 169 * @req: operation request 170 * 171 * This function starts atomic LEB change operation. Returns zero in case of 172 * success and a negative error code in case of failure. 173 */ 174 int ubi_start_leb_change(struct ubi_device *ubi, struct ubi_volume *vol, 175 const struct ubi_leb_change_req *req) 176 { 177 ubi_assert(!vol->updating && !vol->changing_leb); 178 179 dbg_gen("start changing LEB %d:%d, %u bytes", 180 vol->vol_id, req->lnum, req->bytes); 181 if (req->bytes == 0) 182 return ubi_eba_atomic_leb_change(ubi, vol, req->lnum, NULL, 0); 183 184 vol->upd_bytes = req->bytes; 185 vol->upd_received = 0; 186 vol->changing_leb = 1; 187 vol->ch_lnum = req->lnum; 188 189 vol->upd_buf = vmalloc(req->bytes); 190 if (!vol->upd_buf) 191 return -ENOMEM; 192 193 return 0; 194 } 195 196 /** 197 * write_leb - write update data. 198 * @ubi: UBI device description object 199 * @vol: volume description object 200 * @lnum: logical eraseblock number 201 * @buf: data to write 202 * @len: data size 203 * @used_ebs: how many logical eraseblocks will this volume contain (static 204 * volumes only) 205 * 206 * This function writes update data to corresponding logical eraseblock. In 207 * case of dynamic volume, this function checks if the data contains 0xFF bytes 208 * at the end. If yes, the 0xFF bytes are cut and not written. So if the whole 209 * buffer contains only 0xFF bytes, the LEB is left unmapped. 210 * 211 * The reason why we skip the trailing 0xFF bytes in case of dynamic volume is 212 * that we want to make sure that more data may be appended to the logical 213 * eraseblock in future. Indeed, writing 0xFF bytes may have side effects and 214 * this PEB won't be writable anymore. So if one writes the file-system image 215 * to the UBI volume where 0xFFs mean free space - UBI makes sure this free 216 * space is writable after the update. 217 * 218 * We do not do this for static volumes because they are read-only. But this 219 * also cannot be done because we have to store per-LEB CRC and the correct 220 * data length. 221 * 222 * This function returns zero in case of success and a negative error code in 223 * case of failure. 224 */ 225 static int write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum, 226 void *buf, int len, int used_ebs) 227 { 228 int err; 229 230 if (vol->vol_type == UBI_DYNAMIC_VOLUME) { 231 int l = ALIGN(len, ubi->min_io_size); 232 233 memset(buf + len, 0xFF, l - len); 234 len = ubi_calc_data_len(ubi, buf, l); 235 if (len == 0) { 236 dbg_gen("all %d bytes contain 0xFF - skip", len); 237 return 0; 238 } 239 240 err = ubi_eba_write_leb(ubi, vol, lnum, buf, 0, len); 241 } else { 242 /* 243 * When writing static volume, and this is the last logical 244 * eraseblock, the length (@len) does not have to be aligned to 245 * the minimal flash I/O unit. The 'ubi_eba_write_leb_st()' 246 * function accepts exact (unaligned) length and stores it in 247 * the VID header. And it takes care of proper alignment by 248 * padding the buffer. Here we just make sure the padding will 249 * contain zeros, not random trash. 250 */ 251 memset(buf + len, 0, vol->usable_leb_size - len); 252 err = ubi_eba_write_leb_st(ubi, vol, lnum, buf, len, used_ebs); 253 } 254 255 return err; 256 } 257 258 /** 259 * ubi_more_update_data - write more update data. 260 * @ubi: UBI device description object 261 * @vol: volume description object 262 * @buf: write data (user-space memory buffer) 263 * @count: how much bytes to write 264 * 265 * This function writes more data to the volume which is being updated. It may 266 * be called arbitrary number of times until all the update data arriveis. This 267 * function returns %0 in case of success, number of bytes written during the 268 * last call if the whole volume update has been successfully finished, and a 269 * negative error code in case of failure. 270 */ 271 int ubi_more_update_data(struct ubi_device *ubi, struct ubi_volume *vol, 272 const void __user *buf, int count) 273 { 274 #ifndef __UBOOT__ 275 int lnum, offs, err = 0, len, to_write = count; 276 #else 277 int lnum, err = 0, len, to_write = count; 278 u32 offs; 279 #endif 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