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