drivers/mtd/ubi/upd.c

   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         memcpy(&vtbl_rec, &ubi->vtbl[vol->vol_id],
  68                sizeof(struct ubi_vtbl_record));
  69         vtbl_rec.upd_marker = 1;
  70
  71         mutex_lock(&ubi->device_mutex);
  72         err = ubi_change_vtbl_record(ubi, vol->vol_id, &vtbl_rec);
  73         vol->upd_marker = 1;
  74         mutex_unlock(&ubi->device_mutex);
  75         return err;
  76 }
  77
  78 /**
  79  * clear_update_marker - clear update marker.
  80  * @ubi: UBI device description object
  81  * @vol: volume description object
  82  * @bytes: new data size in bytes
  83  *
  84  * This function clears the update marker for volume @vol, sets new volume
  85  * data size and clears the "corrupted" flag (static volumes only). Returns
  86  * zero in case of success and a negative error code in case of failure.
  87  */
  88 static int clear_update_marker(struct ubi_device *ubi, struct ubi_volume *vol,
  89                                long long bytes)
  90 {
  91         int err;
  92         struct ubi_vtbl_record vtbl_rec;
  93
  94         dbg_gen("clear update marker for volume %d", vol->vol_id);
  95
  96         memcpy(&vtbl_rec, &ubi->vtbl[vol->vol_id],
  97                sizeof(struct ubi_vtbl_record));
  98         ubi_assert(vol->upd_marker && vtbl_rec.upd_marker);
  99         vtbl_rec.upd_marker = 0;
 100
 101         if (vol->vol_type == UBI_STATIC_VOLUME) {
 102                 vol->corrupted = 0;
 103                 vol->used_bytes = bytes;
 104                 vol->used_ebs = div_u64_rem(bytes, vol->usable_leb_size,
 105                                             &vol->last_eb_bytes);
 106                 if (vol->last_eb_bytes)
 107                         vol->used_ebs += 1;
 108                 else
 109                         vol->last_eb_bytes = vol->usable_leb_size;
 110         }
 111
 112         mutex_lock(&ubi->device_mutex);
 113         err = ubi_change_vtbl_record(ubi, vol->vol_id, &vtbl_rec);
 114         vol->upd_marker = 0;
 115         mutex_unlock(&ubi->device_mutex);
 116         return err;
 117 }
 118
 119 /**
 120  * ubi_start_update - start volume update.
 121  * @ubi: UBI device description object
 122  * @vol: volume description object
 123  * @bytes: update bytes
 124  *
 125  * This function starts volume update operation. If @bytes is zero, the volume
 126  * is just wiped out. Returns zero in case of success and a negative error code
 127  * in case of failure.
 128  */
 129 int ubi_start_update(struct ubi_device *ubi, struct ubi_volume *vol,
 130                      long long bytes)
 131 {
 132         int i, err;
 133
 134         dbg_gen("start update of volume %d, %llu bytes", vol->vol_id, bytes);
 135         ubi_assert(!vol->updating && !vol->changing_leb);
 136         vol->updating = 1;
 137
 138         err = set_update_marker(ubi, vol);
 139         if (err)
 140                 return err;
 141
 142         /* Before updating - wipe out the volume */
 143         for (i = 0; i < vol->reserved_pebs; i++) {
 144                 err = ubi_eba_unmap_leb(ubi, vol, i);
 145                 if (err)
 146                         return err;
 147         }
 148
 149         if (bytes == 0) {
 150                 err = ubi_wl_flush(ubi);
 151                 if (err)
 152                         return err;
 153
 154                 err = clear_update_marker(ubi, vol, 0);
 155                 if (err)
 156                         return err;
 157                 vol->updating = 0;
 158                 return 0;
 159         }
 160
 161         vol->upd_buf = vmalloc(ubi->leb_size);
 162         if (!vol->upd_buf)
 163                 return -ENOMEM;
 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                                                  req->dtype);
 191
 192         vol->upd_bytes = req->bytes;
 193         vol->upd_received = 0;
 194         vol->changing_leb = 1;
 195         vol->ch_lnum = req->lnum;
 196         vol->ch_dtype = req->dtype;
 197
 198         vol->upd_buf = vmalloc(req->bytes);
 199         if (!vol->upd_buf)
 200                 return -ENOMEM;
 201
 202         return 0;
 203 }
 204
 205 /**
 206  * write_leb - write update data.
 207  * @ubi: UBI device description object
 208  * @vol: volume description object
 209  * @lnum: logical eraseblock number
 210  * @buf: data to write
 211  * @len: data size
 212  * @used_ebs: how many logical eraseblocks will this volume contain (static
 213  * volumes only)
 214  *
 215  * This function writes update data to corresponding logical eraseblock. In
 216  * case of dynamic volume, this function checks if the data contains 0xFF bytes
 217  * at the end. If yes, the 0xFF bytes are cut and not written. So if the whole
 218  * buffer contains only 0xFF bytes, the LEB is left unmapped.
 219  *
 220  * The reason why we skip the trailing 0xFF bytes in case of dynamic volume is
 221  * that we want to make sure that more data may be appended to the logical
 222  * eraseblock in future. Indeed, writing 0xFF bytes may have side effects and
 223  * this PEB won't be writable anymore. So if one writes the file-system image
 224  * to the UBI volume where 0xFFs mean free space - UBI makes sure this free
 225  * space is writable after the update.
 226  *
 227  * We do not do this for static volumes because they are read-only. But this
 228  * also cannot be done because we have to store per-LEB CRC and the correct
 229  * data length.
 230  *
 231  * This function returns zero in case of success and a negative error code in
 232  * case of failure.
 233  */
 234 static int write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
 235                      void *buf, int len, int used_ebs)
 236 {
 237         int err;
 238
 239         if (vol->vol_type == UBI_DYNAMIC_VOLUME) {
 240                 int l = ALIGN(len, ubi->min_io_size);
 241
 242                 memset(buf + len, 0xFF, l - len);
 243                 len = ubi_calc_data_len(ubi, buf, l);
 244                 if (len == 0) {
 245                         dbg_gen("all %d bytes contain 0xFF - skip", len);
 246                         return 0;
 247                 }
 248
 249                 err = ubi_eba_write_leb(ubi, vol, lnum, buf, 0, len,
 250                                         UBI_UNKNOWN);
 251         } else {
 252                 /*
 253                  * When writing static volume, and this is the last logical
 254                  * eraseblock, the length (@len) does not have to be aligned to
 255                  * the minimal flash I/O unit. The 'ubi_eba_write_leb_st()'
 256                  * function accepts exact (unaligned) length and stores it in
 257                  * the VID header. And it takes care of proper alignment by
 258                  * padding the buffer. Here we just make sure the padding will
 259                  * contain zeros, not random trash.
 260                  */
 261                 memset(buf + len, 0, vol->usable_leb_size - len);
 262                 err = ubi_eba_write_leb_st(ubi, vol, lnum, buf, len,
 263                                            UBI_UNKNOWN, used_ebs);
 264         }
 265
 266         return err;
 267 }
 268
 269 /**
 270  * ubi_more_update_data - write more update data.
 271  * @ubi: UBI device description object
 272  * @vol: volume description object
 273  * @buf: write data (user-space memory buffer)
 274  * @count: how much bytes to write
 275  *
 276  * This function writes more data to the volume which is being updated. It may
 277  * be called arbitrary number of times until all the update data arriveis. This
 278  * function returns %0 in case of success, number of bytes written during the
 279  * last call if the whole volume update has been successfully finished, and a
 280  * negative error code in case of failure.
 281  */
 282 int ubi_more_update_data(struct ubi_device *ubi, struct ubi_volume *vol,
 283                          const void __user *buf, int count)
 284 {
 285         int lnum, offs, err = 0, len, to_write = count;
 286
 287         dbg_gen("write %d of %lld bytes, %lld already passed",
 288                 count, vol->upd_bytes, vol->upd_received);
 289
 290         if (ubi->ro_mode)
 291                 return -EROFS;
 292
 293         lnum = div_u64_rem(vol->upd_received,  vol->usable_leb_size, &offs);
 294         if (vol->upd_received + count > vol->upd_bytes)
 295                 to_write = count = vol->upd_bytes - vol->upd_received;
 296
 297         /*
 298          * When updating volumes, we accumulate whole logical eraseblock of
 299          * data and write it at once.
 300          */
 301         if (offs != 0) {
 302                 /*
 303                  * This is a write to the middle of the logical eraseblock. We
 304                  * copy the data to our update buffer and wait for more data or
 305                  * flush it if the whole eraseblock is written or the update
 306                  * is finished.
 307                  */
 308
 309                 len = vol->usable_leb_size - offs;
 310                 if (len > count)
 311                         len = count;
 312
 313                 err = copy_from_user(vol->upd_buf + offs, buf, len);
 314                 if (err)
 315                         return -EFAULT;
 316
 317                 if (offs + len == vol->usable_leb_size ||
 318                     vol->upd_received + len == vol->upd_bytes) {
 319                         int flush_len = offs + len;
 320
 321                         /*
 322                          * OK, we gathered either the whole eraseblock or this
 323                          * is the last chunk, it's time to flush the buffer.
 324                          */
 325                         ubi_assert(flush_len <= vol->usable_leb_size);
 326                         err = write_leb(ubi, vol, lnum, vol->upd_buf, flush_len,
 327                                         vol->upd_ebs);
 328                         if (err)
 329                                 return err;
 330                 }
 331
 332                 vol->upd_received += len;
 333                 count -= len;
 334                 buf += len;
 335                 lnum += 1;
 336         }
 337
 338         /*
 339          * If we've got more to write, let's continue. At this point we know we
 340          * are starting from the beginning of an eraseblock.
 341          */
 342         while (count) {
 343                 if (count > vol->usable_leb_size)
 344                         len = vol->usable_leb_size;
 345                 else
 346                         len = count;
 347
 348                 err = copy_from_user(vol->upd_buf, buf, len);
 349                 if (err)
 350                         return -EFAULT;
 351
 352                 if (len == vol->usable_leb_size ||
 353                     vol->upd_received + len == vol->upd_bytes) {
 354                         err = write_leb(ubi, vol, lnum, vol->upd_buf,
 355                                         len, vol->upd_ebs);
 356                         if (err)
 357                                 break;
 358                 }
 359
 360                 vol->upd_received += len;
 361                 count -= len;
 362                 lnum += 1;
 363                 buf += len;
 364         }
 365
 366         ubi_assert(vol->upd_received <= vol->upd_bytes);
 367         if (vol->upd_received == vol->upd_bytes) {
 368                 err = ubi_wl_flush(ubi);
 369                 if (err)
 370                         return err;
 371                 /* The update is finished, clear the update marker */
 372                 err = clear_update_marker(ubi, vol, vol->upd_bytes);
 373                 if (err)
 374                         return err;
 375                 vol->updating = 0;
 376                 err = to_write;
 377                 vfree(vol->upd_buf);
 378         }
 379
 380         return err;
 381 }
 382
 383 /**
 384  * ubi_more_leb_change_data - accept more data for atomic LEB change.
 385  * @ubi: UBI device description object
 386  * @vol: volume description object
 387  * @buf: write data (user-space memory buffer)
 388  * @count: how much bytes to write
 389  *
 390  * This function accepts more data to the volume which is being under the
 391  * "atomic LEB change" operation. It may be called arbitrary number of times
 392  * until all data arrives. This function returns %0 in case of success, number
 393  * of bytes written during the last call if the whole "atomic LEB change"
 394  * operation has been successfully finished, and a negative error code in case
 395  * of failure.
 396  */
 397 int ubi_more_leb_change_data(struct ubi_device *ubi, struct ubi_volume *vol,
 398                              const void __user *buf, int count)
 399 {
 400         int err;
 401
 402         dbg_gen("write %d of %lld bytes, %lld already passed",
 403                 count, vol->upd_bytes, vol->upd_received);
 404
 405         if (ubi->ro_mode)
 406                 return -EROFS;
 407
 408         if (vol->upd_received + count > vol->upd_bytes)
 409                 count = vol->upd_bytes - vol->upd_received;
 410
 411         err = copy_from_user(vol->upd_buf + vol->upd_received, buf, count);
 412         if (err)
 413                 return -EFAULT;
 414
 415         vol->upd_received += count;
 416
 417         if (vol->upd_received == vol->upd_bytes) {
 418                 int len = ALIGN((int)vol->upd_bytes, ubi->min_io_size);
 419
 420                 memset(vol->upd_buf + vol->upd_bytes, 0xFF,
 421                        len - vol->upd_bytes);
 422                 len = ubi_calc_data_len(ubi, vol->upd_buf, len);
 423                 err = ubi_eba_atomic_leb_change(ubi, vol, vol->ch_lnum,
 424                                                 vol->upd_buf, len, UBI_UNKNOWN);
 425                 if (err)
 426                         return err;
 427         }
 428
 429         ubi_assert(vol->upd_received <= vol->upd_bytes);
 430         if (vol->upd_received == vol->upd_bytes) {
 431                 vol->changing_leb = 0;
 432                 err = count;
 433                 vfree(vol->upd_buf);
 434         }
 435
 436         return err;
 437 }