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 = clear_update_marker(ubi, vol, 0);
 151                 if (err)
 152                         return err;
 153                 err = ubi_wl_flush(ubi);
 154                 if (!err)
 155                         vol->updating = 0;
 156         }
 157
 158         vol->upd_buf = vmalloc(ubi->leb_size);
 159         if (!vol->upd_buf)
 160                 return -ENOMEM;
 161
 162         vol->upd_ebs = div_u64(bytes + vol->usable_leb_size - 1,
 163                                vol->usable_leb_size);
 164         vol->upd_bytes = bytes;
 165         vol->upd_received = 0;
 166         return 0;
 167 }
 168
 169 /**
 170  * ubi_start_leb_change - start atomic LEB change.
 171  * @ubi: UBI device description object
 172  * @vol: volume description object
 173  * @req: operation request
 174  *
 175  * This function starts atomic LEB change operation. Returns zero in case of
 176  * success and a negative error code in case of failure.
 177  */
 178 int ubi_start_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
 179                          const struct ubi_leb_change_req *req)
 180 {
 181         ubi_assert(!vol->updating && !vol->changing_leb);
 182
 183         dbg_gen("start changing LEB %d:%d, %u bytes",
 184                 vol->vol_id, req->lnum, req->bytes);
 185         if (req->bytes == 0)
 186                 return ubi_eba_atomic_leb_change(ubi, vol, req->lnum, NULL, 0,
 187                                                  req->dtype);
 188
 189         vol->upd_bytes = req->bytes;
 190         vol->upd_received = 0;
 191         vol->changing_leb = 1;
 192         vol->ch_lnum = req->lnum;
 193         vol->ch_dtype = req->dtype;
 194
 195         vol->upd_buf = vmalloc(req->bytes);
 196         if (!vol->upd_buf)
 197                 return -ENOMEM;
 198
 199         return 0;
 200 }
 201
 202 /**
 203  * write_leb - write update data.
 204  * @ubi: UBI device description object
 205  * @vol: volume description object
 206  * @lnum: logical eraseblock number
 207  * @buf: data to write
 208  * @len: data size
 209  * @used_ebs: how many logical eraseblocks will this volume contain (static
 210  * volumes only)
 211  *
 212  * This function writes update data to corresponding logical eraseblock. In
 213  * case of dynamic volume, this function checks if the data contains 0xFF bytes
 214  * at the end. If yes, the 0xFF bytes are cut and not written. So if the whole
 215  * buffer contains only 0xFF bytes, the LEB is left unmapped.
 216  *
 217  * The reason why we skip the trailing 0xFF bytes in case of dynamic volume is
 218  * that we want to make sure that more data may be appended to the logical
 219  * eraseblock in future. Indeed, writing 0xFF bytes may have side effects and
 220  * this PEB won't be writable anymore. So if one writes the file-system image
 221  * to the UBI volume where 0xFFs mean free space - UBI makes sure this free
 222  * space is writable after the update.
 223  *
 224  * We do not do this for static volumes because they are read-only. But this
 225  * also cannot be done because we have to store per-LEB CRC and the correct
 226  * data length.
 227  *
 228  * This function returns zero in case of success and a negative error code in
 229  * case of failure.
 230  */
 231 static int write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
 232                      void *buf, int len, int used_ebs)
 233 {
 234         int err;
 235
 236         if (vol->vol_type == UBI_DYNAMIC_VOLUME) {
 237                 int l = ALIGN(len, ubi->min_io_size);
 238
 239                 memset(buf + len, 0xFF, l - len);
 240                 len = ubi_calc_data_len(ubi, buf, l);
 241                 if (len == 0) {
 242                         dbg_gen("all %d bytes contain 0xFF - skip", len);
 243                         return 0;
 244                 }
 245
 246                 err = ubi_eba_write_leb(ubi, vol, lnum, buf, 0, len,
 247                                         UBI_UNKNOWN);
 248         } else {
 249                 /*
 250                  * When writing static volume, and this is the last logical
 251                  * eraseblock, the length (@len) does not have to be aligned to
 252                  * the minimal flash I/O unit. The 'ubi_eba_write_leb_st()'
 253                  * function accepts exact (unaligned) length and stores it in
 254                  * the VID header. And it takes care of proper alignment by
 255                  * padding the buffer. Here we just make sure the padding will
 256                  * contain zeros, not random trash.
 257                  */
 258                 memset(buf + len, 0, vol->usable_leb_size - len);
 259                 err = ubi_eba_write_leb_st(ubi, vol, lnum, buf, len,
 260                                            UBI_UNKNOWN, used_ebs);
 261         }
 262
 263         return err;
 264 }
 265
 266 /**
 267  * ubi_more_update_data - write more update data.
 268  * @ubi: UBI device description object
 269  * @vol: volume description object
 270  * @buf: write data (user-space memory buffer)
 271  * @count: how much bytes to write
 272  *
 273  * This function writes more data to the volume which is being updated. It may
 274  * be called arbitrary number of times until all the update data arriveis. This
 275  * function returns %0 in case of success, number of bytes written during the
 276  * last call if the whole volume update has been successfully finished, and a
 277  * negative error code in case of failure.
 278  */
 279 int ubi_more_update_data(struct ubi_device *ubi, struct ubi_volume *vol,
 280                          const void __user *buf, int count)
 281 {
 282         int lnum, offs, err = 0, len, to_write = count;
 283
 284         dbg_gen("write %d of %lld bytes, %lld already passed",
 285                 count, vol->upd_bytes, vol->upd_received);
 286
 287         if (ubi->ro_mode)
 288                 return -EROFS;
 289
 290         lnum = div_u64_rem(vol->upd_received,  vol->usable_leb_size, &offs);
 291         if (vol->upd_received + count > vol->upd_bytes)
 292                 to_write = count = vol->upd_bytes - vol->upd_received;
 293
 294         /*
 295          * When updating volumes, we accumulate whole logical eraseblock of
 296          * data and write it at once.
 297          */
 298         if (offs != 0) {
 299                 /*
 300                  * This is a write to the middle of the logical eraseblock. We
 301                  * copy the data to our update buffer and wait for more data or
 302                  * flush it if the whole eraseblock is written or the update
 303                  * is finished.
 304                  */
 305
 306                 len = vol->usable_leb_size - offs;
 307                 if (len > count)
 308                         len = count;
 309
 310                 err = copy_from_user(vol->upd_buf + offs, buf, len);
 311                 if (err)
 312                         return -EFAULT;
 313
 314                 if (offs + len == vol->usable_leb_size ||
 315                     vol->upd_received + len == vol->upd_bytes) {
 316                         int flush_len = offs + len;
 317
 318                         /*
 319                          * OK, we gathered either the whole eraseblock or this
 320                          * is the last chunk, it's time to flush the buffer.
 321                          */
 322                         ubi_assert(flush_len <= vol->usable_leb_size);
 323                         err = write_leb(ubi, vol, lnum, vol->upd_buf, flush_len,
 324                                         vol->upd_ebs);
 325                         if (err)
 326                                 return err;
 327                 }
 328
 329                 vol->upd_received += len;
 330                 count -= len;
 331                 buf += len;
 332                 lnum += 1;
 333         }
 334
 335         /*
 336          * If we've got more to write, let's continue. At this point we know we
 337          * are starting from the beginning of an eraseblock.
 338          */
 339         while (count) {
 340                 if (count > vol->usable_leb_size)
 341                         len = vol->usable_leb_size;
 342                 else
 343                         len = count;
 344
 345                 err = copy_from_user(vol->upd_buf, buf, len);
 346                 if (err)
 347                         return -EFAULT;
 348
 349                 if (len == vol->usable_leb_size ||
 350                     vol->upd_received + len == vol->upd_bytes) {
 351                         err = write_leb(ubi, vol, lnum, vol->upd_buf,
 352                                         len, vol->upd_ebs);
 353                         if (err)
 354                                 break;
 355                 }
 356
 357                 vol->upd_received += len;
 358                 count -= len;
 359                 lnum += 1;
 360                 buf += len;
 361         }
 362
 363         ubi_assert(vol->upd_received <= vol->upd_bytes);
 364         if (vol->upd_received == vol->upd_bytes) {
 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                 err = ubi_wl_flush(ubi);
 370                 if (err == 0) {
 371                         vol->updating = 0;
 372                         err = to_write;
 373                         vfree(vol->upd_buf);
 374                 }
 375         }
 376
 377         return err;
 378 }
 379
 380 /**
 381  * ubi_more_leb_change_data - accept more data for atomic LEB change.
 382  * @ubi: UBI device description object
 383  * @vol: volume description object
 384  * @buf: write data (user-space memory buffer)
 385  * @count: how much bytes to write
 386  *
 387  * This function accepts more data to the volume which is being under the
 388  * "atomic LEB change" operation. It may be called arbitrary number of times
 389  * until all data arrives. This function returns %0 in case of success, number
 390  * of bytes written during the last call if the whole "atomic LEB change"
 391  * operation has been successfully finished, and a negative error code in case
 392  * of failure.
 393  */
 394 int ubi_more_leb_change_data(struct ubi_device *ubi, struct ubi_volume *vol,
 395                              const void __user *buf, int count)
 396 {
 397         int err;
 398
 399         dbg_gen("write %d of %lld bytes, %lld already passed",
 400                 count, vol->upd_bytes, vol->upd_received);
 401
 402         if (ubi->ro_mode)
 403                 return -EROFS;
 404
 405         if (vol->upd_received + count > vol->upd_bytes)
 406                 count = vol->upd_bytes - vol->upd_received;
 407
 408         err = copy_from_user(vol->upd_buf + vol->upd_received, buf, count);
 409         if (err)
 410                 return -EFAULT;
 411
 412         vol->upd_received += count;
 413
 414         if (vol->upd_received == vol->upd_bytes) {
 415                 int len = ALIGN((int)vol->upd_bytes, ubi->min_io_size);
 416
 417                 memset(vol->upd_buf + vol->upd_bytes, 0xFF,
 418                        len - vol->upd_bytes);
 419                 len = ubi_calc_data_len(ubi, vol->upd_buf, len);
 420                 err = ubi_eba_atomic_leb_change(ubi, vol, vol->ch_lnum,
 421                                                 vol->upd_buf, len, UBI_UNKNOWN);
 422                 if (err)
 423                         return err;
 424         }
 425
 426         ubi_assert(vol->upd_received <= vol->upd_bytes);
 427         if (vol->upd_received == vol->upd_bytes) {
 428                 vol->changing_leb = 0;
 429                 err = count;
 430                 vfree(vol->upd_buf);
 431         }
 432
 433         return err;
 434 }