sys/vfs/hammer/hammer_recover.c

   1 /*
   2  * Copyright (c) 2008 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@backplane.com>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  * $DragonFly: src/sys/vfs/hammer/hammer_recover.c,v 1.18 2008/05/18 01:48:50 dillon Exp $
  35  */
  36
  37 #include "hammer.h"
  38
  39 static int hammer_check_tail_signature(hammer_fifo_tail_t tail,
  40                         hammer_off_t end_off);
  41 static void hammer_recover_copy_undo(hammer_off_t undo_offset,
  42                         char *src, char *dst, int bytes);
  43 #if 0
  44 static void hammer_recover_debug_dump(int w, char *buf, int bytes);
  45 #endif
  46 static int hammer_recover_undo(hammer_mount_t hmp, hammer_fifo_undo_t undo,
  47                         int bytes);
  48
  49 /*
  50  * Recover a filesystem on mount
  51  *
  52  * NOTE: No information from the root volume has been cached in the
  53  * hammer_mount structure yet, so we need to access the root volume's
  54  * buffer directly.
  55  */
  56 int
  57 hammer_recover(hammer_mount_t hmp, hammer_volume_t root_volume)
  58 {
  59         hammer_blockmap_t rootmap;
  60         hammer_buffer_t buffer;
  61         hammer_off_t scan_offset;
  62         hammer_off_t bytes;
  63         hammer_fifo_tail_t tail;
  64         hammer_fifo_undo_t undo;
  65         int error;
  66
  67         /*
  68          * Examine the UNDO FIFO.  If it is empty the filesystem is clean
  69          * and no action need be taken.
  70          *
  71          * NOTE: hmp->blockmap has not been initialized yet so use the
  72          * root volume's ondisk buffer directly.
  73          */
  74         rootmap = &root_volume->ondisk->vol0_blockmap[HAMMER_ZONE_UNDO_INDEX];
  75         hmp->flusher_undo_start = rootmap->next_offset;
  76
  77         if (rootmap->first_offset == rootmap->next_offset)
  78                 return(0);
  79
  80         if (rootmap->next_offset >= rootmap->first_offset) {
  81                 bytes = rootmap->next_offset - rootmap->first_offset;
  82         } else {
  83                 bytes = rootmap->alloc_offset - rootmap->first_offset +
  84                         (rootmap->next_offset & HAMMER_OFF_LONG_MASK);
  85         }
  86         kprintf("HAMMER(%s) Start Recovery %016llx - %016llx "
  87                 "(%lld bytes of UNDO)\n",
  88                 root_volume->ondisk->vol_name,
  89                 rootmap->first_offset, rootmap->next_offset,
  90                 bytes);
  91         if (bytes > (rootmap->alloc_offset & HAMMER_OFF_LONG_MASK)) {
  92                 kprintf("Undo size is absurd, unable to mount\n");
  93                 return(EIO);
  94         }
  95
  96         /*
  97          * Scan the UNDOs backwards.
  98          */
  99         scan_offset = rootmap->next_offset;
 100         buffer = NULL;
 101         if (scan_offset > rootmap->alloc_offset) {
 102                 kprintf("HAMMER(%s) UNDO record at %016llx FIFO overflow\n",
 103                         root_volume->ondisk->vol_name,
 104                         scan_offset);
 105                 error = EIO;
 106                 goto done;
 107         }
 108
 109         while ((int64_t)bytes > 0) {
 110                 if (hammer_debug_general & 0x0080)
 111                         kprintf("scan_offset %016llx\n", scan_offset);
 112                 if (scan_offset == HAMMER_ZONE_ENCODE(HAMMER_ZONE_UNDO_INDEX, 0)) {
 113                         scan_offset = rootmap->alloc_offset;
 114                         continue;
 115                 }
 116                 if (scan_offset - sizeof(*tail) <
 117                     HAMMER_ZONE_ENCODE(HAMMER_ZONE_UNDO_INDEX, 0)) {
 118                         kprintf("HAMMER(%s) UNDO record at %016llx FIFO "
 119                                 "underflow\n",
 120                                 root_volume->ondisk->vol_name,
 121                                 scan_offset);
 122                         error = EIO;
 123                         break;
 124                 }
 125                 tail = hammer_bread(hmp, scan_offset - sizeof(*tail),
 126                                     &error, &buffer);
 127                 if (error) {
 128                         kprintf("HAMMER(%s) Unable to read UNDO TAIL "
 129                                 "at %016llx\n",
 130                                 root_volume->ondisk->vol_name,
 131                                 scan_offset - sizeof(*tail));
 132                         break;
 133                 }
 134
 135                 if (hammer_check_tail_signature(tail, scan_offset) != 0) {
 136                         kprintf("HAMMER(%s) Illegal UNDO TAIL signature "
 137                                 "at %016llx\n",
 138                                 root_volume->ondisk->vol_name,
 139                                 scan_offset - sizeof(*tail));
 140                         error = EIO;
 141                         break;
 142                 }
 143                 undo = (void *)((char *)tail + sizeof(*tail) - tail->tail_size);
 144
 145                 error = hammer_recover_undo(hmp, undo,
 146                                 HAMMER_BUFSIZE -
 147                                 (int)((char *)undo - (char *)buffer->ondisk));
 148                 if (error) {
 149                         kprintf("HAMMER(%s) UNDO record at %016llx failed\n",
 150                                 root_volume->ondisk->vol_name,
 151                                 scan_offset - tail->tail_size);
 152                         break;
 153                 }
 154                 scan_offset -= tail->tail_size;
 155                 bytes -= tail->tail_size;
 156         }
 157 done:
 158         /*
 159          * Reload flusher_undo_start to kick off the UNDO sequencing.
 160          */
 161         hmp->flusher_undo_start = rootmap->next_offset;
 162         if (buffer)
 163                 hammer_rel_buffer(buffer, 0);
 164         return (error);
 165 }
 166
 167 static int
 168 hammer_check_tail_signature(hammer_fifo_tail_t tail, hammer_off_t end_off)
 169 {
 170         int max_bytes;
 171
 172         max_bytes = ((end_off - sizeof(*tail)) & HAMMER_BUFMASK);
 173         max_bytes += sizeof(*tail);
 174
 175         /*
 176          * tail overlaps buffer boundary
 177          */
 178         if (((end_off - sizeof(*tail)) ^ (end_off - 1)) & ~HAMMER_BUFMASK64) {
 179                 return(1);
 180         }
 181
 182         /*
 183          * signature check, the tail signature is allowed to be the head
 184          * signature only for 8-byte PADs.
 185          */
 186         switch(tail->tail_signature) {
 187         case HAMMER_TAIL_SIGNATURE:
 188                 break;
 189         case HAMMER_HEAD_SIGNATURE:
 190                 if (tail->tail_type != HAMMER_HEAD_TYPE_PAD ||
 191                     tail->tail_size != sizeof(*tail)) {
 192                         return(2);
 193                 }
 194                 break;
 195         }
 196
 197         /*
 198          * The undo structure must not overlap a buffer boundary.
 199          */
 200         if (tail->tail_size < 0 || tail->tail_size > max_bytes) {
 201                 return(3);
 202         }
 203         return(0);
 204 }
 205
 206 static int
 207 hammer_recover_undo(hammer_mount_t hmp, hammer_fifo_undo_t undo, int bytes)
 208 {
 209         hammer_fifo_tail_t tail;
 210         hammer_volume_t volume;
 211         hammer_buffer_t buffer;
 212         hammer_off_t buf_offset;
 213         int zone;
 214         int error;
 215         int vol_no;
 216         int max_bytes;
 217         u_int32_t offset;
 218         u_int32_t crc;
 219
 220         /*
 221          * Basic sanity checks
 222          */
 223         if (bytes < HAMMER_HEAD_ALIGN) {
 224                 kprintf("HAMMER: Undo alignment error (%d)\n", bytes);
 225                 return(EIO);
 226         }
 227         if (undo->head.hdr_signature != HAMMER_HEAD_SIGNATURE) {
 228                 kprintf("HAMMER: Bad head signature %04x\n",
 229                         undo->head.hdr_signature);
 230                 return(EIO);
 231         }
 232         if (undo->head.hdr_size < HAMMER_HEAD_ALIGN ||
 233             undo->head.hdr_size > bytes) {
 234                 kprintf("HAMMER: Bad size %d\n", bytes);
 235                 return(EIO);
 236         }
 237
 238         /*
 239          * Skip PAD records.  Note that PAD records also do not require
 240          * a tail and may have a truncated structure.
 241          */
 242         if (undo->head.hdr_type == HAMMER_HEAD_TYPE_PAD)
 243                 return(0);
 244
 245         /*
 246          * Check the CRC
 247          */
 248         crc = crc32(undo, HAMMER_FIFO_HEAD_CRCOFF) ^
 249               crc32(&undo->head + 1, undo->head.hdr_size - sizeof(undo->head));
 250         if (undo->head.hdr_crc != crc) {
 251                 kprintf("HAMMER: Undo record CRC failed %08x %08x\n",
 252                         undo->head.hdr_crc, crc);
 253                 return(EIO);
 254         }
 255
 256
 257         /*
 258          * Check the tail
 259          */
 260         bytes = undo->head.hdr_size;
 261         tail = (void *)((char *)undo + bytes - sizeof(*tail));
 262         if (tail->tail_size != undo->head.hdr_size) {
 263                 kprintf("HAMMER: Bad tail size %d\n", tail->tail_size);
 264                 return(EIO);
 265         }
 266         if (tail->tail_type != undo->head.hdr_type) {
 267                 kprintf("HAMMER: Bad tail type %d\n", tail->tail_type);
 268                 return(EIO);
 269         }
 270
 271         /*
 272          * Only process UNDO records
 273          */
 274         if (undo->head.hdr_type != HAMMER_HEAD_TYPE_UNDO)
 275                 return(0);
 276
 277         /*
 278          * Validate the UNDO record.
 279          */
 280         max_bytes = undo->head.hdr_size - sizeof(*undo) - sizeof(*tail);
 281         if (undo->undo_data_bytes < 0 || undo->undo_data_bytes > max_bytes) {
 282                 kprintf("HAMMER: Corrupt UNDO record, undo_data_bytes %d/%d\n",
 283                         undo->undo_data_bytes, max_bytes);
 284                 return(EIO);
 285         }
 286
 287         /*
 288          * The undo offset may only be a zone-1 or zone-2 offset.
 289          *
 290          * Currently we only support a zone-1 offset representing the
 291          * volume header.
 292          */
 293         zone = HAMMER_ZONE_DECODE(undo->undo_offset);
 294         offset = undo->undo_offset & HAMMER_BUFMASK;
 295
 296         if (offset + undo->undo_data_bytes > HAMMER_BUFSIZE) {
 297                 kprintf("HAMMER: Corrupt UNDO record, bad offset\n");
 298                 return (EIO);
 299         }
 300
 301         switch(zone) {
 302         case HAMMER_ZONE_RAW_VOLUME_INDEX:
 303                 vol_no = HAMMER_VOL_DECODE(undo->undo_offset);
 304                 volume = hammer_get_volume(hmp, vol_no, &error);
 305                 if (volume == NULL) {
 306                         kprintf("HAMMER: UNDO record, "
 307                                 "cannot access volume %d\n", vol_no);
 308                         break;
 309                 }
 310                 hammer_modify_volume(NULL, volume, NULL, 0);
 311                 hammer_recover_copy_undo(undo->undo_offset,
 312                                          (char *)(undo + 1),
 313                                          (char *)volume->ondisk + offset,
 314                                          undo->undo_data_bytes);
 315                 hammer_modify_volume_done(volume);
 316                 hammer_io_flush(&volume->io);
 317                 hammer_rel_volume(volume, 0);
 318                 break;
 319         case HAMMER_ZONE_RAW_BUFFER_INDEX:
 320                 buf_offset = undo->undo_offset & ~HAMMER_BUFMASK64;
 321                 buffer = hammer_get_buffer(hmp, buf_offset, 0, &error);
 322                 if (buffer == NULL) {
 323                         kprintf("HAMMER: UNDO record, "
 324                                 "cannot access buffer %016llx\n",
 325                                 undo->undo_offset);
 326                         break;
 327                 }
 328                 hammer_modify_buffer(NULL, buffer, NULL, 0);
 329                 hammer_recover_copy_undo(undo->undo_offset,
 330                                          (char *)(undo + 1),
 331                                          (char *)buffer->ondisk + offset,
 332                                          undo->undo_data_bytes);
 333                 hammer_modify_buffer_done(buffer);
 334                 hammer_io_flush(&buffer->io);
 335                 hammer_rel_buffer(buffer, 0);
 336                 break;
 337         default:
 338                 kprintf("HAMMER: Corrupt UNDO record\n");
 339                 error = EIO;
 340         }
 341         return (error);
 342 }
 343
 344 static void
 345 hammer_recover_copy_undo(hammer_off_t undo_offset,
 346                          char *src, char *dst, int bytes)
 347 {
 348         hkprintf("U");
 349         if (hammer_debug_general & 0x0080)
 350                 kprintf("NDO %016llx: %d\n", undo_offset, bytes);
 351 #if 0
 352         kprintf("UNDO %016llx:", undo_offset);
 353         hammer_recover_debug_dump(22, dst, bytes);
 354         kprintf("%22s", "to:");
 355         hammer_recover_debug_dump(22, src, bytes);
 356 #endif
 357         bcopy(src, dst, bytes);
 358 }
 359
 360 #if 0
 361
 362 static void
 363 hammer_recover_debug_dump(int w, char *buf, int bytes)
 364 {
 365         int i;
 366
 367         for (i = 0; i < bytes; ++i) {
 368                 if (i && (i & 15) == 0)
 369                         kprintf("\n%*.*s", w, w, "");
 370                 kprintf(" %02x", (unsigned char)buf[i]);
 371         }
 372         kprintf("\n");
 373 }
 374
 375 #endif