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 1.13 2008/04/29 01:10:37 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         if (rootmap->first_offset == rootmap->next_offset)
  76                 return(0);
  77
  78         if (rootmap->next_offset < rootmap->first_offset)
  79                 bytes = rootmap->alloc_offset - rootmap->first_offset +
  80                         rootmap->next_offset;
  81         else
  82                 bytes = (rootmap->next_offset - rootmap->first_offset);
  83         kprintf("HAMMER(%s) Start Recovery (%lld bytes of UNDO)\n",
  84                 root_volume->ondisk->vol_name, bytes);
  85
  86         /*
  87          * Scan the UNDOs backwards.
  88          */
  89         scan_offset = rootmap->next_offset;
  90         buffer = NULL;
  91         if (scan_offset > rootmap->alloc_offset) {
  92                 kprintf("HAMMER(%s) UNDO record at %016llx FIFO overflow\n",
  93                         root_volume->ondisk->vol_name,
  94                         scan_offset);
  95                 error = EIO;
  96                 goto failed;
  97         }
  98
  99         while ((int64_t)bytes > 0) {
 100                 kprintf("scan_offset %016llx\n", scan_offset);
 101                 if (scan_offset == HAMMER_ZONE_ENCODE(HAMMER_ZONE_UNDO_INDEX, 0)) {
 102                         scan_offset = rootmap->alloc_offset;
 103                         continue;
 104                 }
 105                 if (scan_offset - sizeof(*tail) <
 106                     HAMMER_ZONE_ENCODE(HAMMER_ZONE_UNDO_INDEX, 0)) {
 107                         kprintf("HAMMER(%s) UNDO record at %016llx FIFO "
 108                                 "underflow\n",
 109                                 root_volume->ondisk->vol_name,
 110                                 scan_offset);
 111                         Debugger("FUBAR");
 112                         error = EIO;
 113                         break;
 114                 }
 115                 tail = hammer_bread(hmp, scan_offset - sizeof(*tail),
 116                                     &error, &buffer);
 117                 if (error) {
 118                         kprintf("HAMMER(%s) Unable to read UNDO TAIL "
 119                                 "at %016llx\n",
 120                                 root_volume->ondisk->vol_name,
 121                                 scan_offset - sizeof(*tail));
 122                         break;
 123                 }
 124
 125                 if (hammer_check_tail_signature(tail, scan_offset) != 0) {
 126                         kprintf("HAMMER(%s) Illegal UNDO TAIL signature "
 127                                 "at %016llx\n",
 128                                 root_volume->ondisk->vol_name,
 129                                 scan_offset - sizeof(*tail));
 130                         error = EIO;
 131                         break;
 132                 }
 133                 undo = (void *)((char *)tail + sizeof(*tail) - tail->tail_size);
 134
 135                 error = hammer_recover_undo(hmp, undo,
 136                                 HAMMER_BUFSIZE -
 137                                 (int)((char *)undo - (char *)buffer->ondisk));
 138                 if (error) {
 139                         kprintf("HAMMER(%s) UNDO record at %016llx failed\n",
 140                                 root_volume->ondisk->vol_name,
 141                                 scan_offset - tail->tail_size);
 142                         break;
 143                 }
 144                 scan_offset -= tail->tail_size;
 145                 bytes -= tail->tail_size;
 146         }
 147 failed:
 148         if (buffer)
 149                 hammer_rel_buffer(buffer, 0);
 150         return (error);
 151 }
 152
 153 static int
 154 hammer_check_tail_signature(hammer_fifo_tail_t tail, hammer_off_t end_off)
 155 {
 156         int max_bytes;
 157
 158         max_bytes = ((end_off - sizeof(*tail)) & HAMMER_BUFMASK);
 159         max_bytes += sizeof(*tail);
 160
 161         /*
 162          * tail overlaps buffer boundary
 163          */
 164         if (((end_off - sizeof(*tail)) ^ (end_off - 1)) & ~HAMMER_BUFMASK64) {
 165                 return(1);
 166         }
 167
 168         /*
 169          * signature check, the tail signature is allowed to be the head
 170          * signature only for 8-byte PADs.
 171          */
 172         switch(tail->tail_signature) {
 173         case HAMMER_TAIL_SIGNATURE:
 174                 break;
 175         case HAMMER_HEAD_SIGNATURE:
 176                 if (tail->tail_type != HAMMER_HEAD_TYPE_PAD ||
 177                     tail->tail_size != sizeof(*tail)) {
 178                         return(2);
 179                 }
 180                 break;
 181         }
 182
 183         /*
 184          * The undo structure must not overlap a buffer boundary.
 185          */
 186         if (tail->tail_size < 0 || tail->tail_size > max_bytes) {
 187                 return(3);
 188         }
 189         return(0);
 190 }
 191
 192 static int
 193 hammer_recover_undo(hammer_mount_t hmp, hammer_fifo_undo_t undo, int bytes)
 194 {
 195         hammer_fifo_tail_t tail;
 196         hammer_volume_t volume;
 197         hammer_buffer_t buffer;
 198         int zone;
 199         int error;
 200         int vol_no;
 201         int max_bytes;
 202         u_int32_t offset;
 203
 204         /*
 205          * Basic sanity checks
 206          */
 207         if (bytes < HAMMER_HEAD_ALIGN) {
 208                 kprintf("HAMMER: Undo alignment error (%d)\n", bytes);
 209                 return(EIO);
 210         }
 211         if (undo->head.hdr_signature != HAMMER_HEAD_SIGNATURE) {
 212                 kprintf("HAMMER: Bad head signature %04x\n",
 213                         undo->head.hdr_signature);
 214                 return(EIO);
 215         }
 216         if (undo->head.hdr_size < HAMMER_HEAD_ALIGN ||
 217             undo->head.hdr_size > bytes) {
 218                 kprintf("HAMMER: Bad size %d\n", bytes);
 219                 return(EIO);
 220         }
 221
 222         /*
 223          * Skip PAD records.  Note that PAD records also do not require
 224          * a tail.
 225          */
 226         if (undo->head.hdr_type == HAMMER_HEAD_TYPE_PAD)
 227                 return(0);
 228
 229         /*
 230          * Check the tail
 231          */
 232         bytes = undo->head.hdr_size;
 233         tail = (void *)((char *)undo + bytes - sizeof(*tail));
 234         if (tail->tail_size != undo->head.hdr_size) {
 235                 kprintf("HAMMER: Bad tail size %d\n", tail->tail_size);
 236                 return(EIO);
 237         }
 238         if (tail->tail_type != undo->head.hdr_type) {
 239                 kprintf("HAMMER: Bad tail type %d\n", tail->tail_type);
 240                 return(EIO);
 241         }
 242
 243         /*
 244          * Only process UNDO records
 245          */
 246         if (undo->head.hdr_type != HAMMER_HEAD_TYPE_UNDO)
 247                 return(0);
 248
 249         /*
 250          * Validate the UNDO record.
 251          */
 252         max_bytes = undo->head.hdr_size - sizeof(*undo) - sizeof(*tail);
 253         if (undo->undo_data_bytes < 0 || undo->undo_data_bytes > max_bytes) {
 254                 kprintf("HAMMER: Corrupt UNDO record, undo_data_bytes %d/%d\n",
 255                         undo->undo_data_bytes, max_bytes);
 256                 return(EIO);
 257         }
 258
 259         /*
 260          * The undo offset may only be a zone-1 or zone-2 offset.
 261          *
 262          * Currently we only support a zone-1 offset representing the
 263          * volume header.
 264          */
 265         zone = HAMMER_ZONE_DECODE(undo->undo_offset);
 266         offset = undo->undo_offset & HAMMER_BUFMASK;
 267
 268         if (offset + undo->undo_data_bytes > HAMMER_BUFSIZE) {
 269                 kprintf("HAMMER: Corrupt UNDO record, bad offset\n");
 270                 return (EIO);
 271         }
 272
 273         switch(zone) {
 274         case HAMMER_ZONE_RAW_VOLUME_INDEX:
 275                 vol_no = HAMMER_VOL_DECODE(undo->undo_offset);
 276                 volume = hammer_get_volume(hmp, vol_no, &error);
 277                 if (volume == NULL) {
 278                         kprintf("HAMMER: UNDO record, "
 279                                 "cannot access volume %d\n", vol_no);
 280                         break;
 281                 }
 282                 hammer_modify_volume(NULL, volume, NULL, 0);
 283                 hammer_recover_copy_undo(undo->undo_offset,
 284                                          (char *)(undo + 1),
 285                                          (char *)volume->ondisk + offset,
 286                                          undo->undo_data_bytes);
 287                 hammer_modify_volume_done(volume);
 288                 hammer_io_flush(&volume->io);
 289                 hammer_rel_volume(volume, 0);
 290                 break;
 291         case HAMMER_ZONE_RAW_BUFFER_INDEX:
 292                 buffer = hammer_get_buffer(hmp, undo->undo_offset, 0, &error);
 293                 if (buffer == NULL) {
 294                         kprintf("HAMMER: UNDO record, "
 295                                 "cannot access buffer %016llx\n",
 296                                 undo->undo_offset);
 297                         break;
 298                 }
 299                 hammer_modify_buffer(NULL, buffer, NULL, 0);
 300                 hammer_recover_copy_undo(undo->undo_offset,
 301                                          (char *)(undo + 1),
 302                                          (char *)buffer->ondisk + offset,
 303                                          undo->undo_data_bytes);
 304                 hammer_modify_buffer_done(buffer);
 305                 hammer_io_flush(&buffer->io);
 306                 hammer_rel_buffer(buffer, 0);
 307                 break;
 308         default:
 309                 kprintf("HAMMER: Corrupt UNDO record\n");
 310                 error = EIO;
 311         }
 312         return (error);
 313 }
 314
 315 static void
 316 hammer_recover_copy_undo(hammer_off_t undo_offset,
 317                          char *src, char *dst, int bytes)
 318 {
 319         kprintf("UNDO %016llx: %d\n", undo_offset, bytes);
 320 #if 0
 321         kprintf("UNDO %016llx:", undo_offset);
 322         hammer_recover_debug_dump(22, dst, bytes);
 323         kprintf("%22s", "to:");
 324         hammer_recover_debug_dump(22, src, bytes);
 325 #endif
 326         bcopy(src, dst, bytes);
 327 }
 328
 329 #if 0
 330
 331 static void
 332 hammer_recover_debug_dump(int w, char *buf, int bytes)
 333 {
 334         int i;
 335
 336         for (i = 0; i < bytes; ++i) {
 337                 if (i && (i & 15) == 0)
 338                         kprintf("\n%*.*s", w, w, "");
 339                 kprintf(" %02x", (unsigned char)buf[i]);
 340         }
 341         kprintf("\n");
 342 }
 343
 344 #endif