sys/vfs/hammer/hammer_undo.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_undo.c,v 1.20 2008/07/18 00:19:53 dillon Exp $
  35  */
  36
  37 /*
  38  * HAMMER undo - undo buffer/FIFO management.
  39  */
  40
  41 #include "hammer.h"
  42
  43 static int hammer_und_rb_compare(hammer_undo_t node1, hammer_undo_t node2);
  44
  45 RB_GENERATE2(hammer_und_rb_tree, hammer_undo, rb_node,
  46              hammer_und_rb_compare, hammer_off_t, offset);
  47
  48 /*
  49  * Convert a zone-3 undo offset into a zone-2 buffer offset.
  50  */
  51 hammer_off_t
  52 hammer_undo_lookup(hammer_mount_t hmp, hammer_off_t zone3_off, int *errorp)
  53 {
  54         hammer_volume_t root_volume;
  55         hammer_blockmap_t undomap;
  56         hammer_off_t result_offset;
  57         int i;
  58
  59         KKASSERT((zone3_off & HAMMER_OFF_ZONE_MASK) == HAMMER_ZONE_UNDO);
  60         root_volume = hammer_get_root_volume(hmp, errorp);
  61         if (*errorp)
  62                 return(0);
  63         undomap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX];
  64         KKASSERT(HAMMER_ZONE_DECODE(undomap->alloc_offset) == HAMMER_ZONE_UNDO_INDEX);
  65         KKASSERT (zone3_off < undomap->alloc_offset);
  66
  67         i = (zone3_off & HAMMER_OFF_SHORT_MASK) / HAMMER_LARGEBLOCK_SIZE;
  68         result_offset = root_volume->ondisk->vol0_undo_array[i] +
  69                         (zone3_off & HAMMER_LARGEBLOCK_MASK64);
  70
  71         hammer_rel_volume(root_volume, 0);
  72         return(result_offset);
  73 }
  74
  75 /*
  76  * Generate UNDO record(s) for the block of data at the specified zone1
  77  * or zone2 offset.
  78  *
  79  * The recovery code will execute UNDOs in reverse order, allowing overlaps.
  80  * All the UNDOs are executed together so if we already laid one down we
  81  * do not have to lay another one down for the same range.
  82  *
  83  * For HAMMER version 4+ UNDO a 512 byte boundary is enforced and a PAD
  84  * will be laid down for any unused space.  UNDO FIFO media structures
  85  * will implement the hdr_seq field (it used to be reserved01), and
  86  * both flush and recovery mechanics will be very different.
  87  *
  88  * WARNING!  See also hammer_generate_redo() in hammer_redo.c
  89  */
  90 int
  91 hammer_generate_undo(hammer_transaction_t trans,
  92                      hammer_off_t zone_off, void *base, int len)
  93 {
  94         hammer_mount_t hmp;
  95         hammer_volume_t root_volume;
  96         hammer_blockmap_t undomap;
  97         hammer_buffer_t buffer = NULL;
  98         hammer_fifo_undo_t undo;
  99         hammer_fifo_tail_t tail;
 100         hammer_off_t next_offset;
 101         int error;
 102         int bytes;
 103         int n;
 104
 105         hmp = trans->hmp;
 106
 107         /*
 108          * A SYNC record may be required before we can lay down a general
 109          * UNDO.  This ensures that the nominal recovery span contains
 110          * at least one SYNC record telling the recovery code how far
 111          * out-of-span it must go to run the REDOs.
 112          */
 113         if ((hmp->flags & HAMMER_MOUNT_REDO_SYNC) == 0 &&
 114             hmp->version >= HAMMER_VOL_VERSION_FOUR) {
 115                 hammer_generate_redo_sync(trans);
 116         }
 117
 118         /*
 119          * Enter the offset into our undo history.  If there is an existing
 120          * undo we do not have to generate a new one.
 121          */
 122         if (hammer_enter_undo_history(hmp, zone_off, len) == EALREADY)
 123                 return(0);
 124
 125         root_volume = trans->rootvol;
 126         undomap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX];
 127
 128         /* no undo recursion */
 129         hammer_modify_volume(NULL, root_volume, NULL, 0);
 130         hammer_lock_ex(&hmp->undo_lock);
 131
 132         /* undo had better not roll over (loose test) */
 133         if (hammer_undo_space(trans) < len + HAMMER_BUFSIZE*3)
 134                 panic("hammer: insufficient undo FIFO space!");
 135
 136         /*
 137          * Loop until the undo for the entire range has been laid down.
 138          */
 139         while (len) {
 140                 /*
 141                  * Fetch the layout offset in the UNDO FIFO, wrap it as
 142                  * necessary.
 143                  */
 144                 if (undomap->next_offset == undomap->alloc_offset) {
 145                         undomap->next_offset =
 146                                 HAMMER_ZONE_ENCODE(HAMMER_ZONE_UNDO_INDEX, 0);
 147                 }
 148                 next_offset = undomap->next_offset;
 149
 150                 /*
 151                  * This is a tail-chasing FIFO, when we hit the start of a new
 152                  * buffer we don't have to read it in.
 153                  */
 154                 if ((next_offset & HAMMER_BUFMASK) == 0) {
 155                         undo = hammer_bnew(hmp, next_offset, &error, &buffer);
 156                         hammer_format_undo(undo, hmp->undo_seqno ^ 0x40000000);
 157                 } else {
 158                         undo = hammer_bread(hmp, next_offset, &error, &buffer);
 159                 }
 160                 if (error)
 161                         break;
 162                 hammer_modify_buffer(NULL, buffer, NULL, 0);
 163
 164                 /*
 165                  * Calculate how big a media structure fits up to the next
 166                  * alignment point and how large a data payload we can
 167                  * accomodate.
 168                  *
 169                  * If n calculates to 0 or negative there is no room for
 170                  * anything but a PAD.
 171                  */
 172                 bytes = HAMMER_UNDO_ALIGN -
 173                         ((int)next_offset & HAMMER_UNDO_MASK);
 174                 n = bytes -
 175                     (int)sizeof(struct hammer_fifo_undo) -
 176                     (int)sizeof(struct hammer_fifo_tail);
 177
 178                 /*
 179                  * If available space is insufficient for any payload
 180                  * we have to lay down a PAD.
 181                  *
 182                  * The minimum PAD is 8 bytes and the head and tail will
 183                  * overlap each other in that case.  PADs do not have
 184                  * sequence numbers or CRCs.
 185                  *
 186                  * A PAD may not start on a boundary.  That is, every
 187                  * 512-byte block in the UNDO/REDO FIFO must begin with
 188                  * a record containing a sequence number.
 189                  */
 190                 if (n <= 0) {
 191                         KKASSERT(bytes >= sizeof(struct hammer_fifo_tail));
 192                         KKASSERT(((int)next_offset & HAMMER_UNDO_MASK) != 0);
 193                         tail = (void *)((char *)undo + bytes - sizeof(*tail));
 194                         if ((void *)undo != (void *)tail) {
 195                                 tail->tail_signature = HAMMER_TAIL_SIGNATURE;
 196                                 tail->tail_type = HAMMER_HEAD_TYPE_PAD;
 197                                 tail->tail_size = bytes;
 198                         }
 199                         undo->head.hdr_signature = HAMMER_HEAD_SIGNATURE;
 200                         undo->head.hdr_type = HAMMER_HEAD_TYPE_PAD;
 201                         undo->head.hdr_size = bytes;
 202                         /* NO CRC OR SEQ NO */
 203                         undomap->next_offset += bytes;
 204                         hammer_modify_buffer_done(buffer);
 205                         hammer_stats_undo += bytes;
 206                         continue;
 207                 }
 208
 209                 /*
 210                  * Calculate the actual payload and recalculate the size
 211                  * of the media structure as necessary.
 212                  */
 213                 if (n > len) {
 214                         n = len;
 215                         bytes = ((n + HAMMER_HEAD_ALIGN_MASK) &
 216                                  ~HAMMER_HEAD_ALIGN_MASK) +
 217                                 (int)sizeof(struct hammer_fifo_undo) +
 218                                 (int)sizeof(struct hammer_fifo_tail);
 219                 }
 220                 if (hammer_debug_general & 0x0080) {
 221                         kprintf("undo %016llx %d %d\n",
 222                                 (long long)next_offset, bytes, n);
 223                 }
 224
 225                 undo->head.hdr_signature = HAMMER_HEAD_SIGNATURE;
 226                 undo->head.hdr_type = HAMMER_HEAD_TYPE_UNDO;
 227                 undo->head.hdr_size = bytes;
 228                 undo->head.hdr_seq = hmp->undo_seqno++;
 229                 undo->head.hdr_crc = 0;
 230                 undo->undo_offset = zone_off;
 231                 undo->undo_data_bytes = n;
 232                 bcopy(base, undo + 1, n);
 233
 234                 tail = (void *)((char *)undo + bytes - sizeof(*tail));
 235                 tail->tail_signature = HAMMER_TAIL_SIGNATURE;
 236                 tail->tail_type = HAMMER_HEAD_TYPE_UNDO;
 237                 tail->tail_size = bytes;
 238
 239                 KKASSERT(bytes >= sizeof(undo->head));
 240                 undo->head.hdr_crc = crc32(undo, HAMMER_FIFO_HEAD_CRCOFF) ^
 241                              crc32(&undo->head + 1, bytes - sizeof(undo->head));
 242                 undomap->next_offset += bytes;
 243                 hammer_stats_undo += bytes;
 244
 245                 /*
 246                  * Before we finish off the buffer we have to deal with any
 247                  * junk between the end of the media structure we just laid
 248                  * down and the UNDO alignment boundary.  We do this by laying
 249                  * down a dummy PAD.  Even though we will probably overwrite
 250                  * it almost immediately we have to do this so recovery runs
 251                  * can iterate the UNDO space without having to depend on
 252                  * the indices in the volume header.
 253                  *
 254                  * This dummy PAD will be overwritten on the next undo so
 255                  * we do not adjust undomap->next_offset.
 256                  */
 257                 bytes = HAMMER_UNDO_ALIGN -
 258                         ((int)undomap->next_offset & HAMMER_UNDO_MASK);
 259                 if (bytes != HAMMER_UNDO_ALIGN) {
 260                         KKASSERT(bytes >= sizeof(struct hammer_fifo_tail));
 261                         undo = (void *)(tail + 1);
 262                         tail = (void *)((char *)undo + bytes - sizeof(*tail));
 263                         if ((void *)undo != (void *)tail) {
 264                                 tail->tail_signature = HAMMER_TAIL_SIGNATURE;
 265                                 tail->tail_type = HAMMER_HEAD_TYPE_PAD;
 266                                 tail->tail_size = bytes;
 267                         }
 268                         undo->head.hdr_signature = HAMMER_HEAD_SIGNATURE;
 269                         undo->head.hdr_type = HAMMER_HEAD_TYPE_PAD;
 270                         undo->head.hdr_size = bytes;
 271                         /* NO CRC OR SEQ NO */
 272                 }
 273                 hammer_modify_buffer_done(buffer);
 274
 275                 /*
 276                  * Adjust for loop
 277                  */
 278                 len -= n;
 279                 base = (char *)base + n;
 280                 zone_off += n;
 281         }
 282         hammer_modify_volume_done(root_volume);
 283         hammer_unlock(&hmp->undo_lock);
 284
 285         if (buffer)
 286                 hammer_rel_buffer(buffer, 0);
 287         return(error);
 288 }
 289
 290 /*
 291  * Preformat a new UNDO block.  We could read the old one in but we get
 292  * better performance if we just pre-format a new one.
 293  *
 294  * The recovery code always works forwards so the caller just makes sure the
 295  * seqno is not contiguous with prior UNDOs or ancient UNDOs now being
 296  * overwritten.
 297  *
 298  * The preformatted UNDO headers use the smallest possible sector size
 299  * (512) to ensure that any missed media writes are caught.
 300  *
 301  * NOTE: Also used by the REDO code.
 302  */
 303 void
 304 hammer_format_undo(void *base, u_int32_t seqno)
 305 {
 306         hammer_fifo_head_t head;
 307         hammer_fifo_tail_t tail;
 308         int i;
 309         int bytes = HAMMER_UNDO_ALIGN;
 310
 311         bzero(base, HAMMER_BUFSIZE);
 312
 313         for (i = 0; i < HAMMER_BUFSIZE; i += bytes) {
 314                 head = (void *)((char *)base + i);
 315                 tail = (void *)((char *)head + bytes - sizeof(*tail));
 316
 317                 head->hdr_signature = HAMMER_HEAD_SIGNATURE;
 318                 head->hdr_type = HAMMER_HEAD_TYPE_DUMMY;
 319                 head->hdr_size = bytes;
 320                 head->hdr_seq = seqno++;
 321                 head->hdr_crc = 0;
 322
 323                 tail->tail_signature = HAMMER_TAIL_SIGNATURE;
 324                 tail->tail_type = HAMMER_HEAD_TYPE_DUMMY;
 325                 tail->tail_size = bytes;
 326
 327                 head->hdr_crc = crc32(head, HAMMER_FIFO_HEAD_CRCOFF) ^
 328                              crc32(head + 1, bytes - sizeof(*head));
 329         }
 330 }
 331
 332 /*
 333  * HAMMER version 4+ conversion support.
 334  *
 335  * Convert a HAMMER version < 4 UNDO FIFO area to a 4+ UNDO FIFO area.
 336  * The 4+ UNDO FIFO area is backwards compatible.  The conversion is
 337  * needed to initialize the sequence space and place headers on the
 338  * new 512-byte undo boundary.
 339  */
 340 int
 341 hammer_upgrade_undo_4(hammer_transaction_t trans)
 342 {
 343         hammer_mount_t hmp;
 344         hammer_volume_t root_volume;
 345         hammer_blockmap_t undomap;
 346         hammer_buffer_t buffer = NULL;
 347         hammer_fifo_head_t head;
 348         hammer_fifo_tail_t tail;
 349         hammer_off_t next_offset;
 350         u_int32_t seqno;
 351         int error;
 352         int bytes;
 353
 354         hmp = trans->hmp;
 355
 356         root_volume = trans->rootvol;
 357
 358         /* no undo recursion */
 359         hammer_lock_ex(&hmp->undo_lock);
 360         hammer_modify_volume(NULL, root_volume, NULL, 0);
 361
 362         /*
 363          * Adjust the in-core undomap and the on-disk undomap.
 364          */
 365         next_offset = HAMMER_ZONE_ENCODE(HAMMER_ZONE_UNDO_INDEX, 0);
 366         undomap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX];
 367         undomap->next_offset = next_offset;
 368         undomap->first_offset = next_offset;
 369
 370         undomap = &root_volume->ondisk->vol0_blockmap[HAMMER_ZONE_UNDO_INDEX];
 371         undomap->next_offset = next_offset;
 372         undomap->first_offset = next_offset;
 373
 374         /*
 375          * Loop over the entire UNDO space creating DUMMY entries.  Sequence
 376          * numbers are assigned.
 377          */
 378         seqno = 0;
 379         bytes = HAMMER_UNDO_ALIGN;
 380
 381         while (next_offset != undomap->alloc_offset) {
 382                 head = hammer_bnew(hmp, next_offset, &error, &buffer);
 383                 if (error)
 384                         break;
 385                 hammer_modify_buffer(NULL, buffer, NULL, 0);
 386                 tail = (void *)((char *)head + bytes - sizeof(*tail));
 387
 388                 head->hdr_signature = HAMMER_HEAD_SIGNATURE;
 389                 head->hdr_type = HAMMER_HEAD_TYPE_DUMMY;
 390                 head->hdr_size = bytes;
 391                 head->hdr_seq = seqno;
 392                 head->hdr_crc = 0;
 393
 394                 tail = (void *)((char *)head + bytes - sizeof(*tail));
 395                 tail->tail_signature = HAMMER_TAIL_SIGNATURE;
 396                 tail->tail_type = HAMMER_HEAD_TYPE_DUMMY;
 397                 tail->tail_size = bytes;
 398
 399                 head->hdr_crc = crc32(head, HAMMER_FIFO_HEAD_CRCOFF) ^
 400                              crc32(head + 1, bytes - sizeof(*head));
 401                 hammer_modify_buffer_done(buffer);
 402
 403                 hammer_stats_undo += bytes;
 404                 next_offset += HAMMER_UNDO_ALIGN;
 405                 ++seqno;
 406         }
 407
 408         /*
 409          * The sequence number will be the next sequence number to lay down.
 410          */
 411         hmp->undo_seqno = seqno;
 412         kprintf("version upgrade seqno start %08x\n", seqno);
 413
 414         hammer_modify_volume_done(root_volume);
 415         hammer_unlock(&hmp->undo_lock);
 416
 417         if (buffer)
 418                 hammer_rel_buffer(buffer, 0);
 419         return (error);
 420 }
 421
 422 /*
 423  * UNDO HISTORY API
 424  *
 425  * It is not necessary to layout an undo record for the same address space
 426  * multiple times.  Maintain a cache of recent undo's.
 427  */
 428
 429 /*
 430  * Enter an undo into the history.  Return EALREADY if the request completely
 431  * covers a previous request.
 432  */
 433 int
 434 hammer_enter_undo_history(hammer_mount_t hmp, hammer_off_t offset, int bytes)
 435 {
 436         hammer_undo_t node;
 437         hammer_undo_t onode;
 438
 439         node = RB_LOOKUP(hammer_und_rb_tree, &hmp->rb_undo_root, offset);
 440         if (node) {
 441                 TAILQ_REMOVE(&hmp->undo_lru_list, node, lru_entry);
 442                 TAILQ_INSERT_TAIL(&hmp->undo_lru_list, node, lru_entry);
 443                 if (bytes <= node->bytes)
 444                         return(EALREADY);
 445                 node->bytes = bytes;
 446                 return(0);
 447         }
 448         if (hmp->undo_alloc != HAMMER_MAX_UNDOS) {
 449                 node = &hmp->undos[hmp->undo_alloc++];
 450         } else {
 451                 node = TAILQ_FIRST(&hmp->undo_lru_list);
 452                 TAILQ_REMOVE(&hmp->undo_lru_list, node, lru_entry);
 453                 RB_REMOVE(hammer_und_rb_tree, &hmp->rb_undo_root, node);
 454         }
 455         node->offset = offset;
 456         node->bytes = bytes;
 457         TAILQ_INSERT_TAIL(&hmp->undo_lru_list, node, lru_entry);
 458         onode = RB_INSERT(hammer_und_rb_tree, &hmp->rb_undo_root, node);
 459         KKASSERT(onode == NULL);
 460         return(0);
 461 }
 462
 463 void
 464 hammer_clear_undo_history(hammer_mount_t hmp)
 465 {
 466         RB_INIT(&hmp->rb_undo_root);
 467         TAILQ_INIT(&hmp->undo_lru_list);
 468         hmp->undo_alloc = 0;
 469 }
 470
 471 /*
 472  * Return how much of the undo FIFO has been used
 473  *
 474  * The calculation includes undo FIFO space still reserved from a previous
 475  * flush (because it will still be run on recovery if a crash occurs and
 476  * we can't overwrite it yet).
 477  */
 478 int64_t
 479 hammer_undo_used(hammer_transaction_t trans)
 480 {
 481         hammer_blockmap_t cundomap;
 482         hammer_blockmap_t dundomap;
 483         int64_t max_bytes;
 484         int64_t bytes;
 485
 486         cundomap = &trans->hmp->blockmap[HAMMER_ZONE_UNDO_INDEX];
 487         dundomap = &trans->rootvol->ondisk->
 488                                 vol0_blockmap[HAMMER_ZONE_UNDO_INDEX];
 489
 490         if (dundomap->first_offset <= cundomap->next_offset) {
 491                 bytes = cundomap->next_offset - dundomap->first_offset;
 492         } else {
 493                 bytes = cundomap->alloc_offset - dundomap->first_offset +
 494                         (cundomap->next_offset & HAMMER_OFF_LONG_MASK);
 495         }
 496         max_bytes = cundomap->alloc_offset & HAMMER_OFF_SHORT_MASK;
 497         KKASSERT(bytes <= max_bytes);
 498         return(bytes);
 499 }
 500
 501 /*
 502  * Return how much of the undo FIFO is available for new records.
 503  */
 504 int64_t
 505 hammer_undo_space(hammer_transaction_t trans)
 506 {
 507         hammer_blockmap_t rootmap;
 508         int64_t max_bytes;
 509
 510         rootmap = &trans->hmp->blockmap[HAMMER_ZONE_UNDO_INDEX];
 511         max_bytes = rootmap->alloc_offset & HAMMER_OFF_SHORT_MASK;
 512         return(max_bytes - hammer_undo_used(trans));
 513 }
 514
 515 int64_t
 516 hammer_undo_max(hammer_mount_t hmp)
 517 {
 518         hammer_blockmap_t rootmap;
 519         int64_t max_bytes;
 520
 521         rootmap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX];
 522         max_bytes = rootmap->alloc_offset & HAMMER_OFF_SHORT_MASK;
 523
 524         return(max_bytes);
 525 }
 526
 527 /*
 528  * Returns 1 if the undo buffer should be reclaimed on release.  The
 529  * only undo buffer we do NOT want to reclaim is the one at the current
 530  * append offset.
 531  */
 532 int
 533 hammer_undo_reclaim(hammer_io_t io)
 534 {
 535         hammer_blockmap_t undomap;
 536         hammer_off_t next_offset;
 537
 538         undomap = &io->hmp->blockmap[HAMMER_ZONE_UNDO_INDEX];
 539         next_offset = undomap->next_offset & ~HAMMER_BUFMASK64;
 540         if (((struct hammer_buffer *)io)->zoneX_offset == next_offset)
 541                 return(0);
 542         return(1);
 543 }
 544
 545 static int
 546 hammer_und_rb_compare(hammer_undo_t node1, hammer_undo_t node2)
 547 {
 548         if (node1->offset < node2->offset)
 549                 return(-1);
 550         if (node1->offset > node2->offset)
 551                 return(1);
 552         return(0);
 553 }
 554