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 35 /* 36 * HAMMER undo - undo buffer/FIFO management. 37 */ 38 39 #include "hammer.h" 40 41 static int 42 hammer_und_rb_compare(hammer_undo_t node1, hammer_undo_t node2) 43 { 44 if (node1->offset < node2->offset) 45 return(-1); 46 if (node1->offset > node2->offset) 47 return(1); 48 return(0); 49 } 50 51 RB_GENERATE2(hammer_und_rb_tree, hammer_undo, rb_node, 52 hammer_und_rb_compare, hammer_off_t, offset); 53 54 /* 55 * Convert a zone-3 undo offset into a zone-2 buffer offset. 56 */ 57 hammer_off_t 58 hammer_undo_lookup(hammer_mount_t hmp, hammer_off_t zone3_off, int *errorp) 59 { 60 hammer_volume_t root_volume; 61 hammer_blockmap_t undomap __debugvar; 62 hammer_off_t result_offset; 63 64 KKASSERT(hammer_is_zone_undo(zone3_off)); 65 root_volume = hammer_get_root_volume(hmp, errorp); 66 if (*errorp) 67 return(0); 68 undomap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 69 KKASSERT(hammer_is_zone_undo(undomap->alloc_offset)); 70 KKASSERT(zone3_off < undomap->alloc_offset); 71 72 result_offset = hammer_xlate_to_undo(root_volume->ondisk, zone3_off); 73 74 hammer_rel_volume(root_volume, 0); 75 return(result_offset); 76 } 77 78 /* 79 * Generate UNDO record(s) for the block of data at the specified zone1 80 * or zone2 offset. 81 * 82 * The recovery code will execute UNDOs in reverse order, allowing overlaps. 83 * All the UNDOs are executed together so if we already laid one down we 84 * do not have to lay another one down for the same range. 85 * 86 * For HAMMER version 4+ UNDO a 512 byte boundary is enforced and a PAD 87 * will be laid down for any unused space. UNDO FIFO media structures 88 * will implement the hdr_seq field (it used to be reserved01), and 89 * both flush and recovery mechanics will be very different. 90 * 91 * WARNING! See also hammer_generate_redo() in hammer_redo.c 92 */ 93 int 94 hammer_generate_undo(hammer_transaction_t trans, 95 hammer_off_t zone_off, void *base, int len) 96 { 97 hammer_mount_t hmp; 98 hammer_volume_t root_volume; 99 hammer_blockmap_t undomap; 100 hammer_buffer_t buffer = NULL; 101 hammer_fifo_undo_t undo; 102 hammer_fifo_tail_t tail; 103 hammer_off_t next_offset; 104 int error; 105 int bytes; 106 int n; 107 108 hmp = trans->hmp; 109 110 /* 111 * A SYNC record may be required before we can lay down a general 112 * UNDO. This ensures that the nominal recovery span contains 113 * at least one SYNC record telling the recovery code how far 114 * out-of-span it must go to run the REDOs. 115 */ 116 if ((hmp->flags & HAMMER_MOUNT_REDO_SYNC) == 0 && 117 hmp->version >= HAMMER_VOL_VERSION_FOUR) { 118 hammer_generate_redo_sync(trans); 119 } 120 121 /* 122 * Enter the offset into our undo history. If there is an existing 123 * undo we do not have to generate a new one. 124 */ 125 if (hammer_enter_undo_history(hmp, zone_off, len) == EALREADY) 126 return(0); 127 128 root_volume = trans->rootvol; 129 undomap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 130 131 /* no undo recursion */ 132 hammer_modify_volume_noundo(NULL, root_volume); 133 hammer_lock_ex(&hmp->undo_lock); 134 135 /* undo had better not roll over (loose test) */ 136 if (hammer_undo_space(trans) < len + HAMMER_BUFSIZE*3) 137 hpanic("insufficient UNDO/REDO FIFO space for undo!"); 138 139 /* 140 * Loop until the undo for the entire range has been laid down. 141 */ 142 while (len) { 143 /* 144 * Fetch the layout offset in the UNDO FIFO, wrap it as 145 * necessary. 146 */ 147 if (undomap->next_offset == undomap->alloc_offset) 148 undomap->next_offset = HAMMER_ENCODE_UNDO(0); 149 next_offset = undomap->next_offset; 150 151 /* 152 * This is a tail-chasing FIFO, when we hit the start of a new 153 * buffer we don't have to read it in. 154 */ 155 if ((next_offset & HAMMER_BUFMASK) == 0) { 156 undo = hammer_bnew(hmp, next_offset, &error, &buffer); 157 hammer_format_undo(hmp, undo, 158 hmp->undo_seqno ^ 0x40000000); 159 } else { 160 undo = hammer_bread(hmp, next_offset, &error, &buffer); 161 } 162 if (error) 163 break; 164 /* no undo recursion */ 165 hammer_modify_buffer_noundo(NULL, buffer); 166 167 /* 168 * Calculate how big a media structure fits up to the next 169 * alignment point and how large a data payload we can 170 * accomodate. 171 * 172 * If n calculates to 0 or negative there is no room for 173 * anything but a PAD. 174 */ 175 bytes = HAMMER_UNDO_ALIGN - 176 ((int)next_offset & HAMMER_UNDO_MASK); 177 n = bytes - 178 (int)sizeof(struct hammer_fifo_undo) - 179 (int)sizeof(struct hammer_fifo_tail); 180 181 /* 182 * If available space is insufficient for any payload 183 * we have to lay down a PAD. 184 * 185 * The minimum PAD is 8 bytes and the head and tail will 186 * overlap each other in that case. PADs do not have 187 * sequence numbers or CRCs. 188 * 189 * A PAD may not start on a boundary. That is, every 190 * 512-byte block in the UNDO/REDO FIFO must begin with 191 * a record containing a sequence number. 192 */ 193 if (n <= 0) { 194 KKASSERT(bytes >= sizeof(struct hammer_fifo_tail)); 195 KKASSERT(((int)next_offset & HAMMER_UNDO_MASK) != 0); 196 tail = (void *)((char *)undo + bytes - sizeof(*tail)); 197 if ((void *)undo != (void *)tail) { 198 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 199 tail->tail_type = HAMMER_HEAD_TYPE_PAD; 200 tail->tail_size = bytes; 201 } 202 undo->head.hdr_signature = HAMMER_HEAD_SIGNATURE; 203 undo->head.hdr_type = HAMMER_HEAD_TYPE_PAD; 204 undo->head.hdr_size = bytes; 205 /* NO CRC OR SEQ NO */ 206 undomap->next_offset += bytes; 207 hammer_modify_buffer_done(buffer); 208 hammer_stats_undo += bytes; 209 continue; 210 } 211 212 /* 213 * Calculate the actual payload and recalculate the size 214 * of the media structure as necessary. 215 */ 216 if (n > len) { 217 n = len; 218 bytes = HAMMER_HEAD_DOALIGN(n) + 219 (int)sizeof(struct hammer_fifo_undo) + 220 (int)sizeof(struct hammer_fifo_tail); 221 } 222 if (hammer_debug_general & 0x0080) { 223 hdkprintf("undo %016jx %d %d\n", 224 (intmax_t)next_offset, bytes, n); 225 } 226 227 undo->head.hdr_signature = HAMMER_HEAD_SIGNATURE; 228 undo->head.hdr_type = HAMMER_HEAD_TYPE_UNDO; 229 undo->head.hdr_size = bytes; 230 undo->head.hdr_seq = hmp->undo_seqno++; 231 undo->head.hdr_crc = 0; 232 undo->undo_offset = zone_off; 233 undo->undo_data_bytes = n; 234 bcopy(base, undo + 1, n); 235 236 tail = (void *)((char *)undo + bytes - sizeof(*tail)); 237 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 238 tail->tail_type = HAMMER_HEAD_TYPE_UNDO; 239 tail->tail_size = bytes; 240 241 KKASSERT(bytes >= sizeof(undo->head)); 242 hammer_crc_set_fifo_head(hmp->version, &undo->head, bytes); 243 undomap->next_offset += bytes; 244 hammer_stats_undo += bytes; 245 246 /* 247 * Before we finish off the buffer we have to deal with any 248 * junk between the end of the media structure we just laid 249 * down and the UNDO alignment boundary. We do this by laying 250 * down a dummy PAD. Even though we will probably overwrite 251 * it almost immediately we have to do this so recovery runs 252 * can iterate the UNDO space without having to depend on 253 * the indices in the volume header. 254 * 255 * This dummy PAD will be overwritten on the next undo so 256 * we do not adjust undomap->next_offset. 257 */ 258 bytes = HAMMER_UNDO_ALIGN - 259 ((int)undomap->next_offset & HAMMER_UNDO_MASK); 260 if (bytes != HAMMER_UNDO_ALIGN) { 261 KKASSERT(bytes >= sizeof(struct hammer_fifo_tail)); 262 undo = (void *)(tail + 1); 263 tail = (void *)((char *)undo + bytes - sizeof(*tail)); 264 if ((void *)undo != (void *)tail) { 265 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 266 tail->tail_type = HAMMER_HEAD_TYPE_PAD; 267 tail->tail_size = bytes; 268 } 269 undo->head.hdr_signature = HAMMER_HEAD_SIGNATURE; 270 undo->head.hdr_type = HAMMER_HEAD_TYPE_PAD; 271 undo->head.hdr_size = bytes; 272 /* NO CRC OR SEQ NO */ 273 } 274 hammer_modify_buffer_done(buffer); 275 276 /* 277 * Adjust for loop 278 */ 279 len -= n; 280 base = (char *)base + n; 281 zone_off += n; 282 } 283 hammer_modify_volume_done(root_volume); 284 hammer_unlock(&hmp->undo_lock); 285 286 if (buffer) 287 hammer_rel_buffer(buffer, 0); 288 return(error); 289 } 290 291 /* 292 * Preformat a new UNDO block. We could read the old one in but we get 293 * better performance if we just pre-format a new one. 294 * 295 * The recovery code always works forwards so the caller just makes sure the 296 * seqno is not contiguous with prior UNDOs or ancient UNDOs now being 297 * overwritten. 298 * 299 * The preformatted UNDO headers use the smallest possible sector size 300 * (512) to ensure that any missed media writes are caught. 301 * 302 * NOTE: Also used by the REDO code. 303 */ 304 void 305 hammer_format_undo(hammer_mount_t hmp, void *base, uint32_t seqno) 306 { 307 hammer_fifo_head_t head; 308 hammer_fifo_tail_t tail; 309 int i; 310 int bytes = HAMMER_UNDO_ALIGN; 311 312 bzero(base, HAMMER_BUFSIZE); 313 314 for (i = 0; i < HAMMER_BUFSIZE; i += bytes) { 315 head = (void *)((char *)base + i); 316 tail = (void *)((char *)head + bytes - sizeof(*tail)); 317 318 head->hdr_signature = HAMMER_HEAD_SIGNATURE; 319 head->hdr_type = HAMMER_HEAD_TYPE_DUMMY; 320 head->hdr_size = bytes; 321 head->hdr_seq = seqno++; 322 head->hdr_crc = 0; 323 324 tail->tail_signature = HAMMER_TAIL_SIGNATURE; 325 tail->tail_type = HAMMER_HEAD_TYPE_DUMMY; 326 tail->tail_size = bytes; 327 328 hammer_crc_set_fifo_head(hmp->version, head, bytes); 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 uint32_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_noundo(NULL, root_volume); 361 362 /* 363 * Adjust the in-core undomap and the on-disk undomap. 364 */ 365 next_offset = HAMMER_ENCODE_UNDO(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_noundo(NULL, buffer); 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 hammer_crc_set_fifo_head(hmp->version, head, bytes); 400 hammer_modify_buffer_done(buffer); 401 402 hammer_stats_undo += bytes; 403 next_offset += HAMMER_UNDO_ALIGN; 404 ++seqno; 405 } 406 407 /* 408 * The sequence number will be the next sequence number to lay down. 409 */ 410 hmp->undo_seqno = seqno; 411 hmkprintf(hmp, "version upgrade seqno start %08x\n", seqno); 412 413 hammer_modify_volume_done(root_volume); 414 hammer_unlock(&hmp->undo_lock); 415 416 if (buffer) 417 hammer_rel_buffer(buffer, 0); 418 return (error); 419 } 420 421 /* 422 * UNDO HISTORY API 423 * 424 * It is not necessary to layout an undo record for the same address space 425 * multiple times. Maintain a cache of recent undo's. 426 */ 427 428 /* 429 * Enter an undo into the history. Return EALREADY if the request completely 430 * covers a previous request. 431 */ 432 int 433 hammer_enter_undo_history(hammer_mount_t hmp, hammer_off_t offset, int bytes) 434 { 435 hammer_undo_t node; 436 hammer_undo_t onode __debugvar; 437 438 node = RB_LOOKUP(hammer_und_rb_tree, &hmp->rb_undo_root, offset); 439 if (node) { 440 TAILQ_REMOVE(&hmp->undo_lru_list, node, lru_entry); 441 TAILQ_INSERT_TAIL(&hmp->undo_lru_list, node, lru_entry); 442 if (bytes <= node->bytes) 443 return(EALREADY); 444 node->bytes = bytes; 445 return(0); 446 } 447 if (hmp->undo_alloc != HAMMER_MAX_UNDOS) { 448 node = &hmp->undos[hmp->undo_alloc++]; 449 } else { 450 node = TAILQ_FIRST(&hmp->undo_lru_list); 451 TAILQ_REMOVE(&hmp->undo_lru_list, node, lru_entry); 452 RB_REMOVE(hammer_und_rb_tree, &hmp->rb_undo_root, node); 453 } 454 node->offset = offset; 455 node->bytes = bytes; 456 TAILQ_INSERT_TAIL(&hmp->undo_lru_list, node, lru_entry); 457 onode = RB_INSERT(hammer_und_rb_tree, &hmp->rb_undo_root, node); 458 KKASSERT(onode == NULL); 459 return(0); 460 } 461 462 void 463 hammer_clear_undo_history(hammer_mount_t hmp) 464 { 465 RB_INIT(&hmp->rb_undo_root); 466 TAILQ_INIT(&hmp->undo_lru_list); 467 hmp->undo_alloc = 0; 468 } 469 470 /* 471 * Return how much of the undo FIFO has been used 472 * 473 * The calculation includes undo FIFO space still reserved from a previous 474 * flush (because it will still be run on recovery if a crash occurs and 475 * we can't overwrite it yet). 476 */ 477 int64_t 478 hammer_undo_used(hammer_transaction_t trans) 479 { 480 hammer_blockmap_t cundomap; 481 hammer_blockmap_t dundomap; 482 int64_t max_bytes __debugvar; 483 int64_t bytes; 484 485 cundomap = &trans->hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 486 dundomap = &trans->rootvol->ondisk-> 487 vol0_blockmap[HAMMER_ZONE_UNDO_INDEX]; 488 489 if (dundomap->first_offset <= cundomap->next_offset) { 490 bytes = cundomap->next_offset - dundomap->first_offset; 491 } else { 492 bytes = cundomap->alloc_offset - dundomap->first_offset + 493 HAMMER_OFF_LONG_ENCODE(cundomap->next_offset); 494 } 495 max_bytes = HAMMER_OFF_SHORT_ENCODE(cundomap->alloc_offset); 496 KKASSERT(bytes <= max_bytes); 497 return(bytes); 498 } 499 500 /* 501 * Return how much of the undo FIFO is available for new records. 502 */ 503 int64_t 504 hammer_undo_space(hammer_transaction_t trans) 505 { 506 hammer_blockmap_t rootmap; 507 int64_t max_bytes; 508 509 rootmap = &trans->hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 510 max_bytes = HAMMER_OFF_SHORT_ENCODE(rootmap->alloc_offset); 511 return(max_bytes - hammer_undo_used(trans)); 512 } 513 514 int64_t 515 hammer_undo_max(hammer_mount_t hmp) 516 { 517 hammer_blockmap_t rootmap; 518 int64_t max_bytes; 519 520 rootmap = &hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 521 max_bytes = HAMMER_OFF_SHORT_ENCODE(rootmap->alloc_offset); 522 523 return(max_bytes); 524 } 525 526 /* 527 * Returns 1 if the undo buffer should be reclaimed on release. The 528 * only undo buffer we do NOT want to reclaim is the one at the current 529 * append offset. 530 */ 531 int 532 hammer_undo_reclaim(hammer_io_t io) 533 { 534 hammer_blockmap_t undomap; 535 hammer_off_t next_offset; 536 537 undomap = &io->hmp->blockmap[HAMMER_ZONE_UNDO_INDEX]; 538 next_offset = undomap->next_offset & ~HAMMER_BUFMASK64; 539 if (HAMMER_ITOB(io)->zoneX_offset == next_offset) 540 return(0); 541 return(1); 542 } 543