1 /* 2 * Copyright (C) 2003 Sistina Software Limited. 3 * Copyright (C) 2005-2008 Red Hat, Inc. All rights reserved. 4 * 5 * This file is released under the GPL. 6 */ 7 8 #include "dm-bio-record.h" 9 10 #include <linux/init.h> 11 #include <linux/mempool.h> 12 #include <linux/module.h> 13 #include <linux/pagemap.h> 14 #include <linux/slab.h> 15 #include <linux/workqueue.h> 16 #include <linux/device-mapper.h> 17 #include <linux/dm-io.h> 18 #include <linux/dm-dirty-log.h> 19 #include <linux/dm-kcopyd.h> 20 #include <linux/dm-region-hash.h> 21 22 #define DM_MSG_PREFIX "raid1" 23 24 #define MAX_RECOVERY 1 /* Maximum number of regions recovered in parallel. */ 25 26 #define DM_RAID1_HANDLE_ERRORS 0x01 27 #define DM_RAID1_KEEP_LOG 0x02 28 #define errors_handled(p) ((p)->features & DM_RAID1_HANDLE_ERRORS) 29 #define keep_log(p) ((p)->features & DM_RAID1_KEEP_LOG) 30 31 static DECLARE_WAIT_QUEUE_HEAD(_kmirrord_recovery_stopped); 32 33 /*----------------------------------------------------------------- 34 * Mirror set structures. 35 *---------------------------------------------------------------*/ 36 enum dm_raid1_error { 37 DM_RAID1_WRITE_ERROR, 38 DM_RAID1_FLUSH_ERROR, 39 DM_RAID1_SYNC_ERROR, 40 DM_RAID1_READ_ERROR 41 }; 42 43 struct mirror { 44 struct mirror_set *ms; 45 atomic_t error_count; 46 unsigned long error_type; 47 struct dm_dev *dev; 48 sector_t offset; 49 }; 50 51 struct mirror_set { 52 struct dm_target *ti; 53 struct list_head list; 54 55 uint64_t features; 56 57 spinlock_t lock; /* protects the lists */ 58 struct bio_list reads; 59 struct bio_list writes; 60 struct bio_list failures; 61 struct bio_list holds; /* bios are waiting until suspend */ 62 63 struct dm_region_hash *rh; 64 struct dm_kcopyd_client *kcopyd_client; 65 struct dm_io_client *io_client; 66 67 /* recovery */ 68 region_t nr_regions; 69 int in_sync; 70 int log_failure; 71 int leg_failure; 72 atomic_t suspend; 73 74 atomic_t default_mirror; /* Default mirror */ 75 76 struct workqueue_struct *kmirrord_wq; 77 struct work_struct kmirrord_work; 78 struct timer_list timer; 79 unsigned long timer_pending; 80 81 struct work_struct trigger_event; 82 83 unsigned nr_mirrors; 84 struct mirror mirror[0]; 85 }; 86 87 DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(raid1_resync_throttle, 88 "A percentage of time allocated for raid resynchronization"); 89 90 static void wakeup_mirrord(void *context) 91 { 92 struct mirror_set *ms = context; 93 94 queue_work(ms->kmirrord_wq, &ms->kmirrord_work); 95 } 96 97 static void delayed_wake_fn(unsigned long data) 98 { 99 struct mirror_set *ms = (struct mirror_set *) data; 100 101 clear_bit(0, &ms->timer_pending); 102 wakeup_mirrord(ms); 103 } 104 105 static void delayed_wake(struct mirror_set *ms) 106 { 107 if (test_and_set_bit(0, &ms->timer_pending)) 108 return; 109 110 ms->timer.expires = jiffies + HZ / 5; 111 ms->timer.data = (unsigned long) ms; 112 ms->timer.function = delayed_wake_fn; 113 add_timer(&ms->timer); 114 } 115 116 static void wakeup_all_recovery_waiters(void *context) 117 { 118 wake_up_all(&_kmirrord_recovery_stopped); 119 } 120 121 static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw) 122 { 123 unsigned long flags; 124 int should_wake = 0; 125 struct bio_list *bl; 126 127 bl = (rw == WRITE) ? &ms->writes : &ms->reads; 128 spin_lock_irqsave(&ms->lock, flags); 129 should_wake = !(bl->head); 130 bio_list_add(bl, bio); 131 spin_unlock_irqrestore(&ms->lock, flags); 132 133 if (should_wake) 134 wakeup_mirrord(ms); 135 } 136 137 static void dispatch_bios(void *context, struct bio_list *bio_list) 138 { 139 struct mirror_set *ms = context; 140 struct bio *bio; 141 142 while ((bio = bio_list_pop(bio_list))) 143 queue_bio(ms, bio, WRITE); 144 } 145 146 struct dm_raid1_bio_record { 147 struct mirror *m; 148 /* if details->bi_bdev == NULL, details were not saved */ 149 struct dm_bio_details details; 150 region_t write_region; 151 }; 152 153 /* 154 * Every mirror should look like this one. 155 */ 156 #define DEFAULT_MIRROR 0 157 158 /* 159 * This is yucky. We squirrel the mirror struct away inside 160 * bi_next for read/write buffers. This is safe since the bh 161 * doesn't get submitted to the lower levels of block layer. 162 */ 163 static struct mirror *bio_get_m(struct bio *bio) 164 { 165 return (struct mirror *) bio->bi_next; 166 } 167 168 static void bio_set_m(struct bio *bio, struct mirror *m) 169 { 170 bio->bi_next = (struct bio *) m; 171 } 172 173 static struct mirror *get_default_mirror(struct mirror_set *ms) 174 { 175 return &ms->mirror[atomic_read(&ms->default_mirror)]; 176 } 177 178 static void set_default_mirror(struct mirror *m) 179 { 180 struct mirror_set *ms = m->ms; 181 struct mirror *m0 = &(ms->mirror[0]); 182 183 atomic_set(&ms->default_mirror, m - m0); 184 } 185 186 static struct mirror *get_valid_mirror(struct mirror_set *ms) 187 { 188 struct mirror *m; 189 190 for (m = ms->mirror; m < ms->mirror + ms->nr_mirrors; m++) 191 if (!atomic_read(&m->error_count)) 192 return m; 193 194 return NULL; 195 } 196 197 /* fail_mirror 198 * @m: mirror device to fail 199 * @error_type: one of the enum's, DM_RAID1_*_ERROR 200 * 201 * If errors are being handled, record the type of 202 * error encountered for this device. If this type 203 * of error has already been recorded, we can return; 204 * otherwise, we must signal userspace by triggering 205 * an event. Additionally, if the device is the 206 * primary device, we must choose a new primary, but 207 * only if the mirror is in-sync. 208 * 209 * This function must not block. 210 */ 211 static void fail_mirror(struct mirror *m, enum dm_raid1_error error_type) 212 { 213 struct mirror_set *ms = m->ms; 214 struct mirror *new; 215 216 ms->leg_failure = 1; 217 218 /* 219 * error_count is used for nothing more than a 220 * simple way to tell if a device has encountered 221 * errors. 222 */ 223 atomic_inc(&m->error_count); 224 225 if (test_and_set_bit(error_type, &m->error_type)) 226 return; 227 228 if (!errors_handled(ms)) 229 return; 230 231 if (m != get_default_mirror(ms)) 232 goto out; 233 234 if (!ms->in_sync && !keep_log(ms)) { 235 /* 236 * Better to issue requests to same failing device 237 * than to risk returning corrupt data. 238 */ 239 DMERR("Primary mirror (%s) failed while out-of-sync: " 240 "Reads may fail.", m->dev->name); 241 goto out; 242 } 243 244 new = get_valid_mirror(ms); 245 if (new) 246 set_default_mirror(new); 247 else 248 DMWARN("All sides of mirror have failed."); 249 250 out: 251 schedule_work(&ms->trigger_event); 252 } 253 254 static int mirror_flush(struct dm_target *ti) 255 { 256 struct mirror_set *ms = ti->private; 257 unsigned long error_bits; 258 259 unsigned int i; 260 struct dm_io_region io[ms->nr_mirrors]; 261 struct mirror *m; 262 struct dm_io_request io_req = { 263 .bi_op = REQ_OP_WRITE, 264 .bi_op_flags = WRITE_FLUSH, 265 .mem.type = DM_IO_KMEM, 266 .mem.ptr.addr = NULL, 267 .client = ms->io_client, 268 }; 269 270 for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++) { 271 io[i].bdev = m->dev->bdev; 272 io[i].sector = 0; 273 io[i].count = 0; 274 } 275 276 error_bits = -1; 277 dm_io(&io_req, ms->nr_mirrors, io, &error_bits); 278 if (unlikely(error_bits != 0)) { 279 for (i = 0; i < ms->nr_mirrors; i++) 280 if (test_bit(i, &error_bits)) 281 fail_mirror(ms->mirror + i, 282 DM_RAID1_FLUSH_ERROR); 283 return -EIO; 284 } 285 286 return 0; 287 } 288 289 /*----------------------------------------------------------------- 290 * Recovery. 291 * 292 * When a mirror is first activated we may find that some regions 293 * are in the no-sync state. We have to recover these by 294 * recopying from the default mirror to all the others. 295 *---------------------------------------------------------------*/ 296 static void recovery_complete(int read_err, unsigned long write_err, 297 void *context) 298 { 299 struct dm_region *reg = context; 300 struct mirror_set *ms = dm_rh_region_context(reg); 301 int m, bit = 0; 302 303 if (read_err) { 304 /* Read error means the failure of default mirror. */ 305 DMERR_LIMIT("Unable to read primary mirror during recovery"); 306 fail_mirror(get_default_mirror(ms), DM_RAID1_SYNC_ERROR); 307 } 308 309 if (write_err) { 310 DMERR_LIMIT("Write error during recovery (error = 0x%lx)", 311 write_err); 312 /* 313 * Bits correspond to devices (excluding default mirror). 314 * The default mirror cannot change during recovery. 315 */ 316 for (m = 0; m < ms->nr_mirrors; m++) { 317 if (&ms->mirror[m] == get_default_mirror(ms)) 318 continue; 319 if (test_bit(bit, &write_err)) 320 fail_mirror(ms->mirror + m, 321 DM_RAID1_SYNC_ERROR); 322 bit++; 323 } 324 } 325 326 dm_rh_recovery_end(reg, !(read_err || write_err)); 327 } 328 329 static int recover(struct mirror_set *ms, struct dm_region *reg) 330 { 331 int r; 332 unsigned i; 333 struct dm_io_region from, to[DM_KCOPYD_MAX_REGIONS], *dest; 334 struct mirror *m; 335 unsigned long flags = 0; 336 region_t key = dm_rh_get_region_key(reg); 337 sector_t region_size = dm_rh_get_region_size(ms->rh); 338 339 /* fill in the source */ 340 m = get_default_mirror(ms); 341 from.bdev = m->dev->bdev; 342 from.sector = m->offset + dm_rh_region_to_sector(ms->rh, key); 343 if (key == (ms->nr_regions - 1)) { 344 /* 345 * The final region may be smaller than 346 * region_size. 347 */ 348 from.count = ms->ti->len & (region_size - 1); 349 if (!from.count) 350 from.count = region_size; 351 } else 352 from.count = region_size; 353 354 /* fill in the destinations */ 355 for (i = 0, dest = to; i < ms->nr_mirrors; i++) { 356 if (&ms->mirror[i] == get_default_mirror(ms)) 357 continue; 358 359 m = ms->mirror + i; 360 dest->bdev = m->dev->bdev; 361 dest->sector = m->offset + dm_rh_region_to_sector(ms->rh, key); 362 dest->count = from.count; 363 dest++; 364 } 365 366 /* hand to kcopyd */ 367 if (!errors_handled(ms)) 368 set_bit(DM_KCOPYD_IGNORE_ERROR, &flags); 369 370 r = dm_kcopyd_copy(ms->kcopyd_client, &from, ms->nr_mirrors - 1, to, 371 flags, recovery_complete, reg); 372 373 return r; 374 } 375 376 static void reset_ms_flags(struct mirror_set *ms) 377 { 378 unsigned int m; 379 380 ms->leg_failure = 0; 381 for (m = 0; m < ms->nr_mirrors; m++) { 382 atomic_set(&(ms->mirror[m].error_count), 0); 383 ms->mirror[m].error_type = 0; 384 } 385 } 386 387 static void do_recovery(struct mirror_set *ms) 388 { 389 struct dm_region *reg; 390 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 391 int r; 392 393 /* 394 * Start quiescing some regions. 395 */ 396 dm_rh_recovery_prepare(ms->rh); 397 398 /* 399 * Copy any already quiesced regions. 400 */ 401 while ((reg = dm_rh_recovery_start(ms->rh))) { 402 r = recover(ms, reg); 403 if (r) 404 dm_rh_recovery_end(reg, 0); 405 } 406 407 /* 408 * Update the in sync flag. 409 */ 410 if (!ms->in_sync && 411 (log->type->get_sync_count(log) == ms->nr_regions)) { 412 /* the sync is complete */ 413 dm_table_event(ms->ti->table); 414 ms->in_sync = 1; 415 reset_ms_flags(ms); 416 } 417 } 418 419 /*----------------------------------------------------------------- 420 * Reads 421 *---------------------------------------------------------------*/ 422 static struct mirror *choose_mirror(struct mirror_set *ms, sector_t sector) 423 { 424 struct mirror *m = get_default_mirror(ms); 425 426 do { 427 if (likely(!atomic_read(&m->error_count))) 428 return m; 429 430 if (m-- == ms->mirror) 431 m += ms->nr_mirrors; 432 } while (m != get_default_mirror(ms)); 433 434 return NULL; 435 } 436 437 static int default_ok(struct mirror *m) 438 { 439 struct mirror *default_mirror = get_default_mirror(m->ms); 440 441 return !atomic_read(&default_mirror->error_count); 442 } 443 444 static int mirror_available(struct mirror_set *ms, struct bio *bio) 445 { 446 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 447 region_t region = dm_rh_bio_to_region(ms->rh, bio); 448 449 if (log->type->in_sync(log, region, 0)) 450 return choose_mirror(ms, bio->bi_iter.bi_sector) ? 1 : 0; 451 452 return 0; 453 } 454 455 /* 456 * remap a buffer to a particular mirror. 457 */ 458 static sector_t map_sector(struct mirror *m, struct bio *bio) 459 { 460 if (unlikely(!bio->bi_iter.bi_size)) 461 return 0; 462 return m->offset + dm_target_offset(m->ms->ti, bio->bi_iter.bi_sector); 463 } 464 465 static void map_bio(struct mirror *m, struct bio *bio) 466 { 467 bio->bi_bdev = m->dev->bdev; 468 bio->bi_iter.bi_sector = map_sector(m, bio); 469 } 470 471 static void map_region(struct dm_io_region *io, struct mirror *m, 472 struct bio *bio) 473 { 474 io->bdev = m->dev->bdev; 475 io->sector = map_sector(m, bio); 476 io->count = bio_sectors(bio); 477 } 478 479 static void hold_bio(struct mirror_set *ms, struct bio *bio) 480 { 481 /* 482 * Lock is required to avoid race condition during suspend 483 * process. 484 */ 485 spin_lock_irq(&ms->lock); 486 487 if (atomic_read(&ms->suspend)) { 488 spin_unlock_irq(&ms->lock); 489 490 /* 491 * If device is suspended, complete the bio. 492 */ 493 if (dm_noflush_suspending(ms->ti)) 494 bio->bi_error = DM_ENDIO_REQUEUE; 495 else 496 bio->bi_error = -EIO; 497 498 bio_endio(bio); 499 return; 500 } 501 502 /* 503 * Hold bio until the suspend is complete. 504 */ 505 bio_list_add(&ms->holds, bio); 506 spin_unlock_irq(&ms->lock); 507 } 508 509 /*----------------------------------------------------------------- 510 * Reads 511 *---------------------------------------------------------------*/ 512 static void read_callback(unsigned long error, void *context) 513 { 514 struct bio *bio = context; 515 struct mirror *m; 516 517 m = bio_get_m(bio); 518 bio_set_m(bio, NULL); 519 520 if (likely(!error)) { 521 bio_endio(bio); 522 return; 523 } 524 525 fail_mirror(m, DM_RAID1_READ_ERROR); 526 527 if (likely(default_ok(m)) || mirror_available(m->ms, bio)) { 528 DMWARN_LIMIT("Read failure on mirror device %s. " 529 "Trying alternative device.", 530 m->dev->name); 531 queue_bio(m->ms, bio, bio_data_dir(bio)); 532 return; 533 } 534 535 DMERR_LIMIT("Read failure on mirror device %s. Failing I/O.", 536 m->dev->name); 537 bio_io_error(bio); 538 } 539 540 /* Asynchronous read. */ 541 static void read_async_bio(struct mirror *m, struct bio *bio) 542 { 543 struct dm_io_region io; 544 struct dm_io_request io_req = { 545 .bi_op = REQ_OP_READ, 546 .bi_op_flags = 0, 547 .mem.type = DM_IO_BIO, 548 .mem.ptr.bio = bio, 549 .notify.fn = read_callback, 550 .notify.context = bio, 551 .client = m->ms->io_client, 552 }; 553 554 map_region(&io, m, bio); 555 bio_set_m(bio, m); 556 BUG_ON(dm_io(&io_req, 1, &io, NULL)); 557 } 558 559 static inline int region_in_sync(struct mirror_set *ms, region_t region, 560 int may_block) 561 { 562 int state = dm_rh_get_state(ms->rh, region, may_block); 563 return state == DM_RH_CLEAN || state == DM_RH_DIRTY; 564 } 565 566 static void do_reads(struct mirror_set *ms, struct bio_list *reads) 567 { 568 region_t region; 569 struct bio *bio; 570 struct mirror *m; 571 572 while ((bio = bio_list_pop(reads))) { 573 region = dm_rh_bio_to_region(ms->rh, bio); 574 m = get_default_mirror(ms); 575 576 /* 577 * We can only read balance if the region is in sync. 578 */ 579 if (likely(region_in_sync(ms, region, 1))) 580 m = choose_mirror(ms, bio->bi_iter.bi_sector); 581 else if (m && atomic_read(&m->error_count)) 582 m = NULL; 583 584 if (likely(m)) 585 read_async_bio(m, bio); 586 else 587 bio_io_error(bio); 588 } 589 } 590 591 /*----------------------------------------------------------------- 592 * Writes. 593 * 594 * We do different things with the write io depending on the 595 * state of the region that it's in: 596 * 597 * SYNC: increment pending, use kcopyd to write to *all* mirrors 598 * RECOVERING: delay the io until recovery completes 599 * NOSYNC: increment pending, just write to the default mirror 600 *---------------------------------------------------------------*/ 601 602 603 static void write_callback(unsigned long error, void *context) 604 { 605 unsigned i; 606 struct bio *bio = (struct bio *) context; 607 struct mirror_set *ms; 608 int should_wake = 0; 609 unsigned long flags; 610 611 ms = bio_get_m(bio)->ms; 612 bio_set_m(bio, NULL); 613 614 /* 615 * NOTE: We don't decrement the pending count here, 616 * instead it is done by the targets endio function. 617 * This way we handle both writes to SYNC and NOSYNC 618 * regions with the same code. 619 */ 620 if (likely(!error)) { 621 bio_endio(bio); 622 return; 623 } 624 625 /* 626 * If the bio is discard, return an error, but do not 627 * degrade the array. 628 */ 629 if (bio_op(bio) == REQ_OP_DISCARD) { 630 bio->bi_error = -EOPNOTSUPP; 631 bio_endio(bio); 632 return; 633 } 634 635 for (i = 0; i < ms->nr_mirrors; i++) 636 if (test_bit(i, &error)) 637 fail_mirror(ms->mirror + i, DM_RAID1_WRITE_ERROR); 638 639 /* 640 * Need to raise event. Since raising 641 * events can block, we need to do it in 642 * the main thread. 643 */ 644 spin_lock_irqsave(&ms->lock, flags); 645 if (!ms->failures.head) 646 should_wake = 1; 647 bio_list_add(&ms->failures, bio); 648 spin_unlock_irqrestore(&ms->lock, flags); 649 if (should_wake) 650 wakeup_mirrord(ms); 651 } 652 653 static void do_write(struct mirror_set *ms, struct bio *bio) 654 { 655 unsigned int i; 656 struct dm_io_region io[ms->nr_mirrors], *dest = io; 657 struct mirror *m; 658 struct dm_io_request io_req = { 659 .bi_op = REQ_OP_WRITE, 660 .bi_op_flags = bio->bi_opf & WRITE_FLUSH_FUA, 661 .mem.type = DM_IO_BIO, 662 .mem.ptr.bio = bio, 663 .notify.fn = write_callback, 664 .notify.context = bio, 665 .client = ms->io_client, 666 }; 667 668 if (bio_op(bio) == REQ_OP_DISCARD) { 669 io_req.bi_op = REQ_OP_DISCARD; 670 io_req.mem.type = DM_IO_KMEM; 671 io_req.mem.ptr.addr = NULL; 672 } 673 674 for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++) 675 map_region(dest++, m, bio); 676 677 /* 678 * Use default mirror because we only need it to retrieve the reference 679 * to the mirror set in write_callback(). 680 */ 681 bio_set_m(bio, get_default_mirror(ms)); 682 683 BUG_ON(dm_io(&io_req, ms->nr_mirrors, io, NULL)); 684 } 685 686 static void do_writes(struct mirror_set *ms, struct bio_list *writes) 687 { 688 int state; 689 struct bio *bio; 690 struct bio_list sync, nosync, recover, *this_list = NULL; 691 struct bio_list requeue; 692 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 693 region_t region; 694 695 if (!writes->head) 696 return; 697 698 /* 699 * Classify each write. 700 */ 701 bio_list_init(&sync); 702 bio_list_init(&nosync); 703 bio_list_init(&recover); 704 bio_list_init(&requeue); 705 706 while ((bio = bio_list_pop(writes))) { 707 if ((bio->bi_opf & REQ_PREFLUSH) || 708 (bio_op(bio) == REQ_OP_DISCARD)) { 709 bio_list_add(&sync, bio); 710 continue; 711 } 712 713 region = dm_rh_bio_to_region(ms->rh, bio); 714 715 if (log->type->is_remote_recovering && 716 log->type->is_remote_recovering(log, region)) { 717 bio_list_add(&requeue, bio); 718 continue; 719 } 720 721 state = dm_rh_get_state(ms->rh, region, 1); 722 switch (state) { 723 case DM_RH_CLEAN: 724 case DM_RH_DIRTY: 725 this_list = &sync; 726 break; 727 728 case DM_RH_NOSYNC: 729 this_list = &nosync; 730 break; 731 732 case DM_RH_RECOVERING: 733 this_list = &recover; 734 break; 735 } 736 737 bio_list_add(this_list, bio); 738 } 739 740 /* 741 * Add bios that are delayed due to remote recovery 742 * back on to the write queue 743 */ 744 if (unlikely(requeue.head)) { 745 spin_lock_irq(&ms->lock); 746 bio_list_merge(&ms->writes, &requeue); 747 spin_unlock_irq(&ms->lock); 748 delayed_wake(ms); 749 } 750 751 /* 752 * Increment the pending counts for any regions that will 753 * be written to (writes to recover regions are going to 754 * be delayed). 755 */ 756 dm_rh_inc_pending(ms->rh, &sync); 757 dm_rh_inc_pending(ms->rh, &nosync); 758 759 /* 760 * If the flush fails on a previous call and succeeds here, 761 * we must not reset the log_failure variable. We need 762 * userspace interaction to do that. 763 */ 764 ms->log_failure = dm_rh_flush(ms->rh) ? 1 : ms->log_failure; 765 766 /* 767 * Dispatch io. 768 */ 769 if (unlikely(ms->log_failure) && errors_handled(ms)) { 770 spin_lock_irq(&ms->lock); 771 bio_list_merge(&ms->failures, &sync); 772 spin_unlock_irq(&ms->lock); 773 wakeup_mirrord(ms); 774 } else 775 while ((bio = bio_list_pop(&sync))) 776 do_write(ms, bio); 777 778 while ((bio = bio_list_pop(&recover))) 779 dm_rh_delay(ms->rh, bio); 780 781 while ((bio = bio_list_pop(&nosync))) { 782 if (unlikely(ms->leg_failure) && errors_handled(ms) && !keep_log(ms)) { 783 spin_lock_irq(&ms->lock); 784 bio_list_add(&ms->failures, bio); 785 spin_unlock_irq(&ms->lock); 786 wakeup_mirrord(ms); 787 } else { 788 map_bio(get_default_mirror(ms), bio); 789 generic_make_request(bio); 790 } 791 } 792 } 793 794 static void do_failures(struct mirror_set *ms, struct bio_list *failures) 795 { 796 struct bio *bio; 797 798 if (likely(!failures->head)) 799 return; 800 801 /* 802 * If the log has failed, unattempted writes are being 803 * put on the holds list. We can't issue those writes 804 * until a log has been marked, so we must store them. 805 * 806 * If a 'noflush' suspend is in progress, we can requeue 807 * the I/O's to the core. This give userspace a chance 808 * to reconfigure the mirror, at which point the core 809 * will reissue the writes. If the 'noflush' flag is 810 * not set, we have no choice but to return errors. 811 * 812 * Some writes on the failures list may have been 813 * submitted before the log failure and represent a 814 * failure to write to one of the devices. It is ok 815 * for us to treat them the same and requeue them 816 * as well. 817 */ 818 while ((bio = bio_list_pop(failures))) { 819 if (!ms->log_failure) { 820 ms->in_sync = 0; 821 dm_rh_mark_nosync(ms->rh, bio); 822 } 823 824 /* 825 * If all the legs are dead, fail the I/O. 826 * If the device has failed and keep_log is enabled, 827 * fail the I/O. 828 * 829 * If we have been told to handle errors, and keep_log 830 * isn't enabled, hold the bio and wait for userspace to 831 * deal with the problem. 832 * 833 * Otherwise pretend that the I/O succeeded. (This would 834 * be wrong if the failed leg returned after reboot and 835 * got replicated back to the good legs.) 836 */ 837 if (unlikely(!get_valid_mirror(ms) || (keep_log(ms) && ms->log_failure))) 838 bio_io_error(bio); 839 else if (errors_handled(ms) && !keep_log(ms)) 840 hold_bio(ms, bio); 841 else 842 bio_endio(bio); 843 } 844 } 845 846 static void trigger_event(struct work_struct *work) 847 { 848 struct mirror_set *ms = 849 container_of(work, struct mirror_set, trigger_event); 850 851 dm_table_event(ms->ti->table); 852 } 853 854 /*----------------------------------------------------------------- 855 * kmirrord 856 *---------------------------------------------------------------*/ 857 static void do_mirror(struct work_struct *work) 858 { 859 struct mirror_set *ms = container_of(work, struct mirror_set, 860 kmirrord_work); 861 struct bio_list reads, writes, failures; 862 unsigned long flags; 863 864 spin_lock_irqsave(&ms->lock, flags); 865 reads = ms->reads; 866 writes = ms->writes; 867 failures = ms->failures; 868 bio_list_init(&ms->reads); 869 bio_list_init(&ms->writes); 870 bio_list_init(&ms->failures); 871 spin_unlock_irqrestore(&ms->lock, flags); 872 873 dm_rh_update_states(ms->rh, errors_handled(ms)); 874 do_recovery(ms); 875 do_reads(ms, &reads); 876 do_writes(ms, &writes); 877 do_failures(ms, &failures); 878 } 879 880 /*----------------------------------------------------------------- 881 * Target functions 882 *---------------------------------------------------------------*/ 883 static struct mirror_set *alloc_context(unsigned int nr_mirrors, 884 uint32_t region_size, 885 struct dm_target *ti, 886 struct dm_dirty_log *dl) 887 { 888 size_t len; 889 struct mirror_set *ms = NULL; 890 891 len = sizeof(*ms) + (sizeof(ms->mirror[0]) * nr_mirrors); 892 893 ms = kzalloc(len, GFP_KERNEL); 894 if (!ms) { 895 ti->error = "Cannot allocate mirror context"; 896 return NULL; 897 } 898 899 spin_lock_init(&ms->lock); 900 bio_list_init(&ms->reads); 901 bio_list_init(&ms->writes); 902 bio_list_init(&ms->failures); 903 bio_list_init(&ms->holds); 904 905 ms->ti = ti; 906 ms->nr_mirrors = nr_mirrors; 907 ms->nr_regions = dm_sector_div_up(ti->len, region_size); 908 ms->in_sync = 0; 909 ms->log_failure = 0; 910 ms->leg_failure = 0; 911 atomic_set(&ms->suspend, 0); 912 atomic_set(&ms->default_mirror, DEFAULT_MIRROR); 913 914 ms->io_client = dm_io_client_create(); 915 if (IS_ERR(ms->io_client)) { 916 ti->error = "Error creating dm_io client"; 917 kfree(ms); 918 return NULL; 919 } 920 921 ms->rh = dm_region_hash_create(ms, dispatch_bios, wakeup_mirrord, 922 wakeup_all_recovery_waiters, 923 ms->ti->begin, MAX_RECOVERY, 924 dl, region_size, ms->nr_regions); 925 if (IS_ERR(ms->rh)) { 926 ti->error = "Error creating dirty region hash"; 927 dm_io_client_destroy(ms->io_client); 928 kfree(ms); 929 return NULL; 930 } 931 932 return ms; 933 } 934 935 static void free_context(struct mirror_set *ms, struct dm_target *ti, 936 unsigned int m) 937 { 938 while (m--) 939 dm_put_device(ti, ms->mirror[m].dev); 940 941 dm_io_client_destroy(ms->io_client); 942 dm_region_hash_destroy(ms->rh); 943 kfree(ms); 944 } 945 946 static int get_mirror(struct mirror_set *ms, struct dm_target *ti, 947 unsigned int mirror, char **argv) 948 { 949 unsigned long long offset; 950 char dummy; 951 int ret; 952 953 if (sscanf(argv[1], "%llu%c", &offset, &dummy) != 1) { 954 ti->error = "Invalid offset"; 955 return -EINVAL; 956 } 957 958 ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), 959 &ms->mirror[mirror].dev); 960 if (ret) { 961 ti->error = "Device lookup failure"; 962 return ret; 963 } 964 965 ms->mirror[mirror].ms = ms; 966 atomic_set(&(ms->mirror[mirror].error_count), 0); 967 ms->mirror[mirror].error_type = 0; 968 ms->mirror[mirror].offset = offset; 969 970 return 0; 971 } 972 973 /* 974 * Create dirty log: log_type #log_params <log_params> 975 */ 976 static struct dm_dirty_log *create_dirty_log(struct dm_target *ti, 977 unsigned argc, char **argv, 978 unsigned *args_used) 979 { 980 unsigned param_count; 981 struct dm_dirty_log *dl; 982 char dummy; 983 984 if (argc < 2) { 985 ti->error = "Insufficient mirror log arguments"; 986 return NULL; 987 } 988 989 if (sscanf(argv[1], "%u%c", ¶m_count, &dummy) != 1) { 990 ti->error = "Invalid mirror log argument count"; 991 return NULL; 992 } 993 994 *args_used = 2 + param_count; 995 996 if (argc < *args_used) { 997 ti->error = "Insufficient mirror log arguments"; 998 return NULL; 999 } 1000 1001 dl = dm_dirty_log_create(argv[0], ti, mirror_flush, param_count, 1002 argv + 2); 1003 if (!dl) { 1004 ti->error = "Error creating mirror dirty log"; 1005 return NULL; 1006 } 1007 1008 return dl; 1009 } 1010 1011 static int parse_features(struct mirror_set *ms, unsigned argc, char **argv, 1012 unsigned *args_used) 1013 { 1014 unsigned num_features; 1015 struct dm_target *ti = ms->ti; 1016 char dummy; 1017 int i; 1018 1019 *args_used = 0; 1020 1021 if (!argc) 1022 return 0; 1023 1024 if (sscanf(argv[0], "%u%c", &num_features, &dummy) != 1) { 1025 ti->error = "Invalid number of features"; 1026 return -EINVAL; 1027 } 1028 1029 argc--; 1030 argv++; 1031 (*args_used)++; 1032 1033 if (num_features > argc) { 1034 ti->error = "Not enough arguments to support feature count"; 1035 return -EINVAL; 1036 } 1037 1038 for (i = 0; i < num_features; i++) { 1039 if (!strcmp("handle_errors", argv[0])) 1040 ms->features |= DM_RAID1_HANDLE_ERRORS; 1041 else if (!strcmp("keep_log", argv[0])) 1042 ms->features |= DM_RAID1_KEEP_LOG; 1043 else { 1044 ti->error = "Unrecognised feature requested"; 1045 return -EINVAL; 1046 } 1047 1048 argc--; 1049 argv++; 1050 (*args_used)++; 1051 } 1052 if (!errors_handled(ms) && keep_log(ms)) { 1053 ti->error = "keep_log feature requires the handle_errors feature"; 1054 return -EINVAL; 1055 } 1056 1057 return 0; 1058 } 1059 1060 /* 1061 * Construct a mirror mapping: 1062 * 1063 * log_type #log_params <log_params> 1064 * #mirrors [mirror_path offset]{2,} 1065 * [#features <features>] 1066 * 1067 * log_type is "core" or "disk" 1068 * #log_params is between 1 and 3 1069 * 1070 * If present, supported features are "handle_errors" and "keep_log". 1071 */ 1072 static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv) 1073 { 1074 int r; 1075 unsigned int nr_mirrors, m, args_used; 1076 struct mirror_set *ms; 1077 struct dm_dirty_log *dl; 1078 char dummy; 1079 1080 dl = create_dirty_log(ti, argc, argv, &args_used); 1081 if (!dl) 1082 return -EINVAL; 1083 1084 argv += args_used; 1085 argc -= args_used; 1086 1087 if (!argc || sscanf(argv[0], "%u%c", &nr_mirrors, &dummy) != 1 || 1088 nr_mirrors < 2 || nr_mirrors > DM_KCOPYD_MAX_REGIONS + 1) { 1089 ti->error = "Invalid number of mirrors"; 1090 dm_dirty_log_destroy(dl); 1091 return -EINVAL; 1092 } 1093 1094 argv++, argc--; 1095 1096 if (argc < nr_mirrors * 2) { 1097 ti->error = "Too few mirror arguments"; 1098 dm_dirty_log_destroy(dl); 1099 return -EINVAL; 1100 } 1101 1102 ms = alloc_context(nr_mirrors, dl->type->get_region_size(dl), ti, dl); 1103 if (!ms) { 1104 dm_dirty_log_destroy(dl); 1105 return -ENOMEM; 1106 } 1107 1108 /* Get the mirror parameter sets */ 1109 for (m = 0; m < nr_mirrors; m++) { 1110 r = get_mirror(ms, ti, m, argv); 1111 if (r) { 1112 free_context(ms, ti, m); 1113 return r; 1114 } 1115 argv += 2; 1116 argc -= 2; 1117 } 1118 1119 ti->private = ms; 1120 1121 r = dm_set_target_max_io_len(ti, dm_rh_get_region_size(ms->rh)); 1122 if (r) 1123 goto err_free_context; 1124 1125 ti->num_flush_bios = 1; 1126 ti->num_discard_bios = 1; 1127 ti->per_io_data_size = sizeof(struct dm_raid1_bio_record); 1128 ti->discard_zeroes_data_unsupported = true; 1129 1130 ms->kmirrord_wq = alloc_workqueue("kmirrord", WQ_MEM_RECLAIM, 0); 1131 if (!ms->kmirrord_wq) { 1132 DMERR("couldn't start kmirrord"); 1133 r = -ENOMEM; 1134 goto err_free_context; 1135 } 1136 INIT_WORK(&ms->kmirrord_work, do_mirror); 1137 init_timer(&ms->timer); 1138 ms->timer_pending = 0; 1139 INIT_WORK(&ms->trigger_event, trigger_event); 1140 1141 r = parse_features(ms, argc, argv, &args_used); 1142 if (r) 1143 goto err_destroy_wq; 1144 1145 argv += args_used; 1146 argc -= args_used; 1147 1148 /* 1149 * Any read-balancing addition depends on the 1150 * DM_RAID1_HANDLE_ERRORS flag being present. 1151 * This is because the decision to balance depends 1152 * on the sync state of a region. If the above 1153 * flag is not present, we ignore errors; and 1154 * the sync state may be inaccurate. 1155 */ 1156 1157 if (argc) { 1158 ti->error = "Too many mirror arguments"; 1159 r = -EINVAL; 1160 goto err_destroy_wq; 1161 } 1162 1163 ms->kcopyd_client = dm_kcopyd_client_create(&dm_kcopyd_throttle); 1164 if (IS_ERR(ms->kcopyd_client)) { 1165 r = PTR_ERR(ms->kcopyd_client); 1166 goto err_destroy_wq; 1167 } 1168 1169 wakeup_mirrord(ms); 1170 return 0; 1171 1172 err_destroy_wq: 1173 destroy_workqueue(ms->kmirrord_wq); 1174 err_free_context: 1175 free_context(ms, ti, ms->nr_mirrors); 1176 return r; 1177 } 1178 1179 static void mirror_dtr(struct dm_target *ti) 1180 { 1181 struct mirror_set *ms = (struct mirror_set *) ti->private; 1182 1183 del_timer_sync(&ms->timer); 1184 flush_workqueue(ms->kmirrord_wq); 1185 flush_work(&ms->trigger_event); 1186 dm_kcopyd_client_destroy(ms->kcopyd_client); 1187 destroy_workqueue(ms->kmirrord_wq); 1188 free_context(ms, ti, ms->nr_mirrors); 1189 } 1190 1191 /* 1192 * Mirror mapping function 1193 */ 1194 static int mirror_map(struct dm_target *ti, struct bio *bio) 1195 { 1196 int r, rw = bio_data_dir(bio); 1197 struct mirror *m; 1198 struct mirror_set *ms = ti->private; 1199 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 1200 struct dm_raid1_bio_record *bio_record = 1201 dm_per_bio_data(bio, sizeof(struct dm_raid1_bio_record)); 1202 1203 bio_record->details.bi_bdev = NULL; 1204 1205 if (rw == WRITE) { 1206 /* Save region for mirror_end_io() handler */ 1207 bio_record->write_region = dm_rh_bio_to_region(ms->rh, bio); 1208 queue_bio(ms, bio, rw); 1209 return DM_MAPIO_SUBMITTED; 1210 } 1211 1212 r = log->type->in_sync(log, dm_rh_bio_to_region(ms->rh, bio), 0); 1213 if (r < 0 && r != -EWOULDBLOCK) 1214 return r; 1215 1216 /* 1217 * If region is not in-sync queue the bio. 1218 */ 1219 if (!r || (r == -EWOULDBLOCK)) { 1220 if (bio->bi_opf & REQ_RAHEAD) 1221 return -EWOULDBLOCK; 1222 1223 queue_bio(ms, bio, rw); 1224 return DM_MAPIO_SUBMITTED; 1225 } 1226 1227 /* 1228 * The region is in-sync and we can perform reads directly. 1229 * Store enough information so we can retry if it fails. 1230 */ 1231 m = choose_mirror(ms, bio->bi_iter.bi_sector); 1232 if (unlikely(!m)) 1233 return -EIO; 1234 1235 dm_bio_record(&bio_record->details, bio); 1236 bio_record->m = m; 1237 1238 map_bio(m, bio); 1239 1240 return DM_MAPIO_REMAPPED; 1241 } 1242 1243 static int mirror_end_io(struct dm_target *ti, struct bio *bio, int error) 1244 { 1245 int rw = bio_data_dir(bio); 1246 struct mirror_set *ms = (struct mirror_set *) ti->private; 1247 struct mirror *m = NULL; 1248 struct dm_bio_details *bd = NULL; 1249 struct dm_raid1_bio_record *bio_record = 1250 dm_per_bio_data(bio, sizeof(struct dm_raid1_bio_record)); 1251 1252 /* 1253 * We need to dec pending if this was a write. 1254 */ 1255 if (rw == WRITE) { 1256 if (!(bio->bi_opf & REQ_PREFLUSH) && 1257 bio_op(bio) != REQ_OP_DISCARD) 1258 dm_rh_dec(ms->rh, bio_record->write_region); 1259 return error; 1260 } 1261 1262 if (error == -EOPNOTSUPP) 1263 goto out; 1264 1265 if ((error == -EWOULDBLOCK) && (bio->bi_opf & REQ_RAHEAD)) 1266 goto out; 1267 1268 if (unlikely(error)) { 1269 if (!bio_record->details.bi_bdev) { 1270 /* 1271 * There wasn't enough memory to record necessary 1272 * information for a retry or there was no other 1273 * mirror in-sync. 1274 */ 1275 DMERR_LIMIT("Mirror read failed."); 1276 return -EIO; 1277 } 1278 1279 m = bio_record->m; 1280 1281 DMERR("Mirror read failed from %s. Trying alternative device.", 1282 m->dev->name); 1283 1284 fail_mirror(m, DM_RAID1_READ_ERROR); 1285 1286 /* 1287 * A failed read is requeued for another attempt using an intact 1288 * mirror. 1289 */ 1290 if (default_ok(m) || mirror_available(ms, bio)) { 1291 bd = &bio_record->details; 1292 1293 dm_bio_restore(bd, bio); 1294 bio_record->details.bi_bdev = NULL; 1295 1296 queue_bio(ms, bio, rw); 1297 return DM_ENDIO_INCOMPLETE; 1298 } 1299 DMERR("All replicated volumes dead, failing I/O"); 1300 } 1301 1302 out: 1303 bio_record->details.bi_bdev = NULL; 1304 1305 return error; 1306 } 1307 1308 static void mirror_presuspend(struct dm_target *ti) 1309 { 1310 struct mirror_set *ms = (struct mirror_set *) ti->private; 1311 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 1312 1313 struct bio_list holds; 1314 struct bio *bio; 1315 1316 atomic_set(&ms->suspend, 1); 1317 1318 /* 1319 * Process bios in the hold list to start recovery waiting 1320 * for bios in the hold list. After the process, no bio has 1321 * a chance to be added in the hold list because ms->suspend 1322 * is set. 1323 */ 1324 spin_lock_irq(&ms->lock); 1325 holds = ms->holds; 1326 bio_list_init(&ms->holds); 1327 spin_unlock_irq(&ms->lock); 1328 1329 while ((bio = bio_list_pop(&holds))) 1330 hold_bio(ms, bio); 1331 1332 /* 1333 * We must finish up all the work that we've 1334 * generated (i.e. recovery work). 1335 */ 1336 dm_rh_stop_recovery(ms->rh); 1337 1338 wait_event(_kmirrord_recovery_stopped, 1339 !dm_rh_recovery_in_flight(ms->rh)); 1340 1341 if (log->type->presuspend && log->type->presuspend(log)) 1342 /* FIXME: need better error handling */ 1343 DMWARN("log presuspend failed"); 1344 1345 /* 1346 * Now that recovery is complete/stopped and the 1347 * delayed bios are queued, we need to wait for 1348 * the worker thread to complete. This way, 1349 * we know that all of our I/O has been pushed. 1350 */ 1351 flush_workqueue(ms->kmirrord_wq); 1352 } 1353 1354 static void mirror_postsuspend(struct dm_target *ti) 1355 { 1356 struct mirror_set *ms = ti->private; 1357 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 1358 1359 if (log->type->postsuspend && log->type->postsuspend(log)) 1360 /* FIXME: need better error handling */ 1361 DMWARN("log postsuspend failed"); 1362 } 1363 1364 static void mirror_resume(struct dm_target *ti) 1365 { 1366 struct mirror_set *ms = ti->private; 1367 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 1368 1369 atomic_set(&ms->suspend, 0); 1370 if (log->type->resume && log->type->resume(log)) 1371 /* FIXME: need better error handling */ 1372 DMWARN("log resume failed"); 1373 dm_rh_start_recovery(ms->rh); 1374 } 1375 1376 /* 1377 * device_status_char 1378 * @m: mirror device/leg we want the status of 1379 * 1380 * We return one character representing the most severe error 1381 * we have encountered. 1382 * A => Alive - No failures 1383 * D => Dead - A write failure occurred leaving mirror out-of-sync 1384 * S => Sync - A sychronization failure occurred, mirror out-of-sync 1385 * R => Read - A read failure occurred, mirror data unaffected 1386 * 1387 * Returns: <char> 1388 */ 1389 static char device_status_char(struct mirror *m) 1390 { 1391 if (!atomic_read(&(m->error_count))) 1392 return 'A'; 1393 1394 return (test_bit(DM_RAID1_FLUSH_ERROR, &(m->error_type))) ? 'F' : 1395 (test_bit(DM_RAID1_WRITE_ERROR, &(m->error_type))) ? 'D' : 1396 (test_bit(DM_RAID1_SYNC_ERROR, &(m->error_type))) ? 'S' : 1397 (test_bit(DM_RAID1_READ_ERROR, &(m->error_type))) ? 'R' : 'U'; 1398 } 1399 1400 1401 static void mirror_status(struct dm_target *ti, status_type_t type, 1402 unsigned status_flags, char *result, unsigned maxlen) 1403 { 1404 unsigned int m, sz = 0; 1405 int num_feature_args = 0; 1406 struct mirror_set *ms = (struct mirror_set *) ti->private; 1407 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); 1408 char buffer[ms->nr_mirrors + 1]; 1409 1410 switch (type) { 1411 case STATUSTYPE_INFO: 1412 DMEMIT("%d ", ms->nr_mirrors); 1413 for (m = 0; m < ms->nr_mirrors; m++) { 1414 DMEMIT("%s ", ms->mirror[m].dev->name); 1415 buffer[m] = device_status_char(&(ms->mirror[m])); 1416 } 1417 buffer[m] = '\0'; 1418 1419 DMEMIT("%llu/%llu 1 %s ", 1420 (unsigned long long)log->type->get_sync_count(log), 1421 (unsigned long long)ms->nr_regions, buffer); 1422 1423 sz += log->type->status(log, type, result+sz, maxlen-sz); 1424 1425 break; 1426 1427 case STATUSTYPE_TABLE: 1428 sz = log->type->status(log, type, result, maxlen); 1429 1430 DMEMIT("%d", ms->nr_mirrors); 1431 for (m = 0; m < ms->nr_mirrors; m++) 1432 DMEMIT(" %s %llu", ms->mirror[m].dev->name, 1433 (unsigned long long)ms->mirror[m].offset); 1434 1435 num_feature_args += !!errors_handled(ms); 1436 num_feature_args += !!keep_log(ms); 1437 if (num_feature_args) { 1438 DMEMIT(" %d", num_feature_args); 1439 if (errors_handled(ms)) 1440 DMEMIT(" handle_errors"); 1441 if (keep_log(ms)) 1442 DMEMIT(" keep_log"); 1443 } 1444 1445 break; 1446 } 1447 } 1448 1449 static int mirror_iterate_devices(struct dm_target *ti, 1450 iterate_devices_callout_fn fn, void *data) 1451 { 1452 struct mirror_set *ms = ti->private; 1453 int ret = 0; 1454 unsigned i; 1455 1456 for (i = 0; !ret && i < ms->nr_mirrors; i++) 1457 ret = fn(ti, ms->mirror[i].dev, 1458 ms->mirror[i].offset, ti->len, data); 1459 1460 return ret; 1461 } 1462 1463 static struct target_type mirror_target = { 1464 .name = "mirror", 1465 .version = {1, 14, 0}, 1466 .module = THIS_MODULE, 1467 .ctr = mirror_ctr, 1468 .dtr = mirror_dtr, 1469 .map = mirror_map, 1470 .end_io = mirror_end_io, 1471 .presuspend = mirror_presuspend, 1472 .postsuspend = mirror_postsuspend, 1473 .resume = mirror_resume, 1474 .status = mirror_status, 1475 .iterate_devices = mirror_iterate_devices, 1476 }; 1477 1478 static int __init dm_mirror_init(void) 1479 { 1480 int r; 1481 1482 r = dm_register_target(&mirror_target); 1483 if (r < 0) { 1484 DMERR("Failed to register mirror target"); 1485 goto bad_target; 1486 } 1487 1488 return 0; 1489 1490 bad_target: 1491 return r; 1492 } 1493 1494 static void __exit dm_mirror_exit(void) 1495 { 1496 dm_unregister_target(&mirror_target); 1497 } 1498 1499 /* Module hooks */ 1500 module_init(dm_mirror_init); 1501 module_exit(dm_mirror_exit); 1502 1503 MODULE_DESCRIPTION(DM_NAME " mirror target"); 1504 MODULE_AUTHOR("Joe Thornber"); 1505 MODULE_LICENSE("GPL"); 1506