drivers/md/raid5-ppl.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Partial Parity Log for closing the RAID5 write hole
   4  * Copyright (c) 2017, Intel Corporation.
   5  */
   6
   7 #include <linux/kernel.h>
   8 #include <linux/blkdev.h>
   9 #include <linux/slab.h>
  10 #include <linux/crc32c.h>
  11 #include <linux/async_tx.h>
  12 #include <linux/raid/md_p.h>
  13 #include "md.h"
  14 #include "raid5.h"
  15 #include "raid5-log.h"
  16
  17 /*
  18  * PPL consists of a 4KB header (struct ppl_header) and at least 128KB for
  19  * partial parity data. The header contains an array of entries
  20  * (struct ppl_header_entry) which describe the logged write requests.
  21  * Partial parity for the entries comes after the header, written in the same
  22  * sequence as the entries:
  23  *
  24  * Header
  25  *   entry0
  26  *   ...
  27  *   entryN
  28  * PP data
  29  *   PP for entry0
  30  *   ...
  31  *   PP for entryN
  32  *
  33  * An entry describes one or more consecutive stripe_heads, up to a full
  34  * stripe. The modifed raid data chunks form an m-by-n matrix, where m is the
  35  * number of stripe_heads in the entry and n is the number of modified data
  36  * disks. Every stripe_head in the entry must write to the same data disks.
  37  * An example of a valid case described by a single entry (writes to the first
  38  * stripe of a 4 disk array, 16k chunk size):
  39  *
  40  * sh->sector   dd0   dd1   dd2    ppl
  41  *            +-----+-----+-----+
  42  * 0          | --- | --- | --- | +----+
  43  * 8          | -W- | -W- | --- | | pp |   data_sector = 8
  44  * 16         | -W- | -W- | --- | | pp |   data_size = 3 * 2 * 4k
  45  * 24         | -W- | -W- | --- | | pp |   pp_size = 3 * 4k
  46  *            +-----+-----+-----+ +----+
  47  *
  48  * data_sector is the first raid sector of the modified data, data_size is the
  49  * total size of modified data and pp_size is the size of partial parity for
  50  * this entry. Entries for full stripe writes contain no partial parity
  51  * (pp_size = 0), they only mark the stripes for which parity should be
  52  * recalculated after an unclean shutdown. Every entry holds a checksum of its
  53  * partial parity, the header also has a checksum of the header itself.
  54  *
  55  * A write request is always logged to the PPL instance stored on the parity
  56  * disk of the corresponding stripe. For each member disk there is one ppl_log
  57  * used to handle logging for this disk, independently from others. They are
  58  * grouped in child_logs array in struct ppl_conf, which is assigned to
  59  * r5conf->log_private.
  60  *
  61  * ppl_io_unit represents a full PPL write, header_page contains the ppl_header.
  62  * PPL entries for logged stripes are added in ppl_log_stripe(). A stripe_head
  63  * can be appended to the last entry if it meets the conditions for a valid
  64  * entry described above, otherwise a new entry is added. Checksums of entries
  65  * are calculated incrementally as stripes containing partial parity are being
  66  * added. ppl_submit_iounit() calculates the checksum of the header and submits
  67  * a bio containing the header page and partial parity pages (sh->ppl_page) for
  68  * all stripes of the io_unit. When the PPL write completes, the stripes
  69  * associated with the io_unit are released and raid5d starts writing their data
  70  * and parity. When all stripes are written, the io_unit is freed and the next
  71  * can be submitted.
  72  *
  73  * An io_unit is used to gather stripes until it is submitted or becomes full
  74  * (if the maximum number of entries or size of PPL is reached). Another io_unit
  75  * can't be submitted until the previous has completed (PPL and stripe
  76  * data+parity is written). The log->io_list tracks all io_units of a log
  77  * (for a single member disk). New io_units are added to the end of the list
  78  * and the first io_unit is submitted, if it is not submitted already.
  79  * The current io_unit accepting new stripes is always at the end of the list.
  80  *
  81  * If write-back cache is enabled for any of the disks in the array, its data
  82  * must be flushed before next io_unit is submitted.
  83  */
  84
  85 #define PPL_SPACE_SIZE (128 * 1024)
  86
  87 struct ppl_conf {
  88         struct mddev *mddev;
  89
  90         /* array of child logs, one for each raid disk */
  91         struct ppl_log *child_logs;
  92         int count;
  93
  94         int block_size;         /* the logical block size used for data_sector
  95                                  * in ppl_header_entry */
  96         u32 signature;          /* raid array identifier */
  97         atomic64_t seq;         /* current log write sequence number */
  98
  99         struct kmem_cache *io_kc;
 100         mempool_t io_pool;
 101         struct bio_set bs;
 102         struct bio_set flush_bs;
 103
 104         /* used only for recovery */
 105         int recovered_entries;
 106         int mismatch_count;
 107
 108         /* stripes to retry if failed to allocate io_unit */
 109         struct list_head no_mem_stripes;
 110         spinlock_t no_mem_stripes_lock;
 111
 112         unsigned short write_hint;
 113 };
 114
 115 struct ppl_log {
 116         struct ppl_conf *ppl_conf;      /* shared between all log instances */
 117
 118         struct md_rdev *rdev;           /* array member disk associated with
 119                                          * this log instance */
 120         struct mutex io_mutex;
 121         struct ppl_io_unit *current_io; /* current io_unit accepting new data
 122                                          * always at the end of io_list */
 123         spinlock_t io_list_lock;
 124         struct list_head io_list;       /* all io_units of this log */
 125
 126         sector_t next_io_sector;
 127         unsigned int entry_space;
 128         bool use_multippl;
 129         bool wb_cache_on;
 130         unsigned long disk_flush_bitmap;
 131 };
 132
 133 #define PPL_IO_INLINE_BVECS 32
 134
 135 struct ppl_io_unit {
 136         struct ppl_log *log;
 137
 138         struct page *header_page;       /* for ppl_header */
 139
 140         unsigned int entries_count;     /* number of entries in ppl_header */
 141         unsigned int pp_size;           /* total size current of partial parity */
 142
 143         u64 seq;                        /* sequence number of this log write */
 144         struct list_head log_sibling;   /* log->io_list */
 145
 146         struct list_head stripe_list;   /* stripes added to the io_unit */
 147         atomic_t pending_stripes;       /* how many stripes not written to raid */
 148         atomic_t pending_flushes;       /* how many disk flushes are in progress */
 149
 150         bool submitted;                 /* true if write to log started */
 151
 152         /* inline bio and its biovec for submitting the iounit */
 153         struct bio bio;
 154         struct bio_vec biovec[PPL_IO_INLINE_BVECS];
 155 };
 156
 157 struct dma_async_tx_descriptor *
 158 ops_run_partial_parity(struct stripe_head *sh, struct raid5_percpu *percpu,
 159                        struct dma_async_tx_descriptor *tx)
 160 {
 161         int disks = sh->disks;
 162         struct page **srcs = percpu->scribble;
 163         int count = 0, pd_idx = sh->pd_idx, i;
 164         struct async_submit_ctl submit;
 165
 166         pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector);
 167
 168         /*
 169          * Partial parity is the XOR of stripe data chunks that are not changed
 170          * during the write request. Depending on available data
 171          * (read-modify-write vs. reconstruct-write case) we calculate it
 172          * differently.
 173          */
 174         if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
 175                 /*
 176                  * rmw: xor old data and parity from updated disks
 177                  * This is calculated earlier by ops_run_prexor5() so just copy
 178                  * the parity dev page.
 179                  */
 180                 srcs[count++] = sh->dev[pd_idx].page;
 181         } else if (sh->reconstruct_state == reconstruct_state_drain_run) {
 182                 /* rcw: xor data from all not updated disks */
 183                 for (i = disks; i--;) {
 184                         struct r5dev *dev = &sh->dev[i];
 185                         if (test_bit(R5_UPTODATE, &dev->flags))
 186                                 srcs[count++] = dev->page;
 187                 }
 188         } else {
 189                 return tx;
 190         }
 191
 192         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, tx,
 193                           NULL, sh, (void *) (srcs + sh->disks + 2));
 194
 195         if (count == 1)
 196                 tx = async_memcpy(sh->ppl_page, srcs[0], 0, 0, PAGE_SIZE,
 197                                   &submit);
 198         else
 199                 tx = async_xor(sh->ppl_page, srcs, 0, count, PAGE_SIZE,
 200                                &submit);
 201
 202         return tx;
 203 }
 204
 205 static void *ppl_io_pool_alloc(gfp_t gfp_mask, void *pool_data)
 206 {
 207         struct kmem_cache *kc = pool_data;
 208         struct ppl_io_unit *io;
 209
 210         io = kmem_cache_alloc(kc, gfp_mask);
 211         if (!io)
 212                 return NULL;
 213
 214         io->header_page = alloc_page(gfp_mask);
 215         if (!io->header_page) {
 216                 kmem_cache_free(kc, io);
 217                 return NULL;
 218         }
 219
 220         return io;
 221 }
 222
 223 static void ppl_io_pool_free(void *element, void *pool_data)
 224 {
 225         struct kmem_cache *kc = pool_data;
 226         struct ppl_io_unit *io = element;
 227
 228         __free_page(io->header_page);
 229         kmem_cache_free(kc, io);
 230 }
 231
 232 static struct ppl_io_unit *ppl_new_iounit(struct ppl_log *log,
 233                                           struct stripe_head *sh)
 234 {
 235         struct ppl_conf *ppl_conf = log->ppl_conf;
 236         struct ppl_io_unit *io;
 237         struct ppl_header *pplhdr;
 238         struct page *header_page;
 239
 240         io = mempool_alloc(&ppl_conf->io_pool, GFP_NOWAIT);
 241         if (!io)
 242                 return NULL;
 243
 244         header_page = io->header_page;
 245         memset(io, 0, sizeof(*io));
 246         io->header_page = header_page;
 247
 248         io->log = log;
 249         INIT_LIST_HEAD(&io->log_sibling);
 250         INIT_LIST_HEAD(&io->stripe_list);
 251         atomic_set(&io->pending_stripes, 0);
 252         atomic_set(&io->pending_flushes, 0);
 253         bio_init(&io->bio, log->rdev->bdev, io->biovec, PPL_IO_INLINE_BVECS,
 254                  REQ_OP_WRITE | REQ_FUA);
 255
 256         pplhdr = page_address(io->header_page);
 257         clear_page(pplhdr);
 258         memset(pplhdr->reserved, 0xff, PPL_HDR_RESERVED);
 259         pplhdr->signature = cpu_to_le32(ppl_conf->signature);
 260
 261         io->seq = atomic64_add_return(1, &ppl_conf->seq);
 262         pplhdr->generation = cpu_to_le64(io->seq);
 263
 264         return io;
 265 }
 266
 267 static int ppl_log_stripe(struct ppl_log *log, struct stripe_head *sh)
 268 {
 269         struct ppl_io_unit *io = log->current_io;
 270         struct ppl_header_entry *e = NULL;
 271         struct ppl_header *pplhdr;
 272         int i;
 273         sector_t data_sector = 0;
 274         int data_disks = 0;
 275         struct r5conf *conf = sh->raid_conf;
 276
 277         pr_debug("%s: stripe: %llu\n", __func__, (unsigned long long)sh->sector);
 278
 279         /* check if current io_unit is full */
 280         if (io && (io->pp_size == log->entry_space ||
 281                    io->entries_count == PPL_HDR_MAX_ENTRIES)) {
 282                 pr_debug("%s: add io_unit blocked by seq: %llu\n",
 283                          __func__, io->seq);
 284                 io = NULL;
 285         }
 286
 287         /* add a new unit if there is none or the current is full */
 288         if (!io) {
 289                 io = ppl_new_iounit(log, sh);
 290                 if (!io)
 291                         return -ENOMEM;
 292                 spin_lock_irq(&log->io_list_lock);
 293                 list_add_tail(&io->log_sibling, &log->io_list);
 294                 spin_unlock_irq(&log->io_list_lock);
 295
 296                 log->current_io = io;
 297         }
 298
 299         for (i = 0; i < sh->disks; i++) {
 300                 struct r5dev *dev = &sh->dev[i];
 301
 302                 if (i != sh->pd_idx && test_bit(R5_Wantwrite, &dev->flags)) {
 303                         if (!data_disks || dev->sector < data_sector)
 304                                 data_sector = dev->sector;
 305                         data_disks++;
 306                 }
 307         }
 308         BUG_ON(!data_disks);
 309
 310         pr_debug("%s: seq: %llu data_sector: %llu data_disks: %d\n", __func__,
 311                  io->seq, (unsigned long long)data_sector, data_disks);
 312
 313         pplhdr = page_address(io->header_page);
 314
 315         if (io->entries_count > 0) {
 316                 struct ppl_header_entry *last =
 317                                 &pplhdr->entries[io->entries_count - 1];
 318                 struct stripe_head *sh_last = list_last_entry(
 319                                 &io->stripe_list, struct stripe_head, log_list);
 320                 u64 data_sector_last = le64_to_cpu(last->data_sector);
 321                 u32 data_size_last = le32_to_cpu(last->data_size);
 322
 323                 /*
 324                  * Check if we can append the stripe to the last entry. It must
 325                  * be just after the last logged stripe and write to the same
 326                  * disks. Use bit shift and logarithm to avoid 64-bit division.
 327                  */
 328                 if ((sh->sector == sh_last->sector + RAID5_STRIPE_SECTORS(conf)) &&
 329                     (data_sector >> ilog2(conf->chunk_sectors) ==
 330                      data_sector_last >> ilog2(conf->chunk_sectors)) &&
 331                     ((data_sector - data_sector_last) * data_disks ==
 332                      data_size_last >> 9))
 333                         e = last;
 334         }
 335
 336         if (!e) {
 337                 e = &pplhdr->entries[io->entries_count++];
 338                 e->data_sector = cpu_to_le64(data_sector);
 339                 e->parity_disk = cpu_to_le32(sh->pd_idx);
 340                 e->checksum = cpu_to_le32(~0);
 341         }
 342
 343         le32_add_cpu(&e->data_size, data_disks << PAGE_SHIFT);
 344
 345         /* don't write any PP if full stripe write */
 346         if (!test_bit(STRIPE_FULL_WRITE, &sh->state)) {
 347                 le32_add_cpu(&e->pp_size, PAGE_SIZE);
 348                 io->pp_size += PAGE_SIZE;
 349                 e->checksum = cpu_to_le32(crc32c_le(le32_to_cpu(e->checksum),
 350                                                     page_address(sh->ppl_page),
 351                                                     PAGE_SIZE));
 352         }
 353
 354         list_add_tail(&sh->log_list, &io->stripe_list);
 355         atomic_inc(&io->pending_stripes);
 356         sh->ppl_io = io;
 357
 358         return 0;
 359 }
 360
 361 int ppl_write_stripe(struct r5conf *conf, struct stripe_head *sh)
 362 {
 363         struct ppl_conf *ppl_conf = conf->log_private;
 364         struct ppl_io_unit *io = sh->ppl_io;
 365         struct ppl_log *log;
 366
 367         if (io || test_bit(STRIPE_SYNCING, &sh->state) || !sh->ppl_page ||
 368             !test_bit(R5_Wantwrite, &sh->dev[sh->pd_idx].flags) ||
 369             !test_bit(R5_Insync, &sh->dev[sh->pd_idx].flags)) {
 370                 clear_bit(STRIPE_LOG_TRAPPED, &sh->state);
 371                 return -EAGAIN;
 372         }
 373
 374         log = &ppl_conf->child_logs[sh->pd_idx];
 375
 376         mutex_lock(&log->io_mutex);
 377
 378         if (!log->rdev || test_bit(Faulty, &log->rdev->flags)) {
 379                 mutex_unlock(&log->io_mutex);
 380                 return -EAGAIN;
 381         }
 382
 383         set_bit(STRIPE_LOG_TRAPPED, &sh->state);
 384         clear_bit(STRIPE_DELAYED, &sh->state);
 385         atomic_inc(&sh->count);
 386
 387         if (ppl_log_stripe(log, sh)) {
 388                 spin_lock_irq(&ppl_conf->no_mem_stripes_lock);
 389                 list_add_tail(&sh->log_list, &ppl_conf->no_mem_stripes);
 390                 spin_unlock_irq(&ppl_conf->no_mem_stripes_lock);
 391         }
 392
 393         mutex_unlock(&log->io_mutex);
 394
 395         return 0;
 396 }
 397
 398 static void ppl_log_endio(struct bio *bio)
 399 {
 400         struct ppl_io_unit *io = bio->bi_private;
 401         struct ppl_log *log = io->log;
 402         struct ppl_conf *ppl_conf = log->ppl_conf;
 403         struct stripe_head *sh, *next;
 404
 405         pr_debug("%s: seq: %llu\n", __func__, io->seq);
 406
 407         if (bio->bi_status)
 408                 md_error(ppl_conf->mddev, log->rdev);
 409
 410         list_for_each_entry_safe(sh, next, &io->stripe_list, log_list) {
 411                 list_del_init(&sh->log_list);
 412
 413                 set_bit(STRIPE_HANDLE, &sh->state);
 414                 raid5_release_stripe(sh);
 415         }
 416 }
 417
 418 static void ppl_submit_iounit_bio(struct ppl_io_unit *io, struct bio *bio)
 419 {
 420         pr_debug("%s: seq: %llu size: %u sector: %llu dev: %pg\n",
 421                  __func__, io->seq, bio->bi_iter.bi_size,
 422                  (unsigned long long)bio->bi_iter.bi_sector,
 423                  bio->bi_bdev);
 424
 425         submit_bio(bio);
 426 }
 427
 428 static void ppl_submit_iounit(struct ppl_io_unit *io)
 429 {
 430         struct ppl_log *log = io->log;
 431         struct ppl_conf *ppl_conf = log->ppl_conf;
 432         struct ppl_header *pplhdr = page_address(io->header_page);
 433         struct bio *bio = &io->bio;
 434         struct stripe_head *sh;
 435         int i;
 436
 437         bio->bi_private = io;
 438
 439         if (!log->rdev || test_bit(Faulty, &log->rdev->flags)) {
 440                 ppl_log_endio(bio);
 441                 return;
 442         }
 443
 444         for (i = 0; i < io->entries_count; i++) {
 445                 struct ppl_header_entry *e = &pplhdr->entries[i];
 446
 447                 pr_debug("%s: seq: %llu entry: %d data_sector: %llu pp_size: %u data_size: %u\n",
 448                          __func__, io->seq, i, le64_to_cpu(e->data_sector),
 449                          le32_to_cpu(e->pp_size), le32_to_cpu(e->data_size));
 450
 451                 e->data_sector = cpu_to_le64(le64_to_cpu(e->data_sector) >>
 452                                              ilog2(ppl_conf->block_size >> 9));
 453                 e->checksum = cpu_to_le32(~le32_to_cpu(e->checksum));
 454         }
 455
 456         pplhdr->entries_count = cpu_to_le32(io->entries_count);
 457         pplhdr->checksum = cpu_to_le32(~crc32c_le(~0, pplhdr, PPL_HEADER_SIZE));
 458
 459         /* Rewind the buffer if current PPL is larger then remaining space */
 460         if (log->use_multippl &&
 461             log->rdev->ppl.sector + log->rdev->ppl.size - log->next_io_sector <
 462             (PPL_HEADER_SIZE + io->pp_size) >> 9)
 463                 log->next_io_sector = log->rdev->ppl.sector;
 464
 465
 466         bio->bi_end_io = ppl_log_endio;
 467         bio->bi_iter.bi_sector = log->next_io_sector;
 468         __bio_add_page(bio, io->header_page, PAGE_SIZE, 0);
 469
 470         pr_debug("%s: log->current_io_sector: %llu\n", __func__,
 471             (unsigned long long)log->next_io_sector);
 472
 473         if (log->use_multippl)
 474                 log->next_io_sector += (PPL_HEADER_SIZE + io->pp_size) >> 9;
 475
 476         WARN_ON(log->disk_flush_bitmap != 0);
 477
 478         list_for_each_entry(sh, &io->stripe_list, log_list) {
 479                 for (i = 0; i < sh->disks; i++) {
 480                         struct r5dev *dev = &sh->dev[i];
 481
 482                         if ((ppl_conf->child_logs[i].wb_cache_on) &&
 483                             (test_bit(R5_Wantwrite, &dev->flags))) {
 484                                 set_bit(i, &log->disk_flush_bitmap);
 485                         }
 486                 }
 487
 488                 /* entries for full stripe writes have no partial parity */
 489                 if (test_bit(STRIPE_FULL_WRITE, &sh->state))
 490                         continue;
 491
 492                 if (!bio_add_page(bio, sh->ppl_page, PAGE_SIZE, 0)) {
 493                         struct bio *prev = bio;
 494
 495                         bio = bio_alloc_bioset(prev->bi_bdev, BIO_MAX_VECS,
 496                                                prev->bi_opf, GFP_NOIO,
 497                                                &ppl_conf->bs);
 498                         bio->bi_iter.bi_sector = bio_end_sector(prev);
 499                         __bio_add_page(bio, sh->ppl_page, PAGE_SIZE, 0);
 500
 501                         bio_chain(bio, prev);
 502                         ppl_submit_iounit_bio(io, prev);
 503                 }
 504         }
 505
 506         ppl_submit_iounit_bio(io, bio);
 507 }
 508
 509 static void ppl_submit_current_io(struct ppl_log *log)
 510 {
 511         struct ppl_io_unit *io;
 512
 513         spin_lock_irq(&log->io_list_lock);
 514
 515         io = list_first_entry_or_null(&log->io_list, struct ppl_io_unit,
 516                                       log_sibling);
 517         if (io && io->submitted)
 518                 io = NULL;
 519
 520         spin_unlock_irq(&log->io_list_lock);
 521
 522         if (io) {
 523                 io->submitted = true;
 524
 525                 if (io == log->current_io)
 526                         log->current_io = NULL;
 527
 528                 ppl_submit_iounit(io);
 529         }
 530 }
 531
 532 void ppl_write_stripe_run(struct r5conf *conf)
 533 {
 534         struct ppl_conf *ppl_conf = conf->log_private;
 535         struct ppl_log *log;
 536         int i;
 537
 538         for (i = 0; i < ppl_conf->count; i++) {
 539                 log = &ppl_conf->child_logs[i];
 540
 541                 mutex_lock(&log->io_mutex);
 542                 ppl_submit_current_io(log);
 543                 mutex_unlock(&log->io_mutex);
 544         }
 545 }
 546
 547 static void ppl_io_unit_finished(struct ppl_io_unit *io)
 548 {
 549         struct ppl_log *log = io->log;
 550         struct ppl_conf *ppl_conf = log->ppl_conf;
 551         struct r5conf *conf = ppl_conf->mddev->private;
 552         unsigned long flags;
 553
 554         pr_debug("%s: seq: %llu\n", __func__, io->seq);
 555
 556         local_irq_save(flags);
 557
 558         spin_lock(&log->io_list_lock);
 559         list_del(&io->log_sibling);
 560         spin_unlock(&log->io_list_lock);
 561
 562         mempool_free(io, &ppl_conf->io_pool);
 563
 564         spin_lock(&ppl_conf->no_mem_stripes_lock);
 565         if (!list_empty(&ppl_conf->no_mem_stripes)) {
 566                 struct stripe_head *sh;
 567
 568                 sh = list_first_entry(&ppl_conf->no_mem_stripes,
 569                                       struct stripe_head, log_list);
 570                 list_del_init(&sh->log_list);
 571                 set_bit(STRIPE_HANDLE, &sh->state);
 572                 raid5_release_stripe(sh);
 573         }
 574         spin_unlock(&ppl_conf->no_mem_stripes_lock);
 575
 576         local_irq_restore(flags);
 577
 578         wake_up(&conf->wait_for_quiescent);
 579 }
 580
 581 static void ppl_flush_endio(struct bio *bio)
 582 {
 583         struct ppl_io_unit *io = bio->bi_private;
 584         struct ppl_log *log = io->log;
 585         struct ppl_conf *ppl_conf = log->ppl_conf;
 586         struct r5conf *conf = ppl_conf->mddev->private;
 587
 588         pr_debug("%s: dev: %pg\n", __func__, bio->bi_bdev);
 589
 590         if (bio->bi_status) {
 591                 struct md_rdev *rdev;
 592
 593                 rcu_read_lock();
 594                 rdev = md_find_rdev_rcu(conf->mddev, bio_dev(bio));
 595                 if (rdev)
 596                         md_error(rdev->mddev, rdev);
 597                 rcu_read_unlock();
 598         }
 599
 600         bio_put(bio);
 601
 602         if (atomic_dec_and_test(&io->pending_flushes)) {
 603                 ppl_io_unit_finished(io);
 604                 md_wakeup_thread(conf->mddev->thread);
 605         }
 606 }
 607
 608 static void ppl_do_flush(struct ppl_io_unit *io)
 609 {
 610         struct ppl_log *log = io->log;
 611         struct ppl_conf *ppl_conf = log->ppl_conf;
 612         struct r5conf *conf = ppl_conf->mddev->private;
 613         int raid_disks = conf->raid_disks;
 614         int flushed_disks = 0;
 615         int i;
 616
 617         atomic_set(&io->pending_flushes, raid_disks);
 618
 619         for_each_set_bit(i, &log->disk_flush_bitmap, raid_disks) {
 620                 struct md_rdev *rdev;
 621                 struct block_device *bdev = NULL;
 622
 623                 rdev = conf->disks[i].rdev;
 624                 if (rdev && !test_bit(Faulty, &rdev->flags))
 625                         bdev = rdev->bdev;
 626
 627                 if (bdev) {
 628                         struct bio *bio;
 629
 630                         bio = bio_alloc_bioset(bdev, 0,
 631                                                REQ_OP_WRITE | REQ_PREFLUSH,
 632                                                GFP_NOIO, &ppl_conf->flush_bs);
 633                         bio->bi_private = io;
 634                         bio->bi_end_io = ppl_flush_endio;
 635
 636                         pr_debug("%s: dev: %ps\n", __func__, bio->bi_bdev);
 637
 638                         submit_bio(bio);
 639                         flushed_disks++;
 640                 }
 641         }
 642
 643         log->disk_flush_bitmap = 0;
 644
 645         for (i = flushed_disks ; i < raid_disks; i++) {
 646                 if (atomic_dec_and_test(&io->pending_flushes))
 647                         ppl_io_unit_finished(io);
 648         }
 649 }
 650
 651 static inline bool ppl_no_io_unit_submitted(struct r5conf *conf,
 652                                             struct ppl_log *log)
 653 {
 654         struct ppl_io_unit *io;
 655
 656         io = list_first_entry_or_null(&log->io_list, struct ppl_io_unit,
 657                                       log_sibling);
 658
 659         return !io || !io->submitted;
 660 }
 661
 662 void ppl_quiesce(struct r5conf *conf, int quiesce)
 663 {
 664         struct ppl_conf *ppl_conf = conf->log_private;
 665         int i;
 666
 667         if (quiesce) {
 668                 for (i = 0; i < ppl_conf->count; i++) {
 669                         struct ppl_log *log = &ppl_conf->child_logs[i];
 670
 671                         spin_lock_irq(&log->io_list_lock);
 672                         wait_event_lock_irq(conf->wait_for_quiescent,
 673                                             ppl_no_io_unit_submitted(conf, log),
 674                                             log->io_list_lock);
 675                         spin_unlock_irq(&log->io_list_lock);
 676                 }
 677         }
 678 }
 679
 680 int ppl_handle_flush_request(struct bio *bio)
 681 {
 682         if (bio->bi_iter.bi_size == 0) {
 683                 bio_endio(bio);
 684                 return 0;
 685         }
 686         bio->bi_opf &= ~REQ_PREFLUSH;
 687         return -EAGAIN;
 688 }
 689
 690 void ppl_stripe_write_finished(struct stripe_head *sh)
 691 {
 692         struct ppl_io_unit *io;
 693
 694         io = sh->ppl_io;
 695         sh->ppl_io = NULL;
 696
 697         if (io && atomic_dec_and_test(&io->pending_stripes)) {
 698                 if (io->log->disk_flush_bitmap)
 699                         ppl_do_flush(io);
 700                 else
 701                         ppl_io_unit_finished(io);
 702         }
 703 }
 704
 705 static void ppl_xor(int size, struct page *page1, struct page *page2)
 706 {
 707         struct async_submit_ctl submit;
 708         struct dma_async_tx_descriptor *tx;
 709         struct page *xor_srcs[] = { page1, page2 };
 710
 711         init_async_submit(&submit, ASYNC_TX_ACK|ASYNC_TX_XOR_DROP_DST,
 712                           NULL, NULL, NULL, NULL);
 713         tx = async_xor(page1, xor_srcs, 0, 2, size, &submit);
 714
 715         async_tx_quiesce(&tx);
 716 }
 717
 718 /*
 719  * PPL recovery strategy: xor partial parity and data from all modified data
 720  * disks within a stripe and write the result as the new stripe parity. If all
 721  * stripe data disks are modified (full stripe write), no partial parity is
 722  * available, so just xor the data disks.
 723  *
 724  * Recovery of a PPL entry shall occur only if all modified data disks are
 725  * available and read from all of them succeeds.
 726  *
 727  * A PPL entry applies to a stripe, partial parity size for an entry is at most
 728  * the size of the chunk. Examples of possible cases for a single entry:
 729  *
 730  * case 0: single data disk write:
 731  *   data0    data1    data2     ppl        parity
 732  * +--------+--------+--------+           +--------------------+
 733  * | ------ | ------ | ------ | +----+    | (no change)        |
 734  * | ------ | -data- | ------ | | pp | -> | data1 ^ pp         |
 735  * | ------ | -data- | ------ | | pp | -> | data1 ^ pp         |
 736  * | ------ | ------ | ------ | +----+    | (no change)        |
 737  * +--------+--------+--------+           +--------------------+
 738  * pp_size = data_size
 739  *
 740  * case 1: more than one data disk write:
 741  *   data0    data1    data2     ppl        parity
 742  * +--------+--------+--------+           +--------------------+
 743  * | ------ | ------ | ------ | +----+    | (no change)        |
 744  * | -data- | -data- | ------ | | pp | -> | data0 ^ data1 ^ pp |
 745  * | -data- | -data- | ------ | | pp | -> | data0 ^ data1 ^ pp |
 746  * | ------ | ------ | ------ | +----+    | (no change)        |
 747  * +--------+--------+--------+           +--------------------+
 748  * pp_size = data_size / modified_data_disks
 749  *
 750  * case 2: write to all data disks (also full stripe write):
 751  *   data0    data1    data2                parity
 752  * +--------+--------+--------+           +--------------------+
 753  * | ------ | ------ | ------ |           | (no change)        |
 754  * | -data- | -data- | -data- | --------> | xor all data       |
 755  * | ------ | ------ | ------ | --------> | (no change)        |
 756  * | ------ | ------ | ------ |           | (no change)        |
 757  * +--------+--------+--------+           +--------------------+
 758  * pp_size = 0
 759  *
 760  * The following cases are possible only in other implementations. The recovery
 761  * code can handle them, but they are not generated at runtime because they can
 762  * be reduced to cases 0, 1 and 2:
 763  *
 764  * case 3:
 765  *   data0    data1    data2     ppl        parity
 766  * +--------+--------+--------+ +----+    +--------------------+
 767  * | ------ | -data- | -data- | | pp |    | data1 ^ data2 ^ pp |
 768  * | ------ | -data- | -data- | | pp | -> | data1 ^ data2 ^ pp |
 769  * | -data- | -data- | -data- | | -- | -> | xor all data       |
 770  * | -data- | -data- | ------ | | pp |    | data0 ^ data1 ^ pp |
 771  * +--------+--------+--------+ +----+    +--------------------+
 772  * pp_size = chunk_size
 773  *
 774  * case 4:
 775  *   data0    data1    data2     ppl        parity
 776  * +--------+--------+--------+ +----+    +--------------------+
 777  * | ------ | -data- | ------ | | pp |    | data1 ^ pp         |
 778  * | ------ | ------ | ------ | | -- | -> | (no change)        |
 779  * | ------ | ------ | ------ | | -- | -> | (no change)        |
 780  * | -data- | ------ | ------ | | pp |    | data0 ^ pp         |
 781  * +--------+--------+--------+ +----+    +--------------------+
 782  * pp_size = chunk_size
 783  */
 784 static int ppl_recover_entry(struct ppl_log *log, struct ppl_header_entry *e,
 785                              sector_t ppl_sector)
 786 {
 787         struct ppl_conf *ppl_conf = log->ppl_conf;
 788         struct mddev *mddev = ppl_conf->mddev;
 789         struct r5conf *conf = mddev->private;
 790         int block_size = ppl_conf->block_size;
 791         struct page *page1;
 792         struct page *page2;
 793         sector_t r_sector_first;
 794         sector_t r_sector_last;
 795         int strip_sectors;
 796         int data_disks;
 797         int i;
 798         int ret = 0;
 799         unsigned int pp_size = le32_to_cpu(e->pp_size);
 800         unsigned int data_size = le32_to_cpu(e->data_size);
 801
 802         page1 = alloc_page(GFP_KERNEL);
 803         page2 = alloc_page(GFP_KERNEL);
 804
 805         if (!page1 || !page2) {
 806                 ret = -ENOMEM;
 807                 goto out;
 808         }
 809
 810         r_sector_first = le64_to_cpu(e->data_sector) * (block_size >> 9);
 811
 812         if ((pp_size >> 9) < conf->chunk_sectors) {
 813                 if (pp_size > 0) {
 814                         data_disks = data_size / pp_size;
 815                         strip_sectors = pp_size >> 9;
 816                 } else {
 817                         data_disks = conf->raid_disks - conf->max_degraded;
 818                         strip_sectors = (data_size >> 9) / data_disks;
 819                 }
 820                 r_sector_last = r_sector_first +
 821                                 (data_disks - 1) * conf->chunk_sectors +
 822                                 strip_sectors;
 823         } else {
 824                 data_disks = conf->raid_disks - conf->max_degraded;
 825                 strip_sectors = conf->chunk_sectors;
 826                 r_sector_last = r_sector_first + (data_size >> 9);
 827         }
 828
 829         pr_debug("%s: array sector first: %llu last: %llu\n", __func__,
 830                  (unsigned long long)r_sector_first,
 831                  (unsigned long long)r_sector_last);
 832
 833         /* if start and end is 4k aligned, use a 4k block */
 834         if (block_size == 512 &&
 835             (r_sector_first & (RAID5_STRIPE_SECTORS(conf) - 1)) == 0 &&
 836             (r_sector_last & (RAID5_STRIPE_SECTORS(conf) - 1)) == 0)
 837                 block_size = RAID5_STRIPE_SIZE(conf);
 838
 839         /* iterate through blocks in strip */
 840         for (i = 0; i < strip_sectors; i += (block_size >> 9)) {
 841                 bool update_parity = false;
 842                 sector_t parity_sector;
 843                 struct md_rdev *parity_rdev;
 844                 struct stripe_head sh;
 845                 int disk;
 846                 int indent = 0;
 847
 848                 pr_debug("%s:%*s iter %d start\n", __func__, indent, "", i);
 849                 indent += 2;
 850
 851                 memset(page_address(page1), 0, PAGE_SIZE);
 852
 853                 /* iterate through data member disks */
 854                 for (disk = 0; disk < data_disks; disk++) {
 855                         int dd_idx;
 856                         struct md_rdev *rdev;
 857                         sector_t sector;
 858                         sector_t r_sector = r_sector_first + i +
 859                                             (disk * conf->chunk_sectors);
 860
 861                         pr_debug("%s:%*s data member disk %d start\n",
 862                                  __func__, indent, "", disk);
 863                         indent += 2;
 864
 865                         if (r_sector >= r_sector_last) {
 866                                 pr_debug("%s:%*s array sector %llu doesn't need parity update\n",
 867                                          __func__, indent, "",
 868                                          (unsigned long long)r_sector);
 869                                 indent -= 2;
 870                                 continue;
 871                         }
 872
 873                         update_parity = true;
 874
 875                         /* map raid sector to member disk */
 876                         sector = raid5_compute_sector(conf, r_sector, 0,
 877                                                       &dd_idx, NULL);
 878                         pr_debug("%s:%*s processing array sector %llu => data member disk %d, sector %llu\n",
 879                                  __func__, indent, "",
 880                                  (unsigned long long)r_sector, dd_idx,
 881                                  (unsigned long long)sector);
 882
 883                         rdev = conf->disks[dd_idx].rdev;
 884                         if (!rdev || (!test_bit(In_sync, &rdev->flags) &&
 885                                       sector >= rdev->recovery_offset)) {
 886                                 pr_debug("%s:%*s data member disk %d missing\n",
 887                                          __func__, indent, "", dd_idx);
 888                                 update_parity = false;
 889                                 break;
 890                         }
 891
 892                         pr_debug("%s:%*s reading data member disk %pg sector %llu\n",
 893                                  __func__, indent, "", rdev->bdev,
 894                                  (unsigned long long)sector);
 895                         if (!sync_page_io(rdev, sector, block_size, page2,
 896                                         REQ_OP_READ, false)) {
 897                                 md_error(mddev, rdev);
 898                                 pr_debug("%s:%*s read failed!\n", __func__,
 899                                          indent, "");
 900                                 ret = -EIO;
 901                                 goto out;
 902                         }
 903
 904                         ppl_xor(block_size, page1, page2);
 905
 906                         indent -= 2;
 907                 }
 908
 909                 if (!update_parity)
 910                         continue;
 911
 912                 if (pp_size > 0) {
 913                         pr_debug("%s:%*s reading pp disk sector %llu\n",
 914                                  __func__, indent, "",
 915                                  (unsigned long long)(ppl_sector + i));
 916                         if (!sync_page_io(log->rdev,
 917                                         ppl_sector - log->rdev->data_offset + i,
 918                                         block_size, page2, REQ_OP_READ,
 919                                         false)) {
 920                                 pr_debug("%s:%*s read failed!\n", __func__,
 921                                          indent, "");
 922                                 md_error(mddev, log->rdev);
 923                                 ret = -EIO;
 924                                 goto out;
 925                         }
 926
 927                         ppl_xor(block_size, page1, page2);
 928                 }
 929
 930                 /* map raid sector to parity disk */
 931                 parity_sector = raid5_compute_sector(conf, r_sector_first + i,
 932                                 0, &disk, &sh);
 933                 BUG_ON(sh.pd_idx != le32_to_cpu(e->parity_disk));
 934
 935                 parity_rdev = conf->disks[sh.pd_idx].rdev;
 936
 937                 BUG_ON(parity_rdev->bdev->bd_dev != log->rdev->bdev->bd_dev);
 938                 pr_debug("%s:%*s write parity at sector %llu, disk %pg\n",
 939                          __func__, indent, "",
 940                          (unsigned long long)parity_sector,
 941                          parity_rdev->bdev);
 942                 if (!sync_page_io(parity_rdev, parity_sector, block_size,
 943                                   page1, REQ_OP_WRITE, false)) {
 944                         pr_debug("%s:%*s parity write error!\n", __func__,
 945                                  indent, "");
 946                         md_error(mddev, parity_rdev);
 947                         ret = -EIO;
 948                         goto out;
 949                 }
 950         }
 951 out:
 952         if (page1)
 953                 __free_page(page1);
 954         if (page2)
 955                 __free_page(page2);
 956         return ret;
 957 }
 958
 959 static int ppl_recover(struct ppl_log *log, struct ppl_header *pplhdr,
 960                        sector_t offset)
 961 {
 962         struct ppl_conf *ppl_conf = log->ppl_conf;
 963         struct md_rdev *rdev = log->rdev;
 964         struct mddev *mddev = rdev->mddev;
 965         sector_t ppl_sector = rdev->ppl.sector + offset +
 966                               (PPL_HEADER_SIZE >> 9);
 967         struct page *page;
 968         int i;
 969         int ret = 0;
 970
 971         page = alloc_page(GFP_KERNEL);
 972         if (!page)
 973                 return -ENOMEM;
 974
 975         /* iterate through all PPL entries saved */
 976         for (i = 0; i < le32_to_cpu(pplhdr->entries_count); i++) {
 977                 struct ppl_header_entry *e = &pplhdr->entries[i];
 978                 u32 pp_size = le32_to_cpu(e->pp_size);
 979                 sector_t sector = ppl_sector;
 980                 int ppl_entry_sectors = pp_size >> 9;
 981                 u32 crc, crc_stored;
 982
 983                 pr_debug("%s: disk: %d entry: %d ppl_sector: %llu pp_size: %u\n",
 984                          __func__, rdev->raid_disk, i,
 985                          (unsigned long long)ppl_sector, pp_size);
 986
 987                 crc = ~0;
 988                 crc_stored = le32_to_cpu(e->checksum);
 989
 990                 /* read parial parity for this entry and calculate its checksum */
 991                 while (pp_size) {
 992                         int s = pp_size > PAGE_SIZE ? PAGE_SIZE : pp_size;
 993
 994                         if (!sync_page_io(rdev, sector - rdev->data_offset,
 995                                         s, page, REQ_OP_READ, false)) {
 996                                 md_error(mddev, rdev);
 997                                 ret = -EIO;
 998                                 goto out;
 999                         }
1000
1001                         crc = crc32c_le(crc, page_address(page), s);
1002
1003                         pp_size -= s;
1004                         sector += s >> 9;
1005                 }
1006
1007                 crc = ~crc;
1008
1009                 if (crc != crc_stored) {
1010                         /*
1011                          * Don't recover this entry if the checksum does not
1012                          * match, but keep going and try to recover other
1013                          * entries.
1014                          */
1015                         pr_debug("%s: ppl entry crc does not match: stored: 0x%x calculated: 0x%x\n",
1016                                  __func__, crc_stored, crc);
1017                         ppl_conf->mismatch_count++;
1018                 } else {
1019                         ret = ppl_recover_entry(log, e, ppl_sector);
1020                         if (ret)
1021                                 goto out;
1022                         ppl_conf->recovered_entries++;
1023                 }
1024
1025                 ppl_sector += ppl_entry_sectors;
1026         }
1027
1028         /* flush the disk cache after recovery if necessary */
1029         ret = blkdev_issue_flush(rdev->bdev);
1030 out:
1031         __free_page(page);
1032         return ret;
1033 }
1034
1035 static int ppl_write_empty_header(struct ppl_log *log)
1036 {
1037         struct page *page;
1038         struct ppl_header *pplhdr;
1039         struct md_rdev *rdev = log->rdev;
1040         int ret = 0;
1041
1042         pr_debug("%s: disk: %d ppl_sector: %llu\n", __func__,
1043                  rdev->raid_disk, (unsigned long long)rdev->ppl.sector);
1044
1045         page = alloc_page(GFP_NOIO | __GFP_ZERO);
1046         if (!page)
1047                 return -ENOMEM;
1048
1049         pplhdr = page_address(page);
1050         /* zero out PPL space to avoid collision with old PPLs */
1051         blkdev_issue_zeroout(rdev->bdev, rdev->ppl.sector,
1052                             log->rdev->ppl.size, GFP_NOIO, 0);
1053         memset(pplhdr->reserved, 0xff, PPL_HDR_RESERVED);
1054         pplhdr->signature = cpu_to_le32(log->ppl_conf->signature);
1055         pplhdr->checksum = cpu_to_le32(~crc32c_le(~0, pplhdr, PAGE_SIZE));
1056
1057         if (!sync_page_io(rdev, rdev->ppl.sector - rdev->data_offset,
1058                           PPL_HEADER_SIZE, page, REQ_OP_WRITE | REQ_SYNC |
1059                           REQ_FUA, false)) {
1060                 md_error(rdev->mddev, rdev);
1061                 ret = -EIO;
1062         }
1063
1064         __free_page(page);
1065         return ret;
1066 }
1067
1068 static int ppl_load_distributed(struct ppl_log *log)
1069 {
1070         struct ppl_conf *ppl_conf = log->ppl_conf;
1071         struct md_rdev *rdev = log->rdev;
1072         struct mddev *mddev = rdev->mddev;
1073         struct page *page, *page2;
1074         struct ppl_header *pplhdr = NULL, *prev_pplhdr = NULL;
1075         u32 crc, crc_stored;
1076         u32 signature;
1077         int ret = 0, i;
1078         sector_t pplhdr_offset = 0, prev_pplhdr_offset = 0;
1079
1080         pr_debug("%s: disk: %d\n", __func__, rdev->raid_disk);
1081         /* read PPL headers, find the recent one */
1082         page = alloc_page(GFP_KERNEL);
1083         if (!page)
1084                 return -ENOMEM;
1085
1086         page2 = alloc_page(GFP_KERNEL);
1087         if (!page2) {
1088                 __free_page(page);
1089                 return -ENOMEM;
1090         }
1091
1092         /* searching ppl area for latest ppl */
1093         while (pplhdr_offset < rdev->ppl.size - (PPL_HEADER_SIZE >> 9)) {
1094                 if (!sync_page_io(rdev,
1095                                   rdev->ppl.sector - rdev->data_offset +
1096                                   pplhdr_offset, PAGE_SIZE, page, REQ_OP_READ,
1097                                   false)) {
1098                         md_error(mddev, rdev);
1099                         ret = -EIO;
1100                         /* if not able to read - don't recover any PPL */
1101                         pplhdr = NULL;
1102                         break;
1103                 }
1104                 pplhdr = page_address(page);
1105
1106                 /* check header validity */
1107                 crc_stored = le32_to_cpu(pplhdr->checksum);
1108                 pplhdr->checksum = 0;
1109                 crc = ~crc32c_le(~0, pplhdr, PAGE_SIZE);
1110
1111                 if (crc_stored != crc) {
1112                         pr_debug("%s: ppl header crc does not match: stored: 0x%x calculated: 0x%x (offset: %llu)\n",
1113                                  __func__, crc_stored, crc,
1114                                  (unsigned long long)pplhdr_offset);
1115                         pplhdr = prev_pplhdr;
1116                         pplhdr_offset = prev_pplhdr_offset;
1117                         break;
1118                 }
1119
1120                 signature = le32_to_cpu(pplhdr->signature);
1121
1122                 if (mddev->external) {
1123                         /*
1124                          * For external metadata the header signature is set and
1125                          * validated in userspace.
1126                          */
1127                         ppl_conf->signature = signature;
1128                 } else if (ppl_conf->signature != signature) {
1129                         pr_debug("%s: ppl header signature does not match: stored: 0x%x configured: 0x%x (offset: %llu)\n",
1130                                  __func__, signature, ppl_conf->signature,
1131                                  (unsigned long long)pplhdr_offset);
1132                         pplhdr = prev_pplhdr;
1133                         pplhdr_offset = prev_pplhdr_offset;
1134                         break;
1135                 }
1136
1137                 if (prev_pplhdr && le64_to_cpu(prev_pplhdr->generation) >
1138                     le64_to_cpu(pplhdr->generation)) {
1139                         /* previous was newest */
1140                         pplhdr = prev_pplhdr;
1141                         pplhdr_offset = prev_pplhdr_offset;
1142                         break;
1143                 }
1144
1145                 prev_pplhdr_offset = pplhdr_offset;
1146                 prev_pplhdr = pplhdr;
1147
1148                 swap(page, page2);
1149
1150                 /* calculate next potential ppl offset */
1151                 for (i = 0; i < le32_to_cpu(pplhdr->entries_count); i++)
1152                         pplhdr_offset +=
1153                             le32_to_cpu(pplhdr->entries[i].pp_size) >> 9;
1154                 pplhdr_offset += PPL_HEADER_SIZE >> 9;
1155         }
1156
1157         /* no valid ppl found */
1158         if (!pplhdr)
1159                 ppl_conf->mismatch_count++;
1160         else
1161                 pr_debug("%s: latest PPL found at offset: %llu, with generation: %llu\n",
1162                     __func__, (unsigned long long)pplhdr_offset,
1163                     le64_to_cpu(pplhdr->generation));
1164
1165         /* attempt to recover from log if we are starting a dirty array */
1166         if (pplhdr && !mddev->pers && mddev->recovery_cp != MaxSector)
1167                 ret = ppl_recover(log, pplhdr, pplhdr_offset);
1168
1169         /* write empty header if we are starting the array */
1170         if (!ret && !mddev->pers)
1171                 ret = ppl_write_empty_header(log);
1172
1173         __free_page(page);
1174         __free_page(page2);
1175
1176         pr_debug("%s: return: %d mismatch_count: %d recovered_entries: %d\n",
1177                  __func__, ret, ppl_conf->mismatch_count,
1178                  ppl_conf->recovered_entries);
1179         return ret;
1180 }
1181
1182 static int ppl_load(struct ppl_conf *ppl_conf)
1183 {
1184         int ret = 0;
1185         u32 signature = 0;
1186         bool signature_set = false;
1187         int i;
1188
1189         for (i = 0; i < ppl_conf->count; i++) {
1190                 struct ppl_log *log = &ppl_conf->child_logs[i];
1191
1192                 /* skip missing drive */
1193                 if (!log->rdev)
1194                         continue;
1195
1196                 ret = ppl_load_distributed(log);
1197                 if (ret)
1198                         break;
1199
1200                 /*
1201                  * For external metadata we can't check if the signature is
1202                  * correct on a single drive, but we can check if it is the same
1203                  * on all drives.
1204                  */
1205                 if (ppl_conf->mddev->external) {
1206                         if (!signature_set) {
1207                                 signature = ppl_conf->signature;
1208                                 signature_set = true;
1209                         } else if (signature != ppl_conf->signature) {
1210                                 pr_warn("md/raid:%s: PPL header signature does not match on all member drives\n",
1211                                         mdname(ppl_conf->mddev));
1212                                 ret = -EINVAL;
1213                                 break;
1214                         }
1215                 }
1216         }
1217
1218         pr_debug("%s: return: %d mismatch_count: %d recovered_entries: %d\n",
1219                  __func__, ret, ppl_conf->mismatch_count,
1220                  ppl_conf->recovered_entries);
1221         return ret;
1222 }
1223
1224 static void __ppl_exit_log(struct ppl_conf *ppl_conf)
1225 {
1226         clear_bit(MD_HAS_PPL, &ppl_conf->mddev->flags);
1227         clear_bit(MD_HAS_MULTIPLE_PPLS, &ppl_conf->mddev->flags);
1228
1229         kfree(ppl_conf->child_logs);
1230
1231         bioset_exit(&ppl_conf->bs);
1232         bioset_exit(&ppl_conf->flush_bs);
1233         mempool_exit(&ppl_conf->io_pool);
1234         kmem_cache_destroy(ppl_conf->io_kc);
1235
1236         kfree(ppl_conf);
1237 }
1238
1239 void ppl_exit_log(struct r5conf *conf)
1240 {
1241         struct ppl_conf *ppl_conf = conf->log_private;
1242
1243         if (ppl_conf) {
1244                 __ppl_exit_log(ppl_conf);
1245                 conf->log_private = NULL;
1246         }
1247 }
1248
1249 static int ppl_validate_rdev(struct md_rdev *rdev)
1250 {
1251         int ppl_data_sectors;
1252         int ppl_size_new;
1253
1254         /*
1255          * The configured PPL size must be enough to store
1256          * the header and (at the very least) partial parity
1257          * for one stripe. Round it down to ensure the data
1258          * space is cleanly divisible by stripe size.
1259          */
1260         ppl_data_sectors = rdev->ppl.size - (PPL_HEADER_SIZE >> 9);
1261
1262         if (ppl_data_sectors > 0)
1263                 ppl_data_sectors = rounddown(ppl_data_sectors,
1264                                 RAID5_STRIPE_SECTORS((struct r5conf *)rdev->mddev->private));
1265
1266         if (ppl_data_sectors <= 0) {
1267                 pr_warn("md/raid:%s: PPL space too small on %pg\n",
1268                         mdname(rdev->mddev), rdev->bdev);
1269                 return -ENOSPC;
1270         }
1271
1272         ppl_size_new = ppl_data_sectors + (PPL_HEADER_SIZE >> 9);
1273
1274         if ((rdev->ppl.sector < rdev->data_offset &&
1275              rdev->ppl.sector + ppl_size_new > rdev->data_offset) ||
1276             (rdev->ppl.sector >= rdev->data_offset &&
1277              rdev->data_offset + rdev->sectors > rdev->ppl.sector)) {
1278                 pr_warn("md/raid:%s: PPL space overlaps with data on %pg\n",
1279                         mdname(rdev->mddev), rdev->bdev);
1280                 return -EINVAL;
1281         }
1282
1283         if (!rdev->mddev->external &&
1284             ((rdev->ppl.offset > 0 && rdev->ppl.offset < (rdev->sb_size >> 9)) ||
1285              (rdev->ppl.offset <= 0 && rdev->ppl.offset + ppl_size_new > 0))) {
1286                 pr_warn("md/raid:%s: PPL space overlaps with superblock on %pg\n",
1287                         mdname(rdev->mddev), rdev->bdev);
1288                 return -EINVAL;
1289         }
1290
1291         rdev->ppl.size = ppl_size_new;
1292
1293         return 0;
1294 }
1295
1296 static void ppl_init_child_log(struct ppl_log *log, struct md_rdev *rdev)
1297 {
1298         if ((rdev->ppl.size << 9) >= (PPL_SPACE_SIZE +
1299                                       PPL_HEADER_SIZE) * 2) {
1300                 log->use_multippl = true;
1301                 set_bit(MD_HAS_MULTIPLE_PPLS,
1302                         &log->ppl_conf->mddev->flags);
1303                 log->entry_space = PPL_SPACE_SIZE;
1304         } else {
1305                 log->use_multippl = false;
1306                 log->entry_space = (log->rdev->ppl.size << 9) -
1307                                    PPL_HEADER_SIZE;
1308         }
1309         log->next_io_sector = rdev->ppl.sector;
1310
1311         if (bdev_write_cache(rdev->bdev))
1312                 log->wb_cache_on = true;
1313 }
1314
1315 int ppl_init_log(struct r5conf *conf)
1316 {
1317         struct ppl_conf *ppl_conf;
1318         struct mddev *mddev = conf->mddev;
1319         int ret = 0;
1320         int max_disks;
1321         int i;
1322
1323         pr_debug("md/raid:%s: enabling distributed Partial Parity Log\n",
1324                  mdname(conf->mddev));
1325
1326         if (PAGE_SIZE != 4096)
1327                 return -EINVAL;
1328
1329         if (mddev->level != 5) {
1330                 pr_warn("md/raid:%s PPL is not compatible with raid level %d\n",
1331                         mdname(mddev), mddev->level);
1332                 return -EINVAL;
1333         }
1334
1335         if (mddev->bitmap_info.file || mddev->bitmap_info.offset) {
1336                 pr_warn("md/raid:%s PPL is not compatible with bitmap\n",
1337                         mdname(mddev));
1338                 return -EINVAL;
1339         }
1340
1341         if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
1342                 pr_warn("md/raid:%s PPL is not compatible with journal\n",
1343                         mdname(mddev));
1344                 return -EINVAL;
1345         }
1346
1347         max_disks = sizeof_field(struct ppl_log, disk_flush_bitmap) *
1348                 BITS_PER_BYTE;
1349         if (conf->raid_disks > max_disks) {
1350                 pr_warn("md/raid:%s PPL doesn't support over %d disks in the array\n",
1351                         mdname(mddev), max_disks);
1352                 return -EINVAL;
1353         }
1354
1355         ppl_conf = kzalloc(sizeof(struct ppl_conf), GFP_KERNEL);
1356         if (!ppl_conf)
1357                 return -ENOMEM;
1358
1359         ppl_conf->mddev = mddev;
1360
1361         ppl_conf->io_kc = KMEM_CACHE(ppl_io_unit, 0);
1362         if (!ppl_conf->io_kc) {
1363                 ret = -ENOMEM;
1364                 goto err;
1365         }
1366
1367         ret = mempool_init(&ppl_conf->io_pool, conf->raid_disks, ppl_io_pool_alloc,
1368                            ppl_io_pool_free, ppl_conf->io_kc);
1369         if (ret)
1370                 goto err;
1371
1372         ret = bioset_init(&ppl_conf->bs, conf->raid_disks, 0, BIOSET_NEED_BVECS);
1373         if (ret)
1374                 goto err;
1375
1376         ret = bioset_init(&ppl_conf->flush_bs, conf->raid_disks, 0, 0);
1377         if (ret)
1378                 goto err;
1379
1380         ppl_conf->count = conf->raid_disks;
1381         ppl_conf->child_logs = kcalloc(ppl_conf->count, sizeof(struct ppl_log),
1382                                        GFP_KERNEL);
1383         if (!ppl_conf->child_logs) {
1384                 ret = -ENOMEM;
1385                 goto err;
1386         }
1387
1388         atomic64_set(&ppl_conf->seq, 0);
1389         INIT_LIST_HEAD(&ppl_conf->no_mem_stripes);
1390         spin_lock_init(&ppl_conf->no_mem_stripes_lock);
1391
1392         if (!mddev->external) {
1393                 ppl_conf->signature = ~crc32c_le(~0, mddev->uuid, sizeof(mddev->uuid));
1394                 ppl_conf->block_size = 512;
1395         } else {
1396                 ppl_conf->block_size = queue_logical_block_size(mddev->queue);
1397         }
1398
1399         for (i = 0; i < ppl_conf->count; i++) {
1400                 struct ppl_log *log = &ppl_conf->child_logs[i];
1401                 struct md_rdev *rdev = conf->disks[i].rdev;
1402
1403                 mutex_init(&log->io_mutex);
1404                 spin_lock_init(&log->io_list_lock);
1405                 INIT_LIST_HEAD(&log->io_list);
1406
1407                 log->ppl_conf = ppl_conf;
1408                 log->rdev = rdev;
1409
1410                 if (rdev) {
1411                         ret = ppl_validate_rdev(rdev);
1412                         if (ret)
1413                                 goto err;
1414
1415                         ppl_init_child_log(log, rdev);
1416                 }
1417         }
1418
1419         /* load and possibly recover the logs from the member disks */
1420         ret = ppl_load(ppl_conf);
1421
1422         if (ret) {
1423                 goto err;
1424         } else if (!mddev->pers && mddev->recovery_cp == 0 &&
1425                    ppl_conf->recovered_entries > 0 &&
1426                    ppl_conf->mismatch_count == 0) {
1427                 /*
1428                  * If we are starting a dirty array and the recovery succeeds
1429                  * without any issues, set the array as clean.
1430                  */
1431                 mddev->recovery_cp = MaxSector;
1432                 set_bit(MD_SB_CHANGE_CLEAN, &mddev->sb_flags);
1433         } else if (mddev->pers && ppl_conf->mismatch_count > 0) {
1434                 /* no mismatch allowed when enabling PPL for a running array */
1435                 ret = -EINVAL;
1436                 goto err;
1437         }
1438
1439         conf->log_private = ppl_conf;
1440         set_bit(MD_HAS_PPL, &ppl_conf->mddev->flags);
1441
1442         return 0;
1443 err:
1444         __ppl_exit_log(ppl_conf);
1445         return ret;
1446 }
1447
1448 int ppl_modify_log(struct r5conf *conf, struct md_rdev *rdev, bool add)
1449 {
1450         struct ppl_conf *ppl_conf = conf->log_private;
1451         struct ppl_log *log;
1452         int ret = 0;
1453
1454         if (!rdev)
1455                 return -EINVAL;
1456
1457         pr_debug("%s: disk: %d operation: %s dev: %pg\n",
1458                  __func__, rdev->raid_disk, add ? "add" : "remove",
1459                  rdev->bdev);
1460
1461         if (rdev->raid_disk < 0)
1462                 return 0;
1463
1464         if (rdev->raid_disk >= ppl_conf->count)
1465                 return -ENODEV;
1466
1467         log = &ppl_conf->child_logs[rdev->raid_disk];
1468
1469         mutex_lock(&log->io_mutex);
1470         if (add) {
1471                 ret = ppl_validate_rdev(rdev);
1472                 if (!ret) {
1473                         log->rdev = rdev;
1474                         ret = ppl_write_empty_header(log);
1475                         ppl_init_child_log(log, rdev);
1476                 }
1477         } else {
1478                 log->rdev = NULL;
1479         }
1480         mutex_unlock(&log->io_mutex);
1481
1482         return ret;
1483 }
1484
1485 static ssize_t
1486 ppl_write_hint_show(struct mddev *mddev, char *buf)
1487 {
1488         return sprintf(buf, "%d\n", 0);
1489 }
1490
1491 static ssize_t
1492 ppl_write_hint_store(struct mddev *mddev, const char *page, size_t len)
1493 {
1494         struct r5conf *conf;
1495         int err = 0;
1496         unsigned short new;
1497
1498         if (len >= PAGE_SIZE)
1499                 return -EINVAL;
1500         if (kstrtou16(page, 10, &new))
1501                 return -EINVAL;
1502
1503         err = mddev_lock(mddev);
1504         if (err)
1505                 return err;
1506
1507         conf = mddev->private;
1508         if (!conf)
1509                 err = -ENODEV;
1510         else if (!raid5_has_ppl(conf) || !conf->log_private)
1511                 err = -EINVAL;
1512
1513         mddev_unlock(mddev);
1514
1515         return err ?: len;
1516 }
1517
1518 struct md_sysfs_entry
1519 ppl_write_hint = __ATTR(ppl_write_hint, S_IRUGO | S_IWUSR,
1520                         ppl_write_hint_show,
1521                         ppl_write_hint_store);