fs/nilfs2/segbuf.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * segbuf.c - NILFS segment buffer
   4  *
   5  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   6  *
   7  * Written by Ryusuke Konishi.
   8  *
   9  */
  10
  11 #include <linux/buffer_head.h>
  12 #include <linux/writeback.h>
  13 #include <linux/crc32.h>
  14 #include <linux/backing-dev.h>
  15 #include <linux/slab.h>
  16 #include "page.h"
  17 #include "segbuf.h"
  18
  19
  20 struct nilfs_write_info {
  21         struct the_nilfs       *nilfs;
  22         struct bio             *bio;
  23         int                     start, end; /* The region to be submitted */
  24         int                     rest_blocks;
  25         int                     max_pages;
  26         int                     nr_vecs;
  27         sector_t                blocknr;
  28 };
  29
  30 static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
  31                               struct the_nilfs *nilfs);
  32 static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf);
  33
  34 struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *sb)
  35 {
  36         struct nilfs_segment_buffer *segbuf;
  37
  38         segbuf = kmem_cache_alloc(nilfs_segbuf_cachep, GFP_NOFS);
  39         if (unlikely(!segbuf))
  40                 return NULL;
  41
  42         segbuf->sb_super = sb;
  43         INIT_LIST_HEAD(&segbuf->sb_list);
  44         INIT_LIST_HEAD(&segbuf->sb_segsum_buffers);
  45         INIT_LIST_HEAD(&segbuf->sb_payload_buffers);
  46         segbuf->sb_super_root = NULL;
  47
  48         init_completion(&segbuf->sb_bio_event);
  49         atomic_set(&segbuf->sb_err, 0);
  50         segbuf->sb_nbio = 0;
  51
  52         return segbuf;
  53 }
  54
  55 void nilfs_segbuf_free(struct nilfs_segment_buffer *segbuf)
  56 {
  57         kmem_cache_free(nilfs_segbuf_cachep, segbuf);
  58 }
  59
  60 void nilfs_segbuf_map(struct nilfs_segment_buffer *segbuf, __u64 segnum,
  61                      unsigned long offset, struct the_nilfs *nilfs)
  62 {
  63         segbuf->sb_segnum = segnum;
  64         nilfs_get_segment_range(nilfs, segnum, &segbuf->sb_fseg_start,
  65                                 &segbuf->sb_fseg_end);
  66
  67         segbuf->sb_pseg_start = segbuf->sb_fseg_start + offset;
  68         segbuf->sb_rest_blocks =
  69                 segbuf->sb_fseg_end - segbuf->sb_pseg_start + 1;
  70 }
  71
  72 /**
  73  * nilfs_segbuf_map_cont - map a new log behind a given log
  74  * @segbuf: new segment buffer
  75  * @prev: segment buffer containing a log to be continued
  76  */
  77 void nilfs_segbuf_map_cont(struct nilfs_segment_buffer *segbuf,
  78                            struct nilfs_segment_buffer *prev)
  79 {
  80         segbuf->sb_segnum = prev->sb_segnum;
  81         segbuf->sb_fseg_start = prev->sb_fseg_start;
  82         segbuf->sb_fseg_end = prev->sb_fseg_end;
  83         segbuf->sb_pseg_start = prev->sb_pseg_start + prev->sb_sum.nblocks;
  84         segbuf->sb_rest_blocks =
  85                 segbuf->sb_fseg_end - segbuf->sb_pseg_start + 1;
  86 }
  87
  88 void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *segbuf,
  89                                   __u64 nextnum, struct the_nilfs *nilfs)
  90 {
  91         segbuf->sb_nextnum = nextnum;
  92         segbuf->sb_sum.next = nilfs_get_segment_start_blocknr(nilfs, nextnum);
  93 }
  94
  95 int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *segbuf)
  96 {
  97         struct buffer_head *bh;
  98
  99         bh = sb_getblk(segbuf->sb_super,
 100                        segbuf->sb_pseg_start + segbuf->sb_sum.nsumblk);
 101         if (unlikely(!bh))
 102                 return -ENOMEM;
 103
 104         nilfs_segbuf_add_segsum_buffer(segbuf, bh);
 105         return 0;
 106 }
 107
 108 int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *segbuf,
 109                                 struct buffer_head **bhp)
 110 {
 111         struct buffer_head *bh;
 112
 113         bh = sb_getblk(segbuf->sb_super,
 114                        segbuf->sb_pseg_start + segbuf->sb_sum.nblocks);
 115         if (unlikely(!bh))
 116                 return -ENOMEM;
 117
 118         nilfs_segbuf_add_payload_buffer(segbuf, bh);
 119         *bhp = bh;
 120         return 0;
 121 }
 122
 123 int nilfs_segbuf_reset(struct nilfs_segment_buffer *segbuf, unsigned int flags,
 124                        time64_t ctime, __u64 cno)
 125 {
 126         int err;
 127
 128         segbuf->sb_sum.nblocks = segbuf->sb_sum.nsumblk = 0;
 129         err = nilfs_segbuf_extend_segsum(segbuf);
 130         if (unlikely(err))
 131                 return err;
 132
 133         segbuf->sb_sum.flags = flags;
 134         segbuf->sb_sum.sumbytes = sizeof(struct nilfs_segment_summary);
 135         segbuf->sb_sum.nfinfo = segbuf->sb_sum.nfileblk = 0;
 136         segbuf->sb_sum.ctime = ctime;
 137         segbuf->sb_sum.cno = cno;
 138         return 0;
 139 }
 140
 141 /*
 142  * Setup segment summary
 143  */
 144 void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *segbuf)
 145 {
 146         struct nilfs_segment_summary *raw_sum;
 147         struct buffer_head *bh_sum;
 148
 149         bh_sum = list_entry(segbuf->sb_segsum_buffers.next,
 150                             struct buffer_head, b_assoc_buffers);
 151         raw_sum = (struct nilfs_segment_summary *)bh_sum->b_data;
 152
 153         raw_sum->ss_magic    = cpu_to_le32(NILFS_SEGSUM_MAGIC);
 154         raw_sum->ss_bytes    = cpu_to_le16(sizeof(*raw_sum));
 155         raw_sum->ss_flags    = cpu_to_le16(segbuf->sb_sum.flags);
 156         raw_sum->ss_seq      = cpu_to_le64(segbuf->sb_sum.seg_seq);
 157         raw_sum->ss_create   = cpu_to_le64(segbuf->sb_sum.ctime);
 158         raw_sum->ss_next     = cpu_to_le64(segbuf->sb_sum.next);
 159         raw_sum->ss_nblocks  = cpu_to_le32(segbuf->sb_sum.nblocks);
 160         raw_sum->ss_nfinfo   = cpu_to_le32(segbuf->sb_sum.nfinfo);
 161         raw_sum->ss_sumbytes = cpu_to_le32(segbuf->sb_sum.sumbytes);
 162         raw_sum->ss_pad      = 0;
 163         raw_sum->ss_cno      = cpu_to_le64(segbuf->sb_sum.cno);
 164 }
 165
 166 /*
 167  * CRC calculation routines
 168  */
 169 static void
 170 nilfs_segbuf_fill_in_segsum_crc(struct nilfs_segment_buffer *segbuf, u32 seed)
 171 {
 172         struct buffer_head *bh;
 173         struct nilfs_segment_summary *raw_sum;
 174         unsigned long size, bytes = segbuf->sb_sum.sumbytes;
 175         u32 crc;
 176
 177         bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
 178                         b_assoc_buffers);
 179
 180         raw_sum = (struct nilfs_segment_summary *)bh->b_data;
 181         size = min_t(unsigned long, bytes, bh->b_size);
 182         crc = crc32_le(seed,
 183                        (unsigned char *)raw_sum +
 184                        sizeof(raw_sum->ss_datasum) + sizeof(raw_sum->ss_sumsum),
 185                        size - (sizeof(raw_sum->ss_datasum) +
 186                                sizeof(raw_sum->ss_sumsum)));
 187
 188         list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
 189                                      b_assoc_buffers) {
 190                 bytes -= size;
 191                 size = min_t(unsigned long, bytes, bh->b_size);
 192                 crc = crc32_le(crc, bh->b_data, size);
 193         }
 194         raw_sum->ss_sumsum = cpu_to_le32(crc);
 195 }
 196
 197 static void nilfs_segbuf_fill_in_data_crc(struct nilfs_segment_buffer *segbuf,
 198                                           u32 seed)
 199 {
 200         struct buffer_head *bh;
 201         struct nilfs_segment_summary *raw_sum;
 202         void *kaddr;
 203         u32 crc;
 204
 205         bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
 206                         b_assoc_buffers);
 207         raw_sum = (struct nilfs_segment_summary *)bh->b_data;
 208         crc = crc32_le(seed,
 209                        (unsigned char *)raw_sum + sizeof(raw_sum->ss_datasum),
 210                        bh->b_size - sizeof(raw_sum->ss_datasum));
 211
 212         list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
 213                                      b_assoc_buffers) {
 214                 crc = crc32_le(crc, bh->b_data, bh->b_size);
 215         }
 216         list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
 217                 kaddr = kmap_atomic(bh->b_page);
 218                 crc = crc32_le(crc, kaddr + bh_offset(bh), bh->b_size);
 219                 kunmap_atomic(kaddr);
 220         }
 221         raw_sum->ss_datasum = cpu_to_le32(crc);
 222 }
 223
 224 static void
 225 nilfs_segbuf_fill_in_super_root_crc(struct nilfs_segment_buffer *segbuf,
 226                                     u32 seed)
 227 {
 228         struct nilfs_super_root *raw_sr;
 229         struct the_nilfs *nilfs = segbuf->sb_super->s_fs_info;
 230         unsigned int srsize;
 231         u32 crc;
 232
 233         raw_sr = (struct nilfs_super_root *)segbuf->sb_super_root->b_data;
 234         srsize = NILFS_SR_BYTES(nilfs->ns_inode_size);
 235         crc = crc32_le(seed,
 236                        (unsigned char *)raw_sr + sizeof(raw_sr->sr_sum),
 237                        srsize - sizeof(raw_sr->sr_sum));
 238         raw_sr->sr_sum = cpu_to_le32(crc);
 239 }
 240
 241 static void nilfs_release_buffers(struct list_head *list)
 242 {
 243         struct buffer_head *bh, *n;
 244
 245         list_for_each_entry_safe(bh, n, list, b_assoc_buffers) {
 246                 list_del_init(&bh->b_assoc_buffers);
 247                 brelse(bh);
 248         }
 249 }
 250
 251 static void nilfs_segbuf_clear(struct nilfs_segment_buffer *segbuf)
 252 {
 253         nilfs_release_buffers(&segbuf->sb_segsum_buffers);
 254         nilfs_release_buffers(&segbuf->sb_payload_buffers);
 255         segbuf->sb_super_root = NULL;
 256 }
 257
 258 /*
 259  * Iterators for segment buffers
 260  */
 261 void nilfs_clear_logs(struct list_head *logs)
 262 {
 263         struct nilfs_segment_buffer *segbuf;
 264
 265         list_for_each_entry(segbuf, logs, sb_list)
 266                 nilfs_segbuf_clear(segbuf);
 267 }
 268
 269 void nilfs_truncate_logs(struct list_head *logs,
 270                          struct nilfs_segment_buffer *last)
 271 {
 272         struct nilfs_segment_buffer *n, *segbuf;
 273
 274         segbuf = list_prepare_entry(last, logs, sb_list);
 275         list_for_each_entry_safe_continue(segbuf, n, logs, sb_list) {
 276                 list_del_init(&segbuf->sb_list);
 277                 nilfs_segbuf_clear(segbuf);
 278                 nilfs_segbuf_free(segbuf);
 279         }
 280 }
 281
 282 int nilfs_write_logs(struct list_head *logs, struct the_nilfs *nilfs)
 283 {
 284         struct nilfs_segment_buffer *segbuf;
 285         int ret = 0;
 286
 287         list_for_each_entry(segbuf, logs, sb_list) {
 288                 ret = nilfs_segbuf_write(segbuf, nilfs);
 289                 if (ret)
 290                         break;
 291         }
 292         return ret;
 293 }
 294
 295 int nilfs_wait_on_logs(struct list_head *logs)
 296 {
 297         struct nilfs_segment_buffer *segbuf;
 298         int err, ret = 0;
 299
 300         list_for_each_entry(segbuf, logs, sb_list) {
 301                 err = nilfs_segbuf_wait(segbuf);
 302                 if (err && !ret)
 303                         ret = err;
 304         }
 305         return ret;
 306 }
 307
 308 /**
 309  * nilfs_add_checksums_on_logs - add checksums on the logs
 310  * @logs: list of segment buffers storing target logs
 311  * @seed: checksum seed value
 312  */
 313 void nilfs_add_checksums_on_logs(struct list_head *logs, u32 seed)
 314 {
 315         struct nilfs_segment_buffer *segbuf;
 316
 317         list_for_each_entry(segbuf, logs, sb_list) {
 318                 if (segbuf->sb_super_root)
 319                         nilfs_segbuf_fill_in_super_root_crc(segbuf, seed);
 320                 nilfs_segbuf_fill_in_segsum_crc(segbuf, seed);
 321                 nilfs_segbuf_fill_in_data_crc(segbuf, seed);
 322         }
 323 }
 324
 325 /*
 326  * BIO operations
 327  */
 328 static void nilfs_end_bio_write(struct bio *bio)
 329 {
 330         struct nilfs_segment_buffer *segbuf = bio->bi_private;
 331
 332         if (bio->bi_status)
 333                 atomic_inc(&segbuf->sb_err);
 334
 335         bio_put(bio);
 336         complete(&segbuf->sb_bio_event);
 337 }
 338
 339 static int nilfs_segbuf_submit_bio(struct nilfs_segment_buffer *segbuf,
 340                                    struct nilfs_write_info *wi, int mode,
 341                                    int mode_flags)
 342 {
 343         struct bio *bio = wi->bio;
 344         int err;
 345
 346         if (segbuf->sb_nbio > 0 &&
 347             bdi_write_congested(segbuf->sb_super->s_bdi)) {
 348                 wait_for_completion(&segbuf->sb_bio_event);
 349                 segbuf->sb_nbio--;
 350                 if (unlikely(atomic_read(&segbuf->sb_err))) {
 351                         bio_put(bio);
 352                         err = -EIO;
 353                         goto failed;
 354                 }
 355         }
 356
 357         bio->bi_end_io = nilfs_end_bio_write;
 358         bio->bi_private = segbuf;
 359         bio_set_op_attrs(bio, mode, mode_flags);
 360         submit_bio(bio);
 361         segbuf->sb_nbio++;
 362
 363         wi->bio = NULL;
 364         wi->rest_blocks -= wi->end - wi->start;
 365         wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
 366         wi->start = wi->end;
 367         return 0;
 368
 369  failed:
 370         wi->bio = NULL;
 371         return err;
 372 }
 373
 374 /**
 375  * nilfs_alloc_seg_bio - allocate a new bio for writing log
 376  * @nilfs: nilfs object
 377  * @start: start block number of the bio
 378  * @nr_vecs: request size of page vector.
 379  *
 380  * Return Value: On success, pointer to the struct bio is returned.
 381  * On error, NULL is returned.
 382  */
 383 static struct bio *nilfs_alloc_seg_bio(struct the_nilfs *nilfs, sector_t start,
 384                                        int nr_vecs)
 385 {
 386         struct bio *bio;
 387
 388         bio = bio_alloc(GFP_NOIO, nr_vecs);
 389         if (bio == NULL) {
 390                 while (!bio && (nr_vecs >>= 1))
 391                         bio = bio_alloc(GFP_NOIO, nr_vecs);
 392         }
 393         if (likely(bio)) {
 394                 bio_set_dev(bio, nilfs->ns_bdev);
 395                 bio->bi_iter.bi_sector =
 396                         start << (nilfs->ns_blocksize_bits - 9);
 397         }
 398         return bio;
 399 }
 400
 401 static void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *segbuf,
 402                                        struct nilfs_write_info *wi)
 403 {
 404         wi->bio = NULL;
 405         wi->rest_blocks = segbuf->sb_sum.nblocks;
 406         wi->max_pages = BIO_MAX_PAGES;
 407         wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
 408         wi->start = wi->end = 0;
 409         wi->blocknr = segbuf->sb_pseg_start;
 410 }
 411
 412 static int nilfs_segbuf_submit_bh(struct nilfs_segment_buffer *segbuf,
 413                                   struct nilfs_write_info *wi,
 414                                   struct buffer_head *bh, int mode)
 415 {
 416         int len, err;
 417
 418         BUG_ON(wi->nr_vecs <= 0);
 419  repeat:
 420         if (!wi->bio) {
 421                 wi->bio = nilfs_alloc_seg_bio(wi->nilfs, wi->blocknr + wi->end,
 422                                               wi->nr_vecs);
 423                 if (unlikely(!wi->bio))
 424                         return -ENOMEM;
 425         }
 426
 427         len = bio_add_page(wi->bio, bh->b_page, bh->b_size, bh_offset(bh));
 428         if (len == bh->b_size) {
 429                 wi->end++;
 430                 return 0;
 431         }
 432         /* bio is FULL */
 433         err = nilfs_segbuf_submit_bio(segbuf, wi, mode, 0);
 434         /* never submit current bh */
 435         if (likely(!err))
 436                 goto repeat;
 437         return err;
 438 }
 439
 440 /**
 441  * nilfs_segbuf_write - submit write requests of a log
 442  * @segbuf: buffer storing a log to be written
 443  * @nilfs: nilfs object
 444  *
 445  * Return Value: On Success, 0 is returned. On Error, one of the following
 446  * negative error code is returned.
 447  *
 448  * %-EIO - I/O error
 449  *
 450  * %-ENOMEM - Insufficient memory available.
 451  */
 452 static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
 453                               struct the_nilfs *nilfs)
 454 {
 455         struct nilfs_write_info wi;
 456         struct buffer_head *bh;
 457         int res = 0;
 458
 459         wi.nilfs = nilfs;
 460         nilfs_segbuf_prepare_write(segbuf, &wi);
 461
 462         list_for_each_entry(bh, &segbuf->sb_segsum_buffers, b_assoc_buffers) {
 463                 res = nilfs_segbuf_submit_bh(segbuf, &wi, bh, REQ_OP_WRITE);
 464                 if (unlikely(res))
 465                         goto failed_bio;
 466         }
 467
 468         list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
 469                 res = nilfs_segbuf_submit_bh(segbuf, &wi, bh, REQ_OP_WRITE);
 470                 if (unlikely(res))
 471                         goto failed_bio;
 472         }
 473
 474         if (wi.bio) {
 475                 /*
 476                  * Last BIO is always sent through the following
 477                  * submission.
 478                  */
 479                 res = nilfs_segbuf_submit_bio(segbuf, &wi, REQ_OP_WRITE,
 480                                               REQ_SYNC);
 481         }
 482
 483  failed_bio:
 484         return res;
 485 }
 486
 487 /**
 488  * nilfs_segbuf_wait - wait for completion of requested BIOs
 489  * @segbuf: segment buffer
 490  *
 491  * Return Value: On Success, 0 is returned. On Error, one of the following
 492  * negative error code is returned.
 493  *
 494  * %-EIO - I/O error
 495  */
 496 static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf)
 497 {
 498         int err = 0;
 499
 500         if (!segbuf->sb_nbio)
 501                 return 0;
 502
 503         do {
 504                 wait_for_completion(&segbuf->sb_bio_event);
 505         } while (--segbuf->sb_nbio > 0);
 506
 507         if (unlikely(atomic_read(&segbuf->sb_err) > 0)) {
 508                 nilfs_msg(segbuf->sb_super, KERN_ERR,
 509                           "I/O error writing log (start-blocknr=%llu, block-count=%lu) in segment %llu",
 510                           (unsigned long long)segbuf->sb_pseg_start,
 511                           segbuf->sb_sum.nblocks,
 512                           (unsigned long long)segbuf->sb_segnum);
 513                 err = -EIO;
 514         }
 515         return err;
 516 }