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         lock_buffer(bh);
 105         if (!buffer_uptodate(bh)) {
 106                 memset(bh->b_data, 0, bh->b_size);
 107                 set_buffer_uptodate(bh);
 108         }
 109         unlock_buffer(bh);
 110         nilfs_segbuf_add_segsum_buffer(segbuf, bh);
 111         return 0;
 112 }
 113
 114 int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *segbuf,
 115                                 struct buffer_head **bhp)
 116 {
 117         struct buffer_head *bh;
 118
 119         bh = sb_getblk(segbuf->sb_super,
 120                        segbuf->sb_pseg_start + segbuf->sb_sum.nblocks);
 121         if (unlikely(!bh))
 122                 return -ENOMEM;
 123
 124         nilfs_segbuf_add_payload_buffer(segbuf, bh);
 125         *bhp = bh;
 126         return 0;
 127 }
 128
 129 int nilfs_segbuf_reset(struct nilfs_segment_buffer *segbuf, unsigned int flags,
 130                        time64_t ctime, __u64 cno)
 131 {
 132         int err;
 133
 134         segbuf->sb_sum.nblocks = segbuf->sb_sum.nsumblk = 0;
 135         err = nilfs_segbuf_extend_segsum(segbuf);
 136         if (unlikely(err))
 137                 return err;
 138
 139         segbuf->sb_sum.flags = flags;
 140         segbuf->sb_sum.sumbytes = sizeof(struct nilfs_segment_summary);
 141         segbuf->sb_sum.nfinfo = segbuf->sb_sum.nfileblk = 0;
 142         segbuf->sb_sum.ctime = ctime;
 143         segbuf->sb_sum.cno = cno;
 144         return 0;
 145 }
 146
 147 /*
 148  * Setup segment summary
 149  */
 150 void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *segbuf)
 151 {
 152         struct nilfs_segment_summary *raw_sum;
 153         struct buffer_head *bh_sum;
 154
 155         bh_sum = list_entry(segbuf->sb_segsum_buffers.next,
 156                             struct buffer_head, b_assoc_buffers);
 157         raw_sum = (struct nilfs_segment_summary *)bh_sum->b_data;
 158
 159         raw_sum->ss_magic    = cpu_to_le32(NILFS_SEGSUM_MAGIC);
 160         raw_sum->ss_bytes    = cpu_to_le16(sizeof(*raw_sum));
 161         raw_sum->ss_flags    = cpu_to_le16(segbuf->sb_sum.flags);
 162         raw_sum->ss_seq      = cpu_to_le64(segbuf->sb_sum.seg_seq);
 163         raw_sum->ss_create   = cpu_to_le64(segbuf->sb_sum.ctime);
 164         raw_sum->ss_next     = cpu_to_le64(segbuf->sb_sum.next);
 165         raw_sum->ss_nblocks  = cpu_to_le32(segbuf->sb_sum.nblocks);
 166         raw_sum->ss_nfinfo   = cpu_to_le32(segbuf->sb_sum.nfinfo);
 167         raw_sum->ss_sumbytes = cpu_to_le32(segbuf->sb_sum.sumbytes);
 168         raw_sum->ss_pad      = 0;
 169         raw_sum->ss_cno      = cpu_to_le64(segbuf->sb_sum.cno);
 170 }
 171
 172 /*
 173  * CRC calculation routines
 174  */
 175 static void
 176 nilfs_segbuf_fill_in_segsum_crc(struct nilfs_segment_buffer *segbuf, u32 seed)
 177 {
 178         struct buffer_head *bh;
 179         struct nilfs_segment_summary *raw_sum;
 180         unsigned long size, bytes = segbuf->sb_sum.sumbytes;
 181         u32 crc;
 182
 183         bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
 184                         b_assoc_buffers);
 185
 186         raw_sum = (struct nilfs_segment_summary *)bh->b_data;
 187         size = min_t(unsigned long, bytes, bh->b_size);
 188         crc = crc32_le(seed,
 189                        (unsigned char *)raw_sum +
 190                        sizeof(raw_sum->ss_datasum) + sizeof(raw_sum->ss_sumsum),
 191                        size - (sizeof(raw_sum->ss_datasum) +
 192                                sizeof(raw_sum->ss_sumsum)));
 193
 194         list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
 195                                      b_assoc_buffers) {
 196                 bytes -= size;
 197                 size = min_t(unsigned long, bytes, bh->b_size);
 198                 crc = crc32_le(crc, bh->b_data, size);
 199         }
 200         raw_sum->ss_sumsum = cpu_to_le32(crc);
 201 }
 202
 203 static void nilfs_segbuf_fill_in_data_crc(struct nilfs_segment_buffer *segbuf,
 204                                           u32 seed)
 205 {
 206         struct buffer_head *bh;
 207         struct nilfs_segment_summary *raw_sum;
 208         void *kaddr;
 209         u32 crc;
 210
 211         bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
 212                         b_assoc_buffers);
 213         raw_sum = (struct nilfs_segment_summary *)bh->b_data;
 214         crc = crc32_le(seed,
 215                        (unsigned char *)raw_sum + sizeof(raw_sum->ss_datasum),
 216                        bh->b_size - sizeof(raw_sum->ss_datasum));
 217
 218         list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
 219                                      b_assoc_buffers) {
 220                 crc = crc32_le(crc, bh->b_data, bh->b_size);
 221         }
 222         list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
 223                 kaddr = kmap_atomic(bh->b_page);
 224                 crc = crc32_le(crc, kaddr + bh_offset(bh), bh->b_size);
 225                 kunmap_atomic(kaddr);
 226         }
 227         raw_sum->ss_datasum = cpu_to_le32(crc);
 228 }
 229
 230 static void
 231 nilfs_segbuf_fill_in_super_root_crc(struct nilfs_segment_buffer *segbuf,
 232                                     u32 seed)
 233 {
 234         struct nilfs_super_root *raw_sr;
 235         struct the_nilfs *nilfs = segbuf->sb_super->s_fs_info;
 236         unsigned int srsize;
 237         u32 crc;
 238
 239         raw_sr = (struct nilfs_super_root *)segbuf->sb_super_root->b_data;
 240         srsize = NILFS_SR_BYTES(nilfs->ns_inode_size);
 241         crc = crc32_le(seed,
 242                        (unsigned char *)raw_sr + sizeof(raw_sr->sr_sum),
 243                        srsize - sizeof(raw_sr->sr_sum));
 244         raw_sr->sr_sum = cpu_to_le32(crc);
 245 }
 246
 247 static void nilfs_release_buffers(struct list_head *list)
 248 {
 249         struct buffer_head *bh, *n;
 250
 251         list_for_each_entry_safe(bh, n, list, b_assoc_buffers) {
 252                 list_del_init(&bh->b_assoc_buffers);
 253                 brelse(bh);
 254         }
 255 }
 256
 257 static void nilfs_segbuf_clear(struct nilfs_segment_buffer *segbuf)
 258 {
 259         nilfs_release_buffers(&segbuf->sb_segsum_buffers);
 260         nilfs_release_buffers(&segbuf->sb_payload_buffers);
 261         segbuf->sb_super_root = NULL;
 262 }
 263
 264 /*
 265  * Iterators for segment buffers
 266  */
 267 void nilfs_clear_logs(struct list_head *logs)
 268 {
 269         struct nilfs_segment_buffer *segbuf;
 270
 271         list_for_each_entry(segbuf, logs, sb_list)
 272                 nilfs_segbuf_clear(segbuf);
 273 }
 274
 275 void nilfs_truncate_logs(struct list_head *logs,
 276                          struct nilfs_segment_buffer *last)
 277 {
 278         struct nilfs_segment_buffer *n, *segbuf;
 279
 280         segbuf = list_prepare_entry(last, logs, sb_list);
 281         list_for_each_entry_safe_continue(segbuf, n, logs, sb_list) {
 282                 list_del_init(&segbuf->sb_list);
 283                 nilfs_segbuf_clear(segbuf);
 284                 nilfs_segbuf_free(segbuf);
 285         }
 286 }
 287
 288 int nilfs_write_logs(struct list_head *logs, struct the_nilfs *nilfs)
 289 {
 290         struct nilfs_segment_buffer *segbuf;
 291         int ret = 0;
 292
 293         list_for_each_entry(segbuf, logs, sb_list) {
 294                 ret = nilfs_segbuf_write(segbuf, nilfs);
 295                 if (ret)
 296                         break;
 297         }
 298         return ret;
 299 }
 300
 301 int nilfs_wait_on_logs(struct list_head *logs)
 302 {
 303         struct nilfs_segment_buffer *segbuf;
 304         int err, ret = 0;
 305
 306         list_for_each_entry(segbuf, logs, sb_list) {
 307                 err = nilfs_segbuf_wait(segbuf);
 308                 if (err && !ret)
 309                         ret = err;
 310         }
 311         return ret;
 312 }
 313
 314 /**
 315  * nilfs_add_checksums_on_logs - add checksums on the logs
 316  * @logs: list of segment buffers storing target logs
 317  * @seed: checksum seed value
 318  */
 319 void nilfs_add_checksums_on_logs(struct list_head *logs, u32 seed)
 320 {
 321         struct nilfs_segment_buffer *segbuf;
 322
 323         list_for_each_entry(segbuf, logs, sb_list) {
 324                 if (segbuf->sb_super_root)
 325                         nilfs_segbuf_fill_in_super_root_crc(segbuf, seed);
 326                 nilfs_segbuf_fill_in_segsum_crc(segbuf, seed);
 327                 nilfs_segbuf_fill_in_data_crc(segbuf, seed);
 328         }
 329 }
 330
 331 /*
 332  * BIO operations
 333  */
 334 static void nilfs_end_bio_write(struct bio *bio)
 335 {
 336         struct nilfs_segment_buffer *segbuf = bio->bi_private;
 337
 338         if (bio->bi_status)
 339                 atomic_inc(&segbuf->sb_err);
 340
 341         bio_put(bio);
 342         complete(&segbuf->sb_bio_event);
 343 }
 344
 345 static int nilfs_segbuf_submit_bio(struct nilfs_segment_buffer *segbuf,
 346                                    struct nilfs_write_info *wi, int mode,
 347                                    int mode_flags)
 348 {
 349         struct bio *bio = wi->bio;
 350         int err;
 351
 352         if (segbuf->sb_nbio > 0 &&
 353             bdi_write_congested(segbuf->sb_super->s_bdi)) {
 354                 wait_for_completion(&segbuf->sb_bio_event);
 355                 segbuf->sb_nbio--;
 356                 if (unlikely(atomic_read(&segbuf->sb_err))) {
 357                         bio_put(bio);
 358                         err = -EIO;
 359                         goto failed;
 360                 }
 361         }
 362
 363         bio->bi_end_io = nilfs_end_bio_write;
 364         bio->bi_private = segbuf;
 365         bio_set_op_attrs(bio, mode, mode_flags);
 366         submit_bio(bio);
 367         segbuf->sb_nbio++;
 368
 369         wi->bio = NULL;
 370         wi->rest_blocks -= wi->end - wi->start;
 371         wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
 372         wi->start = wi->end;
 373         return 0;
 374
 375  failed:
 376         wi->bio = NULL;
 377         return err;
 378 }
 379
 380 /**
 381  * nilfs_alloc_seg_bio - allocate a new bio for writing log
 382  * @nilfs: nilfs object
 383  * @start: start block number of the bio
 384  * @nr_vecs: request size of page vector.
 385  *
 386  * Return Value: On success, pointer to the struct bio is returned.
 387  * On error, NULL is returned.
 388  */
 389 static struct bio *nilfs_alloc_seg_bio(struct the_nilfs *nilfs, sector_t start,
 390                                        int nr_vecs)
 391 {
 392         struct bio *bio;
 393
 394         bio = bio_alloc(GFP_NOIO, nr_vecs);
 395         if (bio == NULL) {
 396                 while (!bio && (nr_vecs >>= 1))
 397                         bio = bio_alloc(GFP_NOIO, nr_vecs);
 398         }
 399         if (likely(bio)) {
 400                 bio_set_dev(bio, nilfs->ns_bdev);
 401                 bio->bi_iter.bi_sector =
 402                         start << (nilfs->ns_blocksize_bits - 9);
 403         }
 404         return bio;
 405 }
 406
 407 static void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *segbuf,
 408                                        struct nilfs_write_info *wi)
 409 {
 410         wi->bio = NULL;
 411         wi->rest_blocks = segbuf->sb_sum.nblocks;
 412         wi->max_pages = BIO_MAX_PAGES;
 413         wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
 414         wi->start = wi->end = 0;
 415         wi->blocknr = segbuf->sb_pseg_start;
 416 }
 417
 418 static int nilfs_segbuf_submit_bh(struct nilfs_segment_buffer *segbuf,
 419                                   struct nilfs_write_info *wi,
 420                                   struct buffer_head *bh, int mode)
 421 {
 422         int len, err;
 423
 424         BUG_ON(wi->nr_vecs <= 0);
 425  repeat:
 426         if (!wi->bio) {
 427                 wi->bio = nilfs_alloc_seg_bio(wi->nilfs, wi->blocknr + wi->end,
 428                                               wi->nr_vecs);
 429                 if (unlikely(!wi->bio))
 430                         return -ENOMEM;
 431         }
 432
 433         len = bio_add_page(wi->bio, bh->b_page, bh->b_size, bh_offset(bh));
 434         if (len == bh->b_size) {
 435                 wi->end++;
 436                 return 0;
 437         }
 438         /* bio is FULL */
 439         err = nilfs_segbuf_submit_bio(segbuf, wi, mode, 0);
 440         /* never submit current bh */
 441         if (likely(!err))
 442                 goto repeat;
 443         return err;
 444 }
 445
 446 /**
 447  * nilfs_segbuf_write - submit write requests of a log
 448  * @segbuf: buffer storing a log to be written
 449  * @nilfs: nilfs object
 450  *
 451  * Return Value: On Success, 0 is returned. On Error, one of the following
 452  * negative error code is returned.
 453  *
 454  * %-EIO - I/O error
 455  *
 456  * %-ENOMEM - Insufficient memory available.
 457  */
 458 static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
 459                               struct the_nilfs *nilfs)
 460 {
 461         struct nilfs_write_info wi;
 462         struct buffer_head *bh;
 463         int res = 0;
 464
 465         wi.nilfs = nilfs;
 466         nilfs_segbuf_prepare_write(segbuf, &wi);
 467
 468         list_for_each_entry(bh, &segbuf->sb_segsum_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         list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
 475                 res = nilfs_segbuf_submit_bh(segbuf, &wi, bh, REQ_OP_WRITE);
 476                 if (unlikely(res))
 477                         goto failed_bio;
 478         }
 479
 480         if (wi.bio) {
 481                 /*
 482                  * Last BIO is always sent through the following
 483                  * submission.
 484                  */
 485                 res = nilfs_segbuf_submit_bio(segbuf, &wi, REQ_OP_WRITE,
 486                                               REQ_SYNC);
 487         }
 488
 489  failed_bio:
 490         return res;
 491 }
 492
 493 /**
 494  * nilfs_segbuf_wait - wait for completion of requested BIOs
 495  * @segbuf: segment buffer
 496  *
 497  * Return Value: On Success, 0 is returned. On Error, one of the following
 498  * negative error code is returned.
 499  *
 500  * %-EIO - I/O error
 501  */
 502 static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf)
 503 {
 504         int err = 0;
 505
 506         if (!segbuf->sb_nbio)
 507                 return 0;
 508
 509         do {
 510                 wait_for_completion(&segbuf->sb_bio_event);
 511         } while (--segbuf->sb_nbio > 0);
 512
 513         if (unlikely(atomic_read(&segbuf->sb_err) > 0)) {
 514                 nilfs_msg(segbuf->sb_super, KERN_ERR,
 515                           "I/O error writing log (start-blocknr=%llu, block-count=%lu) in segment %llu",
 516                           (unsigned long long)segbuf->sb_pseg_start,
 517                           segbuf->sb_sum.nblocks,
 518                           (unsigned long long)segbuf->sb_segnum);
 519                 err = -EIO;
 520         }
 521         return err;
 522 }