fs/nilfs2/segbuf.c

   1 /*
   2  * segbuf.c - NILFS segment buffer
   3  *
   4  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * Written by Ryusuke Konishi.
  17  *
  18  */
  19
  20 #include <linux/buffer_head.h>
  21 #include <linux/writeback.h>
  22 #include <linux/crc32.h>
  23 #include <linux/backing-dev.h>
  24 #include <linux/slab.h>
  25 #include "page.h"
  26 #include "segbuf.h"
  27
  28
  29 struct nilfs_write_info {
  30         struct the_nilfs       *nilfs;
  31         struct bio             *bio;
  32         int                     start, end; /* The region to be submitted */
  33         int                     rest_blocks;
  34         int                     max_pages;
  35         int                     nr_vecs;
  36         sector_t                blocknr;
  37 };
  38
  39 static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
  40                               struct the_nilfs *nilfs);
  41 static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf);
  42
  43 struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *sb)
  44 {
  45         struct nilfs_segment_buffer *segbuf;
  46
  47         segbuf = kmem_cache_alloc(nilfs_segbuf_cachep, GFP_NOFS);
  48         if (unlikely(!segbuf))
  49                 return NULL;
  50
  51         segbuf->sb_super = sb;
  52         INIT_LIST_HEAD(&segbuf->sb_list);
  53         INIT_LIST_HEAD(&segbuf->sb_segsum_buffers);
  54         INIT_LIST_HEAD(&segbuf->sb_payload_buffers);
  55         segbuf->sb_super_root = NULL;
  56
  57         init_completion(&segbuf->sb_bio_event);
  58         atomic_set(&segbuf->sb_err, 0);
  59         segbuf->sb_nbio = 0;
  60
  61         return segbuf;
  62 }
  63
  64 void nilfs_segbuf_free(struct nilfs_segment_buffer *segbuf)
  65 {
  66         kmem_cache_free(nilfs_segbuf_cachep, segbuf);
  67 }
  68
  69 void nilfs_segbuf_map(struct nilfs_segment_buffer *segbuf, __u64 segnum,
  70                      unsigned long offset, struct the_nilfs *nilfs)
  71 {
  72         segbuf->sb_segnum = segnum;
  73         nilfs_get_segment_range(nilfs, segnum, &segbuf->sb_fseg_start,
  74                                 &segbuf->sb_fseg_end);
  75
  76         segbuf->sb_pseg_start = segbuf->sb_fseg_start + offset;
  77         segbuf->sb_rest_blocks =
  78                 segbuf->sb_fseg_end - segbuf->sb_pseg_start + 1;
  79 }
  80
  81 /**
  82  * nilfs_segbuf_map_cont - map a new log behind a given log
  83  * @segbuf: new segment buffer
  84  * @prev: segment buffer containing a log to be continued
  85  */
  86 void nilfs_segbuf_map_cont(struct nilfs_segment_buffer *segbuf,
  87                            struct nilfs_segment_buffer *prev)
  88 {
  89         segbuf->sb_segnum = prev->sb_segnum;
  90         segbuf->sb_fseg_start = prev->sb_fseg_start;
  91         segbuf->sb_fseg_end = prev->sb_fseg_end;
  92         segbuf->sb_pseg_start = prev->sb_pseg_start + prev->sb_sum.nblocks;
  93         segbuf->sb_rest_blocks =
  94                 segbuf->sb_fseg_end - segbuf->sb_pseg_start + 1;
  95 }
  96
  97 void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *segbuf,
  98                                   __u64 nextnum, struct the_nilfs *nilfs)
  99 {
 100         segbuf->sb_nextnum = nextnum;
 101         segbuf->sb_sum.next = nilfs_get_segment_start_blocknr(nilfs, nextnum);
 102 }
 103
 104 int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *segbuf)
 105 {
 106         struct buffer_head *bh;
 107
 108         bh = sb_getblk(segbuf->sb_super,
 109                        segbuf->sb_pseg_start + segbuf->sb_sum.nsumblk);
 110         if (unlikely(!bh))
 111                 return -ENOMEM;
 112
 113         lock_buffer(bh);
 114         if (!buffer_uptodate(bh)) {
 115                 memset(bh->b_data, 0, bh->b_size);
 116                 set_buffer_uptodate(bh);
 117         }
 118         unlock_buffer(bh);
 119         nilfs_segbuf_add_segsum_buffer(segbuf, bh);
 120         return 0;
 121 }
 122
 123 int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *segbuf,
 124                                 struct buffer_head **bhp)
 125 {
 126         struct buffer_head *bh;
 127
 128         bh = sb_getblk(segbuf->sb_super,
 129                        segbuf->sb_pseg_start + segbuf->sb_sum.nblocks);
 130         if (unlikely(!bh))
 131                 return -ENOMEM;
 132
 133         nilfs_segbuf_add_payload_buffer(segbuf, bh);
 134         *bhp = bh;
 135         return 0;
 136 }
 137
 138 int nilfs_segbuf_reset(struct nilfs_segment_buffer *segbuf, unsigned int flags,
 139                        time_t ctime, __u64 cno)
 140 {
 141         int err;
 142
 143         segbuf->sb_sum.nblocks = segbuf->sb_sum.nsumblk = 0;
 144         err = nilfs_segbuf_extend_segsum(segbuf);
 145         if (unlikely(err))
 146                 return err;
 147
 148         segbuf->sb_sum.flags = flags;
 149         segbuf->sb_sum.sumbytes = sizeof(struct nilfs_segment_summary);
 150         segbuf->sb_sum.nfinfo = segbuf->sb_sum.nfileblk = 0;
 151         segbuf->sb_sum.ctime = ctime;
 152         segbuf->sb_sum.cno = cno;
 153         return 0;
 154 }
 155
 156 /*
 157  * Setup segment summary
 158  */
 159 void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *segbuf)
 160 {
 161         struct nilfs_segment_summary *raw_sum;
 162         struct buffer_head *bh_sum;
 163
 164         bh_sum = list_entry(segbuf->sb_segsum_buffers.next,
 165                             struct buffer_head, b_assoc_buffers);
 166         raw_sum = (struct nilfs_segment_summary *)bh_sum->b_data;
 167
 168         raw_sum->ss_magic    = cpu_to_le32(NILFS_SEGSUM_MAGIC);
 169         raw_sum->ss_bytes    = cpu_to_le16(sizeof(*raw_sum));
 170         raw_sum->ss_flags    = cpu_to_le16(segbuf->sb_sum.flags);
 171         raw_sum->ss_seq      = cpu_to_le64(segbuf->sb_sum.seg_seq);
 172         raw_sum->ss_create   = cpu_to_le64(segbuf->sb_sum.ctime);
 173         raw_sum->ss_next     = cpu_to_le64(segbuf->sb_sum.next);
 174         raw_sum->ss_nblocks  = cpu_to_le32(segbuf->sb_sum.nblocks);
 175         raw_sum->ss_nfinfo   = cpu_to_le32(segbuf->sb_sum.nfinfo);
 176         raw_sum->ss_sumbytes = cpu_to_le32(segbuf->sb_sum.sumbytes);
 177         raw_sum->ss_pad      = 0;
 178         raw_sum->ss_cno      = cpu_to_le64(segbuf->sb_sum.cno);
 179 }
 180
 181 /*
 182  * CRC calculation routines
 183  */
 184 static void
 185 nilfs_segbuf_fill_in_segsum_crc(struct nilfs_segment_buffer *segbuf, u32 seed)
 186 {
 187         struct buffer_head *bh;
 188         struct nilfs_segment_summary *raw_sum;
 189         unsigned long size, bytes = segbuf->sb_sum.sumbytes;
 190         u32 crc;
 191
 192         bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
 193                         b_assoc_buffers);
 194
 195         raw_sum = (struct nilfs_segment_summary *)bh->b_data;
 196         size = min_t(unsigned long, bytes, bh->b_size);
 197         crc = crc32_le(seed,
 198                        (unsigned char *)raw_sum +
 199                        sizeof(raw_sum->ss_datasum) + sizeof(raw_sum->ss_sumsum),
 200                        size - (sizeof(raw_sum->ss_datasum) +
 201                                sizeof(raw_sum->ss_sumsum)));
 202
 203         list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
 204                                      b_assoc_buffers) {
 205                 bytes -= size;
 206                 size = min_t(unsigned long, bytes, bh->b_size);
 207                 crc = crc32_le(crc, bh->b_data, size);
 208         }
 209         raw_sum->ss_sumsum = cpu_to_le32(crc);
 210 }
 211
 212 static void nilfs_segbuf_fill_in_data_crc(struct nilfs_segment_buffer *segbuf,
 213                                           u32 seed)
 214 {
 215         struct buffer_head *bh;
 216         struct nilfs_segment_summary *raw_sum;
 217         void *kaddr;
 218         u32 crc;
 219
 220         bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
 221                         b_assoc_buffers);
 222         raw_sum = (struct nilfs_segment_summary *)bh->b_data;
 223         crc = crc32_le(seed,
 224                        (unsigned char *)raw_sum + sizeof(raw_sum->ss_datasum),
 225                        bh->b_size - sizeof(raw_sum->ss_datasum));
 226
 227         list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
 228                                      b_assoc_buffers) {
 229                 crc = crc32_le(crc, bh->b_data, bh->b_size);
 230         }
 231         list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
 232                 kaddr = kmap_atomic(bh->b_page);
 233                 crc = crc32_le(crc, kaddr + bh_offset(bh), bh->b_size);
 234                 kunmap_atomic(kaddr);
 235         }
 236         raw_sum->ss_datasum = cpu_to_le32(crc);
 237 }
 238
 239 static void
 240 nilfs_segbuf_fill_in_super_root_crc(struct nilfs_segment_buffer *segbuf,
 241                                     u32 seed)
 242 {
 243         struct nilfs_super_root *raw_sr;
 244         struct the_nilfs *nilfs = segbuf->sb_super->s_fs_info;
 245         unsigned int srsize;
 246         u32 crc;
 247
 248         raw_sr = (struct nilfs_super_root *)segbuf->sb_super_root->b_data;
 249         srsize = NILFS_SR_BYTES(nilfs->ns_inode_size);
 250         crc = crc32_le(seed,
 251                        (unsigned char *)raw_sr + sizeof(raw_sr->sr_sum),
 252                        srsize - sizeof(raw_sr->sr_sum));
 253         raw_sr->sr_sum = cpu_to_le32(crc);
 254 }
 255
 256 static void nilfs_release_buffers(struct list_head *list)
 257 {
 258         struct buffer_head *bh, *n;
 259
 260         list_for_each_entry_safe(bh, n, list, b_assoc_buffers) {
 261                 list_del_init(&bh->b_assoc_buffers);
 262                 brelse(bh);
 263         }
 264 }
 265
 266 static void nilfs_segbuf_clear(struct nilfs_segment_buffer *segbuf)
 267 {
 268         nilfs_release_buffers(&segbuf->sb_segsum_buffers);
 269         nilfs_release_buffers(&segbuf->sb_payload_buffers);
 270         segbuf->sb_super_root = NULL;
 271 }
 272
 273 /*
 274  * Iterators for segment buffers
 275  */
 276 void nilfs_clear_logs(struct list_head *logs)
 277 {
 278         struct nilfs_segment_buffer *segbuf;
 279
 280         list_for_each_entry(segbuf, logs, sb_list)
 281                 nilfs_segbuf_clear(segbuf);
 282 }
 283
 284 void nilfs_truncate_logs(struct list_head *logs,
 285                          struct nilfs_segment_buffer *last)
 286 {
 287         struct nilfs_segment_buffer *n, *segbuf;
 288
 289         segbuf = list_prepare_entry(last, logs, sb_list);
 290         list_for_each_entry_safe_continue(segbuf, n, logs, sb_list) {
 291                 list_del_init(&segbuf->sb_list);
 292                 nilfs_segbuf_clear(segbuf);
 293                 nilfs_segbuf_free(segbuf);
 294         }
 295 }
 296
 297 int nilfs_write_logs(struct list_head *logs, struct the_nilfs *nilfs)
 298 {
 299         struct nilfs_segment_buffer *segbuf;
 300         int ret = 0;
 301
 302         list_for_each_entry(segbuf, logs, sb_list) {
 303                 ret = nilfs_segbuf_write(segbuf, nilfs);
 304                 if (ret)
 305                         break;
 306         }
 307         return ret;
 308 }
 309
 310 int nilfs_wait_on_logs(struct list_head *logs)
 311 {
 312         struct nilfs_segment_buffer *segbuf;
 313         int err, ret = 0;
 314
 315         list_for_each_entry(segbuf, logs, sb_list) {
 316                 err = nilfs_segbuf_wait(segbuf);
 317                 if (err && !ret)
 318                         ret = err;
 319         }
 320         return ret;
 321 }
 322
 323 /**
 324  * nilfs_add_checksums_on_logs - add checksums on the logs
 325  * @logs: list of segment buffers storing target logs
 326  * @seed: checksum seed value
 327  */
 328 void nilfs_add_checksums_on_logs(struct list_head *logs, u32 seed)
 329 {
 330         struct nilfs_segment_buffer *segbuf;
 331
 332         list_for_each_entry(segbuf, logs, sb_list) {
 333                 if (segbuf->sb_super_root)
 334                         nilfs_segbuf_fill_in_super_root_crc(segbuf, seed);
 335                 nilfs_segbuf_fill_in_segsum_crc(segbuf, seed);
 336                 nilfs_segbuf_fill_in_data_crc(segbuf, seed);
 337         }
 338 }
 339
 340 /*
 341  * BIO operations
 342  */
 343 static void nilfs_end_bio_write(struct bio *bio)
 344 {
 345         struct nilfs_segment_buffer *segbuf = bio->bi_private;
 346
 347         if (bio->bi_status)
 348                 atomic_inc(&segbuf->sb_err);
 349
 350         bio_put(bio);
 351         complete(&segbuf->sb_bio_event);
 352 }
 353
 354 static int nilfs_segbuf_submit_bio(struct nilfs_segment_buffer *segbuf,
 355                                    struct nilfs_write_info *wi, int mode,
 356                                    int mode_flags)
 357 {
 358         struct bio *bio = wi->bio;
 359         int err;
 360
 361         if (segbuf->sb_nbio > 0 &&
 362             bdi_write_congested(segbuf->sb_super->s_bdi)) {
 363                 wait_for_completion(&segbuf->sb_bio_event);
 364                 segbuf->sb_nbio--;
 365                 if (unlikely(atomic_read(&segbuf->sb_err))) {
 366                         bio_put(bio);
 367                         err = -EIO;
 368                         goto failed;
 369                 }
 370         }
 371
 372         bio->bi_end_io = nilfs_end_bio_write;
 373         bio->bi_private = segbuf;
 374         bio_set_op_attrs(bio, mode, mode_flags);
 375         submit_bio(bio);
 376         segbuf->sb_nbio++;
 377
 378         wi->bio = NULL;
 379         wi->rest_blocks -= wi->end - wi->start;
 380         wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
 381         wi->start = wi->end;
 382         return 0;
 383
 384  failed:
 385         wi->bio = NULL;
 386         return err;
 387 }
 388
 389 /**
 390  * nilfs_alloc_seg_bio - allocate a new bio for writing log
 391  * @nilfs: nilfs object
 392  * @start: start block number of the bio
 393  * @nr_vecs: request size of page vector.
 394  *
 395  * Return Value: On success, pointer to the struct bio is returned.
 396  * On error, NULL is returned.
 397  */
 398 static struct bio *nilfs_alloc_seg_bio(struct the_nilfs *nilfs, sector_t start,
 399                                        int nr_vecs)
 400 {
 401         struct bio *bio;
 402
 403         bio = bio_alloc(GFP_NOIO, nr_vecs);
 404         if (bio == NULL) {
 405                 while (!bio && (nr_vecs >>= 1))
 406                         bio = bio_alloc(GFP_NOIO, nr_vecs);
 407         }
 408         if (likely(bio)) {
 409                 bio_set_dev(bio, nilfs->ns_bdev);
 410                 bio->bi_iter.bi_sector =
 411                         start << (nilfs->ns_blocksize_bits - 9);
 412         }
 413         return bio;
 414 }
 415
 416 static void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *segbuf,
 417                                        struct nilfs_write_info *wi)
 418 {
 419         wi->bio = NULL;
 420         wi->rest_blocks = segbuf->sb_sum.nblocks;
 421         wi->max_pages = BIO_MAX_PAGES;
 422         wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
 423         wi->start = wi->end = 0;
 424         wi->blocknr = segbuf->sb_pseg_start;
 425 }
 426
 427 static int nilfs_segbuf_submit_bh(struct nilfs_segment_buffer *segbuf,
 428                                   struct nilfs_write_info *wi,
 429                                   struct buffer_head *bh, int mode)
 430 {
 431         int len, err;
 432
 433         BUG_ON(wi->nr_vecs <= 0);
 434  repeat:
 435         if (!wi->bio) {
 436                 wi->bio = nilfs_alloc_seg_bio(wi->nilfs, wi->blocknr + wi->end,
 437                                               wi->nr_vecs);
 438                 if (unlikely(!wi->bio))
 439                         return -ENOMEM;
 440         }
 441
 442         len = bio_add_page(wi->bio, bh->b_page, bh->b_size, bh_offset(bh));
 443         if (len == bh->b_size) {
 444                 wi->end++;
 445                 return 0;
 446         }
 447         /* bio is FULL */
 448         err = nilfs_segbuf_submit_bio(segbuf, wi, mode, 0);
 449         /* never submit current bh */
 450         if (likely(!err))
 451                 goto repeat;
 452         return err;
 453 }
 454
 455 /**
 456  * nilfs_segbuf_write - submit write requests of a log
 457  * @segbuf: buffer storing a log to be written
 458  * @nilfs: nilfs object
 459  *
 460  * Return Value: On Success, 0 is returned. On Error, one of the following
 461  * negative error code is returned.
 462  *
 463  * %-EIO - I/O error
 464  *
 465  * %-ENOMEM - Insufficient memory available.
 466  */
 467 static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
 468                               struct the_nilfs *nilfs)
 469 {
 470         struct nilfs_write_info wi;
 471         struct buffer_head *bh;
 472         int res = 0;
 473
 474         wi.nilfs = nilfs;
 475         nilfs_segbuf_prepare_write(segbuf, &wi);
 476
 477         list_for_each_entry(bh, &segbuf->sb_segsum_buffers, b_assoc_buffers) {
 478                 res = nilfs_segbuf_submit_bh(segbuf, &wi, bh, REQ_OP_WRITE);
 479                 if (unlikely(res))
 480                         goto failed_bio;
 481         }
 482
 483         list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
 484                 res = nilfs_segbuf_submit_bh(segbuf, &wi, bh, REQ_OP_WRITE);
 485                 if (unlikely(res))
 486                         goto failed_bio;
 487         }
 488
 489         if (wi.bio) {
 490                 /*
 491                  * Last BIO is always sent through the following
 492                  * submission.
 493                  */
 494                 res = nilfs_segbuf_submit_bio(segbuf, &wi, REQ_OP_WRITE,
 495                                               REQ_SYNC);
 496         }
 497
 498  failed_bio:
 499         return res;
 500 }
 501
 502 /**
 503  * nilfs_segbuf_wait - wait for completion of requested BIOs
 504  * @segbuf: segment buffer
 505  *
 506  * Return Value: On Success, 0 is returned. On Error, one of the following
 507  * negative error code is returned.
 508  *
 509  * %-EIO - I/O error
 510  */
 511 static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf)
 512 {
 513         int err = 0;
 514
 515         if (!segbuf->sb_nbio)
 516                 return 0;
 517
 518         do {
 519                 wait_for_completion(&segbuf->sb_bio_event);
 520         } while (--segbuf->sb_nbio > 0);
 521
 522         if (unlikely(atomic_read(&segbuf->sb_err) > 0)) {
 523                 nilfs_msg(segbuf->sb_super, KERN_ERR,
 524                           "I/O error writing log (start-blocknr=%llu, block-count=%lu) in segment %llu",
 525                           (unsigned long long)segbuf->sb_pseg_start,
 526                           segbuf->sb_sum.nblocks,
 527                           (unsigned long long)segbuf->sb_segnum);
 528                 err = -EIO;
 529         }
 530         return err;
 531 }