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  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  *
  20  * Written by Ryusuke Konishi <ryusuke@osrg.net>
  21  *
  22  */
  23
  24 #include <linux/buffer_head.h>
  25 #include <linux/writeback.h>
  26 #include <linux/crc32.h>
  27 #include <linux/backing-dev.h>
  28 #include "page.h"
  29 #include "segbuf.h"
  30
  31
  32 struct nilfs_write_info {
  33         struct the_nilfs       *nilfs;
  34         struct bio             *bio;
  35         int                     start, end; /* The region to be submitted */
  36         int                     rest_blocks;
  37         int                     max_pages;
  38         int                     nr_vecs;
  39         sector_t                blocknr;
  40 };
  41
  42
  43 static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
  44                               struct the_nilfs *nilfs);
  45 static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf);
  46
  47
  48 static struct kmem_cache *nilfs_segbuf_cachep;
  49
  50 static void nilfs_segbuf_init_once(void *obj)
  51 {
  52         memset(obj, 0, sizeof(struct nilfs_segment_buffer));
  53 }
  54
  55 int __init nilfs_init_segbuf_cache(void)
  56 {
  57         nilfs_segbuf_cachep =
  58                 kmem_cache_create("nilfs2_segbuf_cache",
  59                                   sizeof(struct nilfs_segment_buffer),
  60                                   0, SLAB_RECLAIM_ACCOUNT,
  61                                   nilfs_segbuf_init_once);
  62
  63         return (nilfs_segbuf_cachep == NULL) ? -ENOMEM : 0;
  64 }
  65
  66 void nilfs_destroy_segbuf_cache(void)
  67 {
  68         kmem_cache_destroy(nilfs_segbuf_cachep);
  69 }
  70
  71 struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *sb)
  72 {
  73         struct nilfs_segment_buffer *segbuf;
  74
  75         segbuf = kmem_cache_alloc(nilfs_segbuf_cachep, GFP_NOFS);
  76         if (unlikely(!segbuf))
  77                 return NULL;
  78
  79         segbuf->sb_super = sb;
  80         INIT_LIST_HEAD(&segbuf->sb_list);
  81         INIT_LIST_HEAD(&segbuf->sb_segsum_buffers);
  82         INIT_LIST_HEAD(&segbuf->sb_payload_buffers);
  83
  84         init_completion(&segbuf->sb_bio_event);
  85         atomic_set(&segbuf->sb_err, 0);
  86         segbuf->sb_nbio = 0;
  87
  88         return segbuf;
  89 }
  90
  91 void nilfs_segbuf_free(struct nilfs_segment_buffer *segbuf)
  92 {
  93         kmem_cache_free(nilfs_segbuf_cachep, segbuf);
  94 }
  95
  96 void nilfs_segbuf_map(struct nilfs_segment_buffer *segbuf, __u64 segnum,
  97                      unsigned long offset, struct the_nilfs *nilfs)
  98 {
  99         segbuf->sb_segnum = segnum;
 100         nilfs_get_segment_range(nilfs, segnum, &segbuf->sb_fseg_start,
 101                                 &segbuf->sb_fseg_end);
 102
 103         segbuf->sb_pseg_start = segbuf->sb_fseg_start + offset;
 104         segbuf->sb_rest_blocks =
 105                 segbuf->sb_fseg_end - segbuf->sb_pseg_start + 1;
 106 }
 107
 108 /**
 109  * nilfs_segbuf_map_cont - map a new log behind a given log
 110  * @segbuf: new segment buffer
 111  * @prev: segment buffer containing a log to be continued
 112  */
 113 void nilfs_segbuf_map_cont(struct nilfs_segment_buffer *segbuf,
 114                            struct nilfs_segment_buffer *prev)
 115 {
 116         segbuf->sb_segnum = prev->sb_segnum;
 117         segbuf->sb_fseg_start = prev->sb_fseg_start;
 118         segbuf->sb_fseg_end = prev->sb_fseg_end;
 119         segbuf->sb_pseg_start = prev->sb_pseg_start + prev->sb_sum.nblocks;
 120         segbuf->sb_rest_blocks =
 121                 segbuf->sb_fseg_end - segbuf->sb_pseg_start + 1;
 122 }
 123
 124 void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *segbuf,
 125                                   __u64 nextnum, struct the_nilfs *nilfs)
 126 {
 127         segbuf->sb_nextnum = nextnum;
 128         segbuf->sb_sum.next = nilfs_get_segment_start_blocknr(nilfs, nextnum);
 129 }
 130
 131 int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *segbuf)
 132 {
 133         struct buffer_head *bh;
 134
 135         bh = sb_getblk(segbuf->sb_super,
 136                        segbuf->sb_pseg_start + segbuf->sb_sum.nsumblk);
 137         if (unlikely(!bh))
 138                 return -ENOMEM;
 139
 140         nilfs_segbuf_add_segsum_buffer(segbuf, bh);
 141         return 0;
 142 }
 143
 144 int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *segbuf,
 145                                 struct buffer_head **bhp)
 146 {
 147         struct buffer_head *bh;
 148
 149         bh = sb_getblk(segbuf->sb_super,
 150                        segbuf->sb_pseg_start + segbuf->sb_sum.nblocks);
 151         if (unlikely(!bh))
 152                 return -ENOMEM;
 153
 154         nilfs_segbuf_add_payload_buffer(segbuf, bh);
 155         *bhp = bh;
 156         return 0;
 157 }
 158
 159 int nilfs_segbuf_reset(struct nilfs_segment_buffer *segbuf, unsigned flags,
 160                        time_t ctime)
 161 {
 162         int err;
 163
 164         segbuf->sb_sum.nblocks = segbuf->sb_sum.nsumblk = 0;
 165         err = nilfs_segbuf_extend_segsum(segbuf);
 166         if (unlikely(err))
 167                 return err;
 168
 169         segbuf->sb_sum.flags = flags;
 170         segbuf->sb_sum.sumbytes = sizeof(struct nilfs_segment_summary);
 171         segbuf->sb_sum.nfinfo = segbuf->sb_sum.nfileblk = 0;
 172         segbuf->sb_sum.ctime = ctime;
 173         return 0;
 174 }
 175
 176 /*
 177  * Setup segment summary
 178  */
 179 void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *segbuf)
 180 {
 181         struct nilfs_segment_summary *raw_sum;
 182         struct buffer_head *bh_sum;
 183
 184         bh_sum = list_entry(segbuf->sb_segsum_buffers.next,
 185                             struct buffer_head, b_assoc_buffers);
 186         raw_sum = (struct nilfs_segment_summary *)bh_sum->b_data;
 187
 188         raw_sum->ss_magic    = cpu_to_le32(NILFS_SEGSUM_MAGIC);
 189         raw_sum->ss_bytes    = cpu_to_le16(sizeof(*raw_sum));
 190         raw_sum->ss_flags    = cpu_to_le16(segbuf->sb_sum.flags);
 191         raw_sum->ss_seq      = cpu_to_le64(segbuf->sb_sum.seg_seq);
 192         raw_sum->ss_create   = cpu_to_le64(segbuf->sb_sum.ctime);
 193         raw_sum->ss_next     = cpu_to_le64(segbuf->sb_sum.next);
 194         raw_sum->ss_nblocks  = cpu_to_le32(segbuf->sb_sum.nblocks);
 195         raw_sum->ss_nfinfo   = cpu_to_le32(segbuf->sb_sum.nfinfo);
 196         raw_sum->ss_sumbytes = cpu_to_le32(segbuf->sb_sum.sumbytes);
 197         raw_sum->ss_pad      = 0;
 198 }
 199
 200 /*
 201  * CRC calculation routines
 202  */
 203 void nilfs_segbuf_fill_in_segsum_crc(struct nilfs_segment_buffer *segbuf,
 204                                      u32 seed)
 205 {
 206         struct buffer_head *bh;
 207         struct nilfs_segment_summary *raw_sum;
 208         unsigned long size, bytes = segbuf->sb_sum.sumbytes;
 209         u32 crc;
 210
 211         bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
 212                         b_assoc_buffers);
 213
 214         raw_sum = (struct nilfs_segment_summary *)bh->b_data;
 215         size = min_t(unsigned long, bytes, bh->b_size);
 216         crc = crc32_le(seed,
 217                        (unsigned char *)raw_sum +
 218                        sizeof(raw_sum->ss_datasum) + sizeof(raw_sum->ss_sumsum),
 219                        size - (sizeof(raw_sum->ss_datasum) +
 220                                sizeof(raw_sum->ss_sumsum)));
 221
 222         list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
 223                                      b_assoc_buffers) {
 224                 bytes -= size;
 225                 size = min_t(unsigned long, bytes, bh->b_size);
 226                 crc = crc32_le(crc, bh->b_data, size);
 227         }
 228         raw_sum->ss_sumsum = cpu_to_le32(crc);
 229 }
 230
 231 void nilfs_segbuf_fill_in_data_crc(struct nilfs_segment_buffer *segbuf,
 232                                    u32 seed)
 233 {
 234         struct buffer_head *bh;
 235         struct nilfs_segment_summary *raw_sum;
 236         void *kaddr;
 237         u32 crc;
 238
 239         bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
 240                         b_assoc_buffers);
 241         raw_sum = (struct nilfs_segment_summary *)bh->b_data;
 242         crc = crc32_le(seed,
 243                        (unsigned char *)raw_sum + sizeof(raw_sum->ss_datasum),
 244                        bh->b_size - sizeof(raw_sum->ss_datasum));
 245
 246         list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
 247                                      b_assoc_buffers) {
 248                 crc = crc32_le(crc, bh->b_data, bh->b_size);
 249         }
 250         list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
 251                 kaddr = kmap_atomic(bh->b_page, KM_USER0);
 252                 crc = crc32_le(crc, kaddr + bh_offset(bh), bh->b_size);
 253                 kunmap_atomic(kaddr, KM_USER0);
 254         }
 255         raw_sum->ss_datasum = cpu_to_le32(crc);
 256 }
 257
 258 static void nilfs_release_buffers(struct list_head *list)
 259 {
 260         struct buffer_head *bh, *n;
 261
 262         list_for_each_entry_safe(bh, n, list, b_assoc_buffers) {
 263                 list_del_init(&bh->b_assoc_buffers);
 264                 if (buffer_nilfs_allocated(bh)) {
 265                         struct page *clone_page = bh->b_page;
 266
 267                         /* remove clone page */
 268                         brelse(bh);
 269                         page_cache_release(clone_page); /* for each bh */
 270                         if (page_count(clone_page) <= 2) {
 271                                 lock_page(clone_page);
 272                                 nilfs_free_private_page(clone_page);
 273                         }
 274                         continue;
 275                 }
 276                 brelse(bh);
 277         }
 278 }
 279
 280 static void nilfs_segbuf_clear(struct nilfs_segment_buffer *segbuf)
 281 {
 282         nilfs_release_buffers(&segbuf->sb_segsum_buffers);
 283         nilfs_release_buffers(&segbuf->sb_payload_buffers);
 284 }
 285
 286 /*
 287  * Iterators for segment buffers
 288  */
 289 void nilfs_clear_logs(struct list_head *logs)
 290 {
 291         struct nilfs_segment_buffer *segbuf;
 292
 293         list_for_each_entry(segbuf, logs, sb_list)
 294                 nilfs_segbuf_clear(segbuf);
 295 }
 296
 297 void nilfs_truncate_logs(struct list_head *logs,
 298                          struct nilfs_segment_buffer *last)
 299 {
 300         struct nilfs_segment_buffer *n, *segbuf;
 301
 302         segbuf = list_prepare_entry(last, logs, sb_list);
 303         list_for_each_entry_safe_continue(segbuf, n, logs, sb_list) {
 304                 list_del_init(&segbuf->sb_list);
 305                 nilfs_segbuf_clear(segbuf);
 306                 nilfs_segbuf_free(segbuf);
 307         }
 308 }
 309
 310 int nilfs_write_logs(struct list_head *logs, struct the_nilfs *nilfs)
 311 {
 312         struct nilfs_segment_buffer *segbuf;
 313         int ret = 0;
 314
 315         list_for_each_entry(segbuf, logs, sb_list) {
 316                 ret = nilfs_segbuf_write(segbuf, nilfs);
 317                 if (ret)
 318                         break;
 319         }
 320         return ret;
 321 }
 322
 323 int nilfs_wait_on_logs(struct list_head *logs)
 324 {
 325         struct nilfs_segment_buffer *segbuf;
 326         int err, ret = 0;
 327
 328         list_for_each_entry(segbuf, logs, sb_list) {
 329                 err = nilfs_segbuf_wait(segbuf);
 330                 if (err && !ret)
 331                         ret = err;
 332         }
 333         return ret;
 334 }
 335
 336 /*
 337  * BIO operations
 338  */
 339 static void nilfs_end_bio_write(struct bio *bio, int err)
 340 {
 341         const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
 342         struct nilfs_segment_buffer *segbuf = bio->bi_private;
 343
 344         if (err == -EOPNOTSUPP) {
 345                 set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
 346                 bio_put(bio);
 347                 /* to be detected by submit_seg_bio() */
 348         }
 349
 350         if (!uptodate)
 351                 atomic_inc(&segbuf->sb_err);
 352
 353         bio_put(bio);
 354         complete(&segbuf->sb_bio_event);
 355 }
 356
 357 static int nilfs_segbuf_submit_bio(struct nilfs_segment_buffer *segbuf,
 358                                    struct nilfs_write_info *wi, int mode)
 359 {
 360         struct bio *bio = wi->bio;
 361         int err;
 362
 363         if (segbuf->sb_nbio > 0 && bdi_write_congested(wi->nilfs->ns_bdi)) {
 364                 wait_for_completion(&segbuf->sb_bio_event);
 365                 segbuf->sb_nbio--;
 366                 if (unlikely(atomic_read(&segbuf->sb_err))) {
 367                         bio_put(bio);
 368                         err = -EIO;
 369                         goto failed;
 370                 }
 371         }
 372
 373         bio->bi_end_io = nilfs_end_bio_write;
 374         bio->bi_private = segbuf;
 375         bio_get(bio);
 376         submit_bio(mode, bio);
 377         if (bio_flagged(bio, BIO_EOPNOTSUPP)) {
 378                 bio_put(bio);
 379                 err = -EOPNOTSUPP;
 380                 goto failed;
 381         }
 382         segbuf->sb_nbio++;
 383         bio_put(bio);
 384
 385         wi->bio = NULL;
 386         wi->rest_blocks -= wi->end - wi->start;
 387         wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
 388         wi->start = wi->end;
 389         return 0;
 390
 391  failed:
 392         wi->bio = NULL;
 393         return err;
 394 }
 395
 396 /**
 397  * nilfs_alloc_seg_bio - allocate a new bio for writing log
 398  * @nilfs: nilfs object
 399  * @start: start block number of the bio
 400  * @nr_vecs: request size of page vector.
 401  *
 402  * Return Value: On success, pointer to the struct bio is returned.
 403  * On error, NULL is returned.
 404  */
 405 static struct bio *nilfs_alloc_seg_bio(struct the_nilfs *nilfs, sector_t start,
 406                                        int nr_vecs)
 407 {
 408         struct bio *bio;
 409
 410         bio = bio_alloc(GFP_NOIO, nr_vecs);
 411         if (bio == NULL) {
 412                 while (!bio && (nr_vecs >>= 1))
 413                         bio = bio_alloc(GFP_NOIO, nr_vecs);
 414         }
 415         if (likely(bio)) {
 416                 bio->bi_bdev = nilfs->ns_bdev;
 417                 bio->bi_sector = start << (nilfs->ns_blocksize_bits - 9);
 418         }
 419         return bio;
 420 }
 421
 422 static void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *segbuf,
 423                                        struct nilfs_write_info *wi)
 424 {
 425         wi->bio = NULL;
 426         wi->rest_blocks = segbuf->sb_sum.nblocks;
 427         wi->max_pages = bio_get_nr_vecs(wi->nilfs->ns_bdev);
 428         wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
 429         wi->start = wi->end = 0;
 430         wi->blocknr = segbuf->sb_pseg_start;
 431 }
 432
 433 static int nilfs_segbuf_submit_bh(struct nilfs_segment_buffer *segbuf,
 434                                   struct nilfs_write_info *wi,
 435                                   struct buffer_head *bh, int mode)
 436 {
 437         int len, err;
 438
 439         BUG_ON(wi->nr_vecs <= 0);
 440  repeat:
 441         if (!wi->bio) {
 442                 wi->bio = nilfs_alloc_seg_bio(wi->nilfs, wi->blocknr + wi->end,
 443                                               wi->nr_vecs);
 444                 if (unlikely(!wi->bio))
 445                         return -ENOMEM;
 446         }
 447
 448         len = bio_add_page(wi->bio, bh->b_page, bh->b_size, bh_offset(bh));
 449         if (len == bh->b_size) {
 450                 wi->end++;
 451                 return 0;
 452         }
 453         /* bio is FULL */
 454         err = nilfs_segbuf_submit_bio(segbuf, wi, mode);
 455         /* never submit current bh */
 456         if (likely(!err))
 457                 goto repeat;
 458         return err;
 459 }
 460
 461 /**
 462  * nilfs_segbuf_write - submit write requests of a log
 463  * @segbuf: buffer storing a log to be written
 464  * @nilfs: nilfs object
 465  *
 466  * Return Value: On Success, 0 is returned. On Error, one of the following
 467  * negative error code is returned.
 468  *
 469  * %-EIO - I/O error
 470  *
 471  * %-ENOMEM - Insufficient memory available.
 472  */
 473 static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
 474                               struct the_nilfs *nilfs)
 475 {
 476         struct nilfs_write_info wi;
 477         struct buffer_head *bh;
 478         int res = 0, rw = WRITE;
 479
 480         wi.nilfs = nilfs;
 481         nilfs_segbuf_prepare_write(segbuf, &wi);
 482
 483         list_for_each_entry(bh, &segbuf->sb_segsum_buffers, b_assoc_buffers) {
 484                 res = nilfs_segbuf_submit_bh(segbuf, &wi, bh, rw);
 485                 if (unlikely(res))
 486                         goto failed_bio;
 487         }
 488
 489         list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
 490                 res = nilfs_segbuf_submit_bh(segbuf, &wi, bh, rw);
 491                 if (unlikely(res))
 492                         goto failed_bio;
 493         }
 494
 495         if (wi.bio) {
 496                 /*
 497                  * Last BIO is always sent through the following
 498                  * submission.
 499                  */
 500                 rw |= (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_UNPLUG);
 501                 res = nilfs_segbuf_submit_bio(segbuf, &wi, rw);
 502         }
 503
 504  failed_bio:
 505         return res;
 506 }
 507
 508 /**
 509  * nilfs_segbuf_wait - wait for completion of requested BIOs
 510  * @segbuf: segment buffer
 511  *
 512  * Return Value: On Success, 0 is returned. On Error, one of the following
 513  * negative error code is returned.
 514  *
 515  * %-EIO - I/O error
 516  */
 517 static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf)
 518 {
 519         int err = 0;
 520
 521         if (!segbuf->sb_nbio)
 522                 return 0;
 523
 524         do {
 525                 wait_for_completion(&segbuf->sb_bio_event);
 526         } while (--segbuf->sb_nbio > 0);
 527
 528         if (unlikely(atomic_read(&segbuf->sb_err) > 0)) {
 529                 printk(KERN_ERR "NILFS: IO error writing segment\n");
 530                 err = -EIO;
 531         }
 532         return err;
 533 }