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