git.oblomov.eu Git - linux-2.6/blob - 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 "page.h"
  28 #include "segbuf.h"
  29 #include "seglist.h"
  30
  31
  32 static struct kmem_cache *nilfs_segbuf_cachep;
  33
  34 static void nilfs_segbuf_init_once(void *obj)
  35 {
  36         memset(obj, 0, sizeof(struct nilfs_segment_buffer));
  37 }
  38
  39 int __init nilfs_init_segbuf_cache(void)
  40 {
  41         nilfs_segbuf_cachep =
  42                 kmem_cache_create("nilfs2_segbuf_cache",
  43                                   sizeof(struct nilfs_segment_buffer),
  44                                   0, SLAB_RECLAIM_ACCOUNT,
  45                                   nilfs_segbuf_init_once);
  46
  47         return (nilfs_segbuf_cachep == NULL) ? -ENOMEM : 0;
  48 }
  49
  50 void nilfs_destroy_segbuf_cache(void)
  51 {
  52         kmem_cache_destroy(nilfs_segbuf_cachep);
  53 }
  54
  55 struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *sb)
  56 {
  57         struct nilfs_segment_buffer *segbuf;
  58
  59         segbuf = kmem_cache_alloc(nilfs_segbuf_cachep, GFP_NOFS);
  60         if (unlikely(!segbuf))
  61                 return NULL;
  62
  63         segbuf->sb_super = sb;
  64         INIT_LIST_HEAD(&segbuf->sb_list);
  65         INIT_LIST_HEAD(&segbuf->sb_segsum_buffers);
  66         INIT_LIST_HEAD(&segbuf->sb_payload_buffers);
  67         return segbuf;
  68 }
  69
  70 void nilfs_segbuf_free(struct nilfs_segment_buffer *segbuf)
  71 {
  72         kmem_cache_free(nilfs_segbuf_cachep, segbuf);
  73 }
  74
  75 void nilfs_segbuf_map(struct nilfs_segment_buffer *segbuf, __u64 segnum,
  76                      unsigned long offset, struct the_nilfs *nilfs)
  77 {
  78         segbuf->sb_segnum = segnum;
  79         nilfs_get_segment_range(nilfs, segnum, &segbuf->sb_fseg_start,
  80                                 &segbuf->sb_fseg_end);
  81
  82         segbuf->sb_pseg_start = segbuf->sb_fseg_start + offset;
  83         segbuf->sb_rest_blocks =
  84                 segbuf->sb_fseg_end - segbuf->sb_pseg_start + 1;
  85 }
  86
  87 void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *segbuf,
  88                                   __u64 nextnum, struct the_nilfs *nilfs)
  89 {
  90         segbuf->sb_nextnum = nextnum;
  91         segbuf->sb_sum.next = nilfs_get_segment_start_blocknr(nilfs, nextnum);
  92 }
  93
  94 int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *segbuf)
  95 {
  96         struct buffer_head *bh;
  97
  98         bh = sb_getblk(segbuf->sb_super,
  99                        segbuf->sb_pseg_start + segbuf->sb_sum.nsumblk);
 100         if (unlikely(!bh))
 101                 return -ENOMEM;
 102
 103         nilfs_segbuf_add_segsum_buffer(segbuf, bh);
 104         return 0;
 105 }
 106
 107 int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *segbuf,
 108                                 struct buffer_head **bhp)
 109 {
 110         struct buffer_head *bh;
 111
 112         bh = sb_getblk(segbuf->sb_super,
 113                        segbuf->sb_pseg_start + segbuf->sb_sum.nblocks);
 114         if (unlikely(!bh))
 115                 return -ENOMEM;
 116
 117         nilfs_segbuf_add_payload_buffer(segbuf, bh);
 118         *bhp = bh;
 119         return 0;
 120 }
 121
 122 int nilfs_segbuf_reset(struct nilfs_segment_buffer *segbuf, unsigned flags,
 123                        time_t ctime)
 124 {
 125         int err;
 126
 127         segbuf->sb_sum.nblocks = segbuf->sb_sum.nsumblk = 0;
 128         err = nilfs_segbuf_extend_segsum(segbuf);
 129         if (unlikely(err))
 130                 return err;
 131
 132         segbuf->sb_sum.flags = flags;
 133         segbuf->sb_sum.sumbytes = sizeof(struct nilfs_segment_summary);
 134         segbuf->sb_sum.nfinfo = segbuf->sb_sum.nfileblk = 0;
 135         segbuf->sb_sum.ctime = ctime;
 136
 137         segbuf->sb_io_error = 0;
 138         return 0;
 139 }
 140
 141 /*
 142  * Setup segument 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 }
 164
 165 /*
 166  * CRC calculation routines
 167  */
 168 void nilfs_segbuf_fill_in_segsum_crc(struct nilfs_segment_buffer *segbuf,
 169                                      u32 seed)
 170 {
 171         struct buffer_head *bh;
 172         struct nilfs_segment_summary *raw_sum;
 173         unsigned long size, bytes = segbuf->sb_sum.sumbytes;
 174         u32 crc;
 175
 176         bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
 177                         b_assoc_buffers);
 178
 179         raw_sum = (struct nilfs_segment_summary *)bh->b_data;
 180         size = min_t(unsigned long, bytes, bh->b_size);
 181         crc = crc32_le(seed,
 182                        (unsigned char *)raw_sum +
 183                        sizeof(raw_sum->ss_datasum) + sizeof(raw_sum->ss_sumsum),
 184                        size - (sizeof(raw_sum->ss_datasum) +
 185                                sizeof(raw_sum->ss_sumsum)));
 186
 187         list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
 188                                      b_assoc_buffers) {
 189                 bytes -= size;
 190                 size = min_t(unsigned long, bytes, bh->b_size);
 191                 crc = crc32_le(crc, bh->b_data, size);
 192         }
 193         raw_sum->ss_sumsum = cpu_to_le32(crc);
 194 }
 195
 196 void nilfs_segbuf_fill_in_data_crc(struct nilfs_segment_buffer *segbuf,
 197                                    u32 seed)
 198 {
 199         struct buffer_head *bh;
 200         struct nilfs_segment_summary *raw_sum;
 201         void *kaddr;
 202         u32 crc;
 203
 204         bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
 205                         b_assoc_buffers);
 206         raw_sum = (struct nilfs_segment_summary *)bh->b_data;
 207         crc = crc32_le(seed,
 208                        (unsigned char *)raw_sum + sizeof(raw_sum->ss_datasum),
 209                        bh->b_size - sizeof(raw_sum->ss_datasum));
 210
 211         list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
 212                                      b_assoc_buffers) {
 213                 crc = crc32_le(crc, bh->b_data, bh->b_size);
 214         }
 215         list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
 216                 kaddr = kmap_atomic(bh->b_page, KM_USER0);
 217                 crc = crc32_le(crc, kaddr + bh_offset(bh), bh->b_size);
 218                 kunmap_atomic(kaddr, KM_USER0);
 219         }
 220         raw_sum->ss_datasum = cpu_to_le32(crc);
 221 }
 222
 223 void nilfs_release_buffers(struct list_head *list)
 224 {
 225         struct buffer_head *bh, *n;
 226
 227         list_for_each_entry_safe(bh, n, list, b_assoc_buffers) {
 228                 list_del_init(&bh->b_assoc_buffers);
 229                 if (buffer_nilfs_allocated(bh)) {
 230                         struct page *clone_page = bh->b_page;
 231
 232                         /* remove clone page */
 233                         brelse(bh);
 234                         page_cache_release(clone_page); /* for each bh */
 235                         if (page_count(clone_page) <= 2) {
 236                                 lock_page(clone_page);
 237                                 nilfs_free_private_page(clone_page);
 238                         }
 239                         continue;
 240                 }
 241                 brelse(bh);
 242         }
 243 }
 244
 245 /*
 246  * BIO operations
 247  */
 248 static void nilfs_end_bio_write(struct bio *bio, int err)
 249 {
 250         const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
 251         struct nilfs_write_info *wi = bio->bi_private;
 252
 253         if (err == -EOPNOTSUPP) {
 254                 set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
 255                 bio_put(bio);
 256                 /* to be detected by submit_seg_bio() */
 257         }
 258
 259         if (!uptodate)
 260                 atomic_inc(&wi->err);
 261
 262         bio_put(bio);
 263         complete(&wi->bio_event);
 264 }
 265
 266 static int nilfs_submit_seg_bio(struct nilfs_write_info *wi, int mode)
 267 {
 268         struct bio *bio = wi->bio;
 269         int err;
 270
 271         if (wi->nbio > 0 && bdi_write_congested(wi->bdi)) {
 272                 wait_for_completion(&wi->bio_event);
 273                 wi->nbio--;
 274                 if (unlikely(atomic_read(&wi->err))) {
 275                         bio_put(bio);
 276                         err = -EIO;
 277                         goto failed;
 278                 }
 279         }
 280
 281         bio->bi_end_io = nilfs_end_bio_write;
 282         bio->bi_private = wi;
 283         bio_get(bio);
 284         submit_bio(mode, bio);
 285         if (bio_flagged(bio, BIO_EOPNOTSUPP)) {
 286                 bio_put(bio);
 287                 err = -EOPNOTSUPP;
 288                 goto failed;
 289         }
 290         wi->nbio++;
 291         bio_put(bio);
 292
 293         wi->bio = NULL;
 294         wi->rest_blocks -= wi->end - wi->start;
 295         wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
 296         wi->start = wi->end;
 297         return 0;
 298
 299  failed:
 300         wi->bio = NULL;
 301         return err;
 302 }
 303
 304 /**
 305  * nilfs_alloc_seg_bio - allocate a bio for writing segment.
 306  * @sb: super block
 307  * @start: beginning disk block number of this BIO.
 308  * @nr_vecs: request size of page vector.
 309  *
 310  * alloc_seg_bio() allocates a new BIO structure and initialize it.
 311  *
 312  * Return Value: On success, pointer to the struct bio is returned.
 313  * On error, NULL is returned.
 314  */
 315 static struct bio *nilfs_alloc_seg_bio(struct super_block *sb, sector_t start,
 316                                        int nr_vecs)
 317 {
 318         struct bio *bio;
 319
 320         bio = bio_alloc(GFP_NOWAIT, nr_vecs);
 321         if (bio == NULL) {
 322                 while (!bio && (nr_vecs >>= 1))
 323                         bio = bio_alloc(GFP_NOWAIT, nr_vecs);
 324         }
 325         if (likely(bio)) {
 326                 bio->bi_bdev = sb->s_bdev;
 327                 bio->bi_sector = (sector_t)start << (sb->s_blocksize_bits - 9);
 328         }
 329         return bio;
 330 }
 331
 332 void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *segbuf,
 333                                 struct nilfs_write_info *wi)
 334 {
 335         wi->bio = NULL;
 336         wi->rest_blocks = segbuf->sb_sum.nblocks;
 337         wi->max_pages = bio_get_nr_vecs(wi->sb->s_bdev);
 338         wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
 339         wi->start = wi->end = 0;
 340         wi->nbio = 0;
 341         wi->blocknr = segbuf->sb_pseg_start;
 342
 343         atomic_set(&wi->err, 0);
 344         init_completion(&wi->bio_event);
 345 }
 346
 347 static int nilfs_submit_bh(struct nilfs_write_info *wi, struct buffer_head *bh,
 348                            int mode)
 349 {
 350         int len, err;
 351
 352         BUG_ON(wi->nr_vecs <= 0);
 353  repeat:
 354         if (!wi->bio) {
 355                 wi->bio = nilfs_alloc_seg_bio(wi->sb, wi->blocknr + wi->end,
 356                                               wi->nr_vecs);
 357                 if (unlikely(!wi->bio))
 358                         return -ENOMEM;
 359         }
 360
 361         len = bio_add_page(wi->bio, bh->b_page, bh->b_size, bh_offset(bh));
 362         if (len == bh->b_size) {
 363                 wi->end++;
 364                 return 0;
 365         }
 366         /* bio is FULL */
 367         err = nilfs_submit_seg_bio(wi, mode);
 368         /* never submit current bh */
 369         if (likely(!err))
 370                 goto repeat;
 371         return err;
 372 }
 373
 374 int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
 375                        struct nilfs_write_info *wi)
 376 {
 377         struct buffer_head *bh;
 378         int res, rw = WRITE;
 379
 380         list_for_each_entry(bh, &segbuf->sb_segsum_buffers, b_assoc_buffers) {
 381                 res = nilfs_submit_bh(wi, bh, rw);
 382                 if (unlikely(res))
 383                         goto failed_bio;
 384         }
 385
 386         list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
 387                 res = nilfs_submit_bh(wi, bh, rw);
 388                 if (unlikely(res))
 389                         goto failed_bio;
 390         }
 391
 392         if (wi->bio) {
 393                 /*
 394                  * Last BIO is always sent through the following
 395                  * submission.
 396                  */
 397                 rw |= (1 << BIO_RW_SYNCIO);
 398                 res = nilfs_submit_seg_bio(wi, rw);
 399                 if (unlikely(res))
 400                         goto failed_bio;
 401         }
 402
 403         res = 0;
 404  out:
 405         return res;
 406
 407  failed_bio:
 408         atomic_inc(&wi->err);
 409         goto out;
 410 }
 411
 412 /**
 413  * nilfs_segbuf_wait - wait for completion of requested BIOs
 414  * @wi: nilfs_write_info
 415  *
 416  * Return Value: On Success, 0 is returned. On Error, one of the following
 417  * negative error code is returned.
 418  *
 419  * %-EIO - I/O error
 420  */
 421 int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf,
 422                       struct nilfs_write_info *wi)
 423 {
 424         int err = 0;
 425
 426         if (!wi->nbio)
 427                 return 0;
 428
 429         do {
 430                 wait_for_completion(&wi->bio_event);
 431         } while (--wi->nbio > 0);
 432
 433         if (unlikely(atomic_read(&wi->err) > 0)) {
 434                 printk(KERN_ERR "NILFS: IO error writing segment\n");
 435                 err = -EIO;
 436                 segbuf->sb_io_error = 1;
 437         }
 438         return err;
 439 }