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         segbuf->sb_segent = NULL;
  68         return segbuf;
  69 }
  70
  71 void nilfs_segbuf_free(struct nilfs_segment_buffer *segbuf)
  72 {
  73         struct nilfs_segment_entry *ent = segbuf->sb_segent;
  74
  75         if (ent != NULL && list_empty(&ent->list)) {
  76                 /* free isolated segment list head */
  77                 nilfs_free_segment_entry(segbuf->sb_segent);
  78                 segbuf->sb_segent = NULL;
  79         }
  80         kmem_cache_free(nilfs_segbuf_cachep, segbuf);
  81 }
  82
  83 int nilfs_segbuf_map(struct nilfs_segment_buffer *segbuf, __u64 segnum,
  84                      unsigned long offset, struct the_nilfs *nilfs)
  85 {
  86         struct nilfs_segment_entry *ent;
  87
  88         segbuf->sb_segnum = segnum;
  89         nilfs_get_segment_range(nilfs, segnum, &segbuf->sb_fseg_start,
  90                                 &segbuf->sb_fseg_end);
  91
  92         segbuf->sb_pseg_start = segbuf->sb_fseg_start + offset;
  93         segbuf->sb_rest_blocks =
  94                 segbuf->sb_fseg_end - segbuf->sb_pseg_start + 1;
  95
  96         /* Attach a segment list head */
  97         ent = segbuf->sb_segent;
  98         if (ent == NULL) {
  99                 segbuf->sb_segent = nilfs_alloc_segment_entry(segnum);
 100                 if (unlikely(!segbuf->sb_segent))
 101                         return -ENOMEM;
 102         } else {
 103                 BUG_ON(ent->bh_su || !list_empty(&ent->list));
 104                 ent->segnum = segnum;
 105         }
 106         return 0;
 107 }
 108
 109 void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *segbuf,
 110                                   __u64 nextnum, struct the_nilfs *nilfs)
 111 {
 112         segbuf->sb_nextnum = nextnum;
 113         segbuf->sb_sum.next = nilfs_get_segment_start_blocknr(nilfs, nextnum);
 114 }
 115
 116 int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *segbuf)
 117 {
 118         struct buffer_head *bh;
 119
 120         bh = sb_getblk(segbuf->sb_super,
 121                        segbuf->sb_pseg_start + segbuf->sb_sum.nsumblk);
 122         if (unlikely(!bh))
 123                 return -ENOMEM;
 124
 125         nilfs_segbuf_add_segsum_buffer(segbuf, bh);
 126         return 0;
 127 }
 128
 129 int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *segbuf,
 130                                 struct buffer_head **bhp)
 131 {
 132         struct buffer_head *bh;
 133
 134         bh = sb_getblk(segbuf->sb_super,
 135                        segbuf->sb_pseg_start + segbuf->sb_sum.nblocks);
 136         if (unlikely(!bh))
 137                 return -ENOMEM;
 138
 139         nilfs_segbuf_add_payload_buffer(segbuf, bh);
 140         *bhp = bh;
 141         return 0;
 142 }
 143
 144 int nilfs_segbuf_reset(struct nilfs_segment_buffer *segbuf, unsigned flags,
 145                        time_t ctime)
 146 {
 147         int err;
 148
 149         segbuf->sb_sum.nblocks = segbuf->sb_sum.nsumblk = 0;
 150         err = nilfs_segbuf_extend_segsum(segbuf);
 151         if (unlikely(err))
 152                 return err;
 153
 154         segbuf->sb_sum.flags = flags;
 155         segbuf->sb_sum.sumbytes = sizeof(struct nilfs_segment_summary);
 156         segbuf->sb_sum.nfinfo = segbuf->sb_sum.nfileblk = 0;
 157         segbuf->sb_sum.ctime = ctime;
 158
 159         segbuf->sb_io_error = 0;
 160         return 0;
 161 }
 162
 163 /*
 164  * Setup segument summary
 165  */
 166 void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *segbuf)
 167 {
 168         struct nilfs_segment_summary *raw_sum;
 169         struct buffer_head *bh_sum;
 170
 171         bh_sum = list_entry(segbuf->sb_segsum_buffers.next,
 172                             struct buffer_head, b_assoc_buffers);
 173         raw_sum = (struct nilfs_segment_summary *)bh_sum->b_data;
 174
 175         raw_sum->ss_magic    = cpu_to_le32(NILFS_SEGSUM_MAGIC);
 176         raw_sum->ss_bytes    = cpu_to_le16(sizeof(*raw_sum));
 177         raw_sum->ss_flags    = cpu_to_le16(segbuf->sb_sum.flags);
 178         raw_sum->ss_seq      = cpu_to_le64(segbuf->sb_sum.seg_seq);
 179         raw_sum->ss_create   = cpu_to_le64(segbuf->sb_sum.ctime);
 180         raw_sum->ss_next     = cpu_to_le64(segbuf->sb_sum.next);
 181         raw_sum->ss_nblocks  = cpu_to_le32(segbuf->sb_sum.nblocks);
 182         raw_sum->ss_nfinfo   = cpu_to_le32(segbuf->sb_sum.nfinfo);
 183         raw_sum->ss_sumbytes = cpu_to_le32(segbuf->sb_sum.sumbytes);
 184         raw_sum->ss_pad      = 0;
 185 }
 186
 187 /*
 188  * CRC calculation routines
 189  */
 190 void nilfs_segbuf_fill_in_segsum_crc(struct nilfs_segment_buffer *segbuf,
 191                                      u32 seed)
 192 {
 193         struct buffer_head *bh;
 194         struct nilfs_segment_summary *raw_sum;
 195         unsigned long size, bytes = segbuf->sb_sum.sumbytes;
 196         u32 crc;
 197
 198         bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
 199                         b_assoc_buffers);
 200
 201         raw_sum = (struct nilfs_segment_summary *)bh->b_data;
 202         size = min_t(unsigned long, bytes, bh->b_size);
 203         crc = crc32_le(seed,
 204                        (unsigned char *)raw_sum +
 205                        sizeof(raw_sum->ss_datasum) + sizeof(raw_sum->ss_sumsum),
 206                        size - (sizeof(raw_sum->ss_datasum) +
 207                                sizeof(raw_sum->ss_sumsum)));
 208
 209         list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
 210                                      b_assoc_buffers) {
 211                 bytes -= size;
 212                 size = min_t(unsigned long, bytes, bh->b_size);
 213                 crc = crc32_le(crc, bh->b_data, size);
 214         }
 215         raw_sum->ss_sumsum = cpu_to_le32(crc);
 216 }
 217
 218 void nilfs_segbuf_fill_in_data_crc(struct nilfs_segment_buffer *segbuf,
 219                                    u32 seed)
 220 {
 221         struct buffer_head *bh;
 222         struct nilfs_segment_summary *raw_sum;
 223         void *kaddr;
 224         u32 crc;
 225
 226         bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
 227                         b_assoc_buffers);
 228         raw_sum = (struct nilfs_segment_summary *)bh->b_data;
 229         crc = crc32_le(seed,
 230                        (unsigned char *)raw_sum + sizeof(raw_sum->ss_datasum),
 231                        bh->b_size - sizeof(raw_sum->ss_datasum));
 232
 233         list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
 234                                      b_assoc_buffers) {
 235                 crc = crc32_le(crc, bh->b_data, bh->b_size);
 236         }
 237         list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
 238                 kaddr = kmap_atomic(bh->b_page, KM_USER0);
 239                 crc = crc32_le(crc, kaddr + bh_offset(bh), bh->b_size);
 240                 kunmap_atomic(kaddr, KM_USER0);
 241         }
 242         raw_sum->ss_datasum = cpu_to_le32(crc);
 243 }
 244
 245 void nilfs_release_buffers(struct list_head *list)
 246 {
 247         struct buffer_head *bh, *n;
 248
 249         list_for_each_entry_safe(bh, n, list, b_assoc_buffers) {
 250                 list_del_init(&bh->b_assoc_buffers);
 251                 if (buffer_nilfs_allocated(bh)) {
 252                         struct page *clone_page = bh->b_page;
 253
 254                         /* remove clone page */
 255                         brelse(bh);
 256                         page_cache_release(clone_page); /* for each bh */
 257                         if (page_count(clone_page) <= 2) {
 258                                 lock_page(clone_page);
 259                                 nilfs_free_private_page(clone_page);
 260                         }
 261                         continue;
 262                 }
 263                 brelse(bh);
 264         }
 265 }
 266
 267 /*
 268  * BIO operations
 269  */
 270 static void nilfs_end_bio_write(struct bio *bio, int err)
 271 {
 272         const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
 273         struct nilfs_write_info *wi = bio->bi_private;
 274
 275         if (err == -EOPNOTSUPP) {
 276                 set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
 277                 bio_put(bio);
 278                 /* to be detected by submit_seg_bio() */
 279         }
 280
 281         if (!uptodate)
 282                 atomic_inc(&wi->err);
 283
 284         bio_put(bio);
 285         complete(&wi->bio_event);
 286 }
 287
 288 static int nilfs_submit_seg_bio(struct nilfs_write_info *wi, int mode)
 289 {
 290         struct bio *bio = wi->bio;
 291         int err;
 292
 293         if (wi->nbio > 0 && bdi_write_congested(wi->bdi)) {
 294                 wait_for_completion(&wi->bio_event);
 295                 wi->nbio--;
 296                 if (unlikely(atomic_read(&wi->err))) {
 297                         bio_put(bio);
 298                         err = -EIO;
 299                         goto failed;
 300                 }
 301         }
 302
 303         bio->bi_end_io = nilfs_end_bio_write;
 304         bio->bi_private = wi;
 305         bio_get(bio);
 306         submit_bio(mode, bio);
 307         if (bio_flagged(bio, BIO_EOPNOTSUPP)) {
 308                 bio_put(bio);
 309                 err = -EOPNOTSUPP;
 310                 goto failed;
 311         }
 312         wi->nbio++;
 313         bio_put(bio);
 314
 315         wi->bio = NULL;
 316         wi->rest_blocks -= wi->end - wi->start;
 317         wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
 318         wi->start = wi->end;
 319         return 0;
 320
 321  failed:
 322         wi->bio = NULL;
 323         return err;
 324 }
 325
 326 /**
 327  * nilfs_alloc_seg_bio - allocate a bio for writing segment.
 328  * @sb: super block
 329  * @start: beginning disk block number of this BIO.
 330  * @nr_vecs: request size of page vector.
 331  *
 332  * alloc_seg_bio() allocates a new BIO structure and initialize it.
 333  *
 334  * Return Value: On success, pointer to the struct bio is returned.
 335  * On error, NULL is returned.
 336  */
 337 static struct bio *nilfs_alloc_seg_bio(struct super_block *sb, sector_t start,
 338                                        int nr_vecs)
 339 {
 340         struct bio *bio;
 341
 342         bio = bio_alloc(GFP_NOWAIT, nr_vecs);
 343         if (bio == NULL) {
 344                 while (!bio && (nr_vecs >>= 1))
 345                         bio = bio_alloc(GFP_NOWAIT, nr_vecs);
 346         }
 347         if (likely(bio)) {
 348                 bio->bi_bdev = sb->s_bdev;
 349                 bio->bi_sector = (sector_t)start << (sb->s_blocksize_bits - 9);
 350         }
 351         return bio;
 352 }
 353
 354 void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *segbuf,
 355                                 struct nilfs_write_info *wi)
 356 {
 357         wi->bio = NULL;
 358         wi->rest_blocks = segbuf->sb_sum.nblocks;
 359         wi->max_pages = bio_get_nr_vecs(wi->sb->s_bdev);
 360         wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
 361         wi->start = wi->end = 0;
 362         wi->nbio = 0;
 363         wi->blocknr = segbuf->sb_pseg_start;
 364
 365         atomic_set(&wi->err, 0);
 366         init_completion(&wi->bio_event);
 367 }
 368
 369 static int nilfs_submit_bh(struct nilfs_write_info *wi, struct buffer_head *bh,
 370                            int mode)
 371 {
 372         int len, err;
 373
 374         BUG_ON(wi->nr_vecs <= 0);
 375  repeat:
 376         if (!wi->bio) {
 377                 wi->bio = nilfs_alloc_seg_bio(wi->sb, wi->blocknr + wi->end,
 378                                               wi->nr_vecs);
 379                 if (unlikely(!wi->bio))
 380                         return -ENOMEM;
 381         }
 382
 383         len = bio_add_page(wi->bio, bh->b_page, bh->b_size, bh_offset(bh));
 384         if (len == bh->b_size) {
 385                 wi->end++;
 386                 return 0;
 387         }
 388         /* bio is FULL */
 389         err = nilfs_submit_seg_bio(wi, mode);
 390         /* never submit current bh */
 391         if (likely(!err))
 392                 goto repeat;
 393         return err;
 394 }
 395
 396 int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
 397                        struct nilfs_write_info *wi)
 398 {
 399         struct buffer_head *bh;
 400         int res, rw = WRITE;
 401
 402         list_for_each_entry(bh, &segbuf->sb_segsum_buffers, b_assoc_buffers) {
 403                 res = nilfs_submit_bh(wi, bh, rw);
 404                 if (unlikely(res))
 405                         goto failed_bio;
 406         }
 407
 408         list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
 409                 res = nilfs_submit_bh(wi, bh, rw);
 410                 if (unlikely(res))
 411                         goto failed_bio;
 412         }
 413
 414         if (wi->bio) {
 415                 /*
 416                  * Last BIO is always sent through the following
 417                  * submission.
 418                  */
 419                 rw |= (1 << BIO_RW_SYNCIO);
 420                 res = nilfs_submit_seg_bio(wi, rw);
 421                 if (unlikely(res))
 422                         goto failed_bio;
 423         }
 424
 425         res = 0;
 426  out:
 427         return res;
 428
 429  failed_bio:
 430         atomic_inc(&wi->err);
 431         goto out;
 432 }
 433
 434 /**
 435  * nilfs_segbuf_wait - wait for completion of requested BIOs
 436  * @wi: nilfs_write_info
 437  *
 438  * Return Value: On Success, 0 is returned. On Error, one of the following
 439  * negative error code is returned.
 440  *
 441  * %-EIO - I/O error
 442  */
 443 int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf,
 444                       struct nilfs_write_info *wi)
 445 {
 446         int err = 0;
 447
 448         if (!wi->nbio)
 449                 return 0;
 450
 451         do {
 452                 wait_for_completion(&wi->bio_event);
 453         } while (--wi->nbio > 0);
 454
 455         if (unlikely(atomic_read(&wi->err) > 0)) {
 456                 printk(KERN_ERR "NILFS: IO error writing segment\n");
 457                 err = -EIO;
 458                 segbuf->sb_io_error = 1;
 459         }
 460         return err;
 461 }