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         nilfs_segbuf_add_segsum_buffer(segbuf, bh);
 114         return 0;
 115 }
 116
 117 int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *segbuf,
 118                                 struct buffer_head **bhp)
 119 {
 120         struct buffer_head *bh;
 121
 122         bh = sb_getblk(segbuf->sb_super,
 123                        segbuf->sb_pseg_start + segbuf->sb_sum.nblocks);
 124         if (unlikely(!bh))
 125                 return -ENOMEM;
 126
 127         nilfs_segbuf_add_payload_buffer(segbuf, bh);
 128         *bhp = bh;
 129         return 0;
 130 }
 131
 132 int nilfs_segbuf_reset(struct nilfs_segment_buffer *segbuf, unsigned int flags,
 133                        time_t ctime, __u64 cno)
 134 {
 135         int err;
 136
 137         segbuf->sb_sum.nblocks = segbuf->sb_sum.nsumblk = 0;
 138         err = nilfs_segbuf_extend_segsum(segbuf);
 139         if (unlikely(err))
 140                 return err;
 141
 142         segbuf->sb_sum.flags = flags;
 143         segbuf->sb_sum.sumbytes = sizeof(struct nilfs_segment_summary);
 144         segbuf->sb_sum.nfinfo = segbuf->sb_sum.nfileblk = 0;
 145         segbuf->sb_sum.ctime = ctime;
 146         segbuf->sb_sum.cno = cno;
 147         return 0;
 148 }
 149
 150 /*
 151  * Setup segment summary
 152  */
 153 void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *segbuf)
 154 {
 155         struct nilfs_segment_summary *raw_sum;
 156         struct buffer_head *bh_sum;
 157
 158         bh_sum = list_entry(segbuf->sb_segsum_buffers.next,
 159                             struct buffer_head, b_assoc_buffers);
 160         raw_sum = (struct nilfs_segment_summary *)bh_sum->b_data;
 161
 162         raw_sum->ss_magic    = cpu_to_le32(NILFS_SEGSUM_MAGIC);
 163         raw_sum->ss_bytes    = cpu_to_le16(sizeof(*raw_sum));
 164         raw_sum->ss_flags    = cpu_to_le16(segbuf->sb_sum.flags);
 165         raw_sum->ss_seq      = cpu_to_le64(segbuf->sb_sum.seg_seq);
 166         raw_sum->ss_create   = cpu_to_le64(segbuf->sb_sum.ctime);
 167         raw_sum->ss_next     = cpu_to_le64(segbuf->sb_sum.next);
 168         raw_sum->ss_nblocks  = cpu_to_le32(segbuf->sb_sum.nblocks);
 169         raw_sum->ss_nfinfo   = cpu_to_le32(segbuf->sb_sum.nfinfo);
 170         raw_sum->ss_sumbytes = cpu_to_le32(segbuf->sb_sum.sumbytes);
 171         raw_sum->ss_pad      = 0;
 172         raw_sum->ss_cno      = cpu_to_le64(segbuf->sb_sum.cno);
 173 }
 174
 175 /*
 176  * CRC calculation routines
 177  */
 178 static void
 179 nilfs_segbuf_fill_in_segsum_crc(struct nilfs_segment_buffer *segbuf, u32 seed)
 180 {
 181         struct buffer_head *bh;
 182         struct nilfs_segment_summary *raw_sum;
 183         unsigned long size, bytes = segbuf->sb_sum.sumbytes;
 184         u32 crc;
 185
 186         bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
 187                         b_assoc_buffers);
 188
 189         raw_sum = (struct nilfs_segment_summary *)bh->b_data;
 190         size = min_t(unsigned long, bytes, bh->b_size);
 191         crc = crc32_le(seed,
 192                        (unsigned char *)raw_sum +
 193                        sizeof(raw_sum->ss_datasum) + sizeof(raw_sum->ss_sumsum),
 194                        size - (sizeof(raw_sum->ss_datasum) +
 195                                sizeof(raw_sum->ss_sumsum)));
 196
 197         list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
 198                                      b_assoc_buffers) {
 199                 bytes -= size;
 200                 size = min_t(unsigned long, bytes, bh->b_size);
 201                 crc = crc32_le(crc, bh->b_data, size);
 202         }
 203         raw_sum->ss_sumsum = cpu_to_le32(crc);
 204 }
 205
 206 static void nilfs_segbuf_fill_in_data_crc(struct nilfs_segment_buffer *segbuf,
 207                                           u32 seed)
 208 {
 209         struct buffer_head *bh;
 210         struct nilfs_segment_summary *raw_sum;
 211         void *kaddr;
 212         u32 crc;
 213
 214         bh = list_entry(segbuf->sb_segsum_buffers.next, struct buffer_head,
 215                         b_assoc_buffers);
 216         raw_sum = (struct nilfs_segment_summary *)bh->b_data;
 217         crc = crc32_le(seed,
 218                        (unsigned char *)raw_sum + sizeof(raw_sum->ss_datasum),
 219                        bh->b_size - sizeof(raw_sum->ss_datasum));
 220
 221         list_for_each_entry_continue(bh, &segbuf->sb_segsum_buffers,
 222                                      b_assoc_buffers) {
 223                 crc = crc32_le(crc, bh->b_data, bh->b_size);
 224         }
 225         list_for_each_entry(bh, &segbuf->sb_payload_buffers, b_assoc_buffers) {
 226                 kaddr = kmap_atomic(bh->b_page);
 227                 crc = crc32_le(crc, kaddr + bh_offset(bh), bh->b_size);
 228                 kunmap_atomic(kaddr);
 229         }
 230         raw_sum->ss_datasum = cpu_to_le32(crc);
 231 }
 232
 233 static void
 234 nilfs_segbuf_fill_in_super_root_crc(struct nilfs_segment_buffer *segbuf,
 235                                     u32 seed)
 236 {
 237         struct nilfs_super_root *raw_sr;
 238         struct the_nilfs *nilfs = segbuf->sb_super->s_fs_info;
 239         unsigned int srsize;
 240         u32 crc;
 241
 242         raw_sr = (struct nilfs_super_root *)segbuf->sb_super_root->b_data;
 243         srsize = NILFS_SR_BYTES(nilfs->ns_inode_size);
 244         crc = crc32_le(seed,
 245                        (unsigned char *)raw_sr + sizeof(raw_sr->sr_sum),
 246                        srsize - sizeof(raw_sr->sr_sum));
 247         raw_sr->sr_sum = cpu_to_le32(crc);
 248 }
 249
 250 static void nilfs_release_buffers(struct list_head *list)
 251 {
 252         struct buffer_head *bh, *n;
 253
 254         list_for_each_entry_safe(bh, n, list, b_assoc_buffers) {
 255                 list_del_init(&bh->b_assoc_buffers);
 256                 brelse(bh);
 257         }
 258 }
 259
 260 static void nilfs_segbuf_clear(struct nilfs_segment_buffer *segbuf)
 261 {
 262         nilfs_release_buffers(&segbuf->sb_segsum_buffers);
 263         nilfs_release_buffers(&segbuf->sb_payload_buffers);
 264         segbuf->sb_super_root = NULL;
 265 }
 266
 267 /*
 268  * Iterators for segment buffers
 269  */
 270 void nilfs_clear_logs(struct list_head *logs)
 271 {
 272         struct nilfs_segment_buffer *segbuf;
 273
 274         list_for_each_entry(segbuf, logs, sb_list)
 275                 nilfs_segbuf_clear(segbuf);
 276 }
 277
 278 void nilfs_truncate_logs(struct list_head *logs,
 279                          struct nilfs_segment_buffer *last)
 280 {
 281         struct nilfs_segment_buffer *n, *segbuf;
 282
 283         segbuf = list_prepare_entry(last, logs, sb_list);
 284         list_for_each_entry_safe_continue(segbuf, n, logs, sb_list) {
 285                 list_del_init(&segbuf->sb_list);
 286                 nilfs_segbuf_clear(segbuf);
 287                 nilfs_segbuf_free(segbuf);
 288         }
 289 }
 290
 291 int nilfs_write_logs(struct list_head *logs, struct the_nilfs *nilfs)
 292 {
 293         struct nilfs_segment_buffer *segbuf;
 294         int ret = 0;
 295
 296         list_for_each_entry(segbuf, logs, sb_list) {
 297                 ret = nilfs_segbuf_write(segbuf, nilfs);
 298                 if (ret)
 299                         break;
 300         }
 301         return ret;
 302 }
 303
 304 int nilfs_wait_on_logs(struct list_head *logs)
 305 {
 306         struct nilfs_segment_buffer *segbuf;
 307         int err, ret = 0;
 308
 309         list_for_each_entry(segbuf, logs, sb_list) {
 310                 err = nilfs_segbuf_wait(segbuf);
 311                 if (err && !ret)
 312                         ret = err;
 313         }
 314         return ret;
 315 }
 316
 317 /**
 318  * nilfs_add_checksums_on_logs - add checksums on the logs
 319  * @logs: list of segment buffers storing target logs
 320  * @seed: checksum seed value
 321  */
 322 void nilfs_add_checksums_on_logs(struct list_head *logs, u32 seed)
 323 {
 324         struct nilfs_segment_buffer *segbuf;
 325
 326         list_for_each_entry(segbuf, logs, sb_list) {
 327                 if (segbuf->sb_super_root)
 328                         nilfs_segbuf_fill_in_super_root_crc(segbuf, seed);
 329                 nilfs_segbuf_fill_in_segsum_crc(segbuf, seed);
 330                 nilfs_segbuf_fill_in_data_crc(segbuf, seed);
 331         }
 332 }
 333
 334 /*
 335  * BIO operations
 336  */
 337 static void nilfs_end_bio_write(struct bio *bio)
 338 {
 339         struct nilfs_segment_buffer *segbuf = bio->bi_private;
 340
 341         if (bio->bi_error)
 342                 atomic_inc(&segbuf->sb_err);
 343
 344         bio_put(bio);
 345         complete(&segbuf->sb_bio_event);
 346 }
 347
 348 static int nilfs_segbuf_submit_bio(struct nilfs_segment_buffer *segbuf,
 349                                    struct nilfs_write_info *wi, int mode,
 350                                    int mode_flags)
 351 {
 352         struct bio *bio = wi->bio;
 353         int err;
 354
 355         if (segbuf->sb_nbio > 0 &&
 356             bdi_write_congested(segbuf->sb_super->s_bdi)) {
 357                 wait_for_completion(&segbuf->sb_bio_event);
 358                 segbuf->sb_nbio--;
 359                 if (unlikely(atomic_read(&segbuf->sb_err))) {
 360                         bio_put(bio);
 361                         err = -EIO;
 362                         goto failed;
 363                 }
 364         }
 365
 366         bio->bi_end_io = nilfs_end_bio_write;
 367         bio->bi_private = segbuf;
 368         bio_set_op_attrs(bio, mode, mode_flags);
 369         submit_bio(bio);
 370         segbuf->sb_nbio++;
 371
 372         wi->bio = NULL;
 373         wi->rest_blocks -= wi->end - wi->start;
 374         wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
 375         wi->start = wi->end;
 376         return 0;
 377
 378  failed:
 379         wi->bio = NULL;
 380         return err;
 381 }
 382
 383 /**
 384  * nilfs_alloc_seg_bio - allocate a new bio for writing log
 385  * @nilfs: nilfs object
 386  * @start: start block number of the bio
 387  * @nr_vecs: request size of page vector.
 388  *
 389  * Return Value: On success, pointer to the struct bio is returned.
 390  * On error, NULL is returned.
 391  */
 392 static struct bio *nilfs_alloc_seg_bio(struct the_nilfs *nilfs, sector_t start,
 393                                        int nr_vecs)
 394 {
 395         struct bio *bio;
 396
 397         bio = bio_alloc(GFP_NOIO, nr_vecs);
 398         if (bio == NULL) {
 399                 while (!bio && (nr_vecs >>= 1))
 400                         bio = bio_alloc(GFP_NOIO, nr_vecs);
 401         }
 402         if (likely(bio)) {
 403                 bio->bi_bdev = nilfs->ns_bdev;
 404                 bio->bi_iter.bi_sector =
 405                         start << (nilfs->ns_blocksize_bits - 9);
 406         }
 407         return bio;
 408 }
 409
 410 static void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *segbuf,
 411                                        struct nilfs_write_info *wi)
 412 {
 413         wi->bio = NULL;
 414         wi->rest_blocks = segbuf->sb_sum.nblocks;
 415         wi->max_pages = BIO_MAX_PAGES;
 416         wi->nr_vecs = min(wi->max_pages, wi->rest_blocks);
 417         wi->start = wi->end = 0;
 418         wi->blocknr = segbuf->sb_pseg_start;
 419 }
 420
 421 static int nilfs_segbuf_submit_bh(struct nilfs_segment_buffer *segbuf,
 422                                   struct nilfs_write_info *wi,
 423                                   struct buffer_head *bh, int mode)
 424 {
 425         int len, err;
 426
 427         BUG_ON(wi->nr_vecs <= 0);
 428  repeat:
 429         if (!wi->bio) {
 430                 wi->bio = nilfs_alloc_seg_bio(wi->nilfs, wi->blocknr + wi->end,
 431                                               wi->nr_vecs);
 432                 if (unlikely(!wi->bio))
 433                         return -ENOMEM;
 434         }
 435
 436         len = bio_add_page(wi->bio, bh->b_page, bh->b_size, bh_offset(bh));
 437         if (len == bh->b_size) {
 438                 wi->end++;
 439                 return 0;
 440         }
 441         /* bio is FULL */
 442         err = nilfs_segbuf_submit_bio(segbuf, wi, mode, 0);
 443         /* never submit current bh */
 444         if (likely(!err))
 445                 goto repeat;
 446         return err;
 447 }
 448
 449 /**
 450  * nilfs_segbuf_write - submit write requests of a log
 451  * @segbuf: buffer storing a log to be written
 452  * @nilfs: nilfs object
 453  *
 454  * Return Value: On Success, 0 is returned. On Error, one of the following
 455  * negative error code is returned.
 456  *
 457  * %-EIO - I/O error
 458  *
 459  * %-ENOMEM - Insufficient memory available.
 460  */
 461 static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
 462                               struct the_nilfs *nilfs)
 463 {
 464         struct nilfs_write_info wi;
 465         struct buffer_head *bh;
 466         int res = 0;
 467
 468         wi.nilfs = nilfs;
 469         nilfs_segbuf_prepare_write(segbuf, &wi);
 470
 471         list_for_each_entry(bh, &segbuf->sb_segsum_buffers, b_assoc_buffers) {
 472                 res = nilfs_segbuf_submit_bh(segbuf, &wi, bh, REQ_OP_WRITE);
 473                 if (unlikely(res))
 474                         goto failed_bio;
 475         }
 476
 477         list_for_each_entry(bh, &segbuf->sb_payload_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         if (wi.bio) {
 484                 /*
 485                  * Last BIO is always sent through the following
 486                  * submission.
 487                  */
 488                 res = nilfs_segbuf_submit_bio(segbuf, &wi, REQ_OP_WRITE,
 489                                               REQ_SYNC);
 490         }
 491
 492  failed_bio:
 493         return res;
 494 }
 495
 496 /**
 497  * nilfs_segbuf_wait - wait for completion of requested BIOs
 498  * @segbuf: segment buffer
 499  *
 500  * Return Value: On Success, 0 is returned. On Error, one of the following
 501  * negative error code is returned.
 502  *
 503  * %-EIO - I/O error
 504  */
 505 static int nilfs_segbuf_wait(struct nilfs_segment_buffer *segbuf)
 506 {
 507         int err = 0;
 508
 509         if (!segbuf->sb_nbio)
 510                 return 0;
 511
 512         do {
 513                 wait_for_completion(&segbuf->sb_bio_event);
 514         } while (--segbuf->sb_nbio > 0);
 515
 516         if (unlikely(atomic_read(&segbuf->sb_err) > 0)) {
 517                 printk(KERN_ERR "NILFS: IO error writing segment\n");
 518                 err = -EIO;
 519         }
 520         return err;
 521 }