SAFE public projects git trees. - safe/jmp/linux-2.6/blob - fs/nilfs2/sufile.c

   1 /*
   2  * sufile.c - NILFS segment usage file.
   3  *
   4  * Copyright (C) 2006-2008 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 Koji Sato <koji@osrg.net>.
  21  * Rivised by Ryusuke Konishi <ryusuke@osrg.net>.
  22  */
  23
  24 #include <linux/kernel.h>
  25 #include <linux/fs.h>
  26 #include <linux/string.h>
  27 #include <linux/buffer_head.h>
  28 #include <linux/errno.h>
  29 #include <linux/nilfs2_fs.h>
  30 #include "mdt.h"
  31 #include "sufile.h"
  32
  33
  34 struct nilfs_sufile_info {
  35         struct nilfs_mdt_info mi;
  36         unsigned long ncleansegs;
  37 };
  38
  39 static inline struct nilfs_sufile_info *NILFS_SUI(struct inode *sufile)
  40 {
  41         return (struct nilfs_sufile_info *)NILFS_MDT(sufile);
  42 }
  43
  44 static inline unsigned long
  45 nilfs_sufile_segment_usages_per_block(const struct inode *sufile)
  46 {
  47         return NILFS_MDT(sufile)->mi_entries_per_block;
  48 }
  49
  50 static unsigned long
  51 nilfs_sufile_get_blkoff(const struct inode *sufile, __u64 segnum)
  52 {
  53         __u64 t = segnum + NILFS_MDT(sufile)->mi_first_entry_offset;
  54         do_div(t, nilfs_sufile_segment_usages_per_block(sufile));
  55         return (unsigned long)t;
  56 }
  57
  58 static unsigned long
  59 nilfs_sufile_get_offset(const struct inode *sufile, __u64 segnum)
  60 {
  61         __u64 t = segnum + NILFS_MDT(sufile)->mi_first_entry_offset;
  62         return do_div(t, nilfs_sufile_segment_usages_per_block(sufile));
  63 }
  64
  65 static unsigned long
  66 nilfs_sufile_segment_usages_in_block(const struct inode *sufile, __u64 curr,
  67                                      __u64 max)
  68 {
  69         return min_t(unsigned long,
  70                      nilfs_sufile_segment_usages_per_block(sufile) -
  71                      nilfs_sufile_get_offset(sufile, curr),
  72                      max - curr + 1);
  73 }
  74
  75 static struct nilfs_segment_usage *
  76 nilfs_sufile_block_get_segment_usage(const struct inode *sufile, __u64 segnum,
  77                                      struct buffer_head *bh, void *kaddr)
  78 {
  79         return kaddr + bh_offset(bh) +
  80                 nilfs_sufile_get_offset(sufile, segnum) *
  81                 NILFS_MDT(sufile)->mi_entry_size;
  82 }
  83
  84 static inline int nilfs_sufile_get_header_block(struct inode *sufile,
  85                                                 struct buffer_head **bhp)
  86 {
  87         return nilfs_mdt_get_block(sufile, 0, 0, NULL, bhp);
  88 }
  89
  90 static inline int
  91 nilfs_sufile_get_segment_usage_block(struct inode *sufile, __u64 segnum,
  92                                      int create, struct buffer_head **bhp)
  93 {
  94         return nilfs_mdt_get_block(sufile,
  95                                    nilfs_sufile_get_blkoff(sufile, segnum),
  96                                    create, NULL, bhp);
  97 }
  98
  99 static void nilfs_sufile_mod_counter(struct buffer_head *header_bh,
 100                                      u64 ncleanadd, u64 ndirtyadd)
 101 {
 102         struct nilfs_sufile_header *header;
 103         void *kaddr;
 104
 105         kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
 106         header = kaddr + bh_offset(header_bh);
 107         le64_add_cpu(&header->sh_ncleansegs, ncleanadd);
 108         le64_add_cpu(&header->sh_ndirtysegs, ndirtyadd);
 109         kunmap_atomic(kaddr, KM_USER0);
 110
 111         nilfs_mdt_mark_buffer_dirty(header_bh);
 112 }
 113
 114 /**
 115  * nilfs_sufile_get_ncleansegs - return the number of clean segments
 116  * @sufile: inode of segment usage file
 117  */
 118 unsigned long nilfs_sufile_get_ncleansegs(struct inode *sufile)
 119 {
 120         return NILFS_SUI(sufile)->ncleansegs;
 121 }
 122
 123 /**
 124  * nilfs_sufile_updatev - modify multiple segment usages at a time
 125  * @sufile: inode of segment usage file
 126  * @segnumv: array of segment numbers
 127  * @nsegs: size of @segnumv array
 128  * @create: creation flag
 129  * @ndone: place to store number of modified segments on @segnumv
 130  * @dofunc: primitive operation for the update
 131  *
 132  * Description: nilfs_sufile_updatev() repeatedly calls @dofunc
 133  * against the given array of segments.  The @dofunc is called with
 134  * buffers of a header block and the sufile block in which the target
 135  * segment usage entry is contained.  If @ndone is given, the number
 136  * of successfully modified segments from the head is stored in the
 137  * place @ndone points to.
 138  *
 139  * Return Value: On success, zero is returned.  On error, one of the
 140  * following negative error codes is returned.
 141  *
 142  * %-EIO - I/O error.
 143  *
 144  * %-ENOMEM - Insufficient amount of memory available.
 145  *
 146  * %-ENOENT - Given segment usage is in hole block (may be returned if
 147  *            @create is zero)
 148  *
 149  * %-EINVAL - Invalid segment usage number
 150  */
 151 int nilfs_sufile_updatev(struct inode *sufile, __u64 *segnumv, size_t nsegs,
 152                          int create, size_t *ndone,
 153                          void (*dofunc)(struct inode *, __u64,
 154                                         struct buffer_head *,
 155                                         struct buffer_head *))
 156 {
 157         struct buffer_head *header_bh, *bh;
 158         unsigned long blkoff, prev_blkoff;
 159         __u64 *seg;
 160         size_t nerr = 0, n = 0;
 161         int ret = 0;
 162
 163         if (unlikely(nsegs == 0))
 164                 goto out;
 165
 166         down_write(&NILFS_MDT(sufile)->mi_sem);
 167         for (seg = segnumv; seg < segnumv + nsegs; seg++) {
 168                 if (unlikely(*seg >= nilfs_sufile_get_nsegments(sufile))) {
 169                         printk(KERN_WARNING
 170                                "%s: invalid segment number: %llu\n", __func__,
 171                                (unsigned long long)*seg);
 172                         nerr++;
 173                 }
 174         }
 175         if (nerr > 0) {
 176                 ret = -EINVAL;
 177                 goto out_sem;
 178         }
 179
 180         ret = nilfs_sufile_get_header_block(sufile, &header_bh);
 181         if (ret < 0)
 182                 goto out_sem;
 183
 184         seg = segnumv;
 185         blkoff = nilfs_sufile_get_blkoff(sufile, *seg);
 186         ret = nilfs_mdt_get_block(sufile, blkoff, create, NULL, &bh);
 187         if (ret < 0)
 188                 goto out_header;
 189
 190         for (;;) {
 191                 dofunc(sufile, *seg, header_bh, bh);
 192
 193                 if (++seg >= segnumv + nsegs)
 194                         break;
 195                 prev_blkoff = blkoff;
 196                 blkoff = nilfs_sufile_get_blkoff(sufile, *seg);
 197                 if (blkoff == prev_blkoff)
 198                         continue;
 199
 200                 /* get different block */
 201                 brelse(bh);
 202                 ret = nilfs_mdt_get_block(sufile, blkoff, create, NULL, &bh);
 203                 if (unlikely(ret < 0))
 204                         goto out_header;
 205         }
 206         brelse(bh);
 207
 208  out_header:
 209         n = seg - segnumv;
 210         brelse(header_bh);
 211  out_sem:
 212         up_write(&NILFS_MDT(sufile)->mi_sem);
 213  out:
 214         if (ndone)
 215                 *ndone = n;
 216         return ret;
 217 }
 218
 219 int nilfs_sufile_update(struct inode *sufile, __u64 segnum, int create,
 220                         void (*dofunc)(struct inode *, __u64,
 221                                        struct buffer_head *,
 222                                        struct buffer_head *))
 223 {
 224         struct buffer_head *header_bh, *bh;
 225         int ret;
 226
 227         if (unlikely(segnum >= nilfs_sufile_get_nsegments(sufile))) {
 228                 printk(KERN_WARNING "%s: invalid segment number: %llu\n",
 229                        __func__, (unsigned long long)segnum);
 230                 return -EINVAL;
 231         }
 232         down_write(&NILFS_MDT(sufile)->mi_sem);
 233
 234         ret = nilfs_sufile_get_header_block(sufile, &header_bh);
 235         if (ret < 0)
 236                 goto out_sem;
 237
 238         ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, create, &bh);
 239         if (!ret) {
 240                 dofunc(sufile, segnum, header_bh, bh);
 241                 brelse(bh);
 242         }
 243         brelse(header_bh);
 244
 245  out_sem:
 246         up_write(&NILFS_MDT(sufile)->mi_sem);
 247         return ret;
 248 }
 249
 250 /**
 251  * nilfs_sufile_alloc - allocate a segment
 252  * @sufile: inode of segment usage file
 253  * @segnump: pointer to segment number
 254  *
 255  * Description: nilfs_sufile_alloc() allocates a clean segment.
 256  *
 257  * Return Value: On success, 0 is returned and the segment number of the
 258  * allocated segment is stored in the place pointed by @segnump. On error, one
 259  * of the following negative error codes is returned.
 260  *
 261  * %-EIO - I/O error.
 262  *
 263  * %-ENOMEM - Insufficient amount of memory available.
 264  *
 265  * %-ENOSPC - No clean segment left.
 266  */
 267 int nilfs_sufile_alloc(struct inode *sufile, __u64 *segnump)
 268 {
 269         struct buffer_head *header_bh, *su_bh;
 270         struct nilfs_sufile_header *header;
 271         struct nilfs_segment_usage *su;
 272         size_t susz = NILFS_MDT(sufile)->mi_entry_size;
 273         __u64 segnum, maxsegnum, last_alloc;
 274         void *kaddr;
 275         unsigned long nsegments, ncleansegs, nsus;
 276         int ret, i, j;
 277
 278         down_write(&NILFS_MDT(sufile)->mi_sem);
 279
 280         ret = nilfs_sufile_get_header_block(sufile, &header_bh);
 281         if (ret < 0)
 282                 goto out_sem;
 283         kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
 284         header = kaddr + bh_offset(header_bh);
 285         ncleansegs = le64_to_cpu(header->sh_ncleansegs);
 286         last_alloc = le64_to_cpu(header->sh_last_alloc);
 287         kunmap_atomic(kaddr, KM_USER0);
 288
 289         nsegments = nilfs_sufile_get_nsegments(sufile);
 290         segnum = last_alloc + 1;
 291         maxsegnum = nsegments - 1;
 292         for (i = 0; i < nsegments; i += nsus) {
 293                 if (segnum >= nsegments) {
 294                         /* wrap around */
 295                         segnum = 0;
 296                         maxsegnum = last_alloc;
 297                 }
 298                 ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 1,
 299                                                            &su_bh);
 300                 if (ret < 0)
 301                         goto out_header;
 302                 kaddr = kmap_atomic(su_bh->b_page, KM_USER0);
 303                 su = nilfs_sufile_block_get_segment_usage(
 304                         sufile, segnum, su_bh, kaddr);
 305
 306                 nsus = nilfs_sufile_segment_usages_in_block(
 307                         sufile, segnum, maxsegnum);
 308                 for (j = 0; j < nsus; j++, su = (void *)su + susz, segnum++) {
 309                         if (!nilfs_segment_usage_clean(su))
 310                                 continue;
 311                         /* found a clean segment */
 312                         nilfs_segment_usage_set_dirty(su);
 313                         kunmap_atomic(kaddr, KM_USER0);
 314
 315                         kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
 316                         header = kaddr + bh_offset(header_bh);
 317                         le64_add_cpu(&header->sh_ncleansegs, -1);
 318                         le64_add_cpu(&header->sh_ndirtysegs, 1);
 319                         header->sh_last_alloc = cpu_to_le64(segnum);
 320                         kunmap_atomic(kaddr, KM_USER0);
 321
 322                         NILFS_SUI(sufile)->ncleansegs--;
 323                         nilfs_mdt_mark_buffer_dirty(header_bh);
 324                         nilfs_mdt_mark_buffer_dirty(su_bh);
 325                         nilfs_mdt_mark_dirty(sufile);
 326                         brelse(su_bh);
 327                         *segnump = segnum;
 328                         goto out_header;
 329                 }
 330
 331                 kunmap_atomic(kaddr, KM_USER0);
 332                 brelse(su_bh);
 333         }
 334
 335         /* no segments left */
 336         ret = -ENOSPC;
 337
 338  out_header:
 339         brelse(header_bh);
 340
 341  out_sem:
 342         up_write(&NILFS_MDT(sufile)->mi_sem);
 343         return ret;
 344 }
 345
 346 void nilfs_sufile_do_cancel_free(struct inode *sufile, __u64 segnum,
 347                                  struct buffer_head *header_bh,
 348                                  struct buffer_head *su_bh)
 349 {
 350         struct nilfs_segment_usage *su;
 351         void *kaddr;
 352
 353         kaddr = kmap_atomic(su_bh->b_page, KM_USER0);
 354         su = nilfs_sufile_block_get_segment_usage(sufile, segnum, su_bh, kaddr);
 355         if (unlikely(!nilfs_segment_usage_clean(su))) {
 356                 printk(KERN_WARNING "%s: segment %llu must be clean\n",
 357                        __func__, (unsigned long long)segnum);
 358                 kunmap_atomic(kaddr, KM_USER0);
 359                 return;
 360         }
 361         nilfs_segment_usage_set_dirty(su);
 362         kunmap_atomic(kaddr, KM_USER0);
 363
 364         nilfs_sufile_mod_counter(header_bh, -1, 1);
 365         NILFS_SUI(sufile)->ncleansegs--;
 366
 367         nilfs_mdt_mark_buffer_dirty(su_bh);
 368         nilfs_mdt_mark_dirty(sufile);
 369 }
 370
 371 void nilfs_sufile_do_scrap(struct inode *sufile, __u64 segnum,
 372                            struct buffer_head *header_bh,
 373                            struct buffer_head *su_bh)
 374 {
 375         struct nilfs_segment_usage *su;
 376         void *kaddr;
 377         int clean, dirty;
 378
 379         kaddr = kmap_atomic(su_bh->b_page, KM_USER0);
 380         su = nilfs_sufile_block_get_segment_usage(sufile, segnum, su_bh, kaddr);
 381         if (su->su_flags == cpu_to_le32(1UL << NILFS_SEGMENT_USAGE_DIRTY) &&
 382             su->su_nblocks == cpu_to_le32(0)) {
 383                 kunmap_atomic(kaddr, KM_USER0);
 384                 return;
 385         }
 386         clean = nilfs_segment_usage_clean(su);
 387         dirty = nilfs_segment_usage_dirty(su);
 388
 389         /* make the segment garbage */
 390         su->su_lastmod = cpu_to_le64(0);
 391         su->su_nblocks = cpu_to_le32(0);
 392         su->su_flags = cpu_to_le32(1UL << NILFS_SEGMENT_USAGE_DIRTY);
 393         kunmap_atomic(kaddr, KM_USER0);
 394
 395         nilfs_sufile_mod_counter(header_bh, clean ? (u64)-1 : 0, dirty ? 0 : 1);
 396         NILFS_SUI(sufile)->ncleansegs -= clean;
 397
 398         nilfs_mdt_mark_buffer_dirty(su_bh);
 399         nilfs_mdt_mark_dirty(sufile);
 400 }
 401
 402 void nilfs_sufile_do_free(struct inode *sufile, __u64 segnum,
 403                           struct buffer_head *header_bh,
 404                           struct buffer_head *su_bh)
 405 {
 406         struct nilfs_segment_usage *su;
 407         void *kaddr;
 408         int sudirty;
 409
 410         kaddr = kmap_atomic(su_bh->b_page, KM_USER0);
 411         su = nilfs_sufile_block_get_segment_usage(sufile, segnum, su_bh, kaddr);
 412         if (nilfs_segment_usage_clean(su)) {
 413                 printk(KERN_WARNING "%s: segment %llu is already clean\n",
 414                        __func__, (unsigned long long)segnum);
 415                 kunmap_atomic(kaddr, KM_USER0);
 416                 return;
 417         }
 418         WARN_ON(nilfs_segment_usage_error(su));
 419         WARN_ON(!nilfs_segment_usage_dirty(su));
 420
 421         sudirty = nilfs_segment_usage_dirty(su);
 422         nilfs_segment_usage_set_clean(su);
 423         kunmap_atomic(kaddr, KM_USER0);
 424         nilfs_mdt_mark_buffer_dirty(su_bh);
 425
 426         nilfs_sufile_mod_counter(header_bh, 1, sudirty ? (u64)-1 : 0);
 427         NILFS_SUI(sufile)->ncleansegs++;
 428
 429         nilfs_mdt_mark_dirty(sufile);
 430 }
 431
 432 /**
 433  * nilfs_sufile_get_segment_usage - get a segment usage
 434  * @sufile: inode of segment usage file
 435  * @segnum: segment number
 436  * @sup: pointer to segment usage
 437  * @bhp: pointer to buffer head
 438  *
 439  * Description: nilfs_sufile_get_segment_usage() acquires the segment usage
 440  * specified by @segnum.
 441  *
 442  * Return Value: On success, 0 is returned, and the segment usage and the
 443  * buffer head of the buffer on which the segment usage is located are stored
 444  * in the place pointed by @sup and @bhp, respectively. On error, one of the
 445  * following negative error codes is returned.
 446  *
 447  * %-EIO - I/O error.
 448  *
 449  * %-ENOMEM - Insufficient amount of memory available.
 450  *
 451  * %-EINVAL - Invalid segment usage number.
 452  */
 453 int nilfs_sufile_get_segment_usage(struct inode *sufile, __u64 segnum,
 454                                    struct nilfs_segment_usage **sup,
 455                                    struct buffer_head **bhp)
 456 {
 457         struct buffer_head *bh;
 458         struct nilfs_segment_usage *su;
 459         void *kaddr;
 460         int ret;
 461
 462         /* segnum is 0 origin */
 463         if (segnum >= nilfs_sufile_get_nsegments(sufile))
 464                 return -EINVAL;
 465         down_write(&NILFS_MDT(sufile)->mi_sem);
 466         ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 1, &bh);
 467         if (ret < 0)
 468                 goto out_sem;
 469         kaddr = kmap(bh->b_page);
 470         su = nilfs_sufile_block_get_segment_usage(sufile, segnum, bh, kaddr);
 471         if (nilfs_segment_usage_error(su)) {
 472                 kunmap(bh->b_page);
 473                 brelse(bh);
 474                 ret = -EINVAL;
 475                 goto out_sem;
 476         }
 477
 478         if (sup != NULL)
 479                 *sup = su;
 480         *bhp = bh;
 481
 482  out_sem:
 483         up_write(&NILFS_MDT(sufile)->mi_sem);
 484         return ret;
 485 }
 486
 487 /**
 488  * nilfs_sufile_put_segment_usage - put a segment usage
 489  * @sufile: inode of segment usage file
 490  * @segnum: segment number
 491  * @bh: buffer head
 492  *
 493  * Description: nilfs_sufile_put_segment_usage() releases the segment usage
 494  * specified by @segnum. @bh must be the buffer head which have been returned
 495  * by a previous call to nilfs_sufile_get_segment_usage() with @segnum.
 496  */
 497 void nilfs_sufile_put_segment_usage(struct inode *sufile, __u64 segnum,
 498                                     struct buffer_head *bh)
 499 {
 500         kunmap(bh->b_page);
 501         brelse(bh);
 502 }
 503
 504 /**
 505  * nilfs_sufile_mark_dirty - mark the buffer having a segment usage dirty
 506  * @sufile: inode of segment usage file
 507  * @segnum: segment number
 508  */
 509 int nilfs_sufile_mark_dirty(struct inode *sufile, __u64 segnum)
 510 {
 511         struct buffer_head *bh;
 512         int ret;
 513
 514         ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 0, &bh);
 515         if (!ret) {
 516                 nilfs_mdt_mark_buffer_dirty(bh);
 517                 nilfs_mdt_mark_dirty(sufile);
 518                 brelse(bh);
 519         }
 520         return ret;
 521 }
 522
 523 /**
 524  * nilfs_sufile_set_segment_usage - set usage of a segment
 525  * @sufile: inode of segment usage file
 526  * @segnum: segment number
 527  * @nblocks: number of live blocks in the segment
 528  * @modtime: modification time (option)
 529  */
 530 int nilfs_sufile_set_segment_usage(struct inode *sufile, __u64 segnum,
 531                                    unsigned long nblocks, time_t modtime)
 532 {
 533         struct buffer_head *bh;
 534         struct nilfs_segment_usage *su;
 535         void *kaddr;
 536         int ret;
 537
 538         down_write(&NILFS_MDT(sufile)->mi_sem);
 539         ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 0, &bh);
 540         if (ret < 0)
 541                 goto out_sem;
 542
 543         kaddr = kmap_atomic(bh->b_page, KM_USER0);
 544         su = nilfs_sufile_block_get_segment_usage(sufile, segnum, bh, kaddr);
 545         WARN_ON(nilfs_segment_usage_error(su));
 546         if (modtime)
 547                 su->su_lastmod = cpu_to_le64(modtime);
 548         su->su_nblocks = cpu_to_le32(nblocks);
 549         kunmap_atomic(kaddr, KM_USER0);
 550
 551         nilfs_mdt_mark_buffer_dirty(bh);
 552         nilfs_mdt_mark_dirty(sufile);
 553         brelse(bh);
 554
 555  out_sem:
 556         up_write(&NILFS_MDT(sufile)->mi_sem);
 557         return ret;
 558 }
 559
 560 /**
 561  * nilfs_sufile_get_stat - get segment usage statistics
 562  * @sufile: inode of segment usage file
 563  * @stat: pointer to a structure of segment usage statistics
 564  *
 565  * Description: nilfs_sufile_get_stat() returns information about segment
 566  * usage.
 567  *
 568  * Return Value: On success, 0 is returned, and segment usage information is
 569  * stored in the place pointed by @stat. On error, one of the following
 570  * negative error codes is returned.
 571  *
 572  * %-EIO - I/O error.
 573  *
 574  * %-ENOMEM - Insufficient amount of memory available.
 575  */
 576 int nilfs_sufile_get_stat(struct inode *sufile, struct nilfs_sustat *sustat)
 577 {
 578         struct buffer_head *header_bh;
 579         struct nilfs_sufile_header *header;
 580         struct the_nilfs *nilfs = NILFS_MDT(sufile)->mi_nilfs;
 581         void *kaddr;
 582         int ret;
 583
 584         down_read(&NILFS_MDT(sufile)->mi_sem);
 585
 586         ret = nilfs_sufile_get_header_block(sufile, &header_bh);
 587         if (ret < 0)
 588                 goto out_sem;
 589
 590         kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
 591         header = kaddr + bh_offset(header_bh);
 592         sustat->ss_nsegs = nilfs_sufile_get_nsegments(sufile);
 593         sustat->ss_ncleansegs = le64_to_cpu(header->sh_ncleansegs);
 594         sustat->ss_ndirtysegs = le64_to_cpu(header->sh_ndirtysegs);
 595         sustat->ss_ctime = nilfs->ns_ctime;
 596         sustat->ss_nongc_ctime = nilfs->ns_nongc_ctime;
 597         spin_lock(&nilfs->ns_last_segment_lock);
 598         sustat->ss_prot_seq = nilfs->ns_prot_seq;
 599         spin_unlock(&nilfs->ns_last_segment_lock);
 600         kunmap_atomic(kaddr, KM_USER0);
 601         brelse(header_bh);
 602
 603  out_sem:
 604         up_read(&NILFS_MDT(sufile)->mi_sem);
 605         return ret;
 606 }
 607
 608 void nilfs_sufile_do_set_error(struct inode *sufile, __u64 segnum,
 609                                struct buffer_head *header_bh,
 610                                struct buffer_head *su_bh)
 611 {
 612         struct nilfs_segment_usage *su;
 613         void *kaddr;
 614         int suclean;
 615
 616         kaddr = kmap_atomic(su_bh->b_page, KM_USER0);
 617         su = nilfs_sufile_block_get_segment_usage(sufile, segnum, su_bh, kaddr);
 618         if (nilfs_segment_usage_error(su)) {
 619                 kunmap_atomic(kaddr, KM_USER0);
 620                 return;
 621         }
 622         suclean = nilfs_segment_usage_clean(su);
 623         nilfs_segment_usage_set_error(su);
 624         kunmap_atomic(kaddr, KM_USER0);
 625
 626         if (suclean) {
 627                 nilfs_sufile_mod_counter(header_bh, -1, 0);
 628                 NILFS_SUI(sufile)->ncleansegs--;
 629         }
 630         nilfs_mdt_mark_buffer_dirty(su_bh);
 631         nilfs_mdt_mark_dirty(sufile);
 632 }
 633
 634 /**
 635  * nilfs_sufile_get_suinfo -
 636  * @sufile: inode of segment usage file
 637  * @segnum: segment number to start looking
 638  * @buf: array of suinfo
 639  * @sisz: byte size of suinfo
 640  * @nsi: size of suinfo array
 641  *
 642  * Description:
 643  *
 644  * Return Value: On success, 0 is returned and .... On error, one of the
 645  * following negative error codes is returned.
 646  *
 647  * %-EIO - I/O error.
 648  *
 649  * %-ENOMEM - Insufficient amount of memory available.
 650  */
 651 ssize_t nilfs_sufile_get_suinfo(struct inode *sufile, __u64 segnum, void *buf,
 652                                 unsigned sisz, size_t nsi)
 653 {
 654         struct buffer_head *su_bh;
 655         struct nilfs_segment_usage *su;
 656         struct nilfs_suinfo *si = buf;
 657         size_t susz = NILFS_MDT(sufile)->mi_entry_size;
 658         struct the_nilfs *nilfs = NILFS_MDT(sufile)->mi_nilfs;
 659         void *kaddr;
 660         unsigned long nsegs, segusages_per_block;
 661         ssize_t n;
 662         int ret, i, j;
 663
 664         down_read(&NILFS_MDT(sufile)->mi_sem);
 665
 666         segusages_per_block = nilfs_sufile_segment_usages_per_block(sufile);
 667         nsegs = min_t(unsigned long,
 668                       nilfs_sufile_get_nsegments(sufile) - segnum,
 669                       nsi);
 670         for (i = 0; i < nsegs; i += n, segnum += n) {
 671                 n = min_t(unsigned long,
 672                           segusages_per_block -
 673                                   nilfs_sufile_get_offset(sufile, segnum),
 674                           nsegs - i);
 675                 ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 0,
 676                                                            &su_bh);
 677                 if (ret < 0) {
 678                         if (ret != -ENOENT)
 679                                 goto out;
 680                         /* hole */
 681                         memset(si, 0, sisz * n);
 682                         si = (void *)si + sisz * n;
 683                         continue;
 684                 }
 685
 686                 kaddr = kmap_atomic(su_bh->b_page, KM_USER0);
 687                 su = nilfs_sufile_block_get_segment_usage(
 688                         sufile, segnum, su_bh, kaddr);
 689                 for (j = 0; j < n;
 690                      j++, su = (void *)su + susz, si = (void *)si + sisz) {
 691                         si->sui_lastmod = le64_to_cpu(su->su_lastmod);
 692                         si->sui_nblocks = le32_to_cpu(su->su_nblocks);
 693                         si->sui_flags = le32_to_cpu(su->su_flags) &
 694                                 ~(1UL << NILFS_SEGMENT_USAGE_ACTIVE);
 695                         if (nilfs_segment_is_active(nilfs, segnum + j))
 696                                 si->sui_flags |=
 697                                         (1UL << NILFS_SEGMENT_USAGE_ACTIVE);
 698                 }
 699                 kunmap_atomic(kaddr, KM_USER0);
 700                 brelse(su_bh);
 701         }
 702         ret = nsegs;
 703
 704  out:
 705         up_read(&NILFS_MDT(sufile)->mi_sem);
 706         return ret;
 707 }
 708
 709 /**
 710  * nilfs_sufile_read - read sufile inode
 711  * @sufile: sufile inode
 712  * @raw_inode: on-disk sufile inode
 713  */
 714 int nilfs_sufile_read(struct inode *sufile, struct nilfs_inode *raw_inode)
 715 {
 716         struct nilfs_sufile_info *sui = NILFS_SUI(sufile);
 717         struct buffer_head *header_bh;
 718         struct nilfs_sufile_header *header;
 719         void *kaddr;
 720         int ret;
 721
 722         ret = nilfs_read_inode_common(sufile, raw_inode);
 723         if (ret < 0)
 724                 return ret;
 725
 726         ret = nilfs_sufile_get_header_block(sufile, &header_bh);
 727         if (!ret) {
 728                 kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
 729                 header = kaddr + bh_offset(header_bh);
 730                 sui->ncleansegs = le64_to_cpu(header->sh_ncleansegs);
 731                 kunmap_atomic(kaddr, KM_USER0);
 732                 brelse(header_bh);
 733         }
 734         return ret;
 735 }
 736
 737 /**
 738  * nilfs_sufile_new - create sufile
 739  * @nilfs: nilfs object
 740  * @susize: size of a segment usage entry
 741  */
 742 struct inode *nilfs_sufile_new(struct the_nilfs *nilfs, size_t susize)
 743 {
 744         struct inode *sufile;
 745
 746         sufile = nilfs_mdt_new(nilfs, NULL, NILFS_SUFILE_INO,
 747                                sizeof(struct nilfs_sufile_info));
 748         if (sufile)
 749                 nilfs_mdt_set_entry_size(sufile, susize,
 750                                          sizeof(struct nilfs_sufile_header));
 751         return sufile;
 752 }