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  * Revised 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 - on-memory private data of sufile
  35  * @mi: on-memory private data of metadata file
  36  * @ncleansegs: number of clean segments
  37  * @allocmin: lower limit of allocatable segment range
  38  * @allocmax: upper limit of allocatable segment range
  39  */
  40 struct nilfs_sufile_info {
  41         struct nilfs_mdt_info mi;
  42         unsigned long ncleansegs;/* number of clean segments */
  43         __u64 allocmin;         /* lower limit of allocatable segment range */
  44         __u64 allocmax;         /* upper limit of allocatable segment range */
  45 };
  46
  47 static inline struct nilfs_sufile_info *NILFS_SUI(struct inode *sufile)
  48 {
  49         return (struct nilfs_sufile_info *)NILFS_MDT(sufile);
  50 }
  51
  52 static inline unsigned long
  53 nilfs_sufile_segment_usages_per_block(const struct inode *sufile)
  54 {
  55         return NILFS_MDT(sufile)->mi_entries_per_block;
  56 }
  57
  58 static unsigned long
  59 nilfs_sufile_get_blkoff(const struct inode *sufile, __u64 segnum)
  60 {
  61         __u64 t = segnum + NILFS_MDT(sufile)->mi_first_entry_offset;
  62         do_div(t, nilfs_sufile_segment_usages_per_block(sufile));
  63         return (unsigned long)t;
  64 }
  65
  66 static unsigned long
  67 nilfs_sufile_get_offset(const struct inode *sufile, __u64 segnum)
  68 {
  69         __u64 t = segnum + NILFS_MDT(sufile)->mi_first_entry_offset;
  70         return do_div(t, nilfs_sufile_segment_usages_per_block(sufile));
  71 }
  72
  73 static unsigned long
  74 nilfs_sufile_segment_usages_in_block(const struct inode *sufile, __u64 curr,
  75                                      __u64 max)
  76 {
  77         return min_t(unsigned long,
  78                      nilfs_sufile_segment_usages_per_block(sufile) -
  79                      nilfs_sufile_get_offset(sufile, curr),
  80                      max - curr + 1);
  81 }
  82
  83 static struct nilfs_segment_usage *
  84 nilfs_sufile_block_get_segment_usage(const struct inode *sufile, __u64 segnum,
  85                                      struct buffer_head *bh, void *kaddr)
  86 {
  87         return kaddr + bh_offset(bh) +
  88                 nilfs_sufile_get_offset(sufile, segnum) *
  89                 NILFS_MDT(sufile)->mi_entry_size;
  90 }
  91
  92 static inline int nilfs_sufile_get_header_block(struct inode *sufile,
  93                                                 struct buffer_head **bhp)
  94 {
  95         return nilfs_mdt_get_block(sufile, 0, 0, NULL, bhp);
  96 }
  97
  98 static inline int
  99 nilfs_sufile_get_segment_usage_block(struct inode *sufile, __u64 segnum,
 100                                      int create, struct buffer_head **bhp)
 101 {
 102         return nilfs_mdt_get_block(sufile,
 103                                    nilfs_sufile_get_blkoff(sufile, segnum),
 104                                    create, NULL, bhp);
 105 }
 106
 107 static int nilfs_sufile_delete_segment_usage_block(struct inode *sufile,
 108                                                    __u64 segnum)
 109 {
 110         return nilfs_mdt_delete_block(sufile,
 111                                       nilfs_sufile_get_blkoff(sufile, segnum));
 112 }
 113
 114 static void nilfs_sufile_mod_counter(struct buffer_head *header_bh,
 115                                      u64 ncleanadd, u64 ndirtyadd)
 116 {
 117         struct nilfs_sufile_header *header;
 118         void *kaddr;
 119
 120         kaddr = kmap_atomic(header_bh->b_page);
 121         header = kaddr + bh_offset(header_bh);
 122         le64_add_cpu(&header->sh_ncleansegs, ncleanadd);
 123         le64_add_cpu(&header->sh_ndirtysegs, ndirtyadd);
 124         kunmap_atomic(kaddr);
 125
 126         mark_buffer_dirty(header_bh);
 127 }
 128
 129 /**
 130  * nilfs_sufile_get_ncleansegs - return the number of clean segments
 131  * @sufile: inode of segment usage file
 132  */
 133 unsigned long nilfs_sufile_get_ncleansegs(struct inode *sufile)
 134 {
 135         return NILFS_SUI(sufile)->ncleansegs;
 136 }
 137
 138 /**
 139  * nilfs_sufile_updatev - modify multiple segment usages at a time
 140  * @sufile: inode of segment usage file
 141  * @segnumv: array of segment numbers
 142  * @nsegs: size of @segnumv array
 143  * @create: creation flag
 144  * @ndone: place to store number of modified segments on @segnumv
 145  * @dofunc: primitive operation for the update
 146  *
 147  * Description: nilfs_sufile_updatev() repeatedly calls @dofunc
 148  * against the given array of segments.  The @dofunc is called with
 149  * buffers of a header block and the sufile block in which the target
 150  * segment usage entry is contained.  If @ndone is given, the number
 151  * of successfully modified segments from the head is stored in the
 152  * place @ndone points to.
 153  *
 154  * Return Value: On success, zero is returned.  On error, one of the
 155  * following negative error codes is returned.
 156  *
 157  * %-EIO - I/O error.
 158  *
 159  * %-ENOMEM - Insufficient amount of memory available.
 160  *
 161  * %-ENOENT - Given segment usage is in hole block (may be returned if
 162  *            @create is zero)
 163  *
 164  * %-EINVAL - Invalid segment usage number
 165  */
 166 int nilfs_sufile_updatev(struct inode *sufile, __u64 *segnumv, size_t nsegs,
 167                          int create, size_t *ndone,
 168                          void (*dofunc)(struct inode *, __u64,
 169                                         struct buffer_head *,
 170                                         struct buffer_head *))
 171 {
 172         struct buffer_head *header_bh, *bh;
 173         unsigned long blkoff, prev_blkoff;
 174         __u64 *seg;
 175         size_t nerr = 0, n = 0;
 176         int ret = 0;
 177
 178         if (unlikely(nsegs == 0))
 179                 goto out;
 180
 181         down_write(&NILFS_MDT(sufile)->mi_sem);
 182         for (seg = segnumv; seg < segnumv + nsegs; seg++) {
 183                 if (unlikely(*seg >= nilfs_sufile_get_nsegments(sufile))) {
 184                         printk(KERN_WARNING
 185                                "%s: invalid segment number: %llu\n", __func__,
 186                                (unsigned long long)*seg);
 187                         nerr++;
 188                 }
 189         }
 190         if (nerr > 0) {
 191                 ret = -EINVAL;
 192                 goto out_sem;
 193         }
 194
 195         ret = nilfs_sufile_get_header_block(sufile, &header_bh);
 196         if (ret < 0)
 197                 goto out_sem;
 198
 199         seg = segnumv;
 200         blkoff = nilfs_sufile_get_blkoff(sufile, *seg);
 201         ret = nilfs_mdt_get_block(sufile, blkoff, create, NULL, &bh);
 202         if (ret < 0)
 203                 goto out_header;
 204
 205         for (;;) {
 206                 dofunc(sufile, *seg, header_bh, bh);
 207
 208                 if (++seg >= segnumv + nsegs)
 209                         break;
 210                 prev_blkoff = blkoff;
 211                 blkoff = nilfs_sufile_get_blkoff(sufile, *seg);
 212                 if (blkoff == prev_blkoff)
 213                         continue;
 214
 215                 /* get different block */
 216                 brelse(bh);
 217                 ret = nilfs_mdt_get_block(sufile, blkoff, create, NULL, &bh);
 218                 if (unlikely(ret < 0))
 219                         goto out_header;
 220         }
 221         brelse(bh);
 222
 223  out_header:
 224         n = seg - segnumv;
 225         brelse(header_bh);
 226  out_sem:
 227         up_write(&NILFS_MDT(sufile)->mi_sem);
 228  out:
 229         if (ndone)
 230                 *ndone = n;
 231         return ret;
 232 }
 233
 234 int nilfs_sufile_update(struct inode *sufile, __u64 segnum, int create,
 235                         void (*dofunc)(struct inode *, __u64,
 236                                        struct buffer_head *,
 237                                        struct buffer_head *))
 238 {
 239         struct buffer_head *header_bh, *bh;
 240         int ret;
 241
 242         if (unlikely(segnum >= nilfs_sufile_get_nsegments(sufile))) {
 243                 printk(KERN_WARNING "%s: invalid segment number: %llu\n",
 244                        __func__, (unsigned long long)segnum);
 245                 return -EINVAL;
 246         }
 247         down_write(&NILFS_MDT(sufile)->mi_sem);
 248
 249         ret = nilfs_sufile_get_header_block(sufile, &header_bh);
 250         if (ret < 0)
 251                 goto out_sem;
 252
 253         ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, create, &bh);
 254         if (!ret) {
 255                 dofunc(sufile, segnum, header_bh, bh);
 256                 brelse(bh);
 257         }
 258         brelse(header_bh);
 259
 260  out_sem:
 261         up_write(&NILFS_MDT(sufile)->mi_sem);
 262         return ret;
 263 }
 264
 265 /**
 266  * nilfs_sufile_set_alloc_range - limit range of segment to be allocated
 267  * @sufile: inode of segment usage file
 268  * @start: minimum segment number of allocatable region (inclusive)
 269  * @end: maximum segment number of allocatable region (inclusive)
 270  *
 271  * Return Value: On success, 0 is returned.  On error, one of the
 272  * following negative error codes is returned.
 273  *
 274  * %-ERANGE - invalid segment region
 275  */
 276 int nilfs_sufile_set_alloc_range(struct inode *sufile, __u64 start, __u64 end)
 277 {
 278         struct nilfs_sufile_info *sui = NILFS_SUI(sufile);
 279         __u64 nsegs;
 280         int ret = -ERANGE;
 281
 282         down_write(&NILFS_MDT(sufile)->mi_sem);
 283         nsegs = nilfs_sufile_get_nsegments(sufile);
 284
 285         if (start <= end && end < nsegs) {
 286                 sui->allocmin = start;
 287                 sui->allocmax = end;
 288                 ret = 0;
 289         }
 290         up_write(&NILFS_MDT(sufile)->mi_sem);
 291         return ret;
 292 }
 293
 294 /**
 295  * nilfs_sufile_alloc - allocate a segment
 296  * @sufile: inode of segment usage file
 297  * @segnump: pointer to segment number
 298  *
 299  * Description: nilfs_sufile_alloc() allocates a clean segment.
 300  *
 301  * Return Value: On success, 0 is returned and the segment number of the
 302  * allocated segment is stored in the place pointed by @segnump. On error, one
 303  * of the following negative error codes is returned.
 304  *
 305  * %-EIO - I/O error.
 306  *
 307  * %-ENOMEM - Insufficient amount of memory available.
 308  *
 309  * %-ENOSPC - No clean segment left.
 310  */
 311 int nilfs_sufile_alloc(struct inode *sufile, __u64 *segnump)
 312 {
 313         struct buffer_head *header_bh, *su_bh;
 314         struct nilfs_sufile_header *header;
 315         struct nilfs_segment_usage *su;
 316         struct nilfs_sufile_info *sui = NILFS_SUI(sufile);
 317         size_t susz = NILFS_MDT(sufile)->mi_entry_size;
 318         __u64 segnum, maxsegnum, last_alloc;
 319         void *kaddr;
 320         unsigned long nsegments, ncleansegs, nsus, cnt;
 321         int ret, j;
 322
 323         down_write(&NILFS_MDT(sufile)->mi_sem);
 324
 325         ret = nilfs_sufile_get_header_block(sufile, &header_bh);
 326         if (ret < 0)
 327                 goto out_sem;
 328         kaddr = kmap_atomic(header_bh->b_page);
 329         header = kaddr + bh_offset(header_bh);
 330         ncleansegs = le64_to_cpu(header->sh_ncleansegs);
 331         last_alloc = le64_to_cpu(header->sh_last_alloc);
 332         kunmap_atomic(kaddr);
 333
 334         nsegments = nilfs_sufile_get_nsegments(sufile);
 335         maxsegnum = sui->allocmax;
 336         segnum = last_alloc + 1;
 337         if (segnum < sui->allocmin || segnum > sui->allocmax)
 338                 segnum = sui->allocmin;
 339
 340         for (cnt = 0; cnt < nsegments; cnt += nsus) {
 341                 if (segnum > maxsegnum) {
 342                         if (cnt < sui->allocmax - sui->allocmin + 1) {
 343                                 /*
 344                                  * wrap around in the limited region.
 345                                  * if allocation started from
 346                                  * sui->allocmin, this never happens.
 347                                  */
 348                                 segnum = sui->allocmin;
 349                                 maxsegnum = last_alloc;
 350                         } else if (segnum > sui->allocmin &&
 351                                    sui->allocmax + 1 < nsegments) {
 352                                 segnum = sui->allocmax + 1;
 353                                 maxsegnum = nsegments - 1;
 354                         } else if (sui->allocmin > 0)  {
 355                                 segnum = 0;
 356                                 maxsegnum = sui->allocmin - 1;
 357                         } else {
 358                                 break; /* never happens */
 359                         }
 360                 }
 361                 ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 1,
 362                                                            &su_bh);
 363                 if (ret < 0)
 364                         goto out_header;
 365                 kaddr = kmap_atomic(su_bh->b_page);
 366                 su = nilfs_sufile_block_get_segment_usage(
 367                         sufile, segnum, su_bh, kaddr);
 368
 369                 nsus = nilfs_sufile_segment_usages_in_block(
 370                         sufile, segnum, maxsegnum);
 371                 for (j = 0; j < nsus; j++, su = (void *)su + susz, segnum++) {
 372                         if (!nilfs_segment_usage_clean(su))
 373                                 continue;
 374                         /* found a clean segment */
 375                         nilfs_segment_usage_set_dirty(su);
 376                         kunmap_atomic(kaddr);
 377
 378                         kaddr = kmap_atomic(header_bh->b_page);
 379                         header = kaddr + bh_offset(header_bh);
 380                         le64_add_cpu(&header->sh_ncleansegs, -1);
 381                         le64_add_cpu(&header->sh_ndirtysegs, 1);
 382                         header->sh_last_alloc = cpu_to_le64(segnum);
 383                         kunmap_atomic(kaddr);
 384
 385                         sui->ncleansegs--;
 386                         mark_buffer_dirty(header_bh);
 387                         mark_buffer_dirty(su_bh);
 388                         nilfs_mdt_mark_dirty(sufile);
 389                         brelse(su_bh);
 390                         *segnump = segnum;
 391                         goto out_header;
 392                 }
 393
 394                 kunmap_atomic(kaddr);
 395                 brelse(su_bh);
 396         }
 397
 398         /* no segments left */
 399         ret = -ENOSPC;
 400
 401  out_header:
 402         brelse(header_bh);
 403
 404  out_sem:
 405         up_write(&NILFS_MDT(sufile)->mi_sem);
 406         return ret;
 407 }
 408
 409 void nilfs_sufile_do_cancel_free(struct inode *sufile, __u64 segnum,
 410                                  struct buffer_head *header_bh,
 411                                  struct buffer_head *su_bh)
 412 {
 413         struct nilfs_segment_usage *su;
 414         void *kaddr;
 415
 416         kaddr = kmap_atomic(su_bh->b_page);
 417         su = nilfs_sufile_block_get_segment_usage(sufile, segnum, su_bh, kaddr);
 418         if (unlikely(!nilfs_segment_usage_clean(su))) {
 419                 printk(KERN_WARNING "%s: segment %llu must be clean\n",
 420                        __func__, (unsigned long long)segnum);
 421                 kunmap_atomic(kaddr);
 422                 return;
 423         }
 424         nilfs_segment_usage_set_dirty(su);
 425         kunmap_atomic(kaddr);
 426
 427         nilfs_sufile_mod_counter(header_bh, -1, 1);
 428         NILFS_SUI(sufile)->ncleansegs--;
 429
 430         mark_buffer_dirty(su_bh);
 431         nilfs_mdt_mark_dirty(sufile);
 432 }
 433
 434 void nilfs_sufile_do_scrap(struct inode *sufile, __u64 segnum,
 435                            struct buffer_head *header_bh,
 436                            struct buffer_head *su_bh)
 437 {
 438         struct nilfs_segment_usage *su;
 439         void *kaddr;
 440         int clean, dirty;
 441
 442         kaddr = kmap_atomic(su_bh->b_page);
 443         su = nilfs_sufile_block_get_segment_usage(sufile, segnum, su_bh, kaddr);
 444         if (su->su_flags == cpu_to_le32(1UL << NILFS_SEGMENT_USAGE_DIRTY) &&
 445             su->su_nblocks == cpu_to_le32(0)) {
 446                 kunmap_atomic(kaddr);
 447                 return;
 448         }
 449         clean = nilfs_segment_usage_clean(su);
 450         dirty = nilfs_segment_usage_dirty(su);
 451
 452         /* make the segment garbage */
 453         su->su_lastmod = cpu_to_le64(0);
 454         su->su_nblocks = cpu_to_le32(0);
 455         su->su_flags = cpu_to_le32(1UL << NILFS_SEGMENT_USAGE_DIRTY);
 456         kunmap_atomic(kaddr);
 457
 458         nilfs_sufile_mod_counter(header_bh, clean ? (u64)-1 : 0, dirty ? 0 : 1);
 459         NILFS_SUI(sufile)->ncleansegs -= clean;
 460
 461         mark_buffer_dirty(su_bh);
 462         nilfs_mdt_mark_dirty(sufile);
 463 }
 464
 465 void nilfs_sufile_do_free(struct inode *sufile, __u64 segnum,
 466                           struct buffer_head *header_bh,
 467                           struct buffer_head *su_bh)
 468 {
 469         struct nilfs_segment_usage *su;
 470         void *kaddr;
 471         int sudirty;
 472
 473         kaddr = kmap_atomic(su_bh->b_page);
 474         su = nilfs_sufile_block_get_segment_usage(sufile, segnum, su_bh, kaddr);
 475         if (nilfs_segment_usage_clean(su)) {
 476                 printk(KERN_WARNING "%s: segment %llu is already clean\n",
 477                        __func__, (unsigned long long)segnum);
 478                 kunmap_atomic(kaddr);
 479                 return;
 480         }
 481         WARN_ON(nilfs_segment_usage_error(su));
 482         WARN_ON(!nilfs_segment_usage_dirty(su));
 483
 484         sudirty = nilfs_segment_usage_dirty(su);
 485         nilfs_segment_usage_set_clean(su);
 486         kunmap_atomic(kaddr);
 487         mark_buffer_dirty(su_bh);
 488
 489         nilfs_sufile_mod_counter(header_bh, 1, sudirty ? (u64)-1 : 0);
 490         NILFS_SUI(sufile)->ncleansegs++;
 491
 492         nilfs_mdt_mark_dirty(sufile);
 493 }
 494
 495 /**
 496  * nilfs_sufile_mark_dirty - mark the buffer having a segment usage dirty
 497  * @sufile: inode of segment usage file
 498  * @segnum: segment number
 499  */
 500 int nilfs_sufile_mark_dirty(struct inode *sufile, __u64 segnum)
 501 {
 502         struct buffer_head *bh;
 503         int ret;
 504
 505         ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 0, &bh);
 506         if (!ret) {
 507                 mark_buffer_dirty(bh);
 508                 nilfs_mdt_mark_dirty(sufile);
 509                 brelse(bh);
 510         }
 511         return ret;
 512 }
 513
 514 /**
 515  * nilfs_sufile_set_segment_usage - set usage of a segment
 516  * @sufile: inode of segment usage file
 517  * @segnum: segment number
 518  * @nblocks: number of live blocks in the segment
 519  * @modtime: modification time (option)
 520  */
 521 int nilfs_sufile_set_segment_usage(struct inode *sufile, __u64 segnum,
 522                                    unsigned long nblocks, time_t modtime)
 523 {
 524         struct buffer_head *bh;
 525         struct nilfs_segment_usage *su;
 526         void *kaddr;
 527         int ret;
 528
 529         down_write(&NILFS_MDT(sufile)->mi_sem);
 530         ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 0, &bh);
 531         if (ret < 0)
 532                 goto out_sem;
 533
 534         kaddr = kmap_atomic(bh->b_page);
 535         su = nilfs_sufile_block_get_segment_usage(sufile, segnum, bh, kaddr);
 536         WARN_ON(nilfs_segment_usage_error(su));
 537         if (modtime)
 538                 su->su_lastmod = cpu_to_le64(modtime);
 539         su->su_nblocks = cpu_to_le32(nblocks);
 540         kunmap_atomic(kaddr);
 541
 542         mark_buffer_dirty(bh);
 543         nilfs_mdt_mark_dirty(sufile);
 544         brelse(bh);
 545
 546  out_sem:
 547         up_write(&NILFS_MDT(sufile)->mi_sem);
 548         return ret;
 549 }
 550
 551 /**
 552  * nilfs_sufile_get_stat - get segment usage statistics
 553  * @sufile: inode of segment usage file
 554  * @stat: pointer to a structure of segment usage statistics
 555  *
 556  * Description: nilfs_sufile_get_stat() returns information about segment
 557  * usage.
 558  *
 559  * Return Value: On success, 0 is returned, and segment usage information is
 560  * stored in the place pointed by @stat. On error, one of the following
 561  * negative error codes is returned.
 562  *
 563  * %-EIO - I/O error.
 564  *
 565  * %-ENOMEM - Insufficient amount of memory available.
 566  */
 567 int nilfs_sufile_get_stat(struct inode *sufile, struct nilfs_sustat *sustat)
 568 {
 569         struct buffer_head *header_bh;
 570         struct nilfs_sufile_header *header;
 571         struct the_nilfs *nilfs = sufile->i_sb->s_fs_info;
 572         void *kaddr;
 573         int ret;
 574
 575         down_read(&NILFS_MDT(sufile)->mi_sem);
 576
 577         ret = nilfs_sufile_get_header_block(sufile, &header_bh);
 578         if (ret < 0)
 579                 goto out_sem;
 580
 581         kaddr = kmap_atomic(header_bh->b_page);
 582         header = kaddr + bh_offset(header_bh);
 583         sustat->ss_nsegs = nilfs_sufile_get_nsegments(sufile);
 584         sustat->ss_ncleansegs = le64_to_cpu(header->sh_ncleansegs);
 585         sustat->ss_ndirtysegs = le64_to_cpu(header->sh_ndirtysegs);
 586         sustat->ss_ctime = nilfs->ns_ctime;
 587         sustat->ss_nongc_ctime = nilfs->ns_nongc_ctime;
 588         spin_lock(&nilfs->ns_last_segment_lock);
 589         sustat->ss_prot_seq = nilfs->ns_prot_seq;
 590         spin_unlock(&nilfs->ns_last_segment_lock);
 591         kunmap_atomic(kaddr);
 592         brelse(header_bh);
 593
 594  out_sem:
 595         up_read(&NILFS_MDT(sufile)->mi_sem);
 596         return ret;
 597 }
 598
 599 void nilfs_sufile_do_set_error(struct inode *sufile, __u64 segnum,
 600                                struct buffer_head *header_bh,
 601                                struct buffer_head *su_bh)
 602 {
 603         struct nilfs_segment_usage *su;
 604         void *kaddr;
 605         int suclean;
 606
 607         kaddr = kmap_atomic(su_bh->b_page);
 608         su = nilfs_sufile_block_get_segment_usage(sufile, segnum, su_bh, kaddr);
 609         if (nilfs_segment_usage_error(su)) {
 610                 kunmap_atomic(kaddr);
 611                 return;
 612         }
 613         suclean = nilfs_segment_usage_clean(su);
 614         nilfs_segment_usage_set_error(su);
 615         kunmap_atomic(kaddr);
 616
 617         if (suclean) {
 618                 nilfs_sufile_mod_counter(header_bh, -1, 0);
 619                 NILFS_SUI(sufile)->ncleansegs--;
 620         }
 621         mark_buffer_dirty(su_bh);
 622         nilfs_mdt_mark_dirty(sufile);
 623 }
 624
 625 /**
 626   * nilfs_sufile_truncate_range - truncate range of segment array
 627   * @sufile: inode of segment usage file
 628   * @start: start segment number (inclusive)
 629   * @end: end segment number (inclusive)
 630   *
 631   * Return Value: On success, 0 is returned.  On error, one of the
 632   * following negative error codes is returned.
 633   *
 634   * %-EIO - I/O error.
 635   *
 636   * %-ENOMEM - Insufficient amount of memory available.
 637   *
 638   * %-EINVAL - Invalid number of segments specified
 639   *
 640   * %-EBUSY - Dirty or active segments are present in the range
 641   */
 642 static int nilfs_sufile_truncate_range(struct inode *sufile,
 643                                        __u64 start, __u64 end)
 644 {
 645         struct the_nilfs *nilfs = sufile->i_sb->s_fs_info;
 646         struct buffer_head *header_bh;
 647         struct buffer_head *su_bh;
 648         struct nilfs_segment_usage *su, *su2;
 649         size_t susz = NILFS_MDT(sufile)->mi_entry_size;
 650         unsigned long segusages_per_block;
 651         unsigned long nsegs, ncleaned;
 652         __u64 segnum;
 653         void *kaddr;
 654         ssize_t n, nc;
 655         int ret;
 656         int j;
 657
 658         nsegs = nilfs_sufile_get_nsegments(sufile);
 659
 660         ret = -EINVAL;
 661         if (start > end || start >= nsegs)
 662                 goto out;
 663
 664         ret = nilfs_sufile_get_header_block(sufile, &header_bh);
 665         if (ret < 0)
 666                 goto out;
 667
 668         segusages_per_block = nilfs_sufile_segment_usages_per_block(sufile);
 669         ncleaned = 0;
 670
 671         for (segnum = start; segnum <= end; segnum += n) {
 672                 n = min_t(unsigned long,
 673                           segusages_per_block -
 674                                   nilfs_sufile_get_offset(sufile, segnum),
 675                           end - segnum + 1);
 676                 ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 0,
 677                                                            &su_bh);
 678                 if (ret < 0) {
 679                         if (ret != -ENOENT)
 680                                 goto out_header;
 681                         /* hole */
 682                         continue;
 683                 }
 684                 kaddr = kmap_atomic(su_bh->b_page);
 685                 su = nilfs_sufile_block_get_segment_usage(
 686                         sufile, segnum, su_bh, kaddr);
 687                 su2 = su;
 688                 for (j = 0; j < n; j++, su = (void *)su + susz) {
 689                         if ((le32_to_cpu(su->su_flags) &
 690                              ~(1UL << NILFS_SEGMENT_USAGE_ERROR)) ||
 691                             nilfs_segment_is_active(nilfs, segnum + j)) {
 692                                 ret = -EBUSY;
 693                                 kunmap_atomic(kaddr);
 694                                 brelse(su_bh);
 695                                 goto out_header;
 696                         }
 697                 }
 698                 nc = 0;
 699                 for (su = su2, j = 0; j < n; j++, su = (void *)su + susz) {
 700                         if (nilfs_segment_usage_error(su)) {
 701                                 nilfs_segment_usage_set_clean(su);
 702                                 nc++;
 703                         }
 704                 }
 705                 kunmap_atomic(kaddr);
 706                 if (nc > 0) {
 707                         mark_buffer_dirty(su_bh);
 708                         ncleaned += nc;
 709                 }
 710                 brelse(su_bh);
 711
 712                 if (n == segusages_per_block) {
 713                         /* make hole */
 714                         nilfs_sufile_delete_segment_usage_block(sufile, segnum);
 715                 }
 716         }
 717         ret = 0;
 718
 719 out_header:
 720         if (ncleaned > 0) {
 721                 NILFS_SUI(sufile)->ncleansegs += ncleaned;
 722                 nilfs_sufile_mod_counter(header_bh, ncleaned, 0);
 723                 nilfs_mdt_mark_dirty(sufile);
 724         }
 725         brelse(header_bh);
 726 out:
 727         return ret;
 728 }
 729
 730 /**
 731  * nilfs_sufile_resize - resize segment array
 732  * @sufile: inode of segment usage file
 733  * @newnsegs: new number of segments
 734  *
 735  * Return Value: On success, 0 is returned.  On error, one of the
 736  * following negative error codes is returned.
 737  *
 738  * %-EIO - I/O error.
 739  *
 740  * %-ENOMEM - Insufficient amount of memory available.
 741  *
 742  * %-ENOSPC - Enough free space is not left for shrinking
 743  *
 744  * %-EBUSY - Dirty or active segments exist in the region to be truncated
 745  */
 746 int nilfs_sufile_resize(struct inode *sufile, __u64 newnsegs)
 747 {
 748         struct the_nilfs *nilfs = sufile->i_sb->s_fs_info;
 749         struct buffer_head *header_bh;
 750         struct nilfs_sufile_header *header;
 751         struct nilfs_sufile_info *sui = NILFS_SUI(sufile);
 752         void *kaddr;
 753         unsigned long nsegs, nrsvsegs;
 754         int ret = 0;
 755
 756         down_write(&NILFS_MDT(sufile)->mi_sem);
 757
 758         nsegs = nilfs_sufile_get_nsegments(sufile);
 759         if (nsegs == newnsegs)
 760                 goto out;
 761
 762         ret = -ENOSPC;
 763         nrsvsegs = nilfs_nrsvsegs(nilfs, newnsegs);
 764         if (newnsegs < nsegs && nsegs - newnsegs + nrsvsegs > sui->ncleansegs)
 765                 goto out;
 766
 767         ret = nilfs_sufile_get_header_block(sufile, &header_bh);
 768         if (ret < 0)
 769                 goto out;
 770
 771         if (newnsegs > nsegs) {
 772                 sui->ncleansegs += newnsegs - nsegs;
 773         } else /* newnsegs < nsegs */ {
 774                 ret = nilfs_sufile_truncate_range(sufile, newnsegs, nsegs - 1);
 775                 if (ret < 0)
 776                         goto out_header;
 777
 778                 sui->ncleansegs -= nsegs - newnsegs;
 779         }
 780
 781         kaddr = kmap_atomic(header_bh->b_page);
 782         header = kaddr + bh_offset(header_bh);
 783         header->sh_ncleansegs = cpu_to_le64(sui->ncleansegs);
 784         kunmap_atomic(kaddr);
 785
 786         mark_buffer_dirty(header_bh);
 787         nilfs_mdt_mark_dirty(sufile);
 788         nilfs_set_nsegments(nilfs, newnsegs);
 789
 790 out_header:
 791         brelse(header_bh);
 792 out:
 793         up_write(&NILFS_MDT(sufile)->mi_sem);
 794         return ret;
 795 }
 796
 797 /**
 798  * nilfs_sufile_get_suinfo -
 799  * @sufile: inode of segment usage file
 800  * @segnum: segment number to start looking
 801  * @buf: array of suinfo
 802  * @sisz: byte size of suinfo
 803  * @nsi: size of suinfo array
 804  *
 805  * Description:
 806  *
 807  * Return Value: On success, 0 is returned and .... On error, one of the
 808  * following negative error codes is returned.
 809  *
 810  * %-EIO - I/O error.
 811  *
 812  * %-ENOMEM - Insufficient amount of memory available.
 813  */
 814 ssize_t nilfs_sufile_get_suinfo(struct inode *sufile, __u64 segnum, void *buf,
 815                                 unsigned sisz, size_t nsi)
 816 {
 817         struct buffer_head *su_bh;
 818         struct nilfs_segment_usage *su;
 819         struct nilfs_suinfo *si = buf;
 820         size_t susz = NILFS_MDT(sufile)->mi_entry_size;
 821         struct the_nilfs *nilfs = sufile->i_sb->s_fs_info;
 822         void *kaddr;
 823         unsigned long nsegs, segusages_per_block;
 824         ssize_t n;
 825         int ret, i, j;
 826
 827         down_read(&NILFS_MDT(sufile)->mi_sem);
 828
 829         segusages_per_block = nilfs_sufile_segment_usages_per_block(sufile);
 830         nsegs = min_t(unsigned long,
 831                       nilfs_sufile_get_nsegments(sufile) - segnum,
 832                       nsi);
 833         for (i = 0; i < nsegs; i += n, segnum += n) {
 834                 n = min_t(unsigned long,
 835                           segusages_per_block -
 836                                   nilfs_sufile_get_offset(sufile, segnum),
 837                           nsegs - i);
 838                 ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 0,
 839                                                            &su_bh);
 840                 if (ret < 0) {
 841                         if (ret != -ENOENT)
 842                                 goto out;
 843                         /* hole */
 844                         memset(si, 0, sisz * n);
 845                         si = (void *)si + sisz * n;
 846                         continue;
 847                 }
 848
 849                 kaddr = kmap_atomic(su_bh->b_page);
 850                 su = nilfs_sufile_block_get_segment_usage(
 851                         sufile, segnum, su_bh, kaddr);
 852                 for (j = 0; j < n;
 853                      j++, su = (void *)su + susz, si = (void *)si + sisz) {
 854                         si->sui_lastmod = le64_to_cpu(su->su_lastmod);
 855                         si->sui_nblocks = le32_to_cpu(su->su_nblocks);
 856                         si->sui_flags = le32_to_cpu(su->su_flags) &
 857                                 ~(1UL << NILFS_SEGMENT_USAGE_ACTIVE);
 858                         if (nilfs_segment_is_active(nilfs, segnum + j))
 859                                 si->sui_flags |=
 860                                         (1UL << NILFS_SEGMENT_USAGE_ACTIVE);
 861                 }
 862                 kunmap_atomic(kaddr);
 863                 brelse(su_bh);
 864         }
 865         ret = nsegs;
 866
 867  out:
 868         up_read(&NILFS_MDT(sufile)->mi_sem);
 869         return ret;
 870 }
 871
 872 /**
 873  * nilfs_sufile_read - read or get sufile inode
 874  * @sb: super block instance
 875  * @susize: size of a segment usage entry
 876  * @raw_inode: on-disk sufile inode
 877  * @inodep: buffer to store the inode
 878  */
 879 int nilfs_sufile_read(struct super_block *sb, size_t susize,
 880                       struct nilfs_inode *raw_inode, struct inode **inodep)
 881 {
 882         struct inode *sufile;
 883         struct nilfs_sufile_info *sui;
 884         struct buffer_head *header_bh;
 885         struct nilfs_sufile_header *header;
 886         void *kaddr;
 887         int err;
 888
 889         sufile = nilfs_iget_locked(sb, NULL, NILFS_SUFILE_INO);
 890         if (unlikely(!sufile))
 891                 return -ENOMEM;
 892         if (!(sufile->i_state & I_NEW))
 893                 goto out;
 894
 895         err = nilfs_mdt_init(sufile, NILFS_MDT_GFP, sizeof(*sui));
 896         if (err)
 897                 goto failed;
 898
 899         nilfs_mdt_set_entry_size(sufile, susize,
 900                                  sizeof(struct nilfs_sufile_header));
 901
 902         err = nilfs_read_inode_common(sufile, raw_inode);
 903         if (err)
 904                 goto failed;
 905
 906         err = nilfs_sufile_get_header_block(sufile, &header_bh);
 907         if (err)
 908                 goto failed;
 909
 910         sui = NILFS_SUI(sufile);
 911         kaddr = kmap_atomic(header_bh->b_page);
 912         header = kaddr + bh_offset(header_bh);
 913         sui->ncleansegs = le64_to_cpu(header->sh_ncleansegs);
 914         kunmap_atomic(kaddr);
 915         brelse(header_bh);
 916
 917         sui->allocmax = nilfs_sufile_get_nsegments(sufile) - 1;
 918         sui->allocmin = 0;
 919
 920         unlock_new_inode(sufile);
 921  out:
 922         *inodep = sufile;
 923         return 0;
 924  failed:
 925         iget_failed(sufile);
 926         return err;
 927 }