linux/fs/nilfs2/sufile.c
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   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 */
  40struct 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
  47static inline struct nilfs_sufile_info *NILFS_SUI(struct inode *sufile)
  48{
  49        return (struct nilfs_sufile_info *)NILFS_MDT(sufile);
  50}
  51
  52static inline unsigned long
  53nilfs_sufile_segment_usages_per_block(const struct inode *sufile)
  54{
  55        return NILFS_MDT(sufile)->mi_entries_per_block;
  56}
  57
  58static unsigned long
  59nilfs_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
  66static unsigned long
  67nilfs_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
  73static unsigned long
  74nilfs_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
  83static struct nilfs_segment_usage *
  84nilfs_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
  92static 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
  98static inline int
  99nilfs_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
 107static 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
 114static 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 */
 133unsigned 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 */
 166int 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
 234int 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 */
 276int 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 */
 311int 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
 409void 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
 434void 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
 465void 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 */
 500int 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 */
 521int 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 */
 567int 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
 599void 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  */
 642static 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
 719out_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);
 726out:
 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 */
 746int 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
 790out_header:
 791        brelse(header_bh);
 792out:
 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 */
 814ssize_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 */
 879int 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}
 928
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