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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  */
  22
  23 #include <linux/kernel.h>
  24 #include <linux/fs.h>
  25 #include <linux/string.h>
  26 #include <linux/buffer_head.h>
  27 #include <linux/errno.h>
  28 #include <linux/nilfs2_fs.h>
  29 #include "mdt.h"
  30 #include "sufile.h"
  31
  32
  33 static inline unsigned long
  34 nilfs_sufile_segment_usages_per_block(const struct inode *sufile)
  35 {
  36         return NILFS_MDT(sufile)->mi_entries_per_block;
  37 }
  38
  39 static unsigned long
  40 nilfs_sufile_get_blkoff(const struct inode *sufile, __u64 segnum)
  41 {
  42         __u64 t = segnum + NILFS_MDT(sufile)->mi_first_entry_offset;
  43         do_div(t, nilfs_sufile_segment_usages_per_block(sufile));
  44         return (unsigned long)t;
  45 }
  46
  47 static unsigned long
  48 nilfs_sufile_get_offset(const struct inode *sufile, __u64 segnum)
  49 {
  50         __u64 t = segnum + NILFS_MDT(sufile)->mi_first_entry_offset;
  51         return do_div(t, nilfs_sufile_segment_usages_per_block(sufile));
  52 }
  53
  54 static unsigned long
  55 nilfs_sufile_segment_usages_in_block(const struct inode *sufile, __u64 curr,
  56                                      __u64 max)
  57 {
  58         return min_t(unsigned long,
  59                      nilfs_sufile_segment_usages_per_block(sufile) -
  60                      nilfs_sufile_get_offset(sufile, curr),
  61                      max - curr + 1);
  62 }
  63
  64 static inline struct nilfs_sufile_header *
  65 nilfs_sufile_block_get_header(const struct inode *sufile,
  66                               struct buffer_head *bh,
  67                               void *kaddr)
  68 {
  69         return kaddr + bh_offset(bh);
  70 }
  71
  72 static struct nilfs_segment_usage *
  73 nilfs_sufile_block_get_segment_usage(const struct inode *sufile, __u64 segnum,
  74                                      struct buffer_head *bh, void *kaddr)
  75 {
  76         return kaddr + bh_offset(bh) +
  77                 nilfs_sufile_get_offset(sufile, segnum) *
  78                 NILFS_MDT(sufile)->mi_entry_size;
  79 }
  80
  81 static inline int nilfs_sufile_get_header_block(struct inode *sufile,
  82                                                 struct buffer_head **bhp)
  83 {
  84         return nilfs_mdt_get_block(sufile, 0, 0, NULL, bhp);
  85 }
  86
  87 static inline int
  88 nilfs_sufile_get_segment_usage_block(struct inode *sufile, __u64 segnum,
  89                                      int create, struct buffer_head **bhp)
  90 {
  91         return nilfs_mdt_get_block(sufile,
  92                                    nilfs_sufile_get_blkoff(sufile, segnum),
  93                                    create, NULL, bhp);
  94 }
  95
  96 static void nilfs_sufile_mod_counter(struct buffer_head *header_bh,
  97                                      u64 ncleanadd, u64 ndirtyadd)
  98 {
  99         struct nilfs_sufile_header *header;
 100         void *kaddr;
 101
 102         kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
 103         header = kaddr + bh_offset(header_bh);
 104         le64_add_cpu(&header->sh_ncleansegs, ncleanadd);
 105         le64_add_cpu(&header->sh_ndirtysegs, ndirtyadd);
 106         kunmap_atomic(kaddr, KM_USER0);
 107
 108         nilfs_mdt_mark_buffer_dirty(header_bh);
 109 }
 110
 111 int nilfs_sufile_update(struct inode *sufile, __u64 segnum, int create,
 112                         void (*dofunc)(struct inode *, __u64,
 113                                        struct buffer_head *,
 114                                        struct buffer_head *))
 115 {
 116         struct buffer_head *header_bh, *bh;
 117         int ret;
 118
 119         if (unlikely(segnum >= nilfs_sufile_get_nsegments(sufile))) {
 120                 printk(KERN_WARNING "%s: invalid segment number: %llu\n",
 121                        __func__, (unsigned long long)segnum);
 122                 return -EINVAL;
 123         }
 124         down_write(&NILFS_MDT(sufile)->mi_sem);
 125
 126         ret = nilfs_sufile_get_header_block(sufile, &header_bh);
 127         if (ret < 0)
 128                 goto out_sem;
 129
 130         ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, create, &bh);
 131         if (!ret) {
 132                 dofunc(sufile, segnum, header_bh, bh);
 133                 brelse(bh);
 134         }
 135         brelse(header_bh);
 136
 137  out_sem:
 138         up_write(&NILFS_MDT(sufile)->mi_sem);
 139         return ret;
 140 }
 141
 142 /**
 143  * nilfs_sufile_alloc - allocate a segment
 144  * @sufile: inode of segment usage file
 145  * @segnump: pointer to segment number
 146  *
 147  * Description: nilfs_sufile_alloc() allocates a clean segment.
 148  *
 149  * Return Value: On success, 0 is returned and the segment number of the
 150  * allocated segment is stored in the place pointed by @segnump. On error, one
 151  * of the following negative error codes is returned.
 152  *
 153  * %-EIO - I/O error.
 154  *
 155  * %-ENOMEM - Insufficient amount of memory available.
 156  *
 157  * %-ENOSPC - No clean segment left.
 158  */
 159 int nilfs_sufile_alloc(struct inode *sufile, __u64 *segnump)
 160 {
 161         struct buffer_head *header_bh, *su_bh;
 162         struct nilfs_sufile_header *header;
 163         struct nilfs_segment_usage *su;
 164         size_t susz = NILFS_MDT(sufile)->mi_entry_size;
 165         __u64 segnum, maxsegnum, last_alloc;
 166         void *kaddr;
 167         unsigned long nsegments, ncleansegs, nsus;
 168         int ret, i, j;
 169
 170         down_write(&NILFS_MDT(sufile)->mi_sem);
 171
 172         ret = nilfs_sufile_get_header_block(sufile, &header_bh);
 173         if (ret < 0)
 174                 goto out_sem;
 175         kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
 176         header = nilfs_sufile_block_get_header(sufile, header_bh, kaddr);
 177         ncleansegs = le64_to_cpu(header->sh_ncleansegs);
 178         last_alloc = le64_to_cpu(header->sh_last_alloc);
 179         kunmap_atomic(kaddr, KM_USER0);
 180
 181         nsegments = nilfs_sufile_get_nsegments(sufile);
 182         segnum = last_alloc + 1;
 183         maxsegnum = nsegments - 1;
 184         for (i = 0; i < nsegments; i += nsus) {
 185                 if (segnum >= nsegments) {
 186                         /* wrap around */
 187                         segnum = 0;
 188                         maxsegnum = last_alloc;
 189                 }
 190                 ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 1,
 191                                                            &su_bh);
 192                 if (ret < 0)
 193                         goto out_header;
 194                 kaddr = kmap_atomic(su_bh->b_page, KM_USER0);
 195                 su = nilfs_sufile_block_get_segment_usage(
 196                         sufile, segnum, su_bh, kaddr);
 197
 198                 nsus = nilfs_sufile_segment_usages_in_block(
 199                         sufile, segnum, maxsegnum);
 200                 for (j = 0; j < nsus; j++, su = (void *)su + susz, segnum++) {
 201                         if (!nilfs_segment_usage_clean(su))
 202                                 continue;
 203                         /* found a clean segment */
 204                         nilfs_segment_usage_set_dirty(su);
 205                         kunmap_atomic(kaddr, KM_USER0);
 206
 207                         kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
 208                         header = nilfs_sufile_block_get_header(
 209                                 sufile, header_bh, kaddr);
 210                         le64_add_cpu(&header->sh_ncleansegs, -1);
 211                         le64_add_cpu(&header->sh_ndirtysegs, 1);
 212                         header->sh_last_alloc = cpu_to_le64(segnum);
 213                         kunmap_atomic(kaddr, KM_USER0);
 214
 215                         nilfs_mdt_mark_buffer_dirty(header_bh);
 216                         nilfs_mdt_mark_buffer_dirty(su_bh);
 217                         nilfs_mdt_mark_dirty(sufile);
 218                         brelse(su_bh);
 219                         *segnump = segnum;
 220                         goto out_header;
 221                 }
 222
 223                 kunmap_atomic(kaddr, KM_USER0);
 224                 brelse(su_bh);
 225         }
 226
 227         /* no segments left */
 228         ret = -ENOSPC;
 229
 230  out_header:
 231         brelse(header_bh);
 232
 233  out_sem:
 234         up_write(&NILFS_MDT(sufile)->mi_sem);
 235         return ret;
 236 }
 237
 238 void nilfs_sufile_do_cancel_free(struct inode *sufile, __u64 segnum,
 239                                  struct buffer_head *header_bh,
 240                                  struct buffer_head *su_bh)
 241 {
 242         struct nilfs_segment_usage *su;
 243         void *kaddr;
 244
 245         kaddr = kmap_atomic(su_bh->b_page, KM_USER0);
 246         su = nilfs_sufile_block_get_segment_usage(sufile, segnum, su_bh, kaddr);
 247         if (unlikely(!nilfs_segment_usage_clean(su))) {
 248                 printk(KERN_WARNING "%s: segment %llu must be clean\n",
 249                        __func__, (unsigned long long)segnum);
 250                 kunmap_atomic(kaddr, KM_USER0);
 251                 return;
 252         }
 253         nilfs_segment_usage_set_dirty(su);
 254         kunmap_atomic(kaddr, KM_USER0);
 255
 256         nilfs_sufile_mod_counter(header_bh, -1, 1);
 257         nilfs_mdt_mark_buffer_dirty(su_bh);
 258         nilfs_mdt_mark_dirty(sufile);
 259 }
 260
 261 void nilfs_sufile_do_scrap(struct inode *sufile, __u64 segnum,
 262                            struct buffer_head *header_bh,
 263                            struct buffer_head *su_bh)
 264 {
 265         struct nilfs_segment_usage *su;
 266         void *kaddr;
 267         int clean, dirty;
 268
 269         kaddr = kmap_atomic(su_bh->b_page, KM_USER0);
 270         su = nilfs_sufile_block_get_segment_usage(sufile, segnum, su_bh, kaddr);
 271         if (su->su_flags == cpu_to_le32(1UL << NILFS_SEGMENT_USAGE_DIRTY) &&
 272             su->su_nblocks == cpu_to_le32(0)) {
 273                 kunmap_atomic(kaddr, KM_USER0);
 274                 return;
 275         }
 276         clean = nilfs_segment_usage_clean(su);
 277         dirty = nilfs_segment_usage_dirty(su);
 278
 279         /* make the segment garbage */
 280         su->su_lastmod = cpu_to_le64(0);
 281         su->su_nblocks = cpu_to_le32(0);
 282         su->su_flags = cpu_to_le32(1UL << NILFS_SEGMENT_USAGE_DIRTY);
 283         kunmap_atomic(kaddr, KM_USER0);
 284
 285         nilfs_sufile_mod_counter(header_bh, clean ? (u64)-1 : 0, dirty ? 0 : 1);
 286         nilfs_mdt_mark_buffer_dirty(su_bh);
 287         nilfs_mdt_mark_dirty(sufile);
 288 }
 289
 290 void nilfs_sufile_do_free(struct inode *sufile, __u64 segnum,
 291                           struct buffer_head *header_bh,
 292                           struct buffer_head *su_bh)
 293 {
 294         struct nilfs_segment_usage *su;
 295         void *kaddr;
 296         int sudirty;
 297
 298         kaddr = kmap_atomic(su_bh->b_page, KM_USER0);
 299         su = nilfs_sufile_block_get_segment_usage(sufile, segnum, su_bh, kaddr);
 300         if (nilfs_segment_usage_clean(su)) {
 301                 printk(KERN_WARNING "%s: segment %llu is already clean\n",
 302                        __func__, (unsigned long long)segnum);
 303                 kunmap_atomic(kaddr, KM_USER0);
 304                 return;
 305         }
 306         WARN_ON(nilfs_segment_usage_error(su));
 307         WARN_ON(!nilfs_segment_usage_dirty(su));
 308
 309         sudirty = nilfs_segment_usage_dirty(su);
 310         nilfs_segment_usage_set_clean(su);
 311         kunmap_atomic(kaddr, KM_USER0);
 312         nilfs_mdt_mark_buffer_dirty(su_bh);
 313
 314         nilfs_sufile_mod_counter(header_bh, 1, sudirty ? (u64)-1 : 0);
 315         nilfs_mdt_mark_dirty(sufile);
 316 }
 317
 318 /**
 319  * nilfs_sufile_get_segment_usage - get a segment usage
 320  * @sufile: inode of segment usage file
 321  * @segnum: segment number
 322  * @sup: pointer to segment usage
 323  * @bhp: pointer to buffer head
 324  *
 325  * Description: nilfs_sufile_get_segment_usage() acquires the segment usage
 326  * specified by @segnum.
 327  *
 328  * Return Value: On success, 0 is returned, and the segment usage and the
 329  * buffer head of the buffer on which the segment usage is located are stored
 330  * in the place pointed by @sup and @bhp, respectively. On error, one of the
 331  * following negative error codes is returned.
 332  *
 333  * %-EIO - I/O error.
 334  *
 335  * %-ENOMEM - Insufficient amount of memory available.
 336  *
 337  * %-EINVAL - Invalid segment usage number.
 338  */
 339 int nilfs_sufile_get_segment_usage(struct inode *sufile, __u64 segnum,
 340                                    struct nilfs_segment_usage **sup,
 341                                    struct buffer_head **bhp)
 342 {
 343         struct buffer_head *bh;
 344         struct nilfs_segment_usage *su;
 345         void *kaddr;
 346         int ret;
 347
 348         /* segnum is 0 origin */
 349         if (segnum >= nilfs_sufile_get_nsegments(sufile))
 350                 return -EINVAL;
 351         down_write(&NILFS_MDT(sufile)->mi_sem);
 352         ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 1, &bh);
 353         if (ret < 0)
 354                 goto out_sem;
 355         kaddr = kmap(bh->b_page);
 356         su = nilfs_sufile_block_get_segment_usage(sufile, segnum, bh, kaddr);
 357         if (nilfs_segment_usage_error(su)) {
 358                 kunmap(bh->b_page);
 359                 brelse(bh);
 360                 ret = -EINVAL;
 361                 goto out_sem;
 362         }
 363
 364         if (sup != NULL)
 365                 *sup = su;
 366         *bhp = bh;
 367
 368  out_sem:
 369         up_write(&NILFS_MDT(sufile)->mi_sem);
 370         return ret;
 371 }
 372
 373 /**
 374  * nilfs_sufile_put_segment_usage - put a segment usage
 375  * @sufile: inode of segment usage file
 376  * @segnum: segment number
 377  * @bh: buffer head
 378  *
 379  * Description: nilfs_sufile_put_segment_usage() releases the segment usage
 380  * specified by @segnum. @bh must be the buffer head which have been returned
 381  * by a previous call to nilfs_sufile_get_segment_usage() with @segnum.
 382  */
 383 void nilfs_sufile_put_segment_usage(struct inode *sufile, __u64 segnum,
 384                                     struct buffer_head *bh)
 385 {
 386         kunmap(bh->b_page);
 387         brelse(bh);
 388 }
 389
 390 /**
 391  * nilfs_sufile_get_stat - get segment usage statistics
 392  * @sufile: inode of segment usage file
 393  * @stat: pointer to a structure of segment usage statistics
 394  *
 395  * Description: nilfs_sufile_get_stat() returns information about segment
 396  * usage.
 397  *
 398  * Return Value: On success, 0 is returned, and segment usage information is
 399  * stored in the place pointed by @stat. On error, one of the following
 400  * negative error codes is returned.
 401  *
 402  * %-EIO - I/O error.
 403  *
 404  * %-ENOMEM - Insufficient amount of memory available.
 405  */
 406 int nilfs_sufile_get_stat(struct inode *sufile, struct nilfs_sustat *sustat)
 407 {
 408         struct buffer_head *header_bh;
 409         struct nilfs_sufile_header *header;
 410         struct the_nilfs *nilfs = NILFS_MDT(sufile)->mi_nilfs;
 411         void *kaddr;
 412         int ret;
 413
 414         down_read(&NILFS_MDT(sufile)->mi_sem);
 415
 416         ret = nilfs_sufile_get_header_block(sufile, &header_bh);
 417         if (ret < 0)
 418                 goto out_sem;
 419
 420         kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
 421         header = nilfs_sufile_block_get_header(sufile, header_bh, kaddr);
 422         sustat->ss_nsegs = nilfs_sufile_get_nsegments(sufile);
 423         sustat->ss_ncleansegs = le64_to_cpu(header->sh_ncleansegs);
 424         sustat->ss_ndirtysegs = le64_to_cpu(header->sh_ndirtysegs);
 425         sustat->ss_ctime = nilfs->ns_ctime;
 426         sustat->ss_nongc_ctime = nilfs->ns_nongc_ctime;
 427         spin_lock(&nilfs->ns_last_segment_lock);
 428         sustat->ss_prot_seq = nilfs->ns_prot_seq;
 429         spin_unlock(&nilfs->ns_last_segment_lock);
 430         kunmap_atomic(kaddr, KM_USER0);
 431         brelse(header_bh);
 432
 433  out_sem:
 434         up_read(&NILFS_MDT(sufile)->mi_sem);
 435         return ret;
 436 }
 437
 438 /**
 439  * nilfs_sufile_get_ncleansegs - get the number of clean segments
 440  * @sufile: inode of segment usage file
 441  * @nsegsp: pointer to the number of clean segments
 442  *
 443  * Description: nilfs_sufile_get_ncleansegs() acquires the number of clean
 444  * segments.
 445  *
 446  * Return Value: On success, 0 is returned and the number of clean segments is
 447  * stored in the place pointed by @nsegsp. On error, one of the following
 448  * negative error codes is returned.
 449  *
 450  * %-EIO - I/O error.
 451  *
 452  * %-ENOMEM - Insufficient amount of memory available.
 453  */
 454 int nilfs_sufile_get_ncleansegs(struct inode *sufile, unsigned long *nsegsp)
 455 {
 456         struct nilfs_sustat sustat;
 457         int ret;
 458
 459         ret = nilfs_sufile_get_stat(sufile, &sustat);
 460         if (ret == 0)
 461                 *nsegsp = sustat.ss_ncleansegs;
 462         return ret;
 463 }
 464
 465 void nilfs_sufile_do_set_error(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 suclean;
 472
 473         kaddr = kmap_atomic(su_bh->b_page, KM_USER0);
 474         su = nilfs_sufile_block_get_segment_usage(sufile, segnum, su_bh, kaddr);
 475         if (nilfs_segment_usage_error(su)) {
 476                 kunmap_atomic(kaddr, KM_USER0);
 477                 return;
 478         }
 479         suclean = nilfs_segment_usage_clean(su);
 480         nilfs_segment_usage_set_error(su);
 481         kunmap_atomic(kaddr, KM_USER0);
 482
 483         if (suclean)
 484                 nilfs_sufile_mod_counter(header_bh, -1, 0);
 485         nilfs_mdt_mark_buffer_dirty(su_bh);
 486         nilfs_mdt_mark_dirty(sufile);
 487 }
 488
 489 /**
 490  * nilfs_sufile_get_suinfo -
 491  * @sufile: inode of segment usage file
 492  * @segnum: segment number to start looking
 493  * @si: array of suinfo
 494  * @nsi: size of suinfo array
 495  *
 496  * Description:
 497  *
 498  * Return Value: On success, 0 is returned and .... On error, one of the
 499  * following negative error codes is returned.
 500  *
 501  * %-EIO - I/O error.
 502  *
 503  * %-ENOMEM - Insufficient amount of memory available.
 504  */
 505 ssize_t nilfs_sufile_get_suinfo(struct inode *sufile, __u64 segnum,
 506                                 struct nilfs_suinfo *si, size_t nsi)
 507 {
 508         struct buffer_head *su_bh;
 509         struct nilfs_segment_usage *su;
 510         size_t susz = NILFS_MDT(sufile)->mi_entry_size;
 511         struct the_nilfs *nilfs = NILFS_MDT(sufile)->mi_nilfs;
 512         void *kaddr;
 513         unsigned long nsegs, segusages_per_block;
 514         ssize_t n;
 515         int ret, i, j;
 516
 517         down_read(&NILFS_MDT(sufile)->mi_sem);
 518
 519         segusages_per_block = nilfs_sufile_segment_usages_per_block(sufile);
 520         nsegs = min_t(unsigned long,
 521                       nilfs_sufile_get_nsegments(sufile) - segnum,
 522                       nsi);
 523         for (i = 0; i < nsegs; i += n, segnum += n) {
 524                 n = min_t(unsigned long,
 525                           segusages_per_block -
 526                                   nilfs_sufile_get_offset(sufile, segnum),
 527                           nsegs - i);
 528                 ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 0,
 529                                                            &su_bh);
 530                 if (ret < 0) {
 531                         if (ret != -ENOENT)
 532                                 goto out;
 533                         /* hole */
 534                         memset(&si[i], 0, sizeof(struct nilfs_suinfo) * n);
 535                         continue;
 536                 }
 537
 538                 kaddr = kmap_atomic(su_bh->b_page, KM_USER0);
 539                 su = nilfs_sufile_block_get_segment_usage(
 540                         sufile, segnum, su_bh, kaddr);
 541                 for (j = 0; j < n; j++, su = (void *)su + susz) {
 542                         si[i + j].sui_lastmod = le64_to_cpu(su->su_lastmod);
 543                         si[i + j].sui_nblocks = le32_to_cpu(su->su_nblocks);
 544                         si[i + j].sui_flags = le32_to_cpu(su->su_flags) &
 545                                 ~(1UL << NILFS_SEGMENT_USAGE_ACTIVE);
 546                         if (nilfs_segment_is_active(nilfs, segnum + j))
 547                                 si[i + j].sui_flags |=
 548                                         (1UL << NILFS_SEGMENT_USAGE_ACTIVE);
 549                 }
 550                 kunmap_atomic(kaddr, KM_USER0);
 551                 brelse(su_bh);
 552         }
 553         ret = nsegs;
 554
 555  out:
 556         up_read(&NILFS_MDT(sufile)->mi_sem);
 557         return ret;
 558 }