git.oblomov.eu Git - linux-2.6/blob - fs/nilfs2/the_nilfs.c

   1 /*
   2  * the_nilfs.c - the_nilfs shared structure.
   3  *
   4  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * 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 Ryusuke Konishi <ryusuke@osrg.net>
  21  *
  22  */
  23
  24 #include <linux/buffer_head.h>
  25 #include <linux/slab.h>
  26 #include <linux/blkdev.h>
  27 #include <linux/backing-dev.h>
  28 #include "nilfs.h"
  29 #include "segment.h"
  30 #include "alloc.h"
  31 #include "cpfile.h"
  32 #include "sufile.h"
  33 #include "dat.h"
  34 #include "seglist.h"
  35 #include "segbuf.h"
  36
  37 void nilfs_set_last_segment(struct the_nilfs *nilfs,
  38                             sector_t start_blocknr, u64 seq, __u64 cno)
  39 {
  40         spin_lock(&nilfs->ns_last_segment_lock);
  41         nilfs->ns_last_pseg = start_blocknr;
  42         nilfs->ns_last_seq = seq;
  43         nilfs->ns_last_cno = cno;
  44         spin_unlock(&nilfs->ns_last_segment_lock);
  45 }
  46
  47 /**
  48  * alloc_nilfs - allocate the_nilfs structure
  49  * @bdev: block device to which the_nilfs is related
  50  *
  51  * alloc_nilfs() allocates memory for the_nilfs and
  52  * initializes its reference count and locks.
  53  *
  54  * Return Value: On success, pointer to the_nilfs is returned.
  55  * On error, NULL is returned.
  56  */
  57 struct the_nilfs *alloc_nilfs(struct block_device *bdev)
  58 {
  59         struct the_nilfs *nilfs;
  60
  61         nilfs = kzalloc(sizeof(*nilfs), GFP_KERNEL);
  62         if (!nilfs)
  63                 return NULL;
  64
  65         nilfs->ns_bdev = bdev;
  66         atomic_set(&nilfs->ns_count, 1);
  67         atomic_set(&nilfs->ns_writer_refcount, -1);
  68         atomic_set(&nilfs->ns_ndirtyblks, 0);
  69         init_rwsem(&nilfs->ns_sem);
  70         mutex_init(&nilfs->ns_writer_mutex);
  71         INIT_LIST_HEAD(&nilfs->ns_supers);
  72         spin_lock_init(&nilfs->ns_last_segment_lock);
  73         nilfs->ns_gc_inodes_h = NULL;
  74         INIT_LIST_HEAD(&nilfs->ns_used_segments);
  75         init_rwsem(&nilfs->ns_segctor_sem);
  76         init_waitqueue_head(&nilfs->ns_cleanerd_wq);
  77
  78         return nilfs;
  79 }
  80
  81 /**
  82  * put_nilfs - release a reference to the_nilfs
  83  * @nilfs: the_nilfs structure to be released
  84  *
  85  * put_nilfs() decrements a reference counter of the_nilfs.
  86  * If the reference count reaches zero, the_nilfs is freed.
  87  */
  88 void put_nilfs(struct the_nilfs *nilfs)
  89 {
  90         if (!atomic_dec_and_test(&nilfs->ns_count))
  91                 return;
  92         /*
  93          * Increment of ns_count never occur below because the caller
  94          * of get_nilfs() holds at least one reference to the_nilfs.
  95          * Thus its exclusion control is not required here.
  96          */
  97         might_sleep();
  98         if (nilfs_loaded(nilfs)) {
  99                 nilfs_dispose_used_segments(nilfs);
 100                 nilfs_mdt_clear(nilfs->ns_sufile);
 101                 nilfs_mdt_destroy(nilfs->ns_sufile);
 102                 nilfs_mdt_clear(nilfs->ns_cpfile);
 103                 nilfs_mdt_destroy(nilfs->ns_cpfile);
 104                 nilfs_mdt_clear(nilfs->ns_dat);
 105                 nilfs_mdt_destroy(nilfs->ns_dat);
 106                 /* XXX: how and when to clear nilfs->ns_gc_dat? */
 107                 nilfs_mdt_destroy(nilfs->ns_gc_dat);
 108         }
 109         if (nilfs_init(nilfs)) {
 110                 nilfs_destroy_gccache(nilfs);
 111                 brelse(nilfs->ns_sbh);
 112         }
 113         kfree(nilfs);
 114 }
 115
 116 static int nilfs_load_super_root(struct the_nilfs *nilfs,
 117                                  struct nilfs_sb_info *sbi, sector_t sr_block)
 118 {
 119         struct buffer_head *bh_sr;
 120         struct nilfs_super_root *raw_sr;
 121         unsigned dat_entry_size, segment_usage_size, checkpoint_size;
 122         unsigned inode_size;
 123         int err;
 124
 125         err = nilfs_read_super_root_block(sbi->s_super, sr_block, &bh_sr, 1);
 126         if (unlikely(err))
 127                 return err;
 128
 129         down_read(&nilfs->ns_sem);
 130         dat_entry_size = le16_to_cpu(nilfs->ns_sbp->s_dat_entry_size);
 131         checkpoint_size = le16_to_cpu(nilfs->ns_sbp->s_checkpoint_size);
 132         segment_usage_size = le16_to_cpu(nilfs->ns_sbp->s_segment_usage_size);
 133         up_read(&nilfs->ns_sem);
 134
 135         inode_size = nilfs->ns_inode_size;
 136
 137         err = -ENOMEM;
 138         nilfs->ns_dat = nilfs_mdt_new(
 139                 nilfs, NULL, NILFS_DAT_INO, NILFS_DAT_GFP);
 140         if (unlikely(!nilfs->ns_dat))
 141                 goto failed;
 142
 143         nilfs->ns_gc_dat = nilfs_mdt_new(
 144                 nilfs, NULL, NILFS_DAT_INO, NILFS_DAT_GFP);
 145         if (unlikely(!nilfs->ns_gc_dat))
 146                 goto failed_dat;
 147
 148         nilfs->ns_cpfile = nilfs_mdt_new(
 149                 nilfs, NULL, NILFS_CPFILE_INO, NILFS_CPFILE_GFP);
 150         if (unlikely(!nilfs->ns_cpfile))
 151                 goto failed_gc_dat;
 152
 153         nilfs->ns_sufile = nilfs_mdt_new(
 154                 nilfs, NULL, NILFS_SUFILE_INO, NILFS_SUFILE_GFP);
 155         if (unlikely(!nilfs->ns_sufile))
 156                 goto failed_cpfile;
 157
 158         err = nilfs_palloc_init_blockgroup(nilfs->ns_dat, dat_entry_size);
 159         if (unlikely(err))
 160                 goto failed_sufile;
 161
 162         err = nilfs_palloc_init_blockgroup(nilfs->ns_gc_dat, dat_entry_size);
 163         if (unlikely(err))
 164                 goto failed_sufile;
 165
 166         nilfs_mdt_set_shadow(nilfs->ns_dat, nilfs->ns_gc_dat);
 167         nilfs_mdt_set_entry_size(nilfs->ns_cpfile, checkpoint_size,
 168                                  sizeof(struct nilfs_cpfile_header));
 169         nilfs_mdt_set_entry_size(nilfs->ns_sufile, segment_usage_size,
 170                                  sizeof(struct nilfs_sufile_header));
 171
 172         err = nilfs_mdt_read_inode_direct(
 173                 nilfs->ns_dat, bh_sr, NILFS_SR_DAT_OFFSET(inode_size));
 174         if (unlikely(err))
 175                 goto failed_sufile;
 176
 177         err = nilfs_mdt_read_inode_direct(
 178                 nilfs->ns_cpfile, bh_sr, NILFS_SR_CPFILE_OFFSET(inode_size));
 179         if (unlikely(err))
 180                 goto failed_sufile;
 181
 182         err = nilfs_mdt_read_inode_direct(
 183                 nilfs->ns_sufile, bh_sr, NILFS_SR_SUFILE_OFFSET(inode_size));
 184         if (unlikely(err))
 185                 goto failed_sufile;
 186
 187         raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
 188         nilfs->ns_nongc_ctime = le64_to_cpu(raw_sr->sr_nongc_ctime);
 189
 190  failed:
 191         brelse(bh_sr);
 192         return err;
 193
 194  failed_sufile:
 195         nilfs_mdt_destroy(nilfs->ns_sufile);
 196
 197  failed_cpfile:
 198         nilfs_mdt_destroy(nilfs->ns_cpfile);
 199
 200  failed_gc_dat:
 201         nilfs_mdt_destroy(nilfs->ns_gc_dat);
 202
 203  failed_dat:
 204         nilfs_mdt_destroy(nilfs->ns_dat);
 205         goto failed;
 206 }
 207
 208 static void nilfs_init_recovery_info(struct nilfs_recovery_info *ri)
 209 {
 210         memset(ri, 0, sizeof(*ri));
 211         INIT_LIST_HEAD(&ri->ri_used_segments);
 212 }
 213
 214 static void nilfs_clear_recovery_info(struct nilfs_recovery_info *ri)
 215 {
 216         nilfs_dispose_segment_list(&ri->ri_used_segments);
 217 }
 218
 219 /**
 220  * load_nilfs - load and recover the nilfs
 221  * @nilfs: the_nilfs structure to be released
 222  * @sbi: nilfs_sb_info used to recover past segment
 223  *
 224  * load_nilfs() searches and load the latest super root,
 225  * attaches the last segment, and does recovery if needed.
 226  * The caller must call this exclusively for simultaneous mounts.
 227  */
 228 int load_nilfs(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi)
 229 {
 230         struct nilfs_recovery_info ri;
 231         unsigned int s_flags = sbi->s_super->s_flags;
 232         int really_read_only = bdev_read_only(nilfs->ns_bdev);
 233         unsigned valid_fs;
 234         int err = 0;
 235
 236         nilfs_init_recovery_info(&ri);
 237
 238         down_write(&nilfs->ns_sem);
 239         valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS);
 240         up_write(&nilfs->ns_sem);
 241
 242         if (!valid_fs && (s_flags & MS_RDONLY)) {
 243                 printk(KERN_INFO "NILFS: INFO: recovery "
 244                        "required for readonly filesystem.\n");
 245                 if (really_read_only) {
 246                         printk(KERN_ERR "NILFS: write access "
 247                                "unavailable, cannot proceed.\n");
 248                         err = -EROFS;
 249                         goto failed;
 250                 }
 251                 printk(KERN_INFO "NILFS: write access will "
 252                        "be enabled during recovery.\n");
 253                 sbi->s_super->s_flags &= ~MS_RDONLY;
 254         }
 255
 256         err = nilfs_search_super_root(nilfs, sbi, &ri);
 257         if (unlikely(err)) {
 258                 printk(KERN_ERR "NILFS: error searching super root.\n");
 259                 goto failed;
 260         }
 261
 262         err = nilfs_load_super_root(nilfs, sbi, ri.ri_super_root);
 263         if (unlikely(err)) {
 264                 printk(KERN_ERR "NILFS: error loading super root.\n");
 265                 goto failed;
 266         }
 267
 268         if (!valid_fs) {
 269                 err = nilfs_recover_logical_segments(nilfs, sbi, &ri);
 270                 if (unlikely(err)) {
 271                         nilfs_mdt_destroy(nilfs->ns_cpfile);
 272                         nilfs_mdt_destroy(nilfs->ns_sufile);
 273                         nilfs_mdt_destroy(nilfs->ns_dat);
 274                         goto failed;
 275                 }
 276                 if (ri.ri_need_recovery == NILFS_RECOVERY_SR_UPDATED) {
 277                         down_write(&nilfs->ns_sem);
 278                         nilfs_update_last_segment(sbi, 0);
 279                         up_write(&nilfs->ns_sem);
 280                 }
 281         }
 282
 283         set_nilfs_loaded(nilfs);
 284
 285  failed:
 286         nilfs_clear_recovery_info(&ri);
 287         sbi->s_super->s_flags = s_flags;
 288         return err;
 289 }
 290
 291 static unsigned long long nilfs_max_size(unsigned int blkbits)
 292 {
 293         unsigned int max_bits;
 294         unsigned long long res = MAX_LFS_FILESIZE; /* page cache limit */
 295
 296         max_bits = blkbits + NILFS_BMAP_KEY_BIT; /* bmap size limit */
 297         if (max_bits < 64)
 298                 res = min_t(unsigned long long, res, (1ULL << max_bits) - 1);
 299         return res;
 300 }
 301
 302 static int
 303 nilfs_store_disk_layout(struct the_nilfs *nilfs, struct super_block *sb,
 304                         struct nilfs_super_block *sbp)
 305 {
 306         if (le32_to_cpu(sbp->s_rev_level) != NILFS_CURRENT_REV) {
 307                 printk(KERN_ERR "NILFS: revision mismatch "
 308                        "(superblock rev.=%d.%d, current rev.=%d.%d). "
 309                        "Please check the version of mkfs.nilfs.\n",
 310                        le32_to_cpu(sbp->s_rev_level),
 311                        le16_to_cpu(sbp->s_minor_rev_level),
 312                        NILFS_CURRENT_REV, NILFS_MINOR_REV);
 313                 return -EINVAL;
 314         }
 315         nilfs->ns_inode_size = le16_to_cpu(sbp->s_inode_size);
 316         nilfs->ns_first_ino = le32_to_cpu(sbp->s_first_ino);
 317
 318         nilfs->ns_blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment);
 319         if (nilfs->ns_blocks_per_segment < NILFS_SEG_MIN_BLOCKS) {
 320                 printk(KERN_ERR "NILFS: too short segment. \n");
 321                 return -EINVAL;
 322         }
 323
 324         nilfs->ns_first_data_block = le64_to_cpu(sbp->s_first_data_block);
 325         nilfs->ns_nsegments = le64_to_cpu(sbp->s_nsegments);
 326         nilfs->ns_r_segments_percentage =
 327                 le32_to_cpu(sbp->s_r_segments_percentage);
 328         nilfs->ns_nrsvsegs =
 329                 max_t(unsigned long, NILFS_MIN_NRSVSEGS,
 330                       DIV_ROUND_UP(nilfs->ns_nsegments *
 331                                    nilfs->ns_r_segments_percentage, 100));
 332         nilfs->ns_crc_seed = le32_to_cpu(sbp->s_crc_seed);
 333         return 0;
 334 }
 335
 336 /**
 337  * init_nilfs - initialize a NILFS instance.
 338  * @nilfs: the_nilfs structure
 339  * @sbi: nilfs_sb_info
 340  * @sb: super block
 341  * @data: mount options
 342  *
 343  * init_nilfs() performs common initialization per block device (e.g.
 344  * reading the super block, getting disk layout information, initializing
 345  * shared fields in the_nilfs). It takes on some portion of the jobs
 346  * typically done by a fill_super() routine. This division arises from
 347  * the nature that multiple NILFS instances may be simultaneously
 348  * mounted on a device.
 349  * For multiple mounts on the same device, only the first mount
 350  * invokes these tasks.
 351  *
 352  * Return Value: On success, 0 is returned. On error, a negative error
 353  * code is returned.
 354  */
 355 int init_nilfs(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi, char *data)
 356 {
 357         struct super_block *sb = sbi->s_super;
 358         struct buffer_head *sbh;
 359         struct nilfs_super_block *sbp;
 360         struct backing_dev_info *bdi;
 361         int blocksize;
 362         int err = 0;
 363
 364         down_write(&nilfs->ns_sem);
 365         if (nilfs_init(nilfs)) {
 366                 /* Load values from existing the_nilfs */
 367                 sbp = nilfs->ns_sbp;
 368                 err = nilfs_store_magic_and_option(sb, sbp, data);
 369                 if (err)
 370                         goto out;
 371
 372                 blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
 373                 if (sb->s_blocksize != blocksize &&
 374                     !sb_set_blocksize(sb, blocksize)) {
 375                         printk(KERN_ERR "NILFS: blocksize %d unfit to device\n",
 376                                blocksize);
 377                         err = -EINVAL;
 378                 }
 379                 sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits);
 380                 goto out;
 381         }
 382
 383         sbp = nilfs_load_super_block(sb, &sbh);
 384         if (!sbp) {
 385                 err = -EINVAL;
 386                 goto out;
 387         }
 388         err = nilfs_store_magic_and_option(sb, sbp, data);
 389         if (err)
 390                 goto failed_sbh;
 391
 392         blocksize = BLOCK_SIZE << le32_to_cpu(sbp->s_log_block_size);
 393         if (sb->s_blocksize != blocksize) {
 394                 sbp = nilfs_reload_super_block(sb, &sbh, blocksize);
 395                 if (!sbp) {
 396                         err = -EINVAL;
 397                         goto out;
 398                         /* not failed_sbh; sbh is released automatically
 399                            when reloading fails. */
 400                 }
 401         }
 402         nilfs->ns_blocksize_bits = sb->s_blocksize_bits;
 403
 404         err = nilfs_store_disk_layout(nilfs, sb, sbp);
 405         if (err)
 406                 goto failed_sbh;
 407
 408         sb->s_maxbytes = nilfs_max_size(sb->s_blocksize_bits);
 409
 410         nilfs->ns_mount_state = le16_to_cpu(sbp->s_state);
 411         nilfs->ns_sbh = sbh;
 412         nilfs->ns_sbp = sbp;
 413
 414         bdi = nilfs->ns_bdev->bd_inode_backing_dev_info;
 415         if (!bdi)
 416                 bdi = nilfs->ns_bdev->bd_inode->i_mapping->backing_dev_info;
 417         nilfs->ns_bdi = bdi ? : &default_backing_dev_info;
 418
 419         /* Finding last segment */
 420         nilfs->ns_last_pseg = le64_to_cpu(sbp->s_last_pseg);
 421         nilfs->ns_last_cno = le64_to_cpu(sbp->s_last_cno);
 422         nilfs->ns_last_seq = le64_to_cpu(sbp->s_last_seq);
 423
 424         nilfs->ns_seg_seq = nilfs->ns_last_seq;
 425         nilfs->ns_segnum =
 426                 nilfs_get_segnum_of_block(nilfs, nilfs->ns_last_pseg);
 427         nilfs->ns_cno = nilfs->ns_last_cno + 1;
 428         if (nilfs->ns_segnum >= nilfs->ns_nsegments) {
 429                 printk(KERN_ERR "NILFS invalid last segment number.\n");
 430                 err = -EINVAL;
 431                 goto failed_sbh;
 432         }
 433         /* Dummy values  */
 434         nilfs->ns_free_segments_count =
 435                 nilfs->ns_nsegments - (nilfs->ns_segnum + 1);
 436
 437         /* Initialize gcinode cache */
 438         err = nilfs_init_gccache(nilfs);
 439         if (err)
 440                 goto failed_sbh;
 441
 442         set_nilfs_init(nilfs);
 443         err = 0;
 444  out:
 445         up_write(&nilfs->ns_sem);
 446         return err;
 447
 448  failed_sbh:
 449         brelse(sbh);
 450         goto out;
 451 }
 452
 453 int nilfs_count_free_blocks(struct the_nilfs *nilfs, sector_t *nblocks)
 454 {
 455         struct inode *dat = nilfs_dat_inode(nilfs);
 456         unsigned long ncleansegs;
 457         int err;
 458
 459         down_read(&NILFS_MDT(dat)->mi_sem);     /* XXX */
 460         err = nilfs_sufile_get_ncleansegs(nilfs->ns_sufile, &ncleansegs);
 461         up_read(&NILFS_MDT(dat)->mi_sem);       /* XXX */
 462         if (likely(!err))
 463                 *nblocks = (sector_t)ncleansegs * nilfs->ns_blocks_per_segment;
 464         return err;
 465 }
 466
 467 void nilfs_dispose_used_segments(struct the_nilfs *nilfs)
 468 {
 469         struct nilfs_segment_entry *ent, *n;
 470
 471         /* nilfs->sem must be locked by the caller. */
 472         if (!nilfs_loaded(nilfs))
 473                 return;
 474
 475         list_for_each_entry_safe(ent, n, &nilfs->ns_used_segments, list) {
 476                 list_del_init(&ent->list);
 477                 nilfs_segment_usage_clear_volatile_active(ent->raw_su);
 478                 nilfs_close_segment_entry(ent, nilfs->ns_sufile);
 479                 nilfs_free_segment_entry(ent);
 480         }
 481 }
 482
 483 int nilfs_near_disk_full(struct the_nilfs *nilfs)
 484 {
 485         struct inode *sufile = nilfs->ns_sufile;
 486         unsigned long ncleansegs, nincsegs;
 487         int ret;
 488
 489         ret = nilfs_sufile_get_ncleansegs(sufile, &ncleansegs);
 490         if (likely(!ret)) {
 491                 nincsegs = atomic_read(&nilfs->ns_ndirtyblks) /
 492                         nilfs->ns_blocks_per_segment + 1;
 493                 if (ncleansegs <= nilfs->ns_nrsvsegs + nincsegs)
 494                         ret++;
 495         }
 496         return ret;
 497 }
 498
 499 int nilfs_checkpoint_is_mounted(struct the_nilfs *nilfs, __u64 cno,
 500                                 int snapshot_mount)
 501 {
 502         struct nilfs_sb_info *sbi;
 503         int ret = 0;
 504
 505         down_read(&nilfs->ns_sem);
 506         if (cno == 0 || cno > nilfs->ns_cno)
 507                 goto out_unlock;
 508
 509         list_for_each_entry(sbi, &nilfs->ns_supers, s_list) {
 510                 if (sbi->s_snapshot_cno == cno &&
 511                     (!snapshot_mount || nilfs_test_opt(sbi, SNAPSHOT))) {
 512                                         /* exclude read-only mounts */
 513                         ret++;
 514                         break;
 515                 }
 516         }
 517         /* for protecting recent checkpoints */
 518         if (cno >= nilfs_last_cno(nilfs))
 519                 ret++;
 520
 521  out_unlock:
 522         up_read(&nilfs->ns_sem);
 523         return ret;
 524 }