fs/nilfs2/super.c

   1 /*
   2  * super.c - NILFS module and super block management.
   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  *  linux/fs/ext2/super.c
  24  *
  25  * Copyright (C) 1992, 1993, 1994, 1995
  26  * Remy Card (card@masi.ibp.fr)
  27  * Laboratoire MASI - Institut Blaise Pascal
  28  * Universite Pierre et Marie Curie (Paris VI)
  29  *
  30  *  from
  31  *
  32  *  linux/fs/minix/inode.c
  33  *
  34  *  Copyright (C) 1991, 1992  Linus Torvalds
  35  *
  36  *  Big-endian to little-endian byte-swapping/bitmaps by
  37  *        David S. Miller (davem@caip.rutgers.edu), 1995
  38  */
  39
  40 #include <linux/module.h>
  41 #include <linux/string.h>
  42 #include <linux/slab.h>
  43 #include <linux/init.h>
  44 #include <linux/blkdev.h>
  45 #include <linux/parser.h>
  46 #include <linux/random.h>
  47 #include <linux/crc32.h>
  48 #include <linux/smp_lock.h>
  49 #include <linux/vfs.h>
  50 #include <linux/writeback.h>
  51 #include <linux/kobject.h>
  52 #include <linux/exportfs.h>
  53 #include <linux/seq_file.h>
  54 #include <linux/mount.h>
  55 #include "nilfs.h"
  56 #include "mdt.h"
  57 #include "alloc.h"
  58 #include "page.h"
  59 #include "cpfile.h"
  60 #include "ifile.h"
  61 #include "dat.h"
  62 #include "segment.h"
  63 #include "segbuf.h"
  64
  65 MODULE_AUTHOR("NTT Corp.");
  66 MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
  67                    "(NILFS)");
  68 MODULE_LICENSE("GPL");
  69
  70 struct kmem_cache *nilfs_inode_cachep;
  71 struct kmem_cache *nilfs_transaction_cachep;
  72 struct kmem_cache *nilfs_segbuf_cachep;
  73 struct kmem_cache *nilfs_btree_path_cache;
  74
  75 static int nilfs_remount(struct super_block *sb, int *flags, char *data);
  76
  77 /**
  78  * nilfs_error() - report failure condition on a filesystem
  79  *
  80  * nilfs_error() sets an ERROR_FS flag on the superblock as well as
  81  * reporting an error message.  It should be called when NILFS detects
  82  * incoherences or defects of meta data on disk.  As for sustainable
  83  * errors such as a single-shot I/O error, nilfs_warning() or the printk()
  84  * function should be used instead.
  85  *
  86  * The segment constructor must not call this function because it can
  87  * kill itself.
  88  */
  89 void nilfs_error(struct super_block *sb, const char *function,
  90                  const char *fmt, ...)
  91 {
  92         struct nilfs_sb_info *sbi = NILFS_SB(sb);
  93         va_list args;
  94
  95         va_start(args, fmt);
  96         printk(KERN_CRIT "NILFS error (device %s): %s: ", sb->s_id, function);
  97         vprintk(fmt, args);
  98         printk("\n");
  99         va_end(args);
 100
 101         if (!(sb->s_flags & MS_RDONLY)) {
 102                 struct the_nilfs *nilfs = sbi->s_nilfs;
 103
 104                 down_write(&nilfs->ns_sem);
 105                 if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
 106                         nilfs->ns_mount_state |= NILFS_ERROR_FS;
 107                         nilfs->ns_sbp[0]->s_state |=
 108                                 cpu_to_le16(NILFS_ERROR_FS);
 109                         nilfs_commit_super(sbi, 1);
 110                 }
 111                 up_write(&nilfs->ns_sem);
 112
 113                 if (nilfs_test_opt(sbi, ERRORS_RO)) {
 114                         printk(KERN_CRIT "Remounting filesystem read-only\n");
 115                         sb->s_flags |= MS_RDONLY;
 116                 }
 117         }
 118
 119         if (nilfs_test_opt(sbi, ERRORS_PANIC))
 120                 panic("NILFS (device %s): panic forced after error\n",
 121                       sb->s_id);
 122 }
 123
 124 void nilfs_warning(struct super_block *sb, const char *function,
 125                    const char *fmt, ...)
 126 {
 127         va_list args;
 128
 129         va_start(args, fmt);
 130         printk(KERN_WARNING "NILFS warning (device %s): %s: ",
 131                sb->s_id, function);
 132         vprintk(fmt, args);
 133         printk("\n");
 134         va_end(args);
 135 }
 136
 137
 138 struct inode *nilfs_alloc_inode_common(struct the_nilfs *nilfs)
 139 {
 140         struct nilfs_inode_info *ii;
 141
 142         ii = kmem_cache_alloc(nilfs_inode_cachep, GFP_NOFS);
 143         if (!ii)
 144                 return NULL;
 145         ii->i_bh = NULL;
 146         ii->i_state = 0;
 147         ii->vfs_inode.i_version = 1;
 148         nilfs_btnode_cache_init(&ii->i_btnode_cache, nilfs->ns_bdi);
 149         return &ii->vfs_inode;
 150 }
 151
 152 struct inode *nilfs_alloc_inode(struct super_block *sb)
 153 {
 154         return nilfs_alloc_inode_common(NILFS_SB(sb)->s_nilfs);
 155 }
 156
 157 void nilfs_destroy_inode(struct inode *inode)
 158 {
 159         kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
 160 }
 161
 162 static void nilfs_clear_inode(struct inode *inode)
 163 {
 164         struct nilfs_inode_info *ii = NILFS_I(inode);
 165
 166         /*
 167          * Free resources allocated in nilfs_read_inode(), here.
 168          */
 169         BUG_ON(!list_empty(&ii->i_dirty));
 170         brelse(ii->i_bh);
 171         ii->i_bh = NULL;
 172
 173         if (test_bit(NILFS_I_BMAP, &ii->i_state))
 174                 nilfs_bmap_clear(ii->i_bmap);
 175
 176         nilfs_btnode_cache_clear(&ii->i_btnode_cache);
 177 }
 178
 179 static int nilfs_sync_super(struct nilfs_sb_info *sbi, int dupsb)
 180 {
 181         struct the_nilfs *nilfs = sbi->s_nilfs;
 182         int err;
 183         int barrier_done = 0;
 184
 185         if (nilfs_test_opt(sbi, BARRIER)) {
 186                 set_buffer_ordered(nilfs->ns_sbh[0]);
 187                 barrier_done = 1;
 188         }
 189  retry:
 190         set_buffer_dirty(nilfs->ns_sbh[0]);
 191         err = sync_dirty_buffer(nilfs->ns_sbh[0]);
 192         if (err == -EOPNOTSUPP && barrier_done) {
 193                 nilfs_warning(sbi->s_super, __func__,
 194                               "barrier-based sync failed. "
 195                               "disabling barriers\n");
 196                 nilfs_clear_opt(sbi, BARRIER);
 197                 barrier_done = 0;
 198                 clear_buffer_ordered(nilfs->ns_sbh[0]);
 199                 goto retry;
 200         }
 201         if (unlikely(err)) {
 202                 printk(KERN_ERR
 203                        "NILFS: unable to write superblock (err=%d)\n", err);
 204                 if (err == -EIO && nilfs->ns_sbh[1]) {
 205                         nilfs_fall_back_super_block(nilfs);
 206                         goto retry;
 207                 }
 208         } else {
 209                 struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
 210
 211                 /*
 212                  * The latest segment becomes trailable from the position
 213                  * written in superblock.
 214                  */
 215                 clear_nilfs_discontinued(nilfs);
 216
 217                 /* update GC protection for recent segments */
 218                 if (nilfs->ns_sbh[1]) {
 219                         sbp = NULL;
 220                         if (dupsb) {
 221                                 set_buffer_dirty(nilfs->ns_sbh[1]);
 222                                 if (!sync_dirty_buffer(nilfs->ns_sbh[1]))
 223                                         sbp = nilfs->ns_sbp[1];
 224                         }
 225                 }
 226                 if (sbp) {
 227                         spin_lock(&nilfs->ns_last_segment_lock);
 228                         nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
 229                         spin_unlock(&nilfs->ns_last_segment_lock);
 230                 }
 231         }
 232
 233         return err;
 234 }
 235
 236 int nilfs_commit_super(struct nilfs_sb_info *sbi, int dupsb)
 237 {
 238         struct the_nilfs *nilfs = sbi->s_nilfs;
 239         struct nilfs_super_block **sbp = nilfs->ns_sbp;
 240         sector_t nfreeblocks;
 241         time_t t;
 242         int err;
 243
 244         /* nilfs->sem must be locked by the caller. */
 245         if (sbp[0]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 246                 if (sbp[1] && sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC))
 247                         nilfs_swap_super_block(nilfs);
 248                 else {
 249                         printk(KERN_CRIT "NILFS: superblock broke on dev %s\n",
 250                                sbi->s_super->s_id);
 251                         return -EIO;
 252                 }
 253         }
 254         err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
 255         if (unlikely(err)) {
 256                 printk(KERN_ERR "NILFS: failed to count free blocks\n");
 257                 return err;
 258         }
 259         spin_lock(&nilfs->ns_last_segment_lock);
 260         sbp[0]->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
 261         sbp[0]->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
 262         sbp[0]->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
 263         spin_unlock(&nilfs->ns_last_segment_lock);
 264
 265         t = get_seconds();
 266         nilfs->ns_sbwtime[0] = t;
 267         sbp[0]->s_free_blocks_count = cpu_to_le64(nfreeblocks);
 268         sbp[0]->s_wtime = cpu_to_le64(t);
 269         sbp[0]->s_sum = 0;
 270         sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 271                                              (unsigned char *)sbp[0],
 272                                              nilfs->ns_sbsize));
 273         if (dupsb && sbp[1]) {
 274                 memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 275                 nilfs->ns_sbwtime[1] = t;
 276         }
 277         clear_nilfs_sb_dirty(nilfs);
 278         return nilfs_sync_super(sbi, dupsb);
 279 }
 280
 281 static void nilfs_put_super(struct super_block *sb)
 282 {
 283         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 284         struct the_nilfs *nilfs = sbi->s_nilfs;
 285
 286         lock_kernel();
 287
 288         nilfs_detach_segment_constructor(sbi);
 289
 290         if (!(sb->s_flags & MS_RDONLY)) {
 291                 down_write(&nilfs->ns_sem);
 292                 nilfs->ns_sbp[0]->s_state = cpu_to_le16(nilfs->ns_mount_state);
 293                 nilfs_commit_super(sbi, 1);
 294                 up_write(&nilfs->ns_sem);
 295         }
 296         down_write(&nilfs->ns_super_sem);
 297         if (nilfs->ns_current == sbi)
 298                 nilfs->ns_current = NULL;
 299         up_write(&nilfs->ns_super_sem);
 300
 301         nilfs_detach_checkpoint(sbi);
 302         put_nilfs(sbi->s_nilfs);
 303         sbi->s_super = NULL;
 304         sb->s_fs_info = NULL;
 305         nilfs_put_sbinfo(sbi);
 306
 307         unlock_kernel();
 308 }
 309
 310 static int nilfs_sync_fs(struct super_block *sb, int wait)
 311 {
 312         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 313         struct the_nilfs *nilfs = sbi->s_nilfs;
 314         int err = 0;
 315
 316         /* This function is called when super block should be written back */
 317         if (wait)
 318                 err = nilfs_construct_segment(sb);
 319
 320         down_write(&nilfs->ns_sem);
 321         if (nilfs_sb_dirty(nilfs))
 322                 nilfs_commit_super(sbi, 1);
 323         up_write(&nilfs->ns_sem);
 324
 325         return err;
 326 }
 327
 328 int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno)
 329 {
 330         struct the_nilfs *nilfs = sbi->s_nilfs;
 331         struct nilfs_checkpoint *raw_cp;
 332         struct buffer_head *bh_cp;
 333         int err;
 334
 335         down_write(&nilfs->ns_super_sem);
 336         list_add(&sbi->s_list, &nilfs->ns_supers);
 337         up_write(&nilfs->ns_super_sem);
 338
 339         sbi->s_ifile = nilfs_ifile_new(sbi, nilfs->ns_inode_size);
 340         if (!sbi->s_ifile)
 341                 return -ENOMEM;
 342
 343         down_read(&nilfs->ns_segctor_sem);
 344         err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
 345                                           &bh_cp);
 346         up_read(&nilfs->ns_segctor_sem);
 347         if (unlikely(err)) {
 348                 if (err == -ENOENT || err == -EINVAL) {
 349                         printk(KERN_ERR
 350                                "NILFS: Invalid checkpoint "
 351                                "(checkpoint number=%llu)\n",
 352                                (unsigned long long)cno);
 353                         err = -EINVAL;
 354                 }
 355                 goto failed;
 356         }
 357         err = nilfs_read_inode_common(sbi->s_ifile, &raw_cp->cp_ifile_inode);
 358         if (unlikely(err))
 359                 goto failed_bh;
 360         atomic_set(&sbi->s_inodes_count, le64_to_cpu(raw_cp->cp_inodes_count));
 361         atomic_set(&sbi->s_blocks_count, le64_to_cpu(raw_cp->cp_blocks_count));
 362
 363         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 364         return 0;
 365
 366  failed_bh:
 367         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 368  failed:
 369         nilfs_mdt_destroy(sbi->s_ifile);
 370         sbi->s_ifile = NULL;
 371
 372         down_write(&nilfs->ns_super_sem);
 373         list_del_init(&sbi->s_list);
 374         up_write(&nilfs->ns_super_sem);
 375
 376         return err;
 377 }
 378
 379 void nilfs_detach_checkpoint(struct nilfs_sb_info *sbi)
 380 {
 381         struct the_nilfs *nilfs = sbi->s_nilfs;
 382
 383         nilfs_mdt_destroy(sbi->s_ifile);
 384         sbi->s_ifile = NULL;
 385         down_write(&nilfs->ns_super_sem);
 386         list_del_init(&sbi->s_list);
 387         up_write(&nilfs->ns_super_sem);
 388 }
 389
 390 static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 391 {
 392         struct super_block *sb = dentry->d_sb;
 393         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 394         struct the_nilfs *nilfs = sbi->s_nilfs;
 395         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 396         unsigned long long blocks;
 397         unsigned long overhead;
 398         unsigned long nrsvblocks;
 399         sector_t nfreeblocks;
 400         int err;
 401
 402         /*
 403          * Compute all of the segment blocks
 404          *
 405          * The blocks before first segment and after last segment
 406          * are excluded.
 407          */
 408         blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
 409                 - nilfs->ns_first_data_block;
 410         nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
 411
 412         /*
 413          * Compute the overhead
 414          *
 415          * When distributing meta data blocks outside segment structure,
 416          * We must count them as the overhead.
 417          */
 418         overhead = 0;
 419
 420         err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
 421         if (unlikely(err))
 422                 return err;
 423
 424         buf->f_type = NILFS_SUPER_MAGIC;
 425         buf->f_bsize = sb->s_blocksize;
 426         buf->f_blocks = blocks - overhead;
 427         buf->f_bfree = nfreeblocks;
 428         buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
 429                 (buf->f_bfree - nrsvblocks) : 0;
 430         buf->f_files = atomic_read(&sbi->s_inodes_count);
 431         buf->f_ffree = 0; /* nilfs_count_free_inodes(sb); */
 432         buf->f_namelen = NILFS_NAME_LEN;
 433         buf->f_fsid.val[0] = (u32)id;
 434         buf->f_fsid.val[1] = (u32)(id >> 32);
 435
 436         return 0;
 437 }
 438
 439 static int nilfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
 440 {
 441         struct super_block *sb = vfs->mnt_sb;
 442         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 443
 444         if (!nilfs_test_opt(sbi, BARRIER))
 445                 seq_printf(seq, ",nobarrier");
 446         if (nilfs_test_opt(sbi, SNAPSHOT))
 447                 seq_printf(seq, ",cp=%llu",
 448                            (unsigned long long int)sbi->s_snapshot_cno);
 449         if (nilfs_test_opt(sbi, ERRORS_PANIC))
 450                 seq_printf(seq, ",errors=panic");
 451         if (nilfs_test_opt(sbi, ERRORS_CONT))
 452                 seq_printf(seq, ",errors=continue");
 453         if (nilfs_test_opt(sbi, STRICT_ORDER))
 454                 seq_printf(seq, ",order=strict");
 455         if (nilfs_test_opt(sbi, NORECOVERY))
 456                 seq_printf(seq, ",norecovery");
 457         if (nilfs_test_opt(sbi, DISCARD))
 458                 seq_printf(seq, ",discard");
 459
 460         return 0;
 461 }
 462
 463 static const struct super_operations nilfs_sops = {
 464         .alloc_inode    = nilfs_alloc_inode,
 465         .destroy_inode  = nilfs_destroy_inode,
 466         .dirty_inode    = nilfs_dirty_inode,
 467         /* .write_inode    = nilfs_write_inode, */
 468         /* .put_inode      = nilfs_put_inode, */
 469         /* .drop_inode    = nilfs_drop_inode, */
 470         .delete_inode   = nilfs_delete_inode,
 471         .put_super      = nilfs_put_super,
 472         /* .write_super    = nilfs_write_super, */
 473         .sync_fs        = nilfs_sync_fs,
 474         /* .write_super_lockfs */
 475         /* .unlockfs */
 476         .statfs         = nilfs_statfs,
 477         .remount_fs     = nilfs_remount,
 478         .clear_inode    = nilfs_clear_inode,
 479         /* .umount_begin */
 480         .show_options = nilfs_show_options
 481 };
 482
 483 static struct inode *
 484 nilfs_nfs_get_inode(struct super_block *sb, u64 ino, u32 generation)
 485 {
 486         struct inode *inode;
 487
 488         if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO &&
 489             ino != NILFS_SKETCH_INO)
 490                 return ERR_PTR(-ESTALE);
 491
 492         inode = nilfs_iget(sb, ino);
 493         if (IS_ERR(inode))
 494                 return ERR_CAST(inode);
 495         if (generation && inode->i_generation != generation) {
 496                 iput(inode);
 497                 return ERR_PTR(-ESTALE);
 498         }
 499
 500         return inode;
 501 }
 502
 503 static struct dentry *
 504 nilfs_fh_to_dentry(struct super_block *sb, struct fid *fid, int fh_len,
 505                    int fh_type)
 506 {
 507         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 508                                     nilfs_nfs_get_inode);
 509 }
 510
 511 static struct dentry *
 512 nilfs_fh_to_parent(struct super_block *sb, struct fid *fid, int fh_len,
 513                    int fh_type)
 514 {
 515         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 516                                     nilfs_nfs_get_inode);
 517 }
 518
 519 static const struct export_operations nilfs_export_ops = {
 520         .fh_to_dentry = nilfs_fh_to_dentry,
 521         .fh_to_parent = nilfs_fh_to_parent,
 522         .get_parent = nilfs_get_parent,
 523 };
 524
 525 enum {
 526         Opt_err_cont, Opt_err_panic, Opt_err_ro,
 527         Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
 528         Opt_discard, Opt_err,
 529 };
 530
 531 static match_table_t tokens = {
 532         {Opt_err_cont, "errors=continue"},
 533         {Opt_err_panic, "errors=panic"},
 534         {Opt_err_ro, "errors=remount-ro"},
 535         {Opt_nobarrier, "nobarrier"},
 536         {Opt_snapshot, "cp=%u"},
 537         {Opt_order, "order=%s"},
 538         {Opt_norecovery, "norecovery"},
 539         {Opt_discard, "discard"},
 540         {Opt_err, NULL}
 541 };
 542
 543 static int parse_options(char *options, struct super_block *sb)
 544 {
 545         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 546         char *p;
 547         substring_t args[MAX_OPT_ARGS];
 548         int option;
 549
 550         if (!options)
 551                 return 1;
 552
 553         while ((p = strsep(&options, ",")) != NULL) {
 554                 int token;
 555                 if (!*p)
 556                         continue;
 557
 558                 token = match_token(p, tokens, args);
 559                 switch (token) {
 560                 case Opt_nobarrier:
 561                         nilfs_clear_opt(sbi, BARRIER);
 562                         break;
 563                 case Opt_order:
 564                         if (strcmp(args[0].from, "relaxed") == 0)
 565                                 /* Ordered data semantics */
 566                                 nilfs_clear_opt(sbi, STRICT_ORDER);
 567                         else if (strcmp(args[0].from, "strict") == 0)
 568                                 /* Strict in-order semantics */
 569                                 nilfs_set_opt(sbi, STRICT_ORDER);
 570                         else
 571                                 return 0;
 572                         break;
 573                 case Opt_err_panic:
 574                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_PANIC);
 575                         break;
 576                 case Opt_err_ro:
 577                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_RO);
 578                         break;
 579                 case Opt_err_cont:
 580                         nilfs_write_opt(sbi, ERROR_MODE, ERRORS_CONT);
 581                         break;
 582                 case Opt_snapshot:
 583                         if (match_int(&args[0], &option) || option <= 0)
 584                                 return 0;
 585                         if (!(sb->s_flags & MS_RDONLY))
 586                                 return 0;
 587                         sbi->s_snapshot_cno = option;
 588                         nilfs_set_opt(sbi, SNAPSHOT);
 589                         break;
 590                 case Opt_norecovery:
 591                         nilfs_set_opt(sbi, NORECOVERY);
 592                         break;
 593                 case Opt_discard:
 594                         nilfs_set_opt(sbi, DISCARD);
 595                         break;
 596                 default:
 597                         printk(KERN_ERR
 598                                "NILFS: Unrecognized mount option \"%s\"\n", p);
 599                         return 0;
 600                 }
 601         }
 602         return 1;
 603 }
 604
 605 static inline void
 606 nilfs_set_default_options(struct nilfs_sb_info *sbi,
 607                           struct nilfs_super_block *sbp)
 608 {
 609         sbi->s_mount_opt =
 610                 NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
 611 }
 612
 613 static int nilfs_setup_super(struct nilfs_sb_info *sbi)
 614 {
 615         struct the_nilfs *nilfs = sbi->s_nilfs;
 616         struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
 617         int max_mnt_count = le16_to_cpu(sbp->s_max_mnt_count);
 618         int mnt_count = le16_to_cpu(sbp->s_mnt_count);
 619
 620         /* nilfs->sem must be locked by the caller. */
 621         if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
 622                 printk(KERN_WARNING
 623                        "NILFS warning: mounting fs with errors\n");
 624 #if 0
 625         } else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
 626                 printk(KERN_WARNING
 627                        "NILFS warning: maximal mount count reached\n");
 628 #endif
 629         }
 630         if (!max_mnt_count)
 631                 sbp->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
 632
 633         sbp->s_mnt_count = cpu_to_le16(mnt_count + 1);
 634         sbp->s_state = cpu_to_le16(le16_to_cpu(sbp->s_state) & ~NILFS_VALID_FS);
 635         sbp->s_mtime = cpu_to_le64(get_seconds());
 636         return nilfs_commit_super(sbi, 1);
 637 }
 638
 639 struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
 640                                                  u64 pos, int blocksize,
 641                                                  struct buffer_head **pbh)
 642 {
 643         unsigned long long sb_index = pos;
 644         unsigned long offset;
 645
 646         offset = do_div(sb_index, blocksize);
 647         *pbh = sb_bread(sb, sb_index);
 648         if (!*pbh)
 649                 return NULL;
 650         return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
 651 }
 652
 653 int nilfs_store_magic_and_option(struct super_block *sb,
 654                                  struct nilfs_super_block *sbp,
 655                                  char *data)
 656 {
 657         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 658
 659         sb->s_magic = le16_to_cpu(sbp->s_magic);
 660
 661         /* FS independent flags */
 662 #ifdef NILFS_ATIME_DISABLE
 663         sb->s_flags |= MS_NOATIME;
 664 #endif
 665
 666         nilfs_set_default_options(sbi, sbp);
 667
 668         sbi->s_resuid = le16_to_cpu(sbp->s_def_resuid);
 669         sbi->s_resgid = le16_to_cpu(sbp->s_def_resgid);
 670         sbi->s_interval = le32_to_cpu(sbp->s_c_interval);
 671         sbi->s_watermark = le32_to_cpu(sbp->s_c_block_max);
 672
 673         return !parse_options(data, sb) ? -EINVAL : 0 ;
 674 }
 675
 676 /**
 677  * nilfs_fill_super() - initialize a super block instance
 678  * @sb: super_block
 679  * @data: mount options
 680  * @silent: silent mode flag
 681  * @nilfs: the_nilfs struct
 682  *
 683  * This function is called exclusively by nilfs->ns_mount_mutex.
 684  * So, the recovery process is protected from other simultaneous mounts.
 685  */
 686 static int
 687 nilfs_fill_super(struct super_block *sb, void *data, int silent,
 688                  struct the_nilfs *nilfs)
 689 {
 690         struct nilfs_sb_info *sbi;
 691         struct inode *root;
 692         __u64 cno;
 693         int err;
 694
 695         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 696         if (!sbi)
 697                 return -ENOMEM;
 698
 699         sb->s_fs_info = sbi;
 700
 701         get_nilfs(nilfs);
 702         sbi->s_nilfs = nilfs;
 703         sbi->s_super = sb;
 704         atomic_set(&sbi->s_count, 1);
 705
 706         err = init_nilfs(nilfs, sbi, (char *)data);
 707         if (err)
 708                 goto failed_sbi;
 709
 710         spin_lock_init(&sbi->s_inode_lock);
 711         INIT_LIST_HEAD(&sbi->s_dirty_files);
 712         INIT_LIST_HEAD(&sbi->s_list);
 713
 714         /*
 715          * Following initialization is overlapped because
 716          * nilfs_sb_info structure has been cleared at the beginning.
 717          * But we reserve them to keep our interest and make ready
 718          * for the future change.
 719          */
 720         get_random_bytes(&sbi->s_next_generation,
 721                          sizeof(sbi->s_next_generation));
 722         spin_lock_init(&sbi->s_next_gen_lock);
 723
 724         sb->s_op = &nilfs_sops;
 725         sb->s_export_op = &nilfs_export_ops;
 726         sb->s_root = NULL;
 727         sb->s_time_gran = 1;
 728         sb->s_bdi = nilfs->ns_bdi;
 729
 730         err = load_nilfs(nilfs, sbi);
 731         if (err)
 732                 goto failed_sbi;
 733
 734         cno = nilfs_last_cno(nilfs);
 735
 736         if (sb->s_flags & MS_RDONLY) {
 737                 if (nilfs_test_opt(sbi, SNAPSHOT)) {
 738                         down_read(&nilfs->ns_segctor_sem);
 739                         err = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile,
 740                                                        sbi->s_snapshot_cno);
 741                         up_read(&nilfs->ns_segctor_sem);
 742                         if (err < 0) {
 743                                 if (err == -ENOENT)
 744                                         err = -EINVAL;
 745                                 goto failed_sbi;
 746                         }
 747                         if (!err) {
 748                                 printk(KERN_ERR
 749                                        "NILFS: The specified checkpoint is "
 750                                        "not a snapshot "
 751                                        "(checkpoint number=%llu).\n",
 752                                        (unsigned long long)sbi->s_snapshot_cno);
 753                                 err = -EINVAL;
 754                                 goto failed_sbi;
 755                         }
 756                         cno = sbi->s_snapshot_cno;
 757                 }
 758         }
 759
 760         err = nilfs_attach_checkpoint(sbi, cno);
 761         if (err) {
 762                 printk(KERN_ERR "NILFS: error loading a checkpoint"
 763                        " (checkpoint number=%llu).\n", (unsigned long long)cno);
 764                 goto failed_sbi;
 765         }
 766
 767         if (!(sb->s_flags & MS_RDONLY)) {
 768                 err = nilfs_attach_segment_constructor(sbi);
 769                 if (err)
 770                         goto failed_checkpoint;
 771         }
 772
 773         root = nilfs_iget(sb, NILFS_ROOT_INO);
 774         if (IS_ERR(root)) {
 775                 printk(KERN_ERR "NILFS: get root inode failed\n");
 776                 err = PTR_ERR(root);
 777                 goto failed_segctor;
 778         }
 779         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
 780                 iput(root);
 781                 printk(KERN_ERR "NILFS: corrupt root inode.\n");
 782                 err = -EINVAL;
 783                 goto failed_segctor;
 784         }
 785         sb->s_root = d_alloc_root(root);
 786         if (!sb->s_root) {
 787                 iput(root);
 788                 printk(KERN_ERR "NILFS: get root dentry failed\n");
 789                 err = -ENOMEM;
 790                 goto failed_segctor;
 791         }
 792
 793         if (!(sb->s_flags & MS_RDONLY)) {
 794                 down_write(&nilfs->ns_sem);
 795                 nilfs_setup_super(sbi);
 796                 up_write(&nilfs->ns_sem);
 797         }
 798
 799         down_write(&nilfs->ns_super_sem);
 800         if (!nilfs_test_opt(sbi, SNAPSHOT))
 801                 nilfs->ns_current = sbi;
 802         up_write(&nilfs->ns_super_sem);
 803
 804         return 0;
 805
 806  failed_segctor:
 807         nilfs_detach_segment_constructor(sbi);
 808
 809  failed_checkpoint:
 810         nilfs_detach_checkpoint(sbi);
 811
 812  failed_sbi:
 813         put_nilfs(nilfs);
 814         sb->s_fs_info = NULL;
 815         nilfs_put_sbinfo(sbi);
 816         return err;
 817 }
 818
 819 static int nilfs_remount(struct super_block *sb, int *flags, char *data)
 820 {
 821         struct nilfs_sb_info *sbi = NILFS_SB(sb);
 822         struct nilfs_super_block *sbp;
 823         struct the_nilfs *nilfs = sbi->s_nilfs;
 824         unsigned long old_sb_flags;
 825         struct nilfs_mount_options old_opts;
 826         int was_snapshot, err;
 827
 828         lock_kernel();
 829
 830         down_write(&nilfs->ns_super_sem);
 831         old_sb_flags = sb->s_flags;
 832         old_opts.mount_opt = sbi->s_mount_opt;
 833         old_opts.snapshot_cno = sbi->s_snapshot_cno;
 834         was_snapshot = nilfs_test_opt(sbi, SNAPSHOT);
 835
 836         if (!parse_options(data, sb)) {
 837                 err = -EINVAL;
 838                 goto restore_opts;
 839         }
 840         sb->s_flags = (sb->s_flags & ~MS_POSIXACL);
 841
 842         err = -EINVAL;
 843         if (was_snapshot) {
 844                 if (!(*flags & MS_RDONLY)) {
 845                         printk(KERN_ERR "NILFS (device %s): cannot remount "
 846                                "snapshot read/write.\n",
 847                                sb->s_id);
 848                         goto restore_opts;
 849                 } else if (sbi->s_snapshot_cno != old_opts.snapshot_cno) {
 850                         printk(KERN_ERR "NILFS (device %s): cannot "
 851                                "remount to a different snapshot.\n",
 852                                sb->s_id);
 853                         goto restore_opts;
 854                 }
 855         } else {
 856                 if (nilfs_test_opt(sbi, SNAPSHOT)) {
 857                         printk(KERN_ERR "NILFS (device %s): cannot change "
 858                                "a regular mount to a snapshot.\n",
 859                                sb->s_id);
 860                         goto restore_opts;
 861                 }
 862         }
 863
 864         if (!nilfs_valid_fs(nilfs)) {
 865                 printk(KERN_WARNING "NILFS (device %s): couldn't "
 866                        "remount because the filesystem is in an "
 867                        "incomplete recovery state.\n", sb->s_id);
 868                 goto restore_opts;
 869         }
 870
 871         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 872                 goto out;
 873         if (*flags & MS_RDONLY) {
 874                 /* Shutting down the segment constructor */
 875                 nilfs_detach_segment_constructor(sbi);
 876                 sb->s_flags |= MS_RDONLY;
 877
 878                 /*
 879                  * Remounting a valid RW partition RDONLY, so set
 880                  * the RDONLY flag and then mark the partition as valid again.
 881                  */
 882                 down_write(&nilfs->ns_sem);
 883                 sbp = nilfs->ns_sbp[0];
 884                 if (!(sbp->s_state & le16_to_cpu(NILFS_VALID_FS)) &&
 885                     (nilfs->ns_mount_state & NILFS_VALID_FS))
 886                         sbp->s_state = cpu_to_le16(nilfs->ns_mount_state);
 887                 sbp->s_mtime = cpu_to_le64(get_seconds());
 888                 nilfs_commit_super(sbi, 1);
 889                 up_write(&nilfs->ns_sem);
 890         } else {
 891                 /*
 892                  * Mounting a RDONLY partition read-write, so reread and
 893                  * store the current valid flag.  (It may have been changed
 894                  * by fsck since we originally mounted the partition.)
 895                  */
 896                 sb->s_flags &= ~MS_RDONLY;
 897
 898                 err = nilfs_attach_segment_constructor(sbi);
 899                 if (err)
 900                         goto restore_opts;
 901
 902                 down_write(&nilfs->ns_sem);
 903                 nilfs_setup_super(sbi);
 904                 up_write(&nilfs->ns_sem);
 905         }
 906  out:
 907         up_write(&nilfs->ns_super_sem);
 908         unlock_kernel();
 909         return 0;
 910
 911  restore_opts:
 912         sb->s_flags = old_sb_flags;
 913         sbi->s_mount_opt = old_opts.mount_opt;
 914         sbi->s_snapshot_cno = old_opts.snapshot_cno;
 915         up_write(&nilfs->ns_super_sem);
 916         unlock_kernel();
 917         return err;
 918 }
 919
 920 struct nilfs_super_data {
 921         struct block_device *bdev;
 922         struct nilfs_sb_info *sbi;
 923         __u64 cno;
 924         int flags;
 925 };
 926
 927 /**
 928  * nilfs_identify - pre-read mount options needed to identify mount instance
 929  * @data: mount options
 930  * @sd: nilfs_super_data
 931  */
 932 static int nilfs_identify(char *data, struct nilfs_super_data *sd)
 933 {
 934         char *p, *options = data;
 935         substring_t args[MAX_OPT_ARGS];
 936         int option, token;
 937         int ret = 0;
 938
 939         do {
 940                 p = strsep(&options, ",");
 941                 if (p != NULL && *p) {
 942                         token = match_token(p, tokens, args);
 943                         if (token == Opt_snapshot) {
 944                                 if (!(sd->flags & MS_RDONLY))
 945                                         ret++;
 946                                 else {
 947                                         ret = match_int(&args[0], &option);
 948                                         if (!ret) {
 949                                                 if (option > 0)
 950                                                         sd->cno = option;
 951                                                 else
 952                                                         ret++;
 953                                         }
 954                                 }
 955                         }
 956                         if (ret)
 957                                 printk(KERN_ERR
 958                                        "NILFS: invalid mount option: %s\n", p);
 959                 }
 960                 if (!options)
 961                         break;
 962                 BUG_ON(options == data);
 963                 *(options - 1) = ',';
 964         } while (!ret);
 965         return ret;
 966 }
 967
 968 static int nilfs_set_bdev_super(struct super_block *s, void *data)
 969 {
 970         struct nilfs_super_data *sd = data;
 971
 972         s->s_bdev = sd->bdev;
 973         s->s_dev = s->s_bdev->bd_dev;
 974         return 0;
 975 }
 976
 977 static int nilfs_test_bdev_super(struct super_block *s, void *data)
 978 {
 979         struct nilfs_super_data *sd = data;
 980
 981         return sd->sbi && s->s_fs_info == (void *)sd->sbi;
 982 }
 983
 984 static int
 985 nilfs_get_sb(struct file_system_type *fs_type, int flags,
 986              const char *dev_name, void *data, struct vfsmount *mnt)
 987 {
 988         struct nilfs_super_data sd;
 989         struct super_block *s;
 990         fmode_t mode = FMODE_READ;
 991         struct the_nilfs *nilfs;
 992         int err, need_to_close = 1;
 993
 994         if (!(flags & MS_RDONLY))
 995                 mode |= FMODE_WRITE;
 996
 997         sd.bdev = open_bdev_exclusive(dev_name, mode, fs_type);
 998         if (IS_ERR(sd.bdev))
 999                 return PTR_ERR(sd.bdev);
1000
1001         /*
1002          * To get mount instance using sget() vfs-routine, NILFS needs
1003          * much more information than normal filesystems to identify mount
1004          * instance.  For snapshot mounts, not only a mount type (ro-mount
1005          * or rw-mount) but also a checkpoint number is required.
1006          */
1007         sd.cno = 0;
1008         sd.flags = flags;
1009         if (nilfs_identify((char *)data, &sd)) {
1010                 err = -EINVAL;
1011                 goto failed;
1012         }
1013
1014         nilfs = find_or_create_nilfs(sd.bdev);
1015         if (!nilfs) {
1016                 err = -ENOMEM;
1017                 goto failed;
1018         }
1019
1020         mutex_lock(&nilfs->ns_mount_mutex);
1021
1022         if (!sd.cno) {
1023                 /*
1024                  * Check if an exclusive mount exists or not.
1025                  * Snapshot mounts coexist with a current mount
1026                  * (i.e. rw-mount or ro-mount), whereas rw-mount and
1027                  * ro-mount are mutually exclusive.
1028                  */
1029                 down_read(&nilfs->ns_super_sem);
1030                 if (nilfs->ns_current &&
1031                     ((nilfs->ns_current->s_super->s_flags ^ flags)
1032                      & MS_RDONLY)) {
1033                         up_read(&nilfs->ns_super_sem);
1034                         err = -EBUSY;
1035                         goto failed_unlock;
1036                 }
1037                 up_read(&nilfs->ns_super_sem);
1038         }
1039
1040         /*
1041          * Find existing nilfs_sb_info struct
1042          */
1043         sd.sbi = nilfs_find_sbinfo(nilfs, !(flags & MS_RDONLY), sd.cno);
1044
1045         /*
1046          * Get super block instance holding the nilfs_sb_info struct.
1047          * A new instance is allocated if no existing mount is present or
1048          * existing instance has been unmounted.
1049          */
1050         s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, &sd);
1051         if (sd.sbi)
1052                 nilfs_put_sbinfo(sd.sbi);
1053
1054         if (IS_ERR(s)) {
1055                 err = PTR_ERR(s);
1056                 goto failed_unlock;
1057         }
1058
1059         if (!s->s_root) {
1060                 char b[BDEVNAME_SIZE];
1061
1062                 /* New superblock instance created */
1063                 s->s_flags = flags;
1064                 s->s_mode = mode;
1065                 strlcpy(s->s_id, bdevname(sd.bdev, b), sizeof(s->s_id));
1066                 sb_set_blocksize(s, block_size(sd.bdev));
1067
1068                 err = nilfs_fill_super(s, data, flags & MS_SILENT ? 1 : 0,
1069                                        nilfs);
1070                 if (err)
1071                         goto cancel_new;
1072
1073                 s->s_flags |= MS_ACTIVE;
1074                 need_to_close = 0;
1075         }
1076
1077         mutex_unlock(&nilfs->ns_mount_mutex);
1078         put_nilfs(nilfs);
1079         if (need_to_close)
1080                 close_bdev_exclusive(sd.bdev, mode);
1081         simple_set_mnt(mnt, s);
1082         return 0;
1083
1084  failed_unlock:
1085         mutex_unlock(&nilfs->ns_mount_mutex);
1086         put_nilfs(nilfs);
1087  failed:
1088         close_bdev_exclusive(sd.bdev, mode);
1089
1090         return err;
1091
1092  cancel_new:
1093         /* Abandoning the newly allocated superblock */
1094         mutex_unlock(&nilfs->ns_mount_mutex);
1095         put_nilfs(nilfs);
1096         deactivate_locked_super(s);
1097         /*
1098          * deactivate_locked_super() invokes close_bdev_exclusive().
1099          * We must finish all post-cleaning before this call;
1100          * put_nilfs() needs the block device.
1101          */
1102         return err;
1103 }
1104
1105 struct file_system_type nilfs_fs_type = {
1106         .owner    = THIS_MODULE,
1107         .name     = "nilfs2",
1108         .get_sb   = nilfs_get_sb,
1109         .kill_sb  = kill_block_super,
1110         .fs_flags = FS_REQUIRES_DEV,
1111 };
1112
1113 static void nilfs_inode_init_once(void *obj)
1114 {
1115         struct nilfs_inode_info *ii = obj;
1116
1117         INIT_LIST_HEAD(&ii->i_dirty);
1118 #ifdef CONFIG_NILFS_XATTR
1119         init_rwsem(&ii->xattr_sem);
1120 #endif
1121         nilfs_btnode_cache_init_once(&ii->i_btnode_cache);
1122         ii->i_bmap = (struct nilfs_bmap *)&ii->i_bmap_union;
1123         inode_init_once(&ii->vfs_inode);
1124 }
1125
1126 static void nilfs_segbuf_init_once(void *obj)
1127 {
1128         memset(obj, 0, sizeof(struct nilfs_segment_buffer));
1129 }
1130
1131 static void nilfs_destroy_cachep(void)
1132 {
1133          if (nilfs_inode_cachep)
1134                 kmem_cache_destroy(nilfs_inode_cachep);
1135          if (nilfs_transaction_cachep)
1136                 kmem_cache_destroy(nilfs_transaction_cachep);
1137          if (nilfs_segbuf_cachep)
1138                 kmem_cache_destroy(nilfs_segbuf_cachep);
1139          if (nilfs_btree_path_cache)
1140                 kmem_cache_destroy(nilfs_btree_path_cache);
1141 }
1142
1143 static int __init nilfs_init_cachep(void)
1144 {
1145         nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
1146                         sizeof(struct nilfs_inode_info), 0,
1147                         SLAB_RECLAIM_ACCOUNT, nilfs_inode_init_once);
1148         if (!nilfs_inode_cachep)
1149                 goto fail;
1150
1151         nilfs_transaction_cachep = kmem_cache_create("nilfs2_transaction_cache",
1152                         sizeof(struct nilfs_transaction_info), 0,
1153                         SLAB_RECLAIM_ACCOUNT, NULL);
1154         if (!nilfs_transaction_cachep)
1155                 goto fail;
1156
1157         nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache",
1158                         sizeof(struct nilfs_segment_buffer), 0,
1159                         SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once);
1160         if (!nilfs_segbuf_cachep)
1161                 goto fail;
1162
1163         nilfs_btree_path_cache = kmem_cache_create("nilfs2_btree_path_cache",
1164                         sizeof(struct nilfs_btree_path) * NILFS_BTREE_LEVEL_MAX,
1165                         0, 0, NULL);
1166         if (!nilfs_btree_path_cache)
1167                 goto fail;
1168
1169         return 0;
1170
1171 fail:
1172         nilfs_destroy_cachep();
1173         return -ENOMEM;
1174 }
1175
1176 static int __init init_nilfs_fs(void)
1177 {
1178         int err;
1179
1180         err = nilfs_init_cachep();
1181         if (err)
1182                 goto fail;
1183
1184         err = register_filesystem(&nilfs_fs_type);
1185         if (err)
1186                 goto free_cachep;
1187
1188         printk(KERN_INFO "NILFS version 2 loaded\n");
1189         return 0;
1190
1191 free_cachep:
1192         nilfs_destroy_cachep();
1193 fail:
1194         return err;
1195 }
1196
1197 static void __exit exit_nilfs_fs(void)
1198 {
1199         nilfs_destroy_cachep();
1200         unregister_filesystem(&nilfs_fs_type);
1201 }
1202
1203 module_init(init_nilfs_fs)
1204 module_exit(exit_nilfs_fs)