linux/fs/nilfs2/super.c
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   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/crc32.h>
  47#include <linux/vfs.h>
  48#include <linux/writeback.h>
  49#include <linux/seq_file.h>
  50#include <linux/mount.h>
  51#include "nilfs.h"
  52#include "export.h"
  53#include "mdt.h"
  54#include "alloc.h"
  55#include "btree.h"
  56#include "btnode.h"
  57#include "page.h"
  58#include "cpfile.h"
  59#include "sufile.h" /* nilfs_sufile_resize(), nilfs_sufile_set_alloc_range() */
  60#include "ifile.h"
  61#include "dat.h"
  62#include "segment.h"
  63#include "segbuf.h"
  64
  65MODULE_AUTHOR("NTT Corp.");
  66MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
  67                   "(NILFS)");
  68MODULE_LICENSE("GPL");
  69
  70static struct kmem_cache *nilfs_inode_cachep;
  71struct kmem_cache *nilfs_transaction_cachep;
  72struct kmem_cache *nilfs_segbuf_cachep;
  73struct kmem_cache *nilfs_btree_path_cache;
  74
  75static int nilfs_setup_super(struct super_block *sb, int is_mount);
  76static int nilfs_remount(struct super_block *sb, int *flags, char *data);
  77
  78static void nilfs_set_error(struct super_block *sb)
  79{
  80        struct the_nilfs *nilfs = sb->s_fs_info;
  81        struct nilfs_super_block **sbp;
  82
  83        down_write(&nilfs->ns_sem);
  84        if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
  85                nilfs->ns_mount_state |= NILFS_ERROR_FS;
  86                sbp = nilfs_prepare_super(sb, 0);
  87                if (likely(sbp)) {
  88                        sbp[0]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
  89                        if (sbp[1])
  90                                sbp[1]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
  91                        nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
  92                }
  93        }
  94        up_write(&nilfs->ns_sem);
  95}
  96
  97/**
  98 * nilfs_error() - report failure condition on a filesystem
  99 *
 100 * nilfs_error() sets an ERROR_FS flag on the superblock as well as
 101 * reporting an error message.  It should be called when NILFS detects
 102 * incoherences or defects of meta data on disk.  As for sustainable
 103 * errors such as a single-shot I/O error, nilfs_warning() or the printk()
 104 * function should be used instead.
 105 *
 106 * The segment constructor must not call this function because it can
 107 * kill itself.
 108 */
 109void nilfs_error(struct super_block *sb, const char *function,
 110                 const char *fmt, ...)
 111{
 112        struct the_nilfs *nilfs = sb->s_fs_info;
 113        struct va_format vaf;
 114        va_list args;
 115
 116        va_start(args, fmt);
 117
 118        vaf.fmt = fmt;
 119        vaf.va = &args;
 120
 121        printk(KERN_CRIT "NILFS error (device %s): %s: %pV\n",
 122               sb->s_id, function, &vaf);
 123
 124        va_end(args);
 125
 126        if (!(sb->s_flags & MS_RDONLY)) {
 127                nilfs_set_error(sb);
 128
 129                if (nilfs_test_opt(nilfs, ERRORS_RO)) {
 130                        printk(KERN_CRIT "Remounting filesystem read-only\n");
 131                        sb->s_flags |= MS_RDONLY;
 132                }
 133        }
 134
 135        if (nilfs_test_opt(nilfs, ERRORS_PANIC))
 136                panic("NILFS (device %s): panic forced after error\n",
 137                      sb->s_id);
 138}
 139
 140void nilfs_warning(struct super_block *sb, const char *function,
 141                   const char *fmt, ...)
 142{
 143        struct va_format vaf;
 144        va_list args;
 145
 146        va_start(args, fmt);
 147
 148        vaf.fmt = fmt;
 149        vaf.va = &args;
 150
 151        printk(KERN_WARNING "NILFS warning (device %s): %s: %pV\n",
 152               sb->s_id, function, &vaf);
 153
 154        va_end(args);
 155}
 156
 157
 158struct inode *nilfs_alloc_inode(struct super_block *sb)
 159{
 160        struct nilfs_inode_info *ii;
 161
 162        ii = kmem_cache_alloc(nilfs_inode_cachep, GFP_NOFS);
 163        if (!ii)
 164                return NULL;
 165        ii->i_bh = NULL;
 166        ii->i_state = 0;
 167        ii->i_cno = 0;
 168        ii->vfs_inode.i_version = 1;
 169        nilfs_mapping_init(&ii->i_btnode_cache, &ii->vfs_inode, sb->s_bdi);
 170        return &ii->vfs_inode;
 171}
 172
 173static void nilfs_i_callback(struct rcu_head *head)
 174{
 175        struct inode *inode = container_of(head, struct inode, i_rcu);
 176        struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
 177
 178        if (mdi) {
 179                kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
 180                kfree(mdi);
 181        }
 182        kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
 183}
 184
 185void nilfs_destroy_inode(struct inode *inode)
 186{
 187        call_rcu(&inode->i_rcu, nilfs_i_callback);
 188}
 189
 190static int nilfs_sync_super(struct super_block *sb, int flag)
 191{
 192        struct the_nilfs *nilfs = sb->s_fs_info;
 193        int err;
 194
 195 retry:
 196        set_buffer_dirty(nilfs->ns_sbh[0]);
 197        if (nilfs_test_opt(nilfs, BARRIER)) {
 198                err = __sync_dirty_buffer(nilfs->ns_sbh[0],
 199                                          WRITE_SYNC | WRITE_FLUSH_FUA);
 200        } else {
 201                err = sync_dirty_buffer(nilfs->ns_sbh[0]);
 202        }
 203
 204        if (unlikely(err)) {
 205                printk(KERN_ERR
 206                       "NILFS: unable to write superblock (err=%d)\n", err);
 207                if (err == -EIO && nilfs->ns_sbh[1]) {
 208                        /*
 209                         * sbp[0] points to newer log than sbp[1],
 210                         * so copy sbp[0] to sbp[1] to take over sbp[0].
 211                         */
 212                        memcpy(nilfs->ns_sbp[1], nilfs->ns_sbp[0],
 213                               nilfs->ns_sbsize);
 214                        nilfs_fall_back_super_block(nilfs);
 215                        goto retry;
 216                }
 217        } else {
 218                struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
 219
 220                nilfs->ns_sbwcount++;
 221
 222                /*
 223                 * The latest segment becomes trailable from the position
 224                 * written in superblock.
 225                 */
 226                clear_nilfs_discontinued(nilfs);
 227
 228                /* update GC protection for recent segments */
 229                if (nilfs->ns_sbh[1]) {
 230                        if (flag == NILFS_SB_COMMIT_ALL) {
 231                                set_buffer_dirty(nilfs->ns_sbh[1]);
 232                                if (sync_dirty_buffer(nilfs->ns_sbh[1]) < 0)
 233                                        goto out;
 234                        }
 235                        if (le64_to_cpu(nilfs->ns_sbp[1]->s_last_cno) <
 236                            le64_to_cpu(nilfs->ns_sbp[0]->s_last_cno))
 237                                sbp = nilfs->ns_sbp[1];
 238                }
 239
 240                spin_lock(&nilfs->ns_last_segment_lock);
 241                nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
 242                spin_unlock(&nilfs->ns_last_segment_lock);
 243        }
 244 out:
 245        return err;
 246}
 247
 248void nilfs_set_log_cursor(struct nilfs_super_block *sbp,
 249                          struct the_nilfs *nilfs)
 250{
 251        sector_t nfreeblocks;
 252
 253        /* nilfs->ns_sem must be locked by the caller. */
 254        nilfs_count_free_blocks(nilfs, &nfreeblocks);
 255        sbp->s_free_blocks_count = cpu_to_le64(nfreeblocks);
 256
 257        spin_lock(&nilfs->ns_last_segment_lock);
 258        sbp->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
 259        sbp->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
 260        sbp->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
 261        spin_unlock(&nilfs->ns_last_segment_lock);
 262}
 263
 264struct nilfs_super_block **nilfs_prepare_super(struct super_block *sb,
 265                                               int flip)
 266{
 267        struct the_nilfs *nilfs = sb->s_fs_info;
 268        struct nilfs_super_block **sbp = nilfs->ns_sbp;
 269
 270        /* nilfs->ns_sem must be locked by the caller. */
 271        if (sbp[0]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 272                if (sbp[1] &&
 273                    sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC)) {
 274                        memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
 275                } else {
 276                        printk(KERN_CRIT "NILFS: superblock broke on dev %s\n",
 277                               sb->s_id);
 278                        return NULL;
 279                }
 280        } else if (sbp[1] &&
 281                   sbp[1]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 282                        memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 283        }
 284
 285        if (flip && sbp[1])
 286                nilfs_swap_super_block(nilfs);
 287
 288        return sbp;
 289}
 290
 291int nilfs_commit_super(struct super_block *sb, int flag)
 292{
 293        struct the_nilfs *nilfs = sb->s_fs_info;
 294        struct nilfs_super_block **sbp = nilfs->ns_sbp;
 295        time_t t;
 296
 297        /* nilfs->ns_sem must be locked by the caller. */
 298        t = get_seconds();
 299        nilfs->ns_sbwtime = t;
 300        sbp[0]->s_wtime = cpu_to_le64(t);
 301        sbp[0]->s_sum = 0;
 302        sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 303                                             (unsigned char *)sbp[0],
 304                                             nilfs->ns_sbsize));
 305        if (flag == NILFS_SB_COMMIT_ALL && sbp[1]) {
 306                sbp[1]->s_wtime = sbp[0]->s_wtime;
 307                sbp[1]->s_sum = 0;
 308                sbp[1]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 309                                            (unsigned char *)sbp[1],
 310                                            nilfs->ns_sbsize));
 311        }
 312        clear_nilfs_sb_dirty(nilfs);
 313        nilfs->ns_flushed_device = 1;
 314        /* make sure store to ns_flushed_device cannot be reordered */
 315        smp_wmb();
 316        return nilfs_sync_super(sb, flag);
 317}
 318
 319/**
 320 * nilfs_cleanup_super() - write filesystem state for cleanup
 321 * @sb: super block instance to be unmounted or degraded to read-only
 322 *
 323 * This function restores state flags in the on-disk super block.
 324 * This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
 325 * filesystem was not clean previously.
 326 */
 327int nilfs_cleanup_super(struct super_block *sb)
 328{
 329        struct the_nilfs *nilfs = sb->s_fs_info;
 330        struct nilfs_super_block **sbp;
 331        int flag = NILFS_SB_COMMIT;
 332        int ret = -EIO;
 333
 334        sbp = nilfs_prepare_super(sb, 0);
 335        if (sbp) {
 336                sbp[0]->s_state = cpu_to_le16(nilfs->ns_mount_state);
 337                nilfs_set_log_cursor(sbp[0], nilfs);
 338                if (sbp[1] && sbp[0]->s_last_cno == sbp[1]->s_last_cno) {
 339                        /*
 340                         * make the "clean" flag also to the opposite
 341                         * super block if both super blocks point to
 342                         * the same checkpoint.
 343                         */
 344                        sbp[1]->s_state = sbp[0]->s_state;
 345                        flag = NILFS_SB_COMMIT_ALL;
 346                }
 347                ret = nilfs_commit_super(sb, flag);
 348        }
 349        return ret;
 350}
 351
 352/**
 353 * nilfs_move_2nd_super - relocate secondary super block
 354 * @sb: super block instance
 355 * @sb2off: new offset of the secondary super block (in bytes)
 356 */
 357static int nilfs_move_2nd_super(struct super_block *sb, loff_t sb2off)
 358{
 359        struct the_nilfs *nilfs = sb->s_fs_info;
 360        struct buffer_head *nsbh;
 361        struct nilfs_super_block *nsbp;
 362        sector_t blocknr, newblocknr;
 363        unsigned long offset;
 364        int sb2i = -1;  /* array index of the secondary superblock */
 365        int ret = 0;
 366
 367        /* nilfs->ns_sem must be locked by the caller. */
 368        if (nilfs->ns_sbh[1] &&
 369            nilfs->ns_sbh[1]->b_blocknr > nilfs->ns_first_data_block) {
 370                sb2i = 1;
 371                blocknr = nilfs->ns_sbh[1]->b_blocknr;
 372        } else if (nilfs->ns_sbh[0]->b_blocknr > nilfs->ns_first_data_block) {
 373                sb2i = 0;
 374                blocknr = nilfs->ns_sbh[0]->b_blocknr;
 375        }
 376        if (sb2i >= 0 && (u64)blocknr << nilfs->ns_blocksize_bits == sb2off)
 377                goto out;  /* super block location is unchanged */
 378
 379        /* Get new super block buffer */
 380        newblocknr = sb2off >> nilfs->ns_blocksize_bits;
 381        offset = sb2off & (nilfs->ns_blocksize - 1);
 382        nsbh = sb_getblk(sb, newblocknr);
 383        if (!nsbh) {
 384                printk(KERN_WARNING
 385                       "NILFS warning: unable to move secondary superblock "
 386                       "to block %llu\n", (unsigned long long)newblocknr);
 387                ret = -EIO;
 388                goto out;
 389        }
 390        nsbp = (void *)nsbh->b_data + offset;
 391        memset(nsbp, 0, nilfs->ns_blocksize);
 392
 393        if (sb2i >= 0) {
 394                memcpy(nsbp, nilfs->ns_sbp[sb2i], nilfs->ns_sbsize);
 395                brelse(nilfs->ns_sbh[sb2i]);
 396                nilfs->ns_sbh[sb2i] = nsbh;
 397                nilfs->ns_sbp[sb2i] = nsbp;
 398        } else if (nilfs->ns_sbh[0]->b_blocknr < nilfs->ns_first_data_block) {
 399                /* secondary super block will be restored to index 1 */
 400                nilfs->ns_sbh[1] = nsbh;
 401                nilfs->ns_sbp[1] = nsbp;
 402        } else {
 403                brelse(nsbh);
 404        }
 405out:
 406        return ret;
 407}
 408
 409/**
 410 * nilfs_resize_fs - resize the filesystem
 411 * @sb: super block instance
 412 * @newsize: new size of the filesystem (in bytes)
 413 */
 414int nilfs_resize_fs(struct super_block *sb, __u64 newsize)
 415{
 416        struct the_nilfs *nilfs = sb->s_fs_info;
 417        struct nilfs_super_block **sbp;
 418        __u64 devsize, newnsegs;
 419        loff_t sb2off;
 420        int ret;
 421
 422        ret = -ERANGE;
 423        devsize = i_size_read(sb->s_bdev->bd_inode);
 424        if (newsize > devsize)
 425                goto out;
 426
 427        /*
 428         * Write lock is required to protect some functions depending
 429         * on the number of segments, the number of reserved segments,
 430         * and so forth.
 431         */
 432        down_write(&nilfs->ns_segctor_sem);
 433
 434        sb2off = NILFS_SB2_OFFSET_BYTES(newsize);
 435        newnsegs = sb2off >> nilfs->ns_blocksize_bits;
 436        do_div(newnsegs, nilfs->ns_blocks_per_segment);
 437
 438        ret = nilfs_sufile_resize(nilfs->ns_sufile, newnsegs);
 439        up_write(&nilfs->ns_segctor_sem);
 440        if (ret < 0)
 441                goto out;
 442
 443        ret = nilfs_construct_segment(sb);
 444        if (ret < 0)
 445                goto out;
 446
 447        down_write(&nilfs->ns_sem);
 448        nilfs_move_2nd_super(sb, sb2off);
 449        ret = -EIO;
 450        sbp = nilfs_prepare_super(sb, 0);
 451        if (likely(sbp)) {
 452                nilfs_set_log_cursor(sbp[0], nilfs);
 453                /*
 454                 * Drop NILFS_RESIZE_FS flag for compatibility with
 455                 * mount-time resize which may be implemented in a
 456                 * future release.
 457                 */
 458                sbp[0]->s_state = cpu_to_le16(le16_to_cpu(sbp[0]->s_state) &
 459                                              ~NILFS_RESIZE_FS);
 460                sbp[0]->s_dev_size = cpu_to_le64(newsize);
 461                sbp[0]->s_nsegments = cpu_to_le64(nilfs->ns_nsegments);
 462                if (sbp[1])
 463                        memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 464                ret = nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
 465        }
 466        up_write(&nilfs->ns_sem);
 467
 468        /*
 469         * Reset the range of allocatable segments last.  This order
 470         * is important in the case of expansion because the secondary
 471         * superblock must be protected from log write until migration
 472         * completes.
 473         */
 474        if (!ret)
 475                nilfs_sufile_set_alloc_range(nilfs->ns_sufile, 0, newnsegs - 1);
 476out:
 477        return ret;
 478}
 479
 480static void nilfs_put_super(struct super_block *sb)
 481{
 482        struct the_nilfs *nilfs = sb->s_fs_info;
 483
 484        nilfs_detach_log_writer(sb);
 485
 486        if (!(sb->s_flags & MS_RDONLY)) {
 487                down_write(&nilfs->ns_sem);
 488                nilfs_cleanup_super(sb);
 489                up_write(&nilfs->ns_sem);
 490        }
 491
 492        iput(nilfs->ns_sufile);
 493        iput(nilfs->ns_cpfile);
 494        iput(nilfs->ns_dat);
 495
 496        destroy_nilfs(nilfs);
 497        sb->s_fs_info = NULL;
 498}
 499
 500static int nilfs_sync_fs(struct super_block *sb, int wait)
 501{
 502        struct the_nilfs *nilfs = sb->s_fs_info;
 503        struct nilfs_super_block **sbp;
 504        int err = 0;
 505
 506        /* This function is called when super block should be written back */
 507        if (wait)
 508                err = nilfs_construct_segment(sb);
 509
 510        down_write(&nilfs->ns_sem);
 511        if (nilfs_sb_dirty(nilfs)) {
 512                sbp = nilfs_prepare_super(sb, nilfs_sb_will_flip(nilfs));
 513                if (likely(sbp)) {
 514                        nilfs_set_log_cursor(sbp[0], nilfs);
 515                        nilfs_commit_super(sb, NILFS_SB_COMMIT);
 516                }
 517        }
 518        up_write(&nilfs->ns_sem);
 519
 520        if (!err)
 521                err = nilfs_flush_device(nilfs);
 522
 523        return err;
 524}
 525
 526int nilfs_attach_checkpoint(struct super_block *sb, __u64 cno, int curr_mnt,
 527                            struct nilfs_root **rootp)
 528{
 529        struct the_nilfs *nilfs = sb->s_fs_info;
 530        struct nilfs_root *root;
 531        struct nilfs_checkpoint *raw_cp;
 532        struct buffer_head *bh_cp;
 533        int err = -ENOMEM;
 534
 535        root = nilfs_find_or_create_root(
 536                nilfs, curr_mnt ? NILFS_CPTREE_CURRENT_CNO : cno);
 537        if (!root)
 538                return err;
 539
 540        if (root->ifile)
 541                goto reuse; /* already attached checkpoint */
 542
 543        down_read(&nilfs->ns_segctor_sem);
 544        err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
 545                                          &bh_cp);
 546        up_read(&nilfs->ns_segctor_sem);
 547        if (unlikely(err)) {
 548                if (err == -ENOENT || err == -EINVAL) {
 549                        printk(KERN_ERR
 550                               "NILFS: Invalid checkpoint "
 551                               "(checkpoint number=%llu)\n",
 552                               (unsigned long long)cno);
 553                        err = -EINVAL;
 554                }
 555                goto failed;
 556        }
 557
 558        err = nilfs_ifile_read(sb, root, nilfs->ns_inode_size,
 559                               &raw_cp->cp_ifile_inode, &root->ifile);
 560        if (err)
 561                goto failed_bh;
 562
 563        atomic64_set(&root->inodes_count,
 564                        le64_to_cpu(raw_cp->cp_inodes_count));
 565        atomic64_set(&root->blocks_count,
 566                        le64_to_cpu(raw_cp->cp_blocks_count));
 567
 568        nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 569
 570 reuse:
 571        *rootp = root;
 572        return 0;
 573
 574 failed_bh:
 575        nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 576 failed:
 577        nilfs_put_root(root);
 578
 579        return err;
 580}
 581
 582static int nilfs_freeze(struct super_block *sb)
 583{
 584        struct the_nilfs *nilfs = sb->s_fs_info;
 585        int err;
 586
 587        if (sb->s_flags & MS_RDONLY)
 588                return 0;
 589
 590        /* Mark super block clean */
 591        down_write(&nilfs->ns_sem);
 592        err = nilfs_cleanup_super(sb);
 593        up_write(&nilfs->ns_sem);
 594        return err;
 595}
 596
 597static int nilfs_unfreeze(struct super_block *sb)
 598{
 599        struct the_nilfs *nilfs = sb->s_fs_info;
 600
 601        if (sb->s_flags & MS_RDONLY)
 602                return 0;
 603
 604        down_write(&nilfs->ns_sem);
 605        nilfs_setup_super(sb, false);
 606        up_write(&nilfs->ns_sem);
 607        return 0;
 608}
 609
 610static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 611{
 612        struct super_block *sb = dentry->d_sb;
 613        struct nilfs_root *root = NILFS_I(dentry->d_inode)->i_root;
 614        struct the_nilfs *nilfs = root->nilfs;
 615        u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 616        unsigned long long blocks;
 617        unsigned long overhead;
 618        unsigned long nrsvblocks;
 619        sector_t nfreeblocks;
 620        u64 nmaxinodes, nfreeinodes;
 621        int err;
 622
 623        /*
 624         * Compute all of the segment blocks
 625         *
 626         * The blocks before first segment and after last segment
 627         * are excluded.
 628         */
 629        blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
 630                - nilfs->ns_first_data_block;
 631        nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
 632
 633        /*
 634         * Compute the overhead
 635         *
 636         * When distributing meta data blocks outside segment structure,
 637         * We must count them as the overhead.
 638         */
 639        overhead = 0;
 640
 641        err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
 642        if (unlikely(err))
 643                return err;
 644
 645        err = nilfs_ifile_count_free_inodes(root->ifile,
 646                                            &nmaxinodes, &nfreeinodes);
 647        if (unlikely(err)) {
 648                printk(KERN_WARNING
 649                        "NILFS warning: fail to count free inodes: err %d.\n",
 650                        err);
 651                if (err == -ERANGE) {
 652                        /*
 653                         * If nilfs_palloc_count_max_entries() returns
 654                         * -ERANGE error code then we simply treat
 655                         * curent inodes count as maximum possible and
 656                         * zero as free inodes value.
 657                         */
 658                        nmaxinodes = atomic64_read(&root->inodes_count);
 659                        nfreeinodes = 0;
 660                        err = 0;
 661                } else
 662                        return err;
 663        }
 664
 665        buf->f_type = NILFS_SUPER_MAGIC;
 666        buf->f_bsize = sb->s_blocksize;
 667        buf->f_blocks = blocks - overhead;
 668        buf->f_bfree = nfreeblocks;
 669        buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
 670                (buf->f_bfree - nrsvblocks) : 0;
 671        buf->f_files = nmaxinodes;
 672        buf->f_ffree = nfreeinodes;
 673        buf->f_namelen = NILFS_NAME_LEN;
 674        buf->f_fsid.val[0] = (u32)id;
 675        buf->f_fsid.val[1] = (u32)(id >> 32);
 676
 677        return 0;
 678}
 679
 680static int nilfs_show_options(struct seq_file *seq, struct dentry *dentry)
 681{
 682        struct super_block *sb = dentry->d_sb;
 683        struct the_nilfs *nilfs = sb->s_fs_info;
 684        struct nilfs_root *root = NILFS_I(dentry->d_inode)->i_root;
 685
 686        if (!nilfs_test_opt(nilfs, BARRIER))
 687                seq_puts(seq, ",nobarrier");
 688        if (root->cno != NILFS_CPTREE_CURRENT_CNO)
 689                seq_printf(seq, ",cp=%llu", (unsigned long long)root->cno);
 690        if (nilfs_test_opt(nilfs, ERRORS_PANIC))
 691                seq_puts(seq, ",errors=panic");
 692        if (nilfs_test_opt(nilfs, ERRORS_CONT))
 693                seq_puts(seq, ",errors=continue");
 694        if (nilfs_test_opt(nilfs, STRICT_ORDER))
 695                seq_puts(seq, ",order=strict");
 696        if (nilfs_test_opt(nilfs, NORECOVERY))
 697                seq_puts(seq, ",norecovery");
 698        if (nilfs_test_opt(nilfs, DISCARD))
 699                seq_puts(seq, ",discard");
 700
 701        return 0;
 702}
 703
 704static const struct super_operations nilfs_sops = {
 705        .alloc_inode    = nilfs_alloc_inode,
 706        .destroy_inode  = nilfs_destroy_inode,
 707        .dirty_inode    = nilfs_dirty_inode,
 708        .evict_inode    = nilfs_evict_inode,
 709        .put_super      = nilfs_put_super,
 710        .sync_fs        = nilfs_sync_fs,
 711        .freeze_fs      = nilfs_freeze,
 712        .unfreeze_fs    = nilfs_unfreeze,
 713        .statfs         = nilfs_statfs,
 714        .remount_fs     = nilfs_remount,
 715        .show_options = nilfs_show_options
 716};
 717
 718enum {
 719        Opt_err_cont, Opt_err_panic, Opt_err_ro,
 720        Opt_barrier, Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
 721        Opt_discard, Opt_nodiscard, Opt_err,
 722};
 723
 724static match_table_t tokens = {
 725        {Opt_err_cont, "errors=continue"},
 726        {Opt_err_panic, "errors=panic"},
 727        {Opt_err_ro, "errors=remount-ro"},
 728        {Opt_barrier, "barrier"},
 729        {Opt_nobarrier, "nobarrier"},
 730        {Opt_snapshot, "cp=%u"},
 731        {Opt_order, "order=%s"},
 732        {Opt_norecovery, "norecovery"},
 733        {Opt_discard, "discard"},
 734        {Opt_nodiscard, "nodiscard"},
 735        {Opt_err, NULL}
 736};
 737
 738static int parse_options(char *options, struct super_block *sb, int is_remount)
 739{
 740        struct the_nilfs *nilfs = sb->s_fs_info;
 741        char *p;
 742        substring_t args[MAX_OPT_ARGS];
 743
 744        if (!options)
 745                return 1;
 746
 747        while ((p = strsep(&options, ",")) != NULL) {
 748                int token;
 749                if (!*p)
 750                        continue;
 751
 752                token = match_token(p, tokens, args);
 753                switch (token) {
 754                case Opt_barrier:
 755                        nilfs_set_opt(nilfs, BARRIER);
 756                        break;
 757                case Opt_nobarrier:
 758                        nilfs_clear_opt(nilfs, BARRIER);
 759                        break;
 760                case Opt_order:
 761                        if (strcmp(args[0].from, "relaxed") == 0)
 762                                /* Ordered data semantics */
 763                                nilfs_clear_opt(nilfs, STRICT_ORDER);
 764                        else if (strcmp(args[0].from, "strict") == 0)
 765                                /* Strict in-order semantics */
 766                                nilfs_set_opt(nilfs, STRICT_ORDER);
 767                        else
 768                                return 0;
 769                        break;
 770                case Opt_err_panic:
 771                        nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_PANIC);
 772                        break;
 773                case Opt_err_ro:
 774                        nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_RO);
 775                        break;
 776                case Opt_err_cont:
 777                        nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_CONT);
 778                        break;
 779                case Opt_snapshot:
 780                        if (is_remount) {
 781                                printk(KERN_ERR
 782                                       "NILFS: \"%s\" option is invalid "
 783                                       "for remount.\n", p);
 784                                return 0;
 785                        }
 786                        break;
 787                case Opt_norecovery:
 788                        nilfs_set_opt(nilfs, NORECOVERY);
 789                        break;
 790                case Opt_discard:
 791                        nilfs_set_opt(nilfs, DISCARD);
 792                        break;
 793                case Opt_nodiscard:
 794                        nilfs_clear_opt(nilfs, DISCARD);
 795                        break;
 796                default:
 797                        printk(KERN_ERR
 798                               "NILFS: Unrecognized mount option \"%s\"\n", p);
 799                        return 0;
 800                }
 801        }
 802        return 1;
 803}
 804
 805static inline void
 806nilfs_set_default_options(struct super_block *sb,
 807                          struct nilfs_super_block *sbp)
 808{
 809        struct the_nilfs *nilfs = sb->s_fs_info;
 810
 811        nilfs->ns_mount_opt =
 812                NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
 813}
 814
 815static int nilfs_setup_super(struct super_block *sb, int is_mount)
 816{
 817        struct the_nilfs *nilfs = sb->s_fs_info;
 818        struct nilfs_super_block **sbp;
 819        int max_mnt_count;
 820        int mnt_count;
 821
 822        /* nilfs->ns_sem must be locked by the caller. */
 823        sbp = nilfs_prepare_super(sb, 0);
 824        if (!sbp)
 825                return -EIO;
 826
 827        if (!is_mount)
 828                goto skip_mount_setup;
 829
 830        max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
 831        mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
 832
 833        if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
 834                printk(KERN_WARNING
 835                       "NILFS warning: mounting fs with errors\n");
 836#if 0
 837        } else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
 838                printk(KERN_WARNING
 839                       "NILFS warning: maximal mount count reached\n");
 840#endif
 841        }
 842        if (!max_mnt_count)
 843                sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
 844
 845        sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
 846        sbp[0]->s_mtime = cpu_to_le64(get_seconds());
 847
 848skip_mount_setup:
 849        sbp[0]->s_state =
 850                cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
 851        /* synchronize sbp[1] with sbp[0] */
 852        if (sbp[1])
 853                memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 854        return nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
 855}
 856
 857struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
 858                                                 u64 pos, int blocksize,
 859                                                 struct buffer_head **pbh)
 860{
 861        unsigned long long sb_index = pos;
 862        unsigned long offset;
 863
 864        offset = do_div(sb_index, blocksize);
 865        *pbh = sb_bread(sb, sb_index);
 866        if (!*pbh)
 867                return NULL;
 868        return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
 869}
 870
 871int nilfs_store_magic_and_option(struct super_block *sb,
 872                                 struct nilfs_super_block *sbp,
 873                                 char *data)
 874{
 875        struct the_nilfs *nilfs = sb->s_fs_info;
 876
 877        sb->s_magic = le16_to_cpu(sbp->s_magic);
 878
 879        /* FS independent flags */
 880#ifdef NILFS_ATIME_DISABLE
 881        sb->s_flags |= MS_NOATIME;
 882#endif
 883
 884        nilfs_set_default_options(sb, sbp);
 885
 886        nilfs->ns_resuid = le16_to_cpu(sbp->s_def_resuid);
 887        nilfs->ns_resgid = le16_to_cpu(sbp->s_def_resgid);
 888        nilfs->ns_interval = le32_to_cpu(sbp->s_c_interval);
 889        nilfs->ns_watermark = le32_to_cpu(sbp->s_c_block_max);
 890
 891        return !parse_options(data, sb, 0) ? -EINVAL : 0 ;
 892}
 893
 894int nilfs_check_feature_compatibility(struct super_block *sb,
 895                                      struct nilfs_super_block *sbp)
 896{
 897        __u64 features;
 898
 899        features = le64_to_cpu(sbp->s_feature_incompat) &
 900                ~NILFS_FEATURE_INCOMPAT_SUPP;
 901        if (features) {
 902                printk(KERN_ERR "NILFS: couldn't mount because of unsupported "
 903                       "optional features (%llx)\n",
 904                       (unsigned long long)features);
 905                return -EINVAL;
 906        }
 907        features = le64_to_cpu(sbp->s_feature_compat_ro) &
 908                ~NILFS_FEATURE_COMPAT_RO_SUPP;
 909        if (!(sb->s_flags & MS_RDONLY) && features) {
 910                printk(KERN_ERR "NILFS: couldn't mount RDWR because of "
 911                       "unsupported optional features (%llx)\n",
 912                       (unsigned long long)features);
 913                return -EINVAL;
 914        }
 915        return 0;
 916}
 917
 918static int nilfs_get_root_dentry(struct super_block *sb,
 919                                 struct nilfs_root *root,
 920                                 struct dentry **root_dentry)
 921{
 922        struct inode *inode;
 923        struct dentry *dentry;
 924        int ret = 0;
 925
 926        inode = nilfs_iget(sb, root, NILFS_ROOT_INO);
 927        if (IS_ERR(inode)) {
 928                printk(KERN_ERR "NILFS: get root inode failed\n");
 929                ret = PTR_ERR(inode);
 930                goto out;
 931        }
 932        if (!S_ISDIR(inode->i_mode) || !inode->i_blocks || !inode->i_size) {
 933                iput(inode);
 934                printk(KERN_ERR "NILFS: corrupt root inode.\n");
 935                ret = -EINVAL;
 936                goto out;
 937        }
 938
 939        if (root->cno == NILFS_CPTREE_CURRENT_CNO) {
 940                dentry = d_find_alias(inode);
 941                if (!dentry) {
 942                        dentry = d_make_root(inode);
 943                        if (!dentry) {
 944                                ret = -ENOMEM;
 945                                goto failed_dentry;
 946                        }
 947                } else {
 948                        iput(inode);
 949                }
 950        } else {
 951                dentry = d_obtain_root(inode);
 952                if (IS_ERR(dentry)) {
 953                        ret = PTR_ERR(dentry);
 954                        goto failed_dentry;
 955                }
 956        }
 957        *root_dentry = dentry;
 958 out:
 959        return ret;
 960
 961 failed_dentry:
 962        printk(KERN_ERR "NILFS: get root dentry failed\n");
 963        goto out;
 964}
 965
 966static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
 967                                 struct dentry **root_dentry)
 968{
 969        struct the_nilfs *nilfs = s->s_fs_info;
 970        struct nilfs_root *root;
 971        int ret;
 972
 973        mutex_lock(&nilfs->ns_snapshot_mount_mutex);
 974
 975        down_read(&nilfs->ns_segctor_sem);
 976        ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
 977        up_read(&nilfs->ns_segctor_sem);
 978        if (ret < 0) {
 979                ret = (ret == -ENOENT) ? -EINVAL : ret;
 980                goto out;
 981        } else if (!ret) {
 982                printk(KERN_ERR "NILFS: The specified checkpoint is "
 983                       "not a snapshot (checkpoint number=%llu).\n",
 984                       (unsigned long long)cno);
 985                ret = -EINVAL;
 986                goto out;
 987        }
 988
 989        ret = nilfs_attach_checkpoint(s, cno, false, &root);
 990        if (ret) {
 991                printk(KERN_ERR "NILFS: error loading snapshot "
 992                       "(checkpoint number=%llu).\n",
 993               (unsigned long long)cno);
 994                goto out;
 995        }
 996        ret = nilfs_get_root_dentry(s, root, root_dentry);
 997        nilfs_put_root(root);
 998 out:
 999        mutex_unlock(&nilfs->ns_snapshot_mount_mutex);
1000        return ret;
1001}
1002
1003/**
1004 * nilfs_tree_is_busy() - try to shrink dentries of a checkpoint
1005 * @root_dentry: root dentry of the tree to be shrunk
1006 *
1007 * This function returns true if the tree was in-use.
1008 */
1009static bool nilfs_tree_is_busy(struct dentry *root_dentry)
1010{
1011        shrink_dcache_parent(root_dentry);
1012        return d_count(root_dentry) > 1;
1013}
1014
1015int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno)
1016{
1017        struct the_nilfs *nilfs = sb->s_fs_info;
1018        struct nilfs_root *root;
1019        struct inode *inode;
1020        struct dentry *dentry;
1021        int ret;
1022
1023        if (cno < 0 || cno > nilfs->ns_cno)
1024                return false;
1025
1026        if (cno >= nilfs_last_cno(nilfs))
1027                return true;    /* protect recent checkpoints */
1028
1029        ret = false;
1030        root = nilfs_lookup_root(nilfs, cno);
1031        if (root) {
1032                inode = nilfs_ilookup(sb, root, NILFS_ROOT_INO);
1033                if (inode) {
1034                        dentry = d_find_alias(inode);
1035                        if (dentry) {
1036                                ret = nilfs_tree_is_busy(dentry);
1037                                dput(dentry);
1038                        }
1039                        iput(inode);
1040                }
1041                nilfs_put_root(root);
1042        }
1043        return ret;
1044}
1045
1046/**
1047 * nilfs_fill_super() - initialize a super block instance
1048 * @sb: super_block
1049 * @data: mount options
1050 * @silent: silent mode flag
1051 *
1052 * This function is called exclusively by nilfs->ns_mount_mutex.
1053 * So, the recovery process is protected from other simultaneous mounts.
1054 */
1055static int
1056nilfs_fill_super(struct super_block *sb, void *data, int silent)
1057{
1058        struct the_nilfs *nilfs;
1059        struct nilfs_root *fsroot;
1060        struct backing_dev_info *bdi;
1061        __u64 cno;
1062        int err;
1063
1064        nilfs = alloc_nilfs(sb->s_bdev);
1065        if (!nilfs)
1066                return -ENOMEM;
1067
1068        sb->s_fs_info = nilfs;
1069
1070        err = init_nilfs(nilfs, sb, (char *)data);
1071        if (err)
1072                goto failed_nilfs;
1073
1074        sb->s_op = &nilfs_sops;
1075        sb->s_export_op = &nilfs_export_ops;
1076        sb->s_root = NULL;
1077        sb->s_time_gran = 1;
1078        sb->s_max_links = NILFS_LINK_MAX;
1079
1080        bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
1081        sb->s_bdi = bdi ? : &default_backing_dev_info;
1082
1083        err = load_nilfs(nilfs, sb);
1084        if (err)
1085                goto failed_nilfs;
1086
1087        cno = nilfs_last_cno(nilfs);
1088        err = nilfs_attach_checkpoint(sb, cno, true, &fsroot);
1089        if (err) {
1090                printk(KERN_ERR "NILFS: error loading last checkpoint "
1091                       "(checkpoint number=%llu).\n", (unsigned long long)cno);
1092                goto failed_unload;
1093        }
1094
1095        if (!(sb->s_flags & MS_RDONLY)) {
1096                err = nilfs_attach_log_writer(sb, fsroot);
1097                if (err)
1098                        goto failed_checkpoint;
1099        }
1100
1101        err = nilfs_get_root_dentry(sb, fsroot, &sb->s_root);
1102        if (err)
1103                goto failed_segctor;
1104
1105        nilfs_put_root(fsroot);
1106
1107        if (!(sb->s_flags & MS_RDONLY)) {
1108                down_write(&nilfs->ns_sem);
1109                nilfs_setup_super(sb, true);
1110                up_write(&nilfs->ns_sem);
1111        }
1112
1113        return 0;
1114
1115 failed_segctor:
1116        nilfs_detach_log_writer(sb);
1117
1118 failed_checkpoint:
1119        nilfs_put_root(fsroot);
1120
1121 failed_unload:
1122        iput(nilfs->ns_sufile);
1123        iput(nilfs->ns_cpfile);
1124        iput(nilfs->ns_dat);
1125
1126 failed_nilfs:
1127        destroy_nilfs(nilfs);
1128        return err;
1129}
1130
1131static int nilfs_remount(struct super_block *sb, int *flags, char *data)
1132{
1133        struct the_nilfs *nilfs = sb->s_fs_info;
1134        unsigned long old_sb_flags;
1135        unsigned long old_mount_opt;
1136        int err;
1137
1138        sync_filesystem(sb);
1139        old_sb_flags = sb->s_flags;
1140        old_mount_opt = nilfs->ns_mount_opt;
1141
1142        if (!parse_options(data, sb, 1)) {
1143                err = -EINVAL;
1144                goto restore_opts;
1145        }
1146        sb->s_flags = (sb->s_flags & ~MS_POSIXACL);
1147
1148        err = -EINVAL;
1149
1150        if (!nilfs_valid_fs(nilfs)) {
1151                printk(KERN_WARNING "NILFS (device %s): couldn't "
1152                       "remount because the filesystem is in an "
1153                       "incomplete recovery state.\n", sb->s_id);
1154                goto restore_opts;
1155        }
1156
1157        if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1158                goto out;
1159        if (*flags & MS_RDONLY) {
1160                /* Shutting down log writer */
1161                nilfs_detach_log_writer(sb);
1162                sb->s_flags |= MS_RDONLY;
1163
1164                /*
1165                 * Remounting a valid RW partition RDONLY, so set
1166                 * the RDONLY flag and then mark the partition as valid again.
1167                 */
1168                down_write(&nilfs->ns_sem);
1169                nilfs_cleanup_super(sb);
1170                up_write(&nilfs->ns_sem);
1171        } else {
1172                __u64 features;
1173                struct nilfs_root *root;
1174
1175                /*
1176                 * Mounting a RDONLY partition read-write, so reread and
1177                 * store the current valid flag.  (It may have been changed
1178                 * by fsck since we originally mounted the partition.)
1179                 */
1180                down_read(&nilfs->ns_sem);
1181                features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
1182                        ~NILFS_FEATURE_COMPAT_RO_SUPP;
1183                up_read(&nilfs->ns_sem);
1184                if (features) {
1185                        printk(KERN_WARNING "NILFS (device %s): couldn't "
1186                               "remount RDWR because of unsupported optional "
1187                               "features (%llx)\n",
1188                               sb->s_id, (unsigned long long)features);
1189                        err = -EROFS;
1190                        goto restore_opts;
1191                }
1192
1193                sb->s_flags &= ~MS_RDONLY;
1194
1195                root = NILFS_I(sb->s_root->d_inode)->i_root;
1196                err = nilfs_attach_log_writer(sb, root);
1197                if (err)
1198                        goto restore_opts;
1199
1200                down_write(&nilfs->ns_sem);
1201                nilfs_setup_super(sb, true);
1202                up_write(&nilfs->ns_sem);
1203        }
1204 out:
1205        return 0;
1206
1207 restore_opts:
1208        sb->s_flags = old_sb_flags;
1209        nilfs->ns_mount_opt = old_mount_opt;
1210        return err;
1211}
1212
1213struct nilfs_super_data {
1214        struct block_device *bdev;
1215        __u64 cno;
1216        int flags;
1217};
1218
1219/**
1220 * nilfs_identify - pre-read mount options needed to identify mount instance
1221 * @data: mount options
1222 * @sd: nilfs_super_data
1223 */
1224static int nilfs_identify(char *data, struct nilfs_super_data *sd)
1225{
1226        char *p, *options = data;
1227        substring_t args[MAX_OPT_ARGS];
1228        int token;
1229        int ret = 0;
1230
1231        do {
1232                p = strsep(&options, ",");
1233                if (p != NULL && *p) {
1234                        token = match_token(p, tokens, args);
1235                        if (token == Opt_snapshot) {
1236                                if (!(sd->flags & MS_RDONLY)) {
1237                                        ret++;
1238                                } else {
1239                                        sd->cno = simple_strtoull(args[0].from,
1240                                                                  NULL, 0);
1241                                        /*
1242                                         * No need to see the end pointer;
1243                                         * match_token() has done syntax
1244                                         * checking.
1245                                         */
1246                                        if (sd->cno == 0)
1247                                                ret++;
1248                                }
1249                        }
1250                        if (ret)
1251                                printk(KERN_ERR
1252                                       "NILFS: invalid mount option: %s\n", p);
1253                }
1254                if (!options)
1255                        break;
1256                BUG_ON(options == data);
1257                *(options - 1) = ',';
1258        } while (!ret);
1259        return ret;
1260}
1261
1262static int nilfs_set_bdev_super(struct super_block *s, void *data)
1263{
1264        s->s_bdev = data;
1265        s->s_dev = s->s_bdev->bd_dev;
1266        return 0;
1267}
1268
1269static int nilfs_test_bdev_super(struct super_block *s, void *data)
1270{
1271        return (void *)s->s_bdev == data;
1272}
1273
1274static struct dentry *
1275nilfs_mount(struct file_system_type *fs_type, int flags,
1276             const char *dev_name, void *data)
1277{
1278        struct nilfs_super_data sd;
1279        struct super_block *s;
1280        fmode_t mode = FMODE_READ | FMODE_EXCL;
1281        struct dentry *root_dentry;
1282        int err, s_new = false;
1283
1284        if (!(flags & MS_RDONLY))
1285                mode |= FMODE_WRITE;
1286
1287        sd.bdev = blkdev_get_by_path(dev_name, mode, fs_type);
1288        if (IS_ERR(sd.bdev))
1289                return ERR_CAST(sd.bdev);
1290
1291        sd.cno = 0;
1292        sd.flags = flags;
1293        if (nilfs_identify((char *)data, &sd)) {
1294                err = -EINVAL;
1295                goto failed;
1296        }
1297
1298        /*
1299         * once the super is inserted into the list by sget, s_umount
1300         * will protect the lockfs code from trying to start a snapshot
1301         * while we are mounting
1302         */
1303        mutex_lock(&sd.bdev->bd_fsfreeze_mutex);
1304        if (sd.bdev->bd_fsfreeze_count > 0) {
1305                mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1306                err = -EBUSY;
1307                goto failed;
1308        }
1309        s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, flags,
1310                 sd.bdev);
1311        mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1312        if (IS_ERR(s)) {
1313                err = PTR_ERR(s);
1314                goto failed;
1315        }
1316
1317        if (!s->s_root) {
1318                char b[BDEVNAME_SIZE];
1319
1320                s_new = true;
1321
1322                /* New superblock instance created */
1323                s->s_mode = mode;
1324                strlcpy(s->s_id, bdevname(sd.bdev, b), sizeof(s->s_id));
1325                sb_set_blocksize(s, block_size(sd.bdev));
1326
1327                err = nilfs_fill_super(s, data, flags & MS_SILENT ? 1 : 0);
1328                if (err)
1329                        goto failed_super;
1330
1331                s->s_flags |= MS_ACTIVE;
1332        } else if (!sd.cno) {
1333                if (nilfs_tree_is_busy(s->s_root)) {
1334                        if ((flags ^ s->s_flags) & MS_RDONLY) {
1335                                printk(KERN_ERR "NILFS: the device already "
1336                                       "has a %s mount.\n",
1337                                       (s->s_flags & MS_RDONLY) ?
1338                                       "read-only" : "read/write");
1339                                err = -EBUSY;
1340                                goto failed_super;
1341                        }
1342                } else {
1343                        /*
1344                         * Try remount to setup mount states if the current
1345                         * tree is not mounted and only snapshots use this sb.
1346                         */
1347                        err = nilfs_remount(s, &flags, data);
1348                        if (err)
1349                                goto failed_super;
1350                }
1351        }
1352
1353        if (sd.cno) {
1354                err = nilfs_attach_snapshot(s, sd.cno, &root_dentry);
1355                if (err)
1356                        goto failed_super;
1357        } else {
1358                root_dentry = dget(s->s_root);
1359        }
1360
1361        if (!s_new)
1362                blkdev_put(sd.bdev, mode);
1363
1364        return root_dentry;
1365
1366 failed_super:
1367        deactivate_locked_super(s);
1368
1369 failed:
1370        if (!s_new)
1371                blkdev_put(sd.bdev, mode);
1372        return ERR_PTR(err);
1373}
1374
1375struct file_system_type nilfs_fs_type = {
1376        .owner    = THIS_MODULE,
1377        .name     = "nilfs2",
1378        .mount    = nilfs_mount,
1379        .kill_sb  = kill_block_super,
1380        .fs_flags = FS_REQUIRES_DEV,
1381};
1382MODULE_ALIAS_FS("nilfs2");
1383
1384static void nilfs_inode_init_once(void *obj)
1385{
1386        struct nilfs_inode_info *ii = obj;
1387
1388        INIT_LIST_HEAD(&ii->i_dirty);
1389#ifdef CONFIG_NILFS_XATTR
1390        init_rwsem(&ii->xattr_sem);
1391#endif
1392        address_space_init_once(&ii->i_btnode_cache);
1393        ii->i_bmap = &ii->i_bmap_data;
1394        inode_init_once(&ii->vfs_inode);
1395}
1396
1397static void nilfs_segbuf_init_once(void *obj)
1398{
1399        memset(obj, 0, sizeof(struct nilfs_segment_buffer));
1400}
1401
1402static void nilfs_destroy_cachep(void)
1403{
1404        /*
1405         * Make sure all delayed rcu free inodes are flushed before we
1406         * destroy cache.
1407         */
1408        rcu_barrier();
1409
1410        if (nilfs_inode_cachep)
1411                kmem_cache_destroy(nilfs_inode_cachep);
1412        if (nilfs_transaction_cachep)
1413                kmem_cache_destroy(nilfs_transaction_cachep);
1414        if (nilfs_segbuf_cachep)
1415                kmem_cache_destroy(nilfs_segbuf_cachep);
1416        if (nilfs_btree_path_cache)
1417                kmem_cache_destroy(nilfs_btree_path_cache);
1418}
1419
1420static int __init nilfs_init_cachep(void)
1421{
1422        nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
1423                        sizeof(struct nilfs_inode_info), 0,
1424                        SLAB_RECLAIM_ACCOUNT, nilfs_inode_init_once);
1425        if (!nilfs_inode_cachep)
1426                goto fail;
1427
1428        nilfs_transaction_cachep = kmem_cache_create("nilfs2_transaction_cache",
1429                        sizeof(struct nilfs_transaction_info), 0,
1430                        SLAB_RECLAIM_ACCOUNT, NULL);
1431        if (!nilfs_transaction_cachep)
1432                goto fail;
1433
1434        nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache",
1435                        sizeof(struct nilfs_segment_buffer), 0,
1436                        SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once);
1437        if (!nilfs_segbuf_cachep)
1438                goto fail;
1439
1440        nilfs_btree_path_cache = kmem_cache_create("nilfs2_btree_path_cache",
1441                        sizeof(struct nilfs_btree_path) * NILFS_BTREE_LEVEL_MAX,
1442                        0, 0, NULL);
1443        if (!nilfs_btree_path_cache)
1444                goto fail;
1445
1446        return 0;
1447
1448fail:
1449        nilfs_destroy_cachep();
1450        return -ENOMEM;
1451}
1452
1453static int __init init_nilfs_fs(void)
1454{
1455        int err;
1456
1457        err = nilfs_init_cachep();
1458        if (err)
1459                goto fail;
1460
1461        err = nilfs_sysfs_init();
1462        if (err)
1463                goto free_cachep;
1464
1465        err = register_filesystem(&nilfs_fs_type);
1466        if (err)
1467                goto deinit_sysfs_entry;
1468
1469        printk(KERN_INFO "NILFS version 2 loaded\n");
1470        return 0;
1471
1472deinit_sysfs_entry:
1473        nilfs_sysfs_exit();
1474free_cachep:
1475        nilfs_destroy_cachep();
1476fail:
1477        return err;
1478}
1479
1480static void __exit exit_nilfs_fs(void)
1481{
1482        nilfs_destroy_cachep();
1483        nilfs_sysfs_exit();
1484        unregister_filesystem(&nilfs_fs_type);
1485}
1486
1487module_init(init_nilfs_fs)
1488module_exit(exit_nilfs_fs)
1489