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