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