linux/fs/nilfs2/super.c
<<
>>
Prefs
   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * super.c - NILFS module and super block management.
   4 *
   5 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   6 *
   7 * Written by Ryusuke Konishi.
   8 */
   9/*
  10 *  linux/fs/ext2/super.c
  11 *
  12 * Copyright (C) 1992, 1993, 1994, 1995
  13 * Remy Card (card@masi.ibp.fr)
  14 * Laboratoire MASI - Institut Blaise Pascal
  15 * Universite Pierre et Marie Curie (Paris VI)
  16 *
  17 *  from
  18 *
  19 *  linux/fs/minix/inode.c
  20 *
  21 *  Copyright (C) 1991, 1992  Linus Torvalds
  22 *
  23 *  Big-endian to little-endian byte-swapping/bitmaps by
  24 *        David S. Miller (davem@caip.rutgers.edu), 1995
  25 */
  26
  27#include <linux/module.h>
  28#include <linux/string.h>
  29#include <linux/slab.h>
  30#include <linux/init.h>
  31#include <linux/blkdev.h>
  32#include <linux/parser.h>
  33#include <linux/crc32.h>
  34#include <linux/vfs.h>
  35#include <linux/writeback.h>
  36#include <linux/seq_file.h>
  37#include <linux/mount.h>
  38#include "nilfs.h"
  39#include "export.h"
  40#include "mdt.h"
  41#include "alloc.h"
  42#include "btree.h"
  43#include "btnode.h"
  44#include "page.h"
  45#include "cpfile.h"
  46#include "sufile.h" /* nilfs_sufile_resize(), nilfs_sufile_set_alloc_range() */
  47#include "ifile.h"
  48#include "dat.h"
  49#include "segment.h"
  50#include "segbuf.h"
  51
  52MODULE_AUTHOR("NTT Corp.");
  53MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
  54                   "(NILFS)");
  55MODULE_LICENSE("GPL");
  56
  57static struct kmem_cache *nilfs_inode_cachep;
  58struct kmem_cache *nilfs_transaction_cachep;
  59struct kmem_cache *nilfs_segbuf_cachep;
  60struct kmem_cache *nilfs_btree_path_cache;
  61
  62static int nilfs_setup_super(struct super_block *sb, int is_mount);
  63static int nilfs_remount(struct super_block *sb, int *flags, char *data);
  64
  65void __nilfs_msg(struct super_block *sb, const char *fmt, ...)
  66{
  67        struct va_format vaf;
  68        va_list args;
  69        int level;
  70
  71        va_start(args, fmt);
  72
  73        level = printk_get_level(fmt);
  74        vaf.fmt = printk_skip_level(fmt);
  75        vaf.va = &args;
  76
  77        if (sb)
  78                printk("%c%cNILFS (%s): %pV\n",
  79                       KERN_SOH_ASCII, level, sb->s_id, &vaf);
  80        else
  81                printk("%c%cNILFS: %pV\n",
  82                       KERN_SOH_ASCII, level, &vaf);
  83
  84        va_end(args);
  85}
  86
  87static void nilfs_set_error(struct super_block *sb)
  88{
  89        struct the_nilfs *nilfs = sb->s_fs_info;
  90        struct nilfs_super_block **sbp;
  91
  92        down_write(&nilfs->ns_sem);
  93        if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
  94                nilfs->ns_mount_state |= NILFS_ERROR_FS;
  95                sbp = nilfs_prepare_super(sb, 0);
  96                if (likely(sbp)) {
  97                        sbp[0]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
  98                        if (sbp[1])
  99                                sbp[1]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
 100                        nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
 101                }
 102        }
 103        up_write(&nilfs->ns_sem);
 104}
 105
 106/**
 107 * __nilfs_error() - report failure condition on a filesystem
 108 *
 109 * __nilfs_error() sets an ERROR_FS flag on the superblock as well as
 110 * reporting an error message.  This function should be called when
 111 * NILFS detects incoherences or defects of meta data on disk.
 112 *
 113 * This implements the body of nilfs_error() macro.  Normally,
 114 * nilfs_error() should be used.  As for sustainable errors such as a
 115 * single-shot I/O error, nilfs_err() should be used instead.
 116 *
 117 * Callers should not add a trailing newline since this will do it.
 118 */
 119void __nilfs_error(struct super_block *sb, const char *function,
 120                   const char *fmt, ...)
 121{
 122        struct the_nilfs *nilfs = sb->s_fs_info;
 123        struct va_format vaf;
 124        va_list args;
 125
 126        va_start(args, fmt);
 127
 128        vaf.fmt = fmt;
 129        vaf.va = &args;
 130
 131        printk(KERN_CRIT "NILFS error (device %s): %s: %pV\n",
 132               sb->s_id, function, &vaf);
 133
 134        va_end(args);
 135
 136        if (!sb_rdonly(sb)) {
 137                nilfs_set_error(sb);
 138
 139                if (nilfs_test_opt(nilfs, ERRORS_RO)) {
 140                        printk(KERN_CRIT "Remounting filesystem read-only\n");
 141                        sb->s_flags |= SB_RDONLY;
 142                }
 143        }
 144
 145        if (nilfs_test_opt(nilfs, ERRORS_PANIC))
 146                panic("NILFS (device %s): panic forced after error\n",
 147                      sb->s_id);
 148}
 149
 150struct inode *nilfs_alloc_inode(struct super_block *sb)
 151{
 152        struct nilfs_inode_info *ii;
 153
 154        ii = kmem_cache_alloc(nilfs_inode_cachep, GFP_NOFS);
 155        if (!ii)
 156                return NULL;
 157        ii->i_bh = NULL;
 158        ii->i_state = 0;
 159        ii->i_cno = 0;
 160        nilfs_mapping_init(&ii->i_btnode_cache, &ii->vfs_inode);
 161        return &ii->vfs_inode;
 162}
 163
 164static void nilfs_free_inode(struct inode *inode)
 165{
 166        if (nilfs_is_metadata_file_inode(inode))
 167                nilfs_mdt_destroy(inode);
 168
 169        kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
 170}
 171
 172static int nilfs_sync_super(struct super_block *sb, int flag)
 173{
 174        struct the_nilfs *nilfs = sb->s_fs_info;
 175        int err;
 176
 177 retry:
 178        set_buffer_dirty(nilfs->ns_sbh[0]);
 179        if (nilfs_test_opt(nilfs, BARRIER)) {
 180                err = __sync_dirty_buffer(nilfs->ns_sbh[0],
 181                                          REQ_SYNC | REQ_PREFLUSH | REQ_FUA);
 182        } else {
 183                err = sync_dirty_buffer(nilfs->ns_sbh[0]);
 184        }
 185
 186        if (unlikely(err)) {
 187                nilfs_err(sb, "unable to write superblock: err=%d", err);
 188                if (err == -EIO && nilfs->ns_sbh[1]) {
 189                        /*
 190                         * sbp[0] points to newer log than sbp[1],
 191                         * so copy sbp[0] to sbp[1] to take over sbp[0].
 192                         */
 193                        memcpy(nilfs->ns_sbp[1], nilfs->ns_sbp[0],
 194                               nilfs->ns_sbsize);
 195                        nilfs_fall_back_super_block(nilfs);
 196                        goto retry;
 197                }
 198        } else {
 199                struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
 200
 201                nilfs->ns_sbwcount++;
 202
 203                /*
 204                 * The latest segment becomes trailable from the position
 205                 * written in superblock.
 206                 */
 207                clear_nilfs_discontinued(nilfs);
 208
 209                /* update GC protection for recent segments */
 210                if (nilfs->ns_sbh[1]) {
 211                        if (flag == NILFS_SB_COMMIT_ALL) {
 212                                set_buffer_dirty(nilfs->ns_sbh[1]);
 213                                if (sync_dirty_buffer(nilfs->ns_sbh[1]) < 0)
 214                                        goto out;
 215                        }
 216                        if (le64_to_cpu(nilfs->ns_sbp[1]->s_last_cno) <
 217                            le64_to_cpu(nilfs->ns_sbp[0]->s_last_cno))
 218                                sbp = nilfs->ns_sbp[1];
 219                }
 220
 221                spin_lock(&nilfs->ns_last_segment_lock);
 222                nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
 223                spin_unlock(&nilfs->ns_last_segment_lock);
 224        }
 225 out:
 226        return err;
 227}
 228
 229void nilfs_set_log_cursor(struct nilfs_super_block *sbp,
 230                          struct the_nilfs *nilfs)
 231{
 232        sector_t nfreeblocks;
 233
 234        /* nilfs->ns_sem must be locked by the caller. */
 235        nilfs_count_free_blocks(nilfs, &nfreeblocks);
 236        sbp->s_free_blocks_count = cpu_to_le64(nfreeblocks);
 237
 238        spin_lock(&nilfs->ns_last_segment_lock);
 239        sbp->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
 240        sbp->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
 241        sbp->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
 242        spin_unlock(&nilfs->ns_last_segment_lock);
 243}
 244
 245struct nilfs_super_block **nilfs_prepare_super(struct super_block *sb,
 246                                               int flip)
 247{
 248        struct the_nilfs *nilfs = sb->s_fs_info;
 249        struct nilfs_super_block **sbp = nilfs->ns_sbp;
 250
 251        /* nilfs->ns_sem must be locked by the caller. */
 252        if (sbp[0]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 253                if (sbp[1] &&
 254                    sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC)) {
 255                        memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
 256                } else {
 257                        nilfs_crit(sb, "superblock broke");
 258                        return NULL;
 259                }
 260        } else if (sbp[1] &&
 261                   sbp[1]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 262                memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 263        }
 264
 265        if (flip && sbp[1])
 266                nilfs_swap_super_block(nilfs);
 267
 268        return sbp;
 269}
 270
 271int nilfs_commit_super(struct super_block *sb, int flag)
 272{
 273        struct the_nilfs *nilfs = sb->s_fs_info;
 274        struct nilfs_super_block **sbp = nilfs->ns_sbp;
 275        time64_t t;
 276
 277        /* nilfs->ns_sem must be locked by the caller. */
 278        t = ktime_get_real_seconds();
 279        nilfs->ns_sbwtime = t;
 280        sbp[0]->s_wtime = cpu_to_le64(t);
 281        sbp[0]->s_sum = 0;
 282        sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 283                                             (unsigned char *)sbp[0],
 284                                             nilfs->ns_sbsize));
 285        if (flag == NILFS_SB_COMMIT_ALL && sbp[1]) {
 286                sbp[1]->s_wtime = sbp[0]->s_wtime;
 287                sbp[1]->s_sum = 0;
 288                sbp[1]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 289                                            (unsigned char *)sbp[1],
 290                                            nilfs->ns_sbsize));
 291        }
 292        clear_nilfs_sb_dirty(nilfs);
 293        nilfs->ns_flushed_device = 1;
 294        /* make sure store to ns_flushed_device cannot be reordered */
 295        smp_wmb();
 296        return nilfs_sync_super(sb, flag);
 297}
 298
 299/**
 300 * nilfs_cleanup_super() - write filesystem state for cleanup
 301 * @sb: super block instance to be unmounted or degraded to read-only
 302 *
 303 * This function restores state flags in the on-disk super block.
 304 * This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
 305 * filesystem was not clean previously.
 306 */
 307int nilfs_cleanup_super(struct super_block *sb)
 308{
 309        struct the_nilfs *nilfs = sb->s_fs_info;
 310        struct nilfs_super_block **sbp;
 311        int flag = NILFS_SB_COMMIT;
 312        int ret = -EIO;
 313
 314        sbp = nilfs_prepare_super(sb, 0);
 315        if (sbp) {
 316                sbp[0]->s_state = cpu_to_le16(nilfs->ns_mount_state);
 317                nilfs_set_log_cursor(sbp[0], nilfs);
 318                if (sbp[1] && sbp[0]->s_last_cno == sbp[1]->s_last_cno) {
 319                        /*
 320                         * make the "clean" flag also to the opposite
 321                         * super block if both super blocks point to
 322                         * the same checkpoint.
 323                         */
 324                        sbp[1]->s_state = sbp[0]->s_state;
 325                        flag = NILFS_SB_COMMIT_ALL;
 326                }
 327                ret = nilfs_commit_super(sb, flag);
 328        }
 329        return ret;
 330}
 331
 332/**
 333 * nilfs_move_2nd_super - relocate secondary super block
 334 * @sb: super block instance
 335 * @sb2off: new offset of the secondary super block (in bytes)
 336 */
 337static int nilfs_move_2nd_super(struct super_block *sb, loff_t sb2off)
 338{
 339        struct the_nilfs *nilfs = sb->s_fs_info;
 340        struct buffer_head *nsbh;
 341        struct nilfs_super_block *nsbp;
 342        sector_t blocknr, newblocknr;
 343        unsigned long offset;
 344        int sb2i;  /* array index of the secondary superblock */
 345        int ret = 0;
 346
 347        /* nilfs->ns_sem must be locked by the caller. */
 348        if (nilfs->ns_sbh[1] &&
 349            nilfs->ns_sbh[1]->b_blocknr > nilfs->ns_first_data_block) {
 350                sb2i = 1;
 351                blocknr = nilfs->ns_sbh[1]->b_blocknr;
 352        } else if (nilfs->ns_sbh[0]->b_blocknr > nilfs->ns_first_data_block) {
 353                sb2i = 0;
 354                blocknr = nilfs->ns_sbh[0]->b_blocknr;
 355        } else {
 356                sb2i = -1;
 357                blocknr = 0;
 358        }
 359        if (sb2i >= 0 && (u64)blocknr << nilfs->ns_blocksize_bits == sb2off)
 360                goto out;  /* super block location is unchanged */
 361
 362        /* Get new super block buffer */
 363        newblocknr = sb2off >> nilfs->ns_blocksize_bits;
 364        offset = sb2off & (nilfs->ns_blocksize - 1);
 365        nsbh = sb_getblk(sb, newblocknr);
 366        if (!nsbh) {
 367                nilfs_warn(sb,
 368                           "unable to move secondary superblock to block %llu",
 369                           (unsigned long long)newblocknr);
 370                ret = -EIO;
 371                goto out;
 372        }
 373        nsbp = (void *)nsbh->b_data + offset;
 374        memset(nsbp, 0, nilfs->ns_blocksize);
 375
 376        if (sb2i >= 0) {
 377                memcpy(nsbp, nilfs->ns_sbp[sb2i], nilfs->ns_sbsize);
 378                brelse(nilfs->ns_sbh[sb2i]);
 379                nilfs->ns_sbh[sb2i] = nsbh;
 380                nilfs->ns_sbp[sb2i] = nsbp;
 381        } else if (nilfs->ns_sbh[0]->b_blocknr < nilfs->ns_first_data_block) {
 382                /* secondary super block will be restored to index 1 */
 383                nilfs->ns_sbh[1] = nsbh;
 384                nilfs->ns_sbp[1] = nsbp;
 385        } else {
 386                brelse(nsbh);
 387        }
 388out:
 389        return ret;
 390}
 391
 392/**
 393 * nilfs_resize_fs - resize the filesystem
 394 * @sb: super block instance
 395 * @newsize: new size of the filesystem (in bytes)
 396 */
 397int nilfs_resize_fs(struct super_block *sb, __u64 newsize)
 398{
 399        struct the_nilfs *nilfs = sb->s_fs_info;
 400        struct nilfs_super_block **sbp;
 401        __u64 devsize, newnsegs;
 402        loff_t sb2off;
 403        int ret;
 404
 405        ret = -ERANGE;
 406        devsize = i_size_read(sb->s_bdev->bd_inode);
 407        if (newsize > devsize)
 408                goto out;
 409
 410        /*
 411         * Write lock is required to protect some functions depending
 412         * on the number of segments, the number of reserved segments,
 413         * and so forth.
 414         */
 415        down_write(&nilfs->ns_segctor_sem);
 416
 417        sb2off = NILFS_SB2_OFFSET_BYTES(newsize);
 418        newnsegs = sb2off >> nilfs->ns_blocksize_bits;
 419        do_div(newnsegs, nilfs->ns_blocks_per_segment);
 420
 421        ret = nilfs_sufile_resize(nilfs->ns_sufile, newnsegs);
 422        up_write(&nilfs->ns_segctor_sem);
 423        if (ret < 0)
 424                goto out;
 425
 426        ret = nilfs_construct_segment(sb);
 427        if (ret < 0)
 428                goto out;
 429
 430        down_write(&nilfs->ns_sem);
 431        nilfs_move_2nd_super(sb, sb2off);
 432        ret = -EIO;
 433        sbp = nilfs_prepare_super(sb, 0);
 434        if (likely(sbp)) {
 435                nilfs_set_log_cursor(sbp[0], nilfs);
 436                /*
 437                 * Drop NILFS_RESIZE_FS flag for compatibility with
 438                 * mount-time resize which may be implemented in a
 439                 * future release.
 440                 */
 441                sbp[0]->s_state = cpu_to_le16(le16_to_cpu(sbp[0]->s_state) &
 442                                              ~NILFS_RESIZE_FS);
 443                sbp[0]->s_dev_size = cpu_to_le64(newsize);
 444                sbp[0]->s_nsegments = cpu_to_le64(nilfs->ns_nsegments);
 445                if (sbp[1])
 446                        memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 447                ret = nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
 448        }
 449        up_write(&nilfs->ns_sem);
 450
 451        /*
 452         * Reset the range of allocatable segments last.  This order
 453         * is important in the case of expansion because the secondary
 454         * superblock must be protected from log write until migration
 455         * completes.
 456         */
 457        if (!ret)
 458                nilfs_sufile_set_alloc_range(nilfs->ns_sufile, 0, newnsegs - 1);
 459out:
 460        return ret;
 461}
 462
 463static void nilfs_put_super(struct super_block *sb)
 464{
 465        struct the_nilfs *nilfs = sb->s_fs_info;
 466
 467        nilfs_detach_log_writer(sb);
 468
 469        if (!sb_rdonly(sb)) {
 470                down_write(&nilfs->ns_sem);
 471                nilfs_cleanup_super(sb);
 472                up_write(&nilfs->ns_sem);
 473        }
 474
 475        iput(nilfs->ns_sufile);
 476        iput(nilfs->ns_cpfile);
 477        iput(nilfs->ns_dat);
 478
 479        destroy_nilfs(nilfs);
 480        sb->s_fs_info = NULL;
 481}
 482
 483static int nilfs_sync_fs(struct super_block *sb, int wait)
 484{
 485        struct the_nilfs *nilfs = sb->s_fs_info;
 486        struct nilfs_super_block **sbp;
 487        int err = 0;
 488
 489        /* This function is called when super block should be written back */
 490        if (wait)
 491                err = nilfs_construct_segment(sb);
 492
 493        down_write(&nilfs->ns_sem);
 494        if (nilfs_sb_dirty(nilfs)) {
 495                sbp = nilfs_prepare_super(sb, nilfs_sb_will_flip(nilfs));
 496                if (likely(sbp)) {
 497                        nilfs_set_log_cursor(sbp[0], nilfs);
 498                        nilfs_commit_super(sb, NILFS_SB_COMMIT);
 499                }
 500        }
 501        up_write(&nilfs->ns_sem);
 502
 503        if (!err)
 504                err = nilfs_flush_device(nilfs);
 505
 506        return err;
 507}
 508
 509int nilfs_attach_checkpoint(struct super_block *sb, __u64 cno, int curr_mnt,
 510                            struct nilfs_root **rootp)
 511{
 512        struct the_nilfs *nilfs = sb->s_fs_info;
 513        struct nilfs_root *root;
 514        struct nilfs_checkpoint *raw_cp;
 515        struct buffer_head *bh_cp;
 516        int err = -ENOMEM;
 517
 518        root = nilfs_find_or_create_root(
 519                nilfs, curr_mnt ? NILFS_CPTREE_CURRENT_CNO : cno);
 520        if (!root)
 521                return err;
 522
 523        if (root->ifile)
 524                goto reuse; /* already attached checkpoint */
 525
 526        down_read(&nilfs->ns_segctor_sem);
 527        err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
 528                                          &bh_cp);
 529        up_read(&nilfs->ns_segctor_sem);
 530        if (unlikely(err)) {
 531                if (err == -ENOENT || err == -EINVAL) {
 532                        nilfs_err(sb,
 533                                  "Invalid checkpoint (checkpoint number=%llu)",
 534                                  (unsigned long long)cno);
 535                        err = -EINVAL;
 536                }
 537                goto failed;
 538        }
 539
 540        err = nilfs_ifile_read(sb, root, nilfs->ns_inode_size,
 541                               &raw_cp->cp_ifile_inode, &root->ifile);
 542        if (err)
 543                goto failed_bh;
 544
 545        atomic64_set(&root->inodes_count,
 546                        le64_to_cpu(raw_cp->cp_inodes_count));
 547        atomic64_set(&root->blocks_count,
 548                        le64_to_cpu(raw_cp->cp_blocks_count));
 549
 550        nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 551
 552 reuse:
 553        *rootp = root;
 554        return 0;
 555
 556 failed_bh:
 557        nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 558 failed:
 559        nilfs_put_root(root);
 560
 561        return err;
 562}
 563
 564static int nilfs_freeze(struct super_block *sb)
 565{
 566        struct the_nilfs *nilfs = sb->s_fs_info;
 567        int err;
 568
 569        if (sb_rdonly(sb))
 570                return 0;
 571
 572        /* Mark super block clean */
 573        down_write(&nilfs->ns_sem);
 574        err = nilfs_cleanup_super(sb);
 575        up_write(&nilfs->ns_sem);
 576        return err;
 577}
 578
 579static int nilfs_unfreeze(struct super_block *sb)
 580{
 581        struct the_nilfs *nilfs = sb->s_fs_info;
 582
 583        if (sb_rdonly(sb))
 584                return 0;
 585
 586        down_write(&nilfs->ns_sem);
 587        nilfs_setup_super(sb, false);
 588        up_write(&nilfs->ns_sem);
 589        return 0;
 590}
 591
 592static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 593{
 594        struct super_block *sb = dentry->d_sb;
 595        struct nilfs_root *root = NILFS_I(d_inode(dentry))->i_root;
 596        struct the_nilfs *nilfs = root->nilfs;
 597        u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 598        unsigned long long blocks;
 599        unsigned long overhead;
 600        unsigned long nrsvblocks;
 601        sector_t nfreeblocks;
 602        u64 nmaxinodes, nfreeinodes;
 603        int err;
 604
 605        /*
 606         * Compute all of the segment blocks
 607         *
 608         * The blocks before first segment and after last segment
 609         * are excluded.
 610         */
 611        blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
 612                - nilfs->ns_first_data_block;
 613        nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
 614
 615        /*
 616         * Compute the overhead
 617         *
 618         * When distributing meta data blocks outside segment structure,
 619         * We must count them as the overhead.
 620         */
 621        overhead = 0;
 622
 623        err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
 624        if (unlikely(err))
 625                return err;
 626
 627        err = nilfs_ifile_count_free_inodes(root->ifile,
 628                                            &nmaxinodes, &nfreeinodes);
 629        if (unlikely(err)) {
 630                nilfs_warn(sb, "failed to count free inodes: err=%d", err);
 631                if (err == -ERANGE) {
 632                        /*
 633                         * If nilfs_palloc_count_max_entries() returns
 634                         * -ERANGE error code then we simply treat
 635                         * curent inodes count as maximum possible and
 636                         * zero as free inodes value.
 637                         */
 638                        nmaxinodes = atomic64_read(&root->inodes_count);
 639                        nfreeinodes = 0;
 640                        err = 0;
 641                } else
 642                        return err;
 643        }
 644
 645        buf->f_type = NILFS_SUPER_MAGIC;
 646        buf->f_bsize = sb->s_blocksize;
 647        buf->f_blocks = blocks - overhead;
 648        buf->f_bfree = nfreeblocks;
 649        buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
 650                (buf->f_bfree - nrsvblocks) : 0;
 651        buf->f_files = nmaxinodes;
 652        buf->f_ffree = nfreeinodes;
 653        buf->f_namelen = NILFS_NAME_LEN;
 654        buf->f_fsid = u64_to_fsid(id);
 655
 656        return 0;
 657}
 658
 659static int nilfs_show_options(struct seq_file *seq, struct dentry *dentry)
 660{
 661        struct super_block *sb = dentry->d_sb;
 662        struct the_nilfs *nilfs = sb->s_fs_info;
 663        struct nilfs_root *root = NILFS_I(d_inode(dentry))->i_root;
 664
 665        if (!nilfs_test_opt(nilfs, BARRIER))
 666                seq_puts(seq, ",nobarrier");
 667        if (root->cno != NILFS_CPTREE_CURRENT_CNO)
 668                seq_printf(seq, ",cp=%llu", (unsigned long long)root->cno);
 669        if (nilfs_test_opt(nilfs, ERRORS_PANIC))
 670                seq_puts(seq, ",errors=panic");
 671        if (nilfs_test_opt(nilfs, ERRORS_CONT))
 672                seq_puts(seq, ",errors=continue");
 673        if (nilfs_test_opt(nilfs, STRICT_ORDER))
 674                seq_puts(seq, ",order=strict");
 675        if (nilfs_test_opt(nilfs, NORECOVERY))
 676                seq_puts(seq, ",norecovery");
 677        if (nilfs_test_opt(nilfs, DISCARD))
 678                seq_puts(seq, ",discard");
 679
 680        return 0;
 681}
 682
 683static const struct super_operations nilfs_sops = {
 684        .alloc_inode    = nilfs_alloc_inode,
 685        .free_inode     = nilfs_free_inode,
 686        .dirty_inode    = nilfs_dirty_inode,
 687        .evict_inode    = nilfs_evict_inode,
 688        .put_super      = nilfs_put_super,
 689        .sync_fs        = nilfs_sync_fs,
 690        .freeze_fs      = nilfs_freeze,
 691        .unfreeze_fs    = nilfs_unfreeze,
 692        .statfs         = nilfs_statfs,
 693        .remount_fs     = nilfs_remount,
 694        .show_options = nilfs_show_options
 695};
 696
 697enum {
 698        Opt_err_cont, Opt_err_panic, Opt_err_ro,
 699        Opt_barrier, Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
 700        Opt_discard, Opt_nodiscard, Opt_err,
 701};
 702
 703static match_table_t tokens = {
 704        {Opt_err_cont, "errors=continue"},
 705        {Opt_err_panic, "errors=panic"},
 706        {Opt_err_ro, "errors=remount-ro"},
 707        {Opt_barrier, "barrier"},
 708        {Opt_nobarrier, "nobarrier"},
 709        {Opt_snapshot, "cp=%u"},
 710        {Opt_order, "order=%s"},
 711        {Opt_norecovery, "norecovery"},
 712        {Opt_discard, "discard"},
 713        {Opt_nodiscard, "nodiscard"},
 714        {Opt_err, NULL}
 715};
 716
 717static int parse_options(char *options, struct super_block *sb, int is_remount)
 718{
 719        struct the_nilfs *nilfs = sb->s_fs_info;
 720        char *p;
 721        substring_t args[MAX_OPT_ARGS];
 722
 723        if (!options)
 724                return 1;
 725
 726        while ((p = strsep(&options, ",")) != NULL) {
 727                int token;
 728
 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                                nilfs_err(sb,
 762                                          "\"%s\" option is invalid for remount",
 763                                          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                        nilfs_err(sb, "unrecognized mount option \"%s\"", p);
 778                        return 0;
 779                }
 780        }
 781        return 1;
 782}
 783
 784static inline void
 785nilfs_set_default_options(struct super_block *sb,
 786                          struct nilfs_super_block *sbp)
 787{
 788        struct the_nilfs *nilfs = sb->s_fs_info;
 789
 790        nilfs->ns_mount_opt =
 791                NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
 792}
 793
 794static int nilfs_setup_super(struct super_block *sb, int is_mount)
 795{
 796        struct the_nilfs *nilfs = sb->s_fs_info;
 797        struct nilfs_super_block **sbp;
 798        int max_mnt_count;
 799        int mnt_count;
 800
 801        /* nilfs->ns_sem must be locked by the caller. */
 802        sbp = nilfs_prepare_super(sb, 0);
 803        if (!sbp)
 804                return -EIO;
 805
 806        if (!is_mount)
 807                goto skip_mount_setup;
 808
 809        max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
 810        mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
 811
 812        if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
 813                nilfs_warn(sb, "mounting fs with errors");
 814#if 0
 815        } else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
 816                nilfs_warn(sb, "maximal mount count reached");
 817#endif
 818        }
 819        if (!max_mnt_count)
 820                sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
 821
 822        sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
 823        sbp[0]->s_mtime = cpu_to_le64(ktime_get_real_seconds());
 824
 825skip_mount_setup:
 826        sbp[0]->s_state =
 827                cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
 828        /* synchronize sbp[1] with sbp[0] */
 829        if (sbp[1])
 830                memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 831        return nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
 832}
 833
 834struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
 835                                                 u64 pos, int blocksize,
 836                                                 struct buffer_head **pbh)
 837{
 838        unsigned long long sb_index = pos;
 839        unsigned long offset;
 840
 841        offset = do_div(sb_index, blocksize);
 842        *pbh = sb_bread(sb, sb_index);
 843        if (!*pbh)
 844                return NULL;
 845        return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
 846}
 847
 848int nilfs_store_magic_and_option(struct super_block *sb,
 849                                 struct nilfs_super_block *sbp,
 850                                 char *data)
 851{
 852        struct the_nilfs *nilfs = sb->s_fs_info;
 853
 854        sb->s_magic = le16_to_cpu(sbp->s_magic);
 855
 856        /* FS independent flags */
 857#ifdef NILFS_ATIME_DISABLE
 858        sb->s_flags |= SB_NOATIME;
 859#endif
 860
 861        nilfs_set_default_options(sb, sbp);
 862
 863        nilfs->ns_resuid = le16_to_cpu(sbp->s_def_resuid);
 864        nilfs->ns_resgid = le16_to_cpu(sbp->s_def_resgid);
 865        nilfs->ns_interval = le32_to_cpu(sbp->s_c_interval);
 866        nilfs->ns_watermark = le32_to_cpu(sbp->s_c_block_max);
 867
 868        return !parse_options(data, sb, 0) ? -EINVAL : 0;
 869}
 870
 871int nilfs_check_feature_compatibility(struct super_block *sb,
 872                                      struct nilfs_super_block *sbp)
 873{
 874        __u64 features;
 875
 876        features = le64_to_cpu(sbp->s_feature_incompat) &
 877                ~NILFS_FEATURE_INCOMPAT_SUPP;
 878        if (features) {
 879                nilfs_err(sb,
 880                          "couldn't mount because of unsupported optional features (%llx)",
 881                          (unsigned long long)features);
 882                return -EINVAL;
 883        }
 884        features = le64_to_cpu(sbp->s_feature_compat_ro) &
 885                ~NILFS_FEATURE_COMPAT_RO_SUPP;
 886        if (!sb_rdonly(sb) && features) {
 887                nilfs_err(sb,
 888                          "couldn't mount RDWR because of unsupported optional features (%llx)",
 889                          (unsigned long long)features);
 890                return -EINVAL;
 891        }
 892        return 0;
 893}
 894
 895static int nilfs_get_root_dentry(struct super_block *sb,
 896                                 struct nilfs_root *root,
 897                                 struct dentry **root_dentry)
 898{
 899        struct inode *inode;
 900        struct dentry *dentry;
 901        int ret = 0;
 902
 903        inode = nilfs_iget(sb, root, NILFS_ROOT_INO);
 904        if (IS_ERR(inode)) {
 905                ret = PTR_ERR(inode);
 906                nilfs_err(sb, "error %d getting root inode", ret);
 907                goto out;
 908        }
 909        if (!S_ISDIR(inode->i_mode) || !inode->i_blocks || !inode->i_size) {
 910                iput(inode);
 911                nilfs_err(sb, "corrupt root inode");
 912                ret = -EINVAL;
 913                goto out;
 914        }
 915
 916        if (root->cno == NILFS_CPTREE_CURRENT_CNO) {
 917                dentry = d_find_alias(inode);
 918                if (!dentry) {
 919                        dentry = d_make_root(inode);
 920                        if (!dentry) {
 921                                ret = -ENOMEM;
 922                                goto failed_dentry;
 923                        }
 924                } else {
 925                        iput(inode);
 926                }
 927        } else {
 928                dentry = d_obtain_root(inode);
 929                if (IS_ERR(dentry)) {
 930                        ret = PTR_ERR(dentry);
 931                        goto failed_dentry;
 932                }
 933        }
 934        *root_dentry = dentry;
 935 out:
 936        return ret;
 937
 938 failed_dentry:
 939        nilfs_err(sb, "error %d getting root dentry", ret);
 940        goto out;
 941}
 942
 943static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
 944                                 struct dentry **root_dentry)
 945{
 946        struct the_nilfs *nilfs = s->s_fs_info;
 947        struct nilfs_root *root;
 948        int ret;
 949
 950        mutex_lock(&nilfs->ns_snapshot_mount_mutex);
 951
 952        down_read(&nilfs->ns_segctor_sem);
 953        ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
 954        up_read(&nilfs->ns_segctor_sem);
 955        if (ret < 0) {
 956                ret = (ret == -ENOENT) ? -EINVAL : ret;
 957                goto out;
 958        } else if (!ret) {
 959                nilfs_err(s,
 960                          "The specified checkpoint is not a snapshot (checkpoint number=%llu)",
 961                          (unsigned long long)cno);
 962                ret = -EINVAL;
 963                goto out;
 964        }
 965
 966        ret = nilfs_attach_checkpoint(s, cno, false, &root);
 967        if (ret) {
 968                nilfs_err(s,
 969                          "error %d while loading snapshot (checkpoint number=%llu)",
 970                          ret, (unsigned long long)cno);
 971                goto out;
 972        }
 973        ret = nilfs_get_root_dentry(s, root, root_dentry);
 974        nilfs_put_root(root);
 975 out:
 976        mutex_unlock(&nilfs->ns_snapshot_mount_mutex);
 977        return ret;
 978}
 979
 980/**
 981 * nilfs_tree_is_busy() - try to shrink dentries of a checkpoint
 982 * @root_dentry: root dentry of the tree to be shrunk
 983 *
 984 * This function returns true if the tree was in-use.
 985 */
 986static bool nilfs_tree_is_busy(struct dentry *root_dentry)
 987{
 988        shrink_dcache_parent(root_dentry);
 989        return d_count(root_dentry) > 1;
 990}
 991
 992int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno)
 993{
 994        struct the_nilfs *nilfs = sb->s_fs_info;
 995        struct nilfs_root *root;
 996        struct inode *inode;
 997        struct dentry *dentry;
 998        int ret;
 999
1000        if (cno > nilfs->ns_cno)
1001                return false;
1002
1003        if (cno >= nilfs_last_cno(nilfs))
1004                return true;    /* protect recent checkpoints */
1005
1006        ret = false;
1007        root = nilfs_lookup_root(nilfs, cno);
1008        if (root) {
1009                inode = nilfs_ilookup(sb, root, NILFS_ROOT_INO);
1010                if (inode) {
1011                        dentry = d_find_alias(inode);
1012                        if (dentry) {
1013                                ret = nilfs_tree_is_busy(dentry);
1014                                dput(dentry);
1015                        }
1016                        iput(inode);
1017                }
1018                nilfs_put_root(root);
1019        }
1020        return ret;
1021}
1022
1023/**
1024 * nilfs_fill_super() - initialize a super block instance
1025 * @sb: super_block
1026 * @data: mount options
1027 * @silent: silent mode flag
1028 *
1029 * This function is called exclusively by nilfs->ns_mount_mutex.
1030 * So, the recovery process is protected from other simultaneous mounts.
1031 */
1032static int
1033nilfs_fill_super(struct super_block *sb, void *data, int silent)
1034{
1035        struct the_nilfs *nilfs;
1036        struct nilfs_root *fsroot;
1037        __u64 cno;
1038        int err;
1039
1040        nilfs = alloc_nilfs(sb);
1041        if (!nilfs)
1042                return -ENOMEM;
1043
1044        sb->s_fs_info = nilfs;
1045
1046        err = init_nilfs(nilfs, sb, (char *)data);
1047        if (err)
1048                goto failed_nilfs;
1049
1050        sb->s_op = &nilfs_sops;
1051        sb->s_export_op = &nilfs_export_ops;
1052        sb->s_root = NULL;
1053        sb->s_time_gran = 1;
1054        sb->s_max_links = NILFS_LINK_MAX;
1055
1056        sb->s_bdi = bdi_get(sb->s_bdev->bd_bdi);
1057
1058        err = load_nilfs(nilfs, sb);
1059        if (err)
1060                goto failed_nilfs;
1061
1062        cno = nilfs_last_cno(nilfs);
1063        err = nilfs_attach_checkpoint(sb, cno, true, &fsroot);
1064        if (err) {
1065                nilfs_err(sb,
1066                          "error %d while loading last checkpoint (checkpoint number=%llu)",
1067                          err, (unsigned long long)cno);
1068                goto failed_unload;
1069        }
1070
1071        if (!sb_rdonly(sb)) {
1072                err = nilfs_attach_log_writer(sb, fsroot);
1073                if (err)
1074                        goto failed_checkpoint;
1075        }
1076
1077        err = nilfs_get_root_dentry(sb, fsroot, &sb->s_root);
1078        if (err)
1079                goto failed_segctor;
1080
1081        nilfs_put_root(fsroot);
1082
1083        if (!sb_rdonly(sb)) {
1084                down_write(&nilfs->ns_sem);
1085                nilfs_setup_super(sb, true);
1086                up_write(&nilfs->ns_sem);
1087        }
1088
1089        return 0;
1090
1091 failed_segctor:
1092        nilfs_detach_log_writer(sb);
1093
1094 failed_checkpoint:
1095        nilfs_put_root(fsroot);
1096
1097 failed_unload:
1098        iput(nilfs->ns_sufile);
1099        iput(nilfs->ns_cpfile);
1100        iput(nilfs->ns_dat);
1101
1102 failed_nilfs:
1103        destroy_nilfs(nilfs);
1104        return err;
1105}
1106
1107static int nilfs_remount(struct super_block *sb, int *flags, char *data)
1108{
1109        struct the_nilfs *nilfs = sb->s_fs_info;
1110        unsigned long old_sb_flags;
1111        unsigned long old_mount_opt;
1112        int err;
1113
1114        sync_filesystem(sb);
1115        old_sb_flags = sb->s_flags;
1116        old_mount_opt = nilfs->ns_mount_opt;
1117
1118        if (!parse_options(data, sb, 1)) {
1119                err = -EINVAL;
1120                goto restore_opts;
1121        }
1122        sb->s_flags = (sb->s_flags & ~SB_POSIXACL);
1123
1124        err = -EINVAL;
1125
1126        if (!nilfs_valid_fs(nilfs)) {
1127                nilfs_warn(sb,
1128                           "couldn't remount because the filesystem is in an incomplete recovery state");
1129                goto restore_opts;
1130        }
1131
1132        if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
1133                goto out;
1134        if (*flags & SB_RDONLY) {
1135                /* Shutting down log writer */
1136                nilfs_detach_log_writer(sb);
1137                sb->s_flags |= SB_RDONLY;
1138
1139                /*
1140                 * Remounting a valid RW partition RDONLY, so set
1141                 * the RDONLY flag and then mark the partition as valid again.
1142                 */
1143                down_write(&nilfs->ns_sem);
1144                nilfs_cleanup_super(sb);
1145                up_write(&nilfs->ns_sem);
1146        } else {
1147                __u64 features;
1148                struct nilfs_root *root;
1149
1150                /*
1151                 * Mounting a RDONLY partition read-write, so reread and
1152                 * store the current valid flag.  (It may have been changed
1153                 * by fsck since we originally mounted the partition.)
1154                 */
1155                down_read(&nilfs->ns_sem);
1156                features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
1157                        ~NILFS_FEATURE_COMPAT_RO_SUPP;
1158                up_read(&nilfs->ns_sem);
1159                if (features) {
1160                        nilfs_warn(sb,
1161                                   "couldn't remount RDWR because of unsupported optional features (%llx)",
1162                                   (unsigned long long)features);
1163                        err = -EROFS;
1164                        goto restore_opts;
1165                }
1166
1167                sb->s_flags &= ~SB_RDONLY;
1168
1169                root = NILFS_I(d_inode(sb->s_root))->i_root;
1170                err = nilfs_attach_log_writer(sb, root);
1171                if (err)
1172                        goto restore_opts;
1173
1174                down_write(&nilfs->ns_sem);
1175                nilfs_setup_super(sb, true);
1176                up_write(&nilfs->ns_sem);
1177        }
1178 out:
1179        return 0;
1180
1181 restore_opts:
1182        sb->s_flags = old_sb_flags;
1183        nilfs->ns_mount_opt = old_mount_opt;
1184        return err;
1185}
1186
1187struct nilfs_super_data {
1188        struct block_device *bdev;
1189        __u64 cno;
1190        int flags;
1191};
1192
1193static int nilfs_parse_snapshot_option(const char *option,
1194                                       const substring_t *arg,
1195                                       struct nilfs_super_data *sd)
1196{
1197        unsigned long long val;
1198        const char *msg = NULL;
1199        int err;
1200
1201        if (!(sd->flags & SB_RDONLY)) {
1202                msg = "read-only option is not specified";
1203                goto parse_error;
1204        }
1205
1206        err = kstrtoull(arg->from, 0, &val);
1207        if (err) {
1208                if (err == -ERANGE)
1209                        msg = "too large checkpoint number";
1210                else
1211                        msg = "malformed argument";
1212                goto parse_error;
1213        } else if (val == 0) {
1214                msg = "invalid checkpoint number 0";
1215                goto parse_error;
1216        }
1217        sd->cno = val;
1218        return 0;
1219
1220parse_error:
1221        nilfs_err(NULL, "invalid option \"%s\": %s", option, msg);
1222        return 1;
1223}
1224
1225/**
1226 * nilfs_identify - pre-read mount options needed to identify mount instance
1227 * @data: mount options
1228 * @sd: nilfs_super_data
1229 */
1230static int nilfs_identify(char *data, struct nilfs_super_data *sd)
1231{
1232        char *p, *options = data;
1233        substring_t args[MAX_OPT_ARGS];
1234        int token;
1235        int ret = 0;
1236
1237        do {
1238                p = strsep(&options, ",");
1239                if (p != NULL && *p) {
1240                        token = match_token(p, tokens, args);
1241                        if (token == Opt_snapshot)
1242                                ret = nilfs_parse_snapshot_option(p, &args[0],
1243                                                                  sd);
1244                }
1245                if (!options)
1246                        break;
1247                BUG_ON(options == data);
1248                *(options - 1) = ',';
1249        } while (!ret);
1250        return ret;
1251}
1252
1253static int nilfs_set_bdev_super(struct super_block *s, void *data)
1254{
1255        s->s_bdev = data;
1256        s->s_dev = s->s_bdev->bd_dev;
1257        return 0;
1258}
1259
1260static int nilfs_test_bdev_super(struct super_block *s, void *data)
1261{
1262        return (void *)s->s_bdev == data;
1263}
1264
1265static struct dentry *
1266nilfs_mount(struct file_system_type *fs_type, int flags,
1267             const char *dev_name, void *data)
1268{
1269        struct nilfs_super_data sd;
1270        struct super_block *s;
1271        fmode_t mode = FMODE_READ | FMODE_EXCL;
1272        struct dentry *root_dentry;
1273        int err, s_new = false;
1274
1275        if (!(flags & SB_RDONLY))
1276                mode |= FMODE_WRITE;
1277
1278        sd.bdev = blkdev_get_by_path(dev_name, mode, fs_type);
1279        if (IS_ERR(sd.bdev))
1280                return ERR_CAST(sd.bdev);
1281
1282        sd.cno = 0;
1283        sd.flags = flags;
1284        if (nilfs_identify((char *)data, &sd)) {
1285                err = -EINVAL;
1286                goto failed;
1287        }
1288
1289        /*
1290         * once the super is inserted into the list by sget, s_umount
1291         * will protect the lockfs code from trying to start a snapshot
1292         * while we are mounting
1293         */
1294        mutex_lock(&sd.bdev->bd_fsfreeze_mutex);
1295        if (sd.bdev->bd_fsfreeze_count > 0) {
1296                mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1297                err = -EBUSY;
1298                goto failed;
1299        }
1300        s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, flags,
1301                 sd.bdev);
1302        mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1303        if (IS_ERR(s)) {
1304                err = PTR_ERR(s);
1305                goto failed;
1306        }
1307
1308        if (!s->s_root) {
1309                s_new = true;
1310
1311                /* New superblock instance created */
1312                s->s_mode = mode;
1313                snprintf(s->s_id, sizeof(s->s_id), "%pg", sd.bdev);
1314                sb_set_blocksize(s, block_size(sd.bdev));
1315
1316                err = nilfs_fill_super(s, data, flags & SB_SILENT ? 1 : 0);
1317                if (err)
1318                        goto failed_super;
1319
1320                s->s_flags |= SB_ACTIVE;
1321        } else if (!sd.cno) {
1322                if (nilfs_tree_is_busy(s->s_root)) {
1323                        if ((flags ^ s->s_flags) & SB_RDONLY) {
1324                                nilfs_err(s,
1325                                          "the device already has a %s mount.",
1326                                          sb_rdonly(s) ? "read-only" : "read/write");
1327                                err = -EBUSY;
1328                                goto failed_super;
1329                        }
1330                } else {
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};
1370MODULE_ALIAS_FS("nilfs2");
1371
1372static void nilfs_inode_init_once(void *obj)
1373{
1374        struct nilfs_inode_info *ii = obj;
1375
1376        INIT_LIST_HEAD(&ii->i_dirty);
1377#ifdef CONFIG_NILFS_XATTR
1378        init_rwsem(&ii->xattr_sem);
1379#endif
1380        address_space_init_once(&ii->i_btnode_cache);
1381        ii->i_bmap = &ii->i_bmap_data;
1382        inode_init_once(&ii->vfs_inode);
1383}
1384
1385static void nilfs_segbuf_init_once(void *obj)
1386{
1387        memset(obj, 0, sizeof(struct nilfs_segment_buffer));
1388}
1389
1390static void nilfs_destroy_cachep(void)
1391{
1392        /*
1393         * Make sure all delayed rcu free inodes are flushed before we
1394         * destroy cache.
1395         */
1396        rcu_barrier();
1397
1398        kmem_cache_destroy(nilfs_inode_cachep);
1399        kmem_cache_destroy(nilfs_transaction_cachep);
1400        kmem_cache_destroy(nilfs_segbuf_cachep);
1401        kmem_cache_destroy(nilfs_btree_path_cache);
1402}
1403
1404static int __init nilfs_init_cachep(void)
1405{
1406        nilfs_inode_cachep = kmem_cache_create("nilfs2_inode_cache",
1407                        sizeof(struct nilfs_inode_info), 0,
1408                        SLAB_RECLAIM_ACCOUNT|SLAB_ACCOUNT,
1409                        nilfs_inode_init_once);
1410        if (!nilfs_inode_cachep)
1411                goto fail;
1412
1413        nilfs_transaction_cachep = kmem_cache_create("nilfs2_transaction_cache",
1414                        sizeof(struct nilfs_transaction_info), 0,
1415                        SLAB_RECLAIM_ACCOUNT, NULL);
1416        if (!nilfs_transaction_cachep)
1417                goto fail;
1418
1419        nilfs_segbuf_cachep = kmem_cache_create("nilfs2_segbuf_cache",
1420                        sizeof(struct nilfs_segment_buffer), 0,
1421                        SLAB_RECLAIM_ACCOUNT, nilfs_segbuf_init_once);
1422        if (!nilfs_segbuf_cachep)
1423                goto fail;
1424
1425        nilfs_btree_path_cache = kmem_cache_create("nilfs2_btree_path_cache",
1426                        sizeof(struct nilfs_btree_path) * NILFS_BTREE_LEVEL_MAX,
1427                        0, 0, NULL);
1428        if (!nilfs_btree_path_cache)
1429                goto fail;
1430
1431        return 0;
1432
1433fail:
1434        nilfs_destroy_cachep();
1435        return -ENOMEM;
1436}
1437
1438static int __init init_nilfs_fs(void)
1439{
1440        int err;
1441
1442        err = nilfs_init_cachep();
1443        if (err)
1444                goto fail;
1445
1446        err = nilfs_sysfs_init();
1447        if (err)
1448                goto free_cachep;
1449
1450        err = register_filesystem(&nilfs_fs_type);
1451        if (err)
1452                goto deinit_sysfs_entry;
1453
1454        printk(KERN_INFO "NILFS version 2 loaded\n");
1455        return 0;
1456
1457deinit_sysfs_entry:
1458        nilfs_sysfs_exit();
1459free_cachep:
1460        nilfs_destroy_cachep();
1461fail:
1462        return err;
1463}
1464
1465static void __exit exit_nilfs_fs(void)
1466{
1467        nilfs_destroy_cachep();
1468        nilfs_sysfs_exit();
1469        unregister_filesystem(&nilfs_fs_type);
1470}
1471
1472module_init(init_nilfs_fs)
1473module_exit(exit_nilfs_fs)
1474