linux/fs/nilfs2/super.c
<<
>>
Prefs
   1/*
   2 * super.c - NILFS module and super block management.
   3 *
   4 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program; if not, write to the Free Software
  18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19 *
  20 * Written by Ryusuke Konishi <ryusuke@osrg.net>
  21 */
  22/*
  23 *  linux/fs/ext2/super.c
  24 *
  25 * Copyright (C) 1992, 1993, 1994, 1995
  26 * Remy Card (card@masi.ibp.fr)
  27 * Laboratoire MASI - Institut Blaise Pascal
  28 * Universite Pierre et Marie Curie (Paris VI)
  29 *
  30 *  from
  31 *
  32 *  linux/fs/minix/inode.c
  33 *
  34 *  Copyright (C) 1991, 1992  Linus Torvalds
  35 *
  36 *  Big-endian to little-endian byte-swapping/bitmaps by
  37 *        David S. Miller (davem@caip.rutgers.edu), 1995
  38 */
  39
  40#include <linux/module.h>
  41#include <linux/string.h>
  42#include <linux/slab.h>
  43#include <linux/init.h>
  44#include <linux/blkdev.h>
  45#include <linux/parser.h>
  46#include <linux/crc32.h>
  47#include <linux/vfs.h>
  48#include <linux/writeback.h>
  49#include <linux/seq_file.h>
  50#include <linux/mount.h>
  51#include "nilfs.h"
  52#include "export.h"
  53#include "mdt.h"
  54#include "alloc.h"
  55#include "btree.h"
  56#include "btnode.h"
  57#include "page.h"
  58#include "cpfile.h"
  59#include "sufile.h" /* nilfs_sufile_resize(), nilfs_sufile_set_alloc_range() */
  60#include "ifile.h"
  61#include "dat.h"
  62#include "segment.h"
  63#include "segbuf.h"
  64
  65MODULE_AUTHOR("NTT Corp.");
  66MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
  67                   "(NILFS)");
  68MODULE_LICENSE("GPL");
  69
  70static struct kmem_cache *nilfs_inode_cachep;
  71struct kmem_cache *nilfs_transaction_cachep;
  72struct kmem_cache *nilfs_segbuf_cachep;
  73struct kmem_cache *nilfs_btree_path_cache;
  74
  75static int nilfs_setup_super(struct super_block *sb, int is_mount);
  76static int nilfs_remount(struct super_block *sb, int *flags, char *data);
  77
  78static void nilfs_set_error(struct super_block *sb)
  79{
  80        struct the_nilfs *nilfs = sb->s_fs_info;
  81        struct nilfs_super_block **sbp;
  82
  83        down_write(&nilfs->ns_sem);
  84        if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
  85                nilfs->ns_mount_state |= NILFS_ERROR_FS;
  86                sbp = nilfs_prepare_super(sb, 0);
  87                if (likely(sbp)) {
  88                        sbp[0]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
  89                        if (sbp[1])
  90                                sbp[1]->s_state |= cpu_to_le16(NILFS_ERROR_FS);
  91                        nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
  92                }
  93        }
  94        up_write(&nilfs->ns_sem);
  95}
  96
  97/**
  98 * nilfs_error() - report failure condition on a filesystem
  99 *
 100 * nilfs_error() sets an ERROR_FS flag on the superblock as well as
 101 * reporting an error message.  It should be called when NILFS detects
 102 * incoherences or defects of meta data on disk.  As for sustainable
 103 * errors such as a single-shot I/O error, nilfs_warning() or the printk()
 104 * function should be used instead.
 105 *
 106 * The segment constructor must not call this function because it can
 107 * kill itself.
 108 */
 109void nilfs_error(struct super_block *sb, const char *function,
 110                 const char *fmt, ...)
 111{
 112        struct the_nilfs *nilfs = sb->s_fs_info;
 113        struct va_format vaf;
 114        va_list args;
 115
 116        va_start(args, fmt);
 117
 118        vaf.fmt = fmt;
 119        vaf.va = &args;
 120
 121        printk(KERN_CRIT "NILFS error (device %s): %s: %pV\n",
 122               sb->s_id, function, &vaf);
 123
 124        va_end(args);
 125
 126        if (!(sb->s_flags & MS_RDONLY)) {
 127                nilfs_set_error(sb);
 128
 129                if (nilfs_test_opt(nilfs, ERRORS_RO)) {
 130                        printk(KERN_CRIT "Remounting filesystem read-only\n");
 131                        sb->s_flags |= MS_RDONLY;
 132                }
 133        }
 134
 135        if (nilfs_test_opt(nilfs, ERRORS_PANIC))
 136                panic("NILFS (device %s): panic forced after error\n",
 137                      sb->s_id);
 138}
 139
 140void nilfs_warning(struct super_block *sb, const char *function,
 141                   const char *fmt, ...)
 142{
 143        struct va_format vaf;
 144        va_list args;
 145
 146        va_start(args, fmt);
 147
 148        vaf.fmt = fmt;
 149        vaf.va = &args;
 150
 151        printk(KERN_WARNING "NILFS warning (device %s): %s: %pV\n",
 152               sb->s_id, function, &vaf);
 153
 154        va_end(args);
 155}
 156
 157
 158struct inode *nilfs_alloc_inode(struct super_block *sb)
 159{
 160        struct nilfs_inode_info *ii;
 161
 162        ii = kmem_cache_alloc(nilfs_inode_cachep, GFP_NOFS);
 163        if (!ii)
 164                return NULL;
 165        ii->i_bh = NULL;
 166        ii->i_state = 0;
 167        ii->i_cno = 0;
 168        ii->vfs_inode.i_version = 1;
 169        nilfs_mapping_init(&ii->i_btnode_cache, &ii->vfs_inode, sb->s_bdi);
 170        return &ii->vfs_inode;
 171}
 172
 173static void nilfs_i_callback(struct rcu_head *head)
 174{
 175        struct inode *inode = container_of(head, struct inode, i_rcu);
 176        struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
 177
 178        if (mdi) {
 179                kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
 180                kfree(mdi);
 181        }
 182        kmem_cache_free(nilfs_inode_cachep, NILFS_I(inode));
 183}
 184
 185void nilfs_destroy_inode(struct inode *inode)
 186{
 187        call_rcu(&inode->i_rcu, nilfs_i_callback);
 188}
 189
 190static int nilfs_sync_super(struct super_block *sb, int flag)
 191{
 192        struct the_nilfs *nilfs = sb->s_fs_info;
 193        int err;
 194
 195 retry:
 196        set_buffer_dirty(nilfs->ns_sbh[0]);
 197        if (nilfs_test_opt(nilfs, BARRIER)) {
 198                err = __sync_dirty_buffer(nilfs->ns_sbh[0],
 199                                          WRITE_SYNC | WRITE_FLUSH_FUA);
 200        } else {
 201                err = sync_dirty_buffer(nilfs->ns_sbh[0]);
 202        }
 203
 204        if (unlikely(err)) {
 205                printk(KERN_ERR
 206                       "NILFS: unable to write superblock (err=%d)\n", err);
 207                if (err == -EIO && nilfs->ns_sbh[1]) {
 208                        /*
 209                         * sbp[0] points to newer log than sbp[1],
 210                         * so copy sbp[0] to sbp[1] to take over sbp[0].
 211                         */
 212                        memcpy(nilfs->ns_sbp[1], nilfs->ns_sbp[0],
 213                               nilfs->ns_sbsize);
 214                        nilfs_fall_back_super_block(nilfs);
 215                        goto retry;
 216                }
 217        } else {
 218                struct nilfs_super_block *sbp = nilfs->ns_sbp[0];
 219
 220                nilfs->ns_sbwcount++;
 221
 222                /*
 223                 * The latest segment becomes trailable from the position
 224                 * written in superblock.
 225                 */
 226                clear_nilfs_discontinued(nilfs);
 227
 228                /* update GC protection for recent segments */
 229                if (nilfs->ns_sbh[1]) {
 230                        if (flag == NILFS_SB_COMMIT_ALL) {
 231                                set_buffer_dirty(nilfs->ns_sbh[1]);
 232                                if (sync_dirty_buffer(nilfs->ns_sbh[1]) < 0)
 233                                        goto out;
 234                        }
 235                        if (le64_to_cpu(nilfs->ns_sbp[1]->s_last_cno) <
 236                            le64_to_cpu(nilfs->ns_sbp[0]->s_last_cno))
 237                                sbp = nilfs->ns_sbp[1];
 238                }
 239
 240                spin_lock(&nilfs->ns_last_segment_lock);
 241                nilfs->ns_prot_seq = le64_to_cpu(sbp->s_last_seq);
 242                spin_unlock(&nilfs->ns_last_segment_lock);
 243        }
 244 out:
 245        return err;
 246}
 247
 248void nilfs_set_log_cursor(struct nilfs_super_block *sbp,
 249                          struct the_nilfs *nilfs)
 250{
 251        sector_t nfreeblocks;
 252
 253        /* nilfs->ns_sem must be locked by the caller. */
 254        nilfs_count_free_blocks(nilfs, &nfreeblocks);
 255        sbp->s_free_blocks_count = cpu_to_le64(nfreeblocks);
 256
 257        spin_lock(&nilfs->ns_last_segment_lock);
 258        sbp->s_last_seq = cpu_to_le64(nilfs->ns_last_seq);
 259        sbp->s_last_pseg = cpu_to_le64(nilfs->ns_last_pseg);
 260        sbp->s_last_cno = cpu_to_le64(nilfs->ns_last_cno);
 261        spin_unlock(&nilfs->ns_last_segment_lock);
 262}
 263
 264struct nilfs_super_block **nilfs_prepare_super(struct super_block *sb,
 265                                               int flip)
 266{
 267        struct the_nilfs *nilfs = sb->s_fs_info;
 268        struct nilfs_super_block **sbp = nilfs->ns_sbp;
 269
 270        /* nilfs->ns_sem must be locked by the caller. */
 271        if (sbp[0]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 272                if (sbp[1] &&
 273                    sbp[1]->s_magic == cpu_to_le16(NILFS_SUPER_MAGIC)) {
 274                        memcpy(sbp[0], sbp[1], nilfs->ns_sbsize);
 275                } else {
 276                        printk(KERN_CRIT "NILFS: superblock broke on dev %s\n",
 277                               sb->s_id);
 278                        return NULL;
 279                }
 280        } else if (sbp[1] &&
 281                   sbp[1]->s_magic != cpu_to_le16(NILFS_SUPER_MAGIC)) {
 282                        memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 283        }
 284
 285        if (flip && sbp[1])
 286                nilfs_swap_super_block(nilfs);
 287
 288        return sbp;
 289}
 290
 291int nilfs_commit_super(struct super_block *sb, int flag)
 292{
 293        struct the_nilfs *nilfs = sb->s_fs_info;
 294        struct nilfs_super_block **sbp = nilfs->ns_sbp;
 295        time_t t;
 296
 297        /* nilfs->ns_sem must be locked by the caller. */
 298        t = get_seconds();
 299        nilfs->ns_sbwtime = t;
 300        sbp[0]->s_wtime = cpu_to_le64(t);
 301        sbp[0]->s_sum = 0;
 302        sbp[0]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 303                                             (unsigned char *)sbp[0],
 304                                             nilfs->ns_sbsize));
 305        if (flag == NILFS_SB_COMMIT_ALL && sbp[1]) {
 306                sbp[1]->s_wtime = sbp[0]->s_wtime;
 307                sbp[1]->s_sum = 0;
 308                sbp[1]->s_sum = cpu_to_le32(crc32_le(nilfs->ns_crc_seed,
 309                                            (unsigned char *)sbp[1],
 310                                            nilfs->ns_sbsize));
 311        }
 312        clear_nilfs_sb_dirty(nilfs);
 313        return nilfs_sync_super(sb, flag);
 314}
 315
 316/**
 317 * nilfs_cleanup_super() - write filesystem state for cleanup
 318 * @sb: super block instance to be unmounted or degraded to read-only
 319 *
 320 * This function restores state flags in the on-disk super block.
 321 * This will set "clean" flag (i.e. NILFS_VALID_FS) unless the
 322 * filesystem was not clean previously.
 323 */
 324int nilfs_cleanup_super(struct super_block *sb)
 325{
 326        struct the_nilfs *nilfs = sb->s_fs_info;
 327        struct nilfs_super_block **sbp;
 328        int flag = NILFS_SB_COMMIT;
 329        int ret = -EIO;
 330
 331        sbp = nilfs_prepare_super(sb, 0);
 332        if (sbp) {
 333                sbp[0]->s_state = cpu_to_le16(nilfs->ns_mount_state);
 334                nilfs_set_log_cursor(sbp[0], nilfs);
 335                if (sbp[1] && sbp[0]->s_last_cno == sbp[1]->s_last_cno) {
 336                        /*
 337                         * make the "clean" flag also to the opposite
 338                         * super block if both super blocks point to
 339                         * the same checkpoint.
 340                         */
 341                        sbp[1]->s_state = sbp[0]->s_state;
 342                        flag = NILFS_SB_COMMIT_ALL;
 343                }
 344                ret = nilfs_commit_super(sb, flag);
 345        }
 346        return ret;
 347}
 348
 349/**
 350 * nilfs_move_2nd_super - relocate secondary super block
 351 * @sb: super block instance
 352 * @sb2off: new offset of the secondary super block (in bytes)
 353 */
 354static int nilfs_move_2nd_super(struct super_block *sb, loff_t sb2off)
 355{
 356        struct the_nilfs *nilfs = sb->s_fs_info;
 357        struct buffer_head *nsbh;
 358        struct nilfs_super_block *nsbp;
 359        sector_t blocknr, newblocknr;
 360        unsigned long offset;
 361        int sb2i = -1;  /* array index of the secondary superblock */
 362        int ret = 0;
 363
 364        /* nilfs->ns_sem must be locked by the caller. */
 365        if (nilfs->ns_sbh[1] &&
 366            nilfs->ns_sbh[1]->b_blocknr > nilfs->ns_first_data_block) {
 367                sb2i = 1;
 368                blocknr = nilfs->ns_sbh[1]->b_blocknr;
 369        } else if (nilfs->ns_sbh[0]->b_blocknr > nilfs->ns_first_data_block) {
 370                sb2i = 0;
 371                blocknr = nilfs->ns_sbh[0]->b_blocknr;
 372        }
 373        if (sb2i >= 0 && (u64)blocknr << nilfs->ns_blocksize_bits == sb2off)
 374                goto out;  /* super block location is unchanged */
 375
 376        /* Get new super block buffer */
 377        newblocknr = sb2off >> nilfs->ns_blocksize_bits;
 378        offset = sb2off & (nilfs->ns_blocksize - 1);
 379        nsbh = sb_getblk(sb, newblocknr);
 380        if (!nsbh) {
 381                printk(KERN_WARNING
 382                       "NILFS warning: unable to move secondary superblock "
 383                       "to block %llu\n", (unsigned long long)newblocknr);
 384                ret = -EIO;
 385                goto out;
 386        }
 387        nsbp = (void *)nsbh->b_data + offset;
 388        memset(nsbp, 0, nilfs->ns_blocksize);
 389
 390        if (sb2i >= 0) {
 391                memcpy(nsbp, nilfs->ns_sbp[sb2i], nilfs->ns_sbsize);
 392                brelse(nilfs->ns_sbh[sb2i]);
 393                nilfs->ns_sbh[sb2i] = nsbh;
 394                nilfs->ns_sbp[sb2i] = nsbp;
 395        } else if (nilfs->ns_sbh[0]->b_blocknr < nilfs->ns_first_data_block) {
 396                /* secondary super block will be restored to index 1 */
 397                nilfs->ns_sbh[1] = nsbh;
 398                nilfs->ns_sbp[1] = nsbp;
 399        } else {
 400                brelse(nsbh);
 401        }
 402out:
 403        return ret;
 404}
 405
 406/**
 407 * nilfs_resize_fs - resize the filesystem
 408 * @sb: super block instance
 409 * @newsize: new size of the filesystem (in bytes)
 410 */
 411int nilfs_resize_fs(struct super_block *sb, __u64 newsize)
 412{
 413        struct the_nilfs *nilfs = sb->s_fs_info;
 414        struct nilfs_super_block **sbp;
 415        __u64 devsize, newnsegs;
 416        loff_t sb2off;
 417        int ret;
 418
 419        ret = -ERANGE;
 420        devsize = i_size_read(sb->s_bdev->bd_inode);
 421        if (newsize > devsize)
 422                goto out;
 423
 424        /*
 425         * Write lock is required to protect some functions depending
 426         * on the number of segments, the number of reserved segments,
 427         * and so forth.
 428         */
 429        down_write(&nilfs->ns_segctor_sem);
 430
 431        sb2off = NILFS_SB2_OFFSET_BYTES(newsize);
 432        newnsegs = sb2off >> nilfs->ns_blocksize_bits;
 433        do_div(newnsegs, nilfs->ns_blocks_per_segment);
 434
 435        ret = nilfs_sufile_resize(nilfs->ns_sufile, newnsegs);
 436        up_write(&nilfs->ns_segctor_sem);
 437        if (ret < 0)
 438                goto out;
 439
 440        ret = nilfs_construct_segment(sb);
 441        if (ret < 0)
 442                goto out;
 443
 444        down_write(&nilfs->ns_sem);
 445        nilfs_move_2nd_super(sb, sb2off);
 446        ret = -EIO;
 447        sbp = nilfs_prepare_super(sb, 0);
 448        if (likely(sbp)) {
 449                nilfs_set_log_cursor(sbp[0], nilfs);
 450                /*
 451                 * Drop NILFS_RESIZE_FS flag for compatibility with
 452                 * mount-time resize which may be implemented in a
 453                 * future release.
 454                 */
 455                sbp[0]->s_state = cpu_to_le16(le16_to_cpu(sbp[0]->s_state) &
 456                                              ~NILFS_RESIZE_FS);
 457                sbp[0]->s_dev_size = cpu_to_le64(newsize);
 458                sbp[0]->s_nsegments = cpu_to_le64(nilfs->ns_nsegments);
 459                if (sbp[1])
 460                        memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 461                ret = nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
 462        }
 463        up_write(&nilfs->ns_sem);
 464
 465        /*
 466         * Reset the range of allocatable segments last.  This order
 467         * is important in the case of expansion because the secondary
 468         * superblock must be protected from log write until migration
 469         * completes.
 470         */
 471        if (!ret)
 472                nilfs_sufile_set_alloc_range(nilfs->ns_sufile, 0, newnsegs - 1);
 473out:
 474        return ret;
 475}
 476
 477static void nilfs_put_super(struct super_block *sb)
 478{
 479        struct the_nilfs *nilfs = sb->s_fs_info;
 480
 481        nilfs_detach_log_writer(sb);
 482
 483        if (!(sb->s_flags & MS_RDONLY)) {
 484                down_write(&nilfs->ns_sem);
 485                nilfs_cleanup_super(sb);
 486                up_write(&nilfs->ns_sem);
 487        }
 488
 489        iput(nilfs->ns_sufile);
 490        iput(nilfs->ns_cpfile);
 491        iput(nilfs->ns_dat);
 492
 493        destroy_nilfs(nilfs);
 494        sb->s_fs_info = NULL;
 495}
 496
 497static int nilfs_sync_fs(struct super_block *sb, int wait)
 498{
 499        struct the_nilfs *nilfs = sb->s_fs_info;
 500        struct nilfs_super_block **sbp;
 501        int err = 0;
 502
 503        /* This function is called when super block should be written back */
 504        if (wait)
 505                err = nilfs_construct_segment(sb);
 506
 507        down_write(&nilfs->ns_sem);
 508        if (nilfs_sb_dirty(nilfs)) {
 509                sbp = nilfs_prepare_super(sb, nilfs_sb_will_flip(nilfs));
 510                if (likely(sbp)) {
 511                        nilfs_set_log_cursor(sbp[0], nilfs);
 512                        nilfs_commit_super(sb, NILFS_SB_COMMIT);
 513                }
 514        }
 515        up_write(&nilfs->ns_sem);
 516
 517        return err;
 518}
 519
 520int nilfs_attach_checkpoint(struct super_block *sb, __u64 cno, int curr_mnt,
 521                            struct nilfs_root **rootp)
 522{
 523        struct the_nilfs *nilfs = sb->s_fs_info;
 524        struct nilfs_root *root;
 525        struct nilfs_checkpoint *raw_cp;
 526        struct buffer_head *bh_cp;
 527        int err = -ENOMEM;
 528
 529        root = nilfs_find_or_create_root(
 530                nilfs, curr_mnt ? NILFS_CPTREE_CURRENT_CNO : cno);
 531        if (!root)
 532                return err;
 533
 534        if (root->ifile)
 535                goto reuse; /* already attached checkpoint */
 536
 537        down_read(&nilfs->ns_segctor_sem);
 538        err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
 539                                          &bh_cp);
 540        up_read(&nilfs->ns_segctor_sem);
 541        if (unlikely(err)) {
 542                if (err == -ENOENT || err == -EINVAL) {
 543                        printk(KERN_ERR
 544                               "NILFS: Invalid checkpoint "
 545                               "(checkpoint number=%llu)\n",
 546                               (unsigned long long)cno);
 547                        err = -EINVAL;
 548                }
 549                goto failed;
 550        }
 551
 552        err = nilfs_ifile_read(sb, root, nilfs->ns_inode_size,
 553                               &raw_cp->cp_ifile_inode, &root->ifile);
 554        if (err)
 555                goto failed_bh;
 556
 557        atomic_set(&root->inodes_count, le64_to_cpu(raw_cp->cp_inodes_count));
 558        atomic_set(&root->blocks_count, le64_to_cpu(raw_cp->cp_blocks_count));
 559
 560        nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 561
 562 reuse:
 563        *rootp = root;
 564        return 0;
 565
 566 failed_bh:
 567        nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
 568 failed:
 569        nilfs_put_root(root);
 570
 571        return err;
 572}
 573
 574static int nilfs_freeze(struct super_block *sb)
 575{
 576        struct the_nilfs *nilfs = sb->s_fs_info;
 577        int err;
 578
 579        if (sb->s_flags & MS_RDONLY)
 580                return 0;
 581
 582        /* Mark super block clean */
 583        down_write(&nilfs->ns_sem);
 584        err = nilfs_cleanup_super(sb);
 585        up_write(&nilfs->ns_sem);
 586        return err;
 587}
 588
 589static int nilfs_unfreeze(struct super_block *sb)
 590{
 591        struct the_nilfs *nilfs = sb->s_fs_info;
 592
 593        if (sb->s_flags & MS_RDONLY)
 594                return 0;
 595
 596        down_write(&nilfs->ns_sem);
 597        nilfs_setup_super(sb, false);
 598        up_write(&nilfs->ns_sem);
 599        return 0;
 600}
 601
 602static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 603{
 604        struct super_block *sb = dentry->d_sb;
 605        struct nilfs_root *root = NILFS_I(dentry->d_inode)->i_root;
 606        struct the_nilfs *nilfs = root->nilfs;
 607        u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 608        unsigned long long blocks;
 609        unsigned long overhead;
 610        unsigned long nrsvblocks;
 611        sector_t nfreeblocks;
 612        int err;
 613
 614        /*
 615         * Compute all of the segment blocks
 616         *
 617         * The blocks before first segment and after last segment
 618         * are excluded.
 619         */
 620        blocks = nilfs->ns_blocks_per_segment * nilfs->ns_nsegments
 621                - nilfs->ns_first_data_block;
 622        nrsvblocks = nilfs->ns_nrsvsegs * nilfs->ns_blocks_per_segment;
 623
 624        /*
 625         * Compute the overhead
 626         *
 627         * When distributing meta data blocks outside segment structure,
 628         * We must count them as the overhead.
 629         */
 630        overhead = 0;
 631
 632        err = nilfs_count_free_blocks(nilfs, &nfreeblocks);
 633        if (unlikely(err))
 634                return err;
 635
 636        buf->f_type = NILFS_SUPER_MAGIC;
 637        buf->f_bsize = sb->s_blocksize;
 638        buf->f_blocks = blocks - overhead;
 639        buf->f_bfree = nfreeblocks;
 640        buf->f_bavail = (buf->f_bfree >= nrsvblocks) ?
 641                (buf->f_bfree - nrsvblocks) : 0;
 642        buf->f_files = atomic_read(&root->inodes_count);
 643        buf->f_ffree = 0; /* nilfs_count_free_inodes(sb); */
 644        buf->f_namelen = NILFS_NAME_LEN;
 645        buf->f_fsid.val[0] = (u32)id;
 646        buf->f_fsid.val[1] = (u32)(id >> 32);
 647
 648        return 0;
 649}
 650
 651static int nilfs_show_options(struct seq_file *seq, struct dentry *dentry)
 652{
 653        struct super_block *sb = dentry->d_sb;
 654        struct the_nilfs *nilfs = sb->s_fs_info;
 655        struct nilfs_root *root = NILFS_I(dentry->d_inode)->i_root;
 656
 657        if (!nilfs_test_opt(nilfs, BARRIER))
 658                seq_puts(seq, ",nobarrier");
 659        if (root->cno != NILFS_CPTREE_CURRENT_CNO)
 660                seq_printf(seq, ",cp=%llu", (unsigned long long)root->cno);
 661        if (nilfs_test_opt(nilfs, ERRORS_PANIC))
 662                seq_puts(seq, ",errors=panic");
 663        if (nilfs_test_opt(nilfs, ERRORS_CONT))
 664                seq_puts(seq, ",errors=continue");
 665        if (nilfs_test_opt(nilfs, STRICT_ORDER))
 666                seq_puts(seq, ",order=strict");
 667        if (nilfs_test_opt(nilfs, NORECOVERY))
 668                seq_puts(seq, ",norecovery");
 669        if (nilfs_test_opt(nilfs, DISCARD))
 670                seq_puts(seq, ",discard");
 671
 672        return 0;
 673}
 674
 675static const struct super_operations nilfs_sops = {
 676        .alloc_inode    = nilfs_alloc_inode,
 677        .destroy_inode  = nilfs_destroy_inode,
 678        .dirty_inode    = nilfs_dirty_inode,
 679        .evict_inode    = nilfs_evict_inode,
 680        .put_super      = nilfs_put_super,
 681        .sync_fs        = nilfs_sync_fs,
 682        .freeze_fs      = nilfs_freeze,
 683        .unfreeze_fs    = nilfs_unfreeze,
 684        .statfs         = nilfs_statfs,
 685        .remount_fs     = nilfs_remount,
 686        .show_options = nilfs_show_options
 687};
 688
 689enum {
 690        Opt_err_cont, Opt_err_panic, Opt_err_ro,
 691        Opt_barrier, Opt_nobarrier, Opt_snapshot, Opt_order, Opt_norecovery,
 692        Opt_discard, Opt_nodiscard, Opt_err,
 693};
 694
 695static match_table_t tokens = {
 696        {Opt_err_cont, "errors=continue"},
 697        {Opt_err_panic, "errors=panic"},
 698        {Opt_err_ro, "errors=remount-ro"},
 699        {Opt_barrier, "barrier"},
 700        {Opt_nobarrier, "nobarrier"},
 701        {Opt_snapshot, "cp=%u"},
 702        {Opt_order, "order=%s"},
 703        {Opt_norecovery, "norecovery"},
 704        {Opt_discard, "discard"},
 705        {Opt_nodiscard, "nodiscard"},
 706        {Opt_err, NULL}
 707};
 708
 709static int parse_options(char *options, struct super_block *sb, int is_remount)
 710{
 711        struct the_nilfs *nilfs = sb->s_fs_info;
 712        char *p;
 713        substring_t args[MAX_OPT_ARGS];
 714
 715        if (!options)
 716                return 1;
 717
 718        while ((p = strsep(&options, ",")) != NULL) {
 719                int token;
 720                if (!*p)
 721                        continue;
 722
 723                token = match_token(p, tokens, args);
 724                switch (token) {
 725                case Opt_barrier:
 726                        nilfs_set_opt(nilfs, BARRIER);
 727                        break;
 728                case Opt_nobarrier:
 729                        nilfs_clear_opt(nilfs, BARRIER);
 730                        break;
 731                case Opt_order:
 732                        if (strcmp(args[0].from, "relaxed") == 0)
 733                                /* Ordered data semantics */
 734                                nilfs_clear_opt(nilfs, STRICT_ORDER);
 735                        else if (strcmp(args[0].from, "strict") == 0)
 736                                /* Strict in-order semantics */
 737                                nilfs_set_opt(nilfs, STRICT_ORDER);
 738                        else
 739                                return 0;
 740                        break;
 741                case Opt_err_panic:
 742                        nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_PANIC);
 743                        break;
 744                case Opt_err_ro:
 745                        nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_RO);
 746                        break;
 747                case Opt_err_cont:
 748                        nilfs_write_opt(nilfs, ERROR_MODE, ERRORS_CONT);
 749                        break;
 750                case Opt_snapshot:
 751                        if (is_remount) {
 752                                printk(KERN_ERR
 753                                       "NILFS: \"%s\" option is invalid "
 754                                       "for remount.\n", p);
 755                                return 0;
 756                        }
 757                        break;
 758                case Opt_norecovery:
 759                        nilfs_set_opt(nilfs, NORECOVERY);
 760                        break;
 761                case Opt_discard:
 762                        nilfs_set_opt(nilfs, DISCARD);
 763                        break;
 764                case Opt_nodiscard:
 765                        nilfs_clear_opt(nilfs, DISCARD);
 766                        break;
 767                default:
 768                        printk(KERN_ERR
 769                               "NILFS: Unrecognized mount option \"%s\"\n", p);
 770                        return 0;
 771                }
 772        }
 773        return 1;
 774}
 775
 776static inline void
 777nilfs_set_default_options(struct super_block *sb,
 778                          struct nilfs_super_block *sbp)
 779{
 780        struct the_nilfs *nilfs = sb->s_fs_info;
 781
 782        nilfs->ns_mount_opt =
 783                NILFS_MOUNT_ERRORS_RO | NILFS_MOUNT_BARRIER;
 784}
 785
 786static int nilfs_setup_super(struct super_block *sb, int is_mount)
 787{
 788        struct the_nilfs *nilfs = sb->s_fs_info;
 789        struct nilfs_super_block **sbp;
 790        int max_mnt_count;
 791        int mnt_count;
 792
 793        /* nilfs->ns_sem must be locked by the caller. */
 794        sbp = nilfs_prepare_super(sb, 0);
 795        if (!sbp)
 796                return -EIO;
 797
 798        if (!is_mount)
 799                goto skip_mount_setup;
 800
 801        max_mnt_count = le16_to_cpu(sbp[0]->s_max_mnt_count);
 802        mnt_count = le16_to_cpu(sbp[0]->s_mnt_count);
 803
 804        if (nilfs->ns_mount_state & NILFS_ERROR_FS) {
 805                printk(KERN_WARNING
 806                       "NILFS warning: mounting fs with errors\n");
 807#if 0
 808        } else if (max_mnt_count >= 0 && mnt_count >= max_mnt_count) {
 809                printk(KERN_WARNING
 810                       "NILFS warning: maximal mount count reached\n");
 811#endif
 812        }
 813        if (!max_mnt_count)
 814                sbp[0]->s_max_mnt_count = cpu_to_le16(NILFS_DFL_MAX_MNT_COUNT);
 815
 816        sbp[0]->s_mnt_count = cpu_to_le16(mnt_count + 1);
 817        sbp[0]->s_mtime = cpu_to_le64(get_seconds());
 818
 819skip_mount_setup:
 820        sbp[0]->s_state =
 821                cpu_to_le16(le16_to_cpu(sbp[0]->s_state) & ~NILFS_VALID_FS);
 822        /* synchronize sbp[1] with sbp[0] */
 823        if (sbp[1])
 824                memcpy(sbp[1], sbp[0], nilfs->ns_sbsize);
 825        return nilfs_commit_super(sb, NILFS_SB_COMMIT_ALL);
 826}
 827
 828struct nilfs_super_block *nilfs_read_super_block(struct super_block *sb,
 829                                                 u64 pos, int blocksize,
 830                                                 struct buffer_head **pbh)
 831{
 832        unsigned long long sb_index = pos;
 833        unsigned long offset;
 834
 835        offset = do_div(sb_index, blocksize);
 836        *pbh = sb_bread(sb, sb_index);
 837        if (!*pbh)
 838                return NULL;
 839        return (struct nilfs_super_block *)((char *)(*pbh)->b_data + offset);
 840}
 841
 842int nilfs_store_magic_and_option(struct super_block *sb,
 843                                 struct nilfs_super_block *sbp,
 844                                 char *data)
 845{
 846        struct the_nilfs *nilfs = sb->s_fs_info;
 847
 848        sb->s_magic = le16_to_cpu(sbp->s_magic);
 849
 850        /* FS independent flags */
 851#ifdef NILFS_ATIME_DISABLE
 852        sb->s_flags |= MS_NOATIME;
 853#endif
 854
 855        nilfs_set_default_options(sb, sbp);
 856
 857        nilfs->ns_resuid = le16_to_cpu(sbp->s_def_resuid);
 858        nilfs->ns_resgid = le16_to_cpu(sbp->s_def_resgid);
 859        nilfs->ns_interval = le32_to_cpu(sbp->s_c_interval);
 860        nilfs->ns_watermark = le32_to_cpu(sbp->s_c_block_max);
 861
 862        return !parse_options(data, sb, 0) ? -EINVAL : 0 ;
 863}
 864
 865int nilfs_check_feature_compatibility(struct super_block *sb,
 866                                      struct nilfs_super_block *sbp)
 867{
 868        __u64 features;
 869
 870        features = le64_to_cpu(sbp->s_feature_incompat) &
 871                ~NILFS_FEATURE_INCOMPAT_SUPP;
 872        if (features) {
 873                printk(KERN_ERR "NILFS: couldn't mount because of unsupported "
 874                       "optional features (%llx)\n",
 875                       (unsigned long long)features);
 876                return -EINVAL;
 877        }
 878        features = le64_to_cpu(sbp->s_feature_compat_ro) &
 879                ~NILFS_FEATURE_COMPAT_RO_SUPP;
 880        if (!(sb->s_flags & MS_RDONLY) && features) {
 881                printk(KERN_ERR "NILFS: couldn't mount RDWR because of "
 882                       "unsupported optional features (%llx)\n",
 883                       (unsigned long long)features);
 884                return -EINVAL;
 885        }
 886        return 0;
 887}
 888
 889static int nilfs_get_root_dentry(struct super_block *sb,
 890                                 struct nilfs_root *root,
 891                                 struct dentry **root_dentry)
 892{
 893        struct inode *inode;
 894        struct dentry *dentry;
 895        int ret = 0;
 896
 897        inode = nilfs_iget(sb, root, NILFS_ROOT_INO);
 898        if (IS_ERR(inode)) {
 899                printk(KERN_ERR "NILFS: get root inode failed\n");
 900                ret = PTR_ERR(inode);
 901                goto out;
 902        }
 903        if (!S_ISDIR(inode->i_mode) || !inode->i_blocks || !inode->i_size) {
 904                iput(inode);
 905                printk(KERN_ERR "NILFS: corrupt root inode.\n");
 906                ret = -EINVAL;
 907                goto out;
 908        }
 909
 910        if (root->cno == NILFS_CPTREE_CURRENT_CNO) {
 911                dentry = d_find_alias(inode);
 912                if (!dentry) {
 913                        dentry = d_make_root(inode);
 914                        if (!dentry) {
 915                                ret = -ENOMEM;
 916                                goto failed_dentry;
 917                        }
 918                } else {
 919                        iput(inode);
 920                }
 921        } else {
 922                dentry = d_obtain_alias(inode);
 923                if (IS_ERR(dentry)) {
 924                        ret = PTR_ERR(dentry);
 925                        goto failed_dentry;
 926                }
 927        }
 928        *root_dentry = dentry;
 929 out:
 930        return ret;
 931
 932 failed_dentry:
 933        printk(KERN_ERR "NILFS: get root dentry failed\n");
 934        goto out;
 935}
 936
 937static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
 938                                 struct dentry **root_dentry)
 939{
 940        struct the_nilfs *nilfs = s->s_fs_info;
 941        struct nilfs_root *root;
 942        int ret;
 943
 944        mutex_lock(&nilfs->ns_snapshot_mount_mutex);
 945
 946        down_read(&nilfs->ns_segctor_sem);
 947        ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
 948        up_read(&nilfs->ns_segctor_sem);
 949        if (ret < 0) {
 950                ret = (ret == -ENOENT) ? -EINVAL : ret;
 951                goto out;
 952        } else if (!ret) {
 953                printk(KERN_ERR "NILFS: The specified checkpoint is "
 954                       "not a snapshot (checkpoint number=%llu).\n",
 955                       (unsigned long long)cno);
 956                ret = -EINVAL;
 957                goto out;
 958        }
 959
 960        ret = nilfs_attach_checkpoint(s, cno, false, &root);
 961        if (ret) {
 962                printk(KERN_ERR "NILFS: error loading snapshot "
 963                       "(checkpoint number=%llu).\n",
 964               (unsigned long long)cno);
 965                goto out;
 966        }
 967        ret = nilfs_get_root_dentry(s, root, root_dentry);
 968        nilfs_put_root(root);
 969 out:
 970        mutex_unlock(&nilfs->ns_snapshot_mount_mutex);
 971        return ret;
 972}
 973
 974static int nilfs_tree_was_touched(struct dentry *root_dentry)
 975{
 976        return root_dentry->d_count > 1;
 977}
 978
 979/**
 980 * nilfs_try_to_shrink_tree() - try to shrink dentries of a checkpoint
 981 * @root_dentry: root dentry of the tree to be shrunk
 982 *
 983 * This function returns true if the tree was in-use.
 984 */
 985static int nilfs_try_to_shrink_tree(struct dentry *root_dentry)
 986{
 987        if (have_submounts(root_dentry))
 988                return true;
 989        shrink_dcache_parent(root_dentry);
 990        return nilfs_tree_was_touched(root_dentry);
 991}
 992
 993int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno)
 994{
 995        struct the_nilfs *nilfs = sb->s_fs_info;
 996        struct nilfs_root *root;
 997        struct inode *inode;
 998        struct dentry *dentry;
 999        int ret;
1000
1001        if (cno < 0 || cno > nilfs->ns_cno)
1002                return false;
1003
1004        if (cno >= nilfs_last_cno(nilfs))
1005                return true;    /* protect recent checkpoints */
1006
1007        ret = false;
1008        root = nilfs_lookup_root(nilfs, cno);
1009        if (root) {
1010                inode = nilfs_ilookup(sb, root, NILFS_ROOT_INO);
1011                if (inode) {
1012                        dentry = d_find_alias(inode);
1013                        if (dentry) {
1014                                if (nilfs_tree_was_touched(dentry))
1015                                        ret = nilfs_try_to_shrink_tree(dentry);
1016                                dput(dentry);
1017                        }
1018                        iput(inode);
1019                }
1020                nilfs_put_root(root);
1021        }
1022        return ret;
1023}
1024
1025/**
1026 * nilfs_fill_super() - initialize a super block instance
1027 * @sb: super_block
1028 * @data: mount options
1029 * @silent: silent mode flag
1030 *
1031 * This function is called exclusively by nilfs->ns_mount_mutex.
1032 * So, the recovery process is protected from other simultaneous mounts.
1033 */
1034static int
1035nilfs_fill_super(struct super_block *sb, void *data, int silent)
1036{
1037        struct the_nilfs *nilfs;
1038        struct nilfs_root *fsroot;
1039        struct backing_dev_info *bdi;
1040        __u64 cno;
1041        int err;
1042
1043        nilfs = alloc_nilfs(sb->s_bdev);
1044        if (!nilfs)
1045                return -ENOMEM;
1046
1047        sb->s_fs_info = nilfs;
1048
1049        err = init_nilfs(nilfs, sb, (char *)data);
1050        if (err)
1051                goto failed_nilfs;
1052
1053        sb->s_op = &nilfs_sops;
1054        sb->s_export_op = &nilfs_export_ops;
1055        sb->s_root = NULL;
1056        sb->s_time_gran = 1;
1057        sb->s_max_links = NILFS_LINK_MAX;
1058
1059        bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
1060        sb->s_bdi = bdi ? : &default_backing_dev_info;
1061
1062        err = load_nilfs(nilfs, sb);
1063        if (err)
1064                goto failed_nilfs;
1065
1066        cno = nilfs_last_cno(nilfs);
1067        err = nilfs_attach_checkpoint(sb, cno, true, &fsroot);
1068        if (err) {
1069                printk(KERN_ERR "NILFS: error loading last checkpoint "
1070                       "(checkpoint number=%llu).\n", (unsigned long long)cno);
1071                goto failed_unload;
1072        }
1073
1074        if (!(sb->s_flags & MS_RDONLY)) {
1075                err = nilfs_attach_log_writer(sb, fsroot);
1076                if (err)
1077                        goto failed_checkpoint;
1078        }
1079
1080        err = nilfs_get_root_dentry(sb, fsroot, &sb->s_root);
1081        if (err)
1082                goto failed_segctor;
1083
1084        nilfs_put_root(fsroot);
1085
1086        if (!(sb->s_flags & MS_RDONLY)) {
1087                down_write(&nilfs->ns_sem);
1088                nilfs_setup_super(sb, true);
1089                up_write(&nilfs->ns_sem);
1090        }
1091
1092        return 0;
1093
1094 failed_segctor:
1095        nilfs_detach_log_writer(sb);
1096
1097 failed_checkpoint:
1098        nilfs_put_root(fsroot);
1099
1100 failed_unload:
1101        iput(nilfs->ns_sufile);
1102        iput(nilfs->ns_cpfile);
1103        iput(nilfs->ns_dat);
1104
1105 failed_nilfs:
1106        destroy_nilfs(nilfs);
1107        return err;
1108}
1109
1110static int nilfs_remount(struct super_block *sb, int *flags, char *data)
1111{
1112        struct the_nilfs *nilfs = sb->s_fs_info;
1113        unsigned long old_sb_flags;
1114        unsigned long old_mount_opt;
1115        int err;
1116
1117        old_sb_flags = sb->s_flags;
1118        old_mount_opt = nilfs->ns_mount_opt;
1119
1120        if (!parse_options(data, sb, 1)) {
1121                err = -EINVAL;
1122                goto restore_opts;
1123        }
1124        sb->s_flags = (sb->s_flags & ~MS_POSIXACL);
1125
1126        err = -EINVAL;
1127
1128        if (!nilfs_valid_fs(nilfs)) {
1129                printk(KERN_WARNING "NILFS (device %s): couldn't "
1130                       "remount because the filesystem is in an "
1131                       "incomplete recovery state.\n", sb->s_id);
1132                goto restore_opts;
1133        }
1134
1135        if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1136                goto out;
1137        if (*flags & MS_RDONLY) {
1138                /* Shutting down log writer */
1139                nilfs_detach_log_writer(sb);
1140                sb->s_flags |= MS_RDONLY;
1141
1142                /*
1143                 * Remounting a valid RW partition RDONLY, so set
1144                 * the RDONLY flag and then mark the partition as valid again.
1145                 */
1146                down_write(&nilfs->ns_sem);
1147                nilfs_cleanup_super(sb);
1148                up_write(&nilfs->ns_sem);
1149        } else {
1150                __u64 features;
1151                struct nilfs_root *root;
1152
1153                /*
1154                 * Mounting a RDONLY partition read-write, so reread and
1155                 * store the current valid flag.  (It may have been changed
1156                 * by fsck since we originally mounted the partition.)
1157                 */
1158                down_read(&nilfs->ns_sem);
1159                features = le64_to_cpu(nilfs->ns_sbp[0]->s_feature_compat_ro) &
1160                        ~NILFS_FEATURE_COMPAT_RO_SUPP;
1161                up_read(&nilfs->ns_sem);
1162                if (features) {
1163                        printk(KERN_WARNING "NILFS (device %s): couldn't "
1164                               "remount RDWR because of unsupported optional "
1165                               "features (%llx)\n",
1166                               sb->s_id, (unsigned long long)features);
1167                        err = -EROFS;
1168                        goto restore_opts;
1169                }
1170
1171                sb->s_flags &= ~MS_RDONLY;
1172
1173                root = NILFS_I(sb->s_root->d_inode)->i_root;
1174                err = nilfs_attach_log_writer(sb, root);
1175                if (err)
1176                        goto restore_opts;
1177
1178                down_write(&nilfs->ns_sem);
1179                nilfs_setup_super(sb, true);
1180                up_write(&nilfs->ns_sem);
1181        }
1182 out:
1183        return 0;
1184
1185 restore_opts:
1186        sb->s_flags = old_sb_flags;
1187        nilfs->ns_mount_opt = old_mount_opt;
1188        return err;
1189}
1190
1191struct nilfs_super_data {
1192        struct block_device *bdev;
1193        __u64 cno;
1194        int flags;
1195};
1196
1197/**
1198 * nilfs_identify - pre-read mount options needed to identify mount instance
1199 * @data: mount options
1200 * @sd: nilfs_super_data
1201 */
1202static int nilfs_identify(char *data, struct nilfs_super_data *sd)
1203{
1204        char *p, *options = data;
1205        substring_t args[MAX_OPT_ARGS];
1206        int token;
1207        int ret = 0;
1208
1209        do {
1210                p = strsep(&options, ",");
1211                if (p != NULL && *p) {
1212                        token = match_token(p, tokens, args);
1213                        if (token == Opt_snapshot) {
1214                                if (!(sd->flags & MS_RDONLY)) {
1215                                        ret++;
1216                                } else {
1217                                        sd->cno = simple_strtoull(args[0].from,
1218                                                                  NULL, 0);
1219                                        /*
1220                                         * No need to see the end pointer;
1221                                         * match_token() has done syntax
1222                                         * checking.
1223                                         */
1224                                        if (sd->cno == 0)
1225                                                ret++;
1226                                }
1227                        }
1228                        if (ret)
1229                                printk(KERN_ERR
1230                                       "NILFS: invalid mount option: %s\n", p);
1231                }
1232                if (!options)
1233                        break;
1234                BUG_ON(options == data);
1235                *(options - 1) = ',';
1236        } while (!ret);
1237        return ret;
1238}
1239
1240static int nilfs_set_bdev_super(struct super_block *s, void *data)
1241{
1242        s->s_bdev = data;
1243        s->s_dev = s->s_bdev->bd_dev;
1244        return 0;
1245}
1246
1247static int nilfs_test_bdev_super(struct super_block *s, void *data)
1248{
1249        return (void *)s->s_bdev == data;
1250}
1251
1252static struct dentry *
1253nilfs_mount(struct file_system_type *fs_type, int flags,
1254             const char *dev_name, void *data)
1255{
1256        struct nilfs_super_data sd;
1257        struct super_block *s;
1258        fmode_t mode = FMODE_READ | FMODE_EXCL;
1259        struct dentry *root_dentry;
1260        int err, s_new = false;
1261
1262        if (!(flags & MS_RDONLY))
1263                mode |= FMODE_WRITE;
1264
1265        sd.bdev = blkdev_get_by_path(dev_name, mode, fs_type);
1266        if (IS_ERR(sd.bdev))
1267                return ERR_CAST(sd.bdev);
1268
1269        sd.cno = 0;
1270        sd.flags = flags;
1271        if (nilfs_identify((char *)data, &sd)) {
1272                err = -EINVAL;
1273                goto failed;
1274        }
1275
1276        /*
1277         * once the super is inserted into the list by sget, s_umount
1278         * will protect the lockfs code from trying to start a snapshot
1279         * while we are mounting
1280         */
1281        mutex_lock(&sd.bdev->bd_fsfreeze_mutex);
1282        if (sd.bdev->bd_fsfreeze_count > 0) {
1283                mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1284                err = -EBUSY;
1285                goto failed;
1286        }
1287        s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, flags,
1288                 sd.bdev);
1289        mutex_unlock(&sd.bdev->bd_fsfreeze_mutex);
1290        if (IS_ERR(s)) {
1291                err = PTR_ERR(s);
1292                goto failed;
1293        }
1294
1295        if (!s->s_root) {
1296                char b[BDEVNAME_SIZE];
1297
1298                s_new = true;
1299
1300                /* New superblock instance created */
1301                s->s_mode = mode;
1302                strlcpy(s->s_id, bdevname(sd.bdev, b), sizeof(s->s_id));
1303                sb_set_blocksize(s, block_size(sd.bdev));
1304
1305                err = nilfs_fill_super(s, data, flags & MS_SILENT ? 1 : 0);
1306                if (err)
1307                        goto failed_super;
1308
1309                s->s_flags |= MS_ACTIVE;
1310        } else if (!sd.cno) {
1311                int busy = false;
1312
1313                if (nilfs_tree_was_touched(s->s_root)) {
1314                        busy = nilfs_try_to_shrink_tree(s->s_root);
1315                        if (busy && (flags ^ s->s_flags) & MS_RDONLY) {
1316                                printk(KERN_ERR "NILFS: the device already "
1317                                       "has a %s mount.\n",
1318                                       (s->s_flags & MS_RDONLY) ?
1319                                       "read-only" : "read/write");
1320                                err = -EBUSY;
1321                                goto failed_super;
1322                        }
1323                }
1324                if (!busy) {
1325                        /*
1326                         * Try remount to setup mount states if the current
1327                         * tree is not mounted and only snapshots use this sb.
1328                         */
1329                        err = nilfs_remount(s, &flags, data);
1330                        if (err)
1331                                goto failed_super;
1332                }
1333        }
1334
1335        if (sd.cno) {
1336                err = nilfs_attach_snapshot(s, sd.cno, &root_dentry);
1337                if (err)
1338                        goto failed_super;
1339        } else {
1340                root_dentry = dget(s->s_root);
1341        }
1342
1343        if (!s_new)
1344                blkdev_put(sd.bdev, mode);
1345
1346        return root_dentry;
1347
1348 failed_super:
1349        deactivate_locked_super(s);
1350
1351 failed:
1352        if (!s_new)
1353                blkdev_put(sd.bdev, mode);
1354        return ERR_PTR(err);
1355}
1356
1357struct file_system_type nilfs_fs_type = {
1358        .owner    = THIS_MODULE,
1359        .name     = "nilfs2",
1360        .mount    = nilfs_mount,
1361        .kill_sb  = kill_block_super,
1362        .fs_flags = FS_REQUIRES_DEV,
1363};
1364
1365static void nilfs_inode_init_once(void *obj)
1366{
1367        struct nilfs_inode_info *ii = obj;
1368
1369        INIT_LIST_HEAD(&ii->i_dirty);
1370#ifdef CONFIG_NILFS_XATTR
1371        init_rwsem(&ii->xattr_sem);
1372#endif
1373        address_space_init_once(&ii->i_btnode_cache);
1374        ii->i_bmap = &ii->i_bmap_data;
1375        inode_init_once(&ii->vfs_inode);
1376}
1377
1378static void nilfs_segbuf_init_once(void *obj)
1379{
1380        memset(obj, 0, sizeof(struct nilfs_segment_buffer));
1381}
1382
1383static void nilfs_destroy_cachep(void)
1384{
1385        /*
1386         * Make sure all delayed rcu free inodes are flushed before we
1387         * destroy cache.
1388         */
1389        rcu_barrier();
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
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.