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super.c

/*
 *  linux/fs/ext3/super.c
 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card (card@masi.ibp.fr)
 * Laboratoire MASI - Institut Blaise Pascal
 * Universite Pierre et Marie Curie (Paris VI)
 *
 *  from
 *
 *  linux/fs/minix/inode.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  Big-endian to little-endian byte-swapping/bitmaps by
 *        David S. Miller (davem@caip.rutgers.edu), 1995
 */

#include <linux/module.h>
#include <linux/string.h>
#include <linux/fs.h>
#include <linux/time.h>
#include <linux/jbd.h>
#include <linux/ext3_fs.h>
#include <linux/ext3_jbd.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/parser.h>
#include <linux/smp_lock.h>
#include <linux/buffer_head.h>
#include <linux/vfs.h>
#include <linux/random.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/quotaops.h>
#include <linux/seq_file.h>

#include <asm/uaccess.h>

#include "xattr.h"
#include "acl.h"
#include "namei.h"

static int ext3_load_journal(struct super_block *, struct ext3_super_block *,
                       unsigned long journal_devnum);
static int ext3_create_journal(struct super_block *, struct ext3_super_block *,
                         int);
static void ext3_commit_super (struct super_block * sb,
                         struct ext3_super_block * es,
                         int sync);
static void ext3_mark_recovery_complete(struct super_block * sb,
                              struct ext3_super_block * es);
static void ext3_clear_journal_err(struct super_block * sb,
                           struct ext3_super_block * es);
static int ext3_sync_fs(struct super_block *sb, int wait);
static const char *ext3_decode_error(struct super_block * sb, int errno,
                             char nbuf[16]);
static int ext3_remount (struct super_block * sb, int * flags, char * data);
static int ext3_statfs (struct dentry * dentry, struct kstatfs * buf);
static void ext3_unlockfs(struct super_block *sb);
static void ext3_write_super (struct super_block * sb);
static void ext3_write_super_lockfs(struct super_block *sb);

/* 
 * Wrappers for journal_start/end.
 *
 * The only special thing we need to do here is to make sure that all
 * journal_end calls result in the superblock being marked dirty, so
 * that sync() will call the filesystem's write_super callback if
 * appropriate. 
 */
handle_t *ext3_journal_start_sb(struct super_block *sb, int nblocks)
{
      journal_t *journal;

      if (sb->s_flags & MS_RDONLY)
            return ERR_PTR(-EROFS);

      /* Special case here: if the journal has aborted behind our
       * backs (eg. EIO in the commit thread), then we still need to
       * take the FS itself readonly cleanly. */
      journal = EXT3_SB(sb)->s_journal;
      if (is_journal_aborted(journal)) {
            ext3_abort(sb, __FUNCTION__,
                     "Detected aborted journal");
            return ERR_PTR(-EROFS);
      }

      return journal_start(journal, nblocks);
}

/* 
 * The only special thing we need to do here is to make sure that all
 * journal_stop calls result in the superblock being marked dirty, so
 * that sync() will call the filesystem's write_super callback if
 * appropriate. 
 */
int __ext3_journal_stop(const char *where, handle_t *handle)
{
      struct super_block *sb;
      int err;
      int rc;

      sb = handle->h_transaction->t_journal->j_private;
      err = handle->h_err;
      rc = journal_stop(handle);

      if (!err)
            err = rc;
      if (err)
            __ext3_std_error(sb, where, err);
      return err;
}

void ext3_journal_abort_handle(const char *caller, const char *err_fn,
            struct buffer_head *bh, handle_t *handle, int err)
{
      char nbuf[16];
      const char *errstr = ext3_decode_error(NULL, err, nbuf);

      if (bh)
            BUFFER_TRACE(bh, "abort");

      if (!handle->h_err)
            handle->h_err = err;

      if (is_handle_aborted(handle))
            return;

      printk(KERN_ERR "%s: aborting transaction: %s in %s\n",
             caller, errstr, err_fn);

      journal_abort_handle(handle);
}

/* Deal with the reporting of failure conditions on a filesystem such as
 * inconsistencies detected or read IO failures.
 *
 * On ext2, we can store the error state of the filesystem in the
 * superblock.  That is not possible on ext3, because we may have other
 * write ordering constraints on the superblock which prevent us from
 * writing it out straight away; and given that the journal is about to
 * be aborted, we can't rely on the current, or future, transactions to
 * write out the superblock safely.
 *
 * We'll just use the journal_abort() error code to record an error in
 * the journal instead.  On recovery, the journal will compain about
 * that error until we've noted it down and cleared it.
 */

static void ext3_handle_error(struct super_block *sb)
{
      struct ext3_super_block *es = EXT3_SB(sb)->s_es;

      EXT3_SB(sb)->s_mount_state |= EXT3_ERROR_FS;
      es->s_state |= cpu_to_le16(EXT3_ERROR_FS);

      if (sb->s_flags & MS_RDONLY)
            return;

      if (test_opt (sb, ERRORS_RO)) {
            printk (KERN_CRIT "Remounting filesystem read-only\n");
            sb->s_flags |= MS_RDONLY;
      } else {
            journal_t *journal = EXT3_SB(sb)->s_journal;

            EXT3_SB(sb)->s_mount_opt |= EXT3_MOUNT_ABORT;
            if (journal)
                  journal_abort(journal, -EIO);
      }
      if (test_opt(sb, ERRORS_PANIC))
            panic("EXT3-fs (device %s): panic forced after error\n",
                  sb->s_id);
      ext3_commit_super(sb, es, 1);
}

void ext3_error (struct super_block * sb, const char * function,
             const char * fmt, ...)
{
      va_list args;

      va_start(args, fmt);
      printk(KERN_CRIT "EXT3-fs error (device %s): %s: ",sb->s_id, function);
      vprintk(fmt, args);
      printk("\n");
      va_end(args);

      ext3_handle_error(sb);
}

static const char *ext3_decode_error(struct super_block * sb, int errno,
                             char nbuf[16])
{
      char *errstr = NULL;

      switch (errno) {
      case -EIO:
            errstr = "IO failure";
            break;
      case -ENOMEM:
            errstr = "Out of memory";
            break;
      case -EROFS:
            if (!sb || EXT3_SB(sb)->s_journal->j_flags & JFS_ABORT)
                  errstr = "Journal has aborted";
            else
                  errstr = "Readonly filesystem";
            break;
      default:
            /* If the caller passed in an extra buffer for unknown
             * errors, textualise them now.  Else we just return
             * NULL. */
            if (nbuf) {
                  /* Check for truncated error codes... */
                  if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
                        errstr = nbuf;
            }
            break;
      }

      return errstr;
}

/* __ext3_std_error decodes expected errors from journaling functions
 * automatically and invokes the appropriate error response.  */

void __ext3_std_error (struct super_block * sb, const char * function,
                   int errno)
{
      char nbuf[16];
      const char *errstr;

      /* Special case: if the error is EROFS, and we're not already
       * inside a transaction, then there's really no point in logging
       * an error. */
      if (errno == -EROFS && journal_current_handle() == NULL &&
          (sb->s_flags & MS_RDONLY))
            return;

      errstr = ext3_decode_error(sb, errno, nbuf);
      printk (KERN_CRIT "EXT3-fs error (device %s) in %s: %s\n",
            sb->s_id, function, errstr);

      ext3_handle_error(sb);
}

/*
 * ext3_abort is a much stronger failure handler than ext3_error.  The
 * abort function may be used to deal with unrecoverable failures such
 * as journal IO errors or ENOMEM at a critical moment in log management.
 *
 * We unconditionally force the filesystem into an ABORT|READONLY state,
 * unless the error response on the fs has been set to panic in which
 * case we take the easy way out and panic immediately.
 */

void ext3_abort (struct super_block * sb, const char * function,
             const char * fmt, ...)
{
      va_list args;

      printk (KERN_CRIT "ext3_abort called.\n");

      va_start(args, fmt);
      printk(KERN_CRIT "EXT3-fs error (device %s): %s: ",sb->s_id, function);
      vprintk(fmt, args);
      printk("\n");
      va_end(args);

      if (test_opt(sb, ERRORS_PANIC))
            panic("EXT3-fs panic from previous error\n");

      if (sb->s_flags & MS_RDONLY)
            return;

      printk(KERN_CRIT "Remounting filesystem read-only\n");
      EXT3_SB(sb)->s_mount_state |= EXT3_ERROR_FS;
      sb->s_flags |= MS_RDONLY;
      EXT3_SB(sb)->s_mount_opt |= EXT3_MOUNT_ABORT;
      journal_abort(EXT3_SB(sb)->s_journal, -EIO);
}

void ext3_warning (struct super_block * sb, const char * function,
               const char * fmt, ...)
{
      va_list args;

      va_start(args, fmt);
      printk(KERN_WARNING "EXT3-fs warning (device %s): %s: ",
             sb->s_id, function);
      vprintk(fmt, args);
      printk("\n");
      va_end(args);
}

void ext3_update_dynamic_rev(struct super_block *sb)
{
      struct ext3_super_block *es = EXT3_SB(sb)->s_es;

      if (le32_to_cpu(es->s_rev_level) > EXT3_GOOD_OLD_REV)
            return;

      ext3_warning(sb, __FUNCTION__,
                 "updating to rev %d because of new feature flag, "
                 "running e2fsck is recommended",
                 EXT3_DYNAMIC_REV);

      es->s_first_ino = cpu_to_le32(EXT3_GOOD_OLD_FIRST_INO);
      es->s_inode_size = cpu_to_le16(EXT3_GOOD_OLD_INODE_SIZE);
      es->s_rev_level = cpu_to_le32(EXT3_DYNAMIC_REV);
      /* leave es->s_feature_*compat flags alone */
      /* es->s_uuid will be set by e2fsck if empty */

      /*
       * The rest of the superblock fields should be zero, and if not it
       * means they are likely already in use, so leave them alone.  We
       * can leave it up to e2fsck to clean up any inconsistencies there.
       */
}

/*
 * Open the external journal device
 */
static struct block_device *ext3_blkdev_get(dev_t dev)
{
      struct block_device *bdev;
      char b[BDEVNAME_SIZE];

      bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE);
      if (IS_ERR(bdev))
            goto fail;
      return bdev;

fail:
      printk(KERN_ERR "EXT3: failed to open journal device %s: %ld\n",
                  __bdevname(dev, b), PTR_ERR(bdev));
      return NULL;
}

/*
 * Release the journal device
 */
static int ext3_blkdev_put(struct block_device *bdev)
{
      bd_release(bdev);
      return blkdev_put(bdev);
}

static int ext3_blkdev_remove(struct ext3_sb_info *sbi)
{
      struct block_device *bdev;
      int ret = -ENODEV;

      bdev = sbi->journal_bdev;
      if (bdev) {
            ret = ext3_blkdev_put(bdev);
            sbi->journal_bdev = NULL;
      }
      return ret;
}

static inline struct inode *orphan_list_entry(struct list_head *l)
{
      return &list_entry(l, struct ext3_inode_info, i_orphan)->vfs_inode;
}

static void dump_orphan_list(struct super_block *sb, struct ext3_sb_info *sbi)
{
      struct list_head *l;

      printk(KERN_ERR "sb orphan head is %d\n", 
             le32_to_cpu(sbi->s_es->s_last_orphan));

      printk(KERN_ERR "sb_info orphan list:\n");
      list_for_each(l, &sbi->s_orphan) {
            struct inode *inode = orphan_list_entry(l);
            printk(KERN_ERR "  "
                   "inode %s:%ld at %p: mode %o, nlink %d, next %d\n",
                   inode->i_sb->s_id, inode->i_ino, inode,
                   inode->i_mode, inode->i_nlink, 
                   NEXT_ORPHAN(inode));
      }
}

static void ext3_put_super (struct super_block * sb)
{
      struct ext3_sb_info *sbi = EXT3_SB(sb);
      struct ext3_super_block *es = sbi->s_es;
      int i;

      ext3_xattr_put_super(sb);
      journal_destroy(sbi->s_journal);
      if (!(sb->s_flags & MS_RDONLY)) {
            EXT3_CLEAR_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER);
            es->s_state = cpu_to_le16(sbi->s_mount_state);
            BUFFER_TRACE(sbi->s_sbh, "marking dirty");
            mark_buffer_dirty(sbi->s_sbh);
            ext3_commit_super(sb, es, 1);
      }

      for (i = 0; i < sbi->s_gdb_count; i++)
            brelse(sbi->s_group_desc[i]);
      kfree(sbi->s_group_desc);
      percpu_counter_destroy(&sbi->s_freeblocks_counter);
      percpu_counter_destroy(&sbi->s_freeinodes_counter);
      percpu_counter_destroy(&sbi->s_dirs_counter);
      brelse(sbi->s_sbh);
#ifdef CONFIG_QUOTA
      for (i = 0; i < MAXQUOTAS; i++)
            kfree(sbi->s_qf_names[i]);
#endif

      /* Debugging code just in case the in-memory inode orphan list
       * isn't empty.  The on-disk one can be non-empty if we've
       * detected an error and taken the fs readonly, but the
       * in-memory list had better be clean by this point. */
      if (!list_empty(&sbi->s_orphan))
            dump_orphan_list(sb, sbi);
      J_ASSERT(list_empty(&sbi->s_orphan));

      invalidate_bdev(sb->s_bdev, 0);
      if (sbi->journal_bdev && sbi->journal_bdev != sb->s_bdev) {
            /*
             * Invalidate the journal device's buffers.  We don't want them
             * floating about in memory - the physical journal device may
             * hotswapped, and it breaks the `ro-after' testing code.
             */
            sync_blockdev(sbi->journal_bdev);
            invalidate_bdev(sbi->journal_bdev, 0);
            ext3_blkdev_remove(sbi);
      }
      sb->s_fs_info = NULL;
      kfree(sbi);
      return;
}

static kmem_cache_t *ext3_inode_cachep;

/*
 * Called inside transaction, so use GFP_NOFS
 */
static struct inode *ext3_alloc_inode(struct super_block *sb)
{
      struct ext3_inode_info *ei;

      ei = kmem_cache_alloc(ext3_inode_cachep, SLAB_NOFS);
      if (!ei)
            return NULL;
#ifdef CONFIG_EXT3_FS_POSIX_ACL
      ei->i_acl = EXT3_ACL_NOT_CACHED;
      ei->i_default_acl = EXT3_ACL_NOT_CACHED;
#endif
      ei->i_block_alloc_info = NULL;
      ei->vfs_inode.i_version = 1;
      return &ei->vfs_inode;
}

static void ext3_destroy_inode(struct inode *inode)
{
      kmem_cache_free(ext3_inode_cachep, EXT3_I(inode));
}

static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
{
      struct ext3_inode_info *ei = (struct ext3_inode_info *) foo;

      if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
          SLAB_CTOR_CONSTRUCTOR) {
            INIT_LIST_HEAD(&ei->i_orphan);
#ifdef CONFIG_EXT3_FS_XATTR
            init_rwsem(&ei->xattr_sem);
#endif
            mutex_init(&ei->truncate_mutex);
            inode_init_once(&ei->vfs_inode);
      }
}
 
static int init_inodecache(void)
{
      ext3_inode_cachep = kmem_cache_create("ext3_inode_cache",
                                   sizeof(struct ext3_inode_info),
                                   0, (SLAB_RECLAIM_ACCOUNT|
                                    SLAB_MEM_SPREAD),
                                   init_once, NULL);
      if (ext3_inode_cachep == NULL)
            return -ENOMEM;
      return 0;
}

static void destroy_inodecache(void)
{
      if (kmem_cache_destroy(ext3_inode_cachep))
            printk(KERN_INFO "ext3_inode_cache: not all structures were freed\n");
}

static void ext3_clear_inode(struct inode *inode)
{
      struct ext3_block_alloc_info *rsv = EXT3_I(inode)->i_block_alloc_info;
#ifdef CONFIG_EXT3_FS_POSIX_ACL
      if (EXT3_I(inode)->i_acl &&
                  EXT3_I(inode)->i_acl != EXT3_ACL_NOT_CACHED) {
            posix_acl_release(EXT3_I(inode)->i_acl);
            EXT3_I(inode)->i_acl = EXT3_ACL_NOT_CACHED;
      }
      if (EXT3_I(inode)->i_default_acl &&
                  EXT3_I(inode)->i_default_acl != EXT3_ACL_NOT_CACHED) {
            posix_acl_release(EXT3_I(inode)->i_default_acl);
            EXT3_I(inode)->i_default_acl = EXT3_ACL_NOT_CACHED;
      }
#endif
      ext3_discard_reservation(inode);
      EXT3_I(inode)->i_block_alloc_info = NULL;
      if (unlikely(rsv))
            kfree(rsv);
}

static inline void ext3_show_quota_options(struct seq_file *seq, struct super_block *sb)
{
#if defined(CONFIG_QUOTA)
      struct ext3_sb_info *sbi = EXT3_SB(sb);

      if (sbi->s_jquota_fmt)
            seq_printf(seq, ",jqfmt=%s",
            (sbi->s_jquota_fmt == QFMT_VFS_OLD) ? "vfsold": "vfsv0");

      if (sbi->s_qf_names[USRQUOTA])
            seq_printf(seq, ",usrjquota=%s", sbi->s_qf_names[USRQUOTA]);

      if (sbi->s_qf_names[GRPQUOTA])
            seq_printf(seq, ",grpjquota=%s", sbi->s_qf_names[GRPQUOTA]);

      if (sbi->s_mount_opt & EXT3_MOUNT_USRQUOTA)
            seq_puts(seq, ",usrquota");

      if (sbi->s_mount_opt & EXT3_MOUNT_GRPQUOTA)
            seq_puts(seq, ",grpquota");
#endif
}

static int ext3_show_options(struct seq_file *seq, struct vfsmount *vfs)
{
      struct super_block *sb = vfs->mnt_sb;

      if (test_opt(sb, DATA_FLAGS) == EXT3_MOUNT_JOURNAL_DATA)
            seq_puts(seq, ",data=journal");
      else if (test_opt(sb, DATA_FLAGS) == EXT3_MOUNT_ORDERED_DATA)
            seq_puts(seq, ",data=ordered");
      else if (test_opt(sb, DATA_FLAGS) == EXT3_MOUNT_WRITEBACK_DATA)
            seq_puts(seq, ",data=writeback");

      ext3_show_quota_options(seq, sb);

      return 0;
}


static struct dentry *ext3_get_dentry(struct super_block *sb, void *vobjp)
{
      __u32 *objp = vobjp;
      unsigned long ino = objp[0];
      __u32 generation = objp[1];
      struct inode *inode;
      struct dentry *result;

      if (ino < EXT3_FIRST_INO(sb) && ino != EXT3_ROOT_INO)
            return ERR_PTR(-ESTALE);
      if (ino > le32_to_cpu(EXT3_SB(sb)->s_es->s_inodes_count))
            return ERR_PTR(-ESTALE);

      /* iget isn't really right if the inode is currently unallocated!!
       *
       * ext3_read_inode will return a bad_inode if the inode had been
       * deleted, so we should be safe.
       *
       * Currently we don't know the generation for parent directory, so
       * a generation of 0 means "accept any"
       */
      inode = iget(sb, ino);
      if (inode == NULL)
            return ERR_PTR(-ENOMEM);
      if (is_bad_inode(inode) ||
          (generation && inode->i_generation != generation)) {
            iput(inode);
            return ERR_PTR(-ESTALE);
      }
      /* now to find a dentry.
       * If possible, get a well-connected one
       */
      result = d_alloc_anon(inode);
      if (!result) {
            iput(inode);
            return ERR_PTR(-ENOMEM);
      }
      return result;
}

#ifdef CONFIG_QUOTA
#define QTYPE2NAME(t) ((t)==USRQUOTA?"user":"group")
#define QTYPE2MOPT(on, t) ((t)==USRQUOTA?((on)##USRJQUOTA):((on)##GRPJQUOTA))

static int ext3_dquot_initialize(struct inode *inode, int type);
static int ext3_dquot_drop(struct inode *inode);
static int ext3_write_dquot(struct dquot *dquot);
static int ext3_acquire_dquot(struct dquot *dquot);
static int ext3_release_dquot(struct dquot *dquot);
static int ext3_mark_dquot_dirty(struct dquot *dquot);
static int ext3_write_info(struct super_block *sb, int type);
static int ext3_quota_on(struct super_block *sb, int type, int format_id, char *path);
static int ext3_quota_on_mount(struct super_block *sb, int type);
static ssize_t ext3_quota_read(struct super_block *sb, int type, char *data,
                         size_t len, loff_t off);
static ssize_t ext3_quota_write(struct super_block *sb, int type,
                        const char *data, size_t len, loff_t off);

static struct dquot_operations ext3_quota_operations = {
      .initialize = ext3_dquot_initialize,
      .drop       = ext3_dquot_drop,
      .alloc_space      = dquot_alloc_space,
      .alloc_inode      = dquot_alloc_inode,
      .free_space = dquot_free_space,
      .free_inode = dquot_free_inode,
      .transfer   = dquot_transfer,
      .write_dquot      = ext3_write_dquot,
      .acquire_dquot    = ext3_acquire_dquot,
      .release_dquot    = ext3_release_dquot,
      .mark_dirty = ext3_mark_dquot_dirty,
      .write_info = ext3_write_info
};

static struct quotactl_ops ext3_qctl_operations = {
      .quota_on   = ext3_quota_on,
      .quota_off  = vfs_quota_off,
      .quota_sync = vfs_quota_sync,
      .get_info   = vfs_get_dqinfo,
      .set_info   = vfs_set_dqinfo,
      .get_dqblk  = vfs_get_dqblk,
      .set_dqblk  = vfs_set_dqblk
};
#endif

static struct super_operations ext3_sops = {
      .alloc_inode      = ext3_alloc_inode,
      .destroy_inode    = ext3_destroy_inode,
      .read_inode = ext3_read_inode,
      .write_inode      = ext3_write_inode,
      .dirty_inode      = ext3_dirty_inode,
      .delete_inode     = ext3_delete_inode,
      .put_super  = ext3_put_super,
      .write_super      = ext3_write_super,
      .sync_fs    = ext3_sync_fs,
      .write_super_lockfs = ext3_write_super_lockfs,
      .unlockfs   = ext3_unlockfs,
      .statfs           = ext3_statfs,
      .remount_fs = ext3_remount,
      .clear_inode      = ext3_clear_inode,
      .show_options     = ext3_show_options,
#ifdef CONFIG_QUOTA
      .quota_read = ext3_quota_read,
      .quota_write      = ext3_quota_write,
#endif
};

static struct export_operations ext3_export_ops = {
      .get_parent = ext3_get_parent,
      .get_dentry = ext3_get_dentry,
};

enum {
      Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
      Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
      Opt_nouid32, Opt_nocheck, Opt_debug, Opt_oldalloc, Opt_orlov,
      Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
      Opt_reservation, Opt_noreservation, Opt_noload, Opt_nobh, Opt_bh,
      Opt_commit, Opt_journal_update, Opt_journal_inum, Opt_journal_dev,
      Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,
      Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
      Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_quota, Opt_noquota,
      Opt_ignore, Opt_barrier, Opt_err, Opt_resize, Opt_usrquota,
      Opt_grpquota
};

static match_table_t tokens = {
      {Opt_bsd_df, "bsddf"},
      {Opt_minix_df, "minixdf"},
      {Opt_grpid, "grpid"},
      {Opt_grpid, "bsdgroups"},
      {Opt_nogrpid, "nogrpid"},
      {Opt_nogrpid, "sysvgroups"},
      {Opt_resgid, "resgid=%u"},
      {Opt_resuid, "resuid=%u"},
      {Opt_sb, "sb=%u"},
      {Opt_err_cont, "errors=continue"},
      {Opt_err_panic, "errors=panic"},
      {Opt_err_ro, "errors=remount-ro"},
      {Opt_nouid32, "nouid32"},
      {Opt_nocheck, "nocheck"},
      {Opt_nocheck, "check=none"},
      {Opt_debug, "debug"},
      {Opt_oldalloc, "oldalloc"},
      {Opt_orlov, "orlov"},
      {Opt_user_xattr, "user_xattr"},
      {Opt_nouser_xattr, "nouser_xattr"},
      {Opt_acl, "acl"},
      {Opt_noacl, "noacl"},
      {Opt_reservation, "reservation"},
      {Opt_noreservation, "noreservation"},
      {Opt_noload, "noload"},
      {Opt_nobh, "nobh"},
      {Opt_bh, "bh"},
      {Opt_commit, "commit=%u"},
      {Opt_journal_update, "journal=update"},
      {Opt_journal_inum, "journal=%u"},
      {Opt_journal_dev, "journal_dev=%u"},
      {Opt_abort, "abort"},
      {Opt_data_journal, "data=journal"},
      {Opt_data_ordered, "data=ordered"},
      {Opt_data_writeback, "data=writeback"},
      {Opt_offusrjquota, "usrjquota="},
      {Opt_usrjquota, "usrjquota=%s"},
      {Opt_offgrpjquota, "grpjquota="},
      {Opt_grpjquota, "grpjquota=%s"},
      {Opt_jqfmt_vfsold, "jqfmt=vfsold"},
      {Opt_jqfmt_vfsv0, "jqfmt=vfsv0"},
      {Opt_grpquota, "grpquota"},
      {Opt_noquota, "noquota"},
      {Opt_quota, "quota"},
      {Opt_usrquota, "usrquota"},
      {Opt_barrier, "barrier=%u"},
      {Opt_err, NULL},
      {Opt_resize, "resize"},
};

static ext3_fsblk_t get_sb_block(void **data)
{
      ext3_fsblk_t      sb_block;
      char        *options = (char *) *data;

      if (!options || strncmp(options, "sb=", 3) != 0)
            return 1;   /* Default location */
      options += 3;
      /*todo: use simple_strtoll with >32bit ext3 */
      sb_block = simple_strtoul(options, &options, 0);
      if (*options && *options != ',') {
            printk("EXT3-fs: Invalid sb specification: %s\n",
                   (char *) *data);
            return 1;
      }
      if (*options == ',')
            options++;
      *data = (void *) options;
      return sb_block;
}

static int parse_options (char *options, struct super_block *sb,
                    unsigned long *inum, unsigned long *journal_devnum,
                    ext3_fsblk_t *n_blocks_count, int is_remount)
{
      struct ext3_sb_info *sbi = EXT3_SB(sb);
      char * p;
      substring_t args[MAX_OPT_ARGS];
      int data_opt = 0;
      int option;
#ifdef CONFIG_QUOTA
      int qtype;
      char *qname;
#endif

      if (!options)
            return 1;

      while ((p = strsep (&options, ",")) != NULL) {
            int token;
            if (!*p)
                  continue;

            token = match_token(p, tokens, args);
            switch (token) {
            case Opt_bsd_df:
                  clear_opt (sbi->s_mount_opt, MINIX_DF);
                  break;
            case Opt_minix_df:
                  set_opt (sbi->s_mount_opt, MINIX_DF);
                  break;
            case Opt_grpid:
                  set_opt (sbi->s_mount_opt, GRPID);
                  break;
            case Opt_nogrpid:
                  clear_opt (sbi->s_mount_opt, GRPID);
                  break;
            case Opt_resuid:
                  if (match_int(&args[0], &option))
                        return 0;
                  sbi->s_resuid = option;
                  break;
            case Opt_resgid:
                  if (match_int(&args[0], &option))
                        return 0;
                  sbi->s_resgid = option;
                  break;
            case Opt_sb:
                  /* handled by get_sb_block() instead of here */
                  /* *sb_block = match_int(&args[0]); */
                  break;
            case Opt_err_panic:
                  clear_opt (sbi->s_mount_opt, ERRORS_CONT);
                  clear_opt (sbi->s_mount_opt, ERRORS_RO);
                  set_opt (sbi->s_mount_opt, ERRORS_PANIC);
                  break;
            case Opt_err_ro:
                  clear_opt (sbi->s_mount_opt, ERRORS_CONT);
                  clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
                  set_opt (sbi->s_mount_opt, ERRORS_RO);
                  break;
            case Opt_err_cont:
                  clear_opt (sbi->s_mount_opt, ERRORS_RO);
                  clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
                  set_opt (sbi->s_mount_opt, ERRORS_CONT);
                  break;
            case Opt_nouid32:
                  set_opt (sbi->s_mount_opt, NO_UID32);
                  break;
            case Opt_nocheck:
                  clear_opt (sbi->s_mount_opt, CHECK);
                  break;
            case Opt_debug:
                  set_opt (sbi->s_mount_opt, DEBUG);
                  break;
            case Opt_oldalloc:
                  set_opt (sbi->s_mount_opt, OLDALLOC);
                  break;
            case Opt_orlov:
                  clear_opt (sbi->s_mount_opt, OLDALLOC);
                  break;
#ifdef CONFIG_EXT3_FS_XATTR
            case Opt_user_xattr:
                  set_opt (sbi->s_mount_opt, XATTR_USER);
                  break;
            case Opt_nouser_xattr:
                  clear_opt (sbi->s_mount_opt, XATTR_USER);
                  break;
#else
            case Opt_user_xattr:
            case Opt_nouser_xattr:
                  printk("EXT3 (no)user_xattr options not supported\n");
                  break;
#endif
#ifdef CONFIG_EXT3_FS_POSIX_ACL
            case Opt_acl:
                  set_opt(sbi->s_mount_opt, POSIX_ACL);
                  break;
            case Opt_noacl:
                  clear_opt(sbi->s_mount_opt, POSIX_ACL);
                  break;
#else
            case Opt_acl:
            case Opt_noacl:
                  printk("EXT3 (no)acl options not supported\n");
                  break;
#endif
            case Opt_reservation:
                  set_opt(sbi->s_mount_opt, RESERVATION);
                  break;
            case Opt_noreservation:
                  clear_opt(sbi->s_mount_opt, RESERVATION);
                  break;
            case Opt_journal_update:
                  /* @@@ FIXME */
                  /* Eventually we will want to be able to create
                     a journal file here.  For now, only allow the
                     user to specify an existing inode to be the
                     journal file. */
                  if (is_remount) {
                        printk(KERN_ERR "EXT3-fs: cannot specify "
                               "journal on remount\n");
                        return 0;
                  }
                  set_opt (sbi->s_mount_opt, UPDATE_JOURNAL);
                  break;
            case Opt_journal_inum:
                  if (is_remount) {
                        printk(KERN_ERR "EXT3-fs: cannot specify "
                               "journal on remount\n");
                        return 0;
                  }
                  if (match_int(&args[0], &option))
                        return 0;
                  *inum = option;
                  break;
            case Opt_journal_dev:
                  if (is_remount) {
                        printk(KERN_ERR "EXT3-fs: cannot specify "
                               "journal on remount\n");
                        return 0;
                  }
                  if (match_int(&args[0], &option))
                        return 0;
                  *journal_devnum = option;
                  break;
            case Opt_noload:
                  set_opt (sbi->s_mount_opt, NOLOAD);
                  break;
            case Opt_commit:
                  if (match_int(&args[0], &option))
                        return 0;
                  if (option < 0)
                        return 0;
                  if (option == 0)
                        option = JBD_DEFAULT_MAX_COMMIT_AGE;
                  sbi->s_commit_interval = HZ * option;
                  break;
            case Opt_data_journal:
                  data_opt = EXT3_MOUNT_JOURNAL_DATA;
                  goto datacheck;
            case Opt_data_ordered:
                  data_opt = EXT3_MOUNT_ORDERED_DATA;
                  goto datacheck;
            case Opt_data_writeback:
                  data_opt = EXT3_MOUNT_WRITEBACK_DATA;
            datacheck:
                  if (is_remount) {
                        if ((sbi->s_mount_opt & EXT3_MOUNT_DATA_FLAGS)
                                    != data_opt) {
                              printk(KERN_ERR
                                    "EXT3-fs: cannot change data "
                                    "mode on remount\n");
                              return 0;
                        }
                  } else {
                        sbi->s_mount_opt &= ~EXT3_MOUNT_DATA_FLAGS;
                        sbi->s_mount_opt |= data_opt;
                  }
                  break;
#ifdef CONFIG_QUOTA
            case Opt_usrjquota:
                  qtype = USRQUOTA;
                  goto set_qf_name;
            case Opt_grpjquota:
                  qtype = GRPQUOTA;
set_qf_name:
                  if (sb_any_quota_enabled(sb)) {
                        printk(KERN_ERR
                              "EXT3-fs: Cannot change journalled "
                              "quota options when quota turned on.\n");
                        return 0;
                  }
                  qname = match_strdup(&args[0]);
                  if (!qname) {
                        printk(KERN_ERR
                              "EXT3-fs: not enough memory for "
                              "storing quotafile name.\n");
                        return 0;
                  }
                  if (sbi->s_qf_names[qtype] &&
                      strcmp(sbi->s_qf_names[qtype], qname)) {
                        printk(KERN_ERR
                              "EXT3-fs: %s quota file already "
                              "specified.\n", QTYPE2NAME(qtype));
                        kfree(qname);
                        return 0;
                  }
                  sbi->s_qf_names[qtype] = qname;
                  if (strchr(sbi->s_qf_names[qtype], '/')) {
                        printk(KERN_ERR
                              "EXT3-fs: quotafile must be on "
                              "filesystem root.\n");
                        kfree(sbi->s_qf_names[qtype]);
                        sbi->s_qf_names[qtype] = NULL;
                        return 0;
                  }
                  set_opt(sbi->s_mount_opt, QUOTA);
                  break;
            case Opt_offusrjquota:
                  qtype = USRQUOTA;
                  goto clear_qf_name;
            case Opt_offgrpjquota:
                  qtype = GRPQUOTA;
clear_qf_name:
                  if (sb_any_quota_enabled(sb)) {
                        printk(KERN_ERR "EXT3-fs: Cannot change "
                              "journalled quota options when "
                              "quota turned on.\n");
                        return 0;
                  }
                  /*
                   * The space will be released later when all options
                   * are confirmed to be correct
                   */
                  sbi->s_qf_names[qtype] = NULL;
                  break;
            case Opt_jqfmt_vfsold:
                  sbi->s_jquota_fmt = QFMT_VFS_OLD;
                  break;
            case Opt_jqfmt_vfsv0:
                  sbi->s_jquota_fmt = QFMT_VFS_V0;
                  break;
            case Opt_quota:
            case Opt_usrquota:
                  set_opt(sbi->s_mount_opt, QUOTA);
                  set_opt(sbi->s_mount_opt, USRQUOTA);
                  break;
            case Opt_grpquota:
                  set_opt(sbi->s_mount_opt, QUOTA);
                  set_opt(sbi->s_mount_opt, GRPQUOTA);
                  break;
            case Opt_noquota:
                  if (sb_any_quota_enabled(sb)) {
                        printk(KERN_ERR "EXT3-fs: Cannot change quota "
                              "options when quota turned on.\n");
                        return 0;
                  }
                  clear_opt(sbi->s_mount_opt, QUOTA);
                  clear_opt(sbi->s_mount_opt, USRQUOTA);
                  clear_opt(sbi->s_mount_opt, GRPQUOTA);
                  break;
#else
            case Opt_quota:
            case Opt_usrquota:
            case Opt_grpquota:
            case Opt_usrjquota:
            case Opt_grpjquota:
            case Opt_offusrjquota:
            case Opt_offgrpjquota:
            case Opt_jqfmt_vfsold:
            case Opt_jqfmt_vfsv0:
                  printk(KERN_ERR
                        "EXT3-fs: journalled quota options not "
                        "supported.\n");
                  break;
            case Opt_noquota:
                  break;
#endif
            case Opt_abort:
                  set_opt(sbi->s_mount_opt, ABORT);
                  break;
            case Opt_barrier:
                  if (match_int(&args[0], &option))
                        return 0;
                  if (option)
                        set_opt(sbi->s_mount_opt, BARRIER);
                  else
                        clear_opt(sbi->s_mount_opt, BARRIER);
                  break;
            case Opt_ignore:
                  break;
            case Opt_resize:
                  if (!is_remount) {
                        printk("EXT3-fs: resize option only available "
                              "for remount\n");
                        return 0;
                  }
                  if (match_int(&args[0], &option) != 0)
                        return 0;
                  *n_blocks_count = option;
                  break;
            case Opt_nobh:
                  set_opt(sbi->s_mount_opt, NOBH);
                  break;
            case Opt_bh:
                  clear_opt(sbi->s_mount_opt, NOBH);
                  break;
            default:
                  printk (KERN_ERR
                        "EXT3-fs: Unrecognized mount option \"%s\" "
                        "or missing value\n", p);
                  return 0;
            }
      }
#ifdef CONFIG_QUOTA
      if (sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
            if ((sbi->s_mount_opt & EXT3_MOUNT_USRQUOTA) &&
                 sbi->s_qf_names[USRQUOTA])
                  clear_opt(sbi->s_mount_opt, USRQUOTA);

            if ((sbi->s_mount_opt & EXT3_MOUNT_GRPQUOTA) &&
                 sbi->s_qf_names[GRPQUOTA])
                  clear_opt(sbi->s_mount_opt, GRPQUOTA);

            if ((sbi->s_qf_names[USRQUOTA] &&
                        (sbi->s_mount_opt & EXT3_MOUNT_GRPQUOTA)) ||
                (sbi->s_qf_names[GRPQUOTA] &&
                        (sbi->s_mount_opt & EXT3_MOUNT_USRQUOTA))) {
                  printk(KERN_ERR "EXT3-fs: old and new quota "
                              "format mixing.\n");
                  return 0;
            }

            if (!sbi->s_jquota_fmt) {
                  printk(KERN_ERR "EXT3-fs: journalled quota format "
                              "not specified.\n");
                  return 0;
            }
      } else {
            if (sbi->s_jquota_fmt) {
                  printk(KERN_ERR "EXT3-fs: journalled quota format "
                              "specified with no journalling "
                              "enabled.\n");
                  return 0;
            }
      }
#endif
      return 1;
}

static int ext3_setup_super(struct super_block *sb, struct ext3_super_block *es,
                      int read_only)
{
      struct ext3_sb_info *sbi = EXT3_SB(sb);
      int res = 0;

      if (le32_to_cpu(es->s_rev_level) > EXT3_MAX_SUPP_REV) {
            printk (KERN_ERR "EXT3-fs warning: revision level too high, "
                  "forcing read-only mode\n");
            res = MS_RDONLY;
      }
      if (read_only)
            return res;
      if (!(sbi->s_mount_state & EXT3_VALID_FS))
            printk (KERN_WARNING "EXT3-fs warning: mounting unchecked fs, "
                  "running e2fsck is recommended\n");
      else if ((sbi->s_mount_state & EXT3_ERROR_FS))
            printk (KERN_WARNING
                  "EXT3-fs warning: mounting fs with errors, "
                  "running e2fsck is recommended\n");
      else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
             le16_to_cpu(es->s_mnt_count) >=
             (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
            printk (KERN_WARNING
                  "EXT3-fs warning: maximal mount count reached, "
                  "running e2fsck is recommended\n");
      else if (le32_to_cpu(es->s_checkinterval) &&
            (le32_to_cpu(es->s_lastcheck) +
                  le32_to_cpu(es->s_checkinterval) <= get_seconds()))
            printk (KERN_WARNING
                  "EXT3-fs warning: checktime reached, "
                  "running e2fsck is recommended\n");
#if 0
            /* @@@ We _will_ want to clear the valid bit if we find
                   inconsistencies, to force a fsck at reboot.  But for
                   a plain journaled filesystem we can keep it set as
                   valid forever! :) */
      es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) & ~EXT3_VALID_FS);
#endif
      if (!(__s16) le16_to_cpu(es->s_max_mnt_count))
            es->s_max_mnt_count = cpu_to_le16(EXT3_DFL_MAX_MNT_COUNT);
      es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
      es->s_mtime = cpu_to_le32(get_seconds());
      ext3_update_dynamic_rev(sb);
      EXT3_SET_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER);

      ext3_commit_super(sb, es, 1);
      if (test_opt(sb, DEBUG))
            printk(KERN_INFO "[EXT3 FS bs=%lu, gc=%lu, "
                        "bpg=%lu, ipg=%lu, mo=%04lx]\n",
                  sb->s_blocksize,
                  sbi->s_groups_count,
                  EXT3_BLOCKS_PER_GROUP(sb),
                  EXT3_INODES_PER_GROUP(sb),
                  sbi->s_mount_opt);

      printk(KERN_INFO "EXT3 FS on %s, ", sb->s_id);
      if (EXT3_SB(sb)->s_journal->j_inode == NULL) {
            char b[BDEVNAME_SIZE];

            printk("external journal on %s\n",
                  bdevname(EXT3_SB(sb)->s_journal->j_dev, b));
      } else {
            printk("internal journal\n");
      }
      return res;
}

/* Called at mount-time, super-block is locked */
static int ext3_check_descriptors (struct super_block * sb)
{
      struct ext3_sb_info *sbi = EXT3_SB(sb);
      ext3_fsblk_t block = le32_to_cpu(sbi->s_es->s_first_data_block);
      struct ext3_group_desc * gdp = NULL;
      int desc_block = 0;
      int i;

      ext3_debug ("Checking group descriptors");

      for (i = 0; i < sbi->s_groups_count; i++)
      {
            if ((i % EXT3_DESC_PER_BLOCK(sb)) == 0)
                  gdp = (struct ext3_group_desc *)
                              sbi->s_group_desc[desc_block++]->b_data;
            if (le32_to_cpu(gdp->bg_block_bitmap) < block ||
                le32_to_cpu(gdp->bg_block_bitmap) >=
                        block + EXT3_BLOCKS_PER_GROUP(sb))
            {
                  ext3_error (sb, "ext3_check_descriptors",
                            "Block bitmap for group %d"
                            " not in group (block %lu)!",
                            i, (unsigned long)
                              le32_to_cpu(gdp->bg_block_bitmap));
                  return 0;
            }
            if (le32_to_cpu(gdp->bg_inode_bitmap) < block ||
                le32_to_cpu(gdp->bg_inode_bitmap) >=
                        block + EXT3_BLOCKS_PER_GROUP(sb))
            {
                  ext3_error (sb, "ext3_check_descriptors",
                            "Inode bitmap for group %d"
                            " not in group (block %lu)!",
                            i, (unsigned long)
                              le32_to_cpu(gdp->bg_inode_bitmap));
                  return 0;
            }
            if (le32_to_cpu(gdp->bg_inode_table) < block ||
                le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >=
                block + EXT3_BLOCKS_PER_GROUP(sb))
            {
                  ext3_error (sb, "ext3_check_descriptors",
                            "Inode table for group %d"
                            " not in group (block %lu)!",
                            i, (unsigned long)
                              le32_to_cpu(gdp->bg_inode_table));
                  return 0;
            }
            block += EXT3_BLOCKS_PER_GROUP(sb);
            gdp++;
      }

      sbi->s_es->s_free_blocks_count=cpu_to_le32(ext3_count_free_blocks(sb));
      sbi->s_es->s_free_inodes_count=cpu_to_le32(ext3_count_free_inodes(sb));
      return 1;
}


/* ext3_orphan_cleanup() walks a singly-linked list of inodes (starting at
 * the superblock) which were deleted from all directories, but held open by
 * a process at the time of a crash.  We walk the list and try to delete these
 * inodes at recovery time (only with a read-write filesystem).
 *
 * In order to keep the orphan inode chain consistent during traversal (in
 * case of crash during recovery), we link each inode into the superblock
 * orphan list_head and handle it the same way as an inode deletion during
 * normal operation (which journals the operations for us).
 *
 * We only do an iget() and an iput() on each inode, which is very safe if we
 * accidentally point at an in-use or already deleted inode.  The worst that
 * can happen in this case is that we get a "bit already cleared" message from
 * ext3_free_inode().  The only reason we would point at a wrong inode is if
 * e2fsck was run on this filesystem, and it must have already done the orphan
 * inode cleanup for us, so we can safely abort without any further action.
 */
static void ext3_orphan_cleanup (struct super_block * sb,
                         struct ext3_super_block * es)
{
      unsigned int s_flags = sb->s_flags;
      int nr_orphans = 0, nr_truncates = 0;
#ifdef CONFIG_QUOTA
      int i;
#endif
      if (!es->s_last_orphan) {
            jbd_debug(4, "no orphan inodes to clean up\n");
            return;
      }

      if (EXT3_SB(sb)->s_mount_state & EXT3_ERROR_FS) {
            if (es->s_last_orphan)
                  jbd_debug(1, "Errors on filesystem, "
                          "clearing orphan list.\n");
            es->s_last_orphan = 0;
            jbd_debug(1, "Skipping orphan recovery on fs with errors.\n");
            return;
      }

      if (s_flags & MS_RDONLY) {
            printk(KERN_INFO "EXT3-fs: %s: orphan cleanup on readonly fs\n",
                   sb->s_id);
            sb->s_flags &= ~MS_RDONLY;
      }
#ifdef CONFIG_QUOTA
      /* Needed for iput() to work correctly and not trash data */
      sb->s_flags |= MS_ACTIVE;
      /* Turn on quotas so that they are updated correctly */
      for (i = 0; i < MAXQUOTAS; i++) {
            if (EXT3_SB(sb)->s_qf_names[i]) {
                  int ret = ext3_quota_on_mount(sb, i);
                  if (ret < 0)
                        printk(KERN_ERR
                              "EXT3-fs: Cannot turn on journalled "
                              "quota: error %d\n", ret);
            }
      }
#endif

      while (es->s_last_orphan) {
            struct inode *inode;

            if (!(inode =
                  ext3_orphan_get(sb, le32_to_cpu(es->s_last_orphan)))) {
                  es->s_last_orphan = 0;
                  break;
            }

            list_add(&EXT3_I(inode)->i_orphan, &EXT3_SB(sb)->s_orphan);
            DQUOT_INIT(inode);
            if (inode->i_nlink) {
                  printk(KERN_DEBUG
                        "%s: truncating inode %ld to %Ld bytes\n",
                        __FUNCTION__, inode->i_ino, inode->i_size);
                  jbd_debug(2, "truncating inode %ld to %Ld bytes\n",
                          inode->i_ino, inode->i_size);
                  ext3_truncate(inode);
                  nr_truncates++;
            } else {
                  printk(KERN_DEBUG
                        "%s: deleting unreferenced inode %ld\n",
                        __FUNCTION__, inode->i_ino);
                  jbd_debug(2, "deleting unreferenced inode %ld\n",
                          inode->i_ino);
                  nr_orphans++;
            }
            iput(inode);  /* The delete magic happens here! */
      }

#define PLURAL(x) (x), ((x)==1) ? "" : "s"

      if (nr_orphans)
            printk(KERN_INFO "EXT3-fs: %s: %d orphan inode%s deleted\n",
                   sb->s_id, PLURAL(nr_orphans));
      if (nr_truncates)
            printk(KERN_INFO "EXT3-fs: %s: %d truncate%s cleaned up\n",
                   sb->s_id, PLURAL(nr_truncates));
#ifdef CONFIG_QUOTA
      /* Turn quotas off */
      for (i = 0; i < MAXQUOTAS; i++) {
            if (sb_dqopt(sb)->files[i])
                  vfs_quota_off(sb, i);
      }
#endif
      sb->s_flags = s_flags; /* Restore MS_RDONLY status */
}

#define log2(n) ffz(~(n))

/*
 * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 * We need to be 1 filesystem block less than the 2^32 sector limit.
 */
static loff_t ext3_max_size(int bits)
{
      loff_t res = EXT3_NDIR_BLOCKS;
      /* This constant is calculated to be the largest file size for a
       * dense, 4k-blocksize file such that the total number of
       * sectors in the file, including data and all indirect blocks,
       * does not exceed 2^32. */
      const loff_t upper_limit = 0x1ff7fffd000LL;

      res += 1LL << (bits-2);
      res += 1LL << (2*(bits-2));
      res += 1LL << (3*(bits-2));
      res <<= bits;
      if (res > upper_limit)
            res = upper_limit;
      return res;
}

static ext3_fsblk_t descriptor_loc(struct super_block *sb,
                            ext3_fsblk_t logic_sb_block,
                            int nr)
{
      struct ext3_sb_info *sbi = EXT3_SB(sb);
      unsigned long bg, first_meta_bg;
      int has_super = 0;

      first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);

      if (!EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_META_BG) ||
          nr < first_meta_bg)
            return (logic_sb_block + nr + 1);
      bg = sbi->s_desc_per_block * nr;
      if (ext3_bg_has_super(sb, bg))
            has_super = 1;
      return (has_super + ext3_group_first_block_no(sb, bg));
}


static int ext3_fill_super (struct super_block *sb, void *data, int silent)
{
      struct buffer_head * bh;
      struct ext3_super_block *es = NULL;
      struct ext3_sb_info *sbi;
      ext3_fsblk_t block;
      ext3_fsblk_t sb_block = get_sb_block(&data);
      ext3_fsblk_t logic_sb_block;
      unsigned long offset = 0;
      unsigned long journal_inum = 0;
      unsigned long journal_devnum = 0;
      unsigned long def_mount_opts;
      struct inode *root;
      int blocksize;
      int hblock;
      int db_count;
      int i;
      int needs_recovery;
      __le32 features;

      sbi = kmalloc(sizeof(*sbi), GFP_KERNEL);
      if (!sbi)
            return -ENOMEM;
      sb->s_fs_info = sbi;
      memset(sbi, 0, sizeof(*sbi));
      sbi->s_mount_opt = 0;
      sbi->s_resuid = EXT3_DEF_RESUID;
      sbi->s_resgid = EXT3_DEF_RESGID;

      unlock_kernel();

      blocksize = sb_min_blocksize(sb, EXT3_MIN_BLOCK_SIZE);
      if (!blocksize) {
            printk(KERN_ERR "EXT3-fs: unable to set blocksize\n");
            goto out_fail;
      }

      /*
       * The ext3 superblock will not be buffer aligned for other than 1kB
       * block sizes.  We need to calculate the offset from buffer start.
       */
      if (blocksize != EXT3_MIN_BLOCK_SIZE) {
            logic_sb_block = (sb_block * EXT3_MIN_BLOCK_SIZE) / blocksize;
            offset = (sb_block * EXT3_MIN_BLOCK_SIZE) % blocksize;
      } else {
            logic_sb_block = sb_block;
      }

      if (!(bh = sb_bread(sb, logic_sb_block))) {
            printk (KERN_ERR "EXT3-fs: unable to read superblock\n");
            goto out_fail;
      }
      /*
       * Note: s_es must be initialized as soon as possible because
       *       some ext3 macro-instructions depend on its value
       */
      es = (struct ext3_super_block *) (((char *)bh->b_data) + offset);
      sbi->s_es = es;
      sb->s_magic = le16_to_cpu(es->s_magic);
      if (sb->s_magic != EXT3_SUPER_MAGIC)
            goto cantfind_ext3;

      /* Set defaults before we parse the mount options */
      def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
      if (def_mount_opts & EXT3_DEFM_DEBUG)
            set_opt(sbi->s_mount_opt, DEBUG);
      if (def_mount_opts & EXT3_DEFM_BSDGROUPS)
            set_opt(sbi->s_mount_opt, GRPID);
      if (def_mount_opts & EXT3_DEFM_UID16)
            set_opt(sbi->s_mount_opt, NO_UID32);
      if (def_mount_opts & EXT3_DEFM_XATTR_USER)
            set_opt(sbi->s_mount_opt, XATTR_USER);
      if (def_mount_opts & EXT3_DEFM_ACL)
            set_opt(sbi->s_mount_opt, POSIX_ACL);
      if ((def_mount_opts & EXT3_DEFM_JMODE) == EXT3_DEFM_JMODE_DATA)
            sbi->s_mount_opt |= EXT3_MOUNT_JOURNAL_DATA;
      else if ((def_mount_opts & EXT3_DEFM_JMODE) == EXT3_DEFM_JMODE_ORDERED)
            sbi->s_mount_opt |= EXT3_MOUNT_ORDERED_DATA;
      else if ((def_mount_opts & EXT3_DEFM_JMODE) == EXT3_DEFM_JMODE_WBACK)
            sbi->s_mount_opt |= EXT3_MOUNT_WRITEBACK_DATA;

      if (le16_to_cpu(sbi->s_es->s_errors) == EXT3_ERRORS_PANIC)
            set_opt(sbi->s_mount_opt, ERRORS_PANIC);
      else if (le16_to_cpu(sbi->s_es->s_errors) == EXT3_ERRORS_RO)
            set_opt(sbi->s_mount_opt, ERRORS_RO);

      sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
      sbi->s_resgid = le16_to_cpu(es->s_def_resgid);

      set_opt(sbi->s_mount_opt, RESERVATION);

      if (!parse_options ((char *) data, sb, &journal_inum, &journal_devnum,
                      NULL, 0))
            goto failed_mount;

      sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
            ((sbi->s_mount_opt & EXT3_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);

      if (le32_to_cpu(es->s_rev_level) == EXT3_GOOD_OLD_REV &&
          (EXT3_HAS_COMPAT_FEATURE(sb, ~0U) ||
           EXT3_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
           EXT3_HAS_INCOMPAT_FEATURE(sb, ~0U)))
            printk(KERN_WARNING 
                   "EXT3-fs warning: feature flags set on rev 0 fs, "
                   "running e2fsck is recommended\n");
      /*
       * Check feature flags regardless of the revision level, since we
       * previously didn't change the revision level when setting the flags,
       * so there is a chance incompat flags are set on a rev 0 filesystem.
       */
      features = EXT3_HAS_INCOMPAT_FEATURE(sb, ~EXT3_FEATURE_INCOMPAT_SUPP);
      if (features) {
            printk(KERN_ERR "EXT3-fs: %s: couldn't mount because of "
                   "unsupported optional features (%x).\n",
                   sb->s_id, le32_to_cpu(features));
            goto failed_mount;
      }
      features = EXT3_HAS_RO_COMPAT_FEATURE(sb, ~EXT3_FEATURE_RO_COMPAT_SUPP);
      if (!(sb->s_flags & MS_RDONLY) && features) {
            printk(KERN_ERR "EXT3-fs: %s: couldn't mount RDWR because of "
                   "unsupported optional features (%x).\n",
                   sb->s_id, le32_to_cpu(features));
            goto failed_mount;
      }
      blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);

      if (blocksize < EXT3_MIN_BLOCK_SIZE ||
          blocksize > EXT3_MAX_BLOCK_SIZE) {
            printk(KERN_ERR 
                   "EXT3-fs: Unsupported filesystem blocksize %d on %s.\n",
                   blocksize, sb->s_id);
            goto failed_mount;
      }

      hblock = bdev_hardsect_size(sb->s_bdev);
      if (sb->s_blocksize != blocksize) {
            /*
             * Make sure the blocksize for the filesystem is larger
             * than the hardware sectorsize for the machine.
             */
            if (blocksize < hblock) {
                  printk(KERN_ERR "EXT3-fs: blocksize %d too small for "
                         "device blocksize %d.\n", blocksize, hblock);
                  goto failed_mount;
            }

            brelse (bh);
            sb_set_blocksize(sb, blocksize);
            logic_sb_block = (sb_block * EXT3_MIN_BLOCK_SIZE) / blocksize;
            offset = (sb_block * EXT3_MIN_BLOCK_SIZE) % blocksize;
            bh = sb_bread(sb, logic_sb_block);
            if (!bh) {
                  printk(KERN_ERR 
                         "EXT3-fs: Can't read superblock on 2nd try.\n");
                  goto failed_mount;
            }
            es = (struct ext3_super_block *)(((char *)bh->b_data) + offset);
            sbi->s_es = es;
            if (es->s_magic != cpu_to_le16(EXT3_SUPER_MAGIC)) {
                  printk (KERN_ERR 
                        "EXT3-fs: Magic mismatch, very weird !\n");
                  goto failed_mount;
            }
      }

      sb->s_maxbytes = ext3_max_size(sb->s_blocksize_bits);

      if (le32_to_cpu(es->s_rev_level) == EXT3_GOOD_OLD_REV) {
            sbi->s_inode_size = EXT3_GOOD_OLD_INODE_SIZE;
            sbi->s_first_ino = EXT3_GOOD_OLD_FIRST_INO;
      } else {
            sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
            sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
            if ((sbi->s_inode_size < EXT3_GOOD_OLD_INODE_SIZE) ||
                (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
                (sbi->s_inode_size > blocksize)) {
                  printk (KERN_ERR
                        "EXT3-fs: unsupported inode size: %d\n",
                        sbi->s_inode_size);
                  goto failed_mount;
            }
      }
      sbi->s_frag_size = EXT3_MIN_FRAG_SIZE <<
                           le32_to_cpu(es->s_log_frag_size);
      if (blocksize != sbi->s_frag_size) {
            printk(KERN_ERR
                   "EXT3-fs: fragsize %lu != blocksize %u (unsupported)\n",
                   sbi->s_frag_size, blocksize);
            goto failed_mount;
      }
      sbi->s_frags_per_block = 1;
      sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
      sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
      sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
      if (EXT3_INODE_SIZE(sb) == 0)
            goto cantfind_ext3;
      sbi->s_inodes_per_block = blocksize / EXT3_INODE_SIZE(sb);
      if (sbi->s_inodes_per_block == 0)
            goto cantfind_ext3;
      sbi->s_itb_per_group = sbi->s_inodes_per_group /
                              sbi->s_inodes_per_block;
      sbi->s_desc_per_block = blocksize / sizeof(struct ext3_group_desc);
      sbi->s_sbh = bh;
      sbi->s_mount_state = le16_to_cpu(es->s_state);
      sbi->s_addr_per_block_bits = log2(EXT3_ADDR_PER_BLOCK(sb));
      sbi->s_desc_per_block_bits = log2(EXT3_DESC_PER_BLOCK(sb));
      for (i=0; i < 4; i++)
            sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]);
      sbi->s_def_hash_version = es->s_def_hash_version;

      if (sbi->s_blocks_per_group > blocksize * 8) {
            printk (KERN_ERR
                  "EXT3-fs: #blocks per group too big: %lu\n",
                  sbi->s_blocks_per_group);
            goto failed_mount;
      }
      if (sbi->s_frags_per_group > blocksize * 8) {
            printk (KERN_ERR
                  "EXT3-fs: #fragments per group too big: %lu\n",
                  sbi->s_frags_per_group);
            goto failed_mount;
      }
      if (sbi->s_inodes_per_group > blocksize * 8) {
            printk (KERN_ERR
                  "EXT3-fs: #inodes per group too big: %lu\n",
                  sbi->s_inodes_per_group);
            goto failed_mount;
      }

      if (le32_to_cpu(es->s_blocks_count) >
                (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
            printk(KERN_ERR "EXT3-fs: filesystem on %s:"
                  " too large to mount safely\n", sb->s_id);
            if (sizeof(sector_t) < 8)
                  printk(KERN_WARNING "EXT3-fs: CONFIG_LBD not "
                              "enabled\n");
            goto failed_mount;
      }

      if (EXT3_BLOCKS_PER_GROUP(sb) == 0)
            goto cantfind_ext3;
      sbi->s_groups_count = (le32_to_cpu(es->s_blocks_count) -
                         le32_to_cpu(es->s_first_data_block) +
                         EXT3_BLOCKS_PER_GROUP(sb) - 1) /
                        EXT3_BLOCKS_PER_GROUP(sb);
      db_count = (sbi->s_groups_count + EXT3_DESC_PER_BLOCK(sb) - 1) /
               EXT3_DESC_PER_BLOCK(sb);
      sbi->s_group_desc = kmalloc(db_count * sizeof (struct buffer_head *),
                            GFP_KERNEL);
      if (sbi->s_group_desc == NULL) {
            printk (KERN_ERR "EXT3-fs: not enough memory\n");
            goto failed_mount;
      }

      bgl_lock_init(&sbi->s_blockgroup_lock);

      for (i = 0; i < db_count; i++) {
            block = descriptor_loc(sb, logic_sb_block, i);
            sbi->s_group_desc[i] = sb_bread(sb, block);
            if (!sbi->s_group_desc[i]) {
                  printk (KERN_ERR "EXT3-fs: "
                        "can't read group descriptor %d\n", i);
                  db_count = i;
                  goto failed_mount2;
            }
      }
      if (!ext3_check_descriptors (sb)) {
            printk(KERN_ERR "EXT3-fs: group descriptors corrupted!\n");
            goto failed_mount2;
      }
      sbi->s_gdb_count = db_count;
      get_random_bytes(&sbi->s_next_generation, sizeof(u32));
      spin_lock_init(&sbi->s_next_gen_lock);

      percpu_counter_init(&sbi->s_freeblocks_counter,
            ext3_count_free_blocks(sb));
      percpu_counter_init(&sbi->s_freeinodes_counter,
            ext3_count_free_inodes(sb));
      percpu_counter_init(&sbi->s_dirs_counter,
            ext3_count_dirs(sb));

      /* per fileystem reservation list head & lock */
      spin_lock_init(&sbi->s_rsv_window_lock);
      sbi->s_rsv_window_root = RB_ROOT;
      /* Add a single, static dummy reservation to the start of the
       * reservation window list --- it gives us a placeholder for
       * append-at-start-of-list which makes the allocation logic
       * _much_ simpler. */
      sbi->s_rsv_window_head.rsv_start = EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
      sbi->s_rsv_window_head.rsv_end = EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
      sbi->s_rsv_window_head.rsv_alloc_hit = 0;
      sbi->s_rsv_window_head.rsv_goal_size = 0;
      ext3_rsv_window_add(sb, &sbi->s_rsv_window_head);

      /*
       * set up enough so that it can read an inode
       */
      sb->s_op = &ext3_sops;
      sb->s_export_op = &ext3_export_ops;
      sb->s_xattr = ext3_xattr_handlers;
#ifdef CONFIG_QUOTA
      sb->s_qcop = &ext3_qctl_operations;
      sb->dq_op = &ext3_quota_operations;
#endif
      INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */

      sb->s_root = NULL;

      needs_recovery = (es->s_last_orphan != 0 ||
                    EXT3_HAS_INCOMPAT_FEATURE(sb,
                            EXT3_FEATURE_INCOMPAT_RECOVER));

      /*
       * The first inode we look at is the journal inode.  Don't try
       * root first: it may be modified in the journal!
       */
      if (!test_opt(sb, NOLOAD) &&
          EXT3_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL)) {
            if (ext3_load_journal(sb, es, journal_devnum))
                  goto failed_mount3;
      } else if (journal_inum) {
            if (ext3_create_journal(sb, es, journal_inum))
                  goto failed_mount3;
      } else {
            if (!silent)
                  printk (KERN_ERR
                        "ext3: No journal on filesystem on %s\n",
                        sb->s_id);
            goto failed_mount3;
      }

      /* We have now updated the journal if required, so we can
       * validate the data journaling mode. */
      switch (test_opt(sb, DATA_FLAGS)) {
      case 0:
            /* No mode set, assume a default based on the journal
                   capabilities: ORDERED_DATA if the journal can
                   cope, else JOURNAL_DATA */
            if (journal_check_available_features
                (sbi->s_journal, 0, 0, JFS_FEATURE_INCOMPAT_REVOKE))
                  set_opt(sbi->s_mount_opt, ORDERED_DATA);
            else
                  set_opt(sbi->s_mount_opt, JOURNAL_DATA);
            break;

      case EXT3_MOUNT_ORDERED_DATA:
      case EXT3_MOUNT_WRITEBACK_DATA:
            if (!journal_check_available_features
                (sbi->s_journal, 0, 0, JFS_FEATURE_INCOMPAT_REVOKE)) {
                  printk(KERN_ERR "EXT3-fs: Journal does not support "
                         "requested data journaling mode\n");
                  goto failed_mount4;
            }
      default:
            break;
      }

      if (test_opt(sb, NOBH)) {
            if (!(test_opt(sb, DATA_FLAGS) == EXT3_MOUNT_WRITEBACK_DATA)) {
                  printk(KERN_WARNING "EXT3-fs: Ignoring nobh option - "
                        "its supported only with writeback mode\n");
                  clear_opt(sbi->s_mount_opt, NOBH);
            }
      }
      /*
       * The journal_load will have done any necessary log recovery,
       * so we can safely mount the rest of the filesystem now.
       */

      root = iget(sb, EXT3_ROOT_INO);
      sb->s_root = d_alloc_root(root);
      if (!sb->s_root) {
            printk(KERN_ERR "EXT3-fs: get root inode failed\n");
            iput(root);
            goto failed_mount4;
      }
      if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
            dput(sb->s_root);
            sb->s_root = NULL;
            printk(KERN_ERR "EXT3-fs: corrupt root inode, run e2fsck\n");
            goto failed_mount4;
      }

      ext3_setup_super (sb, es, sb->s_flags & MS_RDONLY);
      /*
       * akpm: core read_super() calls in here with the superblock locked.
       * That deadlocks, because orphan cleanup needs to lock the superblock
       * in numerous places.  Here we just pop the lock - it's relatively
       * harmless, because we are now ready to accept write_super() requests,
       * and aviro says that's the only reason for hanging onto the
       * superblock lock.
       */
      EXT3_SB(sb)->s_mount_state |= EXT3_ORPHAN_FS;
      ext3_orphan_cleanup(sb, es);
      EXT3_SB(sb)->s_mount_state &= ~EXT3_ORPHAN_FS;
      if (needs_recovery)
            printk (KERN_INFO "EXT3-fs: recovery complete.\n");
      ext3_mark_recovery_complete(sb, es);
      printk (KERN_INFO "EXT3-fs: mounted filesystem with %s data mode.\n",
            test_opt(sb,DATA_FLAGS) == EXT3_MOUNT_JOURNAL_DATA ? "journal":
            test_opt(sb,DATA_FLAGS) == EXT3_MOUNT_ORDERED_DATA ? "ordered":
            "writeback");

      lock_kernel();
      return 0;

cantfind_ext3:
      if (!silent)
            printk(KERN_ERR "VFS: Can't find ext3 filesystem on dev %s.\n",
                   sb->s_id);
      goto failed_mount;

failed_mount4:
      journal_destroy(sbi->s_journal);
failed_mount3:
      percpu_counter_destroy(&sbi->s_freeblocks_counter);
      percpu_counter_destroy(&sbi->s_freeinodes_counter);
      percpu_counter_destroy(&sbi->s_dirs_counter);
failed_mount2:
      for (i = 0; i < db_count; i++)
            brelse(sbi->s_group_desc[i]);
      kfree(sbi->s_group_desc);
failed_mount:
#ifdef CONFIG_QUOTA
      for (i = 0; i < MAXQUOTAS; i++)
            kfree(sbi->s_qf_names[i]);
#endif
      ext3_blkdev_remove(sbi);
      brelse(bh);
out_fail:
      sb->s_fs_info = NULL;
      kfree(sbi);
      lock_kernel();
      return -EINVAL;
}

/*
 * Setup any per-fs journal parameters now.  We'll do this both on
 * initial mount, once the journal has been initialised but before we've
 * done any recovery; and again on any subsequent remount. 
 */
static void ext3_init_journal_params(struct super_block *sb, journal_t *journal)
{
      struct ext3_sb_info *sbi = EXT3_SB(sb);

      if (sbi->s_commit_interval)
            journal->j_commit_interval = sbi->s_commit_interval;
      /* We could also set up an ext3-specific default for the commit
       * interval here, but for now we'll just fall back to the jbd
       * default. */

      spin_lock(&journal->j_state_lock);
      if (test_opt(sb, BARRIER))
            journal->j_flags |= JFS_BARRIER;
      else
            journal->j_flags &= ~JFS_BARRIER;
      spin_unlock(&journal->j_state_lock);
}

static journal_t *ext3_get_journal(struct super_block *sb, int journal_inum)
{
      struct inode *journal_inode;
      journal_t *journal;

      /* First, test for the existence of a valid inode on disk.  Bad
       * things happen if we iget() an unused inode, as the subsequent
       * iput() will try to delete it. */

      journal_inode = iget(sb, journal_inum);
      if (!journal_inode) {
            printk(KERN_ERR "EXT3-fs: no journal found.\n");
            return NULL;
      }
      if (!journal_inode->i_nlink) {
            make_bad_inode(journal_inode);
            iput(journal_inode);
            printk(KERN_ERR "EXT3-fs: journal inode is deleted.\n");
            return NULL;
      }

      jbd_debug(2, "Journal inode found at %p: %Ld bytes\n",
              journal_inode, journal_inode->i_size);
      if (is_bad_inode(journal_inode) || !S_ISREG(journal_inode->i_mode)) {
            printk(KERN_ERR "EXT3-fs: invalid journal inode.\n");
            iput(journal_inode);
            return NULL;
      }

      journal = journal_init_inode(journal_inode);
      if (!journal) {
            printk(KERN_ERR "EXT3-fs: Could not load journal inode\n");
            iput(journal_inode);
            return NULL;
      }
      journal->j_private = sb;
      ext3_init_journal_params(sb, journal);
      return journal;
}

static journal_t *ext3_get_dev_journal(struct super_block *sb,
                               dev_t j_dev)
{
      struct buffer_head * bh;
      journal_t *journal;
      ext3_fsblk_t start;
      ext3_fsblk_t len;
      int hblock, blocksize;
      ext3_fsblk_t sb_block;
      unsigned long offset;
      struct ext3_super_block * es;
      struct block_device *bdev;

      bdev = ext3_blkdev_get(j_dev);
      if (bdev == NULL)
            return NULL;

      if (bd_claim(bdev, sb)) {
            printk(KERN_ERR
                    "EXT3: failed to claim external journal device.\n");
            blkdev_put(bdev);
            return NULL;
      }

      blocksize = sb->s_blocksize;
      hblock = bdev_hardsect_size(bdev);
      if (blocksize < hblock) {
            printk(KERN_ERR
                  "EXT3-fs: blocksize too small for journal device.\n");
            goto out_bdev;
      }

      sb_block = EXT3_MIN_BLOCK_SIZE / blocksize;
      offset = EXT3_MIN_BLOCK_SIZE % blocksize;
      set_blocksize(bdev, blocksize);
      if (!(bh = __bread(bdev, sb_block, blocksize))) {
            printk(KERN_ERR "EXT3-fs: couldn't read superblock of "
                   "external journal\n");
            goto out_bdev;
      }

      es = (struct ext3_super_block *) (((char *)bh->b_data) + offset);
      if ((le16_to_cpu(es->s_magic) != EXT3_SUPER_MAGIC) ||
          !(le32_to_cpu(es->s_feature_incompat) &
            EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)) {
            printk(KERN_ERR "EXT3-fs: external journal has "
                              "bad superblock\n");
            brelse(bh);
            goto out_bdev;
      }

      if (memcmp(EXT3_SB(sb)->s_es->s_journal_uuid, es->s_uuid, 16)) {
            printk(KERN_ERR "EXT3-fs: journal UUID does not match\n");
            brelse(bh);
            goto out_bdev;
      }

      len = le32_to_cpu(es->s_blocks_count);
      start = sb_block + 1;
      brelse(bh); /* we're done with the superblock */

      journal = journal_init_dev(bdev, sb->s_bdev,
                              start, len, blocksize);
      if (!journal) {
            printk(KERN_ERR "EXT3-fs: failed to create device journal\n");
            goto out_bdev;
      }
      journal->j_private = sb;
      ll_rw_block(READ, 1, &journal->j_sb_buffer);
      wait_on_buffer(journal->j_sb_buffer);
      if (!buffer_uptodate(journal->j_sb_buffer)) {
            printk(KERN_ERR "EXT3-fs: I/O error on journal device\n");
            goto out_journal;
      }
      if (be32_to_cpu(journal->j_superblock->s_nr_users) != 1) {
            printk(KERN_ERR "EXT3-fs: External journal has more than one "
                              "user (unsupported) - %d\n",
                  be32_to_cpu(journal->j_superblock->s_nr_users));
            goto out_journal;
      }
      EXT3_SB(sb)->journal_bdev = bdev;
      ext3_init_journal_params(sb, journal);
      return journal;
out_journal:
      journal_destroy(journal);
out_bdev:
      ext3_blkdev_put(bdev);
      return NULL;
}

static int ext3_load_journal(struct super_block *sb,
                       struct ext3_super_block *es,
                       unsigned long journal_devnum)
{
      journal_t *journal;
      int journal_inum = le32_to_cpu(es->s_journal_inum);
      dev_t journal_dev;
      int err = 0;
      int really_read_only;

      if (journal_devnum &&
          journal_devnum != le32_to_cpu(es->s_journal_dev)) {
            printk(KERN_INFO "EXT3-fs: external journal device major/minor "
                  "numbers have changed\n");
            journal_dev = new_decode_dev(journal_devnum);
      } else
            journal_dev = new_decode_dev(le32_to_cpu(es->s_journal_dev));

      really_read_only = bdev_read_only(sb->s_bdev);

      /*
       * Are we loading a blank journal or performing recovery after a
       * crash?  For recovery, we need to check in advance whether we
       * can get read-write access to the device.
       */

      if (EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER)) {
            if (sb->s_flags & MS_RDONLY) {
                  printk(KERN_INFO "EXT3-fs: INFO: recovery "
                              "required on readonly filesystem.\n");
                  if (really_read_only) {
                        printk(KERN_ERR "EXT3-fs: write access "
                              "unavailable, cannot proceed.\n");
                        return -EROFS;
                  }
                  printk (KERN_INFO "EXT3-fs: write access will "
                              "be enabled during recovery.\n");
            }
      }

      if (journal_inum && journal_dev) {
            printk(KERN_ERR "EXT3-fs: filesystem has both journal "
                   "and inode journals!\n");
            return -EINVAL;
      }

      if (journal_inum) {
            if (!(journal = ext3_get_journal(sb, journal_inum)))
                  return -EINVAL;
      } else {
            if (!(journal = ext3_get_dev_journal(sb, journal_dev)))
                  return -EINVAL;
      }

      if (!really_read_only && test_opt(sb, UPDATE_JOURNAL)) {
            err = journal_update_format(journal);
            if (err)  {
                  printk(KERN_ERR "EXT3-fs: error updating journal.\n");
                  journal_destroy(journal);
                  return err;
            }
      }

      if (!EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER))
            err = journal_wipe(journal, !really_read_only);
      if (!err)
            err = journal_load(journal);

      if (err) {
            printk(KERN_ERR "EXT3-fs: error loading journal.\n");
            journal_destroy(journal);
            return err;
      }

      EXT3_SB(sb)->s_journal = journal;
      ext3_clear_journal_err(sb, es);

      if (journal_devnum &&
          journal_devnum != le32_to_cpu(es->s_journal_dev)) {
            es->s_journal_dev = cpu_to_le32(journal_devnum);
            sb->s_dirt = 1;

            /* Make sure we flush the recovery flag to disk. */
            ext3_commit_super(sb, es, 1);
      }

      return 0;
}

static int ext3_create_journal(struct super_block * sb,
                         struct ext3_super_block * es,
                         int journal_inum)
{
      journal_t *journal;

      if (sb->s_flags & MS_RDONLY) {
            printk(KERN_ERR "EXT3-fs: readonly filesystem when trying to "
                        "create journal.\n");
            return -EROFS;
      }

      if (!(journal = ext3_get_journal(sb, journal_inum)))
            return -EINVAL;

      printk(KERN_INFO "EXT3-fs: creating new journal on inode %d\n",
             journal_inum);

      if (journal_create(journal)) {
            printk(KERN_ERR "EXT3-fs: error creating journal.\n");
            journal_destroy(journal);
            return -EIO;
      }

      EXT3_SB(sb)->s_journal = journal;

      ext3_update_dynamic_rev(sb);
      EXT3_SET_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER);
      EXT3_SET_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL);

      es->s_journal_inum = cpu_to_le32(journal_inum);
      sb->s_dirt = 1;

      /* Make sure we flush the recovery flag to disk. */
      ext3_commit_super(sb, es, 1);

      return 0;
}

static void ext3_commit_super (struct super_block * sb,
                         struct ext3_super_block * es,
                         int sync)
{
      struct buffer_head *sbh = EXT3_SB(sb)->s_sbh;

      if (!sbh)
            return;
      es->s_wtime = cpu_to_le32(get_seconds());
      es->s_free_blocks_count = cpu_to_le32(ext3_count_free_blocks(sb));
      es->s_free_inodes_count = cpu_to_le32(ext3_count_free_inodes(sb));
      BUFFER_TRACE(sbh, "marking dirty");
      mark_buffer_dirty(sbh);
      if (sync)
            sync_dirty_buffer(sbh);
}


/*
 * Have we just finished recovery?  If so, and if we are mounting (or
 * remounting) the filesystem readonly, then we will end up with a
 * consistent fs on disk.  Record that fact.
 */
static void ext3_mark_recovery_complete(struct super_block * sb,
                              struct ext3_super_block * es)
{
      journal_t *journal = EXT3_SB(sb)->s_journal;

      journal_lock_updates(journal);
      journal_flush(journal);
      if (EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER) &&
          sb->s_flags & MS_RDONLY) {
            EXT3_CLEAR_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER);
            sb->s_dirt = 0;
            ext3_commit_super(sb, es, 1);
      }
      journal_unlock_updates(journal);
}

/*
 * If we are mounting (or read-write remounting) a filesystem whose journal
 * has recorded an error from a previous lifetime, move that error to the
 * main filesystem now.
 */
static void ext3_clear_journal_err(struct super_block * sb,
                           struct ext3_super_block * es)
{
      journal_t *journal;
      int j_errno;
      const char *errstr;

      journal = EXT3_SB(sb)->s_journal;

      /*
       * Now check for any error status which may have been recorded in the
       * journal by a prior ext3_error() or ext3_abort()
       */

      j_errno = journal_errno(journal);
      if (j_errno) {
            char nbuf[16];

            errstr = ext3_decode_error(sb, j_errno, nbuf);
            ext3_warning(sb, __FUNCTION__, "Filesystem error recorded "
                       "from previous mount: %s", errstr);
            ext3_warning(sb, __FUNCTION__, "Marking fs in need of "
                       "filesystem check.");

            EXT3_SB(sb)->s_mount_state |= EXT3_ERROR_FS;
            es->s_state |= cpu_to_le16(EXT3_ERROR_FS);
            ext3_commit_super (sb, es, 1);

            journal_clear_err(journal);
      }
}

/*
 * Force the running and committing transactions to commit,
 * and wait on the commit.
 */
int ext3_force_commit(struct super_block *sb)
{
      journal_t *journal;
      int ret;

      if (sb->s_flags & MS_RDONLY)
            return 0;

      journal = EXT3_SB(sb)->s_journal;
      sb->s_dirt = 0;
      ret = ext3_journal_force_commit(journal);
      return ret;
}

/*
 * Ext3 always journals updates to the superblock itself, so we don't
 * have to propagate any other updates to the superblock on disk at this
 * point.  Just start an async writeback to get the buffers on their way
 * to the disk.
 *
 * This implicitly triggers the writebehind on sync().
 */

static void ext3_write_super (struct super_block * sb)
{
      if (mutex_trylock(&sb->s_lock) != 0)
            BUG();
      sb->s_dirt = 0;
}

static int ext3_sync_fs(struct super_block *sb, int wait)
{
      tid_t target;

      sb->s_dirt = 0;
      if (journal_start_commit(EXT3_SB(sb)->s_journal, &target)) {
            if (wait)
                  log_wait_commit(EXT3_SB(sb)->s_journal, target);
      }
      return 0;
}

/*
 * LVM calls this function before a (read-only) snapshot is created.  This
 * gives us a chance to flush the journal completely and mark the fs clean.
 */
static void ext3_write_super_lockfs(struct super_block *sb)
{
      sb->s_dirt = 0;

      if (!(sb->s_flags & MS_RDONLY)) {
            journal_t *journal = EXT3_SB(sb)->s_journal;

            /* Now we set up the journal barrier. */
            journal_lock_updates(journal);
            journal_flush(journal);

            /* Journal blocked and flushed, clear needs_recovery flag. */
            EXT3_CLEAR_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER);
            ext3_commit_super(sb, EXT3_SB(sb)->s_es, 1);
      }
}

/*
 * Called by LVM after the snapshot is done.  We need to reset the RECOVER
 * flag here, even though the filesystem is not technically dirty yet.
 */
static void ext3_unlockfs(struct super_block *sb)
{
      if (!(sb->s_flags & MS_RDONLY)) {
            lock_super(sb);
            /* Reser the needs_recovery flag before the fs is unlocked. */
            EXT3_SET_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER);
            ext3_commit_super(sb, EXT3_SB(sb)->s_es, 1);
            unlock_super(sb);
            journal_unlock_updates(EXT3_SB(sb)->s_journal);
      }
}

static int ext3_remount (struct super_block * sb, int * flags, char * data)
{
      struct ext3_super_block * es;
      struct ext3_sb_info *sbi = EXT3_SB(sb);
      ext3_fsblk_t n_blocks_count = 0;
      unsigned long old_sb_flags;
      struct ext3_mount_options old_opts;
      int err;
#ifdef CONFIG_QUOTA
      int i;
#endif

      /* Store the original options */
      old_sb_flags = sb->s_flags;
      old_opts.s_mount_opt = sbi->s_mount_opt;
      old_opts.s_resuid = sbi->s_resuid;
      old_opts.s_resgid = sbi->s_resgid;
      old_opts.s_commit_interval = sbi->s_commit_interval;
#ifdef CONFIG_QUOTA
      old_opts.s_jquota_fmt = sbi->s_jquota_fmt;
      for (i = 0; i < MAXQUOTAS; i++)
            old_opts.s_qf_names[i] = sbi->s_qf_names[i];
#endif

      /*
       * Allow the "check" option to be passed as a remount option.
       */
      if (!parse_options(data, sb, NULL, NULL, &n_blocks_count, 1)) {
            err = -EINVAL;
            goto restore_opts;
      }

      if (sbi->s_mount_opt & EXT3_MOUNT_ABORT)
            ext3_abort(sb, __FUNCTION__, "Abort forced by user");

      sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
            ((sbi->s_mount_opt & EXT3_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);

      es = sbi->s_es;

      ext3_init_journal_params(sb, sbi->s_journal);

      if ((*flags & MS_RDONLY) != (sb->s_flags & MS_RDONLY) ||
            n_blocks_count > le32_to_cpu(es->s_blocks_count)) {
            if (sbi->s_mount_opt & EXT3_MOUNT_ABORT) {
                  err = -EROFS;
                  goto restore_opts;
            }

            if (*flags & MS_RDONLY) {
                  /*
                   * First of all, the unconditional stuff we have to do
                   * to disable replay of the journal when we next remount
                   */
                  sb->s_flags |= MS_RDONLY;

                  /*
                   * OK, test if we are remounting a valid rw partition
                   * readonly, and if so set the rdonly flag and then
                   * mark the partition as valid again.
                   */
                  if (!(es->s_state & cpu_to_le16(EXT3_VALID_FS)) &&
                      (sbi->s_mount_state & EXT3_VALID_FS))
                        es->s_state = cpu_to_le16(sbi->s_mount_state);

                  ext3_mark_recovery_complete(sb, es);
            } else {
                  __le32 ret;
                  if ((ret = EXT3_HAS_RO_COMPAT_FEATURE(sb,
                              ~EXT3_FEATURE_RO_COMPAT_SUPP))) {
                        printk(KERN_WARNING "EXT3-fs: %s: couldn't "
                               "remount RDWR because of unsupported "
                               "optional features (%x).\n",
                               sb->s_id, le32_to_cpu(ret));
                        err = -EROFS;
                        goto restore_opts;
                  }
                  /*
                   * Mounting a RDONLY partition read-write, so reread
                   * and store the current valid flag.  (It may have
                   * been changed by e2fsck since we originally mounted
                   * the partition.)
                   */
                  ext3_clear_journal_err(sb, es);
                  sbi->s_mount_state = le16_to_cpu(es->s_state);
                  if ((ret = ext3_group_extend(sb, es, n_blocks_count))) {
                        err = ret;
                        goto restore_opts;
                  }
                  if (!ext3_setup_super (sb, es, 0))
                        sb->s_flags &= ~MS_RDONLY;
            }
      }
#ifdef CONFIG_QUOTA
      /* Release old quota file names */
      for (i = 0; i < MAXQUOTAS; i++)
            if (old_opts.s_qf_names[i] &&
                old_opts.s_qf_names[i] != sbi->s_qf_names[i])
                  kfree(old_opts.s_qf_names[i]);
#endif
      return 0;
restore_opts:
      sb->s_flags = old_sb_flags;
      sbi->s_mount_opt = old_opts.s_mount_opt;
      sbi->s_resuid = old_opts.s_resuid;
      sbi->s_resgid = old_opts.s_resgid;
      sbi->s_commit_interval = old_opts.s_commit_interval;
#ifdef CONFIG_QUOTA
      sbi->s_jquota_fmt = old_opts.s_jquota_fmt;
      for (i = 0; i < MAXQUOTAS; i++) {
            if (sbi->s_qf_names[i] &&
                old_opts.s_qf_names[i] != sbi->s_qf_names[i])
                  kfree(sbi->s_qf_names[i]);
            sbi->s_qf_names[i] = old_opts.s_qf_names[i];
      }
#endif
      return err;
}

static int ext3_statfs (struct dentry * dentry, struct kstatfs * buf)
{
      struct super_block *sb = dentry->d_sb;
      struct ext3_sb_info *sbi = EXT3_SB(sb);
      struct ext3_super_block *es = sbi->s_es;
      ext3_fsblk_t overhead;
      int i;

      if (test_opt (sb, MINIX_DF))
            overhead = 0;
      else {
            unsigned long ngroups;
            ngroups = EXT3_SB(sb)->s_groups_count;
            smp_rmb();

            /*
             * Compute the overhead (FS structures)
             */

            /*
             * All of the blocks before first_data_block are
             * overhead
             */
            overhead = le32_to_cpu(es->s_first_data_block);

            /*
             * Add the overhead attributed to the superblock and
             * block group descriptors.  If the sparse superblocks
             * feature is turned on, then not all groups have this.
             */
            for (i = 0; i < ngroups; i++) {
                  overhead += ext3_bg_has_super(sb, i) +
                        ext3_bg_num_gdb(sb, i);
                  cond_resched();
            }

            /*
             * Every block group has an inode bitmap, a block
             * bitmap, and an inode table.
             */
            overhead += (ngroups * (2 + EXT3_SB(sb)->s_itb_per_group));
      }

      buf->f_type = EXT3_SUPER_MAGIC;
      buf->f_bsize = sb->s_blocksize;
      buf->f_blocks = le32_to_cpu(es->s_blocks_count) - overhead;
      buf->f_bfree = percpu_counter_sum(&sbi->s_freeblocks_counter);
      buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
      if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
            buf->f_bavail = 0;
      buf->f_files = le32_to_cpu(es->s_inodes_count);
      buf->f_ffree = percpu_counter_sum(&sbi->s_freeinodes_counter);
      buf->f_namelen = EXT3_NAME_LEN;
      return 0;
}

/* Helper function for writing quotas on sync - we need to start transaction before quota file
 * is locked for write. Otherwise the are possible deadlocks:
 * Process 1                         Process 2
 * ext3_create()                     quota_sync()
 *   journal_start()                   write_dquot()
 *   DQUOT_INIT()                        down(dqio_mutex)
 *     down(dqio_mutex)                    journal_start()
 *
 */

#ifdef CONFIG_QUOTA

static inline struct inode *dquot_to_inode(struct dquot *dquot)
{
      return sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
}

static int ext3_dquot_initialize(struct inode *inode, int type)
{
      handle_t *handle;
      int ret, err;

      /* We may create quota structure so we need to reserve enough blocks */
      handle = ext3_journal_start(inode, 2*EXT3_QUOTA_INIT_BLOCKS(inode->i_sb));
      if (IS_ERR(handle))
            return PTR_ERR(handle);
      ret = dquot_initialize(inode, type);
      err = ext3_journal_stop(handle);
      if (!ret)
            ret = err;
      return ret;
}

static int ext3_dquot_drop(struct inode *inode)
{
      handle_t *handle;
      int ret, err;

      /* We may delete quota structure so we need to reserve enough blocks */
      handle = ext3_journal_start(inode, 2*EXT3_QUOTA_DEL_BLOCKS(inode->i_sb));
      if (IS_ERR(handle))
            return PTR_ERR(handle);
      ret = dquot_drop(inode);
      err = ext3_journal_stop(handle);
      if (!ret)
            ret = err;
      return ret;
}

static int ext3_write_dquot(struct dquot *dquot)
{
      int ret, err;
      handle_t *handle;
      struct inode *inode;

      inode = dquot_to_inode(dquot);
      handle = ext3_journal_start(inode,
                              EXT3_QUOTA_TRANS_BLOCKS(dquot->dq_sb));
      if (IS_ERR(handle))
            return PTR_ERR(handle);
      ret = dquot_commit(dquot);
      err = ext3_journal_stop(handle);
      if (!ret)
            ret = err;
      return ret;
}

static int ext3_acquire_dquot(struct dquot *dquot)
{
      int ret, err;
      handle_t *handle;

      handle = ext3_journal_start(dquot_to_inode(dquot),
                              EXT3_QUOTA_INIT_BLOCKS(dquot->dq_sb));
      if (IS_ERR(handle))
            return PTR_ERR(handle);
      ret = dquot_acquire(dquot);
      err = ext3_journal_stop(handle);
      if (!ret)
            ret = err;
      return ret;
}

static int ext3_release_dquot(struct dquot *dquot)
{
      int ret, err;
      handle_t *handle;

      handle = ext3_journal_start(dquot_to_inode(dquot),
                              EXT3_QUOTA_DEL_BLOCKS(dquot->dq_sb));
      if (IS_ERR(handle))
            return PTR_ERR(handle);
      ret = dquot_release(dquot);
      err = ext3_journal_stop(handle);
      if (!ret)
            ret = err;
      return ret;
}

static int ext3_mark_dquot_dirty(struct dquot *dquot)
{
      /* Are we journalling quotas? */
      if (EXT3_SB(dquot->dq_sb)->s_qf_names[USRQUOTA] ||
          EXT3_SB(dquot->dq_sb)->s_qf_names[GRPQUOTA]) {
            dquot_mark_dquot_dirty(dquot);
            return ext3_write_dquot(dquot);
      } else {
            return dquot_mark_dquot_dirty(dquot);
      }
}

static int ext3_write_info(struct super_block *sb, int type)
{
      int ret, err;
      handle_t *handle;

      /* Data block + inode block */
      handle = ext3_journal_start(sb->s_root->d_inode, 2);
      if (IS_ERR(handle))
            return PTR_ERR(handle);
      ret = dquot_commit_info(sb, type);
      err = ext3_journal_stop(handle);
      if (!ret)
            ret = err;
      return ret;
}

/*
 * Turn on quotas during mount time - we need to find
 * the quota file and such...
 */
static int ext3_quota_on_mount(struct super_block *sb, int type)
{
      return vfs_quota_on_mount(sb, EXT3_SB(sb)->s_qf_names[type],
                  EXT3_SB(sb)->s_jquota_fmt, type);
}

/*
 * Standard function to be called on quota_on
 */
static int ext3_quota_on(struct super_block *sb, int type, int format_id,
                   char *path)
{
      int err;
      struct nameidata nd;

      if (!test_opt(sb, QUOTA))
            return -EINVAL;
      /* Not journalling quota? */
      if (!EXT3_SB(sb)->s_qf_names[USRQUOTA] &&
          !EXT3_SB(sb)->s_qf_names[GRPQUOTA])
            return vfs_quota_on(sb, type, format_id, path);
      err = path_lookup(path, LOOKUP_FOLLOW, &nd);
      if (err)
            return err;
      /* Quotafile not on the same filesystem? */
      if (nd.mnt->mnt_sb != sb) {
            path_release(&nd);
            return -EXDEV;
      }
      /* Quotafile not of fs root? */
      if (nd.dentry->d_parent->d_inode != sb->s_root->d_inode)
            printk(KERN_WARNING
                  "EXT3-fs: Quota file not on filesystem root. "
                  "Journalled quota will not work.\n");
      path_release(&nd);
      return vfs_quota_on(sb, type, format_id, path);
}

/* Read data from quotafile - avoid pagecache and such because we cannot afford
 * acquiring the locks... As quota files are never truncated and quota code
 * itself serializes the operations (and noone else should touch the files)
 * we don't have to be afraid of races */
static ssize_t ext3_quota_read(struct super_block *sb, int type, char *data,
                         size_t len, loff_t off)
{
      struct inode *inode = sb_dqopt(sb)->files[type];
      sector_t blk = off >> EXT3_BLOCK_SIZE_BITS(sb);
      int err = 0;
      int offset = off & (sb->s_blocksize - 1);
      int tocopy;
      size_t toread;
      struct buffer_head *bh;
      loff_t i_size = i_size_read(inode);

      if (off > i_size)
            return 0;
      if (off+len > i_size)
            len = i_size-off;
      toread = len;
      while (toread > 0) {
            tocopy = sb->s_blocksize - offset < toread ?
                        sb->s_blocksize - offset : toread;
            bh = ext3_bread(NULL, inode, blk, 0, &err);
            if (err)
                  return err;
            if (!bh)    /* A hole? */
                  memset(data, 0, tocopy);
            else
                  memcpy(data, bh->b_data+offset, tocopy);
            brelse(bh);
            offset = 0;
            toread -= tocopy;
            data += tocopy;
            blk++;
      }
      return len;
}

/* Write to quotafile (we know the transaction is already started and has
 * enough credits) */
static ssize_t ext3_quota_write(struct super_block *sb, int type,
                        const char *data, size_t len, loff_t off)
{
      struct inode *inode = sb_dqopt(sb)->files[type];
      sector_t blk = off >> EXT3_BLOCK_SIZE_BITS(sb);
      int err = 0;
      int offset = off & (sb->s_blocksize - 1);
      int tocopy;
      int journal_quota = EXT3_SB(sb)->s_qf_names[type] != NULL;
      size_t towrite = len;
      struct buffer_head *bh;
      handle_t *handle = journal_current_handle();

      mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
      while (towrite > 0) {
            tocopy = sb->s_blocksize - offset < towrite ?
                        sb->s_blocksize - offset : towrite;
            bh = ext3_bread(handle, inode, blk, 1, &err);
            if (!bh)
                  goto out;
            if (journal_quota) {
                  err = ext3_journal_get_write_access(handle, bh);
                  if (err) {
                        brelse(bh);
                        goto out;
                  }
            }
            lock_buffer(bh);
            memcpy(bh->b_data+offset, data, tocopy);
            flush_dcache_page(bh->b_page);
            unlock_buffer(bh);
            if (journal_quota)
                  err = ext3_journal_dirty_metadata(handle, bh);
            else {
                  /* Always do at least ordered writes for quotas */
                  err = ext3_journal_dirty_data(handle, bh);
                  mark_buffer_dirty(bh);
            }
            brelse(bh);
            if (err)
                  goto out;
            offset = 0;
            towrite -= tocopy;
            data += tocopy;
            blk++;
      }
out:
      if (len == towrite)
            return err;
      if (inode->i_size < off+len-towrite) {
            i_size_write(inode, off+len-towrite);
            EXT3_I(inode)->i_disksize = inode->i_size;
      }
      inode->i_version++;
      inode->i_mtime = inode->i_ctime = CURRENT_TIME;
      ext3_mark_inode_dirty(handle, inode);
      mutex_unlock(&inode->i_mutex);
      return len - towrite;
}

#endif

static int ext3_get_sb(struct file_system_type *fs_type,
      int flags, const char *dev_name, void *data, struct vfsmount *mnt)
{
      return get_sb_bdev(fs_type, flags, dev_name, data, ext3_fill_super, mnt);
}

static struct file_system_type ext3_fs_type = {
      .owner            = THIS_MODULE,
      .name       = "ext3",
      .get_sb           = ext3_get_sb,
      .kill_sb    = kill_block_super,
      .fs_flags   = FS_REQUIRES_DEV,
};

static int __init init_ext3_fs(void)
{
      int err = init_ext3_xattr();
      if (err)
            return err;
      err = init_inodecache();
      if (err)
            goto out1;
        err = register_filesystem(&ext3_fs_type);
      if (err)
            goto out;
      return 0;
out:
      destroy_inodecache();
out1:
      exit_ext3_xattr();
      return err;
}

static void __exit exit_ext3_fs(void)
{
      unregister_filesystem(&ext3_fs_type);
      destroy_inodecache();
      exit_ext3_xattr();
}

MODULE_AUTHOR("Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others");
MODULE_DESCRIPTION("Second Extended Filesystem with journaling extensions");
MODULE_LICENSE("GPL");
module_init(init_ext3_fs)
module_exit(exit_ext3_fs)

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