/*
   *   Copyright (C) International Business Machines Corp., 2000-2004
   *   Portions Copyright (C) Christoph Hellwig, 2001-2002
   *
   *   This program is free software;  you can redistribute it and/or modify
   *   it under the terms of the GNU General Public License as published by

   *   the Free Software Foundation; either version 2 of the License, or

   *   (at your option) any later version.

   *

   *   This program is distributed in the hope that it will be useful,
   *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
   *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
   *   the GNU General Public License for more details.
   *
   *   You should have received a copy of the GNU General Public License

   *   along with this program;  if not, write to the Free Software

   *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
   */
  
  #include <linux/fs.h>

  #include <linux/module.h>
  #include <linux/parser.h>
  #include <linux/completion.h>
  #include <linux/vfs.h>

  #include <linux/quotaops.h>

  #include <linux/mount.h>

  #include <linux/moduleparam.h>

  #include <linux/kthread.h>

  #include <linux/posix_acl.h>

  #include <linux/buffer_head.h>

  #include <linux/exportfs.h>

  #include <linux/crc32.h>

  #include <linux/slab.h>

  #include <asm/uaccess.h>

  #include <linux/seq_file.h>

  
  #include "jfs_incore.h"
  #include "jfs_filsys.h"

  #include "jfs_inode.h"

  #include "jfs_metapage.h"
  #include "jfs_superblock.h"
  #include "jfs_dmap.h"
  #include "jfs_imap.h"
  #include "jfs_acl.h"
  #include "jfs_debug.h"
  
  MODULE_DESCRIPTION("The Journaled Filesystem (JFS)");
  MODULE_AUTHOR("Steve Best/Dave Kleikamp/Barry Arndt, IBM");
  MODULE_LICENSE("GPL");

  static struct kmem_cache * jfs_inode_cachep;

  static const struct super_operations jfs_super_operations;

  static const struct export_operations jfs_export_operations;

  static struct file_system_type jfs_fs_type;
  
  #define MAX_COMMIT_THREADS 64
  static int commit_threads = 0;
  module_param(commit_threads, int, 0);
  MODULE_PARM_DESC(commit_threads, "Number of commit threads");

  static struct task_struct *jfsCommitThread[MAX_COMMIT_THREADS];
  struct task_struct *jfsIOthread;
  struct task_struct *jfsSyncThread;

  
  #ifdef CONFIG_JFS_DEBUG
  int jfsloglevel = JFS_LOGLEVEL_WARN;
  module_param(jfsloglevel, int, 0644);
  MODULE_PARM_DESC(jfsloglevel, "Specify JFS loglevel (0, 1 or 2)");
  #endif

  static void jfs_handle_error(struct super_block *sb)
  {
  	struct jfs_sb_info *sbi = JFS_SBI(sb);
  
  	if (sb->s_flags & MS_RDONLY)
  		return;
  
  	updateSuper(sb, FM_DIRTY);
  
  	if (sbi->flag & JFS_ERR_PANIC)
  		panic("JFS (device %s): panic forced after error
  ",
  			sb->s_id);
  	else if (sbi->flag & JFS_ERR_REMOUNT_RO) {
  		jfs_err("ERROR: (device %s): remounting filesystem "
  			"as read-only
  ",
  			sb->s_id);
  		sb->s_flags |= MS_RDONLY;

  	}

  
  	/* nothing is done for continue beyond marking the superblock dirty */
  }
  
  void jfs_error(struct super_block *sb, const char * function, ...)
  {
  	static char error_buf[256];
  	va_list args;
  
  	va_start(args, function);

  	vsnprintf(error_buf, sizeof(error_buf), function, args);

  	va_end(args);
  
  	printk(KERN_ERR "ERROR: (device %s): %s
  ", sb->s_id, error_buf);
  
  	jfs_handle_error(sb);
  }
  
  static struct inode *jfs_alloc_inode(struct super_block *sb)
  {
  	struct jfs_inode_info *jfs_inode;
  
  	jfs_inode = kmem_cache_alloc(jfs_inode_cachep, GFP_NOFS);
  	if (!jfs_inode)
  		return NULL;
  	return &jfs_inode->vfs_inode;
  }

  static void jfs_i_callback(struct rcu_head *head)
  {
  	struct inode *inode = container_of(head, struct inode, i_rcu);
  	struct jfs_inode_info *ji = JFS_IP(inode);
  	INIT_LIST_HEAD(&inode->i_dentry);
  	kmem_cache_free(jfs_inode_cachep, ji);
  }

  static void jfs_destroy_inode(struct inode *inode)
  {
  	struct jfs_inode_info *ji = JFS_IP(inode);

  	BUG_ON(!list_empty(&ji->anon_inode_list));

  	spin_lock_irq(&ji->ag_lock);
  	if (ji->active_ag != -1) {
  		struct bmap *bmap = JFS_SBI(inode->i_sb)->bmap;
  		atomic_dec(&bmap->db_active[ji->active_ag]);
  		ji->active_ag = -1;
  	}
  	spin_unlock_irq(&ji->ag_lock);

  	call_rcu(&inode->i_rcu, jfs_i_callback);

  }

  static int jfs_statfs(struct dentry *dentry, struct kstatfs *buf)

  {

  	struct jfs_sb_info *sbi = JFS_SBI(dentry->d_sb);

  	s64 maxinodes;
  	struct inomap *imap = JFS_IP(sbi->ipimap)->i_imap;
  
  	jfs_info("In jfs_statfs");
  	buf->f_type = JFS_SUPER_MAGIC;
  	buf->f_bsize = sbi->bsize;
  	buf->f_blocks = sbi->bmap->db_mapsize;
  	buf->f_bfree = sbi->bmap->db_nfree;
  	buf->f_bavail = sbi->bmap->db_nfree;
  	/*
  	 * If we really return the number of allocated & free inodes, some
  	 * applications will fail because they won't see enough free inodes.
  	 * We'll try to calculate some guess as to how may inodes we can
  	 * really allocate
  	 *
  	 * buf->f_files = atomic_read(&imap->im_numinos);
  	 * buf->f_ffree = atomic_read(&imap->im_numfree);
  	 */
  	maxinodes = min((s64) atomic_read(&imap->im_numinos) +
  			((sbi->bmap->db_nfree >> imap->im_l2nbperiext)
  			 << L2INOSPEREXT), (s64) 0xffffffffLL);
  	buf->f_files = maxinodes;
  	buf->f_ffree = maxinodes - (atomic_read(&imap->im_numinos) -
  				    atomic_read(&imap->im_numfree));

  	buf->f_fsid.val[0] = (u32)crc32_le(0, sbi->uuid, sizeof(sbi->uuid)/2);
  	buf->f_fsid.val[1] = (u32)crc32_le(0, sbi->uuid + sizeof(sbi->uuid)/2,
  					sizeof(sbi->uuid)/2);

  
  	buf->f_namelen = JFS_NAME_MAX;
  	return 0;
  }
  
  static void jfs_put_super(struct super_block *sb)
  {
  	struct jfs_sb_info *sbi = JFS_SBI(sb);
  	int rc;
  
  	jfs_info("In jfs_put_super");

  	dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);

  	rc = jfs_umount(sb);
  	if (rc)
  		jfs_err("jfs_umount failed with return code %d", rc);

  
  	unload_nls(sbi->nls_tab);

  	truncate_inode_pages(sbi->direct_inode->i_mapping, 0);
  	iput(sbi->direct_inode);

  	kfree(sbi);
  }
  
  enum {
  	Opt_integrity, Opt_nointegrity, Opt_iocharset, Opt_resize,

  	Opt_resize_nosize, Opt_errors, Opt_ignore, Opt_err, Opt_quota,

  	Opt_usrquota, Opt_grpquota, Opt_uid, Opt_gid, Opt_umask

  };

  static const match_table_t tokens = {

  	{Opt_integrity, "integrity"},
  	{Opt_nointegrity, "nointegrity"},
  	{Opt_iocharset, "iocharset=%s"},
  	{Opt_resize, "resize=%u"},
  	{Opt_resize_nosize, "resize"},
  	{Opt_errors, "errors=%s"},
  	{Opt_ignore, "noquota"},
  	{Opt_ignore, "quota"},

  	{Opt_usrquota, "usrquota"},
  	{Opt_grpquota, "grpquota"},

  	{Opt_uid, "uid=%u"},
  	{Opt_gid, "gid=%u"},
  	{Opt_umask, "umask=%u"},

  	{Opt_err, NULL}
  };
  
  static int parse_options(char *options, struct super_block *sb, s64 *newLVSize,
  			 int *flag)
  {
  	void *nls_map = (void *)-1;	/* -1: no change;  NULL: none */
  	char *p;
  	struct jfs_sb_info *sbi = JFS_SBI(sb);
  
  	*newLVSize = 0;
  
  	if (!options)
  		return 1;
  
  	while ((p = strsep(&options, ",")) != NULL) {
  		substring_t args[MAX_OPT_ARGS];
  		int token;
  		if (!*p)
  			continue;
  
  		token = match_token(p, tokens, args);
  		switch (token) {
  		case Opt_integrity:
  			*flag &= ~JFS_NOINTEGRITY;
  			break;
  		case Opt_nointegrity:
  			*flag |= JFS_NOINTEGRITY;
  			break;
  		case Opt_ignore:
  			/* Silently ignore the quota options */
  			/* Don't do anything ;-) */
  			break;
  		case Opt_iocharset:
  			if (nls_map && nls_map != (void *) -1)
  				unload_nls(nls_map);
  			if (!strcmp(args[0].from, "none"))
  				nls_map = NULL;
  			else {
  				nls_map = load_nls(args[0].from);
  				if (!nls_map) {
  					printk(KERN_ERR
  					       "JFS: charset not found
  ");
  					goto cleanup;
  				}
  			}
  			break;
  		case Opt_resize:
  		{
  			char *resize = args[0].from;
  			*newLVSize = simple_strtoull(resize, &resize, 0);
  			break;
  		}
  		case Opt_resize_nosize:
  		{
  			*newLVSize = sb->s_bdev->bd_inode->i_size >>
  				sb->s_blocksize_bits;
  			if (*newLVSize == 0)
  				printk(KERN_ERR
  				       "JFS: Cannot determine volume size
  ");
  			break;
  		}
  		case Opt_errors:
  		{
  			char *errors = args[0].from;
  			if (!errors || !*errors)
  				goto cleanup;
  			if (!strcmp(errors, "continue")) {
  				*flag &= ~JFS_ERR_REMOUNT_RO;
  				*flag &= ~JFS_ERR_PANIC;
  				*flag |= JFS_ERR_CONTINUE;
  			} else if (!strcmp(errors, "remount-ro")) {
  				*flag &= ~JFS_ERR_CONTINUE;
  				*flag &= ~JFS_ERR_PANIC;
  				*flag |= JFS_ERR_REMOUNT_RO;
  			} else if (!strcmp(errors, "panic")) {
  				*flag &= ~JFS_ERR_CONTINUE;
  				*flag &= ~JFS_ERR_REMOUNT_RO;
  				*flag |= JFS_ERR_PANIC;
  			} else {
  				printk(KERN_ERR
  				       "JFS: %s is an invalid error handler
  ",
  				       errors);
  				goto cleanup;
  			}
  			break;
  		}

  #ifdef CONFIG_QUOTA

  		case Opt_quota:
  		case Opt_usrquota:
  			*flag |= JFS_USRQUOTA;
  			break;
  		case Opt_grpquota:
  			*flag |= JFS_GRPQUOTA;
  			break;
  #else
  		case Opt_usrquota:
  		case Opt_grpquota:
  		case Opt_quota:
  			printk(KERN_ERR
  			       "JFS: quota operations not supported
  ");
  			break;
  #endif

  		case Opt_uid:
  		{
  			char *uid = args[0].from;
  			sbi->uid = simple_strtoul(uid, &uid, 0);
  			break;
  		}
  		case Opt_gid:
  		{
  			char *gid = args[0].from;
  			sbi->gid = simple_strtoul(gid, &gid, 0);
  			break;
  		}
  		case Opt_umask:
  		{
  			char *umask = args[0].from;
  			sbi->umask = simple_strtoul(umask, &umask, 8);
  			if (sbi->umask & ~0777) {
  				printk(KERN_ERR
  				       "JFS: Invalid value of umask
  ");
  				goto cleanup;
  			}
  			break;
  		}

  		default:
  			printk("jfs: Unrecognized mount option \"%s\" "
  					" or missing value
  ", p);
  			goto cleanup;
  		}
  	}
  
  	if (nls_map != (void *) -1) {
  		/* Discard old (if remount) */

  		unload_nls(sbi->nls_tab);

  		sbi->nls_tab = nls_map;
  	}
  	return 1;
  
  cleanup:
  	if (nls_map && nls_map != (void *) -1)
  		unload_nls(nls_map);
  	return 0;
  }
  
  static int jfs_remount(struct super_block *sb, int *flags, char *data)
  {
  	s64 newLVSize = 0;
  	int rc = 0;
  	int flag = JFS_SBI(sb)->flag;

  	int ret;

  
  	if (!parse_options(data, sb, &newLVSize, &flag)) {
  		return -EINVAL;
  	}

  	if (newLVSize) {
  		if (sb->s_flags & MS_RDONLY) {
  			printk(KERN_ERR
  		  "JFS: resize requires volume to be mounted read-write
  ");
  			return -EROFS;
  		}
  		rc = jfs_extendfs(sb, newLVSize, 0);

  		if (rc)

  			return rc;
  	}
  
  	if ((sb->s_flags & MS_RDONLY) && !(*flags & MS_RDONLY)) {

  		/*
  		 * Invalidate any previously read metadata.  fsck may have
  		 * changed the on-disk data since we mounted r/o
  		 */
  		truncate_inode_pages(JFS_SBI(sb)->direct_inode->i_mapping, 0);

  		JFS_SBI(sb)->flag = flag;

  		ret = jfs_mount_rw(sb, 1);

  
  		/* mark the fs r/w for quota activity */
  		sb->s_flags &= ~MS_RDONLY;

  		dquot_resume(sb, -1);

  		return ret;

  	}
  	if ((!(sb->s_flags & MS_RDONLY)) && (*flags & MS_RDONLY)) {

  		rc = dquot_suspend(sb, -1);
  		if (rc < 0) {

  			return rc;

  		}

  		rc = jfs_umount_rw(sb);
  		JFS_SBI(sb)->flag = flag;
  		return rc;
  	}
  	if ((JFS_SBI(sb)->flag & JFS_NOINTEGRITY) != (flag & JFS_NOINTEGRITY))
  		if (!(sb->s_flags & MS_RDONLY)) {
  			rc = jfs_umount_rw(sb);

  			if (rc)

  				return rc;

  			JFS_SBI(sb)->flag = flag;

  			ret = jfs_mount_rw(sb, 1);

  			return ret;

  		}
  	JFS_SBI(sb)->flag = flag;
  
  	return 0;
  }
  
  static int jfs_fill_super(struct super_block *sb, void *data, int silent)
  {
  	struct jfs_sb_info *sbi;
  	struct inode *inode;
  	int rc;
  	s64 newLVSize = 0;

  	int flag, ret = -EINVAL;

  
  	jfs_info("In jfs_read_super: s_flags=0x%lx", sb->s_flags);

  	if (!new_valid_dev(sb->s_bdev->bd_dev))

  		return -EOVERFLOW;

  	sbi = kzalloc(sizeof (struct jfs_sb_info), GFP_KERNEL);

  	if (!sbi)

  		return -ENOMEM;

  	sb->s_fs_info = sbi;
  	sbi->sb = sb;

  	sbi->uid = sbi->gid = sbi->umask = -1;

  
  	/* initialize the mount flag and determine the default error handler */
  	flag = JFS_ERR_REMOUNT_RO;

  	if (!parse_options((char *) data, sb, &newLVSize, &flag))
  		goto out_kfree;

  	sbi->flag = flag;
  
  #ifdef CONFIG_JFS_POSIX_ACL
  	sb->s_flags |= MS_POSIXACL;
  #endif
  
  	if (newLVSize) {
  		printk(KERN_ERR "resize option for remount only
  ");

  		goto out_kfree;

  	}
  
  	/*
  	 * Initialize blocksize to 4K.
  	 */
  	sb_set_blocksize(sb, PSIZE);
  
  	/*
  	 * Set method vectors.
  	 */
  	sb->s_op = &jfs_super_operations;
  	sb->s_export_op = &jfs_export_operations;

  #ifdef CONFIG_QUOTA
  	sb->dq_op = &dquot_operations;

  	sb->s_qcop = &dquot_quotactl_ops;

  #endif

  	/*
  	 * Initialize direct-mapping inode/address-space
  	 */
  	inode = new_inode(sb);

  	if (inode == NULL) {
  		ret = -ENOMEM;

  		goto out_unload;

  	}

  	inode->i_ino = 0;

  	inode->i_size = sb->s_bdev->bd_inode->i_size;
  	inode->i_mapping->a_ops = &jfs_metapage_aops;

  	insert_inode_hash(inode);

  	mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS);
  
  	sbi->direct_inode = inode;

  	rc = jfs_mount(sb);
  	if (rc) {
  		if (!silent) {
  			jfs_err("jfs_mount failed w/return code = %d", rc);
  		}

  		goto out_mount_failed;

  	}
  	if (sb->s_flags & MS_RDONLY)
  		sbi->log = NULL;
  	else {
  		rc = jfs_mount_rw(sb, 0);
  		if (rc) {
  			if (!silent) {
  				jfs_err("jfs_mount_rw failed, return code = %d",
  					rc);
  			}
  			goto out_no_rw;
  		}
  	}
  
  	sb->s_magic = JFS_SUPER_MAGIC;

  	if (sbi->mntflag & JFS_OS2)
  		sb->s_d_op = &jfs_ci_dentry_operations;

  	inode = jfs_iget(sb, ROOT_I);
  	if (IS_ERR(inode)) {
  		ret = PTR_ERR(inode);

  		goto out_no_rw;

  	}

  	sb->s_root = d_alloc_root(inode);
  	if (!sb->s_root)
  		goto out_no_root;

  	/* logical blocks are represented by 40 bits in pxd_t, etc. */
  	sb->s_maxbytes = ((u64) sb->s_blocksize) << 40;
  #if BITS_PER_LONG == 32
  	/*
  	 * Page cache is indexed by long.
  	 * I would use MAX_LFS_FILESIZE, but it's only half as big
  	 */

  	sb->s_maxbytes = min(((u64) PAGE_CACHE_SIZE << 32) - 1, (u64)sb->s_maxbytes);

  #endif
  	sb->s_time_gran = 1;
  	return 0;
  
  out_no_root:

  	jfs_err("jfs_read_super: get root dentry failed");
  	iput(inode);

  
  out_no_rw:
  	rc = jfs_umount(sb);
  	if (rc) {
  		jfs_err("jfs_umount failed with return code %d", rc);
  	}

  out_mount_failed:

  	filemap_write_and_wait(sbi->direct_inode->i_mapping);

  	truncate_inode_pages(sbi->direct_inode->i_mapping, 0);
  	make_bad_inode(sbi->direct_inode);
  	iput(sbi->direct_inode);
  	sbi->direct_inode = NULL;

  out_unload:

  	if (sbi->nls_tab)
  		unload_nls(sbi->nls_tab);

  out_kfree:

  	kfree(sbi);

  	return ret;

  }

  static int jfs_freeze(struct super_block *sb)

  {
  	struct jfs_sb_info *sbi = JFS_SBI(sb);
  	struct jfs_log *log = sbi->log;
  
  	if (!(sb->s_flags & MS_RDONLY)) {
  		txQuiesce(sb);
  		lmLogShutdown(log);
  		updateSuper(sb, FM_CLEAN);
  	}

  	return 0;

  }

  static int jfs_unfreeze(struct super_block *sb)

  {
  	struct jfs_sb_info *sbi = JFS_SBI(sb);
  	struct jfs_log *log = sbi->log;
  	int rc = 0;
  
  	if (!(sb->s_flags & MS_RDONLY)) {
  		updateSuper(sb, FM_MOUNT);
  		if ((rc = lmLogInit(log)))
  			jfs_err("jfs_unlock failed with return code %d", rc);
  		else
  			txResume(sb);
  	}

  	return 0;

  }

  static struct dentry *jfs_do_mount(struct file_system_type *fs_type,
  	int flags, const char *dev_name, void *data)

  {

  	return mount_bdev(fs_type, flags, dev_name, data, jfs_fill_super);

  }
  
  static int jfs_sync_fs(struct super_block *sb, int wait)
  {
  	struct jfs_log *log = JFS_SBI(sb)->log;
  
  	/* log == NULL indicates read-only mount */

  	if (log) {

  		jfs_flush_journal(log, wait);

  		jfs_syncpt(log, 0);

  	}

  
  	return 0;
  }

  static int jfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
  {
  	struct jfs_sb_info *sbi = JFS_SBI(vfs->mnt_sb);

  	if (sbi->uid != -1)
  		seq_printf(seq, ",uid=%d", sbi->uid);
  	if (sbi->gid != -1)
  		seq_printf(seq, ",gid=%d", sbi->gid);
  	if (sbi->umask != -1)
  		seq_printf(seq, ",umask=%03o", sbi->umask);

  	if (sbi->flag & JFS_NOINTEGRITY)
  		seq_puts(seq, ",nointegrity");

  	if (sbi->nls_tab)
  		seq_printf(seq, ",iocharset=%s", sbi->nls_tab->charset);
  	if (sbi->flag & JFS_ERR_CONTINUE)
  		seq_printf(seq, ",errors=continue");
  	if (sbi->flag & JFS_ERR_PANIC)
  		seq_printf(seq, ",errors=panic");

  #ifdef CONFIG_QUOTA

  	if (sbi->flag & JFS_USRQUOTA)
  		seq_puts(seq, ",usrquota");
  
  	if (sbi->flag & JFS_GRPQUOTA)
  		seq_puts(seq, ",grpquota");
  #endif
  
  	return 0;
  }

  #ifdef CONFIG_QUOTA
  
  /* 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 no one else should touch the files)

   * we don't have to be afraid of races */
  static ssize_t jfs_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 >> sb->s_blocksize_bits;
  	int err = 0;
  	int offset = off & (sb->s_blocksize - 1);
  	int tocopy;
  	size_t toread;
  	struct buffer_head tmp_bh;
  	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;
  
  		tmp_bh.b_state = 0;
  		tmp_bh.b_size = 1 << inode->i_blkbits;
  		err = jfs_get_block(inode, blk, &tmp_bh, 0);
  		if (err)
  			return err;
  		if (!buffer_mapped(&tmp_bh))	/* A hole? */
  			memset(data, 0, tocopy);
  		else {
  			bh = sb_bread(sb, tmp_bh.b_blocknr);
  			if (!bh)
  				return -EIO;
  			memcpy(data, bh->b_data+offset, tocopy);
  			brelse(bh);
  		}
  		offset = 0;
  		toread -= tocopy;
  		data += tocopy;
  		blk++;
  	}
  	return len;
  }
  
  /* Write to quotafile */
  static ssize_t jfs_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 >> sb->s_blocksize_bits;
  	int err = 0;
  	int offset = off & (sb->s_blocksize - 1);
  	int tocopy;
  	size_t towrite = len;
  	struct buffer_head tmp_bh;
  	struct buffer_head *bh;
  
  	mutex_lock(&inode->i_mutex);
  	while (towrite > 0) {
  		tocopy = sb->s_blocksize - offset < towrite ?
  				sb->s_blocksize - offset : towrite;
  
  		tmp_bh.b_state = 0;

  		tmp_bh.b_size = 1 << inode->i_blkbits;

  		err = jfs_get_block(inode, blk, &tmp_bh, 1);
  		if (err)
  			goto out;
  		if (offset || tocopy != sb->s_blocksize)
  			bh = sb_bread(sb, tmp_bh.b_blocknr);
  		else
  			bh = sb_getblk(sb, tmp_bh.b_blocknr);
  		if (!bh) {
  			err = -EIO;
  			goto out;
  		}
  		lock_buffer(bh);
  		memcpy(bh->b_data+offset, data, tocopy);
  		flush_dcache_page(bh->b_page);
  		set_buffer_uptodate(bh);
  		mark_buffer_dirty(bh);
  		unlock_buffer(bh);
  		brelse(bh);
  		offset = 0;
  		towrite -= tocopy;
  		data += tocopy;
  		blk++;
  	}
  out:

  	if (len == towrite) {
  		mutex_unlock(&inode->i_mutex);

  		return err;

  	}

  	if (inode->i_size < off+len-towrite)
  		i_size_write(inode, off+len-towrite);
  	inode->i_version++;
  	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
  	mark_inode_dirty(inode);
  	mutex_unlock(&inode->i_mutex);
  	return len - towrite;
  }
  
  #endif

  static const struct super_operations jfs_super_operations = {

  	.alloc_inode	= jfs_alloc_inode,
  	.destroy_inode	= jfs_destroy_inode,

  	.dirty_inode	= jfs_dirty_inode,
  	.write_inode	= jfs_write_inode,

  	.evict_inode	= jfs_evict_inode,

  	.put_super	= jfs_put_super,
  	.sync_fs	= jfs_sync_fs,

  	.freeze_fs	= jfs_freeze,
  	.unfreeze_fs	= jfs_unfreeze,

  	.statfs		= jfs_statfs,
  	.remount_fs	= jfs_remount,

  	.show_options	= jfs_show_options,
  #ifdef CONFIG_QUOTA
  	.quota_read	= jfs_quota_read,
  	.quota_write	= jfs_quota_write,
  #endif

  };

  static const struct export_operations jfs_export_operations = {

  	.fh_to_dentry	= jfs_fh_to_dentry,
  	.fh_to_parent	= jfs_fh_to_parent,

  	.get_parent	= jfs_get_parent,
  };
  
  static struct file_system_type jfs_fs_type = {
  	.owner		= THIS_MODULE,
  	.name		= "jfs",

  	.mount		= jfs_do_mount,

  	.kill_sb	= kill_block_super,
  	.fs_flags	= FS_REQUIRES_DEV,
  };

  static void init_once(void *foo)

  {
  	struct jfs_inode_info *jfs_ip = (struct jfs_inode_info *) foo;

  	memset(jfs_ip, 0, sizeof(struct jfs_inode_info));
  	INIT_LIST_HEAD(&jfs_ip->anon_inode_list);
  	init_rwsem(&jfs_ip->rdwrlock);
  	mutex_init(&jfs_ip->commit_mutex);
  	init_rwsem(&jfs_ip->xattr_sem);
  	spin_lock_init(&jfs_ip->ag_lock);
  	jfs_ip->active_ag = -1;

  	inode_init_once(&jfs_ip->vfs_inode);

  }
  
  static int __init init_jfs_fs(void)
  {
  	int i;
  	int rc;
  
  	jfs_inode_cachep =

  	    kmem_cache_create("jfs_ip", sizeof(struct jfs_inode_info), 0,

  			    SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,

  			    init_once);

  	if (jfs_inode_cachep == NULL)
  		return -ENOMEM;
  
  	/*
  	 * Metapage initialization
  	 */
  	rc = metapage_init();
  	if (rc) {
  		jfs_err("metapage_init failed w/rc = %d", rc);
  		goto free_slab;
  	}
  
  	/*
  	 * Transaction Manager initialization
  	 */
  	rc = txInit();
  	if (rc) {
  		jfs_err("txInit failed w/rc = %d", rc);
  		goto free_metapage;
  	}
  
  	/*
  	 * I/O completion thread (endio)
  	 */

  	jfsIOthread = kthread_run(jfsIOWait, NULL, "jfsIO");
  	if (IS_ERR(jfsIOthread)) {
  		rc = PTR_ERR(jfsIOthread);
  		jfs_err("init_jfs_fs: fork failed w/rc = %d", rc);

  		goto end_txmngr;
  	}

  
  	if (commit_threads < 1)
  		commit_threads = num_online_cpus();
  	if (commit_threads > MAX_COMMIT_THREADS)
  		commit_threads = MAX_COMMIT_THREADS;
  
  	for (i = 0; i < commit_threads; i++) {

  		jfsCommitThread[i] = kthread_run(jfs_lazycommit, NULL, "jfsCommit");
  		if (IS_ERR(jfsCommitThread[i])) {
  			rc = PTR_ERR(jfsCommitThread[i]);
  			jfs_err("init_jfs_fs: fork failed w/rc = %d", rc);

  			commit_threads = i;
  			goto kill_committask;
  		}

  	}

  	jfsSyncThread = kthread_run(jfs_sync, NULL, "jfsSync");
  	if (IS_ERR(jfsSyncThread)) {
  		rc = PTR_ERR(jfsSyncThread);
  		jfs_err("init_jfs_fs: fork failed w/rc = %d", rc);

  		goto kill_committask;
  	}

  
  #ifdef PROC_FS_JFS
  	jfs_proc_init();
  #endif
  
  	return register_filesystem(&jfs_fs_type);
  
  kill_committask:

  	for (i = 0; i < commit_threads; i++)

  		kthread_stop(jfsCommitThread[i]);
  	kthread_stop(jfsIOthread);

  end_txmngr:
  	txExit();
  free_metapage:
  	metapage_exit();
  free_slab:
  	kmem_cache_destroy(jfs_inode_cachep);
  	return rc;
  }
  
  static void __exit exit_jfs_fs(void)
  {
  	int i;
  
  	jfs_info("exit_jfs_fs called");

  	txExit();
  	metapage_exit();

  
  	kthread_stop(jfsIOthread);

  	for (i = 0; i < commit_threads; i++)

  		kthread_stop(jfsCommitThread[i]);
  	kthread_stop(jfsSyncThread);

  #ifdef PROC_FS_JFS
  	jfs_proc_clean();
  #endif
  	unregister_filesystem(&jfs_fs_type);
  	kmem_cache_destroy(jfs_inode_cachep);
  }
  
  module_init(init_jfs_fs)
  module_exit(exit_jfs_fs)