text: /*
   *  linux/fs/ext4/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/vmalloc.h>
  #include <linux/jbd2.h>
  #include <linux/slab.h>
  #include <linux/init.h>
  #include <linux/blkdev.h>
  #include <linux/parser.h>
  #include <linux/buffer_head.h>
  #include <linux/exportfs.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 <linux/proc_fs.h>
  #include <linux/ctype.h>
  #include <linux/log2.h>
  #include <linux/crc16.h>
  #include <linux/cleancache.h>
  #include <asm/uaccess.h>
  
  #include <linux/kthread.h>
  #include <linux/freezer.h>
  
  #include "ext4.h"
  #include "ext4_jbd2.h"
  #include "xattr.h"
  #include "acl.h"
  #include "mballoc.h"
  
  #define CREATE_TRACE_POINTS
  #include <trace/events/ext4.h>
  
  static struct proc_dir_entry *ext4_proc_root;
  static struct kset *ext4_kset;
  static struct ext4_lazy_init *ext4_li_info;
  static struct mutex ext4_li_mtx;
  static struct ext4_features *ext4_feat;
  
  static int ext4_load_journal(struct super_block *, struct ext4_super_block *,
  			     unsigned long journal_devnum);
  static int ext4_commit_super(struct super_block *sb, int sync);
  static void ext4_mark_recovery_complete(struct super_block *sb,
  					struct ext4_super_block *es);
  static void ext4_clear_journal_err(struct super_block *sb,
  				   struct ext4_super_block *es);
  static int ext4_sync_fs(struct super_block *sb, int wait);
  static const char *ext4_decode_error(struct super_block *sb, int errno,
  				     char nbuf[16]);
  static int ext4_remount(struct super_block *sb, int *flags, char *data);
  static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf);
  static int ext4_unfreeze(struct super_block *sb);
  static void ext4_write_super(struct super_block *sb);
  static int ext4_freeze(struct super_block *sb);
  static struct dentry *ext4_mount(struct file_system_type *fs_type, int flags,
  		       const char *dev_name, void *data);
  static inline int ext2_feature_set_ok(struct super_block *sb);
  static inline int ext3_feature_set_ok(struct super_block *sb);
  static int ext4_feature_set_ok(struct super_block *sb, int readonly);
  static void ext4_destroy_lazyinit_thread(void);
  static void ext4_unregister_li_request(struct super_block *sb);
  static void ext4_clear_request_list(void);
  
  #if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
  static struct file_system_type ext2_fs_type = {
  	.owner		= THIS_MODULE,
  	.name		= "ext2",
  	.mount		= ext4_mount,
  	.kill_sb	= kill_block_super,
  	.fs_flags	= FS_REQUIRES_DEV,
  };
  #define IS_EXT2_SB(sb) ((sb)->s_bdev->bd_holder == &ext2_fs_type)
  #else
  #define IS_EXT2_SB(sb) (0)
  #endif
  
  #if !defined(CONFIG_EXT3_FS) && !defined(CONFIG_EXT3_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
  static struct file_system_type ext3_fs_type = {
  	.owner		= THIS_MODULE,
  	.name		= "ext3",
  	.mount		= ext4_mount,
  	.kill_sb	= kill_block_super,
  	.fs_flags	= FS_REQUIRES_DEV,
  };
  #define IS_EXT3_SB(sb) ((sb)->s_bdev->bd_holder == &ext3_fs_type)
  #else
  #define IS_EXT3_SB(sb) (0)
  #endif
  
  ext4_fsblk_t ext4_block_bitmap(struct super_block *sb,
  			       struct ext4_group_desc *bg)
  {
  	return le32_to_cpu(bg->bg_block_bitmap_lo) |
  		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
  		 (ext4_fsblk_t)le32_to_cpu(bg->bg_block_bitmap_hi) << 32 : 0);
  }
  
  ext4_fsblk_t ext4_inode_bitmap(struct super_block *sb,
  			       struct ext4_group_desc *bg)
  {
  	return le32_to_cpu(bg->bg_inode_bitmap_lo) |
  		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
  		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_bitmap_hi) << 32 : 0);
  }
  
  ext4_fsblk_t ext4_inode_table(struct super_block *sb,
  			      struct ext4_group_desc *bg)
  {
  	return le32_to_cpu(bg->bg_inode_table_lo) |
  		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
  		 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_table_hi) << 32 : 0);
  }
  
  __u32 ext4_free_blks_count(struct super_block *sb,
  			      struct ext4_group_desc *bg)
  {
  	return le16_to_cpu(bg->bg_free_blocks_count_lo) |
  		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
  		 (__u32)le16_to_cpu(bg->bg_free_blocks_count_hi) << 16 : 0);
  }
  
  __u32 ext4_free_inodes_count(struct super_block *sb,
  			      struct ext4_group_desc *bg)
  {
  	return le16_to_cpu(bg->bg_free_inodes_count_lo) |
  		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
  		 (__u32)le16_to_cpu(bg->bg_free_inodes_count_hi) << 16 : 0);
  }
  
  __u32 ext4_used_dirs_count(struct super_block *sb,
  			      struct ext4_group_desc *bg)
  {
  	return le16_to_cpu(bg->bg_used_dirs_count_lo) |
  		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
  		 (__u32)le16_to_cpu(bg->bg_used_dirs_count_hi) << 16 : 0);
  }
  
  __u32 ext4_itable_unused_count(struct super_block *sb,
  			      struct ext4_group_desc *bg)
  {
  	return le16_to_cpu(bg->bg_itable_unused_lo) |
  		(EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
  		 (__u32)le16_to_cpu(bg->bg_itable_unused_hi) << 16 : 0);
  }
  
  void ext4_block_bitmap_set(struct super_block *sb,
  			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
  {
  	bg->bg_block_bitmap_lo = cpu_to_le32((u32)blk);
  	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
  		bg->bg_block_bitmap_hi = cpu_to_le32(blk >> 32);
  }
  
  void ext4_inode_bitmap_set(struct super_block *sb,
  			   struct ext4_group_desc *bg, ext4_fsblk_t blk)
  {
  	bg->bg_inode_bitmap_lo  = cpu_to_le32((u32)blk);
  	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
  		bg->bg_inode_bitmap_hi = cpu_to_le32(blk >> 32);
  }
  
  void ext4_inode_table_set(struct super_block *sb,
  			  struct ext4_group_desc *bg, ext4_fsblk_t blk)
  {
  	bg->bg_inode_table_lo = cpu_to_le32((u32)blk);
  	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
  		bg->bg_inode_table_hi = cpu_to_le32(blk >> 32);
  }
  
  void ext4_free_blks_set(struct super_block *sb,
  			  struct ext4_group_desc *bg, __u32 count)
  {
  	bg->bg_free_blocks_count_lo = cpu_to_le16((__u16)count);
  	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
  		bg->bg_free_blocks_count_hi = cpu_to_le16(count >> 16);
  }
  
  void ext4_free_inodes_set(struct super_block *sb,
  			  struct ext4_group_desc *bg, __u32 count)
  {
  	bg->bg_free_inodes_count_lo = cpu_to_le16((__u16)count);
  	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
  		bg->bg_free_inodes_count_hi = cpu_to_le16(count >> 16);
  }
  
  void ext4_used_dirs_set(struct super_block *sb,
  			  struct ext4_group_desc *bg, __u32 count)
  {
  	bg->bg_used_dirs_count_lo = cpu_to_le16((__u16)count);
  	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
  		bg->bg_used_dirs_count_hi = cpu_to_le16(count >> 16);
  }
  
  void ext4_itable_unused_set(struct super_block *sb,
  			  struct ext4_group_desc *bg, __u32 count)
  {
  	bg->bg_itable_unused_lo = cpu_to_le16((__u16)count);
  	if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
  		bg->bg_itable_unused_hi = cpu_to_le16(count >> 16);
  }
  
  /* Just increment the non-pointer handle value */
  static handle_t *ext4_get_nojournal(void)
  {
  	handle_t *handle = current->journal_info;
  	unsigned long ref_cnt = (unsigned long)handle;
  
  	ref_cnt++;
  	handle = (handle_t *)ref_cnt;
  
  	current->journal_info = handle;
  	return handle;
  }
  
  /* Decrement the non-pointer handle value */
  static void ext4_put_nojournal(handle_t *handle)
  {
  	unsigned long ref_cnt = (unsigned long)handle;
  
  	ref_cnt--;
  	handle = (handle_t *)ref_cnt;
  
  	current->journal_info = handle;
  }
  
  /*
   * Wrappers for jbd2_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.
   *
   * To avoid j_barrier hold in userspace when a user calls freeze(),
   * ext4 prevents a new handle from being started by s_frozen, which
   * is in an upper layer.
   */
  handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks)
  {
  	journal_t *journal;
  	handle_t  *handle;
  
  	if (sb->s_flags & MS_RDONLY)
  		return ERR_PTR(-EROFS);
  
  	journal = EXT4_SB(sb)->s_journal;
  	handle = ext4_journal_current_handle();
  
  	/*
  	 * If a handle has been started, it should be allowed to
  	 * finish, otherwise deadlock could happen between freeze
  	 * and others(e.g. truncate) due to the restart of the
  	 * journal handle if the filesystem is forzen and active
  	 * handles are not stopped.
  	 */
  	if (!handle)
  		vfs_check_frozen(sb, SB_FREEZE_TRANS);
  
  	if (!journal)
  		return ext4_get_nojournal();
  	/*
  	 * 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.
  	 */
  	if (is_journal_aborted(journal)) {
  		ext4_abort(sb, "Detected aborted journal");
  		return ERR_PTR(-EROFS);
  	}
  	return jbd2_journal_start(journal, nblocks);
  }
  
  /*
   * The only special thing we need to do here is to make sure that all
   * jbd2_journal_stop calls result in the superblock being marked dirty, so
   * that sync() will call the filesystem's write_super callback if
   * appropriate.
   */
  int __ext4_journal_stop(const char *where, unsigned int line, handle_t *handle)
  {
  	struct super_block *sb;
  	int err;
  	int rc;
  
  	if (!ext4_handle_valid(handle)) {
  		ext4_put_nojournal(handle);
  		return 0;
  	}
  	sb = handle->h_transaction->t_journal->j_private;
  	err = handle->h_err;
  	rc = jbd2_journal_stop(handle);
  
  	if (!err)
  		err = rc;
  	if (err)
  		__ext4_std_error(sb, where, line, err);
  	return err;
  }
  
  void ext4_journal_abort_handle(const char *caller, unsigned int line,
  			       const char *err_fn, struct buffer_head *bh,
  			       handle_t *handle, int err)
  {
  	char nbuf[16];
  	const char *errstr = ext4_decode_error(NULL, err, nbuf);
  
  	if (!handle->h_err)
  		handle->h_err = err;
  
  	if (is_handle_aborted(handle))
  		return;
  
  	printk(KERN_ERR "%s:%d: aborting transaction: %s in %s\n",
  	       caller, line, errstr, err_fn);
  
  	jbd2_journal_abort_handle(handle);
  }
  
  static void __save_error_info(struct super_block *sb, const char *func,
  			    unsigned int line)
  {
  	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
  
  	EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
  	es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
  	es->s_last_error_time = cpu_to_le32(get_seconds());
  	strncpy(es->s_last_error_func, func, sizeof(es->s_last_error_func));
  	es->s_last_error_line = cpu_to_le32(line);
  	if (!es->s_first_error_time) {
  		es->s_first_error_time = es->s_last_error_time;
  		strncpy(es->s_first_error_func, func,
  			sizeof(es->s_first_error_func));
  		es->s_first_error_line = cpu_to_le32(line);
  		es->s_first_error_ino = es->s_last_error_ino;
  		es->s_first_error_block = es->s_last_error_block;
  	}
  	/*
  	 * Start the daily error reporting function if it hasn't been
  	 * started already
  	 */
  	if (!es->s_error_count)
  		mod_timer(&EXT4_SB(sb)->s_err_report, jiffies + 24*60*60*HZ);
  	es->s_error_count = cpu_to_le32(le32_to_cpu(es->s_error_count) + 1);
  }
  
  static void save_error_info(struct super_block *sb, const char *func,
  			    unsigned int line)
  {
  	__save_error_info(sb, func, line);
  	ext4_commit_super(sb, 1);
  }
  
  /* 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 ext4, 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 jbd2_journal_abort() error code to record an error in
   * the journal instead.  On recovery, the journal will complain about
   * that error until we've noted it down and cleared it.
   */
  
  static void ext4_handle_error(struct super_block *sb)
  {
  	if (sb->s_flags & MS_RDONLY)
  		return;
  
  	if (!test_opt(sb, ERRORS_CONT)) {
  		journal_t *journal = EXT4_SB(sb)->s_journal;
  
  		EXT4_SB(sb)->s_mount_flags |= EXT4_MF_FS_ABORTED;
  		if (journal)
  			jbd2_journal_abort(journal, -EIO);
  	}
  	if (test_opt(sb, ERRORS_RO)) {
  		ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
  		sb->s_flags |= MS_RDONLY;
  	}
  	if (test_opt(sb, ERRORS_PANIC))
  		panic("EXT4-fs (device %s): panic forced after error\n",
  			sb->s_id);
  }
  
  void __ext4_error(struct super_block *sb, const char *function,
  		  unsigned int line, const char *fmt, ...)
  {
  	struct va_format vaf;
  	va_list args;
  
  	va_start(args, fmt);
  	vaf.fmt = fmt;
  	vaf.va = &args;
  	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: comm %s: %pV\n",
  	       sb->s_id, function, line, current->comm, &vaf);
  	va_end(args);
  	save_error_info(sb, function, line);
  
  	ext4_handle_error(sb);
  }
  
  void ext4_error_inode(struct inode *inode, const char *function,
  		      unsigned int line, ext4_fsblk_t block,
  		      const char *fmt, ...)
  {
  	va_list args;
  	struct va_format vaf;
  	struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
  
  	es->s_last_error_ino = cpu_to_le32(inode->i_ino);
  	es->s_last_error_block = cpu_to_le64(block);
  	save_error_info(inode->i_sb, function, line);
  	va_start(args, fmt);
  	vaf.fmt = fmt;
  	vaf.va = &args;
  	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: inode #%lu: ",
  	       inode->i_sb->s_id, function, line, inode->i_ino);
  	if (block)
  		printk(KERN_CONT "block %llu: ", block);
  	printk(KERN_CONT "comm %s: %pV\n", current->comm, &vaf);
  	va_end(args);
  
  	ext4_handle_error(inode->i_sb);
  }
  
  void ext4_error_file(struct file *file, const char *function,
  		     unsigned int line, ext4_fsblk_t block,
  		     const char *fmt, ...)
  {
  	va_list args;
  	struct va_format vaf;
  	struct ext4_super_block *es;
  	struct inode *inode = file->f_dentry->d_inode;
  	char pathname[80], *path;
  
  	es = EXT4_SB(inode->i_sb)->s_es;
  	es->s_last_error_ino = cpu_to_le32(inode->i_ino);
  	save_error_info(inode->i_sb, function, line);
  	path = d_path(&(file->f_path), pathname, sizeof(pathname));
  	if (IS_ERR(path))
  		path = "(unknown)";
  	printk(KERN_CRIT
  	       "EXT4-fs error (device %s): %s:%d: inode #%lu: ",
  	       inode->i_sb->s_id, function, line, inode->i_ino);
  	if (block)
  		printk(KERN_CONT "block %llu: ", block);
  	va_start(args, fmt);
  	vaf.fmt = fmt;
  	vaf.va = &args;
  	printk(KERN_CONT "comm %s: path %s: %pV\n", current->comm, path, &vaf);
  	va_end(args);
  
  	ext4_handle_error(inode->i_sb);
  }
  
  static const char *ext4_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 || (EXT4_SB(sb)->s_journal &&
  			    EXT4_SB(sb)->s_journal->j_flags & JBD2_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;
  }
  
  /* __ext4_std_error decodes expected errors from journaling functions
   * automatically and invokes the appropriate error response.  */
  
  void __ext4_std_error(struct super_block *sb, const char *function,
  		      unsigned int line, 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 = ext4_decode_error(sb, errno, nbuf);
  	printk(KERN_CRIT "EXT4-fs error (device %s) in %s:%d: %s\n",
  	       sb->s_id, function, line, errstr);
  	save_error_info(sb, function, line);
  
  	ext4_handle_error(sb);
  }
  
  /*
   * ext4_abort is a much stronger failure handler than ext4_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 __ext4_abort(struct super_block *sb, const char *function,
  		unsigned int line, const char *fmt, ...)
  {
  	va_list args;
  
  	save_error_info(sb, function, line);
  	va_start(args, fmt);
  	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: ", sb->s_id,
  	       function, line);
  	vprintk(fmt, args);
  	printk("\n");
  	va_end(args);
  
  	if ((sb->s_flags & MS_RDONLY) == 0) {
  		ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
  		sb->s_flags |= MS_RDONLY;
  		EXT4_SB(sb)->s_mount_flags |= EXT4_MF_FS_ABORTED;
  		if (EXT4_SB(sb)->s_journal)
  			jbd2_journal_abort(EXT4_SB(sb)->s_journal, -EIO);
  		save_error_info(sb, function, line);
  	}
  	if (test_opt(sb, ERRORS_PANIC))
  		panic("EXT4-fs panic from previous error\n");
  }
  
  void ext4_msg(struct super_block *sb, const char *prefix, const char *fmt, ...)
  {
  	struct va_format vaf;
  	va_list args;
  
  	va_start(args, fmt);
  	vaf.fmt = fmt;
  	vaf.va = &args;
  	printk("%sEXT4-fs (%s): %pV\n", prefix, sb->s_id, &vaf);
  	va_end(args);
  }
  
  void __ext4_warning(struct super_block *sb, const char *function,
  		    unsigned int line, const char *fmt, ...)
  {
  	struct va_format vaf;
  	va_list args;
  
  	va_start(args, fmt);
  	vaf.fmt = fmt;
  	vaf.va = &args;
  	printk(KERN_WARNING "EXT4-fs warning (device %s): %s:%d: %pV\n",
  	       sb->s_id, function, line, &vaf);
  	va_end(args);
  }
  
  void __ext4_grp_locked_error(const char *function, unsigned int line,
  			     struct super_block *sb, ext4_group_t grp,
  			     unsigned long ino, ext4_fsblk_t block,
  			     const char *fmt, ...)
  __releases(bitlock)
  __acquires(bitlock)
  {
  	struct va_format vaf;
  	va_list args;
  	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
  
  	es->s_last_error_ino = cpu_to_le32(ino);
  	es->s_last_error_block = cpu_to_le64(block);
  	__save_error_info(sb, function, line);
  
  	va_start(args, fmt);
  
  	vaf.fmt = fmt;
  	vaf.va = &args;
  	printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: group %u, ",
  	       sb->s_id, function, line, grp);
  	if (ino)
  		printk(KERN_CONT "inode %lu: ", ino);
  	if (block)
  		printk(KERN_CONT "block %llu:", (unsigned long long) block);
  	printk(KERN_CONT "%pV\n", &vaf);
  	va_end(args);
  
  	if (test_opt(sb, ERRORS_CONT)) {
  		ext4_commit_super(sb, 0);
  		return;
  	}
  
  	ext4_unlock_group(sb, grp);
  	ext4_handle_error(sb);
  	/*
  	 * We only get here in the ERRORS_RO case; relocking the group
  	 * may be dangerous, but nothing bad will happen since the
  	 * filesystem will have already been marked read/only and the
  	 * journal has been aborted.  We return 1 as a hint to callers
  	 * who might what to use the return value from
  	 * ext4_grp_locked_error() to distinguish between the
  	 * ERRORS_CONT and ERRORS_RO case, and perhaps return more
  	 * aggressively from the ext4 function in question, with a
  	 * more appropriate error code.
  	 */
  	ext4_lock_group(sb, grp);
  	return;
  }
  
  void ext4_update_dynamic_rev(struct super_block *sb)
  {
  	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
  
  	if (le32_to_cpu(es->s_rev_level) > EXT4_GOOD_OLD_REV)
  		return;
  
  	ext4_warning(sb,
  		     "updating to rev %d because of new feature flag, "
  		     "running e2fsck is recommended",
  		     EXT4_DYNAMIC_REV);
  
  	es->s_first_ino = cpu_to_le32(EXT4_GOOD_OLD_FIRST_INO);
  	es->s_inode_size = cpu_to_le16(EXT4_GOOD_OLD_INODE_SIZE);
  	es->s_rev_level = cpu_to_le32(EXT4_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 *ext4_blkdev_get(dev_t dev, struct super_block *sb)
  {
  	struct block_device *bdev;
  	char b[BDEVNAME_SIZE];
  
  	bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, sb);
  	if (IS_ERR(bdev))
  		goto fail;
  	return bdev;
  
  fail:
  	ext4_msg(sb, KERN_ERR, "failed to open journal device %s: %ld",
  			__bdevname(dev, b), PTR_ERR(bdev));
  	return NULL;
  }
  
  /*
   * Release the journal device
   */
  static int ext4_blkdev_put(struct block_device *bdev)
  {
  	return blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
  }
  
  static int ext4_blkdev_remove(struct ext4_sb_info *sbi)
  {
  	struct block_device *bdev;
  	int ret = -ENODEV;
  
  	bdev = sbi->journal_bdev;
  	if (bdev) {
  		ret = ext4_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 ext4_inode_info, i_orphan)->vfs_inode;
  }
  
  static void dump_orphan_list(struct super_block *sb, struct ext4_sb_info *sbi)
  {
  	struct list_head *l;
  
  	ext4_msg(sb, KERN_ERR, "sb orphan head is %d",
  		 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:%lu 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 ext4_put_super(struct super_block *sb)
  {
  	struct ext4_sb_info *sbi = EXT4_SB(sb);
  	struct ext4_super_block *es = sbi->s_es;
  	int i, err;
  
  	ext4_unregister_li_request(sb);
  	dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
  
  	flush_workqueue(sbi->dio_unwritten_wq);
  	destroy_workqueue(sbi->dio_unwritten_wq);
  
  	lock_super(sb);
  	if (sb->s_dirt)
  		ext4_commit_super(sb, 1);
  
  	if (sbi->s_journal) {
  		err = jbd2_journal_destroy(sbi->s_journal);
  		sbi->s_journal = NULL;
  		if (err < 0)
  			ext4_abort(sb, "Couldn't clean up the journal");
  	}
  
  	del_timer(&sbi->s_err_report);
  	ext4_release_system_zone(sb);
  	ext4_mb_release(sb);
  	ext4_ext_release(sb);
  	ext4_xattr_put_super(sb);
  
  	if (!(sb->s_flags & MS_RDONLY)) {
  		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
  		es->s_state = cpu_to_le16(sbi->s_mount_state);
  		ext4_commit_super(sb, 1);
  	}
  	if (sbi->s_proc) {
  		remove_proc_entry(sb->s_id, ext4_proc_root);
  	}
  	kobject_del(&sbi->s_kobj);
  
  	for (i = 0; i < sbi->s_gdb_count; i++)
  		brelse(sbi->s_group_desc[i]);
  	kfree(sbi->s_group_desc);
  	if (is_vmalloc_addr(sbi->s_flex_groups))
  		vfree(sbi->s_flex_groups);
  	else
  		kfree(sbi->s_flex_groups);
  	percpu_counter_destroy(&sbi->s_freeblocks_counter);
  	percpu_counter_destroy(&sbi->s_freeinodes_counter);
  	percpu_counter_destroy(&sbi->s_dirs_counter);
  	percpu_counter_destroy(&sbi->s_dirtyblocks_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);
  	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);
  		ext4_blkdev_remove(sbi);
  	}
  	if (sbi->s_mmp_tsk)
  		kthread_stop(sbi->s_mmp_tsk);
  	sb->s_fs_info = NULL;
  	/*
  	 * Now that we are completely done shutting down the
  	 * superblock, we need to actually destroy the kobject.
  	 */
  	unlock_super(sb);
  	kobject_put(&sbi->s_kobj);
  	wait_for_completion(&sbi->s_kobj_unregister);
  	kfree(sbi->s_blockgroup_lock);
  	kfree(sbi);
  }
  
  static struct kmem_cache *ext4_inode_cachep;
  
  /*
   * Called inside transaction, so use GFP_NOFS
   */
  static struct inode *ext4_alloc_inode(struct super_block *sb)
  {
  	struct ext4_inode_info *ei;
  
  	ei = kmem_cache_alloc(ext4_inode_cachep, GFP_NOFS);
  	if (!ei)
  		return NULL;
  
  	ei->vfs_inode.i_version = 1;
  	ei->vfs_inode.i_data.writeback_index = 0;
  	memset(&ei->i_cached_extent, 0, sizeof(struct ext4_ext_cache));
  	INIT_LIST_HEAD(&ei->i_prealloc_list);
  	spin_lock_init(&ei->i_prealloc_lock);
  	ei->i_reserved_data_blocks = 0;
  	ei->i_reserved_meta_blocks = 0;
  	ei->i_allocated_meta_blocks = 0;
  	ei->i_da_metadata_calc_len = 0;
  	ei->i_da_metadata_calc_last_lblock = 0;
  	spin_lock_init(&(ei->i_block_reservation_lock));
  #ifdef CONFIG_QUOTA
  	ei->i_reserved_quota = 0;
  #endif
  	ei->jinode = NULL;
  	INIT_LIST_HEAD(&ei->i_completed_io_list);
  	spin_lock_init(&ei->i_completed_io_lock);
  	ei->cur_aio_dio = NULL;
  	ei->i_sync_tid = 0;
  	ei->i_datasync_tid = 0;
  	atomic_set(&ei->i_ioend_count, 0);
  	atomic_set(&ei->i_aiodio_unwritten, 0);
  
  	return &ei->vfs_inode;
  }
  
  static int ext4_drop_inode(struct inode *inode)
  {
  	int drop = generic_drop_inode(inode);
  
  	trace_ext4_drop_inode(inode, drop);
  	return drop;
  }
  
  static void ext4_i_callback(struct rcu_head *head)
  {
  	struct inode *inode = container_of(head, struct inode, i_rcu);
  	INIT_LIST_HEAD(&inode->i_dentry);
  	kmem_cache_free(ext4_inode_cachep, EXT4_I(inode));
  }
  
  static void ext4_destroy_inode(struct inode *inode)
  {
  	if (!list_empty(&(EXT4_I(inode)->i_orphan))) {
  		ext4_msg(inode->i_sb, KERN_ERR,
  			 "Inode %lu (%p): orphan list check failed!",
  			 inode->i_ino, EXT4_I(inode));
  		print_hex_dump(KERN_INFO, "", DUMP_PREFIX_ADDRESS, 16, 4,
  				EXT4_I(inode), sizeof(struct ext4_inode_info),
  				true);
  		dump_stack();
  	}
  	call_rcu(&inode->i_rcu, ext4_i_callback);
  }
  
  static void init_once(void *foo)
  {
  	struct ext4_inode_info *ei = (struct ext4_inode_info *) foo;
  
  	INIT_LIST_HEAD(&ei->i_orphan);
  #ifdef CONFIG_EXT4_FS_XATTR
  	init_rwsem(&ei->xattr_sem);
  #endif
  	init_rwsem(&ei->i_data_sem);
  	inode_init_once(&ei->vfs_inode);
  }
  
  static int init_inodecache(void)
  {
  	ext4_inode_cachep = kmem_cache_create("ext4_inode_cache",
  					     sizeof(struct ext4_inode_info),
  					     0, (SLAB_RECLAIM_ACCOUNT|
  						SLAB_MEM_SPREAD),
  					     init_once);
  	if (ext4_inode_cachep == NULL)
  		return -ENOMEM;
  	return 0;
  }
  
  static void destroy_inodecache(void)
  {
  	kmem_cache_destroy(ext4_inode_cachep);
  }
  
  void ext4_clear_inode(struct inode *inode)
  {
  	invalidate_inode_buffers(inode);
  	end_writeback(inode);
  	dquot_drop(inode);
  	ext4_discard_preallocations(inode);
  	if (EXT4_I(inode)->jinode) {
  		jbd2_journal_release_jbd_inode(EXT4_JOURNAL(inode),
  					       EXT4_I(inode)->jinode);
  		jbd2_free_inode(EXT4_I(inode)->jinode);
  		EXT4_I(inode)->jinode = NULL;
  	}
  }
  
  static inline void ext4_show_quota_options(struct seq_file *seq,
  					   struct super_block *sb)
  {
  #if defined(CONFIG_QUOTA)
  	struct ext4_sb_info *sbi = EXT4_SB(sb);
  
  	if (sbi->s_jquota_fmt) {
  		char *fmtname = "";
  
  		switch (sbi->s_jquota_fmt) {
  		case QFMT_VFS_OLD:
  			fmtname = "vfsold";
  			break;
  		case QFMT_VFS_V0:
  			fmtname = "vfsv0";
  			break;
  		case QFMT_VFS_V1:
  			fmtname = "vfsv1";
  			break;
  		}
  		seq_printf(seq, ",jqfmt=%s", fmtname);
  	}
  
  	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 (test_opt(sb, USRQUOTA))
  		seq_puts(seq, ",usrquota");
  
  	if (test_opt(sb, GRPQUOTA))
  		seq_puts(seq, ",grpquota");
  #endif
  }
  
  /*
   * Show an option if
   *  - it's set to a non-default value OR
   *  - if the per-sb default is different from the global default
   */
  static int ext4_show_options(struct seq_file *seq, struct vfsmount *vfs)
  {
  	int def_errors;
  	unsigned long def_mount_opts;
  	struct super_block *sb = vfs->mnt_sb;
  	struct ext4_sb_info *sbi = EXT4_SB(sb);
  	struct ext4_super_block *es = sbi->s_es;
  
  	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
  	def_errors     = le16_to_cpu(es->s_errors);
  
  	if (sbi->s_sb_block != 1)
  		seq_printf(seq, ",sb=%llu", sbi->s_sb_block);
  	if (test_opt(sb, MINIX_DF))
  		seq_puts(seq, ",minixdf");
  	if (test_opt(sb, GRPID) && !(def_mount_opts & EXT4_DEFM_BSDGROUPS))
  		seq_puts(seq, ",grpid");
  	if (!test_opt(sb, GRPID) && (def_mount_opts & EXT4_DEFM_BSDGROUPS))
  		seq_puts(seq, ",nogrpid");
  	if (sbi->s_resuid != EXT4_DEF_RESUID ||
  	    le16_to_cpu(es->s_def_resuid) != EXT4_DEF_RESUID) {
  		seq_printf(seq, ",resuid=%u", sbi->s_resuid);
  	}
  	if (sbi->s_resgid != EXT4_DEF_RESGID ||
  	    le16_to_cpu(es->s_def_resgid) != EXT4_DEF_RESGID) {
  		seq_printf(seq, ",resgid=%u", sbi->s_resgid);
  	}
  	if (test_opt(sb, ERRORS_RO)) {
  		if (def_errors == EXT4_ERRORS_PANIC ||
  		    def_errors == EXT4_ERRORS_CONTINUE) {
  			seq_puts(seq, ",errors=remount-ro");
  		}
  	}
  	if (test_opt(sb, ERRORS_CONT) && def_errors != EXT4_ERRORS_CONTINUE)
  		seq_puts(seq, ",errors=continue");
  	if (test_opt(sb, ERRORS_PANIC) && def_errors != EXT4_ERRORS_PANIC)
  		seq_puts(seq, ",errors=panic");
  	if (test_opt(sb, NO_UID32) && !(def_mount_opts & EXT4_DEFM_UID16))
  		seq_puts(seq, ",nouid32");
  	if (test_opt(sb, DEBUG) && !(def_mount_opts & EXT4_DEFM_DEBUG))
  		seq_puts(seq, ",debug");
  	if (test_opt(sb, OLDALLOC))
  		seq_puts(seq, ",oldalloc");
  #ifdef CONFIG_EXT4_FS_XATTR
  	if (test_opt(sb, XATTR_USER))
  		seq_puts(seq, ",user_xattr");
  	if (!test_opt(sb, XATTR_USER))
  		seq_puts(seq, ",nouser_xattr");
  #endif
  #ifdef CONFIG_EXT4_FS_POSIX_ACL
  	if (test_opt(sb, POSIX_ACL) && !(def_mount_opts & EXT4_DEFM_ACL))
  		seq_puts(seq, ",acl");
  	if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT4_DEFM_ACL))
  		seq_puts(seq, ",noacl");
  #endif
  	if (sbi->s_commit_interval != JBD2_DEFAULT_MAX_COMMIT_AGE*HZ) {
  		seq_printf(seq, ",commit=%u",
  			   (unsigned) (sbi->s_commit_interval / HZ));
  	}
  	if (sbi->s_min_batch_time != EXT4_DEF_MIN_BATCH_TIME) {
  		seq_printf(seq, ",min_batch_time=%u",
  			   (unsigned) sbi->s_min_batch_time);
  	}
  	if (sbi->s_max_batch_time != EXT4_DEF_MAX_BATCH_TIME) {
  		seq_printf(seq, ",max_batch_time=%u",
  			   (unsigned) sbi->s_min_batch_time);
  	}
  
  	/*
  	 * We're changing the default of barrier mount option, so
  	 * let's always display its mount state so it's clear what its
  	 * status is.
  	 */
  	seq_puts(seq, ",barrier=");
  	seq_puts(seq, test_opt(sb, BARRIER) ? "1" : "0");
  	if (test_opt(sb, JOURNAL_ASYNC_COMMIT))
  		seq_puts(seq, ",journal_async_commit");
  	else if (test_opt(sb, JOURNAL_CHECKSUM))
  		seq_puts(seq, ",journal_checksum");
  	if (test_opt(sb, I_VERSION))
  		seq_puts(seq, ",i_version");
  	if (!test_opt(sb, DELALLOC) &&
  	    !(def_mount_opts & EXT4_DEFM_NODELALLOC))
  		seq_puts(seq, ",nodelalloc");
  
  	if (!test_opt(sb, MBLK_IO_SUBMIT))
  		seq_puts(seq, ",nomblk_io_submit");
  	if (sbi->s_stripe)
  		seq_printf(seq, ",stripe=%lu", sbi->s_stripe);
  	/*
  	 * journal mode get enabled in different ways
  	 * So just print the value even if we didn't specify it
  	 */
  	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
  		seq_puts(seq, ",data=journal");
  	else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
  		seq_puts(seq, ",data=ordered");
  	else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)
  		seq_puts(seq, ",data=writeback");
  
  	if (sbi->s_inode_readahead_blks != EXT4_DEF_INODE_READAHEAD_BLKS)
  		seq_printf(seq, ",inode_readahead_blks=%u",
  			   sbi->s_inode_readahead_blks);
  
  	if (test_opt(sb, DATA_ERR_ABORT))
  		seq_puts(seq, ",data_err=abort");
  
  	if (test_opt(sb, NO_AUTO_DA_ALLOC))
  		seq_puts(seq, ",noauto_da_alloc");
  
  	if (test_opt(sb, DISCARD) && !(def_mount_opts & EXT4_DEFM_DISCARD))
  		seq_puts(seq, ",discard");
  
  	if (test_opt(sb, NOLOAD))
  		seq_puts(seq, ",norecovery");
  
  	if (test_opt(sb, DIOREAD_NOLOCK))
  		seq_puts(seq, ",dioread_nolock");
  
  	if (test_opt(sb, BLOCK_VALIDITY) &&
  	    !(def_mount_opts & EXT4_DEFM_BLOCK_VALIDITY))
  		seq_puts(seq, ",block_validity");
  
  	if (!test_opt(sb, INIT_INODE_TABLE))
  		seq_puts(seq, ",noinit_itable");
  	else if (sbi->s_li_wait_mult != EXT4_DEF_LI_WAIT_MULT)
  		seq_printf(seq, ",init_itable=%u",
  			   (unsigned) sbi->s_li_wait_mult);
  
  	ext4_show_quota_options(seq, sb);
  
  	return 0;
  }
  
  static struct inode *ext4_nfs_get_inode(struct super_block *sb,
  					u64 ino, u32 generation)
  {
  	struct inode *inode;
  
  	if (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)
  		return ERR_PTR(-ESTALE);
  	if (ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
  		return ERR_PTR(-ESTALE);
  
  	/* iget isn't really right if the inode is currently unallocated!!
  	 *
  	 * ext4_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 = ext4_iget(sb, ino);
  	if (IS_ERR(inode))
  		return ERR_CAST(inode);
  	if (generation && inode->i_generation != generation) {
  		iput(inode);
  		return ERR_PTR(-ESTALE);
  	}
  
  	return inode;
  }
  
  static struct dentry *ext4_fh_to_dentry(struct super_block *sb, struct fid *fid,
  					int fh_len, int fh_type)
  {
  	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
  				    ext4_nfs_get_inode);
  }
  
  static struct dentry *ext4_fh_to_parent(struct super_block *sb, struct fid *fid,
  					int fh_len, int fh_type)
  {
  	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
  				    ext4_nfs_get_inode);
  }
  
  /*
   * Try to release metadata pages (indirect blocks, directories) which are
   * mapped via the block device.  Since these pages could have journal heads
   * which would prevent try_to_free_buffers() from freeing them, we must use
   * jbd2 layer's try_to_free_buffers() function to release them.
   */
  static int bdev_try_to_free_page(struct super_block *sb, struct page *page,
  				 gfp_t wait)
  {
  	journal_t *journal = EXT4_SB(sb)->s_journal;
  
  	WARN_ON(PageChecked(page));
  	if (!page_has_buffers(page))
  		return 0;
  	if (journal)
  		return jbd2_journal_try_to_free_buffers(journal, page,
  							wait & ~__GFP_WAIT);
  	return try_to_free_buffers(page);
  }
  
  #ifdef CONFIG_QUOTA
  #define QTYPE2NAME(t) ((t) == USRQUOTA ? "user" : "group")
  #define QTYPE2MOPT(on, t) ((t) == USRQUOTA?((on)##USRJQUOTA):((on)##GRPJQUOTA))
  
  static int ext4_write_dquot(struct dquot *dquot);
  static int ext4_acquire_dquot(struct dquot *dquot);
  static int ext4_release_dquot(struct dquot *dquot);
  static int ext4_mark_dquot_dirty(struct dquot *dquot);
  static int ext4_write_info(struct super_block *sb, int type);
  static int ext4_quota_on(struct super_block *sb, int type, int format_id,
  			 struct path *path);
  static int ext4_quota_off(struct super_block *sb, int type);
  static int ext4_quota_on_mount(struct super_block *sb, int type);
  static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
  			       size_t len, loff_t off);
  static ssize_t ext4_quota_write(struct super_block *sb, int type,
  				const char *data, size_t len, loff_t off);
  
  static const struct dquot_operations ext4_quota_operations = {
  	.get_reserved_space = ext4_get_reserved_space,
  	.write_dquot	= ext4_write_dquot,
  	.acquire_dquot	= ext4_acquire_dquot,
  	.release_dquot	= ext4_release_dquot,
  	.mark_dirty	= ext4_mark_dquot_dirty,
  	.write_info	= ext4_write_info,
  	.alloc_dquot	= dquot_alloc,
  	.destroy_dquot	= dquot_destroy,
  };
  
  static const struct quotactl_ops ext4_qctl_operations = {
  	.quota_on	= ext4_quota_on,
  	.quota_off	= ext4_quota_off,
  	.quota_sync	= dquot_quota_sync,
  	.get_info	= dquot_get_dqinfo,
  	.set_info	= dquot_set_dqinfo,
  	.get_dqblk	= dquot_get_dqblk,
  	.set_dqblk	= dquot_set_dqblk
  };
  #endif
  
  static const struct super_operations ext4_sops = {
  	.alloc_inode	= ext4_alloc_inode,
  	.destroy_inode	= ext4_destroy_inode,
  	.write_inode	= ext4_write_inode,
  	.dirty_inode	= ext4_dirty_inode,
  	.drop_inode	= ext4_drop_inode,
  	.evict_inode	= ext4_evict_inode,
  	.put_super	= ext4_put_super,
  	.sync_fs	= ext4_sync_fs,
  	.freeze_fs	= ext4_freeze,
  	.unfreeze_fs	= ext4_unfreeze,
  	.statfs		= ext4_statfs,
  	.remount_fs	= ext4_remount,
  	.show_options	= ext4_show_options,
  #ifdef CONFIG_QUOTA
  	.quota_read	= ext4_quota_read,
  	.quota_write	= ext4_quota_write,
  #endif
  	.bdev_try_to_free_page = bdev_try_to_free_page,
  };
  
  static const struct super_operations ext4_nojournal_sops = {
  	.alloc_inode	= ext4_alloc_inode,
  	.destroy_inode	= ext4_destroy_inode,
  	.write_inode	= ext4_write_inode,
  	.dirty_inode	= ext4_dirty_inode,
  	.drop_inode	= ext4_drop_inode,
  	.evict_inode	= ext4_evict_inode,
  	.write_super	= ext4_write_super,
  	.put_super	= ext4_put_super,
  	.statfs		= ext4_statfs,
  	.remount_fs	= ext4_remount,
  	.show_options	= ext4_show_options,
  #ifdef CONFIG_QUOTA
  	.quota_read	= ext4_quota_read,
  	.quota_write	= ext4_quota_write,
  #endif
  	.bdev_try_to_free_page = bdev_try_to_free_page,
  };
  
  static const struct export_operations ext4_export_ops = {
  	.fh_to_dentry = ext4_fh_to_dentry,
  	.fh_to_parent = ext4_fh_to_parent,
  	.get_parent = ext4_get_parent,
  };
  
  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_debug, Opt_oldalloc, Opt_orlov,
  	Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
  	Opt_auto_da_alloc, Opt_noauto_da_alloc, Opt_noload, Opt_nobh, Opt_bh,
  	Opt_commit, Opt_min_batch_time, Opt_max_batch_time,
  	Opt_journal_update, Opt_journal_dev,
  	Opt_journal_checksum, Opt_journal_async_commit,
  	Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,
  	Opt_data_err_abort, Opt_data_err_ignore,
  	Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
  	Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_jqfmt_vfsv1, Opt_quota,
  	Opt_noquota, Opt_ignore, Opt_barrier, Opt_nobarrier, Opt_err,
  	Opt_resize, Opt_usrquota, Opt_grpquota, Opt_i_version,
  	Opt_stripe, Opt_delalloc, Opt_nodelalloc, Opt_mblk_io_submit,
  	Opt_nomblk_io_submit, Opt_block_validity, Opt_noblock_validity,
  	Opt_inode_readahead_blks, Opt_journal_ioprio,
  	Opt_dioread_nolock, Opt_dioread_lock,
  	Opt_discard, Opt_nodiscard, Opt_init_itable, Opt_noinit_itable,
  };
  
  static const 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_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_noload, "noload"},
  	{Opt_noload, "norecovery"},
  	{Opt_nobh, "nobh"},
  	{Opt_bh, "bh"},
  	{Opt_commit, "commit=%u"},
  	{Opt_min_batch_time, "min_batch_time=%u"},
  	{Opt_max_batch_time, "max_batch_time=%u"},
  	{Opt_journal_update, "journal=update"},
  	{Opt_journal_dev, "journal_dev=%u"},
  	{Opt_journal_checksum, "journal_checksum"},
  	{Opt_journal_async_commit, "journal_async_commit"},
  	{Opt_abort, "abort"},
  	{Opt_data_journal, "data=journal"},
  	{Opt_data_ordered, "data=ordered"},
  	{Opt_data_writeback, "data=writeback"},
  	{Opt_data_err_abort, "data_err=abort"},
  	{Opt_data_err_ignore, "data_err=ignore"},
  	{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_jqfmt_vfsv1, "jqfmt=vfsv1"},
  	{Opt_grpquota, "grpquota"},
  	{Opt_noquota, "noquota"},
  	{Opt_quota, "quota"},
  	{Opt_usrquota, "usrquota"},
  	{Opt_barrier, "barrier=%u"},
  	{Opt_barrier, "barrier"},
  	{Opt_nobarrier, "nobarrier"},
  	{Opt_i_version, "i_version"},
  	{Opt_stripe, "stripe=%u"},
  	{Opt_resize, "resize"},
  	{Opt_delalloc, "delalloc"},
  	{Opt_nodelalloc, "nodelalloc"},
  	{Opt_mblk_io_submit, "mblk_io_submit"},
  	{Opt_nomblk_io_submit, "nomblk_io_submit"},
  	{Opt_block_validity, "block_validity"},
  	{Opt_noblock_validity, "noblock_validity"},
  	{Opt_inode_readahead_blks, "inode_readahead_blks=%u"},
  	{Opt_journal_ioprio, "journal_ioprio=%u"},
  	{Opt_auto_da_alloc, "auto_da_alloc=%u"},
  	{Opt_auto_da_alloc, "auto_da_alloc"},
  	{Opt_noauto_da_alloc, "noauto_da_alloc"},
  	{Opt_dioread_nolock, "dioread_nolock"},
  	{Opt_dioread_lock, "dioread_lock"},
  	{Opt_discard, "discard"},
  	{Opt_nodiscard, "nodiscard"},
  	{Opt_init_itable, "init_itable=%u"},
  	{Opt_init_itable, "init_itable"},
  	{Opt_noinit_itable, "noinit_itable"},
  	{Opt_err, NULL},
  };
  
  static ext4_fsblk_t get_sb_block(void **data)
  {
  	ext4_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 ext4 */
  	sb_block = simple_strtoul(options, &options, 0);
  	if (*options && *options != ',') {
  		printk(KERN_ERR "EXT4-fs: Invalid sb specification: %s\n",
  		       (char *) *data);
  		return 1;
  	}
  	if (*options == ',')
  		options++;
  	*data = (void *) options;
  
  	return sb_block;
  }
  
  #define DEFAULT_JOURNAL_IOPRIO (IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 3))
  static char deprecated_msg[] = "Mount option \"%s\" will be removed by %s\n"
  	"Contact linux-ext4@vger.kernel.org if you think we should keep it.\n";
  
  #ifdef CONFIG_QUOTA
  static int set_qf_name(struct super_block *sb, int qtype, substring_t *args)
  {
  	struct ext4_sb_info *sbi = EXT4_SB(sb);
  	char *qname;
  
  	if (sb_any_quota_loaded(sb) &&
  		!sbi->s_qf_names[qtype]) {
  		ext4_msg(sb, KERN_ERR,
  			"Cannot change journaled "
  			"quota options when quota turned on");
  		return 0;
  	}
  	qname = match_strdup(args);
  	if (!qname) {
  		ext4_msg(sb, KERN_ERR,
  			"Not enough memory for storing quotafile name");
  		return 0;
  	}
  	if (sbi->s_qf_names[qtype] &&
  		strcmp(sbi->s_qf_names[qtype], qname)) {
  		ext4_msg(sb, KERN_ERR,
  			"%s quota file already specified", QTYPE2NAME(qtype));
  		kfree(qname);
  		return 0;
  	}
  	sbi->s_qf_names[qtype] = qname;
  	if (strchr(sbi->s_qf_names[qtype], '/')) {
  		ext4_msg(sb, KERN_ERR,
  			"quotafile must be on filesystem root");
  		kfree(sbi->s_qf_names[qtype]);
  		sbi->s_qf_names[qtype] = NULL;
  		return 0;
  	}
  	set_opt(sb, QUOTA);
  	return 1;
  }
  
  static int clear_qf_name(struct super_block *sb, int qtype)
  {
  
  	struct ext4_sb_info *sbi = EXT4_SB(sb);
  
  	if (sb_any_quota_loaded(sb) &&
  		sbi->s_qf_names[qtype]) {
  		ext4_msg(sb, KERN_ERR, "Cannot change journaled quota options"
  			" when quota turned on");
  		return 0;
  	}
  	/*
  	 * The space will be released later when all options are confirmed
  	 * to be correct
  	 */
  	sbi->s_qf_names[qtype] = NULL;
  	return 1;
  }
  #endif
  
  static int parse_options(char *options, struct super_block *sb,
  			 unsigned long *journal_devnum,
  			 unsigned int *journal_ioprio,
  			 ext4_fsblk_t *n_blocks_count, int is_remount)
  {
  	struct ext4_sb_info *sbi = EXT4_SB(sb);
  	char *p;
  	substring_t args[MAX_OPT_ARGS];
  	int data_opt = 0;
  	int option;
  #ifdef CONFIG_QUOTA
  	int qfmt;
  #endif
  
  	if (!options)
  		return 1;
  
  	while ((p = strsep(&options, ",")) != NULL) {
  		int token;
  		if (!*p)
  			continue;
  
  		/*
  		 * Initialize args struct so we know whether arg was
  		 * found; some options take optional arguments.
  		 */
  		args[0].to = args[0].from = NULL;
  		token = match_token(p, tokens, args);
  		switch (token) {
  		case Opt_bsd_df:
  			ext4_msg(sb, KERN_WARNING, deprecated_msg, p, "2.6.38");
  			clear_opt(sb, MINIX_DF);
  			break;
  		case Opt_minix_df:
  			ext4_msg(sb, KERN_WARNING, deprecated_msg, p, "2.6.38");
  			set_opt(sb, MINIX_DF);
  
  			break;
  		case Opt_grpid:
  			ext4_msg(sb, KERN_WARNING, deprecated_msg, p, "2.6.38");
  			set_opt(sb, GRPID);
  
  			break;
  		case Opt_nogrpid:
  			ext4_msg(sb, KERN_WARNING, deprecated_msg, p, "2.6.38");
  			clear_opt(sb, 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(sb, ERRORS_CONT);
  			clear_opt(sb, ERRORS_RO);
  			set_opt(sb, ERRORS_PANIC);
  			break;
  		case Opt_err_ro:
  			clear_opt(sb, ERRORS_CONT);
  			clear_opt(sb, ERRORS_PANIC);
  			set_opt(sb, ERRORS_RO);
  			break;
  		case Opt_err_cont:
  			clear_opt(sb, ERRORS_RO);
  			clear_opt(sb, ERRORS_PANIC);
  			set_opt(sb, ERRORS_CONT);
  			break;
  		case Opt_nouid32:
  			set_opt(sb, NO_UID32);
  			break;
  		case Opt_debug:
  			set_opt(sb, DEBUG);
  			break;
  		case Opt_oldalloc:
  			set_opt(sb, OLDALLOC);
  			break;
  		case Opt_orlov:
  			clear_opt(sb, OLDALLOC);
  			break;
  #ifdef CONFIG_EXT4_FS_XATTR
  		case Opt_user_xattr:
  			set_opt(sb, XATTR_USER);
  			break;
  		case Opt_nouser_xattr:
  			clear_opt(sb, XATTR_USER);
  			break;
  #else
  		case Opt_user_xattr:
  		case Opt_nouser_xattr:
  			ext4_msg(sb, KERN_ERR, "(no)user_xattr options not supported");
  			break;
  #endif
  #ifdef CONFIG_EXT4_FS_POSIX_ACL
  		case Opt_acl:
  			set_opt(sb, POSIX_ACL);
  			break;
  		case Opt_noacl:
  			clear_opt(sb, POSIX_ACL);
  			break;
  #else
  		case Opt_acl:
  		case Opt_noacl:
  			ext4_msg(sb, KERN_ERR, "(no)acl options not supported");
  			break;
  #endif
  		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) {
  				ext4_msg(sb, KERN_ERR,
  					 "Cannot specify journal on remount");
  				return 0;
  			}
  			set_opt(sb, UPDATE_JOURNAL);
  			break;
  		case Opt_journal_dev:
  			if (is_remount) {
  				ext4_msg(sb, KERN_ERR,
  					"Cannot specify journal on remount");
  				return 0;
  			}
  			if (match_int(&args[0], &option))
  				return 0;
  			*journal_devnum = option;
  			break;
  		case Opt_journal_checksum:
  			set_opt(sb, JOURNAL_CHECKSUM);
  			break;
  		case Opt_journal_async_commit:
  			set_opt(sb, JOURNAL_ASYNC_COMMIT);
  			set_opt(sb, JOURNAL_CHECKSUM);
  			break;
  		case Opt_noload:
  			set_opt(sb, NOLOAD);
  			break;
  		case Opt_commit:
  			if (match_int(&args[0], &option))
  				return 0;
  			if (option < 0)
  				return 0;
  			if (option == 0)
  				option = JBD2_DEFAULT_MAX_COMMIT_AGE;
  			sbi->s_commit_interval = HZ * option;
  			break;
  		case Opt_max_batch_time:
  			if (match_int(&args[0], &option))
  				return 0;
  			if (option < 0)
  				return 0;
  			if (option == 0)
  				option = EXT4_DEF_MAX_BATCH_TIME;
  			sbi->s_max_batch_time = option;
  			break;
  		case Opt_min_batch_time:
  			if (match_int(&args[0], &option))
  				return 0;
  			if (option < 0)
  				return 0;
  			sbi->s_min_batch_time = option;
  			break;
  		case Opt_data_journal:
  			data_opt = EXT4_MOUNT_JOURNAL_DATA;
  			goto datacheck;
  		case Opt_data_ordered:
  			data_opt = EXT4_MOUNT_ORDERED_DATA;
  			goto datacheck;
  		case Opt_data_writeback:
  			data_opt = EXT4_MOUNT_WRITEBACK_DATA;
  		datacheck:
  			if (is_remount) {
  				if (test_opt(sb, DATA_FLAGS) != data_opt) {
  					ext4_msg(sb, KERN_ERR,
  						"Cannot change data mode on remount");
  					return 0;
  				}
  			} else {
  				clear_opt(sb, DATA_FLAGS);
  				sbi->s_mount_opt |= data_opt;
  			}
  			break;
  		case Opt_data_err_abort:
  			set_opt(sb, DATA_ERR_ABORT);
  			break;
  		case Opt_data_err_ignore:
  			clear_opt(sb, DATA_ERR_ABORT);
  			break;
  #ifdef CONFIG_QUOTA
  		case Opt_usrjquota:
  			if (!set_qf_name(sb, USRQUOTA, &args[0]))
  				return 0;
  			break;
  		case Opt_grpjquota:
  			if (!set_qf_name(sb, GRPQUOTA, &args[0]))
  				return 0;
  			break;
  		case Opt_offusrjquota:
  			if (!clear_qf_name(sb, USRQUOTA))
  				return 0;
  			break;
  		case Opt_offgrpjquota:
  			if (!clear_qf_name(sb, GRPQUOTA))
  				return 0;
  			break;
  
  		case Opt_jqfmt_vfsold:
  			qfmt = QFMT_VFS_OLD;
  			goto set_qf_format;
  		case Opt_jqfmt_vfsv0:
  			qfmt = QFMT_VFS_V0;
  			goto set_qf_format;
  		case Opt_jqfmt_vfsv1:
  			qfmt = QFMT_VFS_V1;
  set_qf_format:
  			if (sb_any_quota_loaded(sb) &&
  			    sbi->s_jquota_fmt != qfmt) {
  				ext4_msg(sb, KERN_ERR, "Cannot change "
  					"journaled quota options when "
  					"quota turned on");
  				return 0;
  			}
  			sbi->s_jquota_fmt = qfmt;
  			break;
  		case Opt_quota:
  		case Opt_usrquota:
  			set_opt(sb, QUOTA);
  			set_opt(sb, USRQUOTA);
  			break;
  		case Opt_grpquota:
  			set_opt(sb, QUOTA);
  			set_opt(sb, GRPQUOTA);
  			break;
  		case Opt_noquota:
  			if (sb_any_quota_loaded(sb)) {
  				ext4_msg(sb, KERN_ERR, "Cannot change quota "
  					"options when quota turned on");
  				return 0;
  			}
  			clear_opt(sb, QUOTA);
  			clear_opt(sb, USRQUOTA);
  			clear_opt(sb, GRPQUOTA);
  			break;
  #else
  		case Opt_quota:
  		case Opt_usrquota:
  		case Opt_grpquota:
  			ext4_msg(sb, KERN_ERR,
  				"quota options not supported");
  			break;
  		case Opt_usrjquota:
  		case Opt_grpjquota:
  		case Opt_offusrjquota:
  		case Opt_offgrpjquota:
  		case Opt_jqfmt_vfsold:
  		case Opt_jqfmt_vfsv0:
  		case Opt_jqfmt_vfsv1:
  			ext4_msg(sb, KERN_ERR,
  				"journaled quota options not supported");
  			break;
  		case Opt_noquota:
  			break;
  #endif
  		case Opt_abort:
  			sbi->s_mount_flags |= EXT4_MF_FS_ABORTED;
  			break;
  		case Opt_nobarrier:
  			clear_opt(sb, BARRIER);
  			break;
  		case Opt_barrier:
  			if (args[0].from) {
  				if (match_int(&args[0], &option))
  					return 0;
  			} else
  				option = 1;	/* No argument, default to 1 */
  			if (option)
  				set_opt(sb, BARRIER);
  			else
  				clear_opt(sb, BARRIER);
  			break;
  		case Opt_ignore:
  			break;
  		case Opt_resize:
  			if (!is_remount) {
  				ext4_msg(sb, KERN_ERR,
  					"resize option only available "
  					"for remount");
  				return 0;
  			}
  			if (match_int(&args[0], &option) != 0)
  				return 0;
  			*n_blocks_count = option;
  			break;
  		case Opt_nobh:
  			ext4_msg(sb, KERN_WARNING,
  				 "Ignoring deprecated nobh option");
  			break;
  		case Opt_bh:
  			ext4_msg(sb, KERN_WARNING,
  				 "Ignoring deprecated bh option");
  			break;
  		case Opt_i_version:
  			set_opt(sb, I_VERSION);
  			sb->s_flags |= MS_I_VERSION;
  			break;
  		case Opt_nodelalloc:
  			clear_opt(sb, DELALLOC);
  			break;
  		case Opt_mblk_io_submit:
  			set_opt(sb, MBLK_IO_SUBMIT);
  			break;
  		case Opt_nomblk_io_submit:
  			clear_opt(sb, MBLK_IO_SUBMIT);
  			break;
  		case Opt_stripe:
  			if (match_int(&args[0], &option))
  				return 0;
  			if (option < 0)
  				return 0;
  			sbi->s_stripe = option;
  			break;
  		case Opt_delalloc:
  			set_opt(sb, DELALLOC);
  			break;
  		case Opt_block_validity:
  			set_opt(sb, BLOCK_VALIDITY);
  			break;
  		case Opt_noblock_validity:
  			clear_opt(sb, BLOCK_VALIDITY);
  			break;
  		case Opt_inode_readahead_blks:
  			if (match_int(&args[0], &option))
  				return 0;
  			if (option < 0 || option > (1 << 30))
  				return 0;
  			if (option && !is_power_of_2(option)) {
  				ext4_msg(sb, KERN_ERR,
  					 "EXT4-fs: inode_readahead_blks"
  					 " must be a power of 2");
  				return 0;
  			}
  			sbi->s_inode_readahead_blks = option;
  			break;
  		case Opt_journal_ioprio:
  			if (match_int(&args[0], &option))
  				return 0;
  			if (option < 0 || option > 7)
  				break;
  			*journal_ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE,
  							    option);
  			break;
  		case Opt_noauto_da_alloc:
  			set_opt(sb, NO_AUTO_DA_ALLOC);
  			break;
  		case Opt_auto_da_alloc:
  			if (args[0].from) {
  				if (match_int(&args[0], &option))
  					return 0;
  			} else
  				option = 1;	/* No argument, default to 1 */
  			if (option)
  				clear_opt(sb, NO_AUTO_DA_ALLOC);
  			else
  				set_opt(sb,NO_AUTO_DA_ALLOC);
  			break;
  		case Opt_discard:
  			set_opt(sb, DISCARD);
  			break;
  		case Opt_nodiscard:
  			clear_opt(sb, DISCARD);
  			break;
  		case Opt_dioread_nolock:
  			set_opt(sb, DIOREAD_NOLOCK);
  			break;
  		case Opt_dioread_lock:
  			clear_opt(sb, DIOREAD_NOLOCK);
  			break;
  		case Opt_init_itable:
  			set_opt(sb, INIT_INODE_TABLE);
  			if (args[0].from) {
  				if (match_int(&args[0], &option))
  					return 0;
  			} else
  				option = EXT4_DEF_LI_WAIT_MULT;
  			if (option < 0)
  				return 0;
  			sbi->s_li_wait_mult = option;
  			break;
  		case Opt_noinit_itable:
  			clear_opt(sb, INIT_INODE_TABLE);
  			break;
  		default:
  			ext4_msg(sb, KERN_ERR,
  			       "Unrecognized mount option \"%s\" "
  			       "or missing value", p);
  			return 0;
  		}
  	}
  #ifdef CONFIG_QUOTA
  	if (sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
  		if (test_opt(sb, USRQUOTA) && sbi->s_qf_names[USRQUOTA])
  			clear_opt(sb, USRQUOTA);
  
  		if (test_opt(sb, GRPQUOTA) && sbi->s_qf_names[GRPQUOTA])
  			clear_opt(sb, GRPQUOTA);
  
  		if (test_opt(sb, GRPQUOTA) || test_opt(sb, USRQUOTA)) {
  			ext4_msg(sb, KERN_ERR, "old and new quota "
  					"format mixing");
  			return 0;
  		}
  
  		if (!sbi->s_jquota_fmt) {
  			ext4_msg(sb, KERN_ERR, "journaled quota format "
  					"not specified");
  			return 0;
  		}
  	} else {
  		if (sbi->s_jquota_fmt) {
  			ext4_msg(sb, KERN_ERR, "journaled quota format "
  					"specified with no journaling "
  					"enabled");
  			return 0;
  		}
  	}
  #endif
  	return 1;
  }
  
  static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
  			    int read_only)
  {
  	struct ext4_sb_info *sbi = EXT4_SB(sb);
  	int res = 0;
  
  	if (le32_to_cpu(es->s_rev_level) > EXT4_MAX_SUPP_REV) {
  		ext4_msg(sb, KERN_ERR, "revision level too high, "
  			 "forcing read-only mode");
  		res = MS_RDONLY;
  	}
  	if (read_only)
  		return res;
  	if (!(sbi->s_mount_state & EXT4_VALID_FS))
  		ext4_msg(sb, KERN_WARNING, "warning: mounting unchecked fs, "
  			 "running e2fsck is recommended");
  	else if ((sbi->s_mount_state & EXT4_ERROR_FS))
  		ext4_msg(sb, KERN_WARNING,
  			 "warning: mounting fs with errors, "
  			 "running e2fsck is recommended");
  	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))
  		ext4_msg(sb, KERN_WARNING,
  			 "warning: maximal mount count reached, "
  			 "running e2fsck is recommended");
  	else if (le32_to_cpu(es->s_checkinterval) &&
  		(le32_to_cpu(es->s_lastcheck) +
  			le32_to_cpu(es->s_checkinterval) <= get_seconds()))
  		ext4_msg(sb, KERN_WARNING,
  			 "warning: checktime reached, "
  			 "running e2fsck is recommended");
  	if (!sbi->s_journal)
  		es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
  	if (!(__s16) le16_to_cpu(es->s_max_mnt_count))
  		es->s_max_mnt_count = cpu_to_le16(EXT4_DFL_MAX_MNT_COUNT);
  	le16_add_cpu(&es->s_mnt_count, 1);
  	es->s_mtime = cpu_to_le32(get_seconds());
  	ext4_update_dynamic_rev(sb);
  	if (sbi->s_journal)
  		EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
  
  	ext4_commit_super(sb, 1);
  	if (test_opt(sb, DEBUG))
  		printk(KERN_INFO "[EXT4 FS bs=%lu, gc=%u, "
  				"bpg=%lu, ipg=%lu, mo=%04x, mo2=%04x]\n",
  			sb->s_blocksize,
  			sbi->s_groups_count,
  			EXT4_BLOCKS_PER_GROUP(sb),
  			EXT4_INODES_PER_GROUP(sb),
  			sbi->s_mount_opt, sbi->s_mount_opt2);
  
  	cleancache_init_fs(sb);
  	return res;
  }
  
  static int ext4_fill_flex_info(struct super_block *sb)
  {
  	struct ext4_sb_info *sbi = EXT4_SB(sb);
  	struct ext4_group_desc *gdp = NULL;
  	ext4_group_t flex_group_count;
  	ext4_group_t flex_group;
  	unsigned int groups_per_flex = 0;
  	size_t size;
  	int i;
  
  	sbi->s_log_groups_per_flex = sbi->s_es->s_log_groups_per_flex;
  	if (sbi->s_log_groups_per_flex < 1 || sbi->s_log_groups_per_flex > 31) {
  		sbi->s_log_groups_per_flex = 0;
  		return 1;
  	}
  	groups_per_flex = 1 << sbi->s_log_groups_per_flex;
  
  	/* We allocate both existing and potentially added groups */
  	flex_group_count = ((sbi->s_groups_count + groups_per_flex - 1) +
  			((le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) + 1) <<
  			      EXT4_DESC_PER_BLOCK_BITS(sb))) / groups_per_flex;
  	size = flex_group_count * sizeof(struct flex_groups);
  	sbi->s_flex_groups = kzalloc(size, GFP_KERNEL);
  	if (sbi->s_flex_groups == NULL) {
  		sbi->s_flex_groups = vzalloc(size);
  		if (sbi->s_flex_groups == NULL) {
  			ext4_msg(sb, KERN_ERR,
  				 "not enough memory for %u flex groups",
  				 flex_group_count);
  			goto failed;
  		}
  	}
  
  	for (i = 0; i < sbi->s_groups_count; i++) {
  		gdp = ext4_get_group_desc(sb, i, NULL);
  
  		flex_group = ext4_flex_group(sbi, i);
  		atomic_add(ext4_free_inodes_count(sb, gdp),
  			   &sbi->s_flex_groups[flex_group].free_inodes);
  		atomic64_add(ext4_free_blks_count(sb, gdp),
  			     &sbi->s_flex_groups[flex_group].free_blocks);
  		atomic_add(ext4_used_dirs_count(sb, gdp),
  			   &sbi->s_flex_groups[flex_group].used_dirs);
  	}
  
  	return 1;
  failed:
  	return 0;
  }
  
  __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group,
  			    struct ext4_group_desc *gdp)
  {
  	__u16 crc = 0;
  
  	if (sbi->s_es->s_feature_ro_compat &
  	    cpu_to_le32(EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
  		int offset = offsetof(struct ext4_group_desc, bg_checksum);
  		__le32 le_group = cpu_to_le32(block_group);
  
  		crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid));
  		crc = crc16(crc, (__u8 *)&le_group, sizeof(le_group));
  		crc = crc16(crc, (__u8 *)gdp, offset);
  		offset += sizeof(gdp->bg_checksum); /* skip checksum */
  		/* for checksum of struct ext4_group_desc do the rest...*/
  		if ((sbi->s_es->s_feature_incompat &
  		     cpu_to_le32(EXT4_FEATURE_INCOMPAT_64BIT)) &&
  		    offset < le16_to_cpu(sbi->s_es->s_desc_size))
  			crc = crc16(crc, (__u8 *)gdp + offset,
  				    le16_to_cpu(sbi->s_es->s_desc_size) -
  					offset);
  	}
  
  	return cpu_to_le16(crc);
  }
  
  int ext4_group_desc_csum_verify(struct ext4_sb_info *sbi, __u32 block_group,
  				struct ext4_group_desc *gdp)
  {
  	if ((sbi->s_es->s_feature_ro_compat &
  	     cpu_to_le32(EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) &&
  	    (gdp->bg_checksum != ext4_group_desc_csum(sbi, block_group, gdp)))
  		return 0;
  
  	return 1;
  }
  
  /* Called at mount-time, super-block is locked */
  static int ext4_check_descriptors(struct super_block *sb,
  				  ext4_group_t *first_not_zeroed)
  {
  	struct ext4_sb_info *sbi = EXT4_SB(sb);
  	ext4_fsblk_t first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
  	ext4_fsblk_t last_block;
  	ext4_fsblk_t block_bitmap;
  	ext4_fsblk_t inode_bitmap;
  	ext4_fsblk_t inode_table;
  	int flexbg_flag = 0;
  	ext4_group_t i, grp = sbi->s_groups_count;
  
  	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
  		flexbg_flag = 1;
  
  	ext4_debug("Checking group descriptors");
  
  	for (i = 0; i < sbi->s_groups_count; i++) {
  		struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
  
  		if (i == sbi->s_groups_count - 1 || flexbg_flag)
  			last_block = ext4_blocks_count(sbi->s_es) - 1;
  		else
  			last_block = first_block +
  				(EXT4_BLOCKS_PER_GROUP(sb) - 1);
  
  		if ((grp == sbi->s_groups_count) &&
  		   !(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
  			grp = i;
  
  		block_bitmap = ext4_block_bitmap(sb, gdp);
  		if (block_bitmap < first_block || block_bitmap > last_block) {
  			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
  			       "Block bitmap for group %u not in group "
  			       "(block %llu)!", i, block_bitmap);
  			return 0;
  		}
  		inode_bitmap = ext4_inode_bitmap(sb, gdp);
  		if (inode_bitmap < first_block || inode_bitmap > last_block) {
  			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
  			       "Inode bitmap for group %u not in group "
  			       "(block %llu)!", i, inode_bitmap);
  			return 0;
  		}
  		inode_table = ext4_inode_table(sb, gdp);
  		if (inode_table < first_block ||
  		    inode_table + sbi->s_itb_per_group - 1 > last_block) {
  			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
  			       "Inode table for group %u not in group "
  			       "(block %llu)!", i, inode_table);
  			return 0;
  		}
  		ext4_lock_group(sb, i);
  		if (!ext4_group_desc_csum_verify(sbi, i, gdp)) {
  			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
  				 "Checksum for group %u failed (%u!=%u)",
  				 i, le16_to_cpu(ext4_group_desc_csum(sbi, i,
  				     gdp)), le16_to_cpu(gdp->bg_checksum));
  			if (!(sb->s_flags & MS_RDONLY)) {
  				ext4_unlock_group(sb, i);
  				return 0;
  			}
  		}
  		ext4_unlock_group(sb, i);
  		if (!flexbg_flag)
  			first_block += EXT4_BLOCKS_PER_GROUP(sb);
  	}
  	if (NULL != first_not_zeroed)
  		*first_not_zeroed = grp;
  
  	ext4_free_blocks_count_set(sbi->s_es, ext4_count_free_blocks(sb));
  	sbi->s_es->s_free_inodes_count =cpu_to_le32(ext4_count_free_inodes(sb));
  	return 1;
  }
  
  /* ext4_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
   * ext4_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 ext4_orphan_cleanup(struct super_block *sb,
  				struct ext4_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 (bdev_read_only(sb->s_bdev)) {
  		ext4_msg(sb, KERN_ERR, "write access "
  			"unavailable, skipping orphan cleanup");
  		return;
  	}
  
  	/* Check if feature set would not allow a r/w mount */
  	if (!ext4_feature_set_ok(sb, 0)) {
  		ext4_msg(sb, KERN_INFO, "Skipping orphan cleanup due to "
  			 "unknown ROCOMPAT features");
  		return;
  	}
  
  	if (EXT4_SB(sb)->s_mount_state & EXT4_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) {
  		ext4_msg(sb, KERN_INFO, "orphan cleanup on readonly fs");
  		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 (EXT4_SB(sb)->s_qf_names[i]) {
  			int ret = ext4_quota_on_mount(sb, i);
  			if (ret < 0)
  				ext4_msg(sb, KERN_ERR,
  					"Cannot turn on journaled "
  					"quota: error %d", ret);
  		}
  	}
  #endif
  
  	while (es->s_last_orphan) {
  		struct inode *inode;
  
  		inode = ext4_orphan_get(sb, le32_to_cpu(es->s_last_orphan));
  		if (IS_ERR(inode)) {
  			es->s_last_orphan = 0;
  			break;
  		}
  
  		list_add(&EXT4_I(inode)->i_orphan, &EXT4_SB(sb)->s_orphan);
  		dquot_initialize(inode);
  		if (inode->i_nlink) {
  			ext4_msg(sb, KERN_DEBUG,
  				"%s: truncating inode %lu to %lld bytes",
  				__func__, inode->i_ino, inode->i_size);
  			jbd_debug(2, "truncating inode %lu to %lld bytes\n",
  				  inode->i_ino, inode->i_size);
  			mutex_lock(&inode->i_mutex);
  			ext4_truncate(inode);
  			mutex_unlock(&inode->i_mutex);
  			nr_truncates++;
  		} else {
  			ext4_msg(sb, KERN_DEBUG,
  				"%s: deleting unreferenced inode %lu",
  				__func__, inode->i_ino);
  			jbd_debug(2, "deleting unreferenced inode %lu\n",
  				  inode->i_ino);
  			nr_orphans++;
  		}
  		iput(inode);  /* The delete magic happens here! */
  	}
  
  #define PLURAL(x) (x), ((x) == 1) ? "" : "s"
  
  	if (nr_orphans)
  		ext4_msg(sb, KERN_INFO, "%d orphan inode%s deleted",
  		       PLURAL(nr_orphans));
  	if (nr_truncates)
  		ext4_msg(sb, KERN_INFO, "%d truncate%s cleaned up",
  		       PLURAL(nr_truncates));
  #ifdef CONFIG_QUOTA
  	/* Turn quotas off */
  	for (i = 0; i < MAXQUOTAS; i++) {
  		if (sb_dqopt(sb)->files[i])
  			dquot_quota_off(sb, i);
  	}
  #endif
  	sb->s_flags = s_flags; /* Restore MS_RDONLY status */
  }
  
  /*
   * Maximal extent format file size.
   * Resulting logical blkno at s_maxbytes must fit in our on-disk
   * extent format containers, within a sector_t, and within i_blocks
   * in the vfs.  ext4 inode has 48 bits of i_block in fsblock units,
   * so that won't be a limiting factor.
   *
   * However there is other limiting factor. We do store extents in the form
   * of starting block and length, hence the resulting length of the extent
   * covering maximum file size must fit into on-disk format containers as
   * well. Given that length is always by 1 unit bigger than max unit (because
   * we count 0 as well) we have to lower the s_maxbytes by one fs block.
   *
   * Note, this does *not* consider any metadata overhead for vfs i_blocks.
   */
  static loff_t ext4_max_size(int blkbits, int has_huge_files)
  {
  	loff_t res;
  	loff_t upper_limit = MAX_LFS_FILESIZE;
  
  	/* small i_blocks in vfs inode? */
  	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
  		/*
  		 * CONFIG_LBDAF is not enabled implies the inode
  		 * i_block represent total blocks in 512 bytes
  		 * 32 == size of vfs inode i_blocks * 8
  		 */
  		upper_limit = (1LL << 32) - 1;
  
  		/* total blocks in file system block size */
  		upper_limit >>= (blkbits - 9);
  		upper_limit <<= blkbits;
  	}
  
  	/*
  	 * 32-bit extent-start container, ee_block. We lower the maxbytes
  	 * by one fs block, so ee_len can cover the extent of maximum file
  	 * size
  	 */
  	res = (1LL << 32) - 1;
  	res <<= blkbits;
  
  	/* Sanity check against vm- & vfs- imposed limits */
  	if (res > upper_limit)
  		res = upper_limit;
  
  	return res;
  }
  
  /*
   * Maximal bitmap file size.  There is a direct, and {,double-,triple-}indirect
   * block limit, and also a limit of (2^48 - 1) 512-byte sectors in i_blocks.
   * We need to be 1 filesystem block less than the 2^48 sector limit.
   */
  static loff_t ext4_max_bitmap_size(int bits, int has_huge_files)
  {
  	loff_t res = EXT4_NDIR_BLOCKS;
  	int meta_blocks;
  	loff_t upper_limit;
  	/* This is calculated to be the largest file size for a dense, block
  	 * mapped file such that the file's total number of 512-byte sectors,
  	 * including data and all indirect blocks, does not exceed (2^48 - 1).
  	 *
  	 * __u32 i_blocks_lo and _u16 i_blocks_high represent the total
  	 * number of 512-byte sectors of the file.
  	 */
  
  	if (!has_huge_files || sizeof(blkcnt_t) < sizeof(u64)) {
  		/*
  		 * !has_huge_files or CONFIG_LBDAF not enabled implies that
  		 * the inode i_block field represents total file blocks in
  		 * 2^32 512-byte sectors == size of vfs inode i_blocks * 8
  		 */
  		upper_limit = (1LL << 32) - 1;
  
  		/* total blocks in file system block size */
  		upper_limit >>= (bits - 9);
  
  	} else {
  		/*
  		 * We use 48 bit ext4_inode i_blocks
  		 * With EXT4_HUGE_FILE_FL set the i_blocks
  		 * represent total number of blocks in
  		 * file system block size
  		 */
  		upper_limit = (1LL << 48) - 1;
  
  	}
  
  	/* indirect blocks */
  	meta_blocks = 1;
  	/* double indirect blocks */
  	meta_blocks += 1 + (1LL << (bits-2));
  	/* tripple indirect blocks */
  	meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
  
  	upper_limit -= meta_blocks;
  	upper_limit <<= bits;
  
  	res += 1LL << (bits-2);
  	res += 1LL << (2*(bits-2));
  	res += 1LL << (3*(bits-2));
  	res <<= bits;
  	if (res > upper_limit)
  		res = upper_limit;
  
  	if (res > MAX_LFS_FILESIZE)
  		res = MAX_LFS_FILESIZE;
  
  	return res;
  }
  
  static ext4_fsblk_t descriptor_loc(struct super_block *sb,
  				   ext4_fsblk_t logical_sb_block, int nr)
  {
  	struct ext4_sb_info *sbi = EXT4_SB(sb);
  	ext4_group_t bg, first_meta_bg;
  	int has_super = 0;
  
  	first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
  
  	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) ||
  	    nr < first_meta_bg)
  		return logical_sb_block + nr + 1;
  	bg = sbi->s_desc_per_block * nr;
  	if (ext4_bg_has_super(sb, bg))
  		has_super = 1;
  
  	return (has_super + ext4_group_first_block_no(sb, bg));
  }
  
  /**
   * ext4_get_stripe_size: Get the stripe size.
   * @sbi: In memory super block info
   *
   * If we have specified it via mount option, then
   * use the mount option value. If the value specified at mount time is
   * greater than the blocks per group use the super block value.
   * If the super block value is greater than blocks per group return 0.
   * Allocator needs it be less than blocks per group.
   *
   */
  static unsigned long ext4_get_stripe_size(struct ext4_sb_info *sbi)
  {
  	unsigned long stride = le16_to_cpu(sbi->s_es->s_raid_stride);
  	unsigned long stripe_width =
  			le32_to_cpu(sbi->s_es->s_raid_stripe_width);
  
  	if (sbi->s_stripe && sbi->s_stripe <= sbi->s_blocks_per_group)
  		return sbi->s_stripe;
  
  	if (stripe_width <= sbi->s_blocks_per_group)
  		return stripe_width;
  
  	if (stride <= sbi->s_blocks_per_group)
  		return stride;
  
  	return 0;
  }
  
  /* sysfs supprt */
  
  struct ext4_attr {
  	struct attribute attr;
  	ssize_t (*show)(struct ext4_attr *, struct ext4_sb_info *, char *);
  	ssize_t (*store)(struct ext4_attr *, struct ext4_sb_info *,
  			 const char *, size_t);
  	int offset;
  };
  
  static int parse_strtoul(const char *buf,
  		unsigned long max, unsigned long *value)
  {
  	char *endp;
  
  	*value = simple_strtoul(skip_spaces(buf), &endp, 0);
  	endp = skip_spaces(endp);
  	if (*endp || *value > max)
  		return -EINVAL;
  
  	return 0;
  }
  
  static ssize_t delayed_allocation_blocks_show(struct ext4_attr *a,
  					      struct ext4_sb_info *sbi,
  					      char *buf)
  {
  	return snprintf(buf, PAGE_SIZE, "%llu\n",
  			(s64) percpu_counter_sum(&sbi->s_dirtyblocks_counter));
  }
  
  static ssize_t session_write_kbytes_show(struct ext4_attr *a,
  					 struct ext4_sb_info *sbi, char *buf)
  {
  	struct super_block *sb = sbi->s_buddy_cache->i_sb;
  
  	if (!sb->s_bdev->bd_part)
  		return snprintf(buf, PAGE_SIZE, "0\n");
  	return snprintf(buf, PAGE_SIZE, "%lu\n",
  			(part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
  			 sbi->s_sectors_written_start) >> 1);
  }
  
  static ssize_t lifetime_write_kbytes_show(struct ext4_attr *a,
  					  struct ext4_sb_info *sbi, char *buf)
  {
  	struct super_block *sb = sbi->s_buddy_cache->i_sb;
  
  	if (!sb->s_bdev->bd_part)
  		return snprintf(buf, PAGE_SIZE, "0\n");
  	return snprintf(buf, PAGE_SIZE, "%llu\n",
  			(unsigned long long)(sbi->s_kbytes_written +
  			((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
  			  EXT4_SB(sb)->s_sectors_written_start) >> 1)));
  }
  
  static ssize_t extent_cache_hits_show(struct ext4_attr *a,
  				      struct ext4_sb_info *sbi, char *buf)
  {
  	return snprintf(buf, PAGE_SIZE, "%lu\n", sbi->extent_cache_hits);
  }
  
  static ssize_t extent_cache_misses_show(struct ext4_attr *a,
  					struct ext4_sb_info *sbi, char *buf)
  {
  	return snprintf(buf, PAGE_SIZE, "%lu\n", sbi->extent_cache_misses);
  }
  
  static ssize_t inode_readahead_blks_store(struct ext4_attr *a,
  					  struct ext4_sb_info *sbi,
  					  const char *buf, size_t count)
  {
  	unsigned long t;
  
  	if (parse_strtoul(buf, 0x40000000, &t))
  		return -EINVAL;
  
  	if (t && !is_power_of_2(t))
  		return -EINVAL;
  
  	sbi->s_inode_readahead_blks = t;
  	return count;
  }
  
  static ssize_t sbi_ui_show(struct ext4_attr *a,
  			   struct ext4_sb_info *sbi, char *buf)
  {
  	unsigned int *ui = (unsigned int *) (((char *) sbi) + a->offset);
  
  	return snprintf(buf, PAGE_SIZE, "%u\n", *ui);
  }
  
  static ssize_t sbi_ui_store(struct ext4_attr *a,
  			    struct ext4_sb_info *sbi,
  			    const char *buf, size_t count)
  {
  	unsigned int *ui = (unsigned int *) (((char *) sbi) + a->offset);
  	unsigned long t;
  
  	if (parse_strtoul(buf, 0xffffffff, &t))
  		return -EINVAL;
  	*ui = t;
  	return count;
  }
  
  #define EXT4_ATTR_OFFSET(_name,_mode,_show,_store,_elname) \
  static struct ext4_attr ext4_attr_##_name = {			\
  	.attr = {.name = __stringify(_name), .mode = _mode },	\
  	.show	= _show,					\
  	.store	= _store,					\
  	.offset = offsetof(struct ext4_sb_info, _elname),	\
  }
  #define EXT4_ATTR(name, mode, show, store) \
  static struct ext4_attr ext4_attr_##name = __ATTR(name, mode, show, store)
  
  #define EXT4_INFO_ATTR(name) EXT4_ATTR(name, 0444, NULL, NULL)
  #define EXT4_RO_ATTR(name) EXT4_ATTR(name, 0444, name##_show, NULL)
  #define EXT4_RW_ATTR(name) EXT4_ATTR(name, 0644, name##_show, name##_store)
  #define EXT4_RW_ATTR_SBI_UI(name, elname)	\
  	EXT4_ATTR_OFFSET(name, 0644, sbi_ui_show, sbi_ui_store, elname)
  #define ATTR_LIST(name) &ext4_attr_##name.attr
  
  EXT4_RO_ATTR(delayed_allocation_blocks);
  EXT4_RO_ATTR(session_write_kbytes);
  EXT4_RO_ATTR(lifetime_write_kbytes);
  EXT4_RO_ATTR(extent_cache_hits);
  EXT4_RO_ATTR(extent_cache_misses);
  EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, sbi_ui_show,
  		 inode_readahead_blks_store, s_inode_readahead_blks);
  EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
  EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats);
  EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan);
  EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
  EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
  EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
  EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
  EXT4_RW_ATTR_SBI_UI(max_writeback_mb_bump, s_max_writeback_mb_bump);
  
  static struct attribute *ext4_attrs[] = {
  	ATTR_LIST(delayed_allocation_blocks),
  	ATTR_LIST(session_write_kbytes),
  	ATTR_LIST(lifetime_write_kbytes),
  	ATTR_LIST(extent_cache_hits),
  	ATTR_LIST(extent_cache_misses),
  	ATTR_LIST(inode_readahead_blks),
  	ATTR_LIST(inode_goal),
  	ATTR_LIST(mb_stats),
  	ATTR_LIST(mb_max_to_scan),
  	ATTR_LIST(mb_min_to_scan),
  	ATTR_LIST(mb_order2_req),
  	ATTR_LIST(mb_stream_req),
  	ATTR_LIST(mb_group_prealloc),
  	ATTR_LIST(max_writeback_mb_bump),
  	NULL,
  };
  
  /* Features this copy of ext4 supports */
  EXT4_INFO_ATTR(lazy_itable_init);
  EXT4_INFO_ATTR(batched_discard);
  
  static struct attribute *ext4_feat_attrs[] = {
  	ATTR_LIST(lazy_itable_init),
  	ATTR_LIST(batched_discard),
  	NULL,
  };
  
  static ssize_t ext4_attr_show(struct kobject *kobj,
  			      struct attribute *attr, char *buf)
  {
  	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
  						s_kobj);
  	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
  
  	return a->show ? a->show(a, sbi, buf) : 0;
  }
  
  static ssize_t ext4_attr_store(struct kobject *kobj,
  			       struct attribute *attr,
  			       const char *buf, size_t len)
  {
  	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
  						s_kobj);
  	struct ext4_attr *a = container_of(attr, struct ext4_attr, attr);
  
  	return a->store ? a->store(a, sbi, buf, len) : 0;
  }
  
  static void ext4_sb_release(struct kobject *kobj)
  {
  	struct ext4_sb_info *sbi = container_of(kobj, struct ext4_sb_info,
  						s_kobj);
  	complete(&sbi->s_kobj_unregister);
  }
  
  static const struct sysfs_ops ext4_attr_ops = {
  	.show	= ext4_attr_show,
  	.store	= ext4_attr_store,
  };
  
  static struct kobj_type ext4_ktype = {
  	.default_attrs	= ext4_attrs,
  	.sysfs_ops	= &ext4_attr_ops,
  	.release	= ext4_sb_release,
  };
  
  static void ext4_feat_release(struct kobject *kobj)
  {
  	complete(&ext4_feat->f_kobj_unregister);
  }
  
  static struct kobj_type ext4_feat_ktype = {
  	.default_attrs	= ext4_feat_attrs,
  	.sysfs_ops	= &ext4_attr_ops,
  	.release	= ext4_feat_release,
  };
  
  /*
   * Check whether this filesystem can be mounted based on
   * the features present and the RDONLY/RDWR mount requested.
   * Returns 1 if this filesystem can be mounted as requested,
   * 0 if it cannot be.
   */
  static int ext4_feature_set_ok(struct super_block *sb, int readonly)
  {
  	if (EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT4_FEATURE_INCOMPAT_SUPP)) {
  		ext4_msg(sb, KERN_ERR,
  			"Couldn't mount because of "
  			"unsupported optional features (%x)",
  			(le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_incompat) &
  			~EXT4_FEATURE_INCOMPAT_SUPP));
  		return 0;
  	}
  
  	if (readonly)
  		return 1;
  
  	/* Check that feature set is OK for a read-write mount */
  	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT4_FEATURE_RO_COMPAT_SUPP)) {
  		ext4_msg(sb, KERN_ERR, "couldn't mount RDWR because of "
  			 "unsupported optional features (%x)",
  			 (le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_ro_compat) &
  				~EXT4_FEATURE_RO_COMPAT_SUPP));
  		return 0;
  	}
  	/*
  	 * Large file size enabled file system can only be mounted
  	 * read-write on 32-bit systems if kernel is built with CONFIG_LBDAF
  	 */
  	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
  		if (sizeof(blkcnt_t) < sizeof(u64)) {
  			ext4_msg(sb, KERN_ERR, "Filesystem with huge files "
  				 "cannot be mounted RDWR without "
  				 "CONFIG_LBDAF");
  			return 0;
  		}
  	}
  	return 1;
  }
  
  /*
   * This function is called once a day if we have errors logged
   * on the file system
   */
  static void print_daily_error_info(unsigned long arg)
  {
  	struct super_block *sb = (struct super_block *) arg;
  	struct ext4_sb_info *sbi;
  	struct ext4_super_block *es;
  
  	sbi = EXT4_SB(sb);
  	es = sbi->s_es;
  
  	if (es->s_error_count)
  		ext4_msg(sb, KERN_NOTICE, "error count: %u",
  			 le32_to_cpu(es->s_error_count));
  	if (es->s_first_error_time) {
  		printk(KERN_NOTICE "EXT4-fs (%s): initial error at %u: %.*s:%d",
  		       sb->s_id, le32_to_cpu(es->s_first_error_time),
  		       (int) sizeof(es->s_first_error_func),
  		       es->s_first_error_func,
  		       le32_to_cpu(es->s_first_error_line));
  		if (es->s_first_error_ino)
  			printk(": inode %u",
  			       le32_to_cpu(es->s_first_error_ino));
  		if (es->s_first_error_block)
  			printk(": block %llu", (unsigned long long)
  			       le64_to_cpu(es->s_first_error_block));
  		printk("\n");
  	}
  	if (es->s_last_error_time) {
  		printk(KERN_NOTICE "EXT4-fs (%s): last error at %u: %.*s:%d",
  		       sb->s_id, le32_to_cpu(es->s_last_error_time),
  		       (int) sizeof(es->s_last_error_func),
  		       es->s_last_error_func,
  		       le32_to_cpu(es->s_last_error_line));
  		if (es->s_last_error_ino)
  			printk(": inode %u",
  			       le32_to_cpu(es->s_last_error_ino));
  		if (es->s_last_error_block)
  			printk(": block %llu", (unsigned long long)
  			       le64_to_cpu(es->s_last_error_block));
  		printk("\n");
  	}
  	mod_timer(&sbi->s_err_report, jiffies + 24*60*60*HZ);  /* Once a day */
  }
  
  /* Find next suitable group and run ext4_init_inode_table */
  static int ext4_run_li_request(struct ext4_li_request *elr)
  {
  	struct ext4_group_desc *gdp = NULL;
  	ext4_group_t group, ngroups;
  	struct super_block *sb;
  	unsigned long timeout = 0;
  	int ret = 0;
  
  	sb = elr->lr_super;
  	ngroups = EXT4_SB(sb)->s_groups_count;
  
  	for (group = elr->lr_next_group; group < ngroups; group++) {
  		gdp = ext4_get_group_desc(sb, group, NULL);
  		if (!gdp) {
  			ret = 1;
  			break;
  		}
  
  		if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
  			break;
  	}
  
  	if (group == ngroups)
  		ret = 1;
  
  	if (!ret) {
  		timeout = jiffies;
  		ret = ext4_init_inode_table(sb, group,
  					    elr->lr_timeout ? 0 : 1);
  		if (elr->lr_timeout == 0) {
  			timeout = (jiffies - timeout) *
  				  elr->lr_sbi->s_li_wait_mult;
  			elr->lr_timeout = timeout;
  		}
  		elr->lr_next_sched = jiffies + elr->lr_timeout;
  		elr->lr_next_group = group + 1;
  	}
  
  	return ret;
  }
  
  /*
   * Remove lr_request from the list_request and free the
   * request structure. Should be called with li_list_mtx held
   */
  static void ext4_remove_li_request(struct ext4_li_request *elr)
  {
  	struct ext4_sb_info *sbi;
  
  	if (!elr)
  		return;
  
  	sbi = elr->lr_sbi;
  
  	list_del(&elr->lr_request);
  	sbi->s_li_request = NULL;
  	kfree(elr);
  }
  
  static void ext4_unregister_li_request(struct super_block *sb)
  {
  	mutex_lock(&ext4_li_mtx);
  	if (!ext4_li_info) {
  		mutex_unlock(&ext4_li_mtx);
  		return;
  	}
  
  	mutex_lock(&ext4_li_info->li_list_mtx);
  	ext4_remove_li_request(EXT4_SB(sb)->s_li_request);
  	mutex_unlock(&ext4_li_info->li_list_mtx);
  	mutex_unlock(&ext4_li_mtx);
  }
  
  static struct task_struct *ext4_lazyinit_task;
  
  /*
   * This is the function where ext4lazyinit thread lives. It walks
   * through the request list searching for next scheduled filesystem.
   * When such a fs is found, run the lazy initialization request
   * (ext4_rn_li_request) and keep track of the time spend in this
   * function. Based on that time we compute next schedule time of
   * the request. When walking through the list is complete, compute
   * next waking time and put itself into sleep.
   */
  static int ext4_lazyinit_thread(void *arg)
  {
  	struct ext4_lazy_init *eli = (struct ext4_lazy_init *)arg;
  	struct list_head *pos, *n;
  	struct ext4_li_request *elr;
  	unsigned long next_wakeup, cur;
  
  	BUG_ON(NULL == eli);
  
  cont_thread:
  	while (true) {
  		next_wakeup = MAX_JIFFY_OFFSET;
  
  		mutex_lock(&eli->li_list_mtx);
  		if (list_empty(&eli->li_request_list)) {
  			mutex_unlock(&eli->li_list_mtx);
  			goto exit_thread;
  		}
  
  		list_for_each_safe(pos, n, &eli->li_request_list) {
  			elr = list_entry(pos, struct ext4_li_request,
  					 lr_request);
  
  			if (time_after_eq(jiffies, elr->lr_next_sched)) {
  				if (ext4_run_li_request(elr) != 0) {
  					/* error, remove the lazy_init job */
  					ext4_remove_li_request(elr);
  					continue;
  				}
  			}
  
  			if (time_before(elr->lr_next_sched, next_wakeup))
  				next_wakeup = elr->lr_next_sched;
  		}
  		mutex_unlock(&eli->li_list_mtx);
  
  		if (freezing(current))
  			refrigerator();
  
  		cur = jiffies;
  		if ((time_after_eq(cur, next_wakeup)) ||
  		    (MAX_JIFFY_OFFSET == next_wakeup)) {
  			cond_resched();
  			continue;
  		}
  
  		schedule_timeout_interruptible(next_wakeup - cur);
  
  		if (kthread_should_stop()) {
  			ext4_clear_request_list();
  			goto exit_thread;
  		}
  	}
  
  exit_thread:
  	/*
  	 * It looks like the request list is empty, but we need
  	 * to check it under the li_list_mtx lock, to prevent any
  	 * additions into it, and of course we should lock ext4_li_mtx
  	 * to atomically free the list and ext4_li_info, because at
  	 * this point another ext4 filesystem could be registering
  	 * new one.
  	 */
  	mutex_lock(&ext4_li_mtx);
  	mutex_lock(&eli->li_list_mtx);
  	if (!list_empty(&eli->li_request_list)) {
  		mutex_unlock(&eli->li_list_mtx);
  		mutex_unlock(&ext4_li_mtx);
  		goto cont_thread;
  	}
  	mutex_unlock(&eli->li_list_mtx);
  	kfree(ext4_li_info);
  	ext4_li_info = NULL;
  	mutex_unlock(&ext4_li_mtx);
  
  	return 0;
  }
  
  static void ext4_clear_request_list(void)
  {
  	struct list_head *pos, *n;
  	struct ext4_li_request *elr;
  
  	mutex_lock(&ext4_li_info->li_list_mtx);
  	list_for_each_safe(pos, n, &ext4_li_info->li_request_list) {
  		elr = list_entry(pos, struct ext4_li_request,
  				 lr_request);
  		ext4_remove_li_request(elr);
  	}
  	mutex_unlock(&ext4_li_info->li_list_mtx);
  }
  
  static int ext4_run_lazyinit_thread(void)
  {
  	ext4_lazyinit_task = kthread_run(ext4_lazyinit_thread,
  					 ext4_li_info, "ext4lazyinit");
  	if (IS_ERR(ext4_lazyinit_task)) {
  		int err = PTR_ERR(ext4_lazyinit_task);
  		ext4_clear_request_list();
  		kfree(ext4_li_info);
  		ext4_li_info = NULL;
  		printk(KERN_CRIT "EXT4: error %d creating inode table "
  				 "initialization thread\n",
  				 err);
  		return err;
  	}
  	ext4_li_info->li_state |= EXT4_LAZYINIT_RUNNING;
  	return 0;
  }
  
  /*
   * Check whether it make sense to run itable init. thread or not.
   * If there is at least one uninitialized inode table, return
   * corresponding group number, else the loop goes through all
   * groups and return total number of groups.
   */
  static ext4_group_t ext4_has_uninit_itable(struct super_block *sb)
  {
  	ext4_group_t group, ngroups = EXT4_SB(sb)->s_groups_count;
  	struct ext4_group_desc *gdp = NULL;
  
  	for (group = 0; group < ngroups; group++) {
  		gdp = ext4_get_group_desc(sb, group, NULL);
  		if (!gdp)
  			continue;
  
  		if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
  			break;
  	}
  
  	return group;
  }
  
  static int ext4_li_info_new(void)
  {
  	struct ext4_lazy_init *eli = NULL;
  
  	eli = kzalloc(sizeof(*eli), GFP_KERNEL);
  	if (!eli)
  		return -ENOMEM;
  
  	INIT_LIST_HEAD(&eli->li_request_list);
  	mutex_init(&eli->li_list_mtx);
  
  	eli->li_state |= EXT4_LAZYINIT_QUIT;
  
  	ext4_li_info = eli;
  
  	return 0;
  }
  
  static struct ext4_li_request *ext4_li_request_new(struct super_block *sb,
  					    ext4_group_t start)
  {
  	struct ext4_sb_info *sbi = EXT4_SB(sb);
  	struct ext4_li_request *elr;
  	unsigned long rnd;
  
  	elr = kzalloc(sizeof(*elr), GFP_KERNEL);
  	if (!elr)
  		return NULL;
  
  	elr->lr_super = sb;
  	elr->lr_sbi = sbi;
  	elr->lr_next_group = start;
  
  	/*
  	 * Randomize first schedule time of the request to
  	 * spread the inode table initialization requests
  	 * better.
  	 */
  	get_random_bytes(&rnd, sizeof(rnd));
  	elr->lr_next_sched = jiffies + (unsigned long)rnd %
  			     (EXT4_DEF_LI_MAX_START_DELAY * HZ);
  
  	return elr;
  }
  
  static int ext4_register_li_request(struct super_block *sb,
  				    ext4_group_t first_not_zeroed)
  {
  	struct ext4_sb_info *sbi = EXT4_SB(sb);
  	struct ext4_li_request *elr;
  	ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
  	int ret = 0;
  
  	if (sbi->s_li_request != NULL) {
  		/*
  		 * Reset timeout so it can be computed again, because
  		 * s_li_wait_mult might have changed.
  		 */
  		sbi->s_li_request->lr_timeout = 0;
  		return 0;
  	}
  
  	if (first_not_zeroed == ngroups ||
  	    (sb->s_flags & MS_RDONLY) ||
  	    !test_opt(sb, INIT_INODE_TABLE))
  		return 0;
  
  	elr = ext4_li_request_new(sb, first_not_zeroed);
  	if (!elr)
  		return -ENOMEM;
  
  	mutex_lock(&ext4_li_mtx);
  
  	if (NULL == ext4_li_info) {
  		ret = ext4_li_info_new();
  		if (ret)
  			goto out;
  	}
  
  	mutex_lock(&ext4_li_info->li_list_mtx);
  	list_add(&elr->lr_request, &ext4_li_info->li_request_list);
  	mutex_unlock(&ext4_li_info->li_list_mtx);
  
  	sbi->s_li_request = elr;
  	/*
  	 * set elr to NULL here since it has been inserted to
  	 * the request_list and the removal and free of it is
  	 * handled by ext4_clear_request_list from now on.
  	 */
  	elr = NULL;
  
  	if (!(ext4_li_info->li_state & EXT4_LAZYINIT_RUNNING)) {
  		ret = ext4_run_lazyinit_thread();
  		if (ret)
  			goto out;
  	}
  out:
  	mutex_unlock(&ext4_li_mtx);
  	if (ret)
  		kfree(elr);
  	return ret;
  }
  
  /*
   * We do not need to lock anything since this is called on
   * module unload.
   */
  static void ext4_destroy_lazyinit_thread(void)
  {
  	/*
  	 * If thread exited earlier
  	 * there's nothing to be done.
  	 */
  	if (!ext4_li_info || !ext4_lazyinit_task)
  		return;
  
  	kthread_stop(ext4_lazyinit_task);
  }
  
  static int ext4_fill_super(struct super_block *sb, void *data, int silent)
  				__releases(kernel_lock)
  				__acquires(kernel_lock)
  {
  	char *orig_data = kstrdup(data, GFP_KERNEL);
  	struct buffer_head *bh;
  	struct ext4_super_block *es = NULL;
  	struct ext4_sb_info *sbi;
  	ext4_fsblk_t block;
  	ext4_fsblk_t sb_block = get_sb_block(&data);
  	ext4_fsblk_t logical_sb_block;
  	unsigned long offset = 0;
  	unsigned long journal_devnum = 0;
  	unsigned long def_mount_opts;
  	struct inode *root;
  	char *cp;
  	const char *descr;
  	int ret = -ENOMEM;
  	int blocksize;
  	unsigned int db_count;
  	unsigned int i;
  	int needs_recovery, has_huge_files;
  	__u64 blocks_count;
  	int err;
  	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
  	ext4_group_t first_not_zeroed;
  
  	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
  	if (!sbi)
  		goto out_free_orig;
  
  	sbi->s_blockgroup_lock =
  		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
  	if (!sbi->s_blockgroup_lock) {
  		kfree(sbi);
  		goto out_free_orig;
  	}
  	sb->s_fs_info = sbi;
  	sbi->s_mount_opt = 0;
  	sbi->s_resuid = EXT4_DEF_RESUID;
  	sbi->s_resgid = EXT4_DEF_RESGID;
  	sbi->s_inode_readahead_blks = EXT4_DEF_INODE_READAHEAD_BLKS;
  	sbi->s_sb_block = sb_block;
  	if (sb->s_bdev->bd_part)
  		sbi->s_sectors_written_start =
  			part_stat_read(sb->s_bdev->bd_part, sectors[1]);
  
  	/* Cleanup superblock name */
  	for (cp = sb->s_id; (cp = strchr(cp, '/'));)
  		*cp = '!';
  
  	ret = -EINVAL;
  	blocksize = sb_min_blocksize(sb, EXT4_MIN_BLOCK_SIZE);
  	if (!blocksize) {
  		ext4_msg(sb, KERN_ERR, "unable to set blocksize");
  		goto out_fail;
  	}
  
  	/*
  	 * The ext4 superblock will not be buffer aligned for other than 1kB
  	 * block sizes.  We need to calculate the offset from buffer start.
  	 */
  	if (blocksize != EXT4_MIN_BLOCK_SIZE) {
  		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
  		offset = do_div(logical_sb_block, blocksize);
  	} else {
  		logical_sb_block = sb_block;
  	}
  
  	if (!(bh = sb_bread(sb, logical_sb_block))) {
  		ext4_msg(sb, KERN_ERR, "unable to read superblock");
  		goto out_fail;
  	}
  	/*
  	 * Note: s_es must be initialized as soon as possible because
  	 *       some ext4 macro-instructions depend on its value
  	 */
  	es = (struct ext4_super_block *) (((char *)bh->b_data) + offset);
  	sbi->s_es = es;
  	sb->s_magic = le16_to_cpu(es->s_magic);
  	if (sb->s_magic != EXT4_SUPER_MAGIC)
  		goto cantfind_ext4;
  	sbi->s_kbytes_written = le64_to_cpu(es->s_kbytes_written);
  
  	/* Set defaults before we parse the mount options */
  	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
  	set_opt(sb, INIT_INODE_TABLE);
  	if (def_mount_opts & EXT4_DEFM_DEBUG)
  		set_opt(sb, DEBUG);
  	if (def_mount_opts & EXT4_DEFM_BSDGROUPS) {
  		ext4_msg(sb, KERN_WARNING, deprecated_msg, "bsdgroups",
  			"2.6.38");
  		set_opt(sb, GRPID);
  	}
  	if (def_mount_opts & EXT4_DEFM_UID16)
  		set_opt(sb, NO_UID32);
  	/* xattr user namespace & acls are now defaulted on */
  #ifdef CONFIG_EXT4_FS_XATTR
  	set_opt(sb, XATTR_USER);
  #endif
  #ifdef CONFIG_EXT4_FS_POSIX_ACL
  	set_opt(sb, POSIX_ACL);
  #endif
  	set_opt(sb, MBLK_IO_SUBMIT);
  	if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_DATA)
  		set_opt(sb, JOURNAL_DATA);
  	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_ORDERED)
  		set_opt(sb, ORDERED_DATA);
  	else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_WBACK)
  		set_opt(sb, WRITEBACK_DATA);
  
  	if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_PANIC)
  		set_opt(sb, ERRORS_PANIC);
  	else if (le16_to_cpu(sbi->s_es->s_errors) == EXT4_ERRORS_CONTINUE)
  		set_opt(sb, ERRORS_CONT);
  	else
  		set_opt(sb, ERRORS_RO);
  	if (def_mount_opts & EXT4_DEFM_BLOCK_VALIDITY)
  		set_opt(sb, BLOCK_VALIDITY);
  	if (def_mount_opts & EXT4_DEFM_DISCARD)
  		set_opt(sb, DISCARD);
  
  	sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
  	sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
  	sbi->s_commit_interval = JBD2_DEFAULT_MAX_COMMIT_AGE * HZ;
  	sbi->s_min_batch_time = EXT4_DEF_MIN_BATCH_TIME;
  	sbi->s_max_batch_time = EXT4_DEF_MAX_BATCH_TIME;
  
  	if ((def_mount_opts & EXT4_DEFM_NOBARRIER) == 0)
  		set_opt(sb, BARRIER);
  
  	/*
  	 * enable delayed allocation by default
  	 * Use -o nodelalloc to turn it off
  	 */
  	if (!IS_EXT3_SB(sb) &&
  	    ((def_mount_opts & EXT4_DEFM_NODELALLOC) == 0))
  		set_opt(sb, DELALLOC);
  
  	/*
  	 * set default s_li_wait_mult for lazyinit, for the case there is
  	 * no mount option specified.
  	 */
  	sbi->s_li_wait_mult = EXT4_DEF_LI_WAIT_MULT;
  
  	if (!parse_options((char *) sbi->s_es->s_mount_opts, sb,
  			   &journal_devnum, &journal_ioprio, NULL, 0)) {
  		ext4_msg(sb, KERN_WARNING,
  			 "failed to parse options in superblock: %s",
  			 sbi->s_es->s_mount_opts);
  	}
  	if (!parse_options((char *) data, sb, &journal_devnum,
  			   &journal_ioprio, NULL, 0))
  		goto failed_mount;
  
  	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
  		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
  
  	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV &&
  	    (EXT4_HAS_COMPAT_FEATURE(sb, ~0U) ||
  	     EXT4_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
  	     EXT4_HAS_INCOMPAT_FEATURE(sb, ~0U)))
  		ext4_msg(sb, KERN_WARNING,
  		       "feature flags set on rev 0 fs, "
  		       "running e2fsck is recommended");
  
  	if (IS_EXT2_SB(sb)) {
  		if (ext2_feature_set_ok(sb))
  			ext4_msg(sb, KERN_INFO, "mounting ext2 file system "
  				 "using the ext4 subsystem");
  		else {
  			ext4_msg(sb, KERN_ERR, "couldn't mount as ext2 due "
  				 "to feature incompatibilities");
  			goto failed_mount;
  		}
  	}
  
  	if (IS_EXT3_SB(sb)) {
  		if (ext3_feature_set_ok(sb))
  			ext4_msg(sb, KERN_INFO, "mounting ext3 file system "
  				 "using the ext4 subsystem");
  		else {
  			ext4_msg(sb, KERN_ERR, "couldn't mount as ext3 due "
  				 "to feature incompatibilities");
  			goto failed_mount;
  		}
  	}
  
  	/*
  	 * 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.
  	 */
  	if (!ext4_feature_set_ok(sb, (sb->s_flags & MS_RDONLY)))
  		goto failed_mount;
  
  	blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);
  
  	if (blocksize < EXT4_MIN_BLOCK_SIZE ||
  	    blocksize > EXT4_MAX_BLOCK_SIZE) {
  		ext4_msg(sb, KERN_ERR,
  		       "Unsupported filesystem blocksize %d", blocksize);
  		goto failed_mount;
  	}
  
  	if (sb->s_blocksize != blocksize) {
  		/* Validate the filesystem blocksize */
  		if (!sb_set_blocksize(sb, blocksize)) {
  			ext4_msg(sb, KERN_ERR, "bad block size %d",
  					blocksize);
  			goto failed_mount;
  		}
  
  		brelse(bh);
  		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
  		offset = do_div(logical_sb_block, blocksize);
  		bh = sb_bread(sb, logical_sb_block);
  		if (!bh) {
  			ext4_msg(sb, KERN_ERR,
  			       "Can't read superblock on 2nd try");
  			goto failed_mount;
  		}
  		es = (struct ext4_super_block *)(((char *)bh->b_data) + offset);
  		sbi->s_es = es;
  		if (es->s_magic != cpu_to_le16(EXT4_SUPER_MAGIC)) {
  			ext4_msg(sb, KERN_ERR,
  			       "Magic mismatch, very weird!");
  			goto failed_mount;
  		}
  	}
  
  	has_huge_files = EXT4_HAS_RO_COMPAT_FEATURE(sb,
  				EXT4_FEATURE_RO_COMPAT_HUGE_FILE);
  	sbi->s_bitmap_maxbytes = ext4_max_bitmap_size(sb->s_blocksize_bits,
  						      has_huge_files);
  	sb->s_maxbytes = ext4_max_size(sb->s_blocksize_bits, has_huge_files);
  
  	if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV) {
  		sbi->s_inode_size = EXT4_GOOD_OLD_INODE_SIZE;
  		sbi->s_first_ino = EXT4_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 < EXT4_GOOD_OLD_INODE_SIZE) ||
  		    (!is_power_of_2(sbi->s_inode_size)) ||
  		    (sbi->s_inode_size > blocksize)) {
  			ext4_msg(sb, KERN_ERR,
  			       "unsupported inode size: %d",
  			       sbi->s_inode_size);
  			goto failed_mount;
  		}
  		if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE)
  			sb->s_time_gran = 1 << (EXT4_EPOCH_BITS - 2);
  	}
  
  	sbi->s_desc_size = le16_to_cpu(es->s_desc_size);
  	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT)) {
  		if (sbi->s_desc_size < EXT4_MIN_DESC_SIZE_64BIT ||
  		    sbi->s_desc_size > EXT4_MAX_DESC_SIZE ||
  		    !is_power_of_2(sbi->s_desc_size)) {
  			ext4_msg(sb, KERN_ERR,
  			       "unsupported descriptor size %lu",
  			       sbi->s_desc_size);
  			goto failed_mount;
  		}
  	} else
  		sbi->s_desc_size = EXT4_MIN_DESC_SIZE;
  
  	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
  	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
  	if (EXT4_INODE_SIZE(sb) == 0 || EXT4_INODES_PER_GROUP(sb) == 0)
  		goto cantfind_ext4;
  
  	sbi->s_inodes_per_block = blocksize / EXT4_INODE_SIZE(sb);
  	if (sbi->s_inodes_per_block == 0)
  		goto cantfind_ext4;
  	sbi->s_itb_per_group = sbi->s_inodes_per_group /
  					sbi->s_inodes_per_block;
  	sbi->s_desc_per_block = blocksize / EXT4_DESC_SIZE(sb);
  	sbi->s_sbh = bh;
  	sbi->s_mount_state = le16_to_cpu(es->s_state);
  	sbi->s_addr_per_block_bits = ilog2(EXT4_ADDR_PER_BLOCK(sb));
  	sbi->s_desc_per_block_bits = ilog2(EXT4_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;
  	i = le32_to_cpu(es->s_flags);
  	if (i & EXT2_FLAGS_UNSIGNED_HASH)
  		sbi->s_hash_unsigned = 3;
  	else if ((i & EXT2_FLAGS_SIGNED_HASH) == 0) {
  #ifdef __CHAR_UNSIGNED__
  		es->s_flags |= cpu_to_le32(EXT2_FLAGS_UNSIGNED_HASH);
  		sbi->s_hash_unsigned = 3;
  #else
  		es->s_flags |= cpu_to_le32(EXT2_FLAGS_SIGNED_HASH);
  #endif
  		sb->s_dirt = 1;
  	}
  
  	if (sbi->s_blocks_per_group > blocksize * 8) {
  		ext4_msg(sb, KERN_ERR,
  		       "#blocks per group too big: %lu",
  		       sbi->s_blocks_per_group);
  		goto failed_mount;
  	}
  	if (sbi->s_inodes_per_group > blocksize * 8) {
  		ext4_msg(sb, KERN_ERR,
  		       "#inodes per group too big: %lu",
  		       sbi->s_inodes_per_group);
  		goto failed_mount;
  	}
  
  	/*
  	 * Test whether we have more sectors than will fit in sector_t,
  	 * and whether the max offset is addressable by the page cache.
  	 */
  	err = generic_check_addressable(sb->s_blocksize_bits,
  					ext4_blocks_count(es));
  	if (err) {
  		ext4_msg(sb, KERN_ERR, "filesystem"
  			 " too large to mount safely on this system");
  		if (sizeof(sector_t) < 8)
  			ext4_msg(sb, KERN_WARNING, "CONFIG_LBDAF not enabled");
  		ret = err;
  		goto failed_mount;
  	}
  
  	if (EXT4_BLOCKS_PER_GROUP(sb) == 0)
  		goto cantfind_ext4;
  
  	/* check blocks count against device size */
  	blocks_count = sb->s_bdev->bd_inode->i_size >> sb->s_blocksize_bits;
  	if (blocks_count && ext4_blocks_count(es) > blocks_count) {
  		ext4_msg(sb, KERN_WARNING, "bad geometry: block count %llu "
  		       "exceeds size of device (%llu blocks)",
  		       ext4_blocks_count(es), blocks_count);
  		goto failed_mount;
  	}
  
  	/*
  	 * It makes no sense for the first data block to be beyond the end
  	 * of the filesystem.
  	 */
  	if (le32_to_cpu(es->s_first_data_block) >= ext4_blocks_count(es)) {
                  ext4_msg(sb, KERN_WARNING, "bad geometry: first data"
  			 "block %u is beyond end of filesystem (%llu)",
  			 le32_to_cpu(es->s_first_data_block),
  			 ext4_blocks_count(es));
  		goto failed_mount;
  	}
  	blocks_count = (ext4_blocks_count(es) -
  			le32_to_cpu(es->s_first_data_block) +
  			EXT4_BLOCKS_PER_GROUP(sb) - 1);
  	do_div(blocks_count, EXT4_BLOCKS_PER_GROUP(sb));
  	if (blocks_count > ((uint64_t)1<<32) - EXT4_DESC_PER_BLOCK(sb)) {
  		ext4_msg(sb, KERN_WARNING, "groups count too large: %u "
  		       "(block count %llu, first data block %u, "
  		       "blocks per group %lu)", sbi->s_groups_count,
  		       ext4_blocks_count(es),
  		       le32_to_cpu(es->s_first_data_block),
  		       EXT4_BLOCKS_PER_GROUP(sb));
  		goto failed_mount;
  	}
  	sbi->s_groups_count = blocks_count;
  	sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
  			(EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
  	db_count = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
  		   EXT4_DESC_PER_BLOCK(sb);
  	sbi->s_group_desc = kmalloc(db_count * sizeof(struct buffer_head *),
  				    GFP_KERNEL);
  	if (sbi->s_group_desc == NULL) {
  		ext4_msg(sb, KERN_ERR, "not enough memory");
  		goto failed_mount;
  	}
  
  #ifdef CONFIG_PROC_FS
  	if (ext4_proc_root)
  		sbi->s_proc = proc_mkdir(sb->s_id, ext4_proc_root);
  #endif
  
  	bgl_lock_init(sbi->s_blockgroup_lock);
  
  	for (i = 0; i < db_count; i++) {
  		block = descriptor_loc(sb, logical_sb_block, i);
  		sbi->s_group_desc[i] = sb_bread(sb, block);
  		if (!sbi->s_group_desc[i]) {
  			ext4_msg(sb, KERN_ERR,
  			       "can't read group descriptor %d", i);
  			db_count = i;
  			goto failed_mount2;
  		}
  	}
  	if (!ext4_check_descriptors(sb, &first_not_zeroed)) {
  		ext4_msg(sb, KERN_ERR, "group descriptors corrupted!");
  		goto failed_mount2;
  	}
  	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
  		if (!ext4_fill_flex_info(sb)) {
  			ext4_msg(sb, KERN_ERR,
  			       "unable to initialize "
  			       "flex_bg meta info!");
  			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);
  
  	init_timer(&sbi->s_err_report);
  	sbi->s_err_report.function = print_daily_error_info;
  	sbi->s_err_report.data = (unsigned long) sb;
  
  	err = percpu_counter_init(&sbi->s_freeblocks_counter,
  			ext4_count_free_blocks(sb));
  	if (!err) {
  		err = percpu_counter_init(&sbi->s_freeinodes_counter,
  				ext4_count_free_inodes(sb));
  	}
  	if (!err) {
  		err = percpu_counter_init(&sbi->s_dirs_counter,
  				ext4_count_dirs(sb));
  	}
  	if (!err) {
  		err = percpu_counter_init(&sbi->s_dirtyblocks_counter, 0);
  	}
  	if (err) {
  		ext4_msg(sb, KERN_ERR, "insufficient memory");
  		goto failed_mount3;
  	}
  
  	sbi->s_stripe = ext4_get_stripe_size(sbi);
  	sbi->s_max_writeback_mb_bump = 128;
  
  	/*
  	 * set up enough so that it can read an inode
  	 */
  	if (!test_opt(sb, NOLOAD) &&
  	    EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL))
  		sb->s_op = &ext4_sops;
  	else
  		sb->s_op = &ext4_nojournal_sops;
  	sb->s_export_op = &ext4_export_ops;
  	sb->s_xattr = ext4_xattr_handlers;
  #ifdef CONFIG_QUOTA
  	sb->s_qcop = &ext4_qctl_operations;
  	sb->dq_op = &ext4_quota_operations;
  #endif
  	memcpy(sb->s_uuid, es->s_uuid, sizeof(es->s_uuid));
  
  	INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */
  	mutex_init(&sbi->s_orphan_lock);
  	mutex_init(&sbi->s_resize_lock);
  
  	sb->s_root = NULL;
  
  	needs_recovery = (es->s_last_orphan != 0 ||
  			  EXT4_HAS_INCOMPAT_FEATURE(sb,
  				    EXT4_FEATURE_INCOMPAT_RECOVER));
  
  	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_MMP) &&
  	    !(sb->s_flags & MS_RDONLY))
  		if (ext4_multi_mount_protect(sb, le64_to_cpu(es->s_mmp_block)))
  			goto failed_mount3;
  
  	/*
  	 * 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) &&
  	    EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL)) {
  		if (ext4_load_journal(sb, es, journal_devnum))
  			goto failed_mount3;
  	} else if (test_opt(sb, NOLOAD) && !(sb->s_flags & MS_RDONLY) &&
  	      EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER)) {
  		ext4_msg(sb, KERN_ERR, "required journal recovery "
  		       "suppressed and not mounted read-only");
  		goto failed_mount_wq;
  	} else {
  		clear_opt(sb, DATA_FLAGS);
  		sbi->s_journal = NULL;
  		needs_recovery = 0;
  		goto no_journal;
  	}
  
  	if (ext4_blocks_count(es) > 0xffffffffULL &&
  	    !jbd2_journal_set_features(EXT4_SB(sb)->s_journal, 0, 0,
  				       JBD2_FEATURE_INCOMPAT_64BIT)) {
  		ext4_msg(sb, KERN_ERR, "Failed to set 64-bit journal feature");
  		goto failed_mount_wq;
  	}
  
  	if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
  		jbd2_journal_set_features(sbi->s_journal,
  				JBD2_FEATURE_COMPAT_CHECKSUM, 0,
  				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
  	} else if (test_opt(sb, JOURNAL_CHECKSUM)) {
  		jbd2_journal_set_features(sbi->s_journal,
  				JBD2_FEATURE_COMPAT_CHECKSUM, 0, 0);
  		jbd2_journal_clear_features(sbi->s_journal, 0, 0,
  				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
  	} else {
  		jbd2_journal_clear_features(sbi->s_journal,
  				JBD2_FEATURE_COMPAT_CHECKSUM, 0,
  				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
  	}
  
  	/* 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 (jbd2_journal_check_available_features
  		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE))
  			set_opt(sb, ORDERED_DATA);
  		else
  			set_opt(sb, JOURNAL_DATA);
  		break;
  
  	case EXT4_MOUNT_ORDERED_DATA:
  	case EXT4_MOUNT_WRITEBACK_DATA:
  		if (!jbd2_journal_check_available_features
  		    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)) {
  			ext4_msg(sb, KERN_ERR, "Journal does not support "
  			       "requested data journaling mode");
  			goto failed_mount_wq;
  		}
  	default:
  		break;
  	}
  	set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
  
  	/*
  	 * The journal may have updated the bg summary counts, so we
  	 * need to update the global counters.
  	 */
  	percpu_counter_set(&sbi->s_freeblocks_counter,
  			   ext4_count_free_blocks(sb));
  	percpu_counter_set(&sbi->s_freeinodes_counter,
  			   ext4_count_free_inodes(sb));
  	percpu_counter_set(&sbi->s_dirs_counter,
  			   ext4_count_dirs(sb));
  	percpu_counter_set(&sbi->s_dirtyblocks_counter, 0);
  
  no_journal:
  	/*
  	 * The maximum number of concurrent works can be high and
  	 * concurrency isn't really necessary.  Limit it to 1.
  	 */
  	EXT4_SB(sb)->dio_unwritten_wq =
  		alloc_workqueue("ext4-dio-unwritten", WQ_MEM_RECLAIM | WQ_UNBOUND, 1);
  	if (!EXT4_SB(sb)->dio_unwritten_wq) {
  		printk(KERN_ERR "EXT4-fs: failed to create DIO workqueue\n");
  		goto failed_mount_wq;
  	}
  
  	/*
  	 * The jbd2_journal_load will have done any necessary log recovery,
  	 * so we can safely mount the rest of the filesystem now.
  	 */
  
  	root = ext4_iget(sb, EXT4_ROOT_INO);
  	if (IS_ERR(root)) {
  		ext4_msg(sb, KERN_ERR, "get root inode failed");
  		ret = PTR_ERR(root);
  		root = NULL;
  		goto failed_mount4;
  	}
  	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
  		ext4_msg(sb, KERN_ERR, "corrupt root inode, run e2fsck");
  		goto failed_mount4;
  	}
  	sb->s_root = d_alloc_root(root);
  	if (!sb->s_root) {
  		ext4_msg(sb, KERN_ERR, "get root dentry failed");
  		ret = -ENOMEM;
  		goto failed_mount4;
  	}
  
  	if (ext4_setup_super(sb, es, sb->s_flags & MS_RDONLY))
  		sb->s_flags |= MS_RDONLY;
  
  	/* determine the minimum size of new large inodes, if present */
  	if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
  		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
  						     EXT4_GOOD_OLD_INODE_SIZE;
  		if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
  				       EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE)) {
  			if (sbi->s_want_extra_isize <
  			    le16_to_cpu(es->s_want_extra_isize))
  				sbi->s_want_extra_isize =
  					le16_to_cpu(es->s_want_extra_isize);
  			if (sbi->s_want_extra_isize <
  			    le16_to_cpu(es->s_min_extra_isize))
  				sbi->s_want_extra_isize =
  					le16_to_cpu(es->s_min_extra_isize);
  		}
  	}
  	/* Check if enough inode space is available */
  	if (EXT4_GOOD_OLD_INODE_SIZE + sbi->s_want_extra_isize >
  							sbi->s_inode_size) {
  		sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
  						       EXT4_GOOD_OLD_INODE_SIZE;
  		ext4_msg(sb, KERN_INFO, "required extra inode space not"
  			 "available");
  	}
  
  	if (test_opt(sb, DELALLOC) &&
  	    (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)) {
  		ext4_msg(sb, KERN_WARNING, "Ignoring delalloc option - "
  			 "requested data journaling mode");
  		clear_opt(sb, DELALLOC);
  	}
  	if (test_opt(sb, DIOREAD_NOLOCK)) {
  		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
  			ext4_msg(sb, KERN_WARNING, "Ignoring dioread_nolock "
  				"option - requested data journaling mode");
  			clear_opt(sb, DIOREAD_NOLOCK);
  		}
  		if (sb->s_blocksize < PAGE_SIZE) {
  			ext4_msg(sb, KERN_WARNING, "Ignoring dioread_nolock "
  				"option - block size is too small");
  			clear_opt(sb, DIOREAD_NOLOCK);
  		}
  	}
  
  	err = ext4_setup_system_zone(sb);
  	if (err) {
  		ext4_msg(sb, KERN_ERR, "failed to initialize system "
  			 "zone (%d)", err);
  		goto failed_mount4;
  	}
  
  	ext4_ext_init(sb);
  	err = ext4_mb_init(sb, needs_recovery);
  	if (err) {
  		ext4_msg(sb, KERN_ERR, "failed to initialize mballoc (%d)",
  			 err);
  		goto failed_mount5;
  	}
  
  	err = ext4_register_li_request(sb, first_not_zeroed);
  	if (err)
  		goto failed_mount6;
  
  	sbi->s_kobj.kset = ext4_kset;
  	init_completion(&sbi->s_kobj_unregister);
  	err = kobject_init_and_add(&sbi->s_kobj, &ext4_ktype, NULL,
  				   "%s", sb->s_id);
  	if (err)
  		goto failed_mount7;
  
  	EXT4_SB(sb)->s_mount_state |= EXT4_ORPHAN_FS;
  	ext4_orphan_cleanup(sb, es);
  	EXT4_SB(sb)->s_mount_state &= ~EXT4_ORPHAN_FS;
  	if (needs_recovery) {
  		ext4_msg(sb, KERN_INFO, "recovery complete");
  		ext4_mark_recovery_complete(sb, es);
  	}
  	if (EXT4_SB(sb)->s_journal) {
  		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
  			descr = " journalled data mode";
  		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
  			descr = " ordered data mode";
  		else
  			descr = " writeback data mode";
  	} else
  		descr = "out journal";
  
  	ext4_msg(sb, KERN_INFO, "mounted filesystem with%s. "
  		 "Opts: %s%s%s", descr, sbi->s_es->s_mount_opts,
  		 *sbi->s_es->s_mount_opts ? "; " : "", orig_data);
  
  	if (es->s_error_count)
  		mod_timer(&sbi->s_err_report, jiffies + 300*HZ); /* 5 minutes */
  
  	kfree(orig_data);
  	return 0;
  
  cantfind_ext4:
  	if (!silent)
  		ext4_msg(sb, KERN_ERR, "VFS: Can't find ext4 filesystem");
  	goto failed_mount;
  
  failed_mount7:
  	ext4_unregister_li_request(sb);
  failed_mount6:
  	ext4_ext_release(sb);
  failed_mount5:
  	ext4_mb_release(sb);
  	ext4_release_system_zone(sb);
  failed_mount4:
  	iput(root);
  	sb->s_root = NULL;
  	ext4_msg(sb, KERN_ERR, "mount failed");
  	destroy_workqueue(EXT4_SB(sb)->dio_unwritten_wq);
  failed_mount_wq:
  	if (sbi->s_journal) {
  		jbd2_journal_destroy(sbi->s_journal);
  		sbi->s_journal = NULL;
  	}
  failed_mount3:
  	del_timer(&sbi->s_err_report);
  	if (sbi->s_flex_groups) {
  		if (is_vmalloc_addr(sbi->s_flex_groups))
  			vfree(sbi->s_flex_groups);
  		else
  			kfree(sbi->s_flex_groups);
  	}
  	percpu_counter_destroy(&sbi->s_freeblocks_counter);
  	percpu_counter_destroy(&sbi->s_freeinodes_counter);
  	percpu_counter_destroy(&sbi->s_dirs_counter);
  	percpu_counter_destroy(&sbi->s_dirtyblocks_counter);
  	if (sbi->s_mmp_tsk)
  		kthread_stop(sbi->s_mmp_tsk);
  failed_mount2:
  	for (i = 0; i < db_count; i++)
  		brelse(sbi->s_group_desc[i]);
  	kfree(sbi->s_group_desc);
  failed_mount:
  	if (sbi->s_proc) {
  		remove_proc_entry(sb->s_id, ext4_proc_root);
  	}
  #ifdef CONFIG_QUOTA
  	for (i = 0; i < MAXQUOTAS; i++)
  		kfree(sbi->s_qf_names[i]);
  #endif
  	ext4_blkdev_remove(sbi);
  	brelse(bh);
  out_fail:
  	sb->s_fs_info = NULL;
  	kfree(sbi->s_blockgroup_lock);
  	kfree(sbi);
  out_free_orig:
  	kfree(orig_data);
  	return ret;
  }
  
  /*
   * 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 ext4_init_journal_params(struct super_block *sb, journal_t *journal)
  {
  	struct ext4_sb_info *sbi = EXT4_SB(sb);
  
  	journal->j_commit_interval = sbi->s_commit_interval;
  	journal->j_min_batch_time = sbi->s_min_batch_time;
  	journal->j_max_batch_time = sbi->s_max_batch_time;
  
  	write_lock(&journal->j_state_lock);
  	if (test_opt(sb, BARRIER))
  		journal->j_flags |= JBD2_BARRIER;
  	else
  		journal->j_flags &= ~JBD2_BARRIER;
  	if (test_opt(sb, DATA_ERR_ABORT))
  		journal->j_flags |= JBD2_ABORT_ON_SYNCDATA_ERR;
  	else
  		journal->j_flags &= ~JBD2_ABORT_ON_SYNCDATA_ERR;
  	write_unlock(&journal->j_state_lock);
  }
  
  static journal_t *ext4_get_journal(struct super_block *sb,
  				   unsigned int journal_inum)
  {
  	struct inode *journal_inode;
  	journal_t *journal;
  
  	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_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 = ext4_iget(sb, journal_inum);
  	if (IS_ERR(journal_inode)) {
  		ext4_msg(sb, KERN_ERR, "no journal found");
  		return NULL;
  	}
  	if (!journal_inode->i_nlink) {
  		make_bad_inode(journal_inode);
  		iput(journal_inode);
  		ext4_msg(sb, KERN_ERR, "journal inode is deleted");
  		return NULL;
  	}
  
  	jbd_debug(2, "Journal inode found at %p: %lld bytes\n",
  		  journal_inode, journal_inode->i_size);
  	if (!S_ISREG(journal_inode->i_mode)) {
  		ext4_msg(sb, KERN_ERR, "invalid journal inode");
  		iput(journal_inode);
  		return NULL;
  	}
  
  	journal = jbd2_journal_init_inode(journal_inode);
  	if (!journal) {
  		ext4_msg(sb, KERN_ERR, "Could not load journal inode");
  		iput(journal_inode);
  		return NULL;
  	}
  	journal->j_private = sb;
  	ext4_init_journal_params(sb, journal);
  	return journal;
  }
  
  static journal_t *ext4_get_dev_journal(struct super_block *sb,
  				       dev_t j_dev)
  {
  	struct buffer_head *bh;
  	journal_t *journal;
  	ext4_fsblk_t start;
  	ext4_fsblk_t len;
  	int hblock, blocksize;
  	ext4_fsblk_t sb_block;
  	unsigned long offset;
  	struct ext4_super_block *es;
  	struct block_device *bdev;
  
  	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
  
  	bdev = ext4_blkdev_get(j_dev, sb);
  	if (bdev == NULL)
  		return NULL;
  
  	blocksize = sb->s_blocksize;
  	hblock = bdev_logical_block_size(bdev);
  	if (blocksize < hblock) {
  		ext4_msg(sb, KERN_ERR,
  			"blocksize too small for journal device");
  		goto out_bdev;
  	}
  
  	sb_block = EXT4_MIN_BLOCK_SIZE / blocksize;
  	offset = EXT4_MIN_BLOCK_SIZE % blocksize;
  	set_blocksize(bdev, blocksize);
  	if (!(bh = __bread(bdev, sb_block, blocksize))) {
  		ext4_msg(sb, KERN_ERR, "couldn't read superblock of "
  		       "external journal");
  		goto out_bdev;
  	}
  
  	es = (struct ext4_super_block *) (((char *)bh->b_data) + offset);
  	if ((le16_to_cpu(es->s_magic) != EXT4_SUPER_MAGIC) ||
  	    !(le32_to_cpu(es->s_feature_incompat) &
  	      EXT4_FEATURE_INCOMPAT_JOURNAL_DEV)) {
  		ext4_msg(sb, KERN_ERR, "external journal has "
  					"bad superblock");
  		brelse(bh);
  		goto out_bdev;
  	}
  
  	if (memcmp(EXT4_SB(sb)->s_es->s_journal_uuid, es->s_uuid, 16)) {
  		ext4_msg(sb, KERN_ERR, "journal UUID does not match");
  		brelse(bh);
  		goto out_bdev;
  	}
  
  	len = ext4_blocks_count(es);
  	start = sb_block + 1;
  	brelse(bh);	/* we're done with the superblock */
  
  	journal = jbd2_journal_init_dev(bdev, sb->s_bdev,
  					start, len, blocksize);
  	if (!journal) {
  		ext4_msg(sb, KERN_ERR, "failed to create device journal");
  		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)) {
  		ext4_msg(sb, KERN_ERR, "I/O error on journal device");
  		goto out_journal;
  	}
  	if (be32_to_cpu(journal->j_superblock->s_nr_users) != 1) {
  		ext4_msg(sb, KERN_ERR, "External journal has more than one "
  					"user (unsupported) - %d",
  			be32_to_cpu(journal->j_superblock->s_nr_users));
  		goto out_journal;
  	}
  	EXT4_SB(sb)->journal_bdev = bdev;
  	ext4_init_journal_params(sb, journal);
  	return journal;
  
  out_journal:
  	jbd2_journal_destroy(journal);
  out_bdev:
  	ext4_blkdev_put(bdev);
  	return NULL;
  }
  
  static int ext4_load_journal(struct super_block *sb,
  			     struct ext4_super_block *es,
  			     unsigned long journal_devnum)
  {
  	journal_t *journal;
  	unsigned int journal_inum = le32_to_cpu(es->s_journal_inum);
  	dev_t journal_dev;
  	int err = 0;
  	int really_read_only;
  
  	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
  
  	if (journal_devnum &&
  	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
  		ext4_msg(sb, KERN_INFO, "external journal device major/minor "
  			"numbers have changed");
  		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 (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER)) {
  		if (sb->s_flags & MS_RDONLY) {
  			ext4_msg(sb, KERN_INFO, "INFO: recovery "
  					"required on readonly filesystem");
  			if (really_read_only) {
  				ext4_msg(sb, KERN_ERR, "write access "
  					"unavailable, cannot proceed");
  				return -EROFS;
  			}
  			ext4_msg(sb, KERN_INFO, "write access will "
  			       "be enabled during recovery");
  		}
  	}
  
  	if (journal_inum && journal_dev) {
  		ext4_msg(sb, KERN_ERR, "filesystem has both journal "
  		       "and inode journals!");
  		return -EINVAL;
  	}
  
  	if (journal_inum) {
  		if (!(journal = ext4_get_journal(sb, journal_inum)))
  			return -EINVAL;
  	} else {
  		if (!(journal = ext4_get_dev_journal(sb, journal_dev)))
  			return -EINVAL;
  	}
  
  	if (!(journal->j_flags & JBD2_BARRIER))
  		ext4_msg(sb, KERN_INFO, "barriers disabled");
  
  	if (!really_read_only && test_opt(sb, UPDATE_JOURNAL)) {
  		err = jbd2_journal_update_format(journal);
  		if (err)  {
  			ext4_msg(sb, KERN_ERR, "error updating journal");
  			jbd2_journal_destroy(journal);
  			return err;
  		}
  	}
  
  	if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER))
  		err = jbd2_journal_wipe(journal, !really_read_only);
  	if (!err) {
  		char *save = kmalloc(EXT4_S_ERR_LEN, GFP_KERNEL);
  		if (save)
  			memcpy(save, ((char *) es) +
  			       EXT4_S_ERR_START, EXT4_S_ERR_LEN);
  		err = jbd2_journal_load(journal);
  		if (save)
  			memcpy(((char *) es) + EXT4_S_ERR_START,
  			       save, EXT4_S_ERR_LEN);
  		kfree(save);
  	}
  
  	if (err) {
  		ext4_msg(sb, KERN_ERR, "error loading journal");
  		jbd2_journal_destroy(journal);
  		return err;
  	}
  
  	EXT4_SB(sb)->s_journal = journal;
  	ext4_clear_journal_err(sb, es);
  
  	if (!really_read_only && journal_devnum &&
  	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
  		es->s_journal_dev = cpu_to_le32(journal_devnum);
  
  		/* Make sure we flush the recovery flag to disk. */
  		ext4_commit_super(sb, 1);
  	}
  
  	return 0;
  }
  
  static int ext4_commit_super(struct super_block *sb, int sync)
  {
  	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
  	struct buffer_head *sbh = EXT4_SB(sb)->s_sbh;
  	int error = 0;
  
  	if (!sbh)
  		return error;
  	if (buffer_write_io_error(sbh)) {
  		/*
  		 * Oh, dear.  A previous attempt to write the
  		 * superblock failed.  This could happen because the
  		 * USB device was yanked out.  Or it could happen to
  		 * be a transient write error and maybe the block will
  		 * be remapped.  Nothing we can do but to retry the
  		 * write and hope for the best.
  		 */
  		ext4_msg(sb, KERN_ERR, "previous I/O error to "
  		       "superblock detected");
  		clear_buffer_write_io_error(sbh);
  		set_buffer_uptodate(sbh);
  	}
  	/*
  	 * If the file system is mounted read-only, don't update the
  	 * superblock write time.  This avoids updating the superblock
  	 * write time when we are mounting the root file system
  	 * read/only but we need to replay the journal; at that point,
  	 * for people who are east of GMT and who make their clock
  	 * tick in localtime for Windows bug-for-bug compatibility,
  	 * the clock is set in the future, and this will cause e2fsck
  	 * to complain and force a full file system check.
  	 */
  	if (!(sb->s_flags & MS_RDONLY))
  		es->s_wtime = cpu_to_le32(get_seconds());
  	if (sb->s_bdev->bd_part)
  		es->s_kbytes_written =
  			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written +
  			    ((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
  			      EXT4_SB(sb)->s_sectors_written_start) >> 1));
  	else
  		es->s_kbytes_written =
  			cpu_to_le64(EXT4_SB(sb)->s_kbytes_written);
  	ext4_free_blocks_count_set(es, percpu_counter_sum_positive(
  					   &EXT4_SB(sb)->s_freeblocks_counter));
  	es->s_free_inodes_count =
  		cpu_to_le32(percpu_counter_sum_positive(
  				&EXT4_SB(sb)->s_freeinodes_counter));
  	sb->s_dirt = 0;
  	BUFFER_TRACE(sbh, "marking dirty");
  	mark_buffer_dirty(sbh);
  	if (sync) {
  		error = sync_dirty_buffer(sbh);
  		if (error)
  			return error;
  
  		error = buffer_write_io_error(sbh);
  		if (error) {
  			ext4_msg(sb, KERN_ERR, "I/O error while writing "
  			       "superblock");
  			clear_buffer_write_io_error(sbh);
  			set_buffer_uptodate(sbh);
  		}
  	}
  	return error;
  }
  
  /*
   * 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 ext4_mark_recovery_complete(struct super_block *sb,
  					struct ext4_super_block *es)
  {
  	journal_t *journal = EXT4_SB(sb)->s_journal;
  
  	if (!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL)) {
  		BUG_ON(journal != NULL);
  		return;
  	}
  	jbd2_journal_lock_updates(journal);
  	if (jbd2_journal_flush(journal) < 0)
  		goto out;
  
  	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER) &&
  	    sb->s_flags & MS_RDONLY) {
  		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
  		ext4_commit_super(sb, 1);
  	}
  
  out:
  	jbd2_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 ext4_clear_journal_err(struct super_block *sb,
  				   struct ext4_super_block *es)
  {
  	journal_t *journal;
  	int j_errno;
  	const char *errstr;
  
  	BUG_ON(!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL));
  
  	journal = EXT4_SB(sb)->s_journal;
  
  	/*
  	 * Now check for any error status which may have been recorded in the
  	 * journal by a prior ext4_error() or ext4_abort()
  	 */
  
  	j_errno = jbd2_journal_errno(journal);
  	if (j_errno) {
  		char nbuf[16];
  
  		errstr = ext4_decode_error(sb, j_errno, nbuf);
  		ext4_warning(sb, "Filesystem error recorded "
  			     "from previous mount: %s", errstr);
  		ext4_warning(sb, "Marking fs in need of filesystem check.");
  
  		EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
  		es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
  		ext4_commit_super(sb, 1);
  
  		jbd2_journal_clear_err(journal);
  	}
  }
  
  /*
   * Force the running and committing transactions to commit,
   * and wait on the commit.
   */
  int ext4_force_commit(struct super_block *sb)
  {
  	journal_t *journal;
  	int ret = 0;
  
  	if (sb->s_flags & MS_RDONLY)
  		return 0;
  
  	journal = EXT4_SB(sb)->s_journal;
  	if (journal) {
  		vfs_check_frozen(sb, SB_FREEZE_TRANS);
  		ret = ext4_journal_force_commit(journal);
  	}
  
  	return ret;
  }
  
  static void ext4_write_super(struct super_block *sb)
  {
  	lock_super(sb);
  	ext4_commit_super(sb, 1);
  	unlock_super(sb);
  }
  
  static int ext4_sync_fs(struct super_block *sb, int wait)
  {
  	int ret = 0;
  	tid_t target;
  	struct ext4_sb_info *sbi = EXT4_SB(sb);
  
  	trace_ext4_sync_fs(sb, wait);
  	flush_workqueue(sbi->dio_unwritten_wq);
  	if (jbd2_journal_start_commit(sbi->s_journal, &target)) {
  		if (wait)
  			jbd2_log_wait_commit(sbi->s_journal, target);
  	}
  	return ret;
  }
  
  /*
   * 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.
   *
   * Note that only this function cannot bring a filesystem to be in a clean
   * state independently, because ext4 prevents a new handle from being started
   * by @sb->s_frozen, which stays in an upper layer.  It thus needs help from
   * the upper layer.
   */
  static int ext4_freeze(struct super_block *sb)
  {
  	int error = 0;
  	journal_t *journal;
  
  	if (sb->s_flags & MS_RDONLY)
  		return 0;
  
  	journal = EXT4_SB(sb)->s_journal;
  
  	/* Now we set up the journal barrier. */
  	jbd2_journal_lock_updates(journal);
  
  	/*
  	 * Don't clear the needs_recovery flag if we failed to flush
  	 * the journal.
  	 */
  	error = jbd2_journal_flush(journal);
  	if (error < 0)
  		goto out;
  
  	/* Journal blocked and flushed, clear needs_recovery flag. */
  	EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
  	error = ext4_commit_super(sb, 1);
  out:
  	/* we rely on s_frozen to stop further updates */
  	jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
  	return error;
  }
  
  /*
   * 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 int ext4_unfreeze(struct super_block *sb)
  {
  	if (sb->s_flags & MS_RDONLY)
  		return 0;
  
  	lock_super(sb);
  	/* Reset the needs_recovery flag before the fs is unlocked. */
  	EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
  	ext4_commit_super(sb, 1);
  	unlock_super(sb);
  	return 0;
  }
  
  /*
   * Structure to save mount options for ext4_remount's benefit
   */
  struct ext4_mount_options {
  	unsigned long s_mount_opt;
  	unsigned long s_mount_opt2;
  	uid_t s_resuid;
  	gid_t s_resgid;
  	unsigned long s_commit_interval;
  	u32 s_min_batch_time, s_max_batch_time;
  #ifdef CONFIG_QUOTA
  	int s_jquota_fmt;
  	char *s_qf_names[MAXQUOTAS];
  #endif
  };
  
  static int ext4_remount(struct super_block *sb, int *flags, char *data)
  {
  	struct ext4_super_block *es;
  	struct ext4_sb_info *sbi = EXT4_SB(sb);
  	ext4_fsblk_t n_blocks_count = 0;
  	unsigned long old_sb_flags;
  	struct ext4_mount_options old_opts;
  	int enable_quota = 0;
  	ext4_group_t g;
  	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
  	int err = 0;
  #ifdef CONFIG_QUOTA
  	int i;
  #endif
  	char *orig_data = kstrdup(data, GFP_KERNEL);
  
  	/* Store the original options */
  	lock_super(sb);
  	old_sb_flags = sb->s_flags;
  	old_opts.s_mount_opt = sbi->s_mount_opt;
  	old_opts.s_mount_opt2 = sbi->s_mount_opt2;
  	old_opts.s_resuid = sbi->s_resuid;
  	old_opts.s_resgid = sbi->s_resgid;
  	old_opts.s_commit_interval = sbi->s_commit_interval;
  	old_opts.s_min_batch_time = sbi->s_min_batch_time;
  	old_opts.s_max_batch_time = sbi->s_max_batch_time;
  #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
  	if (sbi->s_journal && sbi->s_journal->j_task->io_context)
  		journal_ioprio = sbi->s_journal->j_task->io_context->ioprio;
  
  	/*
  	 * Allow the "check" option to be passed as a remount option.
  	 */
  	if (!parse_options(data, sb, NULL, &journal_ioprio,
  			   &n_blocks_count, 1)) {
  		err = -EINVAL;
  		goto restore_opts;
  	}
  
  	if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED)
  		ext4_abort(sb, "Abort forced by user");
  
  	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
  		(test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
  
  	es = sbi->s_es;
  
  	if (sbi->s_journal) {
  		ext4_init_journal_params(sb, sbi->s_journal);
  		set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
  	}
  
  	if ((*flags & MS_RDONLY) != (sb->s_flags & MS_RDONLY) ||
  		n_blocks_count > ext4_blocks_count(es)) {
  		if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED) {
  			err = -EROFS;
  			goto restore_opts;
  		}
  
  		if (*flags & MS_RDONLY) {
  			err = dquot_suspend(sb, -1);
  			if (err < 0)
  				goto restore_opts;
  
  			/*
  			 * 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(EXT4_VALID_FS)) &&
  			    (sbi->s_mount_state & EXT4_VALID_FS))
  				es->s_state = cpu_to_le16(sbi->s_mount_state);
  
  			if (sbi->s_journal)
  				ext4_mark_recovery_complete(sb, es);
  		} else {
  			/* Make sure we can mount this feature set readwrite */
  			if (!ext4_feature_set_ok(sb, 0)) {
  				err = -EROFS;
  				goto restore_opts;
  			}
  			/*
  			 * Make sure the group descriptor checksums
  			 * are sane.  If they aren't, refuse to remount r/w.
  			 */
  			for (g = 0; g < sbi->s_groups_count; g++) {
  				struct ext4_group_desc *gdp =
  					ext4_get_group_desc(sb, g, NULL);
  
  				if (!ext4_group_desc_csum_verify(sbi, g, gdp)) {
  					ext4_msg(sb, KERN_ERR,
  	       "ext4_remount: Checksum for group %u failed (%u!=%u)",
  		g, le16_to_cpu(ext4_group_desc_csum(sbi, g, gdp)),
  					       le16_to_cpu(gdp->bg_checksum));
  					err = -EINVAL;
  					goto restore_opts;
  				}
  			}
  
  			/*
  			 * If we have an unprocessed orphan list hanging
  			 * around from a previously readonly bdev mount,
  			 * require a full umount/remount for now.
  			 */
  			if (es->s_last_orphan) {
  				ext4_msg(sb, KERN_WARNING, "Couldn't "
  				       "remount RDWR because of unprocessed "
  				       "orphan inode list.  Please "
  				       "umount/remount instead");
  				err = -EINVAL;
  				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.)
  			 */
  			if (sbi->s_journal)
  				ext4_clear_journal_err(sb, es);
  			sbi->s_mount_state = le16_to_cpu(es->s_state);
  			if ((err = ext4_group_extend(sb, es, n_blocks_count)))
  				goto restore_opts;
  			if (!ext4_setup_super(sb, es, 0))
  				sb->s_flags &= ~MS_RDONLY;
  			if (EXT4_HAS_INCOMPAT_FEATURE(sb,
  						     EXT4_FEATURE_INCOMPAT_MMP))
  				if (ext4_multi_mount_protect(sb,
  						le64_to_cpu(es->s_mmp_block))) {
  					err = -EROFS;
  					goto restore_opts;
  				}
  			enable_quota = 1;
  		}
  	}
  
  	/*
  	 * Reinitialize lazy itable initialization thread based on
  	 * current settings
  	 */
  	if ((sb->s_flags & MS_RDONLY) || !test_opt(sb, INIT_INODE_TABLE))
  		ext4_unregister_li_request(sb);
  	else {
  		ext4_group_t first_not_zeroed;
  		first_not_zeroed = ext4_has_uninit_itable(sb);
  		ext4_register_li_request(sb, first_not_zeroed);
  	}
  
  	ext4_setup_system_zone(sb);
  	if (sbi->s_journal == NULL && !(old_sb_flags & MS_RDONLY))
  		ext4_commit_super(sb, 1);
  
  #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
  	unlock_super(sb);
  	if (enable_quota)
  		dquot_resume(sb, -1);
  
  	ext4_msg(sb, KERN_INFO, "re-mounted. Opts: %s", orig_data);
  	kfree(orig_data);
  	return 0;
  
  restore_opts:
  	sb->s_flags = old_sb_flags;
  	sbi->s_mount_opt = old_opts.s_mount_opt;
  	sbi->s_mount_opt2 = old_opts.s_mount_opt2;
  	sbi->s_resuid = old_opts.s_resuid;
  	sbi->s_resgid = old_opts.s_resgid;
  	sbi->s_commit_interval = old_opts.s_commit_interval;
  	sbi->s_min_batch_time = old_opts.s_min_batch_time;
  	sbi->s_max_batch_time = old_opts.s_max_batch_time;
  #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
  	unlock_super(sb);
  	kfree(orig_data);
  	return err;
  }
  
  static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf)
  {
  	struct super_block *sb = dentry->d_sb;
  	struct ext4_sb_info *sbi = EXT4_SB(sb);
  	struct ext4_super_block *es = sbi->s_es;
  	u64 fsid;
  	s64 bfree;
  
  	if (test_opt(sb, MINIX_DF)) {
  		sbi->s_overhead_last = 0;
  	} else if (sbi->s_blocks_last != ext4_blocks_count(es)) {
  		ext4_group_t i, ngroups = ext4_get_groups_count(sb);
  		ext4_fsblk_t overhead = 0;
  
  		/*
  		 * Compute the overhead (FS structures).  This is constant
  		 * for a given filesystem unless the number of block groups
  		 * changes so we cache the previous value until it does.
  		 */
  
  		/*
  		 * 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 += ext4_bg_has_super(sb, i) +
  				ext4_bg_num_gdb(sb, i);
  			cond_resched();
  		}
  
  		/*
  		 * Every block group has an inode bitmap, a block
  		 * bitmap, and an inode table.
  		 */
  		overhead += ngroups * (2 + sbi->s_itb_per_group);
  		sbi->s_overhead_last = overhead;
  		smp_wmb();
  		sbi->s_blocks_last = ext4_blocks_count(es);
  	}
  
  	buf->f_type = EXT4_SUPER_MAGIC;
  	buf->f_bsize = sb->s_blocksize;
  	buf->f_blocks = ext4_blocks_count(es) - sbi->s_overhead_last;
  	bfree = percpu_counter_sum_positive(&sbi->s_freeblocks_counter) -
  		       percpu_counter_sum_positive(&sbi->s_dirtyblocks_counter);
  	/* prevent underflow in case that few free space is available */
  	buf->f_bfree = max_t(s64, bfree, 0);
  	buf->f_bavail = buf->f_bfree - ext4_r_blocks_count(es);
  	if (buf->f_bfree < ext4_r_blocks_count(es))
  		buf->f_bavail = 0;
  	buf->f_files = le32_to_cpu(es->s_inodes_count);
  	buf->f_ffree = percpu_counter_sum_positive(&sbi->s_freeinodes_counter);
  	buf->f_namelen = EXT4_NAME_LEN;
  	fsid = le64_to_cpup((void *)es->s_uuid) ^
  	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
  	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
  	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
  
  	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
   * ext4_create()                     quota_sync()
   *   jbd2_journal_start()                  write_dquot()
   *   dquot_initialize()                         down(dqio_mutex)
   *     down(dqio_mutex)                    jbd2_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 ext4_write_dquot(struct dquot *dquot)
  {
  	int ret, err;
  	handle_t *handle;
  	struct inode *inode;
  
  	inode = dquot_to_inode(dquot);
  	handle = ext4_journal_start(inode,
  				    EXT4_QUOTA_TRANS_BLOCKS(dquot->dq_sb));
  	if (IS_ERR(handle))
  		return PTR_ERR(handle);
  	ret = dquot_commit(dquot);
  	err = ext4_journal_stop(handle);
  	if (!ret)
  		ret = err;
  	return ret;
  }
  
  static int ext4_acquire_dquot(struct dquot *dquot)
  {
  	int ret, err;
  	handle_t *handle;
  
  	handle = ext4_journal_start(dquot_to_inode(dquot),
  				    EXT4_QUOTA_INIT_BLOCKS(dquot->dq_sb));
  	if (IS_ERR(handle))
  		return PTR_ERR(handle);
  	ret = dquot_acquire(dquot);
  	err = ext4_journal_stop(handle);
  	if (!ret)
  		ret = err;
  	return ret;
  }
  
  static int ext4_release_dquot(struct dquot *dquot)
  {
  	int ret, err;
  	handle_t *handle;
  
  	handle = ext4_journal_start(dquot_to_inode(dquot),
  				    EXT4_QUOTA_DEL_BLOCKS(dquot->dq_sb));
  	if (IS_ERR(handle)) {
  		/* Release dquot anyway to avoid endless cycle in dqput() */
  		dquot_release(dquot);
  		return PTR_ERR(handle);
  	}
  	ret = dquot_release(dquot);
  	err = ext4_journal_stop(handle);
  	if (!ret)
  		ret = err;
  	return ret;
  }
  
  static int ext4_mark_dquot_dirty(struct dquot *dquot)
  {
  	/* Are we journaling quotas? */
  	if (EXT4_SB(dquot->dq_sb)->s_qf_names[USRQUOTA] ||
  	    EXT4_SB(dquot->dq_sb)->s_qf_names[GRPQUOTA]) {
  		dquot_mark_dquot_dirty(dquot);
  		return ext4_write_dquot(dquot);
  	} else {
  		return dquot_mark_dquot_dirty(dquot);
  	}
  }
  
  static int ext4_write_info(struct super_block *sb, int type)
  {
  	int ret, err;
  	handle_t *handle;
  
  	/* Data block + inode block */
  	handle = ext4_journal_start(sb->s_root->d_inode, 2);
  	if (IS_ERR(handle))
  		return PTR_ERR(handle);
  	ret = dquot_commit_info(sb, type);
  	err = ext4_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 ext4_quota_on_mount(struct super_block *sb, int type)
  {
  	return dquot_quota_on_mount(sb, EXT4_SB(sb)->s_qf_names[type],
  					EXT4_SB(sb)->s_jquota_fmt, type);
  }
  
  /*
   * Standard function to be called on quota_on
   */
  static int ext4_quota_on(struct super_block *sb, int type, int format_id,
  			 struct path *path)
  {
  	int err;
  
  	if (!test_opt(sb, QUOTA))
  		return -EINVAL;
  
  	/* Quotafile not on the same filesystem? */
  	if (path->mnt->mnt_sb != sb)
  		return -EXDEV;
  	/* Journaling quota? */
  	if (EXT4_SB(sb)->s_qf_names[type]) {
  		/* Quotafile not in fs root? */
  		if (path->dentry->d_parent != sb->s_root)
  			ext4_msg(sb, KERN_WARNING,
  				"Quota file not on filesystem root. "
  				"Journaled quota will not work");
  	}
  
  	/*
  	 * When we journal data on quota file, we have to flush journal to see
  	 * all updates to the file when we bypass pagecache...
  	 */
  	if (EXT4_SB(sb)->s_journal &&
  	    ext4_should_journal_data(path->dentry->d_inode)) {
  		/*
  		 * We don't need to lock updates but journal_flush() could
  		 * otherwise be livelocked...
  		 */
  		jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);
  		err = jbd2_journal_flush(EXT4_SB(sb)->s_journal);
  		jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
  		if (err)
  			return err;
  	}
  
  	return dquot_quota_on(sb, type, format_id, path);
  }
  
  static int ext4_quota_off(struct super_block *sb, int type)
  {
  	struct inode *inode = sb_dqopt(sb)->files[type];
  	handle_t *handle;
  
  	/* Force all delayed allocation blocks to be allocated.
  	 * Caller already holds s_umount sem */
  	if (test_opt(sb, DELALLOC))
  		sync_filesystem(sb);
  
  	if (!inode)
  		goto out;
  
  	/* Update modification times of quota files when userspace can
  	 * start looking at them */
  	handle = ext4_journal_start(inode, 1);
  	if (IS_ERR(handle))
  		goto out;
  	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
  	ext4_mark_inode_dirty(handle, inode);
  	ext4_journal_stop(handle);
  
  out:
  	return dquot_quota_off(sb, type);
  }
  
  /* 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 ext4_quota_read(struct super_block *sb, int type, char *data,
  			       size_t len, loff_t off)
  {
  	struct inode *inode = sb_dqopt(sb)->files[type];
  	ext4_lblk_t blk = off >> EXT4_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 = ext4_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 ext4_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];
  	ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
  	int err = 0;
  	int offset = off & (sb->s_blocksize - 1);
  	struct buffer_head *bh;
  	handle_t *handle = journal_current_handle();
  
  	if (EXT4_SB(sb)->s_journal && !handle) {
  		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
  			" cancelled because transaction is not started",
  			(unsigned long long)off, (unsigned long long)len);
  		return -EIO;
  	}
  	/*
  	 * Since we account only one data block in transaction credits,
  	 * then it is impossible to cross a block boundary.
  	 */
  	if (sb->s_blocksize - offset < len) {
  		ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
  			" cancelled because not block aligned",
  			(unsigned long long)off, (unsigned long long)len);
  		return -EIO;
  	}
  
  	mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
  	bh = ext4_bread(handle, inode, blk, 1, &err);
  	if (!bh)
  		goto out;
  	err = ext4_journal_get_write_access(handle, bh);
  	if (err) {
  		brelse(bh);
  		goto out;
  	}
  	lock_buffer(bh);
  	memcpy(bh->b_data+offset, data, len);
  	flush_dcache_page(bh->b_page);
  	unlock_buffer(bh);
  	err = ext4_handle_dirty_metadata(handle, NULL, bh);
  	brelse(bh);
  out:
  	if (err) {
  		mutex_unlock(&inode->i_mutex);
  		return err;
  	}
  	if (inode->i_size < off + len) {
  		i_size_write(inode, off + len);
  		EXT4_I(inode)->i_disksize = inode->i_size;
  		ext4_mark_inode_dirty(handle, inode);
  	}
  	mutex_unlock(&inode->i_mutex);
  	return len;
  }
  
  #endif
  
  static struct dentry *ext4_mount(struct file_system_type *fs_type, int flags,
  		       const char *dev_name, void *data)
  {
  	return mount_bdev(fs_type, flags, dev_name, data, ext4_fill_super);
  }
  
  #if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
  static inline void register_as_ext2(void)
  {
  	int err = register_filesystem(&ext2_fs_type);
  	if (err)
  		printk(KERN_WARNING
  		       "EXT4-fs: Unable to register as ext2 (%d)\n", err);
  }
  
  static inline void unregister_as_ext2(void)
  {
  	unregister_filesystem(&ext2_fs_type);
  }
  
  static inline int ext2_feature_set_ok(struct super_block *sb)
  {
  	if (EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP))
  		return 0;
  	if (sb->s_flags & MS_RDONLY)
  		return 1;
  	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))
  		return 0;
  	return 1;
  }
  MODULE_ALIAS("ext2");
  #else
  static inline void register_as_ext2(void) { }
  static inline void unregister_as_ext2(void) { }
  static inline int ext2_feature_set_ok(struct super_block *sb) { return 0; }
  #endif
  
  #if !defined(CONFIG_EXT3_FS) && !defined(CONFIG_EXT3_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
  static inline void register_as_ext3(void)
  {
  	int err = register_filesystem(&ext3_fs_type);
  	if (err)
  		printk(KERN_WARNING
  		       "EXT4-fs: Unable to register as ext3 (%d)\n", err);
  }
  
  static inline void unregister_as_ext3(void)
  {
  	unregister_filesystem(&ext3_fs_type);
  }
  
  static inline int ext3_feature_set_ok(struct super_block *sb)
  {
  	if (EXT4_HAS_INCOMPAT_FEATURE(sb, ~EXT3_FEATURE_INCOMPAT_SUPP))
  		return 0;
  	if (!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_HAS_JOURNAL))
  		return 0;
  	if (sb->s_flags & MS_RDONLY)
  		return 1;
  	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, ~EXT3_FEATURE_RO_COMPAT_SUPP))
  		return 0;
  	return 1;
  }
  MODULE_ALIAS("ext3");
  #else
  static inline void register_as_ext3(void) { }
  static inline void unregister_as_ext3(void) { }
  static inline int ext3_feature_set_ok(struct super_block *sb) { return 0; }
  #endif
  
  static struct file_system_type ext4_fs_type = {
  	.owner		= THIS_MODULE,
  	.name		= "ext4",
  	.mount		= ext4_mount,
  	.kill_sb	= kill_block_super,
  	.fs_flags	= FS_REQUIRES_DEV,
  };
  
  static int __init ext4_init_feat_adverts(void)
  {
  	struct ext4_features *ef;
  	int ret = -ENOMEM;
  
  	ef = kzalloc(sizeof(struct ext4_features), GFP_KERNEL);
  	if (!ef)
  		goto out;
  
  	ef->f_kobj.kset = ext4_kset;
  	init_completion(&ef->f_kobj_unregister);
  	ret = kobject_init_and_add(&ef->f_kobj, &ext4_feat_ktype, NULL,
  				   "features");
  	if (ret) {
  		kfree(ef);
  		goto out;
  	}
  
  	ext4_feat = ef;
  	ret = 0;
  out:
  	return ret;
  }
  
  static void ext4_exit_feat_adverts(void)
  {
  	kobject_put(&ext4_feat->f_kobj);
  	wait_for_completion(&ext4_feat->f_kobj_unregister);
  	kfree(ext4_feat);
  }
  
  /* Shared across all ext4 file systems */
  wait_queue_head_t ext4__ioend_wq[EXT4_WQ_HASH_SZ];
  struct mutex ext4__aio_mutex[EXT4_WQ_HASH_SZ];
  
  static int __init ext4_init_fs(void)
  {
  	int i, err;
  
  	ext4_check_flag_values();
  
  	for (i = 0; i < EXT4_WQ_HASH_SZ; i++) {
  		mutex_init(&ext4__aio_mutex[i]);
  		init_waitqueue_head(&ext4__ioend_wq[i]);
  	}
  
  	err = ext4_init_pageio();
  	if (err)
  		return err;
  	err = ext4_init_system_zone();
  	if (err)
  		goto out7;
  	ext4_kset = kset_create_and_add("ext4", NULL, fs_kobj);
  	if (!ext4_kset)
  		goto out6;
  	ext4_proc_root = proc_mkdir("fs/ext4", NULL);
  	if (!ext4_proc_root)
  		goto out5;
  
  	err = ext4_init_feat_adverts();
  	if (err)
  		goto out4;
  
  	err = ext4_init_mballoc();
  	if (err)
  		goto out3;
  
  	err = ext4_init_xattr();
  	if (err)
  		goto out2;
  	err = init_inodecache();
  	if (err)
  		goto out1;
  	register_as_ext3();
  	register_as_ext2();
  	err = register_filesystem(&ext4_fs_type);
  	if (err)
  		goto out;
  
  	ext4_li_info = NULL;
  	mutex_init(&ext4_li_mtx);
  	return 0;
  out:
  	unregister_as_ext2();
  	unregister_as_ext3();
  	destroy_inodecache();
  out1:
  	ext4_exit_xattr();
  out2:
  	ext4_exit_mballoc();
  out3:
  	ext4_exit_feat_adverts();
  out4:
  	remove_proc_entry("fs/ext4", NULL);
  out5:
  	kset_unregister(ext4_kset);
  out6:
  	ext4_exit_system_zone();
  out7:
  	ext4_exit_pageio();
  	return err;
  }
  
  static void __exit ext4_exit_fs(void)
  {
  	ext4_destroy_lazyinit_thread();
  	unregister_as_ext2();
  	unregister_as_ext3();
  	unregister_filesystem(&ext4_fs_type);
  	destroy_inodecache();
  	ext4_exit_xattr();
  	ext4_exit_mballoc();
  	ext4_exit_feat_adverts();
  	remove_proc_entry("fs/ext4", NULL);
  	kset_unregister(ext4_kset);
  	ext4_exit_system_zone();
  	ext4_exit_pageio();
  }
  
  MODULE_AUTHOR("Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others");
  MODULE_DESCRIPTION("Fourth Extended Filesystem");
  MODULE_LICENSE("GPL");
  module_init(ext4_init_fs)
  module_exit(ext4_exit_fs)
  