fs/ext4/super.c

/*
 *  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_extents.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

void *ext4_kvmalloc(size_t size, gfp_t flags)
{
	void *ret;

	ret = kmalloc(size, flags);
	if (!ret)
		ret = __vmalloc(size, flags, PAGE_KERNEL);
	return ret;
}

void *ext4_kvzalloc(size_t size, gfp_t flags)
{
	void *ret;

	ret = kzalloc(size, flags);
	if (!ret)
		ret = __vmalloc(size, flags | __GFP_ZERO, PAGE_KERNEL);
	return ret;
}

void ext4_kvfree(void *ptr)
{
	if (is_vmalloc_addr(ptr))
		vfree(ptr);
	else
		kfree(ptr);

}

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_group_clusters(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_group_clusters_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;

	BUG_ON(ref_cnt >= EXT4_NOJOURNAL_MAX_REF_COUNT);

	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;

	BUG_ON(ref_cnt == 0);

	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;

	trace_ext4_journal_start(sb, nblocks, _RET_IP_);
	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);

	BUG_ON(!ext4_handle_valid(handle));

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

	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);
}

/*
 * The del_gendisk() function uninitializes the disk-specific data
 * structures, including the bdi structure, without telling anyone
 * else.  Once this happens, any attempt to call mark_buffer_dirty()
 * (for example, by ext4_commit_super), will cause a kernel OOPS.
 * This is a kludge to prevent these oops until we can put in a proper
 * hook in del_gendisk() to inform the VFS and file system layers.
 */
static int block_device_ejected(struct super_block *sb)
{
	struct inode *bd_inode = sb->s_bdev->bd_inode;
	struct backing_dev_info *bdi = bd_inode->i_mapping->backing_dev_info;

	return bdi->dev == NULL;
}


/* 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);

	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]);
	ext4_kvfree(sbi->s_group_desc);
	ext4_kvfree(sbi->s_flex_groups);
	percpu_counter_destroy(&sbi->s_freeclusters_counter);
	percpu_counter_destroy(&sbi->s_freeinodes_counter);
	percpu_counter_destroy(&sbi->s_dirs_counter);
	percpu_counter_destroy(&sbi->s_dirtyclusters_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;
	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);
	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 dentry *root)
{
	int def_errors;
	unsigned long def_mount_opts;
	struct super_block *sb = root->d_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");
#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_max_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:
			ext4_msg(sb, KERN_WARNING,
				 "Ignoring deprecated oldalloc option");
			break;
		case Opt_orlov:
			ext4_msg(sb, KERN_WARNING,
				 "Ignoring deprecated orlov option");
			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 (!sbi->s_journal)
					ext4_msg(sb, KERN_WARNING, "Remounting file system with no journal so ignoring journalled data option");
				else 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);
			clear_opt2(sb, EXPLICIT_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);
			set_opt2(sb, EXPLICIT_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)
		goto done;
	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);
done:
	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 = ext4_kvzalloc(size, GFP_KERNEL);
	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);
		atomic_add(ext4_free_group_clusters(sb, gdp),
			   &sbi->s_flex_groups[flex_group].free_clusters);
		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_C2B(sbi, ext4_count_free_clusters(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);
			ext4_truncate(inode);
			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);
	int ret;

	if (sbi->s_stripe && sbi->s_stripe <= sbi->s_blocks_per_group)
		ret = sbi->s_stripe;
	else if (stripe_width <= sbi->s_blocks_per_group)
		ret = stripe_width;
	else if (stride <= sbi->s_blocks_per_group)
		ret = stride;
	else
		ret = 0;

	/*
	 * If the stripe width is 1, this makes no sense and
	 * we set it to 0 to turn off stripe handling code.
	 */
	if (ret <= 1)
		ret = 0;

	return ret;
}

/* 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) EXT4_C2B(sbi,
			percpu_counter_sum(&sbi->s_dirtyclusters_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 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_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(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;
		}
	}
	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_BIGALLOC) &&
	    !EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
		ext4_msg(sb, KERN_ERR,
			 "Can't support bigalloc feature without "
			 "extents feature\n");
		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);

		try_to_freeze();

		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;