/*
 *  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 <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;
struct ext4_lazy_init *ext4_li_info;
struct mutex ext4_li_mtx;
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 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_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;

        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.
 */
handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks)
{
        journal_t *journal;

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

        vfs_check_frozen(sb, SB_FREEZE_TRANS);
        /* Special case here: if the journal has aborted behind our
         * backs (eg. EIO in the commit thread), then we still need to
         * take the FS itself readonly cleanly. */
        journal = EXT4_SB(sb)->s_journal;
        if (journal) {
                if (is_journal_aborted(journal)) {
                        ext4_abort(sb, "Detected aborted journal");
                        return ERR_PTR(-EROFS);
                }
                return jbd2_journal_start(journal, nblocks);
        }
        return ext4_get_nojournal();
}

/*
 * 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);
}


/* 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 beween 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);
        }
        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);
        INIT_LIST_HEAD(&inode->i_dentry);
        kmem_cache_free(ext4_inode_cachep, EXT4_I(inode));
}

static void ext4_destroy_inode(struct inode *inode)
{
        ext4_ioend_wait(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) &&

                !(def_mount_opts & EXT4_DEFM_XATTR_USER))
                seq_puts(seq, ",user_xattr");
        if (!test_opt(sb, XATTR_USER) &&
            (def_mount_opts & EXT4_DEFM_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, ",mblk_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_inode_table");
        else if (sbi->s_li_wait_mult)
                seq_printf(seq, ",init_inode_table=%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 = {
#ifdef CONFIG_QUOTA
        .get_reserved_space = ext4_get_reserved_space,
#endif
        .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_inode_table, Opt_noinit_inode_table,
};

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_inode_table, "init_itable=%u"},
        {Opt_init_inode_table, "init_itable"},
        {Opt_noinit_inode_table, "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 = 0;
                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 (!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_inode_table:
                        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_inode_table:
                        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);

        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;
        int groups_per_flex = 0;
        size_t size;
        int i;

        sbi->s_log_groups_per_flex = sbi->s_es->s_log_groups_per_flex;
        groups_per_flex = 1 << sbi->s_log_groups_per_flex;

        if (groups_per_flex < 2) {
                sbi->s_log_groups_per_flex = 0;
                return 1;
        }

        /* 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);
                atomic_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;
        }

        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.
 *
 * 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 */
        res = 1LL << 32;
        res <<= blkbits;
        res -= 1;

        /* 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 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 (!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;
                }
        }
        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 */
}

static void ext4_lazyinode_timeout(unsigned long data)
{
        struct task_struct *p = (struct task_struct *)data;
        wake_up_process(p);
}

/* 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;
                        if (elr->lr_sbi->s_li_wait_mult)
                                timeout *= elr->lr_sbi->s_li_wait_mult;
                        else
                                timeout *= 20;
                        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 tructure. 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)
{
        struct ext4_li_request *elr = EXT4_SB(sb)->s_li_request;

        if (!ext4_li_info)
                return;

        mutex_lock(&ext4_li_info->li_list_mtx);
        ext4_remove_li_request(elr);
        mutex_unlock(&ext4_li_info->li_list_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;
        DEFINE_WAIT(wait);

        BUG_ON(NULL == eli);

        eli->li_timer.data = (unsigned long)current;
        eli->li_timer.function = ext4_lazyinode_timeout;

        eli->li_task = current;
        wake_up(&eli->li_wait_task);

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();

                if ((time_after_eq(jiffies, next_wakeup)) ||
                    (MAX_JIFFY_OFFSET == next_wakeup)) {
                        cond_resched();
                        continue;
                }

                eli->li_timer.expires = next_wakeup;
                add_timer(&eli->li_timer);
                prepare_to_wait(&eli->li_wait_daemon, &wait,
                                TASK_INTERRUPTIBLE);
                if (time_before(jiffies, next_wakeup))
                        schedule();
                finish_wait(&eli->li_wait_daemon, &wait);
                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);
        del_timer_sync(&ext4_li_info->li_timer);
        eli->li_task = NULL;
        wake_up(&eli->li_wait_task);

        kfree(ext4_li_info);
        ext4_lazyinit_task = NULL;
        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();
                del_timer_sync(&ext4_li_info->li_timer);
                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;

        wait_event(ext4_li_info->li_wait_task, ext4_li_info->li_task != NULL);
        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;

        eli->li_task = NULL;
        INIT_LIST_HEAD(&eli->li_request_list);
        mutex_init(&eli->li_list_mtx);

        init_waitqueue_head(&eli->li_wait_daemon);
        init_waitqueue_head(&eli->li_wait_task);
        init_timer(&eli->li_timer);
        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)
                return 0;

        if (first_not_zeroed == ngroups ||
            (sb->s_flags & MS_RDONLY) ||
            !test_opt(sb, INIT_INODE_TABLE)) {
                sbi->s_li_request = NULL;
                return 0;
        }

        if (first_not_zeroed == ngroups) {
                sbi->s_li_request = NULL;
                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;

        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);
}