blk-mq: do not do head insertions post-pre-flush commands

[linux.git] / fs / ext4 / super.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/fs/ext4/super.c
 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card ([email protected])
 * 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 ([email protected]), 1995
 */

#include <linux/module.h>
#include <linux/string.h>
#include <linux/fs.h>
#include <linux/time.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/backing-dev.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/ctype.h>
#include <linux/log2.h>
#include <linux/crc16.h>
#include <linux/dax.h>
#include <linux/uaccess.h>
#include <linux/iversion.h>
#include <linux/unicode.h>
#include <linux/part_stat.h>
#include <linux/kthread.h>
#include <linux/freezer.h>
#include <linux/fsnotify.h>
#include <linux/fs_context.h>
#include <linux/fs_parser.h>

#include "ext4.h"
#include "ext4_extents.h"       /* Needed for trace points definition */
#include "ext4_jbd2.h"
#include "xattr.h"
#include "acl.h"
#include "mballoc.h"
#include "fsmap.h"

#define CREATE_TRACE_POINTS
#include <trace/events/ext4.h>

static struct ext4_lazy_init *ext4_li_info;
static DEFINE_MUTEX(ext4_li_mtx);
static struct ratelimit_state ext4_mount_msg_ratelimit;

static int ext4_load_journal(struct super_block *, struct ext4_super_block *,
                             unsigned long journal_devnum);
static int ext4_show_options(struct seq_file *seq, struct dentry *root);
static void ext4_update_super(struct super_block *sb);
static int ext4_commit_super(struct super_block *sb);
static int ext4_mark_recovery_complete(struct super_block *sb,
                                        struct ext4_super_block *es);
static int 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 int ext4_statfs(struct dentry *dentry, struct kstatfs *buf);
static int ext4_unfreeze(struct super_block *sb);
static int ext4_freeze(struct super_block *sb);
static inline int ext2_feature_set_ok(struct super_block *sb);
static inline int ext3_feature_set_ok(struct super_block *sb);
static void ext4_destroy_lazyinit_thread(void);
static void ext4_unregister_li_request(struct super_block *sb);
static void ext4_clear_request_list(void);
static struct inode *ext4_get_journal_inode(struct super_block *sb,
                                            unsigned int journal_inum);
static int ext4_validate_options(struct fs_context *fc);
static int ext4_check_opt_consistency(struct fs_context *fc,
                                      struct super_block *sb);
static void ext4_apply_options(struct fs_context *fc, struct super_block *sb);
static int ext4_parse_param(struct fs_context *fc, struct fs_parameter *param);
static int ext4_get_tree(struct fs_context *fc);
static int ext4_reconfigure(struct fs_context *fc);
static void ext4_fc_free(struct fs_context *fc);
static int ext4_init_fs_context(struct fs_context *fc);
static const struct fs_parameter_spec ext4_param_specs[];

/*
 * Lock ordering
 *
 * page fault path:
 * mmap_lock -> sb_start_pagefault -> invalidate_lock (r) -> transaction start
 *   -> page lock -> i_data_sem (rw)
 *
 * buffered write path:
 * sb_start_write -> i_mutex -> mmap_lock
 * sb_start_write -> i_mutex -> transaction start -> page lock ->
 *   i_data_sem (rw)
 *
 * truncate:
 * sb_start_write -> i_mutex -> invalidate_lock (w) -> i_mmap_rwsem (w) ->
 *   page lock
 * sb_start_write -> i_mutex -> invalidate_lock (w) -> transaction start ->
 *   i_data_sem (rw)
 *
 * direct IO:
 * sb_start_write -> i_mutex -> mmap_lock
 * sb_start_write -> i_mutex -> transaction start -> i_data_sem (rw)
 *
 * writepages:
 * transaction start -> page lock(s) -> i_data_sem (rw)
 */

static const struct fs_context_operations ext4_context_ops = {
        .parse_param    = ext4_parse_param,
        .get_tree       = ext4_get_tree,
        .reconfigure    = ext4_reconfigure,
        .free           = ext4_fc_free,
};


#if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT2)
static struct file_system_type ext2_fs_type = {
        .owner                  = THIS_MODULE,
        .name                   = "ext2",
        .init_fs_context        = ext4_init_fs_context,
        .parameters             = ext4_param_specs,
        .kill_sb                = kill_block_super,
        .fs_flags               = FS_REQUIRES_DEV,
};
MODULE_ALIAS_FS("ext2");
MODULE_ALIAS("ext2");
#define IS_EXT2_SB(sb) ((sb)->s_bdev->bd_holder == &ext2_fs_type)
#else
#define IS_EXT2_SB(sb) (0)
#endif


static struct file_system_type ext3_fs_type = {
        .owner                  = THIS_MODULE,
        .name                   = "ext3",
        .init_fs_context        = ext4_init_fs_context,
        .parameters             = ext4_param_specs,
        .kill_sb                = kill_block_super,
        .fs_flags               = FS_REQUIRES_DEV,
};
MODULE_ALIAS_FS("ext3");
MODULE_ALIAS("ext3");
#define IS_EXT3_SB(sb) ((sb)->s_bdev->bd_holder == &ext3_fs_type)


static inline void __ext4_read_bh(struct buffer_head *bh, blk_opf_t op_flags,
                                  bh_end_io_t *end_io)
{
        /*
         * buffer's verified bit is no longer valid after reading from
         * disk again due to write out error, clear it to make sure we
         * recheck the buffer contents.
         */
        clear_buffer_verified(bh);

        bh->b_end_io = end_io ? end_io : end_buffer_read_sync;
        get_bh(bh);
        submit_bh(REQ_OP_READ | op_flags, bh);
}

void ext4_read_bh_nowait(struct buffer_head *bh, blk_opf_t op_flags,
                         bh_end_io_t *end_io)
{
        BUG_ON(!buffer_locked(bh));

        if (ext4_buffer_uptodate(bh)) {
                unlock_buffer(bh);
                return;
        }
        __ext4_read_bh(bh, op_flags, end_io);
}

int ext4_read_bh(struct buffer_head *bh, blk_opf_t op_flags, bh_end_io_t *end_io)
{
        BUG_ON(!buffer_locked(bh));

        if (ext4_buffer_uptodate(bh)) {
                unlock_buffer(bh);
                return 0;
        }

        __ext4_read_bh(bh, op_flags, end_io);

        wait_on_buffer(bh);
        if (buffer_uptodate(bh))
                return 0;
        return -EIO;
}

int ext4_read_bh_lock(struct buffer_head *bh, blk_opf_t op_flags, bool wait)
{
        lock_buffer(bh);
        if (!wait) {
                ext4_read_bh_nowait(bh, op_flags, NULL);
                return 0;
        }
        return ext4_read_bh(bh, op_flags, NULL);
}

/*
 * This works like __bread_gfp() except it uses ERR_PTR for error
 * returns.  Currently with sb_bread it's impossible to distinguish
 * between ENOMEM and EIO situations (since both result in a NULL
 * return.
 */
static struct buffer_head *__ext4_sb_bread_gfp(struct super_block *sb,
                                               sector_t block,
                                               blk_opf_t op_flags, gfp_t gfp)
{
        struct buffer_head *bh;
        int ret;

        bh = sb_getblk_gfp(sb, block, gfp);
        if (bh == NULL)
                return ERR_PTR(-ENOMEM);
        if (ext4_buffer_uptodate(bh))
                return bh;

        ret = ext4_read_bh_lock(bh, REQ_META | op_flags, true);
        if (ret) {
                put_bh(bh);
                return ERR_PTR(ret);
        }
        return bh;
}

struct buffer_head *ext4_sb_bread(struct super_block *sb, sector_t block,
                                   blk_opf_t op_flags)
{
        return __ext4_sb_bread_gfp(sb, block, op_flags, __GFP_MOVABLE);
}

struct buffer_head *ext4_sb_bread_unmovable(struct super_block *sb,
                                            sector_t block)
{
        return __ext4_sb_bread_gfp(sb, block, 0, 0);
}

void ext4_sb_breadahead_unmovable(struct super_block *sb, sector_t block)
{
        struct buffer_head *bh = sb_getblk_gfp(sb, block, 0);

        if (likely(bh)) {
                if (trylock_buffer(bh))
                        ext4_read_bh_nowait(bh, REQ_RAHEAD, NULL);
                brelse(bh);
        }
}

static int ext4_verify_csum_type(struct super_block *sb,
                                 struct ext4_super_block *es)
{
        if (!ext4_has_feature_metadata_csum(sb))
                return 1;

        return es->s_checksum_type == EXT4_CRC32C_CHKSUM;
}

__le32 ext4_superblock_csum(struct super_block *sb,
                            struct ext4_super_block *es)
{
        struct ext4_sb_info *sbi = EXT4_SB(sb);
        int offset = offsetof(struct ext4_super_block, s_checksum);
        __u32 csum;

        csum = ext4_chksum(sbi, ~0, (char *)es, offset);

        return cpu_to_le32(csum);
}

static int ext4_superblock_csum_verify(struct super_block *sb,
                                       struct ext4_super_block *es)
{
        if (!ext4_has_metadata_csum(sb))
                return 1;

        return es->s_checksum == ext4_superblock_csum(sb, es);
}

void ext4_superblock_csum_set(struct super_block *sb)
{
        struct ext4_super_block *es = EXT4_SB(sb)->s_es;

        if (!ext4_has_metadata_csum(sb))
                return;

        es->s_checksum = ext4_superblock_csum(sb, es);
}

ext4_fsblk_t ext4_block_bitmap(struct super_block *sb,
                               struct ext4_group_desc *bg)
{
        return le32_to_cpu(bg->bg_block_bitmap_lo) |
                (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
                 (ext4_fsblk_t)le32_to_cpu(bg->bg_block_bitmap_hi) << 32 : 0);
}

ext4_fsblk_t ext4_inode_bitmap(struct super_block *sb,
                               struct ext4_group_desc *bg)
{
        return le32_to_cpu(bg->bg_inode_bitmap_lo) |
                (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
                 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_bitmap_hi) << 32 : 0);
}

ext4_fsblk_t ext4_inode_table(struct super_block *sb,
                              struct ext4_group_desc *bg)
{
        return le32_to_cpu(bg->bg_inode_table_lo) |
                (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
                 (ext4_fsblk_t)le32_to_cpu(bg->bg_inode_table_hi) << 32 : 0);
}

__u32 ext4_free_group_clusters(struct super_block *sb,
                               struct ext4_group_desc *bg)
{
        return le16_to_cpu(bg->bg_free_blocks_count_lo) |
                (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
                 (__u32)le16_to_cpu(bg->bg_free_blocks_count_hi) << 16 : 0);
}

__u32 ext4_free_inodes_count(struct super_block *sb,
                              struct ext4_group_desc *bg)
{
        return le16_to_cpu(bg->bg_free_inodes_count_lo) |
                (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
                 (__u32)le16_to_cpu(bg->bg_free_inodes_count_hi) << 16 : 0);
}

__u32 ext4_used_dirs_count(struct super_block *sb,
                              struct ext4_group_desc *bg)
{
        return le16_to_cpu(bg->bg_used_dirs_count_lo) |
                (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
                 (__u32)le16_to_cpu(bg->bg_used_dirs_count_hi) << 16 : 0);
}

__u32 ext4_itable_unused_count(struct super_block *sb,
                              struct ext4_group_desc *bg)
{
        return le16_to_cpu(bg->bg_itable_unused_lo) |
                (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT ?
                 (__u32)le16_to_cpu(bg->bg_itable_unused_hi) << 16 : 0);
}

void ext4_block_bitmap_set(struct super_block *sb,
                           struct ext4_group_desc *bg, ext4_fsblk_t blk)
{
        bg->bg_block_bitmap_lo = cpu_to_le32((u32)blk);
        if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
                bg->bg_block_bitmap_hi = cpu_to_le32(blk >> 32);
}

void ext4_inode_bitmap_set(struct super_block *sb,
                           struct ext4_group_desc *bg, ext4_fsblk_t blk)
{
        bg->bg_inode_bitmap_lo  = cpu_to_le32((u32)blk);
        if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
                bg->bg_inode_bitmap_hi = cpu_to_le32(blk >> 32);
}

void ext4_inode_table_set(struct super_block *sb,
                          struct ext4_group_desc *bg, ext4_fsblk_t blk)
{
        bg->bg_inode_table_lo = cpu_to_le32((u32)blk);
        if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
                bg->bg_inode_table_hi = cpu_to_le32(blk >> 32);
}

void ext4_free_group_clusters_set(struct super_block *sb,
                                  struct ext4_group_desc *bg, __u32 count)
{
        bg->bg_free_blocks_count_lo = cpu_to_le16((__u16)count);
        if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
                bg->bg_free_blocks_count_hi = cpu_to_le16(count >> 16);
}

void ext4_free_inodes_set(struct super_block *sb,
                          struct ext4_group_desc *bg, __u32 count)
{
        bg->bg_free_inodes_count_lo = cpu_to_le16((__u16)count);
        if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
                bg->bg_free_inodes_count_hi = cpu_to_le16(count >> 16);
}

void ext4_used_dirs_set(struct super_block *sb,
                          struct ext4_group_desc *bg, __u32 count)
{
        bg->bg_used_dirs_count_lo = cpu_to_le16((__u16)count);
        if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
                bg->bg_used_dirs_count_hi = cpu_to_le16(count >> 16);
}

void ext4_itable_unused_set(struct super_block *sb,
                          struct ext4_group_desc *bg, __u32 count)
{
        bg->bg_itable_unused_lo = cpu_to_le16((__u16)count);
        if (EXT4_DESC_SIZE(sb) >= EXT4_MIN_DESC_SIZE_64BIT)
                bg->bg_itable_unused_hi = cpu_to_le16(count >> 16);
}

static void __ext4_update_tstamp(__le32 *lo, __u8 *hi, time64_t now)
{
        now = clamp_val(now, 0, (1ull << 40) - 1);

        *lo = cpu_to_le32(lower_32_bits(now));
        *hi = upper_32_bits(now);
}

static time64_t __ext4_get_tstamp(__le32 *lo, __u8 *hi)
{
        return ((time64_t)(*hi) << 32) + le32_to_cpu(*lo);
}
#define ext4_update_tstamp(es, tstamp) \
        __ext4_update_tstamp(&(es)->tstamp, &(es)->tstamp ## _hi, \
                             ktime_get_real_seconds())
#define ext4_get_tstamp(es, tstamp) \
        __ext4_get_tstamp(&(es)->tstamp, &(es)->tstamp ## _hi)

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

        return bdi->dev == NULL;
}

static void ext4_journal_commit_callback(journal_t *journal, transaction_t *txn)
{
        struct super_block              *sb = journal->j_private;
        struct ext4_sb_info             *sbi = EXT4_SB(sb);
        int                             error = is_journal_aborted(journal);
        struct ext4_journal_cb_entry    *jce;

        BUG_ON(txn->t_state == T_FINISHED);

        ext4_process_freed_data(sb, txn->t_tid);

        spin_lock(&sbi->s_md_lock);
        while (!list_empty(&txn->t_private_list)) {
                jce = list_entry(txn->t_private_list.next,
                                 struct ext4_journal_cb_entry, jce_list);
                list_del_init(&jce->jce_list);
                spin_unlock(&sbi->s_md_lock);
                jce->jce_func(sb, jce, error);
                spin_lock(&sbi->s_md_lock);
        }
        spin_unlock(&sbi->s_md_lock);
}

/*
 * This writepage callback for write_cache_pages()
 * takes care of a few cases after page cleaning.
 *
 * write_cache_pages() already checks for dirty pages
 * and calls clear_page_dirty_for_io(), which we want,
 * to write protect the pages.
 *
 * However, we may have to redirty a page (see below.)
 */
static int ext4_journalled_writepage_callback(struct folio *folio,
                                              struct writeback_control *wbc,
                                              void *data)
{
        transaction_t *transaction = (transaction_t *) data;
        struct buffer_head *bh, *head;
        struct journal_head *jh;

        bh = head = folio_buffers(folio);
        do {
                /*
                 * We have to redirty a page in these cases:
                 * 1) If buffer is dirty, it means the page was dirty because it
                 * contains a buffer that needs checkpointing. So the dirty bit
                 * needs to be preserved so that checkpointing writes the buffer
                 * properly.
                 * 2) If buffer is not part of the committing transaction
                 * (we may have just accidentally come across this buffer because
                 * inode range tracking is not exact) or if the currently running
                 * transaction already contains this buffer as well, dirty bit
                 * needs to be preserved so that the buffer gets writeprotected
                 * properly on running transaction's commit.
                 */
                jh = bh2jh(bh);
                if (buffer_dirty(bh) ||
                    (jh && (jh->b_transaction != transaction ||
                            jh->b_next_transaction))) {
                        folio_redirty_for_writepage(wbc, folio);
                        goto out;
                }
        } while ((bh = bh->b_this_page) != head);

out:
        return AOP_WRITEPAGE_ACTIVATE;
}

static int ext4_journalled_submit_inode_data_buffers(struct jbd2_inode *jinode)
{
        struct address_space *mapping = jinode->i_vfs_inode->i_mapping;
        struct writeback_control wbc = {
                .sync_mode =  WB_SYNC_ALL,
                .nr_to_write = LONG_MAX,
                .range_start = jinode->i_dirty_start,
                .range_end = jinode->i_dirty_end,
        };

        return write_cache_pages(mapping, &wbc,
                                 ext4_journalled_writepage_callback,
                                 jinode->i_transaction);
}

static int ext4_journal_submit_inode_data_buffers(struct jbd2_inode *jinode)
{
        int ret;

        if (ext4_should_journal_data(jinode->i_vfs_inode))
                ret = ext4_journalled_submit_inode_data_buffers(jinode);
        else
                ret = ext4_normal_submit_inode_data_buffers(jinode);
        return ret;
}

static int ext4_journal_finish_inode_data_buffers(struct jbd2_inode *jinode)
{
        int ret = 0;

        if (!ext4_should_journal_data(jinode->i_vfs_inode))
                ret = jbd2_journal_finish_inode_data_buffers(jinode);

        return ret;
}

static bool system_going_down(void)
{
        return system_state == SYSTEM_HALT || system_state == SYSTEM_POWER_OFF
                || system_state == SYSTEM_RESTART;
}

struct ext4_err_translation {
        int code;
        int errno;
};

#define EXT4_ERR_TRANSLATE(err) { .code = EXT4_ERR_##err, .errno = err }

static struct ext4_err_translation err_translation[] = {
        EXT4_ERR_TRANSLATE(EIO),
        EXT4_ERR_TRANSLATE(ENOMEM),
        EXT4_ERR_TRANSLATE(EFSBADCRC),
        EXT4_ERR_TRANSLATE(EFSCORRUPTED),
        EXT4_ERR_TRANSLATE(ENOSPC),
        EXT4_ERR_TRANSLATE(ENOKEY),
        EXT4_ERR_TRANSLATE(EROFS),
        EXT4_ERR_TRANSLATE(EFBIG),
        EXT4_ERR_TRANSLATE(EEXIST),
        EXT4_ERR_TRANSLATE(ERANGE),
        EXT4_ERR_TRANSLATE(EOVERFLOW),
        EXT4_ERR_TRANSLATE(EBUSY),
        EXT4_ERR_TRANSLATE(ENOTDIR),
        EXT4_ERR_TRANSLATE(ENOTEMPTY),
        EXT4_ERR_TRANSLATE(ESHUTDOWN),
        EXT4_ERR_TRANSLATE(EFAULT),
};

static int ext4_errno_to_code(int errno)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(err_translation); i++)
                if (err_translation[i].errno == errno)
                        return err_translation[i].code;
        return EXT4_ERR_UNKNOWN;
}

static void save_error_info(struct super_block *sb, int error,
                            __u32 ino, __u64 block,
                            const char *func, unsigned int line)
{
        struct ext4_sb_info *sbi = EXT4_SB(sb);

        /* We default to EFSCORRUPTED error... */
        if (error == 0)
                error = EFSCORRUPTED;

        spin_lock(&sbi->s_error_lock);
        sbi->s_add_error_count++;
        sbi->s_last_error_code = error;
        sbi->s_last_error_line = line;
        sbi->s_last_error_ino = ino;
        sbi->s_last_error_block = block;
        sbi->s_last_error_func = func;
        sbi->s_last_error_time = ktime_get_real_seconds();
        if (!sbi->s_first_error_time) {
                sbi->s_first_error_code = error;
                sbi->s_first_error_line = line;
                sbi->s_first_error_ino = ino;
                sbi->s_first_error_block = block;
                sbi->s_first_error_func = func;
                sbi->s_first_error_time = sbi->s_last_error_time;
        }
        spin_unlock(&sbi->s_error_lock);
}

/* 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.
 *
 * If force_ro is set, 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. This is
 * used to deal with unrecoverable failures such as journal IO errors or ENOMEM
 * at a critical moment in log management.
 */
static void ext4_handle_error(struct super_block *sb, bool force_ro, int error,
                              __u32 ino, __u64 block,
                              const char *func, unsigned int line)
{
        journal_t *journal = EXT4_SB(sb)->s_journal;
        bool continue_fs = !force_ro && test_opt(sb, ERRORS_CONT);

        EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
        if (test_opt(sb, WARN_ON_ERROR))
                WARN_ON_ONCE(1);

        if (!continue_fs && !sb_rdonly(sb)) {
                ext4_set_mount_flag(sb, EXT4_MF_FS_ABORTED);
                if (journal)
                        jbd2_journal_abort(journal, -EIO);
        }

        if (!bdev_read_only(sb->s_bdev)) {
                save_error_info(sb, error, ino, block, func, line);
                /*
                 * In case the fs should keep running, we need to writeout
                 * superblock through the journal. Due to lock ordering
                 * constraints, it may not be safe to do it right here so we
                 * defer superblock flushing to a workqueue.
                 */
                if (continue_fs && journal)
                        schedule_work(&EXT4_SB(sb)->s_error_work);
                else
                        ext4_commit_super(sb);
        }

        /*
         * We force ERRORS_RO behavior when system is rebooting. Otherwise we
         * could panic during 'reboot -f' as the underlying device got already
         * disabled.
         */
        if (test_opt(sb, ERRORS_PANIC) && !system_going_down()) {
                panic("EXT4-fs (device %s): panic forced after error\n",
                        sb->s_id);
        }

        if (sb_rdonly(sb) || continue_fs)
                return;

        ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
        /*
         * Make sure updated value of ->s_mount_flags will be visible before
         * ->s_flags update
         */
        smp_wmb();
        sb->s_flags |= SB_RDONLY;
}

static void flush_stashed_error_work(struct work_struct *work)
{
        struct ext4_sb_info *sbi = container_of(work, struct ext4_sb_info,
                                                s_error_work);
        journal_t *journal = sbi->s_journal;
        handle_t *handle;

        /*
         * If the journal is still running, we have to write out superblock
         * through the journal to avoid collisions of other journalled sb
         * updates.
         *
         * We use directly jbd2 functions here to avoid recursing back into
         * ext4 error handling code during handling of previous errors.
         */
        if (!sb_rdonly(sbi->s_sb) && journal) {
                struct buffer_head *sbh = sbi->s_sbh;
                handle = jbd2_journal_start(journal, 1);
                if (IS_ERR(handle))
                        goto write_directly;
                if (jbd2_journal_get_write_access(handle, sbh)) {
                        jbd2_journal_stop(handle);
                        goto write_directly;
                }
                ext4_update_super(sbi->s_sb);
                if (buffer_write_io_error(sbh) || !buffer_uptodate(sbh)) {
                        ext4_msg(sbi->s_sb, KERN_ERR, "previous I/O error to "
                                 "superblock detected");
                        clear_buffer_write_io_error(sbh);
                        set_buffer_uptodate(sbh);
                }

                if (jbd2_journal_dirty_metadata(handle, sbh)) {
                        jbd2_journal_stop(handle);
                        goto write_directly;
                }
                jbd2_journal_stop(handle);
                ext4_notify_error_sysfs(sbi);
                return;
        }
write_directly:
        /*
         * Write through journal failed. Write sb directly to get error info
         * out and hope for the best.
         */
        ext4_commit_super(sbi->s_sb);
        ext4_notify_error_sysfs(sbi);
}

#define ext4_error_ratelimit(sb)                                        \
                ___ratelimit(&(EXT4_SB(sb)->s_err_ratelimit_state),     \
                             "EXT4-fs error")

void __ext4_error(struct super_block *sb, const char *function,
                  unsigned int line, bool force_ro, int error, __u64 block,
                  const char *fmt, ...)
{
        struct va_format vaf;
        va_list args;

        if (unlikely(ext4_forced_shutdown(EXT4_SB(sb))))
                return;

        trace_ext4_error(sb, function, line);
        if (ext4_error_ratelimit(sb)) {
                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);
        }
        fsnotify_sb_error(sb, NULL, error ? error : EFSCORRUPTED);

        ext4_handle_error(sb, force_ro, error, 0, block, function, line);
}

void __ext4_error_inode(struct inode *inode, const char *function,
                        unsigned int line, ext4_fsblk_t block, int error,
                        const char *fmt, ...)
{
        va_list args;
        struct va_format vaf;

        if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
                return;

        trace_ext4_error(inode->i_sb, function, line);
        if (ext4_error_ratelimit(inode->i_sb)) {
                va_start(args, fmt);
                vaf.fmt = fmt;
                vaf.va = &args;
                if (block)
                        printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: "
                               "inode #%lu: block %llu: comm %s: %pV\n",
                               inode->i_sb->s_id, function, line, inode->i_ino,
                               block, current->comm, &vaf);
                else
                        printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: "
                               "inode #%lu: comm %s: %pV\n",
                               inode->i_sb->s_id, function, line, inode->i_ino,
                               current->comm, &vaf);
                va_end(args);
        }
        fsnotify_sb_error(inode->i_sb, inode, error ? error : EFSCORRUPTED);

        ext4_handle_error(inode->i_sb, false, error, inode->i_ino, block,
                          function, line);
}

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 inode *inode = file_inode(file);
        char pathname[80], *path;

        if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
                return;

        trace_ext4_error(inode->i_sb, function, line);
        if (ext4_error_ratelimit(inode->i_sb)) {
                path = file_path(file, pathname, sizeof(pathname));
                if (IS_ERR(path))
                        path = "(unknown)";
                va_start(args, fmt);
                vaf.fmt = fmt;
                vaf.va = &args;
                if (block)
                        printk(KERN_CRIT
                               "EXT4-fs error (device %s): %s:%d: inode #%lu: "
                               "block %llu: comm %s: path %s: %pV\n",
                               inode->i_sb->s_id, function, line, inode->i_ino,
                               block, current->comm, path, &vaf);
                else
                        printk(KERN_CRIT
                               "EXT4-fs error (device %s): %s:%d: inode #%lu: "
                               "comm %s: path %s: %pV\n",
                               inode->i_sb->s_id, function, line, inode->i_ino,
                               current->comm, path, &vaf);
                va_end(args);
        }
        fsnotify_sb_error(inode->i_sb, inode, EFSCORRUPTED);

        ext4_handle_error(inode->i_sb, false, EFSCORRUPTED, inode->i_ino, block,
                          function, line);
}

const char *ext4_decode_error(struct super_block *sb, int errno,
                              char nbuf[16])
{
        char *errstr = NULL;

        switch (errno) {
        case -EFSCORRUPTED:
                errstr = "Corrupt filesystem";
                break;
        case -EFSBADCRC:
                errstr = "Filesystem failed CRC";
                break;
        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;

        if (unlikely(ext4_forced_shutdown(EXT4_SB(sb))))
                return;

        /* 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_rdonly(sb))
                return;

        if (ext4_error_ratelimit(sb)) {
                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);
        }
        fsnotify_sb_error(sb, NULL, errno ? errno : EFSCORRUPTED);

        ext4_handle_error(sb, false, -errno, 0, 0, function, line);
}

void __ext4_msg(struct super_block *sb,
                const char *prefix, const char *fmt, ...)
{
        struct va_format vaf;
        va_list args;

        if (sb) {
                atomic_inc(&EXT4_SB(sb)->s_msg_count);
                if (!___ratelimit(&(EXT4_SB(sb)->s_msg_ratelimit_state),
                                  "EXT4-fs"))
                        return;
        }

        va_start(args, fmt);
        vaf.fmt = fmt;
        vaf.va = &args;
        if (sb)
                printk("%sEXT4-fs (%s): %pV\n", prefix, sb->s_id, &vaf);
        else
                printk("%sEXT4-fs: %pV\n", prefix, &vaf);
        va_end(args);
}

static int ext4_warning_ratelimit(struct super_block *sb)
{
        atomic_inc(&EXT4_SB(sb)->s_warning_count);
        return ___ratelimit(&(EXT4_SB(sb)->s_warning_ratelimit_state),
                            "EXT4-fs warning");
}

void __ext4_warning(struct super_block *sb, const char *function,
                    unsigned int line, const char *fmt, ...)
{
        struct va_format vaf;
        va_list args;

        if (!ext4_warning_ratelimit(sb))
                return;

        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_warning_inode(const struct inode *inode, const char *function,
                          unsigned int line, const char *fmt, ...)
{
        struct va_format vaf;
        va_list args;

        if (!ext4_warning_ratelimit(inode->i_sb))
                return;

        va_start(args, fmt);
        vaf.fmt = fmt;
        vaf.va = &args;
        printk(KERN_WARNING "EXT4-fs warning (device %s): %s:%d: "
               "inode #%lu: comm %s: %pV\n", inode->i_sb->s_id,
               function, line, inode->i_ino, current->comm, &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;

        if (unlikely(ext4_forced_shutdown(EXT4_SB(sb))))
                return;

        trace_ext4_error(sb, function, line);
        if (ext4_error_ratelimit(sb)) {
                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)) {
                if (test_opt(sb, WARN_ON_ERROR))
                        WARN_ON_ONCE(1);
                EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
                if (!bdev_read_only(sb->s_bdev)) {
                        save_error_info(sb, EFSCORRUPTED, ino, block, function,
                                        line);
                        schedule_work(&EXT4_SB(sb)->s_error_work);
                }
                return;
        }
        ext4_unlock_group(sb, grp);
        ext4_handle_error(sb, false, EFSCORRUPTED, ino, block, function, line);
        /*
         * We only get here in the ERRORS_RO case; relocking the group
         * may be dangerous, but nothing bad will happen since the
         * filesystem will have already been marked read/only and the
         * journal has been aborted.  We return 1 as a hint to callers
         * who might what to use the return value from
         * ext4_grp_locked_error() to distinguish between the
         * ERRORS_CONT and ERRORS_RO case, and perhaps return more
         * aggressively from the ext4 function in question, with a
         * more appropriate error code.
         */
        ext4_lock_group(sb, grp);
        return;
}

void ext4_mark_group_bitmap_corrupted(struct super_block *sb,
                                     ext4_group_t group,
                                     unsigned int flags)
{
        struct ext4_sb_info *sbi = EXT4_SB(sb);
        struct ext4_group_info *grp = ext4_get_group_info(sb, group);
        struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group, NULL);
        int ret;

        if (!grp || !gdp)
                return;
        if (flags & EXT4_GROUP_INFO_BBITMAP_CORRUPT) {
                ret = ext4_test_and_set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT,
                                            &grp->bb_state);
                if (!ret)
                        percpu_counter_sub(&sbi->s_freeclusters_counter,
                                           grp->bb_free);
        }

        if (flags & EXT4_GROUP_INFO_IBITMAP_CORRUPT) {
                ret = ext4_test_and_set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT,
                                            &grp->bb_state);
                if (!ret && gdp) {
                        int count;

                        count = ext4_free_inodes_count(sb, gdp);
                        percpu_counter_sub(&sbi->s_freeinodes_counter,
                                           count);
                }
        }
}

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;

        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 unknown-block(%u,%u) %ld",
                 MAJOR(dev), MINOR(dev), PTR_ERR(bdev));
        return NULL;
}

/*
 * Release the journal device
 */
static void ext4_blkdev_put(struct block_device *bdev)
{
        blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
}

static void ext4_blkdev_remove(struct ext4_sb_info *sbi)
{
        struct block_device *bdev;
        bdev = sbi->s_journal_bdev;
        if (bdev) {
                ext4_blkdev_put(bdev);
                sbi->s_journal_bdev = NULL;
        }
}

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));
        }
}

#ifdef CONFIG_QUOTA
static int ext4_quota_off(struct super_block *sb, int type);

static inline void ext4_quota_off_umount(struct super_block *sb)
{
        int type;

        /* Use our quota_off function to clear inode flags etc. */
        for (type = 0; type < EXT4_MAXQUOTAS; type++)
                ext4_quota_off(sb, type);
}

/*
 * This is a helper function which is used in the mount/remount
 * codepaths (which holds s_umount) to fetch the quota file name.
 */
static inline char *get_qf_name(struct super_block *sb,
                                struct ext4_sb_info *sbi,
                                int type)
{
        return rcu_dereference_protected(sbi->s_qf_names[type],
                                         lockdep_is_held(&sb->s_umount));
}
#else
static inline void ext4_quota_off_umount(struct super_block *sb)
{
}
#endif

static int ext4_percpu_param_init(struct ext4_sb_info *sbi)
{
        ext4_fsblk_t block;
        int err;

        block = ext4_count_free_clusters(sbi->s_sb);
        ext4_free_blocks_count_set(sbi->s_es, EXT4_C2B(sbi, block));
        err = percpu_counter_init(&sbi->s_freeclusters_counter, block,
                                  GFP_KERNEL);
        if (!err) {
                unsigned long freei = ext4_count_free_inodes(sbi->s_sb);
                sbi->s_es->s_free_inodes_count = cpu_to_le32(freei);
                err = percpu_counter_init(&sbi->s_freeinodes_counter, freei,
                                          GFP_KERNEL);
        }
        if (!err)
                err = percpu_counter_init(&sbi->s_dirs_counter,
                                          ext4_count_dirs(sbi->s_sb), GFP_KERNEL);
        if (!err)
                err = percpu_counter_init(&sbi->s_dirtyclusters_counter, 0,
                                          GFP_KERNEL);
        if (!err)
                err = percpu_counter_init(&sbi->s_sra_exceeded_retry_limit, 0,
                                          GFP_KERNEL);
        if (!err)
                err = percpu_init_rwsem(&sbi->s_writepages_rwsem);

        if (err)
                ext4_msg(sbi->s_sb, KERN_ERR, "insufficient memory");

        return err;
}

static void ext4_percpu_param_destroy(struct ext4_sb_info *sbi)
{
        percpu_counter_destroy(&sbi->s_freeclusters_counter);
        percpu_counter_destroy(&sbi->s_freeinodes_counter);
        percpu_counter_destroy(&sbi->s_dirs_counter);
        percpu_counter_destroy(&sbi->s_dirtyclusters_counter);
        percpu_counter_destroy(&sbi->s_sra_exceeded_retry_limit);
        percpu_free_rwsem(&sbi->s_writepages_rwsem);
}

static void ext4_group_desc_free(struct ext4_sb_info *sbi)
{
        struct buffer_head **group_desc;
        int i;

        rcu_read_lock();
        group_desc = rcu_dereference(sbi->s_group_desc);
        for (i = 0; i < sbi->s_gdb_count; i++)
                brelse(group_desc[i]);
        kvfree(group_desc);
        rcu_read_unlock();
}

static void ext4_flex_groups_free(struct ext4_sb_info *sbi)
{
        struct flex_groups **flex_groups;
        int i;

        rcu_read_lock();
        flex_groups = rcu_dereference(sbi->s_flex_groups);
        if (flex_groups) {
                for (i = 0; i < sbi->s_flex_groups_allocated; i++)
                        kvfree(flex_groups[i]);
                kvfree(flex_groups);
        }
        rcu_read_unlock();
}

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 aborted = 0;
        int err;

        /*
         * Unregister sysfs before destroying jbd2 journal.
         * Since we could still access attr_journal_task attribute via sysfs
         * path which could have sbi->s_journal->j_task as NULL
         * Unregister sysfs before flush sbi->s_error_work.
         * Since user may read /proc/fs/ext4/xx/mb_groups during umount, If
         * read metadata verify failed then will queue error work.
         * flush_stashed_error_work will call start_this_handle may trigger
         * BUG_ON.
         */
        ext4_unregister_sysfs(sb);

        if (___ratelimit(&ext4_mount_msg_ratelimit, "EXT4-fs unmount"))
                ext4_msg(sb, KERN_INFO, "unmounting filesystem %pU.",
                         &sb->s_uuid);

        ext4_unregister_li_request(sb);
        ext4_quota_off_umount(sb);

        flush_work(&sbi->s_error_work);
        destroy_workqueue(sbi->rsv_conversion_wq);
        ext4_release_orphan_info(sb);

        if (sbi->s_journal) {
                aborted = is_journal_aborted(sbi->s_journal);
                err = jbd2_journal_destroy(sbi->s_journal);
                sbi->s_journal = NULL;
                if ((err < 0) && !aborted) {
                        ext4_abort(sb, -err, "Couldn't clean up the journal");
                }
        }

        ext4_es_unregister_shrinker(sbi);
        timer_shutdown_sync(&sbi->s_err_report);
        ext4_release_system_zone(sb);
        ext4_mb_release(sb);
        ext4_ext_release(sb);

        if (!sb_rdonly(sb) && !aborted) {
                ext4_clear_feature_journal_needs_recovery(sb);
                ext4_clear_feature_orphan_present(sb);
                es->s_state = cpu_to_le16(sbi->s_mount_state);
        }
        if (!sb_rdonly(sb))
                ext4_commit_super(sb);

        ext4_group_desc_free(sbi);
        ext4_flex_groups_free(sbi);
        ext4_percpu_param_destroy(sbi);
#ifdef CONFIG_QUOTA
        for (int i = 0; i < EXT4_MAXQUOTAS; i++)
                kfree(get_qf_name(sb, sbi, 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);
        ASSERT(list_empty(&sbi->s_orphan));

        sync_blockdev(sb->s_bdev);
        invalidate_bdev(sb->s_bdev);
        if (sbi->s_journal_bdev && sbi->s_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->s_journal_bdev);
                invalidate_bdev(sbi->s_journal_bdev);
                ext4_blkdev_remove(sbi);
        }

        ext4_xattr_destroy_cache(sbi->s_ea_inode_cache);
        sbi->s_ea_inode_cache = NULL;

        ext4_xattr_destroy_cache(sbi->s_ea_block_cache);
        sbi->s_ea_block_cache = NULL;

        ext4_stop_mmpd(sbi);

        brelse(sbi->s_sbh);
        sb->s_fs_info = NULL;
        /*
         * Now that we are completely done shutting down the
         * superblock, we need to actually destroy the kobject.
         */
        kobject_put(&sbi->s_kobj);
        wait_for_completion(&sbi->s_kobj_unregister);
        if (sbi->s_chksum_driver)
                crypto_free_shash(sbi->s_chksum_driver);
        kfree(sbi->s_blockgroup_lock);
        fs_put_dax(sbi->s_daxdev, NULL);
        fscrypt_free_dummy_policy(&sbi->s_dummy_enc_policy);
#if IS_ENABLED(CONFIG_UNICODE)
        utf8_unload(sb->s_encoding);
#endif
        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 = alloc_inode_sb(sb, ext4_inode_cachep, GFP_NOFS);
        if (!ei)
                return NULL;

        inode_set_iversion(&ei->vfs_inode, 1);
        ei->i_flags = 0;
        spin_lock_init(&ei->i_raw_lock);
        ei->i_prealloc_node = RB_ROOT;
        atomic_set(&ei->i_prealloc_active, 0);
        rwlock_init(&ei->i_prealloc_lock);
        ext4_es_init_tree(&ei->i_es_tree);
        rwlock_init(&ei->i_es_lock);
        INIT_LIST_HEAD(&ei->i_es_list);
        ei->i_es_all_nr = 0;
        ei->i_es_shk_nr = 0;
        ei->i_es_shrink_lblk = 0;
        ei->i_reserved_data_blocks = 0;
        spin_lock_init(&(ei->i_block_reservation_lock));
        ext4_init_pending_tree(&ei->i_pending_tree);
#ifdef CONFIG_QUOTA
        ei->i_reserved_quota = 0;
        memset(&ei->i_dquot, 0, sizeof(ei->i_dquot));
#endif
        ei->jinode = NULL;
        INIT_LIST_HEAD(&ei->i_rsv_conversion_list);
        spin_lock_init(&ei->i_completed_io_lock);
        ei->i_sync_tid = 0;
        ei->i_datasync_tid = 0;
        atomic_set(&ei->i_unwritten, 0);
        INIT_WORK(&ei->i_rsv_conversion_work, ext4_end_io_rsv_work);
        ext4_fc_init_inode(&ei->vfs_inode);
        mutex_init(&ei->i_fc_lock);
        return &ei->vfs_inode;
}

static int ext4_drop_inode(struct inode *inode)
{
        int drop = generic_drop_inode(inode);

        if (!drop)
                drop = fscrypt_drop_inode(inode);

        trace_ext4_drop_inode(inode, drop);
        return drop;
}

static void ext4_free_in_core_inode(struct inode *inode)
{
        fscrypt_free_inode(inode);
        if (!list_empty(&(EXT4_I(inode)->i_fc_list))) {
                pr_warn("%s: inode %ld still in fc list",
                        __func__, inode->i_ino);
        }
        kmem_cache_free(ext4_inode_cachep, EXT4_I(inode));
}

static void ext4_destroy_inode(struct inode *inode)
{
        if (!list_empty(&(EXT4_I(inode)->i_orphan))) {
                ext4_msg(inode->i_sb, KERN_ERR,
                         "Inode %lu (%p): orphan list check failed!",
                         inode->i_ino, EXT4_I(inode));
                print_hex_dump(KERN_INFO, "", DUMP_PREFIX_ADDRESS, 16, 4,
                                EXT4_I(inode), sizeof(struct ext4_inode_info),
                                true);
                dump_stack();
        }

        if (EXT4_I(inode)->i_reserved_data_blocks)
                ext4_msg(inode->i_sb, KERN_ERR,
                         "Inode %lu (%p): i_reserved_data_blocks (%u) not cleared!",
                         inode->i_ino, EXT4_I(inode),
                         EXT4_I(inode)->i_reserved_data_blocks);
}

static void init_once(void *foo)
{
        struct ext4_inode_info *ei = foo;

        INIT_LIST_HEAD(&ei->i_orphan);
        init_rwsem(&ei->xattr_sem);
        init_rwsem(&ei->i_data_sem);
        inode_init_once(&ei->vfs_inode);
        ext4_fc_init_inode(&ei->vfs_inode);
}

static int __init init_inodecache(void)
{
        ext4_inode_cachep = kmem_cache_create_usercopy("ext4_inode_cache",
                                sizeof(struct ext4_inode_info), 0,
                                (SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
                                        SLAB_ACCOUNT),
                                offsetof(struct ext4_inode_info, i_data),
                                sizeof_field(struct ext4_inode_info, i_data),
                                init_once);
        if (ext4_inode_cachep == NULL)
                return -ENOMEM;
        return 0;
}

static void destroy_inodecache(void)
{
        /*
         * Make sure all delayed rcu free inodes are flushed before we
         * destroy cache.
         */
        rcu_barrier();
        kmem_cache_destroy(ext4_inode_cachep);
}

void ext4_clear_inode(struct inode *inode)
{
        ext4_fc_del(inode);
        invalidate_inode_buffers(inode);
        clear_inode(inode);
        ext4_discard_preallocations(inode, 0);
        ext4_es_remove_extent(inode, 0, EXT_MAX_BLOCKS);
        dquot_drop(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;
        }
        fscrypt_put_encryption_info(inode);
        fsverity_cleanup_inode(inode);
}

static struct inode *ext4_nfs_get_inode(struct super_block *sb,
                                        u64 ino, u32 generation)
{
        struct inode *inode;

        /*
         * Currently we don't know the generation for parent directory, so
         * a generation of 0 means "accept any"
         */
        inode = ext4_iget(sb, ino, EXT4_IGET_HANDLE);
        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);
}

static int ext4_nfs_commit_metadata(struct inode *inode)
{
        struct writeback_control wbc = {
                .sync_mode = WB_SYNC_ALL
        };

        trace_ext4_nfs_commit_metadata(inode);
        return ext4_write_inode(inode, &wbc);
}

#ifdef CONFIG_QUOTA
static const char * const quotatypes[] = INITQFNAMES;
#define QTYPE2NAME(t) (quotatypes[t])

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,
                         const struct path *path);
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 int ext4_quota_enable(struct super_block *sb, int type, int format_id,
                             unsigned int flags);

static struct dquot **ext4_get_dquots(struct inode *inode)
{
        return EXT4_I(inode)->i_dquot;
}

static const struct dquot_operations ext4_quota_operations = {
        .get_reserved_space     = ext4_get_reserved_space,
        .write_dquot            = ext4_write_dquot,
        .acquire_dquot          = ext4_acquire_dquot,
        .release_dquot          = ext4_release_dquot,
        .mark_dirty             = ext4_mark_dquot_dirty,
        .write_info             = ext4_write_info,
        .alloc_dquot            = dquot_alloc,
        .destroy_dquot          = dquot_destroy,
        .get_projid             = ext4_get_projid,
        .get_inode_usage        = ext4_get_inode_usage,
        .get_next_id            = dquot_get_next_id,
};

static const struct quotactl_ops ext4_qctl_operations = {
        .quota_on       = ext4_quota_on,
        .quota_off      = ext4_quota_off,
        .quota_sync     = dquot_quota_sync,
        .get_state      = dquot_get_state,
        .set_info       = dquot_set_dqinfo,
        .get_dqblk      = dquot_get_dqblk,
        .set_dqblk      = dquot_set_dqblk,
        .get_nextdqblk  = dquot_get_next_dqblk,
};
#endif

static const struct super_operations ext4_sops = {
        .alloc_inode    = ext4_alloc_inode,
        .free_inode     = ext4_free_in_core_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,
        .show_options   = ext4_show_options,
#ifdef CONFIG_QUOTA
        .quota_read     = ext4_quota_read,
        .quota_write    = ext4_quota_write,
        .get_dquots     = ext4_get_dquots,
#endif
};

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,
        .commit_metadata = ext4_nfs_commit_metadata,
};

enum {
        Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
        Opt_resgid, Opt_resuid, Opt_sb,
        Opt_nouid32, Opt_debug, Opt_removed,
        Opt_user_xattr, Opt_acl,
        Opt_auto_da_alloc, Opt_noauto_da_alloc, Opt_noload,
        Opt_commit, Opt_min_batch_time, Opt_max_batch_time, Opt_journal_dev,
        Opt_journal_path, 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_test_dummy_encryption,
        Opt_inlinecrypt,
        Opt_usrjquota, Opt_grpjquota, Opt_quota,
        Opt_noquota, Opt_barrier, Opt_nobarrier, Opt_err,
        Opt_usrquota, Opt_grpquota, Opt_prjquota,
        Opt_dax, Opt_dax_always, Opt_dax_inode, Opt_dax_never,
        Opt_stripe, Opt_delalloc, Opt_nodelalloc, Opt_warn_on_error,
        Opt_nowarn_on_error, Opt_mblk_io_submit, Opt_debug_want_extra_isize,
        Opt_nomblk_io_submit, Opt_block_validity, Opt_noblock_validity,
        Opt_inode_readahead_blks, Opt_journal_ioprio,
        Opt_dioread_nolock, Opt_dioread_lock,
        Opt_discard, Opt_nodiscard, Opt_init_itable, Opt_noinit_itable,
        Opt_max_dir_size_kb, Opt_nojournal_checksum, Opt_nombcache,
        Opt_no_prefetch_block_bitmaps, Opt_mb_optimize_scan,
        Opt_errors, Opt_data, Opt_data_err, Opt_jqfmt, Opt_dax_type,
#ifdef CONFIG_EXT4_DEBUG
        Opt_fc_debug_max_replay, Opt_fc_debug_force
#endif
};

static const struct constant_table ext4_param_errors[] = {
        {"continue",    EXT4_MOUNT_ERRORS_CONT},
        {"panic",       EXT4_MOUNT_ERRORS_PANIC},
        {"remount-ro",  EXT4_MOUNT_ERRORS_RO},
        {}
};

static const struct constant_table ext4_param_data[] = {
        {"journal",     EXT4_MOUNT_JOURNAL_DATA},
        {"ordered",     EXT4_MOUNT_ORDERED_DATA},
        {"writeback",   EXT4_MOUNT_WRITEBACK_DATA},
        {}
};

static const struct constant_table ext4_param_data_err[] = {
        {"abort",       Opt_data_err_abort},
        {"ignore",      Opt_data_err_ignore},
        {}
};

static const struct constant_table ext4_param_jqfmt[] = {
        {"vfsold",      QFMT_VFS_OLD},
        {"vfsv0",       QFMT_VFS_V0},
        {"vfsv1",       QFMT_VFS_V1},
        {}
};

static const struct constant_table ext4_param_dax[] = {
        {"always",      Opt_dax_always},
        {"inode",       Opt_dax_inode},
        {"never",       Opt_dax_never},
        {}
};

/* String parameter that allows empty argument */
#define fsparam_string_empty(NAME, OPT) \
        __fsparam(fs_param_is_string, NAME, OPT, fs_param_can_be_empty, NULL)

/*
 * Mount option specification
 * We don't use fsparam_flag_no because of the way we set the
 * options and the way we show them in _ext4_show_options(). To
 * keep the changes to a minimum, let's keep the negative options
 * separate for now.
 */
static const struct fs_parameter_spec ext4_param_specs[] = {
        fsparam_flag    ("bsddf",               Opt_bsd_df),
        fsparam_flag    ("minixdf",             Opt_minix_df),
        fsparam_flag    ("grpid",               Opt_grpid),
        fsparam_flag    ("bsdgroups",           Opt_grpid),
        fsparam_flag    ("nogrpid",             Opt_nogrpid),
        fsparam_flag    ("sysvgroups",          Opt_nogrpid),
        fsparam_u32     ("resgid",              Opt_resgid),
        fsparam_u32     ("resuid",              Opt_resuid),
        fsparam_u32     ("sb",                  Opt_sb),
        fsparam_enum    ("errors",              Opt_errors, ext4_param_errors),
        fsparam_flag    ("nouid32",             Opt_nouid32),
        fsparam_flag    ("debug",               Opt_debug),
        fsparam_flag    ("oldalloc",            Opt_removed),
        fsparam_flag    ("orlov",               Opt_removed),
        fsparam_flag    ("user_xattr",          Opt_user_xattr),
        fsparam_flag    ("acl",                 Opt_acl),
        fsparam_flag    ("norecovery",          Opt_noload),
        fsparam_flag    ("noload",              Opt_noload),
        fsparam_flag    ("bh",                  Opt_removed),
        fsparam_flag    ("nobh",                Opt_removed),
        fsparam_u32     ("commit",              Opt_commit),
        fsparam_u32     ("min_batch_time",      Opt_min_batch_time),
        fsparam_u32     ("max_batch_time",      Opt_max_batch_time),
        fsparam_u32     ("journal_dev",         Opt_journal_dev),
        fsparam_bdev    ("journal_path",        Opt_journal_path),
        fsparam_flag    ("journal_checksum",    Opt_journal_checksum),
        fsparam_flag    ("nojournal_checksum",  Opt_nojournal_checksum),
        fsparam_flag    ("journal_async_commit",Opt_journal_async_commit),
        fsparam_flag    ("abort",               Opt_abort),
        fsparam_enum    ("data",                Opt_data, ext4_param_data),
        fsparam_enum    ("data_err",            Opt_data_err,
                                                ext4_param_data_err),
        fsparam_string_empty
                        ("usrjquota",           Opt_usrjquota),
        fsparam_string_empty
                        ("grpjquota",           Opt_grpjquota),
        fsparam_enum    ("jqfmt",               Opt_jqfmt, ext4_param_jqfmt),
        fsparam_flag    ("grpquota",            Opt_grpquota),
        fsparam_flag    ("quota",               Opt_quota),
        fsparam_flag    ("noquota",             Opt_noquota),
        fsparam_flag    ("usrquota",            Opt_usrquota),
        fsparam_flag    ("prjquota",            Opt_prjquota),
        fsparam_flag    ("barrier",             Opt_barrier),
        fsparam_u32     ("barrier",             Opt_barrier),
        fsparam_flag    ("nobarrier",           Opt_nobarrier),
        fsparam_flag    ("i_version",           Opt_removed),
        fsparam_flag    ("dax",                 Opt_dax),
        fsparam_enum    ("dax",                 Opt_dax_type, ext4_param_dax),
        fsparam_u32     ("stripe",              Opt_stripe),
        fsparam_flag    ("delalloc",            Opt_delalloc),
        fsparam_flag    ("nodelalloc",          Opt_nodelalloc),
        fsparam_flag    ("warn_on_error",       Opt_warn_on_error),
        fsparam_flag    ("nowarn_on_error",     Opt_nowarn_on_error),
        fsparam_u32     ("debug_want_extra_isize",
                                                Opt_debug_want_extra_isize),
        fsparam_flag    ("mblk_io_submit",      Opt_removed),
        fsparam_flag    ("nomblk_io_submit",    Opt_removed),
        fsparam_flag    ("block_validity",      Opt_block_validity),
        fsparam_flag    ("noblock_validity",    Opt_noblock_validity),
        fsparam_u32     ("inode_readahead_blks",
                                                Opt_inode_readahead_blks),
        fsparam_u32     ("journal_ioprio",      Opt_journal_ioprio),
        fsparam_u32     ("auto_da_alloc",       Opt_auto_da_alloc),
        fsparam_flag    ("auto_da_alloc",       Opt_auto_da_alloc),
        fsparam_flag    ("noauto_da_alloc",     Opt_noauto_da_alloc),
        fsparam_flag    ("dioread_nolock",      Opt_dioread_nolock),
        fsparam_flag    ("nodioread_nolock",    Opt_dioread_lock),
        fsparam_flag    ("dioread_lock",        Opt_dioread_lock),
        fsparam_flag    ("discard",             Opt_discard),
        fsparam_flag    ("nodiscard",           Opt_nodiscard),
        fsparam_u32     ("init_itable",         Opt_init_itable),
        fsparam_flag    ("init_itable",         Opt_init_itable),
        fsparam_flag    ("noinit_itable",       Opt_noinit_itable),
#ifdef CONFIG_EXT4_DEBUG
        fsparam_flag    ("fc_debug_force",      Opt_fc_debug_force),
        fsparam_u32     ("fc_debug_max_replay", Opt_fc_debug_max_replay),
#endif
        fsparam_u32     ("max_dir_size_kb",     Opt_max_dir_size_kb),
        fsparam_flag    ("test_dummy_encryption",
                                                Opt_test_dummy_encryption),
        fsparam_string  ("test_dummy_encryption",
                                                Opt_test_dummy_encryption),
        fsparam_flag    ("inlinecrypt",         Opt_inlinecrypt),
        fsparam_flag    ("nombcache",           Opt_nombcache),
        fsparam_flag    ("no_mbcache",          Opt_nombcache), /* for backward compatibility */
        fsparam_flag    ("prefetch_block_bitmaps",
                                                Opt_removed),
        fsparam_flag    ("no_prefetch_block_bitmaps",
                                                Opt_no_prefetch_block_bitmaps),
        fsparam_s32     ("mb_optimize_scan",    Opt_mb_optimize_scan),
        fsparam_string  ("check",               Opt_removed),   /* mount option from ext2/3 */
        fsparam_flag    ("nocheck",             Opt_removed),   /* mount option from ext2/3 */
        fsparam_flag    ("reservation",         Opt_removed),   /* mount option from ext2/3 */
        fsparam_flag    ("noreservation",       Opt_removed),   /* mount option from ext2/3 */
        fsparam_u32     ("journal",             Opt_removed),   /* mount option from ext2/3 */
        {}
};

#define DEFAULT_JOURNAL_IOPRIO (IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 3))

#define MOPT_SET        0x0001
#define MOPT_CLEAR      0x0002
#define MOPT_NOSUPPORT  0x0004
#define MOPT_EXPLICIT   0x0008
#ifdef CONFIG_QUOTA
#define MOPT_Q          0
#define MOPT_QFMT       0x0010
#else
#define MOPT_Q          MOPT_NOSUPPORT
#define MOPT_QFMT       MOPT_NOSUPPORT
#endif
#define MOPT_NO_EXT2    0x0020
#define MOPT_NO_EXT3    0x0040
#define MOPT_EXT4_ONLY  (MOPT_NO_EXT2 | MOPT_NO_EXT3)
#define MOPT_SKIP       0x0080
#define MOPT_2          0x0100

static const struct mount_opts {
        int     token;
        int     mount_opt;
        int     flags;
} ext4_mount_opts[] = {
        {Opt_minix_df, EXT4_MOUNT_MINIX_DF, MOPT_SET},
        {Opt_bsd_df, EXT4_MOUNT_MINIX_DF, MOPT_CLEAR},
        {Opt_grpid, EXT4_MOUNT_GRPID, MOPT_SET},
        {Opt_nogrpid, EXT4_MOUNT_GRPID, MOPT_CLEAR},
        {Opt_block_validity, EXT4_MOUNT_BLOCK_VALIDITY, MOPT_SET},
        {Opt_noblock_validity, EXT4_MOUNT_BLOCK_VALIDITY, MOPT_CLEAR},
        {Opt_dioread_nolock, EXT4_MOUNT_DIOREAD_NOLOCK,
         MOPT_EXT4_ONLY | MOPT_SET},
        {Opt_dioread_lock, EXT4_MOUNT_DIOREAD_NOLOCK,
         MOPT_EXT4_ONLY | MOPT_CLEAR},
        {Opt_discard, EXT4_MOUNT_DISCARD, MOPT_SET},
        {Opt_nodiscard, EXT4_MOUNT_DISCARD, MOPT_CLEAR},
        {Opt_delalloc, EXT4_MOUNT_DELALLOC,
         MOPT_EXT4_ONLY | MOPT_SET | MOPT_EXPLICIT},
        {Opt_nodelalloc, EXT4_MOUNT_DELALLOC,
         MOPT_EXT4_ONLY | MOPT_CLEAR},
        {Opt_warn_on_error, EXT4_MOUNT_WARN_ON_ERROR, MOPT_SET},
        {Opt_nowarn_on_error, EXT4_MOUNT_WARN_ON_ERROR, MOPT_CLEAR},
        {Opt_commit, 0, MOPT_NO_EXT2},
        {Opt_nojournal_checksum, EXT4_MOUNT_JOURNAL_CHECKSUM,
         MOPT_EXT4_ONLY | MOPT_CLEAR},
        {Opt_journal_checksum, EXT4_MOUNT_JOURNAL_CHECKSUM,
         MOPT_EXT4_ONLY | MOPT_SET | MOPT_EXPLICIT},
        {Opt_journal_async_commit, (EXT4_MOUNT_JOURNAL_ASYNC_COMMIT |
                                    EXT4_MOUNT_JOURNAL_CHECKSUM),
         MOPT_EXT4_ONLY | MOPT_SET | MOPT_EXPLICIT},
        {Opt_noload, EXT4_MOUNT_NOLOAD, MOPT_NO_EXT2 | MOPT_SET},
        {Opt_data_err, EXT4_MOUNT_DATA_ERR_ABORT, MOPT_NO_EXT2},
        {Opt_barrier, EXT4_MOUNT_BARRIER, MOPT_SET},
        {Opt_nobarrier, EXT4_MOUNT_BARRIER, MOPT_CLEAR},
        {Opt_noauto_da_alloc, EXT4_MOUNT_NO_AUTO_DA_ALLOC, MOPT_SET},
        {Opt_auto_da_alloc, EXT4_MOUNT_NO_AUTO_DA_ALLOC, MOPT_CLEAR},
        {Opt_noinit_itable, EXT4_MOUNT_INIT_INODE_TABLE, MOPT_CLEAR},
        {Opt_dax_type, 0, MOPT_EXT4_ONLY},
        {Opt_journal_dev, 0, MOPT_NO_EXT2},
        {Opt_journal_path, 0, MOPT_NO_EXT2},
        {Opt_journal_ioprio, 0, MOPT_NO_EXT2},
        {Opt_data, 0, MOPT_NO_EXT2},
        {Opt_user_xattr, EXT4_MOUNT_XATTR_USER, MOPT_SET},
#ifdef CONFIG_EXT4_FS_POSIX_ACL
        {Opt_acl, EXT4_MOUNT_POSIX_ACL, MOPT_SET},
#else
        {Opt_acl, 0, MOPT_NOSUPPORT},
#endif
        {Opt_nouid32, EXT4_MOUNT_NO_UID32, MOPT_SET},
        {Opt_debug, EXT4_MOUNT_DEBUG, MOPT_SET},
        {Opt_quota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA, MOPT_SET | MOPT_Q},
        {Opt_usrquota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA,
                                                        MOPT_SET | MOPT_Q},
        {Opt_grpquota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_GRPQUOTA,
                                                        MOPT_SET | MOPT_Q},
        {Opt_prjquota, EXT4_MOUNT_QUOTA | EXT4_MOUNT_PRJQUOTA,
                                                        MOPT_SET | MOPT_Q},
        {Opt_noquota, (EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA |
                       EXT4_MOUNT_GRPQUOTA | EXT4_MOUNT_PRJQUOTA),
                                                        MOPT_CLEAR | MOPT_Q},
        {Opt_usrjquota, 0, MOPT_Q},
        {Opt_grpjquota, 0, MOPT_Q},
        {Opt_jqfmt, 0, MOPT_QFMT},
        {Opt_nombcache, EXT4_MOUNT_NO_MBCACHE, MOPT_SET},
        {Opt_no_prefetch_block_bitmaps, EXT4_MOUNT_NO_PREFETCH_BLOCK_BITMAPS,
         MOPT_SET},
#ifdef CONFIG_EXT4_DEBUG
        {Opt_fc_debug_force, EXT4_MOUNT2_JOURNAL_FAST_COMMIT,
         MOPT_SET | MOPT_2 | MOPT_EXT4_ONLY},
#endif
        {Opt_err, 0, 0}
};

#if IS_ENABLED(CONFIG_UNICODE)
static const struct ext4_sb_encodings {
        __u16 magic;
        char *name;
        unsigned int version;
} ext4_sb_encoding_map[] = {
        {EXT4_ENC_UTF8_12_1, "utf8", UNICODE_AGE(12, 1, 0)},
};

static const struct ext4_sb_encodings *
ext4_sb_read_encoding(const struct ext4_super_block *es)
{
        __u16 magic = le16_to_cpu(es->s_encoding);
        int i;

        for (i = 0; i < ARRAY_SIZE(ext4_sb_encoding_map); i++)
                if (magic == ext4_sb_encoding_map[i].magic)
                        return &ext4_sb_encoding_map[i];

        return NULL;
}
#endif

#define EXT4_SPEC_JQUOTA                        (1 <<  0)
#define EXT4_SPEC_JQFMT                         (1 <<  1)
#define EXT4_SPEC_DATAJ                         (1 <<  2)
#define EXT4_SPEC_SB_BLOCK                      (1 <<  3)
#define EXT4_SPEC_JOURNAL_DEV                   (1 <<  4)
#define EXT4_SPEC_JOURNAL_IOPRIO                (1 <<  5)
#define EXT4_SPEC_s_want_extra_isize            (1 <<  7)
#define EXT4_SPEC_s_max_batch_time              (1 <<  8)
#define EXT4_SPEC_s_min_batch_time              (1 <<  9)
#define EXT4_SPEC_s_inode_readahead_blks        (1 << 10)
#define EXT4_SPEC_s_li_wait_mult                (1 << 11)
#define EXT4_SPEC_s_max_dir_size_kb             (1 << 12)
#define EXT4_SPEC_s_stripe                      (1 << 13)
#define EXT4_SPEC_s_resuid                      (1 << 14)
#define EXT4_SPEC_s_resgid                      (1 << 15)
#define EXT4_SPEC_s_commit_interval             (1 << 16)
#define EXT4_SPEC_s_fc_debug_max_replay         (1 << 17)
#define EXT4_SPEC_s_sb_block                    (1 << 18)
#define EXT4_SPEC_mb_optimize_scan              (1 << 19)

struct ext4_fs_context {
        char            *s_qf_names[EXT4_MAXQUOTAS];
        struct fscrypt_dummy_policy dummy_enc_policy;
        int             s_jquota_fmt;   /* Format of quota to use */
#ifdef CONFIG_EXT4_DEBUG
        int s_fc_debug_max_replay;
#endif
        unsigned short  qname_spec;
        unsigned long   vals_s_flags;   /* Bits to set in s_flags */
        unsigned long   mask_s_flags;   /* Bits changed in s_flags */
        unsigned long   journal_devnum;
        unsigned long   s_commit_interval;
        unsigned long   s_stripe;
        unsigned int    s_inode_readahead_blks;
        unsigned int    s_want_extra_isize;
        unsigned int    s_li_wait_mult;
        unsigned int    s_max_dir_size_kb;
        unsigned int    journal_ioprio;
        unsigned int    vals_s_mount_opt;
        unsigned int    mask_s_mount_opt;
        unsigned int    vals_s_mount_opt2;
        unsigned int    mask_s_mount_opt2;
        unsigned long   vals_s_mount_flags;
        unsigned long   mask_s_mount_flags;
        unsigned int    opt_flags;      /* MOPT flags */
        unsigned int    spec;
        u32             s_max_batch_time;
        u32             s_min_batch_time;
        kuid_t          s_resuid;
        kgid_t          s_resgid;
        ext4_fsblk_t    s_sb_block;
};

static void ext4_fc_free(struct fs_context *fc)
{
        struct ext4_fs_context *ctx = fc->fs_private;
        int i;

        if (!ctx)
                return;

        for (i = 0; i < EXT4_MAXQUOTAS; i++)
                kfree(ctx->s_qf_names[i]);

        fscrypt_free_dummy_policy(&ctx->dummy_enc_policy);
        kfree(ctx);
}

int ext4_init_fs_context(struct fs_context *fc)
{
        struct ext4_fs_context *ctx;

        ctx = kzalloc(sizeof(struct ext4_fs_context), GFP_KERNEL);
        if (!ctx)
                return -ENOMEM;

        fc->fs_private = ctx;
        fc->ops = &ext4_context_ops;

        return 0;
}

#ifdef CONFIG_QUOTA
/*
 * Note the name of the specified quota file.
 */
static int note_qf_name(struct fs_context *fc, int qtype,
                       struct fs_parameter *param)
{
        struct ext4_fs_context *ctx = fc->fs_private;
        char *qname;

        if (param->size < 1) {
                ext4_msg(NULL, KERN_ERR, "Missing quota name");
                return -EINVAL;
        }
        if (strchr(param->string, '/')) {
                ext4_msg(NULL, KERN_ERR,
                         "quotafile must be on filesystem root");
                return -EINVAL;
        }
        if (ctx->s_qf_names[qtype]) {
                if (strcmp(ctx->s_qf_names[qtype], param->string) != 0) {
                        ext4_msg(NULL, KERN_ERR,
                                 "%s quota file already specified",
                                 QTYPE2NAME(qtype));
                        return -EINVAL;
                }
                return 0;
        }

        qname = kmemdup_nul(param->string, param->size, GFP_KERNEL);
        if (!qname) {
                ext4_msg(NULL, KERN_ERR,
                         "Not enough memory for storing quotafile name");
                return -ENOMEM;
        }
        ctx->s_qf_names[qtype] = qname;
        ctx->qname_spec |= 1 << qtype;
        ctx->spec |= EXT4_SPEC_JQUOTA;
        return 0;
}

/*
 * Clear the name of the specified quota file.
 */
static int unnote_qf_name(struct fs_context *fc, int qtype)
{
        struct ext4_fs_context *ctx = fc->fs_private;

        if (ctx->s_qf_names[qtype])
                kfree(ctx->s_qf_names[qtype]);

        ctx->s_qf_names[qtype] = NULL;
        ctx->qname_spec |= 1 << qtype;
        ctx->spec |= EXT4_SPEC_JQUOTA;
        return 0;
}
#endif

static int ext4_parse_test_dummy_encryption(const struct fs_parameter *param,
                                            struct ext4_fs_context *ctx)
{
        int err;

        if (!IS_ENABLED(CONFIG_FS_ENCRYPTION)) {
                ext4_msg(NULL, KERN_WARNING,
                         "test_dummy_encryption option not supported");
                return -EINVAL;
        }
        err = fscrypt_parse_test_dummy_encryption(param,
                                                  &ctx->dummy_enc_policy);
        if (err == -EINVAL) {
                ext4_msg(NULL, KERN_WARNING,
                         "Value of option \"%s\" is unrecognized", param->key);
        } else if (err == -EEXIST) {
                ext4_msg(NULL, KERN_WARNING,
                         "Conflicting test_dummy_encryption options");
                return -EINVAL;
        }
        return err;
}

#define EXT4_SET_CTX(name)                                              \
static inline void ctx_set_##name(struct ext4_fs_context *ctx,          \
                                  unsigned long flag)                   \
{                                                                       \
        ctx->mask_s_##name |= flag;                                     \
        ctx->vals_s_##name |= flag;                                     \
}

#define EXT4_CLEAR_CTX(name)                                            \
static inline void ctx_clear_##name(struct ext4_fs_context *ctx,        \
                                    unsigned long flag)                 \
{                                                                       \
        ctx->mask_s_##name |= flag;                                     \
        ctx->vals_s_##name &= ~flag;                                    \
}

#define EXT4_TEST_CTX(name)                                             \
static inline unsigned long                                             \
ctx_test_##name(struct ext4_fs_context *ctx, unsigned long flag)        \
{                                                                       \
        return (ctx->vals_s_##name & flag);                             \
}

EXT4_SET_CTX(flags); /* set only */
EXT4_SET_CTX(mount_opt);
EXT4_CLEAR_CTX(mount_opt);
EXT4_TEST_CTX(mount_opt);
EXT4_SET_CTX(mount_opt2);
EXT4_CLEAR_CTX(mount_opt2);
EXT4_TEST_CTX(mount_opt2);

static inline void ctx_set_mount_flag(struct ext4_fs_context *ctx, int bit)
{
        set_bit(bit, &ctx->mask_s_mount_flags);
        set_bit(bit, &ctx->vals_s_mount_flags);
}

static int ext4_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
        struct ext4_fs_context *ctx = fc->fs_private;
        struct fs_parse_result result;
        const struct mount_opts *m;
        int is_remount;
        kuid_t uid;
        kgid_t gid;
        int token;

        token = fs_parse(fc, ext4_param_specs, param, &result);
        if (token < 0)
                return token;
        is_remount = fc->purpose == FS_CONTEXT_FOR_RECONFIGURE;

        for (m = ext4_mount_opts; m->token != Opt_err; m++)
                if (token == m->token)
                        break;

        ctx->opt_flags |= m->flags;

        if (m->flags & MOPT_EXPLICIT) {
                if (m->mount_opt & EXT4_MOUNT_DELALLOC) {
                        ctx_set_mount_opt2(ctx, EXT4_MOUNT2_EXPLICIT_DELALLOC);
                } else if (m->mount_opt & EXT4_MOUNT_JOURNAL_CHECKSUM) {
                        ctx_set_mount_opt2(ctx,
                                       EXT4_MOUNT2_EXPLICIT_JOURNAL_CHECKSUM);
                } else
                        return -EINVAL;
        }

        if (m->flags & MOPT_NOSUPPORT) {
                ext4_msg(NULL, KERN_ERR, "%s option not supported",
                         param->key);
                return 0;
        }

        switch (token) {
#ifdef CONFIG_QUOTA
        case Opt_usrjquota:
                if (!*param->string)
                        return unnote_qf_name(fc, USRQUOTA);
                else
                        return note_qf_name(fc, USRQUOTA, param);
        case Opt_grpjquota:
                if (!*param->string)
                        return unnote_qf_name(fc, GRPQUOTA);
                else
                        return note_qf_name(fc, GRPQUOTA, param);
#endif
        case Opt_sb:
                if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
                        ext4_msg(NULL, KERN_WARNING,
                                 "Ignoring %s option on remount", param->key);
                } else {
                        ctx->s_sb_block = result.uint_32;
                        ctx->spec |= EXT4_SPEC_s_sb_block;
                }
                return 0;
        case Opt_removed:
                ext4_msg(NULL, KERN_WARNING, "Ignoring removed %s option",
                         param->key);
                return 0;
        case Opt_abort:
                ctx_set_mount_flag(ctx, EXT4_MF_FS_ABORTED);
                return 0;
        case Opt_inlinecrypt:
#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
                ctx_set_flags(ctx, SB_INLINECRYPT);
#else
                ext4_msg(NULL, KERN_ERR, "inline encryption not supported");
#endif
                return 0;
        case Opt_errors:
                ctx_clear_mount_opt(ctx, EXT4_MOUNT_ERRORS_MASK);
                ctx_set_mount_opt(ctx, result.uint_32);
                return 0;
#ifdef CONFIG_QUOTA
        case Opt_jqfmt:
                ctx->s_jquota_fmt = result.uint_32;
                ctx->spec |= EXT4_SPEC_JQFMT;
                return 0;
#endif
        case Opt_data:
                ctx_clear_mount_opt(ctx, EXT4_MOUNT_DATA_FLAGS);
                ctx_set_mount_opt(ctx, result.uint_32);
                ctx->spec |= EXT4_SPEC_DATAJ;
                return 0;
        case Opt_commit:
                if (result.uint_32 == 0)
                        result.uint_32 = JBD2_DEFAULT_MAX_COMMIT_AGE;
                else if (result.uint_32 > INT_MAX / HZ) {
                        ext4_msg(NULL, KERN_ERR,
                                 "Invalid commit interval %d, "
                                 "must be smaller than %d",
                                 result.uint_32, INT_MAX / HZ);
                        return -EINVAL;
                }
                ctx->s_commit_interval = HZ * result.uint_32;
                ctx->spec |= EXT4_SPEC_s_commit_interval;
                return 0;
        case Opt_debug_want_extra_isize:
                if ((result.uint_32 & 1) || (result.uint_32 < 4)) {
                        ext4_msg(NULL, KERN_ERR,
                                 "Invalid want_extra_isize %d", result.uint_32);
                        return -EINVAL;
                }
                ctx->s_want_extra_isize = result.uint_32;
                ctx->spec |= EXT4_SPEC_s_want_extra_isize;
                return 0;
        case Opt_max_batch_time:
                ctx->s_max_batch_time = result.uint_32;
                ctx->spec |= EXT4_SPEC_s_max_batch_time;
                return 0;
        case Opt_min_batch_time:
                ctx->s_min_batch_time = result.uint_32;
                ctx->spec |= EXT4_SPEC_s_min_batch_time;
                return 0;
        case Opt_inode_readahead_blks:
                if (result.uint_32 &&
                    (result.uint_32 > (1 << 30) ||
                     !is_power_of_2(result.uint_32))) {
                        ext4_msg(NULL, KERN_ERR,
                                 "EXT4-fs: inode_readahead_blks must be "
                                 "0 or a power of 2 smaller than 2^31");
                        return -EINVAL;
                }
                ctx->s_inode_readahead_blks = result.uint_32;
                ctx->spec |= EXT4_SPEC_s_inode_readahead_blks;
                return 0;
        case Opt_init_itable:
                ctx_set_mount_opt(ctx, EXT4_MOUNT_INIT_INODE_TABLE);
                ctx->s_li_wait_mult = EXT4_DEF_LI_WAIT_MULT;
                if (param->type == fs_value_is_string)
                        ctx->s_li_wait_mult = result.uint_32;
                ctx->spec |= EXT4_SPEC_s_li_wait_mult;
                return 0;
        case Opt_max_dir_size_kb:
                ctx->s_max_dir_size_kb = result.uint_32;
                ctx->spec |= EXT4_SPEC_s_max_dir_size_kb;
                return 0;
#ifdef CONFIG_EXT4_DEBUG
        case Opt_fc_debug_max_replay:
                ctx->s_fc_debug_max_replay = result.uint_32;
                ctx->spec |= EXT4_SPEC_s_fc_debug_max_replay;
                return 0;
#endif
        case Opt_stripe:
                ctx->s_stripe = result.uint_32;
                ctx->spec |= EXT4_SPEC_s_stripe;
                return 0;
        case Opt_resuid:
                uid = make_kuid(current_user_ns(), result.uint_32);
                if (!uid_valid(uid)) {
                        ext4_msg(NULL, KERN_ERR, "Invalid uid value %d",
                                 result.uint_32);
                        return -EINVAL;
                }
                ctx->s_resuid = uid;
                ctx->spec |= EXT4_SPEC_s_resuid;
                return 0;
        case Opt_resgid:
                gid = make_kgid(current_user_ns(), result.uint_32);
                if (!gid_valid(gid)) {
                        ext4_msg(NULL, KERN_ERR, "Invalid gid value %d",
                                 result.uint_32);
                        return -EINVAL;
                }
                ctx->s_resgid = gid;
                ctx->spec |= EXT4_SPEC_s_resgid;
                return 0;
        case Opt_journal_dev:
                if (is_remount) {
                        ext4_msg(NULL, KERN_ERR,
                                 "Cannot specify journal on remount");
                        return -EINVAL;
                }
                ctx->journal_devnum = result.uint_32;
                ctx->spec |= EXT4_SPEC_JOURNAL_DEV;
                return 0;
        case Opt_journal_path:
        {
                struct inode *journal_inode;
                struct path path;
                int error;

                if (is_remount) {
                        ext4_msg(NULL, KERN_ERR,
                                 "Cannot specify journal on remount");
                        return -EINVAL;
                }

                error = fs_lookup_param(fc, param, 1, LOOKUP_FOLLOW, &path);
                if (error) {
                        ext4_msg(NULL, KERN_ERR, "error: could not find "
                                 "journal device path");
                        return -EINVAL;
                }

                journal_inode = d_inode(path.dentry);
                ctx->journal_devnum = new_encode_dev(journal_inode->i_rdev);
                ctx->spec |= EXT4_SPEC_JOURNAL_DEV;
                path_put(&path);
                return 0;
        }
        case Opt_journal_ioprio:
                if (result.uint_32 > 7) {
                        ext4_msg(NULL, KERN_ERR, "Invalid journal IO priority"
                                 " (must be 0-7)");
                        return -EINVAL;
                }
                ctx->journal_ioprio =
                        IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, result.uint_32);
                ctx->spec |= EXT4_SPEC_JOURNAL_IOPRIO;
                return 0;
        case Opt_test_dummy_encryption:
                return ext4_parse_test_dummy_encryption(param, ctx);
        case Opt_dax:
        case Opt_dax_type:
#ifdef CONFIG_FS_DAX
        {
                int type = (token == Opt_dax) ?
                           Opt_dax : result.uint_32;

                switch (type) {
                case Opt_dax:
                case Opt_dax_always:
                        ctx_set_mount_opt(ctx, EXT4_MOUNT_DAX_ALWAYS);
                        ctx_clear_mount_opt2(ctx, EXT4_MOUNT2_DAX_NEVER);
                        break;
                case Opt_dax_never:
                        ctx_set_mount_opt2(ctx, EXT4_MOUNT2_DAX_NEVER);
                        ctx_clear_mount_opt(ctx, EXT4_MOUNT_DAX_ALWAYS);
                        break;
                case Opt_dax_inode:
                        ctx_clear_mount_opt(ctx, EXT4_MOUNT_DAX_ALWAYS);
                        ctx_clear_mount_opt2(ctx, EXT4_MOUNT2_DAX_NEVER);
                        /* Strictly for printing options */
                        ctx_set_mount_opt2(ctx, EXT4_MOUNT2_DAX_INODE);
                        break;
                }
                return 0;
        }
#else
                ext4_msg(NULL, KERN_INFO, "dax option not supported");
                return -EINVAL;
#endif
        case Opt_data_err:
                if (result.uint_32 == Opt_data_err_abort)
                        ctx_set_mount_opt(ctx, m->mount_opt);
                else if (result.uint_32 == Opt_data_err_ignore)
                        ctx_clear_mount_opt(ctx, m->mount_opt);
                return 0;
        case Opt_mb_optimize_scan:
                if (result.int_32 == 1) {
                        ctx_set_mount_opt2(ctx, EXT4_MOUNT2_MB_OPTIMIZE_SCAN);
                        ctx->spec |= EXT4_SPEC_mb_optimize_scan;
                } else if (result.int_32 == 0) {
                        ctx_clear_mount_opt2(ctx, EXT4_MOUNT2_MB_OPTIMIZE_SCAN);
                        ctx->spec |= EXT4_SPEC_mb_optimize_scan;
                } else {
                        ext4_msg(NULL, KERN_WARNING,
                                 "mb_optimize_scan should be set to 0 or 1.");
                        return -EINVAL;
                }
                return 0;
        }

        /*
         * At this point we should only be getting options requiring MOPT_SET,
         * or MOPT_CLEAR. Anything else is a bug
         */
        if (m->token == Opt_err) {
                ext4_msg(NULL, KERN_WARNING, "buggy handling of option %s",
                         param->key);
                WARN_ON(1);
                return -EINVAL;
        }

        else {
                unsigned int set = 0;

                if ((param->type == fs_value_is_flag) ||
                    result.uint_32 > 0)
                        set = 1;

                if (m->flags & MOPT_CLEAR)
                        set = !set;
                else if (unlikely(!(m->flags & MOPT_SET))) {
                        ext4_msg(NULL, KERN_WARNING,
                                 "buggy handling of option %s",
                                 param->key);
                        WARN_ON(1);
                        return -EINVAL;
                }
                if (m->flags & MOPT_2) {
                        if (set != 0)
                                ctx_set_mount_opt2(ctx, m->mount_opt);
                        else
                                ctx_clear_mount_opt2(ctx, m->mount_opt);
                } else {
                        if (set != 0)
                                ctx_set_mount_opt(ctx, m->mount_opt);
                        else
                                ctx_clear_mount_opt(ctx, m->mount_opt);
                }
        }

        return 0;
}

static int parse_options(struct fs_context *fc, char *options)
{
        struct fs_parameter param;
        int ret;
        char *key;

        if (!options)
                return 0;

        while ((key = strsep(&options, ",")) != NULL) {
                if (*key) {
                        size_t v_len = 0;
                        char *value = strchr(key, '=');

                        param.type = fs_value_is_flag;
                        param.string = NULL;

                        if (value) {
                                if (value == key)
                                        continue;

                                *value++ = 0;
                                v_len = strlen(value);
                                param.string = kmemdup_nul(value, v_len,
                                                           GFP_KERNEL);
                                if (!param.string)
                                        return -ENOMEM;
                                param.type = fs_value_is_string;
                        }

                        param.key = key;
                        param.size = v_len;

                        ret = ext4_parse_param(fc, &param);
                        if (param.string)
                                kfree(param.string);
                        if (ret < 0)
                                return ret;
                }
        }

        ret = ext4_validate_options(fc);
        if (ret < 0)
                return ret;

        return 0;
}

static int parse_apply_sb_mount_options(struct super_block *sb,
                                        struct ext4_fs_context *m_ctx)
{
        struct ext4_sb_info *sbi = EXT4_SB(sb);
        char *s_mount_opts = NULL;
        struct ext4_fs_context *s_ctx = NULL;
        struct fs_context *fc = NULL;
        int ret = -ENOMEM;

        if (!sbi->s_es->s_mount_opts[0])
                return 0;

        s_mount_opts = kstrndup(sbi->s_es->s_mount_opts,
                                sizeof(sbi->s_es->s_mount_opts),
                                GFP_KERNEL);
        if (!s_mount_opts)
                return ret;

        fc = kzalloc(sizeof(struct fs_context), GFP_KERNEL);
        if (!fc)
                goto out_free;

        s_ctx = kzalloc(sizeof(struct ext4_fs_context), GFP_KERNEL);
        if (!s_ctx)
                goto out_free;

        fc->fs_private = s_ctx;
        fc->s_fs_info = sbi;

        ret = parse_options(fc, s_mount_opts);
        if (ret < 0)
                goto parse_failed;

        ret = ext4_check_opt_consistency(fc, sb);
        if (ret < 0) {
parse_failed:
                ext4_msg(sb, KERN_WARNING,
                         "failed to parse options in superblock: %s",
                         s_mount_opts);
                ret = 0;
                goto out_free;
        }

        if (s_ctx->spec & EXT4_SPEC_JOURNAL_DEV)
                m_ctx->journal_devnum = s_ctx->journal_devnum;
        if (s_ctx->spec & EXT4_SPEC_JOURNAL_IOPRIO)
                m_ctx->journal_ioprio = s_ctx->journal_ioprio;

        ext4_apply_options(fc, sb);
        ret = 0;

out_free:
        if (fc) {
                ext4_fc_free(fc);
                kfree(fc);
        }
        kfree(s_mount_opts);
        return ret;
}

static void ext4_apply_quota_options(struct fs_context *fc,
                                     struct super_block *sb)
{
#ifdef CONFIG_QUOTA
        bool quota_feature = ext4_has_feature_quota(sb);
        struct ext4_fs_context *ctx = fc->fs_private;
        struct ext4_sb_info *sbi = EXT4_SB(sb);
        char *qname;
        int i;

        if (quota_feature)
                return;

        if (ctx->spec & EXT4_SPEC_JQUOTA) {
                for (i = 0; i < EXT4_MAXQUOTAS; i++) {
                        if (!(ctx->qname_spec & (1 << i)))
                                continue;

                        qname = ctx->s_qf_names[i]; /* May be NULL */
                        if (qname)
                                set_opt(sb, QUOTA);
                        ctx->s_qf_names[i] = NULL;
                        qname = rcu_replace_pointer(sbi->s_qf_names[i], qname,
                                                lockdep_is_held(&sb->s_umount));
                        if (qname)
                                kfree_rcu_mightsleep(qname);
                }
        }

        if (ctx->spec & EXT4_SPEC_JQFMT)
                sbi->s_jquota_fmt = ctx->s_jquota_fmt;
#endif
}

/*
 * Check quota settings consistency.
 */
static int ext4_check_quota_consistency(struct fs_context *fc,
                                        struct super_block *sb)
{
#ifdef CONFIG_QUOTA
        struct ext4_fs_context *ctx = fc->fs_private;
        struct ext4_sb_info *sbi = EXT4_SB(sb);
        bool quota_feature = ext4_has_feature_quota(sb);
        bool quota_loaded = sb_any_quota_loaded(sb);
        bool usr_qf_name, grp_qf_name, usrquota, grpquota;
        int quota_flags, i;

        /*
         * We do the test below only for project quotas. 'usrquota' and
         * 'grpquota' mount options are allowed even without quota feature
         * to support legacy quotas in quota files.
         */
        if (ctx_test_mount_opt(ctx, EXT4_MOUNT_PRJQUOTA) &&
            !ext4_has_feature_project(sb)) {
                ext4_msg(NULL, KERN_ERR, "Project quota feature not enabled. "
                         "Cannot enable project quota enforcement.");
                return -EINVAL;
        }

        quota_flags = EXT4_MOUNT_QUOTA | EXT4_MOUNT_USRQUOTA |
                      EXT4_MOUNT_GRPQUOTA | EXT4_MOUNT_PRJQUOTA;
        if (quota_loaded &&
            ctx->mask_s_mount_opt & quota_flags &&
            !ctx_test_mount_opt(ctx, quota_flags))
                goto err_quota_change;

        if (ctx->spec & EXT4_SPEC_JQUOTA) {

                for (i = 0; i < EXT4_MAXQUOTAS; i++) {
                        if (!(ctx->qname_spec & (1 << i)))
                                continue;

                        if (quota_loaded &&
                            !!sbi->s_qf_names[i] != !!ctx->s_qf_names[i])
                                goto err_jquota_change;

                        if (sbi->s_qf_names[i] && ctx->s_qf_names[i] &&
                            strcmp(get_qf_name(sb, sbi, i),
                                   ctx->s_qf_names[i]) != 0)
                                goto err_jquota_specified;
                }

                if (quota_feature) {
                        ext4_msg(NULL, KERN_INFO,
                                 "Journaled quota options ignored when "
                                 "QUOTA feature is enabled");
                        return 0;
                }
        }

        if (ctx->spec & EXT4_SPEC_JQFMT) {
                if (sbi->s_jquota_fmt != ctx->s_jquota_fmt && quota_loaded)
                        goto err_jquota_change;
                if (quota_feature) {
                        ext4_msg(NULL, KERN_INFO, "Quota format mount options "
                                 "ignored when QUOTA feature is enabled");
                        return 0;
                }
        }

        /* Make sure we don't mix old and new quota format */
        usr_qf_name = (get_qf_name(sb, sbi, USRQUOTA) ||
                       ctx->s_qf_names[USRQUOTA]);
        grp_qf_name = (get_qf_name(sb, sbi, GRPQUOTA) ||
                       ctx->s_qf_names[GRPQUOTA]);

        usrquota = (ctx_test_mount_opt(ctx, EXT4_MOUNT_USRQUOTA) ||
                    test_opt(sb, USRQUOTA));

        grpquota = (ctx_test_mount_opt(ctx, EXT4_MOUNT_GRPQUOTA) ||
                    test_opt(sb, GRPQUOTA));

        if (usr_qf_name) {
                ctx_clear_mount_opt(ctx, EXT4_MOUNT_USRQUOTA);
                usrquota = false;
        }
        if (grp_qf_name) {
                ctx_clear_mount_opt(ctx, EXT4_MOUNT_GRPQUOTA);
                grpquota = false;
        }

        if (usr_qf_name || grp_qf_name) {
                if (usrquota || grpquota) {
                        ext4_msg(NULL, KERN_ERR, "old and new quota "
                                 "format mixing");
                        return -EINVAL;
                }

                if (!(ctx->spec & EXT4_SPEC_JQFMT || sbi->s_jquota_fmt)) {
                        ext4_msg(NULL, KERN_ERR, "journaled quota format "
                                 "not specified");
                        return -EINVAL;
                }
        }

        return 0;

err_quota_change:
        ext4_msg(NULL, KERN_ERR,
                 "Cannot change quota options when quota turned on");
        return -EINVAL;
err_jquota_change:
        ext4_msg(NULL, KERN_ERR, "Cannot change journaled quota "
                 "options when quota turned on");
        return -EINVAL;
err_jquota_specified:
        ext4_msg(NULL, KERN_ERR, "%s quota file already specified",
                 QTYPE2NAME(i));
        return -EINVAL;
#else
        return 0;
#endif
}

static int ext4_check_test_dummy_encryption(const struct fs_context *fc,
                                            struct super_block *sb)
{
        const struct ext4_fs_context *ctx = fc->fs_private;
        const struct ext4_sb_info *sbi = EXT4_SB(sb);

        if (!fscrypt_is_dummy_policy_set(&ctx->dummy_enc_policy))
                return 0;

        if (!ext4_has_feature_encrypt(sb)) {
                ext4_msg(NULL, KERN_WARNING,
                         "test_dummy_encryption requires encrypt feature");
                return -EINVAL;
        }
        /*
         * This mount option is just for testing, and it's not worthwhile to
         * implement the extra complexity (e.g. RCU protection) that would be
         * needed to allow it to be set or changed during remount.  We do allow
         * it to be specified during remount, but only if there is no change.
         */
        if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
                if (fscrypt_dummy_policies_equal(&sbi->s_dummy_enc_policy,
                                                 &ctx->dummy_enc_policy))
                        return 0;
                ext4_msg(NULL, KERN_WARNING,
                         "Can't set or change test_dummy_encryption on remount");
                return -EINVAL;
        }
        /* Also make sure s_mount_opts didn't contain a conflicting value. */
        if (fscrypt_is_dummy_policy_set(&sbi->s_dummy_enc_policy)) {
                if (fscrypt_dummy_policies_equal(&sbi->s_dummy_enc_policy,
                                                 &ctx->dummy_enc_policy))
                        return 0;
                ext4_msg(NULL, KERN_WARNING,
                         "Conflicting test_dummy_encryption options");
                return -EINVAL;
        }
        return 0;
}

static void ext4_apply_test_dummy_encryption(struct ext4_fs_context *ctx,
                                             struct super_block *sb)
{
        if (!fscrypt_is_dummy_policy_set(&ctx->dummy_enc_policy) ||
            /* if already set, it was already verified to be the same */
            fscrypt_is_dummy_policy_set(&EXT4_SB(sb)->s_dummy_enc_policy))
                return;
        EXT4_SB(sb)->s_dummy_enc_policy = ctx->dummy_enc_policy;
        memset(&ctx->dummy_enc_policy, 0, sizeof(ctx->dummy_enc_policy));
        ext4_msg(sb, KERN_WARNING, "Test dummy encryption mode enabled");
}

static int ext4_check_opt_consistency(struct fs_context *fc,
                                      struct super_block *sb)
{
        struct ext4_fs_context *ctx = fc->fs_private;
        struct ext4_sb_info *sbi = fc->s_fs_info;
        int is_remount = fc->purpose == FS_CONTEXT_FOR_RECONFIGURE;
        int err;

        if ((ctx->opt_flags & MOPT_NO_EXT2) && IS_EXT2_SB(sb)) {
                ext4_msg(NULL, KERN_ERR,
                         "Mount option(s) incompatible with ext2");
                return -EINVAL;
        }
        if ((ctx->opt_flags & MOPT_NO_EXT3) && IS_EXT3_SB(sb)) {
                ext4_msg(NULL, KERN_ERR,
                         "Mount option(s) incompatible with ext3");
                return -EINVAL;
        }

        if (ctx->s_want_extra_isize >
            (sbi->s_inode_size - EXT4_GOOD_OLD_INODE_SIZE)) {
                ext4_msg(NULL, KERN_ERR,
                         "Invalid want_extra_isize %d",
                         ctx->s_want_extra_isize);
                return -EINVAL;
        }

        if (ctx_test_mount_opt(ctx, EXT4_MOUNT_DIOREAD_NOLOCK)) {
                int blocksize =
                        BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
                if (blocksize < PAGE_SIZE)
                        ext4_msg(NULL, KERN_WARNING, "Warning: mounting with an "
                                 "experimental mount option 'dioread_nolock' "
                                 "for blocksize < PAGE_SIZE");
        }

        err = ext4_check_test_dummy_encryption(fc, sb);
        if (err)
                return err;

        if ((ctx->spec & EXT4_SPEC_DATAJ) && is_remount) {
                if (!sbi->s_journal) {
                        ext4_msg(NULL, KERN_WARNING,
                                 "Remounting file system with no journal "
                                 "so ignoring journalled data option");
                        ctx_clear_mount_opt(ctx, EXT4_MOUNT_DATA_FLAGS);
                } else if (ctx_test_mount_opt(ctx, EXT4_MOUNT_DATA_FLAGS) !=
                           test_opt(sb, DATA_FLAGS)) {
                        ext4_msg(NULL, KERN_ERR, "Cannot change data mode "
                                 "on remount");
                        return -EINVAL;
                }
        }

        if (is_remount) {
                if (ctx_test_mount_opt(ctx, EXT4_MOUNT_DAX_ALWAYS) &&
                    (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)) {
                        ext4_msg(NULL, KERN_ERR, "can't mount with "
                                 "both data=journal and dax");
                        return -EINVAL;
                }

                if (ctx_test_mount_opt(ctx, EXT4_MOUNT_DAX_ALWAYS) &&
                    (!(sbi->s_mount_opt & EXT4_MOUNT_DAX_ALWAYS) ||
                     (sbi->s_mount_opt2 & EXT4_MOUNT2_DAX_NEVER))) {
fail_dax_change_remount:
                        ext4_msg(NULL, KERN_ERR, "can't change "
                                 "dax mount option while remounting");
                        return -EINVAL;
                } else if (ctx_test_mount_opt2(ctx, EXT4_MOUNT2_DAX_NEVER) &&
                         (!(sbi->s_mount_opt2 & EXT4_MOUNT2_DAX_NEVER) ||
                          (sbi->s_mount_opt & EXT4_MOUNT_DAX_ALWAYS))) {
                        goto fail_dax_change_remount;
                } else if (ctx_test_mount_opt2(ctx, EXT4_MOUNT2_DAX_INODE) &&
                           ((sbi->s_mount_opt & EXT4_MOUNT_DAX_ALWAYS) ||
                            (sbi->s_mount_opt2 & EXT4_MOUNT2_DAX_NEVER) ||
                            !(sbi->s_mount_opt2 & EXT4_MOUNT2_DAX_INODE))) {
                        goto fail_dax_change_remount;
                }
        }

        return ext4_check_quota_consistency(fc, sb);
}

static void ext4_apply_options(struct fs_context *fc, struct super_block *sb)
{
        struct ext4_fs_context *ctx = fc->fs_private;
        struct ext4_sb_info *sbi = fc->s_fs_info;

        sbi->s_mount_opt &= ~ctx->mask_s_mount_opt;
        sbi->s_mount_opt |= ctx->vals_s_mount_opt;
        sbi->s_mount_opt2 &= ~ctx->mask_s_mount_opt2;
        sbi->s_mount_opt2 |= ctx->vals_s_mount_opt2;
        sbi->s_mount_flags &= ~ctx->mask_s_mount_flags;
        sbi->s_mount_flags |= ctx->vals_s_mount_flags;
        sb->s_flags &= ~ctx->mask_s_flags;
        sb->s_flags |= ctx->vals_s_flags;

#define APPLY(X) ({ if (ctx->spec & EXT4_SPEC_##X) sbi->X = ctx->X; })
        APPLY(s_commit_interval);
        APPLY(s_stripe);
        APPLY(s_max_batch_time);
        APPLY(s_min_batch_time);
        APPLY(s_want_extra_isize);
        APPLY(s_inode_readahead_blks);
        APPLY(s_max_dir_size_kb);
        APPLY(s_li_wait_mult);
        APPLY(s_resgid);
        APPLY(s_resuid);

#ifdef CONFIG_EXT4_DEBUG
        APPLY(s_fc_debug_max_replay);
#endif

        ext4_apply_quota_options(fc, sb);
        ext4_apply_test_dummy_encryption(ctx, sb);
}


static int ext4_validate_options(struct fs_context *fc)
{
#ifdef CONFIG_QUOTA
        struct ext4_fs_context *ctx = fc->fs_private;
        char *usr_qf_name, *grp_qf_name;

        usr_qf_name = ctx->s_qf_names[USRQUOTA];
        grp_qf_name = ctx->s_qf_names[GRPQUOTA];

        if (usr_qf_name || grp_qf_name) {
                if (ctx_test_mount_opt(ctx, EXT4_MOUNT_USRQUOTA) && usr_qf_name)
                        ctx_clear_mount_opt(ctx, EXT4_MOUNT_USRQUOTA);

                if (ctx_test_mount_opt(ctx, EXT4_MOUNT_GRPQUOTA) && grp_qf_name)
                        ctx_clear_mount_opt(ctx, EXT4_MOUNT_GRPQUOTA);

                if (ctx_test_mount_opt(ctx, EXT4_MOUNT_USRQUOTA) ||
                    ctx_test_mount_opt(ctx, EXT4_MOUNT_GRPQUOTA)) {
                        ext4_msg(NULL, KERN_ERR, "old and new quota "
                                 "format mixing");
                        return -EINVAL;
                }
        }
#endif
        return 1;
}

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);
        char *usr_qf_name, *grp_qf_name;

        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);
        }

        rcu_read_lock();
        usr_qf_name = rcu_dereference(sbi->s_qf_names[USRQUOTA]);
        grp_qf_name = rcu_dereference(sbi->s_qf_names[GRPQUOTA]);
        if (usr_qf_name)
                seq_show_option(seq, "usrjquota", usr_qf_name);
        if (grp_qf_name)
                seq_show_option(seq, "grpjquota", grp_qf_name);
        rcu_read_unlock();
#endif
}

static const char *token2str(int token)
{
        const struct fs_parameter_spec *spec;

        for (spec = ext4_param_specs; spec->name != NULL; spec++)
                if (spec->opt == token && !spec->type)
                        break;
        return spec->name;
}

/*
 * 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 super_block *sb,
                              int nodefs)
{
        struct ext4_sb_info *sbi = EXT4_SB(sb);
        struct ext4_super_block *es = sbi->s_es;
        int def_errors;
        const struct mount_opts *m;
        char sep = nodefs ? '\n' : ',';

#define SEQ_OPTS_PUTS(str) seq_printf(seq, "%c" str, sep)
#define SEQ_OPTS_PRINT(str, arg) seq_printf(seq, "%c" str, sep, arg)

        if (sbi->s_sb_block != 1)
                SEQ_OPTS_PRINT("sb=%llu", sbi->s_sb_block);

        for (m = ext4_mount_opts; m->token != Opt_err; m++) {
                int want_set = m->flags & MOPT_SET;
                int opt_2 = m->flags & MOPT_2;
                unsigned int mount_opt, def_mount_opt;

                if (((m->flags & (MOPT_SET|MOPT_CLEAR)) == 0) ||
                    m->flags & MOPT_SKIP)
                        continue;

                if (opt_2) {
                        mount_opt = sbi->s_mount_opt2;
                        def_mount_opt = sbi->s_def_mount_opt2;
                } else {
                        mount_opt = sbi->s_mount_opt;
                        def_mount_opt = sbi->s_def_mount_opt;
                }
                /* skip if same as the default */
                if (!nodefs && !(m->mount_opt & (mount_opt ^ def_mount_opt)))
                        continue;
                /* select Opt_noFoo vs Opt_Foo */
                if ((want_set &&
                     (mount_opt & m->mount_opt) != m->mount_opt) ||
                    (!want_set && (mount_opt & m->mount_opt)))
                        continue;
                SEQ_OPTS_PRINT("%s", token2str(m->token));
        }

        if (nodefs || !uid_eq(sbi->s_resuid, make_kuid(&init_user_ns, EXT4_DEF_RESUID)) ||
            le16_to_cpu(es->s_def_resuid) != EXT4_DEF_RESUID)
                SEQ_OPTS_PRINT("resuid=%u",
                                from_kuid_munged(&init_user_ns, sbi->s_resuid));
        if (nodefs || !gid_eq(sbi->s_resgid, make_kgid(&init_user_ns, EXT4_DEF_RESGID)) ||
            le16_to_cpu(es->s_def_resgid) != EXT4_DEF_RESGID)
                SEQ_OPTS_PRINT("resgid=%u",
                                from_kgid_munged(&init_user_ns, sbi->s_resgid));
        def_errors = nodefs ? -1 : le16_to_cpu(es->s_errors);
        if (test_opt(sb, ERRORS_RO) && def_errors != EXT4_ERRORS_RO)
                SEQ_OPTS_PUTS("errors=remount-ro");
        if (test_opt(sb, ERRORS_CONT) && def_errors != EXT4_ERRORS_CONTINUE)
                SEQ_OPTS_PUTS("errors=continue");
        if (test_opt(sb, ERRORS_PANIC) && def_errors != EXT4_ERRORS_PANIC)
                SEQ_OPTS_PUTS("errors=panic");
        if (nodefs || sbi->s_commit_interval != JBD2_DEFAULT_MAX_COMMIT_AGE*HZ)
                SEQ_OPTS_PRINT("commit=%lu", sbi->s_commit_interval / HZ);
        if (nodefs || sbi->s_min_batch_time != EXT4_DEF_MIN_BATCH_TIME)
                SEQ_OPTS_PRINT("min_batch_time=%u", sbi->s_min_batch_time);
        if (nodefs || sbi->s_max_batch_time != EXT4_DEF_MAX_BATCH_TIME)
                SEQ_OPTS_PRINT("max_batch_time=%u", sbi->s_max_batch_time);
        if (nodefs || sbi->s_stripe)
                SEQ_OPTS_PRINT("stripe=%lu", sbi->s_stripe);
        if (nodefs || EXT4_MOUNT_DATA_FLAGS &
                        (sbi->s_mount_opt ^ sbi->s_def_mount_opt)) {
                if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
                        SEQ_OPTS_PUTS("data=journal");
                else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
                        SEQ_OPTS_PUTS("data=ordered");
                else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)
                        SEQ_OPTS_PUTS("data=writeback");
        }
        if (nodefs ||
            sbi->s_inode_readahead_blks != EXT4_DEF_INODE_READAHEAD_BLKS)
                SEQ_OPTS_PRINT("inode_readahead_blks=%u",
                               sbi->s_inode_readahead_blks);

        if (test_opt(sb, INIT_INODE_TABLE) && (nodefs ||
                       (sbi->s_li_wait_mult != EXT4_DEF_LI_WAIT_MULT)))
                SEQ_OPTS_PRINT("init_itable=%u", sbi->s_li_wait_mult);
        if (nodefs || sbi->s_max_dir_size_kb)
                SEQ_OPTS_PRINT("max_dir_size_kb=%u", sbi->s_max_dir_size_kb);
        if (test_opt(sb, DATA_ERR_ABORT))
                SEQ_OPTS_PUTS("data_err=abort");

        fscrypt_show_test_dummy_encryption(seq, sep, sb);

        if (sb->s_flags & SB_INLINECRYPT)
                SEQ_OPTS_PUTS("inlinecrypt");

        if (test_opt(sb, DAX_ALWAYS)) {
                if (IS_EXT2_SB(sb))
                        SEQ_OPTS_PUTS("dax");
                else
                        SEQ_OPTS_PUTS("dax=always");
        } else if (test_opt2(sb, DAX_NEVER)) {
                SEQ_OPTS_PUTS("dax=never");
        } else if (test_opt2(sb, DAX_INODE)) {
                SEQ_OPTS_PUTS("dax=inode");
        }

        if (sbi->s_groups_count >= MB_DEFAULT_LINEAR_SCAN_THRESHOLD &&
                        !test_opt2(sb, MB_OPTIMIZE_SCAN)) {
                SEQ_OPTS_PUTS("mb_optimize_scan=0");
        } else if (sbi->s_groups_count < MB_DEFAULT_LINEAR_SCAN_THRESHOLD &&
                        test_opt2(sb, MB_OPTIMIZE_SCAN)) {
                SEQ_OPTS_PUTS("mb_optimize_scan=1");
        }

        ext4_show_quota_options(seq, sb);
        return 0;
}

static int ext4_show_options(struct seq_file *seq, struct dentry *root)
{
        return _ext4_show_options(seq, root->d_sb, 0);
}

int ext4_seq_options_show(struct seq_file *seq, void *offset)
{
        struct super_block *sb = seq->private;
        int rc;

        seq_puts(seq, sb_rdonly(sb) ? "ro" : "rw");
        rc = _ext4_show_options(seq, sb, 1);
        seq_puts(seq, "\n");
        return rc;
}

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 err = 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");
                err = -EROFS;
                goto done;
        }
        if (read_only)
                goto done;
        if (!(sbi->s_mount_state & EXT4_VALID_FS))
                ext4_msg(sb, KERN_WARNING, "warning: mounting unchecked fs, "
                         "running e2fsck is recommended");
        else if (sbi->s_mount_state & EXT4_ERROR_FS)
                ext4_msg(sb, KERN_WARNING,
                         "warning: mounting fs with errors, "
                         "running e2fsck is recommended");
        else if ((__s16) le16_to_cpu(es->s_max_mnt_count) > 0 &&
                 le16_to_cpu(es->s_mnt_count) >=
                 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
                ext4_msg(sb, KERN_WARNING,
                         "warning: maximal mount count reached, "
                         "running e2fsck is recommended");
        else if (le32_to_cpu(es->s_checkinterval) &&
                 (ext4_get_tstamp(es, s_lastcheck) +
                  le32_to_cpu(es->s_checkinterval) <= ktime_get_real_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);
        ext4_update_tstamp(es, s_mtime);
        if (sbi->s_journal) {
                ext4_set_feature_journal_needs_recovery(sb);
                if (ext4_has_feature_orphan_file(sb))
                        ext4_set_feature_orphan_present(sb);
        }

        err = ext4_commit_super(sb);
done:
        if (test_opt(sb, DEBUG))
                printk(KERN_INFO "[EXT4 FS bs=%lu, gc=%u, "
                                "bpg=%lu, ipg=%lu, mo=%04x, mo2=%04x]\n",
                        sb->s_blocksize,
                        sbi->s_groups_count,
                        EXT4_BLOCKS_PER_GROUP(sb),
                        EXT4_INODES_PER_GROUP(sb),
                        sbi->s_mount_opt, sbi->s_mount_opt2);
        return err;
}

int ext4_alloc_flex_bg_array(struct super_block *sb, ext4_group_t ngroup)
{
        struct ext4_sb_info *sbi = EXT4_SB(sb);
        struct flex_groups **old_groups, **new_groups;
        int size, i, j;

        if (!sbi->s_log_groups_per_flex)
                return 0;

        size = ext4_flex_group(sbi, ngroup - 1) + 1;
        if (size <= sbi->s_flex_groups_allocated)
                return 0;

        new_groups = kvzalloc(roundup_pow_of_two(size *
                              sizeof(*sbi->s_flex_groups)), GFP_KERNEL);
        if (!new_groups) {
                ext4_msg(sb, KERN_ERR,
                         "not enough memory for %d flex group pointers", size);
                return -ENOMEM;
        }
        for (i = sbi->s_flex_groups_allocated; i < size; i++) {
                new_groups[i] = kvzalloc(roundup_pow_of_two(
                                         sizeof(struct flex_groups)),
                                         GFP_KERNEL);
                if (!new_groups[i]) {
                        for (j = sbi->s_flex_groups_allocated; j < i; j++)
                                kvfree(new_groups[j]);
                        kvfree(new_groups);
                        ext4_msg(sb, KERN_ERR,
                                 "not enough memory for %d flex groups", size);
                        return -ENOMEM;
                }
        }
        rcu_read_lock();
        old_groups = rcu_dereference(sbi->s_flex_groups);
        if (old_groups)
                memcpy(new_groups, old_groups,
                       (sbi->s_flex_groups_allocated *
                        sizeof(struct flex_groups *)));
        rcu_read_unlock();
        rcu_assign_pointer(sbi->s_flex_groups, new_groups);
        sbi->s_flex_groups_allocated = size;
        if (old_groups)
                ext4_kvfree_array_rcu(old_groups);
        return 0;
}

static int ext4_fill_flex_info(struct super_block *sb)
{
        struct ext4_sb_info *sbi = EXT4_SB(sb);
        struct ext4_group_desc *gdp = NULL;
        struct flex_groups *fg;
        ext4_group_t flex_group;
        int i, err;

        sbi->s_log_groups_per_flex = sbi->s_es->s_log_groups_per_flex;
        if (sbi->s_log_groups_per_flex < 1 || sbi->s_log_groups_per_flex > 31) {
                sbi->s_log_groups_per_flex = 0;
                return 1;
        }

        err = ext4_alloc_flex_bg_array(sb, sbi->s_groups_count);
        if (err)
                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);
                fg = sbi_array_rcu_deref(sbi, s_flex_groups, flex_group);
                atomic_add(ext4_free_inodes_count(sb, gdp), &fg->free_inodes);
                atomic64_add(ext4_free_group_clusters(sb, gdp),
                             &fg->free_clusters);
                atomic_add(ext4_used_dirs_count(sb, gdp), &fg->used_dirs);
        }

        return 1;
failed:
        return 0;
}

static __le16 ext4_group_desc_csum(struct super_block *sb, __u32 block_group,
                                   struct ext4_group_desc *gdp)
{
        int offset = offsetof(struct ext4_group_desc, bg_checksum);
        __u16 crc = 0;
        __le32 le_group = cpu_to_le32(block_group);
        struct ext4_sb_info *sbi = EXT4_SB(sb);

        if (ext4_has_metadata_csum(sbi->s_sb)) {
                /* Use new metadata_csum algorithm */
                __u32 csum32;
                __u16 dummy_csum = 0;

                csum32 = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&le_group,
                                     sizeof(le_group));
                csum32 = ext4_chksum(sbi, csum32, (__u8 *)gdp, offset);
                csum32 = ext4_chksum(sbi, csum32, (__u8 *)&dummy_csum,
                                     sizeof(dummy_csum));
                offset += sizeof(dummy_csum);
                if (offset < sbi->s_desc_size)
                        csum32 = ext4_chksum(sbi, csum32, (__u8 *)gdp + offset,
                                             sbi->s_desc_size - offset);

                crc = csum32 & 0xFFFF;
                goto out;
        }

        /* old crc16 code */
        if (!ext4_has_feature_gdt_csum(sb))
                return 0;

        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 (ext4_has_feature_64bit(sb) && offset < sbi->s_desc_size)
                crc = crc16(crc, (__u8 *)gdp + offset,
                            sbi->s_desc_size - offset);

out:
        return cpu_to_le16(crc);
}

int ext4_group_desc_csum_verify(struct super_block *sb, __u32 block_group,
                                struct ext4_group_desc *gdp)
{
        if (ext4_has_group_desc_csum(sb) &&
            (gdp->bg_checksum != ext4_group_desc_csum(sb, block_group, gdp)))
                return 0;

        return 1;
}

void ext4_group_desc_csum_set(struct super_block *sb, __u32 block_group,
                              struct ext4_group_desc *gdp)
{
        if (!ext4_has_group_desc_csum(sb))
                return;
        gdp->bg_checksum = ext4_group_desc_csum(sb, block_group, gdp);
}

/* Called at mount-time, super-block is locked */
static int ext4_check_descriptors(struct super_block *sb,
                                  ext4_fsblk_t sb_block,
                                  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 last_bg_block = sb_block + ext4_bg_num_gdb(sb, 0);
        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_feature_flex_bg(sb))
                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 == sb_block) {
                        ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
                                 "Block bitmap for group %u overlaps "
                                 "superblock", i);
                        if (!sb_rdonly(sb))
                                return 0;
                }
                if (block_bitmap >= sb_block + 1 &&
                    block_bitmap <= last_bg_block) {
                        ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
                                 "Block bitmap for group %u overlaps "
                                 "block group descriptors", i);
                        if (!sb_rdonly(sb))
                                return 0;
                }
                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 == sb_block) {
                        ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
                                 "Inode bitmap for group %u overlaps "
                                 "superblock", i);
                        if (!sb_rdonly(sb))
                                return 0;
                }
                if (inode_bitmap >= sb_block + 1 &&
                    inode_bitmap <= last_bg_block) {
                        ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
                                 "Inode bitmap for group %u overlaps "
                                 "block group descriptors", i);
                        if (!sb_rdonly(sb))
                                return 0;
                }
                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 == sb_block) {
                        ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
                                 "Inode table for group %u overlaps "
                                 "superblock", i);
                        if (!sb_rdonly(sb))
                                return 0;
                }
                if (inode_table >= sb_block + 1 &&
                    inode_table <= last_bg_block) {
                        ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
                                 "Inode table for group %u overlaps "
                                 "block group descriptors", i);
                        if (!sb_rdonly(sb))
                                return 0;
                }
                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(sb, 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(sb, i,
                                     gdp)), le16_to_cpu(gdp->bg_checksum));
                        if (!sb_rdonly(sb)) {
                                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;
        return 1;
}

/*
 * Maximal extent format file size.
 * Resulting logical blkno at s_maxbytes must fit in our on-disk
 * extent format containers, within a sector_t, and within i_blocks
 * in the vfs.  ext4 inode has 48 bits of i_block in fsblock units,
 * so that won't be a limiting factor.
 *
 * However there is other limiting factor. We do store extents in the form
 * of starting block and length, hence the resulting length of the extent
 * covering maximum file size must fit into on-disk format containers as
 * well. Given that length is always by 1 unit bigger than max unit (because
 * we count 0 as well) we have to lower the s_maxbytes by one fs block.
 *
 * Note, this does *not* consider any metadata overhead for vfs i_blocks.
 */
static loff_t ext4_max_size(int blkbits, int has_huge_files)
{
        loff_t res;
        loff_t upper_limit = MAX_LFS_FILESIZE;

        BUILD_BUG_ON(sizeof(blkcnt_t) < sizeof(u64));

        if (!has_huge_files) {
                upper_limit = (1LL << 32) - 1;

                /* total blocks in file system block size */
                upper_limit >>= (blkbits - 9);
                upper_limit <<= blkbits;
        }

        /*
         * 32-bit extent-start container, ee_block. We lower the maxbytes
         * by one fs block, so ee_len can cover the extent of maximum file
         * size
         */
        res = (1LL << 32) - 1;
        res <<= blkbits;

        /* Sanity check against vm- & vfs- imposed limits */
        if (res > upper_limit)
                res = upper_limit;

        return res;
}

/*
 * Maximal bitmap file size.  There is a direct, and {,double-,triple-}indirect
 * block limit, and also a limit of (2^48 - 1) 512-byte sectors in i_blocks.
 * We need to be 1 filesystem block less than the 2^48 sector limit.
 */
static loff_t ext4_max_bitmap_size(int bits, int has_huge_files)
{
        loff_t upper_limit, res = EXT4_NDIR_BLOCKS;
        int meta_blocks;
        unsigned int ppb = 1 << (bits - 2);

        /*
         * 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) {
                /*
                 * !has_huge_files or 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;

        }

        /* Compute how many blocks we can address by block tree */
        res += ppb;
        res += ppb * ppb;
        res += ((loff_t)ppb) * ppb * ppb;
        /* Compute how many metadata blocks are needed */
        meta_blocks = 1;
        meta_blocks += 1 + ppb;
        meta_blocks += 1 + ppb + ppb * ppb;
        /* Does block tree limit file size? */
        if (res + meta_blocks <= upper_limit)
                goto check_lfs;

        res = upper_limit;
        /* How many metadata blocks are needed for addressing upper_limit? */
        upper_limit -= EXT4_NDIR_BLOCKS;
        /* indirect blocks */
        meta_blocks = 1;
        upper_limit -= ppb;
        /* double indirect blocks */
        if (upper_limit < ppb * ppb) {
                meta_blocks += 1 + DIV_ROUND_UP_ULL(upper_limit, ppb);
                res -= meta_blocks;
                goto check_lfs;
        }
        meta_blocks += 1 + ppb;
        upper_limit -= ppb * ppb;
        /* tripple indirect blocks for the rest */
        meta_blocks += 1 + DIV_ROUND_UP_ULL(upper_limit, ppb) +
                DIV_ROUND_UP_ULL(upper_limit, ppb*ppb);
        res -= meta_blocks;
check_lfs:
        res <<= bits;
        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_feature_meta_bg(sb) || 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;

        /*
         * If we have a meta_bg fs with 1k blocks, group 0's GDT is at
         * block 2, not 1.  If s_first_data_block == 0 (bigalloc is enabled
         * on modern mke2fs or blksize > 1k on older mke2fs) then we must
         * compensate.
         */
        if (sb->s_blocksize == 1024 && nr == 0 &&
            le32_to_cpu(sbi->s_es->s_first_data_block) == 0)
                has_super++;

        return (has_super + ext4_group_first_block_no(sb, bg));
}

/**
 * ext4_get_stripe_size: Get the stripe size.
 * @sbi: In memory super block info
 *
 * If we have specified it via mount option, then
 * use the mount option value. If the value specified at mount time is
 * greater than the blocks per group use the super block value.
 * If the super block value is greater than blocks per group return 0.
 * Allocator needs it be less than blocks per group.
 *
 */
static unsigned long ext4_get_stripe_size(struct ext4_sb_info *sbi)
{
        unsigned long stride = le16_to_cpu(sbi->s_es->s_raid_stride);
        unsigned long stripe_width =
                        le32_to_cpu(sbi->s_es->s_raid_stripe_width);
        int ret;

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

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

        return ret;
}

/*
 * 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.
 */
int ext4_feature_set_ok(struct super_block *sb, int readonly)
{
        if (ext4_has_unknown_ext4_incompat_features(sb)) {
                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 !IS_ENABLED(CONFIG_UNICODE)
        if (ext4_has_feature_casefold(sb)) {
                ext4_msg(sb, KERN_ERR,
                         "Filesystem with casefold feature cannot be "
                         "mounted without CONFIG_UNICODE");
                return 0;
        }
#endif

        if (readonly)
                return 1;

        if (ext4_has_feature_readonly(sb)) {
                ext4_msg(sb, KERN_INFO, "filesystem is read-only");
                sb->s_flags |= SB_RDONLY;
                return 1;
        }

        /* Check that feature set is OK for a read-write mount */
        if (ext4_has_unknown_ext4_ro_compat_features(sb)) {
                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;
        }
        if (ext4_has_feature_bigalloc(sb) && !ext4_has_feature_extents(sb)) {
                ext4_msg(sb, KERN_ERR,
                         "Can't support bigalloc feature without "
                         "extents feature\n");
                return 0;
        }

#if !IS_ENABLED(CONFIG_QUOTA) || !IS_ENABLED(CONFIG_QFMT_V2)
        if (!readonly && (ext4_has_feature_quota(sb) ||
                          ext4_has_feature_project(sb))) {
                ext4_msg(sb, KERN_ERR,
                         "The kernel was not built with CONFIG_QUOTA and CONFIG_QFMT_V2");
                return 0;
        }
#endif  /* CONFIG_QUOTA */
        return 1;
}

/*
 * This function is called once a day if we have errors logged
 * on the file system
 */
static void print_daily_error_info(struct timer_list *t)
{
        struct ext4_sb_info *sbi = from_timer(sbi, t, s_err_report);
        struct super_block *sb = sbi->s_sb;
        struct ext4_super_block *es = sbi->s_es;

        if (es->s_error_count)
                /* fsck newer than v1.41.13 is needed to clean this condition. */
                ext4_msg(sb, KERN_NOTICE, "error count since last fsck: %u",
                         le32_to_cpu(es->s_error_count));
        if (es->s_first_error_time) {
                printk(KERN_NOTICE "EXT4-fs (%s): initial error at time %llu: %.*s:%d",
                       sb->s_id,
                       ext4_get_tstamp(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(KERN_CONT ": inode %u",
                               le32_to_cpu(es->s_first_error_ino));
                if (es->s_first_error_block)
                        printk(KERN_CONT ": block %llu", (unsigned long long)
                               le64_to_cpu(es->s_first_error_block));
                printk(KERN_CONT "\n");
        }
        if (es->s_last_error_time) {
                printk(KERN_NOTICE "EXT4-fs (%s): last error at time %llu: %.*s:%d",
                       sb->s_id,
                       ext4_get_tstamp(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(KERN_CONT ": inode %u",
                               le32_to_cpu(es->s_last_error_ino));
                if (es->s_last_error_block)
                        printk(KERN_CONT ": block %llu", (unsigned long long)
                               le64_to_cpu(es->s_last_error_block));
                printk(KERN_CONT "\n");
        }
        mod_timer(&sbi->s_err_report, jiffies + 24*60*60*HZ);  /* Once a day */
}

/* Find next suitable group and run ext4_init_inode_table */
static int ext4_run_li_request(struct ext4_li_request *elr)
{
        struct ext4_group_desc *gdp = NULL;
        struct super_block *sb = elr->lr_super;
        ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
        ext4_group_t group = elr->lr_next_group;
        unsigned int prefetch_ios = 0;
        int ret = 0;
        u64 start_time;

        if (elr->lr_mode == EXT4_LI_MODE_PREFETCH_BBITMAP) {
                elr->lr_next_group = ext4_mb_prefetch(sb, group,
                                EXT4_SB(sb)->s_mb_prefetch, &prefetch_ios);
                if (prefetch_ios)
                        ext4_mb_prefetch_fini(sb, elr->lr_next_group,
                                              prefetch_ios);
                trace_ext4_prefetch_bitmaps(sb, group, elr->lr_next_group,
                                            prefetch_ios);
                if (group >= elr->lr_next_group) {
                        ret = 1;
                        if (elr->lr_first_not_zeroed != ngroups &&
                            !sb_rdonly(sb) && test_opt(sb, INIT_INODE_TABLE)) {
                                elr->lr_next_group = elr->lr_first_not_zeroed;
                                elr->lr_mode = EXT4_LI_MODE_ITABLE;
                                ret = 0;
                        }
                }
                return ret;
        }

        for (; 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) {
                start_time = ktime_get_real_ns();
                ret = ext4_init_inode_table(sb, group,
                                            elr->lr_timeout ? 0 : 1);
                trace_ext4_lazy_itable_init(sb, group);
                if (elr->lr_timeout == 0) {
                        elr->lr_timeout = nsecs_to_jiffies((ktime_get_real_ns() - start_time) *
                                EXT4_SB(elr->lr_super)->s_li_wait_mult);
                }
                elr->lr_next_sched = jiffies + elr->lr_timeout;
                elr->lr_next_group = group + 1;
        }
        return ret;
}

/*
 * Remove lr_request from the list_request and free the
 * request structure. Should be called with li_list_mtx held
 */
static void ext4_remove_li_request(struct ext4_li_request *elr)
{
        if (!elr)
                return;

        list_del(&elr->lr_request);
        EXT4_SB(elr->lr_super)->s_li_request = NULL;
        kfree(elr);
}

static void ext4_unregister_li_request(struct super_block *sb)
{
        mutex_lock(&ext4_li_mtx);
        if (!ext4_li_info) {
                mutex_unlock(&ext4_li_mtx);
                return;
        }

        mutex_lock(&ext4_li_info->li_list_mtx);
        ext4_remove_li_request(EXT4_SB(sb)->s_li_request);
        mutex_unlock(&ext4_li_info->li_list_mtx);
        mutex_unlock(&ext4_li_mtx);
}

static struct task_struct *ext4_lazyinit_task;

/*
 * This is the function where ext4lazyinit thread lives. It walks
 * through the request list searching for next scheduled filesystem.
 * When such a fs is found, run the lazy initialization request
 * (ext4_rn_li_request) and keep track of the time spend in this
 * function. Based on that time we compute next schedule time of
 * the request. When walking through the list is complete, compute
 * next waking time and put itself into sleep.
 */
static int ext4_lazyinit_thread(void *arg)
{
        struct ext4_lazy_init *eli = arg;
        struct list_head *pos, *n;
        struct ext4_li_request *elr;
        unsigned long next_wakeup, cur;

        BUG_ON(NULL == eli);
        set_freezable();

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) {
                        int err = 0;
                        int progress = 0;
                        elr = list_entry(pos, struct ext4_li_request,
                                         lr_request);

                        if (time_before(jiffies, elr->lr_next_sched)) {
                                if (time_before(elr->lr_next_sched, next_wakeup))
                                        next_wakeup = elr->lr_next_sched;
                                continue;
                        }
                        if (down_read_trylock(&elr->lr_super->s_umount)) {
                                if (sb_start_write_trylock(elr->lr_super)) {
                                        progress = 1;
                                        /*
                                         * We hold sb->s_umount, sb can not
                                         * be removed from the list, it is
                                         * now safe to drop li_list_mtx
                                         */
                                        mutex_unlock(&eli->li_list_mtx);
                                        err = ext4_run_li_request(elr);
                                        sb_end_write(elr->lr_super);
                                        mutex_lock(&eli->li_list_mtx);
                                        n = pos->next;
                                }
                                up_read((&elr->lr_super->s_umount));
                        }
                        /* error, remove the lazy_init job */
                        if (err) {
                                ext4_remove_li_request(elr);
                                continue;
                        }
                        if (!progress) {
                                elr->lr_next_sched = jiffies +
                                        get_random_u32_below(EXT4_DEF_LI_MAX_START_DELAY * HZ);
                        }
                        if (time_before(elr->lr_next_sched, next_wakeup))
                                next_wakeup = elr->lr_next_sched;
                }
                mutex_unlock(&eli->li_list_mtx);

                try_to_freeze();

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

                schedule_timeout_interruptible(next_wakeup - cur);

                if (kthread_should_stop()) {
                        ext4_clear_request_list();
                        goto exit_thread;
                }
        }

exit_thread:
        /*
         * It looks like the request list is empty, but we need
         * to check it under the li_list_mtx lock, to prevent any
         * additions into it, and of course we should lock ext4_li_mtx
         * to atomically free the list and ext4_li_info, because at
         * this point another ext4 filesystem could be registering
         * new one.
         */
        mutex_lock(&ext4_li_mtx);
        mutex_lock(&eli->li_list_mtx);
        if (!list_empty(&eli->li_request_list)) {
                mutex_unlock(&eli->li_list_mtx);
                mutex_unlock(&ext4_li_mtx);
                goto cont_thread;
        }
        mutex_unlock(&eli->li_list_mtx);
        kfree(ext4_li_info);
        ext4_li_info = NULL;
        mutex_unlock(&ext4_li_mtx);

        return 0;
}

static void ext4_clear_request_list(void)
{
        struct list_head *pos, *n;
        struct ext4_li_request *elr;

        mutex_lock(&ext4_li_info->li_list_mtx);
        list_for_each_safe(pos, n, &ext4_li_info->li_request_list) {
                elr = list_entry(pos, struct ext4_li_request,
                                 lr_request);
                ext4_remove_li_request(elr);
        }
        mutex_unlock(&ext4_li_info->li_list_mtx);
}

static int ext4_run_lazyinit_thread(void)
{
        ext4_lazyinit_task = kthread_run(ext4_lazyinit_thread,
                                         ext4_li_info, "ext4lazyinit");
        if (IS_ERR(ext4_lazyinit_task)) {
                int err = PTR_ERR(ext4_lazyinit_task);
                ext4_clear_request_list();
                kfree(ext4_li_info);
                ext4_li_info = NULL;
                printk(KERN_CRIT "EXT4-fs: error %d creating inode table "
                                 "initialization thread\n",
                                 err);
                return err;
        }
        ext4_li_info->li_state |= EXT4_LAZYINIT_RUNNING;
        return 0;
}

/*
 * Check whether it make sense to run itable init. thread or not.
 * If there is at least one uninitialized inode table, return
 * corresponding group number, else the loop goes through all
 * groups and return total number of groups.
 */
static ext4_group_t ext4_has_uninit_itable(struct super_block *sb)
{
        ext4_group_t group, ngroups = EXT4_SB(sb)->s_groups_count;
        struct ext4_group_desc *gdp = NULL;

        if (!ext4_has_group_desc_csum(sb))
                return ngroups;

        for (group = 0; group < ngroups; group++) {
                gdp = ext4_get_group_desc(sb, group, NULL);
                if (!gdp)
                        continue;

                if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
                        break;
        }

        return group;
}

static int ext4_li_info_new(void)
{
        struct ext4_lazy_init *eli = NULL;

        eli = kzalloc(sizeof(*eli), GFP_KERNEL);
        if (!eli)
                return -ENOMEM;

        INIT_LIST_HEAD(&eli->li_request_list);
        mutex_init(&eli->li_list_mtx);

        eli->li_state |= EXT4_LAZYINIT_QUIT;

        ext4_li_info = eli;

        return 0;
}

static struct ext4_li_request *ext4_li_request_new(struct super_block *sb,
                                            ext4_group_t start)
{
        struct ext4_li_request *elr;

        elr = kzalloc(sizeof(*elr), GFP_KERNEL);
        if (!elr)
                return NULL;

        elr->lr_super = sb;
        elr->lr_first_not_zeroed = start;
        if (test_opt(sb, NO_PREFETCH_BLOCK_BITMAPS)) {
                elr->lr_mode = EXT4_LI_MODE_ITABLE;
                elr->lr_next_group = start;
        } else {
                elr->lr_mode = EXT4_LI_MODE_PREFETCH_BBITMAP;
        }

        /*
         * Randomize first schedule time of the request to
         * spread the inode table initialization requests
         * better.
         */
        elr->lr_next_sched = jiffies + get_random_u32_below(EXT4_DEF_LI_MAX_START_DELAY * HZ);
        return elr;
}

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 = NULL;
        ext4_group_t ngroups = sbi->s_groups_count;
        int ret = 0;

        mutex_lock(&ext4_li_mtx);
        if (sbi->s_li_request != NULL) {
                /*
                 * Reset timeout so it can be computed again, because
                 * s_li_wait_mult might have changed.
                 */
                sbi->s_li_request->lr_timeout = 0;
                goto out;
        }

        if (sb_rdonly(sb) ||
            (test_opt(sb, NO_PREFETCH_BLOCK_BITMAPS) &&
             (first_not_zeroed == ngroups || !test_opt(sb, INIT_INODE_TABLE))))
                goto out;

        elr = ext4_li_request_new(sb, first_not_zeroed);
        if (!elr) {
                ret = -ENOMEM;
                goto out;
        }

        if (NULL == ext4_li_info) {
                ret = ext4_li_info_new();
                if (ret)
                        goto out;
        }

        mutex_lock(&ext4_li_info->li_list_mtx);
        list_add(&elr->lr_request, &ext4_li_info->li_request_list);
        mutex_unlock(&ext4_li_info->li_list_mtx);

        sbi->s_li_request = elr;
        /*
         * set elr to NULL here since it has been inserted to
         * the request_list and the removal and free of it is
         * handled by ext4_clear_request_list from now on.
         */
        elr = NULL;

        if (!(ext4_li_info->li_state & EXT4_LAZYINIT_RUNNING)) {
                ret = ext4_run_lazyinit_thread();
                if (ret)
                        goto out;
        }
out:
        mutex_unlock(&ext4_li_mtx);
        if (ret)
                kfree(elr);
        return ret;
}

/*
 * We do not need to lock anything since this is called on
 * module unload.
 */
static void ext4_destroy_lazyinit_thread(void)
{
        /*
         * If thread exited earlier
         * there's nothing to be done.
         */
        if (!ext4_li_info || !ext4_lazyinit_task)
                return;

        kthread_stop(ext4_lazyinit_task);
}

static int set_journal_csum_feature_set(struct super_block *sb)
{
        int ret = 1;
        int compat, incompat;
        struct ext4_sb_info *sbi = EXT4_SB(sb);

        if (ext4_has_metadata_csum(sb)) {
                /* journal checksum v3 */
                compat = 0;
                incompat = JBD2_FEATURE_INCOMPAT_CSUM_V3;
        } else {
                /* journal checksum v1 */
                compat = JBD2_FEATURE_COMPAT_CHECKSUM;
                incompat = 0;
        }

        jbd2_journal_clear_features(sbi->s_journal,
                        JBD2_FEATURE_COMPAT_CHECKSUM, 0,
                        JBD2_FEATURE_INCOMPAT_CSUM_V3 |
                        JBD2_FEATURE_INCOMPAT_CSUM_V2);
        if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
                ret = jbd2_journal_set_features(sbi->s_journal,
                                compat, 0,
                                JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT |
                                incompat);
        } else if (test_opt(sb, JOURNAL_CHECKSUM)) {
                ret = jbd2_journal_set_features(sbi->s_journal,
                                compat, 0,
                                incompat);
                jbd2_journal_clear_features(sbi->s_journal, 0, 0,
                                JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
        } else {
                jbd2_journal_clear_features(sbi->s_journal, 0, 0,
                                JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
        }

        return ret;
}

/*
 * Note: calculating the overhead so we can be compatible with
 * historical BSD practice is quite difficult in the face of
 * clusters/bigalloc.  This is because multiple metadata blocks from
 * different block group can end up in the same allocation cluster.
 * Calculating the exact overhead in the face of clustered allocation
 * requires either O(all block bitmaps) in memory or O(number of block
 * groups**2) in time.  We will still calculate the superblock for
 * older file systems --- and if we come across with a bigalloc file
 * system with zero in s_overhead_clusters the estimate will be close to
 * correct especially for very large cluster sizes --- but for newer
 * file systems, it's better to calculate this figure once at mkfs
 * time, and store it in the superblock.  If the superblock value is
 * present (even for non-bigalloc file systems), we will use it.
 */
static int count_overhead(struct super_block *sb, ext4_group_t grp,
                          char *buf)
{
        struct ext4_sb_info     *sbi = EXT4_SB(sb);
        struct ext4_group_desc  *gdp;
        ext4_fsblk_t            first_block, last_block, b;
        ext4_group_t            i, ngroups = ext4_get_groups_count(sb);
        int                     s, j, count = 0;
        int                     has_super = ext4_bg_has_super(sb, grp);

        if (!ext4_has_feature_bigalloc(sb))
                return (has_super + ext4_bg_num_gdb(sb, grp) +
                        (has_super ? le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) : 0) +
                        sbi->s_itb_per_group + 2);

        first_block = le32_to_cpu(sbi->s_es->s_first_data_block) +
                (grp * EXT4_BLOCKS_PER_GROUP(sb));
        last_block = first_block + EXT4_BLOCKS_PER_GROUP(sb) - 1;
        for (i = 0; i < ngroups; i++) {
                gdp = ext4_get_group_desc(sb, i, NULL);
                b = ext4_block_bitmap(sb, gdp);
                if (b >= first_block && b <= last_block) {
                        ext4_set_bit(EXT4_B2C(sbi, b - first_block), buf);
                        count++;
                }
                b = ext4_inode_bitmap(sb, gdp);
                if (b >= first_block && b <= last_block) {
                        ext4_set_bit(EXT4_B2C(sbi, b - first_block), buf);
                        count++;
                }
                b = ext4_inode_table(sb, gdp);
                if (b >= first_block && b + sbi->s_itb_per_group <= last_block)
                        for (j = 0; j < sbi->s_itb_per_group; j++, b++) {
                                int c = EXT4_B2C(sbi, b - first_block);
                                ext4_set_bit(c, buf);
                                count++;
                        }
                if (i != grp)
                        continue;
                s = 0;
                if (ext4_bg_has_super(sb, grp)) {
                        ext4_set_bit(s++, buf);
                        count++;
                }
                j = ext4_bg_num_gdb(sb, grp);
                if (s + j > EXT4_BLOCKS_PER_GROUP(sb)) {
                        ext4_error(sb, "Invalid number of block group "
                                   "descriptor blocks: %d", j);
                        j = EXT4_BLOCKS_PER_GROUP(sb) - s;
                }
                count += j;
                for (; j > 0; j--)
                        ext4_set_bit(EXT4_B2C(sbi, s++), buf);
        }
        if (!count)
                return 0;
        return EXT4_CLUSTERS_PER_GROUP(sb) -
                ext4_count_free(buf, EXT4_CLUSTERS_PER_GROUP(sb) / 8);
}

/*
 * Compute the overhead and stash it in sbi->s_overhead
 */
int ext4_calculate_overhead(struct super_block *sb)
{
        struct ext4_sb_info *sbi = EXT4_SB(sb);
        struct ext4_super_block *es = sbi->s_es;
        struct inode *j_inode;
        unsigned int j_blocks, j_inum = le32_to_cpu(es->s_journal_inum);
        ext4_group_t i, ngroups = ext4_get_groups_count(sb);
        ext4_fsblk_t overhead = 0;
        char *buf = (char *) get_zeroed_page(GFP_NOFS);

        if (!buf)
                return -ENOMEM;

        /*
         * Compute the overhead (FS structures).  This is constant
         * for a given filesystem unless the number of block groups
         * changes so we cache the previous value until it does.
         */

        /*
         * All of the blocks before first_data_block are overhead
         */
        overhead = EXT4_B2C(sbi, le32_to_cpu(es->s_first_data_block));

        /*
         * Add the overhead found in each block group
         */
        for (i = 0; i < ngroups; i++) {
                int blks;

                blks = count_overhead(sb, i, buf);
                overhead += blks;
                if (blks)
                        memset(buf, 0, PAGE_SIZE);
                cond_resched();
        }

        /*
         * Add the internal journal blocks whether the journal has been
         * loaded or not
         */
        if (sbi->s_journal && !sbi->s_journal_bdev)
                overhead += EXT4_NUM_B2C(sbi, sbi->s_journal->j_total_len);
        else if (ext4_has_feature_journal(sb) && !sbi->s_journal && j_inum) {
                /* j_inum for internal journal is non-zero */
                j_inode = ext4_get_journal_inode(sb, j_inum);
                if (j_inode) {
                        j_blocks = j_inode->i_size >> sb->s_blocksize_bits;
                        overhead += EXT4_NUM_B2C(sbi, j_blocks);
                        iput(j_inode);
                } else {
                        ext4_msg(sb, KERN_ERR, "can't get journal size");
                }
        }
        sbi->s_overhead = overhead;
        smp_wmb();
        free_page((unsigned long) buf);
        return 0;
}

static void ext4_set_resv_clusters(struct super_block *sb)
{
        ext4_fsblk_t resv_clusters;
        struct ext4_sb_info *sbi = EXT4_SB(sb);

        /*
         * There's no need to reserve anything when we aren't using extents.
         * The space estimates are exact, there are no unwritten extents,
         * hole punching doesn't need new metadata... This is needed especially
         * to keep ext2/3 backward compatibility.
         */
        if (!ext4_has_feature_extents(sb))
                return;
        /*
         * By default we reserve 2% or 4096 clusters, whichever is smaller.
         * This should cover the situations where we can not afford to run
         * out of space like for example punch hole, or converting
         * unwritten extents in delalloc path. In most cases such
         * allocation would require 1, or 2 blocks, higher numbers are
         * very rare.
         */
        resv_clusters = (ext4_blocks_count(sbi->s_es) >>
                         sbi->s_cluster_bits);

        do_div(resv_clusters, 50);
        resv_clusters = min_t(ext4_fsblk_t, resv_clusters, 4096);

        atomic64_set(&sbi->s_resv_clusters, resv_clusters);
}

static const char *ext4_quota_mode(struct super_block *sb)
{
#ifdef CONFIG_QUOTA
        if (!ext4_quota_capable(sb))
                return "none";

        if (EXT4_SB(sb)->s_journal && ext4_is_quota_journalled(sb))
                return "journalled";
        else
                return "writeback";
#else
        return "disabled";
#endif
}

static void ext4_setup_csum_trigger(struct super_block *sb,
                                    enum ext4_journal_trigger_type type,
                                    void (*trigger)(
                                        struct jbd2_buffer_trigger_type *type,
                                        struct buffer_head *bh,
                                        void *mapped_data,
                                        size_t size))
{
        struct ext4_sb_info *sbi = EXT4_SB(sb);

        sbi->s_journal_triggers[type].sb = sb;
        sbi->s_journal_triggers[type].tr_triggers.t_frozen = trigger;
}

static void ext4_free_sbi(struct ext4_sb_info *sbi)
{
        if (!sbi)
                return;

        kfree(sbi->s_blockgroup_lock);
        fs_put_dax(sbi->s_daxdev, NULL);
        kfree(sbi);
}

static struct ext4_sb_info *ext4_alloc_sbi(struct super_block *sb)
{
        struct ext4_sb_info *sbi;

        sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
        if (!sbi)
                return NULL;

        sbi->s_daxdev = fs_dax_get_by_bdev(sb->s_bdev, &sbi->s_dax_part_off,
                                           NULL, NULL);

        sbi->s_blockgroup_lock =
                kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);

        if (!sbi->s_blockgroup_lock)
                goto err_out;

        sb->s_fs_info = sbi;
        sbi->s_sb = sb;
        return sbi;
err_out:
        fs_put_dax(sbi->s_daxdev, NULL);
        kfree(sbi);
        return NULL;
}

static void ext4_set_def_opts(struct super_block *sb,
                              struct ext4_super_block *es)
{
        unsigned long def_mount_opts;

        /* Set defaults before we parse the mount options */
        def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
        set_opt(sb, INIT_INODE_TABLE);
        if (def_mount_opts & EXT4_DEFM_DEBUG)
                set_opt(sb, DEBUG);
        if (def_mount_opts & EXT4_DEFM_BSDGROUPS)
                set_opt(sb, GRPID);
        if (def_mount_opts & EXT4_DEFM_UID16)
                set_opt(sb, NO_UID32);
        /* xattr user namespace & acls are now defaulted on */
        set_opt(sb, XATTR_USER);
#ifdef CONFIG_EXT4_FS_POSIX_ACL
        set_opt(sb, POSIX_ACL);
#endif
        if (ext4_has_feature_fast_commit(sb))
                set_opt2(sb, JOURNAL_FAST_COMMIT);
        /* don't forget to enable journal_csum when metadata_csum is enabled. */
        if (ext4_has_metadata_csum(sb))
                set_opt(sb, JOURNAL_CHECKSUM);

        if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_DATA)
                set_opt(sb, JOURNAL_DATA);
        else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_ORDERED)
                set_opt(sb, ORDERED_DATA);
        else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_WBACK)
                set_opt(sb, WRITEBACK_DATA);

        if (le16_to_cpu(es->s_errors) == EXT4_ERRORS_PANIC)
                set_opt(sb, ERRORS_PANIC);
        else if (le16_to_cpu(es->s_errors) == EXT4_ERRORS_CONTINUE)
                set_opt(sb, ERRORS_CONT);
        else
                set_opt(sb, ERRORS_RO);
        /* block_validity enabled by default; disable with noblock_validity */
        set_opt(sb, BLOCK_VALIDITY);
        if (def_mount_opts & EXT4_DEFM_DISCARD)
                set_opt(sb, DISCARD);

        if ((def_mount_opts & EXT4_DEFM_NOBARRIER) == 0)
                set_opt(sb, BARRIER);

        /*
         * enable delayed allocation by default
         * Use -o nodelalloc to turn it off
         */
        if (!IS_EXT3_SB(sb) && !IS_EXT2_SB(sb) &&
            ((def_mount_opts & EXT4_DEFM_NODELALLOC) == 0))
                set_opt(sb, DELALLOC);

        if (sb->s_blocksize == PAGE_SIZE)
                set_opt(sb, DIOREAD_NOLOCK);
}

static int ext4_handle_clustersize(struct super_block *sb)
{
        struct ext4_sb_info *sbi = EXT4_SB(sb);
        struct ext4_super_block *es = sbi->s_es;
        int clustersize;

        /* Handle clustersize */
        clustersize = BLOCK_SIZE << le32_to_cpu(es->s_log_cluster_size);
        if (ext4_has_feature_bigalloc(sb)) {
                if (clustersize < sb->s_blocksize) {
                        ext4_msg(sb, KERN_ERR,
                                 "cluster size (%d) smaller than "
                                 "block size (%lu)", clustersize, sb->s_blocksize);
                        return -EINVAL;
                }
                sbi->s_cluster_bits = le32_to_cpu(es->s_log_cluster_size) -
                        le32_to_cpu(es->s_log_block_size);
                sbi->s_clusters_per_group =
                        le32_to_cpu(es->s_clusters_per_group);
                if (sbi->s_clusters_per_group > sb->s_blocksize * 8) {
                        ext4_msg(sb, KERN_ERR,
                                 "#clusters per group too big: %lu",
                                 sbi->s_clusters_per_group);
                        return -EINVAL;
                }
                if (sbi->s_blocks_per_group !=
                    (sbi->s_clusters_per_group * (clustersize / sb->s_blocksize))) {
                        ext4_msg(sb, KERN_ERR, "blocks per group (%lu) and "
                                 "clusters per group (%lu) inconsistent",
                                 sbi->s_blocks_per_group,
                                 sbi->s_clusters_per_group);
                        return -EINVAL;
                }
        } else {
                if (clustersize != sb->s_blocksize) {
                        ext4_msg(sb, KERN_ERR,
                                 "fragment/cluster size (%d) != "
                                 "block size (%lu)", clustersize, sb->s_blocksize);
                        return -EINVAL;
                }
                if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
                        ext4_msg(sb, KERN_ERR,
                                 "#blocks per group too big: %lu",
                                 sbi->s_blocks_per_group);
                        return -EINVAL;
                }
                sbi->s_clusters_per_group = sbi->s_blocks_per_group;
                sbi->s_cluster_bits = 0;
        }
        sbi->s_cluster_ratio = clustersize / sb->s_blocksize;

        /* Do we have standard group size of clustersize * 8 blocks ? */
        if (sbi->s_blocks_per_group == clustersize << 3)
                set_opt2(sb, STD_GROUP_SIZE);

        return 0;
}

static void ext4_fast_commit_init(struct super_block *sb)
{
        struct ext4_sb_info *sbi = EXT4_SB(sb);

        /* Initialize fast commit stuff */
        atomic_set(&sbi->s_fc_subtid, 0);
        INIT_LIST_HEAD(&sbi->s_fc_q[FC_Q_MAIN]);
        INIT_LIST_HEAD(&sbi->s_fc_q[FC_Q_STAGING]);
        INIT_LIST_HEAD(&sbi->s_fc_dentry_q[FC_Q_MAIN]);
        INIT_LIST_HEAD(&sbi->s_fc_dentry_q[FC_Q_STAGING]);
        sbi->s_fc_bytes = 0;
        ext4_clear_mount_flag(sb, EXT4_MF_FC_INELIGIBLE);
        sbi->s_fc_ineligible_tid = 0;
        spin_lock_init(&sbi->s_fc_lock);
        memset(&sbi->s_fc_stats, 0, sizeof(sbi->s_fc_stats));
        sbi->s_fc_replay_state.fc_regions = NULL;
        sbi->s_fc_replay_state.fc_regions_size = 0;
        sbi->s_fc_replay_state.fc_regions_used = 0;
        sbi->s_fc_replay_state.fc_regions_valid = 0;
        sbi->s_fc_replay_state.fc_modified_inodes = NULL;
        sbi->s_fc_replay_state.fc_modified_inodes_size = 0;
        sbi->s_fc_replay_state.fc_modified_inodes_used = 0;
}

static int ext4_inode_info_init(struct super_block *sb,
                                struct ext4_super_block *es)
{
        struct ext4_sb_info *sbi = EXT4_SB(sb);

        if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV) {
                sbi->s_inode_size = EXT4_GOOD_OLD_INODE_SIZE;
                sbi->s_first_ino = EXT4_GOOD_OLD_FIRST_INO;
        } else {
                sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
                sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
                if (sbi->s_first_ino < EXT4_GOOD_OLD_FIRST_INO) {
                        ext4_msg(sb, KERN_ERR, "invalid first ino: %u",
                                 sbi->s_first_ino);
                        return -EINVAL;
                }
                if ((sbi->s_inode_size < EXT4_GOOD_OLD_INODE_SIZE) ||
                    (!is_power_of_2(sbi->s_inode_size)) ||
                    (sbi->s_inode_size > sb->s_blocksize)) {
                        ext4_msg(sb, KERN_ERR,
                               "unsupported inode size: %d",
                               sbi->s_inode_size);
                        ext4_msg(sb, KERN_ERR, "blocksize: %lu", sb->s_blocksize);
                        return -EINVAL;
                }
                /*
                 * i_atime_extra is the last extra field available for
                 * [acm]times in struct ext4_inode. Checking for that
                 * field should suffice to ensure we have extra space
                 * for all three.
                 */
                if (sbi->s_inode_size >= offsetof(struct ext4_inode, i_atime_extra) +
                        sizeof(((struct ext4_inode *)0)->i_atime_extra)) {
                        sb->s_time_gran = 1;
                        sb->s_time_max = EXT4_EXTRA_TIMESTAMP_MAX;
                } else {
                        sb->s_time_gran = NSEC_PER_SEC;
                        sb->s_time_max = EXT4_NON_EXTRA_TIMESTAMP_MAX;
                }
                sb->s_time_min = EXT4_TIMESTAMP_MIN;
        }

        if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
                sbi->s_want_extra_isize = sizeof(struct ext4_inode) -
                        EXT4_GOOD_OLD_INODE_SIZE;
                if (ext4_has_feature_extra_isize(sb)) {
                        unsigned v, max = (sbi->s_inode_size -
                                           EXT4_GOOD_OLD_INODE_SIZE);

                        v = le16_to_cpu(es->s_want_extra_isize);
                        if (v > max) {
                                ext4_msg(sb, KERN_ERR,
                                         "bad s_want_extra_isize: %d", v);
                                return -EINVAL;
                        }
                        if (sbi->s_want_extra_isize < v)
                                sbi->s_want_extra_isize = v;

                        v = le16_to_cpu(es->s_min_extra_isize);
                        if (v > max) {
                                ext4_msg(sb, KERN_ERR,
                                         "bad s_min_extra_isize: %d", v);
                                return -EINVAL;
                        }
                        if (sbi->s_want_extra_isize < v)
                                sbi->s_want_extra_isize = v;
                }
        }

        return 0;
}

#if IS_ENABLED(CONFIG_UNICODE)
static int ext4_encoding_init(struct super_block *sb, struct ext4_super_block *es)
{
        const struct ext4_sb_encodings *encoding_info;
        struct unicode_map *encoding;
        __u16 encoding_flags = le16_to_cpu(es->s_encoding_flags);

        if (!ext4_has_feature_casefold(sb) || sb->s_encoding)
                return 0;

        encoding_info = ext4_sb_read_encoding(es);
        if (!encoding_info) {
                ext4_msg(sb, KERN_ERR,
                        "Encoding requested by superblock is unknown");
                return -EINVAL;
        }

        encoding = utf8_load(encoding_info->version);
        if (IS_ERR(encoding)) {
                ext4_msg(sb, KERN_ERR,
                        "can't mount with superblock charset: %s-%u.%u.%u "
                        "not supported by the kernel. flags: 0x%x.",
                        encoding_info->name,
                        unicode_major(encoding_info->version),
                        unicode_minor(encoding_info->version),
                        unicode_rev(encoding_info->version),
                        encoding_flags);
                return -EINVAL;
        }
        ext4_msg(sb, KERN_INFO,"Using encoding defined by superblock: "
                "%s-%u.%u.%u with flags 0x%hx", encoding_info->name,
                unicode_major(encoding_info->version),
                unicode_minor(encoding_info->version),
                unicode_rev(encoding_info->version),
                encoding_flags);

        sb->s_encoding = encoding;
        sb->s_encoding_flags = encoding_flags;

        return 0;
}
#else
static inline int ext4_encoding_init(struct super_block *sb, struct ext4_super_block *es)
{
        return 0;
}
#endif

static int ext4_init_metadata_csum(struct super_block *sb, struct ext4_super_block *es)
{
        struct ext4_sb_info *sbi = EXT4_SB(sb);

        /* Warn if metadata_csum and gdt_csum are both set. */
        if (ext4_has_feature_metadata_csum(sb) &&
            ext4_has_feature_gdt_csum(sb))
                ext4_warning(sb, "metadata_csum and uninit_bg are "
                             "redundant flags; please run fsck.");

        /* Check for a known checksum algorithm */
        if (!ext4_verify_csum_type(sb, es)) {
                ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
                         "unknown checksum algorithm.");
                return -EINVAL;
        }
        ext4_setup_csum_trigger(sb, EXT4_JTR_ORPHAN_FILE,
                                ext4_orphan_file_block_trigger);

        /* Load the checksum driver */
        sbi->s_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
        if (IS_ERR(sbi->s_chksum_driver)) {
                int ret = PTR_ERR(sbi->s_chksum_driver);
                ext4_msg(sb, KERN_ERR, "Cannot load crc32c driver.");
                sbi->s_chksum_driver = NULL;
                return ret;
        }

        /* Check superblock checksum */
        if (!ext4_superblock_csum_verify(sb, es)) {
                ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
                         "invalid superblock checksum.  Run e2fsck?");
                return -EFSBADCRC;
        }

        /* Precompute checksum seed for all metadata */
        if (ext4_has_feature_csum_seed(sb))
                sbi->s_csum_seed = le32_to_cpu(es->s_checksum_seed);
        else if (ext4_has_metadata_csum(sb) || ext4_has_feature_ea_inode(sb))
                sbi->s_csum_seed = ext4_chksum(sbi, ~0, es->s_uuid,
                                               sizeof(es->s_uuid));
        return 0;
}

static int ext4_check_feature_compatibility(struct super_block *sb,
                                            struct ext4_super_block *es,
                                            int silent)
{
        struct ext4_sb_info *sbi = EXT4_SB(sb);

        if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV &&
            (ext4_has_compat_features(sb) ||
             ext4_has_ro_compat_features(sb) ||
             ext4_has_incompat_features(sb)))
                ext4_msg(sb, KERN_WARNING,
                       "feature flags set on rev 0 fs, "
                       "running e2fsck is recommended");

        if (es->s_creator_os == cpu_to_le32(EXT4_OS_HURD)) {
                set_opt2(sb, HURD_COMPAT);
                if (ext4_has_feature_64bit(sb)) {
                        ext4_msg(sb, KERN_ERR,
                                 "The Hurd can't support 64-bit file systems");
                        return -EINVAL;
                }

                /*
                 * ea_inode feature uses l_i_version field which is not
                 * available in HURD_COMPAT mode.
                 */
                if (ext4_has_feature_ea_inode(sb)) {
                        ext4_msg(sb, KERN_ERR,
                                 "ea_inode feature is not supported for Hurd");
                        return -EINVAL;
                }
        }

        if (IS_EXT2_SB(sb)) {
                if (ext2_feature_set_ok(sb))
                        ext4_msg(sb, KERN_INFO, "mounting ext2 file system "
                                 "using the ext4 subsystem");
                else {
                        /*
                         * If we're probing be silent, if this looks like
                         * it's actually an ext[34] filesystem.
                         */
                        if (silent && ext4_feature_set_ok(sb, sb_rdonly(sb)))
                                return -EINVAL;
                        ext4_msg(sb, KERN_ERR, "couldn't mount as ext2 due "
                                 "to feature incompatibilities");
                        return -EINVAL;
                }
        }

        if (IS_EXT3_SB(sb)) {
                if (ext3_feature_set_ok(sb))
                        ext4_msg(sb, KERN_INFO, "mounting ext3 file system "
                                 "using the ext4 subsystem");
                else {
                        /*
                         * If we're probing be silent, if this looks like
                         * it's actually an ext4 filesystem.
                         */
                        if (silent && ext4_feature_set_ok(sb, sb_rdonly(sb)))
                                return -EINVAL;
                        ext4_msg(sb, KERN_ERR, "couldn't mount as ext3 due "
                                 "to feature incompatibilities");
                        return -EINVAL;
                }
        }

        /*
         * Check feature flags regardless of the revision level, since we
         * previously didn't change the revision level when setting the flags,
         * so there is a chance incompat flags are set on a rev 0 filesystem.
         */
        if (!ext4_feature_set_ok(sb, (sb_rdonly(sb))))
                return -EINVAL;

        if (sbi->s_daxdev) {
                if (sb->s_blocksize == PAGE_SIZE)
                        set_bit(EXT4_FLAGS_BDEV_IS_DAX, &sbi->s_ext4_flags);
                else
                        ext4_msg(sb, KERN_ERR, "unsupported blocksize for DAX\n");
        }

        if (sbi->s_mount_opt & EXT4_MOUNT_DAX_ALWAYS) {
                if (ext4_has_feature_inline_data(sb)) {
                        ext4_msg(sb, KERN_ERR, "Cannot use DAX on a filesystem"
                                        " that may contain inline data");
                        return -EINVAL;
                }
                if (!test_bit(EXT4_FLAGS_BDEV_IS_DAX, &sbi->s_ext4_flags)) {
                        ext4_msg(sb, KERN_ERR,
                                "DAX unsupported by block device.");
                        return -EINVAL;
                }
        }

        if (ext4_has_feature_encrypt(sb) && es->s_encryption_level) {
                ext4_msg(sb, KERN_ERR, "Unsupported encryption level %d",
                         es->s_encryption_level);
                return -EINVAL;
        }

        return 0;
}

static int ext4_check_geometry(struct super_block *sb,
                               struct ext4_super_block *es)
{
        struct ext4_sb_info *sbi = EXT4_SB(sb);
        __u64 blocks_count;
        int err;

        if (le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) > (sb->s_blocksize / 4)) {
                ext4_msg(sb, KERN_ERR,
                         "Number of reserved GDT blocks insanely large: %d",
                         le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks));
                return -EINVAL;
        }
        /*
         * Test whether we have more sectors than will fit in sector_t,
         * and whether the max offset is addressable by the page cache.
         */
        err = generic_check_addressable(sb->s_blocksize_bits,
                                        ext4_blocks_count(es));
        if (err) {
                ext4_msg(sb, KERN_ERR, "filesystem"
                         " too large to mount safely on this system");
                return err;
        }

        /* check blocks count against device size */
        blocks_count = sb_bdev_nr_blocks(sb);
        if (blocks_count && ext4_blocks_count(es) > blocks_count) {
                ext4_msg(sb, KERN_WARNING, "bad geometry: block count %llu "
                       "exceeds size of device (%llu blocks)",
                       ext4_blocks_count(es), blocks_count);
                return -EINVAL;
        }

        /*
         * It makes no sense for the first data block to be beyond the end
         * of the filesystem.
         */
        if (le32_to_cpu(es->s_first_data_block) >= ext4_blocks_count(es)) {
                ext4_msg(sb, KERN_WARNING, "bad geometry: first data "
                         "block %u is beyond end of filesystem (%llu)",
                         le32_to_cpu(es->s_first_data_block),
                         ext4_blocks_count(es));
                return -EINVAL;
        }
        if ((es->s_first_data_block == 0) && (es->s_log_block_size == 0) &&
            (sbi->s_cluster_ratio == 1)) {
                ext4_msg(sb, KERN_WARNING, "bad geometry: first data "
                         "block is 0 with a 1k block and cluster size");
                return -EINVAL;
        }

        blocks_count = (ext4_blocks_count(es) -
                        le32_to_cpu(es->s_first_data_block) +
                        EXT4_BLOCKS_PER_GROUP(sb) - 1);
        do_div(blocks_count, EXT4_BLOCKS_PER_GROUP(sb));
        if (blocks_count > ((uint64_t)1<<32) - EXT4_DESC_PER_BLOCK(sb)) {
                ext4_msg(sb, KERN_WARNING, "groups count too large: %llu "
                       "(block count %llu, first data block %u, "
                       "blocks per group %lu)", blocks_count,
                       ext4_blocks_count(es),
                       le32_to_cpu(es->s_first_data_block),
                       EXT4_BLOCKS_PER_GROUP(sb));
                return -EINVAL;
        }
        sbi->s_groups_count = blocks_count;
        sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
                        (EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
        if (((u64)sbi->s_groups_count * sbi->s_inodes_per_group) !=
            le32_to_cpu(es->s_inodes_count)) {
                ext4_msg(sb, KERN_ERR, "inodes count not valid: %u vs %llu",
                         le32_to_cpu(es->s_inodes_count),
                         ((u64)sbi->s_groups_count * sbi->s_inodes_per_group));
                return -EINVAL;
        }

        return 0;
}

static int ext4_group_desc_init(struct super_block *sb,
                                struct ext4_super_block *es,
                                ext4_fsblk_t logical_sb_block,
                                ext4_group_t *first_not_zeroed)
{
        struct ext4_sb_info *sbi = EXT4_SB(sb);
        unsigned int db_count;
        ext4_fsblk_t block;
        int i;

        db_count = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
                   EXT4_DESC_PER_BLOCK(sb);
        if (ext4_has_feature_meta_bg(sb)) {
                if (le32_to_cpu(es->s_first_meta_bg) > db_count) {
                        ext4_msg(sb, KERN_WARNING,
                                 "first meta block group too large: %u "
                                 "(group descriptor block count %u)",
                                 le32_to_cpu(es->s_first_meta_bg), db_count);
                        return -EINVAL;
                }
        }
        rcu_assign_pointer(sbi->s_group_desc,
                           kvmalloc_array(db_count,
                                          sizeof(struct buffer_head *),
                                          GFP_KERNEL));
        if (sbi->s_group_desc == NULL) {
                ext4_msg(sb, KERN_ERR, "not enough memory");
                return -ENOMEM;
        }

        bgl_lock_init(sbi->s_blockgroup_lock);

        /* Pre-read the descriptors into the buffer cache */
        for (i = 0; i < db_count; i++) {
                block = descriptor_loc(sb, logical_sb_block, i);
                ext4_sb_breadahead_unmovable(sb, block);
        }

        for (i = 0; i < db_count; i++) {
                struct buffer_head *bh;

                block = descriptor_loc(sb, logical_sb_block, i);
                bh = ext4_sb_bread_unmovable(sb, block);
                if (IS_ERR(bh)) {
                        ext4_msg(sb, KERN_ERR,
                               "can't read group descriptor %d", i);
                        sbi->s_gdb_count = i;
                        return PTR_ERR(bh);
                }
                rcu_read_lock();
                rcu_dereference(sbi->s_group_desc)[i] = bh;
                rcu_read_unlock();
        }
        sbi->s_gdb_count = db_count;
        if (!ext4_check_descriptors(sb, logical_sb_block, first_not_zeroed)) {
                ext4_msg(sb, KERN_ERR, "group descriptors corrupted!");
                return -EFSCORRUPTED;
        }

        return 0;
}

static int ext4_load_and_init_journal(struct super_block *sb,
                                      struct ext4_super_block *es,
                                      struct ext4_fs_context *ctx)
{
        struct ext4_sb_info *sbi = EXT4_SB(sb);
        int err;

        err = ext4_load_journal(sb, es, ctx->journal_devnum);
        if (err)
                return err;

        if (ext4_has_feature_64bit(sb) &&
            !jbd2_journal_set_features(EXT4_SB(sb)->s_journal, 0, 0,
                                       JBD2_FEATURE_INCOMPAT_64BIT)) {
                ext4_msg(sb, KERN_ERR, "Failed to set 64-bit journal feature");
                goto out;
        }

        if (!set_journal_csum_feature_set(sb)) {
                ext4_msg(sb, KERN_ERR, "Failed to set journal checksum "
                         "feature set");
                goto out;
        }

        if (test_opt2(sb, JOURNAL_FAST_COMMIT) &&
                !jbd2_journal_set_features(EXT4_SB(sb)->s_journal, 0, 0,
                                          JBD2_FEATURE_INCOMPAT_FAST_COMMIT)) {
                ext4_msg(sb, KERN_ERR,
                        "Failed to set fast commit journal feature");
                goto out;
        }

        /* We have now updated the journal if required, so we can
         * validate the data journaling mode. */
        switch (test_opt(sb, DATA_FLAGS)) {
        case 0:
                /* No mode set, assume a default based on the journal
                 * capabilities: ORDERED_DATA if the journal can
                 * cope, else JOURNAL_DATA
                 */
                if (jbd2_journal_check_available_features
                    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)) {
                        set_opt(sb, ORDERED_DATA);
                        sbi->s_def_mount_opt |= EXT4_MOUNT_ORDERED_DATA;
                } else {
                        set_opt(sb, JOURNAL_DATA);
                        sbi->s_def_mount_opt |= EXT4_MOUNT_JOURNAL_DATA;
                }
                break;

        case EXT4_MOUNT_ORDERED_DATA:
        case EXT4_MOUNT_WRITEBACK_DATA:
                if (!jbd2_journal_check_available_features
                    (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)) {
                        ext4_msg(sb, KERN_ERR, "Journal does not support "
                               "requested data journaling mode");
                        goto out;
                }
                break;
        default:
                break;
        }

        if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA &&
            test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
                ext4_msg(sb, KERN_ERR, "can't mount with "
                        "journal_async_commit in data=ordered mode");
                goto out;
        }

        set_task_ioprio(sbi->s_journal->j_task, ctx->journal_ioprio);

        sbi->s_journal->j_submit_inode_data_buffers =
                ext4_journal_submit_inode_data_buffers;
        sbi->s_journal->j_finish_inode_data_buffers =
                ext4_journal_finish_inode_data_buffers;

        return 0;

out:
        /* flush s_error_work before journal destroy. */
        flush_work(&sbi->s_error_work);
        jbd2_journal_destroy(sbi->s_journal);
        sbi->s_journal = NULL;
        return -EINVAL;
}

static int ext4_check_journal_data_mode(struct super_block *sb)
{
        if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
                printk_once(KERN_WARNING "EXT4-fs: Warning: mounting with "
                            "data=journal disables delayed allocation, "
                            "dioread_nolock, O_DIRECT and fast_commit support!\n");
                /* can't mount with both data=journal and dioread_nolock. */
                clear_opt(sb, DIOREAD_NOLOCK);
                clear_opt2(sb, JOURNAL_FAST_COMMIT);
                if (test_opt2(sb, EXPLICIT_DELALLOC)) {
                        ext4_msg(sb, KERN_ERR, "can't mount with "
                                 "both data=journal and delalloc");
                        return -EINVAL;
                }
                if (test_opt(sb, DAX_ALWAYS)) {
                        ext4_msg(sb, KERN_ERR, "can't mount with "
                                 "both data=journal and dax");
                        return -EINVAL;
                }
                if (ext4_has_feature_encrypt(sb)) {
                        ext4_msg(sb, KERN_WARNING,
                                 "encrypted files will use data=ordered "
                                 "instead of data journaling mode");
                }
                if (test_opt(sb, DELALLOC))
                        clear_opt(sb, DELALLOC);
        } else {
                sb->s_iflags |= SB_I_CGROUPWB;
        }

        return 0;
}

static int ext4_load_super(struct super_block *sb, ext4_fsblk_t *lsb,
                           int silent)
{
        struct ext4_sb_info *sbi = EXT4_SB(sb);
        struct ext4_super_block *es;
        ext4_fsblk_t logical_sb_block;
        unsigned long offset = 0;
        struct buffer_head *bh;
        int ret = -EINVAL;
        int blocksize;

        blocksize = sb_min_blocksize(sb, EXT4_MIN_BLOCK_SIZE);
        if (!blocksize) {
                ext4_msg(sb, KERN_ERR, "unable to set blocksize");
                return -EINVAL;
        }

        /*
         * The ext4 superblock will not be buffer aligned for other than 1kB
         * block sizes.  We need to calculate the offset from buffer start.
         */
        if (blocksize != EXT4_MIN_BLOCK_SIZE) {
                logical_sb_block = sbi->s_sb_block * EXT4_MIN_BLOCK_SIZE;
                offset = do_div(logical_sb_block, blocksize);
        } else {
                logical_sb_block = sbi->s_sb_block;
        }

        bh = ext4_sb_bread_unmovable(sb, logical_sb_block);
        if (IS_ERR(bh)) {
                ext4_msg(sb, KERN_ERR, "unable to read superblock");
                return PTR_ERR(bh);
        }
        /*
         * Note: s_es must be initialized as soon as possible because
         *       some ext4 macro-instructions depend on its value
         */
        es = (struct ext4_super_block *) (bh->b_data + offset);
        sbi->s_es = es;
        sb->s_magic = le16_to_cpu(es->s_magic);
        if (sb->s_magic != EXT4_SUPER_MAGIC) {
                if (!silent)
                        ext4_msg(sb, KERN_ERR, "VFS: Can't find ext4 filesystem");
                goto out;
        }

        if (le32_to_cpu(es->s_log_block_size) >
            (EXT4_MAX_BLOCK_LOG_SIZE - EXT4_MIN_BLOCK_LOG_SIZE)) {
                ext4_msg(sb, KERN_ERR,
                         "Invalid log block size: %u",
                         le32_to_cpu(es->s_log_block_size));
                goto out;
        }
        if (le32_to_cpu(es->s_log_cluster_size) >
            (EXT4_MAX_CLUSTER_LOG_SIZE - EXT4_MIN_BLOCK_LOG_SIZE)) {
                ext4_msg(sb, KERN_ERR,
                         "Invalid log cluster size: %u",
                         le32_to_cpu(es->s_log_cluster_size));
                goto out;
        }

        blocksize = EXT4_MIN_BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);

        /*
         * If the default block size is not the same as the real block size,
         * we need to reload it.
         */
        if (sb->s_blocksize == blocksize) {
                *lsb = logical_sb_block;
                sbi->s_sbh = bh;
                return 0;
        }

        /*
         * bh must be released before kill_bdev(), otherwise
         * it won't be freed and its page also. kill_bdev()
         * is called by sb_set_blocksize().
         */
        brelse(bh);
        /* Validate the filesystem blocksize */
        if (!sb_set_blocksize(sb, blocksize)) {
                ext4_msg(sb, KERN_ERR, "bad block size %d",
                                blocksize);
                bh = NULL;
                goto out;
        }

        logical_sb_block = sbi->s_sb_block * EXT4_MIN_BLOCK_SIZE;
        offset = do_div(logical_sb_block, blocksize);
        bh = ext4_sb_bread_unmovable(sb, logical_sb_block);
        if (IS_ERR(bh)) {
                ext4_msg(sb, KERN_ERR, "Can't read superblock on 2nd try");
                ret = PTR_ERR(bh);
                bh = NULL;
                goto out;
        }
        es = (struct ext4_super_block *)(bh->b_data + offset);
        sbi->s_es = es;
        if (es->s_magic != cpu_to_le16(EXT4_SUPER_MAGIC)) {
                ext4_msg(sb, KERN_ERR, "Magic mismatch, very weird!");
                goto out;
        }
        *lsb = logical_sb_block;
        sbi->s_sbh = bh;
        return 0;
out:
        brelse(bh);
        return ret;
}

static void ext4_hash_info_init(struct super_block *sb)
{
        struct ext4_sb_info *sbi = EXT4_SB(sb);
        struct ext4_super_block *es = sbi->s_es;
        unsigned int i;

        for (i = 0; i < 4; i++)
                sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]);

        sbi->s_def_hash_version = es->s_def_hash_version;
        if (ext4_has_feature_dir_index(sb)) {
                i = le32_to_cpu(es->s_flags);
                if (i & EXT2_FLAGS_UNSIGNED_HASH)
                        sbi->s_hash_unsigned = 3;
                else if ((i & EXT2_FLAGS_SIGNED_HASH) == 0) {
#ifdef __CHAR_UNSIGNED__
                        if (!sb_rdonly(sb))
                                es->s_flags |=
                                        cpu_to_le32(EXT2_FLAGS_UNSIGNED_HASH);
                        sbi->s_hash_unsigned = 3;
#else
                        if (!sb_rdonly(sb))
                                es->s_flags |=
                                        cpu_to_le32(EXT2_FLAGS_SIGNED_HASH);
#endif
                }
        }
}

static int ext4_block_group_meta_init(struct super_block *sb, int silent)
{
        struct ext4_sb_info *sbi = EXT4_SB(sb);
        struct ext4_super_block *es = sbi->s_es;
        int has_huge_files;

        has_huge_files = ext4_has_feature_huge_file(sb);
        sbi->s_bitmap_maxbytes = ext4_max_bitmap_size(sb->s_blocksize_bits,
                                                      has_huge_files);
        sb->s_maxbytes = ext4_max_size(sb->s_blocksize_bits, has_huge_files);

        sbi->s_desc_size = le16_to_cpu(es->s_desc_size);
        if (ext4_has_feature_64bit(sb)) {
                if (sbi->s_desc_size < EXT4_MIN_DESC_SIZE_64BIT ||
                    sbi->s_desc_size > EXT4_MAX_DESC_SIZE ||
                    !is_power_of_2(sbi->s_desc_size)) {
                        ext4_msg(sb, KERN_ERR,
                               "unsupported descriptor size %lu",
                               sbi->s_desc_size);
                        return -EINVAL;
                }
        } else
                sbi->s_desc_size = EXT4_MIN_DESC_SIZE;

        sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
        sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);

        sbi->s_inodes_per_block = sb->s_blocksize / EXT4_INODE_SIZE(sb);
        if (sbi->s_inodes_per_block == 0 || sbi->s_blocks_per_group == 0) {
                if (!silent)
                        ext4_msg(sb, KERN_ERR, "VFS: Can't find ext4 filesystem");
                return -EINVAL;
        }
        if (sbi->s_inodes_per_group < sbi->s_inodes_per_block ||
            sbi->s_inodes_per_group > sb->s_blocksize * 8) {
                ext4_msg(sb, KERN_ERR, "invalid inodes per group: %lu\n",
                         sbi->s_inodes_per_group);
                return -EINVAL;
        }
        sbi->s_itb_per_group = sbi->s_inodes_per_group /
                                        sbi->s_inodes_per_block;
        sbi->s_desc_per_block = sb->s_blocksize / EXT4_DESC_SIZE(sb);
        sbi->s_mount_state = le16_to_cpu(es->s_state) & ~EXT4_FC_REPLAY;
        sbi->s_addr_per_block_bits = ilog2(EXT4_ADDR_PER_BLOCK(sb));
        sbi->s_desc_per_block_bits = ilog2(EXT4_DESC_PER_BLOCK(sb));

        return 0;
}

static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
{
        struct ext4_super_block *es = NULL;
        struct ext4_sb_info *sbi = EXT4_SB(sb);
        ext4_fsblk_t logical_sb_block;
        struct inode *root;
        int needs_recovery;
        int err;
        ext4_group_t first_not_zeroed;
        struct ext4_fs_context *ctx = fc->fs_private;
        int silent = fc->sb_flags & SB_SILENT;

        /* Set defaults for the variables that will be set during parsing */
        if (!(ctx->spec & EXT4_SPEC_JOURNAL_IOPRIO))
                ctx->journal_ioprio = DEFAULT_JOURNAL_IOPRIO;

        sbi->s_inode_readahead_blks = EXT4_DEF_INODE_READAHEAD_BLKS;
        sbi->s_sectors_written_start =
                part_stat_read(sb->s_bdev, sectors[STAT_WRITE]);

        err = ext4_load_super(sb, &logical_sb_block, silent);
        if (err)
                goto out_fail;

        es = sbi->s_es;
        sbi->s_kbytes_written = le64_to_cpu(es->s_kbytes_written);

        err = ext4_init_metadata_csum(sb, es);
        if (err)
                goto failed_mount;

        ext4_set_def_opts(sb, es);

        sbi->s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
        sbi->s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
        sbi->s_commit_interval = JBD2_DEFAULT_MAX_COMMIT_AGE * HZ;
        sbi->s_min_batch_time = EXT4_DEF_MIN_BATCH_TIME;
        sbi->s_max_batch_time = EXT4_DEF_MAX_BATCH_TIME;

        /*
         * set default s_li_wait_mult for lazyinit, for the case there is
         * no mount option specified.
         */
        sbi->s_li_wait_mult = EXT4_DEF_LI_WAIT_MULT;

        err = ext4_inode_info_init(sb, es);
        if (err)
                goto failed_mount;

        err = parse_apply_sb_mount_options(sb, ctx);
        if (err < 0)
                goto failed_mount;

        sbi->s_def_mount_opt = sbi->s_mount_opt;
        sbi->s_def_mount_opt2 = sbi->s_mount_opt2;

        err = ext4_check_opt_consistency(fc, sb);
        if (err < 0)
                goto failed_mount;

        ext4_apply_options(fc, sb);

        err = ext4_encoding_init(sb, es);
        if (err)
                goto failed_mount;

        err = ext4_check_journal_data_mode(sb);
        if (err)
                goto failed_mount;

        sb->s_flags = (sb->s_flags & ~SB_POSIXACL) |
                (test_opt(sb, POSIX_ACL) ? SB_POSIXACL : 0);

        /* i_version is always enabled now */
        sb->s_flags |= SB_I_VERSION;

        err = ext4_check_feature_compatibility(sb, es, silent);
        if (err)
                goto failed_mount;

        err = ext4_block_group_meta_init(sb, silent);
        if (err)
                goto failed_mount;

        ext4_hash_info_init(sb);

        err = ext4_handle_clustersize(sb);
        if (err)
                goto failed_mount;

        err = ext4_check_geometry(sb, es);
        if (err)
                goto failed_mount;

        timer_setup(&sbi->s_err_report, print_daily_error_info, 0);
        spin_lock_init(&sbi->s_error_lock);
        INIT_WORK(&sbi->s_error_work, flush_stashed_error_work);

        err = ext4_group_desc_init(sb, es, logical_sb_block, &first_not_zeroed);
        if (err)
                goto failed_mount3;

        err = ext4_es_register_shrinker(sbi);
        if (err)
                goto failed_mount3;

        sbi->s_stripe = ext4_get_stripe_size(sbi);
        sbi->s_extent_max_zeroout_kb = 32;

        /*
         * set up enough so that it can read an inode
         */
        sb->s_op = &ext4_sops;
        sb->s_export_op = &ext4_export_ops;
        sb->s_xattr = ext4_xattr_handlers;
#ifdef CONFIG_FS_ENCRYPTION
        sb->s_cop = &ext4_cryptops;
#endif
#ifdef CONFIG_FS_VERITY
        sb->s_vop = &ext4_verityops;
#endif
#ifdef CONFIG_QUOTA
        sb->dq_op = &ext4_quota_operations;
        if (ext4_has_feature_quota(sb))
                sb->s_qcop = &dquot_quotactl_sysfile_ops;
        else
                sb->s_qcop = &ext4_qctl_operations;
        sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP | QTYPE_MASK_PRJ;
#endif
        memcpy(&sb->s_uuid, es->s_uuid, sizeof(es->s_uuid));

        INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */
        mutex_init(&sbi->s_orphan_lock);

        ext4_fast_commit_init(sb);

        sb->s_root = NULL;

        needs_recovery = (es->s_last_orphan != 0 ||
                          ext4_has_feature_orphan_present(sb) ||
                          ext4_has_feature_journal_needs_recovery(sb));

        if (ext4_has_feature_mmp(sb) && !sb_rdonly(sb)) {
                err = ext4_multi_mount_protect(sb, le64_to_cpu(es->s_mmp_block));
                if (err)
                        goto failed_mount3a;
        }

        err = -EINVAL;
        /*
         * The first inode we look at is the journal inode.  Don't try
         * root first: it may be modified in the journal!
         */
        if (!test_opt(sb, NOLOAD) && ext4_has_feature_journal(sb)) {
                err = ext4_load_and_init_journal(sb, es, ctx);
                if (err)
                        goto failed_mount3a;
        } else if (test_opt(sb, NOLOAD) && !sb_rdonly(sb) &&
                   ext4_has_feature_journal_needs_recovery(sb)) {
                ext4_msg(sb, KERN_ERR, "required journal recovery "
                       "suppressed and not mounted read-only");
                goto failed_mount3a;
        } else {
                /* Nojournal mode, all journal mount options are illegal */
                if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
                        ext4_msg(sb, KERN_ERR, "can't mount with "
                                 "journal_async_commit, fs mounted w/o journal");
                        goto failed_mount3a;
                }

                if (test_opt2(sb, EXPLICIT_JOURNAL_CHECKSUM)) {
                        ext4_msg(sb, KERN_ERR, "can't mount with "
                                 "journal_checksum, fs mounted w/o journal");
                        goto failed_mount3a;
                }
                if (sbi->s_commit_interval != JBD2_DEFAULT_MAX_COMMIT_AGE*HZ) {
                        ext4_msg(sb, KERN_ERR, "can't mount with "
                                 "commit=%lu, fs mounted w/o journal",
                                 sbi->s_commit_interval / HZ);
                        goto failed_mount3a;
                }
                if (EXT4_MOUNT_DATA_FLAGS &
                    (sbi->s_mount_opt ^ sbi->s_def_mount_opt)) {
                        ext4_msg(sb, KERN_ERR, "can't mount with "
                                 "data=, fs mounted w/o journal");
                        goto failed_mount3a;
                }
                sbi->s_def_mount_opt &= ~EXT4_MOUNT_JOURNAL_CHECKSUM;
                clear_opt(sb, JOURNAL_CHECKSUM);
                clear_opt(sb, DATA_FLAGS);
                clear_opt2(sb, JOURNAL_FAST_COMMIT);
                sbi->s_journal = NULL;
                needs_recovery = 0;
        }

        if (!test_opt(sb, NO_MBCACHE)) {
                sbi->s_ea_block_cache = ext4_xattr_create_cache();
                if (!sbi->s_ea_block_cache) {
                        ext4_msg(sb, KERN_ERR,
                                 "Failed to create ea_block_cache");
                        err = -EINVAL;
                        goto failed_mount_wq;
                }

                if (ext4_has_feature_ea_inode(sb)) {
                        sbi->s_ea_inode_cache = ext4_xattr_create_cache();
                        if (!sbi->s_ea_inode_cache) {
                                ext4_msg(sb, KERN_ERR,
                                         "Failed to create ea_inode_cache");
                                err = -EINVAL;
                                goto failed_mount_wq;
                        }
                }
        }

        /*
         * Get the # of file system overhead blocks from the
         * superblock if present.
         */
        sbi->s_overhead = le32_to_cpu(es->s_overhead_clusters);
        /* ignore the precalculated value if it is ridiculous */
        if (sbi->s_overhead > ext4_blocks_count(es))
                sbi->s_overhead = 0;
        /*
         * If the bigalloc feature is not enabled recalculating the
         * overhead doesn't take long, so we might as well just redo
         * it to make sure we are using the correct value.
         */
        if (!ext4_has_feature_bigalloc(sb))
                sbi->s_overhead = 0;
        if (sbi->s_overhead == 0) {
                err = ext4_calculate_overhead(sb);
                if (err)
                        goto failed_mount_wq;
        }

        /*
         * The maximum number of concurrent works can be high and
         * concurrency isn't really necessary.  Limit it to 1.
         */
        EXT4_SB(sb)->rsv_conversion_wq =
                alloc_workqueue("ext4-rsv-conversion", WQ_MEM_RECLAIM | WQ_UNBOUND, 1);
        if (!EXT4_SB(sb)->rsv_conversion_wq) {
                printk(KERN_ERR "EXT4-fs: failed to create workqueue\n");
                err = -ENOMEM;
                goto failed_mount4;
        }

        /*
         * The jbd2_journal_load will have done any necessary log recovery,
         * so we can safely mount the rest of the filesystem now.
         */

        root = ext4_iget(sb, EXT4_ROOT_INO, EXT4_IGET_SPECIAL);
        if (IS_ERR(root)) {
                ext4_msg(sb, KERN_ERR, "get root inode failed");
                err = PTR_ERR(root);
                root = NULL;
                goto failed_mount4;
        }
        if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
                ext4_msg(sb, KERN_ERR, "corrupt root inode, run e2fsck");
                iput(root);
                err = -EFSCORRUPTED;
                goto failed_mount4;
        }

        sb->s_root = d_make_root(root);
        if (!sb->s_root) {
                ext4_msg(sb, KERN_ERR, "get root dentry failed");
                err = -ENOMEM;
                goto failed_mount4;
        }

        err = ext4_setup_super(sb, es, sb_rdonly(sb));
        if (err == -EROFS) {
                sb->s_flags |= SB_RDONLY;
        } else if (err)
                goto failed_mount4a;

        ext4_set_resv_clusters(sb);

        if (test_opt(sb, BLOCK_VALIDITY)) {
                err = ext4_setup_system_zone(sb);
                if (err) {
                        ext4_msg(sb, KERN_ERR, "failed to initialize system "
                                 "zone (%d)", err);
                        goto failed_mount4a;
                }
        }
        ext4_fc_replay_cleanup(sb);

        ext4_ext_init(sb);

        /*
         * Enable optimize_scan if number of groups is > threshold. This can be
         * turned off by passing "mb_optimize_scan=0". This can also be
         * turned on forcefully by passing "mb_optimize_scan=1".
         */
        if (!(ctx->spec & EXT4_SPEC_mb_optimize_scan)) {
                if (sbi->s_groups_count >= MB_DEFAULT_LINEAR_SCAN_THRESHOLD)
                        set_opt2(sb, MB_OPTIMIZE_SCAN);
                else
                        clear_opt2(sb, MB_OPTIMIZE_SCAN);
        }

        err = ext4_mb_init(sb);
        if (err) {
                ext4_msg(sb, KERN_ERR, "failed to initialize mballoc (%d)",
                         err);
                goto failed_mount5;
        }

        /*
         * We can only set up the journal commit callback once
         * mballoc is initialized
         */
        if (sbi->s_journal)
                sbi->s_journal->j_commit_callback =
                        ext4_journal_commit_callback;

        err = ext4_percpu_param_init(sbi);
        if (err)
                goto failed_mount6;

        if (ext4_has_feature_flex_bg(sb))
                if (!ext4_fill_flex_info(sb)) {
                        ext4_msg(sb, KERN_ERR,
                               "unable to initialize "
                               "flex_bg meta info!");
                        err = -ENOMEM;
                        goto failed_mount6;
                }

        err = ext4_register_li_request(sb, first_not_zeroed);
        if (err)
                goto failed_mount6;

        err = ext4_register_sysfs(sb);
        if (err)
                goto failed_mount7;

        err = ext4_init_orphan_info(sb);
        if (err)
                goto failed_mount8;
#ifdef CONFIG_QUOTA
        /* Enable quota usage during mount. */
        if (ext4_has_feature_quota(sb) && !sb_rdonly(sb)) {
                err = ext4_enable_quotas(sb);
                if (err)
                        goto failed_mount9;
        }
#endif  /* CONFIG_QUOTA */

        /*
         * Save the original bdev mapping's wb_err value which could be
         * used to detect the metadata async write error.
         */
        spin_lock_init(&sbi->s_bdev_wb_lock);
        errseq_check_and_advance(&sb->s_bdev->bd_inode->i_mapping->wb_err,
                                 &sbi->s_bdev_wb_err);
        sb->s_bdev->bd_super = sb;
        EXT4_SB(sb)->s_mount_state |= EXT4_ORPHAN_FS;
        ext4_orphan_cleanup(sb, es);
        EXT4_SB(sb)->s_mount_state &= ~EXT4_ORPHAN_FS;
        /*
         * Update the checksum after updating free space/inode counters and
         * ext4_orphan_cleanup. Otherwise the superblock can have an incorrect
         * checksum in the buffer cache until it is written out and
         * e2fsprogs programs trying to open a file system immediately
         * after it is mounted can fail.
         */
        ext4_superblock_csum_set(sb);
        if (needs_recovery) {
                ext4_msg(sb, KERN_INFO, "recovery complete");
                err = ext4_mark_recovery_complete(sb, es);
                if (err)
                        goto failed_mount9;
        }

        if (test_opt(sb, DISCARD) && !bdev_max_discard_sectors(sb->s_bdev))
                ext4_msg(sb, KERN_WARNING,
                         "mounting with \"discard\" option, but the device does not support discard");

        if (es->s_error_count)
                mod_timer(&sbi->s_err_report, jiffies + 300*HZ); /* 5 minutes */

        /* Enable message ratelimiting. Default is 10 messages per 5 secs. */
        ratelimit_state_init(&sbi->s_err_ratelimit_state, 5 * HZ, 10);
        ratelimit_state_init(&sbi->s_warning_ratelimit_state, 5 * HZ, 10);
        ratelimit_state_init(&sbi->s_msg_ratelimit_state, 5 * HZ, 10);
        atomic_set(&sbi->s_warning_count, 0);
        atomic_set(&sbi->s_msg_count, 0);

        return 0;

failed_mount9:
        ext4_release_orphan_info(sb);
failed_mount8:
        ext4_unregister_sysfs(sb);
        kobject_put(&sbi->s_kobj);
failed_mount7:
        ext4_unregister_li_request(sb);
failed_mount6:
        ext4_mb_release(sb);
        ext4_flex_groups_free(sbi);
        ext4_percpu_param_destroy(sbi);
failed_mount5:
        ext4_ext_release(sb);
        ext4_release_system_zone(sb);
failed_mount4a:
        dput(sb->s_root);
        sb->s_root = NULL;
failed_mount4:
        ext4_msg(sb, KERN_ERR, "mount failed");
        if (EXT4_SB(sb)->rsv_conversion_wq)
                destroy_workqueue(EXT4_SB(sb)->rsv_conversion_wq);
failed_mount_wq:
        ext4_xattr_destroy_cache(sbi->s_ea_inode_cache);
        sbi->s_ea_inode_cache = NULL;

        ext4_xattr_destroy_cache(sbi->s_ea_block_cache);
        sbi->s_ea_block_cache = NULL;

        if (sbi->s_journal) {
                /* flush s_error_work before journal destroy. */
                flush_work(&sbi->s_error_work);
                jbd2_journal_destroy(sbi->s_journal);
                sbi->s_journal = NULL;
        }
failed_mount3a:
        ext4_es_unregister_shrinker(sbi);
failed_mount3:
        /* flush s_error_work before sbi destroy */
        flush_work(&sbi->s_error_work);
        del_timer_sync(&sbi->s_err_report);
        ext4_stop_mmpd(sbi);
        ext4_group_desc_free(sbi);
failed_mount:
        if (sbi->s_chksum_driver)
                crypto_free_shash(sbi->s_chksum_driver);

#if IS_ENABLED(CONFIG_UNICODE)
        utf8_unload(sb->s_encoding);
#endif

#ifdef CONFIG_QUOTA
        for (unsigned int i = 0; i < EXT4_MAXQUOTAS; i++)
                kfree(get_qf_name(sb, sbi, i));
#endif
        fscrypt_free_dummy_policy(&sbi->s_dummy_enc_policy);
        /* ext4_blkdev_remove() calls kill_bdev(), release bh before it. */
        brelse(sbi->s_sbh);
        ext4_blkdev_remove(sbi);
out_fail:
        sb->s_fs_info = NULL;
        return err;
}

static int ext4_fill_super(struct super_block *sb, struct fs_context *fc)
{
        struct ext4_fs_context *ctx = fc->fs_private;
        struct ext4_sb_info *sbi;
        const char *descr;
        int ret;

        sbi = ext4_alloc_sbi(sb);
        if (!sbi)
                return -ENOMEM;

        fc->s_fs_info = sbi;

        /* Cleanup superblock name */
        strreplace(sb->s_id, '/', '!');

        sbi->s_sb_block = 1;    /* Default super block location */
        if (ctx->spec & EXT4_SPEC_s_sb_block)
                sbi->s_sb_block = ctx->s_sb_block;

        ret = __ext4_fill_super(fc, sb);
        if (ret < 0)
                goto free_sbi;

        if (sbi->s_journal) {
                if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
                        descr = " journalled data mode";
                else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
                        descr = " ordered data mode";
                else
                        descr = " writeback data mode";
        } else
                descr = "out journal";

        if (___ratelimit(&ext4_mount_msg_ratelimit, "EXT4-fs mount"))
                ext4_msg(sb, KERN_INFO, "mounted filesystem %pU %s with%s. "
                         "Quota mode: %s.", &sb->s_uuid,
                         sb_rdonly(sb) ? "ro" : "r/w", descr,
                         ext4_quota_mode(sb));

        /* Update the s_overhead_clusters if necessary */
        ext4_update_overhead(sb, false);
        return 0;

free_sbi:
        ext4_free_sbi(sbi);
        fc->s_fs_info = NULL;
        return ret;
}

static int ext4_get_tree(struct fs_context *fc)
{
        return get_tree_bdev(fc, ext4_fill_super);
}

/*
 * Setup any per-fs journal parameters now.  We'll do this both on
 * initial mount, once the journal has been initialised but before we've
 * done any recovery; and again on any subsequent remount.
 */
static void ext4_init_journal_params(struct super_block *sb, journal_t *journal)
{
        struct ext4_sb_info *sbi = EXT4_SB(sb);

        journal->j_commit_interval = sbi->s_commit_interval;
        journal->j_min_batch_time = sbi->s_min_batch_time;
        journal->j_max_batch_time = sbi->s_max_batch_time;
        ext4_fc_init(sb, journal);

        write_lock(&journal->j_state_lock);
        if (test_opt(sb, BARRIER))
                journal->j_flags |= JBD2_BARRIER;
        else
                journal->j_flags &= ~JBD2_BARRIER;
        if (test_opt(sb, DATA_ERR_ABORT))
                journal->j_flags |= JBD2_ABORT_ON_SYNCDATA_ERR;
        else
                journal->j_flags &= ~JBD2_ABORT_ON_SYNCDATA_ERR;
        write_unlock(&journal->j_state_lock);
}

static struct inode *ext4_get_journal_inode(struct super_block *sb,
                                             unsigned int journal_inum)
{
        struct inode *journal_inode;

        /*
         * Test for the existence of a valid inode on disk.  Bad things
         * happen if we iget() an unused inode, as the subsequent iput()
         * will try to delete it.
         */
        journal_inode = ext4_iget(sb, journal_inum, EXT4_IGET_SPECIAL);
        if (IS_ERR(journal_inode)) {
                ext4_msg(sb, KERN_ERR, "no journal found");
                return NULL;
        }
        if (!journal_inode->i_nlink) {
                make_bad_inode(journal_inode);
                iput(journal_inode);
                ext4_msg(sb, KERN_ERR, "journal inode is deleted");
                return NULL;
        }

        ext4_debug("Journal inode found at %p: %lld bytes\n",
                  journal_inode, journal_inode->i_size);
        if (!S_ISREG(journal_inode->i_mode) || IS_ENCRYPTED(journal_inode)) {
                ext4_msg(sb, KERN_ERR, "invalid journal inode");
                iput(journal_inode);
                return NULL;
        }
        return journal_inode;
}

static int ext4_journal_bmap(journal_t *journal, sector_t *block)
{
        struct ext4_map_blocks map;
        int ret;

        if (journal->j_inode == NULL)
                return 0;

        map.m_lblk = *block;
        map.m_len = 1;
        ret = ext4_map_blocks(NULL, journal->j_inode, &map, 0);
        if (ret <= 0) {
                ext4_msg(journal->j_inode->i_sb, KERN_CRIT,
                         "journal bmap failed: block %llu ret %d\n",
                         *block, ret);
                jbd2_journal_abort(journal, ret ? ret : -EIO);
                return ret;
        }
        *block = map.m_pblk;
        return 0;
}

static journal_t *ext4_get_journal(struct super_block *sb,
                                   unsigned int journal_inum)
{
        struct inode *journal_inode;
        journal_t *journal;

        if (WARN_ON_ONCE(!ext4_has_feature_journal(sb)))
                return NULL;

        journal_inode = ext4_get_journal_inode(sb, journal_inum);
        if (!journal_inode)
                return NULL;

        journal = jbd2_journal_init_inode(journal_inode);
        if (!journal) {
                ext4_msg(sb, KERN_ERR, "Could not load journal inode");
                iput(journal_inode);
                return NULL;
        }
        journal->j_private = sb;
        journal->j_bmap = ext4_journal_bmap;
        ext4_init_journal_params(sb, journal);
        return journal;
}

static journal_t *ext4_get_dev_journal(struct super_block *sb,
                                       dev_t j_dev)
{
        struct buffer_head *bh;
        journal_t *journal;
        ext4_fsblk_t start;
        ext4_fsblk_t len;
        int hblock, blocksize;
        ext4_fsblk_t sb_block;
        unsigned long offset;
        struct ext4_super_block *es;
        struct block_device *bdev;

        if (WARN_ON_ONCE(!ext4_has_feature_journal(sb)))
                return NULL;

        bdev = ext4_blkdev_get(j_dev, sb);
        if (bdev == NULL)
                return NULL;

        blocksize = sb->s_blocksize;
        hblock = bdev_logical_block_size(bdev);
        if (blocksize < hblock) {
                ext4_msg(sb, KERN_ERR,
                        "blocksize too small for journal device");
                goto out_bdev;
        }

        sb_block = EXT4_MIN_BLOCK_SIZE / blocksize;
        offset = EXT4_MIN_BLOCK_SIZE % blocksize;
        set_blocksize(bdev, blocksize);
        if (!(bh = __bread(bdev, sb_block, blocksize))) {
                ext4_msg(sb, KERN_ERR, "couldn't read superblock of "
                       "external journal");
                goto out_bdev;
        }

        es = (struct ext4_super_block *) (bh->b_data + offset);
        if ((le16_to_cpu(es->s_magic) != EXT4_SUPER_MAGIC) ||
            !(le32_to_cpu(es->s_feature_incompat) &
              EXT4_FEATURE_INCOMPAT_JOURNAL_DEV)) {
                ext4_msg(sb, KERN_ERR, "external journal has "
                                        "bad superblock");
                brelse(bh);
                goto out_bdev;
        }

        if ((le32_to_cpu(es->s_feature_ro_compat) &
             EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
            es->s_checksum != ext4_superblock_csum(sb, es)) {
                ext4_msg(sb, KERN_ERR, "external journal has "
                                       "corrupt superblock");
                brelse(bh);
                goto out_bdev;
        }

        if (memcmp(EXT4_SB(sb)->s_es->s_journal_uuid, es->s_uuid, 16)) {
                ext4_msg(sb, KERN_ERR, "journal UUID does not match");
                brelse(bh);
                goto out_bdev;
        }

        len = ext4_blocks_count(es);
        start = sb_block + 1;
        brelse(bh);     /* we're done with the superblock */

        journal = jbd2_journal_init_dev(bdev, sb->s_bdev,
                                        start, len, blocksize);
        if (!journal) {
                ext4_msg(sb, KERN_ERR, "failed to create device journal");
                goto out_bdev;
        }
        journal->j_private = sb;
        if (ext4_read_bh_lock(journal->j_sb_buffer, REQ_META | REQ_PRIO, true)) {
                ext4_msg(sb, KERN_ERR, "I/O error on journal device");
                goto out_journal;
        }
        if (be32_to_cpu(journal->j_superblock->s_nr_users) != 1) {
                ext4_msg(sb, KERN_ERR, "External journal has more than one "
                                        "user (unsupported) - %d",
                        be32_to_cpu(journal->j_superblock->s_nr_users));
                goto out_journal;
        }
        EXT4_SB(sb)->s_journal_bdev = bdev;
        ext4_init_journal_params(sb, journal);
        return journal;

out_journal:
        jbd2_journal_destroy(journal);
out_bdev:
        ext4_blkdev_put(bdev);
        return NULL;
}

static int ext4_load_journal(struct super_block *sb,
                             struct ext4_super_block *es,
                             unsigned long journal_devnum)
{
        journal_t *journal;
        unsigned int journal_inum = le32_to_cpu(es->s_journal_inum);
        dev_t journal_dev;
        int err = 0;
        int really_read_only;
        int journal_dev_ro;

        if (WARN_ON_ONCE(!ext4_has_feature_journal(sb)))
                return -EFSCORRUPTED;

        if (journal_devnum &&
            journal_devnum != le32_to_cpu(es->s_journal_dev)) {
                ext4_msg(sb, KERN_INFO, "external journal device major/minor "
                        "numbers have changed");
                journal_dev = new_decode_dev(journal_devnum);
        } else
                journal_dev = new_decode_dev(le32_to_cpu(es->s_journal_dev));

        if (journal_inum && journal_dev) {
                ext4_msg(sb, KERN_ERR,
                         "filesystem has both journal inode and journal device!");
                return -EINVAL;
        }

        if (journal_inum) {
                journal = ext4_get_journal(sb, journal_inum);
                if (!journal)
                        return -EINVAL;
        } else {
                journal = ext4_get_dev_journal(sb, journal_dev);
                if (!journal)
                        return -EINVAL;
        }

        journal_dev_ro = bdev_read_only(journal->j_dev);
        really_read_only = bdev_read_only(sb->s_bdev) | journal_dev_ro;

        if (journal_dev_ro && !sb_rdonly(sb)) {
                ext4_msg(sb, KERN_ERR,
                         "journal device read-only, try mounting with '-o ro'");
                err = -EROFS;
                goto err_out;
        }

        /*
         * Are we loading a blank journal or performing recovery after a
         * crash?  For recovery, we need to check in advance whether we
         * can get read-write access to the device.
         */
        if (ext4_has_feature_journal_needs_recovery(sb)) {
                if (sb_rdonly(sb)) {
                        ext4_msg(sb, KERN_INFO, "INFO: recovery "
                                        "required on readonly filesystem");
                        if (really_read_only) {
                                ext4_msg(sb, KERN_ERR, "write access "
                                        "unavailable, cannot proceed "
                                        "(try mounting with noload)");
                                err = -EROFS;
                                goto err_out;
                        }
                        ext4_msg(sb, KERN_INFO, "write access will "
                               "be enabled during recovery");
                }
        }

        if (!(journal->j_flags & JBD2_BARRIER))
                ext4_msg(sb, KERN_INFO, "barriers disabled");

        if (!ext4_has_feature_journal_needs_recovery(sb))
                err = jbd2_journal_wipe(journal, !really_read_only);
        if (!err) {
                char *save = kmalloc(EXT4_S_ERR_LEN, GFP_KERNEL);

                if (save)
                        memcpy(save, ((char *) es) +
                               EXT4_S_ERR_START, EXT4_S_ERR_LEN);
                err = jbd2_journal_load(journal);
                if (save)
                        memcpy(((char *) es) + EXT4_S_ERR_START,
                               save, EXT4_S_ERR_LEN);
                kfree(save);
                es->s_state |= cpu_to_le16(EXT4_SB(sb)->s_mount_state &
                                           EXT4_ERROR_FS);
                /* Write out restored error information to the superblock */
                if (!bdev_read_only(sb->s_bdev)) {
                        int err2;
                        err2 = ext4_commit_super(sb);
                        err = err ? : err2;
                }
        }

        if (err) {
                ext4_msg(sb, KERN_ERR, "error loading journal");
                goto err_out;
        }

        EXT4_SB(sb)->s_journal = journal;
        err = ext4_clear_journal_err(sb, es);
        if (err) {
                EXT4_SB(sb)->s_journal = NULL;
                jbd2_journal_destroy(journal);
                return err;
        }

        if (!really_read_only && journal_devnum &&
            journal_devnum != le32_to_cpu(es->s_journal_dev)) {
                es->s_journal_dev = cpu_to_le32(journal_devnum);
                ext4_commit_super(sb);
        }
        if (!really_read_only && journal_inum &&
            journal_inum != le32_to_cpu(es->s_journal_inum)) {
                es->s_journal_inum = cpu_to_le32(journal_inum);
                ext4_commit_super(sb);
        }

        return 0;

err_out:
        jbd2_journal_destroy(journal);
        return err;
}

/* Copy state of EXT4_SB(sb) into buffer for on-disk superblock */
static void ext4_update_super(struct super_block *sb)
{
        struct ext4_sb_info *sbi = EXT4_SB(sb);
        struct ext4_super_block *es = sbi->s_es;
        struct buffer_head *sbh = sbi->s_sbh;

        lock_buffer(sbh);
        /*
         * If the file system is mounted read-only, don't update the
         * superblock write time.  This avoids updating the superblock
         * write time when we are mounting the root file system
         * read/only but we need to replay the journal; at that point,
         * for people who are east of GMT and who make their clock
         * tick in localtime for Windows bug-for-bug compatibility,
         * the clock is set in the future, and this will cause e2fsck
         * to complain and force a full file system check.
         */
        if (!(sb->s_flags & SB_RDONLY))
                ext4_update_tstamp(es, s_wtime);
        es->s_kbytes_written =
                cpu_to_le64(sbi->s_kbytes_written +
                    ((part_stat_read(sb->s_bdev, sectors[STAT_WRITE]) -
                      sbi->s_sectors_written_start) >> 1));
        if (percpu_counter_initialized(&sbi->s_freeclusters_counter))
                ext4_free_blocks_count_set(es,
                        EXT4_C2B(sbi, percpu_counter_sum_positive(
                                &sbi->s_freeclusters_counter)));
        if (percpu_counter_initialized(&sbi->s_freeinodes_counter))
                es->s_free_inodes_count =
                        cpu_to_le32(percpu_counter_sum_positive(
                                &sbi->s_freeinodes_counter));
        /* Copy error information to the on-disk superblock */
        spin_lock(&sbi->s_error_lock);
        if (sbi->s_add_error_count > 0) {
                es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
                if (!es->s_first_error_time && !es->s_first_error_time_hi) {
                        __ext4_update_tstamp(&es->s_first_error_time,
                                             &es->s_first_error_time_hi,
                                             sbi->s_first_error_time);
                        strncpy(es->s_first_error_func, sbi->s_first_error_func,
                                sizeof(es->s_first_error_func));
                        es->s_first_error_line =
                                cpu_to_le32(sbi->s_first_error_line);
                        es->s_first_error_ino =
                                cpu_to_le32(sbi->s_first_error_ino);
                        es->s_first_error_block =
                                cpu_to_le64(sbi->s_first_error_block);
                        es->s_first_error_errcode =
                                ext4_errno_to_code(sbi->s_first_error_code);
                }
                __ext4_update_tstamp(&es->s_last_error_time,
                                     &es->s_last_error_time_hi,
                                     sbi->s_last_error_time);
                strncpy(es->s_last_error_func, sbi->s_last_error_func,
                        sizeof(es->s_last_error_func));
                es->s_last_error_line = cpu_to_le32(sbi->s_last_error_line);
                es->s_last_error_ino = cpu_to_le32(sbi->s_last_error_ino);
                es->s_last_error_block = cpu_to_le64(sbi->s_last_error_block);
                es->s_last_error_errcode =
                                ext4_errno_to_code(sbi->s_last_error_code);
                /*
                 * Start the daily error reporting function if it hasn't been
                 * started already
                 */
                if (!es->s_error_count)
                        mod_timer(&sbi->s_err_report, jiffies + 24*60*60*HZ);
                le32_add_cpu(&es->s_error_count, sbi->s_add_error_count);
                sbi->s_add_error_count = 0;
        }
        spin_unlock(&sbi->s_error_lock);

        ext4_superblock_csum_set(sb);
        unlock_buffer(sbh);
}

static int ext4_commit_super(struct super_block *sb)
{
        struct buffer_head *sbh = EXT4_SB(sb)->s_sbh;

        if (!sbh)
                return -EINVAL;
        if (block_device_ejected(sb))
                return -ENODEV;

        ext4_update_super(sb);

        lock_buffer(sbh);
        /* Buffer got discarded which means block device got invalidated */
        if (!buffer_mapped(sbh)) {
                unlock_buffer(sbh);
                return -EIO;
        }

        if (buffer_write_io_error(sbh) || !buffer_uptodate(sbh)) {
                /*
                 * Oh, dear.  A previous attempt to write the
                 * superblock failed.  This could happen because the
                 * USB device was yanked out.  Or it could happen to
                 * be a transient write error and maybe the block will
                 * be remapped.  Nothing we can do but to retry the
                 * write and hope for the best.
                 */
                ext4_msg(sb, KERN_ERR, "previous I/O error to "
                       "superblock detected");
                clear_buffer_write_io_error(sbh);
                set_buffer_uptodate(sbh);
        }
        get_bh(sbh);
        /* Clear potential dirty bit if it was journalled update */
        clear_buffer_dirty(sbh);
        sbh->b_end_io = end_buffer_write_sync;
        submit_bh(REQ_OP_WRITE | REQ_SYNC |
                  (test_opt(sb, BARRIER) ? REQ_FUA : 0), sbh);
        wait_on_buffer(sbh);
        if (buffer_write_io_error(sbh)) {
                ext4_msg(sb, KERN_ERR, "I/O error while writing "
                       "superblock");
                clear_buffer_write_io_error(sbh);
                set_buffer_uptodate(sbh);
                return -EIO;
        }
        return 0;
}

/*
 * Have we just finished recovery?  If so, and if we are mounting (or
 * remounting) the filesystem readonly, then we will end up with a
 * consistent fs on disk.  Record that fact.
 */
static int ext4_mark_recovery_complete(struct super_block *sb,
                                       struct ext4_super_block *es)
{
        int err;
        journal_t *journal = EXT4_SB(sb)->s_journal;

        if (!ext4_has_feature_journal(sb)) {
                if (journal != NULL) {
                        ext4_error(sb, "Journal got removed while the fs was "
                                   "mounted!");
                        return -EFSCORRUPTED;
                }
                return 0;
        }
        jbd2_journal_lock_updates(journal);
        err = jbd2_journal_flush(journal, 0);
        if (err < 0)
                goto out;

        if (sb_rdonly(sb) && (ext4_has_feature_journal_needs_recovery(sb) ||
            ext4_has_feature_orphan_present(sb))) {
                if (!ext4_orphan_file_empty(sb)) {
                        ext4_error(sb, "Orphan file not empty on read-only fs.");
                        err = -EFSCORRUPTED;
                        goto out;
                }
                ext4_clear_feature_journal_needs_recovery(sb);
                ext4_clear_feature_orphan_present(sb);
                ext4_commit_super(sb);
        }
out:
        jbd2_journal_unlock_updates(journal);
        return err;
}

/*
 * If we are mounting (or read-write remounting) a filesystem whose journal
 * has recorded an error from a previous lifetime, move that error to the
 * main filesystem now.
 */
static int ext4_clear_journal_err(struct super_block *sb,
                                   struct ext4_super_block *es)
{
        journal_t *journal;
        int j_errno;
        const char *errstr;

        if (!ext4_has_feature_journal(sb)) {
                ext4_error(sb, "Journal got removed while the fs was mounted!");
                return -EFSCORRUPTED;
        }

        journal = EXT4_SB(sb)->s_journal;

        /*
         * Now check for any error status which may have been recorded in the
         * journal by a prior ext4_error() or ext4_abort()
         */

        j_errno = jbd2_journal_errno(journal);
        if (j_errno) {
                char nbuf[16];

                errstr = ext4_decode_error(sb, j_errno, nbuf);
                ext4_warning(sb, "Filesystem error recorded "
                             "from previous mount: %s", errstr);

                EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
                es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
                j_errno = ext4_commit_super(sb);
                if (j_errno)
                        return j_errno;
                ext4_warning(sb, "Marked fs in need of filesystem check.");

                jbd2_journal_clear_err(journal);
                jbd2_journal_update_sb_errno(journal);
        }
        return 0;
}

/*
 * Force the running and committing transactions to commit,
 * and wait on the commit.
 */
int ext4_force_commit(struct super_block *sb)
{
        journal_t *journal;

        if (sb_rdonly(sb))
                return 0;

        journal = EXT4_SB(sb)->s_journal;
        return ext4_journal_force_commit(journal);
}

static int ext4_sync_fs(struct super_block *sb, int wait)
{
        int ret = 0;
        tid_t target;
        bool needs_barrier = false;
        struct ext4_sb_info *sbi = EXT4_SB(sb);

        if (unlikely(ext4_forced_shutdown(sbi)))
                return 0;

        trace_ext4_sync_fs(sb, wait);
        flush_workqueue(sbi->rsv_conversion_wq);
        /*
         * Writeback quota in non-journalled quota case - journalled quota has
         * no dirty dquots
         */
        dquot_writeback_dquots(sb, -1);
        /*
         * Data writeback is possible w/o journal transaction, so barrier must
         * being sent at the end of the function. But we can skip it if
         * transaction_commit will do it for us.
         */
        if (sbi->s_journal) {
                target = jbd2_get_latest_transaction(sbi->s_journal);
                if (wait && sbi->s_journal->j_flags & JBD2_BARRIER &&
                    !jbd2_trans_will_send_data_barrier(sbi->s_journal, target))
                        needs_barrier = true;

                if (jbd2_journal_start_commit(sbi->s_journal, &target)) {
                        if (wait)
                                ret = jbd2_log_wait_commit(sbi->s_journal,
                                                           target);
                }
        } else if (wait && test_opt(sb, BARRIER))
                needs_barrier = true;
        if (needs_barrier) {
                int err;
                err = blkdev_issue_flush(sb->s_bdev);
                if (!ret)
                        ret = err;
        }

        return ret;
}

/*
 * LVM calls this function before a (read-only) snapshot is created.  This
 * gives us a chance to flush the journal completely and mark the fs clean.
 *
 * Note that only this function cannot bring a filesystem to be in a clean
 * state independently. It relies on upper layer to stop all data & metadata
 * modifications.
 */
static int ext4_freeze(struct super_block *sb)
{
        int error = 0;
        journal_t *journal;

        if (sb_rdonly(sb))
                return 0;

        journal = EXT4_SB(sb)->s_journal;

        if (journal) {
                /* Now we set up the journal barrier. */
                jbd2_journal_lock_updates(journal);

                /*
                 * Don't clear the needs_recovery flag if we failed to
                 * flush the journal.
                 */
                error = jbd2_journal_flush(journal, 0);
                if (error < 0)
                        goto out;

                /* Journal blocked and flushed, clear needs_recovery flag. */
                ext4_clear_feature_journal_needs_recovery(sb);
                if (ext4_orphan_file_empty(sb))
                        ext4_clear_feature_orphan_present(sb);
        }

        error = ext4_commit_super(sb);
out:
        if (journal)
                /* we rely on upper layer to stop further updates */
                jbd2_journal_unlock_updates(journal);
        return error;
}

/*
 * Called by LVM after the snapshot is done.  We need to reset the RECOVER
 * flag here, even though the filesystem is not technically dirty yet.
 */
static int ext4_unfreeze(struct super_block *sb)
{
        if (sb_rdonly(sb) || ext4_forced_shutdown(EXT4_SB(sb)))
                return 0;

        if (EXT4_SB(sb)->s_journal) {
                /* Reset the needs_recovery flag before the fs is unlocked. */
                ext4_set_feature_journal_needs_recovery(sb);
                if (ext4_has_feature_orphan_file(sb))
                        ext4_set_feature_orphan_present(sb);
        }

        ext4_commit_super(sb);
        return 0;
}

/*
 * Structure to save mount options for ext4_remount's benefit
 */
struct ext4_mount_options {
        unsigned long s_mount_opt;
        unsigned long s_mount_opt2;
        kuid_t s_resuid;
        kgid_t s_resgid;
        unsigned long s_commit_interval;
        u32 s_min_batch_time, s_max_batch_time;
#ifdef CONFIG_QUOTA
        int s_jquota_fmt;
        char *s_qf_names[EXT4_MAXQUOTAS];
#endif
};

static int __ext4_remount(struct fs_context *fc, struct super_block *sb)
{
        struct ext4_fs_context *ctx = fc->fs_private;
        struct ext4_super_block *es;
        struct ext4_sb_info *sbi = EXT4_SB(sb);
        unsigned long old_sb_flags;
        struct ext4_mount_options old_opts;
        ext4_group_t g;
        int err = 0;
        int enable_rw = 0;
#ifdef CONFIG_QUOTA
        int enable_quota = 0;
        int i, j;
        char *to_free[EXT4_MAXQUOTAS];
#endif


        /* Store the original options */
        old_sb_flags = sb->s_flags;
        old_opts.s_mount_opt = sbi->s_mount_opt;
        old_opts.s_mount_opt2 = sbi->s_mount_opt2;
        old_opts.s_resuid = sbi->s_resuid;
        old_opts.s_resgid = sbi->s_resgid;
        old_opts.s_commit_interval = sbi->s_commit_interval;
        old_opts.s_min_batch_time = sbi->s_min_batch_time;
        old_opts.s_max_batch_time = sbi->s_max_batch_time;
#ifdef CONFIG_QUOTA
        old_opts.s_jquota_fmt = sbi->s_jquota_fmt;
        for (i = 0; i < EXT4_MAXQUOTAS; i++)
                if (sbi->s_qf_names[i]) {
                        char *qf_name = get_qf_name(sb, sbi, i);

                        old_opts.s_qf_names[i] = kstrdup(qf_name, GFP_KERNEL);
                        if (!old_opts.s_qf_names[i]) {
                                for (j = 0; j < i; j++)
                                        kfree(old_opts.s_qf_names[j]);
                                return -ENOMEM;
                        }
                } else
                        old_opts.s_qf_names[i] = NULL;
#endif
        if (!(ctx->spec & EXT4_SPEC_JOURNAL_IOPRIO)) {
                if (sbi->s_journal && sbi->s_journal->j_task->io_context)
                        ctx->journal_ioprio =
                                sbi->s_journal->j_task->io_context->ioprio;
                else
                        ctx->journal_ioprio = DEFAULT_JOURNAL_IOPRIO;

        }

        ext4_apply_options(fc, sb);

        if ((old_opts.s_mount_opt & EXT4_MOUNT_JOURNAL_CHECKSUM) ^
            test_opt(sb, JOURNAL_CHECKSUM)) {
                ext4_msg(sb, KERN_ERR, "changing journal_checksum "
                         "during remount not supported; ignoring");
                sbi->s_mount_opt ^= EXT4_MOUNT_JOURNAL_CHECKSUM;
        }

        if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
                if (test_opt2(sb, EXPLICIT_DELALLOC)) {
                        ext4_msg(sb, KERN_ERR, "can't mount with "
                                 "both data=journal and delalloc");
                        err = -EINVAL;
                        goto restore_opts;
                }
                if (test_opt(sb, DIOREAD_NOLOCK)) {
                        ext4_msg(sb, KERN_ERR, "can't mount with "
                                 "both data=journal and dioread_nolock");
                        err = -EINVAL;
                        goto restore_opts;
                }
        } else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA) {
                if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
                        ext4_msg(sb, KERN_ERR, "can't mount with "
                                "journal_async_commit in data=ordered mode");
                        err = -EINVAL;
                        goto restore_opts;
                }
        }

        if ((sbi->s_mount_opt ^ old_opts.s_mount_opt) & EXT4_MOUNT_NO_MBCACHE) {
                ext4_msg(sb, KERN_ERR, "can't enable nombcache during remount");
                err = -EINVAL;
                goto restore_opts;
        }

        if (ext4_test_mount_flag(sb, EXT4_MF_FS_ABORTED))
                ext4_abort(sb, ESHUTDOWN, "Abort forced by user");

        sb->s_flags = (sb->s_flags & ~SB_POSIXACL) |
                (test_opt(sb, POSIX_ACL) ? SB_POSIXACL : 0);

        es = sbi->s_es;

        if (sbi->s_journal) {
                ext4_init_journal_params(sb, sbi->s_journal);
                set_task_ioprio(sbi->s_journal->j_task, ctx->journal_ioprio);
        }

        /* Flush outstanding errors before changing fs state */
        flush_work(&sbi->s_error_work);

        if ((bool)(fc->sb_flags & SB_RDONLY) != sb_rdonly(sb)) {
                if (ext4_test_mount_flag(sb, EXT4_MF_FS_ABORTED)) {
                        err = -EROFS;
                        goto restore_opts;
                }

                if (fc->sb_flags & SB_RDONLY) {
                        err = sync_filesystem(sb);
                        if (err < 0)
                                goto restore_opts;
                        err = dquot_suspend(sb, -1);
                        if (err < 0)
                                goto restore_opts;

                        /*
                         * First of all, the unconditional stuff we have to do
                         * to disable replay of the journal when we next remount
                         */
                        sb->s_flags |= SB_RDONLY;

                        /*
                         * OK, test if we are remounting a valid rw partition
                         * readonly, and if so set the rdonly flag and then
                         * mark the partition as valid again.
                         */
                        if (!(es->s_state & cpu_to_le16(EXT4_VALID_FS)) &&
                            (sbi->s_mount_state & EXT4_VALID_FS))
                                es->s_state = cpu_to_le16(sbi->s_mount_state);

                        if (sbi->s_journal) {
                                /*
                                 * We let remount-ro finish even if marking fs
                                 * as clean failed...
                                 */
                                ext4_mark_recovery_complete(sb, es);
                        }
                } else {
                        /* Make sure we can mount this feature set readwrite */
                        if (ext4_has_feature_readonly(sb) ||
                            !ext4_feature_set_ok(sb, 0)) {
                                err = -EROFS;
                                goto restore_opts;
                        }
                        /*
                         * Make sure the group descriptor checksums
                         * are sane.  If they aren't, refuse to remount r/w.
                         */
                        for (g = 0; g < sbi->s_groups_count; g++) {
                                struct ext4_group_desc *gdp =
                                        ext4_get_group_desc(sb, g, NULL);

                                if (!ext4_group_desc_csum_verify(sb, g, gdp)) {
                                        ext4_msg(sb, KERN_ERR,
               "ext4_remount: Checksum for group %u failed (%u!=%u)",
                g, le16_to_cpu(ext4_group_desc_csum(sb, g, gdp)),
                                               le16_to_cpu(gdp->bg_checksum));
                                        err = -EFSBADCRC;
                                        goto restore_opts;
                                }
                        }

                        /*
                         * If we have an unprocessed orphan list hanging
                         * around from a previously readonly bdev mount,
                         * require a full umount/remount for now.
                         */
                        if (es->s_last_orphan || !ext4_orphan_file_empty(sb)) {
                                ext4_msg(sb, KERN_WARNING, "Couldn't "
                                       "remount RDWR because of unprocessed "
                                       "orphan inode list.  Please "
                                       "umount/remount instead");
                                err = -EINVAL;
                                goto restore_opts;
                        }

                        /*
                         * Mounting a RDONLY partition read-write, so reread
                         * and store the current valid flag.  (It may have
                         * been changed by e2fsck since we originally mounted
                         * the partition.)
                         */
                        if (sbi->s_journal) {
                                err = ext4_clear_journal_err(sb, es);
                                if (err)
                                        goto restore_opts;
                        }
                        sbi->s_mount_state = (le16_to_cpu(es->s_state) &
                                              ~EXT4_FC_REPLAY);

                        err = ext4_setup_super(sb, es, 0);
                        if (err)
                                goto restore_opts;

                        enable_rw = 1;
                        if (ext4_has_feature_mmp(sb)) {
                                err = ext4_multi_mount_protect(sb,
                                                le64_to_cpu(es->s_mmp_block));
                                if (err)
                                        goto restore_opts;
                        }
#ifdef CONFIG_QUOTA
                        enable_quota = 1;
#endif
                }
        }

        /*
         * Reinitialize lazy itable initialization thread based on
         * current settings
         */
        if (sb_rdonly(sb) || !test_opt(sb, INIT_INODE_TABLE))
                ext4_unregister_li_request(sb);
        else {
                ext4_group_t first_not_zeroed;
                first_not_zeroed = ext4_has_uninit_itable(sb);
                ext4_register_li_request(sb, first_not_zeroed);
        }

        /*
         * Handle creation of system zone data early because it can fail.
         * Releasing of existing data is done when we are sure remount will
         * succeed.
         */
        if (test_opt(sb, BLOCK_VALIDITY) && !sbi->s_system_blks) {
                err = ext4_setup_system_zone(sb);
                if (err)
                        goto restore_opts;
        }

        if (sbi->s_journal == NULL && !(old_sb_flags & SB_RDONLY)) {
                err = ext4_commit_super(sb);
                if (err)
                        goto restore_opts;
        }

#ifdef CONFIG_QUOTA
        if (enable_quota) {
                if (sb_any_quota_suspended(sb))
                        dquot_resume(sb, -1);
                else if (ext4_has_feature_quota(sb)) {
                        err = ext4_enable_quotas(sb);
                        if (err)
                                goto restore_opts;
                }
        }
        /* Release old quota file names */
        for (i = 0; i < EXT4_MAXQUOTAS; i++)
                kfree(old_opts.s_qf_names[i]);
#endif
        if (!test_opt(sb, BLOCK_VALIDITY) && sbi->s_system_blks)
                ext4_release_system_zone(sb);

        if (enable_rw)
                sb->s_flags &= ~SB_RDONLY;

        if (!ext4_has_feature_mmp(sb) || sb_rdonly(sb))
                ext4_stop_mmpd(sbi);

        return 0;

restore_opts:
        /*
         * If there was a failing r/w to ro transition, we may need to
         * re-enable quota
         */
        if ((sb->s_flags & SB_RDONLY) && !(old_sb_flags & SB_RDONLY) &&
            sb_any_quota_suspended(sb))
                dquot_resume(sb, -1);
        sb->s_flags = old_sb_flags;
        sbi->s_mount_opt = old_opts.s_mount_opt;
        sbi->s_mount_opt2 = old_opts.s_mount_opt2;
        sbi->s_resuid = old_opts.s_resuid;
        sbi->s_resgid = old_opts.s_resgid;
        sbi->s_commit_interval = old_opts.s_commit_interval;
        sbi->s_min_batch_time = old_opts.s_min_batch_time;
        sbi->s_max_batch_time = old_opts.s_max_batch_time;
        if (!test_opt(sb, BLOCK_VALIDITY) && sbi->s_system_blks)
                ext4_release_system_zone(sb);
#ifdef CONFIG_QUOTA
        sbi->s_jquota_fmt = old_opts.s_jquota_fmt;
        for (i = 0; i < EXT4_MAXQUOTAS; i++) {
                to_free[i] = get_qf_name(sb, sbi, i);
                rcu_assign_pointer(sbi->s_qf_names[i], old_opts.s_qf_names[i]);
        }
        synchronize_rcu();
        for (i = 0; i < EXT4_MAXQUOTAS; i++)
                kfree(to_free[i]);
#endif
        if (!ext4_has_feature_mmp(sb) || sb_rdonly(sb))
                ext4_stop_mmpd(sbi);
        return err;
}

static int ext4_reconfigure(struct fs_context *fc)
{
        struct super_block *sb = fc->root->d_sb;
        int ret;

        fc->s_fs_info = EXT4_SB(sb);

        ret = ext4_check_opt_consistency(fc, sb);
        if (ret < 0)
                return ret;

        ret = __ext4_remount(fc, sb);
        if (ret < 0)
                return ret;

        ext4_msg(sb, KERN_INFO, "re-mounted %pU %s. Quota mode: %s.",
                 &sb->s_uuid, sb_rdonly(sb) ? "ro" : "r/w",
                 ext4_quota_mode(sb));

        return 0;
}

#ifdef CONFIG_QUOTA
static int ext4_statfs_project(struct super_block *sb,
                               kprojid_t projid, struct kstatfs *buf)
{
        struct kqid qid;
        struct dquot *dquot;
        u64 limit;
        u64 curblock;

        qid = make_kqid_projid(projid);
        dquot = dqget(sb, qid);
        if (IS_ERR(dquot))
                return PTR_ERR(dquot);
        spin_lock(&dquot->dq_dqb_lock);

        limit = min_not_zero(dquot->dq_dqb.dqb_bsoftlimit,
                             dquot->dq_dqb.dqb_bhardlimit);
        limit >>= sb->s_blocksize_bits;

        if (limit && buf->f_blocks > limit) {
                curblock = (dquot->dq_dqb.dqb_curspace +
                            dquot->dq_dqb.dqb_rsvspace) >> sb->s_blocksize_bits;
                buf->f_blocks = limit;
                buf->f_bfree = buf->f_bavail =
                        (buf->f_blocks > curblock) ?
                         (buf->f_blocks - curblock) : 0;
        }

        limit = min_not_zero(dquot->dq_dqb.dqb_isoftlimit,
                             dquot->dq_dqb.dqb_ihardlimit);
        if (limit && buf->f_files > limit) {
                buf->f_files = limit;
                buf->f_ffree =
                        (buf->f_files > dquot->dq_dqb.dqb_curinodes) ?
                         (buf->f_files - dquot->dq_dqb.dqb_curinodes) : 0;
        }

        spin_unlock(&dquot->dq_dqb_lock);
        dqput(dquot);
        return 0;
}
#endif

static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf)
{
        struct super_block *sb = dentry->d_sb;
        struct ext4_sb_info *sbi = EXT4_SB(sb);
        struct ext4_super_block *es = sbi->s_es;
        ext4_fsblk_t overhead = 0, resv_blocks;
        s64 bfree;
        resv_blocks = EXT4_C2B(sbi, atomic64_read(&sbi->s_resv_clusters));

        if (!test_opt(sb, MINIX_DF))
                overhead = sbi->s_overhead;

        buf->f_type = EXT4_SUPER_MAGIC;
        buf->f_bsize = sb->s_blocksize;
        buf->f_blocks = ext4_blocks_count(es) - EXT4_C2B(sbi, overhead);
        bfree = percpu_counter_sum_positive(&sbi->s_freeclusters_counter) -
                percpu_counter_sum_positive(&sbi->s_dirtyclusters_counter);
        /* prevent underflow in case that few free space is available */
        buf->f_bfree = EXT4_C2B(sbi, max_t(s64, bfree, 0));
        buf->f_bavail = buf->f_bfree -
                        (ext4_r_blocks_count(es) + resv_blocks);
        if (buf->f_bfree < (ext4_r_blocks_count(es) + resv_blocks))
                buf->f_bavail = 0;
        buf->f_files = le32_to_cpu(es->s_inodes_count);
        buf->f_ffree = percpu_counter_sum_positive(&sbi->s_freeinodes_counter);
        buf->f_namelen = EXT4_NAME_LEN;
        buf->f_fsid = uuid_to_fsid(es->s_uuid);

#ifdef CONFIG_QUOTA
        if (ext4_test_inode_flag(dentry->d_inode, EXT4_INODE_PROJINHERIT) &&
            sb_has_quota_limits_enabled(sb, PRJQUOTA))
                ext4_statfs_project(sb, EXT4_I(dentry->d_inode)->i_projid, buf);
#endif
        return 0;
}


#ifdef CONFIG_QUOTA

/*
 * Helper functions so that transaction is started before we acquire dqio_sem
 * to keep correct lock ordering of transaction > dqio_sem
 */
static inline struct inode *dquot_to_inode(struct dquot *dquot)
{
        return sb_dqopt(dquot->dq_sb)->files[dquot->dq_id.type];
}

static int ext4_write_dquot(struct dquot *dquot)
{
        int ret, err;
        handle_t *handle;
        struct inode *inode;

        inode = dquot_to_inode(dquot);
        handle = ext4_journal_start(inode, EXT4_HT_QUOTA,
                                    EXT4_QUOTA_TRANS_BLOCKS(dquot->dq_sb));
        if (IS_ERR(handle))
                return PTR_ERR(handle);
        ret = dquot_commit(dquot);
        err = ext4_journal_stop(handle);
        if (!ret)
                ret = err;
        return ret;
}

static int ext4_acquire_dquot(struct dquot *dquot)
{
        int ret, err;
        handle_t *handle;

        handle = ext4_journal_start(dquot_to_inode(dquot), EXT4_HT_QUOTA,
                                    EXT4_QUOTA_INIT_BLOCKS(dquot->dq_sb));
        if (IS_ERR(handle))
                return PTR_ERR(handle);
        ret = dquot_acquire(dquot);
        err = ext4_journal_stop(handle);
        if (!ret)
                ret = err;
        return ret;
}

static int ext4_release_dquot(struct dquot *dquot)
{
        int ret, err;
        handle_t *handle;

        handle = ext4_journal_start(dquot_to_inode(dquot), EXT4_HT_QUOTA,
                                    EXT4_QUOTA_DEL_BLOCKS(dquot->dq_sb));
        if (IS_ERR(handle)) {
                /* Release dquot anyway to avoid endless cycle in dqput() */
                dquot_release(dquot);
                return PTR_ERR(handle);
        }
        ret = dquot_release(dquot);
        err = ext4_journal_stop(handle);
        if (!ret)
                ret = err;
        return ret;
}

static int ext4_mark_dquot_dirty(struct dquot *dquot)
{
        struct super_block *sb = dquot->dq_sb;

        if (ext4_is_quota_journalled(sb)) {
                dquot_mark_dquot_dirty(dquot);
                return ext4_write_dquot(dquot);
        } else {
                return dquot_mark_dquot_dirty(dquot);
        }
}

static int ext4_write_info(struct super_block *sb, int type)
{
        int ret, err;
        handle_t *handle;

        /* Data block + inode block */
        handle = ext4_journal_start_sb(sb, EXT4_HT_QUOTA, 2);
        if (IS_ERR(handle))
                return PTR_ERR(handle);
        ret = dquot_commit_info(sb, type);
        err = ext4_journal_stop(handle);
        if (!ret)
                ret = err;
        return ret;
}

static void lockdep_set_quota_inode(struct inode *inode, int subclass)
{
        struct ext4_inode_info *ei = EXT4_I(inode);

        /* The first argument of lockdep_set_subclass has to be
         * *exactly* the same as the argument to init_rwsem() --- in
         * this case, in init_once() --- or lockdep gets unhappy
         * because the name of the lock is set using the
         * stringification of the argument to init_rwsem().
         */
        (void) ei;      /* shut up clang warning if !CONFIG_LOCKDEP */
        lockdep_set_subclass(&ei->i_data_sem, subclass);
}

/*
 * Standard function to be called on quota_on
 */
static int ext4_quota_on(struct super_block *sb, int type, int format_id,
                         const struct path *path)
{
        int err;

        if (!test_opt(sb, QUOTA))
                return -EINVAL;

        /* Quotafile not on the same filesystem? */
        if (path->dentry->d_sb != sb)
                return -EXDEV;

        /* Quota already enabled for this file? */
        if (IS_NOQUOTA(d_inode(path->dentry)))
                return -EBUSY;

        /* Journaling quota? */
        if (EXT4_SB(sb)->s_qf_names[type]) {
                /* Quotafile not in fs root? */
                if (path->dentry->d_parent != sb->s_root)
                        ext4_msg(sb, KERN_WARNING,
                                "Quota file not on filesystem root. "
                                "Journaled quota will not work");
                sb_dqopt(sb)->flags |= DQUOT_NOLIST_DIRTY;
        } else {
                /*
                 * Clear the flag just in case mount options changed since
                 * last time.
                 */
                sb_dqopt(sb)->flags &= ~DQUOT_NOLIST_DIRTY;
        }

        lockdep_set_quota_inode(path->dentry->d_inode, I_DATA_SEM_QUOTA);
        err = dquot_quota_on(sb, type, format_id, path);
        if (!err) {
                struct inode *inode = d_inode(path->dentry);
                handle_t *handle;

                /*
                 * Set inode flags to prevent userspace from messing with quota
                 * files. If this fails, we return success anyway since quotas
                 * are already enabled and this is not a hard failure.
                 */
                inode_lock(inode);
                handle = ext4_journal_start(inode, EXT4_HT_QUOTA, 1);
                if (IS_ERR(handle))
                        goto unlock_inode;
                EXT4_I(inode)->i_flags |= EXT4_NOATIME_FL | EXT4_IMMUTABLE_FL;
                inode_set_flags(inode, S_NOATIME | S_IMMUTABLE,
                                S_NOATIME | S_IMMUTABLE);
                err = ext4_mark_inode_dirty(handle, inode);
                ext4_journal_stop(handle);
        unlock_inode:
                inode_unlock(inode);
                if (err)
                        dquot_quota_off(sb, type);
        }
        if (err)
                lockdep_set_quota_inode(path->dentry->d_inode,
                                             I_DATA_SEM_NORMAL);
        return err;
}

static inline bool ext4_check_quota_inum(int type, unsigned long qf_inum)
{
        switch (type) {
        case USRQUOTA:
                return qf_inum == EXT4_USR_QUOTA_INO;
        case GRPQUOTA:
                return qf_inum == EXT4_GRP_QUOTA_INO;
        case PRJQUOTA:
                return qf_inum >= EXT4_GOOD_OLD_FIRST_INO;
        default:
                BUG();
        }
}

static int ext4_quota_enable(struct super_block *sb, int type, int format_id,
                             unsigned int flags)
{
        int err;
        struct inode *qf_inode;
        unsigned long qf_inums[EXT4_MAXQUOTAS] = {
                le32_to_cpu(EXT4_SB(sb)->s_es->s_usr_quota_inum),
                le32_to_cpu(EXT4_SB(sb)->s_es->s_grp_quota_inum),
                le32_to_cpu(EXT4_SB(sb)->s_es->s_prj_quota_inum)
        };

        BUG_ON(!ext4_has_feature_quota(sb));

        if (!qf_inums[type])
                return -EPERM;

        if (!ext4_check_quota_inum(type, qf_inums[type])) {
                ext4_error(sb, "Bad quota inum: %lu, type: %d",
                                qf_inums[type], type);
                return -EUCLEAN;
        }

        qf_inode = ext4_iget(sb, qf_inums[type], EXT4_IGET_SPECIAL);
        if (IS_ERR(qf_inode)) {
                ext4_error(sb, "Bad quota inode: %lu, type: %d",
                                qf_inums[type], type);
                return PTR_ERR(qf_inode);
        }

        /* Don't account quota for quota files to avoid recursion */
        qf_inode->i_flags |= S_NOQUOTA;
        lockdep_set_quota_inode(qf_inode, I_DATA_SEM_QUOTA);
        err = dquot_load_quota_inode(qf_inode, type, format_id, flags);
        if (err)
                lockdep_set_quota_inode(qf_inode, I_DATA_SEM_NORMAL);
        iput(qf_inode);

        return err;
}

/* Enable usage tracking for all quota types. */
int ext4_enable_quotas(struct super_block *sb)
{
        int type, err = 0;
        unsigned long qf_inums[EXT4_MAXQUOTAS] = {
                le32_to_cpu(EXT4_SB(sb)->s_es->s_usr_quota_inum),
                le32_to_cpu(EXT4_SB(sb)->s_es->s_grp_quota_inum),
                le32_to_cpu(EXT4_SB(sb)->s_es->s_prj_quota_inum)
        };
        bool quota_mopt[EXT4_MAXQUOTAS] = {
                test_opt(sb, USRQUOTA),
                test_opt(sb, GRPQUOTA),
                test_opt(sb, PRJQUOTA),
        };

        sb_dqopt(sb)->flags |= DQUOT_QUOTA_SYS_FILE | DQUOT_NOLIST_DIRTY;
        for (type = 0; type < EXT4_MAXQUOTAS; type++) {
                if (qf_inums[type]) {
                        err = ext4_quota_enable(sb, type, QFMT_VFS_V1,
                                DQUOT_USAGE_ENABLED |
                                (quota_mopt[type] ? DQUOT_LIMITS_ENABLED : 0));
                        if (err) {
                                ext4_warning(sb,
                                        "Failed to enable quota tracking "
                                        "(type=%d, err=%d, ino=%lu). "
                                        "Please run e2fsck to fix.", type,
                                        err, qf_inums[type]);
                                for (type--; type >= 0; type--) {
                                        struct inode *inode;

                                        inode = sb_dqopt(sb)->files[type];
                                        if (inode)
                                                inode = igrab(inode);
                                        dquot_quota_off(sb, type);
                                        if (inode) {
                                                lockdep_set_quota_inode(inode,
                                                        I_DATA_SEM_NORMAL);
                                                iput(inode);
                                        }
                                }

                                return err;
                        }
                }
        }
        return 0;
}

static int ext4_quota_off(struct super_block *sb, int type)
{
        struct inode *inode = sb_dqopt(sb)->files[type];
        handle_t *handle;
        int err;

        /* Force all delayed allocation blocks to be allocated.
         * Caller already holds s_umount sem */
        if (test_opt(sb, DELALLOC))
                sync_filesystem(sb);

        if (!inode || !igrab(inode))
                goto out;

        err = dquot_quota_off(sb, type);
        if (err || ext4_has_feature_quota(sb))
                goto out_put;

        inode_lock(inode);
        /*
         * Update modification times of quota files when userspace can
         * start looking at them. If we fail, we return success anyway since
         * this is not a hard failure and quotas are already disabled.
         */
        handle = ext4_journal_start(inode, EXT4_HT_QUOTA, 1);
        if (IS_ERR(handle)) {
                err = PTR_ERR(handle);
                goto out_unlock;
        }
        EXT4_I(inode)->i_flags &= ~(EXT4_NOATIME_FL | EXT4_IMMUTABLE_FL);
        inode_set_flags(inode, 0, S_NOATIME | S_IMMUTABLE);
        inode->i_mtime = inode->i_ctime = current_time(inode);
        err = ext4_mark_inode_dirty(handle, inode);
        ext4_journal_stop(handle);
out_unlock:
        inode_unlock(inode);
out_put:
        lockdep_set_quota_inode(inode, I_DATA_SEM_NORMAL);
        iput(inode);
        return err;
out:
        return dquot_quota_off(sb, type);
}

/* Read data from quotafile - avoid pagecache and such because we cannot afford
 * acquiring the locks... As quota files are never truncated and quota code
 * itself serializes the operations (and no one else should touch the files)
 * we don't have to be afraid of races */
static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
                               size_t len, loff_t off)
{
        struct inode *inode = sb_dqopt(sb)->files[type];
        ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
        int offset = off & (sb->s_blocksize - 1);
        int tocopy;
        size_t toread;
        struct buffer_head *bh;
        loff_t i_size = i_size_read(inode);

        if (off > i_size)
                return 0;
        if (off+len > i_size)
                len = i_size-off;
        toread = len;
        while (toread > 0) {
                tocopy = min_t(unsigned long, sb->s_blocksize - offset, toread);
                bh = ext4_bread(NULL, inode, blk, 0);
                if (IS_ERR(bh))
                        return PTR_ERR(bh);
                if (!bh)        /* A hole? */
                        memset(data, 0, tocopy);
                else
                        memcpy(data, bh->b_data+offset, tocopy);
                brelse(bh);
                offset = 0;
                toread -= tocopy;
                data += tocopy;
                blk++;
        }
        return len;
}

/* Write to quotafile (we know the transaction is already started and has
 * enough credits) */
static ssize_t ext4_quota_write(struct super_block *sb, int type,
                                const char *data, size_t len, loff_t off)
{
        struct inode *inode = sb_dqopt(sb)->files[type];
        ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
        int err = 0, err2 = 0, offset = off & (sb->s_blocksize - 1);
        int retries = 0;
        struct buffer_head *bh;
        handle_t *handle = journal_current_handle();

        if (!handle) {
                ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
                        " cancelled because transaction is not started",
                        (unsigned long long)off, (unsigned long long)len);
                return -EIO;
        }
        /*
         * Since we account only one data block in transaction credits,
         * then it is impossible to cross a block boundary.
         */
        if (sb->s_blocksize - offset < len) {
                ext4_msg(sb, KERN_WARNING, "Quota write (off=%llu, len=%llu)"
                        " cancelled because not block aligned",
                        (unsigned long long)off, (unsigned long long)len);
                return -EIO;
        }

        do {
                bh = ext4_bread(handle, inode, blk,
                                EXT4_GET_BLOCKS_CREATE |
                                EXT4_GET_BLOCKS_METADATA_NOFAIL);
        } while (PTR_ERR(bh) == -ENOSPC &&
                 ext4_should_retry_alloc(inode->i_sb, &retries));
        if (IS_ERR(bh))
                return PTR_ERR(bh);
        if (!bh)
                goto out;
        BUFFER_TRACE(bh, "get write access");
        err = ext4_journal_get_write_access(handle, sb, bh, EXT4_JTR_NONE);
        if (err) {
                brelse(bh);
                return err;
        }
        lock_buffer(bh);
        memcpy(bh->b_data+offset, data, len);
        flush_dcache_page(bh->b_page);
        unlock_buffer(bh);
        err = ext4_handle_dirty_metadata(handle, NULL, bh);
        brelse(bh);
out:
        if (inode->i_size < off + len) {
                i_size_write(inode, off + len);
                EXT4_I(inode)->i_disksize = inode->i_size;
                err2 = ext4_mark_inode_dirty(handle, inode);
                if (unlikely(err2 && !err))
                        err = err2;
        }
        return err ? err : len;
}
#endif

#if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT2)
static inline void register_as_ext2(void)
{
        int err = register_filesystem(&ext2_fs_type);
        if (err)
                printk(KERN_WARNING
                       "EXT4-fs: Unable to register as ext2 (%d)\n", err);
}

static inline void unregister_as_ext2(void)
{
        unregister_filesystem(&ext2_fs_type);
}

static inline int ext2_feature_set_ok(struct super_block *sb)
{
        if (ext4_has_unknown_ext2_incompat_features(sb))
                return 0;
        if (sb_rdonly(sb))
                return 1;
        if (ext4_has_unknown_ext2_ro_compat_features(sb))
                return 0;
        return 1;
}
#else
static inline void register_as_ext2(void) { }
static inline void unregister_as_ext2(void) { }
static inline int ext2_feature_set_ok(struct super_block *sb) { return 0; }
#endif

static inline void register_as_ext3(void)
{
        int err = register_filesystem(&ext3_fs_type);
        if (err)
                printk(KERN_WARNING
                       "EXT4-fs: Unable to register as ext3 (%d)\n", err);
}

static inline void unregister_as_ext3(void)
{
        unregister_filesystem(&ext3_fs_type);
}

static inline int ext3_feature_set_ok(struct super_block *sb)
{
        if (ext4_has_unknown_ext3_incompat_features(sb))
                return 0;
        if (!ext4_has_feature_journal(sb))
                return 0;
        if (sb_rdonly(sb))
                return 1;
        if (ext4_has_unknown_ext3_ro_compat_features(sb))
                return 0;
        return 1;
}

static struct file_system_type ext4_fs_type = {
        .owner                  = THIS_MODULE,
        .name                   = "ext4",
        .init_fs_context        = ext4_init_fs_context,
        .parameters             = ext4_param_specs,
        .kill_sb                = kill_block_super,
        .fs_flags               = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
};
MODULE_ALIAS_FS("ext4");

/* Shared across all ext4 file systems */
wait_queue_head_t ext4__ioend_wq[EXT4_WQ_HASH_SZ];

static int __init ext4_init_fs(void)
{
        int i, err;

        ratelimit_state_init(&ext4_mount_msg_ratelimit, 30 * HZ, 64);
        ext4_li_info = NULL;

        /* Build-time check for flags consistency */
        ext4_check_flag_values();

        for (i = 0; i < EXT4_WQ_HASH_SZ; i++)
                init_waitqueue_head(&ext4__ioend_wq[i]);

        err = ext4_init_es();
        if (err)
                return err;

        err = ext4_init_pending();
        if (err)
                goto out7;

        err = ext4_init_post_read_processing();
        if (err)
                goto out6;

        err = ext4_init_pageio();
        if (err)
                goto out5;

        err = ext4_init_system_zone();
        if (err)
                goto out4;

        err = ext4_init_sysfs();
        if (err)
                goto out3;

        err = ext4_init_mballoc();
        if (err)
                goto out2;
        err = init_inodecache();
        if (err)
                goto out1;

        err = ext4_fc_init_dentry_cache();
        if (err)
                goto out05;

        register_as_ext3();
        register_as_ext2();
        err = register_filesystem(&ext4_fs_type);
        if (err)
                goto out;

        return 0;
out:
        unregister_as_ext2();
        unregister_as_ext3();
        ext4_fc_destroy_dentry_cache();
out05:
        destroy_inodecache();
out1:
        ext4_exit_mballoc();
out2:
        ext4_exit_sysfs();
out3:
        ext4_exit_system_zone();
out4:
        ext4_exit_pageio();
out5:
        ext4_exit_post_read_processing();
out6:
        ext4_exit_pending();
out7:
        ext4_exit_es();

        return err;
}

static void __exit ext4_exit_fs(void)
{
        ext4_destroy_lazyinit_thread();
        unregister_as_ext2();
        unregister_as_ext3();
        unregister_filesystem(&ext4_fs_type);
        ext4_fc_destroy_dentry_cache();
        destroy_inodecache();
        ext4_exit_mballoc();
        ext4_exit_sysfs();
        ext4_exit_system_zone();
        ext4_exit_pageio();
        ext4_exit_post_read_processing();
        ext4_exit_es();
        ext4_exit_pending();
}

MODULE_AUTHOR("Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others");
MODULE_DESCRIPTION("Fourth Extended Filesystem");
MODULE_LICENSE("GPL");
MODULE_SOFTDEP("pre: crc32c");
module_init(ext4_init_fs)
module_exit(ext4_exit_fs)