[mirror_ubuntu-bionic-kernel.git] / fs / f2fs / super.c

/*
 * fs/f2fs/super.c
 *
 * Copyright (c) 2012 Samsung Electronics Co., Ltd.
 *             http://www.samsung.com/
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/statfs.h>
#include <linux/buffer_head.h>
#include <linux/backing-dev.h>
#include <linux/kthread.h>
#include <linux/parser.h>
#include <linux/mount.h>
#include <linux/seq_file.h>
#include <linux/proc_fs.h>
#include <linux/random.h>
#include <linux/exportfs.h>
#include <linux/blkdev.h>
#include <linux/f2fs_fs.h>
#include <linux/sysfs.h>

#include "f2fs.h"
#include "node.h"
#include "segment.h"
#include "xattr.h"
#include "gc.h"
#include "trace.h"

#define CREATE_TRACE_POINTS
#include <trace/events/f2fs.h>

static struct proc_dir_entry *f2fs_proc_root;
static struct kmem_cache *f2fs_inode_cachep;
static struct kset *f2fs_kset;

enum {
        Opt_gc_background,
        Opt_disable_roll_forward,
        Opt_norecovery,
        Opt_discard,
        Opt_noheap,
        Opt_user_xattr,
        Opt_nouser_xattr,
        Opt_acl,
        Opt_noacl,
        Opt_active_logs,
        Opt_disable_ext_identify,
        Opt_inline_xattr,
        Opt_inline_data,
        Opt_inline_dentry,
        Opt_flush_merge,
        Opt_nobarrier,
        Opt_fastboot,
        Opt_extent_cache,
        Opt_err,
};

static match_table_t f2fs_tokens = {
        {Opt_gc_background, "background_gc=%s"},
        {Opt_disable_roll_forward, "disable_roll_forward"},
        {Opt_norecovery, "norecovery"},
        {Opt_discard, "discard"},
        {Opt_noheap, "no_heap"},
        {Opt_user_xattr, "user_xattr"},
        {Opt_nouser_xattr, "nouser_xattr"},
        {Opt_acl, "acl"},
        {Opt_noacl, "noacl"},
        {Opt_active_logs, "active_logs=%u"},
        {Opt_disable_ext_identify, "disable_ext_identify"},
        {Opt_inline_xattr, "inline_xattr"},
        {Opt_inline_data, "inline_data"},
        {Opt_inline_dentry, "inline_dentry"},
        {Opt_flush_merge, "flush_merge"},
        {Opt_nobarrier, "nobarrier"},
        {Opt_fastboot, "fastboot"},
        {Opt_extent_cache, "extent_cache"},
        {Opt_err, NULL},
};

/* Sysfs support for f2fs */
enum {
        GC_THREAD,      /* struct f2fs_gc_thread */
        SM_INFO,        /* struct f2fs_sm_info */
        NM_INFO,        /* struct f2fs_nm_info */
        F2FS_SBI,       /* struct f2fs_sb_info */
};

struct f2fs_attr {
        struct attribute attr;
        ssize_t (*show)(struct f2fs_attr *, struct f2fs_sb_info *, char *);
        ssize_t (*store)(struct f2fs_attr *, struct f2fs_sb_info *,
                         const char *, size_t);
        int struct_type;
        int offset;
};

static unsigned char *__struct_ptr(struct f2fs_sb_info *sbi, int struct_type)
{
        if (struct_type == GC_THREAD)
                return (unsigned char *)sbi->gc_thread;
        else if (struct_type == SM_INFO)
                return (unsigned char *)SM_I(sbi);
        else if (struct_type == NM_INFO)
                return (unsigned char *)NM_I(sbi);
        else if (struct_type == F2FS_SBI)
                return (unsigned char *)sbi;
        return NULL;
}

static ssize_t f2fs_sbi_show(struct f2fs_attr *a,
                        struct f2fs_sb_info *sbi, char *buf)
{
        unsigned char *ptr = NULL;
        unsigned int *ui;

        ptr = __struct_ptr(sbi, a->struct_type);
        if (!ptr)
                return -EINVAL;

        ui = (unsigned int *)(ptr + a->offset);

        return snprintf(buf, PAGE_SIZE, "%u\n", *ui);
}

static ssize_t f2fs_sbi_store(struct f2fs_attr *a,
                        struct f2fs_sb_info *sbi,
                        const char *buf, size_t count)
{
        unsigned char *ptr;
        unsigned long t;
        unsigned int *ui;
        ssize_t ret;

        ptr = __struct_ptr(sbi, a->struct_type);
        if (!ptr)
                return -EINVAL;

        ui = (unsigned int *)(ptr + a->offset);

        ret = kstrtoul(skip_spaces(buf), 0, &t);
        if (ret < 0)
                return ret;
        *ui = t;
        return count;
}

static ssize_t f2fs_attr_show(struct kobject *kobj,
                                struct attribute *attr, char *buf)
{
        struct f2fs_sb_info *sbi = container_of(kobj, struct f2fs_sb_info,
                                                                s_kobj);
        struct f2fs_attr *a = container_of(attr, struct f2fs_attr, attr);

        return a->show ? a->show(a, sbi, buf) : 0;
}

static ssize_t f2fs_attr_store(struct kobject *kobj, struct attribute *attr,
                                                const char *buf, size_t len)
{
        struct f2fs_sb_info *sbi = container_of(kobj, struct f2fs_sb_info,
                                                                        s_kobj);
        struct f2fs_attr *a = container_of(attr, struct f2fs_attr, attr);

        return a->store ? a->store(a, sbi, buf, len) : 0;
}

static void f2fs_sb_release(struct kobject *kobj)
{
        struct f2fs_sb_info *sbi = container_of(kobj, struct f2fs_sb_info,
                                                                s_kobj);
        complete(&sbi->s_kobj_unregister);
}

#define F2FS_ATTR_OFFSET(_struct_type, _name, _mode, _show, _store, _offset) \
static struct f2fs_attr f2fs_attr_##_name = {                   \
        .attr = {.name = __stringify(_name), .mode = _mode },   \
        .show   = _show,                                        \
        .store  = _store,                                       \
        .struct_type = _struct_type,                            \
        .offset = _offset                                       \
}

#define F2FS_RW_ATTR(struct_type, struct_name, name, elname)    \
        F2FS_ATTR_OFFSET(struct_type, name, 0644,               \
                f2fs_sbi_show, f2fs_sbi_store,                  \
                offsetof(struct struct_name, elname))

F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_min_sleep_time, min_sleep_time);
F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_max_sleep_time, max_sleep_time);
F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_no_gc_sleep_time, no_gc_sleep_time);
F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_idle, gc_idle);
F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, reclaim_segments, rec_prefree_segments);
F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, max_small_discards, max_discards);
F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, batched_trim_sections, trim_sections);
F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, ipu_policy, ipu_policy);
F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, min_ipu_util, min_ipu_util);
F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, min_fsync_blocks, min_fsync_blocks);
F2FS_RW_ATTR(NM_INFO, f2fs_nm_info, ram_thresh, ram_thresh);
F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, max_victim_search, max_victim_search);
F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, dir_level, dir_level);

#define ATTR_LIST(name) (&f2fs_attr_##name.attr)
static struct attribute *f2fs_attrs[] = {
        ATTR_LIST(gc_min_sleep_time),
        ATTR_LIST(gc_max_sleep_time),
        ATTR_LIST(gc_no_gc_sleep_time),
        ATTR_LIST(gc_idle),
        ATTR_LIST(reclaim_segments),
        ATTR_LIST(max_small_discards),
        ATTR_LIST(batched_trim_sections),
        ATTR_LIST(ipu_policy),
        ATTR_LIST(min_ipu_util),
        ATTR_LIST(min_fsync_blocks),
        ATTR_LIST(max_victim_search),
        ATTR_LIST(dir_level),
        ATTR_LIST(ram_thresh),
        NULL,
};

static const struct sysfs_ops f2fs_attr_ops = {
        .show   = f2fs_attr_show,
        .store  = f2fs_attr_store,
};

static struct kobj_type f2fs_ktype = {
        .default_attrs  = f2fs_attrs,
        .sysfs_ops      = &f2fs_attr_ops,
        .release        = f2fs_sb_release,
};

void f2fs_msg(struct super_block *sb, const char *level, const char *fmt, ...)
{
        struct va_format vaf;
        va_list args;

        va_start(args, fmt);
        vaf.fmt = fmt;
        vaf.va = &args;
        printk("%sF2FS-fs (%s): %pV\n", level, sb->s_id, &vaf);
        va_end(args);
}

static void init_once(void *foo)
{
        struct f2fs_inode_info *fi = (struct f2fs_inode_info *) foo;

        inode_init_once(&fi->vfs_inode);
}

static int parse_options(struct super_block *sb, char *options)
{
        struct f2fs_sb_info *sbi = F2FS_SB(sb);
        substring_t args[MAX_OPT_ARGS];
        char *p, *name;
        int arg = 0;

        if (!options)
                return 0;

        while ((p = strsep(&options, ",")) != NULL) {
                int token;
                if (!*p)
                        continue;
                /*
                 * Initialize args struct so we know whether arg was
                 * found; some options take optional arguments.
                 */
                args[0].to = args[0].from = NULL;
                token = match_token(p, f2fs_tokens, args);

                switch (token) {
                case Opt_gc_background:
                        name = match_strdup(&args[0]);

                        if (!name)
                                return -ENOMEM;
                        if (strlen(name) == 2 && !strncmp(name, "on", 2))
                                set_opt(sbi, BG_GC);
                        else if (strlen(name) == 3 && !strncmp(name, "off", 3))
                                clear_opt(sbi, BG_GC);
                        else {
                                kfree(name);
                                return -EINVAL;
                        }
                        kfree(name);
                        break;
                case Opt_disable_roll_forward:
                        set_opt(sbi, DISABLE_ROLL_FORWARD);
                        break;
                case Opt_norecovery:
                        /* this option mounts f2fs with ro */
                        set_opt(sbi, DISABLE_ROLL_FORWARD);
                        if (!f2fs_readonly(sb))
                                return -EINVAL;
                        break;
                case Opt_discard:
                        set_opt(sbi, DISCARD);
                        break;
                case Opt_noheap:
                        set_opt(sbi, NOHEAP);
                        break;
#ifdef CONFIG_F2FS_FS_XATTR
                case Opt_user_xattr:
                        set_opt(sbi, XATTR_USER);
                        break;
                case Opt_nouser_xattr:
                        clear_opt(sbi, XATTR_USER);
                        break;
                case Opt_inline_xattr:
                        set_opt(sbi, INLINE_XATTR);
                        break;
#else
                case Opt_user_xattr:
                        f2fs_msg(sb, KERN_INFO,
                                "user_xattr options not supported");
                        break;
                case Opt_nouser_xattr:
                        f2fs_msg(sb, KERN_INFO,
                                "nouser_xattr options not supported");
                        break;
                case Opt_inline_xattr:
                        f2fs_msg(sb, KERN_INFO,
                                "inline_xattr options not supported");
                        break;
#endif
#ifdef CONFIG_F2FS_FS_POSIX_ACL
                case Opt_acl:
                        set_opt(sbi, POSIX_ACL);
                        break;
                case Opt_noacl:
                        clear_opt(sbi, POSIX_ACL);
                        break;
#else
                case Opt_acl:
                        f2fs_msg(sb, KERN_INFO, "acl options not supported");
                        break;
                case Opt_noacl:
                        f2fs_msg(sb, KERN_INFO, "noacl options not supported");
                        break;
#endif
                case Opt_active_logs:
                        if (args->from && match_int(args, &arg))
                                return -EINVAL;
                        if (arg != 2 && arg != 4 && arg != NR_CURSEG_TYPE)
                                return -EINVAL;
                        sbi->active_logs = arg;
                        break;
                case Opt_disable_ext_identify:
                        set_opt(sbi, DISABLE_EXT_IDENTIFY);
                        break;
                case Opt_inline_data:
                        set_opt(sbi, INLINE_DATA);
                        break;
                case Opt_inline_dentry:
                        set_opt(sbi, INLINE_DENTRY);
                        break;
                case Opt_flush_merge:
                        set_opt(sbi, FLUSH_MERGE);
                        break;
                case Opt_nobarrier:
                        set_opt(sbi, NOBARRIER);
                        break;
                case Opt_fastboot:
                        set_opt(sbi, FASTBOOT);
                        break;
                case Opt_extent_cache:
                        set_opt(sbi, EXTENT_CACHE);
                        break;
                default:
                        f2fs_msg(sb, KERN_ERR,
                                "Unrecognized mount option \"%s\" or missing value",
                                p);
                        return -EINVAL;
                }
        }
        return 0;
}

static struct inode *f2fs_alloc_inode(struct super_block *sb)
{
        struct f2fs_inode_info *fi;

        fi = kmem_cache_alloc(f2fs_inode_cachep, GFP_F2FS_ZERO);
        if (!fi)
                return NULL;

        init_once((void *) fi);

        /* Initialize f2fs-specific inode info */
        fi->vfs_inode.i_version = 1;
        atomic_set(&fi->dirty_pages, 0);
        fi->i_current_depth = 1;
        fi->i_advise = 0;
        rwlock_init(&fi->ext_lock);
        init_rwsem(&fi->i_sem);
        INIT_RADIX_TREE(&fi->inmem_root, GFP_NOFS);
        INIT_LIST_HEAD(&fi->inmem_pages);
        mutex_init(&fi->inmem_lock);

        set_inode_flag(fi, FI_NEW_INODE);

        if (test_opt(F2FS_SB(sb), INLINE_XATTR))
                set_inode_flag(fi, FI_INLINE_XATTR);

        /* Will be used by directory only */
        fi->i_dir_level = F2FS_SB(sb)->dir_level;

        return &fi->vfs_inode;
}

static int f2fs_drop_inode(struct inode *inode)
{
        /*
         * This is to avoid a deadlock condition like below.
         * writeback_single_inode(inode)
         *  - f2fs_write_data_page
         *    - f2fs_gc -> iput -> evict
         *       - inode_wait_for_writeback(inode)
         */
        if (!inode_unhashed(inode) && inode->i_state & I_SYNC)
                return 0;
        return generic_drop_inode(inode);
}

/*
 * f2fs_dirty_inode() is called from __mark_inode_dirty()
 *
 * We should call set_dirty_inode to write the dirty inode through write_inode.
 */
static void f2fs_dirty_inode(struct inode *inode, int flags)
{
        set_inode_flag(F2FS_I(inode), FI_DIRTY_INODE);
}

static void f2fs_i_callback(struct rcu_head *head)
{
        struct inode *inode = container_of(head, struct inode, i_rcu);
        kmem_cache_free(f2fs_inode_cachep, F2FS_I(inode));
}

static void f2fs_destroy_inode(struct inode *inode)
{
        call_rcu(&inode->i_rcu, f2fs_i_callback);
}

static void f2fs_put_super(struct super_block *sb)
{
        struct f2fs_sb_info *sbi = F2FS_SB(sb);

        if (sbi->s_proc) {
                remove_proc_entry("segment_info", sbi->s_proc);
                remove_proc_entry(sb->s_id, f2fs_proc_root);
        }
        kobject_del(&sbi->s_kobj);

        f2fs_destroy_stats(sbi);
        stop_gc_thread(sbi);

        /*
         * We don't need to do checkpoint when superblock is clean.
         * But, the previous checkpoint was not done by umount, it needs to do
         * clean checkpoint again.
         */
        if (is_sbi_flag_set(sbi, SBI_IS_DIRTY) ||
                        !is_set_ckpt_flags(F2FS_CKPT(sbi), CP_UMOUNT_FLAG)) {
                struct cp_control cpc = {
                        .reason = CP_UMOUNT,
                };
                write_checkpoint(sbi, &cpc);
        }

        /*
         * normally superblock is clean, so we need to release this.
         * In addition, EIO will skip do checkpoint, we need this as well.
         */
        release_dirty_inode(sbi);
        release_discard_addrs(sbi);

        iput(sbi->node_inode);
        iput(sbi->meta_inode);

        /* destroy f2fs internal modules */
        destroy_node_manager(sbi);
        destroy_segment_manager(sbi);

        kfree(sbi->ckpt);
        kobject_put(&sbi->s_kobj);
        wait_for_completion(&sbi->s_kobj_unregister);

        sb->s_fs_info = NULL;
        brelse(sbi->raw_super_buf);
        kfree(sbi);
}

int f2fs_sync_fs(struct super_block *sb, int sync)
{
        struct f2fs_sb_info *sbi = F2FS_SB(sb);

        trace_f2fs_sync_fs(sb, sync);

        if (sync) {
                struct cp_control cpc;

                cpc.reason = __get_cp_reason(sbi);

                mutex_lock(&sbi->gc_mutex);
                write_checkpoint(sbi, &cpc);
                mutex_unlock(&sbi->gc_mutex);
        } else {
                f2fs_balance_fs(sbi);
        }
        f2fs_trace_ios(NULL, NULL, 1);

        return 0;
}

static int f2fs_freeze(struct super_block *sb)
{
        int err;

        if (f2fs_readonly(sb))
                return 0;

        err = f2fs_sync_fs(sb, 1);
        return err;
}

static int f2fs_unfreeze(struct super_block *sb)
{
        return 0;
}

static int f2fs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
        struct super_block *sb = dentry->d_sb;
        struct f2fs_sb_info *sbi = F2FS_SB(sb);
        u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
        block_t total_count, user_block_count, start_count, ovp_count;

        total_count = le64_to_cpu(sbi->raw_super->block_count);
        user_block_count = sbi->user_block_count;
        start_count = le32_to_cpu(sbi->raw_super->segment0_blkaddr);
        ovp_count = SM_I(sbi)->ovp_segments << sbi->log_blocks_per_seg;
        buf->f_type = F2FS_SUPER_MAGIC;
        buf->f_bsize = sbi->blocksize;

        buf->f_blocks = total_count - start_count;
        buf->f_bfree = buf->f_blocks - valid_user_blocks(sbi) - ovp_count;
        buf->f_bavail = user_block_count - valid_user_blocks(sbi);

        buf->f_files = sbi->total_node_count - F2FS_RESERVED_NODE_NUM;
        buf->f_ffree = buf->f_files - valid_inode_count(sbi);

        buf->f_namelen = F2FS_NAME_LEN;
        buf->f_fsid.val[0] = (u32)id;
        buf->f_fsid.val[1] = (u32)(id >> 32);

        return 0;
}

static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
{
        struct f2fs_sb_info *sbi = F2FS_SB(root->d_sb);

        if (!f2fs_readonly(sbi->sb) && test_opt(sbi, BG_GC))
                seq_printf(seq, ",background_gc=%s", "on");
        else
                seq_printf(seq, ",background_gc=%s", "off");
        if (test_opt(sbi, DISABLE_ROLL_FORWARD))
                seq_puts(seq, ",disable_roll_forward");
        if (test_opt(sbi, DISCARD))
                seq_puts(seq, ",discard");
        if (test_opt(sbi, NOHEAP))
                seq_puts(seq, ",no_heap_alloc");
#ifdef CONFIG_F2FS_FS_XATTR
        if (test_opt(sbi, XATTR_USER))
                seq_puts(seq, ",user_xattr");
        else
                seq_puts(seq, ",nouser_xattr");
        if (test_opt(sbi, INLINE_XATTR))
                seq_puts(seq, ",inline_xattr");
#endif
#ifdef CONFIG_F2FS_FS_POSIX_ACL
        if (test_opt(sbi, POSIX_ACL))
                seq_puts(seq, ",acl");
        else
                seq_puts(seq, ",noacl");
#endif
        if (test_opt(sbi, DISABLE_EXT_IDENTIFY))
                seq_puts(seq, ",disable_ext_identify");
        if (test_opt(sbi, INLINE_DATA))
                seq_puts(seq, ",inline_data");
        if (test_opt(sbi, INLINE_DENTRY))
                seq_puts(seq, ",inline_dentry");
        if (!f2fs_readonly(sbi->sb) && test_opt(sbi, FLUSH_MERGE))
                seq_puts(seq, ",flush_merge");
        if (test_opt(sbi, NOBARRIER))
                seq_puts(seq, ",nobarrier");
        if (test_opt(sbi, FASTBOOT))
                seq_puts(seq, ",fastboot");
        if (test_opt(sbi, EXTENT_CACHE))
                seq_puts(seq, ",extent_cache");
        seq_printf(seq, ",active_logs=%u", sbi->active_logs);

        return 0;
}

static int segment_info_seq_show(struct seq_file *seq, void *offset)
{
        struct super_block *sb = seq->private;
        struct f2fs_sb_info *sbi = F2FS_SB(sb);
        unsigned int total_segs =
                        le32_to_cpu(sbi->raw_super->segment_count_main);
        int i;

        seq_puts(seq, "format: segment_type|valid_blocks\n"
                "segment_type(0:HD, 1:WD, 2:CD, 3:HN, 4:WN, 5:CN)\n");

        for (i = 0; i < total_segs; i++) {
                struct seg_entry *se = get_seg_entry(sbi, i);

                if ((i % 10) == 0)
                        seq_printf(seq, "%-5d", i);
                seq_printf(seq, "%d|%-3u", se->type,
                                        get_valid_blocks(sbi, i, 1));
                if ((i % 10) == 9 || i == (total_segs - 1))
                        seq_putc(seq, '\n');
                else
                        seq_putc(seq, ' ');
        }

        return 0;
}

static int segment_info_open_fs(struct inode *inode, struct file *file)
{
        return single_open(file, segment_info_seq_show, PDE_DATA(inode));
}

static const struct file_operations f2fs_seq_segment_info_fops = {
        .owner = THIS_MODULE,
        .open = segment_info_open_fs,
        .read = seq_read,
        .llseek = seq_lseek,
        .release = single_release,
};

static int f2fs_remount(struct super_block *sb, int *flags, char *data)
{
        struct f2fs_sb_info *sbi = F2FS_SB(sb);
        struct f2fs_mount_info org_mount_opt;
        int err, active_logs;
        bool need_restart_gc = false;
        bool need_stop_gc = false;

        sync_filesystem(sb);

        /*
         * Save the old mount options in case we
         * need to restore them.
         */
        org_mount_opt = sbi->mount_opt;
        active_logs = sbi->active_logs;

        sbi->mount_opt.opt = 0;
        sbi->active_logs = NR_CURSEG_TYPE;

        /* parse mount options */
        err = parse_options(sb, data);
        if (err)
                goto restore_opts;

        /*
         * Previous and new state of filesystem is RO,
         * so skip checking GC and FLUSH_MERGE conditions.
         */
        if (f2fs_readonly(sb) && (*flags & MS_RDONLY))
                goto skip;

        /*
         * We stop the GC thread if FS is mounted as RO
         * or if background_gc = off is passed in mount
         * option. Also sync the filesystem.
         */
        if ((*flags & MS_RDONLY) || !test_opt(sbi, BG_GC)) {
                if (sbi->gc_thread) {
                        stop_gc_thread(sbi);
                        f2fs_sync_fs(sb, 1);
                        need_restart_gc = true;
                }
        } else if (!sbi->gc_thread) {
                err = start_gc_thread(sbi);
                if (err)
                        goto restore_opts;
                need_stop_gc = true;
        }

        /*
         * We stop issue flush thread if FS is mounted as RO
         * or if flush_merge is not passed in mount option.
         */
        if ((*flags & MS_RDONLY) || !test_opt(sbi, FLUSH_MERGE)) {
                destroy_flush_cmd_control(sbi);
        } else if (!SM_I(sbi)->cmd_control_info) {
                err = create_flush_cmd_control(sbi);
                if (err)
                        goto restore_gc;
        }
skip:
        /* Update the POSIXACL Flag */
         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
                (test_opt(sbi, POSIX_ACL) ? MS_POSIXACL : 0);
        return 0;
restore_gc:
        if (need_restart_gc) {
                if (start_gc_thread(sbi))
                        f2fs_msg(sbi->sb, KERN_WARNING,
                                "background gc thread has stopped");
        } else if (need_stop_gc) {
                stop_gc_thread(sbi);
        }
restore_opts:
        sbi->mount_opt = org_mount_opt;
        sbi->active_logs = active_logs;
        return err;
}

static struct super_operations f2fs_sops = {
        .alloc_inode    = f2fs_alloc_inode,
        .drop_inode     = f2fs_drop_inode,
        .destroy_inode  = f2fs_destroy_inode,
        .write_inode    = f2fs_write_inode,
        .dirty_inode    = f2fs_dirty_inode,
        .show_options   = f2fs_show_options,
        .evict_inode    = f2fs_evict_inode,
        .put_super      = f2fs_put_super,
        .sync_fs        = f2fs_sync_fs,
        .freeze_fs      = f2fs_freeze,
        .unfreeze_fs    = f2fs_unfreeze,
        .statfs         = f2fs_statfs,
        .remount_fs     = f2fs_remount,
};

static struct inode *f2fs_nfs_get_inode(struct super_block *sb,
                u64 ino, u32 generation)
{
        struct f2fs_sb_info *sbi = F2FS_SB(sb);
        struct inode *inode;

        if (check_nid_range(sbi, ino))
                return ERR_PTR(-ESTALE);

        /*
         * f2fs_iget isn't quite right if the inode is currently unallocated!
         * However f2fs_iget currently does appropriate checks to handle stale
         * inodes so everything is OK.
         */
        inode = f2fs_iget(sb, ino);
        if (IS_ERR(inode))
                return ERR_CAST(inode);
        if (unlikely(generation && inode->i_generation != generation)) {
                /* we didn't find the right inode.. */
                iput(inode);
                return ERR_PTR(-ESTALE);
        }
        return inode;
}

static struct dentry *f2fs_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,
                                    f2fs_nfs_get_inode);
}

static struct dentry *f2fs_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,
                                    f2fs_nfs_get_inode);
}

static const struct export_operations f2fs_export_ops = {
        .fh_to_dentry = f2fs_fh_to_dentry,
        .fh_to_parent = f2fs_fh_to_parent,
        .get_parent = f2fs_get_parent,
};

static loff_t max_file_size(unsigned bits)
{
        loff_t result = (DEF_ADDRS_PER_INODE - F2FS_INLINE_XATTR_ADDRS);
        loff_t leaf_count = ADDRS_PER_BLOCK;

        /* two direct node blocks */
        result += (leaf_count * 2);

        /* two indirect node blocks */
        leaf_count *= NIDS_PER_BLOCK;
        result += (leaf_count * 2);

        /* one double indirect node block */
        leaf_count *= NIDS_PER_BLOCK;
        result += leaf_count;

        result <<= bits;
        return result;
}

static int sanity_check_raw_super(struct super_block *sb,
                        struct f2fs_super_block *raw_super)
{
        unsigned int blocksize;

        if (F2FS_SUPER_MAGIC != le32_to_cpu(raw_super->magic)) {
                f2fs_msg(sb, KERN_INFO,
                        "Magic Mismatch, valid(0x%x) - read(0x%x)",
                        F2FS_SUPER_MAGIC, le32_to_cpu(raw_super->magic));
                return 1;
        }

        /* Currently, support only 4KB page cache size */
        if (F2FS_BLKSIZE != PAGE_CACHE_SIZE) {
                f2fs_msg(sb, KERN_INFO,
                        "Invalid page_cache_size (%lu), supports only 4KB\n",
                        PAGE_CACHE_SIZE);
                return 1;
        }

        /* Currently, support only 4KB block size */
        blocksize = 1 << le32_to_cpu(raw_super->log_blocksize);
        if (blocksize != F2FS_BLKSIZE) {
                f2fs_msg(sb, KERN_INFO,
                        "Invalid blocksize (%u), supports only 4KB\n",
                        blocksize);
                return 1;
        }

        /* Currently, support 512/1024/2048/4096 bytes sector size */
        if (le32_to_cpu(raw_super->log_sectorsize) >
                                F2FS_MAX_LOG_SECTOR_SIZE ||
                le32_to_cpu(raw_super->log_sectorsize) <
                                F2FS_MIN_LOG_SECTOR_SIZE) {
                f2fs_msg(sb, KERN_INFO, "Invalid log sectorsize (%u)",
                        le32_to_cpu(raw_super->log_sectorsize));
                return 1;
        }
        if (le32_to_cpu(raw_super->log_sectors_per_block) +
                le32_to_cpu(raw_super->log_sectorsize) !=
                        F2FS_MAX_LOG_SECTOR_SIZE) {
                f2fs_msg(sb, KERN_INFO,
                        "Invalid log sectors per block(%u) log sectorsize(%u)",
                        le32_to_cpu(raw_super->log_sectors_per_block),
                        le32_to_cpu(raw_super->log_sectorsize));
                return 1;
        }
        return 0;
}

static int sanity_check_ckpt(struct f2fs_sb_info *sbi)
{
        unsigned int total, fsmeta;
        struct f2fs_super_block *raw_super = F2FS_RAW_SUPER(sbi);
        struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);

        total = le32_to_cpu(raw_super->segment_count);
        fsmeta = le32_to_cpu(raw_super->segment_count_ckpt);
        fsmeta += le32_to_cpu(raw_super->segment_count_sit);
        fsmeta += le32_to_cpu(raw_super->segment_count_nat);
        fsmeta += le32_to_cpu(ckpt->rsvd_segment_count);
        fsmeta += le32_to_cpu(raw_super->segment_count_ssa);

        if (unlikely(fsmeta >= total))
                return 1;

        if (unlikely(f2fs_cp_error(sbi))) {
                f2fs_msg(sbi->sb, KERN_ERR, "A bug case: need to run fsck");
                return 1;
        }
        return 0;
}

static void init_sb_info(struct f2fs_sb_info *sbi)
{
        struct f2fs_super_block *raw_super = sbi->raw_super;
        int i;

        sbi->log_sectors_per_block =
                le32_to_cpu(raw_super->log_sectors_per_block);
        sbi->log_blocksize = le32_to_cpu(raw_super->log_blocksize);
        sbi->blocksize = 1 << sbi->log_blocksize;
        sbi->log_blocks_per_seg = le32_to_cpu(raw_super->log_blocks_per_seg);
        sbi->blocks_per_seg = 1 << sbi->log_blocks_per_seg;
        sbi->segs_per_sec = le32_to_cpu(raw_super->segs_per_sec);
        sbi->secs_per_zone = le32_to_cpu(raw_super->secs_per_zone);
        sbi->total_sections = le32_to_cpu(raw_super->section_count);
        sbi->total_node_count =
                (le32_to_cpu(raw_super->segment_count_nat) / 2)
                        * sbi->blocks_per_seg * NAT_ENTRY_PER_BLOCK;
        sbi->root_ino_num = le32_to_cpu(raw_super->root_ino);
        sbi->node_ino_num = le32_to_cpu(raw_super->node_ino);
        sbi->meta_ino_num = le32_to_cpu(raw_super->meta_ino);
        sbi->cur_victim_sec = NULL_SECNO;
        sbi->max_victim_search = DEF_MAX_VICTIM_SEARCH;

        for (i = 0; i < NR_COUNT_TYPE; i++)
                atomic_set(&sbi->nr_pages[i], 0);

        sbi->dir_level = DEF_DIR_LEVEL;
        clear_sbi_flag(sbi, SBI_NEED_FSCK);
}

/*
 * Read f2fs raw super block.
 * Because we have two copies of super block, so read the first one at first,
 * if the first one is invalid, move to read the second one.
 */
static int read_raw_super_block(struct super_block *sb,
                        struct f2fs_super_block **raw_super,
                        struct buffer_head **raw_super_buf)
{
        int block = 0;

retry:
        *raw_super_buf = sb_bread(sb, block);
        if (!*raw_super_buf) {
                f2fs_msg(sb, KERN_ERR, "Unable to read %dth superblock",
                                block + 1);
                if (block == 0) {
                        block++;
                        goto retry;
                } else {
                        return -EIO;
                }
        }

        *raw_super = (struct f2fs_super_block *)
                ((char *)(*raw_super_buf)->b_data + F2FS_SUPER_OFFSET);

        /* sanity checking of raw super */
        if (sanity_check_raw_super(sb, *raw_super)) {
                brelse(*raw_super_buf);
                f2fs_msg(sb, KERN_ERR,
                        "Can't find valid F2FS filesystem in %dth superblock",
                                                                block + 1);
                if (block == 0) {
                        block++;
                        goto retry;
                } else {
                        return -EINVAL;
                }
        }

        return 0;
}

static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
{
        struct f2fs_sb_info *sbi;
        struct f2fs_super_block *raw_super = NULL;
        struct buffer_head *raw_super_buf;
        struct inode *root;
        long err = -EINVAL;
        bool retry = true;
        char *options = NULL;
        int i;

try_onemore:
        /* allocate memory for f2fs-specific super block info */
        sbi = kzalloc(sizeof(struct f2fs_sb_info), GFP_KERNEL);
        if (!sbi)
                return -ENOMEM;

        /* set a block size */
        if (unlikely(!sb_set_blocksize(sb, F2FS_BLKSIZE))) {
                f2fs_msg(sb, KERN_ERR, "unable to set blocksize");
                goto free_sbi;
        }

        err = read_raw_super_block(sb, &raw_super, &raw_super_buf);
        if (err)
                goto free_sbi;

        sb->s_fs_info = sbi;
        /* init some FS parameters */
        sbi->active_logs = NR_CURSEG_TYPE;

        set_opt(sbi, BG_GC);

#ifdef CONFIG_F2FS_FS_XATTR
        set_opt(sbi, XATTR_USER);
#endif
#ifdef CONFIG_F2FS_FS_POSIX_ACL
        set_opt(sbi, POSIX_ACL);
#endif
        /* parse mount options */
        options = kstrdup((const char *)data, GFP_KERNEL);
        if (data && !options) {
                err = -ENOMEM;
                goto free_sb_buf;
        }

        err = parse_options(sb, options);
        if (err)
                goto free_options;

        sb->s_maxbytes = max_file_size(le32_to_cpu(raw_super->log_blocksize));
        sb->s_max_links = F2FS_LINK_MAX;
        get_random_bytes(&sbi->s_next_generation, sizeof(u32));

        sb->s_op = &f2fs_sops;
        sb->s_xattr = f2fs_xattr_handlers;
        sb->s_export_op = &f2fs_export_ops;
        sb->s_magic = F2FS_SUPER_MAGIC;
        sb->s_time_gran = 1;
        sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
                (test_opt(sbi, POSIX_ACL) ? MS_POSIXACL : 0);
        memcpy(sb->s_uuid, raw_super->uuid, sizeof(raw_super->uuid));

        /* init f2fs-specific super block info */
        sbi->sb = sb;
        sbi->raw_super = raw_super;
        sbi->raw_super_buf = raw_super_buf;
        mutex_init(&sbi->gc_mutex);
        mutex_init(&sbi->writepages);
        mutex_init(&sbi->cp_mutex);
        init_rwsem(&sbi->node_write);
        clear_sbi_flag(sbi, SBI_POR_DOING);
        spin_lock_init(&sbi->stat_lock);

        init_rwsem(&sbi->read_io.io_rwsem);
        sbi->read_io.sbi = sbi;
        sbi->read_io.bio = NULL;
        for (i = 0; i < NR_PAGE_TYPE; i++) {
                init_rwsem(&sbi->write_io[i].io_rwsem);
                sbi->write_io[i].sbi = sbi;
                sbi->write_io[i].bio = NULL;
        }

        init_rwsem(&sbi->cp_rwsem);
        init_waitqueue_head(&sbi->cp_wait);
        init_sb_info(sbi);

        /* get an inode for meta space */
        sbi->meta_inode = f2fs_iget(sb, F2FS_META_INO(sbi));
        if (IS_ERR(sbi->meta_inode)) {
                f2fs_msg(sb, KERN_ERR, "Failed to read F2FS meta data inode");
                err = PTR_ERR(sbi->meta_inode);
                goto free_options;
        }

        err = get_valid_checkpoint(sbi);
        if (err) {
                f2fs_msg(sb, KERN_ERR, "Failed to get valid F2FS checkpoint");
                goto free_meta_inode;
        }

        /* sanity checking of checkpoint */
        err = -EINVAL;
        if (sanity_check_ckpt(sbi)) {
                f2fs_msg(sb, KERN_ERR, "Invalid F2FS checkpoint");
                goto free_cp;
        }

        sbi->total_valid_node_count =
                                le32_to_cpu(sbi->ckpt->valid_node_count);
        sbi->total_valid_inode_count =
                                le32_to_cpu(sbi->ckpt->valid_inode_count);
        sbi->user_block_count = le64_to_cpu(sbi->ckpt->user_block_count);
        sbi->total_valid_block_count =
                                le64_to_cpu(sbi->ckpt->valid_block_count);
        sbi->last_valid_block_count = sbi->total_valid_block_count;
        sbi->alloc_valid_block_count = 0;
        INIT_LIST_HEAD(&sbi->dir_inode_list);
        spin_lock_init(&sbi->dir_inode_lock);

        init_ino_entry_info(sbi);

        /* setup f2fs internal modules */
        err = build_segment_manager(sbi);
        if (err) {
                f2fs_msg(sb, KERN_ERR,
                        "Failed to initialize F2FS segment manager");
                goto free_sm;
        }
        err = build_node_manager(sbi);
        if (err) {
                f2fs_msg(sb, KERN_ERR,
                        "Failed to initialize F2FS node manager");
                goto free_nm;
        }

        build_gc_manager(sbi);

        /* get an inode for node space */
        sbi->node_inode = f2fs_iget(sb, F2FS_NODE_INO(sbi));
        if (IS_ERR(sbi->node_inode)) {
                f2fs_msg(sb, KERN_ERR, "Failed to read node inode");
                err = PTR_ERR(sbi->node_inode);
                goto free_nm;
        }

        /* if there are nt orphan nodes free them */
        recover_orphan_inodes(sbi);

        /* read root inode and dentry */
        root = f2fs_iget(sb, F2FS_ROOT_INO(sbi));
        if (IS_ERR(root)) {
                f2fs_msg(sb, KERN_ERR, "Failed to read root inode");
                err = PTR_ERR(root);
                goto free_node_inode;
        }
        if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
                iput(root);
                err = -EINVAL;
                goto free_node_inode;
        }

        sb->s_root = d_make_root(root); /* allocate root dentry */
        if (!sb->s_root) {
                err = -ENOMEM;
                goto free_root_inode;
        }

        err = f2fs_build_stats(sbi);
        if (err)
                goto free_root_inode;

        if (f2fs_proc_root)
                sbi->s_proc = proc_mkdir(sb->s_id, f2fs_proc_root);

        if (sbi->s_proc)
                proc_create_data("segment_info", S_IRUGO, sbi->s_proc,
                                 &f2fs_seq_segment_info_fops, sb);

        if (test_opt(sbi, DISCARD)) {
                struct request_queue *q = bdev_get_queue(sb->s_bdev);
                if (!blk_queue_discard(q))
                        f2fs_msg(sb, KERN_WARNING,
                                        "mounting with \"discard\" option, but "
                                        "the device does not support discard");
        }

        sbi->s_kobj.kset = f2fs_kset;
        init_completion(&sbi->s_kobj_unregister);
        err = kobject_init_and_add(&sbi->s_kobj, &f2fs_ktype, NULL,
                                                        "%s", sb->s_id);
        if (err)
                goto free_proc;

        if (!retry)
                set_sbi_flag(sbi, SBI_NEED_FSCK);

        /* recover fsynced data */
        if (!test_opt(sbi, DISABLE_ROLL_FORWARD)) {
                /*
                 * mount should be failed, when device has readonly mode, and
                 * previous checkpoint was not done by clean system shutdown.
                 */
                if (bdev_read_only(sb->s_bdev) &&
                                !is_set_ckpt_flags(sbi->ckpt, CP_UMOUNT_FLAG)) {
                        err = -EROFS;
                        goto free_kobj;
                }
                err = recover_fsync_data(sbi);
                if (err) {
                        f2fs_msg(sb, KERN_ERR,
                                "Cannot recover all fsync data errno=%ld", err);
                        goto free_kobj;
                }
        }

        /*
         * If filesystem is not mounted as read-only then
         * do start the gc_thread.
         */
        if (test_opt(sbi, BG_GC) && !f2fs_readonly(sb)) {
                /* After POR, we can run background GC thread.*/
                err = start_gc_thread(sbi);
                if (err)
                        goto free_kobj;
        }
        kfree(options);
        return 0;

free_kobj:
        kobject_del(&sbi->s_kobj);
free_proc:
        if (sbi->s_proc) {
                remove_proc_entry("segment_info", sbi->s_proc);
                remove_proc_entry(sb->s_id, f2fs_proc_root);
        }
        f2fs_destroy_stats(sbi);
free_root_inode:
        dput(sb->s_root);
        sb->s_root = NULL;
free_node_inode:
        iput(sbi->node_inode);
free_nm:
        destroy_node_manager(sbi);
free_sm:
        destroy_segment_manager(sbi);
free_cp:
        kfree(sbi->ckpt);
free_meta_inode:
        make_bad_inode(sbi->meta_inode);
        iput(sbi->meta_inode);
free_options:
        kfree(options);
free_sb_buf:
        brelse(raw_super_buf);
free_sbi:
        kfree(sbi);

        /* give only one another chance */
        if (retry) {
                retry = 0;
                shrink_dcache_sb(sb);
                goto try_onemore;
        }
        return err;
}

static struct dentry *f2fs_mount(struct file_system_type *fs_type, int flags,
                        const char *dev_name, void *data)
{
        return mount_bdev(fs_type, flags, dev_name, data, f2fs_fill_super);
}

static void kill_f2fs_super(struct super_block *sb)
{
        if (sb->s_root)
                set_sbi_flag(F2FS_SB(sb), SBI_IS_CLOSE);
        kill_block_super(sb);
}

static struct file_system_type f2fs_fs_type = {
        .owner          = THIS_MODULE,
        .name           = "f2fs",
        .mount          = f2fs_mount,
        .kill_sb        = kill_f2fs_super,
        .fs_flags       = FS_REQUIRES_DEV,
};
MODULE_ALIAS_FS("f2fs");

static int __init init_inodecache(void)
{
        f2fs_inode_cachep = f2fs_kmem_cache_create("f2fs_inode_cache",
                        sizeof(struct f2fs_inode_info));
        if (!f2fs_inode_cachep)
                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(f2fs_inode_cachep);
}

static int __init init_f2fs_fs(void)
{
        int err;

        f2fs_build_trace_ios();

        err = init_inodecache();
        if (err)
                goto fail;
        err = create_node_manager_caches();
        if (err)
                goto free_inodecache;
        err = create_segment_manager_caches();
        if (err)
                goto free_node_manager_caches;
        err = create_checkpoint_caches();
        if (err)
                goto free_segment_manager_caches;
        f2fs_kset = kset_create_and_add("f2fs", NULL, fs_kobj);
        if (!f2fs_kset) {
                err = -ENOMEM;
                goto free_checkpoint_caches;
        }
        err = register_filesystem(&f2fs_fs_type);
        if (err)
                goto free_kset;
        f2fs_create_root_stats();
        f2fs_proc_root = proc_mkdir("fs/f2fs", NULL);
        return 0;

free_kset:
        kset_unregister(f2fs_kset);
free_checkpoint_caches:
        destroy_checkpoint_caches();
free_segment_manager_caches:
        destroy_segment_manager_caches();
free_node_manager_caches:
        destroy_node_manager_caches();
free_inodecache:
        destroy_inodecache();
fail:
        return err;
}

static void __exit exit_f2fs_fs(void)
{
        remove_proc_entry("fs/f2fs", NULL);
        f2fs_destroy_root_stats();
        unregister_filesystem(&f2fs_fs_type);
        destroy_checkpoint_caches();
        destroy_segment_manager_caches();
        destroy_node_manager_caches();
        destroy_inodecache();
        kset_unregister(f2fs_kset);
        f2fs_destroy_trace_ios();
}

module_init(init_f2fs_fs)
module_exit(exit_f2fs_fs)

MODULE_AUTHOR("Samsung Electronics's Praesto Team");
MODULE_DESCRIPTION("Flash Friendly File System");
MODULE_LICENSE("GPL");