/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
 * Copyright (C) 2004-2007 Red Hat, Inc.  All rights reserved.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU General Public License version 2.
 */

#include <linux/bio.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/statfs.h>
#include <linux/seq_file.h>
#include <linux/mount.h>
#include <linux/kthread.h>
#include <linux/delay.h>
#include <linux/gfs2_ondisk.h>
#include <linux/crc32.h>
#include <linux/time.h>

#include "gfs2.h"
#include "incore.h"
#include "bmap.h"
#include "dir.h"
#include "glock.h"
#include "glops.h"
#include "inode.h"
#include "log.h"
#include "meta_io.h"
#include "quota.h"
#include "recovery.h"
#include "rgrp.h"
#include "super.h"
#include "trans.h"
#include "util.h"
#include "sys.h"
#include "xattr.h"

#define args_neq(a1, a2, x) ((a1)->ar_##x != (a2)->ar_##x)

enum {
        Opt_lockproto,
        Opt_locktable,
        Opt_hostdata,
        Opt_spectator,
        Opt_ignore_local_fs,
        Opt_localflocks,
        Opt_localcaching,
        Opt_debug,
        Opt_nodebug,
        Opt_upgrade,
        Opt_acl,
        Opt_noacl,
        Opt_quota_off,
        Opt_quota_account,
        Opt_quota_on,
        Opt_quota,
        Opt_noquota,
        Opt_suiddir,
        Opt_nosuiddir,
        Opt_data_writeback,
        Opt_data_ordered,
        Opt_meta,
        Opt_discard,
        Opt_nodiscard,
        Opt_commit,
        Opt_err_withdraw,
        Opt_err_panic,
        Opt_error,
};

static const match_table_t tokens = {
        {Opt_lockproto, "lockproto=%s"},
        {Opt_locktable, "locktable=%s"},
        {Opt_hostdata, "hostdata=%s"},
        {Opt_spectator, "spectator"},
        {Opt_ignore_local_fs, "ignore_local_fs"},
        {Opt_localflocks, "localflocks"},
        {Opt_localcaching, "localcaching"},
        {Opt_debug, "debug"},
        {Opt_nodebug, "nodebug"},
        {Opt_upgrade, "upgrade"},
        {Opt_acl, "acl"},
        {Opt_noacl, "noacl"},
        {Opt_quota_off, "quota=off"},
        {Opt_quota_account, "quota=account"},
        {Opt_quota_on, "quota=on"},
        {Opt_quota, "quota"},
        {Opt_noquota, "noquota"},
        {Opt_suiddir, "suiddir"},
        {Opt_nosuiddir, "nosuiddir"},
        {Opt_data_writeback, "data=writeback"},
        {Opt_data_ordered, "data=ordered"},
        {Opt_meta, "meta"},
        {Opt_discard, "discard"},
        {Opt_nodiscard, "nodiscard"},
        {Opt_commit, "commit=%d"},
        {Opt_err_withdraw, "errors=withdraw"},
        {Opt_err_panic, "errors=panic"},
        {Opt_error, NULL}
};

/**
 * gfs2_mount_args - Parse mount options
 * @sdp:
 * @data:
 *
 * Return: errno
 */

int gfs2_mount_args(struct gfs2_sbd *sdp, struct gfs2_args *args, char *options)
{
        char *o;
        int token;
        substring_t tmp[MAX_OPT_ARGS];
        int rv;

        /* Split the options into tokens with the "," character and
           process them */

        while (1) {
                o = strsep(&options, ",");
                if (o == NULL)
                        break;
                if (*o == '\0')
                        continue;

                token = match_token(o, tokens, tmp);
                switch (token) {
                case Opt_lockproto:
                        match_strlcpy(args->ar_lockproto, &tmp[0],
                                      GFS2_LOCKNAME_LEN);
                        break;
                case Opt_locktable:
                        match_strlcpy(args->ar_locktable, &tmp[0],
                                      GFS2_LOCKNAME_LEN);
                        break;
                case Opt_hostdata:
                        match_strlcpy(args->ar_hostdata, &tmp[0],
                                      GFS2_LOCKNAME_LEN);
                        break;
                case Opt_spectator:
                        args->ar_spectator = 1;
                        break;
                case Opt_ignore_local_fs:
                        args->ar_ignore_local_fs = 1;
                        break;
                case Opt_localflocks:
                        args->ar_localflocks = 1;
                        break;
                case Opt_localcaching:
                        args->ar_localcaching = 1;
                        break;
                case Opt_debug:
                        if (args->ar_errors == GFS2_ERRORS_PANIC) {
                                fs_info(sdp, "-o debug and -o errors=panic "
                                       "are mutually exclusive.\n");
                                return -EINVAL;
                        }
                        args->ar_debug = 1;
                        break;
                case Opt_nodebug:
                        args->ar_debug = 0;
                        break;
                case Opt_upgrade:
                        args->ar_upgrade = 1;
                        break;
                case Opt_acl:
                        args->ar_posix_acl = 1;
                        break;
                case Opt_noacl:
                        args->ar_posix_acl = 0;
                        break;
                case Opt_quota_off:
                case Opt_noquota:
                        args->ar_quota = GFS2_QUOTA_OFF;
                        break;
                case Opt_quota_account:
                        args->ar_quota = GFS2_QUOTA_ACCOUNT;
                        break;
                case Opt_quota_on:
                case Opt_quota:
                        args->ar_quota = GFS2_QUOTA_ON;
                        break;
                case Opt_suiddir:
                        args->ar_suiddir = 1;
                        break;
                case Opt_nosuiddir:
                        args->ar_suiddir = 0;
                        break;
                case Opt_data_writeback:
                        args->ar_data = GFS2_DATA_WRITEBACK;
                        break;
                case Opt_data_ordered:
                        args->ar_data = GFS2_DATA_ORDERED;
                        break;
                case Opt_meta:
                        args->ar_meta = 1;
                        break;
                case Opt_discard:
                        args->ar_discard = 1;
                        break;
                case Opt_nodiscard:
                        args->ar_discard = 0;
                        break;
                case Opt_commit:
                        rv = match_int(&tmp[0], &args->ar_commit);
                        if (rv || args->ar_commit <= 0) {
                                fs_info(sdp, "commit mount option requires a positive numeric argument\n");
                                return rv ? rv : -EINVAL;
                        }
                        break;
                case Opt_err_withdraw:
                        args->ar_errors = GFS2_ERRORS_WITHDRAW;
                        break;
                case Opt_err_panic:
                        if (args->ar_debug) {
                                fs_info(sdp, "-o debug and -o errors=panic "
                                        "are mutually exclusive.\n");
                                return -EINVAL;
                        }
                        args->ar_errors = GFS2_ERRORS_PANIC;
                        break;
                case Opt_error:
                default:
                        fs_info(sdp, "invalid mount option: %s\n", o);
                        return -EINVAL;
                }
        }

        return 0;
}

/**
 * gfs2_jindex_free - Clear all the journal index information
 * @sdp: The GFS2 superblock
 *
 */

void gfs2_jindex_free(struct gfs2_sbd *sdp)
{
        struct list_head list, *head;
        struct gfs2_jdesc *jd;
        struct gfs2_journal_extent *jext;

        spin_lock(&sdp->sd_jindex_spin);
        list_add(&list, &sdp->sd_jindex_list);
        list_del_init(&sdp->sd_jindex_list);
        sdp->sd_journals = 0;
        spin_unlock(&sdp->sd_jindex_spin);

        while (!list_empty(&list)) {
                jd = list_entry(list.next, struct gfs2_jdesc, jd_list);
                head = &jd->extent_list;
                while (!list_empty(head)) {
                        jext = list_entry(head->next,
                                          struct gfs2_journal_extent,
                                          extent_list);
                        list_del(&jext->extent_list);
                        kfree(jext);
                }
                list_del(&jd->jd_list);
                iput(jd->jd_inode);
                kfree(jd);
        }
}

static struct gfs2_jdesc *jdesc_find_i(struct list_head *head, unsigned int jid)
{
        struct gfs2_jdesc *jd;
        int found = 0;

        list_for_each_entry(jd, head, jd_list) {
                if (jd->jd_jid == jid) {
                        found = 1;
                        break;
                }
        }

        if (!found)
                jd = NULL;

        return jd;
}

struct gfs2_jdesc *gfs2_jdesc_find(struct gfs2_sbd *sdp, unsigned int jid)
{
        struct gfs2_jdesc *jd;

        spin_lock(&sdp->sd_jindex_spin);
        jd = jdesc_find_i(&sdp->sd_jindex_list, jid);
        spin_unlock(&sdp->sd_jindex_spin);

        return jd;
}

int gfs2_jdesc_check(struct gfs2_jdesc *jd)
{
        struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
        struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
        int ar;
        int error;

        if (ip->i_disksize < (8 << 20) || ip->i_disksize > (1 << 30) ||
            (ip->i_disksize & (sdp->sd_sb.sb_bsize - 1))) {
                gfs2_consist_inode(ip);
                return -EIO;
        }
        jd->jd_blocks = ip->i_disksize >> sdp->sd_sb.sb_bsize_shift;

        error = gfs2_write_alloc_required(ip, 0, ip->i_disksize, &ar);
        if (!error && ar) {
                gfs2_consist_inode(ip);
                error = -EIO;
        }

        return error;
}

/**
 * gfs2_make_fs_rw - Turn a Read-Only FS into a Read-Write one
 * @sdp: the filesystem
 *
 * Returns: errno
 */

int gfs2_make_fs_rw(struct gfs2_sbd *sdp)
{
        struct gfs2_inode *ip = GFS2_I(sdp->sd_jdesc->jd_inode);
        struct gfs2_glock *j_gl = ip->i_gl;
        struct gfs2_holder t_gh;
        struct gfs2_log_header_host head;
        int error;

        error = gfs2_glock_nq_init(sdp->sd_trans_gl, LM_ST_SHARED, 0, &t_gh);
        if (error)
                return error;

        j_gl->gl_ops->go_inval(j_gl, DIO_METADATA);

        error = gfs2_find_jhead(sdp->sd_jdesc, &head);
        if (error)
                goto fail;

        if (!(head.lh_flags & GFS2_LOG_HEAD_UNMOUNT)) {
                gfs2_consist(sdp);
                error = -EIO;
                goto fail;
        }

        /*  Initialize some head of the log stuff  */
        sdp->sd_log_sequence = head.lh_sequence + 1;
        gfs2_log_pointers_init(sdp, head.lh_blkno);

        error = gfs2_quota_init(sdp);
        if (error)
                goto fail;

        set_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);

        gfs2_glock_dq_uninit(&t_gh);

        return 0;

fail:
        t_gh.gh_flags |= GL_NOCACHE;
        gfs2_glock_dq_uninit(&t_gh);

        return error;
}

void gfs2_statfs_change_in(struct gfs2_statfs_change_host *sc, const void *buf)
{
        const struct gfs2_statfs_change *str = buf;

        sc->sc_total = be64_to_cpu(str->sc_total);
        sc->sc_free = be64_to_cpu(str->sc_free);
        sc->sc_dinodes = be64_to_cpu(str->sc_dinodes);
}

static void gfs2_statfs_change_out(const struct gfs2_statfs_change_host *sc, void *buf)
{
        struct gfs2_statfs_change *str = buf;

        str->sc_total = cpu_to_be64(sc->sc_total);
        str->sc_free = cpu_to_be64(sc->sc_free);
        str->sc_dinodes = cpu_to_be64(sc->sc_dinodes);
}

int gfs2_statfs_init(struct gfs2_sbd *sdp)
{
        struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
        struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
        struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode);
        struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
        struct buffer_head *m_bh, *l_bh;
        struct gfs2_holder gh;
        int error;

        error = gfs2_glock_nq_init(m_ip->i_gl, LM_ST_EXCLUSIVE, GL_NOCACHE,
                                   &gh);
        if (error)
                return error;

        error = gfs2_meta_inode_buffer(m_ip, &m_bh);
        if (error)
                goto out;

        if (sdp->sd_args.ar_spectator) {
                spin_lock(&sdp->sd_statfs_spin);
                gfs2_statfs_change_in(m_sc, m_bh->b_data +
                                      sizeof(struct gfs2_dinode));
                spin_unlock(&sdp->sd_statfs_spin);
        } else {
                error = gfs2_meta_inode_buffer(l_ip, &l_bh);
                if (error)
                        goto out_m_bh;

                spin_lock(&sdp->sd_statfs_spin);
                gfs2_statfs_change_in(m_sc, m_bh->b_data +
                                      sizeof(struct gfs2_dinode));
                gfs2_statfs_change_in(l_sc, l_bh->b_data +
                                      sizeof(struct gfs2_dinode));
                spin_unlock(&sdp->sd_statfs_spin);

                brelse(l_bh);
        }

out_m_bh:
        brelse(m_bh);
out:
        gfs2_glock_dq_uninit(&gh);
        return 0;
}

void gfs2_statfs_change(struct gfs2_sbd *sdp, s64 total, s64 free,
                        s64 dinodes)
{
        struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode);
        struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
        struct buffer_head *l_bh;
        int error;

        error = gfs2_meta_inode_buffer(l_ip, &l_bh);
        if (error)
                return;

        gfs2_trans_add_bh(l_ip->i_gl, l_bh, 1);

        spin_lock(&sdp->sd_statfs_spin);
        l_sc->sc_total += total;
        l_sc->sc_free += free;
        l_sc->sc_dinodes += dinodes;
        gfs2_statfs_change_out(l_sc, l_bh->b_data + sizeof(struct gfs2_dinode));
        spin_unlock(&sdp->sd_statfs_spin);

        brelse(l_bh);
}

void update_statfs(struct gfs2_sbd *sdp, struct buffer_head *m_bh,
                   struct buffer_head *l_bh)
{
        struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
        struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode);
        struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
        struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;

        gfs2_trans_add_bh(l_ip->i_gl, l_bh, 1);

        spin_lock(&sdp->sd_statfs_spin);
        m_sc->sc_total += l_sc->sc_total;
        m_sc->sc_free += l_sc->sc_free;
        m_sc->sc_dinodes += l_sc->sc_dinodes;
        memset(l_sc, 0, sizeof(struct gfs2_statfs_change));
        memset(l_bh->b_data + sizeof(struct gfs2_dinode),
               0, sizeof(struct gfs2_statfs_change));
        spin_unlock(&sdp->sd_statfs_spin);

        gfs2_trans_add_bh(m_ip->i_gl, m_bh, 1);
        gfs2_statfs_change_out(m_sc, m_bh->b_data + sizeof(struct gfs2_dinode));
}

int gfs2_statfs_sync(struct gfs2_sbd *sdp)
{
        struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
        struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode);
        struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
        struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
        struct gfs2_holder gh;
        struct buffer_head *m_bh, *l_bh;
        int error;

        error = gfs2_glock_nq_init(m_ip->i_gl, LM_ST_EXCLUSIVE, GL_NOCACHE,
                                   &gh);
        if (error)
                return error;

        error = gfs2_meta_inode_buffer(m_ip, &m_bh);
        if (error)
                goto out;

        spin_lock(&sdp->sd_statfs_spin);
        gfs2_statfs_change_in(m_sc, m_bh->b_data +
                              sizeof(struct gfs2_dinode));
        if (!l_sc->sc_total && !l_sc->sc_free && !l_sc->sc_dinodes) {
                spin_unlock(&sdp->sd_statfs_spin);
                goto out_bh;
        }
        spin_unlock(&sdp->sd_statfs_spin);

        error = gfs2_meta_inode_buffer(l_ip, &l_bh);
        if (error)
                goto out_bh;

        error = gfs2_trans_begin(sdp, 2 * RES_DINODE, 0);
        if (error)
                goto out_bh2;

        update_statfs(sdp, m_bh, l_bh);

        gfs2_trans_end(sdp);

out_bh2:
        brelse(l_bh);
out_bh:
        brelse(m_bh);
out:
        gfs2_glock_dq_uninit(&gh);
        return error;
}

struct lfcc {
        struct list_head list;
        struct gfs2_holder gh;
};

/**
 * gfs2_lock_fs_check_clean - Stop all writes to the FS and check that all
 *                            journals are clean
 * @sdp: the file system
 * @state: the state to put the transaction lock into
 * @t_gh: the hold on the transaction lock
 *
 * Returns: errno
 */

static int gfs2_lock_fs_check_clean(struct gfs2_sbd *sdp,
                                    struct gfs2_holder *t_gh)
{
        struct gfs2_inode *ip;
        struct gfs2_jdesc *jd;
        struct lfcc *lfcc;
        LIST_HEAD(list);
        struct gfs2_log_header_host lh;
        int error;

        list_for_each_entry(jd, &sdp->sd_jindex_list, jd_list) {
                lfcc = kmalloc(sizeof(struct lfcc), GFP_KERNEL);
                if (!lfcc) {
                        error = -ENOMEM;
                        goto out;
                }
                ip = GFS2_I(jd->jd_inode);
                error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &lfcc->gh);
                if (error) {
                        kfree(lfcc);
                        goto out;
                }
                list_add(&lfcc->list, &list);
        }

        error = gfs2_glock_nq_init(sdp->sd_trans_gl, LM_ST_DEFERRED,
                                   GL_NOCACHE, t_gh);

        list_for_each_entry(jd, &sdp->sd_jindex_list, jd_list) {
                error = gfs2_jdesc_check(jd);
                if (error)
                        break;
                error = gfs2_find_jhead(jd, &lh);
                if (error)
                        break;
                if (!(lh.lh_flags & GFS2_LOG_HEAD_UNMOUNT)) {
                        error = -EBUSY;
                        break;
                }
        }

        if (error)
                gfs2_glock_dq_uninit(t_gh);

out:
        while (!list_empty(&list)) {
                lfcc = list_entry(list.next, struct lfcc, list);
                list_del(&lfcc->list);
                gfs2_glock_dq_uninit(&lfcc->gh);
                kfree(lfcc);
        }
        return error;
}

/**
 * gfs2_freeze_fs - freezes the file system
 * @sdp: the file system
 *
 * This function flushes data and meta data for all machines by
 * aquiring the transaction log exclusively.  All journals are
 * ensured to be in a clean state as well.
 *
 * Returns: errno
 */

int gfs2_freeze_fs(struct gfs2_sbd *sdp)
{
        int error = 0;

        mutex_lock(&sdp->sd_freeze_lock);

        if (!sdp->sd_freeze_count++) {
                error = gfs2_lock_fs_check_clean(sdp, &sdp->sd_freeze_gh);
                if (error)
                        sdp->sd_freeze_count--;
        }

        mutex_unlock(&sdp->sd_freeze_lock);

        return error;
}

/**
 * gfs2_unfreeze_fs - unfreezes the file system
 * @sdp: the file system
 *
 * This function allows the file system to proceed by unlocking
 * the exclusively held transaction lock.  Other GFS2 nodes are
 * now free to acquire the lock shared and go on with their lives.
 *
 */

void gfs2_unfreeze_fs(struct gfs2_sbd *sdp)
{
        mutex_lock(&sdp->sd_freeze_lock);

        if (sdp->sd_freeze_count && !--sdp->sd_freeze_count)
                gfs2_glock_dq_uninit(&sdp->sd_freeze_gh);

        mutex_unlock(&sdp->sd_freeze_lock);
}


/**
 * gfs2_write_inode - Make sure the inode is stable on the disk
 * @inode: The inode
 * @sync: synchronous write flag
 *
 * Returns: errno
 */

static int gfs2_write_inode(struct inode *inode, int sync)
{
        struct gfs2_inode *ip = GFS2_I(inode);
        struct gfs2_sbd *sdp = GFS2_SB(inode);
        struct gfs2_holder gh;
        struct buffer_head *bh;
        struct timespec atime;
        struct gfs2_dinode *di;
        int ret = 0;

        /* Check this is a "normal" inode, etc */
        if (!test_bit(GIF_USER, &ip->i_flags) ||
            (current->flags & PF_MEMALLOC))
                return 0;
        ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
        if (ret)
                goto do_flush;
        ret = gfs2_trans_begin(sdp, RES_DINODE, 0);
        if (ret)
                goto do_unlock;
        ret = gfs2_meta_inode_buffer(ip, &bh);
        if (ret == 0) {
                di = (struct gfs2_dinode *)bh->b_data;
                atime.tv_sec = be64_to_cpu(di->di_atime);
                atime.tv_nsec = be32_to_cpu(di->di_atime_nsec);
                if (timespec_compare(&inode->i_atime, &atime) > 0) {
                        gfs2_trans_add_bh(ip->i_gl, bh, 1);
                        gfs2_dinode_out(ip, bh->b_data);
                }
                brelse(bh);
        }
        gfs2_trans_end(sdp);
do_unlock:
        gfs2_glock_dq_uninit(&gh);
do_flush:
        if (sync != 0)
                gfs2_log_flush(GFS2_SB(inode), ip->i_gl);
        return ret;
}

/**
 * gfs2_make_fs_ro - Turn a Read-Write FS into a Read-Only one
 * @sdp: the filesystem
 *
 * Returns: errno
 */

static int gfs2_make_fs_ro(struct gfs2_sbd *sdp)
{
        struct gfs2_holder t_gh;
        int error;

        flush_workqueue(gfs2_delete_workqueue);
        gfs2_quota_sync(sdp);
        gfs2_statfs_sync(sdp);

        error = gfs2_glock_nq_init(sdp->sd_trans_gl, LM_ST_SHARED, GL_NOCACHE,
                                   &t_gh);
        if (error && !test_bit(SDF_SHUTDOWN, &sdp->sd_flags))
                return error;

        gfs2_meta_syncfs(sdp);
        gfs2_log_shutdown(sdp);

        clear_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);

        if (t_gh.gh_gl)
                gfs2_glock_dq_uninit(&t_gh);

        gfs2_quota_cleanup(sdp);

        return error;
}

static int gfs2_umount_recovery_wait(void *word)
{
        schedule();
        return 0;
}

/**
 * gfs2_put_super - Unmount the filesystem
 * @sb: The VFS superblock
 *
 */

static void gfs2_put_super(struct super_block *sb)
{
        struct gfs2_sbd *sdp = sb->s_fs_info;
        int error;
        struct gfs2_jdesc *jd;

        /*  Unfreeze the filesystem, if we need to  */

        mutex_lock(&sdp->sd_freeze_lock);
        if (sdp->sd_freeze_count)
                gfs2_glock_dq_uninit(&sdp->sd_freeze_gh);
        mutex_unlock(&sdp->sd_freeze_lock);

        /* No more recovery requests */
        set_bit(SDF_NORECOVERY, &sdp->sd_flags);
        smp_mb();

        /* Wait on outstanding recovery */
restart:
        spin_lock(&sdp->sd_jindex_spin);
        list_for_each_entry(jd, &sdp->sd_jindex_list, jd_list) {
                if (!test_bit(JDF_RECOVERY, &jd->jd_flags))
                        continue;
                spin_unlock(&sdp->sd_jindex_spin);
                wait_on_bit(&jd->jd_flags, JDF_RECOVERY,
                            gfs2_umount_recovery_wait, TASK_UNINTERRUPTIBLE);
                goto restart;
        }
        spin_unlock(&sdp->sd_jindex_spin);

        kthread_stop(sdp->sd_quotad_process);
        kthread_stop(sdp->sd_logd_process);

        if (!(sb->s_flags & MS_RDONLY)) {
                error = gfs2_make_fs_ro(sdp);
                if (error)
                        gfs2_io_error(sdp);
        }
        /*  At this point, we're through modifying the disk  */

        /*  Release stuff  */

        iput(sdp->sd_jindex);
        iput(sdp->sd_statfs_inode);
        iput(sdp->sd_rindex);
        iput(sdp->sd_quota_inode);

        gfs2_glock_put(sdp->sd_rename_gl);
        gfs2_glock_put(sdp->sd_trans_gl);

        if (!sdp->sd_args.ar_spectator) {
                gfs2_glock_dq_uninit(&sdp->sd_journal_gh);
                gfs2_glock_dq_uninit(&sdp->sd_jinode_gh);
                gfs2_glock_dq_uninit(&sdp->sd_sc_gh);
                gfs2_glock_dq_uninit(&sdp->sd_qc_gh);
                iput(sdp->sd_sc_inode);
                iput(sdp->sd_qc_inode);
        }

        gfs2_glock_dq_uninit(&sdp->sd_live_gh);
        gfs2_clear_rgrpd(sdp);
        gfs2_jindex_free(sdp);
        /*  Take apart glock structures and buffer lists  */
        gfs2_gl_hash_clear(sdp);
        /*  Unmount the locking protocol  */
        gfs2_lm_unmount(sdp);

        /*  At this point, we're through participating in the lockspace  */
        gfs2_sys_fs_del(sdp);
}

/**
 * gfs2_sync_fs - sync the filesystem
 * @sb: the superblock
 *
 * Flushes the log to disk.
 */

static int gfs2_sync_fs(struct super_block *sb, int wait)
{
        if (wait && sb->s_fs_info)
                gfs2_log_flush(sb->s_fs_info, NULL);
        return 0;
}

/**
 * gfs2_freeze - prevent further writes to the filesystem
 * @sb: the VFS structure for the filesystem
 *
 */

static int gfs2_freeze(struct super_block *sb)
{
        struct gfs2_sbd *sdp = sb->s_fs_info;
        int error;

        if (test_bit(SDF_SHUTDOWN, &sdp->sd_flags))
                return -EINVAL;

        for (;;) {
                error = gfs2_freeze_fs(sdp);
                if (!error)
                        break;

                switch (error) {
                case -EBUSY:
                        fs_err(sdp, "waiting for recovery before freeze\n");
                        break;

                default:
                        fs_err(sdp, "error freezing FS: %d\n", error);
                        break;
                }

                fs_err(sdp, "retrying...\n");
                msleep(1000);
        }
        return 0;
}

/**
 * gfs2_unfreeze - reallow writes to the filesystem
 * @sb: the VFS structure for the filesystem
 *
 */

static int gfs2_unfreeze(struct super_block *sb)
{
        gfs2_unfreeze_fs(sb->s_fs_info);
        return 0;
}

/**
 * statfs_fill - fill in the sg for a given RG
 * @rgd: the RG
 * @sc: the sc structure
 *
 * Returns: 0 on success, -ESTALE if the LVB is invalid
 */

static int statfs_slow_fill(struct gfs2_rgrpd *rgd,
                            struct gfs2_statfs_change_host *sc)
{
        gfs2_rgrp_verify(rgd);
        sc->sc_total += rgd->rd_data;
        sc->sc_free += rgd->rd_free;
        sc->sc_dinodes += rgd->rd_dinodes;
        return 0;
}

/**
 * gfs2_statfs_slow - Stat a filesystem using asynchronous locking
 * @sdp: the filesystem
 * @sc: the sc info that will be returned
 *
 * Any error (other than a signal) will cause this routine to fall back
 * to the synchronous version.
 *
 * FIXME: This really shouldn't busy wait like this.
 *
 * Returns: errno
 */

static int gfs2_statfs_slow(struct gfs2_sbd *sdp, struct gfs2_statfs_change_host *sc)
{
        struct gfs2_holder ri_gh;
        struct gfs2_rgrpd *rgd_next;
        struct gfs2_holder *gha, *gh;
        unsigned int slots = 64;
        unsigned int x;
        int done;
        int error = 0, err;

        memset(sc, 0, sizeof(struct gfs2_statfs_change_host));
        gha = kcalloc(slots, sizeof(struct gfs2_holder), GFP_KERNEL);
        if (!gha)
                return -ENOMEM;

        error = gfs2_rindex_hold(sdp, &ri_gh);
        if (error)
                goto out;

        rgd_next = gfs2_rgrpd_get_first(sdp);

        for (;;) {
                done = 1;

                for (x = 0; x < slots; x++) {
                        gh = gha + x;

                        if (gh->gh_gl && gfs2_glock_poll(gh)) {
                                err = gfs2_glock_wait(gh);
                                if (err) {
                                        gfs2_holder_uninit(gh);
                                        error = err;
                                } else {
                                        if (!error)
                                                error = statfs_slow_fill(
                                                        gh->gh_gl->gl_object, sc);
                                        gfs2_glock_dq_uninit(gh);
                                }
                        }

                        if (gh->gh_gl)
                                done = 0;
                        else if (rgd_next && !error) {
                                error = gfs2_glock_nq_init(rgd_next->rd_gl,
                                                           LM_ST_SHARED,
                                                           GL_ASYNC,
                                                           gh);
                                rgd_next = gfs2_rgrpd_get_next(rgd_next);
                                done = 0;
                        }

                        if (signal_pending(current))
                                error = -ERESTARTSYS;
                }

                if (done)
                        break;

                yield();
        }

        gfs2_glock_dq_uninit(&ri_gh);

out:
        kfree(gha);
        return error;
}

/**
 * gfs2_statfs_i - Do a statfs
 * @sdp: the filesystem
 * @sg: the sg structure
 *
 * Returns: errno
 */

static int gfs2_statfs_i(struct gfs2_sbd *sdp, struct gfs2_statfs_change_host *sc)
{
        struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
        struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;

        spin_lock(&sdp->sd_statfs_spin);

        *sc = *m_sc;
        sc->sc_total += l_sc->sc_total;
        sc->sc_free += l_sc->sc_free;
        sc->sc_dinodes += l_sc->sc_dinodes;

        spin_unlock(&sdp->sd_statfs_spin);

        if (sc->sc_free < 0)
                sc->sc_free = 0;
        if (sc->sc_free > sc->sc_total)
                sc->sc_free = sc->sc_total;
        if (sc->sc_dinodes < 0)
                sc->sc_dinodes = 0;

        return 0;
}

/**
 * gfs2_statfs - Gather and return stats about the filesystem
 * @sb: The superblock
 * @statfsbuf: The buffer
 *
 * Returns: 0 on success or error code
 */

static int gfs2_statfs(struct dentry *dentry, struct kstatfs *buf)
{
        struct super_block *sb = dentry->d_inode->i_sb;
        struct gfs2_sbd *sdp = sb->s_fs_info;
        struct gfs2_statfs_change_host sc;
        int error;

        if (gfs2_tune_get(sdp, gt_statfs_slow))
                error = gfs2_statfs_slow(sdp, &sc);
        else
                error = gfs2_statfs_i(sdp, &sc);

        if (error)
                return error;

        buf->f_type = GFS2_MAGIC;
        buf->f_bsize = sdp->sd_sb.sb_bsize;
        buf->f_blocks = sc.sc_total;
        buf->f_bfree = sc.sc_free;
        buf->f_bavail = sc.sc_free;
        buf->f_files = sc.sc_dinodes + sc.sc_free;
        buf->f_ffree = sc.sc_free;
        buf->f_namelen = GFS2_FNAMESIZE;

        return 0;
}

/**
 * gfs2_remount_fs - called when the FS is remounted
 * @sb:  the filesystem
 * @flags:  the remount flags
 * @data:  extra data passed in (not used right now)
 *
 * Returns: errno
 */

static int gfs2_remount_fs(struct super_block *sb, int *flags, char *data)
{
        struct gfs2_sbd *sdp = sb->s_fs_info;
        struct gfs2_args args = sdp->sd_args; /* Default to current settings */
        struct gfs2_tune *gt = &sdp->sd_tune;
        int error;

        spin_lock(&gt->gt_spin);
        args.ar_commit = gt->gt_log_flush_secs;
        spin_unlock(&gt->gt_spin);
        error = gfs2_mount_args(sdp, &args, data);
        if (error)
                return error;

        /* Not allowed to change locking details */
        if (strcmp(args.ar_lockproto, sdp->sd_args.ar_lockproto) ||
            strcmp(args.ar_locktable, sdp->sd_args.ar_locktable) ||
            strcmp(args.ar_hostdata, sdp->sd_args.ar_hostdata))
                return -EINVAL;

        /* Some flags must not be changed */
        if (args_neq(&args, &sdp->sd_args, spectator) ||
            args_neq(&args, &sdp->sd_args, ignore_local_fs) ||
            args_neq(&args, &sdp->sd_args, localflocks) ||
            args_neq(&args, &sdp->sd_args, localcaching) ||
            args_neq(&args, &sdp->sd_args, meta))
                return -EINVAL;

        if (sdp->sd_args.ar_spectator)
                *flags |= MS_RDONLY;

        if ((sb->s_flags ^ *flags) & MS_RDONLY) {
                if (*flags & MS_RDONLY)
                        error = gfs2_make_fs_ro(sdp);
                else
                        error = gfs2_make_fs_rw(sdp);
                if (error)
                        return error;
        }

        sdp->sd_args = args;
        if (sdp->sd_args.ar_posix_acl)
                sb->s_flags |= MS_POSIXACL;
        else
                sb->s_flags &= ~MS_POSIXACL;
        spin_lock(&gt->gt_spin);
        gt->gt_log_flush_secs = args.ar_commit;
        spin_unlock(&gt->gt_spin);

        gfs2_online_uevent(sdp);
        return 0;
}

/**
 * gfs2_drop_inode - Drop an inode (test for remote unlink)
 * @inode: The inode to drop
 *
 * If we've received a callback on an iopen lock then its because a
 * remote node tried to deallocate the inode but failed due to this node
 * still having the inode open. Here we mark the link count zero
 * since we know that it must have reached zero if the GLF_DEMOTE flag
 * is set on the iopen glock. If we didn't do a disk read since the
 * remote node removed the final link then we might otherwise miss
 * this event. This check ensures that this node will deallocate the
 * inode's blocks, or alternatively pass the baton on to another
 * node for later deallocation.
 */

static void gfs2_drop_inode(struct inode *inode)
{
        struct gfs2_inode *ip = GFS2_I(inode);

        if (test_bit(GIF_USER, &ip->i_flags) && inode->i_nlink) {
                struct gfs2_glock *gl = ip->i_iopen_gh.gh_gl;
                if (gl && test_bit(GLF_DEMOTE, &gl->gl_flags))
                        clear_nlink(inode);
        }
        generic_drop_inode(inode);
}

/**
 * gfs2_clear_inode - Deallocate an inode when VFS is done with it
 * @inode: The VFS inode
 *
 */

static void gfs2_clear_inode(struct inode *inode)
{
        struct gfs2_inode *ip = GFS2_I(inode);

        /* This tells us its a "real" inode and not one which only
         * serves to contain an address space (see rgrp.c, meta_io.c)
         * which therefore doesn't have its own glocks.
         */
        if (test_bit(GIF_USER, &ip->i_flags)) {
                ip->i_gl->gl_object = NULL;
                gfs2_glock_put(ip->i_gl);
                ip->i_gl = NULL;
                if (ip->i_iopen_gh.gh_gl) {
                        ip->i_iopen_gh.gh_gl->gl_object = NULL;
                        gfs2_glock_dq_uninit(&ip->i_iopen_gh);
                }
        }
}

static int is_ancestor(const struct dentry *d1, const struct dentry *d2)
{
        do {
                if (d1 == d2)
                        return 1;
                d1 = d1->d_parent;
        } while (!IS_ROOT(d1));
        return 0;
}

/**
 * gfs2_show_options - Show mount options for /proc/mounts
 * @s: seq_file structure
 * @mnt: vfsmount
 *
 * Returns: 0 on success or error code
 */

static int gfs2_show_options(struct seq_file *s, struct vfsmount *mnt)
{
        struct gfs2_sbd *sdp = mnt->mnt_sb->s_fs_info;
        struct gfs2_args *args = &sdp->sd_args;
        int lfsecs;

        if (is_ancestor(mnt->mnt_root, sdp->sd_master_dir))
                seq_printf(s, ",meta");
        if (args->ar_lockproto[0])
                seq_printf(s, ",lockproto=%s", args->ar_lockproto);
        if (args->ar_locktable[0])
                seq_printf(s, ",locktable=%s", args->ar_locktable);
        if (args->ar_hostdata[0])
                seq_printf(s, ",hostdata=%s", args->ar_hostdata);
        if (args->ar_spectator)
                seq_printf(s, ",spectator");
        if (args->ar_ignore_local_fs)
                seq_printf(s, ",ignore_local_fs");
        if (args->ar_localflocks)
                seq_printf(s, ",localflocks");
        if (args->ar_localcaching)
                seq_printf(s, ",localcaching");
        if (args->ar_debug)
                seq_printf(s, ",debug");
        if (args->ar_upgrade)
                seq_printf(s, ",upgrade");
        if (args->ar_posix_acl)
                seq_printf(s, ",acl");
        if (args->ar_quota != GFS2_QUOTA_DEFAULT) {
                char *state;
                switch (args->ar_quota) {
                case GFS2_QUOTA_OFF:
                        state = "off";
                        break;
                case GFS2_QUOTA_ACCOUNT:
                        state = "account";
                        break;
                case GFS2_QUOTA_ON:
                        state = "on";
                        break;
                default:
                        state = "unknown";
                        break;
                }
                seq_printf(s, ",quota=%s", state);
        }
        if (args->ar_suiddir)
                seq_printf(s, ",suiddir");
        if (args->ar_data != GFS2_DATA_DEFAULT) {
                char *state;
                switch (args->ar_data) {
                case GFS2_DATA_WRITEBACK:
                        state = "writeback";
                        break;
                case GFS2_DATA_ORDERED:
                        state = "ordered";
                        break;
                default:
                        state = "unknown";
                        break;
                }
                seq_printf(s, ",data=%s", state);
        }
        if (args->ar_discard)
                seq_printf(s, ",discard");
        lfsecs = sdp->sd_tune.gt_log_flush_secs;
        if (lfsecs != 60)
                seq_printf(s, ",commit=%d", lfsecs);
        if (args->ar_errors != GFS2_ERRORS_DEFAULT) {
                const char *state;

                switch (args->ar_errors) {
                case GFS2_ERRORS_WITHDRAW:
                        state = "withdraw";
                        break;
                case GFS2_ERRORS_PANIC:
                        state = "panic";
                        break;
                default:
                        state = "unknown";
                        break;
                }
                seq_printf(s, ",errors=%s", state);
        }
        return 0;
}

/*
 * We have to (at the moment) hold the inodes main lock to cover
 * the gap between unlocking the shared lock on the iopen lock and
 * taking the exclusive lock. I'd rather do a shared -> exclusive
 * conversion on the iopen lock, but we can change that later. This
 * is safe, just less efficient.
 */

static void gfs2_delete_inode(struct inode *inode)
{
        struct gfs2_sbd *sdp = inode->i_sb->s_fs_info;
        struct gfs2_inode *ip = GFS2_I(inode);
        struct gfs2_holder gh;
        int error;

        if (!test_bit(GIF_USER, &ip->i_flags))
                goto out;

        error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
        if (unlikely(error)) {
                gfs2_glock_dq_uninit(&ip->i_iopen_gh);
                goto out;
        }

        error = gfs2_check_blk_type(sdp, ip->i_no_addr, GFS2_BLKST_UNLINKED);
        if (error)
                goto out_truncate;

        gfs2_glock_dq_wait(&ip->i_iopen_gh);
        gfs2_holder_reinit(LM_ST_EXCLUSIVE, LM_FLAG_TRY_1CB | GL_NOCACHE, &ip->i_iopen_gh);
        error = gfs2_glock_nq(&ip->i_iopen_gh);
        if (error)
                goto out_truncate;

        if (S_ISDIR(inode->i_mode) &&
            (ip->i_diskflags & GFS2_DIF_EXHASH)) {
                error = gfs2_dir_exhash_dealloc(ip);
                if (error)
                        goto out_unlock;
        }

        if (ip->i_eattr) {
                error = gfs2_ea_dealloc(ip);
                if (error)
                        goto out_unlock;
        }

        if (!gfs2_is_stuffed(ip)) {
                error = gfs2_file_dealloc(ip);
                if (error)
                        goto out_unlock;
        }

        error = gfs2_dinode_dealloc(ip);
        if (error)
                goto out_unlock;

out_truncate:
        error = gfs2_trans_begin(sdp, 0, sdp->sd_jdesc->jd_blocks);
        if (error)
                goto out_unlock;
        /* Needs to be done before glock release & also in a transaction */
        truncate_inode_pages(&inode->i_data, 0);
        gfs2_trans_end(sdp);

out_unlock:
        if (test_bit(HIF_HOLDER, &ip->i_iopen_gh.gh_iflags))
                gfs2_glock_dq(&ip->i_iopen_gh);
        gfs2_holder_uninit(&ip->i_iopen_gh);
        gfs2_glock_dq_uninit(&gh);
        if (error && error != GLR_TRYFAILED && error != -EROFS)
                fs_warn(sdp, "gfs2_delete_inode: %d\n", error);
out:
        truncate_inode_pages(&inode->i_data, 0);
        clear_inode(inode);
}

static struct inode *gfs2_alloc_inode(struct super_block *sb)
{
        struct gfs2_inode *ip;

        ip = kmem_cache_alloc(gfs2_inode_cachep, GFP_KERNEL);
        if (ip) {
                ip->i_flags = 0;
                ip->i_gl = NULL;
        }
        return &ip->i_inode;
}

static void gfs2_destroy_inode(struct inode *inode)
{
        kmem_cache_free(gfs2_inode_cachep, inode);
}

const struct super_operations gfs2_super_ops = {
        .alloc_inode            = gfs2_alloc_inode,
        .destroy_inode          = gfs2_destroy_inode,
        .write_inode            = gfs2_write_inode,
        .delete_inode           = gfs2_delete_inode,
        .put_super              = gfs2_put_super,
        .sync_fs                = gfs2_sync_fs,
        .freeze_fs              = gfs2_freeze,
        .unfreeze_fs            = gfs2_unfreeze,
        .statfs                 = gfs2_statfs,
        .remount_fs             = gfs2_remount_fs,
        .clear_inode            = gfs2_clear_inode,
        .drop_inode             = gfs2_drop_inode,
        .show_options           = gfs2_show_options,
};