super.c

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/*
 * 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 <linux/wait.h>
#include <linux/writeback.h>
#include <linux/backing-dev.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_statfs_quantum,
    Opt_statfs_percent,
    Opt_quota_quantum,
    Opt_barrier,
    Opt_nobarrier,
    Opt_rgrplvb,
    Opt_norgrplvb,
    Opt_error,
};

static const match_table_t tokens = {
    {Opt_lockproto, "lockproto=%s"},
    {Opt_locktable, "locktable=%s"},
    {Opt_hostdata, "hostdata=%s"},
    {Opt_spectator, "spectator"},
    {Opt_spectator, "norecovery"},
    {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_statfs_quantum, "statfs_quantum=%d"},
    {Opt_statfs_percent, "statfs_percent=%d"},
    {Opt_quota_quantum, "quota_quantum=%d"},
    {Opt_barrier, "barrier"},
    {Opt_nobarrier, "nobarrier"},
    {Opt_rgrplvb, "rgrplvb"},
    {Opt_norgrplvb, "norgrplvb"},
    {Opt_error, NULL}
};

int gfs2_mount_args(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:
            /* Retained for backwards compat only */
            break;
        case Opt_localflocks:
            args->ar_localflocks = 1;
            break;
        case Opt_localcaching:
            /* Retained for backwards compat only */
            break;
        case Opt_debug:
            if (args->ar_errors == GFS2_ERRORS_PANIC) {
                printk(KERN_WARNING "GFS2: -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:
            /* Retained for backwards compat only */
            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) {
                printk(KERN_WARNING "GFS2: commit mount option requires a positive numeric argument\n");
                return rv ? rv : -EINVAL;
            }
            break;
        case Opt_statfs_quantum:
            rv = match_int(&tmp[0], &args->ar_statfs_quantum);
            if (rv || args->ar_statfs_quantum < 0) {
                printk(KERN_WARNING "GFS2: statfs_quantum mount option requires a non-negative numeric argument\n");
                return rv ? rv : -EINVAL;
            }
            break;
        case Opt_quota_quantum:
            rv = match_int(&tmp[0], &args->ar_quota_quantum);
            if (rv || args->ar_quota_quantum <= 0) {
                printk(KERN_WARNING "GFS2: quota_quantum mount option requires a positive numeric argument\n");
                return rv ? rv : -EINVAL;
            }
            break;
        case Opt_statfs_percent:
            rv = match_int(&tmp[0], &args->ar_statfs_percent);
            if (rv || args->ar_statfs_percent < 0 ||
                args->ar_statfs_percent > 100) {
                printk(KERN_WARNING "statfs_percent mount option requires a numeric argument between 0 and 100\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) {
                printk(KERN_WARNING "GFS2: -o debug and -o errors=panic "
                    "are mutually exclusive.\n");
                return -EINVAL;
            }
            args->ar_errors = GFS2_ERRORS_PANIC;
            break;
        case Opt_barrier:
            args->ar_nobarrier = 0;
            break;
        case Opt_nobarrier:
            args->ar_nobarrier = 1;
            break;
        case Opt_rgrplvb:
            args->ar_rgrplvb = 1;
            break;
        case Opt_norgrplvb:
            args->ar_rgrplvb = 0;
            break;
        case Opt_error:
        default:
            printk(KERN_WARNING "GFS2: invalid mount option: %s\n", o);
            return -EINVAL;
        }
    }

    return 0;
}

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);
    u64 size = i_size_read(jd->jd_inode);

    if (gfs2_check_internal_file_size(jd->jd_inode, 8 << 20, 1 << 30))
        return -EIO;

    jd->jd_blocks = size >> sdp->sd_sb.sb_bsize_shift;

    if (gfs2_write_alloc_required(ip, 0, size)) {
        gfs2_consist_inode(ip);
        return -EIO;
    }

    return 0;
}

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 gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
    struct buffer_head *l_bh;
    s64 x, y;
    int need_sync = 0;
    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));
    if (sdp->sd_args.ar_statfs_percent) {
        x = 100 * l_sc->sc_free;
        y = m_sc->sc_free * sdp->sd_args.ar_statfs_percent;
        if (x >= y || x <= -y)
            need_sync = 1;
    }
    spin_unlock(&sdp->sd_statfs_spin);

    brelse(l_bh);
    if (need_sync)
        gfs2_wake_up_statfs(sdp);
}

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 super_block *sb, int type)
{
    struct gfs2_sbd *sdp = sb->s_fs_info;
    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);
    sdp->sd_statfs_force_sync = 0;

    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;
};

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;
}

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;
}

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);
}

void gfs2_dinode_out(const struct gfs2_inode *ip, void *buf)
{
    struct gfs2_dinode *str = buf;

    str->di_header.mh_magic = cpu_to_be32(GFS2_MAGIC);
    str->di_header.mh_type = cpu_to_be32(GFS2_METATYPE_DI);
    str->di_header.mh_format = cpu_to_be32(GFS2_FORMAT_DI);
    str->di_num.no_addr = cpu_to_be64(ip->i_no_addr);
    str->di_num.no_formal_ino = cpu_to_be64(ip->i_no_formal_ino);
    str->di_mode = cpu_to_be32(ip->i_inode.i_mode);
    str->di_uid = cpu_to_be32(ip->i_inode.i_uid);
    str->di_gid = cpu_to_be32(ip->i_inode.i_gid);
    str->di_nlink = cpu_to_be32(ip->i_inode.i_nlink);
    str->di_size = cpu_to_be64(i_size_read(&ip->i_inode));
    str->di_blocks = cpu_to_be64(gfs2_get_inode_blocks(&ip->i_inode));
    str->di_atime = cpu_to_be64(ip->i_inode.i_atime.tv_sec);
    str->di_mtime = cpu_to_be64(ip->i_inode.i_mtime.tv_sec);
    str->di_ctime = cpu_to_be64(ip->i_inode.i_ctime.tv_sec);

    str->di_goal_meta = cpu_to_be64(ip->i_goal);
    str->di_goal_data = cpu_to_be64(ip->i_goal);
    str->di_generation = cpu_to_be64(ip->i_generation);

    str->di_flags = cpu_to_be32(ip->i_diskflags);
    str->di_height = cpu_to_be16(ip->i_height);
    str->di_payload_format = cpu_to_be32(S_ISDIR(ip->i_inode.i_mode) &&
                         !(ip->i_diskflags & GFS2_DIF_EXHASH) ?
                         GFS2_FORMAT_DE : 0);
    str->di_depth = cpu_to_be16(ip->i_depth);
    str->di_entries = cpu_to_be32(ip->i_entries);

    str->di_eattr = cpu_to_be64(ip->i_eattr);
    str->di_atime_nsec = cpu_to_be32(ip->i_inode.i_atime.tv_nsec);
    str->di_mtime_nsec = cpu_to_be32(ip->i_inode.i_mtime.tv_nsec);
    str->di_ctime_nsec = cpu_to_be32(ip->i_inode.i_ctime.tv_nsec);
}

static int gfs2_write_inode(struct inode *inode, struct writeback_control *wbc)
{
    struct gfs2_inode *ip = GFS2_I(inode);
    struct gfs2_sbd *sdp = GFS2_SB(inode);
    struct address_space *metamapping = gfs2_glock2aspace(ip->i_gl);
    struct backing_dev_info *bdi = metamapping->backing_dev_info;
    int ret = 0;

    if (wbc->sync_mode == WB_SYNC_ALL)
        gfs2_log_flush(GFS2_SB(inode), ip->i_gl);
    if (bdi->dirty_exceeded)
        gfs2_ail1_flush(sdp, wbc);
    else
        filemap_fdatawrite(metamapping);
    if (wbc->sync_mode == WB_SYNC_ALL)
        ret = filemap_fdatawait(metamapping);
    if (ret)
        mark_inode_dirty_sync(inode);
    return ret;
}

static void gfs2_dirty_inode(struct inode *inode, int flags)
{
    struct gfs2_inode *ip = GFS2_I(inode);
    struct gfs2_sbd *sdp = GFS2_SB(inode);
    struct buffer_head *bh;
    struct gfs2_holder gh;
    int need_unlock = 0;
    int need_endtrans = 0;
    int ret;

    if (!(flags & (I_DIRTY_DATASYNC|I_DIRTY_SYNC)))
        return;

    if (!gfs2_glock_is_locked_by_me(ip->i_gl)) {
        ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
        if (ret) {
            fs_err(sdp, "dirty_inode: glock %d\n", ret);
            return;
        }
        need_unlock = 1;
    } else if (WARN_ON_ONCE(ip->i_gl->gl_state != LM_ST_EXCLUSIVE))
        return;

    if (current->journal_info == NULL) {
        ret = gfs2_trans_begin(sdp, RES_DINODE, 0);
        if (ret) {
            fs_err(sdp, "dirty_inode: gfs2_trans_begin %d\n", ret);
            goto out;
        }
        need_endtrans = 1;
    }

    ret = gfs2_meta_inode_buffer(ip, &bh);
    if (ret == 0) {
        gfs2_trans_add_bh(ip->i_gl, bh, 1);
        gfs2_dinode_out(ip, bh->b_data);
        brelse(bh);
    }

    if (need_endtrans)
        gfs2_trans_end(sdp);
out:
    if (need_unlock)
        gfs2_glock_dq_uninit(&gh);
}

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->sd_vfs, 0);
    gfs2_statfs_sync(sdp->sd_vfs, 0);

    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;
}

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);
}

static int gfs2_sync_fs(struct super_block *sb, int wait)
{
    struct gfs2_sbd *sdp = sb->s_fs_info;

    gfs2_quota_sync(sb, -1);
    if (wait && sdp)
        gfs2_log_flush(sdp, NULL);
    return 0;
}

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;
}

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

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;
}

static int gfs2_statfs_slow(struct gfs2_sbd *sdp, struct gfs2_statfs_change_host *sc)
{
    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;

    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();
    }

    kfree(gha);
    return error;
}

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;
}

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;

    error = gfs2_rindex_update(sdp);
    if (error)
        return 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;
}

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_logd_secs;
    args.ar_quota_quantum = gt->gt_quota_quantum;
    if (gt->gt_statfs_slow)
        args.ar_statfs_quantum = 0;
    else
        args.ar_statfs_quantum = gt->gt_statfs_quantum;
    spin_unlock(&gt->gt_spin);
    error = gfs2_mount_args(&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, localflocks) ||
        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;
    if (sdp->sd_args.ar_nobarrier)
        set_bit(SDF_NOBARRIERS, &sdp->sd_flags);
    else
        clear_bit(SDF_NOBARRIERS, &sdp->sd_flags);
    spin_lock(&gt->gt_spin);
    gt->gt_logd_secs = args.ar_commit;
    gt->gt_quota_quantum = args.ar_quota_quantum;
    if (args.ar_statfs_quantum) {
        gt->gt_statfs_slow = 0;
        gt->gt_statfs_quantum = args.ar_statfs_quantum;
    }
    else {
        gt->gt_statfs_slow = 1;
        gt->gt_statfs_quantum = 30;
    }
    spin_unlock(&gt->gt_spin);

    gfs2_online_uevent(sdp);
    return 0;
}

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

    if (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);
    }
    return generic_drop_inode(inode);
}

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;
}

static int gfs2_show_options(struct seq_file *s, struct dentry *root)
{
    struct gfs2_sbd *sdp = root->d_sb->s_fs_info;
    struct gfs2_args *args = &sdp->sd_args;
    int val;

    if (is_ancestor(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_localflocks)
        seq_printf(s, ",localflocks");
    if (args->ar_debug)
        seq_printf(s, ",debug");
    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");
    val = sdp->sd_tune.gt_logd_secs;
    if (val != 30)
        seq_printf(s, ",commit=%d", val);
    val = sdp->sd_tune.gt_statfs_quantum;
    if (val != 30)
        seq_printf(s, ",statfs_quantum=%d", val);
    else if (sdp->sd_tune.gt_statfs_slow)
        seq_puts(s, ",statfs_quantum=0");
    val = sdp->sd_tune.gt_quota_quantum;
    if (val != 60)
        seq_printf(s, ",quota_quantum=%d", val);
    if (args->ar_statfs_percent)
        seq_printf(s, ",statfs_percent=%d", args->ar_statfs_percent);
    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);
    }
    if (test_bit(SDF_NOBARRIERS, &sdp->sd_flags))
        seq_printf(s, ",nobarrier");
    if (test_bit(SDF_DEMOTE, &sdp->sd_flags))
        seq_printf(s, ",demote_interface_used");
    if (args->ar_rgrplvb)
        seq_printf(s, ",rgrplvb");
    return 0;
}

static void gfs2_final_release_pages(struct gfs2_inode *ip)
{
    struct inode *inode = &ip->i_inode;
    struct gfs2_glock *gl = ip->i_gl;

    truncate_inode_pages(gfs2_glock2aspace(ip->i_gl), 0);
    truncate_inode_pages(&inode->i_data, 0);

    if (atomic_read(&gl->gl_revokes) == 0) {
        clear_bit(GLF_LFLUSH, &gl->gl_flags);
        clear_bit(GLF_DIRTY, &gl->gl_flags);
    }
}

static int gfs2_dinode_dealloc(struct gfs2_inode *ip)
{
    struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
    struct gfs2_rgrpd *rgd;
    struct gfs2_holder gh;
    int error;

    if (gfs2_get_inode_blocks(&ip->i_inode) != 1) {
        gfs2_consist_inode(ip);
        return -EIO;
    }

    error = gfs2_rindex_update(sdp);
    if (error)
        return error;

    error = gfs2_quota_hold(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
    if (error)
        return error;

    rgd = gfs2_blk2rgrpd(sdp, ip->i_no_addr, 1);
    if (!rgd) {
        gfs2_consist_inode(ip);
        error = -EIO;
        goto out_qs;
    }

    error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_EXCLUSIVE, 0, &gh);
    if (error)
        goto out_qs;

    error = gfs2_trans_begin(sdp, RES_RG_BIT + RES_STATFS + RES_QUOTA,
                 sdp->sd_jdesc->jd_blocks);
    if (error)
        goto out_rg_gunlock;

    gfs2_free_di(rgd, ip);

    gfs2_final_release_pages(ip);

    gfs2_trans_end(sdp);

out_rg_gunlock:
    gfs2_glock_dq_uninit(&gh);
out_qs:
    gfs2_quota_unhold(ip);
    return error;
}

static void gfs2_evict_inode(struct inode *inode)
{
    struct super_block *sb = inode->i_sb;
    struct gfs2_sbd *sdp = sb->s_fs_info;
    struct gfs2_inode *ip = GFS2_I(inode);
    struct gfs2_holder gh;
    int error;

    if (inode->i_nlink || (sb->s_flags & MS_RDONLY))
        goto out;

    /* Must not read inode block until block type has been verified */
    error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_SKIP, &gh);
    if (unlikely(error)) {
        gfs2_glock_dq_uninit(&ip->i_iopen_gh);
        goto out;
    }

    if (!test_bit(GIF_ALLOC_FAILED, &ip->i_flags)) {
        error = gfs2_check_blk_type(sdp, ip->i_no_addr, GFS2_BLKST_UNLINKED);
        if (error)
            goto out_truncate;
    }

    if (test_bit(GIF_INVALID, &ip->i_flags)) {
        error = gfs2_inode_refresh(ip);
        if (error)
            goto out_truncate;
    }

    ip->i_iopen_gh.gh_flags |= GL_NOCACHE;
    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;

    /* Case 1 starts here */

    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);
    goto out_unlock;

out_truncate:
    gfs2_log_flush(sdp, ip->i_gl);
    if (test_bit(GLF_DIRTY, &ip->i_gl->gl_flags)) {
        struct address_space *metamapping = gfs2_glock2aspace(ip->i_gl);
        filemap_fdatawrite(metamapping);
        filemap_fdatawait(metamapping);
    }
    write_inode_now(inode, 1);
    gfs2_ail_flush(ip->i_gl, 0);

    /* Case 2 starts here */
    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:
    /* Error path for case 1 */
    if (gfs2_rs_active(ip->i_res))
        gfs2_rs_deltree(ip, ip->i_res);

    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_evict_inode: %d\n", error);
out:
    /* Case 3 starts here */
    truncate_inode_pages(&inode->i_data, 0);
    gfs2_rs_delete(ip);
    clear_inode(inode);
    gfs2_dir_hash_inval(ip);
    ip->i_gl->gl_object = NULL;
    flush_delayed_work(&ip->i_gl->gl_work);
    gfs2_glock_add_to_lru(ip->i_gl);
    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 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;
        ip->i_rgd = NULL;
        ip->i_res = NULL;
    }
    return &ip->i_inode;
}

static void gfs2_i_callback(struct rcu_head *head)
{
    struct inode *inode = container_of(head, struct inode, i_rcu);
    kmem_cache_free(gfs2_inode_cachep, inode);
}

static void gfs2_destroy_inode(struct inode *inode)
{
    call_rcu(&inode->i_rcu, gfs2_i_callback);
}

const struct super_operations gfs2_super_ops = {
    .alloc_inode        = gfs2_alloc_inode,
    .destroy_inode      = gfs2_destroy_inode,
    .write_inode        = gfs2_write_inode,
    .dirty_inode        = gfs2_dirty_inode,
    .evict_inode        = gfs2_evict_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,
    .drop_inode     = gfs2_drop_inode,
    .show_options       = gfs2_show_options,
};