ocfs2: Define credit counts for quota operations

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / ocfs2 / quota_global.c

/*
 *  Implementation of operations over global quota file
 */
#include <linux/spinlock.h>
#include <linux/fs.h>
#include <linux/quota.h>
#include <linux/quotaops.h>
#include <linux/dqblk_qtree.h>
#include <linux/jiffies.h>
#include <linux/writeback.h>
#include <linux/workqueue.h>

#define MLOG_MASK_PREFIX ML_QUOTA
#include <cluster/masklog.h>

#include "ocfs2_fs.h"
#include "ocfs2.h"
#include "alloc.h"
#include "blockcheck.h"
#include "inode.h"
#include "journal.h"
#include "file.h"
#include "sysfile.h"
#include "dlmglue.h"
#include "uptodate.h"
#include "quota.h"

static struct workqueue_struct *ocfs2_quota_wq = NULL;

static void qsync_work_fn(struct work_struct *work);

static void ocfs2_global_disk2memdqb(struct dquot *dquot, void *dp)
{
        struct ocfs2_global_disk_dqblk *d = dp;
        struct mem_dqblk *m = &dquot->dq_dqb;

        /* Update from disk only entries not set by the admin */
        if (!test_bit(DQ_LASTSET_B + QIF_ILIMITS_B, &dquot->dq_flags)) {
                m->dqb_ihardlimit = le64_to_cpu(d->dqb_ihardlimit);
                m->dqb_isoftlimit = le64_to_cpu(d->dqb_isoftlimit);
        }
        if (!test_bit(DQ_LASTSET_B + QIF_INODES_B, &dquot->dq_flags))
                m->dqb_curinodes = le64_to_cpu(d->dqb_curinodes);
        if (!test_bit(DQ_LASTSET_B + QIF_BLIMITS_B, &dquot->dq_flags)) {
                m->dqb_bhardlimit = le64_to_cpu(d->dqb_bhardlimit);
                m->dqb_bsoftlimit = le64_to_cpu(d->dqb_bsoftlimit);
        }
        if (!test_bit(DQ_LASTSET_B + QIF_SPACE_B, &dquot->dq_flags))
                m->dqb_curspace = le64_to_cpu(d->dqb_curspace);
        if (!test_bit(DQ_LASTSET_B + QIF_BTIME_B, &dquot->dq_flags))
                m->dqb_btime = le64_to_cpu(d->dqb_btime);
        if (!test_bit(DQ_LASTSET_B + QIF_ITIME_B, &dquot->dq_flags))
                m->dqb_itime = le64_to_cpu(d->dqb_itime);
        OCFS2_DQUOT(dquot)->dq_use_count = le32_to_cpu(d->dqb_use_count);
}

static void ocfs2_global_mem2diskdqb(void *dp, struct dquot *dquot)
{
        struct ocfs2_global_disk_dqblk *d = dp;
        struct mem_dqblk *m = &dquot->dq_dqb;

        d->dqb_id = cpu_to_le32(dquot->dq_id);
        d->dqb_use_count = cpu_to_le32(OCFS2_DQUOT(dquot)->dq_use_count);
        d->dqb_ihardlimit = cpu_to_le64(m->dqb_ihardlimit);
        d->dqb_isoftlimit = cpu_to_le64(m->dqb_isoftlimit);
        d->dqb_curinodes = cpu_to_le64(m->dqb_curinodes);
        d->dqb_bhardlimit = cpu_to_le64(m->dqb_bhardlimit);
        d->dqb_bsoftlimit = cpu_to_le64(m->dqb_bsoftlimit);
        d->dqb_curspace = cpu_to_le64(m->dqb_curspace);
        d->dqb_btime = cpu_to_le64(m->dqb_btime);
        d->dqb_itime = cpu_to_le64(m->dqb_itime);
        d->dqb_pad1 = d->dqb_pad2 = 0;
}

static int ocfs2_global_is_id(void *dp, struct dquot *dquot)
{
        struct ocfs2_global_disk_dqblk *d = dp;
        struct ocfs2_mem_dqinfo *oinfo =
                        sb_dqinfo(dquot->dq_sb, dquot->dq_type)->dqi_priv;

        if (qtree_entry_unused(&oinfo->dqi_gi, dp))
                return 0;
        return le32_to_cpu(d->dqb_id) == dquot->dq_id;
}

struct qtree_fmt_operations ocfs2_global_ops = {
        .mem2disk_dqblk = ocfs2_global_mem2diskdqb,
        .disk2mem_dqblk = ocfs2_global_disk2memdqb,
        .is_id = ocfs2_global_is_id,
};

static int ocfs2_validate_quota_block(struct super_block *sb,
                                      struct buffer_head *bh)
{
        struct ocfs2_disk_dqtrailer *dqt =
                ocfs2_block_dqtrailer(sb->s_blocksize, bh->b_data);

        mlog(0, "Validating quota block %llu\n",
             (unsigned long long)bh->b_blocknr);

        BUG_ON(!buffer_uptodate(bh));

        /*
         * If the ecc fails, we return the error but otherwise
         * leave the filesystem running.  We know any error is
         * local to this block.
         */
        return ocfs2_validate_meta_ecc(sb, bh->b_data, &dqt->dq_check);
}

int ocfs2_read_quota_block(struct inode *inode, u64 v_block,
                           struct buffer_head **bh)
{
        int rc = 0;
        struct buffer_head *tmp = *bh;

        rc = ocfs2_read_virt_blocks(inode, v_block, 1, &tmp, 0,
                                    ocfs2_validate_quota_block);
        if (rc)
                mlog_errno(rc);

        /* If ocfs2_read_virt_blocks() got us a new bh, pass it up. */
        if (!rc && !*bh)
                *bh = tmp;

        return rc;
}

static int ocfs2_get_quota_block(struct inode *inode, int block,
                                 struct buffer_head **bh)
{
        u64 pblock, pcount;
        int err;

        down_read(&OCFS2_I(inode)->ip_alloc_sem);
        err = ocfs2_extent_map_get_blocks(inode, block, &pblock, &pcount, NULL);
        up_read(&OCFS2_I(inode)->ip_alloc_sem);
        if (err) {
                mlog_errno(err);
                return err;
        }
        *bh = sb_getblk(inode->i_sb, pblock);
        if (!*bh) {
                err = -EIO;
                mlog_errno(err);
        }
        return err;;
}

/* Read data from global quotafile - avoid pagecache and such because we cannot
 * afford acquiring the locks... We use quota cluster lock to serialize
 * operations. Caller is responsible for acquiring it. */
ssize_t ocfs2_quota_read(struct super_block *sb, int type, char *data,
                         size_t len, loff_t off)
{
        struct ocfs2_mem_dqinfo *oinfo = sb_dqinfo(sb, type)->dqi_priv;
        struct inode *gqinode = oinfo->dqi_gqinode;
        loff_t i_size = i_size_read(gqinode);
        int offset = off & (sb->s_blocksize - 1);
        sector_t blk = off >> sb->s_blocksize_bits;
        int err = 0;
        struct buffer_head *bh;
        size_t toread, tocopy;

        if (off > i_size)
                return 0;
        if (off + len > i_size)
                len = i_size - off;
        toread = len;
        while (toread > 0) {
                tocopy = min_t(size_t, (sb->s_blocksize - offset), toread);
                bh = NULL;
                err = ocfs2_read_quota_block(gqinode, blk, &bh);
                if (err) {
                        mlog_errno(err);
                        return err;
                }
                memcpy(data, bh->b_data + offset, tocopy);
                brelse(bh);
                offset = 0;
                toread -= tocopy;
                data += tocopy;
                blk++;
        }
        return len;
}

/* Write to quotafile (we know the transaction is already started and has
 * enough credits) */
ssize_t ocfs2_quota_write(struct super_block *sb, int type,
                          const char *data, size_t len, loff_t off)
{
        struct mem_dqinfo *info = sb_dqinfo(sb, type);
        struct ocfs2_mem_dqinfo *oinfo = info->dqi_priv;
        struct inode *gqinode = oinfo->dqi_gqinode;
        int offset = off & (sb->s_blocksize - 1);
        sector_t blk = off >> sb->s_blocksize_bits;
        int err = 0, new = 0, ja_type;
        struct buffer_head *bh = NULL;
        handle_t *handle = journal_current_handle();

        if (!handle) {
                mlog(ML_ERROR, "Quota write (off=%llu, len=%llu) cancelled "
                     "because transaction was not started.\n",
                     (unsigned long long)off, (unsigned long long)len);
                return -EIO;
        }
        if (len > sb->s_blocksize - OCFS2_QBLK_RESERVED_SPACE - offset) {
                WARN_ON(1);
                len = sb->s_blocksize - OCFS2_QBLK_RESERVED_SPACE - offset;
        }

        mutex_lock_nested(&gqinode->i_mutex, I_MUTEX_QUOTA);
        if (gqinode->i_size < off + len) {
                loff_t rounded_end =
                                ocfs2_align_bytes_to_blocks(sb, off + len);

                down_write(&OCFS2_I(gqinode)->ip_alloc_sem);
                err = ocfs2_extend_no_holes(gqinode, rounded_end, off);
                up_write(&OCFS2_I(gqinode)->ip_alloc_sem);
                if (err < 0)
                        goto out;
                err = ocfs2_simple_size_update(gqinode,
                                               oinfo->dqi_gqi_bh,
                                               rounded_end);
                if (err < 0)
                        goto out;
                new = 1;
        }
        /* Not rewriting whole block? */
        if ((offset || len < sb->s_blocksize - OCFS2_QBLK_RESERVED_SPACE) &&
            !new) {
                err = ocfs2_read_quota_block(gqinode, blk, &bh);
                ja_type = OCFS2_JOURNAL_ACCESS_WRITE;
        } else {
                err = ocfs2_get_quota_block(gqinode, blk, &bh);
                ja_type = OCFS2_JOURNAL_ACCESS_CREATE;
        }
        if (err) {
                mlog_errno(err);
                return err;
        }
        lock_buffer(bh);
        if (new)
                memset(bh->b_data, 0, sb->s_blocksize);
        memcpy(bh->b_data + offset, data, len);
        flush_dcache_page(bh->b_page);
        set_buffer_uptodate(bh);
        unlock_buffer(bh);
        ocfs2_set_buffer_uptodate(gqinode, bh);
        err = ocfs2_journal_access_dq(handle, gqinode, bh, ja_type);
        if (err < 0) {
                brelse(bh);
                goto out;
        }
        err = ocfs2_journal_dirty(handle, bh);
        brelse(bh);
        if (err < 0)
                goto out;
out:
        if (err) {
                mutex_unlock(&gqinode->i_mutex);
                mlog_errno(err);
                return err;
        }
        gqinode->i_version++;
        ocfs2_mark_inode_dirty(handle, gqinode, oinfo->dqi_gqi_bh);
        mutex_unlock(&gqinode->i_mutex);
        return len;
}

int ocfs2_lock_global_qf(struct ocfs2_mem_dqinfo *oinfo, int ex)
{
        int status;
        struct buffer_head *bh = NULL;

        status = ocfs2_inode_lock(oinfo->dqi_gqinode, &bh, ex);
        if (status < 0)
                return status;
        spin_lock(&dq_data_lock);
        if (!oinfo->dqi_gqi_count++)
                oinfo->dqi_gqi_bh = bh;
        else
                WARN_ON(bh != oinfo->dqi_gqi_bh);
        spin_unlock(&dq_data_lock);
        return 0;
}

void ocfs2_unlock_global_qf(struct ocfs2_mem_dqinfo *oinfo, int ex)
{
        ocfs2_inode_unlock(oinfo->dqi_gqinode, ex);
        brelse(oinfo->dqi_gqi_bh);
        spin_lock(&dq_data_lock);
        if (!--oinfo->dqi_gqi_count)
                oinfo->dqi_gqi_bh = NULL;
        spin_unlock(&dq_data_lock);
}

/* Read information header from global quota file */
int ocfs2_global_read_info(struct super_block *sb, int type)
{
        struct inode *gqinode = NULL;
        unsigned int ino[MAXQUOTAS] = { USER_QUOTA_SYSTEM_INODE,
                                        GROUP_QUOTA_SYSTEM_INODE };
        struct ocfs2_global_disk_dqinfo dinfo;
        struct mem_dqinfo *info = sb_dqinfo(sb, type);
        struct ocfs2_mem_dqinfo *oinfo = info->dqi_priv;
        int status;

        mlog_entry_void();

        /* Read global header */
        gqinode = ocfs2_get_system_file_inode(OCFS2_SB(sb), ino[type],
                        OCFS2_INVALID_SLOT);
        if (!gqinode) {
                mlog(ML_ERROR, "failed to get global quota inode (type=%d)\n",
                        type);
                status = -EINVAL;
                goto out_err;
        }
        oinfo->dqi_gi.dqi_sb = sb;
        oinfo->dqi_gi.dqi_type = type;
        ocfs2_qinfo_lock_res_init(&oinfo->dqi_gqlock, oinfo);
        oinfo->dqi_gi.dqi_entry_size = sizeof(struct ocfs2_global_disk_dqblk);
        oinfo->dqi_gi.dqi_ops = &ocfs2_global_ops;
        oinfo->dqi_gqi_bh = NULL;
        oinfo->dqi_gqi_count = 0;
        oinfo->dqi_gqinode = gqinode;
        status = ocfs2_lock_global_qf(oinfo, 0);
        if (status < 0) {
                mlog_errno(status);
                goto out_err;
        }
        status = sb->s_op->quota_read(sb, type, (char *)&dinfo,
                                      sizeof(struct ocfs2_global_disk_dqinfo),
                                      OCFS2_GLOBAL_INFO_OFF);
        ocfs2_unlock_global_qf(oinfo, 0);
        if (status != sizeof(struct ocfs2_global_disk_dqinfo)) {
                mlog(ML_ERROR, "Cannot read global quota info (%d).\n",
                     status);
                if (status >= 0)
                        status = -EIO;
                mlog_errno(status);
                goto out_err;
        }
        info->dqi_bgrace = le32_to_cpu(dinfo.dqi_bgrace);
        info->dqi_igrace = le32_to_cpu(dinfo.dqi_igrace);
        oinfo->dqi_syncms = le32_to_cpu(dinfo.dqi_syncms);
        oinfo->dqi_gi.dqi_blocks = le32_to_cpu(dinfo.dqi_blocks);
        oinfo->dqi_gi.dqi_free_blk = le32_to_cpu(dinfo.dqi_free_blk);
        oinfo->dqi_gi.dqi_free_entry = le32_to_cpu(dinfo.dqi_free_entry);
        oinfo->dqi_gi.dqi_blocksize_bits = sb->s_blocksize_bits;
        oinfo->dqi_gi.dqi_usable_bs = sb->s_blocksize -
                                                OCFS2_QBLK_RESERVED_SPACE;
        oinfo->dqi_gi.dqi_qtree_depth = qtree_depth(&oinfo->dqi_gi);
        INIT_DELAYED_WORK(&oinfo->dqi_sync_work, qsync_work_fn);
        queue_delayed_work(ocfs2_quota_wq, &oinfo->dqi_sync_work,
                           msecs_to_jiffies(oinfo->dqi_syncms));

out_err:
        mlog_exit(status);
        return status;
}

/* Write information to global quota file. Expects exlusive lock on quota
 * file inode and quota info */
static int __ocfs2_global_write_info(struct super_block *sb, int type)
{
        struct mem_dqinfo *info = sb_dqinfo(sb, type);
        struct ocfs2_mem_dqinfo *oinfo = info->dqi_priv;
        struct ocfs2_global_disk_dqinfo dinfo;
        ssize_t size;

        spin_lock(&dq_data_lock);
        info->dqi_flags &= ~DQF_INFO_DIRTY;
        dinfo.dqi_bgrace = cpu_to_le32(info->dqi_bgrace);
        dinfo.dqi_igrace = cpu_to_le32(info->dqi_igrace);
        spin_unlock(&dq_data_lock);
        dinfo.dqi_syncms = cpu_to_le32(oinfo->dqi_syncms);
        dinfo.dqi_blocks = cpu_to_le32(oinfo->dqi_gi.dqi_blocks);
        dinfo.dqi_free_blk = cpu_to_le32(oinfo->dqi_gi.dqi_free_blk);
        dinfo.dqi_free_entry = cpu_to_le32(oinfo->dqi_gi.dqi_free_entry);
        size = sb->s_op->quota_write(sb, type, (char *)&dinfo,
                                     sizeof(struct ocfs2_global_disk_dqinfo),
                                     OCFS2_GLOBAL_INFO_OFF);
        if (size != sizeof(struct ocfs2_global_disk_dqinfo)) {
                mlog(ML_ERROR, "Cannot write global quota info structure\n");
                if (size >= 0)
                        size = -EIO;
                return size;
        }
        return 0;
}

int ocfs2_global_write_info(struct super_block *sb, int type)
{
        int err;
        struct ocfs2_mem_dqinfo *info = sb_dqinfo(sb, type)->dqi_priv;

        err = ocfs2_qinfo_lock(info, 1);
        if (err < 0)
                return err;
        err = __ocfs2_global_write_info(sb, type);
        ocfs2_qinfo_unlock(info, 1);
        return err;
}

/* Read in information from global quota file and acquire a reference to it.
 * dquot_acquire() has already started the transaction and locked quota file */
int ocfs2_global_read_dquot(struct dquot *dquot)
{
        int err, err2, ex = 0;
        struct ocfs2_mem_dqinfo *info =
                        sb_dqinfo(dquot->dq_sb, dquot->dq_type)->dqi_priv;

        err = ocfs2_qinfo_lock(info, 0);
        if (err < 0)
                goto out;
        err = qtree_read_dquot(&info->dqi_gi, dquot);
        if (err < 0)
                goto out_qlock;
        OCFS2_DQUOT(dquot)->dq_use_count++;
        OCFS2_DQUOT(dquot)->dq_origspace = dquot->dq_dqb.dqb_curspace;
        OCFS2_DQUOT(dquot)->dq_originodes = dquot->dq_dqb.dqb_curinodes;
        if (!dquot->dq_off) {   /* No real quota entry? */
                /* Upgrade to exclusive lock for allocation */
                ocfs2_qinfo_unlock(info, 0);
                err = ocfs2_qinfo_lock(info, 1);
                if (err < 0)
                        goto out_qlock;
                ex = 1;
        }
        err = qtree_write_dquot(&info->dqi_gi, dquot);
        if (ex && info_dirty(sb_dqinfo(dquot->dq_sb, dquot->dq_type))) {
                err2 = __ocfs2_global_write_info(dquot->dq_sb, dquot->dq_type);
                if (!err)
                        err = err2;
        }
out_qlock:
        if (ex)
                ocfs2_qinfo_unlock(info, 1);
        else
                ocfs2_qinfo_unlock(info, 0);
out:
        if (err < 0)
                mlog_errno(err);
        return err;
}

/* Sync local information about quota modifications with global quota file.
 * Caller must have started the transaction and obtained exclusive lock for
 * global quota file inode */
int __ocfs2_sync_dquot(struct dquot *dquot, int freeing)
{
        int err, err2;
        struct super_block *sb = dquot->dq_sb;
        int type = dquot->dq_type;
        struct ocfs2_mem_dqinfo *info = sb_dqinfo(sb, type)->dqi_priv;
        struct ocfs2_global_disk_dqblk dqblk;
        s64 spacechange, inodechange;
        time_t olditime, oldbtime;

        err = sb->s_op->quota_read(sb, type, (char *)&dqblk,
                                   sizeof(struct ocfs2_global_disk_dqblk),
                                   dquot->dq_off);
        if (err != sizeof(struct ocfs2_global_disk_dqblk)) {
                if (err >= 0) {
                        mlog(ML_ERROR, "Short read from global quota file "
                                       "(%u read)\n", err);
                        err = -EIO;
                }
                goto out;
        }

        /* Update space and inode usage. Get also other information from
         * global quota file so that we don't overwrite any changes there.
         * We are */
        spin_lock(&dq_data_lock);
        spacechange = dquot->dq_dqb.dqb_curspace -
                                        OCFS2_DQUOT(dquot)->dq_origspace;
        inodechange = dquot->dq_dqb.dqb_curinodes -
                                        OCFS2_DQUOT(dquot)->dq_originodes;
        olditime = dquot->dq_dqb.dqb_itime;
        oldbtime = dquot->dq_dqb.dqb_btime;
        ocfs2_global_disk2memdqb(dquot, &dqblk);
        mlog(0, "Syncing global dquot %u space %lld+%lld, inodes %lld+%lld\n",
             dquot->dq_id, dquot->dq_dqb.dqb_curspace, (long long)spacechange,
             dquot->dq_dqb.dqb_curinodes, (long long)inodechange);
        if (!test_bit(DQ_LASTSET_B + QIF_SPACE_B, &dquot->dq_flags))
                dquot->dq_dqb.dqb_curspace += spacechange;
        if (!test_bit(DQ_LASTSET_B + QIF_INODES_B, &dquot->dq_flags))
                dquot->dq_dqb.dqb_curinodes += inodechange;
        /* Set properly space grace time... */
        if (dquot->dq_dqb.dqb_bsoftlimit &&
            dquot->dq_dqb.dqb_curspace > dquot->dq_dqb.dqb_bsoftlimit) {
                if (!test_bit(DQ_LASTSET_B + QIF_BTIME_B, &dquot->dq_flags) &&
                    oldbtime > 0) {
                        if (dquot->dq_dqb.dqb_btime > 0)
                                dquot->dq_dqb.dqb_btime =
                                        min(dquot->dq_dqb.dqb_btime, oldbtime);
                        else
                                dquot->dq_dqb.dqb_btime = oldbtime;
                }
        } else {
                dquot->dq_dqb.dqb_btime = 0;
                clear_bit(DQ_BLKS_B, &dquot->dq_flags);
        }
        /* Set properly inode grace time... */
        if (dquot->dq_dqb.dqb_isoftlimit &&
            dquot->dq_dqb.dqb_curinodes > dquot->dq_dqb.dqb_isoftlimit) {
                if (!test_bit(DQ_LASTSET_B + QIF_ITIME_B, &dquot->dq_flags) &&
                    olditime > 0) {
                        if (dquot->dq_dqb.dqb_itime > 0)
                                dquot->dq_dqb.dqb_itime =
                                        min(dquot->dq_dqb.dqb_itime, olditime);
                        else
                                dquot->dq_dqb.dqb_itime = olditime;
                }
        } else {
                dquot->dq_dqb.dqb_itime = 0;
                clear_bit(DQ_INODES_B, &dquot->dq_flags);
        }
        /* All information is properly updated, clear the flags */
        __clear_bit(DQ_LASTSET_B + QIF_SPACE_B, &dquot->dq_flags);
        __clear_bit(DQ_LASTSET_B + QIF_INODES_B, &dquot->dq_flags);
        __clear_bit(DQ_LASTSET_B + QIF_BLIMITS_B, &dquot->dq_flags);
        __clear_bit(DQ_LASTSET_B + QIF_ILIMITS_B, &dquot->dq_flags);
        __clear_bit(DQ_LASTSET_B + QIF_BTIME_B, &dquot->dq_flags);
        __clear_bit(DQ_LASTSET_B + QIF_ITIME_B, &dquot->dq_flags);
        OCFS2_DQUOT(dquot)->dq_origspace = dquot->dq_dqb.dqb_curspace;
        OCFS2_DQUOT(dquot)->dq_originodes = dquot->dq_dqb.dqb_curinodes;
        spin_unlock(&dq_data_lock);
        err = ocfs2_qinfo_lock(info, freeing);
        if (err < 0) {
                mlog(ML_ERROR, "Failed to lock quota info, loosing quota write"
                               " (type=%d, id=%u)\n", dquot->dq_type,
                               (unsigned)dquot->dq_id);
                goto out;
        }
        if (freeing)
                OCFS2_DQUOT(dquot)->dq_use_count--;
        err = qtree_write_dquot(&info->dqi_gi, dquot);
        if (err < 0)
                goto out_qlock;
        if (freeing && !OCFS2_DQUOT(dquot)->dq_use_count) {
                err = qtree_release_dquot(&info->dqi_gi, dquot);
                if (info_dirty(sb_dqinfo(sb, type))) {
                        err2 = __ocfs2_global_write_info(sb, type);
                        if (!err)
                                err = err2;
                }
        }
out_qlock:
        ocfs2_qinfo_unlock(info, freeing);
out:
        if (err < 0)
                mlog_errno(err);
        return err;
}

/*
 *  Functions for periodic syncing of dquots with global file
 */
static int ocfs2_sync_dquot_helper(struct dquot *dquot, unsigned long type)
{
        handle_t *handle;
        struct super_block *sb = dquot->dq_sb;
        struct ocfs2_mem_dqinfo *oinfo = sb_dqinfo(sb, type)->dqi_priv;
        struct ocfs2_super *osb = OCFS2_SB(sb);
        int status = 0;

        mlog_entry("id=%u qtype=%u type=%lu device=%s\n", dquot->dq_id,
                   dquot->dq_type, type, sb->s_id);
        if (type != dquot->dq_type)
                goto out;
        status = ocfs2_lock_global_qf(oinfo, 1);
        if (status < 0)
                goto out;

        handle = ocfs2_start_trans(osb, OCFS2_QSYNC_CREDITS);
        if (IS_ERR(handle)) {
                status = PTR_ERR(handle);
                mlog_errno(status);
                goto out_ilock;
        }
        mutex_lock(&sb_dqopt(sb)->dqio_mutex);
        status = ocfs2_sync_dquot(dquot);
        mutex_unlock(&sb_dqopt(sb)->dqio_mutex);
        if (status < 0)
                mlog_errno(status);
        /* We have to write local structure as well... */
        dquot_mark_dquot_dirty(dquot);
        status = dquot_commit(dquot);
        if (status < 0)
                mlog_errno(status);
        ocfs2_commit_trans(osb, handle);
out_ilock:
        ocfs2_unlock_global_qf(oinfo, 1);
out:
        mlog_exit(status);
        return status;
}

static void qsync_work_fn(struct work_struct *work)
{
        struct ocfs2_mem_dqinfo *oinfo = container_of(work,
                                                      struct ocfs2_mem_dqinfo,
                                                      dqi_sync_work.work);
        struct super_block *sb = oinfo->dqi_gqinode->i_sb;

        dquot_scan_active(sb, ocfs2_sync_dquot_helper, oinfo->dqi_type);
        queue_delayed_work(ocfs2_quota_wq, &oinfo->dqi_sync_work,
                           msecs_to_jiffies(oinfo->dqi_syncms));
}

/*
 *  Wrappers for generic quota functions
 */

static int ocfs2_write_dquot(struct dquot *dquot)
{
        handle_t *handle;
        struct ocfs2_super *osb = OCFS2_SB(dquot->dq_sb);
        int status = 0;

        mlog_entry("id=%u, type=%d", dquot->dq_id, dquot->dq_type);

        handle = ocfs2_start_trans(osb, OCFS2_QWRITE_CREDITS);
        if (IS_ERR(handle)) {
                status = PTR_ERR(handle);
                mlog_errno(status);
                goto out;
        }
        status = dquot_commit(dquot);
        ocfs2_commit_trans(osb, handle);
out:
        mlog_exit(status);
        return status;
}

int ocfs2_calc_qdel_credits(struct super_block *sb, int type)
{
        struct ocfs2_mem_dqinfo *oinfo;
        int features[MAXQUOTAS] = { OCFS2_FEATURE_RO_COMPAT_USRQUOTA,
                                    OCFS2_FEATURE_RO_COMPAT_GRPQUOTA };

        if (!OCFS2_HAS_RO_COMPAT_FEATURE(sb, features[type]))
                return 0;

        oinfo = sb_dqinfo(sb, type)->dqi_priv;
        /*
         * We modify tree, leaf block, global info, local chunk header,
         * global and local inode; OCFS2_QINFO_WRITE_CREDITS already
         * accounts for inode update
         */
        return oinfo->dqi_gi.dqi_qtree_depth +
               OCFS2_QINFO_WRITE_CREDITS +
               2 * OCFS2_QUOTA_BLOCK_UPDATE_CREDITS +
               OCFS2_INODE_UPDATE_CREDITS;
}

static int ocfs2_release_dquot(struct dquot *dquot)
{
        handle_t *handle;
        struct ocfs2_mem_dqinfo *oinfo =
                        sb_dqinfo(dquot->dq_sb, dquot->dq_type)->dqi_priv;
        struct ocfs2_super *osb = OCFS2_SB(dquot->dq_sb);
        int status = 0;

        mlog_entry("id=%u, type=%d", dquot->dq_id, dquot->dq_type);

        status = ocfs2_lock_global_qf(oinfo, 1);
        if (status < 0)
                goto out;
        handle = ocfs2_start_trans(osb,
                ocfs2_calc_qdel_credits(dquot->dq_sb, dquot->dq_type));
        if (IS_ERR(handle)) {
                status = PTR_ERR(handle);
                mlog_errno(status);
                goto out_ilock;
        }
        status = dquot_release(dquot);
        ocfs2_commit_trans(osb, handle);
out_ilock:
        ocfs2_unlock_global_qf(oinfo, 1);
out:
        mlog_exit(status);
        return status;
}

int ocfs2_calc_qinit_credits(struct super_block *sb, int type)
{
        struct ocfs2_mem_dqinfo *oinfo;
        int features[MAXQUOTAS] = { OCFS2_FEATURE_RO_COMPAT_USRQUOTA,
                                    OCFS2_FEATURE_RO_COMPAT_GRPQUOTA };
        struct ocfs2_dinode *lfe, *gfe;

        if (!OCFS2_HAS_RO_COMPAT_FEATURE(sb, features[type]))
                return 0;

        oinfo = sb_dqinfo(sb, type)->dqi_priv;
        gfe = (struct ocfs2_dinode *)oinfo->dqi_gqi_bh->b_data;
        lfe = (struct ocfs2_dinode *)oinfo->dqi_lqi_bh->b_data;
        /* We can extend local file + global file. In local file we
         * can modify info, chunk header block and dquot block. In
         * global file we can modify info, tree and leaf block */
        return ocfs2_calc_extend_credits(sb, &lfe->id2.i_list, 0) +
               ocfs2_calc_extend_credits(sb, &gfe->id2.i_list, 0) +
               OCFS2_LOCAL_QINFO_WRITE_CREDITS +
               2 * OCFS2_QUOTA_BLOCK_UPDATE_CREDITS +
               oinfo->dqi_gi.dqi_qtree_depth +
               2 * OCFS2_QUOTA_BLOCK_UPDATE_CREDITS;
}

static int ocfs2_acquire_dquot(struct dquot *dquot)
{
        handle_t *handle;
        struct ocfs2_mem_dqinfo *oinfo =
                        sb_dqinfo(dquot->dq_sb, dquot->dq_type)->dqi_priv;
        struct ocfs2_super *osb = OCFS2_SB(dquot->dq_sb);
        int status = 0;

        mlog_entry("id=%u, type=%d", dquot->dq_id, dquot->dq_type);
        /* We need an exclusive lock, because we're going to update use count
         * and instantiate possibly new dquot structure */
        status = ocfs2_lock_global_qf(oinfo, 1);
        if (status < 0)
                goto out;
        handle = ocfs2_start_trans(osb,
                ocfs2_calc_qinit_credits(dquot->dq_sb, dquot->dq_type));
        if (IS_ERR(handle)) {
                status = PTR_ERR(handle);
                mlog_errno(status);
                goto out_ilock;
        }
        status = dquot_acquire(dquot);
        ocfs2_commit_trans(osb, handle);
out_ilock:
        ocfs2_unlock_global_qf(oinfo, 1);
out:
        mlog_exit(status);
        return status;
}

static int ocfs2_mark_dquot_dirty(struct dquot *dquot)
{
        unsigned long mask = (1 << (DQ_LASTSET_B + QIF_ILIMITS_B)) |
                             (1 << (DQ_LASTSET_B + QIF_BLIMITS_B)) |
                             (1 << (DQ_LASTSET_B + QIF_INODES_B)) |
                             (1 << (DQ_LASTSET_B + QIF_SPACE_B)) |
                             (1 << (DQ_LASTSET_B + QIF_BTIME_B)) |
                             (1 << (DQ_LASTSET_B + QIF_ITIME_B));
        int sync = 0;
        int status;
        struct super_block *sb = dquot->dq_sb;
        int type = dquot->dq_type;
        struct ocfs2_mem_dqinfo *oinfo = sb_dqinfo(sb, type)->dqi_priv;
        handle_t *handle;
        struct ocfs2_super *osb = OCFS2_SB(sb);

        mlog_entry("id=%u, type=%d", dquot->dq_id, type);
        dquot_mark_dquot_dirty(dquot);

        /* In case user set some limits, sync dquot immediately to global
         * quota file so that information propagates quicker */
        spin_lock(&dq_data_lock);
        if (dquot->dq_flags & mask)
                sync = 1;
        spin_unlock(&dq_data_lock);
        /* This is a slight hack but we can't afford getting global quota
         * lock if we already have a transaction started. */
        if (!sync || journal_current_handle()) {
                status = ocfs2_write_dquot(dquot);
                goto out;
        }
        status = ocfs2_lock_global_qf(oinfo, 1);
        if (status < 0)
                goto out;
        handle = ocfs2_start_trans(osb, OCFS2_QSYNC_CREDITS);
        if (IS_ERR(handle)) {
                status = PTR_ERR(handle);
                mlog_errno(status);
                goto out_ilock;
        }
        status = ocfs2_sync_dquot(dquot);
        if (status < 0) {
                mlog_errno(status);
                goto out_trans;
        }
        /* Now write updated local dquot structure */
        status = dquot_commit(dquot);
out_trans:
        ocfs2_commit_trans(osb, handle);
out_ilock:
        ocfs2_unlock_global_qf(oinfo, 1);
out:
        mlog_exit(status);
        return status;
}

/* This should happen only after set_dqinfo(). */
static int ocfs2_write_info(struct super_block *sb, int type)
{
        handle_t *handle;
        int status = 0;
        struct ocfs2_mem_dqinfo *oinfo = sb_dqinfo(sb, type)->dqi_priv;

        mlog_entry_void();

        status = ocfs2_lock_global_qf(oinfo, 1);
        if (status < 0)
                goto out;
        handle = ocfs2_start_trans(OCFS2_SB(sb), OCFS2_QINFO_WRITE_CREDITS);
        if (IS_ERR(handle)) {
                status = PTR_ERR(handle);
                mlog_errno(status);
                goto out_ilock;
        }
        status = dquot_commit_info(sb, type);
        ocfs2_commit_trans(OCFS2_SB(sb), handle);
out_ilock:
        ocfs2_unlock_global_qf(oinfo, 1);
out:
        mlog_exit(status);
        return status;
}

static struct dquot *ocfs2_alloc_dquot(struct super_block *sb, int type)
{
        struct ocfs2_dquot *dquot =
                                kmem_cache_zalloc(ocfs2_dquot_cachep, GFP_NOFS);

        if (!dquot)
                return NULL;
        return &dquot->dq_dquot;
}

static void ocfs2_destroy_dquot(struct dquot *dquot)
{
        kmem_cache_free(ocfs2_dquot_cachep, dquot);
}

struct dquot_operations ocfs2_quota_operations = {
        .initialize     = dquot_initialize,
        .drop           = dquot_drop,
        .alloc_space    = dquot_alloc_space,
        .alloc_inode    = dquot_alloc_inode,
        .free_space     = dquot_free_space,
        .free_inode     = dquot_free_inode,
        .transfer       = dquot_transfer,
        .write_dquot    = ocfs2_write_dquot,
        .acquire_dquot  = ocfs2_acquire_dquot,
        .release_dquot  = ocfs2_release_dquot,
        .mark_dirty     = ocfs2_mark_dquot_dirty,
        .write_info     = ocfs2_write_info,
        .alloc_dquot    = ocfs2_alloc_dquot,
        .destroy_dquot  = ocfs2_destroy_dquot,
};

int ocfs2_quota_setup(void)
{
        ocfs2_quota_wq = create_workqueue("o2quot");
        if (!ocfs2_quota_wq)
                return -ENOMEM;
        return 0;
}

void ocfs2_quota_shutdown(void)
{
        if (ocfs2_quota_wq) {
                flush_workqueue(ocfs2_quota_wq);
                destroy_workqueue(ocfs2_quota_wq);
                ocfs2_quota_wq = NULL;
        }
}