quota_global.c

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/*
 *  Implementation of operations over global quota file
 */
#include <linux/spinlock.h>
#include <linux/fs.h>
#include <linux/slab.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>

#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 "super.h"
#include "buffer_head_io.h"
#include "quota.h"
#include "ocfs2_trace.h"

/*
 * Locking of quotas with OCFS2 is rather complex. Here are rules that
 * should be obeyed by all the functions:
 * - any write of quota structure (either to local or global file) is protected
 *   by dqio_mutex or dquot->dq_lock.
 * - any modification of global quota file holds inode cluster lock, i_mutex,
 *   and ip_alloc_sem of the global quota file (achieved by
 *   ocfs2_lock_global_qf). It also has to hold qinfo_lock.
 * - an allocation of new blocks for local quota file is protected by
 *   its ip_alloc_sem
 *
 * A rough sketch of locking dependencies (lf = local file, gf = global file):
 * Normal filesystem operation:
 *   start_trans -> dqio_mutex -> write to lf
 * Syncing of local and global file:
 *   ocfs2_lock_global_qf -> start_trans -> dqio_mutex -> qinfo_lock ->
 *     write to gf
 *                             -> write to lf
 * Acquire dquot for the first time:
 *   dq_lock -> ocfs2_lock_global_qf -> qinfo_lock -> read from gf
 *                   -> alloc space for gf
 *                   -> start_trans -> qinfo_lock -> write to gf
 *       -> ip_alloc_sem of lf -> alloc space for lf
 *       -> write to lf
 * Release last reference to dquot:
 *   dq_lock -> ocfs2_lock_global_qf -> start_trans -> qinfo_lock -> write to gf
 *       -> write to lf
 * Note that all the above operations also hold the inode cluster lock of lf.
 * Recovery:
 *   inode cluster lock of recovered lf
 *     -> read bitmaps -> ip_alloc_sem of lf
 *     -> ocfs2_lock_global_qf -> start_trans -> dqio_mutex -> qinfo_lock ->
 *        write to gf
 */

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(from_kqid(&init_user_ns, 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_id.type)->dqi_priv;

    if (qtree_entry_unused(&oinfo->dqi_gi, dp))
        return 0;

    return qid_eq(make_kqid(&init_user_ns, dquot->dq_id.type,
                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,
};

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);

    trace_ocfs2_validate_quota_block((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_phys_block(struct inode *inode, u64 p_block,
                struct buffer_head **bhp)
{
    int rc;

    *bhp = NULL;
    rc = ocfs2_read_blocks(INODE_CACHE(inode), p_block, 1, bhp, 0,
                   ocfs2_validate_quota_block);
    if (rc)
        mlog_errno(rc);
    return rc;
}

/* 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;
    u64 pblock = 0, pcount = 0;

    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);
        if (!pcount) {
            err = ocfs2_extent_map_get_blocks(gqinode, blk, &pblock,
                              &pcount, NULL);
            if (err) {
                mlog_errno(err);
                return err;
            }
        } else {
            pcount--;
            pblock++;
        }
        bh = NULL;
        err = ocfs2_read_quota_phys_block(gqinode, pblock, &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();
    u64 pblock, pcount;

    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;
    }

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

        /* Space is already allocated in ocfs2_acquire_dquot() */
        err = ocfs2_simple_size_update(gqinode,
                           oinfo->dqi_gqi_bh,
                           rounded_end);
        if (err < 0)
            goto out;
        new = 1;
    }
    err = ocfs2_extent_map_get_blocks(gqinode, blk, &pblock, &pcount, NULL);
    if (err) {
        mlog_errno(err);
        goto out;
    }
    /* Not rewriting whole block? */
    if ((offset || len < sb->s_blocksize - OCFS2_QBLK_RESERVED_SPACE) &&
        !new) {
        err = ocfs2_read_quota_phys_block(gqinode, pblock, &bh);
        ja_type = OCFS2_JOURNAL_ACCESS_WRITE;
    } else {
        bh = sb_getblk(sb, pblock);
        if (!bh)
            err = -ENOMEM;
        ja_type = OCFS2_JOURNAL_ACCESS_CREATE;
    }
    if (err) {
        mlog_errno(err);
        goto out;
    }
    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(INODE_CACHE(gqinode), bh);
    err = ocfs2_journal_access_dq(handle, INODE_CACHE(gqinode), bh,
                      ja_type);
    if (err < 0) {
        brelse(bh);
        goto out;
    }
    ocfs2_journal_dirty(handle, bh);
    brelse(bh);
out:
    if (err) {
        mlog_errno(err);
        return err;
    }
    gqinode->i_version++;
    ocfs2_mark_inode_dirty(handle, gqinode, oinfo->dqi_gqi_bh);
    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);
    if (ex) {
        mutex_lock(&oinfo->dqi_gqinode->i_mutex);
        down_write(&OCFS2_I(oinfo->dqi_gqinode)->ip_alloc_sem);
    } else {
        down_read(&OCFS2_I(oinfo->dqi_gqinode)->ip_alloc_sem);
    }
    return 0;
}

void ocfs2_unlock_global_qf(struct ocfs2_mem_dqinfo *oinfo, int ex)
{
    if (ex) {
        up_write(&OCFS2_I(oinfo->dqi_gqinode)->ip_alloc_sem);
        mutex_unlock(&oinfo->dqi_gqinode->i_mutex);
    } else {
        up_read(&OCFS2_I(oinfo->dqi_gqinode)->ip_alloc_sem);
    }
    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;
    u64 pcount;
    int status;

    /* 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 = ocfs2_extent_map_get_blocks(gqinode, 0, &oinfo->dqi_giblk,
                         &pcount, NULL);
    if (status < 0)
        goto out_unlock;

    status = ocfs2_qinfo_lock(oinfo, 0);
    if (status < 0)
        goto out_unlock;
    status = sb->s_op->quota_read(sb, type, (char *)&dinfo,
                      sizeof(struct ocfs2_global_disk_dqinfo),
                      OCFS2_GLOBAL_INFO_OFF);
    ocfs2_qinfo_unlock(oinfo, 0);
    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);
    schedule_delayed_work(&oinfo->dqi_sync_work,
                  msecs_to_jiffies(oinfo->dqi_syncms));

out_err:
    return status;
out_unlock:
    ocfs2_unlock_global_qf(oinfo, 0);
    mlog_errno(status);
    goto out_err;
}

/* 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;
}

static int ocfs2_global_qinit_alloc(struct super_block *sb, int type)
{
    struct ocfs2_mem_dqinfo *oinfo = sb_dqinfo(sb, type)->dqi_priv;

    /*
     * We may need to allocate tree blocks and a leaf block but not the
     * root block
     */
    return oinfo->dqi_gi.dqi_qtree_depth;
}

static int ocfs2_calc_global_qinit_credits(struct super_block *sb, int type)
{
    /* We modify all the allocated blocks, tree root, info block and
     * the inode */
    return (ocfs2_global_qinit_alloc(sb, type) + 2) *
            OCFS2_QUOTA_BLOCK_UPDATE_CREDITS + 1;
}

/* 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_id.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);
    trace_ocfs2_sync_dquot(from_kqid(&init_user_ns, 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, losing quota write"
                   " (type=%d, id=%u)\n", dquot->dq_id.type,
                   (unsigned)from_kqid(&init_user_ns, 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;

    trace_ocfs2_sync_dquot_helper(from_kqid(&init_user_ns, dquot->dq_id),
                      dquot->dq_id.type,
                      type, sb->s_id);
    if (type != dquot->dq_id.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);
    if (status < 0)
        mlog_errno(status);
    /* We have to write local structure as well... */
    status = ocfs2_local_write_dquot(dquot);
    if (status < 0)
        mlog_errno(status);
    mutex_unlock(&sb_dqopt(sb)->dqio_mutex);
    ocfs2_commit_trans(osb, handle);
out_ilock:
    ocfs2_unlock_global_qf(oinfo, 1);
out:
    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);
    schedule_delayed_work(&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;

    trace_ocfs2_write_dquot(from_kqid(&init_user_ns, dquot->dq_id),
                dquot->dq_id.type);

    handle = ocfs2_start_trans(osb, OCFS2_QWRITE_CREDITS);
    if (IS_ERR(handle)) {
        status = PTR_ERR(handle);
        mlog_errno(status);
        goto out;
    }
    mutex_lock(&sb_dqopt(dquot->dq_sb)->dqio_mutex);
    status = ocfs2_local_write_dquot(dquot);
    mutex_unlock(&sb_dqopt(dquot->dq_sb)->dqio_mutex);
    ocfs2_commit_trans(osb, handle);
out:
    return status;
}

static int ocfs2_calc_qdel_credits(struct super_block *sb, int type)
{
    struct ocfs2_mem_dqinfo *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 + 2) *
           OCFS2_QUOTA_BLOCK_UPDATE_CREDITS +
           OCFS2_QINFO_WRITE_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_id.type)->dqi_priv;
    struct ocfs2_super *osb = OCFS2_SB(dquot->dq_sb);
    int status = 0;

    trace_ocfs2_release_dquot(from_kqid(&init_user_ns, dquot->dq_id),
                  dquot->dq_id.type);

    mutex_lock(&dquot->dq_lock);
    /* Check whether we are not racing with some other dqget() */
    if (atomic_read(&dquot->dq_count) > 1)
        goto out;
    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_id.type));
    if (IS_ERR(handle)) {
        status = PTR_ERR(handle);
        mlog_errno(status);
        goto out_ilock;
    }

    status = ocfs2_global_release_dquot(dquot);
    if (status < 0) {
        mlog_errno(status);
        goto out_trans;
    }
    status = ocfs2_local_release_dquot(handle, dquot);
    /*
     * If we fail here, we cannot do much as global structure is
     * already released. So just complain...
     */
    if (status < 0)
        mlog_errno(status);
    clear_bit(DQ_ACTIVE_B, &dquot->dq_flags);
out_trans:
    ocfs2_commit_trans(osb, handle);
out_ilock:
    ocfs2_unlock_global_qf(oinfo, 1);
out:
    mutex_unlock(&dquot->dq_lock);
    if (status)
        mlog_errno(status);
    return status;
}

/*
 * Read global dquot structure from disk or create it if it does
 * not exist. Also update use count of the global structure and
 * create structure in node-local quota file.
 */
static int ocfs2_acquire_dquot(struct dquot *dquot)
{
    int status = 0, err;
    int ex = 0;
    struct super_block *sb = dquot->dq_sb;
    struct ocfs2_super *osb = OCFS2_SB(sb);
    int type = dquot->dq_id.type;
    struct ocfs2_mem_dqinfo *info = sb_dqinfo(sb, type)->dqi_priv;
    struct inode *gqinode = info->dqi_gqinode;
    int need_alloc = ocfs2_global_qinit_alloc(sb, type);
    handle_t *handle;

    trace_ocfs2_acquire_dquot(from_kqid(&init_user_ns, dquot->dq_id),
                  type);
    mutex_lock(&dquot->dq_lock);
    /*
     * We need an exclusive lock, because we're going to update use count
     * and instantiate possibly new dquot structure
     */
    status = ocfs2_lock_global_qf(info, 1);
    if (status < 0)
        goto out;
    if (!test_bit(DQ_READ_B, &dquot->dq_flags)) {
        status = ocfs2_qinfo_lock(info, 0);
        if (status < 0)
            goto out_dq;
        status = qtree_read_dquot(&info->dqi_gi, dquot);
        ocfs2_qinfo_unlock(info, 0);
        if (status < 0)
            goto out_dq;
    }
    set_bit(DQ_READ_B, &dquot->dq_flags);

    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? */
        ex = 1;
        /*
         * Add blocks to quota file before we start a transaction since
         * locking allocators ranks above a transaction start
         */
        WARN_ON(journal_current_handle());
        status = ocfs2_extend_no_holes(gqinode, NULL,
            gqinode->i_size + (need_alloc << sb->s_blocksize_bits),
            gqinode->i_size);
        if (status < 0)
            goto out_dq;
    }

    handle = ocfs2_start_trans(osb,
                   ocfs2_calc_global_qinit_credits(sb, type));
    if (IS_ERR(handle)) {
        status = PTR_ERR(handle);
        goto out_dq;
    }
    status = ocfs2_qinfo_lock(info, ex);
    if (status < 0)
        goto out_trans;
    status = qtree_write_dquot(&info->dqi_gi, dquot);
    if (ex && info_dirty(sb_dqinfo(sb, type))) {
        err = __ocfs2_global_write_info(sb, type);
        if (!status)
            status = err;
    }
    ocfs2_qinfo_unlock(info, ex);
out_trans:
    ocfs2_commit_trans(osb, handle);
out_dq:
    ocfs2_unlock_global_qf(info, 1);
    if (status < 0)
        goto out;

    status = ocfs2_create_local_dquot(dquot);
    if (status < 0)
        goto out;
    set_bit(DQ_ACTIVE_B, &dquot->dq_flags);
out:
    mutex_unlock(&dquot->dq_lock);
    if (status)
        mlog_errno(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_id.type;
    struct ocfs2_mem_dqinfo *oinfo = sb_dqinfo(sb, type)->dqi_priv;
    handle_t *handle;
    struct ocfs2_super *osb = OCFS2_SB(sb);

    trace_ocfs2_mark_dquot_dirty(from_kqid(&init_user_ns, dquot->dq_id),
                     type);

    /* 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;
    }
    mutex_lock(&sb_dqopt(sb)->dqio_mutex);
    status = ocfs2_sync_dquot(dquot);
    if (status < 0) {
        mlog_errno(status);
        goto out_dlock;
    }
    /* Now write updated local dquot structure */
    status = ocfs2_local_write_dquot(dquot);
out_dlock:
    mutex_unlock(&sb_dqopt(sb)->dqio_mutex);
    ocfs2_commit_trans(osb, handle);
out_ilock:
    ocfs2_unlock_global_qf(oinfo, 1);
out:
    if (status)
        mlog_errno(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;

    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:
    if (status)
        mlog_errno(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);
}

const struct dquot_operations ocfs2_quota_operations = {
    /* We never make dquot dirty so .write_dquot is never called */
    .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,
};