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root/fs/gfs2/quota.c

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DEFINITIONS

This source file includes following definitions.
  1. qd2offset
  2. qd_alloc
  3. qd_get
  4. qd_hold
  5. qd_put
  6. slot_get
  7. slot_hold
  8. slot_put
  9. bh_get
  10. bh_put
  11. qd_fish
  12. qd_trylock
  13. qd_unlock
  14. qdsb_get
  15. qdsb_put
  16. gfs2_quota_hold
  17. gfs2_quota_unhold
  18. sort_qd
  19. do_qc
  20. gfs2_quota_in
  21. gfs2_quota_out
  22. gfs2_adjust_quota
  23. do_sync
  24. do_glock
  25. gfs2_quota_lock
  26. need_sync
  27. gfs2_quota_unlock
  28. print_message
  29. gfs2_quota_check
  30. gfs2_quota_change
  31. gfs2_quota_sync
  32. gfs2_quota_refresh
  33. gfs2_quota_change_in
  34. gfs2_quota_init
  35. gfs2_quota_scan
  36. gfs2_quota_cleanup

/*
 * 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.
 */

/*
 * Quota change tags are associated with each transaction that allocates or
 * deallocates space.  Those changes are accumulated locally to each node (in a
 * per-node file) and then are periodically synced to the quota file.  This
 * avoids the bottleneck of constantly touching the quota file, but introduces
 * fuzziness in the current usage value of IDs that are being used on different
 * nodes in the cluster simultaneously.  So, it is possible for a user on
 * multiple nodes to overrun their quota, but that overrun is controlable.
 * Since quota tags are part of transactions, there is no need to a quota check
 * program to be run on node crashes or anything like that.
 *
 * There are couple of knobs that let the administrator manage the quota
 * fuzziness.  "quota_quantum" sets the maximum time a quota change can be
 * sitting on one node before being synced to the quota file.  (The default is
 * 60 seconds.)  Another knob, "quota_scale" controls how quickly the frequency
 * of quota file syncs increases as the user moves closer to their limit.  The
 * more frequent the syncs, the more accurate the quota enforcement, but that
 * means that there is more contention between the nodes for the quota file.
 * The default value is one.  This sets the maximum theoretical quota overrun
 * (with infinite node with infinite bandwidth) to twice the user's limit.  (In
 * practice, the maximum overrun you see should be much less.)  A "quota_scale"
 * number greater than one makes quota syncs more frequent and reduces the
 * maximum overrun.  Numbers less than one (but greater than zero) make quota
 * syncs less frequent.
 *
 * GFS quotas also use per-ID Lock Value Blocks (LVBs) to cache the contents of
 * the quota file, so it is not being constantly read.
 */

#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/sort.h>
#include <linux/fs.h>
#include <linux/bio.h>
#include <linux/gfs2_ondisk.h>
#include <linux/lm_interface.h>

#include "gfs2.h"
#include "incore.h"
#include "bmap.h"
#include "glock.h"
#include "glops.h"
#include "log.h"
#include "meta_io.h"
#include "quota.h"
#include "rgrp.h"
#include "super.h"
#include "trans.h"
#include "inode.h"
#include "ops_address.h"
#include "util.h"

#define QUOTA_USER 1
#define QUOTA_GROUP 0

struct gfs2_quota_host {
        u64 qu_limit;
        u64 qu_warn;
        s64 qu_value;
        u32 qu_ll_next;
};

struct gfs2_quota_change_host {
        u64 qc_change;
        u32 qc_flags; /* GFS2_QCF_... */
        u32 qc_id;
};

static u64 qd2offset(struct gfs2_quota_data *qd)
{
        u64 offset;

        offset = 2 * (u64)qd->qd_id + !test_bit(QDF_USER, &qd->qd_flags);
        offset *= sizeof(struct gfs2_quota);

        return offset;
}

static int qd_alloc(struct gfs2_sbd *sdp, int user, u32 id,
                    struct gfs2_quota_data **qdp)
{
        struct gfs2_quota_data *qd;
        int error;

        qd = kzalloc(sizeof(struct gfs2_quota_data), GFP_NOFS);
        if (!qd)
                return -ENOMEM;

        qd->qd_count = 1;
        qd->qd_id = id;
        if (user)
                set_bit(QDF_USER, &qd->qd_flags);
        qd->qd_slot = -1;

        error = gfs2_glock_get(sdp, 2 * (u64)id + !user,
                              &gfs2_quota_glops, CREATE, &qd->qd_gl);
        if (error)
                goto fail;

        error = gfs2_lvb_hold(qd->qd_gl);
        gfs2_glock_put(qd->qd_gl);
        if (error)
                goto fail;

        *qdp = qd;

        return 0;

fail:
        kfree(qd);
        return error;
}

static int qd_get(struct gfs2_sbd *sdp, int user, u32 id, int create,
                  struct gfs2_quota_data **qdp)
{
        struct gfs2_quota_data *qd = NULL, *new_qd = NULL;
        int error, found;

        *qdp = NULL;

        for (;;) {
                found = 0;
                spin_lock(&sdp->sd_quota_spin);
                list_for_each_entry(qd, &sdp->sd_quota_list, qd_list) {
                        if (qd->qd_id == id &&
                            !test_bit(QDF_USER, &qd->qd_flags) == !user) {
                                qd->qd_count++;
                                found = 1;
                                break;
                        }
                }

                if (!found)
                        qd = NULL;

                if (!qd && new_qd) {
                        qd = new_qd;
                        list_add(&qd->qd_list, &sdp->sd_quota_list);
                        atomic_inc(&sdp->sd_quota_count);
                        new_qd = NULL;
                }

                spin_unlock(&sdp->sd_quota_spin);

                if (qd || !create) {
                        if (new_qd) {
                                gfs2_lvb_unhold(new_qd->qd_gl);
                                kfree(new_qd);
                        }
                        *qdp = qd;
                        return 0;
                }

                error = qd_alloc(sdp, user, id, &new_qd);
                if (error)
                        return error;
        }
}

static void qd_hold(struct gfs2_quota_data *qd)
{
        struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;

        spin_lock(&sdp->sd_quota_spin);
        gfs2_assert(sdp, qd->qd_count);
        qd->qd_count++;
        spin_unlock(&sdp->sd_quota_spin);
}

static void qd_put(struct gfs2_quota_data *qd)
{
        struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;
        spin_lock(&sdp->sd_quota_spin);
        gfs2_assert(sdp, qd->qd_count);
        if (!--qd->qd_count)
                qd->qd_last_touched = jiffies;
        spin_unlock(&sdp->sd_quota_spin);
}

static int slot_get(struct gfs2_quota_data *qd)
{
        struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;
        unsigned int c, o = 0, b;
        unsigned char byte = 0;

        spin_lock(&sdp->sd_quota_spin);

        if (qd->qd_slot_count++) {
                spin_unlock(&sdp->sd_quota_spin);
                return 0;
        }

        for (c = 0; c < sdp->sd_quota_chunks; c++)
                for (o = 0; o < PAGE_SIZE; o++) {
                        byte = sdp->sd_quota_bitmap[c][o];
                        if (byte != 0xFF)
                                goto found;
                }

        goto fail;

found:
        for (b = 0; b < 8; b++)
                if (!(byte & (1 << b)))
                        break;
        qd->qd_slot = c * (8 * PAGE_SIZE) + o * 8 + b;

        if (qd->qd_slot >= sdp->sd_quota_slots)
                goto fail;

        sdp->sd_quota_bitmap[c][o] |= 1 << b;

        spin_unlock(&sdp->sd_quota_spin);

        return 0;

fail:
        qd->qd_slot_count--;
        spin_unlock(&sdp->sd_quota_spin);
        return -ENOSPC;
}

static void slot_hold(struct gfs2_quota_data *qd)
{
        struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;

        spin_lock(&sdp->sd_quota_spin);
        gfs2_assert(sdp, qd->qd_slot_count);
        qd->qd_slot_count++;
        spin_unlock(&sdp->sd_quota_spin);
}

static void slot_put(struct gfs2_quota_data *qd)
{
        struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;

        spin_lock(&sdp->sd_quota_spin);
        gfs2_assert(sdp, qd->qd_slot_count);
        if (!--qd->qd_slot_count) {
                gfs2_icbit_munge(sdp, sdp->sd_quota_bitmap, qd->qd_slot, 0);
                qd->qd_slot = -1;
        }
        spin_unlock(&sdp->sd_quota_spin);
}

static int bh_get(struct gfs2_quota_data *qd)
{
        struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;
        struct gfs2_inode *ip = GFS2_I(sdp->sd_qc_inode);
        unsigned int block, offset;
        struct buffer_head *bh;
        int error;
        struct buffer_head bh_map = { .b_state = 0, .b_blocknr = 0 };

        mutex_lock(&sdp->sd_quota_mutex);

        if (qd->qd_bh_count++) {
                mutex_unlock(&sdp->sd_quota_mutex);
                return 0;
        }

        block = qd->qd_slot / sdp->sd_qc_per_block;
        offset = qd->qd_slot % sdp->sd_qc_per_block;

        bh_map.b_size = 1 << ip->i_inode.i_blkbits;
        error = gfs2_block_map(&ip->i_inode, block, &bh_map, 0);
        if (error)
                goto fail;
        error = gfs2_meta_read(ip->i_gl, bh_map.b_blocknr, DIO_WAIT, &bh);
        if (error)
                goto fail;
        error = -EIO;
        if (gfs2_metatype_check(sdp, bh, GFS2_METATYPE_QC))
                goto fail_brelse;

        qd->qd_bh = bh;
        qd->qd_bh_qc = (struct gfs2_quota_change *)
                (bh->b_data + sizeof(struct gfs2_meta_header) +
                 offset * sizeof(struct gfs2_quota_change));

        mutex_unlock(&sdp->sd_quota_mutex);

        return 0;

fail_brelse:
        brelse(bh);
fail:
        qd->qd_bh_count--;
        mutex_unlock(&sdp->sd_quota_mutex);
        return error;
}

static void bh_put(struct gfs2_quota_data *qd)
{
        struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;

        mutex_lock(&sdp->sd_quota_mutex);
        gfs2_assert(sdp, qd->qd_bh_count);
        if (!--qd->qd_bh_count) {
                brelse(qd->qd_bh);
                qd->qd_bh = NULL;
                qd->qd_bh_qc = NULL;
        }
        mutex_unlock(&sdp->sd_quota_mutex);
}

static int qd_fish(struct gfs2_sbd *sdp, struct gfs2_quota_data **qdp)
{
        struct gfs2_quota_data *qd = NULL;
        int error;
        int found = 0;

        *qdp = NULL;

        if (sdp->sd_vfs->s_flags & MS_RDONLY)
                return 0;

        spin_lock(&sdp->sd_quota_spin);

        list_for_each_entry(qd, &sdp->sd_quota_list, qd_list) {
                if (test_bit(QDF_LOCKED, &qd->qd_flags) ||
                    !test_bit(QDF_CHANGE, &qd->qd_flags) ||
                    qd->qd_sync_gen >= sdp->sd_quota_sync_gen)
                        continue;

                list_move_tail(&qd->qd_list, &sdp->sd_quota_list);

                set_bit(QDF_LOCKED, &qd->qd_flags);
                gfs2_assert_warn(sdp, qd->qd_count);
                qd->qd_count++;
                qd->qd_change_sync = qd->qd_change;
                gfs2_assert_warn(sdp, qd->qd_slot_count);
                qd->qd_slot_count++;
                found = 1;

                break;
        }

        if (!found)
                qd = NULL;

        spin_unlock(&sdp->sd_quota_spin);

        if (qd) {
                gfs2_assert_warn(sdp, qd->qd_change_sync);
                error = bh_get(qd);
                if (error) {
                        clear_bit(QDF_LOCKED, &qd->qd_flags);
                        slot_put(qd);
                        qd_put(qd);
                        return error;
                }
        }

        *qdp = qd;

        return 0;
}

static int qd_trylock(struct gfs2_quota_data *qd)
{
        struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;

        if (sdp->sd_vfs->s_flags & MS_RDONLY)
                return 0;

        spin_lock(&sdp->sd_quota_spin);

        if (test_bit(QDF_LOCKED, &qd->qd_flags) ||
            !test_bit(QDF_CHANGE, &qd->qd_flags)) {
                spin_unlock(&sdp->sd_quota_spin);
                return 0;
        }

        list_move_tail(&qd->qd_list, &sdp->sd_quota_list);

        set_bit(QDF_LOCKED, &qd->qd_flags);
        gfs2_assert_warn(sdp, qd->qd_count);
        qd->qd_count++;
        qd->qd_change_sync = qd->qd_change;
        gfs2_assert_warn(sdp, qd->qd_slot_count);
        qd->qd_slot_count++;

        spin_unlock(&sdp->sd_quota_spin);

        gfs2_assert_warn(sdp, qd->qd_change_sync);
        if (bh_get(qd)) {
                clear_bit(QDF_LOCKED, &qd->qd_flags);
                slot_put(qd);
                qd_put(qd);
                return 0;
        }

        return 1;
}

static void qd_unlock(struct gfs2_quota_data *qd)
{
        gfs2_assert_warn(qd->qd_gl->gl_sbd,
                         test_bit(QDF_LOCKED, &qd->qd_flags));
        clear_bit(QDF_LOCKED, &qd->qd_flags);
        bh_put(qd);
        slot_put(qd);
        qd_put(qd);
}

static int qdsb_get(struct gfs2_sbd *sdp, int user, u32 id, int create,
                    struct gfs2_quota_data **qdp)
{
        int error;

        error = qd_get(sdp, user, id, create, qdp);
        if (error)
                return error;

        error = slot_get(*qdp);
        if (error)
                goto fail;

        error = bh_get(*qdp);
        if (error)
                goto fail_slot;

        return 0;

fail_slot:
        slot_put(*qdp);
fail:
        qd_put(*qdp);
        return error;
}

static void qdsb_put(struct gfs2_quota_data *qd)
{
        bh_put(qd);
        slot_put(qd);
        qd_put(qd);
}

int gfs2_quota_hold(struct gfs2_inode *ip, u32 uid, u32 gid)
{
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct gfs2_alloc *al = ip->i_alloc;
        struct gfs2_quota_data **qd = al->al_qd;
        int error;

        if (gfs2_assert_warn(sdp, !al->al_qd_num) ||
            gfs2_assert_warn(sdp, !test_bit(GIF_QD_LOCKED, &ip->i_flags)))
                return -EIO;

        if (sdp->sd_args.ar_quota == GFS2_QUOTA_OFF)
                return 0;

        error = qdsb_get(sdp, QUOTA_USER, ip->i_inode.i_uid, CREATE, qd);
        if (error)
                goto out;
        al->al_qd_num++;
        qd++;

        error = qdsb_get(sdp, QUOTA_GROUP, ip->i_inode.i_gid, CREATE, qd);
        if (error)
                goto out;
        al->al_qd_num++;
        qd++;

        if (uid != NO_QUOTA_CHANGE && uid != ip->i_inode.i_uid) {
                error = qdsb_get(sdp, QUOTA_USER, uid, CREATE, qd);
                if (error)
                        goto out;
                al->al_qd_num++;
                qd++;
        }

        if (gid != NO_QUOTA_CHANGE && gid != ip->i_inode.i_gid) {
                error = qdsb_get(sdp, QUOTA_GROUP, gid, CREATE, qd);
                if (error)
                        goto out;
                al->al_qd_num++;
                qd++;
        }

out:
        if (error)
                gfs2_quota_unhold(ip);
        return error;
}

void gfs2_quota_unhold(struct gfs2_inode *ip)
{
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct gfs2_alloc *al = ip->i_alloc;
        unsigned int x;

        gfs2_assert_warn(sdp, !test_bit(GIF_QD_LOCKED, &ip->i_flags));

        for (x = 0; x < al->al_qd_num; x++) {
                qdsb_put(al->al_qd[x]);
                al->al_qd[x] = NULL;
        }
        al->al_qd_num = 0;
}

static int sort_qd(const void *a, const void *b)
{
        const struct gfs2_quota_data *qd_a = *(const struct gfs2_quota_data **)a;
        const struct gfs2_quota_data *qd_b = *(const struct gfs2_quota_data **)b;

        if (!test_bit(QDF_USER, &qd_a->qd_flags) !=
            !test_bit(QDF_USER, &qd_b->qd_flags)) {
                if (test_bit(QDF_USER, &qd_a->qd_flags))
                        return -1;
                else
                        return 1;
        }
        if (qd_a->qd_id < qd_b->qd_id)
                return -1;
        if (qd_a->qd_id > qd_b->qd_id)
                return 1;

        return 0;
}

static void do_qc(struct gfs2_quota_data *qd, s64 change)
{
        struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;
        struct gfs2_inode *ip = GFS2_I(sdp->sd_qc_inode);
        struct gfs2_quota_change *qc = qd->qd_bh_qc;
        s64 x;

        mutex_lock(&sdp->sd_quota_mutex);
        gfs2_trans_add_bh(ip->i_gl, qd->qd_bh, 1);

        if (!test_bit(QDF_CHANGE, &qd->qd_flags)) {
                qc->qc_change = 0;
                qc->qc_flags = 0;
                if (test_bit(QDF_USER, &qd->qd_flags))
                        qc->qc_flags = cpu_to_be32(GFS2_QCF_USER);
                qc->qc_id = cpu_to_be32(qd->qd_id);
        }

        x = be64_to_cpu(qc->qc_change) + change;
        qc->qc_change = cpu_to_be64(x);

        spin_lock(&sdp->sd_quota_spin);
        qd->qd_change = x;
        spin_unlock(&sdp->sd_quota_spin);

        if (!x) {
                gfs2_assert_warn(sdp, test_bit(QDF_CHANGE, &qd->qd_flags));
                clear_bit(QDF_CHANGE, &qd->qd_flags);
                qc->qc_flags = 0;
                qc->qc_id = 0;
                slot_put(qd);
                qd_put(qd);
        } else if (!test_and_set_bit(QDF_CHANGE, &qd->qd_flags)) {
                qd_hold(qd);
                slot_hold(qd);
        }

        mutex_unlock(&sdp->sd_quota_mutex);
}

static void gfs2_quota_in(struct gfs2_quota_host *qu, const void *buf)
{
        const struct gfs2_quota *str = buf;

        qu->qu_limit = be64_to_cpu(str->qu_limit);
        qu->qu_warn = be64_to_cpu(str->qu_warn);
        qu->qu_value = be64_to_cpu(str->qu_value);
        qu->qu_ll_next = be32_to_cpu(str->qu_ll_next);
}

static void gfs2_quota_out(const struct gfs2_quota_host *qu, void *buf)
{
        struct gfs2_quota *str = buf;

        str->qu_limit = cpu_to_be64(qu->qu_limit);
        str->qu_warn = cpu_to_be64(qu->qu_warn);
        str->qu_value = cpu_to_be64(qu->qu_value);
        str->qu_ll_next = cpu_to_be32(qu->qu_ll_next);
        memset(&str->qu_reserved, 0, sizeof(str->qu_reserved));
}

/**
 * gfs2_adjust_quota
 *
 * This function was mostly borrowed from gfs2_block_truncate_page which was
 * in turn mostly borrowed from ext3
 */
static int gfs2_adjust_quota(struct gfs2_inode *ip, loff_t loc,
                             s64 change, struct gfs2_quota_data *qd)
{
        struct inode *inode = &ip->i_inode;
        struct address_space *mapping = inode->i_mapping;
        unsigned long index = loc >> PAGE_CACHE_SHIFT;
        unsigned offset = loc & (PAGE_CACHE_SIZE - 1);
        unsigned blocksize, iblock, pos;
        struct buffer_head *bh;
        struct page *page;
        void *kaddr;
        char *ptr;
        struct gfs2_quota_host qp;
        s64 value;
        int err = -EIO;

        if (gfs2_is_stuffed(ip))
                gfs2_unstuff_dinode(ip, NULL);
        
        page = grab_cache_page(mapping, index);
        if (!page)
                return -ENOMEM;

        blocksize = inode->i_sb->s_blocksize;
        iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);

        if (!page_has_buffers(page))
                create_empty_buffers(page, blocksize, 0);

        bh = page_buffers(page);
        pos = blocksize;
        while (offset >= pos) {
                bh = bh->b_this_page;
                iblock++;
                pos += blocksize;
        }

        if (!buffer_mapped(bh)) {
                gfs2_block_map(inode, iblock, bh, 1);
                if (!buffer_mapped(bh))
                        goto unlock;
        }

        if (PageUptodate(page))
                set_buffer_uptodate(bh);

        if (!buffer_uptodate(bh)) {
                ll_rw_block(READ_META, 1, &bh);
                wait_on_buffer(bh);
                if (!buffer_uptodate(bh))
                        goto unlock;
        }

        gfs2_trans_add_bh(ip->i_gl, bh, 0);

        kaddr = kmap_atomic(page, KM_USER0);
        ptr = kaddr + offset;
        gfs2_quota_in(&qp, ptr);
        qp.qu_value += change;
        value = qp.qu_value;
        gfs2_quota_out(&qp, ptr);
        flush_dcache_page(page);
        kunmap_atomic(kaddr, KM_USER0);
        err = 0;
        qd->qd_qb.qb_magic = cpu_to_be32(GFS2_MAGIC);
        qd->qd_qb.qb_value = cpu_to_be64(value);
        ((struct gfs2_quota_lvb*)(qd->qd_gl->gl_lvb))->qb_magic = cpu_to_be32(GFS2_MAGIC);
        ((struct gfs2_quota_lvb*)(qd->qd_gl->gl_lvb))->qb_value = cpu_to_be64(value);
unlock:
        unlock_page(page);
        page_cache_release(page);
        return err;
}

static int do_sync(unsigned int num_qd, struct gfs2_quota_data **qda)
{
        struct gfs2_sbd *sdp = (*qda)->qd_gl->gl_sbd;
        struct gfs2_inode *ip = GFS2_I(sdp->sd_quota_inode);
        unsigned int data_blocks, ind_blocks;
        struct gfs2_holder *ghs, i_gh;
        unsigned int qx, x;
        struct gfs2_quota_data *qd;
        loff_t offset;
        unsigned int nalloc = 0, blocks;
        struct gfs2_alloc *al = NULL;
        int error;

        gfs2_write_calc_reserv(ip, sizeof(struct gfs2_quota),
                              &data_blocks, &ind_blocks);

        ghs = kcalloc(num_qd, sizeof(struct gfs2_holder), GFP_NOFS);
        if (!ghs)
                return -ENOMEM;

        sort(qda, num_qd, sizeof(struct gfs2_quota_data *), sort_qd, NULL);
        for (qx = 0; qx < num_qd; qx++) {
                error = gfs2_glock_nq_init(qda[qx]->qd_gl,
                                           LM_ST_EXCLUSIVE,
                                           GL_NOCACHE, &ghs[qx]);
                if (error)
                        goto out;
        }

        error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &i_gh);
        if (error)
                goto out;

        for (x = 0; x < num_qd; x++) {
                int alloc_required;

                offset = qd2offset(qda[x]);
                error = gfs2_write_alloc_required(ip, offset,
                                                  sizeof(struct gfs2_quota),
                                                  &alloc_required);
                if (error)
                        goto out_gunlock;
                if (alloc_required)
                        nalloc++;
        }

        al = gfs2_alloc_get(ip);
        if (!al) {
                error = -ENOMEM;
                goto out_gunlock;
        }
        /* 
         * 1 blk for unstuffing inode if stuffed. We add this extra
         * block to the reservation unconditionally. If the inode
         * doesn't need unstuffing, the block will be released to the 
         * rgrp since it won't be allocated during the transaction
         */
        al->al_requested = 1;
        /* +1 in the end for block requested above for unstuffing */
        blocks = num_qd * data_blocks + RES_DINODE + num_qd + 1;

        if (nalloc)
                al->al_requested += nalloc * (data_blocks + ind_blocks);                
        error = gfs2_inplace_reserve(ip);
        if (error)
                goto out_alloc;

        if (nalloc)
                blocks += al->al_rgd->rd_length + nalloc * ind_blocks + RES_STATFS;

        error = gfs2_trans_begin(sdp, blocks, 0);
        if (error)
                goto out_ipres;

        for (x = 0; x < num_qd; x++) {
                qd = qda[x];
                offset = qd2offset(qd);
                error = gfs2_adjust_quota(ip, offset, qd->qd_change_sync,
                                          (struct gfs2_quota_data *)
                                          qd);
                if (error)
                        goto out_end_trans;

                do_qc(qd, -qd->qd_change_sync);
        }

        error = 0;

out_end_trans:
        gfs2_trans_end(sdp);
out_ipres:
        gfs2_inplace_release(ip);
out_alloc:
        gfs2_alloc_put(ip);
out_gunlock:
        gfs2_glock_dq_uninit(&i_gh);
out:
        while (qx--)
                gfs2_glock_dq_uninit(&ghs[qx]);
        kfree(ghs);
        gfs2_log_flush(ip->i_gl->gl_sbd, ip->i_gl);
        return error;
}

static int do_glock(struct gfs2_quota_data *qd, int force_refresh,
                    struct gfs2_holder *q_gh)
{
        struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;
        struct gfs2_inode *ip = GFS2_I(sdp->sd_quota_inode);
        struct gfs2_holder i_gh;
        struct gfs2_quota_host q;
        char buf[sizeof(struct gfs2_quota)];
        int error;
        struct gfs2_quota_lvb *qlvb;

restart:
        error = gfs2_glock_nq_init(qd->qd_gl, LM_ST_SHARED, 0, q_gh);
        if (error)
                return error;

        qd->qd_qb = *(struct gfs2_quota_lvb *)qd->qd_gl->gl_lvb;

        if (force_refresh || qd->qd_qb.qb_magic != cpu_to_be32(GFS2_MAGIC)) {
                loff_t pos;
                gfs2_glock_dq_uninit(q_gh);
                error = gfs2_glock_nq_init(qd->qd_gl,
                                          LM_ST_EXCLUSIVE, GL_NOCACHE,
                                          q_gh);
                if (error)
                        return error;

                error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &i_gh);
                if (error)
                        goto fail;

                memset(buf, 0, sizeof(struct gfs2_quota));
                pos = qd2offset(qd);
                error = gfs2_internal_read(ip, NULL, buf, &pos,
                                           sizeof(struct gfs2_quota));
                if (error < 0)
                        goto fail_gunlock;

                gfs2_glock_dq_uninit(&i_gh);


                gfs2_quota_in(&q, buf);
                qlvb = (struct gfs2_quota_lvb *)qd->qd_gl->gl_lvb;
                qlvb->qb_magic = cpu_to_be32(GFS2_MAGIC);
                qlvb->__pad = 0;
                qlvb->qb_limit = cpu_to_be64(q.qu_limit);
                qlvb->qb_warn = cpu_to_be64(q.qu_warn);
                qlvb->qb_value = cpu_to_be64(q.qu_value);
                qd->qd_qb = *qlvb;

                if (gfs2_glock_is_blocking(qd->qd_gl)) {
                        gfs2_glock_dq_uninit(q_gh);
                        force_refresh = 0;
                        goto restart;
                }
        }

        return 0;

fail_gunlock:
        gfs2_glock_dq_uninit(&i_gh);
fail:
        gfs2_glock_dq_uninit(q_gh);
        return error;
}

int gfs2_quota_lock(struct gfs2_inode *ip, u32 uid, u32 gid)
{
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct gfs2_alloc *al = ip->i_alloc;
        unsigned int x;
        int error = 0;

        gfs2_quota_hold(ip, uid, gid);

        if (capable(CAP_SYS_RESOURCE) ||
            sdp->sd_args.ar_quota != GFS2_QUOTA_ON)
                return 0;

        sort(al->al_qd, al->al_qd_num, sizeof(struct gfs2_quota_data *),
             sort_qd, NULL);

        for (x = 0; x < al->al_qd_num; x++) {
                error = do_glock(al->al_qd[x], NO_FORCE, &al->al_qd_ghs[x]);
                if (error)
                        break;
        }

        if (!error)
                set_bit(GIF_QD_LOCKED, &ip->i_flags);
        else {
                while (x--)
                        gfs2_glock_dq_uninit(&al->al_qd_ghs[x]);
                gfs2_quota_unhold(ip);
        }

        return error;
}

static int need_sync(struct gfs2_quota_data *qd)
{
        struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;
        struct gfs2_tune *gt = &sdp->sd_tune;
        s64 value;
        unsigned int num, den;
        int do_sync = 1;

        if (!qd->qd_qb.qb_limit)
                return 0;

        spin_lock(&sdp->sd_quota_spin);
        value = qd->qd_change;
        spin_unlock(&sdp->sd_quota_spin);

        spin_lock(&gt->gt_spin);
        num = gt->gt_quota_scale_num;
        den = gt->gt_quota_scale_den;
        spin_unlock(&gt->gt_spin);

        if (value < 0)
                do_sync = 0;
        else if ((s64)be64_to_cpu(qd->qd_qb.qb_value) >=
                 (s64)be64_to_cpu(qd->qd_qb.qb_limit))
                do_sync = 0;
        else {
                value *= gfs2_jindex_size(sdp) * num;
                value = div_s64(value, den);
                value += (s64)be64_to_cpu(qd->qd_qb.qb_value);
                if (value < (s64)be64_to_cpu(qd->qd_qb.qb_limit))
                        do_sync = 0;
        }

        return do_sync;
}

void gfs2_quota_unlock(struct gfs2_inode *ip)
{
        struct gfs2_alloc *al = ip->i_alloc;
        struct gfs2_quota_data *qda[4];
        unsigned int count = 0;
        unsigned int x;

        if (!test_and_clear_bit(GIF_QD_LOCKED, &ip->i_flags))
                goto out;

        for (x = 0; x < al->al_qd_num; x++) {
                struct gfs2_quota_data *qd;
                int sync;

                qd = al->al_qd[x];
                sync = need_sync(qd);

                gfs2_glock_dq_uninit(&al->al_qd_ghs[x]);

                if (sync && qd_trylock(qd))
                        qda[count++] = qd;
        }

        if (count) {
                do_sync(count, qda);
                for (x = 0; x < count; x++)
                        qd_unlock(qda[x]);
        }

out:
        gfs2_quota_unhold(ip);
}

#define MAX_LINE 256

static int print_message(struct gfs2_quota_data *qd, char *type)
{
        struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;

        printk(KERN_INFO "GFS2: fsid=%s: quota %s for %s %u\r\n",
               sdp->sd_fsname, type,
               (test_bit(QDF_USER, &qd->qd_flags)) ? "user" : "group",
               qd->qd_id);

        return 0;
}

int gfs2_quota_check(struct gfs2_inode *ip, u32 uid, u32 gid)
{
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct gfs2_alloc *al = ip->i_alloc;
        struct gfs2_quota_data *qd;
        s64 value;
        unsigned int x;
        int error = 0;

        if (!test_bit(GIF_QD_LOCKED, &ip->i_flags))
                return 0;

        if (sdp->sd_args.ar_quota != GFS2_QUOTA_ON)
                return 0;

        for (x = 0; x < al->al_qd_num; x++) {
                qd = al->al_qd[x];

                if (!((qd->qd_id == uid && test_bit(QDF_USER, &qd->qd_flags)) ||
                      (qd->qd_id == gid && !test_bit(QDF_USER, &qd->qd_flags))))
                        continue;

                value = (s64)be64_to_cpu(qd->qd_qb.qb_value);
                spin_lock(&sdp->sd_quota_spin);
                value += qd->qd_change;
                spin_unlock(&sdp->sd_quota_spin);

                if (be64_to_cpu(qd->qd_qb.qb_limit) && (s64)be64_to_cpu(qd->qd_qb.qb_limit) < value) {
                        print_message(qd, "exceeded");
                        error = -EDQUOT;
                        break;
                } else if (be64_to_cpu(qd->qd_qb.qb_warn) &&
                           (s64)be64_to_cpu(qd->qd_qb.qb_warn) < value &&
                           time_after_eq(jiffies, qd->qd_last_warn +
                                         gfs2_tune_get(sdp,
                                                gt_quota_warn_period) * HZ)) {
                        error = print_message(qd, "warning");
                        qd->qd_last_warn = jiffies;
                }
        }

        return error;
}

void gfs2_quota_change(struct gfs2_inode *ip, s64 change,
                       u32 uid, u32 gid)
{
        struct gfs2_alloc *al = ip->i_alloc;
        struct gfs2_quota_data *qd;
        unsigned int x;

        if (gfs2_assert_warn(GFS2_SB(&ip->i_inode), change))
                return;
        if (ip->i_di.di_flags & GFS2_DIF_SYSTEM)
                return;

        for (x = 0; x < al->al_qd_num; x++) {
                qd = al->al_qd[x];

                if ((qd->qd_id == uid && test_bit(QDF_USER, &qd->qd_flags)) ||
                    (qd->qd_id == gid && !test_bit(QDF_USER, &qd->qd_flags))) {
                        do_qc(qd, change);
                }
        }
}

int gfs2_quota_sync(struct gfs2_sbd *sdp)
{
        struct gfs2_quota_data **qda;
        unsigned int max_qd = gfs2_tune_get(sdp, gt_quota_simul_sync);
        unsigned int num_qd;
        unsigned int x;
        int error = 0;

        sdp->sd_quota_sync_gen++;

        qda = kcalloc(max_qd, sizeof(struct gfs2_quota_data *), GFP_KERNEL);
        if (!qda)
                return -ENOMEM;

        do {
                num_qd = 0;

                for (;;) {
                        error = qd_fish(sdp, qda + num_qd);
                        if (error || !qda[num_qd])
                                break;
                        if (++num_qd == max_qd)
                                break;
                }

                if (num_qd) {
                        if (!error)
                                error = do_sync(num_qd, qda);
                        if (!error)
                                for (x = 0; x < num_qd; x++)
                                        qda[x]->qd_sync_gen =
                                                sdp->sd_quota_sync_gen;

                        for (x = 0; x < num_qd; x++)
                                qd_unlock(qda[x]);
                }
        } while (!error && num_qd == max_qd);

        kfree(qda);

        return error;
}

int gfs2_quota_refresh(struct gfs2_sbd *sdp, int user, u32 id)
{
        struct gfs2_quota_data *qd;
        struct gfs2_holder q_gh;
        int error;

        error = qd_get(sdp, user, id, CREATE, &qd);
        if (error)
                return error;

        error = do_glock(qd, FORCE, &q_gh);
        if (!error)
                gfs2_glock_dq_uninit(&q_gh);

        qd_put(qd);

        return error;
}

static void gfs2_quota_change_in(struct gfs2_quota_change_host *qc, const void *buf)
{
        const struct gfs2_quota_change *str = buf;

        qc->qc_change = be64_to_cpu(str->qc_change);
        qc->qc_flags = be32_to_cpu(str->qc_flags);
        qc->qc_id = be32_to_cpu(str->qc_id);
}

int gfs2_quota_init(struct gfs2_sbd *sdp)
{
        struct gfs2_inode *ip = GFS2_I(sdp->sd_qc_inode);
        unsigned int blocks = ip->i_di.di_size >> sdp->sd_sb.sb_bsize_shift;
        unsigned int x, slot = 0;
        unsigned int found = 0;
        u64 dblock;
        u32 extlen = 0;
        int error;

        if (!ip->i_di.di_size || ip->i_di.di_size > (64 << 20) ||
            ip->i_di.di_size & (sdp->sd_sb.sb_bsize - 1)) {
                gfs2_consist_inode(ip);
                return -EIO;
        }
        sdp->sd_quota_slots = blocks * sdp->sd_qc_per_block;
        sdp->sd_quota_chunks = DIV_ROUND_UP(sdp->sd_quota_slots, 8 * PAGE_SIZE);

        error = -ENOMEM;

        sdp->sd_quota_bitmap = kcalloc(sdp->sd_quota_chunks,
                                       sizeof(unsigned char *), GFP_NOFS);
        if (!sdp->sd_quota_bitmap)
                return error;

        for (x = 0; x < sdp->sd_quota_chunks; x++) {
                sdp->sd_quota_bitmap[x] = kzalloc(PAGE_SIZE, GFP_NOFS);
                if (!sdp->sd_quota_bitmap[x])
                        goto fail;
        }

        for (x = 0; x < blocks; x++) {
                struct buffer_head *bh;
                unsigned int y;

                if (!extlen) {
                        int new = 0;
                        error = gfs2_extent_map(&ip->i_inode, x, &new, &dblock, &extlen);
                        if (error)
                                goto fail;
                }
                error = -EIO;
                bh = gfs2_meta_ra(ip->i_gl, dblock, extlen);
                if (!bh)
                        goto fail;
                if (gfs2_metatype_check(sdp, bh, GFS2_METATYPE_QC)) {
                        brelse(bh);
                        goto fail;
                }

                for (y = 0; y < sdp->sd_qc_per_block && slot < sdp->sd_quota_slots;
                     y++, slot++) {
                        struct gfs2_quota_change_host qc;
                        struct gfs2_quota_data *qd;

                        gfs2_quota_change_in(&qc, bh->b_data +
                                          sizeof(struct gfs2_meta_header) +
                                          y * sizeof(struct gfs2_quota_change));
                        if (!qc.qc_change)
                                continue;

                        error = qd_alloc(sdp, (qc.qc_flags & GFS2_QCF_USER),
                                         qc.qc_id, &qd);
                        if (error) {
                                brelse(bh);
                                goto fail;
                        }

                        set_bit(QDF_CHANGE, &qd->qd_flags);
                        qd->qd_change = qc.qc_change;
                        qd->qd_slot = slot;
                        qd->qd_slot_count = 1;
                        qd->qd_last_touched = jiffies;

                        spin_lock(&sdp->sd_quota_spin);
                        gfs2_icbit_munge(sdp, sdp->sd_quota_bitmap, slot, 1);
                        list_add(&qd->qd_list, &sdp->sd_quota_list);
                        atomic_inc(&sdp->sd_quota_count);
                        spin_unlock(&sdp->sd_quota_spin);

                        found++;
                }

                brelse(bh);
                dblock++;
                extlen--;
        }

        if (found)
                fs_info(sdp, "found %u quota changes\n", found);

        return 0;

fail:
        gfs2_quota_cleanup(sdp);
        return error;
}

void gfs2_quota_scan(struct gfs2_sbd *sdp)
{
        struct gfs2_quota_data *qd, *safe;
        LIST_HEAD(dead);

        spin_lock(&sdp->sd_quota_spin);
        list_for_each_entry_safe(qd, safe, &sdp->sd_quota_list, qd_list) {
                if (!qd->qd_count &&
                    time_after_eq(jiffies, qd->qd_last_touched +
                                gfs2_tune_get(sdp, gt_quota_cache_secs) * HZ)) {
                        list_move(&qd->qd_list, &dead);
                        gfs2_assert_warn(sdp,
                                         atomic_read(&sdp->sd_quota_count) > 0);
                        atomic_dec(&sdp->sd_quota_count);
                }
        }
        spin_unlock(&sdp->sd_quota_spin);

        while (!list_empty(&dead)) {
                qd = list_entry(dead.next, struct gfs2_quota_data, qd_list);
                list_del(&qd->qd_list);

                gfs2_assert_warn(sdp, !qd->qd_change);
                gfs2_assert_warn(sdp, !qd->qd_slot_count);
                gfs2_assert_warn(sdp, !qd->qd_bh_count);

                gfs2_lvb_unhold(qd->qd_gl);
                kfree(qd);
        }
}

void gfs2_quota_cleanup(struct gfs2_sbd *sdp)
{
        struct list_head *head = &sdp->sd_quota_list;
        struct gfs2_quota_data *qd;
        unsigned int x;

        spin_lock(&sdp->sd_quota_spin);
        while (!list_empty(head)) {
                qd = list_entry(head->prev, struct gfs2_quota_data, qd_list);

                if (qd->qd_count > 1 ||
                    (qd->qd_count && !test_bit(QDF_CHANGE, &qd->qd_flags))) {
                        list_move(&qd->qd_list, head);
                        spin_unlock(&sdp->sd_quota_spin);
                        schedule();
                        spin_lock(&sdp->sd_quota_spin);
                        continue;
                }

                list_del(&qd->qd_list);
                atomic_dec(&sdp->sd_quota_count);
                spin_unlock(&sdp->sd_quota_spin);

                if (!qd->qd_count) {
                        gfs2_assert_warn(sdp, !qd->qd_change);
                        gfs2_assert_warn(sdp, !qd->qd_slot_count);
                } else
                        gfs2_assert_warn(sdp, qd->qd_slot_count == 1);
                gfs2_assert_warn(sdp, !qd->qd_bh_count);

                gfs2_lvb_unhold(qd->qd_gl);
                kfree(qd);

                spin_lock(&sdp->sd_quota_spin);
        }
        spin_unlock(&sdp->sd_quota_spin);

        gfs2_assert_warn(sdp, !atomic_read(&sdp->sd_quota_count));

        if (sdp->sd_quota_bitmap) {
                for (x = 0; x < sdp->sd_quota_chunks; x++)
                        kfree(sdp->sd_quota_bitmap[x]);
                kfree(sdp->sd_quota_bitmap);
        }
}


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