quota.c

linux 内核源代码

		iblock++;
		pos += blocksize;
	}

	if (!buffer_mapped(bh)) {
		gfs2_get_block(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;
	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_KERNEL);
	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++;
	}

	if (nalloc) {
		al = gfs2_alloc_get(ip);

		al->al_requested = nalloc * (data_blocks + ind_blocks);

		error = gfs2_inplace_reserve(ip);
		if (error)
			goto out_alloc;

		error = gfs2_trans_begin(sdp,
					 al->al_rgd->rd_length +
					 num_qd * data_blocks +
					 nalloc * ind_blocks +
					 RES_DINODE + num_qd +
					 RES_STATFS, 0);
		if (error)
			goto out_ipres;
	} else {
		error = gfs2_trans_begin(sdp,
					 num_qd * data_blocks +
					 RES_DINODE + num_qd, 0);
		if (error)
			goto out_gunlock;
	}

	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:
	if (nalloc)
		gfs2_inplace_release(ip);
out_alloc:
	if (nalloc)
		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)];
	struct file_ra_state ra_state;
	int error;
	struct gfs2_quota_lvb *qlvb;

	file_ra_state_init(&ra_state, sdp->sd_quota_inode->i_mapping);
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, &ra_state, 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;
		do_div(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;
	unsigned int found = 0;

	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);
			found++;
		}
	}
}

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_KERNEL);
	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_KERNEL);
		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);
	}
}