[GFS2] The core of GFS2

This patch contains all the core files for GFS2.

Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 1238 insertions, 0 deletions

diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c
new file mode 100644
index 0000000..a0320f2
--- /dev/null
+++ b/fs/gfs2/quota.c
@@ -0,0 +1,1238 @@
+/*
+ * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
+ * Copyright (C) 2004-2005 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 v.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/tty.h>
+#include <linux/sort.h>
+#include <asm/semaphore.h>
+
+#include "gfs2.h"
+#include "bmap.h"
+#include "glock.h"
+#include "glops.h"
+#include "jdata.h"
+#include "log.h"
+#include "meta_io.h"
+#include "quota.h"
+#include "rgrp.h"
+#include "super.h"
+#include "trans.h"
+
+#define QUOTA_USER 1
+#define QUOTA_GROUP 0
+
+static uint64_t qd2offset(struct gfs2_quota_data *qd)
+{
+	uint64_t offset;
+
+	offset = 2 * (uint64_t)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, uint32_t id,
+		    struct gfs2_quota_data **qdp)
+{
+	struct gfs2_quota_data *qd;
+	int error;
+
+	qd = kzalloc(sizeof(struct gfs2_quota_data), GFP_KERNEL);
+	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 * (uint64_t)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, uint32_t 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 = sdp->sd_qc_inode;
+	unsigned int block, offset;
+	uint64_t dblock;
+	int new = 0;
+	struct buffer_head *bh;
+	int error;
+
+	down(&sdp->sd_quota_mutex);
+
+	if (qd->qd_bh_count++) {
+		up(&sdp->sd_quota_mutex);
+		return 0;
+	}
+
+	block = qd->qd_slot / sdp->sd_qc_per_block;
+	offset = qd->qd_slot % sdp->sd_qc_per_block;;
+
+	error = gfs2_block_map(ip, block, &new, &dblock, NULL);
+	if (error)
+		goto fail;
+	error = gfs2_meta_read(ip->i_gl, dblock, DIO_START | 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));
+
+	up(&sdp->sd_quota_mutex);
+
+	return 0;
+
+ fail_brelse:
+	brelse(bh);
+
+ fail:
+	qd->qd_bh_count--;
+	up(&sdp->sd_quota_mutex);
+	return error;
+}
+
+static void bh_put(struct gfs2_quota_data *qd)
+{
+	struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;
+
+	down(&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;
+	}
+	up(&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, uint32_t 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, uint32_t uid, uint32_t gid)
+{
+	struct gfs2_sbd *sdp = ip->i_sbd;
+	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_di.di_uid, CREATE, qd);
+	if (error)
+		goto out;
+	al->al_qd_num++;
+	qd++;
+
+	error = qdsb_get(sdp, QUOTA_GROUP, ip->i_di.di_gid, CREATE, qd);
+	if (error)
+		goto out;
+	al->al_qd_num++;
+	qd++;
+
+	if (uid != NO_QUOTA_CHANGE && uid != ip->i_di.di_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_di.di_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 = ip->i_sbd;
+	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)
+{
+	struct gfs2_quota_data *qd_a = *(struct gfs2_quota_data **)a;
+	struct gfs2_quota_data *qd_b = *(struct gfs2_quota_data **)b;
+	int ret = 0;
+
+	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))
+			ret = -1;
+		else
+			ret = 1;
+	} else {
+		if (qd_a->qd_id < qd_b->qd_id)
+			ret = -1;
+		else if (qd_a->qd_id > qd_b->qd_id)
+			ret = 1;
+	}
+
+	return ret;
+}
+
+static void do_qc(struct gfs2_quota_data *qd, int64_t change)
+{
+	struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;
+	struct gfs2_inode *ip = sdp->sd_qc_inode;
+	struct gfs2_quota_change *qc = qd->qd_bh_qc;
+	int64_t x;
+
+	down(&sdp->sd_quota_mutex);
+	gfs2_trans_add_bh(ip->i_gl, qd->qd_bh);
+
+	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 = qc->qc_change;
+	x = be64_to_cpu(x) + 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);
+	}
+			
+	up(&sdp->sd_quota_mutex);
+}
+
+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 = 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;
+	uint64_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_ri.ri_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++) {
+		char buf[sizeof(struct gfs2_quota)];
+		struct gfs2_quota q;
+
+		qd = qda[x];
+		offset = qd2offset(qd);
+
+		/* The quota file may not be a multiple of
+		   sizeof(struct gfs2_quota) bytes. */
+		memset(buf, 0, sizeof(struct gfs2_quota));
+
+		error = gfs2_jdata_read_mem(ip, buf, offset,
+					    sizeof(struct gfs2_quota));
+		if (error < 0)
+			goto out_end_trans;
+
+		gfs2_quota_in(&q, buf);
+		q.qu_value += qda[x]->qd_change_sync;
+		gfs2_quota_out(&q, buf);
+
+		error = gfs2_jdata_write_mem(ip, buf, offset,
+					     sizeof(struct gfs2_quota));
+		if (error < 0)
+			goto out_end_trans;
+		else if (error != sizeof(struct gfs2_quota)) {
+			error = -EIO;
+			goto out_end_trans;
+		}
+
+		do_qc(qd, -qd->qd_change_sync);
+
+		memset(&qd->qd_qb, 0, sizeof(struct gfs2_quota_lvb));
+		qd->qd_qb.qb_magic = GFS2_MAGIC;
+		qd->qd_qb.qb_limit = q.qu_limit;
+		qd->qd_qb.qb_warn = q.qu_warn;
+		qd->qd_qb.qb_value = q.qu_value;
+
+		gfs2_quota_lvb_out(&qd->qd_qb, qd->qd_gl->gl_lvb);
+	}
+
+	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_glock(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_holder i_gh;
+	struct gfs2_quota q;
+	char buf[sizeof(struct gfs2_quota)];
+	int error;
+
+ restart:
+	error = gfs2_glock_nq_init(qd->qd_gl, LM_ST_SHARED, 0, q_gh);
+	if (error)
+		return error;
+
+	gfs2_quota_lvb_in(&qd->qd_qb, qd->qd_gl->gl_lvb);
+
+	if (force_refresh || qd->qd_qb.qb_magic != GFS2_MAGIC) {
+		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(sdp->sd_quota_inode->i_gl,
+					  LM_ST_SHARED, 0,
+					  &i_gh);
+		if (error)
+			goto fail;
+
+		memset(buf, 0, sizeof(struct gfs2_quota));
+
+		error = gfs2_jdata_read_mem(sdp->sd_quota_inode, buf,
+					    qd2offset(qd),
+					    sizeof(struct gfs2_quota));
+		if (error < 0)
+			goto fail_gunlock;
+
+		gfs2_glock_dq_uninit(&i_gh);
+
+		gfs2_quota_in(&q, buf);
+
+		memset(&qd->qd_qb, 0, sizeof(struct gfs2_quota_lvb));
+		qd->qd_qb.qb_magic = GFS2_MAGIC;
+		qd->qd_qb.qb_limit = q.qu_limit;
+		qd->qd_qb.qb_warn = q.qu_warn;
+		qd->qd_qb.qb_value = q.qu_value;
+
+		gfs2_quota_lvb_out(&qd->qd_qb, qd->qd_gl->gl_lvb);
+
+		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, uint32_t uid, uint32_t gid)
+{
+	struct gfs2_sbd *sdp = ip->i_sbd;
+	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;
+	int64_t 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 (qd->qd_qb.qb_value >= (int64_t)qd->qd_qb.qb_limit)
+		do_sync = 0;
+	else {
+		value *= gfs2_jindex_size(sdp) * num;
+		do_div(value, den);
+		value += qd->qd_qb.qb_value;
+		if (value < (int64_t)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;
+	char *line;
+	int len;
+
+	line = kmalloc(MAX_LINE, GFP_KERNEL);
+	if (!line)
+		return -ENOMEM;
+
+	len = snprintf(line, MAX_LINE-1, "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);
+	line[MAX_LINE-1] = 0;
+
+	if (current->signal) { /* Is this test still required? */
+		tty_write_message(current->signal->tty, line);
+	}
+
+	kfree(line);
+
+	return 0;
+}
+
+int gfs2_quota_check(struct gfs2_inode *ip, uint32_t uid, uint32_t gid)
+{
+	struct gfs2_sbd *sdp = ip->i_sbd;
+	struct gfs2_alloc *al = &ip->i_alloc;
+	struct gfs2_quota_data *qd;
+	int64_t 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 = qd->qd_qb.qb_value;
+		spin_lock(&sdp->sd_quota_spin);
+		value += qd->qd_change;
+		spin_unlock(&sdp->sd_quota_spin);
+
+		if (qd->qd_qb.qb_limit && (int64_t)qd->qd_qb.qb_limit < value) {
+			print_message(qd, "exceeded");
+			error = -EDQUOT;
+			break;
+		} else if (qd->qd_qb.qb_warn &&
+			   (int64_t)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, int64_t change,
+		       uint32_t uid, uint32_t gid)
+{
+	struct gfs2_alloc *al = &ip->i_alloc;
+	struct gfs2_quota_data *qd;
+	unsigned int x;
+	unsigned int found = 0;
+
+	if (gfs2_assert_warn(ip->i_sbd, 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, uint32_t 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;
+}
+
+int gfs2_quota_read(struct gfs2_sbd *sdp, int user, uint32_t id,
+		    struct gfs2_quota *q)
+{
+	struct gfs2_quota_data *qd;
+	struct gfs2_holder q_gh;
+	int error;
+
+	if (((user) ? (id != current->fsuid) : (!in_group_p(id))) &&
+	    !capable(CAP_SYS_ADMIN))
+		return -EACCES;
+
+	error = qd_get(sdp, user, id, CREATE, &qd);
+	if (error)
+		return error;
+
+	error = do_glock(qd, NO_FORCE, &q_gh);
+	if (error)
+		goto out;
+
+	memset(q, 0, sizeof(struct gfs2_quota));
+	q->qu_limit = qd->qd_qb.qb_limit;
+	q->qu_warn = qd->qd_qb.qb_warn;
+	q->qu_value = qd->qd_qb.qb_value;
+
+	spin_lock(&sdp->sd_quota_spin);
+	q->qu_value += qd->qd_change;
+	spin_unlock(&sdp->sd_quota_spin);
+
+	gfs2_glock_dq_uninit(&q_gh);
+
+ out:
+	qd_put(qd);
+
+	return error;
+}
+
+int gfs2_quota_init(struct gfs2_sbd *sdp)
+{
+	struct gfs2_inode *ip = 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;
+	uint64_t dblock;
+	uint32_t 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_RU(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_block_map(ip, x, &new, &dblock, &extlen);
+			if (error)
+				goto fail;
+		}
+		gfs2_meta_ra(ip->i_gl,  dblock, extlen);
+		error = gfs2_meta_read(ip->i_gl, dblock, DIO_START | DIO_WAIT,
+				       &bh);
+		if (error)
+			goto fail;
+		error = -EIO;
+		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 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);
+	}
+}
+