This commit was manufactured by cvs2svn to create branch 'vserver'.
[linux-2.6.git] / fs / gfs2 / quota.c
diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c
new file mode 100644 (file)
index 0000000..c186857
--- /dev/null
@@ -0,0 +1,1227 @@
+/*
+ * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
+ * Copyright (C) 2004-2006 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_file.h"
+#include "ops_address.h"
+#include "util.h"
+
+#define QUOTA_USER 1
+#define QUOTA_GROUP 0
+
+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_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 * (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, 0, &bh_map);
+       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);
+}
+
+/**
+ * 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_SHIFT - 1);
+       unsigned blocksize, iblock, pos;
+       struct buffer_head *bh;
+       struct page *page;
+       void *kaddr;
+       __be64 *ptr;
+       s64 value;
+       int err = -EIO;
+
+       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_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;
+       value = (s64)be64_to_cpu(*ptr) + change;
+       *ptr = cpu_to_be64(value);
+       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);
+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_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++) {
+               qd = qda[x];
+               offset = qd2offset(qd);
+               error = gfs2_adjust_quota(ip, offset, qd->qd_change_sync,
+                                         (struct gfs2_quota_data *)
+                                         qd->qd_gl->gl_lvb);
+               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;
+}
+
+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);
+       }
+}
+