quota: Reduce contention on dq_data_lock
authorJan Kara <jack@suse.cz>
Mon, 7 Aug 2017 11:19:50 +0000 (13:19 +0200)
committerJan Kara <jack@suse.cz>
Thu, 17 Aug 2017 20:07:59 +0000 (22:07 +0200)
dq_data_lock is currently used to protect all modifications of quota
accounting information, consistency of quota accounting on the inode,
and dquot pointers from inode. As a result contention on the lock can be
pretty heavy.

Reduce the contention on the lock by protecting quota accounting
information by a new dquot->dq_dqb_lock and consistency of quota
accounting with inode usage by inode->i_lock.

This change reduces time to create 500000 files on ext4 on ramdisk by 50
different processes in separate directories by 6% when user quota is
turned on. When those 50 processes belong to 50 different users, the
improvement is about 9%.

Signed-off-by: Jan Kara <jack@suse.cz>
fs/ext4/super.c
fs/ocfs2/quota_global.c
fs/ocfs2/quota_local.c
fs/quota/dquot.c
fs/quota/quota_tree.c
include/linux/quota.h

index 16a877a0f30934467b897e624c7969c0f024f18d..67ce21224dab44fdbd82cae7f4e37bec43fc6bc3 100644 (file)
@@ -5194,7 +5194,7 @@ static int ext4_statfs_project(struct super_block *sb,
        dquot = dqget(sb, qid);
        if (IS_ERR(dquot))
                return PTR_ERR(dquot);
        dquot = dqget(sb, qid);
        if (IS_ERR(dquot))
                return PTR_ERR(dquot);
-       spin_lock(&dq_data_lock);
+       spin_lock(&dquot->dq_dqb_lock);
 
        limit = (dquot->dq_dqb.dqb_bsoftlimit ?
                 dquot->dq_dqb.dqb_bsoftlimit :
 
        limit = (dquot->dq_dqb.dqb_bsoftlimit ?
                 dquot->dq_dqb.dqb_bsoftlimit :
@@ -5217,7 +5217,7 @@ static int ext4_statfs_project(struct super_block *sb,
                         (buf->f_files - dquot->dq_dqb.dqb_curinodes) : 0;
        }
 
                         (buf->f_files - dquot->dq_dqb.dqb_curinodes) : 0;
        }
 
-       spin_unlock(&dq_data_lock);
+       spin_unlock(&dquot->dq_dqb_lock);
        dqput(dquot);
        return 0;
 }
        dqput(dquot);
        return 0;
 }
index 78f3a869748c5c24eab7a5ffc8bd729dceb81b23..c94b6baaa55128b7cf9bec5961f6aecee446fa38 100644 (file)
@@ -504,7 +504,7 @@ int __ocfs2_sync_dquot(struct dquot *dquot, int freeing)
        /* Update space and inode usage. Get also other information from
         * global quota file so that we don't overwrite any changes there.
         * We are */
        /* Update space and inode usage. Get also other information from
         * global quota file so that we don't overwrite any changes there.
         * We are */
-       spin_lock(&dq_data_lock);
+       spin_lock(&dquot->dq_dqb_lock);
        spacechange = dquot->dq_dqb.dqb_curspace -
                                        OCFS2_DQUOT(dquot)->dq_origspace;
        inodechange = dquot->dq_dqb.dqb_curinodes -
        spacechange = dquot->dq_dqb.dqb_curspace -
                                        OCFS2_DQUOT(dquot)->dq_origspace;
        inodechange = dquot->dq_dqb.dqb_curinodes -
@@ -560,7 +560,7 @@ int __ocfs2_sync_dquot(struct dquot *dquot, int freeing)
        __clear_bit(DQ_LASTSET_B + QIF_ITIME_B, &dquot->dq_flags);
        OCFS2_DQUOT(dquot)->dq_origspace = dquot->dq_dqb.dqb_curspace;
        OCFS2_DQUOT(dquot)->dq_originodes = dquot->dq_dqb.dqb_curinodes;
        __clear_bit(DQ_LASTSET_B + QIF_ITIME_B, &dquot->dq_flags);
        OCFS2_DQUOT(dquot)->dq_origspace = dquot->dq_dqb.dqb_curspace;
        OCFS2_DQUOT(dquot)->dq_originodes = dquot->dq_dqb.dqb_curinodes;
-       spin_unlock(&dq_data_lock);
+       spin_unlock(&dquot->dq_dqb_lock);
        err = ocfs2_qinfo_lock(info, freeing);
        if (err < 0) {
                mlog(ML_ERROR, "Failed to lock quota info, losing quota write"
        err = ocfs2_qinfo_lock(info, freeing);
        if (err < 0) {
                mlog(ML_ERROR, "Failed to lock quota info, losing quota write"
@@ -924,10 +924,10 @@ static int ocfs2_mark_dquot_dirty(struct dquot *dquot)
 
        /* In case user set some limits, sync dquot immediately to global
         * quota file so that information propagates quicker */
 
        /* In case user set some limits, sync dquot immediately to global
         * quota file so that information propagates quicker */
-       spin_lock(&dq_data_lock);
+       spin_lock(&dquot->dq_dqb_lock);
        if (dquot->dq_flags & mask)
                sync = 1;
        if (dquot->dq_flags & mask)
                sync = 1;
-       spin_unlock(&dq_data_lock);
+       spin_unlock(&dquot->dq_dqb_lock);
        /* This is a slight hack but we can't afford getting global quota
         * lock if we already have a transaction started. */
        if (!sync || journal_current_handle()) {
        /* This is a slight hack but we can't afford getting global quota
         * lock if we already have a transaction started. */
        if (!sync || journal_current_handle()) {
index 2eeedcc2e9da06276bebf2d72d615806d3ea8189..aa700fd10610baf8b022fc17581cd200e13c22ec 100644 (file)
@@ -521,7 +521,7 @@ static int ocfs2_recover_local_quota_file(struct inode *lqinode,
                                goto out_drop_lock;
                        }
                        down_write(&sb_dqopt(sb)->dqio_sem);
                                goto out_drop_lock;
                        }
                        down_write(&sb_dqopt(sb)->dqio_sem);
-                       spin_lock(&dq_data_lock);
+                       spin_lock(&dquot->dq_dqb_lock);
                        /* Add usage from quota entry into quota changes
                         * of our node. Auxiliary variables are important
                         * due to signedness */
                        /* Add usage from quota entry into quota changes
                         * of our node. Auxiliary variables are important
                         * due to signedness */
@@ -529,7 +529,7 @@ static int ocfs2_recover_local_quota_file(struct inode *lqinode,
                        inodechange = le64_to_cpu(dqblk->dqb_inodemod);
                        dquot->dq_dqb.dqb_curspace += spacechange;
                        dquot->dq_dqb.dqb_curinodes += inodechange;
                        inodechange = le64_to_cpu(dqblk->dqb_inodemod);
                        dquot->dq_dqb.dqb_curspace += spacechange;
                        dquot->dq_dqb.dqb_curinodes += inodechange;
-                       spin_unlock(&dq_data_lock);
+                       spin_unlock(&dquot->dq_dqb_lock);
                        /* We want to drop reference held by the crashed
                         * node. Since we have our own reference we know
                         * global structure actually won't be freed. */
                        /* We want to drop reference held by the crashed
                         * node. Since we have our own reference we know
                         * global structure actually won't be freed. */
@@ -877,12 +877,12 @@ static void olq_set_dquot(struct buffer_head *bh, void *private)
 
        dqblk->dqb_id = cpu_to_le64(from_kqid(&init_user_ns,
                                              od->dq_dquot.dq_id));
 
        dqblk->dqb_id = cpu_to_le64(from_kqid(&init_user_ns,
                                              od->dq_dquot.dq_id));
-       spin_lock(&dq_data_lock);
+       spin_lock(&od->dq_dquot.dq_dqb_lock);
        dqblk->dqb_spacemod = cpu_to_le64(od->dq_dquot.dq_dqb.dqb_curspace -
                                          od->dq_origspace);
        dqblk->dqb_inodemod = cpu_to_le64(od->dq_dquot.dq_dqb.dqb_curinodes -
                                          od->dq_originodes);
        dqblk->dqb_spacemod = cpu_to_le64(od->dq_dquot.dq_dqb.dqb_curspace -
                                          od->dq_origspace);
        dqblk->dqb_inodemod = cpu_to_le64(od->dq_dquot.dq_dqb.dqb_curinodes -
                                          od->dq_originodes);
-       spin_unlock(&dq_data_lock);
+       spin_unlock(&od->dq_dquot.dq_dqb_lock);
        trace_olq_set_dquot(
                (unsigned long long)le64_to_cpu(dqblk->dqb_spacemod),
                (unsigned long long)le64_to_cpu(dqblk->dqb_inodemod),
        trace_olq_set_dquot(
                (unsigned long long)le64_to_cpu(dqblk->dqb_spacemod),
                (unsigned long long)le64_to_cpu(dqblk->dqb_inodemod),
index 411142a2f074786c02b81308efca5427469edc0e..d51797f850c5106d3d099ccbe2b012596097e4eb 100644 (file)
 #include <linux/uaccess.h>
 
 /*
 #include <linux/uaccess.h>
 
 /*
- * There are three quota SMP locks. dq_list_lock protects all lists with quotas
- * and quota formats.
- * dq_data_lock protects data from dq_dqb and also mem_dqinfo structures and
- * also guards consistency of dquot->dq_dqb with inode->i_blocks, i_bytes.
- * i_blocks and i_bytes updates itself are guarded by i_lock acquired directly
- * in inode_add_bytes() and inode_sub_bytes(). dq_state_lock protects
- * modifications of quota state (on quotaon and quotaoff) and readers who care
- * about latest values take it as well.
+ * There are five quota SMP locks:
+ * * dq_list_lock protects all lists with quotas and quota formats.
+ * * dquot->dq_dqb_lock protects data from dq_dqb
+ * * inode->i_lock protects inode->i_blocks, i_bytes and also guards
+ *   consistency of dquot->dq_dqb with inode->i_blocks, i_bytes so that
+ *   dquot_transfer() can stabilize amount it transfers
+ * * dq_data_lock protects mem_dqinfo structures and modifications of dquot
+ *   pointers in the inode
+ * * dq_state_lock protects modifications of quota state (on quotaon and
+ *   quotaoff) and readers who care about latest values take it as well.
  *
  *
- * The spinlock ordering is hence: dq_data_lock > dq_list_lock > i_lock,
+ * The spinlock ordering is hence:
+ *   dq_data_lock > dq_list_lock > i_lock > dquot->dq_dqb_lock,
  *   dq_list_lock > dq_state_lock
  *
  * Note that some things (eg. sb pointer, type, id) doesn't change during
  *   dq_list_lock > dq_state_lock
  *
  * Note that some things (eg. sb pointer, type, id) doesn't change during
@@ -246,6 +249,7 @@ struct dqstats dqstats;
 EXPORT_SYMBOL(dqstats);
 
 static qsize_t inode_get_rsv_space(struct inode *inode);
 EXPORT_SYMBOL(dqstats);
 
 static qsize_t inode_get_rsv_space(struct inode *inode);
+static qsize_t __inode_get_rsv_space(struct inode *inode);
 static int __dquot_initialize(struct inode *inode, int type);
 
 static inline unsigned int
 static int __dquot_initialize(struct inode *inode, int type);
 
 static inline unsigned int
@@ -816,6 +820,7 @@ static struct dquot *get_empty_dquot(struct super_block *sb, int type)
        dquot->dq_sb = sb;
        dquot->dq_id = make_kqid_invalid(type);
        atomic_set(&dquot->dq_count, 1);
        dquot->dq_sb = sb;
        dquot->dq_id = make_kqid_invalid(type);
        atomic_set(&dquot->dq_count, 1);
+       spin_lock_init(&dquot->dq_dqb_lock);
 
        return dquot;
 }
 
        return dquot;
 }
@@ -1073,21 +1078,6 @@ static void drop_dquot_ref(struct super_block *sb, int type)
        }
 }
 
        }
 }
 
-static inline void dquot_incr_inodes(struct dquot *dquot, qsize_t number)
-{
-       dquot->dq_dqb.dqb_curinodes += number;
-}
-
-static inline void dquot_incr_space(struct dquot *dquot, qsize_t number)
-{
-       dquot->dq_dqb.dqb_curspace += number;
-}
-
-static inline void dquot_resv_space(struct dquot *dquot, qsize_t number)
-{
-       dquot->dq_dqb.dqb_rsvspace += number;
-}
-
 static inline
 void dquot_free_reserved_space(struct dquot *dquot, qsize_t number)
 {
 static inline
 void dquot_free_reserved_space(struct dquot *dquot, qsize_t number)
 {
@@ -1246,21 +1236,24 @@ static int ignore_hardlimit(struct dquot *dquot)
                !(info->dqi_flags & DQF_ROOT_SQUASH));
 }
 
                !(info->dqi_flags & DQF_ROOT_SQUASH));
 }
 
-/* needs dq_data_lock */
-static int check_idq(struct dquot *dquot, qsize_t inodes,
-                    struct dquot_warn *warn)
+static int dquot_add_inodes(struct dquot *dquot, qsize_t inodes,
+                           struct dquot_warn *warn)
 {
 {
-       qsize_t newinodes = dquot->dq_dqb.dqb_curinodes + inodes;
+       qsize_t newinodes;
+       int ret = 0;
 
 
+       spin_lock(&dquot->dq_dqb_lock);
+       newinodes = dquot->dq_dqb.dqb_curinodes + inodes;
        if (!sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_id.type) ||
            test_bit(DQ_FAKE_B, &dquot->dq_flags))
        if (!sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_id.type) ||
            test_bit(DQ_FAKE_B, &dquot->dq_flags))
-               return 0;
+               goto add;
 
        if (dquot->dq_dqb.dqb_ihardlimit &&
            newinodes > dquot->dq_dqb.dqb_ihardlimit &&
             !ignore_hardlimit(dquot)) {
                prepare_warning(warn, dquot, QUOTA_NL_IHARDWARN);
 
        if (dquot->dq_dqb.dqb_ihardlimit &&
            newinodes > dquot->dq_dqb.dqb_ihardlimit &&
             !ignore_hardlimit(dquot)) {
                prepare_warning(warn, dquot, QUOTA_NL_IHARDWARN);
-               return -EDQUOT;
+               ret = -EDQUOT;
+               goto out;
        }
 
        if (dquot->dq_dqb.dqb_isoftlimit &&
        }
 
        if (dquot->dq_dqb.dqb_isoftlimit &&
@@ -1269,7 +1262,8 @@ static int check_idq(struct dquot *dquot, qsize_t inodes,
            ktime_get_real_seconds() >= dquot->dq_dqb.dqb_itime &&
             !ignore_hardlimit(dquot)) {
                prepare_warning(warn, dquot, QUOTA_NL_ISOFTLONGWARN);
            ktime_get_real_seconds() >= dquot->dq_dqb.dqb_itime &&
             !ignore_hardlimit(dquot)) {
                prepare_warning(warn, dquot, QUOTA_NL_ISOFTLONGWARN);
-               return -EDQUOT;
+               ret = -EDQUOT;
+               goto out;
        }
 
        if (dquot->dq_dqb.dqb_isoftlimit &&
        }
 
        if (dquot->dq_dqb.dqb_isoftlimit &&
@@ -1279,30 +1273,40 @@ static int check_idq(struct dquot *dquot, qsize_t inodes,
                dquot->dq_dqb.dqb_itime = ktime_get_real_seconds() +
                    sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type].dqi_igrace;
        }
                dquot->dq_dqb.dqb_itime = ktime_get_real_seconds() +
                    sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type].dqi_igrace;
        }
+add:
+       dquot->dq_dqb.dqb_curinodes = newinodes;
 
 
-       return 0;
+out:
+       spin_unlock(&dquot->dq_dqb_lock);
+       return ret;
 }
 
 }
 
-/* needs dq_data_lock */
-static int check_bdq(struct dquot *dquot, qsize_t space, int prealloc,
-                    struct dquot_warn *warn)
+static int dquot_add_space(struct dquot *dquot, qsize_t space,
+                          qsize_t rsv_space, unsigned int flags,
+                          struct dquot_warn *warn)
 {
        qsize_t tspace;
        struct super_block *sb = dquot->dq_sb;
 {
        qsize_t tspace;
        struct super_block *sb = dquot->dq_sb;
+       int ret = 0;
 
 
+       spin_lock(&dquot->dq_dqb_lock);
        if (!sb_has_quota_limits_enabled(sb, dquot->dq_id.type) ||
            test_bit(DQ_FAKE_B, &dquot->dq_flags))
        if (!sb_has_quota_limits_enabled(sb, dquot->dq_id.type) ||
            test_bit(DQ_FAKE_B, &dquot->dq_flags))
-               return 0;
+               goto add;
 
        tspace = dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace
 
        tspace = dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace
-               + space;
+               + space + rsv_space;
+
+       if (flags & DQUOT_SPACE_NOFAIL)
+               goto add;
 
        if (dquot->dq_dqb.dqb_bhardlimit &&
            tspace > dquot->dq_dqb.dqb_bhardlimit &&
             !ignore_hardlimit(dquot)) {
 
        if (dquot->dq_dqb.dqb_bhardlimit &&
            tspace > dquot->dq_dqb.dqb_bhardlimit &&
             !ignore_hardlimit(dquot)) {
-               if (!prealloc)
+               if (flags & DQUOT_SPACE_WARN)
                        prepare_warning(warn, dquot, QUOTA_NL_BHARDWARN);
                        prepare_warning(warn, dquot, QUOTA_NL_BHARDWARN);
-               return -EDQUOT;
+               ret = -EDQUOT;
+               goto out;
        }
 
        if (dquot->dq_dqb.dqb_bsoftlimit &&
        }
 
        if (dquot->dq_dqb.dqb_bsoftlimit &&
@@ -1310,28 +1314,34 @@ static int check_bdq(struct dquot *dquot, qsize_t space, int prealloc,
            dquot->dq_dqb.dqb_btime &&
            ktime_get_real_seconds() >= dquot->dq_dqb.dqb_btime &&
             !ignore_hardlimit(dquot)) {
            dquot->dq_dqb.dqb_btime &&
            ktime_get_real_seconds() >= dquot->dq_dqb.dqb_btime &&
             !ignore_hardlimit(dquot)) {
-               if (!prealloc)
+               if (flags & DQUOT_SPACE_WARN)
                        prepare_warning(warn, dquot, QUOTA_NL_BSOFTLONGWARN);
                        prepare_warning(warn, dquot, QUOTA_NL_BSOFTLONGWARN);
-               return -EDQUOT;
+               ret = -EDQUOT;
+               goto out;
        }
 
        if (dquot->dq_dqb.dqb_bsoftlimit &&
            tspace > dquot->dq_dqb.dqb_bsoftlimit &&
            dquot->dq_dqb.dqb_btime == 0) {
        }
 
        if (dquot->dq_dqb.dqb_bsoftlimit &&
            tspace > dquot->dq_dqb.dqb_bsoftlimit &&
            dquot->dq_dqb.dqb_btime == 0) {
-               if (!prealloc) {
+               if (flags & DQUOT_SPACE_WARN) {
                        prepare_warning(warn, dquot, QUOTA_NL_BSOFTWARN);
                        dquot->dq_dqb.dqb_btime = ktime_get_real_seconds() +
                            sb_dqopt(sb)->info[dquot->dq_id.type].dqi_bgrace;
                        prepare_warning(warn, dquot, QUOTA_NL_BSOFTWARN);
                        dquot->dq_dqb.dqb_btime = ktime_get_real_seconds() +
                            sb_dqopt(sb)->info[dquot->dq_id.type].dqi_bgrace;
-               }
-               else
+               } else {
                        /*
                         * We don't allow preallocation to exceed softlimit so exceeding will
                         * be always printed
                         */
                        /*
                         * We don't allow preallocation to exceed softlimit so exceeding will
                         * be always printed
                         */
-                       return -EDQUOT;
+                       ret = -EDQUOT;
+                       goto out;
+               }
        }
        }
-
-       return 0;
+add:
+       dquot->dq_dqb.dqb_rsvspace += rsv_space;
+       dquot->dq_dqb.dqb_curspace += space;
+out:
+       spin_unlock(&dquot->dq_dqb_lock);
+       return ret;
 }
 
 static int info_idq_free(struct dquot *dquot, qsize_t inodes)
 }
 
 static int info_idq_free(struct dquot *dquot, qsize_t inodes)
@@ -1466,8 +1476,15 @@ static int __dquot_initialize(struct inode *inode, int type)
                         * did a write before quota was turned on
                         */
                        rsv = inode_get_rsv_space(inode);
                         * did a write before quota was turned on
                         */
                        rsv = inode_get_rsv_space(inode);
-                       if (unlikely(rsv))
-                               dquot_resv_space(dquots[cnt], rsv);
+                       if (unlikely(rsv)) {
+                               spin_lock(&inode->i_lock);
+                               /* Get reservation again under proper lock */
+                               rsv = __inode_get_rsv_space(inode);
+                               spin_lock(&dquots[cnt]->dq_dqb_lock);
+                               dquots[cnt]->dq_dqb.dqb_rsvspace += rsv;
+                               spin_unlock(&dquots[cnt]->dq_dqb_lock);
+                               spin_unlock(&inode->i_lock);
+                       }
                }
        }
 out_lock:
                }
        }
 out_lock:
@@ -1562,6 +1579,13 @@ static qsize_t *inode_reserved_space(struct inode * inode)
        return inode->i_sb->dq_op->get_reserved_space(inode);
 }
 
        return inode->i_sb->dq_op->get_reserved_space(inode);
 }
 
+static qsize_t __inode_get_rsv_space(struct inode *inode)
+{
+       if (!inode->i_sb->dq_op->get_reserved_space)
+               return 0;
+       return *inode_reserved_space(inode);
+}
+
 static qsize_t inode_get_rsv_space(struct inode *inode)
 {
        qsize_t ret;
 static qsize_t inode_get_rsv_space(struct inode *inode)
 {
        qsize_t ret;
@@ -1569,7 +1593,7 @@ static qsize_t inode_get_rsv_space(struct inode *inode)
        if (!inode->i_sb->dq_op->get_reserved_space)
                return 0;
        spin_lock(&inode->i_lock);
        if (!inode->i_sb->dq_op->get_reserved_space)
                return 0;
        spin_lock(&inode->i_lock);
-       ret = *inode_reserved_space(inode);
+       ret = __inode_get_rsv_space(inode);
        spin_unlock(&inode->i_lock);
        return ret;
 }
        spin_unlock(&inode->i_lock);
        return ret;
 }
@@ -1610,33 +1634,41 @@ int __dquot_alloc_space(struct inode *inode, qsize_t number, int flags)
 
        dquots = i_dquot(inode);
        index = srcu_read_lock(&dquot_srcu);
 
        dquots = i_dquot(inode);
        index = srcu_read_lock(&dquot_srcu);
-       spin_lock(&dq_data_lock);
+       spin_lock(&inode->i_lock);
        for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
                if (!dquots[cnt])
                        continue;
        for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
                if (!dquots[cnt])
                        continue;
-               ret = check_bdq(dquots[cnt], number,
-                               !(flags & DQUOT_SPACE_WARN), &warn[cnt]);
-               if (ret && !(flags & DQUOT_SPACE_NOFAIL)) {
-                       spin_unlock(&dq_data_lock);
+               if (flags & DQUOT_SPACE_RESERVE) {
+                       ret = dquot_add_space(dquots[cnt], 0, number, flags,
+                                             &warn[cnt]);
+               } else {
+                       ret = dquot_add_space(dquots[cnt], number, 0, flags,
+                                             &warn[cnt]);
+               }
+               if (ret) {
+                       /* Back out changes we already did */
+                       for (cnt--; cnt >= 0; cnt--) {
+                               if (!dquots[cnt])
+                                       continue;
+                               spin_lock(&dquots[cnt]->dq_dqb_lock);
+                               if (flags & DQUOT_SPACE_RESERVE) {
+                                       dquots[cnt]->dq_dqb.dqb_rsvspace -=
+                                                                       number;
+                               } else {
+                                       dquots[cnt]->dq_dqb.dqb_curspace -=
+                                                                       number;
+                               }
+                               spin_unlock(&dquots[cnt]->dq_dqb_lock);
+                       }
+                       spin_unlock(&inode->i_lock);
                        goto out_flush_warn;
                }
        }
                        goto out_flush_warn;
                }
        }
-       for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
-               if (!dquots[cnt])
-                       continue;
-               if (reserve)
-                       dquot_resv_space(dquots[cnt], number);
-               else
-                       dquot_incr_space(dquots[cnt], number);
-       }
-       if (reserve) {
-               spin_lock(&inode->i_lock);
+       if (reserve)
                *inode_reserved_space(inode) += number;
                *inode_reserved_space(inode) += number;
-               spin_unlock(&inode->i_lock);
-       } else {
-               inode_add_bytes(inode, number);
-       }
-       spin_unlock(&dq_data_lock);
+       else
+               __inode_add_bytes(inode, number);
+       spin_unlock(&inode->i_lock);
 
        if (reserve)
                goto out_flush_warn;
 
        if (reserve)
                goto out_flush_warn;
@@ -1665,23 +1697,26 @@ int dquot_alloc_inode(struct inode *inode)
 
        dquots = i_dquot(inode);
        index = srcu_read_lock(&dquot_srcu);
 
        dquots = i_dquot(inode);
        index = srcu_read_lock(&dquot_srcu);
-       spin_lock(&dq_data_lock);
+       spin_lock(&inode->i_lock);
        for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
                if (!dquots[cnt])
                        continue;
        for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
                if (!dquots[cnt])
                        continue;
-               ret = check_idq(dquots[cnt], 1, &warn[cnt]);
-               if (ret)
+               ret = dquot_add_inodes(dquots[cnt], 1, &warn[cnt]);
+               if (ret) {
+                       for (cnt--; cnt >= 0; cnt--) {
+                               if (!dquots[cnt])
+                                       continue;
+                               /* Back out changes we already did */
+                               spin_lock(&dquots[cnt]->dq_dqb_lock);
+                               dquots[cnt]->dq_dqb.dqb_curinodes--;
+                               spin_unlock(&dquots[cnt]->dq_dqb_lock);
+                       }
                        goto warn_put_all;
                        goto warn_put_all;
-       }
-
-       for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
-               if (!dquots[cnt])
-                       continue;
-               dquot_incr_inodes(dquots[cnt], 1);
+               }
        }
 
 warn_put_all:
        }
 
 warn_put_all:
-       spin_unlock(&dq_data_lock);
+       spin_unlock(&inode->i_lock);
        if (ret == 0)
                mark_all_dquot_dirty(dquots);
        srcu_read_unlock(&dquot_srcu, index);
        if (ret == 0)
                mark_all_dquot_dirty(dquots);
        srcu_read_unlock(&dquot_srcu, index);
@@ -1708,24 +1743,24 @@ int dquot_claim_space_nodirty(struct inode *inode, qsize_t number)
 
        dquots = i_dquot(inode);
        index = srcu_read_lock(&dquot_srcu);
 
        dquots = i_dquot(inode);
        index = srcu_read_lock(&dquot_srcu);
-       spin_lock(&dq_data_lock);
+       spin_lock(&inode->i_lock);
        /* Claim reserved quotas to allocated quotas */
        for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
                if (dquots[cnt]) {
                        struct dquot *dquot = dquots[cnt];
 
        /* Claim reserved quotas to allocated quotas */
        for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
                if (dquots[cnt]) {
                        struct dquot *dquot = dquots[cnt];
 
+                       spin_lock(&dquot->dq_dqb_lock);
                        if (WARN_ON_ONCE(dquot->dq_dqb.dqb_rsvspace < number))
                                number = dquot->dq_dqb.dqb_rsvspace;
                        dquot->dq_dqb.dqb_curspace += number;
                        dquot->dq_dqb.dqb_rsvspace -= number;
                        if (WARN_ON_ONCE(dquot->dq_dqb.dqb_rsvspace < number))
                                number = dquot->dq_dqb.dqb_rsvspace;
                        dquot->dq_dqb.dqb_curspace += number;
                        dquot->dq_dqb.dqb_rsvspace -= number;
+                       spin_unlock(&dquot->dq_dqb_lock);
                }
        }
        /* Update inode bytes */
                }
        }
        /* Update inode bytes */
-       spin_lock(&inode->i_lock);
        *inode_reserved_space(inode) -= number;
        __inode_add_bytes(inode, number);
        spin_unlock(&inode->i_lock);
        *inode_reserved_space(inode) -= number;
        __inode_add_bytes(inode, number);
        spin_unlock(&inode->i_lock);
-       spin_unlock(&dq_data_lock);
        mark_all_dquot_dirty(dquots);
        srcu_read_unlock(&dquot_srcu, index);
        return 0;
        mark_all_dquot_dirty(dquots);
        srcu_read_unlock(&dquot_srcu, index);
        return 0;
@@ -1750,24 +1785,24 @@ void dquot_reclaim_space_nodirty(struct inode *inode, qsize_t number)
 
        dquots = i_dquot(inode);
        index = srcu_read_lock(&dquot_srcu);
 
        dquots = i_dquot(inode);
        index = srcu_read_lock(&dquot_srcu);
-       spin_lock(&dq_data_lock);
+       spin_lock(&inode->i_lock);
        /* Claim reserved quotas to allocated quotas */
        for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
                if (dquots[cnt]) {
                        struct dquot *dquot = dquots[cnt];
 
        /* Claim reserved quotas to allocated quotas */
        for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
                if (dquots[cnt]) {
                        struct dquot *dquot = dquots[cnt];
 
+                       spin_lock(&dquot->dq_dqb_lock);
                        if (WARN_ON_ONCE(dquot->dq_dqb.dqb_curspace < number))
                                number = dquot->dq_dqb.dqb_curspace;
                        dquot->dq_dqb.dqb_rsvspace += number;
                        dquot->dq_dqb.dqb_curspace -= number;
                        if (WARN_ON_ONCE(dquot->dq_dqb.dqb_curspace < number))
                                number = dquot->dq_dqb.dqb_curspace;
                        dquot->dq_dqb.dqb_rsvspace += number;
                        dquot->dq_dqb.dqb_curspace -= number;
+                       spin_unlock(&dquot->dq_dqb_lock);
                }
        }
        /* Update inode bytes */
                }
        }
        /* Update inode bytes */
-       spin_lock(&inode->i_lock);
        *inode_reserved_space(inode) += number;
        __inode_sub_bytes(inode, number);
        spin_unlock(&inode->i_lock);
        *inode_reserved_space(inode) += number;
        __inode_sub_bytes(inode, number);
        spin_unlock(&inode->i_lock);
-       spin_unlock(&dq_data_lock);
        mark_all_dquot_dirty(dquots);
        srcu_read_unlock(&dquot_srcu, index);
        return;
        mark_all_dquot_dirty(dquots);
        srcu_read_unlock(&dquot_srcu, index);
        return;
@@ -1797,13 +1832,14 @@ void __dquot_free_space(struct inode *inode, qsize_t number, int flags)
 
        dquots = i_dquot(inode);
        index = srcu_read_lock(&dquot_srcu);
 
        dquots = i_dquot(inode);
        index = srcu_read_lock(&dquot_srcu);
-       spin_lock(&dq_data_lock);
+       spin_lock(&inode->i_lock);
        for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
                int wtype;
 
                warn[cnt].w_type = QUOTA_NL_NOWARN;
                if (!dquots[cnt])
                        continue;
        for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
                int wtype;
 
                warn[cnt].w_type = QUOTA_NL_NOWARN;
                if (!dquots[cnt])
                        continue;
+               spin_lock(&dquots[cnt]->dq_dqb_lock);
                wtype = info_bdq_free(dquots[cnt], number);
                if (wtype != QUOTA_NL_NOWARN)
                        prepare_warning(&warn[cnt], dquots[cnt], wtype);
                wtype = info_bdq_free(dquots[cnt], number);
                if (wtype != QUOTA_NL_NOWARN)
                        prepare_warning(&warn[cnt], dquots[cnt], wtype);
@@ -1811,15 +1847,13 @@ void __dquot_free_space(struct inode *inode, qsize_t number, int flags)
                        dquot_free_reserved_space(dquots[cnt], number);
                else
                        dquot_decr_space(dquots[cnt], number);
                        dquot_free_reserved_space(dquots[cnt], number);
                else
                        dquot_decr_space(dquots[cnt], number);
+               spin_unlock(&dquots[cnt]->dq_dqb_lock);
        }
        }
-       if (reserve) {
-               spin_lock(&inode->i_lock);
+       if (reserve)
                *inode_reserved_space(inode) -= number;
                *inode_reserved_space(inode) -= number;
-               spin_unlock(&inode->i_lock);
-       } else {
-               inode_sub_bytes(inode, number);
-       }
-       spin_unlock(&dq_data_lock);
+       else
+               __inode_sub_bytes(inode, number);
+       spin_unlock(&inode->i_lock);
 
        if (reserve)
                goto out_unlock;
 
        if (reserve)
                goto out_unlock;
@@ -1845,19 +1879,21 @@ void dquot_free_inode(struct inode *inode)
 
        dquots = i_dquot(inode);
        index = srcu_read_lock(&dquot_srcu);
 
        dquots = i_dquot(inode);
        index = srcu_read_lock(&dquot_srcu);
-       spin_lock(&dq_data_lock);
+       spin_lock(&inode->i_lock);
        for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
                int wtype;
 
                warn[cnt].w_type = QUOTA_NL_NOWARN;
                if (!dquots[cnt])
                        continue;
        for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
                int wtype;
 
                warn[cnt].w_type = QUOTA_NL_NOWARN;
                if (!dquots[cnt])
                        continue;
+               spin_lock(&dquots[cnt]->dq_dqb_lock);
                wtype = info_idq_free(dquots[cnt], 1);
                if (wtype != QUOTA_NL_NOWARN)
                        prepare_warning(&warn[cnt], dquots[cnt], wtype);
                dquot_decr_inodes(dquots[cnt], 1);
                wtype = info_idq_free(dquots[cnt], 1);
                if (wtype != QUOTA_NL_NOWARN)
                        prepare_warning(&warn[cnt], dquots[cnt], wtype);
                dquot_decr_inodes(dquots[cnt], 1);
+               spin_unlock(&dquots[cnt]->dq_dqb_lock);
        }
        }
-       spin_unlock(&dq_data_lock);
+       spin_unlock(&inode->i_lock);
        mark_all_dquot_dirty(dquots);
        srcu_read_unlock(&dquot_srcu, index);
        flush_warnings(warn);
        mark_all_dquot_dirty(dquots);
        srcu_read_unlock(&dquot_srcu, index);
        flush_warnings(warn);
@@ -1878,7 +1914,7 @@ EXPORT_SYMBOL(dquot_free_inode);
  */
 int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
 {
  */
 int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
 {
-       qsize_t space, cur_space;
+       qsize_t cur_space;
        qsize_t rsv_space = 0;
        qsize_t inode_usage = 1;
        struct dquot *transfer_from[MAXQUOTAS] = {};
        qsize_t rsv_space = 0;
        qsize_t inode_usage = 1;
        struct dquot *transfer_from[MAXQUOTAS] = {};
@@ -1905,14 +1941,18 @@ int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
        }
 
        spin_lock(&dq_data_lock);
        }
 
        spin_lock(&dq_data_lock);
+       spin_lock(&inode->i_lock);
        if (IS_NOQUOTA(inode)) {        /* File without quota accounting? */
        if (IS_NOQUOTA(inode)) {        /* File without quota accounting? */
+               spin_unlock(&inode->i_lock);
                spin_unlock(&dq_data_lock);
                return 0;
        }
                spin_unlock(&dq_data_lock);
                return 0;
        }
-       cur_space = inode_get_bytes(inode);
-       rsv_space = inode_get_rsv_space(inode);
-       space = cur_space + rsv_space;
-       /* Build the transfer_from list and check the limits */
+       cur_space = __inode_get_bytes(inode);
+       rsv_space = __inode_get_rsv_space(inode);
+       /*
+        * Build the transfer_from list, check limits, and update usage in
+        * the target structures.
+        */
        for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
                /*
                 * Skip changes for same uid or gid or for turned off quota-type.
        for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
                /*
                 * Skip changes for same uid or gid or for turned off quota-type.
@@ -1924,28 +1964,33 @@ int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
                        continue;
                is_valid[cnt] = 1;
                transfer_from[cnt] = i_dquot(inode)[cnt];
                        continue;
                is_valid[cnt] = 1;
                transfer_from[cnt] = i_dquot(inode)[cnt];
-               ret = check_idq(transfer_to[cnt], inode_usage, &warn_to[cnt]);
+               ret = dquot_add_inodes(transfer_to[cnt], inode_usage,
+                                      &warn_to[cnt]);
                if (ret)
                        goto over_quota;
                if (ret)
                        goto over_quota;
-               ret = check_bdq(transfer_to[cnt], space, 0, &warn_to[cnt]);
-               if (ret)
+               ret = dquot_add_space(transfer_to[cnt], cur_space, rsv_space, 0,
+                                     &warn_to[cnt]);
+               if (ret) {
+                       dquot_decr_inodes(transfer_to[cnt], inode_usage);
                        goto over_quota;
                        goto over_quota;
+               }
        }
 
        }
 
-       /*
-        * Finally perform the needed transfer from transfer_from to transfer_to
-        */
+       /* Decrease usage for source structures and update quota pointers */
        for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
                if (!is_valid[cnt])
                        continue;
                /* Due to IO error we might not have transfer_from[] structure */
                if (transfer_from[cnt]) {
                        int wtype;
        for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
                if (!is_valid[cnt])
                        continue;
                /* Due to IO error we might not have transfer_from[] structure */
                if (transfer_from[cnt]) {
                        int wtype;
+
+                       spin_lock(&transfer_from[cnt]->dq_dqb_lock);
                        wtype = info_idq_free(transfer_from[cnt], inode_usage);
                        if (wtype != QUOTA_NL_NOWARN)
                                prepare_warning(&warn_from_inodes[cnt],
                                                transfer_from[cnt], wtype);
                        wtype = info_idq_free(transfer_from[cnt], inode_usage);
                        if (wtype != QUOTA_NL_NOWARN)
                                prepare_warning(&warn_from_inodes[cnt],
                                                transfer_from[cnt], wtype);
-                       wtype = info_bdq_free(transfer_from[cnt], space);
+                       wtype = info_bdq_free(transfer_from[cnt],
+                                             cur_space + rsv_space);
                        if (wtype != QUOTA_NL_NOWARN)
                                prepare_warning(&warn_from_space[cnt],
                                                transfer_from[cnt], wtype);
                        if (wtype != QUOTA_NL_NOWARN)
                                prepare_warning(&warn_from_space[cnt],
                                                transfer_from[cnt], wtype);
@@ -1953,14 +1998,11 @@ int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
                        dquot_decr_space(transfer_from[cnt], cur_space);
                        dquot_free_reserved_space(transfer_from[cnt],
                                                  rsv_space);
                        dquot_decr_space(transfer_from[cnt], cur_space);
                        dquot_free_reserved_space(transfer_from[cnt],
                                                  rsv_space);
+                       spin_unlock(&transfer_from[cnt]->dq_dqb_lock);
                }
                }
-
-               dquot_incr_inodes(transfer_to[cnt], inode_usage);
-               dquot_incr_space(transfer_to[cnt], cur_space);
-               dquot_resv_space(transfer_to[cnt], rsv_space);
-
                i_dquot(inode)[cnt] = transfer_to[cnt];
        }
                i_dquot(inode)[cnt] = transfer_to[cnt];
        }
+       spin_unlock(&inode->i_lock);
        spin_unlock(&dq_data_lock);
 
        mark_all_dquot_dirty(transfer_from);
        spin_unlock(&dq_data_lock);
 
        mark_all_dquot_dirty(transfer_from);
@@ -1974,6 +2016,17 @@ int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
                        transfer_to[cnt] = transfer_from[cnt];
        return 0;
 over_quota:
                        transfer_to[cnt] = transfer_from[cnt];
        return 0;
 over_quota:
+       /* Back out changes we already did */
+       for (cnt--; cnt >= 0; cnt--) {
+               if (!is_valid[cnt])
+                       continue;
+               spin_lock(&transfer_to[cnt]->dq_dqb_lock);
+               dquot_decr_inodes(transfer_to[cnt], inode_usage);
+               dquot_decr_space(transfer_to[cnt], cur_space);
+               dquot_free_reserved_space(transfer_to[cnt], rsv_space);
+               spin_unlock(&transfer_to[cnt]->dq_dqb_lock);
+       }
+       spin_unlock(&inode->i_lock);
        spin_unlock(&dq_data_lock);
        flush_warnings(warn_to);
        return ret;
        spin_unlock(&dq_data_lock);
        flush_warnings(warn_to);
        return ret;
@@ -2524,7 +2577,7 @@ static void do_get_dqblk(struct dquot *dquot, struct qc_dqblk *di)
        struct mem_dqblk *dm = &dquot->dq_dqb;
 
        memset(di, 0, sizeof(*di));
        struct mem_dqblk *dm = &dquot->dq_dqb;
 
        memset(di, 0, sizeof(*di));
-       spin_lock(&dq_data_lock);
+       spin_lock(&dquot->dq_dqb_lock);
        di->d_spc_hardlimit = dm->dqb_bhardlimit;
        di->d_spc_softlimit = dm->dqb_bsoftlimit;
        di->d_ino_hardlimit = dm->dqb_ihardlimit;
        di->d_spc_hardlimit = dm->dqb_bhardlimit;
        di->d_spc_softlimit = dm->dqb_bsoftlimit;
        di->d_ino_hardlimit = dm->dqb_ihardlimit;
@@ -2533,7 +2586,7 @@ static void do_get_dqblk(struct dquot *dquot, struct qc_dqblk *di)
        di->d_ino_count = dm->dqb_curinodes;
        di->d_spc_timer = dm->dqb_btime;
        di->d_ino_timer = dm->dqb_itime;
        di->d_ino_count = dm->dqb_curinodes;
        di->d_spc_timer = dm->dqb_btime;
        di->d_ino_timer = dm->dqb_itime;
-       spin_unlock(&dq_data_lock);
+       spin_unlock(&dquot->dq_dqb_lock);
 }
 
 int dquot_get_dqblk(struct super_block *sb, struct kqid qid,
 }
 
 int dquot_get_dqblk(struct super_block *sb, struct kqid qid,
@@ -2597,7 +2650,7 @@ static int do_set_dqblk(struct dquot *dquot, struct qc_dqblk *di)
             (di->d_ino_hardlimit > dqi->dqi_max_ino_limit)))
                return -ERANGE;
 
             (di->d_ino_hardlimit > dqi->dqi_max_ino_limit)))
                return -ERANGE;
 
-       spin_lock(&dq_data_lock);
+       spin_lock(&dquot->dq_dqb_lock);
        if (di->d_fieldmask & QC_SPACE) {
                dm->dqb_curspace = di->d_space - dm->dqb_rsvspace;
                check_blim = 1;
        if (di->d_fieldmask & QC_SPACE) {
                dm->dqb_curspace = di->d_space - dm->dqb_rsvspace;
                check_blim = 1;
@@ -2663,7 +2716,7 @@ static int do_set_dqblk(struct dquot *dquot, struct qc_dqblk *di)
                clear_bit(DQ_FAKE_B, &dquot->dq_flags);
        else
                set_bit(DQ_FAKE_B, &dquot->dq_flags);
                clear_bit(DQ_FAKE_B, &dquot->dq_flags);
        else
                set_bit(DQ_FAKE_B, &dquot->dq_flags);
-       spin_unlock(&dq_data_lock);
+       spin_unlock(&dquot->dq_dqb_lock);
        mark_dquot_dirty(dquot);
 
        return 0;
        mark_dquot_dirty(dquot);
 
        return 0;
index 54f85eb2609c83b3277656363e5c2532c4eba4e9..bb3f59bcfcf5b1ee07c2d154fa8b906e4f4c9302 100644 (file)
@@ -389,9 +389,9 @@ int qtree_write_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
                        return ret;
                }
        }
                        return ret;
                }
        }
-       spin_lock(&dq_data_lock);
+       spin_lock(&dquot->dq_dqb_lock);
        info->dqi_ops->mem2disk_dqblk(ddquot, dquot);
        info->dqi_ops->mem2disk_dqblk(ddquot, dquot);
-       spin_unlock(&dq_data_lock);
+       spin_unlock(&dquot->dq_dqb_lock);
        ret = sb->s_op->quota_write(sb, type, ddquot, info->dqi_entry_size,
                                    dquot->dq_off);
        if (ret != info->dqi_entry_size) {
        ret = sb->s_op->quota_write(sb, type, ddquot, info->dqi_entry_size,
                                    dquot->dq_off);
        if (ret != info->dqi_entry_size) {
@@ -649,14 +649,14 @@ int qtree_read_dquot(struct qtree_mem_dqinfo *info, struct dquot *dquot)
                kfree(ddquot);
                goto out;
        }
                kfree(ddquot);
                goto out;
        }
-       spin_lock(&dq_data_lock);
+       spin_lock(&dquot->dq_dqb_lock);
        info->dqi_ops->disk2mem_dqblk(dquot, ddquot);
        if (!dquot->dq_dqb.dqb_bhardlimit &&
            !dquot->dq_dqb.dqb_bsoftlimit &&
            !dquot->dq_dqb.dqb_ihardlimit &&
            !dquot->dq_dqb.dqb_isoftlimit)
                set_bit(DQ_FAKE_B, &dquot->dq_flags);
        info->dqi_ops->disk2mem_dqblk(dquot, ddquot);
        if (!dquot->dq_dqb.dqb_bhardlimit &&
            !dquot->dq_dqb.dqb_bsoftlimit &&
            !dquot->dq_dqb.dqb_ihardlimit &&
            !dquot->dq_dqb.dqb_isoftlimit)
                set_bit(DQ_FAKE_B, &dquot->dq_flags);
-       spin_unlock(&dq_data_lock);
+       spin_unlock(&dquot->dq_dqb_lock);
        kfree(ddquot);
 out:
        dqstats_inc(DQST_READS);
        kfree(ddquot);
 out:
        dqstats_inc(DQST_READS);
index eccc1cb6274e306e0eaf6db3de5877ea41413e22..074123975595d0842dc81cf52bbd33a30b793b06 100644 (file)
@@ -298,12 +298,13 @@ struct dquot {
        struct list_head dq_free;       /* Free list element */
        struct list_head dq_dirty;      /* List of dirty dquots */
        struct mutex dq_lock;           /* dquot IO lock */
        struct list_head dq_free;       /* Free list element */
        struct list_head dq_dirty;      /* List of dirty dquots */
        struct mutex dq_lock;           /* dquot IO lock */
+       spinlock_t dq_dqb_lock;         /* Lock protecting dq_dqb changes */
        atomic_t dq_count;              /* Use count */
        struct super_block *dq_sb;      /* superblock this applies to */
        struct kqid dq_id;              /* ID this applies to (uid, gid, projid) */
        loff_t dq_off;                  /* Offset of dquot on disk */
        unsigned long dq_flags;         /* See DQ_* */
        atomic_t dq_count;              /* Use count */
        struct super_block *dq_sb;      /* superblock this applies to */
        struct kqid dq_id;              /* ID this applies to (uid, gid, projid) */
        loff_t dq_off;                  /* Offset of dquot on disk */
        unsigned long dq_flags;         /* See DQ_* */
-       struct mem_dqblk dq_dqb;        /* Diskquota usage */
+       struct mem_dqblk dq_dqb;        /* Diskquota usage [dq_dqb_lock] */
 };
 
 /* Operations which must be implemented by each quota format */
 };
 
 /* Operations which must be implemented by each quota format */