diff -puN fs/dquot.c~quota-add-quota-claim-and-release-reserved-quota-blocks-operations fs/dquot.c
--- a/fs/dquot.c~quota-add-quota-claim-and-release-reserved-quota-blocks-operations
+++ a/fs/dquot.c
@@ -846,6 +846,24 @@ static inline void dquot_resv_space(stru
 	dquot->dq_dqb.dqb_rsvspace += number;
 }
 
+/*
+ * Claim reserved quota space
+ */
+static int dquot_claim_reserved_space(struct dquot *dquot,
+						qsize_t number)
+{
+	if (dquot->dq_dqb.dqb_rsvspace < number) {
+		printk(KERN_WARNING "Reserved quota %llu is not enough for"
+			"request %llu bytes\n",
+			(unsigned long long)dquot->dq_dqb.dqb_rsvspace, number);
+		return 1;
+	}
+
+	dquot->dq_dqb.dqb_curspace += number;
+	dquot->dq_dqb.dqb_rsvspace -= number;
+	return 0;
+}
+
 static inline void dquot_decr_inodes(struct dquot *dquot, qsize_t number)
 {
 	if (dquot->dq_dqb.dqb_curinodes > number)
@@ -1319,6 +1337,73 @@ out:
 	return ret;
 }
 
+int dquot_claim_space(struct inode *inode, qsize_t number)
+{
+	int cnt;
+	int ret = QUOTA_OK;
+
+	if (IS_NOQUOTA(inode)) {
+		inode_add_bytes(inode, number);
+		return ret;
+	}
+
+	down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
+	if (IS_NOQUOTA(inode))	{
+		up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
+		inode_add_bytes(inode, number);
+		return ret;
+	}
+
+	/* Claim reserved quotas to allocated quotas */
+	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
+		if (inode->i_dquot[cnt] != NODQUOT)
+			ret = dquot_claim_reserved_space(inode->i_dquot[cnt],
+							number);
+	}
+	if (ret == NO_QUOTA) {
+		up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
+		return ret;
+	}
+	/* Dirtify all the dquots - this can block when journalling */
+	for (cnt = 0; cnt < MAXQUOTAS; cnt++)
+		if (inode->i_dquot[cnt])
+			mark_dquot_dirty(inode->i_dquot[cnt]);
+	up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
+
+	/* Update inode bytes */
+	inode_add_bytes(inode, number);
+	return ret;
+}
+
+/*
+ * Release reserved quota space
+ */
+void dquot_release_reserved_space(struct inode *inode, qsize_t number)
+{
+	int cnt;
+	struct dquot *dquot;
+
+	if (IS_NOQUOTA(inode))
+		goto out;
+
+	down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
+	if (IS_NOQUOTA(inode))
+		goto out_unlock;
+
+	/* Release reserved dquots */
+	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
+		if (inode->i_dquot[cnt] != NODQUOT) {
+			dquot = inode->i_dquot[cnt];
+			dquot->dq_dqb.dqb_rsvspace -= number;
+		}
+	}
+
+out_unlock:
+	up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
+out:
+	return;
+}
+
 /*
  * This operation can block, but only after everything is updated
  */
@@ -2344,6 +2429,8 @@ EXPORT_SYMBOL(dquot_alloc_inode);
 EXPORT_SYMBOL(dquot_free_space);
 EXPORT_SYMBOL(dquot_free_inode);
 EXPORT_SYMBOL(dquot_reserve_space);
+EXPORT_SYMBOL(dquot_claim_space);
+EXPORT_SYMBOL(dquot_release_reserved_space);
 EXPORT_SYMBOL(dquot_transfer);
 EXPORT_SYMBOL(vfs_dq_transfer);
 EXPORT_SYMBOL(vfs_dq_quota_on_remount);
diff -puN include/linux/quota.h~quota-add-quota-claim-and-release-reserved-quota-blocks-operations include/linux/quota.h
--- a/include/linux/quota.h~quota-add-quota-claim-and-release-reserved-quota-blocks-operations
+++ a/include/linux/quota.h
@@ -292,7 +292,9 @@ struct dquot_operations {
 	int (*release_dquot) (struct dquot *);		/* Quota is going to be deleted from disk */
 	int (*mark_dirty) (struct dquot *);		/* Dquot is marked dirty */
 	int (*write_info) (struct super_block *, int);	/* Write of quota "superblock" */
-	int (*reserve_space) (struct inode *, qsize_t, int); /* reserve quota for delayed block allocation */
+	int (*reserve_space) (struct inode *, qsize_t, int); /* reserve quota for delayed alloc */
+	int (*claim_space) (struct inode *, qsize_t); /* claim reserved quota for delayed alloc */
+	void (*release_rsv) (struct inode *, qsize_t); /* release rsved quota for delayed alloc */
 };
 
 /* Operations handling requests from userspace */
diff -puN include/linux/quotaops.h~quota-add-quota-claim-and-release-reserved-quota-blocks-operations include/linux/quotaops.h
--- a/include/linux/quotaops.h~quota-add-quota-claim-and-release-reserved-quota-blocks-operations
+++ a/include/linux/quotaops.h
@@ -28,6 +28,11 @@ int dquot_drop(struct inode *inode);
 int dquot_alloc_space(struct inode *inode, qsize_t number, int prealloc);
 int dquot_alloc_inode(const struct inode *inode, qsize_t number);
 
+int dquot_reserve_space(struct inode *inode, qsize_t number, int prealloc);
+int dquot_claim_space(struct inode *inode, qsize_t number);
+void dquot_release_reserved_space(struct inode *inode, qsize_t number);
+
+
 int dquot_free_space(struct inode *inode, qsize_t number);
 int dquot_free_inode(const struct inode *inode, qsize_t number);
 
@@ -196,6 +201,31 @@ static inline int vfs_dq_alloc_inode(str
 	return 0;
 }
 
+/*
+ * Convert in-memory reserved quotas to real consumed quotas
+ */
+static inline int vfs_dq_claim_space(struct inode *inode, qsize_t nr)
+{
+	if (sb_any_quota_active(inode->i_sb)) {
+		if (inode->i_sb->dq_op->claim_space(inode, nr) == NO_QUOTA)
+			return 1;
+	} else
+		inode_add_bytes(inode, nr);
+
+	mark_inode_dirty(inode);
+	return 0;
+}
+
+/*
+ * Release reserved (in-memory) quotas
+ */
+static inline
+void vfs_dq_release_reservation_space(struct inode *inode, qsize_t nr)
+{
+	if (sb_any_quota_active(inode->i_sb))
+		inode->i_sb->dq_op->release_rsv(inode, nr);
+}
+
 static inline void vfs_dq_free_space_nodirty(struct inode *inode, qsize_t nr)
 {
 	if (sb_any_quota_active(inode->i_sb))
@@ -347,6 +377,17 @@ static inline int vfs_dq_reserve_space(s
 	return 0;
 }
 
+static inline int vfs_dq_claim_space(struct inode *inode, qsize_t nr)
+{
+	return vfs_dq_alloc_space(inode, nr);
+}
+
+static inline
+int vfs_dq_release_reservation_space(struct inode *inode, qsize_t nr)
+{
+	return 0;
+}
+
 static inline void vfs_dq_free_space_nodirty(struct inode *inode, qsize_t nr)
 {
 	inode_sub_bytes(inode, nr);
@@ -391,6 +432,18 @@ static inline int vfs_dq_reserve_block(s
 			nr << inode->i_blkbits);
 }
 
+static inline int vfs_dq_claim_block(struct inode *inode, qsize_t nr)
+{
+	return vfs_dq_claim_space(inode,
+			nr << inode->i_blkbits);
+}
+
+static inline
+void vfs_dq_release_reservation(struct inode *inode, qsize_t nr)
+{
+	vfs_dq_release_reservation_space(inode, nr << inode->i_blkbits);
+}
+
 static inline void vfs_dq_free_block_nodirty(struct inode *inode, qsize_t nr)
 {
 	vfs_dq_free_space_nodirty(inode, nr << inode->i_sb->s_blocksize_bits);
@@ -420,6 +473,8 @@ static inline void vfs_dq_free_block(str
 				vfs_dq_alloc_block_nodirty(inode, nr)
 #define DQUOT_ALLOC_BLOCK(inode, nr) vfs_dq_alloc_block(inode, nr)
 #define DQUOT_RESERVE_BLOCK(inode, nr) vfs_dq_reserve_block(inode, nr)
+#define DQUOT_CLAIM_BLOCK(inode, nr) vfs_dq_claim_block(inode, nr)
+#define DQUOT_RELEASE_RSV_BLOCK(inode, nr) vfs_dq_release_reservation(inode, nr)
 #define DQUOT_ALLOC_INODE(inode) vfs_dq_alloc_inode(inode)
 #define DQUOT_FREE_SPACE_NODIRTY(inode, nr) \
 				vfs_dq_free_space_nodirty(inode, nr)
