[PATCH 1/2] quota: Provide interface for readding allocated space into reserved space

[Jan Kara <jack@suse.cz>]

ext4 needs to convert allocated (metadata) blocks back into blocks
reserved for delayed allocation. Add functions into quota code for
supporting such operation.

Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/quota/dquot.c         | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 fs/stat.c                | 11 +++++++++--
 include/linux/fs.h       |  1 +
 include/linux/quotaops.h | 15 +++++++++++++++
 4 files changed, 71 insertions(+), 2 deletions(-)

 The ext4 patch depends on this so Ted please take it via ext4 tree. Thanks.

diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index fbad622..9a702e1 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -1094,6 +1094,14 @@ static void dquot_claim_reserved_space(struct dquot *dquot, qsize_t number)
 	dquot->dq_dqb.dqb_rsvspace -= number;
 }
 
+static void dquot_reclaim_reserved_space(struct dquot *dquot, qsize_t 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;
+}
+
 static inline
 void dquot_free_reserved_space(struct dquot *dquot, qsize_t number)
 {
@@ -1528,6 +1536,15 @@ void inode_claim_rsv_space(struct inode *inode, qsize_t number)
 }
 EXPORT_SYMBOL(inode_claim_rsv_space);
 
+void inode_reclaim_rsv_space(struct inode *inode, qsize_t number)
+{
+	spin_lock(&inode->i_lock);
+	*inode_reserved_space(inode) += number;
+	__inode_sub_bytes(inode, number);
+	spin_unlock(&inode->i_lock);
+}
+EXPORT_SYMBOL(inode_reclaim_rsv_space);
+
 void inode_sub_rsv_space(struct inode *inode, qsize_t number)
 {
 	spin_lock(&inode->i_lock);
@@ -1702,6 +1719,35 @@ int dquot_claim_space_nodirty(struct inode *inode, qsize_t number)
 EXPORT_SYMBOL(dquot_claim_space_nodirty);
 
 /*
+ * Convert allocated space back to in-memory reserved quotas
+ */
+void dquot_reclaim_space_nodirty(struct inode *inode, qsize_t number)
+{
+	int cnt;
+
+	if (!dquot_active(inode)) {
+		inode_reclaim_rsv_space(inode, number);
+		return;
+	}
+
+	down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
+	spin_lock(&dq_data_lock);
+	/* Claim reserved quotas to allocated quotas */
+	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
+		if (inode->i_dquot[cnt])
+			dquot_reclaim_reserved_space(inode->i_dquot[cnt],
+						     number);
+	}
+	/* Update inode bytes */
+	inode_reclaim_rsv_space(inode, number);
+	spin_unlock(&dq_data_lock);
+	mark_all_dquot_dirty(inode->i_dquot);
+	up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
+	return;
+}
+EXPORT_SYMBOL(dquot_reclaim_space_nodirty);
+
+/*
  * This operation can block, but only after everything is updated
  */
 void __dquot_free_space(struct inode *inode, qsize_t number, int flags)
diff --git a/fs/stat.c b/fs/stat.c
index 04ce1ac..d0ea7ef 100644
--- a/fs/stat.c
+++ b/fs/stat.c
@@ -447,9 +447,8 @@ void inode_add_bytes(struct inode *inode, loff_t bytes)
 
 EXPORT_SYMBOL(inode_add_bytes);
 
-void inode_sub_bytes(struct inode *inode, loff_t bytes)
+void __inode_sub_bytes(struct inode *inode, loff_t bytes)
 {
-	spin_lock(&inode->i_lock);
 	inode->i_blocks -= bytes >> 9;
 	bytes &= 511;
 	if (inode->i_bytes < bytes) {
@@ -457,6 +456,14 @@ void inode_sub_bytes(struct inode *inode, loff_t bytes)
 		inode->i_bytes += 512;
 	}
 	inode->i_bytes -= bytes;
+}
+
+EXPORT_SYMBOL(__inode_sub_bytes);
+
+void inode_sub_bytes(struct inode *inode, loff_t bytes)
+{
+	spin_lock(&inode->i_lock);
+	__inode_sub_bytes(inode, bytes);
 	spin_unlock(&inode->i_lock);
 }
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 9818747..e789352 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2503,6 +2503,7 @@ extern void generic_fillattr(struct inode *, struct kstat *);
 extern int vfs_getattr(struct path *, struct kstat *);
 void __inode_add_bytes(struct inode *inode, loff_t bytes);
 void inode_add_bytes(struct inode *inode, loff_t bytes);
+void __inode_sub_bytes(struct inode *inode, loff_t bytes);
 void inode_sub_bytes(struct inode *inode, loff_t bytes);
 loff_t inode_get_bytes(struct inode *inode);
 void inode_set_bytes(struct inode *inode, loff_t bytes);
diff --git a/include/linux/quotaops.h b/include/linux/quotaops.h
index 1c50093..6965fe3 100644
--- a/include/linux/quotaops.h
+++ b/include/linux/quotaops.h
@@ -41,6 +41,7 @@ void __quota_error(struct super_block *sb, const char *func,
 void inode_add_rsv_space(struct inode *inode, qsize_t number);
 void inode_claim_rsv_space(struct inode *inode, qsize_t number);
 void inode_sub_rsv_space(struct inode *inode, qsize_t number);
+void inode_reclaim_rsv_space(struct inode *inode, qsize_t number);
 
 void dquot_initialize(struct inode *inode);
 void dquot_drop(struct inode *inode);
@@ -59,6 +60,7 @@ int dquot_alloc_inode(const struct inode *inode);
 
 int dquot_claim_space_nodirty(struct inode *inode, qsize_t number);
 void dquot_free_inode(const struct inode *inode);
+void dquot_reclaim_space_nodirty(struct inode *inode, qsize_t number);
 
 int dquot_disable(struct super_block *sb, int type, unsigned int flags);
 /* Suspend quotas on remount RO */
@@ -238,6 +240,13 @@ static inline int dquot_claim_space_nodirty(struct inode *inode, qsize_t number)
 	return 0;
 }
 
+static inline int dquot_reclaim_space_nodirty(struct inode *inode,
+					      qsize_t number)
+{
+	inode_sub_bytes(inode, number);
+	return 0;
+}
+
 static inline int dquot_disable(struct super_block *sb, int type,
 		unsigned int flags)
 {
@@ -336,6 +345,12 @@ static inline int dquot_claim_block(struct inode *inode, qsize_t nr)
 	return ret;
 }
 
+static inline void dquot_reclaim_block(struct inode *inode, qsize_t nr)
+{
+	dquot_reclaim_space_nodirty(inode, nr << inode->i_blkbits);
+	mark_inode_dirty_sync(inode);
+}
+
 static inline void dquot_free_space_nodirty(struct inode *inode, qsize_t nr)
 {
 	__dquot_free_space(inode, nr, 0);
-- 
1.8.1.4