quota: provide interface for readding allocated space into reserved space

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>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

2 files changed, 55 insertions, 2 deletions

diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index fbad622841f..9a702e19353 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 04ce1ac20d2..d0ea7ef75e2 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);
 }