quota: Add quota reservation claim and released operations

Reserved quota will be claimed at the block allocation time. Over-booked
quota could be returned back with the release callback function.

Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: Jan Kara <jack@suse.cz>

3 files changed, 165 insertions, 4 deletions

diff --git a/fs/dquot.c b/fs/dquot.c
index 9b1c4d3c9d83..2916f91ca40c 100644
--- a/fs/dquot.c
+++ b/fs/dquot.c
@@ -904,6 +904,23 @@ static inline void dquot_resv_space(struct dquot *dquot, qsize_t number)
         dquot->dq_dqb.dqb_rsvspace += number;
 }
 
+/*
+ * Claim reserved quota space
+ */
+static void dquot_claim_reserved_space(struct dquot *dquot,
+                                                qsize_t number)
+{
+        WARN_ON(dquot->dq_dqb.dqb_rsvspace < number);
+        dquot->dq_dqb.dqb_curspace += number;
+        dquot->dq_dqb.dqb_rsvspace -= number;
+}
+
+static inline
+void dquot_free_reserved_space(struct dquot *dquot, qsize_t number)
+{
+        dquot->dq_dqb.dqb_rsvspace -= number;
+}
+
 static inline void dquot_decr_inodes(struct dquot *dquot, qsize_t number)
 {
         if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NEGATIVE_USAGE ||
@@ -1452,6 +1469,72 @@ warn_put_all:
         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);
+                goto out;
+        }
+
+        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);
+                goto out;
+        }
+
+        spin_lock(&dq_data_lock);
+        /* Claim reserved quotas to allocated quotas */
+        for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
+                if (inode->i_dquot[cnt] != NODQUOT)
+                        dquot_claim_reserved_space(inode->i_dquot[cnt],
+                                                        number);
+        }
+        /* Update inode bytes */
+        inode_add_bytes(inode, number);
+        spin_unlock(&dq_data_lock);
+        /* 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);
+out:
+        return ret;
+}
+EXPORT_SYMBOL(dquot_claim_space);
+
+/*
+ * Release reserved quota space
+ */
+void dquot_release_reserved_space(struct inode *inode, qsize_t number)
+{
+        int cnt;
+
+        if (IS_NOQUOTA(inode))
+                goto out;
+
+        down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
+        if (IS_NOQUOTA(inode))
+                goto out_unlock;
+
+        spin_lock(&dq_data_lock);
+        /* Release reserved dquots */
+        for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
+                if (inode->i_dquot[cnt] != NODQUOT)
+                        dquot_free_reserved_space(inode->i_dquot[cnt], number);
+        }
+        spin_unlock(&dq_data_lock);
+
+out_unlock:
+        up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
+out:
+        return;
+}
+EXPORT_SYMBOL(dquot_release_reserved_space);
+
 /*
  * This operation can block, but only after everything is updated
  */
@@ -1529,6 +1612,19 @@ int dquot_free_inode(const struct inode *inode, qsize_t number)
 }
 
 /*
+ * call back function, get reserved quota space from underlying fs
+ */
+qsize_t dquot_get_reserved_space(struct inode *inode)
+{
+        qsize_t reserved_space = 0;
+
+        if (sb_any_quota_active(inode->i_sb) &&
+            inode->i_sb->dq_op->get_reserved_space)
+                reserved_space = inode->i_sb->dq_op->get_reserved_space(inode);
+        return reserved_space;
+}
+
+/*
  * Transfer the number of inode and blocks from one diskquota to an other.
  *
  * This operation can block, but only after everything is updated
@@ -1536,7 +1632,8 @@ int dquot_free_inode(const struct inode *inode, qsize_t number)
  */
 int dquot_transfer(struct inode *inode, struct iattr *iattr)
 {
-        qsize_t space;
+        qsize_t space, cur_space;
+        qsize_t rsv_space = 0;
         struct dquot *transfer_from[MAXQUOTAS];
         struct dquot *transfer_to[MAXQUOTAS];
         int cnt, ret = QUOTA_OK;
@@ -1575,7 +1672,9 @@ int dquot_transfer(struct inode *inode, struct iattr *iattr)
                 goto put_all;
         }
         spin_lock(&dq_data_lock);
-        space = inode_get_bytes(inode);
+        cur_space = inode_get_bytes(inode);
+        rsv_space = dquot_get_reserved_space(inode);
+        space = cur_space + rsv_space;
         /* Build the transfer_from list and check the limits */
         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
                 if (transfer_to[cnt] == NODQUOT)
@@ -1604,11 +1703,14 @@ int dquot_transfer(struct inode *inode, struct iattr *iattr)
                         warntype_from_space[cnt] =
                                 info_bdq_free(transfer_from[cnt], space);
                         dquot_decr_inodes(transfer_from[cnt], 1);
-                        dquot_decr_space(transfer_from[cnt], space);
+                        dquot_decr_space(transfer_from[cnt], cur_space);
+                        dquot_free_reserved_space(transfer_from[cnt],
+                                                  rsv_space);
                 }
 
                 dquot_incr_inodes(transfer_to[cnt], 1);
-                dquot_incr_space(transfer_to[cnt], space);
+                dquot_incr_space(transfer_to[cnt], cur_space);
+                dquot_resv_space(transfer_to[cnt], rsv_space);
 
                 inode->i_dquot[cnt] = transfer_to[cnt];
         }
diff --git a/include/linux/quota.h b/include/linux/quota.h
index 54b837fa64f2..a510d91561f4 100644
--- a/include/linux/quota.h
+++ b/include/linux/quota.h
@@ -311,6 +311,12 @@ struct dquot_operations {
         int (*write_info) (struct super_block *, int);  /* Write of quota "superblock" */
         /* reserve quota for delayed block allocation */
         int (*reserve_space) (struct inode *, qsize_t, int);
+        /* claim reserved quota for delayed alloc */
+        int (*claim_space) (struct inode *, qsize_t);
+        /* release rsved quota for delayed alloc */
+        void (*release_rsv) (struct inode *, qsize_t);
+        /* get reserved quota for delayed alloc */
+        qsize_t (*get_reserved_space) (struct inode *);
 };
 
 /* Operations handling requests from userspace */
diff --git a/include/linux/quotaops.h b/include/linux/quotaops.h
index 3e3a0d2874d9..7369d04e0a86 100644
--- a/include/linux/quotaops.h
+++ b/include/linux/quotaops.h
@@ -35,6 +35,11 @@ void dquot_destroy(struct dquot *dquot);
 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);
+qsize_t dquot_get_reserved_space(struct inode *inode);
+
 int dquot_free_space(struct inode *inode, qsize_t number);
 int dquot_free_inode(const struct inode *inode, qsize_t number);
 
@@ -203,6 +208,31 @@ static inline int vfs_dq_alloc_inode(struct inode *inode)
         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))
@@ -354,6 +384,17 @@ static inline int vfs_dq_reserve_space(struct inode *inode, qsize_t nr)
         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);
@@ -397,6 +438,18 @@ static inline int vfs_dq_reserve_block(struct inode *inode, qsize_t nr)
                         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_block(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);