f2fs: introduce a flag to represent each nat entry information

This patch introduces a flag in the nat entry structure to merge various
information such as checkpointed and fsync_done marks.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/node.c

@@ -131,7 +131,7 @@ int is_checkpointed_node(struct f2fs_sb_info *sbi, nid_t nid)
 
 	read_lock(&nm_i->nat_tree_lock);
 	e = __lookup_nat_cache(nm_i, nid);
-	if (e && !e->checkpointed)
+	if (e && !get_nat_flag(e, IS_CHECKPOINTED))
 		is_cp = 0;
 	read_unlock(&nm_i->nat_tree_lock);
 	return is_cp;
@@ -146,7 +146,7 @@ bool fsync_mark_done(struct f2fs_sb_info *sbi, nid_t nid)
 	read_lock(&nm_i->nat_tree_lock);
 	e = __lookup_nat_cache(nm_i, nid);
 	if (e)
-		fsync_done = e->fsync_done;
+		fsync_done = get_nat_flag(e, HAS_FSYNC_MARK);
 	read_unlock(&nm_i->nat_tree_lock);
 	return fsync_done;
 }
@@ -159,7 +159,7 @@ void fsync_mark_clear(struct f2fs_sb_info *sbi, nid_t nid)
 	write_lock(&nm_i->nat_tree_lock);
 	e = __lookup_nat_cache(nm_i, nid);
 	if (e)
-		e->fsync_done = false;
+		set_nat_flag(e, HAS_FSYNC_MARK, false);
 	write_unlock(&nm_i->nat_tree_lock);
 }
 
@@ -176,7 +176,7 @@ static struct nat_entry *grab_nat_entry(struct f2fs_nm_info *nm_i, nid_t nid)
 	}
 	memset(new, 0, sizeof(struct nat_entry));
 	nat_set_nid(new, nid);
-	new->checkpointed = true;
+	set_nat_flag(new, IS_CHECKPOINTED, true);
 	list_add_tail(&new->list, &nm_i->nat_entries);
 	nm_i->nat_cnt++;
 	return new;
@@ -249,7 +249,7 @@ static void set_node_addr(struct f2fs_sb_info *sbi, struct node_info *ni,
 	/* update fsync_mark if its inode nat entry is still alive */
 	e = __lookup_nat_cache(nm_i, ni->ino);
 	if (e)
-		e->fsync_done = fsync_done;
+		set_nat_flag(e, HAS_FSYNC_MARK, fsync_done);
 	write_unlock(&nm_i->nat_tree_lock);
 }
 
@@ -1349,7 +1349,8 @@ static int add_free_nid(struct f2fs_sb_info *sbi, nid_t nid, bool build)
 		read_lock(&nm_i->nat_tree_lock);
 		ne = __lookup_nat_cache(nm_i, nid);
 		if (ne &&
-			(!ne->checkpointed || nat_get_blkaddr(ne) != NULL_ADDR))
+			(!get_nat_flag(ne, IS_CHECKPOINTED) ||
+				nat_get_blkaddr(ne) != NULL_ADDR))
 			allocated = true;
 		read_unlock(&nm_i->nat_tree_lock);
 		if (allocated)

fs/f2fs/node.h

@@ -39,10 +39,14 @@ struct node_info {
 	unsigned char version;	/* version of the node */
 };
 
+enum {
+	IS_CHECKPOINTED,	/* is it checkpointed before? */
+	HAS_FSYNC_MARK,		/* has the latest node fsync mark? */
+};
+
 struct nat_entry {
 	struct list_head list;	/* for clean or dirty nat list */
-	bool checkpointed;	/* whether it is checkpointed or not */
-	bool fsync_done;	/* whether the latest node has fsync mark */
+	unsigned char flag;	/* for node information bits */
 	struct node_info ni;	/* in-memory node information */
 };
 
@@ -57,16 +61,32 @@ struct nat_entry {
 
 #define __set_nat_cache_dirty(nm_i, ne)					\
 	do {								\
-		ne->checkpointed = false;				\
+		set_nat_flag(ne, IS_CHECKPOINTED, false);		\
 		list_move_tail(&ne->list, &nm_i->dirty_nat_entries);	\
 	} while (0)
 #define __clear_nat_cache_dirty(nm_i, ne)				\
 	do {								\
-		ne->checkpointed = true;				\
+		set_nat_flag(ne, IS_CHECKPOINTED, true);		\
 		list_move_tail(&ne->list, &nm_i->nat_entries);		\
 	} while (0)
 #define inc_node_version(version)	(++version)
 
+static inline void set_nat_flag(struct nat_entry *ne,
+				unsigned int type, bool set)
+{
+	unsigned char mask = 0x01 << type;
+	if (set)
+		ne->flag |= mask;
+	else
+		ne->flag &= ~mask;
+}
+
+static inline bool get_nat_flag(struct nat_entry *ne, unsigned int type)
+{
+	unsigned char mask = 0x01 << type;
+	return ne->flag & mask;
+}
+
 static inline void node_info_from_raw_nat(struct node_info *ni,
 						struct f2fs_nat_entry *raw_ne)
 {