[PATCH 06/11] f2fs: skip unnecessary data writes during fsync

[Jaegeuk Kim <jaegeuk@kernel.org>]

This patch intends to improve the fsync performance by skipping remaining the
recovery information, only when there is no data that we should recover.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/file.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 7c652b3..121689a 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -133,6 +133,17 @@ int f2fs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
 		return ret;
 	}
 
+	/*
+	 * if there is no written data, don't waste time to write recovery info.
+	 */
+	if (!is_inode_flag_set(fi, FI_APPEND_WRITE) &&
+		!exist_written_data(sbi, inode->i_ino, APPEND_INO)) {
+		if (is_inode_flag_set(fi, FI_UPDATE_WRITE) &&
+			exist_written_data(sbi, inode->i_ino, UPDATE_INO))
+			goto flush_out;
+		goto out;
+	}
+
 	/* guarantee free sections for fsync */
 	f2fs_balance_fs(sbi);
 
@@ -188,6 +199,11 @@ int f2fs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
 		ret = wait_on_node_pages_writeback(sbi, inode->i_ino);
 		if (ret)
 			goto out;
+
+		/* once recovery info is written, don't need to tack this */
+		remove_dirty_inode(sbi, inode->i_ino, APPEND_INO);
+flush_out:
+		remove_dirty_inode(sbi, inode->i_ino, UPDATE_INO);
 		ret = f2fs_issue_flush(F2FS_SB(inode->i_sb));
 	}
 out:
-- 
1.8.5.2 (Apple Git-48)