[PATCH 7/8] f2fs: introduce new option for controlling data flush

[Chao Yu <chao2.yu@samsung.com>]

Add a new option 'data_flush' to enable/disable data flush functionality
in checkpoint.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
---
 Documentation/filesystems/f2fs.txt | 2 ++
 fs/f2fs/checkpoint.c               | 2 +-
 fs/f2fs/f2fs.h                     | 1 +
 fs/f2fs/super.c                    | 7 +++++++
 4 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt
index 8088bd9..727373e 100644
--- a/Documentation/filesystems/f2fs.txt
+++ b/Documentation/filesystems/f2fs.txt
@@ -151,6 +151,8 @@ noextent_cache         Disable an extent cache based on rb-tree explicitly, see
                        the above extent_cache mount option.
 noinline_data          Disable the inline data feature, inline data feature is
                        enabled by default.
+data_flush             Enable data flushing during checkpoint in order to
+                       persist data of regular and symlink.
 
 ================================================================================
 DEBUGFS ENTRIES
diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index a73909c..2fdf271 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -855,7 +855,7 @@ static int block_operations(struct f2fs_sb_info *sbi)
 
 retry_flush_datas:
 	/* write all the dirty data pages */
-	if (get_pages(sbi, F2FS_DIRTY_DATAS)) {
+	if (test_opt(sbi, DATA_FLUSH) && get_pages(sbi, F2FS_DIRTY_DATAS)) {
 		sync_dirty_inodes(sbi, FILE_INODE);
 		if (unlikely(f2fs_cp_error(sbi))) {
 			err = -EIO;
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 4d44732..ee1f0a8 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -54,6 +54,7 @@
 #define F2FS_MOUNT_FASTBOOT		0x00001000
 #define F2FS_MOUNT_EXTENT_CACHE		0x00002000
 #define F2FS_MOUNT_FORCE_FG_GC		0x00004000
+#define F2FS_MOUNT_DATA_FLUSH		0x00008000
 
 #define clear_opt(sbi, option)	(sbi->mount_opt.opt &= ~F2FS_MOUNT_##option)
 #define set_opt(sbi, option)	(sbi->mount_opt.opt |= F2FS_MOUNT_##option)
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 051bce6..694e092 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -67,6 +67,7 @@ enum {
 	Opt_extent_cache,
 	Opt_noextent_cache,
 	Opt_noinline_data,
+	Opt_data_flush,
 	Opt_nodiscard,
 	Opt_err,
 };
@@ -92,6 +93,7 @@ static match_table_t f2fs_tokens = {
 	{Opt_extent_cache, "extent_cache"},
 	{Opt_noextent_cache, "noextent_cache"},
 	{Opt_noinline_data, "noinline_data"},
+	{Opt_data_flush, "data_flush"},
 	{Opt_nodiscard, "nodiscard"},
 	{Opt_err, NULL},
 };
@@ -411,6 +413,9 @@ static int parse_options(struct super_block *sb, char *options)
 		case Opt_noinline_data:
 			clear_opt(sbi, INLINE_DATA);
 			break;
+		case Opt_data_flush:
+			clear_opt(sbi, DATA_FLUSH);
+			break;
 		default:
 			f2fs_msg(sb, KERN_ERR,
 				"Unrecognized mount option \"%s\" or missing value",
@@ -694,6 +699,8 @@ static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
 		seq_puts(seq, ",extent_cache");
 	else
 		seq_puts(seq, ",noextent_cache");
+	if (test_opt(sbi, DATA_FLUSH))
+		seq_puts(seq, ",data_flush");
 	seq_printf(seq, ",active_logs=%u", sbi->active_logs);
 
 	return 0;
-- 
2.6.3