[Ocfs2-devel] [PATCH 1/2] ocfs2: Flush drive's caches on fdatasync

[Jan Kara]

We have to issue a cache flush during fdatasync even if inode doesn't have
I_DIRTY_DATASYNC set because we still have to get written *data* to disk to
observe fdatasync() guarantees.

Signed-off-by: Jan Kara <jack at suse.cz>
---
 fs/ocfs2/file.c |   10 +++++++++-
 1 files changed, 9 insertions(+), 1 deletions(-)

diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 2b10b36..5659d85 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -36,6 +36,7 @@
 #include <linux/writeback.h>
 #include <linux/falloc.h>
 #include <linux/quotaops.h>
+#include <linux/blkdev.h>
 
 #define MLOG_MASK_PREFIX ML_INODE
 #include <cluster/masklog.h>
@@ -190,8 +191,15 @@ static int ocfs2_sync_file(struct file *file, int datasync)
 	if (err)
 		goto bail;
 
-	if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
+	if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) {
+		/*
+		 * Although inode doesn't need writing, we still have to flush
+		 * drive's caches to get data to the platter
+		 */
+		blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL,
+				   BLKDEV_IFL_WAIT);
 		goto bail;
+	}
 
 	journal = osb->journal->j_journal;
 	err = jbd2_journal_force_commit(journal);
-- 
1.6.4.2