ext4: call blkdev_issue_flush on fsync
To ensure that bits are truly on-disk after an fsync,
we should call blkdev_issue_flush if barriers are supported.
Inspired by an old thread on barriers, by reiserfs & xfs
which do the same, and by a patch SuSE ships with their kernel
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c
index 1c8ba48..a45c373 100644
--- a/fs/ext4/fsync.c
+++ b/fs/ext4/fsync.c
@@ -27,6 +27,7 @@
#include <linux/sched.h>
#include <linux/writeback.h>
#include <linux/jbd2.h>
+#include <linux/blkdev.h>
#include "ext4.h"
#include "ext4_jbd2.h"
@@ -45,6 +46,7 @@
int ext4_sync_file(struct file * file, struct dentry *dentry, int datasync)
{
struct inode *inode = dentry->d_inode;
+ journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
int ret = 0;
J_ASSERT(ext4_journal_current_handle() == NULL);
@@ -85,6 +87,8 @@
.nr_to_write = 0, /* sys_fsync did this */
};
ret = sync_inode(inode, &wbc);
+ if (journal && (journal->j_flags & JBD2_BARRIER))
+ blkdev_issue_flush(inode->i_sb->s_bdev, NULL);
}
out:
return ret;