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Commit d755fb38 authored by Eric Sandeen's avatar Eric Sandeen Committed by Theodore Ts'o
Browse files

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: default avatarEric Sandeen <sandeen@redhat.com>
Signed-off-by: default avatarMingming Cao <cmm@us.ibm.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 654b4908

fs/ext4/fsync.c

+4 −0
Original line number Original line Diff line number Diff line
@@ -27,6 +27,7 @@ 
#include <linux/sched.h>

#include <linux/sched.h>

#include <linux/writeback.h>

#include <linux/writeback.h>

#include <linux/jbd2.h>

#include <linux/jbd2.h>

#include <linux/blkdev.h>

#include "ext4.h"

#include "ext4.h"

#include "ext4_jbd2.h"

#include "ext4_jbd2.h"
@@ -45,6 +46,7 @@ 
int ext4_sync_file(struct file * file, struct dentry *dentry, int datasync)

int ext4_sync_file(struct file * file, struct dentry *dentry, int datasync)

{

{

	struct inode *inode = dentry->d_inode;

	struct inode *inode = dentry->d_inode;

	journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;

	int ret = 0;

	int ret = 0;





	J_ASSERT(ext4_journal_current_handle() == NULL);

	J_ASSERT(ext4_journal_current_handle() == NULL);
@@ -85,6 +87,8 @@ int ext4_sync_file(struct file * file, struct dentry *dentry, int datasync) 
			.nr_to_write = 0, /* sys_fsync did this */

			.nr_to_write = 0, /* sys_fsync did this */

		};

		};

		ret = sync_inode(inode, &wbc);

		ret = sync_inode(inode, &wbc);

		if (journal && (journal->j_flags & JBD2_BARRIER))

			blkdev_issue_flush(inode->i_sb->s_bdev, NULL);

	}

	}

out:

out:

	return ret;

	return ret;