[GFS2] Don't flush everything on fdatasync [70/70]

Steven Whitehouse
2006-11-30T12:24:42Z

>From 33c3de32872ef3c075e4dac04c0de8f86ac39f6f Mon Sep 17 00:00:00 2001
From: Steven Whitehouse <swhiteho@redhat.com>
Date: Thu, 30 Nov 2006 10:14:32 -0500
Subject: [PATCH] [GFS2] Don't flush everything on fdatasync

The gfs2_fsync() function was doing a journal flush on each
and every call. While this is correct, its also a lot of
overhead. This patch means that on fdatasync flushes we
rely on the VFS to flush the data for us and we don't do
a journal flush unless we really need to.

We have to do a journal flush for stuffed files though because
they have the data and the inode metadata in the same block.
Journaled files also need a journal flush too of course.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
---
fs/gfs2/ops_file.c | 30 +++++++++++++++++++++++++++---
1 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/fs/gfs2/ops_file.c b/fs/gfs2/ops_file.c
index c2be216..7bd971b 100644
--- a/fs/gfs2/ops_file.c
+++ b/fs/gfs2/ops_file.c
@@ -22,6 +22,7 @@ #include <linux/gfs2_ondisk.h>
#include <linux/ext2_fs.h>
#include <linux/crc32.h>
#include <linux/lm_interface.h>
+#include <linux/writeback.h>
#include <asm/uaccess.h>

#include "gfs2.h"
@@ -503,16 +504,39 @@ static int gfs2_close(struct inode *inod
* @file: the file that points to the dentry (we ignore this)
* @dentry: the dentry that points to the inode to sync
*
+ * The VFS will flush "normal" data for us. We only need to worry
+ * about metadata here. For journaled data, we just do a log flush
+ * as we can't avoid it. Otherwise we can just bale out if datasync
+ * is set. For stuffed inodes we must flush the log in order to
+ * ensure that all data is on disk.
+ *
* Returns: errno
*/

static int gfs2_fsync(struct file *file, struct dentry *dentry, int datasync)
{
- struct gfs2_inode *ip = GFS2_I(dentry->d_inode);
+ struct inode *inode = dentry->d_inode;
+ int sync_state = inode->i_state & (I_DIRTY_SYNC|I_DIRTY_DATASYNC);
+ int ret = 0;
+ struct writeback_control wbc = {
+ .sync_mode = WB_SYNC_ALL,
+ .nr_to_write = 0,
+ };
+
+ if (gfs2_is_jdata(GFS2_I(inode))) {
+ gfs2_log_flush(GFS2_SB(inode), GFS2_I(inode)->i_gl);
+ return 0;
+ }

- gfs2_log_flush(ip->i_gl->gl_sbd, ip->i_gl);
+ if (sync_state != 0) {
+ if (!datasync)
+ ret = sync_inode(inode, &wbc);

- return 0;
+ if (gfs2_is_stuffed(GFS2_I(inode)))
+ gfs2_log_flush(GFS2_SB(inode), GFS2_I(inode)->i_gl);
+ }
+
+ return ret;
}

/**
--
1.4.1