Re: exofs_file_fsync

[Boaz Harrosh <bharrosh@panasas.com>]

On 05/31/2010 01:33 PM, Christoph Hellwig wrote:
> On Mon, May 31, 2010 at 01:31:01PM +0300, Boaz Harrosh wrote:
>> OK, I was just looking at that. thanks you saved me some digging.
>> should I just open-code the generic_file_fsync minus the blocks
>> thing then?
> 
> sync_mapping_buffers is a no-op for you so you can keep it.
> The other difference is that you sync out the superblock at the
> end of your fsync implementation.  That is rather unusual, but I don't
> know enough about exofs if you really need to update data in the
> superblock to commit file data to disk.
> 
>> I'm busy with the truncate stuff, but I'll do this next.
>> Do you need this ASAP?
> 
> I just noticed it while walking through the fsync implementations.
> 

OK Chritoff I would need your help Please.

It looks like what I need exactly is:
	write_inode_now(inode, sync)

But write_inode_now() has one extra hunk over generic_file_fsync:
	if (sync)
		inode_sync_wait(inode);

Do you think I can get in trouble calling it from ->fsync

I don't like generic_file_fsync because it does not write my
data since I don't have buffer_heads.

OK, I'm totally lost what does ->fsync need to do? only write
the inode or the pages as well?

Boaz
---
git diff --stat -p -M fs/exofs/file.c
 fs/exofs/file.c |    8 ++------
 1 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/fs/exofs/file.c b/fs/exofs/file.c
index f9bfe2b..9b3555e 100644
--- a/fs/exofs/file.c
+++ b/fs/exofs/file.c
@@ -47,18 +47,14 @@ static int exofs_file_fsync(struct file *filp, int datasync)
 	struct inode *inode = mapping->host;
 	struct super_block *sb;
 
-	ret = filemap_write_and_wait(mapping);
-	if (ret)
-		return ret;
-
 	/* sync the inode attributes */
-	ret = write_inode_now(inode, 1);
+	ret = write_inode_now(inode, datasync);
 
 	/* This is a good place to write the sb */
 	/* TODO: Sechedule an sb-sync on create */
 	sb = inode->i_sb;
 	if (sb->s_dirt)
-		exofs_sync_fs(sb, 1);
+		exofs_sync_fs(sb, datasync);
 
 	return ret;
 }