[Ocfs2-devel] [PATCH] Remove filesize checks for sync I/O journal commit

[Xue jiufei]

Hi Goldwyn,
On 2014/11/4 23:52, Goldwyn Rodrigues wrote:
> Filesize is not a good indication that the file needs to be synced.
> An example where this breaks is:
>  1. Open the file in O_SYNC|O_RDWR
>  2. Read a small portion of the file (say 64 bytes)
>  3. Lseek to starting of the file
>  4. Write 64 bytes
> 
> If the node crashes, it is not written out to disk because this
> was not committed in the journal and the other node which reads
> the file after recovery reads stale data (even if the write on
> the other node was successful)
> 
I have a question that if user open the file with O_SYNC,
it will call filemap_fdatawait_range() after generic_perform_write()
to wait until data reaches the disk, why another node may read the
stale data?

Thanks,
Xuejiufei

> --- 
> diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
> index 324dc93..69fb9f7 100644
> --- a/fs/ocfs2/file.c
> +++ b/fs/ocfs2/file.c
> @@ -2381,9 +2381,7 @@ out_dio:
>  		if (ret < 0)
>  			written = ret;
>  
> -		if (!ret && ((old_size != i_size_read(inode)) ||
> -			     (old_clusters != OCFS2_I(inode)->ip_clusters) ||
> -			     has_refcount)) {
> +		if (!ret) {
>  			ret = jbd2_journal_force_commit(osb->journal->j_journal);
>  			if (ret < 0)
>  				written = ret;
> 
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