Re: [PATCH] ext4: fix cache flish in ext4_sync_file

[Eric Sandeen <sandeen@redhat.com>]

Christoph Hellwig wrote:
> We need to flush the write cache unconditionally in ->fsync, otherwise
> writes into already allocated blocks can get lost.  Writes into fully
> allocated files are very common when using disk images for
> virtualization, and without this fix can easily lose data after
> an fdatasync, which is the typical implementation for a cache flush on
> the virtual drive.
> 
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Fixing my old commit, I guess ;)

Seems right to me

Acked-by: Eric Sandeen <sandeen@redhat.com>


> Index: linux-2.6/fs/ext4/fsync.c
> ===================================================================
> --- linux-2.6.orig/fs/ext4/fsync.c
> +++ linux-2.6/fs/ext4/fsync.c
> @@ -92,9 +92,9 @@ int ext4_sync_file(struct file *file, st
>  			.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:
> +	if (journal && (journal->j_flags & JBD2_BARRIER))
> +		blkdev_issue_flush(inode->i_sb->s_bdev, NULL);
>  	return ret;
>  }
> --
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