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Date: Sun, 24 Sep 2017 01:32:03 -0700
From: Matthew Wilcox <willy@infradead.org>
To: Goldwyn Rodrigues <rgoldwyn@suse.de>
Cc: linux-fsdevel@vger.kernel.org,
        Goldwyn Rodrigues <rgoldwyn@suse.com>
Subject: Re: [PATCH] Return bytes transfered for partial direct I/O
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On Sat, Sep 23, 2017 at 06:10:14PM -0500, Goldwyn Rodrigues wrote:
> In case direct I/O encounters an error midway, it returns the error.
> Instead it should be returning the number of bytes transferred so far.
> 
> Test case (with ENOSPC):
> 1. Create an almost full filesystem
> 2. Create a file, say /mnt/lastfile, until the filesystem is full.
> 3. Direct write() with count > sizeof /mnt/lastfile.
> 
> Result: write() returns -ENOSPC. However, file content has data written
> in step 3.

Can you add an xfstest to be sure we don't regress this in the future?