linux-ext4 - Re: [PATCH 4/5] afs: Zero bytes after 'oldsize' if we're expanding the file

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Message-ID: <2730679.1677505767@warthog.procyon.org.uk>
Date:   Mon, 27 Feb 2023 13:49:27 +0000
From:   David Howells <dhowells@...hat.com>
To:     "Matthew Wilcox (Oracle)" <willy@...radead.org>
Cc:     dhowells@...hat.com, linux-fsdevel@...r.kernel.org,
        linux-afs@...ts.infradead.org, linux-btrfs@...r.kernel.org,
        linux-ext4@...r.kernel.org, linux-mm@...ck.org,
        Hugh Dickins <hughd@...gle.com>, linux-kernel@...r.kernel.org,
        fstests@...r.kernel.org
Subject: Re: [PATCH 4/5] afs: Zero bytes after 'oldsize' if we're expanding the file

Matthew Wilcox (Oracle) <willy@...radead.org> wrote:

> POSIX requires that "If the file size is increased, the extended area
> shall appear as if it were zero-filled".  It is possible to use mmap to
> write past EOF and that data will become visible instead of zeroes.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>

That seems to work.  Do you want me to pass it on to Linus?  If not:

Acked-by: David Howells <dhowells@...hat.com>