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From:   David Howells <dhowells@redhat.com>
In-Reply-To: <20220110111444.926753-1-asmadeus@codewreck.org>
References: <20220110111444.926753-1-asmadeus@codewreck.org>
To:     Dominique Martinet <asmadeus@codewreck.org>
Cc:     dhowells@redhat.com, v9fs-developer@lists.sourceforge.net,
        linux-kernel@vger.kernel.org, lucho@ionkov.net, ericvh@gmail.com,
        stable@vger.kernel.org
Subject: Re: [PATCH] 9p: fix enodata when reading growing file
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Date:   Mon, 10 Jan 2022 11:18:42 +0000
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Dominique Martinet <asmadeus@codewreck.org> wrote:

> Reading from a file that was just extended by a write, but the write had
> not yet reached the server would return ENODATA as illustrated by this
> command:
> $ xfs_io -c 'open -ft test' -c 'w 4096 1000' -c 'r 0 1000'
> wrote 1000/1000 bytes at offset 4096
> 1000.000000 bytes, 1 ops; 0.0001 sec (5.610 MiB/sec and 5882.3529 ops/se=
c)
> pread: No data available
> =

> Fix this case by having netfs assume zeroes when reads from server come
> short like AFS and CEPH do
> =

> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
> Co-authored-by: David Howells <dhowells@redhat.com>
> Cc: stable@vger.kernel.org

I think you want this also:

Fixes: eb497943fa21 ("9p: Convert to using the netfs helper lib to do read=
s and caching")

Reviewed-by: David Howells <dhowells@redhat.com>