linux-kernel - Re: [PATCH] 9p: fix enodata when reading growing file

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Message-ID: <3730531.1641813522@warthog.procyon.org.uk>
Date:   Mon, 10 Jan 2022 11:18:42 +0000
From:   David Howells <dhowells@...hat.com>
To:     Dominique Martinet <asmadeus@...ewreck.org>
Cc:     dhowells@...hat.com, v9fs-developer@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org, lucho@...kov.net, ericvh@...il.com,
        stable@...r.kernel.org
Subject: Re: [PATCH] 9p: fix enodata when reading growing file

Dominique Martinet <asmadeus@...ewreck.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/sec)
> 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@...ewreck.org>
> Co-authored-by: David Howells <dhowells@...hat.com>
> Cc: stable@...r.kernel.org

I think you want this also:

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

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