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From: David Howells <dhowells@redhat.com>
To: Michael Mulqueen <mike@method-b.uk>
Cc: dhowells@redhat.com, ericvh@kernel.org, lucho@ionkov.net,
	asmadeus@codewreck.org, pc@manguebit.org,
	linux_oss@crudebyte.com, v9fs@lists.linux.dev,
	netfs@lists.linux.dev, linux-fsdevel@vger.kernel.org,
	regressions@lists.linux.dev
Subject: Re: PROBLEM: [REGRESSION 7.1-rc4 -> 7.1-rc5] 9p: silent NUL corruption of file data on cache modes with CACHE_WRITEBACK
Date: Fri, 11 Sep 2026 08:16:46 +0100	[thread overview]
Message-ID: <2208516.1789111006@warthog.procyon.org.uk> (raw)
In-Reply-To: <fbb9e395-1e07-4212-8f70-23f3cd498074@method-b.uk>

Michael Mulqueen <mike@method-b.uk> wrote:

> A 9p mount returns NULs in place of file contents the server holds, and can
> write those NULs back over the server's copy. Nothing reports an error - the
> read succeeds and the file is the correct length. Affects CACHE_WRITEBACK 
> modes - mmap, loose and fscache - but not none or readahead.

Are you actually using this with a cache?  Or just enabling the "use a cache"
options?

David


  parent reply	other threads:[~2026-09-11  7:17 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-10 10:56 PROBLEM: [REGRESSION 7.1-rc4 -> 7.1-rc5] 9p: silent NUL corruption of file data on cache modes with CACHE_WRITEBACK Michael Mulqueen
2026-09-10 12:23 ` Dominique Martinet
2026-09-10 14:06 ` Christian Schoenebeck
2026-09-11  7:16 ` David Howells [this message]
2026-09-11  8:10 ` David Howells
2026-09-11  9:25 ` David Howells
2026-09-11 12:53   ` Michael Mulqueen

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