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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 09:10:55 +0100	[thread overview]
Message-ID: <2217384.1789114255@warthog.procyon.org.uk> (raw)
In-Reply-To: <fbb9e395-1e07-4212-8f70-23f3cd498074@method-b.uk>

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

>       cache=none       read   0/20  write   0/20  [cache=0x0]
>       cache=readahead  read   0/20  write   0/20  [cache=0x1]
>       cache=mmap       read  20/20  write  20/20  [cache=0x5]
>       cache=loose      read  20/20  write  20/20  [cache=0xf]
>       cache=fscache    read  20/20  write  20/20  [cache=0x8f]

I presume these should all be 0/20?  When I have a cachefiles cache active, I
see:

  cache=none       read   0/20  write   0/20  [cache=0x0]
  cache=readahead  read   0/20  write   0/20  [cache=0x1]
  cache=mmap       read  20/20  write  20/20  [cache=0x5]
  cache=loose      read  20/20  write  20/20  [cache=0xf]
  cache=fscache    read   0/20  write  20/20  [cache=0x8f]

so I suspect on the last one, the data is drawn from fscache, not from the
server.

David


  parent reply	other threads:[~2026-09-11  8:11 UTC|newest]

Thread overview: 12+ 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
2026-09-12  1:43   ` Dominique Martinet
2026-09-11  7:16 ` David Howells
2026-09-11  8:10 ` David Howells [this message]
2026-09-11  9:25 ` David Howells
2026-09-11 12:53   ` Michael Mulqueen
2026-09-11 13:13     ` David Howells
2026-09-12  8:06   ` Dominique Martinet
2026-09-13  7:55     ` David Howells
2026-09-13  8:56       ` Dominique Martinet

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