From: David Howells <dhowells@redhat.com>
Cc: dhowells@redhat.com,
Christian Schoenebeck <linux_oss@crudebyte.com>,
ericvh@kernel.org, lucho@ionkov.net, asmadeus@codewreck.org,
Pierre Barre <pierre@barre.sh>,
v9fs@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] 9p: fix i_size update race in getattr with writeback caching
Date: Tue, 17 Feb 2026 16:54:59 +0000 [thread overview]
Message-ID: <1499182.1771347299@warthog.procyon.org.uk> (raw)
In-Reply-To: <1406915.1771340720@warthog.procyon.org.uk>
David Howells <dhowells@redhat.com> wrote:
> > [ 60.847671] [append] R=134d: No submit
>
> Can you get me some tracing? If you can turn on:
Nevermind, I've managed to reproduce it - but only with the virtio transport
and not the tcp one. It also doesn't seem to show anything with afs.
9p_repro.sh-1399 : netfs_folio: i=d306b44 ix=00000-00000 mod-streamw
9p_repro.sh-1401 : netfs_folio: i=d306b44 ix=00000-00000 flush
9p_repro.sh-1401 : netfs_write: R=000001be WRITEBACK c=00000000 i=d306b44 by=0-ffffffffffffffff
9p_repro.sh-1401 : netfs_folio: i=d306b44 ix=00000-00000 store
kworker/u32:2-63 : netfs_rreq: R=000001be WB COLLECT f=903
kworker/u32:2-63 : netfs_rreq: R=000001be WB WR-DONE f=903
kworker/u32:2-63 : netfs_rreq: R=000001be WB WAKE-IP f=902
kworker/u32:2-63 : netfs_rreq: R=000001be WB FREE f=902
Looks like netfs failed to flush an incompatible streaming write. The folio
was moved to the 'store' state, but no subrequests were generated for some
reason.
*Why* it produced an incompatible streaming write is an interesting question.
The writes are all done with O_APPEND, so even if the processes write out of
order, there shouldn't be a problem...
David
next prev parent reply other threads:[~2026-02-17 16:55 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-27 18:01 [PATCH v2] 9p: fix i_size update race in getattr with writeback caching Pierre Barre
2026-01-05 11:35 ` Christian Schoenebeck
2026-01-07 0:27 ` Pierre Barre
2026-02-04 11:48 ` Christian Schoenebeck
2026-02-15 9:21 ` Dominique Martinet
2026-02-17 14:48 ` David Howells
2026-02-17 15:05 ` David Howells
2026-02-17 16:54 ` David Howells [this message]
2026-02-18 13:38 ` David Howells
2026-02-18 13:41 ` David Howells
2026-02-18 14:11 ` Dominique Martinet
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