From: Al Viro <viro@zeniv.linux.org.uk>
To: Mateusz Guzik <mjguzik@gmail.com>
Cc: brauner@kernel.org, jack@suse.cz, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org, clm@meta.com
Subject: Re: [PATCH v3] fs: make sure to fail try_to_unlazy() and try_to_unlazy() for LOOKUP_CACHED
Date: Sat, 20 Dec 2025 08:58:26 +0000 [thread overview]
Message-ID: <20251220085826.GB1712166@ZenIV> (raw)
In-Reply-To: <20251220054023.142134-1-mjguzik@gmail.com>
On Sat, Dec 20, 2025 at 06:40:22AM +0100, Mateusz Guzik wrote:
> Otherwise the slowpath can be taken by the caller, defeating the flag.
>
> This regressed after calls to legitimize_links() started being
> conditionally elided and stems from the routine always failing
> after seeing the flag, regardless if there were any links.
>
> In order to address both the bug and the weird semantics make it illegal
> to call legitimize_links() with LOOKUP_CACHED and handle the problem at
> the two callsites.
I still don't get what's weird about the semantics involved, but
the only question I've got is the location of this VFS_BUG_ON().
A way to ensure that we don't forget to check LOOKUP_CACHED early,
in both (seriously similar) callers?
Anyway, it does fix the regression.
next prev parent reply other threads:[~2025-12-20 8:57 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-20 5:40 [PATCH v3] fs: make sure to fail try_to_unlazy() and try_to_unlazy() for LOOKUP_CACHED Mateusz Guzik
2025-12-20 8:58 ` Al Viro [this message]
2025-12-20 9:07 ` Mateusz Guzik
2025-12-24 12:32 ` Christian Brauner
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