From: Al Viro <viro@zeniv.linux.org.uk>
To: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Guoyu Ou <benogy@gmail.com>, linux-bcachefs@vger.kernel.org
Subject: Re: [PATCH] bcachefs: unlock parent dir if entry is not found in subvolume deletion
Date: Mon, 29 Jan 2024 03:15:17 +0000 [thread overview]
Message-ID: <20240129031517.GA26059@ZenIV> (raw)
In-Reply-To: <20240129022338.GH2087318@ZenIV>
On Mon, Jan 29, 2024 at 02:23:38AM +0000, Al Viro wrote:
> On Sun, Jan 28, 2024 at 09:21:48PM -0500, Kent Overstreet wrote:
>
> > How do we feel about the following?
>
> No, with side of Fuck, NO.
To elaborate a bit: that essentially introduces a new type (mount/dentry
pair, possibly locked) *and* converts existing instances of struct path
(file->f_path, mount->mnt_mountpoint, etc.) to that. Suddenly we get
an extra constraint that needs to be verified - "no long-term struct
path instance with ->locked being true". What's more, currently
one can do
v = *p;
path_get(&v);
...
path_put(&v);
with eventual
path_put(p);
possibly from another thread. Every place like that needs a proof that
we can't possibly get there with p->locked being true.
There's a lot of other reasons why that's a really bad idea. Seriously,
let's not go there.
next prev parent reply other threads:[~2024-01-29 3:15 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-28 8:46 [PATCH] bcachefs: unlock parent dir if entry is not found in subvolume deletion Guoyu Ou
2024-01-29 2:21 ` Kent Overstreet
2024-01-29 2:23 ` Al Viro
2024-01-29 3:15 ` Al Viro [this message]
2024-01-29 2:30 ` Al Viro
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20240129031517.GA26059@ZenIV \
--to=viro@zeniv.linux.org.uk \
--cc=benogy@gmail.com \
--cc=kent.overstreet@linux.dev \
--cc=linux-bcachefs@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox