From: Trond Myklebust <trondmy@hammerspace.com>
To: "brauner@kernel.org" <brauner@kernel.org>,
"hch@infradead.org" <hch@infradead.org>
Cc: "jack@suse.cz" <jack@suse.cz>,
"chuck.lever@oracle.com" <chuck.lever@oracle.com>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"linux-api@vger.kernel.org" <linux-api@vger.kernel.org>,
"alex.aring@gmail.com" <alex.aring@gmail.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"cyphar@cyphar.com" <cyphar@cyphar.com>,
"viro@zeniv.linux.org.uk" <viro@zeniv.linux.org.uk>,
"jlayton@kernel.org" <jlayton@kernel.org>,
"amir73il@gmail.com" <amir73il@gmail.com>,
"linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH RFC v2] fhandle: expose u64 mount id to name_to_handle_at(2)
Date: Mon, 27 May 2024 15:47:33 +0000 [thread overview]
Message-ID: <49b6c50a50e517b6eb61d40af6fd1fd6e9c09cb2.camel@hammerspace.com> (raw)
In-Reply-To: <20240527-raufen-skorpion-fa81805b3273@brauner>
On Mon, 2024-05-27 at 15:17 +0200, Christian Brauner wrote:
>
> Returning the 64bit mount id makes this race-free because we now have
> statmount():
>
> u64 mnt_id = 0;
> name_to_handle_at(AT_FDCWD, "/path/to/file", &handle, &mnt_id, 0);
> statmount(mnt_id);
>
> Which gets you the device number which one can use to figure out the
> uuid without ever having to open a single file (We could even expose
> the
> UUID of the filesystem through statmount() if we wanted to.).
>
It is not race free. statmount() depends on the filesystem still being
mounted somewhere in your namespace, which is not guaranteed above.
--
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@hammerspace.com
next prev parent reply other threads:[~2024-05-27 15:47 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-23 20:57 [PATCH RFC v2] fhandle: expose u64 mount id to name_to_handle_at(2) Aleksa Sarai
2024-05-24 4:58 ` Amir Goldstein
2024-05-26 9:25 ` Christoph Hellwig
2024-05-26 19:01 ` Aleksa Sarai
2024-05-27 11:47 ` Christoph Hellwig
2024-05-27 12:29 ` Christian Brauner
2024-05-27 13:17 ` Christian Brauner
2024-05-27 15:47 ` Trond Myklebust [this message]
2024-05-28 7:05 ` Christian Brauner
2024-05-27 16:18 ` Christoph Hellwig
2024-05-27 13:34 ` Jan Kara
2024-05-27 16:24 ` Christoph Hellwig
2024-05-28 8:20 ` Christian Brauner
2024-05-28 8:28 ` Christoph Hellwig
2024-05-28 9:17 ` Christian Brauner
2024-05-28 10:55 ` Christoph Hellwig
2024-05-28 12:04 ` Christian Brauner
2024-05-28 13:22 ` Christoph Hellwig
2024-05-28 13:28 ` Miklos Szeredi
2024-05-29 6:34 ` Christoph Hellwig
2024-06-01 8:12 ` Aleksa Sarai
2024-06-03 10:30 ` Jan Kara
2024-06-04 5:22 ` Christoph Hellwig
2024-05-29 7:40 ` Christian Brauner
2024-05-31 8:14 ` Christoph Hellwig
2024-05-31 10:28 ` Christian Brauner
2024-05-26 22:32 ` Trond Myklebust
2024-05-27 11:49 ` hch
2024-05-27 15:38 ` Trond Myklebust
2024-05-27 16:29 ` hch
2024-05-28 7:12 ` Christian Brauner
2024-05-28 7:15 ` hch
2024-05-28 10:11 ` Jan Kara
2024-05-28 10:56 ` hch
2024-05-28 23:25 ` Dave Chinner
2024-05-29 6:24 ` hch
2024-05-29 7:23 ` Amir Goldstein
2024-05-27 12:22 ` Christian Brauner
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