From: David Laight <David.Laight@ACULAB.COM>
To: 'Matthew Wilcox' <willy@infradead.org>, stsp <stsp2@yandex.ru>
Cc: Jeff Layton <jlayton@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Chuck Lever <chuck.lever@oracle.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Christian Brauner <brauner@kernel.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>
Subject: RE: [PATCH 2/3] fd/locks: allow get the lock owner by F_OFD_GETLK
Date: Fri, 23 Jun 2023 13:10:26 +0000 [thread overview]
Message-ID: <f712a5551ebd4626acd17ac80fe51879@AcuMS.aculab.com> (raw)
In-Reply-To: <ZJGtmrej8LraEsjj@casper.infradead.org>
From: Matthew Wilcox
> Sent: 20 June 2023 14:46
>
> On Tue, Jun 20, 2023 at 06:39:07PM +0500, stsp wrote:
> > Though it will, for sure, represent the
> > task that _owns_ the lock.
>
> No, it *DOESN'T*. I can open a file, SCM_RIGHTS pass it to another task
> and then exit. Now the only owner of that lock is the recipient ...
> who may not even have received the fd yet.
Do these locks persist across fork+exec?
What happens is a completely unrelated process opens /proc/<pid>/fd
while a lock is held and then the (nominally) lock-holding
process closes the fd (or exits).
While it might be a useful diagnostic to know the pid of the
process that acquired the lock it clearly has no relationship
with any process that currently has an fd[] table entry that
references the file.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2023-06-23 13:10 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-20 9:55 [PATCH 0/3] RFC: F_OFD_GETLK should provide more info Stas Sergeev
2023-06-20 9:55 ` [PATCH 1/3] fs/locks: F_UNLCK extension for F_OFD_GETLK Stas Sergeev
2023-06-20 10:46 ` Jeff Layton
2023-06-20 11:00 ` stsp
2023-06-20 11:15 ` Jeff Layton
2023-06-21 15:24 ` stsp
2023-06-20 9:55 ` [PATCH 2/3] fd/locks: allow get the lock owner by F_OFD_GETLK Stas Sergeev
2023-06-20 10:51 ` Jeff Layton
2023-06-20 10:57 ` stsp
2023-06-20 11:12 ` Jeff Layton
2023-06-20 11:45 ` stsp
2023-06-20 12:02 ` Jeff Layton
2023-06-20 12:34 ` stsp
2023-06-20 13:19 ` Jeff Layton
2023-06-20 13:39 ` stsp
2023-06-20 13:46 ` Matthew Wilcox
2023-06-20 13:47 ` stsp
2023-06-20 14:36 ` Matthew Wilcox
2023-06-20 15:45 ` stsp
2023-06-20 17:05 ` Matthew Wilcox
2023-06-21 2:54 ` stsp
2023-06-23 13:10 ` David Laight [this message]
2023-06-20 13:58 ` Jeff Layton
2023-06-21 6:57 ` stsp
2023-06-21 10:35 ` Jeff Layton
2023-06-21 10:42 ` stsp
2023-06-21 11:05 ` Jeff Layton
2023-06-21 11:22 ` stsp
2023-06-21 11:26 ` stsp
2023-06-23 15:25 ` Christian Brauner
2023-06-23 17:18 ` stsp
2023-06-27 16:00 ` Jeff Layton
2023-06-27 16:20 ` stsp
2023-06-20 9:55 ` [PATCH 3/3] selftests: add OFD lock tests Stas Sergeev
2023-06-20 11:06 ` Jeff Layton
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