From: stsp <stsp2@yandex.ru>
To: Jeff Layton <jlayton@kernel.org>, linux-kernel@vger.kernel.org
Cc: Chuck Lever <chuck.lever@oracle.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Christian Brauner <brauner@kernel.org>,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 2/3] fd/locks: allow get the lock owner by F_OFD_GETLK
Date: Tue, 20 Jun 2023 15:57:23 +0500 [thread overview]
Message-ID: <a1e7f5c1-76ef-19e5-91db-a62f7615b28a@yandex.ru> (raw)
In-Reply-To: <5728ebda22a723b0eb209ae078e8f132d7b4ac7b.camel@kernel.org>
Hello,
20.06.2023 15:51, Jeff Layton пишет:
> On Tue, 2023-06-20 at 14:55 +0500, Stas Sergeev wrote:
>> Currently F_OFD_GETLK sets the pid of the lock owner to -1.
>> Remove such behavior to allow getting the proper owner's pid.
>> This may be helpful when you want to send some message (like SIGKILL)
>> to the offending locker.
>>
>> Signed-off-by: Stas Sergeev <stsp2@yandex.ru>
>>
>> CC: Jeff Layton <jlayton@kernel.org>
>> CC: Chuck Lever <chuck.lever@oracle.com>
>> CC: Alexander Viro <viro@zeniv.linux.org.uk>
>> CC: Christian Brauner <brauner@kernel.org>
>> CC: linux-fsdevel@vger.kernel.org
>> CC: linux-kernel@vger.kernel.org
>>
>> ---
>> fs/locks.c | 2 --
>> 1 file changed, 2 deletions(-)
>>
>> diff --git a/fs/locks.c b/fs/locks.c
>> index 210766007e63..ee265e166542 100644
>> --- a/fs/locks.c
>> +++ b/fs/locks.c
>> @@ -2158,8 +2158,6 @@ static pid_t locks_translate_pid(struct file_lock *fl, struct pid_namespace *ns)
>> pid_t vnr;
>> struct pid *pid;
>>
>> - if (IS_OFDLCK(fl))
>> - return -1;
>> if (IS_REMOTELCK(fl))
>> return fl->fl_pid;
>> /*
> NACK on this one.
>
> OFD locks are not owned by processes. They are owned by the file
> description (hence the name). Because of this, returning a pid here is
> wrong.
But fd is owned by a process.
PID has a meaning, you can send SIGKILL
to the returned PID, and the lock is clear.
Was there any reason to hide the PID at
a first place?
> This precedent comes from BSD, where flock() and POSIX locks can
> conflict. BSD returns -1 for the pid if you call F_GETLK on a file
> locked with flock(). Since OFD locks have similar ownership semantics to
> flock() locks, we use the same convention here.
OK if you insist I can drop this one and
search the PID by some other means.
Just a bit unsure what makes it so important
to overwrite the potentially useful info
with -1.
So in case you insist on that, then should
I send a v2 or can you just drop the patch
yourself?
next prev parent reply other threads:[~2023-06-20 10:57 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 [this message]
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
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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