Re: [PATCH 2/3] fd/locks: allow get the lock owner by F_OFD_GETLK
From: stsp
Date: Tue Jun 20 2023 - 06:57:55 EST
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@xxxxxxxxx>
CC: Jeff Layton <jlayton@xxxxxxxxxx>
CC: Chuck Lever <chuck.lever@xxxxxxxxxx>
CC: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
CC: Christian Brauner <brauner@xxxxxxxxxx>
CC: linux-fsdevel@xxxxxxxxxxxxxxx
CC: linux-kernel@xxxxxxxxxxxxxxx
---
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?