From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B4065152E1D; Tue, 23 Jul 2024 13:16:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721740573; cv=none; b=ZEWOsw1meQRUGioDvaqJ6nAj3mP61Qe8/xzjNmCkW/eX5W/u6RQTY9pH4E8rilredKjbKUWcAL+asQ6CEiVBXDhIQ90Pyofcx1WX1nSsYHBgmgnIDkPwVOhCH+YVU4CrdFPWYkpzsydekyXDmvIc7EODChXPdsayEQrrrmPyf/Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721740573; c=relaxed/simple; bh=KWifQZqQ8T0lPyWaVa/Z6CVrrNBq2dz1vtCZNDGJaF4=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=oPFU5Tei7ayW1Ebfu+vqKZCItg+KtpPgeXNrczEgR4IMOkiU6BwohndKG0MExvQCaI1QuZT0XeCxqRTJOlvMC2IFV2KRmNlLBGoYx1UTiIYerDoyBnFsGR7SUfUV8rKvdAGjNp4Oe7lpj3IZDm2Z0bAIlBSvIC64VK2jkMmB9sY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=AZhAOtM4; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="AZhAOtM4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5DBEEC4AF0A; Tue, 23 Jul 2024 13:16:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1721740573; bh=KWifQZqQ8T0lPyWaVa/Z6CVrrNBq2dz1vtCZNDGJaF4=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=AZhAOtM4TNL2zitLuFmXduh3EIZQqqDE2vZvgYKx7bzSV/1F43u+MiabUx13sLV/w ituKOro2E8t0h4EgjbeFIwOSWDVVfn5C2p1vhZmy0Xpmgddie2AAa0fKFmdmxnF26a 9wxHCU4HXuaP/dxrBz/apKDRKLXoxYwFXQmBvKAtSqayXL4yoyz+Ki77k21PzXCRoL NWNCy4gTvpFj/ucdrPREkRGjSysnBEaJp2VwInoORvzYt2ZaGvafh16N/5qTefRWRc UV3aqmkYpK3Gl8aN5MacpadAHndXHIyWsl21o5TB/mmUB1YGDueCvietEYdXzWUaxY c29V7FN7RVDjw== Message-ID: <7ce8cadfc432368924134ae96f8d9710282a15d6.camel@kernel.org> Subject: Re: [PATCH] filelock: add file path in lock_get_status() to show more debug info From: Jeff Layton To: Yuwei Guan , chuck.lever@oracle.com, alex.aring@gmail.com, viro@zeniv.linux.org.uk, brauner@kernel.org, jack@suse.cz Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, ssawgyw@gmail.com, Dashi.Luban@zeekrlife.com Date: Tue, 23 Jul 2024 09:16:10 -0400 In-Reply-To: <20240723123816.3676322-1-Yuwei.Guan@zeekrlife.com> References: <20240723123816.3676322-1-Yuwei.Guan@zeekrlife.com> Autocrypt: addr=jlayton@kernel.org; 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charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.50.4 (3.50.4-1.fc39) Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Tue, 2024-07-23 at 20:38 +0800, Yuwei Guan wrote: > The current lock_get_status() function shows ino, but it=E2=80=99s not > intuitive enough for debugging. This patch will add the file=E2=80=99s > path information, making it easier to debug which specific file > is holding the lock. >=20 > Signed-off-by: Yuwei Guan > --- > =C2=A0fs/locks.c | 25 ++++++++++++++++++++++++- > =C2=A01 file changed, 24 insertions(+), 1 deletion(-) >=20 > diff --git a/fs/locks.c b/fs/locks.c > index bdd94c32256f..feb0a4427a5b 100644 > --- a/fs/locks.c > +++ b/fs/locks.c > @@ -2764,6 +2764,8 @@ static void lock_get_status(struct seq_file *f, > struct file_lock_core *flc, > =C2=A0 struct pid_namespace *proc_pidns =3D proc_pid_ns(file_inode(f- > >file)->i_sb); > =C2=A0 int type =3D flc->flc_type; > =C2=A0 struct file_lock *fl =3D file_lock(flc); > + struct dentry *dentry =3D NULL; > + char *path, *pathbuf; > =C2=A0 > =C2=A0 pid =3D locks_translate_pid(flc, proc_pidns); > =C2=A0 > @@ -2819,8 +2821,29 @@ static void lock_get_status(struct seq_file > *f, struct file_lock_core *flc, > =C2=A0 seq_printf(f, "%d %02x:%02x:%lu ", pid, > =C2=A0 MAJOR(inode->i_sb->s_dev), > =C2=A0 MINOR(inode->i_sb->s_dev), inode- > >i_ino); > + > + pathbuf =3D __getname(); This won't work. locks_show is called under the blocked_lock_lock spinlock, and __getname does a GFP_KERNEL allocation. The second problem is that the procfiles that this alters (/proc/locks and /proc//fdinfo/*) are considered part of the kernel's ABI, so we can't just go change the format of them. If you're interested in getting pathnames, I suggest using the lslocks program which resolves these pathnames in userland. > + if (!pathbuf) > + seq_printf(f, "%s ", "UNKNOWN"); > + else { > + ihold(inode); > + dentry =3D d_obtain_alias(inode); > + if (!IS_ERR(dentry)) { > + path =3D dentry_path_raw(dentry, > pathbuf, PATH_MAX); > + if (IS_ERR(path)) { > + strscpy(pathbuf, "UNKNOWN", > PATH_MAX); > + path =3D pathbuf; > + } > + dput(dentry); > + } else { > + strscpy(pathbuf, "UNKNOWN", > PATH_MAX); > + path =3D pathbuf; > + } > + seq_printf(f, "%s ", path); > + __putname(pathbuf); > + } > =C2=A0 } else { > - seq_printf(f, "%d :0 ", pid); > + seq_printf(f, "%d :0: UNKNOWN ", pid); > =C2=A0 } > =C2=A0 if (flc->flc_flags & FL_POSIX) { > =C2=A0 if (fl->fl_end =3D=3D OFFSET_MAX) --=20 Jeff Layton