Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751595AbdFGLkO (ORCPT ); Wed, 7 Jun 2017 07:40:14 -0400 Received: from mail-qk0-f196.google.com ([209.85.220.196]:36099 "EHLO mail-qk0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751483AbdFGLkM (ORCPT ); Wed, 7 Jun 2017 07:40:12 -0400 Message-ID: <1496835607.3703.1.camel@poochiereds.net> Subject: Re: [PATCH 3/3] fs/locks: Use fs-specific l_pid for remote locks From: Jeff Layton To: Benjamin Coddington , bfields@fieldses.org, Alexander Viro Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 07 Jun 2017 07:40:07 -0400 In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.22.6 (3.22.6-2.fc25) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3896 Lines: 101 On Tue, 2017-06-06 at 16:45 -0400, Benjamin Coddington wrote: > Now that we're translating fl_pid for F_GETLK and /proc/locks, we need to > handle the case where a remote filesystem directly sets fl_pid. In that > case, the fl_pid should not be translated into a local pid namespace. If > the filesystem implements the lock operation, set a flag to return the > lock's fl_pid value directly, rather translate it. > Actually, you're not translating anything for F_GETLK until we get to this patch. Patch #2 in this series removes the fl_nspid field, but the pid translation isn't fixed until here. That does mean a nominal regression here in how fl_pid is reported between the two. Would it be best to squash #2 and #3 together? Or maybe just go ahead and universally translate the fl_pid field until you add the flag in this patch? Also to make sure I understand: task->tgid will always represent the task's pid in the init_pid_ns, right? Other than the minor bisectability concern, I think this looks good. Nice work! > Signed-off-by: Benjamin Coddington > --- > fs/locks.c | 22 ++++++++++++++++++---- > include/linux/fs.h | 1 + > 2 files changed, 19 insertions(+), 4 deletions(-) > > diff --git a/fs/locks.c b/fs/locks.c > index 8d48e4c42ed3..206a46d28bbd 100644 > --- a/fs/locks.c > +++ b/fs/locks.c > @@ -2034,8 +2034,10 @@ SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd) > */ > int vfs_test_lock(struct file *filp, struct file_lock *fl) > { > - if (filp->f_op->lock && is_remote_lock(filp)) > + if (filp->f_op->lock && is_remote_lock(filp)) { > + fl->fl_flags |= FL_PID_PRIV; > return filp->f_op->lock(filp, F_GETLK, fl); > + } > posix_test_lock(filp, fl); > return 0; > } > @@ -2060,9 +2062,18 @@ static pid_t locks_translate_pid(int init_nr, struct pid_namespace *ns) > return vnr; > } > > +static pid_t flock_translate_pid(struct file_lock *fl) > +{ > + if (IS_OFDLCK(fl)) > + return -1; > + if (fl->fl_flags & FL_PID_PRIV) > + return fl->fl_pid; > + return locks_translate_pid(fl->fl_pid, task_active_pid_ns(current)); > +} > + > static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl) > { > - flock->l_pid = IS_OFDLCK(fl) ? -1 : fl->fl_pid; > + flock->l_pid = flock_translate_pid(fl); > #if BITS_PER_LONG == 32 > /* > * Make sure we can represent the posix lock via > @@ -2084,7 +2095,7 @@ static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl) > #if BITS_PER_LONG == 32 > static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl) > { > - flock->l_pid = IS_OFDLCK(fl) ? -1 : fl->fl_pid; > + flock->l_pid = flock_translate_pid(fl); > flock->l_start = fl->fl_start; > flock->l_len = fl->fl_end == OFFSET_MAX ? 0 : > fl->fl_end - fl->fl_start + 1; > @@ -2598,7 +2609,10 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl, > unsigned int fl_pid; > struct pid_namespace *proc_pidns = file_inode(f->file)->i_sb->s_fs_info; > > - fl_pid = locks_translate_pid(fl->fl_pid, proc_pidns); > + if (fl->fl_flags & FL_PID_PRIV) > + fl_pid = fl->fl_pid; > + else > + fl_pid = locks_translate_pid(fl->fl_pid, proc_pidns); > /* > * If there isn't a fl_pid don't display who is waiting on > * the lock if we are called from locks_show, or if we are > diff --git a/include/linux/fs.h b/include/linux/fs.h > index b013fac515f7..179496a9719d 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -908,6 +908,7 @@ static inline struct file *get_file(struct file *f) > #define FL_UNLOCK_PENDING 512 /* Lease is being broken */ > #define FL_OFDLCK 1024 /* lock is "owned" by struct file */ > #define FL_LAYOUT 2048 /* outstanding pNFS layout */ > +#define FL_PID_PRIV 4096 /* F_GETLK should report fl_pid */ > > #define FL_CLOSE_POSIX (FL_POSIX | FL_CLOSE) > -- Jeff Layton