From mboxrd@z Thu Jan 1 00:00:00 1970 From: Davidlohr Bueso Subject: Re: [PATCH] locks: export device name Date: Wed, 15 Feb 2012 11:52:42 +0100 Message-ID: <1329303162.3356.6.camel@offbook> References: <1328907967.3138.1.camel@offbook> <20120213163425.dd9adfde.akpm@linux-foundation.org> <20120214190906.GA5115@fieldses.org> Reply-To: dave@gnu.org Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Andrew Morton , Matthew Wilcox , linux-fsdevel , lkml To: "J. Bruce Fields" Return-path: In-Reply-To: <20120214190906.GA5115@fieldses.org> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Tue, 2012-02-14 at 14:09 -0500, J. Bruce Fields wrote: > On Mon, Feb 13, 2012 at 04:34:25PM -0800, Andrew Morton wrote: > > On Fri, 10 Feb 2012 22:06:07 +0100 > > Davidlohr Bueso wrote: > > > > > From: Davidlohr Bueso > > > > > > The lslk(8) program has not been maintained for over a decade and has recently been rewritten as lslocks(8). > > > It will be available for the next 2.22 release, in a couple of months. This is a good opportunity to delete > > > that nasty WE_CAN_BREAK_LSLK_NOW and start exporting the device name instead of the maj:min numbers. > > > > > > For backward compatibility the new version can be in charge of checking older kernel versions and parsing the old > > > output if necessary. > > > > > > ... > > > > > > --- a/fs/locks.c > > > +++ b/fs/locks.c > > > @@ -2199,15 +2199,8 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl, > > > : (fl->fl_type & F_WRLCK) ? "WRITE" : "READ "); > > > } > > > if (inode) { > > > -#ifdef WE_CAN_BREAK_LSLK_NOW > > > seq_printf(f, "%d %s:%ld ", fl_pid, > > > inode->i_sb->s_id, inode->i_ino); > > > -#else > > > - /* userspace relies on this representation of dev_t ;-( */ > > > - seq_printf(f, "%d %02x:%02x:%ld ", fl_pid, > > > - MAJOR(inode->i_sb->s_dev), > > > - MINOR(inode->i_sb->s_dev), inode->i_ino); > > > -#endif > > > } else { > > > seq_printf(f, "%d :0 ", fl_pid); > > > } > > > > I don't get it. This is an immediate and non-back-compatible change to > > the format of /proc/locks. The only way this can avoid breaking things > > is if there are no programs or scripts in use by anyone which use > > this field. What am I missing here? > > I'm a little surprised anything parses that file. To my knowledge only lslk - but the whole point here is that its going to be replaced by lslocks. > > But, yes, looks like I can "yum install" lslk on Fedora 16, as an > example. Can't get it to do anything useful, though. Does it actually > work on any recent distro? It works on Ubuntu's latest release. > > Perhaps safest would be to replace /proc/locks by another interface and > deprecate this one. If exporting the name in the current /proc/locks file is out of the question, then IMHO I don't think it would be worth adding a new interface just for such a small change. Thanks, Davidlohr