Re: [PATCH] tracefs/eventfs: Use root and instance inodes as default ownership

From: Matthew Wilcox <willy@infradead.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>,
	LKML <linux-kernel@vger.kernel.org>,
	Linux Trace Kernel <linux-trace-kernel@vger.kernel.org>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Christian Brauner <brauner@kernel.org>,
	linux-fsdevel@vger.kernel.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jonathan Corbet <corbet@lwn.net>,
	linux-doc@vger.kernel.org
Subject: Re: [PATCH] tracefs/eventfs: Use root and instance inodes as default ownership
Date: Thu, 4 Jan 2024 19:26:59 +0000	[thread overview]
Message-ID: <ZZcGg5/SFSOUC9PX@casper.infradead.org> (raw)
In-Reply-To: <20240104141517.0657b9d1@gandalf.local.home>

On Thu, Jan 04, 2024 at 02:15:17PM -0500, Steven Rostedt wrote:
> On Thu, 4 Jan 2024 18:25:02 +0000
> Al Viro <viro@zeniv.linux.org.uk> wrote:
> 
> > Unfortunately, the terms are clumsy as hell - POSIX ends up with
> > "file descriptor" (for numbers) vs. "file description" (for IO
> > channels), which is hard to distinguish when reading and just
> > as hard to distinguish when listening.  "Opened file" (as IO
> > channel) vs. "file on disc" (as collection of data that might
> > be accessed via said channels) distinction on top of that also
> > doesn't help, to put it mildly.  It's many decades too late to
> > do anything about, unfortunately.  Pity the UNIX 101 students... ;-/
> 
> Just so I understand this correctly.
> 
> "file descriptor" - is just what maps to a specific inode.

No -- file descriptor is a number in fdtable that maps to a struct file.

> "file description" - is how the file is accessed (position in the file and
> 			flags associated to how it was opened)

file description is posix's awful name for struct file.