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Re: [PATCH] locks: rename file-private locks to file-description locks
- From: "Michael Kerrisk (man-pages)" <mtk dot manpages at gmail dot com>
- To: Rich Felker <dalias at libc dot org>
- Cc: mtk dot manpages at gmail dot com, Jeff Layton <jlayton at redhat dot com>, linux-fsdevel at vger dot kernel dot org, linux-kernel at vger dot kernel dot org, samba-technical at lists dot samba dot org, Ganesha NFS List <nfs-ganesha-devel at lists dot sourceforge dot net>, Carlos O'Donell <carlos at redhat dot com>, libc-alpha <libc-alpha at sourceware dot org>, "Stefan (metze) Metzmacher" <metze at samba dot org>, Christoph Hellwig <hch at infradead dot org>
- Date: Mon, 21 Apr 2014 21:39:12 +0200
- Subject: Re: [PATCH] locks: rename file-private locks to file-description locks
- Authentication-results: sourceware.org; auth=none
- References: <1398087935-14001-1-git-send-email-jlayton at redhat dot com> <20140421140246 dot GB26358 at brightrain dot aerifal dot cx> <535529FA dot 8070709 at gmail dot com> <20140421161004 dot GC26358 at brightrain dot aerifal dot cx> <5355644C dot 7000801 at gmail dot com> <20140421184640 dot GD26358 at brightrain dot aerifal dot cx>
On 04/21/2014 08:46 PM, Rich Felker wrote:
> On Mon, Apr 21, 2014 at 08:32:44PM +0200, Michael Kerrisk (man-pages) wrote:
>> On 04/21/2014 06:10 PM, Rich Felker wrote:
>>> I'm well aware of that. The problem is that the proposed API is using
>>> the two-letter abbreviation FD, which ALWAYS means file descriptor and
>>> NEVER means file description (in existing usage) to mean file
>>> description. That's what's wrong.
>> So, can you *please* answer this question: what do you call (i.e.,
>> what everyday technical language term do use for) the thing
>> that sits between a file descriptor and an i-node?
>> (Please don't say 'struct file' -- that is not is an implementation
>> detail, and does not qualify as the kind of term that I could use
>> when documenting this feature in man pages.)
> "Open file description".
Oh! I didn't realize we agreed :-).
>> POSIX uses (or invented, I am not sure which) the term file description
>> for a good reason: it is unambiguous, and therefore precise. I do agree
>> that there's a risk of confusion between 'open file descriptor" and
>> 'and file description'--it's the same kind of risk as between English
>> terms such as 'arbitrator' and 'arbitration' (and any number of other
>> examples), and as language speakers we deal with this every day.
> There's not a problem when the full word is used. On the other hand,
> if you use "arb" as an abbreviation for "arbitration" in a context
> where it was already universally understood as meaning "arbitrator",
> that would be a big problem.
> Likewise the problem here isn't that "open file description" is a bad
> term. It's that using "FD" to mean "[open] file description" is
> utterly confusing, even moreso than just making up a new completely
> random word.
Ohh -- I had thought you a problem not just with "FD" but also
"(open) file description".
>>>> 2) The new API constants (F_SETLKP, F_SETLKPW, F_GETLKP) have names
>>>> that are visually very close to the traditional POSIX lock names
>>>> (F_SETLK, F_SETLKW, F_GETLK). That's an accident waiting to happen
>>>> when someone mistypes in code and/or misses such a misttyping
>>>> when reading code. That really must be fixed.
>>> I agree, but I don't think making it worse is a solution.
>> I don't agree that it's making it worse. The real problem here is
>> that people use no good unambiguous term for the thing between a file
>> descriptor and an inode. POSIX provides us with a solution that may
>> not seem perfect, but it is unambiguous, and I think it might feel
>> more comfortable if we used it often enough.
> I would like to see it used more too, and in particular, I think it
> belongs in the documentation for these new locking interfaces. But
> that still doesn't answer the question of what to call them (the
> macros) unless you want:
Or just 'F_OFD_*'?
> Perhaps "OP" (for open-private, i.e. private to the particular open)
> would be a sensible choice; OTOH people are likely to misread it as
> OPeration. The general principle I have in mind though is that it
> might be nice to highlight the word "open" in "open file description"
> since it (1) contrasts with file descriptor, despite file descriptors
> also dealing with open files, and (2) contrasts well with legacy fcntl
> locks, which are (this is the whole bug) associated with the
> underlying file and not the open file description.
Makes sense to me. (We are in more agreement that I realized.)
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