From: David Howells <dhowells@redhat.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: dhowells@redhat.com, viro@zeniv.linux.org.uk,
linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org,
torvalds@linux-foundation.org, linux-afs@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] afs: Add metadata xattrs
Date: Thu, 06 Jul 2017 17:14:11 +0100 [thread overview]
Message-ID: <31934.1499357651@warthog.procyon.org.uk> (raw)
In-Reply-To: <20170706152304.GA10584@infradead.org>
Christoph Hellwig <hch@infradead.org> wrote:
> NAK. Don't overload xattrs with magic behavior just to avoid the need
> to do proper syscalls or ioctls.
How? This has to work on non-files, files you can't open and mountpoints.
You can't do an ioctl() on a file opened O_PATH:
if (unlikely(f->f_flags & O_PATH)) {
f->f_mode = FMODE_PATH;
f->f_op = &empty_fops;
return 0;
}
and you can't specify AT_NO_AUTOMOUNT or AT_NO_FOLLOW to openat(), so ioctl()
is of no use here.
Do you advocate introducing a pioctl() call? Linus was dead-set against that
as I recall.
I could invent a bunch of AFS-specific syscalls, but I'd rather not do that or
I suppose bring my fsinfo() patches up to scratch - but you didn't like those
either.
Note that using xattrs for fs info is not without precedent in Linux - cifs,
for example.
David
next prev parent reply other threads:[~2017-07-06 16:14 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <149935261019.29744.8564287571048506851.stgit@warthog.procyon.org.uk>
[not found] ` <149935262759.29744.6299062653432480230.stgit@warthog.procyon.org.uk>
2017-07-06 15:23 ` [PATCH 2/2] afs: Add metadata xattrs Christoph Hellwig
2017-07-06 16:14 ` David Howells [this message]
2017-07-06 18:27 ` Andreas Dilger
2017-07-08 19:44 ` Linus Torvalds
2017-07-09 1:01 ` Theodore Ts'o
[not found] ` <20170709010155.3nql5ixdeozemgfd-AKGzg7BKzIDYtjvyW6yDsg@public.gmane.org>
2017-07-09 2:37 ` Jeffrey Altman
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