From: David Howells <dhowells@redhat.com>
To: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: dhowells@redhat.com, viro@zeniv.linux.org.uk,
linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org,
linux-kernel@vger.kernel.org, mszeredi@redhat.com
Subject: Re: [PATCH 3/9] VFS: Introduce a mount context
Date: Thu, 04 May 2017 11:22:22 +0100 [thread overview]
Message-ID: <24143.1493893342@warthog.procyon.org.uk> (raw)
In-Reply-To: <87bmr939bg.fsf@rasmusvillemoes.dk>
Rasmus Villemoes <linux@rasmusvillemoes.dk> wrote:
> > + if (fs_type->fsopen && fs_type->mc_size < sizeof(*mc))
> > + BUG();
>
> So ->mc_size can be 0 (i.e. not explicitly initialized) if fs_type does
> not have ->fsopen. OK.
I need to be able to handle filesystems that don't support this yet. Once all
filesystems support this, I would be able to take away the max_t() thing.
> > + if (!src->ops->dup)
> > + return ERR_PTR(-ENOTSUPP);
> > +
> > + mc = kmemdup(src, src->fs_type->mc_size, GFP_KERNEL);
>
> So this assumes that vfs_dup_mount_context is only used if ->mc_size is
> explicitly initialized. A max_t here as well probably wouldn't hurt.
If you don't provide an ->fsopen() op, you can't set src->ops, you don't see a
mount context and you can't call this function. If you did supply an
->fsopen() op, the BUG() would've got you if you didn't set ->mc_size.
> > + unsigned short mc_size; /* Size of mount context to allocate */
>
> Any particular reason to use a short? The struct doesn't pack any better.
But it leaves a hole someone else can use. I try not to use fields larger
than I need to.
David
next prev parent reply other threads:[~2017-05-04 10:22 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-03 16:04 [RFC][PATCH 0/9] VFS: Introduce mount context David Howells
2017-05-03 16:04 ` [PATCH 1/9] Provide a function to create a NUL-terminated string from unterminated data David Howells
2017-05-03 16:55 ` Jeff Layton
2017-05-03 19:26 ` Rasmus Villemoes
2017-05-03 20:13 ` David Howells
2017-05-03 16:04 ` [PATCH 2/9] Clean up whitespace in fs/namespace.c David Howells
2017-05-03 16:04 ` [PATCH 3/9] VFS: Introduce a mount context David Howells
2017-05-03 18:13 ` Jeff Layton
2017-05-03 18:26 ` Joe Perches
2017-05-03 20:38 ` Matthew Wilcox
2017-05-03 21:36 ` Joe Perches
2017-05-04 6:28 ` Julia Lawall
2017-05-03 21:17 ` David Howells
2017-05-03 18:37 ` David Howells
2017-05-03 18:43 ` Joe Perches
2017-05-03 20:11 ` David Howells
2017-05-04 9:27 ` David Howells
2017-05-04 14:34 ` Joe Perches
2017-05-03 21:43 ` Rasmus Villemoes
2017-05-04 10:22 ` David Howells [this message]
2017-05-08 15:05 ` Miklos Szeredi
2017-05-08 22:57 ` David Howells
2017-05-09 8:03 ` Miklos Szeredi
2017-05-10 12:41 ` Karel Zak
2017-05-09 9:32 ` David Howells
2017-05-09 11:04 ` Miklos Szeredi
2017-05-09 9:41 ` David Howells
2017-05-09 12:02 ` Miklos Szeredi
2017-05-09 18:51 ` Jeff Layton
2017-05-10 7:24 ` Miklos Szeredi
2017-05-10 8:05 ` David Howells
2017-05-10 13:20 ` Jeff Layton
2017-05-10 13:30 ` Miklos Szeredi
2017-05-10 13:33 ` Miklos Szeredi
2017-05-10 13:48 ` Jeff Layton
2017-05-12 8:15 ` Miklos Szeredi
2017-05-10 13:31 ` David Howells
2017-05-10 13:37 ` Jeff Layton
2017-05-09 9:56 ` David Howells
2017-05-09 12:38 ` Miklos Szeredi
2017-05-03 16:05 ` [PATCH 4/9] Implement fsopen() to prepare for a mount David Howells
2017-05-03 18:37 ` Jeff Layton
2017-05-03 18:41 ` David Howells
2017-05-03 20:44 ` Rasmus Villemoes
2017-05-04 10:40 ` Karel Zak
2017-05-04 12:55 ` David Howells
2017-05-04 12:58 ` David Howells
2017-05-04 13:06 ` David Howells
2017-05-04 13:34 ` Karel Zak
2017-05-09 18:40 ` Jeff Layton
2017-05-08 15:10 ` Miklos Szeredi
2017-05-08 23:09 ` David Howells
2017-05-03 16:05 ` [PATCH 5/9] Implement fsmount() to effect a pre-configured mount David Howells
2017-05-03 16:05 ` [PATCH 6/9] Sample program for driving fsopen/fsmount David Howells
2017-05-03 16:05 ` [PATCH 7/9] procfs: Move proc_fill_super() to fs/proc/root.c David Howells
2017-05-03 16:05 ` [PATCH 8/9] proc: Support the mount context in procfs David Howells
2017-05-03 16:05 ` [PATCH 9/9] NFS: Support the mount context and fsopen() David Howells
2017-05-03 16:44 ` [RFC][PATCH 0/9] VFS: Introduce mount context Jeff Layton
2017-05-03 16:50 ` David Howells
2017-05-03 17:27 ` Jeff Layton
2017-05-05 14:35 ` Miklos Szeredi
2017-05-05 15:47 ` David Howells
2017-05-08 8:25 ` Miklos Szeredi
2017-05-08 8:35 ` David Howells
2017-05-08 8:43 ` Miklos Szeredi
2017-05-08 17:03 ` Djalal Harouni
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