From: Al Viro <viro@ZenIV.linux.org.uk>
To: David Howells <dhowells@redhat.com>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-security-module@vger.kernel.org, miklos@szeredi.hu
Subject: Re: [RFC] readlink()-related oddities
Date: Fri, 20 Nov 2015 22:33:43 +0000 [thread overview]
Message-ID: <20151120223343.GO22011@ZenIV.linux.org.uk> (raw)
In-Reply-To: <22313.1448013545@warthog.procyon.org.uk>
On Fri, Nov 20, 2015 at 09:59:05AM +0000, David Howells wrote:
> There's an AFS userspace command that could be used to query a mountpoint that
> was going to use it. However, I suspect readlink() will now always trigger
> the automount.
It won't, actually. All we are passing to user_path_at_empty() is
LOOKUP_EMPTY, so for the final component we'll have
if (!(nd->flags & (LOOKUP_PARENT | LOOKUP_DIRECTORY |
LOOKUP_OPEN | LOOKUP_CREATE | LOOKUP_AUTOMOUNT)) &&
path->dentry->d_inode)
return -EISDIR;
in follow_automount() trigger and follow_managed() will turn that -EISDIR
into 0. IOW, readlink(2) does work on those, same as stat() (since Sep 2011).
Sigh... OK, let's leave it for now; ->open() for those guys is completely
bogus, AFAICS, but that's local bogo^Wbusiness.
prev parent reply other threads:[~2015-11-20 22:33 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-19 23:26 [RFC] readlink()-related oddities Al Viro
2015-11-20 2:13 ` Linus Torvalds
2015-11-20 2:57 ` Al Viro
2015-11-20 3:09 ` Linus Torvalds
2015-11-20 3:16 ` Linus Torvalds
2015-11-20 3:24 ` Al Viro
2015-11-20 10:00 ` David Howells
2015-11-20 9:59 ` David Howells
2015-11-20 16:08 ` Al Viro
2015-11-20 16:26 ` David Howells
2015-11-20 22:33 ` Al Viro [this message]
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