From mboxrd@z Thu Jan 1 00:00:00 1970 From: Al Viro Subject: Re: [RFC PATCH] autofs: find_autofs_mount overmounted parent support Date: Mon, 8 Mar 2021 00:28:14 +0000 Message-ID: References: <20210303152931.771996-1-alexander.mikhalitsyn@virtuozzo.com> <832c1a384dc0b71b2902accf3091ea84381acc10.camel@themaw.net> <20210304131133.0ad93dee12a17f41f4052bcb@virtuozzo.com> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: Sender: Al Viro List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Alexander Mikhalitsyn Cc: Ian Kent , Matthew Wilcox , Pavel Tikhomirov , Kirill Tkhai , autofs@vger.kernel.org, linux-kernel@vger.kernel.org, Miklos Szeredi , Christian Brauner , Ross Zwisler , Aleksa Sarai , Eric Biggers , Mattias Nissler , linux-fsdevel@vger.kernel.org, alexander@mihalicyn.com On Mon, Mar 08, 2021 at 12:12:22AM +0000, Al Viro wrote: > Wait, so you have /proc overmounted, without anything autofs-related on > /proc/sys/fs/binfmt_misc and still want to have the pathname resolved, just > because it would've resolved with that overmount of /proc removed? > > I hope I'm misreading you; in case I'm not, the ABI is extremely > tasteless and until you manage to document the exact semantics you want > for param->path, consider it NAKed. BTW, if that thing would be made to work, what's to stop somebody from doing ...at() syscalls with the resulting fd as a starting point and pathnames starting with ".."? "/foo is overmounted, but we can get to anything under /foo/bar/ in the underlying tree since there's an autofs mount somewhere in /foo/bar/splat/puke/*"? IOW, the real question (aside of "WTF?") is what are you using the resulting descriptor for and what do you need to be able to do with it. Details, please.