Bug 53205

Summary:	mount should support bind mount with new options
Product:	systemd	Reporter:	Edward Z. Yang <ezyang>
Component:	general	Assignee:	systemd-bugs
Status:	RESOLVED NOTOURBUG	QA Contact:	systemd-bugs
Severity:	normal
Priority:	medium	CC:	gustavo
Version:	unspecified
Hardware:	Other
OS:	All
Whiteboard:
i915 platform:		i915 features:

Description Edward Z. Yang 2012-08-07 10:17:16 UTC

systemd doesn't really understand how to do bind mounts with new options. Right now, we can do:

[Mount]
What=/var/lib/mock
Where=/var/lib/mock
Type=none
Options=bind,nosuid

But this translates into:

mount /var/lib/mock /var/lib/mock -t none -o bind,nosuid

rather than the correct sequence:

mount /var/lib/mock /var/lib/mock -o bind
mount -o remount,nosuid /var/lib/mock

since mount doesn't support bind-mounting plus extra options (this is documented in the manpage). It would be nice if systemd could apply some magic here and make it work.

(Note you can't even make two mounts, because systemd's naming convention means only one unit file can be specified per mountpoint.)

Comment 1 Andrew Walrond 2012-08-14 20:50:52 UTC

Yes this bit me also, but I'm using fstab entries like this:

LABEL=var  /var   auto  defaults,relatime  0  1
/var/home  /home  none  bind,noatime,auto  0  0

/home does not get mounted noatime until I do

mount -o remount,bind

after boot.

So a big +1 from me for fixing this.

Karel Zak (util-linux maintainer) explains this stuff nicely in the context of the 'ro' attribute on his blog

http://karelzak.blogspot.co.uk/2011/04/bind-mounts-mtab-and-read-only.html

Comment 2 Lennart Poettering 2013-01-15 01:24:55 UTC

I am pretty sure should probably get this fixed in the kernel, so that we can actually create the bind mounts atomically. It's less than ideal if everybody sees two mount events and when apps react to that (such as nautilus and gvfs) they will first see a mount point with incorrect mount options...

Comment 3 Lennart Poettering 2014-06-25 09:26:07 UTC

Closing, this should either be fixed in the kernel (ideally) or in util-linux' mount command. We shouldn't work around it in systemd.

Comment 4 Christian Seiler 2015-02-21 13:04:51 UTC

In case anybody stumbles over this problem, I've devised a possible
workaround until there's a proper fix for this issue:
https://blog.iwakd.de/systemd-fstab-and-bind-mounts-with-options

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