Re: [PATCH] mount: Do not call mnt_pretty_path() on net file systems.

[Karel Zak <kzak@redhat.com>]

On Tue, Feb 19, 2019 at 04:50:26PM +0100, Stanislav Brabec wrote:
> Dne 06. 02. 19 v 11:58 Karel Zak napsal(a):
> > On Wed, Feb 06, 2019 at 12:07:54AM +0100, Stanislav Brabec wrote:
> >>  sys-utils/mount.c | 2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > Applied, thanks!
> > 
> > Please, send also updates for the mnt_fstype_is_pseudofs().
> > 
> 
> I started to inspect file systems available in SUSE, and I found
> that there is an another category of file systems: File systems that
> have a source (so they are not pseudo file systems), but information
> provided by the kernel is not sufficient to check whether a
> particular source is already mounted.
> 
> Some of them are completely undetectable (both source and FS type
> provide generic information only), some are detectable by source,
> but not by FS type, some are detectable by FS type, but source match
> cannot be used.
> 
> For these file systems, mount(8) cannot guarantee that the correct
> volume is mounted. Only some guesses are possible.

The question is how critical is it for us... maybe all we need is to
document mount(8) limitations for these cases.

> Maybe it should warn about it, or it should refuse such file systems in the fstab.
> 
> 
> Examples of undetectable FUSE file systems:
> 
> xdg-document-portal is completely undetectable; it can be ran once per UID
> /dev/fuse on /run/user/10027/doc type fuse (rw,nosuid,nodev,relatime,user_id=10027,group_id=100)
> 376 536 0:65 / /run/user/10027/doc rw,nosuid,nodev,relatime - fuse /dev/fuse rw,user_id=10027,group_id=100

No subtype ? How FUSE driver redirects it to the right code?

> 
> curlftpfs undetectable by type, detectable by source
> curlftpfs#ftp://ftp.suse.com/ on /home/sbrabec/T type fuse (rw,nosuid,nodev,relatime,user_id=10027,group_id=100)
> 544 510 0:47 / /sys/fs/fuse/connections rw,relatime master:282 - fusectl fusectl rw

 "subtype#" is deprecated; I guess fuse.curlftpfs has to work ;-)

    Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com