Re: upcalls seem to have problems with symlinks, junctions et al.

[L A Walsh <cifs@tlinx.org>]

On 2/21/2019 8:30 PM, Steve French wrote:
> I have wanted to change this code and improve it for a while - one
> thing which is tricky is showing mode bits when no permissions to read
> permissions though, and we also need to clean up and simplify some of
> this code.   Let's follow up on this in a few days, if you are
> flexible and can install some test patches
>   
FWIW, it seems to be symlinks that are unreadable when perms on
the mount are set to 'multi-user'.
Using the following two examples from my system,

in cmd.exe they look like:
04/17/2017  08:45 AM    <SYMLINKD>     Share [S:\]
08/22/2018  03:08 PM    <JUNCTION>     Symbols [\\Bliss\Share\Symbols\]*
*

in Cygwin, they look like: (domain+user+groups are shortened to fit)
       (domain name, B (Bliss), username 'l' and group 'lg')
lrwxrwxrwx   1 B\l  B\lg  2 Apr 17  2017 Share -> /s
lrwxrwxrwx   1 B\l  B\lg 22 Aug 22  2018 Symbols -> //Bliss/Share/Symbols/

So both are links owned by me, one pointing to a locally mounted drive
and the other a remotely mounted Share on the Domain server.

On linux with single user mounting, I see:

l--------- 1 law Administrators            0 Apr 17  2017 Share -> /??/S://
drwxr-xr-x 2 law Administrators            0 Dec 17 19:14 Symbols/

Amusingly, I can read directory Symbols which results in a read
from the same server I'm doing the 'ls' from -- sorta the long way
around.

Oddly, I can't read the permissions on the symlink even though they
are usable (created directory named '??' and pointers and directories
underneath it as appropriate).

If I mount the cifs share "multiuser", I lose the capacity to see or
follow the symlinks as well as getting "Operation not supported" errors,
but the junctions still work fine:

ls: cannot access 'Share': Operation not supported
d????????? ? ?    ?                    ?            ? Share/
drwxrwxr-x 2 root Domain Admins        0 Dec 17 19:14 Symbols/

1) the Operation not supported message is dubious, since
I can read the link in single-user mount, even though the link
shows no access.

2) If the permissions on the links really are unreadable, the
'l-----' format is certainly easier on the eyes than
'd?????'.


I'd like to see the multi-user mount give at least as much information
as the single-user mount.  That would make sense, wouldn't it?
Can your patch/cleanup at least solve at problem?










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