Re: squashfs seems nfs-incompatible

[Jan Engelhardt <jengelh@linux01.gwdg.de>]

Hi,

>> I found out that you cannot mount an exported squash fs. The exports(5) fsid=
>> parameter does not help it [like it did with unionfs].
>
>The exports(5) man page says fsid=num is necessary for filesystems on
>non-block devices - I don't know whether this includes loopback
>filesystems.  Have you tried exporting a Squashfs filesystem mounted
>on a real block device?

Loopback is a real block device, and no, fsid= does not help it. I have talked 
with the unionfs people, because it works for them. After a short flash of 
idea and comparison, it turns out that squashfs is missing 
sb->s_export->get_parent (the only requirement as it seems). Includes that you 
have sb->s_export non-null, of course. sb->s_export can be set within 
fill_super().

>I've never tried to export a Squashfs filesystem, and so I don't know
>if it works.  If it doesn't, I would say it is because Squashfs (like
>Cramfs) doesn't store correct nlink information for directories.
>
>The next release does store nlink information, has support for > 4GB
>files/filesystems, and other nice improvements.  I'm hoping to release
>an alpha release soon.

FTR, I currently cheated by using
`mount -t unionfs -o dirs=/squash=ro none /squash` to get the export working.



Jan Engelhardt
-- 
| Alphagate Systems, http://alphagate.hopto.org/
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