[Astlinux-devel] unionfs and Linux 3.16

[Lonnie A. <li...@lo...>]

Hi Devs,

First, it has been 10 days since we bumped the kernel to 3.16.43, and things appear to be running solid at this point, much thanks for all the assistance in getting this major task accomplished.

Though I ran across a glitch, with unionfs, basically you no longer can remove a *directory* in the path '/oldroot/mnt/asturw/...' as unionfs with kernel 3.16 has an issue with that.  Such a deletion now also effects open files in the same path, in memory.

Removing a *file* in the '/oldroot/mnt/asturw/...' path appears to be OK, which is important, since that is the only way to "undo" an edit of a file on '/oldroot/mnt/asturo/...'

I sent an email to Erez Zadok at Stony Brook University as well as the unionfs mailing list, where I go into more detail.

[Unionfs] unionfs with Linux 3.16
http://www.fsl.cs.sunysb.edu/pipermail/unionfs/2017-May/006196.html

I looked over our scripts and we only needed a few changes to implement the new rule:
--
Rule: Never remove a directory in the path '/oldroot/mnt/asturw/...' 
--
(Revision: 8361)

The 'show-union' command now only shows files, so as not to encourage directory removal, except 'show-union all' shows directories as well.

Any stale directories on ASTURW should not happen for normal users in production, but during development it can be handy to edit ASTURO files, so if you wanted to remove these stale directories (leaving them be is fine) you need to reboot to RUNNIX and mount /dev/sda2 as -t ext2.

Lonnie