[poky] Warning - don't use eCryptFS

[Paul Eggleton]

Hi all,

FYI I recently had some fairly serious problems with poky and the "encrypted home directory" function in Ubuntu, which uses eCryptFS. Problems I experienced included:

  * pseudo-native failing to write an sstate package ("file name too long" - apparently eCryptFS is limited to ~140 characters due to design limitations)

  * ncurses-native failing at do_install (some kind of interference with libtool that caused it to write an invalid path to the libncurses.la file, I didn't track down the exact cause as it went away when I stopped using eCryptFS. Might be indirectly related to the name length limitation.)

Scott, could you please add a warning to the documentation not to use eCryptFS with poky? In particular, it should not be used to store TMPDIR and SSTATE_DIR.

I'll follow up soon with a patch that will do a sanity check on the file name length limit - this will catch any other weird file systems that might cause these kinds of issues.

Cheers,
Paul