SRU for Oneiric and Precise, and please apply to Quantal too.
== SRU Justification ==
== Impact ==
A regression was caused by commit:
821f749 eCryptfs: Revert to a writethrough cache model
That patch reverted some code (specifically, 32001d6f) that was
necessary to properly handle open() -> mmap() -> close() -> dirty pages
-> munmap(), because the lower file could be closed before the dirty
pages are written out.
This revert unfortunately causes errors:
ecryptfs_encrypt_page: Error attempting to write lower page
== Fix ==
Apply commits 7149f2558d5b5b988726662fe58b1c388337805b and
== Test Case ==
Can be tested on various file systems using the ecryptfs tests (from