On 12.1.2023 г. 17:07, Jan Kara wrote:
So after a bit of thought I agree that the commit 5c48a7df91499 ("ext4: fix
an use-after-free issue about data=journal writeback mode") is broken. The
problem is when we unlock the page in __ext4_journalled_writepage() anybody
else can come, writeout the page, and reclaim page buffers (due to memory
pressure). Previously, bh references were preventing the buffer reclaim to
happen but now there's nothing to prevent it.
My rewrite of data=journal writeback path fixes this problem as a
side-effect but perhaps we need a quickfix for stable kernels? Something
like attached patch?
Honza
Do you consider this patch production ready?
Should we test it on real production machines with a peace of mind that
nothing can go wrong in regards to data loss or corruption?
--Ivan
