generic: test DAX DMA vs truncate/hole-punch
This adds a regression test for the following series:
[PATCH v4 0/2] ext4: fix DAX dma vs truncate/hole-punch
https://lists.01.org/pipermail/linux-nvdimm/2018-July/016842.html
which adds synchronization between DAX DMA in ext4 and truncate/hole-punch.
The intention of the test is to test those specific changes, but it runs
fine both with XFS and without DAX so I've put it in the generic tests
instead of ext4 and not restricted it to only DAX configurations.
When run with v4.18-rc6 + DAX + ext4, this test will hit the following
WARN_ON_ONCE() in dax_disassociate_entry():
WARN_ON_ONCE(trunc && page_ref_count(page) > 1);
If you change this to a WARN_ON() instead, you can see that each of the
four paths being exercised in this test hits that condition many times in
the one second that the subtest is being run.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
6 files changed
