generic: add regression test for stale mmap reads
This adds a regression test for the following kernel patch:
dax: fix data corruption due to stale mmap reads
The above patch fixes an issue where users of DAX can suffer data
corruption from stale mmap reads via the following sequence:
- open an mmap over a 2MiB hole
- read from a 2MiB hole, faulting in a 2MiB zero page
- write to the hole with write(3p). The write succeeds but we incorrectly
leave the 2MiB zero page mapping intact.
- via the mmap, read the data that was just written. Since the zero page
mapping is still intact we read back zeroes instead of the new data.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>
6 files changed
