Add a test to make sure that we can handle multiple memory mappings to a
physical storage extent shared by multiple files, and that we can handle
the copy on write operation without error. Make sure we can also handle
mappings at different offsets in the page cache.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
Darrick J. Wong