unmap_mapping_range — unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file.
|struct address_space * mapping,|
|loff_t const holebegin,|
|loff_t const holelen,|
struct address_space * mapping
the address space containing mmaps to be unmapped.
loff_t const holebegin
byte in first page to unmap, relative to the start of
the underlying file. This will be rounded down to a PAGE_SIZE
boundary. Note that this is different from
must keep the partial page. In contrast, we must get rid of
loff_t const holelen
size of prospective hole in bytes. This will be rounded up to a PAGE_SIZE boundary. A holelen of zero truncates to the end of the file.
1 when truncating a file, unmap even private COWed pages; but 0 when invalidating pagecache, don't throw away private data.