xref: /freebsd/tools/regression/nfsmmap/README (revision 6137b5f7b8c183ee8806d79b3f1d8e5e3ddb3df3)
1These tests are intended to make sure that NFS's use of the
2b_{valid,dirty}{off,end} fields of struct buf is consistent with the
3VM system's use of the underlying VM pages.
4
5Test1:
6	Open the file and write into the file, creating a buf
7	with a valid range and a dirty range
8
9	Fsync, flushing the dirty range
10
11	Mmap and read the whole page.  Since only part of the page is
12	valid, the VM system must re-read the invalid parts of the
13	page.
14
15Test2:
16	This is the same as test1 without the fsync.  The VM system
17	should first write out the dirty range and then read the rest
18	of the page.  This is currently broken since the vnode_pager
19	doesn't use the original buf for its i/o and therefore the
20	information in b_dirtyoff, b_dirtyend is not available.
21