NFSv4.1: Fix an off-by-one error in pnfs_generic_pg_test

And document what is going on there...

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Trond Myklebust 2011-06-10 13:30:23 -04:00
parent 8f7d5efbef
commit 19982ba856

View File

@ -1078,11 +1078,22 @@ pnfs_generic_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
return true;
}
if (req_offset(req) > end_offset(pgio->pg_lseg->pls_range.offset,
pgio->pg_lseg->pls_range.length))
return false;
return true;
/*
* Test if a nfs_page is fully contained in the pnfs_layout_range.
* Note that this test makes several assumptions:
* - that the previous nfs_page in the struct nfs_pageio_descriptor
* is known to lie within the range.
* - that the nfs_page being tested is known to be contiguous with the
* previous nfs_page.
* - Layout ranges are page aligned, so we only have to test the
* start offset of the request.
*
* Please also note that 'end_offset' is actually the offset of the
* first byte that lies outside the pnfs_layout_range. FIXME?
*
*/
return req_offset(req) < end_offset(pgio->pg_lseg->pls_range.offset,
pgio->pg_lseg->pls_range.length);
}
EXPORT_SYMBOL_GPL(pnfs_generic_pg_test);