Commit be7e9858 authored Dec 12, 2012 by Jeff Layton Committed by Trond Myklebust Dec 12, 2012

nfs: fix page dirtying in NFS DIO read codepath



The NFS DIO code will dirty pages that catch read responses in order to
handle the case where someone is doing DIO reads into an mmapped buffer.
The existing code doesn't really do the right thing though since it
doesn't take into account the case where we might be attempting to read
past the EOF.

Fix the logic in that code to only dirty pages that ended up receiving
data from the read. Note too that it really doesn't matter if
NFS_IOHDR_ERROR is set or not. All that matters is if the page was
altered by the read.

Cc: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

parent 67fad106

fs/nfs/direct.c

+2 −7

Original line number	Original line	Diff line number	Diff line
	@@ -266,13 +266,8 @@ static void nfs_direct_read_completion(struct nfs_pgio_header *hdr)
	struct nfs_page *req = nfs_list_entry(hdr->pages.next);		struct nfs_page *req = nfs_list_entry(hdr->pages.next);
	struct page *page = req->wb_page;		struct page *page = req->wb_page;

	if (!PageCompound(page)) {		if (!PageCompound(page) && bytes < hdr->good_bytes)
	if (test_bit(NFS_IOHDR_ERROR, &hdr->flags)) {
	if (bytes < hdr->good_bytes)
	set_page_dirty(page);
	} else
	set_page_dirty(page);		set_page_dirty(page);
	}
	bytes += req->wb_bytes;		bytes += req->wb_bytes;
	nfs_list_remove_request(req);		nfs_list_remove_request(req);
	nfs_direct_readpage_release(req);		nfs_direct_readpage_release(req);

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