nfs_write_end(): fix handling of short copies

[ Upstream commit c0cf3ef5e0f47e385920450b245d22bead93e7ad ]

What matters when deciding if we should make a page uptodate is
not how much we _wanted_ to copy, but how much we actually have
copied.  As it is, on architectures that do not zero tail on
short copy we can leave uninitialized data in page marked uptodate.

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 2ab6f00dba5bd63cc8e958165c1a5bdf9443840f..c85da0fc4593c99ca939d08c28157826e54575e5 100644 (file)
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -410,7 +410,7 @@ static int nfs_write_end(struct file *file, struct address_space *mapping,
         */
        if (!PageUptodate(page)) {
                unsigned pglen = nfs_page_length(page);
-               unsigned end = offset + len;
+               unsigned end = offset + copied;
 
                if (pglen == 0) {
                        zero_user_segments(page, 0, offset,