ceph: promote to unsigned long long before shifting

On 32-bit systems, this shift will overflow for files larger than 4GB.

Cc: stable@vger.kernel.org
Fixes: 61f68816 ("ceph: check caps in filemap_fault and page_mkwrite")
Signed-off-by: NMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: NJeff Layton <jlayton@kernel.org>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

fs/ceph/addr.c

@@ -1471,7 +1471,7 @@ static vm_fault_t ceph_filemap_fault(struct vm_fault *vmf)
 	struct ceph_inode_info *ci = ceph_inode(inode);
 	struct ceph_file_info *fi = vma->vm_file->private_data;
 	struct page *pinned_page = NULL;
-	loff_t off = vmf->pgoff << PAGE_SHIFT;
+	loff_t off = (loff_t)vmf->pgoff << PAGE_SHIFT;
 	int want, got, err;
 	sigset_t oldset;
 	vm_fault_t ret = VM_FAULT_SIGBUS;