fscrypt: Use correct index in decrypt path.

Actually use the fs-provided index instead of always using page->index
which is only set for page-cache pages.

Fixes: 9c4bb8a3 ("fscrypt: Let fs select encryption index/tweak")
Signed-off-by: David Gstir <david@sigma-star.at>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

fs/crypto/crypto.c

@@ -296,7 +296,7 @@ EXPORT_SYMBOL(fscrypt_encrypt_page);
 int fscrypt_decrypt_page(const struct inode *inode, struct page *page,
 			unsigned int len, unsigned int offs, pgoff_t index)
 {
-	return do_page_crypto(inode, FS_DECRYPT, page->index, page, page, len, offs,
+	return do_page_crypto(inode, FS_DECRYPT, index, page, page, len, offs,
 			GFP_NOFS);
 }
 EXPORT_SYMBOL(fscrypt_decrypt_page);