f2fs crypto: sync with ext4's fname padding

This patch fixes wrong adoption on fname padding.
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/crypto_fname.c

@@ -267,13 +267,13 @@ int f2fs_fname_crypto_alloc_buffer(struct inode *inode,
 				   u32 ilen, struct f2fs_str *crypto_str)
 {
 	unsigned int olen;
-	int padding = 16;
+	int padding = 32;
 	struct f2fs_crypt_info *ci = F2FS_I(inode)->i_crypt_info;
 
 	if (ci)
 		padding = 4 << (ci->ci_flags & F2FS_POLICY_FLAGS_PAD_MASK);
-	if (padding < F2FS_CRYPTO_BLOCK_SIZE)
-		padding = F2FS_CRYPTO_BLOCK_SIZE;
+	if (ilen < F2FS_CRYPTO_BLOCK_SIZE)
+		ilen = F2FS_CRYPTO_BLOCK_SIZE;
 	olen = f2fs_fname_crypto_round_up(ilen, padding);
 	crypto_str->len = olen;
 	if (olen < F2FS_FNAME_CRYPTO_DIGEST_SIZE * 2)