f2fs: add support for IV_INO_LBLK_64 encryption policies

f2fs inode numbers are stable across filesystem resizing, and f2fs inode
and file logical block numbers are always 32-bit.  So f2fs can always
support IV_INO_LBLK_64 encryption policies.  Wire up the needed
fscrypt_operations to declare support.
Acked-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>

fs/f2fs/super.c

@@ -2308,6 +2308,18 @@ static bool f2fs_dummy_context(struct inode *inode)
 	return DUMMY_ENCRYPTION_ENABLED(F2FS_I_SB(inode));
 }
 
+static bool f2fs_has_stable_inodes(struct super_block *sb)
+{
+	return true;
+}
+
+static void f2fs_get_ino_and_lblk_bits(struct super_block *sb,
+				       int *ino_bits_ret, int *lblk_bits_ret)
+{
+	*ino_bits_ret = 8 * sizeof(nid_t);
+	*lblk_bits_ret = 8 * sizeof(block_t);
+}
+
 static const struct fscrypt_operations f2fs_cryptops = {
 	.key_prefix		= "f2fs:",
 	.get_context		= f2fs_get_context,
@@ -2315,6 +2327,8 @@ static const struct fscrypt_operations f2fs_cryptops = {
 	.dummy_context		= f2fs_dummy_context,
 	.empty_dir		= f2fs_empty_dir,
 	.max_namelen		= F2FS_NAME_LEN,
+	.has_stable_inodes	= f2fs_has_stable_inodes,
+	.get_ino_and_lblk_bits	= f2fs_get_ino_and_lblk_bits,
 };
 #endif