Re: [RFC PATCH v3 03/12] fs: add RWF_ENCODED for reading/writing compressed data

On Tue, Nov 26, 2019 at 03:53:02PM +0200, Nikolay Borisov wrote:

On 20.11.19 г. 20:24 ч., Omar Sandoval wrote:

quoted

From: Omar Sandoval <redacted>

<snip>

quoted

 
+enum {
+	ENCODED_IOV_COMPRESSION_NONE,
+#define ENCODED_IOV_COMPRESSION_NONE ENCODED_IOV_COMPRESSION_NONE
+	ENCODED_IOV_COMPRESSION_ZLIB,
+#define ENCODED_IOV_COMPRESSION_ZLIB ENCODED_IOV_COMPRESSION_ZLIB
+	ENCODED_IOV_COMPRESSION_LZO,
+#define ENCODED_IOV_COMPRESSION_LZO ENCODED_IOV_COMPRESSION_LZO
+	ENCODED_IOV_COMPRESSION_ZSTD,
+#define ENCODED_IOV_COMPRESSION_ZSTD ENCODED_IOV_COMPRESSION_ZSTD
+	ENCODED_IOV_COMPRESSION_TYPES = ENCODED_IOV_COMPRESSION_ZSTD,

This looks very dodgy, what am I missing?

This is a somewhat common trick so that enum values can be checked for
with ifdef/ifndef. See include/uapi/linux.in.h, for example.