btrfs: send: explicitly number commands and attributes

Commit e77fbf99 ("btrfs: send: prepare for v2 protocol") added
_BTRFS_SEND_C_MAX_V* macros equal to the maximum command number for the
version plus 1, but as written this creates gaps in the number space.

The maximum command number is currently 22, and __BTRFS_SEND_C_MAX_V1 is
accordingly 23. But then __BTRFS_SEND_C_MAX_V2 is 24, suggesting that v2
has a command numbered 23, and __BTRFS_SEND_C_MAX is 25, suggesting that
23 and 24 are valid commands.

Instead, let's explicitly number all of the commands, attributes, and
sentinel MAX constants.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/send.c

@@ -333,8 +333,8 @@ __maybe_unused
 static bool proto_cmd_ok(const struct send_ctx *sctx, int cmd)
 {
 	switch (sctx->proto) {
-	case 1:	 return cmd < __BTRFS_SEND_C_MAX_V1;
-	case 2:	 return cmd < __BTRFS_SEND_C_MAX_V2;
+	case 1:	 return cmd <= BTRFS_SEND_C_MAX_V1;
+	case 2:	 return cmd <= BTRFS_SEND_C_MAX_V2;
 	default: return false;
 	}
 }

fs/btrfs/send.h

@@ -46,84 +46,82 @@ struct btrfs_tlv_header {
 
 /* commands */
 enum btrfs_send_cmd {
-	BTRFS_SEND_C_UNSPEC,
+	BTRFS_SEND_C_UNSPEC		= 0,
 
 	/* Version 1 */
-	BTRFS_SEND_C_SUBVOL,
-	BTRFS_SEND_C_SNAPSHOT,
+	BTRFS_SEND_C_SUBVOL		= 1,
+	BTRFS_SEND_C_SNAPSHOT		= 2,
 
-	BTRFS_SEND_C_MKFILE,
-	BTRFS_SEND_C_MKDIR,
-	BTRFS_SEND_C_MKNOD,
-	BTRFS_SEND_C_MKFIFO,
-	BTRFS_SEND_C_MKSOCK,
-	BTRFS_SEND_C_SYMLINK,
+	BTRFS_SEND_C_MKFILE		= 3,
+	BTRFS_SEND_C_MKDIR		= 4,
+	BTRFS_SEND_C_MKNOD		= 5,
+	BTRFS_SEND_C_MKFIFO		= 6,
+	BTRFS_SEND_C_MKSOCK		= 7,
+	BTRFS_SEND_C_SYMLINK		= 8,
 
-	BTRFS_SEND_C_RENAME,
-	BTRFS_SEND_C_LINK,
-	BTRFS_SEND_C_UNLINK,
-	BTRFS_SEND_C_RMDIR,
+	BTRFS_SEND_C_RENAME		= 9,
+	BTRFS_SEND_C_LINK		= 10,
+	BTRFS_SEND_C_UNLINK		= 11,
+	BTRFS_SEND_C_RMDIR		= 12,
 
-	BTRFS_SEND_C_SET_XATTR,
-	BTRFS_SEND_C_REMOVE_XATTR,
+	BTRFS_SEND_C_SET_XATTR		= 13,
+	BTRFS_SEND_C_REMOVE_XATTR	= 14,
 
-	BTRFS_SEND_C_WRITE,
-	BTRFS_SEND_C_CLONE,
+	BTRFS_SEND_C_WRITE		= 15,
+	BTRFS_SEND_C_CLONE		= 16,
 
-	BTRFS_SEND_C_TRUNCATE,
-	BTRFS_SEND_C_CHMOD,
-	BTRFS_SEND_C_CHOWN,
-	BTRFS_SEND_C_UTIMES,
+	BTRFS_SEND_C_TRUNCATE		= 17,
+	BTRFS_SEND_C_CHMOD		= 18,
+	BTRFS_SEND_C_CHOWN		= 19,
+	BTRFS_SEND_C_UTIMES		= 20,
 
-	BTRFS_SEND_C_END,
-	BTRFS_SEND_C_UPDATE_EXTENT,
-	__BTRFS_SEND_C_MAX_V1,
+	BTRFS_SEND_C_END		= 21,
+	BTRFS_SEND_C_UPDATE_EXTENT	= 22,
+	BTRFS_SEND_C_MAX_V1		= 22,
 
 	/* Version 2 */
-	__BTRFS_SEND_C_MAX_V2,
+	BTRFS_SEND_C_MAX_V2		= 22,
 
 	/* End */
-	__BTRFS_SEND_C_MAX,
+	BTRFS_SEND_C_MAX		= 22,
 };
-#define BTRFS_SEND_C_MAX (__BTRFS_SEND_C_MAX - 1)
 
 /* attributes in send stream */
 enum {
-	BTRFS_SEND_A_UNSPEC,
-
-	BTRFS_SEND_A_UUID,
-	BTRFS_SEND_A_CTRANSID,
-
-	BTRFS_SEND_A_INO,
-	BTRFS_SEND_A_SIZE,
-	BTRFS_SEND_A_MODE,
-	BTRFS_SEND_A_UID,
-	BTRFS_SEND_A_GID,
-	BTRFS_SEND_A_RDEV,
-	BTRFS_SEND_A_CTIME,
-	BTRFS_SEND_A_MTIME,
-	BTRFS_SEND_A_ATIME,
-	BTRFS_SEND_A_OTIME,
-
-	BTRFS_SEND_A_XATTR_NAME,
-	BTRFS_SEND_A_XATTR_DATA,
-
-	BTRFS_SEND_A_PATH,
-	BTRFS_SEND_A_PATH_TO,
-	BTRFS_SEND_A_PATH_LINK,
-
-	BTRFS_SEND_A_FILE_OFFSET,
-	BTRFS_SEND_A_DATA,
-
-	BTRFS_SEND_A_CLONE_UUID,
-	BTRFS_SEND_A_CLONE_CTRANSID,
-	BTRFS_SEND_A_CLONE_PATH,
-	BTRFS_SEND_A_CLONE_OFFSET,
-	BTRFS_SEND_A_CLONE_LEN,
-
-	__BTRFS_SEND_A_MAX,
+	BTRFS_SEND_A_UNSPEC		= 0,
+
+	BTRFS_SEND_A_UUID		= 1,
+	BTRFS_SEND_A_CTRANSID		= 2,
+
+	BTRFS_SEND_A_INO		= 3,
+	BTRFS_SEND_A_SIZE		= 4,
+	BTRFS_SEND_A_MODE		= 5,
+	BTRFS_SEND_A_UID		= 6,
+	BTRFS_SEND_A_GID		= 7,
+	BTRFS_SEND_A_RDEV		= 8,
+	BTRFS_SEND_A_CTIME		= 9,
+	BTRFS_SEND_A_MTIME		= 10,
+	BTRFS_SEND_A_ATIME		= 11,
+	BTRFS_SEND_A_OTIME		= 12,
+
+	BTRFS_SEND_A_XATTR_NAME		= 13,
+	BTRFS_SEND_A_XATTR_DATA		= 14,
+
+	BTRFS_SEND_A_PATH		= 15,
+	BTRFS_SEND_A_PATH_TO		= 16,
+	BTRFS_SEND_A_PATH_LINK		= 17,
+
+	BTRFS_SEND_A_FILE_OFFSET	= 18,
+	BTRFS_SEND_A_DATA		= 19,
+
+	BTRFS_SEND_A_CLONE_UUID		= 20,
+	BTRFS_SEND_A_CLONE_CTRANSID	= 21,
+	BTRFS_SEND_A_CLONE_PATH		= 22,
+	BTRFS_SEND_A_CLONE_OFFSET	= 23,
+	BTRFS_SEND_A_CLONE_LEN		= 24,
+
+	BTRFS_SEND_A_MAX		= 24,
 };
-#define BTRFS_SEND_A_MAX (__BTRFS_SEND_A_MAX - 1)
 
 #ifdef __KERNEL__
 long btrfs_ioctl_send(struct inode *inode, struct btrfs_ioctl_send_args *arg);