[LogFS] Remove h_version field

Incompatible change: h_compr is moved up so the padding is all in one chunk.

fs/logfs/journal.c

@@ -419,12 +419,13 @@ static size_t __logfs_write_header(struct logfs_super *super,
 {
 	jh->h_len	= cpu_to_be16(len);
 	jh->h_type	= cpu_to_be16(type);
-	jh->h_version	= cpu_to_be16(++super->s_last_version);
 	jh->h_datalen	= cpu_to_be16(datalen);
 	jh->h_compr	= compr;
 	jh->h_pad[0]	= 'H';
-	jh->h_pad[1]	= 'A';
-	jh->h_pad[2]	= 'T';
+	jh->h_pad[1]	= 'E';
+	jh->h_pad[2]	= 'A';
+	jh->h_pad[3]	= 'D';
+	jh->h_pad[4]	= 'R';
 	jh->h_crc	= logfs_crc32(jh, len + sizeof(*jh), 4);
 	return ALIGN(len, 16) + sizeof(*jh);
 }

fs/logfs/logfs_abi.h

@@ -422,7 +422,6 @@ SIZE_CHECK(logfs_segment_entry, 8);
  *				not including header
  * @h_datalen:			length of uncompressed data
  * @h_type:			JE type
- * @h_version:			unnormalized version of journal entry
  * @h_compr:			compression type
  * @h_pad:			reserved
  */
@@ -431,9 +430,8 @@ struct logfs_journal_header {
 	__be16	h_len;
 	__be16	h_datalen;
 	__be16	h_type;
-	__be16	h_version;
 	__u8	h_compr;
-	__u8	h_pad[3];
+	__u8	h_pad[5];
 };
 
 SIZE_CHECK(logfs_journal_header, 16);