scoutfs-utils: calculate segment crc in mkfs

Signed-off-by: Zach Brown <zab@versity.com>

utils/src/crc.c

@@ -37,3 +37,12 @@ u32 crc_block(struct scoutfs_block_header *hdr)
 	return crc32c(~0, (char *)hdr + sizeof(hdr->crc),
 		      SCOUTFS_BLOCK_SIZE - sizeof(hdr->crc));
 }
+
+u32 crc_segment(struct scoutfs_segment_block *sblk)
+{
+	u32 off = offsetof(struct scoutfs_segment_block, _padding) +
+		  sizeof(sblk->_padding);
+
+	return crc32c(~0, (char *)sblk + off,
+		      le32_to_cpu(sblk->total_bytes) - off);
+}

utils/src/crc.h

@@ -8,5 +8,6 @@
 u32 crc32c(u32 crc, const void *data, unsigned int len);
 u64 crc32c_64(u32 crc, const void *data, unsigned int len);
 u32 crc_block(struct scoutfs_block_header *hdr);
+u32 crc_segment(struct scoutfs_segment_block *seg);
 
 #endif

utils/src/format.h

@@ -271,6 +271,9 @@ struct scoutfs_segment_item {
 /*
  * Each large segment starts with a segment block that describes the
  * rest of the blocks that make up the segment.
+ *
+ * The crc covers the initial total_bytes of the segment but starts
+ * after the padding.
  */
 struct scoutfs_segment_block {
 	__le32 crc;

utils/src/mkfs.c

@@ -377,6 +377,7 @@ static int write_new_fs(char *path, int fd)
 
 	item = (void *)(inode + 1);
 	sblk->total_bytes = cpu_to_le32((long)item - (long)sblk);
+	sblk->crc = cpu_to_le32(crc_segment(sblk));
 
 	ret = pwrite(fd, sblk, SCOUTFS_SEGMENT_SIZE,
 		     first_segno << SCOUTFS_SEGMENT_SHIFT);