Log block chaining. More...

#include <zil.h>

Collaboration diagram for zil_chain:

Data Fields
uint64_t	zc_pad
blkptr_t	zc_next_blk
	next block in chain
uint64_t	zc_nused
	bytes in log block used
zio_eck_t	zc_eck
	block trailer

Detailed Description

Log block chaining.

Log blocks are chained together. Originally they were chained at the end of the block. For performance reasons the chain was moved to the beginning of the block which allows writes for only the data being used. The older position is supported for backwards compatability.

The zio_eck_t contains a zec_cksum which for the intent log is the sequence number of this log block. A seq of 0 is invalid. The zec_cksum is checked by the SPA against the sequence number passed in the blk_cksum field of the blkptr_t

Definition at line 90 of file zil.h.