bcache: add code comments for journal_read_bucket() (2464b693) · Commits · 戴 / test

drivers/md/bcache/journal.c

+24 −0

Original line number	Diff line number	Diff line
		@@ -100,6 +100,20 @@ reread: left = ca->sb.bucket_size - offset;

		blocks = set_blocks(j, block_bytes(ca->set));

		/*
		* Nodes in 'list' are in linear increasing order of
		* i->j.seq, the node on head has the smallest (oldest)
		* journal seq, the node on tail has the biggest
		* (latest) journal seq.
		*/

		/*
		* Check from the oldest jset for last_seq. If
		* i->j.seq < j->last_seq, it means the oldest jset
		* in list is expired and useless, remove it from
		* this list. Otherwise, j is a condidate jset for
		* further following checks.
		*/
		while (!list_empty(list)) {
		i = list_first_entry(list,
		struct journal_replay, list);
		@@ -109,13 +123,22 @@ reread: left = ca->sb.bucket_size - offset;
		kfree(i);
		}

		/* iterate list in reverse order (from latest jset) */
		list_for_each_entry_reverse(i, list, list) {
		if (j->seq == i->j.seq)
		goto next_set;

		/*
		* if j->seq is less than any i->j.last_seq
		* in list, j is an expired and useless jset.
		*/
		if (j->seq < i->j.last_seq)
		goto next_set;

		/*
		* 'where' points to first jset in list which
		* is elder then j.
		*/
		if (j->seq > i->j.seq) {
		where = &i->list;
		goto add;
		@@ -129,6 +152,7 @@ add:
		if (!i)
		return -ENOMEM;
		memcpy(&i->j, j, bytes);
		/* Add to the location after 'where' points to */
		list_add(&i->list, where);
		ret = 1;