From: Coly Li Date: Wed, 13 Nov 2019 08:03:22 +0000 (+0800) Subject: bcache: add code comments in bch_btree_leaf_dirty() X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=5dccefd3ea0b33cf3e5a45cbccc7e0bf22791655;p=linux.git bcache: add code comments in bch_btree_leaf_dirty() This patch adds code comments in bch_btree_leaf_dirty() to explain why w->journal should always reference the eldest journal pin of all the writing bkeys in the btree node. To make the bcache journal code to be easier to be understood. Signed-off-by: Coly Li Signed-off-by: Jens Axboe --- diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c index 39d7fc1ef1eeb..48e33ee0d8761 100644 --- a/drivers/md/bcache/btree.c +++ b/drivers/md/bcache/btree.c @@ -569,6 +569,11 @@ static void bch_btree_leaf_dirty(struct btree *b, atomic_t *journal_ref) set_btree_node_dirty(b); + /* + * w->journal is always the oldest journal pin of all bkeys + * in the leaf node, to make sure the oldest jset seq won't + * be increased before this btree node is flushed. + */ if (journal_ref) { if (w->journal && journal_pin_cmp(b->c, w->journal, journal_ref)) {