diff options
Diffstat (limited to 'drivers/md/bcache/btree.c')
-rw-r--r-- | drivers/md/bcache/btree.c | 53 |
1 files changed, 47 insertions, 6 deletions
diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c index 773f5fdad25f..ba434d9ac720 100644 --- a/drivers/md/bcache/btree.c +++ b/drivers/md/bcache/btree.c @@ -35,7 +35,7 @@ #include <linux/rcupdate.h> #include <linux/sched/clock.h> #include <linux/rculist.h> - +#include <linux/delay.h> #include <trace/events/bcache.h> /* @@ -613,6 +613,10 @@ static void mca_data_alloc(struct btree *b, struct bkey *k, gfp_t gfp) static struct btree *mca_bucket_alloc(struct cache_set *c, struct bkey *k, gfp_t gfp) { + /* + * kzalloc() is necessary here for initialization, + * see code comments in bch_btree_keys_init(). + */ struct btree *b = kzalloc(sizeof(struct btree), gfp); if (!b) @@ -655,7 +659,25 @@ static int mca_reap(struct btree *b, unsigned int min_order, bool flush) up(&b->io_mutex); } +retry: + /* + * BTREE_NODE_dirty might be cleared in btree_flush_btree() by + * __bch_btree_node_write(). To avoid an extra flush, acquire + * b->write_lock before checking BTREE_NODE_dirty bit. + */ mutex_lock(&b->write_lock); + /* + * If this btree node is selected in btree_flush_write() by journal + * code, delay and retry until the node is flushed by journal code + * and BTREE_NODE_journal_flush bit cleared by btree_flush_write(). + */ + if (btree_node_journal_flush(b)) { + pr_debug("bnode %p is flushing by journal, retry", b); + mutex_unlock(&b->write_lock); + udelay(1); + goto retry; + } + if (btree_node_dirty(b)) __bch_btree_node_write(b, &cl); mutex_unlock(&b->write_lock); @@ -778,10 +800,15 @@ void bch_btree_cache_free(struct cache_set *c) while (!list_empty(&c->btree_cache)) { b = list_first_entry(&c->btree_cache, struct btree, list); - if (btree_node_dirty(b)) + /* + * This function is called by cache_set_free(), no I/O + * request on cache now, it is unnecessary to acquire + * b->write_lock before clearing BTREE_NODE_dirty anymore. + */ + if (btree_node_dirty(b)) { btree_complete_write(b, btree_current_write(b)); - clear_bit(BTREE_NODE_dirty, &b->flags); - + clear_bit(BTREE_NODE_dirty, &b->flags); + } mca_data_free(b); } @@ -1067,11 +1094,25 @@ static void btree_node_free(struct btree *b) BUG_ON(b == b->c->root); +retry: mutex_lock(&b->write_lock); + /* + * If the btree node is selected and flushing in btree_flush_write(), + * delay and retry until the BTREE_NODE_journal_flush bit cleared, + * then it is safe to free the btree node here. Otherwise this btree + * node will be in race condition. + */ + if (btree_node_journal_flush(b)) { + mutex_unlock(&b->write_lock); + pr_debug("bnode %p journal_flush set, retry", b); + udelay(1); + goto retry; + } - if (btree_node_dirty(b)) + if (btree_node_dirty(b)) { btree_complete_write(b, btree_current_write(b)); - clear_bit(BTREE_NODE_dirty, &b->flags); + clear_bit(BTREE_NODE_dirty, &b->flags); + } mutex_unlock(&b->write_lock); |