From f71c08ea8e60f035485a512fd2af8908567592f0 Mon Sep 17 00:00:00 2001 From: Pavel Butsykin Date: Mon, 18 Sep 2017 15:42:28 +0300 Subject: qcow2: add qcow2_cache_discard Whenever l2/refcount table clusters are discarded from the file we can automatically drop unnecessary content of the cache tables. This reduces the chance of eviction useful cache data and eliminates inconsistent data in the cache with the data in the file. Signed-off-by: Pavel Butsykin Reviewed-by: Max Reitz Reviewed-by: John Snow Message-id: 20170918124230.8152-3-pbutsykin@virtuozzo.com Signed-off-by: Max Reitz --- block/qcow2-refcount.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) (limited to 'block/qcow2-refcount.c') diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index 168fc32e7b..8c17c0e3aa 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -861,8 +861,24 @@ static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, } s->set_refcount(refcount_block, block_index, refcount); - if (refcount == 0 && s->discard_passthrough[type]) { - update_refcount_discard(bs, cluster_offset, s->cluster_size); + if (refcount == 0) { + void *table; + + table = qcow2_cache_is_table_offset(bs, s->refcount_block_cache, + offset); + if (table != NULL) { + qcow2_cache_put(bs, s->refcount_block_cache, &refcount_block); + qcow2_cache_discard(bs, s->refcount_block_cache, table); + } + + table = qcow2_cache_is_table_offset(bs, s->l2_table_cache, offset); + if (table != NULL) { + qcow2_cache_discard(bs, s->l2_table_cache, table); + } + + if (s->discard_passthrough[type]) { + update_refcount_discard(bs, cluster_offset, s->cluster_size); + } } } -- cgit v1.2.1