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authorPavel Butsykin <pbutsykin@virtuozzo.com>2017-09-18 15:42:28 +0300
committerMax Reitz <mreitz@redhat.com>2017-09-26 15:00:32 +0200
commitf71c08ea8e60f035485a512fd2af8908567592f0 (patch)
treea3ef8dc5e1f34e1a18d755672029bced057885ba /block/qcow2-cache.c
parent4ffca8904a350460cdaa6304ea8c9b9c693d2d91 (diff)
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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 <pbutsykin@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Message-id: 20170918124230.8152-3-pbutsykin@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'block/qcow2-cache.c')
-rw-r--r--block/qcow2-cache.c26
1 files changed, 26 insertions, 0 deletions
diff --git a/block/qcow2-cache.c b/block/qcow2-cache.c
index 1d25147..75746a7 100644
--- a/block/qcow2-cache.c
+++ b/block/qcow2-cache.c
@@ -411,3 +411,29 @@ void qcow2_cache_entry_mark_dirty(BlockDriverState *bs, Qcow2Cache *c,
assert(c->entries[i].offset != 0);
c->entries[i].dirty = true;
}
+
+void *qcow2_cache_is_table_offset(BlockDriverState *bs, Qcow2Cache *c,
+ uint64_t offset)
+{
+ int i;
+
+ for (i = 0; i < c->size; i++) {
+ if (c->entries[i].offset == offset) {
+ return qcow2_cache_get_table_addr(bs, c, i);
+ }
+ }
+ return NULL;
+}
+
+void qcow2_cache_discard(BlockDriverState *bs, Qcow2Cache *c, void *table)
+{
+ int i = qcow2_cache_get_table_idx(bs, c, table);
+
+ assert(c->entries[i].ref == 0);
+
+ c->entries[i].offset = 0;
+ c->entries[i].lru_counter = 0;
+ c->entries[i].dirty = false;
+
+ qcow2_cache_table_release(bs, c, i, 1);
+}