Backport microdesc_cache_clean to 0.2.2

Otherwise we have no way to keep authorities' microdesc caches in 0.2.2
from growing without bound.
This commit is contained in:
Nick Mathewson 2011-05-03 16:45:15 -04:00
parent 970715dd8f
commit 56fbd728c2
3 changed files with 56 additions and 0 deletions

4
changes/bug2230_clean_1 Normal file
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@ -0,0 +1,4 @@
o Minor features
- Backport code from 0.2.3.x to allow directory authorities to clean
their microdescriptor caches.

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@ -23,6 +23,8 @@ struct microdesc_cache_t {
tor_mmap_t *cache_content;
/** Number of bytes used in the journal file. */
size_t journal_len;
/** Number of bytes in descriptors removed as too old. */
size_t bytes_dropped;
/** Total bytes of microdescriptor bodies we have added to this cache */
uint64_t total_len_seen;
@ -276,6 +278,51 @@ microdesc_cache_reload(microdesc_cache_t *cache)
return 0;
}
/** By default, we remove any microdescriptors that have gone at least this
* long without appearing in a current consensus. */
#define TOLERATE_MICRODESC_AGE (7*24*60*60)
/** Remove all microdescriptors from <b>cache</b> that haven't been listed for
* a long time. Does not rebuild the cache on disk. If <b>cutoff</b> is
* positive, specifically remove microdescriptors that have been unlisted
* since <b>cutoff</b>. If <b>force</b> is true, remove microdescriptors even
* if we have no current live microdescriptor consensus.
*/
void
microdesc_cache_clean(microdesc_cache_t *cache, time_t cutoff, int force)
{
microdesc_t **mdp, *victim;
int dropped=0, kept=0;
size_t bytes_dropped = 0;
time_t now = time(NULL);
(void) force;
/* In 0.2.2, we let this proceed unconditionally: only authorities have
* microdesc caches. */
if (cutoff <= 0)
cutoff = now - TOLERATE_MICRODESC_AGE;
for (mdp = HT_START(microdesc_map, &cache->map); mdp != NULL; ) {
if ((*mdp)->last_listed < cutoff) {
++dropped;
victim = *mdp;
mdp = HT_NEXT_RMV(microdesc_map, &cache->map, mdp);
bytes_dropped += victim->bodylen;
microdesc_free(victim);
} else {
++kept;
mdp = HT_NEXT(microdesc_map, &cache->map, mdp);
}
}
if (dropped) {
log_notice(LD_DIR, "Removed %d/%d microdescriptors as old.",
dropped,dropped+kept);
cache->bytes_dropped += bytes_dropped;
}
}
/** Regenerate the main cache file for <b>cache</b>, clear the journal file,
* and update every microdesc_t in the cache with pointers to its new
* location. */
@ -291,6 +338,10 @@ microdesc_cache_rebuild(microdesc_cache_t *cache)
int orig_size, new_size;
log_info(LD_DIR, "Rebuilding the microdescriptor cache...");
/* Remove dead descriptors */
microdesc_cache_clean(cache, 0/*cutoff*/, 0/*force*/);
orig_size = (int)(cache->cache_content ? cache->cache_content->size : 0);
orig_size += (int)cache->journal_len;

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@ -21,6 +21,7 @@ smartlist_t *microdescs_add_list_to_cache(microdesc_cache_t *cache,
smartlist_t *descriptors, saved_location_t where,
int no_save);
void microdesc_cache_clean(microdesc_cache_t *cache, time_t cutoff, int force);
int microdesc_cache_rebuild(microdesc_cache_t *cache);
int microdesc_cache_reload(microdesc_cache_t *cache);
void microdesc_cache_clear(microdesc_cache_t *cache);