sunrpc/cache: make sure deferred requests eventually get revisited.

While deferred requests normally get revisited quite quickly,
it is possible for a request to remain in the deferral queue
when the cache item is discarded.  We can easily make sure that
doesn't happen by calling cache_revisit_request just before
the final 'put'.

Also there is a small chance that a race would cause one thread to
defer a request against a cache item while another thread is failing
to queue an upcall for that item.  So when the upcall fails, make
sure to revisit all deferred requests.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
This commit is contained in:
NeilBrown 2009-08-04 15:22:38 +10:00 committed by J. Bruce Fields
parent f866a8194f
commit 5c4d263903

View File

@ -221,6 +221,7 @@ int cache_check(struct cache_detail *detail,
switch (cache_make_upcall(detail, h)) {
case -EINVAL:
clear_bit(CACHE_PENDING, &h->flags);
cache_revisit_request(h);
if (rv == -EAGAIN) {
set_bit(CACHE_NEGATIVE, &h->flags);
cache_fresh_unlocked(h, detail,
@ -473,8 +474,10 @@ static int cache_clean(void)
if (!ch)
current_index ++;
spin_unlock(&cache_list_lock);
if (ch)
if (ch) {
cache_revisit_request(ch);
cache_put(ch, d);
}
} else
spin_unlock(&cache_list_lock);