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>

1 files changed, 4 insertions, 1 deletions

diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index d19c07583f8..44f45166378 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -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);