[PATCH 02/12] sunrpc/cache: make sure deferred requests eventually get revisited.

NeilBrown
2009-08-04T05:24:19Z

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 and upcall for that item. So when the upcall fails,
make sure to revisit all deferred requests.

Signed-off-by: NeilBrown <neilb@suse.de>
---

net/sunrpc/cache.c | 5 ++++-
1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index d19c075..44f4516 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);