sunrpc/cache: recheck cache validity after cache_defer_req
If cache_defer_req did not leave the request on a queue, then it could
possibly have waited long enough that the cache became valid. So check the
status after the call.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index 44f4516..bbd31f1 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -176,6 +176,22 @@
EXPORT_SYMBOL_GPL(sunrpc_cache_update);
static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h);
+
+static inline int cache_is_valid(struct cache_detail *detail, struct cache_head *h)
+{
+ if (!test_bit(CACHE_VALID, &h->flags) ||
+ h->expiry_time < get_seconds())
+ return -EAGAIN;
+ else if (detail->flush_time > h->last_refresh)
+ return -EAGAIN;
+ else {
+ /* entry is valid */
+ if (test_bit(CACHE_NEGATIVE, &h->flags))
+ return -ENOENT;
+ else
+ return 0;
+ }
+}
/*
* This is the generic cache management routine for all
* the authentication caches.
@@ -184,8 +200,10 @@
*
*
* Returns 0 if the cache_head can be used, or cache_puts it and returns
- * -EAGAIN if upcall is pending,
- * -ETIMEDOUT if upcall failed and should be retried,
+ * -EAGAIN if upcall is pending and request has been queued
+ * -ETIMEDOUT if upcall failed or request could not be queue or
+ * upcall completed but item is still invalid (implying that
+ * the cache item has been replaced with a newer one).
* -ENOENT if cache entry was negative
*/
int cache_check(struct cache_detail *detail,
@@ -195,17 +213,7 @@
long refresh_age, age;
/* First decide return status as best we can */
- if (!test_bit(CACHE_VALID, &h->flags) ||
- h->expiry_time < get_seconds())
- rv = -EAGAIN;
- else if (detail->flush_time > h->last_refresh)
- rv = -EAGAIN;
- else {
- /* entry is valid */
- if (test_bit(CACHE_NEGATIVE, &h->flags))
- rv = -ENOENT;
- else rv = 0;
- }
+ rv = cache_is_valid(detail, h);
/* now see if we want to start an upcall */
refresh_age = (h->expiry_time - h->last_refresh);
@@ -238,10 +246,14 @@
}
}
- if (rv == -EAGAIN)
- if (cache_defer_req(rqstp, h) != 0)
- rv = -ETIMEDOUT;
-
+ if (rv == -EAGAIN) {
+ if (cache_defer_req(rqstp, h) == 0) {
+ /* Request is not deferred */
+ rv = cache_is_valid(detail, h);
+ if (rv == -EAGAIN)
+ rv = -ETIMEDOUT;
+ }
+ }
if (rv)
cache_put(h, detail);
return rv;
@@ -560,11 +572,11 @@
* or continue and drop the oldest below
*/
if (net_random()&1)
- return -ETIMEDOUT;
+ return 0;
}
dreq = req->defer(req);
if (dreq == NULL)
- return -ETIMEDOUT;
+ return 0;
dreq->item = item;
@@ -594,8 +606,9 @@
if (!test_bit(CACHE_PENDING, &item->flags)) {
/* must have just been validated... */
cache_revisit_request(item);
+ return 0;
}
- return 0;
+ return 1;
}
static void cache_revisit_request(struct cache_head *item)