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-rw-r--r--include/linux/sunrpc/cache.h16
-rw-r--r--net/sunrpc/cache.c53
2 files changed, 51 insertions, 18 deletions
diff --git a/include/linux/sunrpc/cache.h b/include/linux/sunrpc/cache.h
index 03d3b4c..ed03c9f 100644
--- a/include/linux/sunrpc/cache.h
+++ b/include/linux/sunrpc/cache.h
@@ -48,8 +48,10 @@
struct cache_head {
struct hlist_node cache_list;
time_t expiry_time; /* After time time, don't use the data */
- time_t last_refresh; /* If CACHE_PENDING, this is when upcall
- * was sent, else this is when update was received
+ time_t last_refresh; /* If CACHE_PENDING, this is when upcall was
+ * sent, else this is when update was
+ * received, though it is alway set to
+ * be *after* ->flush_time.
*/
struct kref ref;
unsigned long flags;
@@ -105,8 +107,12 @@ struct cache_detail {
/* fields below this comment are for internal use
* and should not be touched by cache owners
*/
- time_t flush_time; /* flush all cache items with last_refresh
- * earlier than this */
+ time_t flush_time; /* flush all cache items with
+ * last_refresh at or earlier
+ * than this. last_refresh
+ * is never set at or earlier
+ * than this.
+ */
struct list_head others;
time_t nextcheck;
int entries;
@@ -203,7 +209,7 @@ static inline void cache_put(struct cache_head *h, struct cache_detail *cd)
static inline int cache_is_expired(struct cache_detail *detail, struct cache_head *h)
{
return (h->expiry_time < seconds_since_boot()) ||
- (detail->flush_time > h->last_refresh);
+ (detail->flush_time >= h->last_refresh);
}
extern int cache_check(struct cache_detail *detail,
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index 4a2340a..5e4f815 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -41,13 +41,16 @@
static bool cache_defer_req(struct cache_req *req, struct cache_head *item);
static void cache_revisit_request(struct cache_head *item);
-static void cache_init(struct cache_head *h)
+static void cache_init(struct cache_head *h, struct cache_detail *detail)
{
time_t now = seconds_since_boot();
INIT_HLIST_NODE(&h->cache_list);
h->flags = 0;
kref_init(&h->ref);
h->expiry_time = now + CACHE_NEW_EXPIRY;
+ if (now <= detail->flush_time)
+ /* ensure it isn't already expired */
+ now = detail->flush_time + 1;
h->last_refresh = now;
}
@@ -81,7 +84,7 @@ struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail,
* we might get lose if we need to
* cache_put it soon.
*/
- cache_init(new);
+ cache_init(new, detail);
detail->init(new, key);
write_lock(&detail->hash_lock);
@@ -116,10 +119,15 @@ EXPORT_SYMBOL_GPL(sunrpc_cache_lookup);
static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch);
-static void cache_fresh_locked(struct cache_head *head, time_t expiry)
+static void cache_fresh_locked(struct cache_head *head, time_t expiry,
+ struct cache_detail *detail)
{
+ time_t now = seconds_since_boot();
+ if (now <= detail->flush_time)
+ /* ensure it isn't immediately treated as expired */
+ now = detail->flush_time + 1;
head->expiry_time = expiry;
- head->last_refresh = seconds_since_boot();
+ head->last_refresh = now;
smp_wmb(); /* paired with smp_rmb() in cache_is_valid() */
set_bit(CACHE_VALID, &head->flags);
}
@@ -149,7 +157,7 @@ struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
set_bit(CACHE_NEGATIVE, &old->flags);
else
detail->update(old, new);
- cache_fresh_locked(old, new->expiry_time);
+ cache_fresh_locked(old, new->expiry_time, detail);
write_unlock(&detail->hash_lock);
cache_fresh_unlocked(old, detail);
return old;
@@ -162,7 +170,7 @@ struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
cache_put(old, detail);
return NULL;
}
- cache_init(tmp);
+ cache_init(tmp, detail);
detail->init(tmp, old);
write_lock(&detail->hash_lock);
@@ -173,8 +181,8 @@ struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
hlist_add_head(&tmp->cache_list, &detail->hash_table[hash]);
detail->entries++;
cache_get(tmp);
- cache_fresh_locked(tmp, new->expiry_time);
- cache_fresh_locked(old, 0);
+ cache_fresh_locked(tmp, new->expiry_time, detail);
+ cache_fresh_locked(old, 0, detail);
write_unlock(&detail->hash_lock);
cache_fresh_unlocked(tmp, detail);
cache_fresh_unlocked(old, detail);
@@ -219,7 +227,8 @@ static int try_to_negate_entry(struct cache_detail *detail, struct cache_head *h
rv = cache_is_valid(h);
if (rv == -EAGAIN) {
set_bit(CACHE_NEGATIVE, &h->flags);
- cache_fresh_locked(h, seconds_since_boot()+CACHE_NEW_EXPIRY);
+ cache_fresh_locked(h, seconds_since_boot()+CACHE_NEW_EXPIRY,
+ detail);
rv = -ENOENT;
}
write_unlock(&detail->hash_lock);
@@ -487,10 +496,13 @@ EXPORT_SYMBOL_GPL(cache_flush);
void cache_purge(struct cache_detail *detail)
{
- detail->flush_time = LONG_MAX;
+ time_t now = seconds_since_boot();
+ if (detail->flush_time >= now)
+ now = detail->flush_time + 1;
+ /* 'now' is the maximum value any 'last_refresh' can have */
+ detail->flush_time = now;
detail->nextcheck = seconds_since_boot();
cache_flush();
- detail->flush_time = 1;
}
EXPORT_SYMBOL_GPL(cache_purge);
@@ -1436,6 +1448,7 @@ static ssize_t write_flush(struct file *file, const char __user *buf,
{
char tbuf[20];
char *bp, *ep;
+ time_t then, now;
if (*ppos || count > sizeof(tbuf)-1)
return -EINVAL;
@@ -1447,8 +1460,22 @@ static ssize_t write_flush(struct file *file, const char __user *buf,
return -EINVAL;
bp = tbuf;
- cd->flush_time = get_expiry(&bp);
- cd->nextcheck = seconds_since_boot();
+ then = get_expiry(&bp);
+ now = seconds_since_boot();
+ cd->nextcheck = now;
+ /* Can only set flush_time to 1 second beyond "now", or
+ * possibly 1 second beyond flushtime. This is because
+ * flush_time never goes backwards so it mustn't get too far
+ * ahead of time.
+ */
+ if (then >= now) {
+ /* Want to flush everything, so behave like cache_purge() */
+ if (cd->flush_time >= now)
+ now = cd->flush_time + 1;
+ then = now;
+ }
+
+ cd->flush_time = then;
cache_flush();
*ppos += count;
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