Trond points out in commit
277f27e2f277 ("SUNRPC/cache: Allow
garbage collection of invalid cache entries") that we allow invalid
cache entries to persist indefinitely. That fix, however,
reintroduces the problem fixed by Kinglong Mee's commit
d6fc8821c2d2
("SUNRPC/Cache: Always treat the invalid cache as unexpired"), where
an invalid cache entry is immediately removed by a flush before
mountd responds to it. The result is that the server thread that
should be waiting for mountd to fill in that entry instead gets an
-ETIMEDOUT return from cache_check(). Symptoms are the server
becoming unresponsive after a restart, reproduceable by running
pynfs 4.1 test REBT5.
Instead, take a compromise approach: allow invalid cache entries to
be removed after they expire, but not to be removed by a cache
flush.
Fixes:
277f27e2f277 ("SUNRPC/cache: Allow garbage collection ... ")
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
static inline bool cache_is_expired(struct cache_detail *detail, struct cache_head *h)
{
- return (h->expiry_time < seconds_since_boot()) ||
- (detail->flush_time >= h->last_refresh);
+ if (h->expiry_time < seconds_since_boot())
+ return true;
+ if (!test_bit(CACHE_VALID, &h->flags))
+ return false;
+ return detail->flush_time >= h->last_refresh;
}
extern int cache_check(struct cache_detail *detail,