From 06497524589f2a7717da33969d541674e0a27da6 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Sun, 19 Sep 2010 22:55:06 -0400 Subject: [PATCH] nfsd4: fix hang on fast-booting nfs servers The last_close field of a cache_detail is initialized to zero, so the condition detail->last_close < seconds_since_boot() - 30 may be false even for a cache that was never opened. However, we want to immediately fail upcalls to caches that were never opened: in the case of the auth_unix_gid cache, especially, which may never be opened by mountd (if the --manage-gids option is not set), we want to fail the upcall immediately. Otherwise client requests will be dropped unnecessarily on reboot. Also document these conditions. Signed-off-by: J. Bruce Fields --- net/sunrpc/cache.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c index da872f9fe1e0..ca7c621cd975 100644 --- a/net/sunrpc/cache.c +++ b/net/sunrpc/cache.c @@ -1091,6 +1091,23 @@ static void warn_no_listener(struct cache_detail *detail) } } +static bool cache_listeners_exist(struct cache_detail *detail) +{ + if (atomic_read(&detail->readers)) + return true; + if (detail->last_close == 0) + /* This cache was never opened */ + return false; + if (detail->last_close < seconds_since_boot() - 30) + /* + * We allow for the possibility that someone might + * restart a userspace daemon without restarting the + * server; but after 30 seconds, we give up. + */ + return false; + return true; +} + /* * register an upcall request to user-space and queue it up for read() by the * upcall daemon. @@ -1109,10 +1126,9 @@ int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h, char *bp; int len; - if (atomic_read(&detail->readers) == 0 && - detail->last_close < seconds_since_boot() - 30) { - warn_no_listener(detail); - return -EINVAL; + if (!cache_listeners_exist(detail)) { + warn_no_listener(detail); + return -EINVAL; } buf = kmalloc(PAGE_SIZE, GFP_KERNEL); -- 2.39.2