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Commit 06497524 authored by J. Bruce Fields's avatar J. Bruce Fields
Browse files

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: default avatarJ. Bruce Fields <bfields@redhat.com>
parent c88739b3

net/sunrpc/cache.c

+20 −4
Original line number Diff line number Diff line
@@ -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.
@@ -1109,8 +1126,7 @@ 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) {

	if (!cache_listeners_exist(detail)) {

		warn_no_listener(detail);

		return -EINVAL;

	}