From 8e61209c67bd524b43c0a0e0e73ddde6f141b062 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Wed, 31 Oct 2012 12:16:01 +1100 Subject: [PATCH] NFS: fix bug in legacy DNS resolver. The DNS resolver's use of the sunrpc cache involves a 'ttl' number (relative) rather that a timeout (absolute). This confused me when I wrote commit e7a3b74882633a3ea1f56572de8c4a7be52f5873 "sunrpc: use seconds since boot in expiry cache" and I managed to break it. The effect is that any TTL is interpreted as 0, and nothing useful gets into the cache. This patch removes the use of get_expiry() - which really expects an expiry time - and uses get_uint() instead, treating the int correctly as a ttl. This fixes a regression that has been present since 2.6.37, causing certain NFS accesses in certain environments to incorrectly fail. Reported-by: Chuck Lever Tested-by: Chuck Lever Cc: stable@vger.kernel.org Signed-off-by: NeilBrown Signed-off-by: Trond Myklebust --- fs/nfs/dns_resolve.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/nfs/dns_resolve.c b/fs/nfs/dns_resolve.c index 31c26c4dcc238..ca4b11ec87a29 100644 --- a/fs/nfs/dns_resolve.c +++ b/fs/nfs/dns_resolve.c @@ -217,7 +217,7 @@ static int nfs_dns_parse(struct cache_detail *cd, char *buf, int buflen) { char buf1[NFS_DNS_HOSTNAME_MAXLEN+1]; struct nfs_dns_ent key, *item; - unsigned long ttl; + unsigned int ttl; ssize_t len; int ret = -EINVAL; @@ -240,7 +240,8 @@ static int nfs_dns_parse(struct cache_detail *cd, char *buf, int buflen) key.namelen = len; memset(&key.h, 0, sizeof(key.h)); - ttl = get_expiry(&buf); + if (get_uint(&buf, &ttl) < 0) + goto out; if (ttl == 0) goto out; key.h.expiry_time = ttl + seconds_since_boot(); -- 2.39.5