Commit 0a616792 authored by NeilBrown's avatar NeilBrown Committed by Ben Hutchings

NFS: fix bug in legacy DNS resolver.

commit 8d96b106 upstream.

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 c5b29f88
     "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: default avatarChuck Lever <chuck.lever@oracle.com>
Tested-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
parent 4360e736
...@@ -213,7 +213,7 @@ static int nfs_dns_parse(struct cache_detail *cd, char *buf, int buflen) ...@@ -213,7 +213,7 @@ static int nfs_dns_parse(struct cache_detail *cd, char *buf, int buflen)
{ {
char buf1[NFS_DNS_HOSTNAME_MAXLEN+1]; char buf1[NFS_DNS_HOSTNAME_MAXLEN+1];
struct nfs_dns_ent key, *item; struct nfs_dns_ent key, *item;
unsigned long ttl; unsigned int ttl;
ssize_t len; ssize_t len;
int ret = -EINVAL; int ret = -EINVAL;
...@@ -236,7 +236,8 @@ static int nfs_dns_parse(struct cache_detail *cd, char *buf, int buflen) ...@@ -236,7 +236,8 @@ static int nfs_dns_parse(struct cache_detail *cd, char *buf, int buflen)
key.namelen = len; key.namelen = len;
memset(&key.h, 0, sizeof(key.h)); memset(&key.h, 0, sizeof(key.h));
ttl = get_expiry(&buf); if (get_uint(&buf, &ttl) < 0)
goto out;
if (ttl == 0) if (ttl == 0)
goto out; goto out;
key.h.expiry_time = ttl + seconds_since_boot(); key.h.expiry_time = ttl + seconds_since_boot();
......
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