| From 8d96b10639fb402357b75b055b1e82a65ff95050 Mon Sep 17 00:00:00 2001 |
| From: NeilBrown <neilb@suse.de> |
| Date: Wed, 31 Oct 2012 12:16:01 +1100 |
| Subject: NFS: fix bug in legacy DNS resolver. |
| |
| From: NeilBrown <neilb@suse.de> |
| |
| commit 8d96b10639fb402357b75b055b1e82a65ff95050 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 c5b29f885afe890f953f7f23424045cdad31d3e4 |
| "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 <chuck.lever@oracle.com> |
| Tested-by: Chuck Lever <chuck.lever@oracle.com> |
| Signed-off-by: NeilBrown <neilb@suse.de> |
| Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| fs/nfs/dns_resolve.c | 5 +++-- |
| 1 file changed, 3 insertions(+), 2 deletions(-) |
| |
| --- a/fs/nfs/dns_resolve.c |
| +++ b/fs/nfs/dns_resolve.c |
| @@ -213,7 +213,7 @@ static int nfs_dns_parse(struct cache_de |
| { |
| 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; |
| |
| @@ -236,7 +236,8 @@ static int nfs_dns_parse(struct cache_de |
| 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(); |
