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authorNeilBrown <neilb@suse.de>2012-10-31 12:16:01 +1100
committerTrond Myklebust <Trond.Myklebust@netapp.com>2012-10-31 16:25:59 -0400
commit8d96b10639fb402357b75b055b1e82a65ff95050 (patch)
tree13e1e4d63538e1f0177b64fee0b8ab7e96786089
parent2b1bc308f492589f7d49012ed24561534ea2be8c (diff)
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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 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> Cc: stable@vger.kernel.org Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
-rw-r--r--fs/nfs/dns_resolve.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/nfs/dns_resolve.c b/fs/nfs/dns_resolve.c
index 31c26c4dcc23..ca4b11ec87a2 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();