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authorNeilBrown <neilb@suse.de>2012-10-31 12:16:01 +1100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-11-17 13:16:12 -0800
commit088eb1bed178645788538611ac31ba9991cd88c4 (patch)
treeee637ef3a4b53b4c4f25605865ed6a252de15105
parent588c72e88125b1abe50efb3f1b6b768b98302e2c (diff)
NFS: fix bug in legacy DNS resolver.
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>
-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 b3924b8a6000..786cd6533713 100644
--- a/fs/nfs/dns_resolve.c
+++ b/fs/nfs/dns_resolve.c
@@ -214,7 +214,7 @@ 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;
@@ -237,7 +237,8 @@ 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();