| From | Herton Ronaldo Krzesinski <> | Subject | [PATCH 037/241] NFS: fix bug in legacy DNS resolver. | Date | Thu, 13 Dec 2012 11:56:42 -0200 |
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3.5.7.2 -stable review patch. If anyone has any objections, please let me know.
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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: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> --- 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 b3924b8..786cd65 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(); -- 1.7.9.5
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