From: Paulo Alcantara pc@cjr.nz
commit 4ac0536f8874a903a72bddc57eb88db774261e3a upstream.
With commit 506c1da44fee ("cifs: use the expiry output of dns_query to schedule next resolution") and after triggering the first reconnect, the next async dns resolution of tcp server's hostname would be scheduled based on dns_resolver's key expiry default, which happens to default to 5s on most systems that use key.dns_resolver for upcall.
As per key.dns_resolver.conf(5):
default_ttl=<number> The number of seconds to set as the expiration on a cached record. This will be overridden if the program manages to re- trieve TTL information along with the addresses (if, for exam- ple, it accesses the DNS directly). The default is 5 seconds. The value must be in the range 1 to INT_MAX.
Make the next async dns resolution no shorter than 120s as we do not want to be upcalling too often.
Cc: stable@vger.kernel.org Fixes: 506c1da44fee ("cifs: use the expiry output of dns_query to schedule next resolution") Signed-off-by: Paulo Alcantara (SUSE) pc@cjr.nz Reviewed-by: Shyam Prasad N sprasad@microsoft.com Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/cifs/cifsglob.h | 3 ++- fs/cifs/connect.c | 2 +- 2 files changed, 3 insertions(+), 2 deletions(-)
--- a/fs/cifs/cifsglob.h +++ b/fs/cifs/cifsglob.h @@ -75,7 +75,8 @@ #define SMB_ECHO_INTERVAL_MAX 600 #define SMB_ECHO_INTERVAL_DEFAULT 60
-/* dns resolution interval in seconds */ +/* dns resolution intervals in seconds */ +#define SMB_DNS_RESOLVE_INTERVAL_MIN 120 #define SMB_DNS_RESOLVE_INTERVAL_DEFAULT 600
/* maximum number of PDUs in one compound */ --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -116,7 +116,7 @@ static int reconn_set_ipaddr_from_hostna * To make sure we don't use the cached entry, retry 1s * after expiry. */ - ttl = (expiry - now + 1); + ttl = max_t(unsigned long, expiry - now, SMB_DNS_RESOLVE_INTERVAL_MIN) + 1; } rc = !rc ? -1 : 0;