From 7de62bc09fe6d100ebd6c931c3f9a6fa7e6ed10f Mon Sep 17 00:00:00 2001 From: Olga Kornievskaia Date: Wed, 15 Jul 2020 13:17:52 -0400 Subject: SUNRPC dont update timeout value on connection reset Current behaviour: every time a v3 operation is re-sent to the server we update (double) the timeout. There is no distinction between whether or not the previous timer had expired before the re-sent happened. Here's the scenario: 1. Client sends a v3 operation 2. Server RST-s the connection (prior to the timeout) (eg., connection is immediately reset) 3. Client re-sends a v3 operation but the timeout is now 120sec. As a result, an application sees 2mins pause before a retry in case server again does not reply. Instead, this patch proposes to keep track off when the minor timeout should happen and if it didn't, then don't update the new timeout. Value is updated based on the previous value to make timeouts predictable. Signed-off-by: Olga Kornievskaia Signed-off-by: Trond Myklebust --- include/linux/sunrpc/xprt.h | 1 + net/sunrpc/xprt.c | 9 +++++++++ 2 files changed, 10 insertions(+) diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h index e64bd8222f55..a603d48d2b2c 100644 --- a/include/linux/sunrpc/xprt.h +++ b/include/linux/sunrpc/xprt.h @@ -101,6 +101,7 @@ struct rpc_rqst { * used in the softirq. */ unsigned long rq_majortimeo; /* major timeout alarm */ + unsigned long rq_minortimeo; /* minor timeout alarm */ unsigned long rq_timeout; /* Current timeout value */ ktime_t rq_rtt; /* round-trip time */ unsigned int rq_retries; /* # of retries */ diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index d5cc5db9dbf3..6ba9d5842629 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -607,6 +607,11 @@ static void xprt_reset_majortimeo(struct rpc_rqst *req) req->rq_majortimeo += xprt_calc_majortimeo(req); } +static void xprt_reset_minortimeo(struct rpc_rqst *req) +{ + req->rq_minortimeo += req->rq_timeout; +} + static void xprt_init_majortimeo(struct rpc_task *task, struct rpc_rqst *req) { unsigned long time_init; @@ -618,6 +623,7 @@ static void xprt_init_majortimeo(struct rpc_task *task, struct rpc_rqst *req) time_init = xprt_abs_ktime_to_jiffies(task->tk_start); req->rq_timeout = task->tk_client->cl_timeout->to_initval; req->rq_majortimeo = time_init + xprt_calc_majortimeo(req); + req->rq_minortimeo = time_init + req->rq_timeout; } /** @@ -631,6 +637,8 @@ int xprt_adjust_timeout(struct rpc_rqst *req) const struct rpc_timeout *to = req->rq_task->tk_client->cl_timeout; int status = 0; + if (time_before(jiffies, req->rq_minortimeo)) + return status; if (time_before(jiffies, req->rq_majortimeo)) { if (to->to_exponential) req->rq_timeout <<= 1; @@ -649,6 +657,7 @@ int xprt_adjust_timeout(struct rpc_rqst *req) spin_unlock(&xprt->transport_lock); status = -ETIMEDOUT; } + xprt_reset_minortimeo(req); if (req->rq_timeout == 0) { printk(KERN_WARNING "xprt_adjust_timeout: rq_timeout = 0!\n"); -- cgit v1.2.3