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[PATCH] NFS: use a constant value for TCP retransmit timeouts
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 Implement a best practice: don't use exponential backoff when computing
 retransmit timeout values on TCP connections, but simply retransmit
 at regular intervals.

 This also fixes a bug introduced when xprt_reset_majortimeo() was added.

 Test-plan:
 Enable RPC debugging and watch timeout behavior on a NFS/TCP mount.

 Version: Thu, 11 Aug 2005 16:02:19 -0400

 Signed-off-by: Chuck Lever <cel@netapp.com>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
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Chuck Lever authored and Trond Myklebust committed Sep 23, 2005
1 parent da35187 commit eab5c08
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Showing 2 changed files with 37 additions and 40 deletions.
73 changes: 35 additions & 38 deletions fs/nfs/inode.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -358,6 +358,35 @@ nfs_sb_init(struct super_block *sb, rpc_authflavor_t authflavor)
return no_root_error;
}

static void nfs_init_timeout_values(struct rpc_timeout *to, int proto, unsigned int timeo, unsigned int retrans)
{
to->to_initval = timeo * HZ / 10;
to->to_retries = retrans;
if (!to->to_retries)
to->to_retries = 2;

switch (proto) {
case IPPROTO_TCP:
if (!to->to_initval)
to->to_initval = 60 * HZ;
if (to->to_initval > RPC_MAX_TCP_TIMEOUT)
to->to_initval = RPC_MAX_TCP_TIMEOUT;
to->to_increment = to->to_initval;
to->to_maxval = to->to_initval + (to->to_increment * to->to_retries);
to->to_exponential = 0;
break;
case IPPROTO_UDP:
default:
if (!to->to_initval)
to->to_initval = 11 * HZ / 10;
if (to->to_initval > RPC_MAX_UDP_TIMEOUT)
to->to_initval = RPC_MAX_UDP_TIMEOUT;
to->to_maxval = RPC_MAX_UDP_TIMEOUT;
to->to_exponential = 1;
break;
}
}

/*
* Create an RPC client handle.
*/
Expand All @@ -367,22 +396,12 @@ nfs_create_client(struct nfs_server *server, const struct nfs_mount_data *data)
struct rpc_timeout timeparms;
struct rpc_xprt *xprt = NULL;
struct rpc_clnt *clnt = NULL;
int tcp = (data->flags & NFS_MOUNT_TCP);

/* Initialize timeout values */
timeparms.to_initval = data->timeo * HZ / 10;
timeparms.to_retries = data->retrans;
timeparms.to_maxval = tcp ? RPC_MAX_TCP_TIMEOUT : RPC_MAX_UDP_TIMEOUT;
timeparms.to_exponential = 1;
int proto = (data->flags & NFS_MOUNT_TCP) ? IPPROTO_TCP : IPPROTO_UDP;

if (!timeparms.to_initval)
timeparms.to_initval = (tcp ? 600 : 11) * HZ / 10;
if (!timeparms.to_retries)
timeparms.to_retries = 5;
nfs_init_timeout_values(&timeparms, proto, data->timeo, data->retrans);

/* create transport and client */
xprt = xprt_create_proto(tcp ? IPPROTO_TCP : IPPROTO_UDP,
&server->addr, &timeparms);
xprt = xprt_create_proto(proto, &server->addr, &timeparms);
if (IS_ERR(xprt)) {
dprintk("%s: cannot create RPC transport. Error = %ld\n",
__FUNCTION__, PTR_ERR(xprt));
Expand Down Expand Up @@ -1674,7 +1693,7 @@ static int nfs4_fill_super(struct super_block *sb, struct nfs4_mount_data *data,
struct rpc_clnt *clnt = NULL;
struct rpc_timeout timeparms;
rpc_authflavor_t authflavour;
int proto, err = -EIO;
int err = -EIO;

sb->s_blocksize_bits = 0;
sb->s_blocksize = 0;
Expand All @@ -1692,30 +1711,8 @@ static int nfs4_fill_super(struct super_block *sb, struct nfs4_mount_data *data,
server->acdirmax = data->acdirmax*HZ;

server->rpc_ops = &nfs_v4_clientops;
/* Initialize timeout values */

timeparms.to_initval = data->timeo * HZ / 10;
timeparms.to_retries = data->retrans;
timeparms.to_exponential = 1;
if (!timeparms.to_retries)
timeparms.to_retries = 5;

proto = data->proto;
/* Which IP protocol do we use? */
switch (proto) {
case IPPROTO_TCP:
timeparms.to_maxval = RPC_MAX_TCP_TIMEOUT;
if (!timeparms.to_initval)
timeparms.to_initval = 600 * HZ / 10;
break;
case IPPROTO_UDP:
timeparms.to_maxval = RPC_MAX_UDP_TIMEOUT;
if (!timeparms.to_initval)
timeparms.to_initval = 11 * HZ / 10;
break;
default:
return -EINVAL;
}
nfs_init_timeout_values(&timeparms, data->proto, data->timeo, data->retrans);

clp = nfs4_get_client(&server->addr.sin_addr);
if (!clp) {
Expand All @@ -1740,7 +1737,7 @@ static int nfs4_fill_super(struct super_block *sb, struct nfs4_mount_data *data,

down_write(&clp->cl_sem);
if (IS_ERR(clp->cl_rpcclient)) {
xprt = xprt_create_proto(proto, &server->addr, &timeparms);
xprt = xprt_create_proto(data->proto, &server->addr, &timeparms);
if (IS_ERR(xprt)) {
up_write(&clp->cl_sem);
err = PTR_ERR(xprt);
Expand Down
4 changes: 2 additions & 2 deletions net/sunrpc/xprt.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1453,7 +1453,7 @@ xprt_default_timeout(struct rpc_timeout *to, int proto)
if (proto == IPPROTO_UDP)
xprt_set_timeout(to, 5, 5 * HZ);
else
xprt_set_timeout(to, 5, 60 * HZ);
xprt_set_timeout(to, 2, 60 * HZ);
}

/*
Expand All @@ -1464,7 +1464,7 @@ xprt_set_timeout(struct rpc_timeout *to, unsigned int retr, unsigned long incr)
{
to->to_initval =
to->to_increment = incr;
to->to_maxval = incr * retr;
to->to_maxval = to->to_initval + (incr * retr);
to->to_retries = retr;
to->to_exponential = 0;
}
Expand Down

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