Revision 35991652baa12ff3d0e420c0d0cb2ad9f7076e5b authored by Mikulas Patocka on 02 June 2012, 23:29:58 UTC, committed by Alasdair G Kergon on 02 June 2012, 23:29:58 UTC
After the failure of a group of paths, any alternative paths that need initialising do not become available until further I/O is sent to the device. Until this has happened, ioctls return -EAGAIN. With this patch, new paths are made available in response to an ioctl too. The processing of the ioctl gets delayed until this has happened. Instead of returning an error, we submit a work item to kmultipathd (that will potentially activate the new path) and retry in ten milliseconds. Note that the patch doesn't retry an ioctl if the ioctl itself fails due to a path failure. Such retries should be handled intelligently by the code that generated the ioctl in the first place, noting that some SCSI commands should not be retried because they are not idempotent (XOR write commands). For commands that could be retried, there is a danger that if the device rejected the SCSI command, the path could be errorneously marked as failed, and the request would be retried on another path which might fail too. It can be determined if the failure happens on the device or on the SCSI controller, but there is no guarantee that all SCSI drivers set these flags correctly. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
1 parent f220fd4
stats.c
/*
* linux/net/sunrpc/stats.c
*
* procfs-based user access to generic RPC statistics. The stats files
* reside in /proc/net/rpc.
*
* The read routines assume that the buffer passed in is just big enough.
* If you implement an RPC service that has its own stats routine which
* appends the generic RPC stats, make sure you don't exceed the PAGE_SIZE
* limit.
*
* Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/sunrpc/metrics.h>
#include <linux/rcupdate.h>
#include "netns.h"
#define RPCDBG_FACILITY RPCDBG_MISC
/*
* Get RPC client stats
*/
static int rpc_proc_show(struct seq_file *seq, void *v) {
const struct rpc_stat *statp = seq->private;
const struct rpc_program *prog = statp->program;
unsigned int i, j;
seq_printf(seq,
"net %u %u %u %u\n",
statp->netcnt,
statp->netudpcnt,
statp->nettcpcnt,
statp->nettcpconn);
seq_printf(seq,
"rpc %u %u %u\n",
statp->rpccnt,
statp->rpcretrans,
statp->rpcauthrefresh);
for (i = 0; i < prog->nrvers; i++) {
const struct rpc_version *vers = prog->version[i];
if (!vers)
continue;
seq_printf(seq, "proc%u %u",
vers->number, vers->nrprocs);
for (j = 0; j < vers->nrprocs; j++)
seq_printf(seq, " %u",
vers->procs[j].p_count);
seq_putc(seq, '\n');
}
return 0;
}
static int rpc_proc_open(struct inode *inode, struct file *file)
{
return single_open(file, rpc_proc_show, PDE(inode)->data);
}
static const struct file_operations rpc_proc_fops = {
.owner = THIS_MODULE,
.open = rpc_proc_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
/*
* Get RPC server stats
*/
void svc_seq_show(struct seq_file *seq, const struct svc_stat *statp) {
const struct svc_program *prog = statp->program;
const struct svc_procedure *proc;
const struct svc_version *vers;
unsigned int i, j;
seq_printf(seq,
"net %u %u %u %u\n",
statp->netcnt,
statp->netudpcnt,
statp->nettcpcnt,
statp->nettcpconn);
seq_printf(seq,
"rpc %u %u %u %u %u\n",
statp->rpccnt,
statp->rpcbadfmt+statp->rpcbadauth+statp->rpcbadclnt,
statp->rpcbadfmt,
statp->rpcbadauth,
statp->rpcbadclnt);
for (i = 0; i < prog->pg_nvers; i++) {
if (!(vers = prog->pg_vers[i]) || !(proc = vers->vs_proc))
continue;
seq_printf(seq, "proc%d %u", i, vers->vs_nproc);
for (j = 0; j < vers->vs_nproc; j++, proc++)
seq_printf(seq, " %u", proc->pc_count);
seq_putc(seq, '\n');
}
}
EXPORT_SYMBOL_GPL(svc_seq_show);
/**
* rpc_alloc_iostats - allocate an rpc_iostats structure
* @clnt: RPC program, version, and xprt
*
*/
struct rpc_iostats *rpc_alloc_iostats(struct rpc_clnt *clnt)
{
return kcalloc(clnt->cl_maxproc, sizeof(struct rpc_iostats), GFP_KERNEL);
}
EXPORT_SYMBOL_GPL(rpc_alloc_iostats);
/**
* rpc_free_iostats - release an rpc_iostats structure
* @stats: doomed rpc_iostats structure
*
*/
void rpc_free_iostats(struct rpc_iostats *stats)
{
kfree(stats);
}
EXPORT_SYMBOL_GPL(rpc_free_iostats);
/**
* rpc_count_iostats - tally up per-task stats
* @task: completed rpc_task
* @stats: array of stat structures
*
* Relies on the caller for serialization.
*/
void rpc_count_iostats(const struct rpc_task *task, struct rpc_iostats *stats)
{
struct rpc_rqst *req = task->tk_rqstp;
struct rpc_iostats *op_metrics;
ktime_t delta;
if (!stats || !req)
return;
op_metrics = &stats[task->tk_msg.rpc_proc->p_statidx];
op_metrics->om_ops++;
op_metrics->om_ntrans += req->rq_ntrans;
op_metrics->om_timeouts += task->tk_timeouts;
op_metrics->om_bytes_sent += req->rq_xmit_bytes_sent;
op_metrics->om_bytes_recv += req->rq_reply_bytes_recvd;
delta = ktime_sub(req->rq_xtime, task->tk_start);
op_metrics->om_queue = ktime_add(op_metrics->om_queue, delta);
op_metrics->om_rtt = ktime_add(op_metrics->om_rtt, req->rq_rtt);
delta = ktime_sub(ktime_get(), task->tk_start);
op_metrics->om_execute = ktime_add(op_metrics->om_execute, delta);
}
EXPORT_SYMBOL_GPL(rpc_count_iostats);
static void _print_name(struct seq_file *seq, unsigned int op,
struct rpc_procinfo *procs)
{
if (procs[op].p_name)
seq_printf(seq, "\t%12s: ", procs[op].p_name);
else if (op == 0)
seq_printf(seq, "\t NULL: ");
else
seq_printf(seq, "\t%12u: ", op);
}
void rpc_print_iostats(struct seq_file *seq, struct rpc_clnt *clnt)
{
struct rpc_iostats *stats = clnt->cl_metrics;
struct rpc_xprt *xprt;
unsigned int op, maxproc = clnt->cl_maxproc;
if (!stats)
return;
seq_printf(seq, "\tRPC iostats version: %s ", RPC_IOSTATS_VERS);
seq_printf(seq, "p/v: %u/%u (%s)\n",
clnt->cl_prog, clnt->cl_vers, clnt->cl_protname);
rcu_read_lock();
xprt = rcu_dereference(clnt->cl_xprt);
if (xprt)
xprt->ops->print_stats(xprt, seq);
rcu_read_unlock();
seq_printf(seq, "\tper-op statistics\n");
for (op = 0; op < maxproc; op++) {
struct rpc_iostats *metrics = &stats[op];
_print_name(seq, op, clnt->cl_procinfo);
seq_printf(seq, "%lu %lu %lu %Lu %Lu %Lu %Lu %Lu\n",
metrics->om_ops,
metrics->om_ntrans,
metrics->om_timeouts,
metrics->om_bytes_sent,
metrics->om_bytes_recv,
ktime_to_ms(metrics->om_queue),
ktime_to_ms(metrics->om_rtt),
ktime_to_ms(metrics->om_execute));
}
}
EXPORT_SYMBOL_GPL(rpc_print_iostats);
/*
* Register/unregister RPC proc files
*/
static inline struct proc_dir_entry *
do_register(struct net *net, const char *name, void *data,
const struct file_operations *fops)
{
struct sunrpc_net *sn;
dprintk("RPC: registering /proc/net/rpc/%s\n", name);
sn = net_generic(net, sunrpc_net_id);
return proc_create_data(name, 0, sn->proc_net_rpc, fops, data);
}
struct proc_dir_entry *
rpc_proc_register(struct net *net, struct rpc_stat *statp)
{
return do_register(net, statp->program->name, statp, &rpc_proc_fops);
}
EXPORT_SYMBOL_GPL(rpc_proc_register);
void
rpc_proc_unregister(struct net *net, const char *name)
{
struct sunrpc_net *sn;
sn = net_generic(net, sunrpc_net_id);
remove_proc_entry(name, sn->proc_net_rpc);
}
EXPORT_SYMBOL_GPL(rpc_proc_unregister);
struct proc_dir_entry *
svc_proc_register(struct net *net, struct svc_stat *statp, const struct file_operations *fops)
{
return do_register(net, statp->program->pg_name, statp, fops);
}
EXPORT_SYMBOL_GPL(svc_proc_register);
void
svc_proc_unregister(struct net *net, const char *name)
{
struct sunrpc_net *sn;
sn = net_generic(net, sunrpc_net_id);
remove_proc_entry(name, sn->proc_net_rpc);
}
EXPORT_SYMBOL_GPL(svc_proc_unregister);
int rpc_proc_init(struct net *net)
{
struct sunrpc_net *sn;
dprintk("RPC: registering /proc/net/rpc\n");
sn = net_generic(net, sunrpc_net_id);
sn->proc_net_rpc = proc_mkdir("rpc", net->proc_net);
if (sn->proc_net_rpc == NULL)
return -ENOMEM;
return 0;
}
void rpc_proc_exit(struct net *net)
{
dprintk("RPC: unregistering /proc/net/rpc\n");
remove_proc_entry("rpc", net->proc_net);
}
![swh spinner](/static/img/swh-spinner.gif)
Computing file changes ...