linux/fs/nfs/callback.c
Jeff Layton 6ffa30d3f7 nfs: don't call blocking operations while !TASK_RUNNING
Bruce reported seeing this warning pop when mounting using v4.1:

     ------------[ cut here ]------------
     WARNING: CPU: 1 PID: 1121 at kernel/sched/core.c:7300 __might_sleep+0xbd/0xd0()
    do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff810ff58f>] prepare_to_wait+0x2f/0x90
    Modules linked in: rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace sunrpc fscache ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 xt_conntrack ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_security ip6table_raw ip6table_filter ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw snd_hda_codec_generic snd_hda_intel snd_hda_controller snd_hda_codec snd_hwdep snd_pcm snd_timer ppdev joydev snd virtio_console virtio_balloon pcspkr serio_raw parport_pc parport pvpanic floppy soundcore i2c_piix4 virtio_blk virtio_net qxl drm_kms_helper ttm drm virtio_pci virtio_ring ata_generic virtio pata_acpi
    CPU: 1 PID: 1121 Comm: nfsv4.1-svc Not tainted 3.19.0-rc4+ #25
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140709_153950- 04/01/2014
     0000000000000000 000000004e5e3f73 ffff8800b998fb48 ffffffff8186ac78
     0000000000000000 ffff8800b998fba0 ffff8800b998fb88 ffffffff810ac9da
     ffff8800b998fb68 ffffffff81c923e7 00000000000004d9 0000000000000000
    Call Trace:
     [<ffffffff8186ac78>] dump_stack+0x4c/0x65
     [<ffffffff810ac9da>] warn_slowpath_common+0x8a/0xc0
     [<ffffffff810aca65>] warn_slowpath_fmt+0x55/0x70
     [<ffffffff810ff58f>] ? prepare_to_wait+0x2f/0x90
     [<ffffffff810ff58f>] ? prepare_to_wait+0x2f/0x90
     [<ffffffff810dd2ad>] __might_sleep+0xbd/0xd0
     [<ffffffff8124c973>] kmem_cache_alloc_trace+0x243/0x430
     [<ffffffff810d941e>] ? groups_alloc+0x3e/0x130
     [<ffffffff810d941e>] groups_alloc+0x3e/0x130
     [<ffffffffa0301b1e>] svcauth_unix_accept+0x16e/0x290 [sunrpc]
     [<ffffffffa0300571>] svc_authenticate+0xe1/0xf0 [sunrpc]
     [<ffffffffa02fc564>] svc_process_common+0x244/0x6a0 [sunrpc]
     [<ffffffffa02fd044>] bc_svc_process+0x1c4/0x260 [sunrpc]
     [<ffffffffa03d5478>] nfs41_callback_svc+0x128/0x1f0 [nfsv4]
     [<ffffffff810ff970>] ? wait_woken+0xc0/0xc0
     [<ffffffffa03d5350>] ? nfs4_callback_svc+0x60/0x60 [nfsv4]
     [<ffffffff810d45bf>] kthread+0x11f/0x140
     [<ffffffff810ea815>] ? local_clock+0x15/0x30
     [<ffffffff810d44a0>] ? kthread_create_on_node+0x250/0x250
     [<ffffffff81874bfc>] ret_from_fork+0x7c/0xb0
     [<ffffffff810d44a0>] ? kthread_create_on_node+0x250/0x250
    ---[ end trace 675220a11e30f4f2 ]---

nfs41_callback_svc does most of its work while in TASK_INTERRUPTIBLE,
which is just wrong. Fix that by finishing the wait immediately if we've
found that the list has something on it.

Also, we don't expect this kthread to accept signals, so we should be
using a TASK_UNINTERRUPTIBLE sleep instead. That however, opens us up
hung task warnings from the watchdog, so have the schedule_timeout
wake up every 60s if there's no callback activity.

Reported-by: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-01-30 20:39:50 -05:00

500 lines
12 KiB
C

/*
* linux/fs/nfs/callback.c
*
* Copyright (C) 2004 Trond Myklebust
*
* NFSv4 callback handling
*/
#include <linux/completion.h>
#include <linux/ip.h>
#include <linux/module.h>
#include <linux/sunrpc/svc.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/nfs_fs.h>
#include <linux/errno.h>
#include <linux/mutex.h>
#include <linux/freezer.h>
#include <linux/kthread.h>
#include <linux/sunrpc/svcauth_gss.h>
#include <linux/sunrpc/bc_xprt.h>
#include <net/inet_sock.h>
#include "nfs4_fs.h"
#include "callback.h"
#include "internal.h"
#include "netns.h"
#define NFSDBG_FACILITY NFSDBG_CALLBACK
struct nfs_callback_data {
unsigned int users;
struct svc_serv *serv;
struct svc_rqst *rqst;
struct task_struct *task;
};
static struct nfs_callback_data nfs_callback_info[NFS4_MAX_MINOR_VERSION + 1];
static DEFINE_MUTEX(nfs_callback_mutex);
static struct svc_program nfs4_callback_program;
static int nfs4_callback_up_net(struct svc_serv *serv, struct net *net)
{
int ret;
struct nfs_net *nn = net_generic(net, nfs_net_id);
ret = svc_create_xprt(serv, "tcp", net, PF_INET,
nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
if (ret <= 0)
goto out_err;
nn->nfs_callback_tcpport = ret;
dprintk("NFS: Callback listener port = %u (af %u, net %p)\n",
nn->nfs_callback_tcpport, PF_INET, net);
ret = svc_create_xprt(serv, "tcp", net, PF_INET6,
nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
if (ret > 0) {
nn->nfs_callback_tcpport6 = ret;
dprintk("NFS: Callback listener port = %u (af %u, net %p)\n",
nn->nfs_callback_tcpport6, PF_INET6, net);
} else if (ret != -EAFNOSUPPORT)
goto out_err;
return 0;
out_err:
return (ret) ? ret : -ENOMEM;
}
/*
* This is the NFSv4 callback kernel thread.
*/
static int
nfs4_callback_svc(void *vrqstp)
{
int err;
struct svc_rqst *rqstp = vrqstp;
set_freezable();
while (!kthread_should_stop()) {
/*
* Listen for a request on the socket
*/
err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT);
if (err == -EAGAIN || err == -EINTR)
continue;
svc_process(rqstp);
}
return 0;
}
/*
* Prepare to bring up the NFSv4 callback service
*/
static struct svc_rqst *
nfs4_callback_up(struct svc_serv *serv)
{
return svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
}
#if defined(CONFIG_NFS_V4_1)
static int nfs41_callback_up_net(struct svc_serv *serv, struct net *net)
{
/*
* Create an svc_sock for the back channel service that shares the
* fore channel connection.
* Returns the input port (0) and sets the svc_serv bc_xprt on success
*/
return svc_create_xprt(serv, "tcp-bc", net, PF_INET, 0,
SVC_SOCK_ANONYMOUS);
}
/*
* The callback service for NFSv4.1 callbacks
*/
static int
nfs41_callback_svc(void *vrqstp)
{
struct svc_rqst *rqstp = vrqstp;
struct svc_serv *serv = rqstp->rq_server;
struct rpc_rqst *req;
int error;
DEFINE_WAIT(wq);
set_freezable();
while (!kthread_should_stop()) {
if (try_to_freeze())
continue;
prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_UNINTERRUPTIBLE);
spin_lock_bh(&serv->sv_cb_lock);
if (!list_empty(&serv->sv_cb_list)) {
req = list_first_entry(&serv->sv_cb_list,
struct rpc_rqst, rq_bc_list);
list_del(&req->rq_bc_list);
spin_unlock_bh(&serv->sv_cb_lock);
finish_wait(&serv->sv_cb_waitq, &wq);
dprintk("Invoking bc_svc_process()\n");
error = bc_svc_process(serv, req, rqstp);
dprintk("bc_svc_process() returned w/ error code= %d\n",
error);
} else {
spin_unlock_bh(&serv->sv_cb_lock);
/* schedule_timeout to game the hung task watchdog */
schedule_timeout(60 * HZ);
finish_wait(&serv->sv_cb_waitq, &wq);
}
}
return 0;
}
/*
* Bring up the NFSv4.1 callback service
*/
static struct svc_rqst *
nfs41_callback_up(struct svc_serv *serv)
{
struct svc_rqst *rqstp;
INIT_LIST_HEAD(&serv->sv_cb_list);
spin_lock_init(&serv->sv_cb_lock);
init_waitqueue_head(&serv->sv_cb_waitq);
rqstp = svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
if (IS_ERR(rqstp)) {
svc_xprt_put(serv->sv_bc_xprt);
serv->sv_bc_xprt = NULL;
}
dprintk("--> %s return %d\n", __func__, PTR_ERR_OR_ZERO(rqstp));
return rqstp;
}
static void nfs_minorversion_callback_svc_setup(struct svc_serv *serv,
struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
{
*rqstpp = nfs41_callback_up(serv);
*callback_svc = nfs41_callback_svc;
}
static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
struct svc_serv *serv)
{
if (minorversion)
/*
* Save the svc_serv in the transport so that it can
* be referenced when the session backchannel is initialized
*/
xprt->bc_serv = serv;
}
#else
static int nfs41_callback_up_net(struct svc_serv *serv, struct net *net)
{
return 0;
}
static void nfs_minorversion_callback_svc_setup(struct svc_serv *serv,
struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
{
*rqstpp = ERR_PTR(-ENOTSUPP);
*callback_svc = ERR_PTR(-ENOTSUPP);
}
static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
struct svc_serv *serv)
{
}
#endif /* CONFIG_NFS_V4_1 */
static int nfs_callback_start_svc(int minorversion, struct rpc_xprt *xprt,
struct svc_serv *serv)
{
struct svc_rqst *rqstp;
int (*callback_svc)(void *vrqstp);
struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
int ret;
nfs_callback_bc_serv(minorversion, xprt, serv);
if (cb_info->task)
return 0;
switch (minorversion) {
case 0:
/* v4.0 callback setup */
rqstp = nfs4_callback_up(serv);
callback_svc = nfs4_callback_svc;
break;
default:
nfs_minorversion_callback_svc_setup(serv,
&rqstp, &callback_svc);
}
if (IS_ERR(rqstp))
return PTR_ERR(rqstp);
svc_sock_update_bufs(serv);
cb_info->serv = serv;
cb_info->rqst = rqstp;
cb_info->task = kthread_create(callback_svc, cb_info->rqst,
"nfsv4.%u-svc", minorversion);
if (IS_ERR(cb_info->task)) {
ret = PTR_ERR(cb_info->task);
svc_exit_thread(cb_info->rqst);
cb_info->rqst = NULL;
cb_info->task = NULL;
return ret;
}
rqstp->rq_task = cb_info->task;
wake_up_process(cb_info->task);
dprintk("nfs_callback_up: service started\n");
return 0;
}
static void nfs_callback_down_net(u32 minorversion, struct svc_serv *serv, struct net *net)
{
struct nfs_net *nn = net_generic(net, nfs_net_id);
if (--nn->cb_users[minorversion])
return;
dprintk("NFS: destroy per-net callback data; net=%p\n", net);
svc_shutdown_net(serv, net);
}
static int nfs_callback_up_net(int minorversion, struct svc_serv *serv, struct net *net)
{
struct nfs_net *nn = net_generic(net, nfs_net_id);
int ret;
if (nn->cb_users[minorversion]++)
return 0;
dprintk("NFS: create per-net callback data; net=%p\n", net);
ret = svc_bind(serv, net);
if (ret < 0) {
printk(KERN_WARNING "NFS: bind callback service failed\n");
goto err_bind;
}
switch (minorversion) {
case 0:
ret = nfs4_callback_up_net(serv, net);
break;
case 1:
case 2:
ret = nfs41_callback_up_net(serv, net);
break;
default:
printk(KERN_ERR "NFS: unknown callback version: %d\n",
minorversion);
ret = -EINVAL;
break;
}
if (ret < 0) {
printk(KERN_ERR "NFS: callback service start failed\n");
goto err_socks;
}
return 0;
err_socks:
svc_rpcb_cleanup(serv, net);
err_bind:
dprintk("NFS: Couldn't create callback socket: err = %d; "
"net = %p\n", ret, net);
return ret;
}
static struct svc_serv *nfs_callback_create_svc(int minorversion)
{
struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
struct svc_serv *serv;
/*
* Check whether we're already up and running.
*/
if (cb_info->task) {
/*
* Note: increase service usage, because later in case of error
* svc_destroy() will be called.
*/
svc_get(cb_info->serv);
return cb_info->serv;
}
/*
* Sanity check: if there's no task,
* we should be the first user ...
*/
if (cb_info->users)
printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n",
cb_info->users);
serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
if (!serv) {
printk(KERN_ERR "nfs_callback_create_svc: create service failed\n");
return ERR_PTR(-ENOMEM);
}
/* As there is only one thread we need to over-ride the
* default maximum of 80 connections
*/
serv->sv_maxconn = 1024;
dprintk("nfs_callback_create_svc: service created\n");
return serv;
}
/*
* Bring up the callback thread if it is not already up.
*/
int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
{
struct svc_serv *serv;
struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
int ret;
struct net *net = xprt->xprt_net;
mutex_lock(&nfs_callback_mutex);
serv = nfs_callback_create_svc(minorversion);
if (IS_ERR(serv)) {
ret = PTR_ERR(serv);
goto err_create;
}
ret = nfs_callback_up_net(minorversion, serv, net);
if (ret < 0)
goto err_net;
ret = nfs_callback_start_svc(minorversion, xprt, serv);
if (ret < 0)
goto err_start;
cb_info->users++;
/*
* svc_create creates the svc_serv with sv_nrthreads == 1, and then
* svc_prepare_thread increments that. So we need to call svc_destroy
* on both success and failure so that the refcount is 1 when the
* thread exits.
*/
err_net:
svc_destroy(serv);
err_create:
mutex_unlock(&nfs_callback_mutex);
return ret;
err_start:
nfs_callback_down_net(minorversion, serv, net);
dprintk("NFS: Couldn't create server thread; err = %d\n", ret);
goto err_net;
}
/*
* Kill the callback thread if it's no longer being used.
*/
void nfs_callback_down(int minorversion, struct net *net)
{
struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
mutex_lock(&nfs_callback_mutex);
nfs_callback_down_net(minorversion, cb_info->serv, net);
cb_info->users--;
if (cb_info->users == 0 && cb_info->task != NULL) {
kthread_stop(cb_info->task);
dprintk("nfs_callback_down: service stopped\n");
svc_exit_thread(cb_info->rqst);
dprintk("nfs_callback_down: service destroyed\n");
cb_info->serv = NULL;
cb_info->rqst = NULL;
cb_info->task = NULL;
}
mutex_unlock(&nfs_callback_mutex);
}
/* Boolean check of RPC_AUTH_GSS principal */
int
check_gss_callback_principal(struct nfs_client *clp, struct svc_rqst *rqstp)
{
char *p = rqstp->rq_cred.cr_principal;
if (rqstp->rq_authop->flavour != RPC_AUTH_GSS)
return 1;
/* No RPC_AUTH_GSS on NFSv4.1 back channel yet */
if (clp->cl_minorversion != 0)
return 0;
/*
* It might just be a normal user principal, in which case
* userspace won't bother to tell us the name at all.
*/
if (p == NULL)
return 0;
/*
* Did we get the acceptor from userland during the SETCLIENID
* negotiation?
*/
if (clp->cl_acceptor)
return !strcmp(p, clp->cl_acceptor);
/*
* Otherwise try to verify it using the cl_hostname. Note that this
* doesn't work if a non-canonical hostname was used in the devname.
*/
/* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
if (memcmp(p, "nfs@", 4) != 0)
return 0;
p += 4;
if (strcmp(p, clp->cl_hostname) != 0)
return 0;
return 1;
}
/*
* pg_authenticate method for nfsv4 callback threads.
*
* The authflavor has been negotiated, so an incorrect flavor is a server
* bug. Drop packets with incorrect authflavor.
*
* All other checking done after NFS decoding where the nfs_client can be
* found in nfs4_callback_compound
*/
static int nfs_callback_authenticate(struct svc_rqst *rqstp)
{
switch (rqstp->rq_authop->flavour) {
case RPC_AUTH_NULL:
if (rqstp->rq_proc != CB_NULL)
return SVC_DROP;
break;
case RPC_AUTH_GSS:
/* No RPC_AUTH_GSS support yet in NFSv4.1 */
if (svc_is_backchannel(rqstp))
return SVC_DROP;
}
return SVC_OK;
}
/*
* Define NFS4 callback program
*/
static struct svc_version *nfs4_callback_version[] = {
[1] = &nfs4_callback_version1,
[4] = &nfs4_callback_version4,
};
static struct svc_stat nfs4_callback_stats;
static struct svc_program nfs4_callback_program = {
.pg_prog = NFS4_CALLBACK, /* RPC service number */
.pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */
.pg_vers = nfs4_callback_version, /* version table */
.pg_name = "NFSv4 callback", /* service name */
.pg_class = "nfs", /* authentication class */
.pg_stats = &nfs4_callback_stats,
.pg_authenticate = nfs_callback_authenticate,
};