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linux-next/fs/lockd/svc4proc.c
Trond Myklebust 5ac5f9d1ce [PATCH] NLM: Fix the NLM_GRANTED callback checks 
If 2 threads attached to the same process are blocking on different locks on
different files (maybe even on different servers) but have the same lock
arguments (i.e.  same offset+length - actually quite common, since most
processes try to lock the entire file) then the first GRANTED call that wakes
one up will also wake the other.

Currently when the NLM_GRANTED callback comes in, lockd walks the list of
blocked locks in search of a match to the lock that the NLM server has
granted.  Although it checks the lock pid, start and end, it fails to check
the filehandle and the server address.

By checking the filehandle and server IP address, we ensure that this only
happens if the locks truly are referencing the same file.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-14 16:09:34 -08:00

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/*
* linux/fs/lockd/svc4proc.c
*
* Lockd server procedures. We don't implement the NLM_*_RES
* procedures because we don't use the async procedures.
*
* Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
*/
#include <linux/types.h>
#include <linux/time.h>
#include <linux/slab.h>
#include <linux/in.h>
#include <linux/sunrpc/svc.h>
#include <linux/sunrpc/clnt.h>
#include <linux/nfsd/nfsd.h>
#include <linux/lockd/lockd.h>
#include <linux/lockd/share.h>
#include <linux/lockd/sm_inter.h>
#define NLMDBG_FACILITY NLMDBG_CLIENT
static u32 nlm4svc_callback(struct svc_rqst *, u32, struct nlm_res *);
static const struct rpc_call_ops nlm4svc_callback_ops;
/*
* Obtain client and file from arguments
*/
static u32
nlm4svc_retrieve_args(struct svc_rqst *rqstp, struct nlm_args *argp,
struct nlm_host **hostp, struct nlm_file **filp)
{
struct nlm_host *host = NULL;
struct nlm_file *file = NULL;
struct nlm_lock *lock = &argp->lock;
u32 error = 0;
/* nfsd callbacks must have been installed for this procedure */
if (!nlmsvc_ops)
return nlm_lck_denied_nolocks;
/* Obtain host handle */
if (!(host = nlmsvc_lookup_host(rqstp))
|| (argp->monitor && !host->h_monitored && nsm_monitor(host) < 0))
goto no_locks;
*hostp = host;
/* Obtain file pointer. Not used by FREE_ALL call. */
if (filp != NULL) {
if ((error = nlm_lookup_file(rqstp, &file, &lock->fh)) != 0)
goto no_locks;
*filp = file;
/* Set up the missing parts of the file_lock structure */
lock->fl.fl_file = file->f_file;
lock->fl.fl_owner = (fl_owner_t) host;
lock->fl.fl_lmops = &nlmsvc_lock_operations;
}
return 0;
no_locks:
if (host)
nlm_release_host(host);
if (error)
return error;
return nlm_lck_denied_nolocks;
}
/*
* NULL: Test for presence of service
*/
static int
nlm4svc_proc_null(struct svc_rqst *rqstp, void *argp, void *resp)
{
dprintk("lockd: NULL called\n");
return rpc_success;
}
/*
* TEST: Check for conflicting lock
*/
static int
nlm4svc_proc_test(struct svc_rqst *rqstp, struct nlm_args *argp,
struct nlm_res *resp)
{
struct nlm_host *host;
struct nlm_file *file;
dprintk("lockd: TEST4 called\n");
resp->cookie = argp->cookie;
/* Don't accept test requests during grace period */
if (nlmsvc_grace_period) {
resp->status = nlm_lck_denied_grace_period;
return rpc_success;
}
/* Obtain client and file */
if ((resp->status = nlm4svc_retrieve_args(rqstp, argp, &host, &file)))
return rpc_success;
/* Now check for conflicting locks */
resp->status = nlmsvc_testlock(file, &argp->lock, &resp->lock);
dprintk("lockd: TEST4 status %d\n", ntohl(resp->status));
nlm_release_host(host);
nlm_release_file(file);
return rpc_success;
}
static int
nlm4svc_proc_lock(struct svc_rqst *rqstp, struct nlm_args *argp,
struct nlm_res *resp)
{
struct nlm_host *host;
struct nlm_file *file;
dprintk("lockd: LOCK called\n");
resp->cookie = argp->cookie;
/* Don't accept new lock requests during grace period */
if (nlmsvc_grace_period && !argp->reclaim) {
resp->status = nlm_lck_denied_grace_period;
return rpc_success;
}
/* Obtain client and file */
if ((resp->status = nlm4svc_retrieve_args(rqstp, argp, &host, &file)))
return rpc_success;
#if 0
/* If supplied state doesn't match current state, we assume it's
* an old request that time-warped somehow. Any error return would
* do in this case because it's irrelevant anyway.
*
* NB: We don't retrieve the remote host's state yet.
*/
if (host->h_nsmstate && host->h_nsmstate != argp->state) {
resp->status = nlm_lck_denied_nolocks;
} else
#endif
/* Now try to lock the file */
resp->status = nlmsvc_lock(rqstp, file, &argp->lock,
argp->block, &argp->cookie);
dprintk("lockd: LOCK status %d\n", ntohl(resp->status));
nlm_release_host(host);
nlm_release_file(file);
return rpc_success;
}
static int
nlm4svc_proc_cancel(struct svc_rqst *rqstp, struct nlm_args *argp,
struct nlm_res *resp)
{
struct nlm_host *host;
struct nlm_file *file;
dprintk("lockd: CANCEL called\n");
resp->cookie = argp->cookie;
/* Don't accept requests during grace period */
if (nlmsvc_grace_period) {
resp->status = nlm_lck_denied_grace_period;
return rpc_success;
}
/* Obtain client and file */
if ((resp->status = nlm4svc_retrieve_args(rqstp, argp, &host, &file)))
return rpc_success;
/* Try to cancel request. */
resp->status = nlmsvc_cancel_blocked(file, &argp->lock);
dprintk("lockd: CANCEL status %d\n", ntohl(resp->status));
nlm_release_host(host);
nlm_release_file(file);
return rpc_success;
}
/*
* UNLOCK: release a lock
*/
static int
nlm4svc_proc_unlock(struct svc_rqst *rqstp, struct nlm_args *argp,
struct nlm_res *resp)
{
struct nlm_host *host;
struct nlm_file *file;
dprintk("lockd: UNLOCK called\n");
resp->cookie = argp->cookie;
/* Don't accept new lock requests during grace period */
if (nlmsvc_grace_period) {
resp->status = nlm_lck_denied_grace_period;
return rpc_success;
}
/* Obtain client and file */
if ((resp->status = nlm4svc_retrieve_args(rqstp, argp, &host, &file)))
return rpc_success;
/* Now try to remove the lock */
resp->status = nlmsvc_unlock(file, &argp->lock);
dprintk("lockd: UNLOCK status %d\n", ntohl(resp->status));
nlm_release_host(host);
nlm_release_file(file);
return rpc_success;
}
/*
* GRANTED: A server calls us to tell that a process' lock request
* was granted
*/
static int
nlm4svc_proc_granted(struct svc_rqst *rqstp, struct nlm_args *argp,
struct nlm_res *resp)
{
resp->cookie = argp->cookie;
dprintk("lockd: GRANTED called\n");
resp->status = nlmclnt_grant(&rqstp->rq_addr, &argp->lock);
dprintk("lockd: GRANTED status %d\n", ntohl(resp->status));
return rpc_success;
}
/*
* `Async' versions of the above service routines. They aren't really,
* because we send the callback before the reply proper. I hope this
* doesn't break any clients.
*/
static int
nlm4svc_proc_test_msg(struct svc_rqst *rqstp, struct nlm_args *argp,
void *resp)
{
struct nlm_res res;
u32 stat;
dprintk("lockd: TEST_MSG called\n");
memset(&res, 0, sizeof(res));
if ((stat = nlm4svc_proc_test(rqstp, argp, &res)) == 0)
stat = nlm4svc_callback(rqstp, NLMPROC_TEST_RES, &res);
return stat;
}
static int
nlm4svc_proc_lock_msg(struct svc_rqst *rqstp, struct nlm_args *argp,
void *resp)
{
struct nlm_res res;
u32 stat;
dprintk("lockd: LOCK_MSG called\n");
memset(&res, 0, sizeof(res));
if ((stat = nlm4svc_proc_lock(rqstp, argp, &res)) == 0)
stat = nlm4svc_callback(rqstp, NLMPROC_LOCK_RES, &res);
return stat;
}
static int
nlm4svc_proc_cancel_msg(struct svc_rqst *rqstp, struct nlm_args *argp,
void *resp)
{
struct nlm_res res;
u32 stat;
dprintk("lockd: CANCEL_MSG called\n");
memset(&res, 0, sizeof(res));
if ((stat = nlm4svc_proc_cancel(rqstp, argp, &res)) == 0)
stat = nlm4svc_callback(rqstp, NLMPROC_CANCEL_RES, &res);
return stat;
}
static int
nlm4svc_proc_unlock_msg(struct svc_rqst *rqstp, struct nlm_args *argp,
void *resp)
{
struct nlm_res res;
u32 stat;
dprintk("lockd: UNLOCK_MSG called\n");
memset(&res, 0, sizeof(res));
if ((stat = nlm4svc_proc_unlock(rqstp, argp, &res)) == 0)
stat = nlm4svc_callback(rqstp, NLMPROC_UNLOCK_RES, &res);
return stat;
}
static int
nlm4svc_proc_granted_msg(struct svc_rqst *rqstp, struct nlm_args *argp,
void *resp)
{
struct nlm_res res;
u32 stat;
dprintk("lockd: GRANTED_MSG called\n");
memset(&res, 0, sizeof(res));
if ((stat = nlm4svc_proc_granted(rqstp, argp, &res)) == 0)
stat = nlm4svc_callback(rqstp, NLMPROC_GRANTED_RES, &res);
return stat;
}
/*
* SHARE: create a DOS share or alter existing share.
*/
static int
nlm4svc_proc_share(struct svc_rqst *rqstp, struct nlm_args *argp,
struct nlm_res *resp)
{
struct nlm_host *host;
struct nlm_file *file;
dprintk("lockd: SHARE called\n");
resp->cookie = argp->cookie;
/* Don't accept new lock requests during grace period */
if (nlmsvc_grace_period && !argp->reclaim) {
resp->status = nlm_lck_denied_grace_period;
return rpc_success;
}
/* Obtain client and file */
if ((resp->status = nlm4svc_retrieve_args(rqstp, argp, &host, &file)))
return rpc_success;
/* Now try to create the share */
resp->status = nlmsvc_share_file(host, file, argp);
dprintk("lockd: SHARE status %d\n", ntohl(resp->status));
nlm_release_host(host);
nlm_release_file(file);
return rpc_success;
}
/*
* UNSHARE: Release a DOS share.
*/
static int
nlm4svc_proc_unshare(struct svc_rqst *rqstp, struct nlm_args *argp,
struct nlm_res *resp)
{
struct nlm_host *host;
struct nlm_file *file;
dprintk("lockd: UNSHARE called\n");
resp->cookie = argp->cookie;
/* Don't accept requests during grace period */
if (nlmsvc_grace_period) {
resp->status = nlm_lck_denied_grace_period;
return rpc_success;
}
/* Obtain client and file */
if ((resp->status = nlm4svc_retrieve_args(rqstp, argp, &host, &file)))
return rpc_success;
/* Now try to lock the file */
resp->status = nlmsvc_unshare_file(host, file, argp);
dprintk("lockd: UNSHARE status %d\n", ntohl(resp->status));
nlm_release_host(host);
nlm_release_file(file);
return rpc_success;
}
/*
* NM_LOCK: Create an unmonitored lock
*/
static int
nlm4svc_proc_nm_lock(struct svc_rqst *rqstp, struct nlm_args *argp,
struct nlm_res *resp)
{
dprintk("lockd: NM_LOCK called\n");
argp->monitor = 0; /* just clean the monitor flag */
return nlm4svc_proc_lock(rqstp, argp, resp);
}
/*
* FREE_ALL: Release all locks and shares held by client
*/
static int
nlm4svc_proc_free_all(struct svc_rqst *rqstp, struct nlm_args *argp,
void *resp)
{
struct nlm_host *host;
/* Obtain client */
if (nlm4svc_retrieve_args(rqstp, argp, &host, NULL))
return rpc_success;
nlmsvc_free_host_resources(host);
nlm_release_host(host);
return rpc_success;
}
/*
* SM_NOTIFY: private callback from statd (not part of official NLM proto)
*/
static int
nlm4svc_proc_sm_notify(struct svc_rqst *rqstp, struct nlm_reboot *argp,
void *resp)
{
struct sockaddr_in saddr = rqstp->rq_addr;
int vers = argp->vers;
int prot = argp->proto >> 1;
struct nlm_host *host;
dprintk("lockd: SM_NOTIFY called\n");
if (saddr.sin_addr.s_addr != htonl(INADDR_LOOPBACK)
|| ntohs(saddr.sin_port) >= 1024) {
printk(KERN_WARNING
"lockd: rejected NSM callback from %08x:%d\n",
ntohl(rqstp->rq_addr.sin_addr.s_addr),
ntohs(rqstp->rq_addr.sin_port));
return rpc_system_err;
}
/* Obtain the host pointer for this NFS server and try to
* reclaim all locks we hold on this server.
*/
saddr.sin_addr.s_addr = argp->addr;
if ((argp->proto & 1)==0) {
if ((host = nlmclnt_lookup_host(&saddr, prot, vers)) != NULL) {
nlmclnt_recovery(host, argp->state);
nlm_release_host(host);
}
} else {
/* If we run on an NFS server, delete all locks held by the client */
if ((host = nlm_lookup_host(1, &saddr, prot, vers)) != NULL) {
nlmsvc_free_host_resources(host);
nlm_release_host(host);
}
}
return rpc_success;
}
/*
* client sent a GRANTED_RES, let's remove the associated block
*/
static int
nlm4svc_proc_granted_res(struct svc_rqst *rqstp, struct nlm_res *argp,
void *resp)
{
if (!nlmsvc_ops)
return rpc_success;
dprintk("lockd: GRANTED_RES called\n");
nlmsvc_grant_reply(rqstp, &argp->cookie, argp->status);
return rpc_success;
}
/*
* This is the generic lockd callback for async RPC calls
*/
static u32
nlm4svc_callback(struct svc_rqst *rqstp, u32 proc, struct nlm_res *resp)
{
struct nlm_host *host;
struct nlm_rqst *call;
if (!(call = nlmclnt_alloc_call()))
return rpc_system_err;
host = nlmclnt_lookup_host(&rqstp->rq_addr,
rqstp->rq_prot, rqstp->rq_vers);
if (!host) {
kfree(call);
return rpc_system_err;
}
call->a_flags = RPC_TASK_ASYNC;
call->a_host = host;
memcpy(&call->a_args, resp, sizeof(*resp));
if (nlmsvc_async_call(call, proc, &nlm4svc_callback_ops) < 0)
goto error;
return rpc_success;
error:
kfree(call);
nlm_release_host(host);
return rpc_system_err;
}
static void nlm4svc_callback_exit(struct rpc_task *task, void *data)
{
struct nlm_rqst *call = data;
if (task->tk_status < 0) {
dprintk("lockd: %4d callback failed (errno = %d)\n",
task->tk_pid, -task->tk_status);
}
nlm_release_host(call->a_host);
kfree(call);
}
static const struct rpc_call_ops nlm4svc_callback_ops = {
.rpc_call_done = nlm4svc_callback_exit,
};
/*
* NLM Server procedures.
*/
#define nlm4svc_encode_norep nlm4svc_encode_void
#define nlm4svc_decode_norep nlm4svc_decode_void
#define nlm4svc_decode_testres nlm4svc_decode_void
#define nlm4svc_decode_lockres nlm4svc_decode_void
#define nlm4svc_decode_unlockres nlm4svc_decode_void
#define nlm4svc_decode_cancelres nlm4svc_decode_void
#define nlm4svc_decode_grantedres nlm4svc_decode_void
#define nlm4svc_proc_none nlm4svc_proc_null
#define nlm4svc_proc_test_res nlm4svc_proc_null
#define nlm4svc_proc_lock_res nlm4svc_proc_null
#define nlm4svc_proc_cancel_res nlm4svc_proc_null
#define nlm4svc_proc_unlock_res nlm4svc_proc_null
struct nlm_void { int dummy; };
#define PROC(name, xargt, xrest, argt, rest, respsize) \
{ .pc_func = (svc_procfunc) nlm4svc_proc_##name, \
.pc_decode = (kxdrproc_t) nlm4svc_decode_##xargt, \
.pc_encode = (kxdrproc_t) nlm4svc_encode_##xrest, \
.pc_release = NULL, \
.pc_argsize = sizeof(struct nlm_##argt), \
.pc_ressize = sizeof(struct nlm_##rest), \
.pc_xdrressize = respsize, \
}
#define Ck (1+XDR_QUADLEN(NLM_MAXCOOKIELEN)) /* cookie */
#define No (1+1024/4) /* netobj */
#define St 1 /* status */
#define Rg 4 /* range (offset + length) */
struct svc_procedure nlmsvc_procedures4[] = {
PROC(null, void, void, void, void, 1),
PROC(test, testargs, testres, args, res, Ck+St+2+No+Rg),
PROC(lock, lockargs, res, args, res, Ck+St),
PROC(cancel, cancargs, res, args, res, Ck+St),
PROC(unlock, unlockargs, res, args, res, Ck+St),
PROC(granted, testargs, res, args, res, Ck+St),
PROC(test_msg, testargs, norep, args, void, 1),
PROC(lock_msg, lockargs, norep, args, void, 1),
PROC(cancel_msg, cancargs, norep, args, void, 1),
PROC(unlock_msg, unlockargs, norep, args, void, 1),
PROC(granted_msg, testargs, norep, args, void, 1),
PROC(test_res, testres, norep, res, void, 1),
PROC(lock_res, lockres, norep, res, void, 1),
PROC(cancel_res, cancelres, norep, res, void, 1),
PROC(unlock_res, unlockres, norep, res, void, 1),
PROC(granted_res, res, norep, res, void, 1),
/* statd callback */
PROC(sm_notify, reboot, void, reboot, void, 1),
PROC(none, void, void, void, void, 0),
PROC(none, void, void, void, void, 0),
PROC(none, void, void, void, void, 0),
PROC(share, shareargs, shareres, args, res, Ck+St+1),
PROC(unshare, shareargs, shareres, args, res, Ck+St+1),
PROC(nm_lock, lockargs, res, args, res, Ck+St),
PROC(free_all, notify, void, args, void, 1),
};
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