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kernel-fxtec-pro1x/fs/nfsd/nfs4callback.c
Olga Kornievskaia ff7d9756b5 nfsd: use static memory for callback program and stats 
There's no need to dynamically allocate this memory, and doing so may
create the possibility of races on shutdown of the rpc client.  (We've
witnessed it only after adding rpcsec_gss support to the server, after
which the rpc code can send destroys calls that expect to still be able
to access the rpc_stats structure after it has been destroyed.)

Such races are in theory possible if the module containing this "static"
memory is removed very quickly after an rpc client is destroyed, but
we haven't seen that happen.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-04-23 16:13:42 -04:00

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/*
* linux/fs/nfsd/nfs4callback.c
*
* Copyright (c) 2001 The Regents of the University of Michigan.
* All rights reserved.
*
* Kendrick Smith <kmsmith@umich.edu>
* Andy Adamson <andros@umich.edu>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <linux/module.h>
#include <linux/list.h>
#include <linux/inet.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/kthread.h>
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/svc.h>
#include <linux/sunrpc/clnt.h>
#include <linux/nfsd/nfsd.h>
#include <linux/nfsd/state.h>
#include <linux/sunrpc/sched.h>
#include <linux/nfs4.h>
#define NFSDDBG_FACILITY NFSDDBG_PROC
#define NFSPROC4_CB_NULL 0
#define NFSPROC4_CB_COMPOUND 1
/* declarations */
static const struct rpc_call_ops nfs4_cb_null_ops;
/* Index of predefined Linux callback client operations */
enum {
NFSPROC4_CLNT_CB_NULL = 0,
NFSPROC4_CLNT_CB_RECALL,
};
enum nfs_cb_opnum4 {
OP_CB_RECALL = 4,
};
#define NFS4_MAXTAGLEN 20
#define NFS4_enc_cb_null_sz 0
#define NFS4_dec_cb_null_sz 0
#define cb_compound_enc_hdr_sz 4
#define cb_compound_dec_hdr_sz (3 + (NFS4_MAXTAGLEN >> 2))
#define op_enc_sz 1
#define op_dec_sz 2
#define enc_nfs4_fh_sz (1 + (NFS4_FHSIZE >> 2))
#define enc_stateid_sz (NFS4_STATEID_SIZE >> 2)
#define NFS4_enc_cb_recall_sz (cb_compound_enc_hdr_sz + \
1 + enc_stateid_sz + \
enc_nfs4_fh_sz)
#define NFS4_dec_cb_recall_sz (cb_compound_dec_hdr_sz + \
op_dec_sz)
/*
* Generic encode routines from fs/nfs/nfs4xdr.c
*/
static inline __be32 *
xdr_writemem(__be32 *p, const void *ptr, int nbytes)
{
int tmp = XDR_QUADLEN(nbytes);
if (!tmp)
return p;
p[tmp-1] = 0;
memcpy(p, ptr, nbytes);
return p + tmp;
}
#define WRITE32(n) *p++ = htonl(n)
#define WRITEMEM(ptr,nbytes) do { \
p = xdr_writemem(p, ptr, nbytes); \
} while (0)
#define RESERVE_SPACE(nbytes) do { \
p = xdr_reserve_space(xdr, nbytes); \
if (!p) dprintk("NFSD: RESERVE_SPACE(%d) failed in function %s\n", (int) (nbytes), __FUNCTION__); \
BUG_ON(!p); \
} while (0)
/*
* Generic decode routines from fs/nfs/nfs4xdr.c
*/
#define DECODE_TAIL \
status = 0; \
out: \
return status; \
xdr_error: \
dprintk("NFSD: xdr error! (%s:%d)\n", __FILE__, __LINE__); \
status = -EIO; \
goto out
#define READ32(x) (x) = ntohl(*p++)
#define READ64(x) do { \
(x) = (u64)ntohl(*p++) << 32; \
(x) |= ntohl(*p++); \
} while (0)
#define READTIME(x) do { \
p++; \
(x.tv_sec) = ntohl(*p++); \
(x.tv_nsec) = ntohl(*p++); \
} while (0)
#define READ_BUF(nbytes) do { \
p = xdr_inline_decode(xdr, nbytes); \
if (!p) { \
dprintk("NFSD: %s: reply buffer overflowed in line %d.\n", \
__FUNCTION__, __LINE__); \
return -EIO; \
} \
} while (0)
struct nfs4_cb_compound_hdr {
int status;
u32 ident;
u32 nops;
u32 taglen;
char * tag;
};
static struct {
int stat;
int errno;
} nfs_cb_errtbl[] = {
{ NFS4_OK, 0 },
{ NFS4ERR_PERM, EPERM },
{ NFS4ERR_NOENT, ENOENT },
{ NFS4ERR_IO, EIO },
{ NFS4ERR_NXIO, ENXIO },
{ NFS4ERR_ACCESS, EACCES },
{ NFS4ERR_EXIST, EEXIST },
{ NFS4ERR_XDEV, EXDEV },
{ NFS4ERR_NOTDIR, ENOTDIR },
{ NFS4ERR_ISDIR, EISDIR },
{ NFS4ERR_INVAL, EINVAL },
{ NFS4ERR_FBIG, EFBIG },
{ NFS4ERR_NOSPC, ENOSPC },
{ NFS4ERR_ROFS, EROFS },
{ NFS4ERR_MLINK, EMLINK },
{ NFS4ERR_NAMETOOLONG, ENAMETOOLONG },
{ NFS4ERR_NOTEMPTY, ENOTEMPTY },
{ NFS4ERR_DQUOT, EDQUOT },
{ NFS4ERR_STALE, ESTALE },
{ NFS4ERR_BADHANDLE, EBADHANDLE },
{ NFS4ERR_BAD_COOKIE, EBADCOOKIE },
{ NFS4ERR_NOTSUPP, ENOTSUPP },
{ NFS4ERR_TOOSMALL, ETOOSMALL },
{ NFS4ERR_SERVERFAULT, ESERVERFAULT },
{ NFS4ERR_BADTYPE, EBADTYPE },
{ NFS4ERR_LOCKED, EAGAIN },
{ NFS4ERR_RESOURCE, EREMOTEIO },
{ NFS4ERR_SYMLINK, ELOOP },
{ NFS4ERR_OP_ILLEGAL, EOPNOTSUPP },
{ NFS4ERR_DEADLOCK, EDEADLK },
{ -1, EIO }
};
static int
nfs_cb_stat_to_errno(int stat)
{
int i;
for (i = 0; nfs_cb_errtbl[i].stat != -1; i++) {
if (nfs_cb_errtbl[i].stat == stat)
return nfs_cb_errtbl[i].errno;
}
/* If we cannot translate the error, the recovery routines should
* handle it.
* Note: remaining NFSv4 error codes have values > 10000, so should
* not conflict with native Linux error codes.
*/
return stat;
}
/*
* XDR encode
*/
static int
encode_cb_compound_hdr(struct xdr_stream *xdr, struct nfs4_cb_compound_hdr *hdr)
{
__be32 * p;
RESERVE_SPACE(16);
WRITE32(0); /* tag length is always 0 */
WRITE32(NFS4_MINOR_VERSION);
WRITE32(hdr->ident);
WRITE32(hdr->nops);
return 0;
}
static int
encode_cb_recall(struct xdr_stream *xdr, struct nfs4_cb_recall *cb_rec)
{
__be32 *p;
int len = cb_rec->cbr_fhlen;
RESERVE_SPACE(12+sizeof(cb_rec->cbr_stateid) + len);
WRITE32(OP_CB_RECALL);
WRITEMEM(&cb_rec->cbr_stateid, sizeof(stateid_t));
WRITE32(cb_rec->cbr_trunc);
WRITE32(len);
WRITEMEM(cb_rec->cbr_fhval, len);
return 0;
}
static int
nfs4_xdr_enc_cb_null(struct rpc_rqst *req, __be32 *p)
{
struct xdr_stream xdrs, *xdr = &xdrs;
xdr_init_encode(&xdrs, &req->rq_snd_buf, p);
RESERVE_SPACE(0);
return 0;
}
static int
nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, __be32 *p, struct nfs4_cb_recall *args)
{
struct xdr_stream xdr;
struct nfs4_cb_compound_hdr hdr = {
.ident = args->cbr_ident,
.nops = 1,
};
xdr_init_encode(&xdr, &req->rq_snd_buf, p);
encode_cb_compound_hdr(&xdr, &hdr);
return (encode_cb_recall(&xdr, args));
}
static int
decode_cb_compound_hdr(struct xdr_stream *xdr, struct nfs4_cb_compound_hdr *hdr){
__be32 *p;
READ_BUF(8);
READ32(hdr->status);
READ32(hdr->taglen);
READ_BUF(hdr->taglen + 4);
hdr->tag = (char *)p;
p += XDR_QUADLEN(hdr->taglen);
READ32(hdr->nops);
return 0;
}
static int
decode_cb_op_hdr(struct xdr_stream *xdr, enum nfs_opnum4 expected)
{
__be32 *p;
u32 op;
int32_t nfserr;
READ_BUF(8);
READ32(op);
if (op != expected) {
dprintk("NFSD: decode_cb_op_hdr: Callback server returned "
" operation %d but we issued a request for %d\n",
op, expected);
return -EIO;
}
READ32(nfserr);
if (nfserr != NFS_OK)
return -nfs_cb_stat_to_errno(nfserr);
return 0;
}
static int
nfs4_xdr_dec_cb_null(struct rpc_rqst *req, __be32 *p)
{
return 0;
}
static int
nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp, __be32 *p)
{
struct xdr_stream xdr;
struct nfs4_cb_compound_hdr hdr;
int status;
xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p);
status = decode_cb_compound_hdr(&xdr, &hdr);
if (status)
goto out;
status = decode_cb_op_hdr(&xdr, OP_CB_RECALL);
out:
return status;
}
/*
* RPC procedure tables
*/
#define PROC(proc, call, argtype, restype) \
[NFSPROC4_CLNT_##proc] = { \
.p_proc = NFSPROC4_CB_##call, \
.p_encode = (kxdrproc_t) nfs4_xdr_##argtype, \
.p_decode = (kxdrproc_t) nfs4_xdr_##restype, \
.p_arglen = NFS4_##argtype##_sz, \
.p_replen = NFS4_##restype##_sz, \
.p_statidx = NFSPROC4_CB_##call, \
.p_name = #proc, \
}
static struct rpc_procinfo nfs4_cb_procedures[] = {
PROC(CB_NULL, NULL, enc_cb_null, dec_cb_null),
PROC(CB_RECALL, COMPOUND, enc_cb_recall, dec_cb_recall),
};
static struct rpc_version nfs_cb_version4 = {
.number = 1,
.nrprocs = ARRAY_SIZE(nfs4_cb_procedures),
.procs = nfs4_cb_procedures
};
static struct rpc_version * nfs_cb_version[] = {
NULL,
&nfs_cb_version4,
};
static struct rpc_program cb_program;
static struct rpc_stat cb_stats = {
.program = &cb_program
};
#define NFS4_CALLBACK 0x40000000
static struct rpc_program cb_program = {
.name = "nfs4_cb",
.number = NFS4_CALLBACK,
.nrvers = ARRAY_SIZE(nfs_cb_version),
.version = nfs_cb_version,
.stats = &cb_stats,
};
/* Reference counting, callback cleanup, etc., all look racy as heck.
* And why is cb_set an atomic? */
static int do_probe_callback(void *data)
{
struct nfs4_client *clp = data;
struct sockaddr_in addr;
struct nfs4_callback *cb = &clp->cl_callback;
struct rpc_timeout timeparms = {
.to_initval = (NFSD_LEASE_TIME/4) * HZ,
.to_retries = 5,
.to_maxval = (NFSD_LEASE_TIME/2) * HZ,
.to_exponential = 1,
};
struct rpc_create_args args = {
.protocol = IPPROTO_TCP,
.address = (struct sockaddr *)&addr,
.addrsize = sizeof(addr),
.timeout = &timeparms,
.program = &cb_program,
.version = nfs_cb_version[1]->number,
.authflavor = RPC_AUTH_UNIX, /* XXX: need AUTH_GSS... */
.flags = (RPC_CLNT_CREATE_NOPING),
};
struct rpc_message msg = {
.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_NULL],
.rpc_argp = clp,
};
struct rpc_clnt *client;
int status;
/* Initialize address */
memset(&addr, 0, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_port = htons(cb->cb_port);
addr.sin_addr.s_addr = htonl(cb->cb_addr);
/* Initialize rpc_stat */
memset(args.program->stats, 0, sizeof(struct rpc_stat));
/* Create RPC client */
client = rpc_create(&args);
if (IS_ERR(client)) {
dprintk("NFSD: couldn't create callback client\n");
status = PTR_ERR(client);
goto out_err;
}
status = rpc_call_sync(client, &msg, RPC_TASK_SOFT);
if (status)
goto out_release_client;
cb->cb_client = client;
atomic_set(&cb->cb_set, 1);
put_nfs4_client(clp);
return 0;
out_release_client:
rpc_shutdown_client(client);
out_err:
put_nfs4_client(clp);
dprintk("NFSD: warning: no callback path to client %.*s\n",
(int)clp->cl_name.len, clp->cl_name.data);
return status;
}
/*
* Set up the callback client and put a NFSPROC4_CB_NULL on the wire...
*/
void
nfsd4_probe_callback(struct nfs4_client *clp)
{
struct task_struct *t;
BUG_ON(atomic_read(&clp->cl_callback.cb_set));
/* the task holds a reference to the nfs4_client struct */
atomic_inc(&clp->cl_count);
t = kthread_run(do_probe_callback, clp, "nfs4_cb_probe");
if (IS_ERR(t))
atomic_dec(&clp->cl_count);
return;
}
/*
* called with dp->dl_count inc'ed.
* nfs4_lock_state() may or may not have been called.
*/
void
nfsd4_cb_recall(struct nfs4_delegation *dp)
{
struct nfs4_client *clp = dp->dl_client;
struct rpc_clnt *clnt = clp->cl_callback.cb_client;
struct nfs4_cb_recall *cbr = &dp->dl_recall;
struct rpc_message msg = {
.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_RECALL],
.rpc_argp = cbr,
};
int retries = 1;
int status = 0;
cbr->cbr_trunc = 0; /* XXX need to implement truncate optimization */
cbr->cbr_dp = dp;
status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFT);
while (retries--) {
switch (status) {
case -EIO:
/* Network partition? */
atomic_set(&clp->cl_callback.cb_set, 0);
case -EBADHANDLE:
case -NFS4ERR_BAD_STATEID:
/* Race: client probably got cb_recall
* before open reply granting delegation */
break;
default:
goto out_put_cred;
}
ssleep(2);
status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFT);
}
out_put_cred:
/*
* Success or failure, now we're either waiting for lease expiration
* or deleg_return.
*/
put_nfs4_client(clp);
nfs4_put_delegation(dp);
return;
}
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