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5ce8ba25d6
linux/fs/nfsd/nfs4callback.c
J. Bruce Fields 5ce8ba25d6 nfsd4: allow restarting callbacks 
If we lose the backchannel and then the client repairs the problem,
resend any callbacks.

We use a new cb_done flag to track whether there is still work to be
done for the callback or whether it can be destroyed with the rpc.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2011-01-11 15:04:11 -05:00

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/*
* 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/sunrpc/clnt.h>
#include <linux/sunrpc/svc_xprt.h>
#include <linux/slab.h>
#include "nfsd.h"
#include "state.h"
#define NFSDDBG_FACILITY NFSDDBG_PROC
#define NFSPROC4_CB_NULL 0
#define NFSPROC4_CB_COMPOUND 1
/* Index of predefined Linux callback client operations */
enum {
NFSPROC4_CLNT_CB_NULL = 0,
NFSPROC4_CLNT_CB_RECALL,
NFSPROC4_CLNT_CB_SEQUENCE,
};
enum nfs_cb_opnum4 {
OP_CB_RECALL = 4,
OP_CB_SEQUENCE = 11,
};
#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 sessionid_sz (NFS4_MAX_SESSIONID_LEN >> 2)
#define cb_sequence_enc_sz (sessionid_sz + 4 + \
1 /* no referring calls list yet */)
#define cb_sequence_dec_sz (op_dec_sz + sessionid_sz + 4)
#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 + \
cb_sequence_enc_sz + \
1 + enc_stateid_sz + \
enc_nfs4_fh_sz)
#define NFS4_dec_cb_recall_sz (cb_compound_dec_hdr_sz + \
cb_sequence_dec_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), __func__); \
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", \
__func__, __LINE__); \
return -EIO; \
} \
} while (0)
struct nfs4_cb_compound_hdr {
/* args */
u32 ident; /* minorversion 0 only */
u32 nops;
__be32 *nops_p;
u32 minorversion;
/* res */
int status;
};
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 void
encode_stateid(struct xdr_stream *xdr, stateid_t *sid)
{
__be32 *p;
RESERVE_SPACE(sizeof(stateid_t));
WRITE32(sid->si_generation);
WRITEMEM(&sid->si_opaque, sizeof(stateid_opaque_t));
}
static void
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(hdr->minorversion);
WRITE32(hdr->ident);
hdr->nops_p = p;
WRITE32(hdr->nops);
}
static void encode_cb_nops(struct nfs4_cb_compound_hdr *hdr)
{
*hdr->nops_p = htonl(hdr->nops);
}
static void
encode_cb_recall(struct xdr_stream *xdr, struct nfs4_delegation *dp,
struct nfs4_cb_compound_hdr *hdr)
{
__be32 *p;
int len = dp->dl_fh.fh_size;
RESERVE_SPACE(4);
WRITE32(OP_CB_RECALL);
encode_stateid(xdr, &dp->dl_stateid);
RESERVE_SPACE(8 + (XDR_QUADLEN(len) << 2));
WRITE32(0); /* truncate optimization not implemented */
WRITE32(len);
WRITEMEM(&dp->dl_fh.fh_base, len);
hdr->nops++;
}
static void
encode_cb_sequence(struct xdr_stream *xdr, struct nfsd4_callback *cb,
struct nfs4_cb_compound_hdr *hdr)
{
__be32 *p;
struct nfsd4_session *ses = cb->cb_clp->cl_cb_session;
if (hdr->minorversion == 0)
return;
RESERVE_SPACE(1 + NFS4_MAX_SESSIONID_LEN + 20);
WRITE32(OP_CB_SEQUENCE);
WRITEMEM(ses->se_sessionid.data, NFS4_MAX_SESSIONID_LEN);
WRITE32(ses->se_cb_seq_nr);
WRITE32(0); /* slotid, always 0 */
WRITE32(0); /* highest slotid always 0 */
WRITE32(0); /* cachethis always 0 */
WRITE32(0); /* FIXME: support referring_call_lists */
hdr->nops++;
}
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 nfsd4_callback *cb)
{
struct xdr_stream xdr;
struct nfs4_delegation *args = cb->cb_op;
struct nfs4_cb_compound_hdr hdr = {
.ident = cb->cb_clp->cl_cb_ident,
.minorversion = cb->cb_minorversion,
};
xdr_init_encode(&xdr, &req->rq_snd_buf, p);
encode_cb_compound_hdr(&xdr, &hdr);
encode_cb_sequence(&xdr, cb, &hdr);
encode_cb_recall(&xdr, args, &hdr);
encode_cb_nops(&hdr);
return 0;
}
static int
decode_cb_compound_hdr(struct xdr_stream *xdr, struct nfs4_cb_compound_hdr *hdr){
__be32 *p;
u32 taglen;
READ_BUF(8);
READ32(hdr->status);
/* We've got no use for the tag; ignore it: */
READ32(taglen);
READ_BUF(taglen + 4);
p += XDR_QUADLEN(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;
}
/*
* Our current back channel implmentation supports a single backchannel
* with a single slot.
*/
static int
decode_cb_sequence(struct xdr_stream *xdr, struct nfsd4_callback *cb,
struct rpc_rqst *rqstp)
{
struct nfsd4_session *ses = cb->cb_clp->cl_cb_session;
struct nfs4_sessionid id;
int status;
u32 dummy;
__be32 *p;
if (cb->cb_minorversion == 0)
return 0;
status = decode_cb_op_hdr(xdr, OP_CB_SEQUENCE);
if (status)
return status;
/*
* If the server returns different values for sessionID, slotID or
* sequence number, the server is looney tunes.
*/
status = -ESERVERFAULT;
READ_BUF(NFS4_MAX_SESSIONID_LEN + 16);
memcpy(id.data, p, NFS4_MAX_SESSIONID_LEN);
p += XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN);
if (memcmp(id.data, ses->se_sessionid.data, NFS4_MAX_SESSIONID_LEN)) {
dprintk("%s Invalid session id\n", __func__);
goto out;
}
READ32(dummy);
if (dummy != ses->se_cb_seq_nr) {
dprintk("%s Invalid sequence number\n", __func__);
goto out;
}
READ32(dummy); /* slotid must be 0 */
if (dummy != 0) {
dprintk("%s Invalid slotid\n", __func__);
goto out;
}
/* FIXME: process highest slotid and target highest slotid */
status = 0;
out:
return status;
}
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 nfsd4_callback *cb)
{
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;
if (cb) {
status = decode_cb_sequence(&xdr, cb, rqstp);
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 = {
/*
* Note on the callback rpc program version number: despite language in rfc
* 5661 section 18.36.3 requiring servers to use 4 in this field, the
* official xdr descriptions for both 4.0 and 4.1 specify version 1, and
* in practice that appears to be what implementations use. The section
* 18.36.3 language is expected to be fixed in an erratum.
*/
.number = 1,
.nrprocs = ARRAY_SIZE(nfs4_cb_procedures),
.procs = nfs4_cb_procedures
};
static struct rpc_version * nfs_cb_version[] = {
&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,
.pipe_dir_name = "/nfsd4_cb",
};
static int max_cb_time(void)
{
return max(nfsd4_lease/10, (time_t)1) * HZ;
}
static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn, struct nfsd4_session *ses)
{
struct rpc_timeout timeparms = {
.to_initval = max_cb_time(),
.to_retries = 0,
};
struct rpc_create_args args = {
.net = &init_net,
.address = (struct sockaddr *) &conn->cb_addr,
.addrsize = conn->cb_addrlen,
.saddress = (struct sockaddr *) &conn->cb_saddr,
.timeout = &timeparms,
.program = &cb_program,
.version = 0,
.authflavor = clp->cl_flavor,
.flags = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
};
struct rpc_clnt *client;
if (clp->cl_minorversion == 0) {
if (!clp->cl_principal && (clp->cl_flavor >= RPC_AUTH_GSS_KRB5))
return -EINVAL;
args.client_name = clp->cl_principal;
args.prognumber = conn->cb_prog,
args.protocol = XPRT_TRANSPORT_TCP;
clp->cl_cb_ident = conn->cb_ident;
} else {
if (!conn->cb_xprt)
return -EINVAL;
clp->cl_cb_conn.cb_xprt = conn->cb_xprt;
clp->cl_cb_session = ses;
args.bc_xprt = conn->cb_xprt;
args.prognumber = clp->cl_cb_session->se_cb_prog;
args.protocol = XPRT_TRANSPORT_BC_TCP;
}
/* Create RPC client */
client = rpc_create(&args);
if (IS_ERR(client)) {
dprintk("NFSD: couldn't create callback client: %ld\n",
PTR_ERR(client));
return PTR_ERR(client);
}
clp->cl_cb_client = client;
return 0;
}
static void warn_no_callback_path(struct nfs4_client *clp, int reason)
{
dprintk("NFSD: warning: no callback path to client %.*s: error %d\n",
(int)clp->cl_name.len, clp->cl_name.data, reason);
}
static void nfsd4_mark_cb_down(struct nfs4_client *clp, int reason)
{
clp->cl_cb_state = NFSD4_CB_DOWN;
warn_no_callback_path(clp, reason);
}
static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
{
struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
if (task->tk_status)
nfsd4_mark_cb_down(clp, task->tk_status);
else
clp->cl_cb_state = NFSD4_CB_UP;
}
static const struct rpc_call_ops nfsd4_cb_probe_ops = {
/* XXX: release method to ensure we set the cb channel down if
* necessary on early failure? */
.rpc_call_done = nfsd4_cb_probe_done,
};
static struct rpc_cred *callback_cred;
int set_callback_cred(void)
{
if (callback_cred)
return 0;
callback_cred = rpc_lookup_machine_cred();
if (!callback_cred)
return -ENOMEM;
return 0;
}
static struct workqueue_struct *callback_wq;
static void run_nfsd4_cb(struct nfsd4_callback *cb)
{
queue_work(callback_wq, &cb->cb_work);
}
static void do_probe_callback(struct nfs4_client *clp)
{
struct nfsd4_callback *cb = &clp->cl_cb_null;
cb->cb_op = NULL;
cb->cb_clp = clp;
cb->cb_msg.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_NULL];
cb->cb_msg.rpc_argp = NULL;
cb->cb_msg.rpc_resp = NULL;
cb->cb_msg.rpc_cred = callback_cred;
cb->cb_ops = &nfsd4_cb_probe_ops;
run_nfsd4_cb(cb);
}
/*
* Poke the callback thread to process any updates to the callback
* parameters, and send a null probe.
*/
void nfsd4_probe_callback(struct nfs4_client *clp)
{
/* XXX: atomicity? Also, should we be using cl_cb_flags? */
clp->cl_cb_state = NFSD4_CB_UNKNOWN;
set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_cb_flags);
do_probe_callback(clp);
}
void nfsd4_probe_callback_sync(struct nfs4_client *clp)
{
nfsd4_probe_callback(clp);
flush_workqueue(callback_wq);
}
void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *conn)
{
clp->cl_cb_state = NFSD4_CB_UNKNOWN;
spin_lock(&clp->cl_lock);
memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn));
spin_unlock(&clp->cl_lock);
}
/*
* There's currently a single callback channel slot.
* If the slot is available, then mark it busy. Otherwise, set the
* thread for sleeping on the callback RPC wait queue.
*/
static bool nfsd41_cb_get_slot(struct nfs4_client *clp, struct rpc_task *task)
{
if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
dprintk("%s slot is busy\n", __func__);
return false;
}
return true;
}
/*
* TODO: cb_sequence should support referring call lists, cachethis, multiple
* slots, and mark callback channel down on communication errors.
*/
static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
{
struct nfsd4_callback *cb = calldata;
struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
struct nfs4_client *clp = dp->dl_client;
u32 minorversion = clp->cl_minorversion;
cb->cb_minorversion = minorversion;
if (minorversion) {
if (!nfsd41_cb_get_slot(clp, task))
return;
}
cb->cb_done = false;
spin_lock(&clp->cl_lock);
list_add(&cb->cb_per_client, &clp->cl_callbacks);
spin_unlock(&clp->cl_lock);
rpc_call_start(task);
}
static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
{
struct nfsd4_callback *cb = calldata;
struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
struct nfs4_client *clp = dp->dl_client;
dprintk("%s: minorversion=%d\n", __func__,
clp->cl_minorversion);
if (clp->cl_minorversion) {
/* No need for lock, access serialized in nfsd4_cb_prepare */
++clp->cl_cb_session->se_cb_seq_nr;
clear_bit(0, &clp->cl_cb_slot_busy);
rpc_wake_up_next(&clp->cl_cb_waitq);
dprintk("%s: freed slot, new seqid=%d\n", __func__,
clp->cl_cb_session->se_cb_seq_nr);
/* We're done looking into the sequence information */
task->tk_msg.rpc_resp = NULL;
}
}
static void nfsd4_cb_recall_done(struct rpc_task *task, void *calldata)
{
struct nfsd4_callback *cb = calldata;
struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
struct nfs4_client *clp = dp->dl_client;
struct rpc_clnt *current_rpc_client = clp->cl_cb_client;
nfsd4_cb_done(task, calldata);
if (current_rpc_client == NULL) {
/* We're shutting down; give up. */
/* XXX: err, or is it ok just to fall through
* and rpc_restart_call? */
return;
}
if (cb->cb_done)
return;
switch (task->tk_status) {
case 0:
cb->cb_done = true;
return;
case -EBADHANDLE:
case -NFS4ERR_BAD_STATEID:
/* Race: client probably got cb_recall
* before open reply granting delegation */
break;
default:
/* Network partition? */
nfsd4_mark_cb_down(clp, task->tk_status);
if (current_rpc_client != task->tk_client) {
/* queue a callback on the new connection: */
atomic_inc(&dp->dl_count);
run_nfsd4_cb(&dp->dl_recall);
return;
}
}
if (dp->dl_retries--) {
rpc_delay(task, 2*HZ);
task->tk_status = 0;
rpc_restart_call_prepare(task);
return;
}
nfsd4_mark_cb_down(clp, task->tk_status);
cb->cb_done = true;
}
static void nfsd4_cb_recall_release(void *calldata)
{
struct nfsd4_callback *cb = calldata;
struct nfs4_client *clp = cb->cb_clp;
struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
if (cb->cb_done) {
spin_lock(&clp->cl_lock);
list_del(&cb->cb_per_client);
spin_unlock(&clp->cl_lock);
nfs4_put_delegation(dp);
}
}
static const struct rpc_call_ops nfsd4_cb_recall_ops = {
.rpc_call_prepare = nfsd4_cb_prepare,
.rpc_call_done = nfsd4_cb_recall_done,
.rpc_release = nfsd4_cb_recall_release,
};
int nfsd4_create_callback_queue(void)
{
callback_wq = create_singlethread_workqueue("nfsd4_callbacks");
if (!callback_wq)
return -ENOMEM;
return 0;
}
void nfsd4_destroy_callback_queue(void)
{
destroy_workqueue(callback_wq);
}
/* must be called under the state lock */
void nfsd4_shutdown_callback(struct nfs4_client *clp)
{
set_bit(NFSD4_CLIENT_KILL, &clp->cl_cb_flags);
/*
* Note this won't actually result in a null callback;
* instead, nfsd4_do_callback_rpc() will detect the killed
* client, destroy the rpc client, and stop:
*/
do_probe_callback(clp);
flush_workqueue(callback_wq);
}
static void nfsd4_release_cb(struct nfsd4_callback *cb)
{
if (cb->cb_ops->rpc_release)
cb->cb_ops->rpc_release(cb);
}
/* requires cl_lock: */
static struct nfsd4_conn * __nfsd4_find_backchannel(struct nfs4_client *clp)
{
struct nfsd4_session *s;
struct nfsd4_conn *c;
list_for_each_entry(s, &clp->cl_sessions, se_perclnt) {
list_for_each_entry(c, &s->se_conns, cn_persession) {
if (c->cn_flags & NFS4_CDFC4_BACK)
return c;
}
}
return NULL;
}
static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
{
struct nfs4_cb_conn conn;
struct nfs4_client *clp = cb->cb_clp;
struct nfsd4_session *ses = NULL;
struct nfsd4_conn *c;
int err;
/*
* This is either an update, or the client dying; in either case,
* kill the old client:
*/
if (clp->cl_cb_client) {
rpc_shutdown_client(clp->cl_cb_client);
clp->cl_cb_client = NULL;
}
if (clp->cl_cb_conn.cb_xprt) {
svc_xprt_put(clp->cl_cb_conn.cb_xprt);
clp->cl_cb_conn.cb_xprt = NULL;
}
if (test_bit(NFSD4_CLIENT_KILL, &clp->cl_cb_flags))
return;
spin_lock(&clp->cl_lock);
/*
* Only serialized callback code is allowed to clear these
* flags; main nfsd code can only set them:
*/
BUG_ON(!clp->cl_cb_flags);
clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_cb_flags);
memcpy(&conn, &cb->cb_clp->cl_cb_conn, sizeof(struct nfs4_cb_conn));
c = __nfsd4_find_backchannel(clp);
if (c) {
svc_xprt_get(c->cn_xprt);
conn.cb_xprt = c->cn_xprt;
ses = c->cn_session;
}
spin_unlock(&clp->cl_lock);
err = setup_callback_client(clp, &conn, ses);
if (err) {
warn_no_callback_path(clp, err);
return;
}
/* Yay, the callback channel's back! Restart any callbacks: */
list_for_each_entry(cb, &clp->cl_callbacks, cb_per_client)
run_nfsd4_cb(cb);
}
void nfsd4_do_callback_rpc(struct work_struct *w)
{
struct nfsd4_callback *cb = container_of(w, struct nfsd4_callback, cb_work);
struct nfs4_client *clp = cb->cb_clp;
struct rpc_clnt *clnt;
if (clp->cl_cb_flags)
nfsd4_process_cb_update(cb);
clnt = clp->cl_cb_client;
if (!clnt) {
/* Callback channel broken, or client killed; give up: */
nfsd4_release_cb(cb);
return;
}
rpc_call_async(clnt, &cb->cb_msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN,
cb->cb_ops, cb);
}
void nfsd4_cb_recall(struct nfs4_delegation *dp)
{
struct nfsd4_callback *cb = &dp->dl_recall;
struct nfs4_client *clp = dp->dl_client;
dp->dl_retries = 1;
cb->cb_op = dp;
cb->cb_clp = clp;
cb->cb_msg.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_RECALL];
cb->cb_msg.rpc_argp = cb;
cb->cb_msg.rpc_resp = cb;
cb->cb_msg.rpc_cred = callback_cred;
cb->cb_ops = &nfsd4_cb_recall_ops;
dp->dl_retries = 1;
cb->cb_done = true;
run_nfsd4_cb(&dp->dl_recall);
}
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