Root/fs/nfsd/nfs4callback.c

1/*
2 * Copyright (c) 2001 The Regents of the University of Michigan.
3 * All rights reserved.
4 *
5 * Kendrick Smith <kmsmith@umich.edu>
6 * Andy Adamson <andros@umich.edu>
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the University nor the names of its
18 * contributors may be used to endorse or promote products derived
19 * from this software without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
22 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
23 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
24 * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
28 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
29 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
30 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
31 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 */
33
34#include <linux/sunrpc/clnt.h>
35#include <linux/sunrpc/svc_xprt.h>
36#include <linux/slab.h>
37#include "nfsd.h"
38#include "state.h"
39
40#define NFSDDBG_FACILITY NFSDDBG_PROC
41
42#define NFSPROC4_CB_NULL 0
43#define NFSPROC4_CB_COMPOUND 1
44
45/* Index of predefined Linux callback client operations */
46
47enum {
48    NFSPROC4_CLNT_CB_NULL = 0,
49    NFSPROC4_CLNT_CB_RECALL,
50    NFSPROC4_CLNT_CB_SEQUENCE,
51};
52
53#define NFS4_MAXTAGLEN 20
54
55#define NFS4_enc_cb_null_sz 0
56#define NFS4_dec_cb_null_sz 0
57#define cb_compound_enc_hdr_sz 4
58#define cb_compound_dec_hdr_sz (3 + (NFS4_MAXTAGLEN >> 2))
59#define sessionid_sz (NFS4_MAX_SESSIONID_LEN >> 2)
60#define cb_sequence_enc_sz (sessionid_sz + 4 + \
61                    1 /* no referring calls list yet */)
62#define cb_sequence_dec_sz (op_dec_sz + sessionid_sz + 4)
63
64#define op_enc_sz 1
65#define op_dec_sz 2
66#define enc_nfs4_fh_sz (1 + (NFS4_FHSIZE >> 2))
67#define enc_stateid_sz (NFS4_STATEID_SIZE >> 2)
68#define NFS4_enc_cb_recall_sz (cb_compound_enc_hdr_sz + \
69                    cb_sequence_enc_sz + \
70                    1 + enc_stateid_sz + \
71                    enc_nfs4_fh_sz)
72
73#define NFS4_dec_cb_recall_sz (cb_compound_dec_hdr_sz + \
74                    cb_sequence_dec_sz + \
75                    op_dec_sz)
76
77struct nfs4_cb_compound_hdr {
78    /* args */
79    u32 ident; /* minorversion 0 only */
80    u32 nops;
81    __be32 *nops_p;
82    u32 minorversion;
83    /* res */
84    int status;
85};
86
87/*
88 * Handle decode buffer overflows out-of-line.
89 */
90static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
91{
92    dprintk("NFS: %s prematurely hit the end of our receive buffer. "
93        "Remaining buffer length is %tu words.\n",
94        func, xdr->end - xdr->p);
95}
96
97static __be32 *xdr_encode_empty_array(__be32 *p)
98{
99    *p++ = xdr_zero;
100    return p;
101}
102
103/*
104 * Encode/decode NFSv4 CB basic data types
105 *
106 * Basic NFSv4 callback data types are defined in section 15 of RFC
107 * 3530: "Network File System (NFS) version 4 Protocol" and section
108 * 20 of RFC 5661: "Network File System (NFS) Version 4 Minor Version
109 * 1 Protocol"
110 */
111
112/*
113 * nfs_cb_opnum4
114 *
115 * enum nfs_cb_opnum4 {
116 * OP_CB_GETATTR = 3,
117 * ...
118 * };
119 */
120enum nfs_cb_opnum4 {
121    OP_CB_GETATTR = 3,
122    OP_CB_RECALL = 4,
123    OP_CB_LAYOUTRECALL = 5,
124    OP_CB_NOTIFY = 6,
125    OP_CB_PUSH_DELEG = 7,
126    OP_CB_RECALL_ANY = 8,
127    OP_CB_RECALLABLE_OBJ_AVAIL = 9,
128    OP_CB_RECALL_SLOT = 10,
129    OP_CB_SEQUENCE = 11,
130    OP_CB_WANTS_CANCELLED = 12,
131    OP_CB_NOTIFY_LOCK = 13,
132    OP_CB_NOTIFY_DEVICEID = 14,
133    OP_CB_ILLEGAL = 10044
134};
135
136static void encode_nfs_cb_opnum4(struct xdr_stream *xdr, enum nfs_cb_opnum4 op)
137{
138    __be32 *p;
139
140    p = xdr_reserve_space(xdr, 4);
141    *p = cpu_to_be32(op);
142}
143
144/*
145 * nfs_fh4
146 *
147 * typedef opaque nfs_fh4<NFS4_FHSIZE>;
148 */
149static void encode_nfs_fh4(struct xdr_stream *xdr, const struct knfsd_fh *fh)
150{
151    u32 length = fh->fh_size;
152    __be32 *p;
153
154    BUG_ON(length > NFS4_FHSIZE);
155    p = xdr_reserve_space(xdr, 4 + length);
156    xdr_encode_opaque(p, &fh->fh_base, length);
157}
158
159/*
160 * stateid4
161 *
162 * struct stateid4 {
163 * uint32_t seqid;
164 * opaque other[12];
165 * };
166 */
167static void encode_stateid4(struct xdr_stream *xdr, const stateid_t *sid)
168{
169    __be32 *p;
170
171    p = xdr_reserve_space(xdr, NFS4_STATEID_SIZE);
172    *p++ = cpu_to_be32(sid->si_generation);
173    xdr_encode_opaque_fixed(p, &sid->si_opaque, NFS4_STATEID_OTHER_SIZE);
174}
175
176/*
177 * sessionid4
178 *
179 * typedef opaque sessionid4[NFS4_SESSIONID_SIZE];
180 */
181static void encode_sessionid4(struct xdr_stream *xdr,
182                  const struct nfsd4_session *session)
183{
184    __be32 *p;
185
186    p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN);
187    xdr_encode_opaque_fixed(p, session->se_sessionid.data,
188                    NFS4_MAX_SESSIONID_LEN);
189}
190
191/*
192 * nfsstat4
193 */
194static const struct {
195    int stat;
196    int errno;
197} nfs_cb_errtbl[] = {
198    { NFS4_OK, 0 },
199    { NFS4ERR_PERM, -EPERM },
200    { NFS4ERR_NOENT, -ENOENT },
201    { NFS4ERR_IO, -EIO },
202    { NFS4ERR_NXIO, -ENXIO },
203    { NFS4ERR_ACCESS, -EACCES },
204    { NFS4ERR_EXIST, -EEXIST },
205    { NFS4ERR_XDEV, -EXDEV },
206    { NFS4ERR_NOTDIR, -ENOTDIR },
207    { NFS4ERR_ISDIR, -EISDIR },
208    { NFS4ERR_INVAL, -EINVAL },
209    { NFS4ERR_FBIG, -EFBIG },
210    { NFS4ERR_NOSPC, -ENOSPC },
211    { NFS4ERR_ROFS, -EROFS },
212    { NFS4ERR_MLINK, -EMLINK },
213    { NFS4ERR_NAMETOOLONG, -ENAMETOOLONG },
214    { NFS4ERR_NOTEMPTY, -ENOTEMPTY },
215    { NFS4ERR_DQUOT, -EDQUOT },
216    { NFS4ERR_STALE, -ESTALE },
217    { NFS4ERR_BADHANDLE, -EBADHANDLE },
218    { NFS4ERR_BAD_COOKIE, -EBADCOOKIE },
219    { NFS4ERR_NOTSUPP, -ENOTSUPP },
220    { NFS4ERR_TOOSMALL, -ETOOSMALL },
221    { NFS4ERR_SERVERFAULT, -ESERVERFAULT },
222    { NFS4ERR_BADTYPE, -EBADTYPE },
223    { NFS4ERR_LOCKED, -EAGAIN },
224    { NFS4ERR_RESOURCE, -EREMOTEIO },
225    { NFS4ERR_SYMLINK, -ELOOP },
226    { NFS4ERR_OP_ILLEGAL, -EOPNOTSUPP },
227    { NFS4ERR_DEADLOCK, -EDEADLK },
228    { -1, -EIO }
229};
230
231/*
232 * If we cannot translate the error, the recovery routines should
233 * handle it.
234 *
235 * Note: remaining NFSv4 error codes have values > 10000, so should
236 * not conflict with native Linux error codes.
237 */
238static int nfs_cb_stat_to_errno(int status)
239{
240    int i;
241
242    for (i = 0; nfs_cb_errtbl[i].stat != -1; i++) {
243        if (nfs_cb_errtbl[i].stat == status)
244            return nfs_cb_errtbl[i].errno;
245    }
246
247    dprintk("NFSD: Unrecognized NFS CB status value: %u\n", status);
248    return -status;
249}
250
251static int decode_cb_op_status(struct xdr_stream *xdr, enum nfs_opnum4 expected,
252                   enum nfsstat4 *status)
253{
254    __be32 *p;
255    u32 op;
256
257    p = xdr_inline_decode(xdr, 4 + 4);
258    if (unlikely(p == NULL))
259        goto out_overflow;
260    op = be32_to_cpup(p++);
261    if (unlikely(op != expected))
262        goto out_unexpected;
263    *status = be32_to_cpup(p);
264    return 0;
265out_overflow:
266    print_overflow_msg(__func__, xdr);
267    return -EIO;
268out_unexpected:
269    dprintk("NFSD: Callback server returned operation %d but "
270        "we issued a request for %d\n", op, expected);
271    return -EIO;
272}
273
274/*
275 * CB_COMPOUND4args
276 *
277 * struct CB_COMPOUND4args {
278 * utf8str_cs tag;
279 * uint32_t minorversion;
280 * uint32_t callback_ident;
281 * nfs_cb_argop4 argarray<>;
282 * };
283*/
284static void encode_cb_compound4args(struct xdr_stream *xdr,
285                    struct nfs4_cb_compound_hdr *hdr)
286{
287    __be32 * p;
288
289    p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4);
290    p = xdr_encode_empty_array(p); /* empty tag */
291    *p++ = cpu_to_be32(hdr->minorversion);
292    *p++ = cpu_to_be32(hdr->ident);
293
294    hdr->nops_p = p;
295    *p = cpu_to_be32(hdr->nops); /* argarray element count */
296}
297
298/*
299 * Update argarray element count
300 */
301static void encode_cb_nops(struct nfs4_cb_compound_hdr *hdr)
302{
303    BUG_ON(hdr->nops > NFS4_MAX_BACK_CHANNEL_OPS);
304    *hdr->nops_p = cpu_to_be32(hdr->nops);
305}
306
307/*
308 * CB_COMPOUND4res
309 *
310 * struct CB_COMPOUND4res {
311 * nfsstat4 status;
312 * utf8str_cs tag;
313 * nfs_cb_resop4 resarray<>;
314 * };
315 */
316static int decode_cb_compound4res(struct xdr_stream *xdr,
317                  struct nfs4_cb_compound_hdr *hdr)
318{
319    u32 length;
320    __be32 *p;
321
322    p = xdr_inline_decode(xdr, 4 + 4);
323    if (unlikely(p == NULL))
324        goto out_overflow;
325    hdr->status = be32_to_cpup(p++);
326    /* Ignore the tag */
327    length = be32_to_cpup(p++);
328    p = xdr_inline_decode(xdr, length + 4);
329    if (unlikely(p == NULL))
330        goto out_overflow;
331    hdr->nops = be32_to_cpup(p);
332    return 0;
333out_overflow:
334    print_overflow_msg(__func__, xdr);
335    return -EIO;
336}
337
338/*
339 * CB_RECALL4args
340 *
341 * struct CB_RECALL4args {
342 * stateid4 stateid;
343 * bool truncate;
344 * nfs_fh4 fh;
345 * };
346 */
347static void encode_cb_recall4args(struct xdr_stream *xdr,
348                  const struct nfs4_delegation *dp,
349                  struct nfs4_cb_compound_hdr *hdr)
350{
351    __be32 *p;
352
353    encode_nfs_cb_opnum4(xdr, OP_CB_RECALL);
354    encode_stateid4(xdr, &dp->dl_stateid);
355
356    p = xdr_reserve_space(xdr, 4);
357    *p++ = xdr_zero; /* truncate */
358
359    encode_nfs_fh4(xdr, &dp->dl_fh);
360
361    hdr->nops++;
362}
363
364/*
365 * CB_SEQUENCE4args
366 *
367 * struct CB_SEQUENCE4args {
368 * sessionid4 csa_sessionid;
369 * sequenceid4 csa_sequenceid;
370 * slotid4 csa_slotid;
371 * slotid4 csa_highest_slotid;
372 * bool csa_cachethis;
373 * referring_call_list4 csa_referring_call_lists<>;
374 * };
375 */
376static void encode_cb_sequence4args(struct xdr_stream *xdr,
377                    const struct nfsd4_callback *cb,
378                    struct nfs4_cb_compound_hdr *hdr)
379{
380    struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
381    __be32 *p;
382
383    if (hdr->minorversion == 0)
384        return;
385
386    encode_nfs_cb_opnum4(xdr, OP_CB_SEQUENCE);
387    encode_sessionid4(xdr, session);
388
389    p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4 + 4);
390    *p++ = cpu_to_be32(session->se_cb_seq_nr); /* csa_sequenceid */
391    *p++ = xdr_zero; /* csa_slotid */
392    *p++ = xdr_zero; /* csa_highest_slotid */
393    *p++ = xdr_zero; /* csa_cachethis */
394    xdr_encode_empty_array(p); /* csa_referring_call_lists */
395
396    hdr->nops++;
397}
398
399/*
400 * CB_SEQUENCE4resok
401 *
402 * struct CB_SEQUENCE4resok {
403 * sessionid4 csr_sessionid;
404 * sequenceid4 csr_sequenceid;
405 * slotid4 csr_slotid;
406 * slotid4 csr_highest_slotid;
407 * slotid4 csr_target_highest_slotid;
408 * };
409 *
410 * union CB_SEQUENCE4res switch (nfsstat4 csr_status) {
411 * case NFS4_OK:
412 * CB_SEQUENCE4resok csr_resok4;
413 * default:
414 * void;
415 * };
416 *
417 * Our current back channel implmentation supports a single backchannel
418 * with a single slot.
419 */
420static int decode_cb_sequence4resok(struct xdr_stream *xdr,
421                    struct nfsd4_callback *cb)
422{
423    struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
424    struct nfs4_sessionid id;
425    int status;
426    __be32 *p;
427    u32 dummy;
428
429    status = -ESERVERFAULT;
430
431    /*
432     * If the server returns different values for sessionID, slotID or
433     * sequence number, the server is looney tunes.
434     */
435    p = xdr_inline_decode(xdr, NFS4_MAX_SESSIONID_LEN + 4 + 4 + 4 + 4);
436    if (unlikely(p == NULL))
437        goto out_overflow;
438    memcpy(id.data, p, NFS4_MAX_SESSIONID_LEN);
439    if (memcmp(id.data, session->se_sessionid.data,
440                    NFS4_MAX_SESSIONID_LEN) != 0) {
441        dprintk("NFS: %s Invalid session id\n", __func__);
442        goto out;
443    }
444    p += XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN);
445
446    dummy = be32_to_cpup(p++);
447    if (dummy != session->se_cb_seq_nr) {
448        dprintk("NFS: %s Invalid sequence number\n", __func__);
449        goto out;
450    }
451
452    dummy = be32_to_cpup(p++);
453    if (dummy != 0) {
454        dprintk("NFS: %s Invalid slotid\n", __func__);
455        goto out;
456    }
457
458    /*
459     * FIXME: process highest slotid and target highest slotid
460     */
461    status = 0;
462out:
463    return status;
464out_overflow:
465    print_overflow_msg(__func__, xdr);
466    return -EIO;
467}
468
469static int decode_cb_sequence4res(struct xdr_stream *xdr,
470                  struct nfsd4_callback *cb)
471{
472    enum nfsstat4 nfserr;
473    int status;
474
475    if (cb->cb_minorversion == 0)
476        return 0;
477
478    status = decode_cb_op_status(xdr, OP_CB_SEQUENCE, &nfserr);
479    if (unlikely(status))
480        goto out;
481    if (unlikely(nfserr != NFS4_OK))
482        goto out_default;
483    status = decode_cb_sequence4resok(xdr, cb);
484out:
485    return status;
486out_default:
487    return nfs_cb_stat_to_errno(nfserr);
488}
489
490/*
491 * NFSv4.0 and NFSv4.1 XDR encode functions
492 *
493 * NFSv4.0 callback argument types are defined in section 15 of RFC
494 * 3530: "Network File System (NFS) version 4 Protocol" and section 20
495 * of RFC 5661: "Network File System (NFS) Version 4 Minor Version 1
496 * Protocol".
497 */
498
499/*
500 * NB: Without this zero space reservation, callbacks over krb5p fail
501 */
502static void nfs4_xdr_enc_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
503                 void *__unused)
504{
505    xdr_reserve_space(xdr, 0);
506}
507
508/*
509 * 20.2. Operation 4: CB_RECALL - Recall a Delegation
510 */
511static void nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, struct xdr_stream *xdr,
512                   const struct nfsd4_callback *cb)
513{
514    const struct nfs4_delegation *args = cb->cb_op;
515    struct nfs4_cb_compound_hdr hdr = {
516        .ident = cb->cb_clp->cl_cb_ident,
517        .minorversion = cb->cb_minorversion,
518    };
519
520    encode_cb_compound4args(xdr, &hdr);
521    encode_cb_sequence4args(xdr, cb, &hdr);
522    encode_cb_recall4args(xdr, args, &hdr);
523    encode_cb_nops(&hdr);
524}
525
526
527/*
528 * NFSv4.0 and NFSv4.1 XDR decode functions
529 *
530 * NFSv4.0 callback result types are defined in section 15 of RFC
531 * 3530: "Network File System (NFS) version 4 Protocol" and section 20
532 * of RFC 5661: "Network File System (NFS) Version 4 Minor Version 1
533 * Protocol".
534 */
535
536static int nfs4_xdr_dec_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
537                void *__unused)
538{
539    return 0;
540}
541
542/*
543 * 20.2. Operation 4: CB_RECALL - Recall a Delegation
544 */
545static int nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp,
546                  struct xdr_stream *xdr,
547                  struct nfsd4_callback *cb)
548{
549    struct nfs4_cb_compound_hdr hdr;
550    enum nfsstat4 nfserr;
551    int status;
552
553    status = decode_cb_compound4res(xdr, &hdr);
554    if (unlikely(status))
555        goto out;
556
557    if (cb != NULL) {
558        status = decode_cb_sequence4res(xdr, cb);
559        if (unlikely(status))
560            goto out;
561    }
562
563    status = decode_cb_op_status(xdr, OP_CB_RECALL, &nfserr);
564    if (unlikely(status))
565        goto out;
566    if (unlikely(nfserr != NFS4_OK))
567        status = nfs_cb_stat_to_errno(nfserr);
568out:
569    return status;
570}
571
572/*
573 * RPC procedure tables
574 */
575#define PROC(proc, call, argtype, restype) \
576[NFSPROC4_CLNT_##proc] = { \
577    .p_proc = NFSPROC4_CB_##call, \
578    .p_encode = (kxdreproc_t)nfs4_xdr_enc_##argtype, \
579    .p_decode = (kxdrdproc_t)nfs4_xdr_dec_##restype, \
580    .p_arglen = NFS4_enc_##argtype##_sz, \
581    .p_replen = NFS4_dec_##restype##_sz, \
582    .p_statidx = NFSPROC4_CB_##call, \
583    .p_name = #proc, \
584}
585
586static struct rpc_procinfo nfs4_cb_procedures[] = {
587    PROC(CB_NULL, NULL, cb_null, cb_null),
588    PROC(CB_RECALL, COMPOUND, cb_recall, cb_recall),
589};
590
591static struct rpc_version nfs_cb_version4 = {
592/*
593 * Note on the callback rpc program version number: despite language in rfc
594 * 5661 section 18.36.3 requiring servers to use 4 in this field, the
595 * official xdr descriptions for both 4.0 and 4.1 specify version 1, and
596 * in practice that appears to be what implementations use. The section
597 * 18.36.3 language is expected to be fixed in an erratum.
598 */
599    .number = 1,
600    .nrprocs = ARRAY_SIZE(nfs4_cb_procedures),
601    .procs = nfs4_cb_procedures
602};
603
604static struct rpc_version *nfs_cb_version[] = {
605    &nfs_cb_version4,
606};
607
608static struct rpc_program cb_program;
609
610static struct rpc_stat cb_stats = {
611    .program = &cb_program
612};
613
614#define NFS4_CALLBACK 0x40000000
615static struct rpc_program cb_program = {
616    .name = "nfs4_cb",
617    .number = NFS4_CALLBACK,
618    .nrvers = ARRAY_SIZE(nfs_cb_version),
619    .version = nfs_cb_version,
620    .stats = &cb_stats,
621    .pipe_dir_name = "/nfsd4_cb",
622};
623
624static int max_cb_time(void)
625{
626    return max(nfsd4_lease/10, (time_t)1) * HZ;
627}
628
629
630static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn, struct nfsd4_session *ses)
631{
632    struct rpc_timeout timeparms = {
633        .to_initval = max_cb_time(),
634        .to_retries = 0,
635    };
636    struct rpc_create_args args = {
637        .net = &init_net,
638        .address = (struct sockaddr *) &conn->cb_addr,
639        .addrsize = conn->cb_addrlen,
640        .saddress = (struct sockaddr *) &conn->cb_saddr,
641        .timeout = &timeparms,
642        .program = &cb_program,
643        .version = 0,
644        .authflavor = clp->cl_flavor,
645        .flags = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
646    };
647    struct rpc_clnt *client;
648
649    if (clp->cl_minorversion == 0) {
650        if (!clp->cl_principal && (clp->cl_flavor >= RPC_AUTH_GSS_KRB5))
651            return -EINVAL;
652        args.client_name = clp->cl_principal;
653        args.prognumber = conn->cb_prog,
654        args.protocol = XPRT_TRANSPORT_TCP;
655        clp->cl_cb_ident = conn->cb_ident;
656    } else {
657        if (!conn->cb_xprt)
658            return -EINVAL;
659        clp->cl_cb_conn.cb_xprt = conn->cb_xprt;
660        clp->cl_cb_session = ses;
661        args.bc_xprt = conn->cb_xprt;
662        args.prognumber = clp->cl_cb_session->se_cb_prog;
663        args.protocol = XPRT_TRANSPORT_BC_TCP;
664    }
665    /* Create RPC client */
666    client = rpc_create(&args);
667    if (IS_ERR(client)) {
668        dprintk("NFSD: couldn't create callback client: %ld\n",
669            PTR_ERR(client));
670        return PTR_ERR(client);
671    }
672    clp->cl_cb_client = client;
673    return 0;
674
675}
676
677static void warn_no_callback_path(struct nfs4_client *clp, int reason)
678{
679    dprintk("NFSD: warning: no callback path to client %.*s: error %d\n",
680        (int)clp->cl_name.len, clp->cl_name.data, reason);
681}
682
683static void nfsd4_mark_cb_down(struct nfs4_client *clp, int reason)
684{
685    clp->cl_cb_state = NFSD4_CB_DOWN;
686    warn_no_callback_path(clp, reason);
687}
688
689static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
690{
691    struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
692
693    if (task->tk_status)
694        nfsd4_mark_cb_down(clp, task->tk_status);
695    else
696        clp->cl_cb_state = NFSD4_CB_UP;
697}
698
699static const struct rpc_call_ops nfsd4_cb_probe_ops = {
700    /* XXX: release method to ensure we set the cb channel down if
701     * necessary on early failure? */
702    .rpc_call_done = nfsd4_cb_probe_done,
703};
704
705static struct rpc_cred *callback_cred;
706
707int set_callback_cred(void)
708{
709    if (callback_cred)
710        return 0;
711    callback_cred = rpc_lookup_machine_cred();
712    if (!callback_cred)
713        return -ENOMEM;
714    return 0;
715}
716
717static struct workqueue_struct *callback_wq;
718
719static void run_nfsd4_cb(struct nfsd4_callback *cb)
720{
721    queue_work(callback_wq, &cb->cb_work);
722}
723
724static void do_probe_callback(struct nfs4_client *clp)
725{
726    struct nfsd4_callback *cb = &clp->cl_cb_null;
727
728    cb->cb_op = NULL;
729    cb->cb_clp = clp;
730
731    cb->cb_msg.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_NULL];
732    cb->cb_msg.rpc_argp = NULL;
733    cb->cb_msg.rpc_resp = NULL;
734    cb->cb_msg.rpc_cred = callback_cred;
735
736    cb->cb_ops = &nfsd4_cb_probe_ops;
737
738    run_nfsd4_cb(cb);
739}
740
741/*
742 * Poke the callback thread to process any updates to the callback
743 * parameters, and send a null probe.
744 */
745void nfsd4_probe_callback(struct nfs4_client *clp)
746{
747    /* XXX: atomicity? Also, should we be using cl_cb_flags? */
748    clp->cl_cb_state = NFSD4_CB_UNKNOWN;
749    set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_cb_flags);
750    do_probe_callback(clp);
751}
752
753void nfsd4_probe_callback_sync(struct nfs4_client *clp)
754{
755    nfsd4_probe_callback(clp);
756    flush_workqueue(callback_wq);
757}
758
759void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *conn)
760{
761    clp->cl_cb_state = NFSD4_CB_UNKNOWN;
762    spin_lock(&clp->cl_lock);
763    memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn));
764    spin_unlock(&clp->cl_lock);
765}
766
767/*
768 * There's currently a single callback channel slot.
769 * If the slot is available, then mark it busy. Otherwise, set the
770 * thread for sleeping on the callback RPC wait queue.
771 */
772static bool nfsd41_cb_get_slot(struct nfs4_client *clp, struct rpc_task *task)
773{
774    if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
775        rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
776        dprintk("%s slot is busy\n", __func__);
777        return false;
778    }
779    return true;
780}
781
782/*
783 * TODO: cb_sequence should support referring call lists, cachethis, multiple
784 * slots, and mark callback channel down on communication errors.
785 */
786static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
787{
788    struct nfsd4_callback *cb = calldata;
789    struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
790    struct nfs4_client *clp = dp->dl_client;
791    u32 minorversion = clp->cl_minorversion;
792
793    cb->cb_minorversion = minorversion;
794    if (minorversion) {
795        if (!nfsd41_cb_get_slot(clp, task))
796            return;
797    }
798    spin_lock(&clp->cl_lock);
799    if (list_empty(&cb->cb_per_client)) {
800        /* This is the first call, not a restart */
801        cb->cb_done = false;
802        list_add(&cb->cb_per_client, &clp->cl_callbacks);
803    }
804    spin_unlock(&clp->cl_lock);
805    rpc_call_start(task);
806}
807
808static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
809{
810    struct nfsd4_callback *cb = calldata;
811    struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
812    struct nfs4_client *clp = dp->dl_client;
813
814    dprintk("%s: minorversion=%d\n", __func__,
815        clp->cl_minorversion);
816
817    if (clp->cl_minorversion) {
818        /* No need for lock, access serialized in nfsd4_cb_prepare */
819        ++clp->cl_cb_session->se_cb_seq_nr;
820        clear_bit(0, &clp->cl_cb_slot_busy);
821        rpc_wake_up_next(&clp->cl_cb_waitq);
822        dprintk("%s: freed slot, new seqid=%d\n", __func__,
823            clp->cl_cb_session->se_cb_seq_nr);
824
825        /* We're done looking into the sequence information */
826        task->tk_msg.rpc_resp = NULL;
827    }
828}
829
830
831static void nfsd4_cb_recall_done(struct rpc_task *task, void *calldata)
832{
833    struct nfsd4_callback *cb = calldata;
834    struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
835    struct nfs4_client *clp = dp->dl_client;
836    struct rpc_clnt *current_rpc_client = clp->cl_cb_client;
837
838    nfsd4_cb_done(task, calldata);
839
840    if (current_rpc_client != task->tk_client) {
841        /* We're shutting down or changing cl_cb_client; leave
842         * it to nfsd4_process_cb_update to restart the call if
843         * necessary. */
844        return;
845    }
846
847    if (cb->cb_done)
848        return;
849    switch (task->tk_status) {
850    case 0:
851        cb->cb_done = true;
852        return;
853    case -EBADHANDLE:
854    case -NFS4ERR_BAD_STATEID:
855        /* Race: client probably got cb_recall
856         * before open reply granting delegation */
857        break;
858    default:
859        /* Network partition? */
860        nfsd4_mark_cb_down(clp, task->tk_status);
861    }
862    if (dp->dl_retries--) {
863        rpc_delay(task, 2*HZ);
864        task->tk_status = 0;
865        rpc_restart_call_prepare(task);
866        return;
867    }
868    nfsd4_mark_cb_down(clp, task->tk_status);
869    cb->cb_done = true;
870}
871
872static void nfsd4_cb_recall_release(void *calldata)
873{
874    struct nfsd4_callback *cb = calldata;
875    struct nfs4_client *clp = cb->cb_clp;
876    struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
877
878    if (cb->cb_done) {
879        spin_lock(&clp->cl_lock);
880        list_del(&cb->cb_per_client);
881        spin_unlock(&clp->cl_lock);
882        nfs4_put_delegation(dp);
883    }
884}
885
886static const struct rpc_call_ops nfsd4_cb_recall_ops = {
887    .rpc_call_prepare = nfsd4_cb_prepare,
888    .rpc_call_done = nfsd4_cb_recall_done,
889    .rpc_release = nfsd4_cb_recall_release,
890};
891
892int nfsd4_create_callback_queue(void)
893{
894    callback_wq = create_singlethread_workqueue("nfsd4_callbacks");
895    if (!callback_wq)
896        return -ENOMEM;
897    return 0;
898}
899
900void nfsd4_destroy_callback_queue(void)
901{
902    destroy_workqueue(callback_wq);
903}
904
905/* must be called under the state lock */
906void nfsd4_shutdown_callback(struct nfs4_client *clp)
907{
908    set_bit(NFSD4_CLIENT_KILL, &clp->cl_cb_flags);
909    /*
910     * Note this won't actually result in a null callback;
911     * instead, nfsd4_do_callback_rpc() will detect the killed
912     * client, destroy the rpc client, and stop:
913     */
914    do_probe_callback(clp);
915    flush_workqueue(callback_wq);
916}
917
918static void nfsd4_release_cb(struct nfsd4_callback *cb)
919{
920    if (cb->cb_ops->rpc_release)
921        cb->cb_ops->rpc_release(cb);
922}
923
924/* requires cl_lock: */
925static struct nfsd4_conn * __nfsd4_find_backchannel(struct nfs4_client *clp)
926{
927    struct nfsd4_session *s;
928    struct nfsd4_conn *c;
929
930    list_for_each_entry(s, &clp->cl_sessions, se_perclnt) {
931        list_for_each_entry(c, &s->se_conns, cn_persession) {
932            if (c->cn_flags & NFS4_CDFC4_BACK)
933                return c;
934        }
935    }
936    return NULL;
937}
938
939static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
940{
941    struct nfs4_cb_conn conn;
942    struct nfs4_client *clp = cb->cb_clp;
943    struct nfsd4_session *ses = NULL;
944    struct nfsd4_conn *c;
945    int err;
946
947    /*
948     * This is either an update, or the client dying; in either case,
949     * kill the old client:
950     */
951    if (clp->cl_cb_client) {
952        rpc_shutdown_client(clp->cl_cb_client);
953        clp->cl_cb_client = NULL;
954    }
955    if (clp->cl_cb_conn.cb_xprt) {
956        svc_xprt_put(clp->cl_cb_conn.cb_xprt);
957        clp->cl_cb_conn.cb_xprt = NULL;
958    }
959    if (test_bit(NFSD4_CLIENT_KILL, &clp->cl_cb_flags))
960        return;
961    spin_lock(&clp->cl_lock);
962    /*
963     * Only serialized callback code is allowed to clear these
964     * flags; main nfsd code can only set them:
965     */
966    BUG_ON(!clp->cl_cb_flags);
967    clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_cb_flags);
968    memcpy(&conn, &cb->cb_clp->cl_cb_conn, sizeof(struct nfs4_cb_conn));
969    c = __nfsd4_find_backchannel(clp);
970    if (c) {
971        svc_xprt_get(c->cn_xprt);
972        conn.cb_xprt = c->cn_xprt;
973        ses = c->cn_session;
974    }
975    spin_unlock(&clp->cl_lock);
976
977    err = setup_callback_client(clp, &conn, ses);
978    if (err) {
979        warn_no_callback_path(clp, err);
980        return;
981    }
982    /* Yay, the callback channel's back! Restart any callbacks: */
983    list_for_each_entry(cb, &clp->cl_callbacks, cb_per_client)
984        run_nfsd4_cb(cb);
985}
986
987void nfsd4_do_callback_rpc(struct work_struct *w)
988{
989    struct nfsd4_callback *cb = container_of(w, struct nfsd4_callback, cb_work);
990    struct nfs4_client *clp = cb->cb_clp;
991    struct rpc_clnt *clnt;
992
993    if (clp->cl_cb_flags)
994        nfsd4_process_cb_update(cb);
995
996    clnt = clp->cl_cb_client;
997    if (!clnt) {
998        /* Callback channel broken, or client killed; give up: */
999        nfsd4_release_cb(cb);
1000        return;
1001    }
1002    rpc_call_async(clnt, &cb->cb_msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN,
1003            cb->cb_ops, cb);
1004}
1005
1006void nfsd4_cb_recall(struct nfs4_delegation *dp)
1007{
1008    struct nfsd4_callback *cb = &dp->dl_recall;
1009    struct nfs4_client *clp = dp->dl_client;
1010
1011    dp->dl_retries = 1;
1012    cb->cb_op = dp;
1013    cb->cb_clp = clp;
1014    cb->cb_msg.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_RECALL];
1015    cb->cb_msg.rpc_argp = cb;
1016    cb->cb_msg.rpc_resp = cb;
1017    cb->cb_msg.rpc_cred = callback_cred;
1018
1019    cb->cb_ops = &nfsd4_cb_recall_ops;
1020    dp->dl_retries = 1;
1021
1022    INIT_LIST_HEAD(&cb->cb_per_client);
1023    cb->cb_done = true;
1024
1025    run_nfsd4_cb(&dp->dl_recall);
1026}
1027

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