Merge tag 'jfs-3.10' of git://github.com/kleikamp/linux-shaggy
[linux-3.10.git] / 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 #include "netns.h"
40
41 #define NFSDDBG_FACILITY                NFSDDBG_PROC
42
43 static void nfsd4_mark_cb_fault(struct nfs4_client *, int reason);
44
45 #define NFSPROC4_CB_NULL 0
46 #define NFSPROC4_CB_COMPOUND 1
47
48 /* Index of predefined Linux callback client operations */
49
50 enum {
51         NFSPROC4_CLNT_CB_NULL = 0,
52         NFSPROC4_CLNT_CB_RECALL,
53         NFSPROC4_CLNT_CB_SEQUENCE,
54 };
55
56 #define NFS4_MAXTAGLEN          20
57
58 #define NFS4_enc_cb_null_sz             0
59 #define NFS4_dec_cb_null_sz             0
60 #define cb_compound_enc_hdr_sz          4
61 #define cb_compound_dec_hdr_sz          (3 + (NFS4_MAXTAGLEN >> 2))
62 #define sessionid_sz                    (NFS4_MAX_SESSIONID_LEN >> 2)
63 #define cb_sequence_enc_sz              (sessionid_sz + 4 +             \
64                                         1 /* no referring calls list yet */)
65 #define cb_sequence_dec_sz              (op_dec_sz + sessionid_sz + 4)
66
67 #define op_enc_sz                       1
68 #define op_dec_sz                       2
69 #define enc_nfs4_fh_sz                  (1 + (NFS4_FHSIZE >> 2))
70 #define enc_stateid_sz                  (NFS4_STATEID_SIZE >> 2)
71 #define NFS4_enc_cb_recall_sz           (cb_compound_enc_hdr_sz +       \
72                                         cb_sequence_enc_sz +            \
73                                         1 + enc_stateid_sz +            \
74                                         enc_nfs4_fh_sz)
75
76 #define NFS4_dec_cb_recall_sz           (cb_compound_dec_hdr_sz  +      \
77                                         cb_sequence_dec_sz +            \
78                                         op_dec_sz)
79
80 struct nfs4_cb_compound_hdr {
81         /* args */
82         u32             ident;  /* minorversion 0 only */
83         u32             nops;
84         __be32          *nops_p;
85         u32             minorversion;
86         /* res */
87         int             status;
88 };
89
90 /*
91  * Handle decode buffer overflows out-of-line.
92  */
93 static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
94 {
95         dprintk("NFS: %s prematurely hit the end of our receive buffer. "
96                 "Remaining buffer length is %tu words.\n",
97                 func, xdr->end - xdr->p);
98 }
99
100 static __be32 *xdr_encode_empty_array(__be32 *p)
101 {
102         *p++ = xdr_zero;
103         return p;
104 }
105
106 /*
107  * Encode/decode NFSv4 CB basic data types
108  *
109  * Basic NFSv4 callback data types are defined in section 15 of RFC
110  * 3530: "Network File System (NFS) version 4 Protocol" and section
111  * 20 of RFC 5661: "Network File System (NFS) Version 4 Minor Version
112  * 1 Protocol"
113  */
114
115 /*
116  *      nfs_cb_opnum4
117  *
118  *      enum nfs_cb_opnum4 {
119  *              OP_CB_GETATTR           = 3,
120  *                ...
121  *      };
122  */
123 enum nfs_cb_opnum4 {
124         OP_CB_GETATTR                   = 3,
125         OP_CB_RECALL                    = 4,
126         OP_CB_LAYOUTRECALL              = 5,
127         OP_CB_NOTIFY                    = 6,
128         OP_CB_PUSH_DELEG                = 7,
129         OP_CB_RECALL_ANY                = 8,
130         OP_CB_RECALLABLE_OBJ_AVAIL      = 9,
131         OP_CB_RECALL_SLOT               = 10,
132         OP_CB_SEQUENCE                  = 11,
133         OP_CB_WANTS_CANCELLED           = 12,
134         OP_CB_NOTIFY_LOCK               = 13,
135         OP_CB_NOTIFY_DEVICEID           = 14,
136         OP_CB_ILLEGAL                   = 10044
137 };
138
139 static void encode_nfs_cb_opnum4(struct xdr_stream *xdr, enum nfs_cb_opnum4 op)
140 {
141         __be32 *p;
142
143         p = xdr_reserve_space(xdr, 4);
144         *p = cpu_to_be32(op);
145 }
146
147 /*
148  * nfs_fh4
149  *
150  *      typedef opaque nfs_fh4<NFS4_FHSIZE>;
151  */
152 static void encode_nfs_fh4(struct xdr_stream *xdr, const struct knfsd_fh *fh)
153 {
154         u32 length = fh->fh_size;
155         __be32 *p;
156
157         BUG_ON(length > NFS4_FHSIZE);
158         p = xdr_reserve_space(xdr, 4 + length);
159         xdr_encode_opaque(p, &fh->fh_base, length);
160 }
161
162 /*
163  * stateid4
164  *
165  *      struct stateid4 {
166  *              uint32_t        seqid;
167  *              opaque          other[12];
168  *      };
169  */
170 static void encode_stateid4(struct xdr_stream *xdr, const stateid_t *sid)
171 {
172         __be32 *p;
173
174         p = xdr_reserve_space(xdr, NFS4_STATEID_SIZE);
175         *p++ = cpu_to_be32(sid->si_generation);
176         xdr_encode_opaque_fixed(p, &sid->si_opaque, NFS4_STATEID_OTHER_SIZE);
177 }
178
179 /*
180  * sessionid4
181  *
182  *      typedef opaque sessionid4[NFS4_SESSIONID_SIZE];
183  */
184 static void encode_sessionid4(struct xdr_stream *xdr,
185                               const struct nfsd4_session *session)
186 {
187         __be32 *p;
188
189         p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN);
190         xdr_encode_opaque_fixed(p, session->se_sessionid.data,
191                                         NFS4_MAX_SESSIONID_LEN);
192 }
193
194 /*
195  * nfsstat4
196  */
197 static const struct {
198         int stat;
199         int errno;
200 } nfs_cb_errtbl[] = {
201         { NFS4_OK,              0               },
202         { NFS4ERR_PERM,         -EPERM          },
203         { NFS4ERR_NOENT,        -ENOENT         },
204         { NFS4ERR_IO,           -EIO            },
205         { NFS4ERR_NXIO,         -ENXIO          },
206         { NFS4ERR_ACCESS,       -EACCES         },
207         { NFS4ERR_EXIST,        -EEXIST         },
208         { NFS4ERR_XDEV,         -EXDEV          },
209         { NFS4ERR_NOTDIR,       -ENOTDIR        },
210         { NFS4ERR_ISDIR,        -EISDIR         },
211         { NFS4ERR_INVAL,        -EINVAL         },
212         { NFS4ERR_FBIG,         -EFBIG          },
213         { NFS4ERR_NOSPC,        -ENOSPC         },
214         { NFS4ERR_ROFS,         -EROFS          },
215         { NFS4ERR_MLINK,        -EMLINK         },
216         { NFS4ERR_NAMETOOLONG,  -ENAMETOOLONG   },
217         { NFS4ERR_NOTEMPTY,     -ENOTEMPTY      },
218         { NFS4ERR_DQUOT,        -EDQUOT         },
219         { NFS4ERR_STALE,        -ESTALE         },
220         { NFS4ERR_BADHANDLE,    -EBADHANDLE     },
221         { NFS4ERR_BAD_COOKIE,   -EBADCOOKIE     },
222         { NFS4ERR_NOTSUPP,      -ENOTSUPP       },
223         { NFS4ERR_TOOSMALL,     -ETOOSMALL      },
224         { NFS4ERR_SERVERFAULT,  -ESERVERFAULT   },
225         { NFS4ERR_BADTYPE,      -EBADTYPE       },
226         { NFS4ERR_LOCKED,       -EAGAIN         },
227         { NFS4ERR_RESOURCE,     -EREMOTEIO      },
228         { NFS4ERR_SYMLINK,      -ELOOP          },
229         { NFS4ERR_OP_ILLEGAL,   -EOPNOTSUPP     },
230         { NFS4ERR_DEADLOCK,     -EDEADLK        },
231         { -1,                   -EIO            }
232 };
233
234 /*
235  * If we cannot translate the error, the recovery routines should
236  * handle it.
237  *
238  * Note: remaining NFSv4 error codes have values > 10000, so should
239  * not conflict with native Linux error codes.
240  */
241 static int nfs_cb_stat_to_errno(int status)
242 {
243         int i;
244
245         for (i = 0; nfs_cb_errtbl[i].stat != -1; i++) {
246                 if (nfs_cb_errtbl[i].stat == status)
247                         return nfs_cb_errtbl[i].errno;
248         }
249
250         dprintk("NFSD: Unrecognized NFS CB status value: %u\n", status);
251         return -status;
252 }
253
254 static int decode_cb_op_status(struct xdr_stream *xdr, enum nfs_opnum4 expected,
255                                enum nfsstat4 *status)
256 {
257         __be32 *p;
258         u32 op;
259
260         p = xdr_inline_decode(xdr, 4 + 4);
261         if (unlikely(p == NULL))
262                 goto out_overflow;
263         op = be32_to_cpup(p++);
264         if (unlikely(op != expected))
265                 goto out_unexpected;
266         *status = be32_to_cpup(p);
267         return 0;
268 out_overflow:
269         print_overflow_msg(__func__, xdr);
270         return -EIO;
271 out_unexpected:
272         dprintk("NFSD: Callback server returned operation %d but "
273                 "we issued a request for %d\n", op, expected);
274         return -EIO;
275 }
276
277 /*
278  * CB_COMPOUND4args
279  *
280  *      struct CB_COMPOUND4args {
281  *              utf8str_cs      tag;
282  *              uint32_t        minorversion;
283  *              uint32_t        callback_ident;
284  *              nfs_cb_argop4   argarray<>;
285  *      };
286 */
287 static void encode_cb_compound4args(struct xdr_stream *xdr,
288                                     struct nfs4_cb_compound_hdr *hdr)
289 {
290         __be32 * p;
291
292         p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4);
293         p = xdr_encode_empty_array(p);          /* empty tag */
294         *p++ = cpu_to_be32(hdr->minorversion);
295         *p++ = cpu_to_be32(hdr->ident);
296
297         hdr->nops_p = p;
298         *p = cpu_to_be32(hdr->nops);            /* argarray element count */
299 }
300
301 /*
302  * Update argarray element count
303  */
304 static void encode_cb_nops(struct nfs4_cb_compound_hdr *hdr)
305 {
306         BUG_ON(hdr->nops > NFS4_MAX_BACK_CHANNEL_OPS);
307         *hdr->nops_p = cpu_to_be32(hdr->nops);
308 }
309
310 /*
311  * CB_COMPOUND4res
312  *
313  *      struct CB_COMPOUND4res {
314  *              nfsstat4        status;
315  *              utf8str_cs      tag;
316  *              nfs_cb_resop4   resarray<>;
317  *      };
318  */
319 static int decode_cb_compound4res(struct xdr_stream *xdr,
320                                   struct nfs4_cb_compound_hdr *hdr)
321 {
322         u32 length;
323         __be32 *p;
324
325         p = xdr_inline_decode(xdr, 4 + 4);
326         if (unlikely(p == NULL))
327                 goto out_overflow;
328         hdr->status = be32_to_cpup(p++);
329         /* Ignore the tag */
330         length = be32_to_cpup(p++);
331         p = xdr_inline_decode(xdr, length + 4);
332         if (unlikely(p == NULL))
333                 goto out_overflow;
334         hdr->nops = be32_to_cpup(p);
335         return 0;
336 out_overflow:
337         print_overflow_msg(__func__, xdr);
338         return -EIO;
339 }
340
341 /*
342  * CB_RECALL4args
343  *
344  *      struct CB_RECALL4args {
345  *              stateid4        stateid;
346  *              bool            truncate;
347  *              nfs_fh4         fh;
348  *      };
349  */
350 static void encode_cb_recall4args(struct xdr_stream *xdr,
351                                   const struct nfs4_delegation *dp,
352                                   struct nfs4_cb_compound_hdr *hdr)
353 {
354         __be32 *p;
355
356         encode_nfs_cb_opnum4(xdr, OP_CB_RECALL);
357         encode_stateid4(xdr, &dp->dl_stid.sc_stateid);
358
359         p = xdr_reserve_space(xdr, 4);
360         *p++ = xdr_zero;                        /* truncate */
361
362         encode_nfs_fh4(xdr, &dp->dl_fh);
363
364         hdr->nops++;
365 }
366
367 /*
368  * CB_SEQUENCE4args
369  *
370  *      struct CB_SEQUENCE4args {
371  *              sessionid4              csa_sessionid;
372  *              sequenceid4             csa_sequenceid;
373  *              slotid4                 csa_slotid;
374  *              slotid4                 csa_highest_slotid;
375  *              bool                    csa_cachethis;
376  *              referring_call_list4    csa_referring_call_lists<>;
377  *      };
378  */
379 static void encode_cb_sequence4args(struct xdr_stream *xdr,
380                                     const struct nfsd4_callback *cb,
381                                     struct nfs4_cb_compound_hdr *hdr)
382 {
383         struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
384         __be32 *p;
385
386         if (hdr->minorversion == 0)
387                 return;
388
389         encode_nfs_cb_opnum4(xdr, OP_CB_SEQUENCE);
390         encode_sessionid4(xdr, session);
391
392         p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4 + 4);
393         *p++ = cpu_to_be32(session->se_cb_seq_nr);      /* csa_sequenceid */
394         *p++ = xdr_zero;                        /* csa_slotid */
395         *p++ = xdr_zero;                        /* csa_highest_slotid */
396         *p++ = xdr_zero;                        /* csa_cachethis */
397         xdr_encode_empty_array(p);              /* csa_referring_call_lists */
398
399         hdr->nops++;
400 }
401
402 /*
403  * CB_SEQUENCE4resok
404  *
405  *      struct CB_SEQUENCE4resok {
406  *              sessionid4      csr_sessionid;
407  *              sequenceid4     csr_sequenceid;
408  *              slotid4         csr_slotid;
409  *              slotid4         csr_highest_slotid;
410  *              slotid4         csr_target_highest_slotid;
411  *      };
412  *
413  *      union CB_SEQUENCE4res switch (nfsstat4 csr_status) {
414  *      case NFS4_OK:
415  *              CB_SEQUENCE4resok       csr_resok4;
416  *      default:
417  *              void;
418  *      };
419  *
420  * Our current back channel implmentation supports a single backchannel
421  * with a single slot.
422  */
423 static int decode_cb_sequence4resok(struct xdr_stream *xdr,
424                                     struct nfsd4_callback *cb)
425 {
426         struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
427         struct nfs4_sessionid id;
428         int status;
429         __be32 *p;
430         u32 dummy;
431
432         status = -ESERVERFAULT;
433
434         /*
435          * If the server returns different values for sessionID, slotID or
436          * sequence number, the server is looney tunes.
437          */
438         p = xdr_inline_decode(xdr, NFS4_MAX_SESSIONID_LEN + 4 + 4 + 4 + 4);
439         if (unlikely(p == NULL))
440                 goto out_overflow;
441         memcpy(id.data, p, NFS4_MAX_SESSIONID_LEN);
442         if (memcmp(id.data, session->se_sessionid.data,
443                                         NFS4_MAX_SESSIONID_LEN) != 0) {
444                 dprintk("NFS: %s Invalid session id\n", __func__);
445                 goto out;
446         }
447         p += XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN);
448
449         dummy = be32_to_cpup(p++);
450         if (dummy != session->se_cb_seq_nr) {
451                 dprintk("NFS: %s Invalid sequence number\n", __func__);
452                 goto out;
453         }
454
455         dummy = be32_to_cpup(p++);
456         if (dummy != 0) {
457                 dprintk("NFS: %s Invalid slotid\n", __func__);
458                 goto out;
459         }
460
461         /*
462          * FIXME: process highest slotid and target highest slotid
463          */
464         status = 0;
465 out:
466         if (status)
467                 nfsd4_mark_cb_fault(cb->cb_clp, status);
468         return status;
469 out_overflow:
470         print_overflow_msg(__func__, xdr);
471         return -EIO;
472 }
473
474 static int decode_cb_sequence4res(struct xdr_stream *xdr,
475                                   struct nfsd4_callback *cb)
476 {
477         enum nfsstat4 nfserr;
478         int status;
479
480         if (cb->cb_minorversion == 0)
481                 return 0;
482
483         status = decode_cb_op_status(xdr, OP_CB_SEQUENCE, &nfserr);
484         if (unlikely(status))
485                 goto out;
486         if (unlikely(nfserr != NFS4_OK))
487                 goto out_default;
488         status = decode_cb_sequence4resok(xdr, cb);
489 out:
490         return status;
491 out_default:
492         return nfs_cb_stat_to_errno(nfserr);
493 }
494
495 /*
496  * NFSv4.0 and NFSv4.1 XDR encode functions
497  *
498  * NFSv4.0 callback argument types are defined in section 15 of RFC
499  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
500  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
501  * Protocol".
502  */
503
504 /*
505  * NB: Without this zero space reservation, callbacks over krb5p fail
506  */
507 static void nfs4_xdr_enc_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
508                                  void *__unused)
509 {
510         xdr_reserve_space(xdr, 0);
511 }
512
513 /*
514  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
515  */
516 static void nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, struct xdr_stream *xdr,
517                                    const struct nfsd4_callback *cb)
518 {
519         const struct nfs4_delegation *args = cb->cb_op;
520         struct nfs4_cb_compound_hdr hdr = {
521                 .ident = cb->cb_clp->cl_cb_ident,
522                 .minorversion = cb->cb_minorversion,
523         };
524
525         encode_cb_compound4args(xdr, &hdr);
526         encode_cb_sequence4args(xdr, cb, &hdr);
527         encode_cb_recall4args(xdr, args, &hdr);
528         encode_cb_nops(&hdr);
529 }
530
531
532 /*
533  * NFSv4.0 and NFSv4.1 XDR decode functions
534  *
535  * NFSv4.0 callback result types are defined in section 15 of RFC
536  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
537  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
538  * Protocol".
539  */
540
541 static int nfs4_xdr_dec_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
542                                 void *__unused)
543 {
544         return 0;
545 }
546
547 /*
548  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
549  */
550 static int nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp,
551                                   struct xdr_stream *xdr,
552                                   struct nfsd4_callback *cb)
553 {
554         struct nfs4_cb_compound_hdr hdr;
555         enum nfsstat4 nfserr;
556         int status;
557
558         status = decode_cb_compound4res(xdr, &hdr);
559         if (unlikely(status))
560                 goto out;
561
562         if (cb != NULL) {
563                 status = decode_cb_sequence4res(xdr, cb);
564                 if (unlikely(status))
565                         goto out;
566         }
567
568         status = decode_cb_op_status(xdr, OP_CB_RECALL, &nfserr);
569         if (unlikely(status))
570                 goto out;
571         if (unlikely(nfserr != NFS4_OK))
572                 status = nfs_cb_stat_to_errno(nfserr);
573 out:
574         return status;
575 }
576
577 /*
578  * RPC procedure tables
579  */
580 #define PROC(proc, call, argtype, restype)                              \
581 [NFSPROC4_CLNT_##proc] = {                                              \
582         .p_proc    = NFSPROC4_CB_##call,                                \
583         .p_encode  = (kxdreproc_t)nfs4_xdr_enc_##argtype,               \
584         .p_decode  = (kxdrdproc_t)nfs4_xdr_dec_##restype,               \
585         .p_arglen  = NFS4_enc_##argtype##_sz,                           \
586         .p_replen  = NFS4_dec_##restype##_sz,                           \
587         .p_statidx = NFSPROC4_CB_##call,                                \
588         .p_name    = #proc,                                             \
589 }
590
591 static struct rpc_procinfo nfs4_cb_procedures[] = {
592         PROC(CB_NULL,   NULL,           cb_null,        cb_null),
593         PROC(CB_RECALL, COMPOUND,       cb_recall,      cb_recall),
594 };
595
596 static struct rpc_version nfs_cb_version4 = {
597 /*
598  * Note on the callback rpc program version number: despite language in rfc
599  * 5661 section 18.36.3 requiring servers to use 4 in this field, the
600  * official xdr descriptions for both 4.0 and 4.1 specify version 1, and
601  * in practice that appears to be what implementations use.  The section
602  * 18.36.3 language is expected to be fixed in an erratum.
603  */
604         .number                 = 1,
605         .nrprocs                = ARRAY_SIZE(nfs4_cb_procedures),
606         .procs                  = nfs4_cb_procedures
607 };
608
609 static const struct rpc_version *nfs_cb_version[] = {
610         &nfs_cb_version4,
611 };
612
613 static const struct rpc_program cb_program;
614
615 static struct rpc_stat cb_stats = {
616         .program                = &cb_program
617 };
618
619 #define NFS4_CALLBACK 0x40000000
620 static const struct rpc_program cb_program = {
621         .name                   = "nfs4_cb",
622         .number                 = NFS4_CALLBACK,
623         .nrvers                 = ARRAY_SIZE(nfs_cb_version),
624         .version                = nfs_cb_version,
625         .stats                  = &cb_stats,
626         .pipe_dir_name          = "nfsd4_cb",
627 };
628
629 static int max_cb_time(struct net *net)
630 {
631         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
632         return max(nn->nfsd4_lease/10, (time_t)1) * HZ;
633 }
634
635 static struct rpc_cred *callback_cred;
636
637 int set_callback_cred(void)
638 {
639         if (callback_cred)
640                 return 0;
641         callback_cred = rpc_lookup_machine_cred("nfs");
642         if (!callback_cred)
643                 return -ENOMEM;
644         return 0;
645 }
646
647 static struct rpc_cred *get_backchannel_cred(struct nfs4_client *clp, struct rpc_clnt *client, struct nfsd4_session *ses)
648 {
649         if (clp->cl_minorversion == 0) {
650                 return get_rpccred(callback_cred);
651         } else {
652                 struct rpc_auth *auth = client->cl_auth;
653                 struct auth_cred acred = {};
654
655                 acred.uid = ses->se_cb_sec.uid;
656                 acred.gid = ses->se_cb_sec.gid;
657                 return auth->au_ops->lookup_cred(client->cl_auth, &acred, 0);
658         }
659 }
660
661 static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn, struct nfsd4_session *ses)
662 {
663         struct rpc_timeout      timeparms = {
664                 .to_initval     = max_cb_time(clp->net),
665                 .to_retries     = 0,
666         };
667         struct rpc_create_args args = {
668                 .net            = clp->net,
669                 .address        = (struct sockaddr *) &conn->cb_addr,
670                 .addrsize       = conn->cb_addrlen,
671                 .saddress       = (struct sockaddr *) &conn->cb_saddr,
672                 .timeout        = &timeparms,
673                 .program        = &cb_program,
674                 .version        = 0,
675                 .flags          = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
676         };
677         struct rpc_clnt *client;
678         struct rpc_cred *cred;
679
680         if (clp->cl_minorversion == 0) {
681                 if (!clp->cl_cred.cr_principal &&
682                                 (clp->cl_cred.cr_flavor >= RPC_AUTH_GSS_KRB5))
683                         return -EINVAL;
684                 args.client_name = clp->cl_cred.cr_principal;
685                 args.prognumber = conn->cb_prog,
686                 args.protocol = XPRT_TRANSPORT_TCP;
687                 args.authflavor = clp->cl_cred.cr_flavor;
688                 clp->cl_cb_ident = conn->cb_ident;
689         } else {
690                 if (!conn->cb_xprt)
691                         return -EINVAL;
692                 clp->cl_cb_conn.cb_xprt = conn->cb_xprt;
693                 clp->cl_cb_session = ses;
694                 args.bc_xprt = conn->cb_xprt;
695                 args.prognumber = clp->cl_cb_session->se_cb_prog;
696                 args.protocol = XPRT_TRANSPORT_BC_TCP;
697                 args.authflavor = ses->se_cb_sec.flavor;
698         }
699         /* Create RPC client */
700         client = rpc_create(&args);
701         if (IS_ERR(client)) {
702                 dprintk("NFSD: couldn't create callback client: %ld\n",
703                         PTR_ERR(client));
704                 return PTR_ERR(client);
705         }
706         cred = get_backchannel_cred(clp, client, ses);
707         if (IS_ERR(cred)) {
708                 rpc_shutdown_client(client);
709                 return PTR_ERR(cred);
710         }
711         clp->cl_cb_client = client;
712         clp->cl_cb_cred = cred;
713         return 0;
714 }
715
716 static void warn_no_callback_path(struct nfs4_client *clp, int reason)
717 {
718         dprintk("NFSD: warning: no callback path to client %.*s: error %d\n",
719                 (int)clp->cl_name.len, clp->cl_name.data, reason);
720 }
721
722 static void nfsd4_mark_cb_down(struct nfs4_client *clp, int reason)
723 {
724         clp->cl_cb_state = NFSD4_CB_DOWN;
725         warn_no_callback_path(clp, reason);
726 }
727
728 static void nfsd4_mark_cb_fault(struct nfs4_client *clp, int reason)
729 {
730         clp->cl_cb_state = NFSD4_CB_FAULT;
731         warn_no_callback_path(clp, reason);
732 }
733
734 static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
735 {
736         struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
737
738         if (task->tk_status)
739                 nfsd4_mark_cb_down(clp, task->tk_status);
740         else
741                 clp->cl_cb_state = NFSD4_CB_UP;
742 }
743
744 static const struct rpc_call_ops nfsd4_cb_probe_ops = {
745         /* XXX: release method to ensure we set the cb channel down if
746          * necessary on early failure? */
747         .rpc_call_done = nfsd4_cb_probe_done,
748 };
749
750 static struct workqueue_struct *callback_wq;
751
752 static void run_nfsd4_cb(struct nfsd4_callback *cb)
753 {
754         queue_work(callback_wq, &cb->cb_work);
755 }
756
757 static void do_probe_callback(struct nfs4_client *clp)
758 {
759         struct nfsd4_callback *cb = &clp->cl_cb_null;
760
761         cb->cb_op = NULL;
762         cb->cb_clp = clp;
763
764         cb->cb_msg.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_NULL];
765         cb->cb_msg.rpc_argp = NULL;
766         cb->cb_msg.rpc_resp = NULL;
767
768         cb->cb_ops = &nfsd4_cb_probe_ops;
769
770         run_nfsd4_cb(cb);
771 }
772
773 /*
774  * Poke the callback thread to process any updates to the callback
775  * parameters, and send a null probe.
776  */
777 void nfsd4_probe_callback(struct nfs4_client *clp)
778 {
779         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
780         set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
781         do_probe_callback(clp);
782 }
783
784 void nfsd4_probe_callback_sync(struct nfs4_client *clp)
785 {
786         nfsd4_probe_callback(clp);
787         flush_workqueue(callback_wq);
788 }
789
790 void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *conn)
791 {
792         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
793         spin_lock(&clp->cl_lock);
794         memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn));
795         spin_unlock(&clp->cl_lock);
796 }
797
798 /*
799  * There's currently a single callback channel slot.
800  * If the slot is available, then mark it busy.  Otherwise, set the
801  * thread for sleeping on the callback RPC wait queue.
802  */
803 static bool nfsd41_cb_get_slot(struct nfs4_client *clp, struct rpc_task *task)
804 {
805         if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
806                 rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
807                 dprintk("%s slot is busy\n", __func__);
808                 return false;
809         }
810         return true;
811 }
812
813 /*
814  * TODO: cb_sequence should support referring call lists, cachethis, multiple
815  * slots, and mark callback channel down on communication errors.
816  */
817 static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
818 {
819         struct nfsd4_callback *cb = calldata;
820         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
821         struct nfs4_client *clp = dp->dl_stid.sc_client;
822         u32 minorversion = clp->cl_minorversion;
823
824         cb->cb_minorversion = minorversion;
825         if (minorversion) {
826                 if (!nfsd41_cb_get_slot(clp, task))
827                         return;
828         }
829         spin_lock(&clp->cl_lock);
830         if (list_empty(&cb->cb_per_client)) {
831                 /* This is the first call, not a restart */
832                 cb->cb_done = false;
833                 list_add(&cb->cb_per_client, &clp->cl_callbacks);
834         }
835         spin_unlock(&clp->cl_lock);
836         rpc_call_start(task);
837 }
838
839 static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
840 {
841         struct nfsd4_callback *cb = calldata;
842         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
843         struct nfs4_client *clp = dp->dl_stid.sc_client;
844
845         dprintk("%s: minorversion=%d\n", __func__,
846                 clp->cl_minorversion);
847
848         if (clp->cl_minorversion) {
849                 /* No need for lock, access serialized in nfsd4_cb_prepare */
850                 ++clp->cl_cb_session->se_cb_seq_nr;
851                 clear_bit(0, &clp->cl_cb_slot_busy);
852                 rpc_wake_up_next(&clp->cl_cb_waitq);
853                 dprintk("%s: freed slot, new seqid=%d\n", __func__,
854                         clp->cl_cb_session->se_cb_seq_nr);
855
856                 /* We're done looking into the sequence information */
857                 task->tk_msg.rpc_resp = NULL;
858         }
859 }
860
861
862 static void nfsd4_cb_recall_done(struct rpc_task *task, void *calldata)
863 {
864         struct nfsd4_callback *cb = calldata;
865         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
866         struct nfs4_client *clp = dp->dl_stid.sc_client;
867         struct rpc_clnt *current_rpc_client = clp->cl_cb_client;
868
869         nfsd4_cb_done(task, calldata);
870
871         if (current_rpc_client != task->tk_client) {
872                 /* We're shutting down or changing cl_cb_client; leave
873                  * it to nfsd4_process_cb_update to restart the call if
874                  * necessary. */
875                 return;
876         }
877
878         if (cb->cb_done)
879                 return;
880         switch (task->tk_status) {
881         case 0:
882                 cb->cb_done = true;
883                 return;
884         case -EBADHANDLE:
885         case -NFS4ERR_BAD_STATEID:
886                 /* Race: client probably got cb_recall
887                  * before open reply granting delegation */
888                 break;
889         default:
890                 /* Network partition? */
891                 nfsd4_mark_cb_down(clp, task->tk_status);
892         }
893         if (dp->dl_retries--) {
894                 rpc_delay(task, 2*HZ);
895                 task->tk_status = 0;
896                 rpc_restart_call_prepare(task);
897                 return;
898         }
899         nfsd4_mark_cb_down(clp, task->tk_status);
900         cb->cb_done = true;
901 }
902
903 static void nfsd4_cb_recall_release(void *calldata)
904 {
905         struct nfsd4_callback *cb = calldata;
906         struct nfs4_client *clp = cb->cb_clp;
907         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
908
909         if (cb->cb_done) {
910                 spin_lock(&clp->cl_lock);
911                 list_del(&cb->cb_per_client);
912                 spin_unlock(&clp->cl_lock);
913                 nfs4_put_delegation(dp);
914         }
915 }
916
917 static const struct rpc_call_ops nfsd4_cb_recall_ops = {
918         .rpc_call_prepare = nfsd4_cb_prepare,
919         .rpc_call_done = nfsd4_cb_recall_done,
920         .rpc_release = nfsd4_cb_recall_release,
921 };
922
923 int nfsd4_create_callback_queue(void)
924 {
925         callback_wq = create_singlethread_workqueue("nfsd4_callbacks");
926         if (!callback_wq)
927                 return -ENOMEM;
928         return 0;
929 }
930
931 void nfsd4_destroy_callback_queue(void)
932 {
933         destroy_workqueue(callback_wq);
934 }
935
936 /* must be called under the state lock */
937 void nfsd4_shutdown_callback(struct nfs4_client *clp)
938 {
939         set_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags);
940         /*
941          * Note this won't actually result in a null callback;
942          * instead, nfsd4_do_callback_rpc() will detect the killed
943          * client, destroy the rpc client, and stop:
944          */
945         do_probe_callback(clp);
946         flush_workqueue(callback_wq);
947 }
948
949 static void nfsd4_release_cb(struct nfsd4_callback *cb)
950 {
951         if (cb->cb_ops->rpc_release)
952                 cb->cb_ops->rpc_release(cb);
953 }
954
955 /* requires cl_lock: */
956 static struct nfsd4_conn * __nfsd4_find_backchannel(struct nfs4_client *clp)
957 {
958         struct nfsd4_session *s;
959         struct nfsd4_conn *c;
960
961         list_for_each_entry(s, &clp->cl_sessions, se_perclnt) {
962                 list_for_each_entry(c, &s->se_conns, cn_persession) {
963                         if (c->cn_flags & NFS4_CDFC4_BACK)
964                                 return c;
965                 }
966         }
967         return NULL;
968 }
969
970 static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
971 {
972         struct nfs4_cb_conn conn;
973         struct nfs4_client *clp = cb->cb_clp;
974         struct nfsd4_session *ses = NULL;
975         struct nfsd4_conn *c;
976         int err;
977
978         /*
979          * This is either an update, or the client dying; in either case,
980          * kill the old client:
981          */
982         if (clp->cl_cb_client) {
983                 rpc_shutdown_client(clp->cl_cb_client);
984                 clp->cl_cb_client = NULL;
985                 put_rpccred(clp->cl_cb_cred);
986                 clp->cl_cb_cred = NULL;
987         }
988         if (clp->cl_cb_conn.cb_xprt) {
989                 svc_xprt_put(clp->cl_cb_conn.cb_xprt);
990                 clp->cl_cb_conn.cb_xprt = NULL;
991         }
992         if (test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags))
993                 return;
994         spin_lock(&clp->cl_lock);
995         /*
996          * Only serialized callback code is allowed to clear these
997          * flags; main nfsd code can only set them:
998          */
999         BUG_ON(!(clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK));
1000         clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
1001         memcpy(&conn, &cb->cb_clp->cl_cb_conn, sizeof(struct nfs4_cb_conn));
1002         c = __nfsd4_find_backchannel(clp);
1003         if (c) {
1004                 svc_xprt_get(c->cn_xprt);
1005                 conn.cb_xprt = c->cn_xprt;
1006                 ses = c->cn_session;
1007         }
1008         spin_unlock(&clp->cl_lock);
1009
1010         err = setup_callback_client(clp, &conn, ses);
1011         if (err) {
1012                 nfsd4_mark_cb_down(clp, err);
1013                 return;
1014         }
1015         /* Yay, the callback channel's back! Restart any callbacks: */
1016         list_for_each_entry(cb, &clp->cl_callbacks, cb_per_client)
1017                 run_nfsd4_cb(cb);
1018 }
1019
1020 static void nfsd4_do_callback_rpc(struct work_struct *w)
1021 {
1022         struct nfsd4_callback *cb = container_of(w, struct nfsd4_callback, cb_work);
1023         struct nfs4_client *clp = cb->cb_clp;
1024         struct rpc_clnt *clnt;
1025
1026         if (clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK)
1027                 nfsd4_process_cb_update(cb);
1028
1029         clnt = clp->cl_cb_client;
1030         if (!clnt) {
1031                 /* Callback channel broken, or client killed; give up: */
1032                 nfsd4_release_cb(cb);
1033                 return;
1034         }
1035         cb->cb_msg.rpc_cred = clp->cl_cb_cred;
1036         rpc_call_async(clnt, &cb->cb_msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN,
1037                         cb->cb_ops, cb);
1038 }
1039
1040 void nfsd4_init_callback(struct nfsd4_callback *cb)
1041 {
1042         INIT_WORK(&cb->cb_work, nfsd4_do_callback_rpc);
1043 }
1044
1045 void nfsd4_cb_recall(struct nfs4_delegation *dp)
1046 {
1047         struct nfsd4_callback *cb = &dp->dl_recall;
1048         struct nfs4_client *clp = dp->dl_stid.sc_client;
1049
1050         dp->dl_retries = 1;
1051         cb->cb_op = dp;
1052         cb->cb_clp = clp;
1053         cb->cb_msg.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_RECALL];
1054         cb->cb_msg.rpc_argp = cb;
1055         cb->cb_msg.rpc_resp = cb;
1056
1057         cb->cb_ops = &nfsd4_cb_recall_ops;
1058
1059         INIT_LIST_HEAD(&cb->cb_per_client);
1060         cb->cb_done = true;
1061
1062         run_nfsd4_cb(&dp->dl_recall);
1063 }