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Linux/fs/nfsd/nfs4callback.c

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  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 #include "xdr4cb.h"
 41 
 42 #define NFSDDBG_FACILITY                NFSDDBG_PROC
 43 
 44 static void nfsd4_mark_cb_fault(struct nfs4_client *, int reason);
 45 
 46 #define NFSPROC4_CB_NULL 0
 47 #define NFSPROC4_CB_COMPOUND 1
 48 
 49 /* Index of predefined Linux callback client operations */
 50 
 51 enum {
 52         NFSPROC4_CLNT_CB_NULL = 0,
 53         NFSPROC4_CLNT_CB_RECALL,
 54         NFSPROC4_CLNT_CB_SEQUENCE,
 55 };
 56 
 57 struct nfs4_cb_compound_hdr {
 58         /* args */
 59         u32             ident;  /* minorversion 0 only */
 60         u32             nops;
 61         __be32          *nops_p;
 62         u32             minorversion;
 63         /* res */
 64         int             status;
 65 };
 66 
 67 /*
 68  * Handle decode buffer overflows out-of-line.
 69  */
 70 static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
 71 {
 72         dprintk("NFS: %s prematurely hit the end of our receive buffer. "
 73                 "Remaining buffer length is %tu words.\n",
 74                 func, xdr->end - xdr->p);
 75 }
 76 
 77 static __be32 *xdr_encode_empty_array(__be32 *p)
 78 {
 79         *p++ = xdr_zero;
 80         return p;
 81 }
 82 
 83 /*
 84  * Encode/decode NFSv4 CB basic data types
 85  *
 86  * Basic NFSv4 callback data types are defined in section 15 of RFC
 87  * 3530: "Network File System (NFS) version 4 Protocol" and section
 88  * 20 of RFC 5661: "Network File System (NFS) Version 4 Minor Version
 89  * 1 Protocol"
 90  */
 91 
 92 /*
 93  *      nfs_cb_opnum4
 94  *
 95  *      enum nfs_cb_opnum4 {
 96  *              OP_CB_GETATTR           = 3,
 97  *                ...
 98  *      };
 99  */
100 enum nfs_cb_opnum4 {
101         OP_CB_GETATTR                   = 3,
102         OP_CB_RECALL                    = 4,
103         OP_CB_LAYOUTRECALL              = 5,
104         OP_CB_NOTIFY                    = 6,
105         OP_CB_PUSH_DELEG                = 7,
106         OP_CB_RECALL_ANY                = 8,
107         OP_CB_RECALLABLE_OBJ_AVAIL      = 9,
108         OP_CB_RECALL_SLOT               = 10,
109         OP_CB_SEQUENCE                  = 11,
110         OP_CB_WANTS_CANCELLED           = 12,
111         OP_CB_NOTIFY_LOCK               = 13,
112         OP_CB_NOTIFY_DEVICEID           = 14,
113         OP_CB_ILLEGAL                   = 10044
114 };
115 
116 static void encode_nfs_cb_opnum4(struct xdr_stream *xdr, enum nfs_cb_opnum4 op)
117 {
118         __be32 *p;
119 
120         p = xdr_reserve_space(xdr, 4);
121         *p = cpu_to_be32(op);
122 }
123 
124 /*
125  * nfs_fh4
126  *
127  *      typedef opaque nfs_fh4<NFS4_FHSIZE>;
128  */
129 static void encode_nfs_fh4(struct xdr_stream *xdr, const struct knfsd_fh *fh)
130 {
131         u32 length = fh->fh_size;
132         __be32 *p;
133 
134         BUG_ON(length > NFS4_FHSIZE);
135         p = xdr_reserve_space(xdr, 4 + length);
136         xdr_encode_opaque(p, &fh->fh_base, length);
137 }
138 
139 /*
140  * stateid4
141  *
142  *      struct stateid4 {
143  *              uint32_t        seqid;
144  *              opaque          other[12];
145  *      };
146  */
147 static void encode_stateid4(struct xdr_stream *xdr, const stateid_t *sid)
148 {
149         __be32 *p;
150 
151         p = xdr_reserve_space(xdr, NFS4_STATEID_SIZE);
152         *p++ = cpu_to_be32(sid->si_generation);
153         xdr_encode_opaque_fixed(p, &sid->si_opaque, NFS4_STATEID_OTHER_SIZE);
154 }
155 
156 /*
157  * sessionid4
158  *
159  *      typedef opaque sessionid4[NFS4_SESSIONID_SIZE];
160  */
161 static void encode_sessionid4(struct xdr_stream *xdr,
162                               const struct nfsd4_session *session)
163 {
164         __be32 *p;
165 
166         p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN);
167         xdr_encode_opaque_fixed(p, session->se_sessionid.data,
168                                         NFS4_MAX_SESSIONID_LEN);
169 }
170 
171 /*
172  * nfsstat4
173  */
174 static const struct {
175         int stat;
176         int errno;
177 } nfs_cb_errtbl[] = {
178         { NFS4_OK,              0               },
179         { NFS4ERR_PERM,         -EPERM          },
180         { NFS4ERR_NOENT,        -ENOENT         },
181         { NFS4ERR_IO,           -EIO            },
182         { NFS4ERR_NXIO,         -ENXIO          },
183         { NFS4ERR_ACCESS,       -EACCES         },
184         { NFS4ERR_EXIST,        -EEXIST         },
185         { NFS4ERR_XDEV,         -EXDEV          },
186         { NFS4ERR_NOTDIR,       -ENOTDIR        },
187         { NFS4ERR_ISDIR,        -EISDIR         },
188         { NFS4ERR_INVAL,        -EINVAL         },
189         { NFS4ERR_FBIG,         -EFBIG          },
190         { NFS4ERR_NOSPC,        -ENOSPC         },
191         { NFS4ERR_ROFS,         -EROFS          },
192         { NFS4ERR_MLINK,        -EMLINK         },
193         { NFS4ERR_NAMETOOLONG,  -ENAMETOOLONG   },
194         { NFS4ERR_NOTEMPTY,     -ENOTEMPTY      },
195         { NFS4ERR_DQUOT,        -EDQUOT         },
196         { NFS4ERR_STALE,        -ESTALE         },
197         { NFS4ERR_BADHANDLE,    -EBADHANDLE     },
198         { NFS4ERR_BAD_COOKIE,   -EBADCOOKIE     },
199         { NFS4ERR_NOTSUPP,      -ENOTSUPP       },
200         { NFS4ERR_TOOSMALL,     -ETOOSMALL      },
201         { NFS4ERR_SERVERFAULT,  -ESERVERFAULT   },
202         { NFS4ERR_BADTYPE,      -EBADTYPE       },
203         { NFS4ERR_LOCKED,       -EAGAIN         },
204         { NFS4ERR_RESOURCE,     -EREMOTEIO      },
205         { NFS4ERR_SYMLINK,      -ELOOP          },
206         { NFS4ERR_OP_ILLEGAL,   -EOPNOTSUPP     },
207         { NFS4ERR_DEADLOCK,     -EDEADLK        },
208         { -1,                   -EIO            }
209 };
210 
211 /*
212  * If we cannot translate the error, the recovery routines should
213  * handle it.
214  *
215  * Note: remaining NFSv4 error codes have values > 10000, so should
216  * not conflict with native Linux error codes.
217  */
218 static int nfs_cb_stat_to_errno(int status)
219 {
220         int i;
221 
222         for (i = 0; nfs_cb_errtbl[i].stat != -1; i++) {
223                 if (nfs_cb_errtbl[i].stat == status)
224                         return nfs_cb_errtbl[i].errno;
225         }
226 
227         dprintk("NFSD: Unrecognized NFS CB status value: %u\n", status);
228         return -status;
229 }
230 
231 static int decode_cb_op_status(struct xdr_stream *xdr, enum nfs_opnum4 expected,
232                                enum nfsstat4 *status)
233 {
234         __be32 *p;
235         u32 op;
236 
237         p = xdr_inline_decode(xdr, 4 + 4);
238         if (unlikely(p == NULL))
239                 goto out_overflow;
240         op = be32_to_cpup(p++);
241         if (unlikely(op != expected))
242                 goto out_unexpected;
243         *status = be32_to_cpup(p);
244         return 0;
245 out_overflow:
246         print_overflow_msg(__func__, xdr);
247         return -EIO;
248 out_unexpected:
249         dprintk("NFSD: Callback server returned operation %d but "
250                 "we issued a request for %d\n", op, expected);
251         return -EIO;
252 }
253 
254 /*
255  * CB_COMPOUND4args
256  *
257  *      struct CB_COMPOUND4args {
258  *              utf8str_cs      tag;
259  *              uint32_t        minorversion;
260  *              uint32_t        callback_ident;
261  *              nfs_cb_argop4   argarray<>;
262  *      };
263 */
264 static void encode_cb_compound4args(struct xdr_stream *xdr,
265                                     struct nfs4_cb_compound_hdr *hdr)
266 {
267         __be32 * p;
268 
269         p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4);
270         p = xdr_encode_empty_array(p);          /* empty tag */
271         *p++ = cpu_to_be32(hdr->minorversion);
272         *p++ = cpu_to_be32(hdr->ident);
273 
274         hdr->nops_p = p;
275         *p = cpu_to_be32(hdr->nops);            /* argarray element count */
276 }
277 
278 /*
279  * Update argarray element count
280  */
281 static void encode_cb_nops(struct nfs4_cb_compound_hdr *hdr)
282 {
283         BUG_ON(hdr->nops > NFS4_MAX_BACK_CHANNEL_OPS);
284         *hdr->nops_p = cpu_to_be32(hdr->nops);
285 }
286 
287 /*
288  * CB_COMPOUND4res
289  *
290  *      struct CB_COMPOUND4res {
291  *              nfsstat4        status;
292  *              utf8str_cs      tag;
293  *              nfs_cb_resop4   resarray<>;
294  *      };
295  */
296 static int decode_cb_compound4res(struct xdr_stream *xdr,
297                                   struct nfs4_cb_compound_hdr *hdr)
298 {
299         u32 length;
300         __be32 *p;
301 
302         p = xdr_inline_decode(xdr, 4 + 4);
303         if (unlikely(p == NULL))
304                 goto out_overflow;
305         hdr->status = be32_to_cpup(p++);
306         /* Ignore the tag */
307         length = be32_to_cpup(p++);
308         p = xdr_inline_decode(xdr, length + 4);
309         if (unlikely(p == NULL))
310                 goto out_overflow;
311         hdr->nops = be32_to_cpup(p);
312         return 0;
313 out_overflow:
314         print_overflow_msg(__func__, xdr);
315         return -EIO;
316 }
317 
318 /*
319  * CB_RECALL4args
320  *
321  *      struct CB_RECALL4args {
322  *              stateid4        stateid;
323  *              bool            truncate;
324  *              nfs_fh4         fh;
325  *      };
326  */
327 static void encode_cb_recall4args(struct xdr_stream *xdr,
328                                   const struct nfs4_delegation *dp,
329                                   struct nfs4_cb_compound_hdr *hdr)
330 {
331         __be32 *p;
332 
333         encode_nfs_cb_opnum4(xdr, OP_CB_RECALL);
334         encode_stateid4(xdr, &dp->dl_stid.sc_stateid);
335 
336         p = xdr_reserve_space(xdr, 4);
337         *p++ = xdr_zero;                        /* truncate */
338 
339         encode_nfs_fh4(xdr, &dp->dl_fh);
340 
341         hdr->nops++;
342 }
343 
344 /*
345  * CB_SEQUENCE4args
346  *
347  *      struct CB_SEQUENCE4args {
348  *              sessionid4              csa_sessionid;
349  *              sequenceid4             csa_sequenceid;
350  *              slotid4                 csa_slotid;
351  *              slotid4                 csa_highest_slotid;
352  *              bool                    csa_cachethis;
353  *              referring_call_list4    csa_referring_call_lists<>;
354  *      };
355  */
356 static void encode_cb_sequence4args(struct xdr_stream *xdr,
357                                     const struct nfsd4_callback *cb,
358                                     struct nfs4_cb_compound_hdr *hdr)
359 {
360         struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
361         __be32 *p;
362 
363         if (hdr->minorversion == 0)
364                 return;
365 
366         encode_nfs_cb_opnum4(xdr, OP_CB_SEQUENCE);
367         encode_sessionid4(xdr, session);
368 
369         p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4 + 4);
370         *p++ = cpu_to_be32(session->se_cb_seq_nr);      /* csa_sequenceid */
371         *p++ = xdr_zero;                        /* csa_slotid */
372         *p++ = xdr_zero;                        /* csa_highest_slotid */
373         *p++ = xdr_zero;                        /* csa_cachethis */
374         xdr_encode_empty_array(p);              /* csa_referring_call_lists */
375 
376         hdr->nops++;
377 }
378 
379 /*
380  * CB_SEQUENCE4resok
381  *
382  *      struct CB_SEQUENCE4resok {
383  *              sessionid4      csr_sessionid;
384  *              sequenceid4     csr_sequenceid;
385  *              slotid4         csr_slotid;
386  *              slotid4         csr_highest_slotid;
387  *              slotid4         csr_target_highest_slotid;
388  *      };
389  *
390  *      union CB_SEQUENCE4res switch (nfsstat4 csr_status) {
391  *      case NFS4_OK:
392  *              CB_SEQUENCE4resok       csr_resok4;
393  *      default:
394  *              void;
395  *      };
396  *
397  * Our current back channel implmentation supports a single backchannel
398  * with a single slot.
399  */
400 static int decode_cb_sequence4resok(struct xdr_stream *xdr,
401                                     struct nfsd4_callback *cb)
402 {
403         struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
404         struct nfs4_sessionid id;
405         int status;
406         __be32 *p;
407         u32 dummy;
408 
409         status = -ESERVERFAULT;
410 
411         /*
412          * If the server returns different values for sessionID, slotID or
413          * sequence number, the server is looney tunes.
414          */
415         p = xdr_inline_decode(xdr, NFS4_MAX_SESSIONID_LEN + 4 + 4 + 4 + 4);
416         if (unlikely(p == NULL))
417                 goto out_overflow;
418         memcpy(id.data, p, NFS4_MAX_SESSIONID_LEN);
419         if (memcmp(id.data, session->se_sessionid.data,
420                                         NFS4_MAX_SESSIONID_LEN) != 0) {
421                 dprintk("NFS: %s Invalid session id\n", __func__);
422                 goto out;
423         }
424         p += XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN);
425 
426         dummy = be32_to_cpup(p++);
427         if (dummy != session->se_cb_seq_nr) {
428                 dprintk("NFS: %s Invalid sequence number\n", __func__);
429                 goto out;
430         }
431 
432         dummy = be32_to_cpup(p++);
433         if (dummy != 0) {
434                 dprintk("NFS: %s Invalid slotid\n", __func__);
435                 goto out;
436         }
437 
438         /*
439          * FIXME: process highest slotid and target highest slotid
440          */
441         status = 0;
442 out:
443         if (status)
444                 nfsd4_mark_cb_fault(cb->cb_clp, status);
445         return status;
446 out_overflow:
447         print_overflow_msg(__func__, xdr);
448         return -EIO;
449 }
450 
451 static int decode_cb_sequence4res(struct xdr_stream *xdr,
452                                   struct nfsd4_callback *cb)
453 {
454         enum nfsstat4 nfserr;
455         int status;
456 
457         if (cb->cb_minorversion == 0)
458                 return 0;
459 
460         status = decode_cb_op_status(xdr, OP_CB_SEQUENCE, &nfserr);
461         if (unlikely(status))
462                 goto out;
463         if (unlikely(nfserr != NFS4_OK))
464                 goto out_default;
465         status = decode_cb_sequence4resok(xdr, cb);
466 out:
467         return status;
468 out_default:
469         return nfs_cb_stat_to_errno(nfserr);
470 }
471 
472 /*
473  * NFSv4.0 and NFSv4.1 XDR encode functions
474  *
475  * NFSv4.0 callback argument types are defined in section 15 of RFC
476  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
477  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
478  * Protocol".
479  */
480 
481 /*
482  * NB: Without this zero space reservation, callbacks over krb5p fail
483  */
484 static void nfs4_xdr_enc_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
485                                  void *__unused)
486 {
487         xdr_reserve_space(xdr, 0);
488 }
489 
490 /*
491  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
492  */
493 static void nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, struct xdr_stream *xdr,
494                                    const struct nfsd4_callback *cb)
495 {
496         const struct nfs4_delegation *args = cb->cb_op;
497         struct nfs4_cb_compound_hdr hdr = {
498                 .ident = cb->cb_clp->cl_cb_ident,
499                 .minorversion = cb->cb_minorversion,
500         };
501 
502         encode_cb_compound4args(xdr, &hdr);
503         encode_cb_sequence4args(xdr, cb, &hdr);
504         encode_cb_recall4args(xdr, args, &hdr);
505         encode_cb_nops(&hdr);
506 }
507 
508 
509 /*
510  * NFSv4.0 and NFSv4.1 XDR decode functions
511  *
512  * NFSv4.0 callback result types are defined in section 15 of RFC
513  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
514  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
515  * Protocol".
516  */
517 
518 static int nfs4_xdr_dec_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
519                                 void *__unused)
520 {
521         return 0;
522 }
523 
524 /*
525  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
526  */
527 static int nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp,
528                                   struct xdr_stream *xdr,
529                                   struct nfsd4_callback *cb)
530 {
531         struct nfs4_cb_compound_hdr hdr;
532         enum nfsstat4 nfserr;
533         int status;
534 
535         status = decode_cb_compound4res(xdr, &hdr);
536         if (unlikely(status))
537                 goto out;
538 
539         if (cb != NULL) {
540                 status = decode_cb_sequence4res(xdr, cb);
541                 if (unlikely(status))
542                         goto out;
543         }
544 
545         status = decode_cb_op_status(xdr, OP_CB_RECALL, &nfserr);
546         if (unlikely(status))
547                 goto out;
548         if (unlikely(nfserr != NFS4_OK))
549                 status = nfs_cb_stat_to_errno(nfserr);
550 out:
551         return status;
552 }
553 
554 /*
555  * RPC procedure tables
556  */
557 #define PROC(proc, call, argtype, restype)                              \
558 [NFSPROC4_CLNT_##proc] = {                                              \
559         .p_proc    = NFSPROC4_CB_##call,                                \
560         .p_encode  = (kxdreproc_t)nfs4_xdr_enc_##argtype,               \
561         .p_decode  = (kxdrdproc_t)nfs4_xdr_dec_##restype,               \
562         .p_arglen  = NFS4_enc_##argtype##_sz,                           \
563         .p_replen  = NFS4_dec_##restype##_sz,                           \
564         .p_statidx = NFSPROC4_CB_##call,                                \
565         .p_name    = #proc,                                             \
566 }
567 
568 static struct rpc_procinfo nfs4_cb_procedures[] = {
569         PROC(CB_NULL,   NULL,           cb_null,        cb_null),
570         PROC(CB_RECALL, COMPOUND,       cb_recall,      cb_recall),
571 };
572 
573 static struct rpc_version nfs_cb_version4 = {
574 /*
575  * Note on the callback rpc program version number: despite language in rfc
576  * 5661 section 18.36.3 requiring servers to use 4 in this field, the
577  * official xdr descriptions for both 4.0 and 4.1 specify version 1, and
578  * in practice that appears to be what implementations use.  The section
579  * 18.36.3 language is expected to be fixed in an erratum.
580  */
581         .number                 = 1,
582         .nrprocs                = ARRAY_SIZE(nfs4_cb_procedures),
583         .procs                  = nfs4_cb_procedures
584 };
585 
586 static const struct rpc_version *nfs_cb_version[] = {
587         &nfs_cb_version4,
588 };
589 
590 static const struct rpc_program cb_program;
591 
592 static struct rpc_stat cb_stats = {
593         .program                = &cb_program
594 };
595 
596 #define NFS4_CALLBACK 0x40000000
597 static const struct rpc_program cb_program = {
598         .name                   = "nfs4_cb",
599         .number                 = NFS4_CALLBACK,
600         .nrvers                 = ARRAY_SIZE(nfs_cb_version),
601         .version                = nfs_cb_version,
602         .stats                  = &cb_stats,
603         .pipe_dir_name          = "nfsd4_cb",
604 };
605 
606 static int max_cb_time(struct net *net)
607 {
608         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
609         return max(nn->nfsd4_lease/10, (time_t)1) * HZ;
610 }
611 
612 static struct rpc_cred *callback_cred;
613 
614 int set_callback_cred(void)
615 {
616         if (callback_cred)
617                 return 0;
618         callback_cred = rpc_lookup_machine_cred("nfs");
619         if (!callback_cred)
620                 return -ENOMEM;
621         return 0;
622 }
623 
624 static struct rpc_cred *get_backchannel_cred(struct nfs4_client *clp, struct rpc_clnt *client, struct nfsd4_session *ses)
625 {
626         if (clp->cl_minorversion == 0) {
627                 return get_rpccred(callback_cred);
628         } else {
629                 struct rpc_auth *auth = client->cl_auth;
630                 struct auth_cred acred = {};
631 
632                 acred.uid = ses->se_cb_sec.uid;
633                 acred.gid = ses->se_cb_sec.gid;
634                 return auth->au_ops->lookup_cred(client->cl_auth, &acred, 0);
635         }
636 }
637 
638 static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn, struct nfsd4_session *ses)
639 {
640         int maxtime = max_cb_time(clp->net);
641         struct rpc_timeout      timeparms = {
642                 .to_initval     = maxtime,
643                 .to_retries     = 0,
644                 .to_maxval      = maxtime,
645         };
646         struct rpc_create_args args = {
647                 .net            = clp->net,
648                 .address        = (struct sockaddr *) &conn->cb_addr,
649                 .addrsize       = conn->cb_addrlen,
650                 .saddress       = (struct sockaddr *) &conn->cb_saddr,
651                 .timeout        = &timeparms,
652                 .program        = &cb_program,
653                 .version        = 0,
654                 .flags          = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
655         };
656         struct rpc_clnt *client;
657         struct rpc_cred *cred;
658 
659         if (clp->cl_minorversion == 0) {
660                 if (!clp->cl_cred.cr_principal &&
661                                 (clp->cl_cred.cr_flavor >= RPC_AUTH_GSS_KRB5))
662                         return -EINVAL;
663                 args.client_name = clp->cl_cred.cr_principal;
664                 args.prognumber = conn->cb_prog,
665                 args.protocol = XPRT_TRANSPORT_TCP;
666                 args.authflavor = clp->cl_cred.cr_flavor;
667                 clp->cl_cb_ident = conn->cb_ident;
668         } else {
669                 if (!conn->cb_xprt)
670                         return -EINVAL;
671                 clp->cl_cb_conn.cb_xprt = conn->cb_xprt;
672                 clp->cl_cb_session = ses;
673                 args.bc_xprt = conn->cb_xprt;
674                 args.prognumber = clp->cl_cb_session->se_cb_prog;
675                 args.protocol = conn->cb_xprt->xpt_class->xcl_ident |
676                                 XPRT_TRANSPORT_BC;
677                 args.authflavor = ses->se_cb_sec.flavor;
678         }
679         /* Create RPC client */
680         client = rpc_create(&args);
681         if (IS_ERR(client)) {
682                 dprintk("NFSD: couldn't create callback client: %ld\n",
683                         PTR_ERR(client));
684                 return PTR_ERR(client);
685         }
686         cred = get_backchannel_cred(clp, client, ses);
687         if (IS_ERR(cred)) {
688                 rpc_shutdown_client(client);
689                 return PTR_ERR(cred);
690         }
691         clp->cl_cb_client = client;
692         clp->cl_cb_cred = cred;
693         return 0;
694 }
695 
696 static void warn_no_callback_path(struct nfs4_client *clp, int reason)
697 {
698         dprintk("NFSD: warning: no callback path to client %.*s: error %d\n",
699                 (int)clp->cl_name.len, clp->cl_name.data, reason);
700 }
701 
702 static void nfsd4_mark_cb_down(struct nfs4_client *clp, int reason)
703 {
704         clp->cl_cb_state = NFSD4_CB_DOWN;
705         warn_no_callback_path(clp, reason);
706 }
707 
708 static void nfsd4_mark_cb_fault(struct nfs4_client *clp, int reason)
709 {
710         clp->cl_cb_state = NFSD4_CB_FAULT;
711         warn_no_callback_path(clp, reason);
712 }
713 
714 static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
715 {
716         struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
717 
718         if (task->tk_status)
719                 nfsd4_mark_cb_down(clp, task->tk_status);
720         else
721                 clp->cl_cb_state = NFSD4_CB_UP;
722 }
723 
724 static const struct rpc_call_ops nfsd4_cb_probe_ops = {
725         /* XXX: release method to ensure we set the cb channel down if
726          * necessary on early failure? */
727         .rpc_call_done = nfsd4_cb_probe_done,
728 };
729 
730 static struct workqueue_struct *callback_wq;
731 
732 static void run_nfsd4_cb(struct nfsd4_callback *cb)
733 {
734         queue_work(callback_wq, &cb->cb_work);
735 }
736 
737 static void do_probe_callback(struct nfs4_client *clp)
738 {
739         struct nfsd4_callback *cb = &clp->cl_cb_null;
740 
741         cb->cb_op = NULL;
742         cb->cb_clp = clp;
743 
744         cb->cb_msg.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_NULL];
745         cb->cb_msg.rpc_argp = NULL;
746         cb->cb_msg.rpc_resp = NULL;
747 
748         cb->cb_ops = &nfsd4_cb_probe_ops;
749 
750         run_nfsd4_cb(cb);
751 }
752 
753 /*
754  * Poke the callback thread to process any updates to the callback
755  * parameters, and send a null probe.
756  */
757 void nfsd4_probe_callback(struct nfs4_client *clp)
758 {
759         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
760         set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
761         do_probe_callback(clp);
762 }
763 
764 void nfsd4_probe_callback_sync(struct nfs4_client *clp)
765 {
766         nfsd4_probe_callback(clp);
767         flush_workqueue(callback_wq);
768 }
769 
770 void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *conn)
771 {
772         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
773         spin_lock(&clp->cl_lock);
774         memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn));
775         spin_unlock(&clp->cl_lock);
776 }
777 
778 /*
779  * There's currently a single callback channel slot.
780  * If the slot is available, then mark it busy.  Otherwise, set the
781  * thread for sleeping on the callback RPC wait queue.
782  */
783 static bool nfsd41_cb_get_slot(struct nfs4_client *clp, struct rpc_task *task)
784 {
785         if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
786                 rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
787                 /* Race breaker */
788                 if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
789                         dprintk("%s slot is busy\n", __func__);
790                         return false;
791                 }
792                 rpc_wake_up_queued_task(&clp->cl_cb_waitq, task);
793         }
794         return true;
795 }
796 
797 /*
798  * TODO: cb_sequence should support referring call lists, cachethis, multiple
799  * slots, and mark callback channel down on communication errors.
800  */
801 static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
802 {
803         struct nfsd4_callback *cb = calldata;
804         struct nfs4_client *clp = cb->cb_clp;
805         u32 minorversion = clp->cl_minorversion;
806 
807         cb->cb_minorversion = minorversion;
808         if (minorversion) {
809                 if (!nfsd41_cb_get_slot(clp, task))
810                         return;
811         }
812         spin_lock(&clp->cl_lock);
813         if (list_empty(&cb->cb_per_client)) {
814                 /* This is the first call, not a restart */
815                 cb->cb_done = false;
816                 list_add(&cb->cb_per_client, &clp->cl_callbacks);
817         }
818         spin_unlock(&clp->cl_lock);
819         rpc_call_start(task);
820 }
821 
822 static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
823 {
824         struct nfsd4_callback *cb = calldata;
825         struct nfs4_client *clp = cb->cb_clp;
826 
827         dprintk("%s: minorversion=%d\n", __func__,
828                 clp->cl_minorversion);
829 
830         if (clp->cl_minorversion) {
831                 /* No need for lock, access serialized in nfsd4_cb_prepare */
832                 ++clp->cl_cb_session->se_cb_seq_nr;
833                 clear_bit(0, &clp->cl_cb_slot_busy);
834                 rpc_wake_up_next(&clp->cl_cb_waitq);
835                 dprintk("%s: freed slot, new seqid=%d\n", __func__,
836                         clp->cl_cb_session->se_cb_seq_nr);
837 
838                 /* We're done looking into the sequence information */
839                 task->tk_msg.rpc_resp = NULL;
840         }
841 }
842 
843 
844 static void nfsd4_cb_recall_done(struct rpc_task *task, void *calldata)
845 {
846         struct nfsd4_callback *cb = calldata;
847         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
848         struct nfs4_client *clp = cb->cb_clp;
849         struct rpc_clnt *current_rpc_client = clp->cl_cb_client;
850 
851         nfsd4_cb_done(task, calldata);
852 
853         if (current_rpc_client != task->tk_client) {
854                 /* We're shutting down or changing cl_cb_client; leave
855                  * it to nfsd4_process_cb_update to restart the call if
856                  * necessary. */
857                 return;
858         }
859 
860         if (cb->cb_done)
861                 return;
862         switch (task->tk_status) {
863         case 0:
864                 cb->cb_done = true;
865                 return;
866         case -EBADHANDLE:
867         case -NFS4ERR_BAD_STATEID:
868                 /* Race: client probably got cb_recall
869                  * before open reply granting delegation */
870                 break;
871         default:
872                 /* Network partition? */
873                 nfsd4_mark_cb_down(clp, task->tk_status);
874         }
875         if (dp->dl_retries--) {
876                 rpc_delay(task, 2*HZ);
877                 task->tk_status = 0;
878                 rpc_restart_call_prepare(task);
879                 return;
880         }
881         nfsd4_mark_cb_down(clp, task->tk_status);
882         cb->cb_done = true;
883 }
884 
885 static void nfsd4_cb_recall_release(void *calldata)
886 {
887         struct nfsd4_callback *cb = calldata;
888         struct nfs4_client *clp = cb->cb_clp;
889         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
890 
891         if (cb->cb_done) {
892                 spin_lock(&clp->cl_lock);
893                 list_del(&cb->cb_per_client);
894                 spin_unlock(&clp->cl_lock);
895                 nfs4_put_delegation(dp);
896         }
897 }
898 
899 static const struct rpc_call_ops nfsd4_cb_recall_ops = {
900         .rpc_call_prepare = nfsd4_cb_prepare,
901         .rpc_call_done = nfsd4_cb_recall_done,
902         .rpc_release = nfsd4_cb_recall_release,
903 };
904 
905 int nfsd4_create_callback_queue(void)
906 {
907         callback_wq = create_singlethread_workqueue("nfsd4_callbacks");
908         if (!callback_wq)
909                 return -ENOMEM;
910         return 0;
911 }
912 
913 void nfsd4_destroy_callback_queue(void)
914 {
915         destroy_workqueue(callback_wq);
916 }
917 
918 /* must be called under the state lock */
919 void nfsd4_shutdown_callback(struct nfs4_client *clp)
920 {
921         set_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags);
922         /*
923          * Note this won't actually result in a null callback;
924          * instead, nfsd4_do_callback_rpc() will detect the killed
925          * client, destroy the rpc client, and stop:
926          */
927         do_probe_callback(clp);
928         flush_workqueue(callback_wq);
929 }
930 
931 static void nfsd4_release_cb(struct nfsd4_callback *cb)
932 {
933         if (cb->cb_ops->rpc_release)
934                 cb->cb_ops->rpc_release(cb);
935 }
936 
937 /* requires cl_lock: */
938 static struct nfsd4_conn * __nfsd4_find_backchannel(struct nfs4_client *clp)
939 {
940         struct nfsd4_session *s;
941         struct nfsd4_conn *c;
942 
943         list_for_each_entry(s, &clp->cl_sessions, se_perclnt) {
944                 list_for_each_entry(c, &s->se_conns, cn_persession) {
945                         if (c->cn_flags & NFS4_CDFC4_BACK)
946                                 return c;
947                 }
948         }
949         return NULL;
950 }
951 
952 static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
953 {
954         struct nfs4_cb_conn conn;
955         struct nfs4_client *clp = cb->cb_clp;
956         struct nfsd4_session *ses = NULL;
957         struct nfsd4_conn *c;
958         int err;
959 
960         /*
961          * This is either an update, or the client dying; in either case,
962          * kill the old client:
963          */
964         if (clp->cl_cb_client) {
965                 rpc_shutdown_client(clp->cl_cb_client);
966                 clp->cl_cb_client = NULL;
967                 put_rpccred(clp->cl_cb_cred);
968                 clp->cl_cb_cred = NULL;
969         }
970         if (clp->cl_cb_conn.cb_xprt) {
971                 svc_xprt_put(clp->cl_cb_conn.cb_xprt);
972                 clp->cl_cb_conn.cb_xprt = NULL;
973         }
974         if (test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags))
975                 return;
976         spin_lock(&clp->cl_lock);
977         /*
978          * Only serialized callback code is allowed to clear these
979          * flags; main nfsd code can only set them:
980          */
981         BUG_ON(!(clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK));
982         clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
983         memcpy(&conn, &cb->cb_clp->cl_cb_conn, sizeof(struct nfs4_cb_conn));
984         c = __nfsd4_find_backchannel(clp);
985         if (c) {
986                 svc_xprt_get(c->cn_xprt);
987                 conn.cb_xprt = c->cn_xprt;
988                 ses = c->cn_session;
989         }
990         spin_unlock(&clp->cl_lock);
991 
992         err = setup_callback_client(clp, &conn, ses);
993         if (err) {
994                 nfsd4_mark_cb_down(clp, err);
995                 return;
996         }
997         /* Yay, the callback channel's back! Restart any callbacks: */
998         list_for_each_entry(cb, &clp->cl_callbacks, cb_per_client)
999                 run_nfsd4_cb(cb);
1000 }
1001 
1002 static void nfsd4_do_callback_rpc(struct work_struct *w)
1003 {
1004         struct nfsd4_callback *cb = container_of(w, struct nfsd4_callback, cb_work);
1005         struct nfs4_client *clp = cb->cb_clp;
1006         struct rpc_clnt *clnt;
1007 
1008         if (clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK)
1009                 nfsd4_process_cb_update(cb);
1010 
1011         clnt = clp->cl_cb_client;
1012         if (!clnt) {
1013                 /* Callback channel broken, or client killed; give up: */
1014                 nfsd4_release_cb(cb);
1015                 return;
1016         }
1017         cb->cb_msg.rpc_cred = clp->cl_cb_cred;
1018         rpc_call_async(clnt, &cb->cb_msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN,
1019                         cb->cb_ops, cb);
1020 }
1021 
1022 void nfsd4_init_callback(struct nfsd4_callback *cb)
1023 {
1024         INIT_WORK(&cb->cb_work, nfsd4_do_callback_rpc);
1025 }
1026 
1027 void nfsd4_cb_recall(struct nfs4_delegation *dp)
1028 {
1029         struct nfsd4_callback *cb = &dp->dl_recall;
1030         struct nfs4_client *clp = dp->dl_stid.sc_client;
1031 
1032         dp->dl_retries = 1;
1033         cb->cb_op = dp;
1034         cb->cb_clp = clp;
1035         cb->cb_msg.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_RECALL];
1036         cb->cb_msg.rpc_argp = cb;
1037         cb->cb_msg.rpc_resp = cb;
1038 
1039         cb->cb_ops = &nfsd4_cb_recall_ops;
1040 
1041         INIT_LIST_HEAD(&cb->cb_per_client);
1042         cb->cb_done = true;
1043 
1044         run_nfsd4_cb(&dp->dl_recall);
1045 }
1046 

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