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0001 /*
0002  *  Copyright (c) 2001 The Regents of the University of Michigan.
0003  *  All rights reserved.
0004  *
0005  *  Kendrick Smith <kmsmith@umich.edu>
0006  *  Andy Adamson <andros@umich.edu>
0007  *
0008  *  Redistribution and use in source and binary forms, with or without
0009  *  modification, are permitted provided that the following conditions
0010  *  are met:
0011  *
0012  *  1. Redistributions of source code must retain the above copyright
0013  *     notice, this list of conditions and the following disclaimer.
0014  *  2. Redistributions in binary form must reproduce the above copyright
0015  *     notice, this list of conditions and the following disclaimer in the
0016  *     documentation and/or other materials provided with the distribution.
0017  *  3. Neither the name of the University nor the names of its
0018  *     contributors may be used to endorse or promote products derived
0019  *     from this software without specific prior written permission.
0020  *
0021  *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
0022  *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
0023  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
0024  *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
0025  *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0026  *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0027  *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
0028  *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
0029  *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
0030  *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
0031  *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
0032  */
0033 
0034 #include <linux/sunrpc/clnt.h>
0035 #include <linux/sunrpc/xprt.h>
0036 #include <linux/sunrpc/svc_xprt.h>
0037 #include <linux/slab.h>
0038 #include "nfsd.h"
0039 #include "state.h"
0040 #include "netns.h"
0041 #include "trace.h"
0042 #include "xdr4cb.h"
0043 #include "xdr4.h"
0044 
0045 #define NFSDDBG_FACILITY                NFSDDBG_PROC
0046 
0047 static void nfsd4_mark_cb_fault(struct nfs4_client *, int reason);
0048 
0049 #define NFSPROC4_CB_NULL 0
0050 #define NFSPROC4_CB_COMPOUND 1
0051 
0052 /* Index of predefined Linux callback client operations */
0053 
0054 struct nfs4_cb_compound_hdr {
0055     /* args */
0056     u32     ident;  /* minorversion 0 only */
0057     u32     nops;
0058     __be32      *nops_p;
0059     u32     minorversion;
0060     /* res */
0061     int     status;
0062 };
0063 
0064 static __be32 *xdr_encode_empty_array(__be32 *p)
0065 {
0066     *p++ = xdr_zero;
0067     return p;
0068 }
0069 
0070 /*
0071  * Encode/decode NFSv4 CB basic data types
0072  *
0073  * Basic NFSv4 callback data types are defined in section 15 of RFC
0074  * 3530: "Network File System (NFS) version 4 Protocol" and section
0075  * 20 of RFC 5661: "Network File System (NFS) Version 4 Minor Version
0076  * 1 Protocol"
0077  */
0078 
0079 /*
0080  *  nfs_cb_opnum4
0081  *
0082  *  enum nfs_cb_opnum4 {
0083  *      OP_CB_GETATTR       = 3,
0084  *        ...
0085  *  };
0086  */
0087 enum nfs_cb_opnum4 {
0088     OP_CB_GETATTR           = 3,
0089     OP_CB_RECALL            = 4,
0090     OP_CB_LAYOUTRECALL      = 5,
0091     OP_CB_NOTIFY            = 6,
0092     OP_CB_PUSH_DELEG        = 7,
0093     OP_CB_RECALL_ANY        = 8,
0094     OP_CB_RECALLABLE_OBJ_AVAIL  = 9,
0095     OP_CB_RECALL_SLOT       = 10,
0096     OP_CB_SEQUENCE          = 11,
0097     OP_CB_WANTS_CANCELLED       = 12,
0098     OP_CB_NOTIFY_LOCK       = 13,
0099     OP_CB_NOTIFY_DEVICEID       = 14,
0100     OP_CB_OFFLOAD           = 15,
0101     OP_CB_ILLEGAL           = 10044
0102 };
0103 
0104 static void encode_nfs_cb_opnum4(struct xdr_stream *xdr, enum nfs_cb_opnum4 op)
0105 {
0106     __be32 *p;
0107 
0108     p = xdr_reserve_space(xdr, 4);
0109     *p = cpu_to_be32(op);
0110 }
0111 
0112 /*
0113  * nfs_fh4
0114  *
0115  *  typedef opaque nfs_fh4<NFS4_FHSIZE>;
0116  */
0117 static void encode_nfs_fh4(struct xdr_stream *xdr, const struct knfsd_fh *fh)
0118 {
0119     u32 length = fh->fh_size;
0120     __be32 *p;
0121 
0122     BUG_ON(length > NFS4_FHSIZE);
0123     p = xdr_reserve_space(xdr, 4 + length);
0124     xdr_encode_opaque(p, &fh->fh_raw, length);
0125 }
0126 
0127 /*
0128  * stateid4
0129  *
0130  *  struct stateid4 {
0131  *      uint32_t    seqid;
0132  *      opaque      other[12];
0133  *  };
0134  */
0135 static void encode_stateid4(struct xdr_stream *xdr, const stateid_t *sid)
0136 {
0137     __be32 *p;
0138 
0139     p = xdr_reserve_space(xdr, NFS4_STATEID_SIZE);
0140     *p++ = cpu_to_be32(sid->si_generation);
0141     xdr_encode_opaque_fixed(p, &sid->si_opaque, NFS4_STATEID_OTHER_SIZE);
0142 }
0143 
0144 /*
0145  * sessionid4
0146  *
0147  *  typedef opaque sessionid4[NFS4_SESSIONID_SIZE];
0148  */
0149 static void encode_sessionid4(struct xdr_stream *xdr,
0150                   const struct nfsd4_session *session)
0151 {
0152     __be32 *p;
0153 
0154     p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN);
0155     xdr_encode_opaque_fixed(p, session->se_sessionid.data,
0156                     NFS4_MAX_SESSIONID_LEN);
0157 }
0158 
0159 /*
0160  * nfsstat4
0161  */
0162 static const struct {
0163     int stat;
0164     int errno;
0165 } nfs_cb_errtbl[] = {
0166     { NFS4_OK,      0       },
0167     { NFS4ERR_PERM,     -EPERM      },
0168     { NFS4ERR_NOENT,    -ENOENT     },
0169     { NFS4ERR_IO,       -EIO        },
0170     { NFS4ERR_NXIO,     -ENXIO      },
0171     { NFS4ERR_ACCESS,   -EACCES     },
0172     { NFS4ERR_EXIST,    -EEXIST     },
0173     { NFS4ERR_XDEV,     -EXDEV      },
0174     { NFS4ERR_NOTDIR,   -ENOTDIR    },
0175     { NFS4ERR_ISDIR,    -EISDIR     },
0176     { NFS4ERR_INVAL,    -EINVAL     },
0177     { NFS4ERR_FBIG,     -EFBIG      },
0178     { NFS4ERR_NOSPC,    -ENOSPC     },
0179     { NFS4ERR_ROFS,     -EROFS      },
0180     { NFS4ERR_MLINK,    -EMLINK     },
0181     { NFS4ERR_NAMETOOLONG,  -ENAMETOOLONG   },
0182     { NFS4ERR_NOTEMPTY, -ENOTEMPTY  },
0183     { NFS4ERR_DQUOT,    -EDQUOT     },
0184     { NFS4ERR_STALE,    -ESTALE     },
0185     { NFS4ERR_BADHANDLE,    -EBADHANDLE },
0186     { NFS4ERR_BAD_COOKIE,   -EBADCOOKIE },
0187     { NFS4ERR_NOTSUPP,  -ENOTSUPP   },
0188     { NFS4ERR_TOOSMALL, -ETOOSMALL  },
0189     { NFS4ERR_SERVERFAULT,  -ESERVERFAULT   },
0190     { NFS4ERR_BADTYPE,  -EBADTYPE   },
0191     { NFS4ERR_LOCKED,   -EAGAIN     },
0192     { NFS4ERR_RESOURCE, -EREMOTEIO  },
0193     { NFS4ERR_SYMLINK,  -ELOOP      },
0194     { NFS4ERR_OP_ILLEGAL,   -EOPNOTSUPP },
0195     { NFS4ERR_DEADLOCK, -EDEADLK    },
0196     { -1,           -EIO        }
0197 };
0198 
0199 /*
0200  * If we cannot translate the error, the recovery routines should
0201  * handle it.
0202  *
0203  * Note: remaining NFSv4 error codes have values > 10000, so should
0204  * not conflict with native Linux error codes.
0205  */
0206 static int nfs_cb_stat_to_errno(int status)
0207 {
0208     int i;
0209 
0210     for (i = 0; nfs_cb_errtbl[i].stat != -1; i++) {
0211         if (nfs_cb_errtbl[i].stat == status)
0212             return nfs_cb_errtbl[i].errno;
0213     }
0214 
0215     dprintk("NFSD: Unrecognized NFS CB status value: %u\n", status);
0216     return -status;
0217 }
0218 
0219 static int decode_cb_op_status(struct xdr_stream *xdr,
0220                    enum nfs_cb_opnum4 expected, int *status)
0221 {
0222     __be32 *p;
0223     u32 op;
0224 
0225     p = xdr_inline_decode(xdr, 4 + 4);
0226     if (unlikely(p == NULL))
0227         goto out_overflow;
0228     op = be32_to_cpup(p++);
0229     if (unlikely(op != expected))
0230         goto out_unexpected;
0231     *status = nfs_cb_stat_to_errno(be32_to_cpup(p));
0232     return 0;
0233 out_overflow:
0234     return -EIO;
0235 out_unexpected:
0236     dprintk("NFSD: Callback server returned operation %d but "
0237         "we issued a request for %d\n", op, expected);
0238     return -EIO;
0239 }
0240 
0241 /*
0242  * CB_COMPOUND4args
0243  *
0244  *  struct CB_COMPOUND4args {
0245  *      utf8str_cs  tag;
0246  *      uint32_t    minorversion;
0247  *      uint32_t    callback_ident;
0248  *      nfs_cb_argop4   argarray<>;
0249  *  };
0250 */
0251 static void encode_cb_compound4args(struct xdr_stream *xdr,
0252                     struct nfs4_cb_compound_hdr *hdr)
0253 {
0254     __be32 * p;
0255 
0256     p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4);
0257     p = xdr_encode_empty_array(p);      /* empty tag */
0258     *p++ = cpu_to_be32(hdr->minorversion);
0259     *p++ = cpu_to_be32(hdr->ident);
0260 
0261     hdr->nops_p = p;
0262     *p = cpu_to_be32(hdr->nops);        /* argarray element count */
0263 }
0264 
0265 /*
0266  * Update argarray element count
0267  */
0268 static void encode_cb_nops(struct nfs4_cb_compound_hdr *hdr)
0269 {
0270     BUG_ON(hdr->nops > NFS4_MAX_BACK_CHANNEL_OPS);
0271     *hdr->nops_p = cpu_to_be32(hdr->nops);
0272 }
0273 
0274 /*
0275  * CB_COMPOUND4res
0276  *
0277  *  struct CB_COMPOUND4res {
0278  *      nfsstat4    status;
0279  *      utf8str_cs  tag;
0280  *      nfs_cb_resop4   resarray<>;
0281  *  };
0282  */
0283 static int decode_cb_compound4res(struct xdr_stream *xdr,
0284                   struct nfs4_cb_compound_hdr *hdr)
0285 {
0286     u32 length;
0287     __be32 *p;
0288 
0289     p = xdr_inline_decode(xdr, 4 + 4);
0290     if (unlikely(p == NULL))
0291         goto out_overflow;
0292     hdr->status = be32_to_cpup(p++);
0293     /* Ignore the tag */
0294     length = be32_to_cpup(p++);
0295     p = xdr_inline_decode(xdr, length + 4);
0296     if (unlikely(p == NULL))
0297         goto out_overflow;
0298     p += XDR_QUADLEN(length);
0299     hdr->nops = be32_to_cpup(p);
0300     return 0;
0301 out_overflow:
0302     return -EIO;
0303 }
0304 
0305 /*
0306  * CB_RECALL4args
0307  *
0308  *  struct CB_RECALL4args {
0309  *      stateid4    stateid;
0310  *      bool        truncate;
0311  *      nfs_fh4     fh;
0312  *  };
0313  */
0314 static void encode_cb_recall4args(struct xdr_stream *xdr,
0315                   const struct nfs4_delegation *dp,
0316                   struct nfs4_cb_compound_hdr *hdr)
0317 {
0318     __be32 *p;
0319 
0320     encode_nfs_cb_opnum4(xdr, OP_CB_RECALL);
0321     encode_stateid4(xdr, &dp->dl_stid.sc_stateid);
0322 
0323     p = xdr_reserve_space(xdr, 4);
0324     *p++ = xdr_zero;            /* truncate */
0325 
0326     encode_nfs_fh4(xdr, &dp->dl_stid.sc_file->fi_fhandle);
0327 
0328     hdr->nops++;
0329 }
0330 
0331 /*
0332  * CB_SEQUENCE4args
0333  *
0334  *  struct CB_SEQUENCE4args {
0335  *      sessionid4      csa_sessionid;
0336  *      sequenceid4     csa_sequenceid;
0337  *      slotid4         csa_slotid;
0338  *      slotid4         csa_highest_slotid;
0339  *      bool            csa_cachethis;
0340  *      referring_call_list4    csa_referring_call_lists<>;
0341  *  };
0342  */
0343 static void encode_cb_sequence4args(struct xdr_stream *xdr,
0344                     const struct nfsd4_callback *cb,
0345                     struct nfs4_cb_compound_hdr *hdr)
0346 {
0347     struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
0348     __be32 *p;
0349 
0350     if (hdr->minorversion == 0)
0351         return;
0352 
0353     encode_nfs_cb_opnum4(xdr, OP_CB_SEQUENCE);
0354     encode_sessionid4(xdr, session);
0355 
0356     p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4 + 4);
0357     *p++ = cpu_to_be32(session->se_cb_seq_nr);  /* csa_sequenceid */
0358     *p++ = xdr_zero;            /* csa_slotid */
0359     *p++ = xdr_zero;            /* csa_highest_slotid */
0360     *p++ = xdr_zero;            /* csa_cachethis */
0361     xdr_encode_empty_array(p);      /* csa_referring_call_lists */
0362 
0363     hdr->nops++;
0364 }
0365 
0366 /*
0367  * CB_SEQUENCE4resok
0368  *
0369  *  struct CB_SEQUENCE4resok {
0370  *      sessionid4  csr_sessionid;
0371  *      sequenceid4 csr_sequenceid;
0372  *      slotid4     csr_slotid;
0373  *      slotid4     csr_highest_slotid;
0374  *      slotid4     csr_target_highest_slotid;
0375  *  };
0376  *
0377  *  union CB_SEQUENCE4res switch (nfsstat4 csr_status) {
0378  *  case NFS4_OK:
0379  *      CB_SEQUENCE4resok   csr_resok4;
0380  *  default:
0381  *      void;
0382  *  };
0383  *
0384  * Our current back channel implmentation supports a single backchannel
0385  * with a single slot.
0386  */
0387 static int decode_cb_sequence4resok(struct xdr_stream *xdr,
0388                     struct nfsd4_callback *cb)
0389 {
0390     struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
0391     int status = -ESERVERFAULT;
0392     __be32 *p;
0393     u32 dummy;
0394 
0395     /*
0396      * If the server returns different values for sessionID, slotID or
0397      * sequence number, the server is looney tunes.
0398      */
0399     p = xdr_inline_decode(xdr, NFS4_MAX_SESSIONID_LEN + 4 + 4 + 4 + 4);
0400     if (unlikely(p == NULL))
0401         goto out_overflow;
0402 
0403     if (memcmp(p, session->se_sessionid.data, NFS4_MAX_SESSIONID_LEN)) {
0404         dprintk("NFS: %s Invalid session id\n", __func__);
0405         goto out;
0406     }
0407     p += XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN);
0408 
0409     dummy = be32_to_cpup(p++);
0410     if (dummy != session->se_cb_seq_nr) {
0411         dprintk("NFS: %s Invalid sequence number\n", __func__);
0412         goto out;
0413     }
0414 
0415     dummy = be32_to_cpup(p++);
0416     if (dummy != 0) {
0417         dprintk("NFS: %s Invalid slotid\n", __func__);
0418         goto out;
0419     }
0420 
0421     /*
0422      * FIXME: process highest slotid and target highest slotid
0423      */
0424     status = 0;
0425 out:
0426     cb->cb_seq_status = status;
0427     return status;
0428 out_overflow:
0429     status = -EIO;
0430     goto out;
0431 }
0432 
0433 static int decode_cb_sequence4res(struct xdr_stream *xdr,
0434                   struct nfsd4_callback *cb)
0435 {
0436     int status;
0437 
0438     if (cb->cb_clp->cl_minorversion == 0)
0439         return 0;
0440 
0441     status = decode_cb_op_status(xdr, OP_CB_SEQUENCE, &cb->cb_seq_status);
0442     if (unlikely(status || cb->cb_seq_status))
0443         return status;
0444 
0445     return decode_cb_sequence4resok(xdr, cb);
0446 }
0447 
0448 /*
0449  * NFSv4.0 and NFSv4.1 XDR encode functions
0450  *
0451  * NFSv4.0 callback argument types are defined in section 15 of RFC
0452  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
0453  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
0454  * Protocol".
0455  */
0456 
0457 /*
0458  * NB: Without this zero space reservation, callbacks over krb5p fail
0459  */
0460 static void nfs4_xdr_enc_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
0461                  const void *__unused)
0462 {
0463     xdr_reserve_space(xdr, 0);
0464 }
0465 
0466 /*
0467  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
0468  */
0469 static void nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, struct xdr_stream *xdr,
0470                    const void *data)
0471 {
0472     const struct nfsd4_callback *cb = data;
0473     const struct nfs4_delegation *dp = cb_to_delegation(cb);
0474     struct nfs4_cb_compound_hdr hdr = {
0475         .ident = cb->cb_clp->cl_cb_ident,
0476         .minorversion = cb->cb_clp->cl_minorversion,
0477     };
0478 
0479     encode_cb_compound4args(xdr, &hdr);
0480     encode_cb_sequence4args(xdr, cb, &hdr);
0481     encode_cb_recall4args(xdr, dp, &hdr);
0482     encode_cb_nops(&hdr);
0483 }
0484 
0485 
0486 /*
0487  * NFSv4.0 and NFSv4.1 XDR decode functions
0488  *
0489  * NFSv4.0 callback result types are defined in section 15 of RFC
0490  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
0491  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
0492  * Protocol".
0493  */
0494 
0495 static int nfs4_xdr_dec_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
0496                 void *__unused)
0497 {
0498     return 0;
0499 }
0500 
0501 /*
0502  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
0503  */
0504 static int nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp,
0505                   struct xdr_stream *xdr,
0506                   void *data)
0507 {
0508     struct nfsd4_callback *cb = data;
0509     struct nfs4_cb_compound_hdr hdr;
0510     int status;
0511 
0512     status = decode_cb_compound4res(xdr, &hdr);
0513     if (unlikely(status))
0514         return status;
0515 
0516     status = decode_cb_sequence4res(xdr, cb);
0517     if (unlikely(status || cb->cb_seq_status))
0518         return status;
0519 
0520     return decode_cb_op_status(xdr, OP_CB_RECALL, &cb->cb_status);
0521 }
0522 
0523 #ifdef CONFIG_NFSD_PNFS
0524 /*
0525  * CB_LAYOUTRECALL4args
0526  *
0527  *  struct layoutrecall_file4 {
0528  *      nfs_fh4         lor_fh;
0529  *      offset4         lor_offset;
0530  *      length4         lor_length;
0531  *      stateid4        lor_stateid;
0532  *  };
0533  *
0534  *  union layoutrecall4 switch(layoutrecall_type4 lor_recalltype) {
0535  *  case LAYOUTRECALL4_FILE:
0536  *      layoutrecall_file4 lor_layout;
0537  *  case LAYOUTRECALL4_FSID:
0538  *      fsid4              lor_fsid;
0539  *  case LAYOUTRECALL4_ALL:
0540  *      void;
0541  *  };
0542  *
0543  *  struct CB_LAYOUTRECALL4args {
0544  *      layouttype4             clora_type;
0545  *      layoutiomode4           clora_iomode;
0546  *      bool                    clora_changed;
0547  *      layoutrecall4           clora_recall;
0548  *  };
0549  */
0550 static void encode_cb_layout4args(struct xdr_stream *xdr,
0551                   const struct nfs4_layout_stateid *ls,
0552                   struct nfs4_cb_compound_hdr *hdr)
0553 {
0554     __be32 *p;
0555 
0556     BUG_ON(hdr->minorversion == 0);
0557 
0558     p = xdr_reserve_space(xdr, 5 * 4);
0559     *p++ = cpu_to_be32(OP_CB_LAYOUTRECALL);
0560     *p++ = cpu_to_be32(ls->ls_layout_type);
0561     *p++ = cpu_to_be32(IOMODE_ANY);
0562     *p++ = cpu_to_be32(1);
0563     *p = cpu_to_be32(RETURN_FILE);
0564 
0565     encode_nfs_fh4(xdr, &ls->ls_stid.sc_file->fi_fhandle);
0566 
0567     p = xdr_reserve_space(xdr, 2 * 8);
0568     p = xdr_encode_hyper(p, 0);
0569     xdr_encode_hyper(p, NFS4_MAX_UINT64);
0570 
0571     encode_stateid4(xdr, &ls->ls_recall_sid);
0572 
0573     hdr->nops++;
0574 }
0575 
0576 static void nfs4_xdr_enc_cb_layout(struct rpc_rqst *req,
0577                    struct xdr_stream *xdr,
0578                    const void *data)
0579 {
0580     const struct nfsd4_callback *cb = data;
0581     const struct nfs4_layout_stateid *ls =
0582         container_of(cb, struct nfs4_layout_stateid, ls_recall);
0583     struct nfs4_cb_compound_hdr hdr = {
0584         .ident = 0,
0585         .minorversion = cb->cb_clp->cl_minorversion,
0586     };
0587 
0588     encode_cb_compound4args(xdr, &hdr);
0589     encode_cb_sequence4args(xdr, cb, &hdr);
0590     encode_cb_layout4args(xdr, ls, &hdr);
0591     encode_cb_nops(&hdr);
0592 }
0593 
0594 static int nfs4_xdr_dec_cb_layout(struct rpc_rqst *rqstp,
0595                   struct xdr_stream *xdr,
0596                   void *data)
0597 {
0598     struct nfsd4_callback *cb = data;
0599     struct nfs4_cb_compound_hdr hdr;
0600     int status;
0601 
0602     status = decode_cb_compound4res(xdr, &hdr);
0603     if (unlikely(status))
0604         return status;
0605 
0606     status = decode_cb_sequence4res(xdr, cb);
0607     if (unlikely(status || cb->cb_seq_status))
0608         return status;
0609 
0610     return decode_cb_op_status(xdr, OP_CB_LAYOUTRECALL, &cb->cb_status);
0611 }
0612 #endif /* CONFIG_NFSD_PNFS */
0613 
0614 static void encode_stateowner(struct xdr_stream *xdr, struct nfs4_stateowner *so)
0615 {
0616     __be32  *p;
0617 
0618     p = xdr_reserve_space(xdr, 8 + 4 + so->so_owner.len);
0619     p = xdr_encode_opaque_fixed(p, &so->so_client->cl_clientid, 8);
0620     xdr_encode_opaque(p, so->so_owner.data, so->so_owner.len);
0621 }
0622 
0623 static void nfs4_xdr_enc_cb_notify_lock(struct rpc_rqst *req,
0624                     struct xdr_stream *xdr,
0625                     const void *data)
0626 {
0627     const struct nfsd4_callback *cb = data;
0628     const struct nfsd4_blocked_lock *nbl =
0629         container_of(cb, struct nfsd4_blocked_lock, nbl_cb);
0630     struct nfs4_lockowner *lo = (struct nfs4_lockowner *)nbl->nbl_lock.fl_owner;
0631     struct nfs4_cb_compound_hdr hdr = {
0632         .ident = 0,
0633         .minorversion = cb->cb_clp->cl_minorversion,
0634     };
0635 
0636     __be32 *p;
0637 
0638     BUG_ON(hdr.minorversion == 0);
0639 
0640     encode_cb_compound4args(xdr, &hdr);
0641     encode_cb_sequence4args(xdr, cb, &hdr);
0642 
0643     p = xdr_reserve_space(xdr, 4);
0644     *p = cpu_to_be32(OP_CB_NOTIFY_LOCK);
0645     encode_nfs_fh4(xdr, &nbl->nbl_fh);
0646     encode_stateowner(xdr, &lo->lo_owner);
0647     hdr.nops++;
0648 
0649     encode_cb_nops(&hdr);
0650 }
0651 
0652 static int nfs4_xdr_dec_cb_notify_lock(struct rpc_rqst *rqstp,
0653                     struct xdr_stream *xdr,
0654                     void *data)
0655 {
0656     struct nfsd4_callback *cb = data;
0657     struct nfs4_cb_compound_hdr hdr;
0658     int status;
0659 
0660     status = decode_cb_compound4res(xdr, &hdr);
0661     if (unlikely(status))
0662         return status;
0663 
0664     status = decode_cb_sequence4res(xdr, cb);
0665     if (unlikely(status || cb->cb_seq_status))
0666         return status;
0667 
0668     return decode_cb_op_status(xdr, OP_CB_NOTIFY_LOCK, &cb->cb_status);
0669 }
0670 
0671 /*
0672  * struct write_response4 {
0673  *  stateid4    wr_callback_id<1>;
0674  *  length4     wr_count;
0675  *  stable_how4 wr_committed;
0676  *  verifier4   wr_writeverf;
0677  * };
0678  * union offload_info4 switch (nfsstat4 coa_status) {
0679  *  case NFS4_OK:
0680  *      write_response4 coa_resok4;
0681  *  default:
0682  *      length4     coa_bytes_copied;
0683  * };
0684  * struct CB_OFFLOAD4args {
0685  *  nfs_fh4     coa_fh;
0686  *  stateid4    coa_stateid;
0687  *  offload_info4   coa_offload_info;
0688  * };
0689  */
0690 static void encode_offload_info4(struct xdr_stream *xdr,
0691                  const struct nfsd4_cb_offload *cbo)
0692 {
0693     __be32 *p;
0694 
0695     p = xdr_reserve_space(xdr, 4);
0696     *p = cbo->co_nfserr;
0697     switch (cbo->co_nfserr) {
0698     case nfs_ok:
0699         p = xdr_reserve_space(xdr, 4 + 8 + 4 + NFS4_VERIFIER_SIZE);
0700         p = xdr_encode_empty_array(p);
0701         p = xdr_encode_hyper(p, cbo->co_res.wr_bytes_written);
0702         *p++ = cpu_to_be32(cbo->co_res.wr_stable_how);
0703         p = xdr_encode_opaque_fixed(p, cbo->co_res.wr_verifier.data,
0704                         NFS4_VERIFIER_SIZE);
0705         break;
0706     default:
0707         p = xdr_reserve_space(xdr, 8);
0708         /* We always return success if bytes were written */
0709         p = xdr_encode_hyper(p, 0);
0710     }
0711 }
0712 
0713 static void encode_cb_offload4args(struct xdr_stream *xdr,
0714                    const struct nfsd4_cb_offload *cbo,
0715                    struct nfs4_cb_compound_hdr *hdr)
0716 {
0717     __be32 *p;
0718 
0719     p = xdr_reserve_space(xdr, 4);
0720     *p = cpu_to_be32(OP_CB_OFFLOAD);
0721     encode_nfs_fh4(xdr, &cbo->co_fh);
0722     encode_stateid4(xdr, &cbo->co_res.cb_stateid);
0723     encode_offload_info4(xdr, cbo);
0724 
0725     hdr->nops++;
0726 }
0727 
0728 static void nfs4_xdr_enc_cb_offload(struct rpc_rqst *req,
0729                     struct xdr_stream *xdr,
0730                     const void *data)
0731 {
0732     const struct nfsd4_callback *cb = data;
0733     const struct nfsd4_cb_offload *cbo =
0734         container_of(cb, struct nfsd4_cb_offload, co_cb);
0735     struct nfs4_cb_compound_hdr hdr = {
0736         .ident = 0,
0737         .minorversion = cb->cb_clp->cl_minorversion,
0738     };
0739 
0740     encode_cb_compound4args(xdr, &hdr);
0741     encode_cb_sequence4args(xdr, cb, &hdr);
0742     encode_cb_offload4args(xdr, cbo, &hdr);
0743     encode_cb_nops(&hdr);
0744 }
0745 
0746 static int nfs4_xdr_dec_cb_offload(struct rpc_rqst *rqstp,
0747                    struct xdr_stream *xdr,
0748                    void *data)
0749 {
0750     struct nfsd4_callback *cb = data;
0751     struct nfs4_cb_compound_hdr hdr;
0752     int status;
0753 
0754     status = decode_cb_compound4res(xdr, &hdr);
0755     if (unlikely(status))
0756         return status;
0757 
0758     status = decode_cb_sequence4res(xdr, cb);
0759     if (unlikely(status || cb->cb_seq_status))
0760         return status;
0761 
0762     return decode_cb_op_status(xdr, OP_CB_OFFLOAD, &cb->cb_status);
0763 }
0764 /*
0765  * RPC procedure tables
0766  */
0767 #define PROC(proc, call, argtype, restype)              \
0768 [NFSPROC4_CLNT_##proc] = {                      \
0769     .p_proc    = NFSPROC4_CB_##call,                \
0770     .p_encode  = nfs4_xdr_enc_##argtype,        \
0771     .p_decode  = nfs4_xdr_dec_##restype,                \
0772     .p_arglen  = NFS4_enc_##argtype##_sz,               \
0773     .p_replen  = NFS4_dec_##restype##_sz,               \
0774     .p_statidx = NFSPROC4_CB_##call,                \
0775     .p_name    = #proc,                     \
0776 }
0777 
0778 static const struct rpc_procinfo nfs4_cb_procedures[] = {
0779     PROC(CB_NULL,   NULL,       cb_null,    cb_null),
0780     PROC(CB_RECALL, COMPOUND,   cb_recall,  cb_recall),
0781 #ifdef CONFIG_NFSD_PNFS
0782     PROC(CB_LAYOUT, COMPOUND,   cb_layout,  cb_layout),
0783 #endif
0784     PROC(CB_NOTIFY_LOCK,    COMPOUND,   cb_notify_lock, cb_notify_lock),
0785     PROC(CB_OFFLOAD,    COMPOUND,   cb_offload, cb_offload),
0786 };
0787 
0788 static unsigned int nfs4_cb_counts[ARRAY_SIZE(nfs4_cb_procedures)];
0789 static const struct rpc_version nfs_cb_version4 = {
0790 /*
0791  * Note on the callback rpc program version number: despite language in rfc
0792  * 5661 section 18.36.3 requiring servers to use 4 in this field, the
0793  * official xdr descriptions for both 4.0 and 4.1 specify version 1, and
0794  * in practice that appears to be what implementations use.  The section
0795  * 18.36.3 language is expected to be fixed in an erratum.
0796  */
0797     .number         = 1,
0798     .nrprocs        = ARRAY_SIZE(nfs4_cb_procedures),
0799     .procs          = nfs4_cb_procedures,
0800     .counts         = nfs4_cb_counts,
0801 };
0802 
0803 static const struct rpc_version *nfs_cb_version[2] = {
0804     [1] = &nfs_cb_version4,
0805 };
0806 
0807 static const struct rpc_program cb_program;
0808 
0809 static struct rpc_stat cb_stats = {
0810     .program        = &cb_program
0811 };
0812 
0813 #define NFS4_CALLBACK 0x40000000
0814 static const struct rpc_program cb_program = {
0815     .name           = "nfs4_cb",
0816     .number         = NFS4_CALLBACK,
0817     .nrvers         = ARRAY_SIZE(nfs_cb_version),
0818     .version        = nfs_cb_version,
0819     .stats          = &cb_stats,
0820     .pipe_dir_name      = "nfsd4_cb",
0821 };
0822 
0823 static int max_cb_time(struct net *net)
0824 {
0825     struct nfsd_net *nn = net_generic(net, nfsd_net_id);
0826 
0827     /*
0828      * nfsd4_lease is set to at most one hour in __nfsd4_write_time,
0829      * so we can use 32-bit math on it. Warn if that assumption
0830      * ever stops being true.
0831      */
0832     if (WARN_ON_ONCE(nn->nfsd4_lease > 3600))
0833         return 360 * HZ;
0834 
0835     return max(((u32)nn->nfsd4_lease)/10, 1u) * HZ;
0836 }
0837 
0838 static struct workqueue_struct *callback_wq;
0839 
0840 static bool nfsd4_queue_cb(struct nfsd4_callback *cb)
0841 {
0842     return queue_work(callback_wq, &cb->cb_work);
0843 }
0844 
0845 static void nfsd41_cb_inflight_begin(struct nfs4_client *clp)
0846 {
0847     atomic_inc(&clp->cl_cb_inflight);
0848 }
0849 
0850 static void nfsd41_cb_inflight_end(struct nfs4_client *clp)
0851 {
0852 
0853     if (atomic_dec_and_test(&clp->cl_cb_inflight))
0854         wake_up_var(&clp->cl_cb_inflight);
0855 }
0856 
0857 static void nfsd41_cb_inflight_wait_complete(struct nfs4_client *clp)
0858 {
0859     wait_var_event(&clp->cl_cb_inflight,
0860             !atomic_read(&clp->cl_cb_inflight));
0861 }
0862 
0863 static const struct cred *get_backchannel_cred(struct nfs4_client *clp, struct rpc_clnt *client, struct nfsd4_session *ses)
0864 {
0865     if (clp->cl_minorversion == 0) {
0866         client->cl_principal = clp->cl_cred.cr_targ_princ ?
0867             clp->cl_cred.cr_targ_princ : "nfs";
0868 
0869         return get_cred(rpc_machine_cred());
0870     } else {
0871         struct cred *kcred;
0872 
0873         kcred = prepare_kernel_cred(NULL);
0874         if (!kcred)
0875             return NULL;
0876 
0877         kcred->uid = ses->se_cb_sec.uid;
0878         kcred->gid = ses->se_cb_sec.gid;
0879         return kcred;
0880     }
0881 }
0882 
0883 static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn, struct nfsd4_session *ses)
0884 {
0885     int maxtime = max_cb_time(clp->net);
0886     struct rpc_timeout  timeparms = {
0887         .to_initval = maxtime,
0888         .to_retries = 0,
0889         .to_maxval  = maxtime,
0890     };
0891     struct rpc_create_args args = {
0892         .net        = clp->net,
0893         .address    = (struct sockaddr *) &conn->cb_addr,
0894         .addrsize   = conn->cb_addrlen,
0895         .saddress   = (struct sockaddr *) &conn->cb_saddr,
0896         .timeout    = &timeparms,
0897         .program    = &cb_program,
0898         .version    = 1,
0899         .flags      = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
0900         .cred       = current_cred(),
0901     };
0902     struct rpc_clnt *client;
0903     const struct cred *cred;
0904 
0905     if (clp->cl_minorversion == 0) {
0906         if (!clp->cl_cred.cr_principal &&
0907             (clp->cl_cred.cr_flavor >= RPC_AUTH_GSS_KRB5)) {
0908             trace_nfsd_cb_setup_err(clp, -EINVAL);
0909             return -EINVAL;
0910         }
0911         args.client_name = clp->cl_cred.cr_principal;
0912         args.prognumber = conn->cb_prog;
0913         args.protocol = XPRT_TRANSPORT_TCP;
0914         args.authflavor = clp->cl_cred.cr_flavor;
0915         clp->cl_cb_ident = conn->cb_ident;
0916     } else {
0917         if (!conn->cb_xprt)
0918             return -EINVAL;
0919         clp->cl_cb_conn.cb_xprt = conn->cb_xprt;
0920         clp->cl_cb_session = ses;
0921         args.bc_xprt = conn->cb_xprt;
0922         args.prognumber = clp->cl_cb_session->se_cb_prog;
0923         args.protocol = conn->cb_xprt->xpt_class->xcl_ident |
0924                 XPRT_TRANSPORT_BC;
0925         args.authflavor = ses->se_cb_sec.flavor;
0926     }
0927     /* Create RPC client */
0928     client = rpc_create(&args);
0929     if (IS_ERR(client)) {
0930         trace_nfsd_cb_setup_err(clp, PTR_ERR(client));
0931         return PTR_ERR(client);
0932     }
0933     cred = get_backchannel_cred(clp, client, ses);
0934     if (!cred) {
0935         trace_nfsd_cb_setup_err(clp, -ENOMEM);
0936         rpc_shutdown_client(client);
0937         return -ENOMEM;
0938     }
0939     clp->cl_cb_client = client;
0940     clp->cl_cb_cred = cred;
0941     rcu_read_lock();
0942     trace_nfsd_cb_setup(clp, rpc_peeraddr2str(client, RPC_DISPLAY_NETID),
0943                 args.authflavor);
0944     rcu_read_unlock();
0945     return 0;
0946 }
0947 
0948 static void nfsd4_mark_cb_state(struct nfs4_client *clp, int newstate)
0949 {
0950     if (clp->cl_cb_state != newstate) {
0951         clp->cl_cb_state = newstate;
0952         trace_nfsd_cb_state(clp);
0953     }
0954 }
0955 
0956 static void nfsd4_mark_cb_down(struct nfs4_client *clp, int reason)
0957 {
0958     if (test_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags))
0959         return;
0960     nfsd4_mark_cb_state(clp, NFSD4_CB_DOWN);
0961 }
0962 
0963 static void nfsd4_mark_cb_fault(struct nfs4_client *clp, int reason)
0964 {
0965     if (test_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags))
0966         return;
0967     nfsd4_mark_cb_state(clp, NFSD4_CB_FAULT);
0968 }
0969 
0970 static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
0971 {
0972     struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
0973 
0974     if (task->tk_status)
0975         nfsd4_mark_cb_down(clp, task->tk_status);
0976     else
0977         nfsd4_mark_cb_state(clp, NFSD4_CB_UP);
0978 }
0979 
0980 static void nfsd4_cb_probe_release(void *calldata)
0981 {
0982     struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
0983 
0984     nfsd41_cb_inflight_end(clp);
0985 
0986 }
0987 
0988 static const struct rpc_call_ops nfsd4_cb_probe_ops = {
0989     /* XXX: release method to ensure we set the cb channel down if
0990      * necessary on early failure? */
0991     .rpc_call_done = nfsd4_cb_probe_done,
0992     .rpc_release = nfsd4_cb_probe_release,
0993 };
0994 
0995 /*
0996  * Poke the callback thread to process any updates to the callback
0997  * parameters, and send a null probe.
0998  */
0999 void nfsd4_probe_callback(struct nfs4_client *clp)
1000 {
1001     trace_nfsd_cb_probe(clp);
1002     nfsd4_mark_cb_state(clp, NFSD4_CB_UNKNOWN);
1003     set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
1004     nfsd4_run_cb(&clp->cl_cb_null);
1005 }
1006 
1007 void nfsd4_probe_callback_sync(struct nfs4_client *clp)
1008 {
1009     nfsd4_probe_callback(clp);
1010     flush_workqueue(callback_wq);
1011 }
1012 
1013 void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *conn)
1014 {
1015     nfsd4_mark_cb_state(clp, NFSD4_CB_UNKNOWN);
1016     spin_lock(&clp->cl_lock);
1017     memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn));
1018     spin_unlock(&clp->cl_lock);
1019 }
1020 
1021 /*
1022  * There's currently a single callback channel slot.
1023  * If the slot is available, then mark it busy.  Otherwise, set the
1024  * thread for sleeping on the callback RPC wait queue.
1025  */
1026 static bool nfsd41_cb_get_slot(struct nfsd4_callback *cb, struct rpc_task *task)
1027 {
1028     struct nfs4_client *clp = cb->cb_clp;
1029 
1030     if (!cb->cb_holds_slot &&
1031         test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
1032         rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
1033         /* Race breaker */
1034         if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
1035             dprintk("%s slot is busy\n", __func__);
1036             return false;
1037         }
1038         rpc_wake_up_queued_task(&clp->cl_cb_waitq, task);
1039     }
1040     cb->cb_holds_slot = true;
1041     return true;
1042 }
1043 
1044 static void nfsd41_cb_release_slot(struct nfsd4_callback *cb)
1045 {
1046     struct nfs4_client *clp = cb->cb_clp;
1047 
1048     if (cb->cb_holds_slot) {
1049         cb->cb_holds_slot = false;
1050         clear_bit(0, &clp->cl_cb_slot_busy);
1051         rpc_wake_up_next(&clp->cl_cb_waitq);
1052     }
1053 }
1054 
1055 static void nfsd41_destroy_cb(struct nfsd4_callback *cb)
1056 {
1057     struct nfs4_client *clp = cb->cb_clp;
1058 
1059     nfsd41_cb_release_slot(cb);
1060     if (cb->cb_ops && cb->cb_ops->release)
1061         cb->cb_ops->release(cb);
1062     nfsd41_cb_inflight_end(clp);
1063 }
1064 
1065 /*
1066  * TODO: cb_sequence should support referring call lists, cachethis, multiple
1067  * slots, and mark callback channel down on communication errors.
1068  */
1069 static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
1070 {
1071     struct nfsd4_callback *cb = calldata;
1072     struct nfs4_client *clp = cb->cb_clp;
1073     u32 minorversion = clp->cl_minorversion;
1074 
1075     /*
1076      * cb_seq_status is only set in decode_cb_sequence4res,
1077      * and so will remain 1 if an rpc level failure occurs.
1078      */
1079     cb->cb_seq_status = 1;
1080     cb->cb_status = 0;
1081     if (minorversion && !nfsd41_cb_get_slot(cb, task))
1082         return;
1083     rpc_call_start(task);
1084 }
1085 
1086 static bool nfsd4_cb_sequence_done(struct rpc_task *task, struct nfsd4_callback *cb)
1087 {
1088     struct nfs4_client *clp = cb->cb_clp;
1089     struct nfsd4_session *session = clp->cl_cb_session;
1090     bool ret = true;
1091 
1092     if (!clp->cl_minorversion) {
1093         /*
1094          * If the backchannel connection was shut down while this
1095          * task was queued, we need to resubmit it after setting up
1096          * a new backchannel connection.
1097          *
1098          * Note that if we lost our callback connection permanently
1099          * the submission code will error out, so we don't need to
1100          * handle that case here.
1101          */
1102         if (RPC_SIGNALLED(task))
1103             goto need_restart;
1104 
1105         return true;
1106     }
1107 
1108     if (!cb->cb_holds_slot)
1109         goto need_restart;
1110 
1111     switch (cb->cb_seq_status) {
1112     case 0:
1113         /*
1114          * No need for lock, access serialized in nfsd4_cb_prepare
1115          *
1116          * RFC5661 20.9.3
1117          * If CB_SEQUENCE returns an error, then the state of the slot
1118          * (sequence ID, cached reply) MUST NOT change.
1119          */
1120         ++session->se_cb_seq_nr;
1121         break;
1122     case -ESERVERFAULT:
1123         ++session->se_cb_seq_nr;
1124         fallthrough;
1125     case 1:
1126     case -NFS4ERR_BADSESSION:
1127         nfsd4_mark_cb_fault(cb->cb_clp, cb->cb_seq_status);
1128         ret = false;
1129         break;
1130     case -NFS4ERR_DELAY:
1131         if (!rpc_restart_call(task))
1132             goto out;
1133 
1134         rpc_delay(task, 2 * HZ);
1135         return false;
1136     case -NFS4ERR_BADSLOT:
1137         goto retry_nowait;
1138     case -NFS4ERR_SEQ_MISORDERED:
1139         if (session->se_cb_seq_nr != 1) {
1140             session->se_cb_seq_nr = 1;
1141             goto retry_nowait;
1142         }
1143         break;
1144     default:
1145         nfsd4_mark_cb_fault(cb->cb_clp, cb->cb_seq_status);
1146         dprintk("%s: unprocessed error %d\n", __func__,
1147             cb->cb_seq_status);
1148     }
1149 
1150     nfsd41_cb_release_slot(cb);
1151     dprintk("%s: freed slot, new seqid=%d\n", __func__,
1152         clp->cl_cb_session->se_cb_seq_nr);
1153 
1154     if (RPC_SIGNALLED(task))
1155         goto need_restart;
1156 out:
1157     return ret;
1158 retry_nowait:
1159     if (rpc_restart_call_prepare(task))
1160         ret = false;
1161     goto out;
1162 need_restart:
1163     if (!test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags)) {
1164         task->tk_status = 0;
1165         cb->cb_need_restart = true;
1166     }
1167     return false;
1168 }
1169 
1170 static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
1171 {
1172     struct nfsd4_callback *cb = calldata;
1173     struct nfs4_client *clp = cb->cb_clp;
1174 
1175     if (!nfsd4_cb_sequence_done(task, cb))
1176         return;
1177 
1178     if (cb->cb_status) {
1179         WARN_ON_ONCE(task->tk_status);
1180         task->tk_status = cb->cb_status;
1181     }
1182 
1183     switch (cb->cb_ops->done(cb, task)) {
1184     case 0:
1185         task->tk_status = 0;
1186         rpc_restart_call_prepare(task);
1187         return;
1188     case 1:
1189         switch (task->tk_status) {
1190         case -EIO:
1191         case -ETIMEDOUT:
1192         case -EACCES:
1193             nfsd4_mark_cb_down(clp, task->tk_status);
1194         }
1195         break;
1196     default:
1197         BUG();
1198     }
1199 }
1200 
1201 static void nfsd4_cb_release(void *calldata)
1202 {
1203     struct nfsd4_callback *cb = calldata;
1204 
1205     if (cb->cb_need_restart)
1206         nfsd4_queue_cb(cb);
1207     else
1208         nfsd41_destroy_cb(cb);
1209 
1210 }
1211 
1212 static const struct rpc_call_ops nfsd4_cb_ops = {
1213     .rpc_call_prepare = nfsd4_cb_prepare,
1214     .rpc_call_done = nfsd4_cb_done,
1215     .rpc_release = nfsd4_cb_release,
1216 };
1217 
1218 int nfsd4_create_callback_queue(void)
1219 {
1220     callback_wq = alloc_ordered_workqueue("nfsd4_callbacks", 0);
1221     if (!callback_wq)
1222         return -ENOMEM;
1223     return 0;
1224 }
1225 
1226 void nfsd4_destroy_callback_queue(void)
1227 {
1228     destroy_workqueue(callback_wq);
1229 }
1230 
1231 /* must be called under the state lock */
1232 void nfsd4_shutdown_callback(struct nfs4_client *clp)
1233 {
1234     if (clp->cl_cb_state != NFSD4_CB_UNKNOWN)
1235         trace_nfsd_cb_shutdown(clp);
1236 
1237     set_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags);
1238     /*
1239      * Note this won't actually result in a null callback;
1240      * instead, nfsd4_run_cb_null() will detect the killed
1241      * client, destroy the rpc client, and stop:
1242      */
1243     nfsd4_run_cb(&clp->cl_cb_null);
1244     flush_workqueue(callback_wq);
1245     nfsd41_cb_inflight_wait_complete(clp);
1246 }
1247 
1248 /* requires cl_lock: */
1249 static struct nfsd4_conn * __nfsd4_find_backchannel(struct nfs4_client *clp)
1250 {
1251     struct nfsd4_session *s;
1252     struct nfsd4_conn *c;
1253 
1254     list_for_each_entry(s, &clp->cl_sessions, se_perclnt) {
1255         list_for_each_entry(c, &s->se_conns, cn_persession) {
1256             if (c->cn_flags & NFS4_CDFC4_BACK)
1257                 return c;
1258         }
1259     }
1260     return NULL;
1261 }
1262 
1263 /*
1264  * Note there isn't a lot of locking in this code; instead we depend on
1265  * the fact that it is run from the callback_wq, which won't run two
1266  * work items at once.  So, for example, callback_wq handles all access
1267  * of cl_cb_client and all calls to rpc_create or rpc_shutdown_client.
1268  */
1269 static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
1270 {
1271     struct nfs4_cb_conn conn;
1272     struct nfs4_client *clp = cb->cb_clp;
1273     struct nfsd4_session *ses = NULL;
1274     struct nfsd4_conn *c;
1275     int err;
1276 
1277     /*
1278      * This is either an update, or the client dying; in either case,
1279      * kill the old client:
1280      */
1281     if (clp->cl_cb_client) {
1282         rpc_shutdown_client(clp->cl_cb_client);
1283         clp->cl_cb_client = NULL;
1284         put_cred(clp->cl_cb_cred);
1285         clp->cl_cb_cred = NULL;
1286     }
1287     if (clp->cl_cb_conn.cb_xprt) {
1288         svc_xprt_put(clp->cl_cb_conn.cb_xprt);
1289         clp->cl_cb_conn.cb_xprt = NULL;
1290     }
1291     if (test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags))
1292         return;
1293     spin_lock(&clp->cl_lock);
1294     /*
1295      * Only serialized callback code is allowed to clear these
1296      * flags; main nfsd code can only set them:
1297      */
1298     BUG_ON(!(clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK));
1299     clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
1300     memcpy(&conn, &cb->cb_clp->cl_cb_conn, sizeof(struct nfs4_cb_conn));
1301     c = __nfsd4_find_backchannel(clp);
1302     if (c) {
1303         svc_xprt_get(c->cn_xprt);
1304         conn.cb_xprt = c->cn_xprt;
1305         ses = c->cn_session;
1306     }
1307     spin_unlock(&clp->cl_lock);
1308 
1309     err = setup_callback_client(clp, &conn, ses);
1310     if (err) {
1311         nfsd4_mark_cb_down(clp, err);
1312         if (c)
1313             svc_xprt_put(c->cn_xprt);
1314         return;
1315     }
1316 }
1317 
1318 static void
1319 nfsd4_run_cb_work(struct work_struct *work)
1320 {
1321     struct nfsd4_callback *cb =
1322         container_of(work, struct nfsd4_callback, cb_work);
1323     struct nfs4_client *clp = cb->cb_clp;
1324     struct rpc_clnt *clnt;
1325     int flags;
1326 
1327     if (cb->cb_need_restart) {
1328         cb->cb_need_restart = false;
1329     } else {
1330         if (cb->cb_ops && cb->cb_ops->prepare)
1331             cb->cb_ops->prepare(cb);
1332     }
1333 
1334     if (clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK)
1335         nfsd4_process_cb_update(cb);
1336 
1337     clnt = clp->cl_cb_client;
1338     if (!clnt) {
1339         /* Callback channel broken, or client killed; give up: */
1340         nfsd41_destroy_cb(cb);
1341         return;
1342     }
1343 
1344     /*
1345      * Don't send probe messages for 4.1 or later.
1346      */
1347     if (!cb->cb_ops && clp->cl_minorversion) {
1348         nfsd4_mark_cb_state(clp, NFSD4_CB_UP);
1349         nfsd41_destroy_cb(cb);
1350         return;
1351     }
1352 
1353     cb->cb_msg.rpc_cred = clp->cl_cb_cred;
1354     flags = clp->cl_minorversion ? RPC_TASK_NOCONNECT : RPC_TASK_SOFTCONN;
1355     rpc_call_async(clnt, &cb->cb_msg, RPC_TASK_SOFT | flags,
1356             cb->cb_ops ? &nfsd4_cb_ops : &nfsd4_cb_probe_ops, cb);
1357 }
1358 
1359 void nfsd4_init_cb(struct nfsd4_callback *cb, struct nfs4_client *clp,
1360         const struct nfsd4_callback_ops *ops, enum nfsd4_cb_op op)
1361 {
1362     cb->cb_clp = clp;
1363     cb->cb_msg.rpc_proc = &nfs4_cb_procedures[op];
1364     cb->cb_msg.rpc_argp = cb;
1365     cb->cb_msg.rpc_resp = cb;
1366     cb->cb_ops = ops;
1367     INIT_WORK(&cb->cb_work, nfsd4_run_cb_work);
1368     cb->cb_seq_status = 1;
1369     cb->cb_status = 0;
1370     cb->cb_need_restart = false;
1371     cb->cb_holds_slot = false;
1372 }
1373 
1374 void nfsd4_run_cb(struct nfsd4_callback *cb)
1375 {
1376     struct nfs4_client *clp = cb->cb_clp;
1377 
1378     nfsd41_cb_inflight_begin(clp);
1379     if (!nfsd4_queue_cb(cb))
1380         nfsd41_cb_inflight_end(clp);
1381 }
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