FreeBSD/Linux Kernel Cross Reference
sys/nfs/nfs_fha.h

     /*-
      * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
      *
      * Copyright (c) 2008 Isilon Inc http://www.isilon.com/
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     */
    /* $FreeBSD: releng/12.0/sys/nfs/nfs_fha.h 326272 2017-11-27 15:23:17Z pfg $ */
    
    #ifndef _NFS_FHA_H
    #define _NFS_FHA_H 1
    
    #ifdef  _KERNEL
    
    /* Sysctl defaults. */
    #define FHA_DEF_ENABLE                  1
    #define FHA_DEF_READ                    1
    #define FHA_DEF_WRITE                   1
    #define FHA_DEF_BIN_SHIFT               22 /* 4MB */
    #define FHA_DEF_MAX_NFSDS_PER_FH        8
    #define FHA_DEF_MAX_REQS_PER_NFSD       0  /* Unlimited */
    
    #define FHA_HASH_SIZE   251
    
    struct fha_ctls {
            int      enable;
            int      read;
            int      write;
            uint32_t bin_shift;
            uint32_t max_nfsds_per_fh;
            uint32_t max_reqs_per_nfsd;
    };
    
    /*
     * These are the entries in the filehandle hash.  They talk about a specific
     * file, requests against which are being handled by one or more nfsds.  We
     * keep a chain of nfsds against the file. We only have more than one if reads
     * are ongoing, and then only if the reads affect disparate regions of the
     * file.
     *
     * In general, we want to assign a new request to an existing nfsd if it is
     * going to contend with work happening already on that nfsd, or if the
     * operation is a read and the nfsd is already handling a proximate read.  We
     * do this to avoid jumping around in the read stream unnecessarily, and to
     * avoid contention between threads over single files.
     */
    struct fha_hash_entry {
            struct mtx *mtx;
            LIST_ENTRY(fha_hash_entry) link;
            u_int64_t fh;
            u_int32_t num_rw;
            u_int32_t num_exclusive;
            u_int8_t num_threads;
            struct svcthread_list threads;
    };
    
    LIST_HEAD(fha_hash_entry_list, fha_hash_entry);
    
    struct fha_hash_slot {
            struct fha_hash_entry_list list;
            struct mtx mtx;
    };
    
    /* A structure used for passing around data internally. */
    struct fha_info {
            u_int64_t fh;
            off_t offset;
            int locktype;
            int read;
            int write;
    };
    
    struct fha_callbacks {
            rpcproc_t (*get_procnum)(rpcproc_t procnum);
            int (*realign)(struct mbuf **mb, int malloc_flags);
            int (*get_fh)(uint64_t *fh, int v3, struct mbuf **md, caddr_t *dpos);
            int (*is_read)(rpcproc_t procnum);
            int (*is_write)(rpcproc_t procnum);
            int (*get_offset)(struct mbuf **md, caddr_t *dpos, int v3, struct
                              fha_info *info);
           int (*no_offset)(rpcproc_t procnum);
           void (*set_locktype)(rpcproc_t procnum, struct fha_info *info);
           int (*fhe_stats_sysctl)(SYSCTL_HANDLER_ARGS);
   };
   
   struct fha_params {
           struct fha_hash_slot fha_hash[FHA_HASH_SIZE];
           struct sysctl_ctx_list sysctl_ctx;
           struct sysctl_oid *sysctl_tree;
           struct fha_ctls ctls;
           struct fha_callbacks callbacks;
           char server_name[32];
           SVCPOOL **pool;
   };
   
   void fha_nd_complete(SVCTHREAD *, struct svc_req *);
   SVCTHREAD *fha_assign(SVCTHREAD *, struct svc_req *, struct fha_params *);
   void fha_init(struct fha_params *softc);
   void fha_uninit(struct fha_params *softc);
   int fhe_stats_sysctl(SYSCTL_HANDLER_ARGS, struct fha_params *softc);
   
   #endif /* _KERNEL */
   #endif /* _NFS_FHA_H_ */

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