fs/nfsd/localio.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * NFS server support for local clients to bypass network stack
   4  *
   5  * Copyright (C) 2014 Weston Andros Adamson <dros@primarydata.com>
   6  * Copyright (C) 2019 Trond Myklebust <trond.myklebust@hammerspace.com>
   7  * Copyright (C) 2024 Mike Snitzer <snitzer@hammerspace.com>
   8  * Copyright (C) 2024 NeilBrown <neilb@suse.de>
   9  */
  10
  11 #include <linux/exportfs.h>
  12 #include <linux/sunrpc/svcauth.h>
  13 #include <linux/sunrpc/clnt.h>
  14 #include <linux/nfs.h>
  15 #include <linux/nfs_common.h>
  16 #include <linux/nfslocalio.h>
  17 #include <linux/nfs_fs.h>
  18 #include <linux/nfs_xdr.h>
  19 #include <linux/string.h>
  20
  21 #include "nfsd.h"
  22 #include "vfs.h"
  23 #include "netns.h"
  24 #include "filecache.h"
  25 #include "cache.h"
  26
  27 static const struct nfsd_localio_operations nfsd_localio_ops = {
  28         .nfsd_net_try_get  = nfsd_net_try_get,
  29         .nfsd_net_put  = nfsd_net_put,
  30         .nfsd_open_local_fh = nfsd_open_local_fh,
  31         .nfsd_file_put_local = nfsd_file_put_local,
  32         .nfsd_file_get = nfsd_file_get,
  33         .nfsd_file_put = nfsd_file_put,
  34         .nfsd_file_file = nfsd_file_file,
  35 };
  36
  37 void nfsd_localio_ops_init(void)
  38 {
  39         nfs_to = &nfsd_localio_ops;
  40 }
  41
  42 /**
  43  * nfsd_open_local_fh - lookup a local filehandle @nfs_fh and map to nfsd_file
  44  *
  45  * @net: 'struct net' to get the proper nfsd_net required for LOCALIO access
  46  * @dom: 'struct auth_domain' required for LOCALIO access
  47  * @rpc_clnt: rpc_clnt that the client established
  48  * @cred: cred that the client established
  49  * @nfs_fh: filehandle to lookup
  50  * @fmode: fmode_t to use for open
  51  *
  52  * This function maps a local fh to a path on a local filesystem.
  53  * This is useful when the nfs client has the local server mounted - it can
  54  * avoid all the NFS overhead with reads, writes and commits.
  55  *
  56  * On successful return, returned nfsd_file will have its nf_net member
  57  * set. Caller (NFS client) is responsible for calling nfsd_net_put and
  58  * nfsd_file_put (via nfs_to_nfsd_file_put_local).
  59  */
  60 struct nfsd_file *
  61 nfsd_open_local_fh(struct net *net, struct auth_domain *dom,
  62                    struct rpc_clnt *rpc_clnt, const struct cred *cred,
  63                    const struct nfs_fh *nfs_fh, const fmode_t fmode)
  64 {
  65         int mayflags = NFSD_MAY_LOCALIO;
  66         struct svc_cred rq_cred;
  67         struct svc_fh fh;
  68         struct nfsd_file *localio;
  69         __be32 beres;
  70
  71         if (nfs_fh->size > NFS4_FHSIZE)
  72                 return ERR_PTR(-EINVAL);
  73
  74         /* nfs_fh -> svc_fh */
  75         fh_init(&fh, NFS4_FHSIZE);
  76         fh.fh_handle.fh_size = nfs_fh->size;
  77         memcpy(fh.fh_handle.fh_raw, nfs_fh->data, nfs_fh->size);
  78
  79         if (fmode & FMODE_READ)
  80                 mayflags |= NFSD_MAY_READ;
  81         if (fmode & FMODE_WRITE)
  82                 mayflags |= NFSD_MAY_WRITE;
  83
  84         svcauth_map_clnt_to_svc_cred_local(rpc_clnt, cred, &rq_cred);
  85
  86         beres = nfsd_file_acquire_local(net, &rq_cred, dom,
  87                                         &fh, mayflags, &localio);
  88         if (beres)
  89                 localio = ERR_PTR(nfs_stat_to_errno(be32_to_cpu(beres)));
  90
  91         fh_put(&fh);
  92         if (rq_cred.cr_group_info)
  93                 put_group_info(rq_cred.cr_group_info);
  94
  95         return localio;
  96 }
  97 EXPORT_SYMBOL_GPL(nfsd_open_local_fh);
  98
  99 /*
 100  * UUID_IS_LOCAL XDR functions
 101  */
 102
 103 static __be32 localio_proc_null(struct svc_rqst *rqstp)
 104 {
 105         return rpc_success;
 106 }
 107
 108 struct localio_uuidarg {
 109         uuid_t                  uuid;
 110 };
 111
 112 static __be32 localio_proc_uuid_is_local(struct svc_rqst *rqstp)
 113 {
 114         struct localio_uuidarg *argp = rqstp->rq_argp;
 115         struct net *net = SVC_NET(rqstp);
 116         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 117
 118         nfs_uuid_is_local(&argp->uuid, &nn->local_clients,
 119                           &nn->local_clients_lock,
 120                           net, rqstp->rq_client, THIS_MODULE);
 121
 122         return rpc_success;
 123 }
 124
 125 static bool localio_decode_uuidarg(struct svc_rqst *rqstp,
 126                                    struct xdr_stream *xdr)
 127 {
 128         struct localio_uuidarg *argp = rqstp->rq_argp;
 129         u8 uuid[UUID_SIZE];
 130
 131         if (decode_opaque_fixed(xdr, uuid, UUID_SIZE))
 132                 return false;
 133         import_uuid(&argp->uuid, uuid);
 134
 135         return true;
 136 }
 137
 138 static const struct svc_procedure localio_procedures1[] = {
 139         [LOCALIOPROC_NULL] = {
 140                 .pc_func = localio_proc_null,
 141                 .pc_decode = nfssvc_decode_voidarg,
 142                 .pc_encode = nfssvc_encode_voidres,
 143                 .pc_argsize = sizeof(struct nfsd_voidargs),
 144                 .pc_ressize = sizeof(struct nfsd_voidres),
 145                 .pc_cachetype = RC_NOCACHE,
 146                 .pc_xdrressize = 0,
 147                 .pc_name = "NULL",
 148         },
 149         [LOCALIOPROC_UUID_IS_LOCAL] = {
 150                 .pc_func = localio_proc_uuid_is_local,
 151                 .pc_decode = localio_decode_uuidarg,
 152                 .pc_encode = nfssvc_encode_voidres,
 153                 .pc_argsize = sizeof(struct localio_uuidarg),
 154                 .pc_argzero = sizeof(struct localio_uuidarg),
 155                 .pc_ressize = sizeof(struct nfsd_voidres),
 156                 .pc_cachetype = RC_NOCACHE,
 157                 .pc_name = "UUID_IS_LOCAL",
 158         },
 159 };
 160
 161 #define LOCALIO_NR_PROCEDURES ARRAY_SIZE(localio_procedures1)
 162 static DEFINE_PER_CPU_ALIGNED(unsigned long,
 163                               localio_count[LOCALIO_NR_PROCEDURES]);
 164 const struct svc_version localio_version1 = {
 165         .vs_vers        = 1,
 166         .vs_nproc       = LOCALIO_NR_PROCEDURES,
 167         .vs_proc        = localio_procedures1,
 168         .vs_dispatch    = nfsd_dispatch,
 169         .vs_count       = localio_count,
 170         .vs_xdrsize     = XDR_QUADLEN(UUID_SIZE),
 171         .vs_hidden      = true,
 172 };