include/net/9p/client.h

   1 /*
   2  * include/net/9p/client.h
   3  *
   4  * 9P Client Definitions
   5  *
   6  *  Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
   7  *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
   8  *
   9  *  This program is free software; you can redistribute it and/or modify
  10  *  it under the terms of the GNU General Public License version 2
  11  *  as published by the Free Software Foundation.
  12  *
  13  *  This program is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *  GNU General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU General Public License
  19  *  along with this program; if not, write to:
  20  *  Free Software Foundation
  21  *  51 Franklin Street, Fifth Floor
  22  *  Boston, MA  02111-1301  USA
  23  *
  24  */
  25
  26 #ifndef NET_9P_CLIENT_H
  27 #define NET_9P_CLIENT_H
  28
  29 #include <linux/utsname.h>
  30
  31 /* Number of requests per row */
  32 #define P9_ROW_MAXTAG 255
  33
  34 /** enum p9_proto_versions - 9P protocol versions
  35  * @p9_proto_legacy: 9P Legacy mode, pre-9P2000.u
  36  * @p9_proto_2000u: 9P2000.u extension
  37  * @p9_proto_2000L: 9P2000.L extension
  38  */
  39
  40 enum p9_proto_versions{
  41         p9_proto_legacy,
  42         p9_proto_2000u,
  43         p9_proto_2000L,
  44 };
  45
  46
  47 /**
  48  * enum p9_trans_status - different states of underlying transports
  49  * @Connected: transport is connected and healthy
  50  * @Disconnected: transport has been disconnected
  51  * @Hung: transport is connected by wedged
  52  *
  53  * This enumeration details the various states a transport
  54  * instatiation can be in.
  55  */
  56
  57 enum p9_trans_status {
  58         Connected,
  59         BeginDisconnect,
  60         Disconnected,
  61         Hung,
  62 };
  63
  64 /**
  65  * enum p9_req_status_t - status of a request
  66  * @REQ_STATUS_IDLE: request slot unused
  67  * @REQ_STATUS_ALLOC: request has been allocated but not sent
  68  * @REQ_STATUS_UNSENT: request waiting to be sent
  69  * @REQ_STATUS_SENT: request sent to server
  70  * @REQ_STATUS_RCVD: response received from server
  71  * @REQ_STATUS_FLSHD: request has been flushed
  72  * @REQ_STATUS_ERROR: request encountered an error on the client side
  73  *
  74  * The @REQ_STATUS_IDLE state is used to mark a request slot as unused
  75  * but use is actually tracked by the idpool structure which handles tag
  76  * id allocation.
  77  *
  78  */
  79
  80 enum p9_req_status_t {
  81         REQ_STATUS_IDLE,
  82         REQ_STATUS_ALLOC,
  83         REQ_STATUS_UNSENT,
  84         REQ_STATUS_SENT,
  85         REQ_STATUS_RCVD,
  86         REQ_STATUS_FLSHD,
  87         REQ_STATUS_ERROR,
  88 };
  89
  90 /**
  91  * struct p9_req_t - request slots
  92  * @status: status of this request slot
  93  * @t_err: transport error
  94  * @flush_tag: tag of request being flushed (for flush requests)
  95  * @wq: wait_queue for the client to block on for this request
  96  * @tc: the request fcall structure
  97  * @rc: the response fcall structure
  98  * @aux: transport specific data (provided for trans_fd migration)
  99  * @req_list: link for higher level objects to chain requests
 100  *
 101  * Transport use an array to track outstanding requests
 102  * instead of a list.  While this may incurr overhead during initial
 103  * allocation or expansion, it makes request lookup much easier as the
 104  * tag id is a index into an array.  (We use tag+1 so that we can accommodate
 105  * the -1 tag for the T_VERSION request).
 106  * This also has the nice effect of only having to allocate wait_queues
 107  * once, instead of constantly allocating and freeing them.  Its possible
 108  * other resources could benefit from this scheme as well.
 109  *
 110  */
 111
 112 struct p9_req_t {
 113         int status;
 114         int t_err;
 115         wait_queue_head_t *wq;
 116         struct p9_fcall *tc;
 117         struct p9_fcall *rc;
 118         void *aux;
 119
 120         struct list_head req_list;
 121 };
 122
 123 /**
 124  * struct p9_client - per client instance state
 125  * @lock: protect @fidlist
 126  * @msize: maximum data size negotiated by protocol
 127  * @dotu: extension flags negotiated by protocol
 128  * @proto_version: 9P protocol version to use
 129  * @trans_mod: module API instantiated with this client
 130  * @trans: tranport instance state and API
 131  * @fidpool: fid handle accounting for session
 132  * @fidlist: List of active fid handles
 133  * @tagpool - transaction id accounting for session
 134  * @reqs - 2D array of requests
 135  * @max_tag - current maximum tag id allocated
 136  * @name - node name used as client id
 137  *
 138  * The client structure is used to keep track of various per-client
 139  * state that has been instantiated.
 140  * In order to minimize per-transaction overhead we use a
 141  * simple array to lookup requests instead of a hash table
 142  * or linked list.  In order to support larger number of
 143  * transactions, we make this a 2D array, allocating new rows
 144  * when we need to grow the total number of the transactions.
 145  *
 146  * Each row is 256 requests and we'll support up to 256 rows for
 147  * a total of 64k concurrent requests per session.
 148  *
 149  * Bugs: duplicated data and potentially unnecessary elements.
 150  */
 151
 152 struct p9_client {
 153         spinlock_t lock; /* protect client structure */
 154         unsigned int msize;
 155         unsigned char proto_version;
 156         struct p9_trans_module *trans_mod;
 157         enum p9_trans_status status;
 158         void *trans;
 159
 160         struct p9_idpool *fidpool;
 161         struct list_head fidlist;
 162
 163         struct p9_idpool *tagpool;
 164         struct p9_req_t *reqs[P9_ROW_MAXTAG];
 165         int max_tag;
 166
 167         char name[__NEW_UTS_LEN + 1];
 168 };
 169
 170 /**
 171  * struct p9_fid - file system entity handle
 172  * @clnt: back pointer to instantiating &p9_client
 173  * @fid: numeric identifier for this handle
 174  * @mode: current mode of this fid (enum?)
 175  * @qid: the &p9_qid server identifier this handle points to
 176  * @iounit: the server reported maximum transaction size for this file
 177  * @uid: the numeric uid of the local user who owns this handle
 178  * @rdir: readdir accounting structure (allocated on demand)
 179  * @flist: per-client-instance fid tracking
 180  * @dlist: per-dentry fid tracking
 181  *
 182  * TODO: This needs lots of explanation.
 183  */
 184
 185 struct p9_fid {
 186         struct p9_client *clnt;
 187         u32 fid;
 188         int mode;
 189         struct p9_qid qid;
 190         u32 iounit;
 191         kuid_t uid;
 192
 193         void *rdir;
 194
 195         struct list_head flist;
 196         struct hlist_node dlist;        /* list of all fids attached to a dentry */
 197 };
 198
 199 /**
 200  * struct p9_dirent - directory entry structure
 201  * @qid: The p9 server qid for this dirent
 202  * @d_off: offset to the next dirent
 203  * @d_type: type of file
 204  * @d_name: file name
 205  */
 206
 207 struct p9_dirent {
 208         struct p9_qid qid;
 209         u64 d_off;
 210         unsigned char d_type;
 211         char d_name[256];
 212 };
 213
 214 struct iov_iter;
 215
 216 int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb);
 217 int p9_client_rename(struct p9_fid *fid, struct p9_fid *newdirfid,
 218                      const char *name);
 219 int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
 220                        struct p9_fid *newdirfid, const char *new_name);
 221 struct p9_client *p9_client_create(const char *dev_name, char *options);
 222 void p9_client_destroy(struct p9_client *clnt);
 223 void p9_client_disconnect(struct p9_client *clnt);
 224 void p9_client_begin_disconnect(struct p9_client *clnt);
 225 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
 226                                 char *uname, kuid_t n_uname, char *aname);
 227 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
 228                 char **wnames, int clone);
 229 int p9_client_open(struct p9_fid *fid, int mode);
 230 int p9_client_fcreate(struct p9_fid *fid, char *name, u32 perm, int mode,
 231                                                         char *extension);
 232 int p9_client_link(struct p9_fid *fid, struct p9_fid *oldfid, char *newname);
 233 int p9_client_symlink(struct p9_fid *fid, char *name, char *symname, kgid_t gid,
 234                                                         struct p9_qid *qid);
 235 int p9_client_create_dotl(struct p9_fid *ofid, char *name, u32 flags, u32 mode,
 236                 kgid_t gid, struct p9_qid *qid);
 237 int p9_client_clunk(struct p9_fid *fid);
 238 int p9_client_fsync(struct p9_fid *fid, int datasync);
 239 int p9_client_remove(struct p9_fid *fid);
 240 int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags);
 241 int p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err);
 242 int p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err);
 243 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset);
 244 int p9dirent_read(struct p9_client *clnt, char *buf, int len,
 245                   struct p9_dirent *dirent);
 246 struct p9_wstat *p9_client_stat(struct p9_fid *fid);
 247 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst);
 248 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *attr);
 249
 250 struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
 251                                                         u64 request_mask);
 252
 253 int p9_client_mknod_dotl(struct p9_fid *oldfid, char *name, int mode,
 254                         dev_t rdev, kgid_t gid, struct p9_qid *);
 255 int p9_client_mkdir_dotl(struct p9_fid *fid, char *name, int mode,
 256                                 kgid_t gid, struct p9_qid *);
 257 int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status);
 258 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *fl);
 259 struct p9_req_t *p9_tag_lookup(struct p9_client *, u16);
 260 void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status);
 261
 262 int p9_parse_header(struct p9_fcall *, int32_t *, int8_t *, int16_t *, int);
 263 int p9stat_read(struct p9_client *, char *, int, struct p9_wstat *);
 264 void p9stat_free(struct p9_wstat *);
 265
 266 int p9_is_proto_dotu(struct p9_client *clnt);
 267 int p9_is_proto_dotl(struct p9_client *clnt);
 268 struct p9_fid *p9_client_xattrwalk(struct p9_fid *, const char *, u64 *);
 269 int p9_client_xattrcreate(struct p9_fid *, const char *, u64, int);
 270 int p9_client_readlink(struct p9_fid *fid, char **target);
 271
 272 #endif /* NET_9P_CLIENT_H */