215 lines
6.9 KiB
C
215 lines
6.9 KiB
C
/*
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* include/net/9p/client.h
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*
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* 9P Client Definitions
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*
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* Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
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* Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to:
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* Free Software Foundation
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* 51 Franklin Street, Fifth Floor
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* Boston, MA 02111-1301 USA
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*
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*/
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#ifndef NET_9P_CLIENT_H
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#define NET_9P_CLIENT_H
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/* Number of requests per row */
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#define P9_ROW_MAXTAG 255
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/**
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* enum p9_trans_status - different states of underlying transports
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* @Connected: transport is connected and healthy
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* @Disconnected: transport has been disconnected
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* @Hung: transport is connected by wedged
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*
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* This enumeration details the various states a transport
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* instatiation can be in.
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*/
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enum p9_trans_status {
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Connected,
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Disconnected,
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Hung,
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};
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/**
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* enum p9_req_status_t - virtio request status
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* @REQ_STATUS_IDLE: request slot unused
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* @REQ_STATUS_ALLOC: request has been allocated but not sent
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* @REQ_STATUS_UNSENT: request waiting to be sent
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* @REQ_STATUS_SENT: request sent to server
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* @REQ_STATUS_FLSH: a flush has been sent for this request
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* @REQ_STATUS_RCVD: response received from server
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* @REQ_STATUS_FLSHD: request has been flushed
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* @REQ_STATUS_ERROR: request encountered an error on the client side
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*
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* The @REQ_STATUS_IDLE state is used to mark a request slot as unused
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* but use is actually tracked by the idpool structure which handles tag
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* id allocation.
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*
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*/
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enum p9_req_status_t {
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REQ_STATUS_IDLE,
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REQ_STATUS_ALLOC,
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REQ_STATUS_UNSENT,
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REQ_STATUS_SENT,
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REQ_STATUS_FLSH,
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REQ_STATUS_RCVD,
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REQ_STATUS_FLSHD,
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REQ_STATUS_ERROR,
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};
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/**
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* struct p9_req_t - request slots
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* @status: status of this request slot
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* @t_err: transport error
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* @flush_tag: tag of request being flushed (for flush requests)
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* @wq: wait_queue for the client to block on for this request
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* @tc: the request fcall structure
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* @rc: the response fcall structure
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* @aux: transport specific data (provided for trans_fd migration)
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* @req_list: link for higher level objects to chain requests
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*
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* Transport use an array to track outstanding requests
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* instead of a list. While this may incurr overhead during initial
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* allocation or expansion, it makes request lookup much easier as the
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* tag id is a index into an array. (We use tag+1 so that we can accomodate
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* the -1 tag for the T_VERSION request).
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* This also has the nice effect of only having to allocate wait_queues
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* once, instead of constantly allocating and freeing them. Its possible
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* other resources could benefit from this scheme as well.
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*
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*/
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struct p9_req_t {
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int status;
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int t_err;
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wait_queue_head_t *wq;
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struct p9_fcall *tc;
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struct p9_fcall *rc;
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void *aux;
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struct list_head req_list;
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};
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/**
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* struct p9_client - per client instance state
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* @lock: protect @fidlist
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* @msize: maximum data size negotiated by protocol
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* @dotu: extension flags negotiated by protocol
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* @trans_mod: module API instantiated with this client
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* @trans: tranport instance state and API
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* @conn: connection state information used by trans_fd
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* @fidpool: fid handle accounting for session
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* @fidlist: List of active fid handles
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* @tagpool - transaction id accounting for session
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* @reqs - 2D array of requests
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* @max_tag - current maximum tag id allocated
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*
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* The client structure is used to keep track of various per-client
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* state that has been instantiated.
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* In order to minimize per-transaction overhead we use a
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* simple array to lookup requests instead of a hash table
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* or linked list. In order to support larger number of
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* transactions, we make this a 2D array, allocating new rows
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* when we need to grow the total number of the transactions.
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*
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* Each row is 256 requests and we'll support up to 256 rows for
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* a total of 64k concurrent requests per session.
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*
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* Bugs: duplicated data and potentially unnecessary elements.
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*/
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struct p9_client {
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spinlock_t lock; /* protect client structure */
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int msize;
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unsigned char dotu;
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struct p9_trans_module *trans_mod;
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enum p9_trans_status status;
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void *trans;
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struct p9_conn *conn;
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struct p9_idpool *fidpool;
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struct list_head fidlist;
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struct p9_idpool *tagpool;
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struct p9_req_t *reqs[P9_ROW_MAXTAG];
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int max_tag;
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};
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/**
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* struct p9_fid - file system entity handle
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* @clnt: back pointer to instantiating &p9_client
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* @fid: numeric identifier for this handle
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* @mode: current mode of this fid (enum?)
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* @qid: the &p9_qid server identifier this handle points to
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* @iounit: the server reported maximum transaction size for this file
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* @uid: the numeric uid of the local user who owns this handle
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* @aux: transport specific information (unused?)
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* @rdir_fpos: tracks offset of file position when reading directory contents
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* @flist: per-client-instance fid tracking
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* @dlist: per-dentry fid tracking
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*
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* TODO: This needs lots of explanation.
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*/
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struct p9_fid {
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struct p9_client *clnt;
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u32 fid;
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int mode;
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struct p9_qid qid;
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u32 iounit;
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uid_t uid;
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void *aux;
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int rdir_fpos;
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struct list_head flist;
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struct list_head dlist; /* list of all fids attached to a dentry */
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};
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int p9_client_version(struct p9_client *);
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struct p9_client *p9_client_create(const char *dev_name, char *options);
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void p9_client_destroy(struct p9_client *clnt);
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void p9_client_disconnect(struct p9_client *clnt);
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struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
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char *uname, u32 n_uname, char *aname);
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struct p9_fid *p9_client_auth(struct p9_client *clnt, char *uname,
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u32 n_uname, char *aname);
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struct p9_fid *p9_client_walk(struct p9_fid *oldfid, int nwname, char **wnames,
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int clone);
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int p9_client_open(struct p9_fid *fid, int mode);
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int p9_client_fcreate(struct p9_fid *fid, char *name, u32 perm, int mode,
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char *extension);
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int p9_client_clunk(struct p9_fid *fid);
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int p9_client_remove(struct p9_fid *fid);
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int p9_client_read(struct p9_fid *fid, char *data, char __user *udata,
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u64 offset, u32 count);
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int p9_client_write(struct p9_fid *fid, char *data, const char __user *udata,
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u64 offset, u32 count);
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struct p9_wstat *p9_client_stat(struct p9_fid *fid);
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int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst);
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struct p9_req_t *p9_tag_lookup(struct p9_client *, u16);
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void p9_client_cb(struct p9_client *c, struct p9_req_t *req);
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int p9_parse_header(struct p9_fcall *, int32_t *, int8_t *, int16_t *, int);
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int p9stat_read(char *, int, struct p9_wstat *, int);
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void p9stat_free(struct p9_wstat *);
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#endif /* NET_9P_CLIENT_H */
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