/* * include/net/9p/client.h * * 9P Client Definitions * * Copyright (C) 2008 by Eric Van Hensbergen * Copyright (C) 2007 by Latchesar Ionkov * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 * as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to: * Free Software Foundation * 51 Franklin Street, Fifth Floor * Boston, MA 02111-1301 USA * */ #ifndef NET_9P_CLIENT_H #define NET_9P_CLIENT_H /* Number of requests per row */ #define P9_ROW_MAXTAG 255 /** * enum p9_trans_status - different states of underlying transports * @Connected: transport is connected and healthy * @Disconnected: transport has been disconnected * @Hung: transport is connected by wedged * * This enumeration details the various states a transport * instatiation can be in. */ enum p9_trans_status { Connected, Disconnected, Hung, }; /** * enum p9_req_status_t - virtio request status * @REQ_STATUS_IDLE: request slot unused * @REQ_STATUS_ALLOC: request has been allocated but not sent * @REQ_STATUS_UNSENT: request waiting to be sent * @REQ_STATUS_SENT: request sent to server * @REQ_STATUS_FLSH: a flush has been sent for this request * @REQ_STATUS_RCVD: response received from server * @REQ_STATUS_FLSHD: request has been flushed * @REQ_STATUS_ERROR: request encountered an error on the client side * * The @REQ_STATUS_IDLE state is used to mark a request slot as unused * but use is actually tracked by the idpool structure which handles tag * id allocation. * */ enum p9_req_status_t { REQ_STATUS_IDLE, REQ_STATUS_ALLOC, REQ_STATUS_UNSENT, REQ_STATUS_SENT, REQ_STATUS_FLSH, REQ_STATUS_RCVD, REQ_STATUS_FLSHD, REQ_STATUS_ERROR, }; /** * struct p9_req_t - request slots * @status: status of this request slot * @t_err: transport error * @wq: wait_queue for the client to block on for this request * @tc: the request fcall structure * @rc: the response fcall structure * @aux: transport specific data (provided for trans_fd migration) * @tag: tag on request (BUG: redundant) * @req_list: link for higher level objects to chain requests * * Transport use an array to track outstanding requests * instead of a list. While this may incurr overhead during initial * allocation or expansion, it makes request lookup much easier as the * tag id is a index into an array. (We use tag+1 so that we can accomodate * the -1 tag for the T_VERSION request). * This also has the nice effect of only having to allocate wait_queues * once, instead of constantly allocating and freeing them. Its possible * other resources could benefit from this scheme as well. * */ struct p9_req_t { int status; int t_err; wait_queue_head_t *wq; struct p9_fcall *tc; struct p9_fcall *rc; u16 flush_tag; void *aux; int tag; struct list_head req_list; }; /** * struct p9_client - per client instance state * @lock: protect @fidlist * @msize: maximum data size negotiated by protocol * @dotu: extension flags negotiated by protocol * @trans_mod: module API instantiated with this client * @trans: tranport instance state and API * @conn: connection state information used by trans_fd * @fidpool: fid handle accounting for session * @fidlist: List of active fid handles * @tagpool - transaction id accounting for session * @reqs - 2D array of requests * @max_tag - current maximum tag id allocated * * The client structure is used to keep track of various per-client * state that has been instantiated. * In order to minimize per-transaction overhead we use a * simple array to lookup requests instead of a hash table * or linked list. In order to support larger number of * transactions, we make this a 2D array, allocating new rows * when we need to grow the total number of the transactions. * * Each row is 256 requests and we'll support up to 256 rows for * a total of 64k concurrent requests per session. * * Bugs: duplicated data and potentially unnecessary elements. */ struct p9_client { spinlock_t lock; /* protect client structure */ int msize; unsigned char dotu; struct p9_trans_module *trans_mod; enum p9_trans_status status; void *trans; struct p9_conn *conn; struct p9_idpool *fidpool; struct list_head fidlist; struct p9_idpool *tagpool; struct p9_req_t *reqs[P9_ROW_MAXTAG]; int max_tag; }; /** * struct p9_fid - file system entity handle * @clnt: back pointer to instantiating &p9_client * @fid: numeric identifier for this handle * @mode: current mode of this fid (enum?) * @qid: the &p9_qid server identifier this handle points to * @iounit: the server reported maximum transaction size for this file * @uid: the numeric uid of the local user who owns this handle * @aux: transport specific information (unused?) * @rdir_fpos: tracks offset of file position when reading directory contents * @rdir_pos: (unused?) * @rdir_fcall: holds response of last directory read request * @flist: per-client-instance fid tracking * @dlist: per-dentry fid tracking * * TODO: This needs lots of explanation. */ struct p9_fid { struct p9_client *clnt; u32 fid; int mode; struct p9_qid qid; u32 iounit; uid_t uid; void *aux; int rdir_fpos; int rdir_pos; struct p9_fcall *rdir_fcall; struct list_head flist; struct list_head dlist; /* list of all fids attached to a dentry */ }; struct p9_client *p9_client_create(const char *dev_name, char *options); void p9_client_destroy(struct p9_client *clnt); void p9_client_disconnect(struct p9_client *clnt); struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid, char *uname, u32 n_uname, char *aname); struct p9_fid *p9_client_auth(struct p9_client *clnt, char *uname, u32 n_uname, char *aname); struct p9_fid *p9_client_walk(struct p9_fid *oldfid, int nwname, char **wnames, int clone); int p9_client_open(struct p9_fid *fid, int mode); int p9_client_fcreate(struct p9_fid *fid, char *name, u32 perm, int mode, char *extension); int p9_client_clunk(struct p9_fid *fid); int p9_client_remove(struct p9_fid *fid); int p9_client_read(struct p9_fid *fid, char *data, char __user *udata, u64 offset, u32 count); int p9_client_write(struct p9_fid *fid, char *data, const char __user *udata, u64 offset, u32 count); struct p9_stat *p9_client_stat(struct p9_fid *fid); int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst); struct p9_stat *p9_client_dirread(struct p9_fid *fid, u64 offset); struct p9_req_t *p9_tag_lookup(struct p9_client *, u16); void p9_client_cb(struct p9_client *c, struct p9_req_t *req); #endif /* NET_9P_CLIENT_H */