xref: /linux/include/net/9p/client.h (revision 621cde16e49b3ecf7d59a8106a20aaebfb4a59a9)
1  /* SPDX-License-Identifier: GPL-2.0-only */
2  /*
3   * 9P Client Definitions
4   *
5   *  Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
6   *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
7   */
8  
9  #ifndef NET_9P_CLIENT_H
10  #define NET_9P_CLIENT_H
11  
12  #include <linux/utsname.h>
13  #include <linux/idr.h>
14  #include <linux/tracepoint-defs.h>
15  
16  /* Number of requests per row */
17  #define P9_ROW_MAXTAG 255
18  
19  /** enum p9_proto_versions - 9P protocol versions
20   * @p9_proto_legacy: 9P Legacy mode, pre-9P2000.u
21   * @p9_proto_2000u: 9P2000.u extension
22   * @p9_proto_2000L: 9P2000.L extension
23   */
24  
25  enum p9_proto_versions {
26  	p9_proto_legacy,
27  	p9_proto_2000u,
28  	p9_proto_2000L,
29  };
30  
31  
32  /**
33   * enum p9_trans_status - different states of underlying transports
34   * @Connected: transport is connected and healthy
35   * @Disconnected: transport has been disconnected
36   * @Hung: transport is connected by wedged
37   *
38   * This enumeration details the various states a transport
39   * instatiation can be in.
40   */
41  
42  enum p9_trans_status {
43  	Connected,
44  	BeginDisconnect,
45  	Disconnected,
46  	Hung,
47  };
48  
49  /**
50   * enum p9_req_status_t - status of a request
51   * @REQ_STATUS_ALLOC: request has been allocated but not sent
52   * @REQ_STATUS_UNSENT: request waiting to be sent
53   * @REQ_STATUS_SENT: request sent to server
54   * @REQ_STATUS_RCVD: response received from server
55   * @REQ_STATUS_FLSHD: request has been flushed
56   * @REQ_STATUS_ERROR: request encountered an error on the client side
57   */
58  
59  enum p9_req_status_t {
60  	REQ_STATUS_ALLOC,
61  	REQ_STATUS_UNSENT,
62  	REQ_STATUS_SENT,
63  	REQ_STATUS_RCVD,
64  	REQ_STATUS_FLSHD,
65  	REQ_STATUS_ERROR,
66  };
67  
68  /**
69   * struct p9_req_t - request slots
70   * @status: status of this request slot
71   * @t_err: transport error
72   * @wq: wait_queue for the client to block on for this request
73   * @tc: the request fcall structure
74   * @rc: the response fcall structure
75   * @req_list: link for higher level objects to chain requests
76   */
77  struct p9_req_t {
78  	int status;
79  	int t_err;
80  	refcount_t refcount;
81  	wait_queue_head_t wq;
82  	struct p9_fcall tc;
83  	struct p9_fcall rc;
84  	struct list_head req_list;
85  };
86  
87  /**
88   * struct p9_client - per client instance state
89   * @lock: protect @fids and @reqs
90   * @msize: maximum data size negotiated by protocol
91   * @proto_version: 9P protocol version to use
92   * @trans_mod: module API instantiated with this client
93   * @status: connection state
94   * @trans: tranport instance state and API
95   * @fids: All active FID handles
96   * @reqs: All active requests.
97   * @name: node name used as client id
98   *
99   * The client structure is used to keep track of various per-client
100   * state that has been instantiated.
101   */
102  struct p9_client {
103  	spinlock_t lock;
104  	unsigned int msize;
105  	unsigned char proto_version;
106  	struct p9_trans_module *trans_mod;
107  	enum p9_trans_status status;
108  	void *trans;
109  	struct kmem_cache *fcall_cache;
110  
111  	union {
112  		struct {
113  			int rfd;
114  			int wfd;
115  		} fd;
116  		struct {
117  			u16 port;
118  			bool privport;
119  
120  		} tcp;
121  	} trans_opts;
122  
123  	struct idr fids;
124  	struct idr reqs;
125  
126  	char name[__NEW_UTS_LEN + 1];
127  };
128  
129  /**
130   * struct p9_fid - file system entity handle
131   * @clnt: back pointer to instantiating &p9_client
132   * @fid: numeric identifier for this handle
133   * @mode: current mode of this fid (enum?)
134   * @qid: the &p9_qid server identifier this handle points to
135   * @iounit: the server reported maximum transaction size for this file
136   * @uid: the numeric uid of the local user who owns this handle
137   * @rdir: readdir accounting structure (allocated on demand)
138   * @dlist: per-dentry fid tracking
139   *
140   * TODO: This needs lots of explanation.
141   */
142  enum fid_source {
143  	FID_FROM_OTHER,
144  	FID_FROM_INODE,
145  	FID_FROM_DENTRY,
146  };
147  
148  struct p9_fid {
149  	struct p9_client *clnt;
150  	u32 fid;
151  	refcount_t count;
152  	int mode;
153  	struct p9_qid qid;
154  	u32 iounit;
155  	kuid_t uid;
156  
157  	void *rdir;
158  
159  	struct hlist_node dlist;	/* list of all fids attached to a dentry */
160  	struct hlist_node ilist;
161  };
162  
163  /**
164   * struct p9_dirent - directory entry structure
165   * @qid: The p9 server qid for this dirent
166   * @d_off: offset to the next dirent
167   * @d_type: type of file
168   * @d_name: file name
169   */
170  
171  struct p9_dirent {
172  	struct p9_qid qid;
173  	u64 d_off;
174  	unsigned char d_type;
175  	char d_name[256];
176  };
177  
178  struct iov_iter;
179  
180  int p9_show_client_options(struct seq_file *m, struct p9_client *clnt);
181  int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb);
182  int p9_client_rename(struct p9_fid *fid, struct p9_fid *newdirfid,
183  		     const char *name);
184  int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
185  		       struct p9_fid *newdirfid, const char *new_name);
186  struct p9_client *p9_client_create(const char *dev_name, char *options);
187  void p9_client_destroy(struct p9_client *clnt);
188  void p9_client_disconnect(struct p9_client *clnt);
189  void p9_client_begin_disconnect(struct p9_client *clnt);
190  struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
191  				const char *uname, kuid_t n_uname, const char *aname);
192  struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
193  		const unsigned char * const *wnames, int clone);
194  int p9_client_open(struct p9_fid *fid, int mode);
195  int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
196  							char *extension);
197  int p9_client_link(struct p9_fid *fid, struct p9_fid *oldfid, const char *newname);
198  int p9_client_symlink(struct p9_fid *fid, const char *name, const char *symname,
199  		kgid_t gid, struct p9_qid *qid);
200  int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags, u32 mode,
201  		kgid_t gid, struct p9_qid *qid);
202  int p9_client_clunk(struct p9_fid *fid);
203  int p9_client_fsync(struct p9_fid *fid, int datasync);
204  int p9_client_remove(struct p9_fid *fid);
205  int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags);
206  int p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err);
207  int p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
208  		int *err);
209  int p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err);
210  struct netfs_io_subrequest;
211  void p9_client_write_subreq(struct netfs_io_subrequest *subreq);
212  int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset);
213  int p9dirent_read(struct p9_client *clnt, char *buf, int len,
214  		  struct p9_dirent *dirent);
215  struct p9_wstat *p9_client_stat(struct p9_fid *fid);
216  int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst);
217  int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *attr);
218  
219  struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
220  							u64 request_mask);
221  
222  int p9_client_mknod_dotl(struct p9_fid *oldfid, const char *name, int mode,
223  			dev_t rdev, kgid_t gid, struct p9_qid *qid);
224  int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
225  				kgid_t gid, struct p9_qid *qid);
226  int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status);
227  int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *fl);
228  void p9_fcall_fini(struct p9_fcall *fc);
229  struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag);
230  
p9_req_get(struct p9_req_t * r)231  static inline void p9_req_get(struct p9_req_t *r)
232  {
233  	refcount_inc(&r->refcount);
234  }
235  
p9_req_try_get(struct p9_req_t * r)236  static inline int p9_req_try_get(struct p9_req_t *r)
237  {
238  	return refcount_inc_not_zero(&r->refcount);
239  }
240  
241  int p9_req_put(struct p9_client *c, struct p9_req_t *r);
242  
243  /* We cannot have the real tracepoints in header files,
244   * use a wrapper function */
245  DECLARE_TRACEPOINT(9p_fid_ref);
246  void do_trace_9p_fid_get(struct p9_fid *fid);
247  void do_trace_9p_fid_put(struct p9_fid *fid);
248  
249  /* fid reference counting helpers:
250   *  - fids used for any length of time should always be referenced through
251   *    p9_fid_get(), and released with p9_fid_put()
252   *  - v9fs_fid_lookup() or similar will automatically call get for you
253   *    and also require a put
254   *  - the *_fid_add() helpers will stash the fid in the inode,
255   *    at which point it is the responsibility of evict_inode()
256   *    to call the put
257   *  - the last put will automatically send a clunk to the server
258   */
p9_fid_get(struct p9_fid * fid)259  static inline struct p9_fid *p9_fid_get(struct p9_fid *fid)
260  {
261  	if (tracepoint_enabled(9p_fid_ref))
262  		do_trace_9p_fid_get(fid);
263  
264  	refcount_inc(&fid->count);
265  
266  	return fid;
267  }
268  
p9_fid_put(struct p9_fid * fid)269  static inline int p9_fid_put(struct p9_fid *fid)
270  {
271  	if (!fid || IS_ERR(fid))
272  		return 0;
273  
274  	if (tracepoint_enabled(9p_fid_ref))
275  		do_trace_9p_fid_put(fid);
276  
277  	if (!refcount_dec_and_test(&fid->count))
278  		return 0;
279  
280  	return p9_client_clunk(fid);
281  }
282  
283  void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status);
284  
285  int p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type,
286  		    int16_t *tag, int rewind);
287  int p9stat_read(struct p9_client *clnt, char *buf, int len,
288  		struct p9_wstat *st);
289  void p9stat_free(struct p9_wstat *stbuf);
290  
291  int p9_is_proto_dotu(struct p9_client *clnt);
292  int p9_is_proto_dotl(struct p9_client *clnt);
293  struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
294  				   const char *attr_name, u64 *attr_size);
295  int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
296  			  u64 attr_size, int flags);
297  int p9_client_readlink(struct p9_fid *fid, char **target);
298  
299  int p9_client_init(void);
300  void p9_client_exit(void);
301  
302  #endif /* NET_9P_CLIENT_H */
303