client.h

  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/* DEFAULT MSIZE = 32 pages worth of payload + P9_HDRSZ +
 20 * room for write (16 extra) or read (11 extra) operands.
 21 */
 22
 23#define DEFAULT_MSIZE ((128 * 1024) + P9_IOHDRSZ)
 24
 25/** enum p9_proto_versions - 9P protocol versions
 26 * @p9_proto_legacy: 9P Legacy mode, pre-9P2000.u
 27 * @p9_proto_2000u: 9P2000.u extension
 28 * @p9_proto_2000L: 9P2000.L extension
 29 */
 30
 31enum p9_proto_versions {
 32	p9_proto_legacy,
 33	p9_proto_2000u,
 34	p9_proto_2000L,
 35};
 36
 37
 38/**
 39 * enum p9_trans_status - different states of underlying transports
 40 * @Connected: transport is connected and healthy
 41 * @Disconnected: transport has been disconnected
 42 * @Hung: transport is connected by wedged
 43 *
 44 * This enumeration details the various states a transport
 45 * instatiation can be in.
 46 */
 47
 48enum p9_trans_status {
 49	Connected,
 50	BeginDisconnect,
 51	Disconnected,
 52	Hung,
 53};
 54
 55/**
 56 * enum p9_req_status_t - status of a request
 57 * @REQ_STATUS_ALLOC: request has been allocated but not sent
 58 * @REQ_STATUS_UNSENT: request waiting to be sent
 59 * @REQ_STATUS_SENT: request sent to server
 60 * @REQ_STATUS_RCVD: response received from server
 61 * @REQ_STATUS_FLSHD: request has been flushed
 62 * @REQ_STATUS_ERROR: request encountered an error on the client side
 63 */
 64
 65enum p9_req_status_t {
 66	REQ_STATUS_ALLOC,
 67	REQ_STATUS_UNSENT,
 68	REQ_STATUS_SENT,
 69	REQ_STATUS_RCVD,
 70	REQ_STATUS_FLSHD,
 71	REQ_STATUS_ERROR,
 72};
 73
 74/**
 75 * struct p9_req_t - request slots
 76 * @status: status of this request slot
 77 * @t_err: transport error
 78 * @wq: wait_queue for the client to block on for this request
 79 * @tc: the request fcall structure
 80 * @rc: the response fcall structure
 81 * @req_list: link for higher level objects to chain requests
 82 */
 83struct p9_req_t {
 84	int status;
 85	int t_err;
 86	refcount_t refcount;
 87	wait_queue_head_t wq;
 88	struct p9_fcall tc;
 89	struct p9_fcall rc;
 90	struct list_head req_list;
 91};
 92
 93/**
 94 * struct p9_client - per client instance state
 95 * @lock: protect @fids and @reqs
 96 * @msize: maximum data size negotiated by protocol
 97 * @proto_version: 9P protocol version to use
 98 * @trans_mod: module API instantiated with this client
 99 * @status: connection state
100 * @trans: tranport instance state and API
101 * @fids: All active FID handles
102 * @reqs: All active requests.
103 * @name: node name used as client id
104 *
105 * The client structure is used to keep track of various per-client
106 * state that has been instantiated.
107 */
108struct p9_client {
109	spinlock_t lock;
110	unsigned int msize;
111	unsigned char proto_version;
112	struct p9_trans_module *trans_mod;
113	enum p9_trans_status status;
114	void *trans;
115	struct kmem_cache *fcall_cache;
116
117	union {
118		struct {
119			int rfd;
120			int wfd;
121		} fd;
122		struct {
123			u16 port;
124			bool privport;
125
126		} tcp;
127	} trans_opts;
128
129	struct idr fids;
130	struct idr reqs;
131
132	char name[__NEW_UTS_LEN + 1];
133};
134
135/**
136 * struct p9_fd_opts - holds client options during parsing
137 * @msize: maximum data size negotiated by protocol
138 * @prot-Oversion: 9P protocol version to use
139 * @trans_mod: module API instantiated with this client
140 *
141 * These parsed options get transferred into client in
142 * apply_client_options()
143 */
144struct p9_client_opts {
145	unsigned int msize;
146	unsigned char proto_version;
147	struct p9_trans_module *trans_mod;
148};
149
150/**
151 * struct p9_fd_opts - per-transport options for fd transport
152 * @rfd: file descriptor for reading (trans=fd)
153 * @wfd: file descriptor for writing (trans=fd)
154 * @port: port to connect to (trans=tcp)
155 * @privport: port is privileged
156 */
157struct p9_fd_opts {
158	int rfd;
159	int wfd;
160	u16 port;
161	bool privport;
162};
163
164/**
165 * struct p9_rdma_opts - Collection of mount options for rdma transport
166 * @port: port of connection
167 * @privport: Whether a privileged port may be used
168 * @sq_depth: The requested depth of the SQ. This really doesn't need
169 * to be any deeper than the number of threads used in the client
170 * @rq_depth: The depth of the RQ. Should be greater than or equal to SQ depth
171 * @timeout: Time to wait in msecs for CM events
172 */
173struct p9_rdma_opts {
174	short port;
175	bool privport;
176	int sq_depth;
177	int rq_depth;
178	long timeout;
179};
180
181/**
182 * struct p9_session_opts - holds parsed options for v9fs_session_info
183 * @flags: session options of type &p9_session_flags
184 * @nodev: set to 1 to disable device mapping
185 * @debug: debug level
186 * @afid: authentication handle
187 * @cache: cache mode of type &p9_cache_bits
188 * @cachetag: the tag of the cache associated with this session
189 * @uname: string user name to mount hierarchy as
190 * @aname: mount specifier for remote hierarchy
191 * @dfltuid: default numeric userid to mount hierarchy as
192 * @dfltgid: default numeric groupid to mount hierarchy as
193 * @uid: if %V9FS_ACCESS_SINGLE, the numeric uid which mounted the hierarchy
194 * @session_lock_timeout: retry interval for blocking locks
195 *
196 * This strucure holds options which are parsed and will be transferred
197 * to the v9fs_session_info structure when mounted, and therefore largely
198 * duplicates struct v9fs_session_info.
199 */
200struct p9_session_opts {
201	unsigned int flags;
202	unsigned char nodev;
203	unsigned short debug;
204	unsigned int afid;
205	unsigned int cache;
206#ifdef CONFIG_9P_FSCACHE
207	char *cachetag;
208#endif
209	char *uname;
210	char *aname;
211	kuid_t dfltuid;
212	kgid_t dfltgid;
213	kuid_t uid;
214	long session_lock_timeout;
215};
216
217/* Used by mount API to store parsed mount options */
218struct v9fs_context {
219	struct p9_client_opts	client_opts;
220	struct p9_fd_opts	fd_opts;
221	struct p9_rdma_opts	rdma_opts;
222	struct p9_session_opts	session_opts;
223};
224
225/**
226 * struct p9_fid - file system entity handle
227 * @clnt: back pointer to instantiating &p9_client
228 * @fid: numeric identifier for this handle
229 * @mode: current mode of this fid (enum?)
230 * @qid: the &p9_qid server identifier this handle points to
231 * @iounit: the server reported maximum transaction size for this file
232 * @uid: the numeric uid of the local user who owns this handle
233 * @rdir: readdir accounting structure (allocated on demand)
234 * @dlist: per-dentry fid tracking
235 *
236 * TODO: This needs lots of explanation.
237 */
238enum fid_source {
239	FID_FROM_OTHER,
240	FID_FROM_INODE,
241	FID_FROM_DENTRY,
242};
243
244struct p9_fid {
245	struct p9_client *clnt;
246	u32 fid;
247	refcount_t count;
248	int mode;
249	struct p9_qid qid;
250	u32 iounit;
251	kuid_t uid;
252
253	void *rdir;
254
255	struct hlist_node dlist;	/* list of all fids attached to a dentry */
256	struct hlist_node ilist;
257};
258
259/**
260 * struct p9_dirent - directory entry structure
261 * @qid: The p9 server qid for this dirent
262 * @d_off: offset to the next dirent
263 * @d_type: type of file
264 * @d_name: file name
265 */
266
267struct p9_dirent {
268	struct p9_qid qid;
269	u64 d_off;
270	unsigned char d_type;
271	char d_name[256];
272};
273
274struct iov_iter;
275
276int p9_show_client_options(struct seq_file *m, struct p9_client *clnt);
277int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb);
278int p9_client_rename(struct p9_fid *fid, struct p9_fid *newdirfid,
279		     const char *name);
280int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
281		       struct p9_fid *newdirfid, const char *new_name);
282struct p9_client *p9_client_create(struct fs_context *fc);
283void p9_client_destroy(struct p9_client *clnt);
284void p9_client_disconnect(struct p9_client *clnt);
285void p9_client_begin_disconnect(struct p9_client *clnt);
286struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
287				const char *uname, kuid_t n_uname, const char *aname);
288struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
289		const unsigned char * const *wnames, int clone);
290int p9_client_open(struct p9_fid *fid, int mode);
291int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
292							char *extension);
293int p9_client_link(struct p9_fid *fid, struct p9_fid *oldfid, const char *newname);
294int p9_client_symlink(struct p9_fid *fid, const char *name, const char *symname,
295		kgid_t gid, struct p9_qid *qid);
296int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags, u32 mode,
297		kgid_t gid, struct p9_qid *qid);
298int p9_client_clunk(struct p9_fid *fid);
299int p9_client_fsync(struct p9_fid *fid, int datasync);
300int p9_client_remove(struct p9_fid *fid);
301int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags);
302int p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err);
303int p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
304		int *err);
305int p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err);
306struct netfs_io_subrequest;
307void p9_client_write_subreq(struct netfs_io_subrequest *subreq);
308int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset);
309int p9dirent_read(struct p9_client *clnt, char *buf, int len,
310		  struct p9_dirent *dirent);
311struct p9_wstat *p9_client_stat(struct p9_fid *fid);
312int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst);
313int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *attr);
314
315struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
316							u64 request_mask);
317
318int p9_client_mknod_dotl(struct p9_fid *oldfid, const char *name, int mode,
319			dev_t rdev, kgid_t gid, struct p9_qid *qid);
320int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
321				kgid_t gid, struct p9_qid *qid);
322int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status);
323int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *fl);
324void p9_fcall_fini(struct p9_fcall *fc);
325struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag);
326
327static inline void p9_req_get(struct p9_req_t *r)
328{
329	refcount_inc(&r->refcount);
330}
331
332static inline int p9_req_try_get(struct p9_req_t *r)
333{
334	return refcount_inc_not_zero(&r->refcount);
335}
336
337int p9_req_put(struct p9_client *c, struct p9_req_t *r);
338
339/* We cannot have the real tracepoints in header files,
340 * use a wrapper function */
341DECLARE_TRACEPOINT(9p_fid_ref);
342void do_trace_9p_fid_get(struct p9_fid *fid);
343void do_trace_9p_fid_put(struct p9_fid *fid);
344
345/* fid reference counting helpers:
346 *  - fids used for any length of time should always be referenced through
347 *    p9_fid_get(), and released with p9_fid_put()
348 *  - v9fs_fid_lookup() or similar will automatically call get for you
349 *    and also require a put
350 *  - the *_fid_add() helpers will stash the fid in the inode,
351 *    at which point it is the responsibility of evict_inode()
352 *    to call the put
353 *  - the last put will automatically send a clunk to the server
354 */
355static inline struct p9_fid *p9_fid_get(struct p9_fid *fid)
356{
357	if (tracepoint_enabled(9p_fid_ref))
358		do_trace_9p_fid_get(fid);
359
360	refcount_inc(&fid->count);
361
362	return fid;
363}
364
365static inline int p9_fid_put(struct p9_fid *fid)
366{
367	if (!fid || IS_ERR(fid))
368		return 0;
369
370	if (tracepoint_enabled(9p_fid_ref))
371		do_trace_9p_fid_put(fid);
372
373	if (!refcount_dec_and_test(&fid->count))
374		return 0;
375
376	return p9_client_clunk(fid);
377}
378
379void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status);
380
381int p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type,
382		    int16_t *tag, int rewind);
383int p9stat_read(struct p9_client *clnt, char *buf, int len,
384		struct p9_wstat *st);
385void p9stat_free(struct p9_wstat *stbuf);
386
387int p9_is_proto_dotu(struct p9_client *clnt);
388int p9_is_proto_dotl(struct p9_client *clnt);
389struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
390				   const char *attr_name, u64 *attr_size);
391int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
392			  u64 attr_size, int flags);
393int p9_client_readlink(struct p9_fid *fid, char **target);
394
395int p9_client_init(void);
396void p9_client_exit(void);
397
398#endif /* NET_9P_CLIENT_H */