1#ifndef _FS_CEPH_MDS_CLIENT_H
2#define _FS_CEPH_MDS_CLIENT_H
3
4#include <linux/completion.h>
5#include <linux/kref.h>
6#include <linux/list.h>
7#include <linux/mutex.h>
8#include <linux/rbtree.h>
9#include <linux/spinlock.h>
10
11#include <linux/ceph/types.h>
12#include <linux/ceph/messenger.h>
13#include <linux/ceph/mdsmap.h>
14#include <linux/ceph/auth.h>
15
16/*
17 * Some lock dependencies:
18 *
19 * session->s_mutex
20 *         mdsc->mutex
21 *
22 *         mdsc->snap_rwsem
23 *
24 *         ci->i_ceph_lock
25 *                 mdsc->snap_flush_lock
26 *                 mdsc->cap_delay_lock
27 *
28 */
29
30struct ceph_fs_client;
31struct ceph_cap;
32
33/*
34 * parsed info about a single inode.  pointers are into the encoded
35 * on-wire structures within the mds reply message payload.
36 */
37struct ceph_mds_reply_info_in {
38	struct ceph_mds_reply_inode *in;
39	struct ceph_dir_layout dir_layout;
40	u32 symlink_len;
41	char *symlink;
42	u32 xattr_len;
43	char *xattr_data;
44	u64 inline_version;
45	u32 inline_len;
46	char *inline_data;
47};
48
49/*
50 * parsed info about an mds reply, including information about
51 * either: 1) the target inode and/or its parent directory and dentry,
52 * and directory contents (for readdir results), or
53 * 2) the file range lock info (for fcntl F_GETLK results).
54 */
55struct ceph_mds_reply_info_parsed {
56	struct ceph_mds_reply_head    *head;
57
58	/* trace */
59	struct ceph_mds_reply_info_in diri, targeti;
60	struct ceph_mds_reply_dirfrag *dirfrag;
61	char                          *dname;
62	u32                           dname_len;
63	struct ceph_mds_reply_lease   *dlease;
64
65	/* extra */
66	union {
67		/* for fcntl F_GETLK results */
68		struct ceph_filelock *filelock_reply;
69
70		/* for readdir results */
71		struct {
72			struct ceph_mds_reply_dirfrag *dir_dir;
73			size_t			      dir_buf_size;
74			int                           dir_nr;
75			char                          **dir_dname;
76			u32                           *dir_dname_len;
77			struct ceph_mds_reply_lease   **dir_dlease;
78			struct ceph_mds_reply_info_in *dir_in;
79			u8                            dir_complete, dir_end;
80		};
81
82		/* for create results */
83		struct {
84			bool has_create_ino;
85			u64 ino;
86		};
87	};
88
89	/* encoded blob describing snapshot contexts for certain
90	   operations (e.g., open) */
91	void *snapblob;
92	int snapblob_len;
93};
94
95
96/*
97 * cap releases are batched and sent to the MDS en masse.
98 */
99#define CEPH_CAPS_PER_RELEASE ((PAGE_CACHE_SIZE -			\
100				sizeof(struct ceph_mds_cap_release)) /	\
101			       sizeof(struct ceph_mds_cap_item))
102
103
104/*
105 * state associated with each MDS<->client session
106 */
107enum {
108	CEPH_MDS_SESSION_NEW = 1,
109	CEPH_MDS_SESSION_OPENING = 2,
110	CEPH_MDS_SESSION_OPEN = 3,
111	CEPH_MDS_SESSION_HUNG = 4,
112	CEPH_MDS_SESSION_CLOSING = 5,
113	CEPH_MDS_SESSION_RESTARTING = 6,
114	CEPH_MDS_SESSION_RECONNECTING = 7,
115};
116
117struct ceph_mds_session {
118	struct ceph_mds_client *s_mdsc;
119	int               s_mds;
120	int               s_state;
121	unsigned long     s_ttl;      /* time until mds kills us */
122	u64               s_seq;      /* incoming msg seq # */
123	struct mutex      s_mutex;    /* serialize session messages */
124
125	struct ceph_connection s_con;
126
127	struct ceph_auth_handshake s_auth;
128
129	/* protected by s_gen_ttl_lock */
130	spinlock_t        s_gen_ttl_lock;
131	u32               s_cap_gen;  /* inc each time we get mds stale msg */
132	unsigned long     s_cap_ttl;  /* when session caps expire */
133
134	/* protected by s_cap_lock */
135	spinlock_t        s_cap_lock;
136	struct list_head  s_caps;     /* all caps issued by this session */
137	int               s_nr_caps, s_trim_caps;
138	int               s_num_cap_releases;
139	int		  s_cap_reconnect;
140	int		  s_readonly;
141	struct list_head  s_cap_releases; /* waiting cap_release messages */
142	struct list_head  s_cap_releases_done; /* ready to send */
143	struct ceph_cap  *s_cap_iterator;
144
145	/* protected by mutex */
146	struct list_head  s_cap_flushing;     /* inodes w/ flushing caps */
147	struct list_head  s_cap_snaps_flushing;
148	unsigned long     s_renew_requested; /* last time we sent a renew req */
149	u64               s_renew_seq;
150
151	atomic_t          s_ref;
152	struct list_head  s_waiting;  /* waiting requests */
153	struct list_head  s_unsafe;   /* unsafe requests */
154};
155
156/*
157 * modes of choosing which MDS to send a request to
158 */
159enum {
160	USE_ANY_MDS,
161	USE_RANDOM_MDS,
162	USE_AUTH_MDS,   /* prefer authoritative mds for this metadata item */
163};
164
165struct ceph_mds_request;
166struct ceph_mds_client;
167
168/*
169 * request completion callback
170 */
171typedef void (*ceph_mds_request_callback_t) (struct ceph_mds_client *mdsc,
172					     struct ceph_mds_request *req);
173/*
174 * wait for request completion callback
175 */
176typedef int (*ceph_mds_request_wait_callback_t) (struct ceph_mds_client *mdsc,
177						 struct ceph_mds_request *req);
178
179/*
180 * an in-flight mds request
181 */
182struct ceph_mds_request {
183	u64 r_tid;                   /* transaction id */
184	struct rb_node r_node;
185	struct ceph_mds_client *r_mdsc;
186
187	int r_op;                    /* mds op code */
188
189	/* operation on what? */
190	struct inode *r_inode;              /* arg1 */
191	struct dentry *r_dentry;            /* arg1 */
192	struct dentry *r_old_dentry;        /* arg2: rename from or link from */
193	struct inode *r_old_dentry_dir;     /* arg2: old dentry's parent dir */
194	char *r_path1, *r_path2;
195	struct ceph_vino r_ino1, r_ino2;
196
197	struct inode *r_locked_dir; /* dir (if any) i_mutex locked by vfs */
198	struct inode *r_target_inode;       /* resulting inode */
199
200	struct mutex r_fill_mutex;
201
202	union ceph_mds_request_args r_args;
203	int r_fmode;        /* file mode, if expecting cap */
204	kuid_t r_uid;
205	kgid_t r_gid;
206	struct timespec r_stamp;
207
208	/* for choosing which mds to send this request to */
209	int r_direct_mode;
210	u32 r_direct_hash;      /* choose dir frag based on this dentry hash */
211	bool r_direct_is_hash;  /* true if r_direct_hash is valid */
212
213	/* data payload is used for xattr ops */
214	struct ceph_pagelist *r_pagelist;
215
216	/* what caps shall we drop? */
217	int r_inode_drop, r_inode_unless;
218	int r_dentry_drop, r_dentry_unless;
219	int r_old_dentry_drop, r_old_dentry_unless;
220	struct inode *r_old_inode;
221	int r_old_inode_drop, r_old_inode_unless;
222
223	struct ceph_msg  *r_request;  /* original request */
224	int r_request_release_offset;
225	struct ceph_msg  *r_reply;
226	struct ceph_mds_reply_info_parsed r_reply_info;
227	struct page *r_locked_page;
228	int r_err;
229	bool r_aborted;
230
231	unsigned long r_timeout;  /* optional.  jiffies */
232	unsigned long r_started;  /* start time to measure timeout against */
233	unsigned long r_request_started; /* start time for mds request only,
234					    used to measure lease durations */
235
236	/* link unsafe requests to parent directory, for fsync */
237	struct inode	*r_unsafe_dir;
238	struct list_head r_unsafe_dir_item;
239
240	struct ceph_mds_session *r_session;
241
242	int               r_attempts;   /* resend attempts */
243	int               r_num_fwd;    /* number of forward attempts */
244	int               r_resend_mds; /* mds to resend to next, if any*/
245	u32               r_sent_on_mseq; /* cap mseq request was sent at*/
246
247	struct kref       r_kref;
248	struct list_head  r_wait;
249	struct completion r_completion;
250	struct completion r_safe_completion;
251	ceph_mds_request_callback_t r_callback;
252	ceph_mds_request_wait_callback_t r_wait_for_completion;
253	struct list_head  r_unsafe_item;  /* per-session unsafe list item */
254	bool		  r_got_unsafe, r_got_safe, r_got_result;
255
256	bool              r_did_prepopulate;
257	u32               r_readdir_offset;
258
259	struct ceph_cap_reservation r_caps_reservation;
260	int r_num_caps;
261};
262
263/*
264 * mds client state
265 */
266struct ceph_mds_client {
267	struct ceph_fs_client  *fsc;
268	struct mutex            mutex;         /* all nested structures */
269
270	struct ceph_mdsmap      *mdsmap;
271	struct completion       safe_umount_waiters;
272	wait_queue_head_t       session_close_wq;
273	struct list_head        waiting_for_map;
274
275	struct ceph_mds_session **sessions;    /* NULL for mds if no session */
276	atomic_t		num_sessions;
277	int                     max_sessions;  /* len of s_mds_sessions */
278	int                     stopping;      /* true if shutting down */
279
280	/*
281	 * snap_rwsem will cover cap linkage into snaprealms, and
282	 * realm snap contexts.  (later, we can do per-realm snap
283	 * contexts locks..)  the empty list contains realms with no
284	 * references (implying they contain no inodes with caps) that
285	 * should be destroyed.
286	 */
287	struct rw_semaphore     snap_rwsem;
288	struct rb_root          snap_realms;
289	struct list_head        snap_empty;
290	spinlock_t              snap_empty_lock;  /* protect snap_empty */
291
292	u64                    last_tid;      /* most recent mds request */
293	struct rb_root         request_tree;  /* pending mds requests */
294	struct delayed_work    delayed_work;  /* delayed work */
295	unsigned long    last_renew_caps;  /* last time we renewed our caps */
296	struct list_head cap_delay_list;   /* caps with delayed release */
297	spinlock_t       cap_delay_lock;   /* protects cap_delay_list */
298	struct list_head snap_flush_list;  /* cap_snaps ready to flush */
299	spinlock_t       snap_flush_lock;
300
301	u64               cap_flush_seq;
302	struct list_head  cap_dirty;        /* inodes with dirty caps */
303	struct list_head  cap_dirty_migrating; /* ...that are migration... */
304	int               num_cap_flushing; /* # caps we are flushing */
305	spinlock_t        cap_dirty_lock;   /* protects above items */
306	wait_queue_head_t cap_flushing_wq;
307
308	/*
309	 * Cap reservations
310	 *
311	 * Maintain a global pool of preallocated struct ceph_caps, referenced
312	 * by struct ceph_caps_reservations.  This ensures that we preallocate
313	 * memory needed to successfully process an MDS response.  (If an MDS
314	 * sends us cap information and we fail to process it, we will have
315	 * problems due to the client and MDS being out of sync.)
316	 *
317	 * Reservations are 'owned' by a ceph_cap_reservation context.
318	 */
319	spinlock_t	caps_list_lock;
320	struct		list_head caps_list; /* unused (reserved or
321						unreserved) */
322	int		caps_total_count;    /* total caps allocated */
323	int		caps_use_count;      /* in use */
324	int		caps_reserve_count;  /* unused, reserved */
325	int		caps_avail_count;    /* unused, unreserved */
326	int		caps_min_count;      /* keep at least this many
327						(unreserved) */
328	spinlock_t	  dentry_lru_lock;
329	struct list_head  dentry_lru;
330	int		  num_dentry;
331};
332
333extern const char *ceph_mds_op_name(int op);
334
335extern struct ceph_mds_session *
336__ceph_lookup_mds_session(struct ceph_mds_client *, int mds);
337
338static inline struct ceph_mds_session *
339ceph_get_mds_session(struct ceph_mds_session *s)
340{
341	atomic_inc(&s->s_ref);
342	return s;
343}
344
345extern const char *ceph_session_state_name(int s);
346
347extern void ceph_put_mds_session(struct ceph_mds_session *s);
348
349extern int ceph_send_msg_mds(struct ceph_mds_client *mdsc,
350			     struct ceph_msg *msg, int mds);
351
352extern int ceph_mdsc_init(struct ceph_fs_client *fsc);
353extern void ceph_mdsc_close_sessions(struct ceph_mds_client *mdsc);
354extern void ceph_mdsc_destroy(struct ceph_fs_client *fsc);
355
356extern void ceph_mdsc_sync(struct ceph_mds_client *mdsc);
357
358extern void ceph_mdsc_lease_release(struct ceph_mds_client *mdsc,
359				    struct inode *inode,
360				    struct dentry *dn);
361
362extern void ceph_invalidate_dir_request(struct ceph_mds_request *req);
363extern int ceph_alloc_readdir_reply_buffer(struct ceph_mds_request *req,
364					   struct inode *dir);
365extern struct ceph_mds_request *
366ceph_mdsc_create_request(struct ceph_mds_client *mdsc, int op, int mode);
367extern void ceph_mdsc_submit_request(struct ceph_mds_client *mdsc,
368				     struct ceph_mds_request *req);
369extern int ceph_mdsc_do_request(struct ceph_mds_client *mdsc,
370				struct inode *dir,
371				struct ceph_mds_request *req);
372static inline void ceph_mdsc_get_request(struct ceph_mds_request *req)
373{
374	kref_get(&req->r_kref);
375}
376extern void ceph_mdsc_release_request(struct kref *kref);
377static inline void ceph_mdsc_put_request(struct ceph_mds_request *req)
378{
379	kref_put(&req->r_kref, ceph_mdsc_release_request);
380}
381
382extern int ceph_add_cap_releases(struct ceph_mds_client *mdsc,
383				 struct ceph_mds_session *session);
384extern void ceph_send_cap_releases(struct ceph_mds_client *mdsc,
385				   struct ceph_mds_session *session);
386
387extern void ceph_mdsc_pre_umount(struct ceph_mds_client *mdsc);
388
389extern char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *base,
390				  int stop_on_nosnap);
391
392extern void __ceph_mdsc_drop_dentry_lease(struct dentry *dentry);
393extern void ceph_mdsc_lease_send_msg(struct ceph_mds_session *session,
394				     struct inode *inode,
395				     struct dentry *dentry, char action,
396				     u32 seq);
397
398extern void ceph_mdsc_handle_map(struct ceph_mds_client *mdsc,
399				 struct ceph_msg *msg);
400
401extern struct ceph_mds_session *
402ceph_mdsc_open_export_target_session(struct ceph_mds_client *mdsc, int target);
403extern void ceph_mdsc_open_export_target_sessions(struct ceph_mds_client *mdsc,
404					  struct ceph_mds_session *session);
405
406#endif
407