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