fs/ceph/mds_client.h

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