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