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