linux/fs/ceph/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
  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};
  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 */
  52struct 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 */
 103enum {
 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
 113struct 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 */
 154enum {
 155        USE_ANY_MDS,
 156        USE_RANDOM_MDS,
 157        USE_AUTH_MDS,   /* prefer authoritative mds for this metadata item */
 158};
 159
 160struct ceph_mds_request;
 161struct ceph_mds_client;
 162
 163/*
 164 * request completion callback
 165 */
 166typedef 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 */
 172struct 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 */
 255struct 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
 321extern const char *ceph_mds_op_name(int op);
 322
 323extern struct ceph_mds_session *
 324__ceph_lookup_mds_session(struct ceph_mds_client *, int mds);
 325
 326static inline struct ceph_mds_session *
 327ceph_get_mds_session(struct ceph_mds_session *s)
 328{
 329        atomic_inc(&s->s_ref);
 330        return s;
 331}
 332
 333extern void ceph_put_mds_session(struct ceph_mds_session *s);
 334
 335extern int ceph_send_msg_mds(struct ceph_mds_client *mdsc,
 336                             struct ceph_msg *msg, int mds);
 337
 338extern int ceph_mdsc_init(struct ceph_fs_client *fsc);
 339extern void ceph_mdsc_close_sessions(struct ceph_mds_client *mdsc);
 340extern void ceph_mdsc_destroy(struct ceph_fs_client *fsc);
 341
 342extern void ceph_mdsc_sync(struct ceph_mds_client *mdsc);
 343
 344extern void ceph_mdsc_lease_release(struct ceph_mds_client *mdsc,
 345                                    struct inode *inode,
 346                                    struct dentry *dn);
 347
 348extern void ceph_invalidate_dir_request(struct ceph_mds_request *req);
 349
 350extern struct ceph_mds_request *
 351ceph_mdsc_create_request(struct ceph_mds_client *mdsc, int op, int mode);
 352extern void ceph_mdsc_submit_request(struct ceph_mds_client *mdsc,
 353                                     struct ceph_mds_request *req);
 354extern int ceph_mdsc_do_request(struct ceph_mds_client *mdsc,
 355                                struct inode *dir,
 356                                struct ceph_mds_request *req);
 357static inline void ceph_mdsc_get_request(struct ceph_mds_request *req)
 358{
 359        kref_get(&req->r_kref);
 360}
 361extern void ceph_mdsc_release_request(struct kref *kref);
 362static inline void ceph_mdsc_put_request(struct ceph_mds_request *req)
 363{
 364        kref_put(&req->r_kref, ceph_mdsc_release_request);
 365}
 366
 367extern int ceph_add_cap_releases(struct ceph_mds_client *mdsc,
 368                                 struct ceph_mds_session *session);
 369extern void ceph_send_cap_releases(struct ceph_mds_client *mdsc,
 370                                   struct ceph_mds_session *session);
 371
 372extern void ceph_mdsc_pre_umount(struct ceph_mds_client *mdsc);
 373
 374extern char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *base,
 375                                  int stop_on_nosnap);
 376
 377extern void __ceph_mdsc_drop_dentry_lease(struct dentry *dentry);
 378extern 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
 383extern void ceph_mdsc_handle_map(struct ceph_mds_client *mdsc,
 384                                 struct ceph_msg *msg);
 385
 386extern void ceph_mdsc_open_export_target_sessions(struct ceph_mds_client *mdsc,
 387                                          struct ceph_mds_session *session);
 388
 389#endif
 390