fs/reiser4/tap.h

   1 /* Copyright 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
   2
   3 /* Tree Access Pointers. See tap.c for more details. */
   4
   5 #if !defined( __REISER4_TAP_H__ )
   6 #define __REISER4_TAP_H__
   7
   8 #include "forward.h"
   9 #include "readahead.h"
  10
  11 /**
  12     tree_access_pointer aka tap. Data structure combining coord_t and lock
  13     handle.
  14     Invariants involving this data-type, see doc/lock-ordering for details:
  15
  16       [tap-sane]
  17  */
  18 struct tree_access_pointer {
  19         /* coord tap is at */
  20         coord_t *coord;
  21         /* lock handle on ->coord->node */
  22         lock_handle *lh;
  23         /* mode of lock acquired by this tap */
  24         znode_lock_mode mode;
  25         /* incremented by reiser4_tap_load().
  26            Decremented by reiser4_tap_relse(). */
  27         int loaded;
  28         /* list of taps */
  29         struct list_head linkage;
  30         /* read-ahead hint */
  31         ra_info_t ra_info;
  32 };
  33
  34 typedef int (*go_actor_t) (tap_t * tap);
  35
  36 extern int reiser4_tap_load(tap_t * tap);
  37 extern void reiser4_tap_relse(tap_t * tap);
  38 extern void reiser4_tap_init(tap_t * tap, coord_t * coord, lock_handle * lh,
  39                      znode_lock_mode mode);
  40 extern void reiser4_tap_monitor(tap_t * tap);
  41 extern void reiser4_tap_copy(tap_t * dst, tap_t * src);
  42 extern void reiser4_tap_done(tap_t * tap);
  43 extern int reiser4_tap_move(tap_t * tap, lock_handle * target);
  44 extern int tap_to_coord(tap_t * tap, coord_t * target);
  45
  46 extern int go_dir_el(tap_t * tap, sideof dir, int units_p);
  47 extern int go_next_unit(tap_t * tap);
  48 extern int go_prev_unit(tap_t * tap);
  49 extern int rewind_right(tap_t * tap, int shift);
  50 extern int rewind_left(tap_t * tap, int shift);
  51
  52 extern struct list_head *reiser4_taps_list(void);
  53
  54 #define for_all_taps(tap)                                                      \
  55         for (tap = list_entry(reiser4_taps_list()->next, tap_t, linkage);      \
  56              reiser4_taps_list() != &tap->linkage;                             \
  57              tap = list_entry(tap->linkage.next, tap_t, linkage))
  58
  59 /* __REISER4_TAP_H__ */
  60 #endif
  61 /* Make Linus happy.
  62    Local variables:
  63    c-indentation-style: "K&R"
  64    mode-name: "LC"
  65    c-basic-offset: 8
  66    tab-width: 8
  67    fill-column: 120
  68    scroll-step: 1
  69    End:
  70 */