fs/reiser4/plugin/item/ctail.h

   1 /* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
   2
   3 /* Ctail items are fragments (or bodies) of special tipe to provide
   4    optimal storage of encrypted and(or) compressed files. */
   5
   6
   7 #if !defined( __FS_REISER4_CTAIL_H__ )
   8 #define __FS_REISER4_CTAIL_H__
   9
  10 /* Disk format of ctail item */
  11 typedef struct ctail_item_format {
  12         /* packed shift;
  13            if its value is different from UCTAIL_SHIFT (see below), then
  14            size of disk cluster is calculated as (1 << cluster_shift) */
  15         d8 cluster_shift;
  16         /* ctail body */
  17         d8 body[0];
  18 } __attribute__ ((packed)) ctail_item_format;
  19
  20 /* "Unprepped" disk cluster is represented by a single ctail item
  21    with the following "magic" attributes: */
  22 /* "magic" cluster_shift */
  23 #define UCTAIL_SHIFT 0xff
  24 /* How many units unprepped ctail item has */
  25 #define UCTAIL_NR_UNITS 1
  26
  27 /* The following is a set of various item states in a disk cluster.
  28    Disk cluster is a set of items whose keys belong to the interval
  29    [dc_key , dc_key + disk_cluster_size - 1] */
  30 typedef enum {
  31         DC_INVALID_STATE = 0,
  32         DC_FIRST_ITEM = 1,
  33         DC_CHAINED_ITEM = 2,
  34         DC_AFTER_CLUSTER = 3
  35 } dc_item_stat;
  36
  37 /* ctail-specific extension.
  38    In particular this describes parameters of disk cluster an item belongs to */
  39 struct ctail_coord_extension {
  40         int shift; /* this contains cluster_shift extracted from
  41                       ctail_item_format (above), or UCTAIL_SHIFT
  42                       (the last one is the "magic" of unprepped disk clusters)*/
  43         int dsize; /* size of a prepped disk cluster */
  44         int ncount; /* count of nodes occupied by a disk cluster */
  45 };
  46
  47 struct cut_list;
  48
  49 /* plugin->item.b.* */
  50 int can_contain_key_ctail(const coord_t *, const reiser4_key *,
  51                           const reiser4_item_data *);
  52 int mergeable_ctail(const coord_t * p1, const coord_t * p2);
  53 pos_in_node_t nr_units_ctail(const coord_t * coord);
  54 int estimate_ctail(const coord_t * coord, const reiser4_item_data * data);
  55 void print_ctail(const char *prefix, coord_t * coord);
  56 lookup_result lookup_ctail(const reiser4_key *, lookup_bias, coord_t *);
  57
  58 int paste_ctail(coord_t * coord, reiser4_item_data * data,
  59                 carry_plugin_info * info UNUSED_ARG);
  60 int init_ctail(coord_t *, coord_t *, reiser4_item_data *);
  61 int can_shift_ctail(unsigned free_space, coord_t * coord,
  62                     znode * target, shift_direction pend, unsigned *size,
  63                     unsigned want);
  64 void copy_units_ctail(coord_t * target, coord_t * source, unsigned from,
  65                       unsigned count, shift_direction where_is_free_space,
  66                       unsigned free_space);
  67 int cut_units_ctail(coord_t * coord, pos_in_node_t from, pos_in_node_t to,
  68                     carry_cut_data *, reiser4_key * smallest_removed,
  69                     reiser4_key * new_first);
  70 int kill_units_ctail(coord_t * coord, pos_in_node_t from, pos_in_node_t to,
  71                      carry_kill_data *, reiser4_key * smallest_removed,
  72                      reiser4_key * new_first);
  73 int ctail_ok(const coord_t * coord);
  74 int check_ctail(const coord_t * coord, const char **error);
  75
  76 /* plugin->u.item.s.* */
  77 int read_ctail(struct file *, flow_t *, hint_t *);
  78 int readpage_ctail(void *, struct page *);
  79 int readpages_ctail(struct file *, struct address_space *, struct list_head *);
  80 reiser4_key *append_key_ctail(const coord_t *, reiser4_key *);
  81 int create_hook_ctail(const coord_t * coord, void *arg);
  82 int kill_hook_ctail(const coord_t *, pos_in_node_t, pos_in_node_t,
  83                     carry_kill_data *);
  84 int shift_hook_ctail(const coord_t *, unsigned, unsigned, znode *);
  85
  86 /* plugin->u.item.f */
  87 int utmost_child_ctail(const coord_t *, sideof, jnode **);
  88 int scan_ctail(flush_scan *);
  89 int convert_ctail(flush_pos_t *);
  90 size_t inode_scaled_cluster_size(struct inode *);
  91
  92 #endif                          /* __FS_REISER4_CTAIL_H__ */
  93
  94 /* Make Linus happy.
  95    Local variables:
  96    c-indentation-style: "K&R"
  97    mode-name: "LC"
  98    c-basic-offset: 8
  99    tab-width: 8
 100    fill-column: 120
 101    End:
 102 */