fs/reiser4/plugin/plugin_header.h

   1 /* Copyright 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
   2
   3 /* plugin header. Data structures required by all plugin types. */
   4
   5 #if !defined( __PLUGIN_HEADER_H__ )
   6 #define __PLUGIN_HEADER_H__
   7
   8 /* plugin data-types and constants */
   9
  10 #include "../debug.h"
  11 #include "../dformat.h"
  12
  13 /* Every plugin type can be considered as a class of virtual objects
  14    {(type, i) | i = 0, 1, ...}, which has one the following categories
  15    of virtualization:
  16    A - no virtualization;
  17    F - per-file virtualization;
  18    S - per-superblock virtualization;
  19    FIXME-EDWARD: Define every such category */
  20
  21 /* Supported plugin types: (id, (virtualization category), short description) */
  22 typedef enum {
  23         REISER4_FILE_PLUGIN_TYPE,             /* (F) service VFS enry-points */
  24         REISER4_DIR_PLUGIN_TYPE,              /* (F) service VFS enry-points */
  25         REISER4_ITEM_PLUGIN_TYPE,             /* (F) manage items */
  26         REISER4_NODE_PLUGIN_TYPE,             /* (S) manage formatted nodes */
  27         REISER4_HASH_PLUGIN_TYPE,             /* (F) compute hash */
  28         REISER4_FIBRATION_PLUGIN_TYPE,        /* (F) directory fibrations */
  29         REISER4_FORMATTING_PLUGIN_TYPE,       /* (F) tail-packing policy */
  30         REISER4_PERM_PLUGIN_TYPE,             /*       stub (vacancy)     */
  31         REISER4_SD_EXT_PLUGIN_TYPE,           /* (A) stat-data extensions */
  32         REISER4_FORMAT_PLUGIN_TYPE,           /* (S) specify disk format */
  33         REISER4_JNODE_PLUGIN_TYPE,            /* (A) in-memory node headers */
  34         REISER4_CIPHER_PLUGIN_TYPE,           /* (F) cipher transform algs */
  35         REISER4_DIGEST_PLUGIN_TYPE,           /* (F) digest transform algs */
  36         REISER4_COMPRESSION_PLUGIN_TYPE,      /* (F) compression tfm algs */
  37         REISER4_COMPRESSION_MODE_PLUGIN_TYPE, /* (F) compression heuristic */
  38         REISER4_CLUSTER_PLUGIN_TYPE,          /* (F) size of logical cluster */
  39         REISER4_PLUGIN_TYPES
  40 } reiser4_plugin_type;
  41
  42 /* Supported plugin groups */
  43 typedef enum {
  44         REISER4_DIRECTORY_FILE,
  45         REISER4_REGULAR_FILE,
  46         REISER4_SYMLINK_FILE,
  47         REISER4_SPECIAL_FILE,
  48 } file_plugin_group;
  49
  50 struct reiser4_plugin_ops;
  51 /* generic plugin operations, supported by each
  52     plugin type. */
  53 typedef struct reiser4_plugin_ops reiser4_plugin_ops;
  54
  55 /* the common part of all plugin instances. */
  56 typedef struct plugin_header {
  57         /* plugin type */
  58         reiser4_plugin_type type_id;
  59         /* id of this plugin */
  60         reiser4_plugin_id id;
  61         /* bitmask of groups the plugin belongs to. */
  62         reiser4_plugin_groups groups;
  63         /* plugin operations */
  64         reiser4_plugin_ops *pops;
  65 /* NIKITA-FIXME-HANS: usage of and access to label and desc is not commented and defined. */
  66         /* short label of this plugin */
  67         const char *label;
  68         /* descriptive string.. */
  69         const char *desc;
  70         /* list linkage */
  71         struct list_head linkage;
  72 } plugin_header;
  73
  74 #define plugin_of_group(plug, group) (plug->h.groups & (1 << group))
  75
  76 /* PRIVATE INTERFACES */
  77 /* NIKITA-FIXME-HANS: what is this for and why does it duplicate what is in plugin_header? */
  78 /* plugin type representation. */
  79 struct reiser4_plugin_type_data {
  80         /* internal plugin type identifier. Should coincide with
  81            index of this item in plugins[] array. */
  82         reiser4_plugin_type type_id;
  83         /* short symbolic label of this plugin type. Should be no longer
  84            than MAX_PLUGIN_TYPE_LABEL_LEN characters including '\0'. */
  85         const char *label;
  86         /* plugin type description longer than .label */
  87         const char *desc;
  88
  89 /* NIKITA-FIXME-HANS: define built-in */
  90         /* number of built-in plugin instances of this type */
  91         int builtin_num;
  92         /* array of built-in plugins */
  93         void *builtin;
  94         struct list_head plugins_list;
  95         size_t size;
  96 };
  97
  98 extern struct reiser4_plugin_type_data plugins[REISER4_PLUGIN_TYPES];
  99
 100 int is_plugin_type_valid(reiser4_plugin_type type);
 101 int is_plugin_id_valid(reiser4_plugin_type type, reiser4_plugin_id id);
 102
 103 static inline reiser4_plugin *plugin_at(struct reiser4_plugin_type_data * ptype,
 104                                         int i)
 105 {
 106         char *builtin;
 107
 108         builtin = ptype->builtin;
 109         return (reiser4_plugin *) (builtin + i * ptype->size);
 110 }
 111
 112 /* return plugin by its @type_id and @id */
 113 static inline reiser4_plugin *plugin_by_id(reiser4_plugin_type type,
 114                                            reiser4_plugin_id id)
 115 {
 116         assert("nikita-1651", is_plugin_type_valid(type));
 117         assert("nikita-1652", is_plugin_id_valid(type, id));
 118         return plugin_at(&plugins[type], id);
 119 }
 120
 121 extern reiser4_plugin *plugin_by_unsafe_id(reiser4_plugin_type type_id,
 122                                            reiser4_plugin_id id);
 123
 124 /**
 125  * plugin_by_disk_id - get reiser4_plugin
 126  * @type_id: plugin type id
 127  * @did: plugin id in disk format
 128  *
 129  * Returns reiser4_plugin by plugin type id an dplugin_id.
 130  */
 131 static inline reiser4_plugin *plugin_by_disk_id(reiser4_tree * tree UNUSED_ARG,
 132                                                 reiser4_plugin_type type_id,
 133                                                 __le16 *plugin_id)
 134 {
 135         /*
 136          * what we should do properly is to maintain within each file-system a
 137          * dictionary that maps on-disk plugin ids to "universal" ids. This
 138          * dictionary will be resolved on mount time, so that this function
 139          * will perform just one additional array lookup.
 140          */
 141         return plugin_by_unsafe_id(type_id, le16_to_cpu(*plugin_id));
 142 }
 143
 144 /* __PLUGIN_HEADER_H__ */
 145 #endif
 146
 147 /*
 148  * Local variables:
 149  * c-indentation-style: "K&R"
 150  * mode-name: "LC"
 151  * c-basic-offset: 8
 152  * tab-width: 8
 153  * fill-column: 79
 154  * End:
 155  */