fs/reiser4/plugin/item/extent.c

   1 /* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
   2
   3 #include "item.h"
   4 #include "../../key.h"
   5 #include "../../super.h"
   6 #include "../../carry.h"
   7 #include "../../inode.h"
   8 #include "../../page_cache.h"
   9 #include "../../flush.h"
  10 #include "../object.h"
  11
  12 /* prepare structure reiser4_item_data. It is used to put one extent unit into tree */
  13 /* Audited by: green(2002.06.13) */
  14 reiser4_item_data *init_new_extent(reiser4_item_data * data, void *ext_unit,
  15                                    int nr_extents)
  16 {
  17         data->data = ext_unit;
  18         /* data->data is kernel space */
  19         data->user = 0;
  20         data->length = sizeof(reiser4_extent) * nr_extents;
  21         data->arg = NULL;
  22         data->iplug = item_plugin_by_id(EXTENT_POINTER_ID);
  23         return data;
  24 }
  25
  26 /* how many bytes are addressed by @nr first extents of the extent item */
  27 reiser4_block_nr reiser4_extent_size(const coord_t * coord, pos_in_node_t nr)
  28 {
  29         pos_in_node_t i;
  30         reiser4_block_nr blocks;
  31         reiser4_extent *ext;
  32
  33         ext = item_body_by_coord(coord);
  34         assert("vs-263", nr <= nr_units_extent(coord));
  35
  36         blocks = 0;
  37         for (i = 0; i < nr; i++, ext++) {
  38                 blocks += extent_get_width(ext);
  39         }
  40
  41         return blocks * current_blocksize;
  42 }
  43
  44 extent_state state_of_extent(reiser4_extent * ext)
  45 {
  46         switch ((int)extent_get_start(ext)) {
  47         case 0:
  48                 return HOLE_EXTENT;
  49         case 1:
  50                 return UNALLOCATED_EXTENT;
  51         default:
  52                 break;
  53         }
  54         return ALLOCATED_EXTENT;
  55 }
  56
  57 int extent_is_unallocated(const coord_t * item)
  58 {
  59         assert("jmacd-5133", item_is_extent(item));
  60
  61         return state_of_extent(extent_by_coord(item)) == UNALLOCATED_EXTENT;
  62 }
  63
  64 /* set extent's start and width */
  65 void reiser4_set_extent(reiser4_extent * ext, reiser4_block_nr start,
  66                         reiser4_block_nr width)
  67 {
  68         extent_set_start(ext, start);
  69         extent_set_width(ext, width);
  70 }
  71
  72 /**
  73  * reiser4_replace_extent - replace extent and paste 1 or 2 after it
  74  * @un_extent: coordinate of extent to be overwritten
  75  * @lh: need better comment
  76  * @key: need better comment
  77  * @exts_to_add: data prepared for insertion into tree
  78  * @replace: need better comment
  79  * @flags: need better comment
  80  * @return_insert_position: need better comment
  81  *
  82  * Overwrites one extent, pastes 1 or 2 more ones after overwritten one.  If
  83  * @return_inserted_position is 1 - @un_extent and @lh are returned set to
  84  * first of newly inserted units, if it is 0 - @un_extent and @lh are returned
  85  * set to extent which was overwritten.
  86  */
  87 int reiser4_replace_extent(struct replace_handle *h,
  88                            int return_inserted_position)
  89 {
  90         int result;
  91         znode *orig_znode;
  92         /*ON_DEBUG(reiser4_extent orig_ext);*/  /* this is for debugging */
  93
  94         assert("vs-990", coord_is_existing_unit(h->coord));
  95         assert("vs-1375", znode_is_write_locked(h->coord->node));
  96         assert("vs-1426", extent_get_width(&h->overwrite) != 0);
  97         assert("vs-1427", extent_get_width(&h->new_extents[0]) != 0);
  98         assert("vs-1427", ergo(h->nr_new_extents == 2,
  99                                extent_get_width(&h->new_extents[1]) != 0));
 100
 101         /* compose structure for paste */
 102         init_new_extent(&h->item, &h->new_extents[0], h->nr_new_extents);
 103
 104         coord_dup(&h->coord_after, h->coord);
 105         init_lh(&h->lh_after);
 106         copy_lh(&h->lh_after, h->lh);
 107         reiser4_tap_init(&h->watch, &h->coord_after, &h->lh_after, ZNODE_WRITE_LOCK);
 108         reiser4_tap_monitor(&h->watch);
 109
 110         ON_DEBUG(h->orig_ext = *extent_by_coord(h->coord));
 111         orig_znode = h->coord->node;
 112
 113 #if REISER4_DEBUG
 114         /* make sure that key is set properly */
 115         unit_key_by_coord(h->coord, &h->tmp);
 116         set_key_offset(&h->tmp,
 117                        get_key_offset(&h->tmp) +
 118                        extent_get_width(&h->overwrite) * current_blocksize);
 119         assert("vs-1080", keyeq(&h->tmp, &h->paste_key));
 120 #endif
 121
 122         /* set insert point after unit to be replaced */
 123         h->coord->between = AFTER_UNIT;
 124
 125         result = insert_into_item(h->coord, return_inserted_position ? h->lh : NULL,
 126                                   &h->paste_key, &h->item, h->flags);
 127         if (!result) {
 128                 /* now we have to replace the unit after which new units were
 129                    inserted. Its position is tracked by @watch */
 130                 reiser4_extent *ext;
 131                 znode *node;
 132
 133                 node = h->coord_after.node;
 134                 if (node != orig_znode) {
 135                         coord_clear_iplug(&h->coord_after);
 136                         result = zload(node);
 137                 }
 138
 139                 if (likely(!result)) {
 140                         ext = extent_by_coord(&h->coord_after);
 141
 142                         assert("vs-987", znode_is_loaded(node));
 143                         assert("vs-988", !memcmp(ext, &h->orig_ext, sizeof(*ext)));
 144
 145                         /* overwrite extent unit */
 146                         memcpy(ext, &h->overwrite, sizeof(reiser4_extent));
 147                         znode_make_dirty(node);
 148
 149                         if (node != orig_znode)
 150                                 zrelse(node);
 151
 152                         if (return_inserted_position == 0) {
 153                                 /* coord and lh are to be set to overwritten
 154                                    extent */
 155                                 assert("vs-1662",
 156                                        WITH_DATA(node, !memcmp(&h->overwrite,
 157                                                                extent_by_coord(
 158                                                                        &h->coord_after),
 159                                                                sizeof(reiser4_extent))));
 160
 161                                 *h->coord = h->coord_after;
 162                                 done_lh(h->lh);
 163                                 copy_lh(h->lh, &h->lh_after);
 164                         } else {
 165                                 /* h->coord and h->lh are to be set to first of
 166                                    inserted units */
 167                                 assert("vs-1663",
 168                                        WITH_DATA(h->coord->node,
 169                                                  !memcmp(&h->new_extents[0],
 170                                                          extent_by_coord(h->coord),
 171                                                          sizeof(reiser4_extent))));
 172                                 assert("vs-1664", h->lh->node == h->coord->node);
 173                         }
 174                 }
 175         }
 176         reiser4_tap_done(&h->watch);
 177
 178         return result;
 179 }
 180
 181 lock_handle *znode_lh(znode *node)
 182 {
 183         assert("vs-1371", znode_is_write_locked(node));
 184         assert("vs-1372", znode_is_wlocked_once(node));
 185         return list_entry(node->lock.owners.next, lock_handle, owners_link);
 186 }
 187
 188 /*
 189  * Local variables:
 190  * c-indentation-style: "K&R"
 191  * mode-name: "LC"
 192  * c-basic-offset: 8
 193  * tab-width: 8
 194  * fill-column: 79
 195  * scroll-step: 1
 196  * End:
 197  */