lib/lafs_new_segment.c

   1
   2 /* allocate a new segment at assign it to a lafs_cluster
   3  */
   4
   5 #include <lafs/lafs.h>
   6
   7 static void cluster_reset(struct lafs *fs, struct lafs_cluster *wc)
   8 {
   9         wc->remaining = dev_by_num(fs, wc->seg.dev)->segment_size;
  10         wc->chead_blocks = 1;
  11         wc->remaining--;
  12         wc->chead_size = sizeof(struct cluster_head);
  13 }
  14
  15 static void set_youth(struct lafs *fs, int dev, loff_t seg, int youth)
  16 {
  17         struct lafs_device *dv;
  18         struct lafs_dblk *db;
  19         uint16_t *p;
  20         loff_t addr;
  21
  22         dv = dev_by_num(fs, dev);
  23         addr = seg / (fs->blocksize >> YOUTH_SHIFT);
  24
  25         db = lafs_dblk(dv->segsum, addr);
  26         lafs_load_dblk(db);
  27         p = (void*)db->b.data;
  28         p[seg % (fs->blocksize >> YOUTH_SHIFT)] = __cpu_to_le16(youth);
  29         lafs_sched_blk(&db->b);
  30 }
  31
  32 int lafs_new_segment(struct lafs *fs, int cnum)
  33 {
  34         int dev;
  35         loff_t seg;
  36         struct lafs_cluster *wc = &fs->wc[cnum];
  37
  38         if (fs->free_head == fs->free_tail) {
  39                 /* list is empty */
  40                 lafs_find_free(fs);
  41                 if (fs->free_head == fs->free_tail)
  42                         return 0;
  43         }
  44         dev = fs->freelist[fs->free_head].dev;
  45         seg = fs->freelist[fs->free_head].seg;
  46
  47         fs->free_head++;
  48         if (fs->free_head > 128)
  49                 fs->free_head -= 128;
  50
  51         wc->seg.dev = dev;
  52         wc->seg.num = seg;
  53         wc->seg.st_table = 0;
  54         wc->seg.st_row = 0;
  55         wc->seg.table = wc->seg.nxt_table = wc->seg.st_table;
  56         wc->seg.row = wc->seg.nxt_row = wc->seg.st_row;
  57         wc->seg.col = 0;
  58
  59         cluster_reset(fs, wc);
  60
  61         /* Need to set the youth for this segment */
  62         set_youth(fs, dev, seg, fs->youth_next++);
  63         return 1;
  64 }