fs/btrfs/root-tree.c

   1 #include <linux/module.h>
   2 #include "ctree.h"
   3 #include "disk-io.h"
   4 #include "print-tree.h"
   5
   6 int btrfs_find_last_root(struct btrfs_root *root, u64 objectid,
   7                         struct btrfs_root_item *item, struct btrfs_key *key)
   8 {
   9         struct btrfs_path *path;
  10         struct btrfs_key search_key;
  11         struct btrfs_leaf *l;
  12         int ret;
  13         int slot;
  14
  15         search_key.objectid = objectid;
  16         search_key.flags = (u32)-1;
  17         search_key.offset = (u32)-1;
  18
  19         path = btrfs_alloc_path();
  20         BUG_ON(!path);
  21         btrfs_init_path(path);
  22         ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
  23         if (ret < 0)
  24                 goto out;
  25         BUG_ON(ret == 0);
  26         l = btrfs_buffer_leaf(path->nodes[0]);
  27         BUG_ON(path->slots[0] == 0);
  28         slot = path->slots[0] - 1;
  29         if (btrfs_disk_key_objectid(&l->items[slot].key) != objectid) {
  30                 ret = 1;
  31                 goto out;
  32         }
  33         memcpy(item, btrfs_item_ptr(l, slot, struct btrfs_root_item),
  34                 sizeof(*item));
  35         btrfs_disk_key_to_cpu(key, &l->items[slot].key);
  36         ret = 0;
  37 out:
  38         btrfs_release_path(root, path);
  39         btrfs_free_path(path);
  40         return ret;
  41 }
  42
  43 int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
  44                       *root, struct btrfs_key *key, struct btrfs_root_item
  45                       *item)
  46 {
  47         struct btrfs_path *path;
  48         struct btrfs_leaf *l;
  49         int ret;
  50         int slot;
  51         struct btrfs_root_item *update_item;
  52
  53         path = btrfs_alloc_path();
  54         BUG_ON(!path);
  55         btrfs_init_path(path);
  56         ret = btrfs_search_slot(trans, root, key, path, 0, 1);
  57         if (ret < 0)
  58                 goto out;
  59         BUG_ON(ret != 0);
  60         l = btrfs_buffer_leaf(path->nodes[0]);
  61         slot = path->slots[0];
  62         update_item = btrfs_item_ptr(l, slot, struct btrfs_root_item);
  63         btrfs_memcpy(root, l, update_item, item, sizeof(*item));
  64         btrfs_mark_buffer_dirty(path->nodes[0]);
  65 out:
  66         btrfs_release_path(root, path);
  67         btrfs_free_path(path);
  68         return ret;
  69 }
  70
  71 int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root
  72                       *root, struct btrfs_key *key, struct btrfs_root_item
  73                       *item)
  74 {
  75         int ret;
  76         ret = btrfs_insert_item(trans, root, key, item, sizeof(*item));
  77         BUG_ON(ret);
  78         return ret;
  79 }
  80
  81 int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
  82                    struct btrfs_key *key)
  83 {
  84         struct btrfs_path *path;
  85         int ret;
  86         u32 refs;
  87         struct btrfs_root_item *ri;
  88
  89         path = btrfs_alloc_path();
  90         BUG_ON(!path);
  91         btrfs_init_path(path);
  92         ret = btrfs_search_slot(trans, root, key, path, -1, 1);
  93         if (ret < 0)
  94                 goto out;
  95         BUG_ON(ret != 0);
  96         ri = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
  97                             path->slots[0], struct btrfs_root_item);
  98
  99         refs = btrfs_root_refs(ri);
 100         BUG_ON(refs == 0);
 101         if (refs == 1) {
 102                 ret = btrfs_del_item(trans, root, path);
 103         } else {
 104                 btrfs_set_root_refs(ri, refs - 1);
 105 printk("ref now %u root %Lu %Lu %u\n", refs -1, key->objectid, key->offset, key->flags);
 106                 mark_buffer_dirty(path->nodes[0]);
 107         }
 108 out:
 109         btrfs_release_path(root, path);
 110         btrfs_free_path(path);
 111         return ret;
 112 }