fs/btrfs/file-item.c

   1 #include <linux/module.h>
   2 #include "ctree.h"
   3 #include "disk-io.h"
   4 #include "transaction.h"
   5
   6 int btrfs_alloc_file_extent(struct btrfs_trans_handle *trans,
   7                                struct btrfs_root *root,
   8                                u64 objectid, u64 offset,
   9                                u64 num_blocks, u64 hint_block,
  10                                u64 *result)
  11 {
  12         struct btrfs_key ins;
  13         int ret = 0;
  14         struct btrfs_file_extent_item *item;
  15         struct btrfs_key file_key;
  16         struct btrfs_path path;
  17
  18         btrfs_init_path(&path);
  19         ret = btrfs_alloc_extent(trans, root, num_blocks, hint_block,
  20                                  (u64)-1, objectid, &ins);
  21         BUG_ON(ret);
  22         file_key.objectid = objectid;
  23         file_key.offset = offset;
  24         file_key.flags = 0;
  25         btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
  26
  27         ret = btrfs_insert_empty_item(trans, root, &path, &file_key,
  28                                       sizeof(*item));
  29         BUG_ON(ret);
  30         item = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]), path.slots[0],
  31                               struct btrfs_file_extent_item);
  32         btrfs_set_file_extent_disk_blocknr(item, ins.objectid);
  33         btrfs_set_file_extent_disk_num_blocks(item, ins.offset);
  34         btrfs_set_file_extent_offset(item, 0);
  35         btrfs_set_file_extent_num_blocks(item, ins.offset);
  36         btrfs_set_file_extent_generation(item, trans->transid);
  37         mark_buffer_dirty(path.nodes[0]);
  38         *result = ins.objectid;
  39         btrfs_release_path(root, &path);
  40         return 0;
  41 }
  42
  43 int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
  44                              struct btrfs_root *root,
  45                              struct btrfs_path *path, u64 objectid,
  46                              u64 offset, int mod)
  47 {
  48         int ret;
  49         struct btrfs_key file_key;
  50         int ins_len = mod < 0 ? -1 : 0;
  51         int cow = mod != 0;
  52
  53         file_key.objectid = objectid;
  54         file_key.offset = offset;
  55         file_key.flags = 0;
  56         btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
  57         ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
  58         return ret;
  59 }
  60
  61 int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
  62                           struct btrfs_root *root,
  63                           u64 objectid, u64 offset,
  64                           char *data, size_t len)
  65 {
  66         int ret;
  67         struct btrfs_key file_key;
  68         struct btrfs_path path;
  69         struct btrfs_csum_item *item;
  70
  71         btrfs_init_path(&path);
  72         file_key.objectid = objectid;
  73         file_key.offset = offset;
  74         file_key.flags = 0;
  75         btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
  76         ret = btrfs_insert_empty_item(trans, root, &path, &file_key,
  77                                       BTRFS_CSUM_SIZE);
  78         if (ret != 0 && ret != -EEXIST)
  79                 goto fail;
  80         item = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]), path.slots[0],
  81                               struct btrfs_csum_item);
  82         ret = 0;
  83         ret = btrfs_csum_data(root, data, len, item->csum);
  84         mark_buffer_dirty(path.nodes[0]);
  85 fail:
  86         btrfs_release_path(root, &path);
  87         return ret;
  88 }
  89
  90 int btrfs_csum_verify_file_block(struct btrfs_root *root,
  91                                  u64 objectid, u64 offset,
  92                                  char *data, size_t len)
  93 {
  94         int ret;
  95         struct btrfs_key file_key;
  96         struct btrfs_path path;
  97         struct btrfs_csum_item *item;
  98         char result[BTRFS_CSUM_SIZE];
  99
 100         btrfs_init_path(&path);
 101         file_key.objectid = objectid;
 102         file_key.offset = offset;
 103         file_key.flags = 0;
 104         btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
 105         ret = btrfs_search_slot(NULL, root, &file_key, &path, 0, 0);
 106         if (ret)
 107                 goto fail;
 108         item = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]), path.slots[0],
 109                               struct btrfs_csum_item);
 110         ret = 0;
 111         ret = btrfs_csum_data(root, data, len, result);
 112         WARN_ON(ret);
 113         if (memcmp(result, item->csum, BTRFS_CSUM_SIZE))
 114                 ret = 1;
 115 fail:
 116         btrfs_release_path(root, &path);
 117         return ret;
 118 }
 119