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         path = btrfs_alloc_path();
  19         BUG_ON(!path);
  20         btrfs_init_path(path);
  21         ret = btrfs_alloc_extent(trans, root, num_blocks, hint_block,
  22                                  (u64)-1, objectid, &ins);
  23         BUG_ON(ret);
  24         file_key.objectid = objectid;
  25         file_key.offset = offset;
  26         file_key.flags = 0;
  27         btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
  28
  29         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
  30                                       sizeof(*item));
  31         BUG_ON(ret);
  32         item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
  33                               struct btrfs_file_extent_item);
  34         btrfs_set_file_extent_disk_blocknr(item, ins.objectid);
  35         btrfs_set_file_extent_disk_num_blocks(item, ins.offset);
  36         btrfs_set_file_extent_offset(item, 0);
  37         btrfs_set_file_extent_num_blocks(item, ins.offset);
  38         btrfs_set_file_extent_generation(item, trans->transid);
  39         btrfs_mark_buffer_dirty(path->nodes[0]);
  40         *result = ins.objectid;
  41         btrfs_release_path(root, path);
  42         btrfs_free_path(path);
  43         return 0;
  44 }
  45
  46 int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
  47                              struct btrfs_root *root,
  48                              struct btrfs_path *path, u64 objectid,
  49                              u64 offset, int mod)
  50 {
  51         int ret;
  52         struct btrfs_key file_key;
  53         int ins_len = mod < 0 ? -1 : 0;
  54         int cow = mod != 0;
  55
  56         file_key.objectid = objectid;
  57         file_key.offset = offset;
  58         file_key.flags = 0;
  59         btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
  60         ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
  61         return ret;
  62 }
  63
  64 int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
  65                           struct btrfs_root *root,
  66                           u64 objectid, u64 offset,
  67                           char *data, size_t len)
  68 {
  69         int ret;
  70         struct btrfs_key file_key;
  71         struct btrfs_path *path;
  72         struct btrfs_csum_item *item;
  73
  74         path = btrfs_alloc_path();
  75         BUG_ON(!path);
  76         btrfs_init_path(path);
  77         file_key.objectid = objectid;
  78         file_key.offset = offset;
  79         file_key.flags = 0;
  80         btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
  81         ret = btrfs_insert_empty_item(trans, root, path, &file_key,
  82                                       BTRFS_CSUM_SIZE);
  83         if (ret != 0 && ret != -EEXIST)
  84                 goto fail;
  85         item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
  86                               struct btrfs_csum_item);
  87         ret = 0;
  88         ret = btrfs_csum_data(root, data, len, item->csum);
  89         btrfs_mark_buffer_dirty(path->nodes[0]);
  90 fail:
  91         btrfs_release_path(root, path);
  92         btrfs_free_path(path);
  93         return ret;
  94 }
  95
  96 int btrfs_csum_verify_file_block(struct btrfs_root *root,
  97                                  u64 objectid, u64 offset,
  98                                  char *data, size_t len)
  99 {
 100         int ret;
 101         struct btrfs_key file_key;
 102         struct btrfs_path *path;
 103         struct btrfs_csum_item *item;
 104         char result[BTRFS_CSUM_SIZE];
 105
 106         path = btrfs_alloc_path();
 107         BUG_ON(!path);
 108         btrfs_init_path(path);
 109         file_key.objectid = objectid;
 110         file_key.offset = offset;
 111         file_key.flags = 0;
 112         btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
 113         mutex_lock(&root->fs_info->fs_mutex);
 114         ret = btrfs_search_slot(NULL, root, &file_key, path, 0, 0);
 115         if (ret)
 116                 goto fail;
 117         item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
 118                               struct btrfs_csum_item);
 119         ret = 0;
 120         ret = btrfs_csum_data(root, data, len, result);
 121         WARN_ON(ret);
 122         if (memcmp(result, item->csum, BTRFS_CSUM_SIZE))
 123                 ret = 1;
 124 fail:
 125         btrfs_release_path(root, path);
 126         btrfs_free_path(path);
 127         mutex_unlock(&root->fs_info->fs_mutex);
 128         return ret;
 129 }
 130