+
+/* Retrieve an inode from the filesystem. Eventually this will be a cache and
+ * so we might need to go fetch the inode from elsewhere; for now all
+ * filesystem state is stored here. */
+BlueSkyInode *bluesky_get_inode(BlueSkyFS *fs, uint64_t inum)
+{
+ BlueSkyInode *inode = NULL;
+
+ g_mutex_lock(fs->lock);
+ inode = (BlueSkyInode *)g_hash_table_lookup(fs->inodes, &inum);
+ g_mutex_unlock(fs->lock);
+
+ return inode;
+}
+
+/* Insert an inode into the filesystem inode cache. */
+void bluesky_insert_inode(BlueSkyFS *fs, BlueSkyInode *inode)
+{
+ g_mutex_lock(fs->lock);
+ g_hash_table_insert(fs->inodes, &inode->inum, inode);
+ g_mutex_unlock(fs->lock);
+}
+
+/* Set the size of a file. This will truncate or extend the file as needed.
+ * Newly-allocated bytes are zeroed. */
+void bluesky_file_truncate(BlueSkyInode *inode, uint64_t size)
+{
+ g_return_if_fail(size <= BLUESKY_MAX_FILE_SIZE);
+
+ if (size == inode->size)
+ return;
+
+ uint64_t blocks = (size + BLUESKY_BLOCK_SIZE - 1) / BLUESKY_MAX_FILE_SIZE;
+
+ if (blocks > inode->blocks->len) {
+ /* Need to add new blocks to the end of a file. New block structures
+ * are automatically zeroed, which initializes them to be pointers to
+ * zero blocks so we don't need to do any more work. */
+ g_array_set_size(inode->blocks, blocks);
+ } else if (blocks < inode->blocks->len) {
+ /* Delete blocks from a file. Must reclaim memory. */
+ for (guint i = inode->blocks->len; i < blocks; i++) {
+ BlueSkyBlock *b = &g_array_index(inode->blocks, BlueSkyBlock, i);
+ g_free(b->ref);
+ g_free(b->data);
+ }
+ g_array_set_size(inode->blocks, blocks);
+ }
+
+ /* TODO: Zero out partial blocks if needed? */
+
+ inode->size = size;
+ bluesky_inode_update_ctime(inode, 1);
+}