+ if (!this)
+ return EFI_INVALID_PARAMETER;
+ if (this->media->read_only)
+ return EFI_WRITE_PROTECTED;
+ /* TODO: check for media changes */
+ if (media_id != this->media->media_id)
+ return EFI_MEDIA_CHANGED;
+ if (!this->media->media_present)
+ return EFI_NO_MEDIA;
+ /* media->io_align is a power of 2 */
+ if ((uintptr_t)buffer & (this->media->io_align - 1))
+ return EFI_INVALID_PARAMETER;
+ if (lba * this->media->block_size + buffer_size >
+ this->media->last_block * this->media->block_size)
+ return EFI_INVALID_PARAMETER;
+