static int raw_pwrite(BlockDriverState *bs, int64_t offset, const uint8_t *buf, int count) { BDRVRawState *s = bs->opaque; int size, ret, shift, sum; sum = 0; if (s->aligned_buf != NULL) { if (offset & 0x1ff) { /* align offset on a 512 bytes boundary */ shift = offset & 0x1ff; ret = raw_pread_aligned(bs, offset - shift, s->aligned_buf, 512); if (ret < 0) return ret; size = 512 - shift; if (size > count) size = count; memcpy(s->aligned_buf + shift, buf, size); ret = raw_pwrite_aligned(bs, offset - shift, s->aligned_buf, 512); if (ret < 0) return ret; buf += size; offset += size; count -= size; sum += size; if (count == 0) return sum; } if (count & 0x1ff || (uintptr_t) buf & 0x1ff) { while ((size = (count & ~0x1ff)) != 0) { if (size > ALIGNED_BUFFER_SIZE) size = ALIGNED_BUFFER_SIZE; memcpy(s->aligned_buf, buf, size); ret = raw_pwrite_aligned(bs, offset, s->aligned_buf, size); if (ret < 0) return ret; buf += ret; offset += ret; count -= ret; sum += ret; } /* here, count < 512 because (count & ~0x1ff) == 0 */ if (count) { ret = raw_pread_aligned(bs, offset, s->aligned_buf, 512); if (ret < 0) return ret; memcpy(s->aligned_buf, buf, count); ret = raw_pwrite_aligned(bs, offset, s->aligned_buf, 512); if (ret < 0) return ret; if (count < ret) ret = count; sum += ret; } return sum; } } return raw_pwrite_aligned(bs, offset, buf, count) + sum; }