/* Writes num_sectors to the log (all log sectors are 4096 bytes),
* from buffer 'buffer'. Upon return, *sectors_written will contain
* the number of sectors successfully written.
*
* It is assumed that 'buffer' is at least 4096*num_sectors large.
*
* 0 is returned on success, -errno otherwise */
static int vhdx_log_write_sectors(BlockDriverState *bs, VHDXLogEntries *log,
uint32_t *sectors_written, void *buffer,
uint32_t num_sectors)
{
int ret = 0;
uint64_t offset;
uint32_t write;
void *buffer_tmp;
BDRVVHDXState *s = bs->opaque;
ret = vhdx_user_visible_write(bs, s);
if (ret < 0) {
goto exit;
}
write = log->write;
buffer_tmp = buffer;
while (num_sectors) {
offset = log->offset + write;
write = vhdx_log_inc_idx(write, log->length);
if (write == log->read) {
/* full */
break;
}
ret = bdrv_pwrite(bs->file->bs, offset, buffer_tmp,
VHDX_LOG_SECTOR_SIZE);
if (ret < 0) {
goto exit;
}
buffer_tmp += VHDX_LOG_SECTOR_SIZE;
log->write = write;
*sectors_written = *sectors_written + 1;
num_sectors--;
}
exit:
return ret;
}
/* Flush the entire log (as described by 'logs') to the VHDX image
* file, and then set the log to 'empty' status once complete.
*
* The log entries should be validate prior to flushing */
static int vhdx_log_flush(BlockDriverState *bs, BDRVVHDXState *s,
VHDXLogSequence *logs)
{
int ret = 0;
int i;
uint32_t cnt, sectors_read;
uint64_t new_file_size;
void *data = NULL;
VHDXLogDescEntries *desc_entries = NULL;
VHDXLogEntryHeader hdr_tmp = { 0 };
cnt = logs->count;
data = qemu_blockalign(bs, VHDX_LOG_SECTOR_SIZE);
ret = vhdx_user_visible_write(bs, s);
if (ret < 0) {
goto exit;
}
/* each iteration represents one log sequence, which may span multiple
* sectors */
while (cnt--) {
ret = vhdx_log_peek_hdr(bs, &logs->log, &hdr_tmp);
if (ret < 0) {
goto exit;
}
/* if the log shows a FlushedFileOffset larger than our current file
* size, then that means the file has been truncated / corrupted, and
* we must refused to open it / use it */
if (hdr_tmp.flushed_file_offset > bdrv_getlength(bs->file)) {
ret = -EINVAL;
goto exit;
}
ret = vhdx_log_read_desc(bs, s, &logs->log, &desc_entries);
if (ret < 0) {
goto exit;
}
for (i = 0; i < desc_entries->hdr.descriptor_count; i++) {
if (!memcmp(&desc_entries->desc[i].signature, "desc", 4)) {
/* data sector, so read a sector to flush */
ret = vhdx_log_read_sectors(bs, &logs->log, §ors_read,
data, 1, false);
if (ret < 0) {
goto exit;
}
if (sectors_read != 1) {
ret = -EINVAL;
goto exit;
}
}
ret = vhdx_log_flush_desc(bs, &desc_entries->desc[i], data);
if (ret < 0) {
goto exit;
}
}
if (bdrv_getlength(bs->file) < desc_entries->hdr.last_file_offset) {
new_file_size = desc_entries->hdr.last_file_offset;
if (new_file_size % (1024*1024)) {
/* round up to nearest 1MB boundary */
new_file_size = ((new_file_size >> 20) + 1) << 20;
bdrv_truncate(bs->file, new_file_size);
}
}
