1078 lines
30 KiB
C
1078 lines
30 KiB
C
/*
|
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* Block driver for Hyper-V VHDX Images
|
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*
|
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* Copyright (c) 2013 Red Hat, Inc.,
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*
|
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* Authors:
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* Jeff Cody <jcody@redhat.com>
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*
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* This is based on the "VHDX Format Specification v1.00", published 8/25/2012
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* by Microsoft:
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* https://www.microsoft.com/en-us/download/details.aspx?id=34750
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*
|
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* This file covers the functionality of the metadata log writing, parsing, and
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* replay.
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*
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* This work is licensed under the terms of the GNU LGPL, version 2 or later.
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* See the COPYING.LIB file in the top-level directory.
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*
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*/
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#include "qemu/osdep.h"
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#include "qapi/error.h"
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#include "block/block_int.h"
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#include "qemu/error-report.h"
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#include "qemu/bswap.h"
|
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#include "qemu/memalign.h"
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#include "vhdx.h"
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|
|
|
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typedef struct VHDXLogSequence {
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bool valid;
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uint32_t count;
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VHDXLogEntries log;
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VHDXLogEntryHeader hdr;
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} VHDXLogSequence;
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typedef struct VHDXLogDescEntries {
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VHDXLogEntryHeader hdr;
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VHDXLogDescriptor desc[];
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} VHDXLogDescEntries;
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static const MSGUID zero_guid = { 0 };
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/* The log located on the disk is circular buffer containing
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* sectors of 4096 bytes each.
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*
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* It is assumed for the read/write functions below that the
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* circular buffer scheme uses a 'one sector open' to indicate
|
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* the buffer is full. Given the validation methods used for each
|
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* sector, this method should be compatible with other methods that
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* do not waste a sector.
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*/
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/* Allow peeking at the hdr entry at the beginning of the current
|
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* read index, without advancing the read index */
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static int vhdx_log_peek_hdr(BlockDriverState *bs, VHDXLogEntries *log,
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VHDXLogEntryHeader *hdr)
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|
{
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int ret = 0;
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uint64_t offset;
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uint32_t read;
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assert(hdr != NULL);
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/* peek is only supported on sector boundaries */
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if (log->read % VHDX_LOG_SECTOR_SIZE) {
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ret = -EFAULT;
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goto exit;
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}
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read = log->read;
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/* we are guaranteed that a) log sectors are 4096 bytes,
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* and b) the log length is a multiple of 1MB. So, there
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* is always a round number of sectors in the buffer */
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if ((read + sizeof(VHDXLogEntryHeader)) > log->length) {
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read = 0;
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}
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if (read == log->write) {
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ret = -EINVAL;
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goto exit;
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}
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offset = log->offset + read;
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ret = bdrv_pread(bs->file, offset, hdr, sizeof(VHDXLogEntryHeader));
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if (ret < 0) {
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goto exit;
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}
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vhdx_log_entry_hdr_le_import(hdr);
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exit:
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return ret;
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}
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/* Index increment for log, based on sector boundaries */
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static int vhdx_log_inc_idx(uint32_t idx, uint64_t length)
|
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{
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idx += VHDX_LOG_SECTOR_SIZE;
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/* we are guaranteed that a) log sectors are 4096 bytes,
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* and b) the log length is a multiple of 1MB. So, there
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* is always a round number of sectors in the buffer */
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return idx >= length ? 0 : idx;
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}
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/* Reset the log to empty */
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static void vhdx_log_reset(BlockDriverState *bs, BDRVVHDXState *s)
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{
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MSGUID guid = { 0 };
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s->log.read = s->log.write = 0;
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/* a log guid of 0 indicates an empty log to any parser of v0
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* VHDX logs */
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vhdx_update_headers(bs, s, false, &guid);
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}
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/* Reads num_sectors from the log (all log sectors are 4096 bytes),
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* into buffer 'buffer'. Upon return, *sectors_read will contain
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* the number of sectors successfully read.
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*
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* It is assumed that 'buffer' is already allocated, and of sufficient
|
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* size (i.e. >= 4096*num_sectors).
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*
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* If 'peek' is true, then the tail (read) pointer for the circular buffer is
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* not modified.
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*
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* 0 is returned on success, -errno otherwise. */
|
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static int vhdx_log_read_sectors(BlockDriverState *bs, VHDXLogEntries *log,
|
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uint32_t *sectors_read, void *buffer,
|
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uint32_t num_sectors, bool peek)
|
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{
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int ret = 0;
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uint64_t offset;
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uint32_t read;
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read = log->read;
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*sectors_read = 0;
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while (num_sectors) {
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if (read == log->write) {
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/* empty */
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break;
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}
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offset = log->offset + read;
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ret = bdrv_pread(bs->file, offset, buffer, VHDX_LOG_SECTOR_SIZE);
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if (ret < 0) {
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goto exit;
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}
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read = vhdx_log_inc_idx(read, log->length);
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*sectors_read = *sectors_read + 1;
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num_sectors--;
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}
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exit:
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if (!peek) {
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log->read = read;
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}
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return ret;
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}
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/* Writes num_sectors to the log (all log sectors are 4096 bytes),
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* from buffer 'buffer'. Upon return, *sectors_written will contain
|
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* the number of sectors successfully written.
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*
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* It is assumed that 'buffer' is at least 4096*num_sectors large.
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*
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* 0 is returned on success, -errno otherwise */
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static int vhdx_log_write_sectors(BlockDriverState *bs, VHDXLogEntries *log,
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uint32_t *sectors_written, void *buffer,
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uint32_t num_sectors)
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{
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int ret = 0;
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uint64_t offset;
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uint32_t write;
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void *buffer_tmp;
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BDRVVHDXState *s = bs->opaque;
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ret = vhdx_user_visible_write(bs, s);
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if (ret < 0) {
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goto exit;
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}
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write = log->write;
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buffer_tmp = buffer;
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while (num_sectors) {
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offset = log->offset + write;
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write = vhdx_log_inc_idx(write, log->length);
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if (write == log->read) {
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/* full */
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break;
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}
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ret = bdrv_pwrite(bs->file, offset, buffer_tmp,
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VHDX_LOG_SECTOR_SIZE);
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if (ret < 0) {
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goto exit;
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}
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buffer_tmp += VHDX_LOG_SECTOR_SIZE;
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log->write = write;
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*sectors_written = *sectors_written + 1;
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num_sectors--;
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}
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exit:
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return ret;
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}
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/* Validates a log entry header */
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static bool vhdx_log_hdr_is_valid(VHDXLogEntries *log, VHDXLogEntryHeader *hdr,
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BDRVVHDXState *s)
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{
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int valid = false;
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if (hdr->signature != VHDX_LOG_SIGNATURE) {
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goto exit;
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}
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/* if the individual entry length is larger than the whole log
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* buffer, that is obviously invalid */
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if (log->length < hdr->entry_length) {
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goto exit;
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}
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/* length of entire entry must be in units of 4KB (log sector size) */
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if (hdr->entry_length % (VHDX_LOG_SECTOR_SIZE)) {
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goto exit;
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}
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/* per spec, sequence # must be > 0 */
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if (hdr->sequence_number == 0) {
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goto exit;
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}
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/* log entries are only valid if they match the file-wide log guid
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* found in the active header */
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if (!guid_eq(hdr->log_guid, s->headers[s->curr_header]->log_guid)) {
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goto exit;
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}
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if (hdr->descriptor_count * sizeof(VHDXLogDescriptor) > hdr->entry_length) {
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goto exit;
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}
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valid = true;
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exit:
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return valid;
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}
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/*
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* Given a log header, this will validate that the descriptors and the
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* corresponding data sectors (if applicable)
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*
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* Validation consists of:
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* 1. Making sure the sequence numbers matches the entry header
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* 2. Verifying a valid signature ('zero' or 'desc' for descriptors)
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* 3. File offset field is a multiple of 4KB
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* 4. If a data descriptor, the corresponding data sector
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* has its signature ('data') and matching sequence number
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*
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* @desc: the data buffer containing the descriptor
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* @hdr: the log entry header
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*
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* Returns true if valid
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*/
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static bool vhdx_log_desc_is_valid(VHDXLogDescriptor *desc,
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VHDXLogEntryHeader *hdr)
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{
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bool ret = false;
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if (desc->sequence_number != hdr->sequence_number) {
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goto exit;
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}
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if (desc->file_offset % VHDX_LOG_SECTOR_SIZE) {
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goto exit;
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}
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if (desc->signature == VHDX_LOG_ZERO_SIGNATURE) {
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if (desc->zero_length % VHDX_LOG_SECTOR_SIZE == 0) {
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/* valid */
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ret = true;
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}
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} else if (desc->signature == VHDX_LOG_DESC_SIGNATURE) {
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/* valid */
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ret = true;
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}
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exit:
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return ret;
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}
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|
|
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/* Prior to sector data for a log entry, there is the header
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* and the descriptors referenced in the header:
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*
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* [] = 4KB sector
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*
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* [ hdr, desc ][ desc ][ ... ][ data ][ ... ]
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*
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* The first sector in a log entry has a 64 byte header, and
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* up to 126 32-byte descriptors. If more descriptors than
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* 126 are required, then subsequent sectors can have up to 128
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* descriptors. Each sector is 4KB. Data follows the descriptor
|
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* sectors.
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*
|
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* This will return the number of sectors needed to encompass
|
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* the passed number of descriptors in desc_cnt.
|
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*
|
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* This will never return 0, even if desc_cnt is 0.
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*/
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static int vhdx_compute_desc_sectors(uint32_t desc_cnt)
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{
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uint32_t desc_sectors;
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desc_cnt += 2; /* account for header in first sector */
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desc_sectors = desc_cnt / 128;
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if (desc_cnt % 128) {
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desc_sectors++;
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}
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return desc_sectors;
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}
|
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|
|
|
|
/* Reads the log header, and subsequent descriptors (if any). This
|
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* will allocate all the space for buffer, which must be NULL when
|
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* passed into this function. Each descriptor will also be validated,
|
|
* and error returned if any are invalid. */
|
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static int vhdx_log_read_desc(BlockDriverState *bs, BDRVVHDXState *s,
|
|
VHDXLogEntries *log, VHDXLogDescEntries **buffer,
|
|
bool convert_endian)
|
|
{
|
|
int ret = 0;
|
|
uint32_t desc_sectors;
|
|
uint32_t sectors_read;
|
|
VHDXLogEntryHeader hdr;
|
|
VHDXLogDescEntries *desc_entries = NULL;
|
|
VHDXLogDescriptor desc;
|
|
int i;
|
|
|
|
assert(*buffer == NULL);
|
|
|
|
ret = vhdx_log_peek_hdr(bs, log, &hdr);
|
|
if (ret < 0) {
|
|
goto exit;
|
|
}
|
|
|
|
if (vhdx_log_hdr_is_valid(log, &hdr, s) == false) {
|
|
ret = -EINVAL;
|
|
goto exit;
|
|
}
|
|
|
|
desc_sectors = vhdx_compute_desc_sectors(hdr.descriptor_count);
|
|
desc_entries = qemu_try_blockalign(bs->file->bs,
|
|
desc_sectors * VHDX_LOG_SECTOR_SIZE);
|
|
if (desc_entries == NULL) {
|
|
ret = -ENOMEM;
|
|
goto exit;
|
|
}
|
|
|
|
ret = vhdx_log_read_sectors(bs, log, §ors_read, desc_entries,
|
|
desc_sectors, false);
|
|
if (ret < 0) {
|
|
goto free_and_exit;
|
|
}
|
|
if (sectors_read != desc_sectors) {
|
|
ret = -EINVAL;
|
|
goto free_and_exit;
|
|
}
|
|
|
|
/* put in proper endianness, and validate each desc */
|
|
for (i = 0; i < hdr.descriptor_count; i++) {
|
|
desc = desc_entries->desc[i];
|
|
vhdx_log_desc_le_import(&desc);
|
|
if (convert_endian) {
|
|
desc_entries->desc[i] = desc;
|
|
}
|
|
if (vhdx_log_desc_is_valid(&desc, &hdr) == false) {
|
|
ret = -EINVAL;
|
|
goto free_and_exit;
|
|
}
|
|
}
|
|
if (convert_endian) {
|
|
desc_entries->hdr = hdr;
|
|
}
|
|
|
|
*buffer = desc_entries;
|
|
goto exit;
|
|
|
|
free_and_exit:
|
|
qemu_vfree(desc_entries);
|
|
exit:
|
|
return ret;
|
|
}
|
|
|
|
|
|
/* Flushes the descriptor described by desc to the VHDX image file.
|
|
* If the descriptor is a data descriptor, than 'data' must be non-NULL,
|
|
* and >= 4096 bytes (VHDX_LOG_SECTOR_SIZE), containing the data to be
|
|
* written.
|
|
*
|
|
* Verification is performed to make sure the sequence numbers of a data
|
|
* descriptor match the sequence number in the desc.
|
|
*
|
|
* For a zero descriptor, it may describe multiple sectors to fill with zeroes.
|
|
* In this case, it should be noted that zeroes are written to disk, and the
|
|
* image file is not extended as a sparse file. */
|
|
static int vhdx_log_flush_desc(BlockDriverState *bs, VHDXLogDescriptor *desc,
|
|
VHDXLogDataSector *data)
|
|
{
|
|
int ret = 0;
|
|
uint64_t seq, file_offset;
|
|
uint32_t offset = 0;
|
|
void *buffer = NULL;
|
|
uint64_t count = 1;
|
|
int i;
|
|
|
|
buffer = qemu_blockalign(bs, VHDX_LOG_SECTOR_SIZE);
|
|
|
|
if (desc->signature == VHDX_LOG_DESC_SIGNATURE) {
|
|
/* data sector */
|
|
if (data == NULL) {
|
|
ret = -EFAULT;
|
|
goto exit;
|
|
}
|
|
|
|
/* The sequence number of the data sector must match that
|
|
* in the descriptor */
|
|
seq = data->sequence_high;
|
|
seq <<= 32;
|
|
seq |= data->sequence_low & 0xffffffff;
|
|
|
|
if (seq != desc->sequence_number) {
|
|
ret = -EINVAL;
|
|
goto exit;
|
|
}
|
|
|
|
/* Each data sector is in total 4096 bytes, however the first
|
|
* 8 bytes, and last 4 bytes, are located in the descriptor */
|
|
memcpy(buffer, &desc->leading_bytes, 8);
|
|
offset += 8;
|
|
|
|
memcpy(buffer+offset, data->data, 4084);
|
|
offset += 4084;
|
|
|
|
memcpy(buffer+offset, &desc->trailing_bytes, 4);
|
|
|
|
} else if (desc->signature == VHDX_LOG_ZERO_SIGNATURE) {
|
|
/* write 'count' sectors of sector */
|
|
memset(buffer, 0, VHDX_LOG_SECTOR_SIZE);
|
|
count = desc->zero_length / VHDX_LOG_SECTOR_SIZE;
|
|
} else {
|
|
error_report("Invalid VHDX log descriptor entry signature 0x%" PRIx32,
|
|
desc->signature);
|
|
ret = -EINVAL;
|
|
goto exit;
|
|
}
|
|
|
|
file_offset = desc->file_offset;
|
|
|
|
/* count is only > 1 if we are writing zeroes */
|
|
for (i = 0; i < count; i++) {
|
|
ret = bdrv_pwrite_sync(bs->file, file_offset, buffer,
|
|
VHDX_LOG_SECTOR_SIZE);
|
|
if (ret < 0) {
|
|
goto exit;
|
|
}
|
|
file_offset += VHDX_LOG_SECTOR_SIZE;
|
|
}
|
|
|
|
exit:
|
|
qemu_vfree(buffer);
|
|
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;
|
|
int64_t file_length;
|
|
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;
|
|
}
|
|
file_length = bdrv_getlength(bs->file->bs);
|
|
if (file_length < 0) {
|
|
ret = file_length;
|
|
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 > file_length) {
|
|
ret = -EINVAL;
|
|
goto exit;
|
|
}
|
|
|
|
ret = vhdx_log_read_desc(bs, s, &logs->log, &desc_entries, true);
|
|
if (ret < 0) {
|
|
goto exit;
|
|
}
|
|
|
|
for (i = 0; i < desc_entries->hdr.descriptor_count; i++) {
|
|
if (desc_entries->desc[i].signature == VHDX_LOG_DESC_SIGNATURE) {
|
|
/* 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;
|
|
}
|
|
vhdx_log_data_le_import(data);
|
|
}
|
|
|
|
ret = vhdx_log_flush_desc(bs, &desc_entries->desc[i], data);
|
|
if (ret < 0) {
|
|
goto exit;
|
|
}
|
|
}
|
|
if (file_length < desc_entries->hdr.last_file_offset) {
|
|
new_file_size = desc_entries->hdr.last_file_offset;
|
|
if (new_file_size % (1 * MiB)) {
|
|
/* round up to nearest 1MB boundary */
|
|
new_file_size = QEMU_ALIGN_UP(new_file_size, MiB);
|
|
if (new_file_size > INT64_MAX) {
|
|
ret = -EINVAL;
|
|
goto exit;
|
|
}
|
|
ret = bdrv_truncate(bs->file, new_file_size, false,
|
|
PREALLOC_MODE_OFF, 0, NULL);
|
|
if (ret < 0) {
|
|
goto exit;
|
|
}
|
|
}
|
|
}
|
|
qemu_vfree(desc_entries);
|
|
desc_entries = NULL;
|
|
}
|
|
|
|
ret = bdrv_flush(bs);
|
|
if (ret < 0) {
|
|
goto exit;
|
|
}
|
|
/* once the log is fully flushed, indicate that we have an empty log
|
|
* now. This also sets the log guid to 0, to indicate an empty log */
|
|
vhdx_log_reset(bs, s);
|
|
|
|
exit:
|
|
qemu_vfree(data);
|
|
qemu_vfree(desc_entries);
|
|
return ret;
|
|
}
|
|
|
|
static int vhdx_validate_log_entry(BlockDriverState *bs, BDRVVHDXState *s,
|
|
VHDXLogEntries *log, uint64_t seq,
|
|
bool *valid, VHDXLogEntryHeader *entry)
|
|
{
|
|
int ret = 0;
|
|
VHDXLogEntryHeader hdr;
|
|
void *buffer = NULL;
|
|
uint32_t i, desc_sectors, total_sectors, crc;
|
|
uint32_t sectors_read = 0;
|
|
VHDXLogDescEntries *desc_buffer = NULL;
|
|
|
|
*valid = false;
|
|
|
|
ret = vhdx_log_peek_hdr(bs, log, &hdr);
|
|
if (ret < 0) {
|
|
goto inc_and_exit;
|
|
}
|
|
|
|
if (vhdx_log_hdr_is_valid(log, &hdr, s) == false) {
|
|
goto inc_and_exit;
|
|
}
|
|
|
|
if (seq > 0) {
|
|
if (hdr.sequence_number != seq + 1) {
|
|
goto inc_and_exit;
|
|
}
|
|
}
|
|
|
|
desc_sectors = vhdx_compute_desc_sectors(hdr.descriptor_count);
|
|
|
|
/* Read all log sectors, and calculate log checksum */
|
|
|
|
total_sectors = hdr.entry_length / VHDX_LOG_SECTOR_SIZE;
|
|
|
|
|
|
/* read_desc() will increment the read idx */
|
|
ret = vhdx_log_read_desc(bs, s, log, &desc_buffer, false);
|
|
if (ret < 0) {
|
|
goto free_and_exit;
|
|
}
|
|
|
|
crc = vhdx_checksum_calc(0xffffffff, (void *)desc_buffer,
|
|
desc_sectors * VHDX_LOG_SECTOR_SIZE, 4);
|
|
crc ^= 0xffffffff;
|
|
|
|
buffer = qemu_blockalign(bs, VHDX_LOG_SECTOR_SIZE);
|
|
if (total_sectors > desc_sectors) {
|
|
for (i = 0; i < total_sectors - desc_sectors; i++) {
|
|
sectors_read = 0;
|
|
ret = vhdx_log_read_sectors(bs, log, §ors_read, buffer,
|
|
1, false);
|
|
if (ret < 0 || sectors_read != 1) {
|
|
goto free_and_exit;
|
|
}
|
|
crc = vhdx_checksum_calc(crc, buffer, VHDX_LOG_SECTOR_SIZE, -1);
|
|
crc ^= 0xffffffff;
|
|
}
|
|
}
|
|
crc ^= 0xffffffff;
|
|
if (crc != hdr.checksum) {
|
|
goto free_and_exit;
|
|
}
|
|
|
|
*valid = true;
|
|
*entry = hdr;
|
|
goto free_and_exit;
|
|
|
|
inc_and_exit:
|
|
log->read = vhdx_log_inc_idx(log->read, log->length);
|
|
|
|
free_and_exit:
|
|
qemu_vfree(buffer);
|
|
qemu_vfree(desc_buffer);
|
|
return ret;
|
|
}
|
|
|
|
/* Search through the log circular buffer, and find the valid, active
|
|
* log sequence, if any exists
|
|
* */
|
|
static int vhdx_log_search(BlockDriverState *bs, BDRVVHDXState *s,
|
|
VHDXLogSequence *logs)
|
|
{
|
|
int ret = 0;
|
|
uint32_t tail;
|
|
bool seq_valid = false;
|
|
VHDXLogSequence candidate = { 0 };
|
|
VHDXLogEntryHeader hdr = { 0 };
|
|
VHDXLogEntries curr_log;
|
|
|
|
memcpy(&curr_log, &s->log, sizeof(VHDXLogEntries));
|
|
curr_log.write = curr_log.length; /* assume log is full */
|
|
curr_log.read = 0;
|
|
|
|
|
|
/* now we will go through the whole log sector by sector, until
|
|
* we find a valid, active log sequence, or reach the end of the
|
|
* log buffer */
|
|
for (;;) {
|
|
uint64_t curr_seq = 0;
|
|
VHDXLogSequence current = { 0 };
|
|
|
|
tail = curr_log.read;
|
|
|
|
ret = vhdx_validate_log_entry(bs, s, &curr_log, curr_seq,
|
|
&seq_valid, &hdr);
|
|
if (ret < 0) {
|
|
goto exit;
|
|
}
|
|
|
|
if (seq_valid) {
|
|
current.valid = true;
|
|
current.log = curr_log;
|
|
current.log.read = tail;
|
|
current.log.write = curr_log.read;
|
|
current.count = 1;
|
|
current.hdr = hdr;
|
|
|
|
|
|
for (;;) {
|
|
ret = vhdx_validate_log_entry(bs, s, &curr_log, curr_seq,
|
|
&seq_valid, &hdr);
|
|
if (ret < 0) {
|
|
goto exit;
|
|
}
|
|
if (seq_valid == false) {
|
|
break;
|
|
}
|
|
current.log.write = curr_log.read;
|
|
current.count++;
|
|
|
|
curr_seq = hdr.sequence_number;
|
|
}
|
|
}
|
|
|
|
if (current.valid) {
|
|
if (candidate.valid == false ||
|
|
current.hdr.sequence_number > candidate.hdr.sequence_number) {
|
|
candidate = current;
|
|
}
|
|
}
|
|
|
|
if (curr_log.read < tail) {
|
|
break;
|
|
}
|
|
}
|
|
|
|
*logs = candidate;
|
|
|
|
if (candidate.valid) {
|
|
/* this is the next sequence number, for writes */
|
|
s->log.sequence = candidate.hdr.sequence_number + 1;
|
|
}
|
|
|
|
|
|
exit:
|
|
return ret;
|
|
}
|
|
|
|
/* Parse the replay log. Per the VHDX spec, if the log is present
|
|
* it must be replayed prior to opening the file, even read-only.
|
|
*
|
|
* If read-only, we must replay the log in RAM (or refuse to open
|
|
* a dirty VHDX file read-only) */
|
|
int vhdx_parse_log(BlockDriverState *bs, BDRVVHDXState *s, bool *flushed,
|
|
Error **errp)
|
|
{
|
|
int ret = 0;
|
|
VHDXHeader *hdr;
|
|
VHDXLogSequence logs = { 0 };
|
|
|
|
hdr = s->headers[s->curr_header];
|
|
|
|
*flushed = false;
|
|
|
|
/* s->log.hdr is freed in vhdx_close() */
|
|
if (s->log.hdr == NULL) {
|
|
s->log.hdr = qemu_blockalign(bs, sizeof(VHDXLogEntryHeader));
|
|
}
|
|
|
|
s->log.offset = hdr->log_offset;
|
|
s->log.length = hdr->log_length;
|
|
|
|
if (s->log.offset < VHDX_LOG_MIN_SIZE ||
|
|
s->log.offset % VHDX_LOG_MIN_SIZE) {
|
|
ret = -EINVAL;
|
|
goto exit;
|
|
}
|
|
|
|
/* per spec, only log version of 0 is supported */
|
|
if (hdr->log_version != 0) {
|
|
ret = -EINVAL;
|
|
goto exit;
|
|
}
|
|
|
|
/* If either the log guid, or log length is zero,
|
|
* then a replay log is not present */
|
|
if (guid_eq(hdr->log_guid, zero_guid)) {
|
|
goto exit;
|
|
}
|
|
|
|
if (hdr->log_length == 0) {
|
|
goto exit;
|
|
}
|
|
|
|
if (hdr->log_length % VHDX_LOG_MIN_SIZE) {
|
|
ret = -EINVAL;
|
|
goto exit;
|
|
}
|
|
|
|
|
|
/* The log is present, we need to find if and where there is an active
|
|
* sequence of valid entries present in the log. */
|
|
|
|
ret = vhdx_log_search(bs, s, &logs);
|
|
if (ret < 0) {
|
|
goto exit;
|
|
}
|
|
|
|
if (logs.valid) {
|
|
if (bdrv_is_read_only(bs)) {
|
|
bdrv_refresh_filename(bs);
|
|
ret = -EPERM;
|
|
error_setg(errp,
|
|
"VHDX image file '%s' opened read-only, but "
|
|
"contains a log that needs to be replayed",
|
|
bs->filename);
|
|
error_append_hint(errp, "To replay the log, run:\n"
|
|
"qemu-img check -r all '%s'\n",
|
|
bs->filename);
|
|
goto exit;
|
|
}
|
|
/* now flush the log */
|
|
ret = vhdx_log_flush(bs, s, &logs);
|
|
if (ret < 0) {
|
|
goto exit;
|
|
}
|
|
*flushed = true;
|
|
}
|
|
|
|
|
|
exit:
|
|
return ret;
|
|
}
|
|
|
|
|
|
|
|
static void vhdx_log_raw_to_le_sector(VHDXLogDescriptor *desc,
|
|
VHDXLogDataSector *sector, void *data,
|
|
uint64_t seq)
|
|
{
|
|
/* 8 + 4084 + 4 = 4096, 1 log sector */
|
|
memcpy(&desc->leading_bytes, data, 8);
|
|
data += 8;
|
|
desc->leading_bytes = cpu_to_le64(desc->leading_bytes);
|
|
memcpy(sector->data, data, 4084);
|
|
data += 4084;
|
|
memcpy(&desc->trailing_bytes, data, 4);
|
|
desc->trailing_bytes = cpu_to_le32(desc->trailing_bytes);
|
|
data += 4;
|
|
|
|
sector->sequence_high = (uint32_t) (seq >> 32);
|
|
sector->sequence_low = (uint32_t) (seq & 0xffffffff);
|
|
sector->data_signature = VHDX_LOG_DATA_SIGNATURE;
|
|
|
|
vhdx_log_desc_le_export(desc);
|
|
vhdx_log_data_le_export(sector);
|
|
}
|
|
|
|
|
|
static int vhdx_log_write(BlockDriverState *bs, BDRVVHDXState *s,
|
|
void *data, uint32_t length, uint64_t offset)
|
|
{
|
|
int ret = 0;
|
|
void *buffer = NULL;
|
|
void *merged_sector = NULL;
|
|
void *data_tmp, *sector_write;
|
|
unsigned int i;
|
|
int sector_offset;
|
|
uint32_t desc_sectors, sectors, total_length;
|
|
uint32_t sectors_written = 0;
|
|
uint32_t aligned_length;
|
|
uint32_t leading_length = 0;
|
|
uint32_t trailing_length = 0;
|
|
uint32_t partial_sectors = 0;
|
|
uint32_t bytes_written = 0;
|
|
uint64_t file_offset;
|
|
int64_t file_length;
|
|
VHDXHeader *header;
|
|
VHDXLogEntryHeader new_hdr;
|
|
VHDXLogDescriptor *new_desc = NULL;
|
|
VHDXLogDataSector *data_sector = NULL;
|
|
MSGUID new_guid = { 0 };
|
|
|
|
header = s->headers[s->curr_header];
|
|
|
|
/* need to have offset read data, and be on 4096 byte boundary */
|
|
|
|
if (length > header->log_length) {
|
|
/* no log present. we could create a log here instead of failing */
|
|
ret = -EINVAL;
|
|
goto exit;
|
|
}
|
|
|
|
if (guid_eq(header->log_guid, zero_guid)) {
|
|
vhdx_guid_generate(&new_guid);
|
|
vhdx_update_headers(bs, s, false, &new_guid);
|
|
} else {
|
|
/* currently, we require that the log be flushed after
|
|
* every write. */
|
|
ret = -ENOTSUP;
|
|
goto exit;
|
|
}
|
|
|
|
/* 0 is an invalid sequence number, but may also represent the first
|
|
* log write (or a wrapped seq) */
|
|
if (s->log.sequence == 0) {
|
|
s->log.sequence = 1;
|
|
}
|
|
|
|
sector_offset = offset % VHDX_LOG_SECTOR_SIZE;
|
|
file_offset = QEMU_ALIGN_DOWN(offset, VHDX_LOG_SECTOR_SIZE);
|
|
|
|
aligned_length = length;
|
|
|
|
/* add in the unaligned head and tail bytes */
|
|
if (sector_offset) {
|
|
leading_length = (VHDX_LOG_SECTOR_SIZE - sector_offset);
|
|
leading_length = leading_length > length ? length : leading_length;
|
|
aligned_length -= leading_length;
|
|
partial_sectors++;
|
|
}
|
|
|
|
sectors = aligned_length / VHDX_LOG_SECTOR_SIZE;
|
|
trailing_length = aligned_length - (sectors * VHDX_LOG_SECTOR_SIZE);
|
|
if (trailing_length) {
|
|
partial_sectors++;
|
|
}
|
|
|
|
sectors += partial_sectors;
|
|
|
|
file_length = bdrv_getlength(bs->file->bs);
|
|
if (file_length < 0) {
|
|
ret = file_length;
|
|
goto exit;
|
|
}
|
|
|
|
/* sectors is now how many sectors the data itself takes, not
|
|
* including the header and descriptor metadata */
|
|
|
|
new_hdr = (VHDXLogEntryHeader) {
|
|
.signature = VHDX_LOG_SIGNATURE,
|
|
.tail = s->log.tail,
|
|
.sequence_number = s->log.sequence,
|
|
.descriptor_count = sectors,
|
|
.reserved = 0,
|
|
.flushed_file_offset = file_length,
|
|
.last_file_offset = file_length,
|
|
.log_guid = header->log_guid,
|
|
};
|
|
|
|
|
|
desc_sectors = vhdx_compute_desc_sectors(new_hdr.descriptor_count);
|
|
|
|
total_length = (desc_sectors + sectors) * VHDX_LOG_SECTOR_SIZE;
|
|
new_hdr.entry_length = total_length;
|
|
|
|
vhdx_log_entry_hdr_le_export(&new_hdr);
|
|
|
|
buffer = qemu_blockalign(bs, total_length);
|
|
memcpy(buffer, &new_hdr, sizeof(new_hdr));
|
|
|
|
new_desc = buffer + sizeof(new_hdr);
|
|
data_sector = buffer + (desc_sectors * VHDX_LOG_SECTOR_SIZE);
|
|
data_tmp = data;
|
|
|
|
/* All log sectors are 4KB, so for any partial sectors we must
|
|
* merge the data with preexisting data from the final file
|
|
* destination */
|
|
merged_sector = qemu_blockalign(bs, VHDX_LOG_SECTOR_SIZE);
|
|
|
|
for (i = 0; i < sectors; i++) {
|
|
new_desc->signature = VHDX_LOG_DESC_SIGNATURE;
|
|
new_desc->sequence_number = s->log.sequence;
|
|
new_desc->file_offset = file_offset;
|
|
|
|
if (i == 0 && leading_length) {
|
|
/* partial sector at the front of the buffer */
|
|
ret = bdrv_pread(bs->file, file_offset, merged_sector,
|
|
VHDX_LOG_SECTOR_SIZE);
|
|
if (ret < 0) {
|
|
goto exit;
|
|
}
|
|
memcpy(merged_sector + sector_offset, data_tmp, leading_length);
|
|
bytes_written = leading_length;
|
|
sector_write = merged_sector;
|
|
} else if (i == sectors - 1 && trailing_length) {
|
|
/* partial sector at the end of the buffer */
|
|
ret = bdrv_pread(bs->file,
|
|
file_offset,
|
|
merged_sector + trailing_length,
|
|
VHDX_LOG_SECTOR_SIZE - trailing_length);
|
|
if (ret < 0) {
|
|
goto exit;
|
|
}
|
|
memcpy(merged_sector, data_tmp, trailing_length);
|
|
bytes_written = trailing_length;
|
|
sector_write = merged_sector;
|
|
} else {
|
|
bytes_written = VHDX_LOG_SECTOR_SIZE;
|
|
sector_write = data_tmp;
|
|
}
|
|
|
|
/* populate the raw sector data into the proper structures,
|
|
* as well as update the descriptor, and convert to proper
|
|
* endianness */
|
|
vhdx_log_raw_to_le_sector(new_desc, data_sector, sector_write,
|
|
s->log.sequence);
|
|
|
|
data_tmp += bytes_written;
|
|
data_sector++;
|
|
new_desc++;
|
|
file_offset += VHDX_LOG_SECTOR_SIZE;
|
|
}
|
|
|
|
/* checksum covers entire entry, from the log header through the
|
|
* last data sector */
|
|
vhdx_update_checksum(buffer, total_length,
|
|
offsetof(VHDXLogEntryHeader, checksum));
|
|
|
|
/* now write to the log */
|
|
ret = vhdx_log_write_sectors(bs, &s->log, §ors_written, buffer,
|
|
desc_sectors + sectors);
|
|
if (ret < 0) {
|
|
goto exit;
|
|
}
|
|
|
|
if (sectors_written != desc_sectors + sectors) {
|
|
/* instead of failing, we could flush the log here */
|
|
ret = -EINVAL;
|
|
goto exit;
|
|
}
|
|
|
|
s->log.sequence++;
|
|
/* write new tail */
|
|
s->log.tail = s->log.write;
|
|
|
|
exit:
|
|
qemu_vfree(buffer);
|
|
qemu_vfree(merged_sector);
|
|
return ret;
|
|
}
|
|
|
|
/* Perform a log write, and then immediately flush the entire log */
|
|
int vhdx_log_write_and_flush(BlockDriverState *bs, BDRVVHDXState *s,
|
|
void *data, uint32_t length, uint64_t offset)
|
|
{
|
|
int ret = 0;
|
|
VHDXLogSequence logs = { .valid = true,
|
|
.count = 1,
|
|
.hdr = { 0 } };
|
|
|
|
|
|
/* Make sure data written (new and/or changed blocks) is stable
|
|
* on disk, before creating log entry */
|
|
ret = bdrv_flush(bs);
|
|
if (ret < 0) {
|
|
goto exit;
|
|
}
|
|
|
|
ret = vhdx_log_write(bs, s, data, length, offset);
|
|
if (ret < 0) {
|
|
goto exit;
|
|
}
|
|
logs.log = s->log;
|
|
|
|
/* Make sure log is stable on disk */
|
|
ret = bdrv_flush(bs);
|
|
if (ret < 0) {
|
|
goto exit;
|
|
}
|
|
|
|
ret = vhdx_log_flush(bs, s, &logs);
|
|
if (ret < 0) {
|
|
goto exit;
|
|
}
|
|
|
|
s->log = logs.log;
|
|
|
|
exit:
|
|
return ret;
|
|
}
|
|
|