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/*
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* QEMU live block migration
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*
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* Copyright IBM, Corp. 2009
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*
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* Authors:
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* Liran Schour <lirans@il.ibm.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*
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*/
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#include "qemu-common.h" |
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#include "block_int.h" |
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#include "hw/hw.h" |
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#include "qemu-queue.h" |
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#include "monitor.h" |
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#include "block-migration.h" |
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#include <assert.h> |
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#define BLOCK_SIZE (BDRV_SECTORS_PER_DIRTY_CHUNK << BDRV_SECTOR_BITS)
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#define BLK_MIG_FLAG_DEVICE_BLOCK 0x01 |
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#define BLK_MIG_FLAG_EOS 0x02 |
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#define BLK_MIG_FLAG_PROGRESS 0x04 |
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|
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#define MAX_IS_ALLOCATED_SEARCH 65536 |
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//#define DEBUG_BLK_MIGRATION
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#ifdef DEBUG_BLK_MIGRATION
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#define DPRINTF(fmt, ...) \
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do { printf("blk_migration: " fmt, ## __VA_ARGS__); } while (0) |
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#else
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#define DPRINTF(fmt, ...) \
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do { } while (0) |
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#endif
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typedef struct BlkMigDevState { |
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BlockDriverState *bs; |
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int bulk_completed;
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int shared_base;
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int64_t cur_sector; |
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int64_t cur_dirty; |
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int64_t completed_sectors; |
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int64_t total_sectors; |
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int64_t dirty; |
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QSIMPLEQ_ENTRY(BlkMigDevState) entry; |
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} BlkMigDevState; |
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|
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typedef struct BlkMigBlock { |
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uint8_t *buf; |
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BlkMigDevState *bmds; |
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int64_t sector; |
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struct iovec iov;
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QEMUIOVector qiov; |
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BlockDriverAIOCB *aiocb; |
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int ret;
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QSIMPLEQ_ENTRY(BlkMigBlock) entry; |
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} BlkMigBlock; |
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typedef struct BlkMigState { |
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int blk_enable;
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int shared_base;
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QSIMPLEQ_HEAD(bmds_list, BlkMigDevState) bmds_list; |
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QSIMPLEQ_HEAD(blk_list, BlkMigBlock) blk_list; |
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int submitted;
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int read_done;
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int transferred;
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int64_t total_sector_sum; |
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int prev_progress;
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int bulk_completed;
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int dirty_iterations;
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} BlkMigState; |
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static BlkMigState block_mig_state;
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|
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static void blk_send(QEMUFile *f, BlkMigBlock * blk) |
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{ |
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int len;
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|
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/* sector number and flags */
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qemu_put_be64(f, (blk->sector << BDRV_SECTOR_BITS) |
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| BLK_MIG_FLAG_DEVICE_BLOCK); |
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/* device name */
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len = strlen(blk->bmds->bs->device_name); |
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qemu_put_byte(f, len); |
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qemu_put_buffer(f, (uint8_t *)blk->bmds->bs->device_name, len); |
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qemu_put_buffer(f, blk->buf, BLOCK_SIZE); |
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} |
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int blk_mig_active(void) |
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{ |
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return !QSIMPLEQ_EMPTY(&block_mig_state.bmds_list);
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} |
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uint64_t blk_mig_bytes_transferred(void)
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{ |
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BlkMigDevState *bmds; |
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uint64_t sum = 0;
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QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { |
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sum += bmds->completed_sectors; |
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} |
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return sum << BDRV_SECTOR_BITS;
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} |
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uint64_t blk_mig_bytes_remaining(void)
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{ |
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return blk_mig_bytes_total() - blk_mig_bytes_transferred();
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} |
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uint64_t blk_mig_bytes_total(void)
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{ |
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BlkMigDevState *bmds; |
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uint64_t sum = 0;
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QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { |
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sum += bmds->total_sectors; |
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} |
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return sum << BDRV_SECTOR_BITS;
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} |
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static void blk_mig_read_cb(void *opaque, int ret) |
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{ |
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BlkMigBlock *blk = opaque; |
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blk->ret = ret; |
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QSIMPLEQ_INSERT_TAIL(&block_mig_state.blk_list, blk, entry); |
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block_mig_state.submitted--; |
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block_mig_state.read_done++; |
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assert(block_mig_state.submitted >= 0);
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} |
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static int mig_save_device_bulk(Monitor *mon, QEMUFile *f, |
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BlkMigDevState *bmds) |
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{ |
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int64_t total_sectors = bmds->total_sectors; |
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int64_t cur_sector = bmds->cur_sector; |
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BlockDriverState *bs = bmds->bs; |
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BlkMigBlock *blk; |
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int nr_sectors;
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if (bmds->shared_base) {
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while (cur_sector < total_sectors &&
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!bdrv_is_allocated(bs, cur_sector, MAX_IS_ALLOCATED_SEARCH, |
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&nr_sectors)) { |
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cur_sector += nr_sectors; |
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} |
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} |
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if (cur_sector >= total_sectors) {
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bmds->cur_sector = bmds->completed_sectors = total_sectors; |
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return 1; |
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} |
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bmds->completed_sectors = cur_sector; |
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cur_sector &= ~((int64_t)BDRV_SECTORS_PER_DIRTY_CHUNK - 1);
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/* we are going to transfer a full block even if it is not allocated */
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nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK; |
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if (total_sectors - cur_sector < BDRV_SECTORS_PER_DIRTY_CHUNK) {
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nr_sectors = total_sectors - cur_sector; |
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} |
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blk = qemu_malloc(sizeof(BlkMigBlock));
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blk->buf = qemu_malloc(BLOCK_SIZE); |
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blk->bmds = bmds; |
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blk->sector = cur_sector; |
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blk->iov.iov_base = blk->buf; |
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blk->iov.iov_len = nr_sectors * BDRV_SECTOR_SIZE; |
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qemu_iovec_init_external(&blk->qiov, &blk->iov, 1);
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blk->aiocb = bdrv_aio_readv(bs, cur_sector, &blk->qiov, |
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nr_sectors, blk_mig_read_cb, blk); |
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if (!blk->aiocb) {
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goto error;
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} |
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block_mig_state.submitted++; |
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bdrv_reset_dirty(bs, cur_sector, nr_sectors); |
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bmds->cur_sector = cur_sector + nr_sectors; |
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return (bmds->cur_sector >= total_sectors);
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error:
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monitor_printf(mon, "Error reading sector %" PRId64 "\n", cur_sector); |
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qemu_file_set_error(f); |
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qemu_free(blk->buf); |
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qemu_free(blk); |
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return 0; |
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} |
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static void set_dirty_tracking(int enable) |
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{ |
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BlkMigDevState *bmds; |
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QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { |
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bdrv_set_dirty_tracking(bmds->bs, enable); |
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} |
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} |
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static void init_blk_migration(Monitor *mon, QEMUFile *f) |
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{ |
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BlkMigDevState *bmds; |
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BlockDriverState *bs; |
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int64_t sectors; |
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block_mig_state.submitted = 0;
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block_mig_state.read_done = 0;
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block_mig_state.transferred = 0;
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block_mig_state.total_sector_sum = 0;
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block_mig_state.prev_progress = -1;
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block_mig_state.bulk_completed = 0;
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for (bs = bdrv_first; bs != NULL; bs = bs->next) { |
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if (bs->type == BDRV_TYPE_HD) {
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sectors = bdrv_getlength(bs) >> BDRV_SECTOR_BITS; |
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if (sectors == 0) { |
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continue;
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} |
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bmds = qemu_mallocz(sizeof(BlkMigDevState));
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bmds->bs = bs; |
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bmds->bulk_completed = 0;
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bmds->total_sectors = sectors; |
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bmds->completed_sectors = 0;
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bmds->shared_base = block_mig_state.shared_base; |
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block_mig_state.total_sector_sum += sectors; |
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if (bmds->shared_base) {
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monitor_printf(mon, "Start migration for %s with shared base "
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"image\n",
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bs->device_name); |
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} else {
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monitor_printf(mon, "Start full migration for %s\n",
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bs->device_name); |
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} |
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QSIMPLEQ_INSERT_TAIL(&block_mig_state.bmds_list, bmds, entry); |
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} |
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} |
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} |
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static int blk_mig_save_bulked_block(Monitor *mon, QEMUFile *f) |
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{ |
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int64_t completed_sector_sum = 0;
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BlkMigDevState *bmds; |
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int progress;
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int ret = 0; |
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QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { |
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if (bmds->bulk_completed == 0) { |
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if (mig_save_device_bulk(mon, f, bmds) == 1) { |
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/* completed bulk section for this device */
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bmds->bulk_completed = 1;
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} |
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completed_sector_sum += bmds->completed_sectors; |
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ret = 1;
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break;
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} else {
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completed_sector_sum += bmds->completed_sectors; |
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} |
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} |
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progress = completed_sector_sum * 100 / block_mig_state.total_sector_sum;
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if (progress != block_mig_state.prev_progress) {
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block_mig_state.prev_progress = progress; |
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qemu_put_be64(f, (progress << BDRV_SECTOR_BITS) |
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| BLK_MIG_FLAG_PROGRESS); |
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monitor_printf(mon, "Completed %d %%\r", progress);
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monitor_flush(mon); |
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} |
283 |
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return ret;
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} |
286 |
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static void blk_mig_reset_dirty_cursor(void) |
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{ |
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BlkMigDevState *bmds; |
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|
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QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { |
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bmds->cur_dirty = 0;
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} |
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} |
295 |
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static int mig_save_device_dirty(Monitor *mon, QEMUFile *f, |
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BlkMigDevState *bmds, int is_async)
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{ |
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BlkMigBlock *blk; |
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int64_t total_sectors = bmds->total_sectors; |
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int64_t sector; |
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int nr_sectors;
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|
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for (sector = bmds->cur_dirty; sector < bmds->total_sectors;) {
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if (bdrv_get_dirty(bmds->bs, sector)) {
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|
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if (total_sectors - sector < BDRV_SECTORS_PER_DIRTY_CHUNK) {
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nr_sectors = total_sectors - sector; |
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} else {
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nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK; |
311 |
} |
312 |
blk = qemu_malloc(sizeof(BlkMigBlock));
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blk->buf = qemu_malloc(BLOCK_SIZE); |
314 |
blk->bmds = bmds; |
315 |
blk->sector = sector; |
316 |
|
317 |
if(is_async) {
|
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blk->iov.iov_base = blk->buf; |
319 |
blk->iov.iov_len = nr_sectors * BDRV_SECTOR_SIZE; |
320 |
qemu_iovec_init_external(&blk->qiov, &blk->iov, 1);
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|
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blk->aiocb = bdrv_aio_readv(bmds->bs, sector, &blk->qiov, |
323 |
nr_sectors, blk_mig_read_cb, blk); |
324 |
if (!blk->aiocb) {
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goto error;
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} |
327 |
block_mig_state.submitted++; |
328 |
} else {
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329 |
if (bdrv_read(bmds->bs, sector, blk->buf,
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nr_sectors) < 0) {
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goto error;
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332 |
} |
333 |
blk_send(f, blk); |
334 |
|
335 |
qemu_free(blk->buf); |
336 |
qemu_free(blk); |
337 |
} |
338 |
|
339 |
bdrv_reset_dirty(bmds->bs, sector, nr_sectors); |
340 |
break;
|
341 |
} |
342 |
sector += BDRV_SECTORS_PER_DIRTY_CHUNK; |
343 |
bmds->cur_dirty = sector; |
344 |
} |
345 |
|
346 |
return (bmds->cur_dirty >= bmds->total_sectors);
|
347 |
|
348 |
error:
|
349 |
monitor_printf(mon, "Error reading sector %" PRId64 "\n", sector); |
350 |
qemu_file_set_error(f); |
351 |
qemu_free(blk->buf); |
352 |
qemu_free(blk); |
353 |
return 0; |
354 |
} |
355 |
|
356 |
static int blk_mig_save_dirty_block(Monitor *mon, QEMUFile *f, int is_async) |
357 |
{ |
358 |
BlkMigDevState *bmds; |
359 |
int ret = 0; |
360 |
|
361 |
QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { |
362 |
if(mig_save_device_dirty(mon, f, bmds, is_async) == 0) { |
363 |
ret = 1;
|
364 |
break;
|
365 |
} |
366 |
} |
367 |
|
368 |
return ret;
|
369 |
} |
370 |
|
371 |
static void flush_blks(QEMUFile* f) |
372 |
{ |
373 |
BlkMigBlock *blk; |
374 |
|
375 |
DPRINTF("%s Enter submitted %d read_done %d transferred %d\n",
|
376 |
__FUNCTION__, block_mig_state.submitted, block_mig_state.read_done, |
377 |
block_mig_state.transferred); |
378 |
|
379 |
while ((blk = QSIMPLEQ_FIRST(&block_mig_state.blk_list)) != NULL) { |
380 |
if (qemu_file_rate_limit(f)) {
|
381 |
break;
|
382 |
} |
383 |
if (blk->ret < 0) { |
384 |
qemu_file_set_error(f); |
385 |
break;
|
386 |
} |
387 |
blk_send(f, blk); |
388 |
|
389 |
QSIMPLEQ_REMOVE_HEAD(&block_mig_state.blk_list, entry); |
390 |
qemu_free(blk->buf); |
391 |
qemu_free(blk); |
392 |
|
393 |
block_mig_state.read_done--; |
394 |
block_mig_state.transferred++; |
395 |
assert(block_mig_state.read_done >= 0);
|
396 |
} |
397 |
|
398 |
DPRINTF("%s Exit submitted %d read_done %d transferred %d\n", __FUNCTION__,
|
399 |
block_mig_state.submitted, block_mig_state.read_done, |
400 |
block_mig_state.transferred); |
401 |
} |
402 |
|
403 |
static int is_stage2_completed(void) |
404 |
{ |
405 |
return (block_mig_state.submitted == 0 && block_mig_state.bulk_completed); |
406 |
} |
407 |
|
408 |
static void blk_mig_cleanup(Monitor *mon) |
409 |
{ |
410 |
BlkMigDevState *bmds; |
411 |
BlkMigBlock *blk; |
412 |
|
413 |
while ((bmds = QSIMPLEQ_FIRST(&block_mig_state.bmds_list)) != NULL) { |
414 |
QSIMPLEQ_REMOVE_HEAD(&block_mig_state.bmds_list, entry); |
415 |
qemu_free(bmds); |
416 |
} |
417 |
|
418 |
while ((blk = QSIMPLEQ_FIRST(&block_mig_state.blk_list)) != NULL) { |
419 |
QSIMPLEQ_REMOVE_HEAD(&block_mig_state.blk_list, entry); |
420 |
qemu_free(blk->buf); |
421 |
qemu_free(blk); |
422 |
} |
423 |
|
424 |
set_dirty_tracking(0);
|
425 |
|
426 |
monitor_printf(mon, "\n");
|
427 |
} |
428 |
|
429 |
static int block_save_live(Monitor *mon, QEMUFile *f, int stage, void *opaque) |
430 |
{ |
431 |
DPRINTF("Enter save live stage %d submitted %d transferred %d\n",
|
432 |
stage, block_mig_state.submitted, block_mig_state.transferred); |
433 |
|
434 |
if (stage < 0) { |
435 |
blk_mig_cleanup(mon); |
436 |
return 0; |
437 |
} |
438 |
|
439 |
if (block_mig_state.blk_enable != 1) { |
440 |
/* no need to migrate storage */
|
441 |
qemu_put_be64(f, BLK_MIG_FLAG_EOS); |
442 |
return 1; |
443 |
} |
444 |
|
445 |
if (stage == 1) { |
446 |
init_blk_migration(mon, f); |
447 |
|
448 |
/* start track dirty blocks */
|
449 |
set_dirty_tracking(1);
|
450 |
} |
451 |
|
452 |
flush_blks(f); |
453 |
|
454 |
if (qemu_file_has_error(f)) {
|
455 |
blk_mig_cleanup(mon); |
456 |
return 0; |
457 |
} |
458 |
|
459 |
blk_mig_reset_dirty_cursor(); |
460 |
|
461 |
if(stage == 2) { |
462 |
/* control the rate of transfer */
|
463 |
while ((block_mig_state.submitted +
|
464 |
block_mig_state.read_done) * BLOCK_SIZE < |
465 |
qemu_file_get_rate_limit(f)) { |
466 |
if (block_mig_state.bulk_completed == 0) { |
467 |
/* first finish the bulk phase */
|
468 |
if (blk_mig_save_bulked_block(mon, f) == 0) { |
469 |
/* finish saving bulk on all devices */
|
470 |
block_mig_state.bulk_completed = 1;
|
471 |
} |
472 |
} else {
|
473 |
if (blk_mig_save_dirty_block(mon, f, 1) == 0) { |
474 |
/* no more dirty blocks */
|
475 |
break;
|
476 |
} |
477 |
} |
478 |
} |
479 |
|
480 |
flush_blks(f); |
481 |
|
482 |
if (qemu_file_has_error(f)) {
|
483 |
blk_mig_cleanup(mon); |
484 |
return 0; |
485 |
} |
486 |
} |
487 |
|
488 |
if (stage == 3) { |
489 |
/* we know for sure that save bulk is completed */
|
490 |
|
491 |
while(blk_mig_save_dirty_block(mon, f, 0) != 0); |
492 |
blk_mig_cleanup(mon); |
493 |
|
494 |
/* report completion */
|
495 |
qemu_put_be64(f, (100 << BDRV_SECTOR_BITS) | BLK_MIG_FLAG_PROGRESS);
|
496 |
|
497 |
if (qemu_file_has_error(f)) {
|
498 |
return 0; |
499 |
} |
500 |
|
501 |
monitor_printf(mon, "Block migration completed\n");
|
502 |
} |
503 |
|
504 |
qemu_put_be64(f, BLK_MIG_FLAG_EOS); |
505 |
|
506 |
return ((stage == 2) && is_stage2_completed()); |
507 |
} |
508 |
|
509 |
static int block_load(QEMUFile *f, void *opaque, int version_id) |
510 |
{ |
511 |
static int banner_printed; |
512 |
int len, flags;
|
513 |
char device_name[256]; |
514 |
int64_t addr; |
515 |
BlockDriverState *bs; |
516 |
uint8_t *buf; |
517 |
|
518 |
do {
|
519 |
addr = qemu_get_be64(f); |
520 |
|
521 |
flags = addr & ~BDRV_SECTOR_MASK; |
522 |
addr >>= BDRV_SECTOR_BITS; |
523 |
|
524 |
if (flags & BLK_MIG_FLAG_DEVICE_BLOCK) {
|
525 |
/* get device name */
|
526 |
len = qemu_get_byte(f); |
527 |
qemu_get_buffer(f, (uint8_t *)device_name, len); |
528 |
device_name[len] = '\0';
|
529 |
|
530 |
bs = bdrv_find(device_name); |
531 |
if (!bs) {
|
532 |
fprintf(stderr, "Error unknown block device %s\n",
|
533 |
device_name); |
534 |
return -EINVAL;
|
535 |
} |
536 |
|
537 |
buf = qemu_malloc(BLOCK_SIZE); |
538 |
|
539 |
qemu_get_buffer(f, buf, BLOCK_SIZE); |
540 |
bdrv_write(bs, addr, buf, BDRV_SECTORS_PER_DIRTY_CHUNK); |
541 |
|
542 |
qemu_free(buf); |
543 |
} else if (flags & BLK_MIG_FLAG_PROGRESS) { |
544 |
if (!banner_printed) {
|
545 |
printf("Receiving block device images\n");
|
546 |
banner_printed = 1;
|
547 |
} |
548 |
printf("Completed %d %%%c", (int)addr, |
549 |
(addr == 100) ? '\n' : '\r'); |
550 |
fflush(stdout); |
551 |
} else if (!(flags & BLK_MIG_FLAG_EOS)) { |
552 |
fprintf(stderr, "Unknown flags\n");
|
553 |
return -EINVAL;
|
554 |
} |
555 |
if (qemu_file_has_error(f)) {
|
556 |
return -EIO;
|
557 |
} |
558 |
} while (!(flags & BLK_MIG_FLAG_EOS));
|
559 |
|
560 |
return 0; |
561 |
} |
562 |
|
563 |
static void block_set_params(int blk_enable, int shared_base, void *opaque) |
564 |
{ |
565 |
block_mig_state.blk_enable = blk_enable; |
566 |
block_mig_state.shared_base = shared_base; |
567 |
|
568 |
/* shared base means that blk_enable = 1 */
|
569 |
block_mig_state.blk_enable |= shared_base; |
570 |
} |
571 |
|
572 |
void blk_mig_init(void) |
573 |
{ |
574 |
QSIMPLEQ_INIT(&block_mig_state.bmds_list); |
575 |
QSIMPLEQ_INIT(&block_mig_state.blk_list); |
576 |
|
577 |
register_savevm_live("block", 0, 1, block_set_params, block_save_live, |
578 |
NULL, block_load, &block_mig_state);
|
579 |
} |