| /* |
| * QEMU live block migration |
| * |
| * Copyright IBM, Corp. 2009 |
| * |
| * Authors: |
| * Liran Schour <lirans@il.ibm.com> |
| * |
| * This work is licensed under the terms of the GNU GPL, version 2. See |
| * the COPYING file in the top-level directory. |
| * |
| * Contributions after 2012-01-13 are licensed under the terms of the |
| * GNU GPL, version 2 or (at your option) any later version. |
| */ |
| |
| #include "qemu/osdep.h" |
| #include "qapi/error.h" |
| #include "qemu/error-report.h" |
| #include "qemu/main-loop.h" |
| #include "qemu/cutils.h" |
| #include "qemu/queue.h" |
| #include "block.h" |
| #include "migration/misc.h" |
| #include "migration.h" |
| #include "migration/register.h" |
| #include "qemu-file.h" |
| #include "migration/vmstate.h" |
| #include "sysemu/block-backend.h" |
| #include "trace.h" |
| |
| #define BLK_MIG_BLOCK_SIZE (1ULL << 20) |
| #define BDRV_SECTORS_PER_DIRTY_CHUNK (BLK_MIG_BLOCK_SIZE >> BDRV_SECTOR_BITS) |
| |
| #define BLK_MIG_FLAG_DEVICE_BLOCK 0x01 |
| #define BLK_MIG_FLAG_EOS 0x02 |
| #define BLK_MIG_FLAG_PROGRESS 0x04 |
| #define BLK_MIG_FLAG_ZERO_BLOCK 0x08 |
| |
| #define MAX_IS_ALLOCATED_SEARCH (65536 * BDRV_SECTOR_SIZE) |
| |
| #define MAX_IO_BUFFERS 512 |
| #define MAX_PARALLEL_IO 16 |
| |
| /* #define DEBUG_BLK_MIGRATION */ |
| |
| #ifdef DEBUG_BLK_MIGRATION |
| #define DPRINTF(fmt, ...) \ |
| do { printf("blk_migration: " fmt, ## __VA_ARGS__); } while (0) |
| #else |
| #define DPRINTF(fmt, ...) \ |
| do { } while (0) |
| #endif |
| |
| typedef struct BlkMigDevState { |
| /* Written during setup phase. Can be read without a lock. */ |
| BlockBackend *blk; |
| char *blk_name; |
| int shared_base; |
| int64_t total_sectors; |
| QSIMPLEQ_ENTRY(BlkMigDevState) entry; |
| Error *blocker; |
| |
| /* Only used by migration thread. Does not need a lock. */ |
| int bulk_completed; |
| int64_t cur_sector; |
| int64_t cur_dirty; |
| |
| /* Data in the aio_bitmap is protected by block migration lock. |
| * Allocation and free happen during setup and cleanup respectively. |
| */ |
| unsigned long *aio_bitmap; |
| |
| /* Protected by block migration lock. */ |
| int64_t completed_sectors; |
| |
| /* During migration this is protected by iothread lock / AioContext. |
| * Allocation and free happen during setup and cleanup respectively. |
| */ |
| BdrvDirtyBitmap *dirty_bitmap; |
| } BlkMigDevState; |
| |
| typedef struct BlkMigBlock { |
| /* Only used by migration thread. */ |
| uint8_t *buf; |
| BlkMigDevState *bmds; |
| int64_t sector; |
| int nr_sectors; |
| QEMUIOVector qiov; |
| BlockAIOCB *aiocb; |
| |
| /* Protected by block migration lock. */ |
| int ret; |
| QSIMPLEQ_ENTRY(BlkMigBlock) entry; |
| } BlkMigBlock; |
| |
| typedef struct BlkMigState { |
| QSIMPLEQ_HEAD(, BlkMigDevState) bmds_list; |
| int64_t total_sector_sum; |
| bool zero_blocks; |
| |
| /* Protected by lock. */ |
| QSIMPLEQ_HEAD(, BlkMigBlock) blk_list; |
| int submitted; |
| int read_done; |
| |
| /* Only used by migration thread. Does not need a lock. */ |
| int transferred; |
| int prev_progress; |
| int bulk_completed; |
| |
| /* Lock must be taken _inside_ the iothread lock and any AioContexts. */ |
| QemuMutex lock; |
| } BlkMigState; |
| |
| static BlkMigState block_mig_state; |
| |
| static void blk_mig_lock(void) |
| { |
| qemu_mutex_lock(&block_mig_state.lock); |
| } |
| |
| static void blk_mig_unlock(void) |
| { |
| qemu_mutex_unlock(&block_mig_state.lock); |
| } |
| |
| /* Must run outside of the iothread lock during the bulk phase, |
| * or the VM will stall. |
| */ |
| |
| static void blk_send(QEMUFile *f, BlkMigBlock * blk) |
| { |
| int len; |
| uint64_t flags = BLK_MIG_FLAG_DEVICE_BLOCK; |
| |
| if (block_mig_state.zero_blocks && |
| buffer_is_zero(blk->buf, BLK_MIG_BLOCK_SIZE)) { |
| flags |= BLK_MIG_FLAG_ZERO_BLOCK; |
| } |
| |
| /* sector number and flags */ |
| qemu_put_be64(f, (blk->sector << BDRV_SECTOR_BITS) |
| | flags); |
| |
| /* device name */ |
| len = strlen(blk->bmds->blk_name); |
| qemu_put_byte(f, len); |
| qemu_put_buffer(f, (uint8_t *) blk->bmds->blk_name, len); |
| |
| /* if a block is zero we need to flush here since the network |
| * bandwidth is now a lot higher than the storage device bandwidth. |
| * thus if we queue zero blocks we slow down the migration */ |
| if (flags & BLK_MIG_FLAG_ZERO_BLOCK) { |
| qemu_fflush(f); |
| return; |
| } |
| |
| qemu_put_buffer(f, blk->buf, BLK_MIG_BLOCK_SIZE); |
| } |
| |
| int blk_mig_active(void) |
| { |
| return !QSIMPLEQ_EMPTY(&block_mig_state.bmds_list); |
| } |
| |
| int blk_mig_bulk_active(void) |
| { |
| return blk_mig_active() && !block_mig_state.bulk_completed; |
| } |
| |
| uint64_t blk_mig_bytes_transferred(void) |
| { |
| BlkMigDevState *bmds; |
| uint64_t sum = 0; |
| |
| blk_mig_lock(); |
| QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { |
| sum += bmds->completed_sectors; |
| } |
| blk_mig_unlock(); |
| return sum << BDRV_SECTOR_BITS; |
| } |
| |
| uint64_t blk_mig_bytes_remaining(void) |
| { |
| return blk_mig_bytes_total() - blk_mig_bytes_transferred(); |
| } |
| |
| uint64_t blk_mig_bytes_total(void) |
| { |
| BlkMigDevState *bmds; |
| uint64_t sum = 0; |
| |
| QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { |
| sum += bmds->total_sectors; |
| } |
| return sum << BDRV_SECTOR_BITS; |
| } |
| |
| |
| /* Called with migration lock held. */ |
| |
| static int bmds_aio_inflight(BlkMigDevState *bmds, int64_t sector) |
| { |
| int64_t chunk = sector / (int64_t)BDRV_SECTORS_PER_DIRTY_CHUNK; |
| |
| if (sector < blk_nb_sectors(bmds->blk)) { |
| return !!(bmds->aio_bitmap[chunk / (sizeof(unsigned long) * 8)] & |
| (1UL << (chunk % (sizeof(unsigned long) * 8)))); |
| } else { |
| return 0; |
| } |
| } |
| |
| /* Called with migration lock held. */ |
| |
| static void bmds_set_aio_inflight(BlkMigDevState *bmds, int64_t sector_num, |
| int nb_sectors, int set) |
| { |
| int64_t start, end; |
| unsigned long val, idx, bit; |
| |
| start = sector_num / BDRV_SECTORS_PER_DIRTY_CHUNK; |
| end = (sector_num + nb_sectors - 1) / BDRV_SECTORS_PER_DIRTY_CHUNK; |
| |
| for (; start <= end; start++) { |
| idx = start / (sizeof(unsigned long) * 8); |
| bit = start % (sizeof(unsigned long) * 8); |
| val = bmds->aio_bitmap[idx]; |
| if (set) { |
| val |= 1UL << bit; |
| } else { |
| val &= ~(1UL << bit); |
| } |
| bmds->aio_bitmap[idx] = val; |
| } |
| } |
| |
| static void alloc_aio_bitmap(BlkMigDevState *bmds) |
| { |
| BlockBackend *bb = bmds->blk; |
| int64_t bitmap_size; |
| |
| bitmap_size = blk_nb_sectors(bb) + BDRV_SECTORS_PER_DIRTY_CHUNK * 8 - 1; |
| bitmap_size /= BDRV_SECTORS_PER_DIRTY_CHUNK * 8; |
| |
| bmds->aio_bitmap = g_malloc0(bitmap_size); |
| } |
| |
| /* Never hold migration lock when yielding to the main loop! */ |
| |
| static void blk_mig_read_cb(void *opaque, int ret) |
| { |
| BlkMigBlock *blk = opaque; |
| |
| blk_mig_lock(); |
| blk->ret = ret; |
| |
| QSIMPLEQ_INSERT_TAIL(&block_mig_state.blk_list, blk, entry); |
| bmds_set_aio_inflight(blk->bmds, blk->sector, blk->nr_sectors, 0); |
| |
| block_mig_state.submitted--; |
| block_mig_state.read_done++; |
| assert(block_mig_state.submitted >= 0); |
| blk_mig_unlock(); |
| } |
| |
| /* Called with no lock taken. */ |
| |
| static int mig_save_device_bulk(QEMUFile *f, BlkMigDevState *bmds) |
| { |
| int64_t total_sectors = bmds->total_sectors; |
| int64_t cur_sector = bmds->cur_sector; |
| BlockBackend *bb = bmds->blk; |
| BlkMigBlock *blk; |
| int nr_sectors; |
| int64_t count; |
| |
| if (bmds->shared_base) { |
| qemu_mutex_lock_iothread(); |
| aio_context_acquire(blk_get_aio_context(bb)); |
| /* Skip unallocated sectors; intentionally treats failure or |
| * partial sector as an allocated sector */ |
| while (cur_sector < total_sectors && |
| !bdrv_is_allocated(blk_bs(bb), cur_sector * BDRV_SECTOR_SIZE, |
| MAX_IS_ALLOCATED_SEARCH, &count)) { |
| if (count < BDRV_SECTOR_SIZE) { |
| break; |
| } |
| cur_sector += count >> BDRV_SECTOR_BITS; |
| } |
| aio_context_release(blk_get_aio_context(bb)); |
| qemu_mutex_unlock_iothread(); |
| } |
| |
| if (cur_sector >= total_sectors) { |
| bmds->cur_sector = bmds->completed_sectors = total_sectors; |
| return 1; |
| } |
| |
| bmds->completed_sectors = cur_sector; |
| |
| cur_sector &= ~((int64_t)BDRV_SECTORS_PER_DIRTY_CHUNK - 1); |
| |
| /* we are going to transfer a full block even if it is not allocated */ |
| nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK; |
| |
| if (total_sectors - cur_sector < BDRV_SECTORS_PER_DIRTY_CHUNK) { |
| nr_sectors = total_sectors - cur_sector; |
| } |
| |
| blk = g_new(BlkMigBlock, 1); |
| blk->buf = g_malloc(BLK_MIG_BLOCK_SIZE); |
| blk->bmds = bmds; |
| blk->sector = cur_sector; |
| blk->nr_sectors = nr_sectors; |
| |
| qemu_iovec_init_buf(&blk->qiov, blk->buf, nr_sectors * BDRV_SECTOR_SIZE); |
| |
| blk_mig_lock(); |
| block_mig_state.submitted++; |
| blk_mig_unlock(); |
| |
| /* We do not know if bs is under the main thread (and thus does |
| * not acquire the AioContext when doing AIO) or rather under |
| * dataplane. Thus acquire both the iothread mutex and the |
| * AioContext. |
| * |
| * This is ugly and will disappear when we make bdrv_* thread-safe, |
| * without the need to acquire the AioContext. |
| */ |
| qemu_mutex_lock_iothread(); |
| aio_context_acquire(blk_get_aio_context(bmds->blk)); |
| bdrv_reset_dirty_bitmap(bmds->dirty_bitmap, cur_sector * BDRV_SECTOR_SIZE, |
| nr_sectors * BDRV_SECTOR_SIZE); |
| blk->aiocb = blk_aio_preadv(bb, cur_sector * BDRV_SECTOR_SIZE, &blk->qiov, |
| 0, blk_mig_read_cb, blk); |
| aio_context_release(blk_get_aio_context(bmds->blk)); |
| qemu_mutex_unlock_iothread(); |
| |
| bmds->cur_sector = cur_sector + nr_sectors; |
| return (bmds->cur_sector >= total_sectors); |
| } |
| |
| /* Called with iothread lock taken. */ |
| |
| static int set_dirty_tracking(void) |
| { |
| BlkMigDevState *bmds; |
| int ret; |
| |
| QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { |
| bmds->dirty_bitmap = bdrv_create_dirty_bitmap(blk_bs(bmds->blk), |
| BLK_MIG_BLOCK_SIZE, |
| NULL, NULL); |
| if (!bmds->dirty_bitmap) { |
| ret = -errno; |
| goto fail; |
| } |
| } |
| return 0; |
| |
| fail: |
| QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { |
| if (bmds->dirty_bitmap) { |
| bdrv_release_dirty_bitmap(bmds->dirty_bitmap); |
| } |
| } |
| return ret; |
| } |
| |
| /* Called with iothread lock taken. */ |
| |
| static void unset_dirty_tracking(void) |
| { |
| BlkMigDevState *bmds; |
| |
| QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { |
| if (bmds->dirty_bitmap) { |
| bdrv_release_dirty_bitmap(bmds->dirty_bitmap); |
| } |
| } |
| } |
| |
| static int init_blk_migration(QEMUFile *f) |
| { |
| BlockDriverState *bs; |
| BlkMigDevState *bmds; |
| int64_t sectors; |
| BdrvNextIterator it; |
| int i, num_bs = 0; |
| struct { |
| BlkMigDevState *bmds; |
| BlockDriverState *bs; |
| } *bmds_bs; |
| Error *local_err = NULL; |
| int ret; |
| |
| block_mig_state.submitted = 0; |
| block_mig_state.read_done = 0; |
| block_mig_state.transferred = 0; |
| block_mig_state.total_sector_sum = 0; |
| block_mig_state.prev_progress = -1; |
| block_mig_state.bulk_completed = 0; |
| block_mig_state.zero_blocks = migrate_zero_blocks(); |
| |
| for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { |
| num_bs++; |
| } |
| bmds_bs = g_malloc0(num_bs * sizeof(*bmds_bs)); |
| |
| for (i = 0, bs = bdrv_first(&it); bs; bs = bdrv_next(&it), i++) { |
| if (bdrv_is_read_only(bs)) { |
| continue; |
| } |
| |
| sectors = bdrv_nb_sectors(bs); |
| if (sectors == 0) { |
| continue; |
| } |
| if (sectors < 0) { |
| ret = sectors; |
| bdrv_next_cleanup(&it); |
| goto out; |
| } |
| |
| bmds = g_new0(BlkMigDevState, 1); |
| bmds->blk = blk_new(qemu_get_aio_context(), |
| BLK_PERM_CONSISTENT_READ, BLK_PERM_ALL); |
| bmds->blk_name = g_strdup(bdrv_get_device_name(bs)); |
| bmds->bulk_completed = 0; |
| bmds->total_sectors = sectors; |
| bmds->completed_sectors = 0; |
| bmds->shared_base = migrate_use_block_incremental(); |
| |
| assert(i < num_bs); |
| bmds_bs[i].bmds = bmds; |
| bmds_bs[i].bs = bs; |
| |
| block_mig_state.total_sector_sum += sectors; |
| |
| if (bmds->shared_base) { |
| trace_migration_block_init_shared(bdrv_get_device_name(bs)); |
| } else { |
| trace_migration_block_init_full(bdrv_get_device_name(bs)); |
| } |
| |
| QSIMPLEQ_INSERT_TAIL(&block_mig_state.bmds_list, bmds, entry); |
| } |
| |
| /* Can only insert new BDSes now because doing so while iterating block |
| * devices may end up in a deadlock (iterating the new BDSes, too). */ |
| for (i = 0; i < num_bs; i++) { |
| BlkMigDevState *bmds = bmds_bs[i].bmds; |
| BlockDriverState *bs = bmds_bs[i].bs; |
| |
| if (bmds) { |
| ret = blk_insert_bs(bmds->blk, bs, &local_err); |
| if (ret < 0) { |
| error_report_err(local_err); |
| goto out; |
| } |
| |
| alloc_aio_bitmap(bmds); |
| error_setg(&bmds->blocker, "block device is in use by migration"); |
| bdrv_op_block_all(bs, bmds->blocker); |
| } |
| } |
| |
| ret = 0; |
| out: |
| g_free(bmds_bs); |
| return ret; |
| } |
| |
| /* Called with no lock taken. */ |
| |
| static int blk_mig_save_bulked_block(QEMUFile *f) |
| { |
| int64_t completed_sector_sum = 0; |
| BlkMigDevState *bmds; |
| int progress; |
| int ret = 0; |
| |
| QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { |
| if (bmds->bulk_completed == 0) { |
| if (mig_save_device_bulk(f, bmds) == 1) { |
| /* completed bulk section for this device */ |
| bmds->bulk_completed = 1; |
| } |
| completed_sector_sum += bmds->completed_sectors; |
| ret = 1; |
| break; |
| } else { |
| completed_sector_sum += bmds->completed_sectors; |
| } |
| } |
| |
| if (block_mig_state.total_sector_sum != 0) { |
| progress = completed_sector_sum * 100 / |
| block_mig_state.total_sector_sum; |
| } else { |
| progress = 100; |
| } |
| if (progress != block_mig_state.prev_progress) { |
| block_mig_state.prev_progress = progress; |
| qemu_put_be64(f, (progress << BDRV_SECTOR_BITS) |
| | BLK_MIG_FLAG_PROGRESS); |
| DPRINTF("Completed %d %%\r", progress); |
| } |
| |
| return ret; |
| } |
| |
| static void blk_mig_reset_dirty_cursor(void) |
| { |
| BlkMigDevState *bmds; |
| |
| QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { |
| bmds->cur_dirty = 0; |
| } |
| } |
| |
| /* Called with iothread lock and AioContext taken. */ |
| |
| static int mig_save_device_dirty(QEMUFile *f, BlkMigDevState *bmds, |
| int is_async) |
| { |
| BlkMigBlock *blk; |
| int64_t total_sectors = bmds->total_sectors; |
| int64_t sector; |
| int nr_sectors; |
| int ret = -EIO; |
| |
| for (sector = bmds->cur_dirty; sector < bmds->total_sectors;) { |
| blk_mig_lock(); |
| if (bmds_aio_inflight(bmds, sector)) { |
| blk_mig_unlock(); |
| blk_drain(bmds->blk); |
| } else { |
| blk_mig_unlock(); |
| } |
| bdrv_dirty_bitmap_lock(bmds->dirty_bitmap); |
| if (bdrv_dirty_bitmap_get_locked(bmds->dirty_bitmap, |
| sector * BDRV_SECTOR_SIZE)) { |
| if (total_sectors - sector < BDRV_SECTORS_PER_DIRTY_CHUNK) { |
| nr_sectors = total_sectors - sector; |
| } else { |
| nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK; |
| } |
| bdrv_reset_dirty_bitmap_locked(bmds->dirty_bitmap, |
| sector * BDRV_SECTOR_SIZE, |
| nr_sectors * BDRV_SECTOR_SIZE); |
| bdrv_dirty_bitmap_unlock(bmds->dirty_bitmap); |
| |
| blk = g_new(BlkMigBlock, 1); |
| blk->buf = g_malloc(BLK_MIG_BLOCK_SIZE); |
| blk->bmds = bmds; |
| blk->sector = sector; |
| blk->nr_sectors = nr_sectors; |
| |
| if (is_async) { |
| qemu_iovec_init_buf(&blk->qiov, blk->buf, |
| nr_sectors * BDRV_SECTOR_SIZE); |
| |
| blk->aiocb = blk_aio_preadv(bmds->blk, |
| sector * BDRV_SECTOR_SIZE, |
| &blk->qiov, 0, blk_mig_read_cb, |
| blk); |
| |
| blk_mig_lock(); |
| block_mig_state.submitted++; |
| bmds_set_aio_inflight(bmds, sector, nr_sectors, 1); |
| blk_mig_unlock(); |
| } else { |
| ret = blk_pread(bmds->blk, sector * BDRV_SECTOR_SIZE, |
| nr_sectors * BDRV_SECTOR_SIZE, blk->buf, 0); |
| if (ret < 0) { |
| goto error; |
| } |
| blk_send(f, blk); |
| |
| g_free(blk->buf); |
| g_free(blk); |
| } |
| |
| sector += nr_sectors; |
| bmds->cur_dirty = sector; |
| break; |
| } |
| |
| bdrv_dirty_bitmap_unlock(bmds->dirty_bitmap); |
| sector += BDRV_SECTORS_PER_DIRTY_CHUNK; |
| bmds->cur_dirty = sector; |
| } |
| |
| return (bmds->cur_dirty >= bmds->total_sectors); |
| |
| error: |
| trace_migration_block_save_device_dirty(sector); |
| g_free(blk->buf); |
| g_free(blk); |
| return ret; |
| } |
| |
| /* Called with iothread lock taken. |
| * |
| * return value: |
| * 0: too much data for max_downtime |
| * 1: few enough data for max_downtime |
| */ |
| static int blk_mig_save_dirty_block(QEMUFile *f, int is_async) |
| { |
| BlkMigDevState *bmds; |
| int ret = 1; |
| |
| QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { |
| aio_context_acquire(blk_get_aio_context(bmds->blk)); |
| ret = mig_save_device_dirty(f, bmds, is_async); |
| aio_context_release(blk_get_aio_context(bmds->blk)); |
| if (ret <= 0) { |
| break; |
| } |
| } |
| |
| return ret; |
| } |
| |
| /* Called with no locks taken. */ |
| |
| static int flush_blks(QEMUFile *f) |
| { |
| BlkMigBlock *blk; |
| int ret = 0; |
| |
| trace_migration_block_flush_blks("Enter", block_mig_state.submitted, |
| block_mig_state.read_done, |
| block_mig_state.transferred); |
| |
| blk_mig_lock(); |
| while ((blk = QSIMPLEQ_FIRST(&block_mig_state.blk_list)) != NULL) { |
| if (qemu_file_rate_limit(f)) { |
| break; |
| } |
| if (blk->ret < 0) { |
| ret = blk->ret; |
| break; |
| } |
| |
| QSIMPLEQ_REMOVE_HEAD(&block_mig_state.blk_list, entry); |
| blk_mig_unlock(); |
| blk_send(f, blk); |
| blk_mig_lock(); |
| |
| g_free(blk->buf); |
| g_free(blk); |
| |
| block_mig_state.read_done--; |
| block_mig_state.transferred++; |
| assert(block_mig_state.read_done >= 0); |
| } |
| blk_mig_unlock(); |
| |
| trace_migration_block_flush_blks("Exit", block_mig_state.submitted, |
| block_mig_state.read_done, |
| block_mig_state.transferred); |
| return ret; |
| } |
| |
| /* Called with iothread lock taken. */ |
| |
| static int64_t get_remaining_dirty(void) |
| { |
| BlkMigDevState *bmds; |
| int64_t dirty = 0; |
| |
| QSIMPLEQ_FOREACH(bmds, &block_mig_state.bmds_list, entry) { |
| aio_context_acquire(blk_get_aio_context(bmds->blk)); |
| dirty += bdrv_get_dirty_count(bmds->dirty_bitmap); |
| aio_context_release(blk_get_aio_context(bmds->blk)); |
| } |
| |
| return dirty; |
| } |
| |
| |
| |
| /* Called with iothread lock taken. */ |
| static void block_migration_cleanup_bmds(void) |
| { |
| BlkMigDevState *bmds; |
| BlockDriverState *bs; |
| AioContext *ctx; |
| |
| unset_dirty_tracking(); |
| |
| while ((bmds = QSIMPLEQ_FIRST(&block_mig_state.bmds_list)) != NULL) { |
| QSIMPLEQ_REMOVE_HEAD(&block_mig_state.bmds_list, entry); |
| |
| bs = blk_bs(bmds->blk); |
| if (bs) { |
| bdrv_op_unblock_all(bs, bmds->blocker); |
| } |
| error_free(bmds->blocker); |
| |
| /* Save ctx, because bmds->blk can disappear during blk_unref. */ |
| ctx = blk_get_aio_context(bmds->blk); |
| aio_context_acquire(ctx); |
| blk_unref(bmds->blk); |
| aio_context_release(ctx); |
| |
| g_free(bmds->blk_name); |
| g_free(bmds->aio_bitmap); |
| g_free(bmds); |
| } |
| } |
| |
| /* Called with iothread lock taken. */ |
| static void block_migration_cleanup(void *opaque) |
| { |
| BlkMigBlock *blk; |
| |
| bdrv_drain_all(); |
| |
| block_migration_cleanup_bmds(); |
| |
| blk_mig_lock(); |
| while ((blk = QSIMPLEQ_FIRST(&block_mig_state.blk_list)) != NULL) { |
| QSIMPLEQ_REMOVE_HEAD(&block_mig_state.blk_list, entry); |
| g_free(blk->buf); |
| g_free(blk); |
| } |
| blk_mig_unlock(); |
| } |
| |
| static int block_save_setup(QEMUFile *f, void *opaque) |
| { |
| int ret; |
| |
| trace_migration_block_save("setup", block_mig_state.submitted, |
| block_mig_state.transferred); |
| |
| qemu_mutex_lock_iothread(); |
| ret = init_blk_migration(f); |
| if (ret < 0) { |
| qemu_mutex_unlock_iothread(); |
| return ret; |
| } |
| |
| /* start track dirty blocks */ |
| ret = set_dirty_tracking(); |
| |
| qemu_mutex_unlock_iothread(); |
| |
| if (ret) { |
| return ret; |
| } |
| |
| ret = flush_blks(f); |
| blk_mig_reset_dirty_cursor(); |
| qemu_put_be64(f, BLK_MIG_FLAG_EOS); |
| |
| return ret; |
| } |
| |
| static int block_save_iterate(QEMUFile *f, void *opaque) |
| { |
| int ret; |
| int64_t last_bytes = qemu_file_total_transferred(f); |
| int64_t delta_bytes; |
| |
| trace_migration_block_save("iterate", block_mig_state.submitted, |
| block_mig_state.transferred); |
| |
| ret = flush_blks(f); |
| if (ret) { |
| return ret; |
| } |
| |
| blk_mig_reset_dirty_cursor(); |
| |
| /* control the rate of transfer */ |
| blk_mig_lock(); |
| while (block_mig_state.read_done * BLK_MIG_BLOCK_SIZE < |
| qemu_file_get_rate_limit(f) && |
| block_mig_state.submitted < MAX_PARALLEL_IO && |
| (block_mig_state.submitted + block_mig_state.read_done) < |
| MAX_IO_BUFFERS) { |
| blk_mig_unlock(); |
| if (block_mig_state.bulk_completed == 0) { |
| /* first finish the bulk phase */ |
| if (blk_mig_save_bulked_block(f) == 0) { |
| /* finished saving bulk on all devices */ |
| block_mig_state.bulk_completed = 1; |
| } |
| ret = 0; |
| } else { |
| /* Always called with iothread lock taken for |
| * simplicity, block_save_complete also calls it. |
| */ |
| qemu_mutex_lock_iothread(); |
| ret = blk_mig_save_dirty_block(f, 1); |
| qemu_mutex_unlock_iothread(); |
| } |
| if (ret < 0) { |
| return ret; |
| } |
| blk_mig_lock(); |
| if (ret != 0) { |
| /* no more dirty blocks */ |
| break; |
| } |
| } |
| blk_mig_unlock(); |
| |
| ret = flush_blks(f); |
| if (ret) { |
| return ret; |
| } |
| |
| qemu_put_be64(f, BLK_MIG_FLAG_EOS); |
| delta_bytes = qemu_file_total_transferred(f) - last_bytes; |
| if (delta_bytes > 0) { |
| return 1; |
| } else if (delta_bytes < 0) { |
| return -1; |
| } else { |
| return 0; |
| } |
| } |
| |
| /* Called with iothread lock taken. */ |
| |
| static int block_save_complete(QEMUFile *f, void *opaque) |
| { |
| int ret; |
| |
| trace_migration_block_save("complete", block_mig_state.submitted, |
| block_mig_state.transferred); |
| |
| ret = flush_blks(f); |
| if (ret) { |
| return ret; |
| } |
| |
| blk_mig_reset_dirty_cursor(); |
| |
| /* we know for sure that save bulk is completed and |
| all async read completed */ |
| blk_mig_lock(); |
| assert(block_mig_state.submitted == 0); |
| blk_mig_unlock(); |
| |
| do { |
| ret = blk_mig_save_dirty_block(f, 0); |
| if (ret < 0) { |
| return ret; |
| } |
| } while (ret == 0); |
| |
| /* report completion */ |
| qemu_put_be64(f, (100 << BDRV_SECTOR_BITS) | BLK_MIG_FLAG_PROGRESS); |
| |
| trace_migration_block_save_complete(); |
| |
| qemu_put_be64(f, BLK_MIG_FLAG_EOS); |
| |
| /* Make sure that our BlockBackends are gone, so that the block driver |
| * nodes can be inactivated. */ |
| block_migration_cleanup_bmds(); |
| |
| return 0; |
| } |
| |
| static void block_save_pending(QEMUFile *f, void *opaque, uint64_t max_size, |
| uint64_t *res_precopy_only, |
| uint64_t *res_compatible, |
| uint64_t *res_postcopy_only) |
| { |
| /* Estimate pending number of bytes to send */ |
| uint64_t pending; |
| |
| qemu_mutex_lock_iothread(); |
| pending = get_remaining_dirty(); |
| qemu_mutex_unlock_iothread(); |
| |
| blk_mig_lock(); |
| pending += block_mig_state.submitted * BLK_MIG_BLOCK_SIZE + |
| block_mig_state.read_done * BLK_MIG_BLOCK_SIZE; |
| blk_mig_unlock(); |
| |
| /* Report at least one block pending during bulk phase */ |
| if (!pending && !block_mig_state.bulk_completed) { |
| pending = BLK_MIG_BLOCK_SIZE; |
| } |
| |
| trace_migration_block_save_pending(pending); |
| /* We don't do postcopy */ |
| *res_precopy_only += pending; |
| } |
| |
| static int block_load(QEMUFile *f, void *opaque, int version_id) |
| { |
| static int banner_printed; |
| int len, flags; |
| char device_name[256]; |
| int64_t addr; |
| BlockBackend *blk, *blk_prev = NULL; |
| Error *local_err = NULL; |
| uint8_t *buf; |
| int64_t total_sectors = 0; |
| int nr_sectors; |
| int ret; |
| BlockDriverInfo bdi; |
| int cluster_size = BLK_MIG_BLOCK_SIZE; |
| |
| do { |
| addr = qemu_get_be64(f); |
| |
| flags = addr & (BDRV_SECTOR_SIZE - 1); |
| addr >>= BDRV_SECTOR_BITS; |
| |
| if (flags & BLK_MIG_FLAG_DEVICE_BLOCK) { |
| /* get device name */ |
| len = qemu_get_byte(f); |
| qemu_get_buffer(f, (uint8_t *)device_name, len); |
| device_name[len] = '\0'; |
| |
| blk = blk_by_name(device_name); |
| if (!blk) { |
| fprintf(stderr, "Error unknown block device %s\n", |
| device_name); |
| return -EINVAL; |
| } |
| |
| if (blk != blk_prev) { |
| blk_prev = blk; |
| total_sectors = blk_nb_sectors(blk); |
| if (total_sectors <= 0) { |
| error_report("Error getting length of block device %s", |
| device_name); |
| return -EINVAL; |
| } |
| |
| blk_activate(blk, &local_err); |
| if (local_err) { |
| error_report_err(local_err); |
| return -EINVAL; |
| } |
| |
| ret = bdrv_get_info(blk_bs(blk), &bdi); |
| if (ret == 0 && bdi.cluster_size > 0 && |
| bdi.cluster_size <= BLK_MIG_BLOCK_SIZE && |
| BLK_MIG_BLOCK_SIZE % bdi.cluster_size == 0) { |
| cluster_size = bdi.cluster_size; |
| } else { |
| cluster_size = BLK_MIG_BLOCK_SIZE; |
| } |
| } |
| |
| if (total_sectors - addr < BDRV_SECTORS_PER_DIRTY_CHUNK) { |
| nr_sectors = total_sectors - addr; |
| } else { |
| nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK; |
| } |
| |
| if (flags & BLK_MIG_FLAG_ZERO_BLOCK) { |
| ret = blk_pwrite_zeroes(blk, addr * BDRV_SECTOR_SIZE, |
| nr_sectors * BDRV_SECTOR_SIZE, |
| BDRV_REQ_MAY_UNMAP); |
| } else { |
| int i; |
| int64_t cur_addr; |
| uint8_t *cur_buf; |
| |
| buf = g_malloc(BLK_MIG_BLOCK_SIZE); |
| qemu_get_buffer(f, buf, BLK_MIG_BLOCK_SIZE); |
| for (i = 0; i < BLK_MIG_BLOCK_SIZE / cluster_size; i++) { |
| cur_addr = addr * BDRV_SECTOR_SIZE + i * cluster_size; |
| cur_buf = buf + i * cluster_size; |
| |
| if ((!block_mig_state.zero_blocks || |
| cluster_size < BLK_MIG_BLOCK_SIZE) && |
| buffer_is_zero(cur_buf, cluster_size)) { |
| ret = blk_pwrite_zeroes(blk, cur_addr, |
| cluster_size, |
| BDRV_REQ_MAY_UNMAP); |
| } else { |
| ret = blk_pwrite(blk, cur_addr, cluster_size, cur_buf, |
| 0); |
| } |
| if (ret < 0) { |
| break; |
| } |
| } |
| g_free(buf); |
| } |
| |
| if (ret < 0) { |
| return ret; |
| } |
| } else if (flags & BLK_MIG_FLAG_PROGRESS) { |
| if (!banner_printed) { |
| printf("Receiving block device images\n"); |
| banner_printed = 1; |
| } |
| printf("Completed %d %%%c", (int)addr, |
| (addr == 100) ? '\n' : '\r'); |
| fflush(stdout); |
| } else if (!(flags & BLK_MIG_FLAG_EOS)) { |
| fprintf(stderr, "Unknown block migration flags: 0x%x\n", flags); |
| return -EINVAL; |
| } |
| ret = qemu_file_get_error(f); |
| if (ret != 0) { |
| return ret; |
| } |
| } while (!(flags & BLK_MIG_FLAG_EOS)); |
| |
| return 0; |
| } |
| |
| static bool block_is_active(void *opaque) |
| { |
| return migrate_use_block(); |
| } |
| |
| static SaveVMHandlers savevm_block_handlers = { |
| .save_setup = block_save_setup, |
| .save_live_iterate = block_save_iterate, |
| .save_live_complete_precopy = block_save_complete, |
| .save_live_pending = block_save_pending, |
| .load_state = block_load, |
| .save_cleanup = block_migration_cleanup, |
| .is_active = block_is_active, |
| }; |
| |
| void blk_mig_init(void) |
| { |
| QSIMPLEQ_INIT(&block_mig_state.bmds_list); |
| QSIMPLEQ_INIT(&block_mig_state.blk_list); |
| qemu_mutex_init(&block_mig_state.lock); |
| |
| register_savevm_live("block", 0, 1, &savevm_block_handlers, |
| &block_mig_state); |
| } |
