diff options
Diffstat (limited to 'block/backup.c')
| -rw-r--r-- | block/backup.c | 507 |
1 files changed, 507 insertions, 0 deletions
diff --git a/block/backup.c b/block/backup.c new file mode 100644 index 000000000..21d598377 --- /dev/null +++ b/block/backup.c @@ -0,0 +1,507 @@ +/* + * QEMU backup + * + * Copyright (C) 2013 Proxmox Server Solutions + * Copyright (c) 2019 Virtuozzo International GmbH. + * + * Authors: + * Dietmar Maurer (dietmar@proxmox.com) + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + * + */ + +#include "qemu/osdep.h" + +#include "trace.h" +#include "block/block.h" +#include "block/block_int.h" +#include "block/blockjob_int.h" +#include "block/block_backup.h" +#include "block/block-copy.h" +#include "qapi/error.h" +#include "qapi/qmp/qerror.h" +#include "qemu/cutils.h" +#include "sysemu/block-backend.h" +#include "qemu/bitmap.h" +#include "qemu/error-report.h" + +#include "block/copy-before-write.h" + +typedef struct BackupBlockJob { + BlockJob common; + BlockDriverState *cbw; + BlockDriverState *source_bs; + BlockDriverState *target_bs; + + BdrvDirtyBitmap *sync_bitmap; + + MirrorSyncMode sync_mode; + BitmapSyncMode bitmap_mode; + BlockdevOnError on_source_error; + BlockdevOnError on_target_error; + uint64_t len; + int64_t cluster_size; + BackupPerf perf; + + BlockCopyState *bcs; + + bool wait; + BlockCopyCallState *bg_bcs_call; +} BackupBlockJob; + +static const BlockJobDriver backup_job_driver; + +static void backup_cleanup_sync_bitmap(BackupBlockJob *job, int ret) +{ + BdrvDirtyBitmap *bm; + bool sync = (((ret == 0) || (job->bitmap_mode == BITMAP_SYNC_MODE_ALWAYS)) \ + && (job->bitmap_mode != BITMAP_SYNC_MODE_NEVER)); + + if (sync) { + /* + * We succeeded, or we always intended to sync the bitmap. + * Delete this bitmap and install the child. + */ + bm = bdrv_dirty_bitmap_abdicate(job->sync_bitmap, NULL); + } else { + /* + * We failed, or we never intended to sync the bitmap anyway. + * Merge the successor back into the parent, keeping all data. + */ + bm = bdrv_reclaim_dirty_bitmap(job->sync_bitmap, NULL); + } + + assert(bm); + + if (ret < 0 && job->bitmap_mode == BITMAP_SYNC_MODE_ALWAYS) { + /* If we failed and synced, merge in the bits we didn't copy: */ + bdrv_dirty_bitmap_merge_internal(bm, block_copy_dirty_bitmap(job->bcs), + NULL, true); + } +} + +static void backup_commit(Job *job) +{ + BackupBlockJob *s = container_of(job, BackupBlockJob, common.job); + if (s->sync_bitmap) { + backup_cleanup_sync_bitmap(s, 0); + } +} + +static void backup_abort(Job *job) +{ + BackupBlockJob *s = container_of(job, BackupBlockJob, common.job); + if (s->sync_bitmap) { + backup_cleanup_sync_bitmap(s, -1); + } +} + +static void backup_clean(Job *job) +{ + BackupBlockJob *s = container_of(job, BackupBlockJob, common.job); + block_job_remove_all_bdrv(&s->common); + bdrv_cbw_drop(s->cbw); +} + +void backup_do_checkpoint(BlockJob *job, Error **errp) +{ + BackupBlockJob *backup_job = container_of(job, BackupBlockJob, common); + + assert(block_job_driver(job) == &backup_job_driver); + + if (backup_job->sync_mode != MIRROR_SYNC_MODE_NONE) { + error_setg(errp, "The backup job only supports block checkpoint in" + " sync=none mode"); + return; + } + + bdrv_set_dirty_bitmap(block_copy_dirty_bitmap(backup_job->bcs), 0, + backup_job->len); +} + +static BlockErrorAction backup_error_action(BackupBlockJob *job, + bool read, int error) +{ + if (read) { + return block_job_error_action(&job->common, job->on_source_error, + true, error); + } else { + return block_job_error_action(&job->common, job->on_target_error, + false, error); + } +} + +static void coroutine_fn backup_block_copy_callback(void *opaque) +{ + BackupBlockJob *s = opaque; + + if (s->wait) { + s->wait = false; + aio_co_wake(s->common.job.co); + } else { + job_enter(&s->common.job); + } +} + +static int coroutine_fn backup_loop(BackupBlockJob *job) +{ + BlockCopyCallState *s = NULL; + int ret = 0; + bool error_is_read; + BlockErrorAction act; + + while (true) { /* retry loop */ + job->bg_bcs_call = s = block_copy_async(job->bcs, 0, + QEMU_ALIGN_UP(job->len, job->cluster_size), + job->perf.max_workers, job->perf.max_chunk, + backup_block_copy_callback, job); + + while (!block_copy_call_finished(s) && + !job_is_cancelled(&job->common.job)) + { + job_yield(&job->common.job); + } + + if (!block_copy_call_finished(s)) { + assert(job_is_cancelled(&job->common.job)); + /* + * Note that we can't use job_yield() here, as it doesn't work for + * cancelled job. + */ + block_copy_call_cancel(s); + job->wait = true; + qemu_coroutine_yield(); + assert(block_copy_call_finished(s)); + ret = 0; + goto out; + } + + if (job_is_cancelled(&job->common.job) || + block_copy_call_succeeded(s)) + { + ret = 0; + goto out; + } + + if (block_copy_call_cancelled(s)) { + /* + * Job is not cancelled but only block-copy call. This is possible + * after job pause. Now the pause is finished, start new block-copy + * iteration. + */ + block_copy_call_free(s); + continue; + } + + /* The only remaining case is failed block-copy call. */ + assert(block_copy_call_failed(s)); + + ret = block_copy_call_status(s, &error_is_read); + act = backup_error_action(job, error_is_read, -ret); + switch (act) { + case BLOCK_ERROR_ACTION_REPORT: + goto out; + case BLOCK_ERROR_ACTION_STOP: + /* + * Go to pause prior to starting new block-copy call on the next + * iteration. + */ + job_pause_point(&job->common.job); + break; + case BLOCK_ERROR_ACTION_IGNORE: + /* Proceed to new block-copy call to retry. */ + break; + default: + abort(); + } + + block_copy_call_free(s); + } + +out: + block_copy_call_free(s); + job->bg_bcs_call = NULL; + return ret; +} + +static void backup_init_bcs_bitmap(BackupBlockJob *job) +{ + bool ret; + uint64_t estimate; + BdrvDirtyBitmap *bcs_bitmap = block_copy_dirty_bitmap(job->bcs); + + if (job->sync_mode == MIRROR_SYNC_MODE_BITMAP) { + bdrv_clear_dirty_bitmap(bcs_bitmap, NULL); + ret = bdrv_dirty_bitmap_merge_internal(bcs_bitmap, job->sync_bitmap, + NULL, true); + assert(ret); + } else if (job->sync_mode == MIRROR_SYNC_MODE_TOP) { + /* + * We can't hog the coroutine to initialize this thoroughly. + * Set a flag and resume work when we are able to yield safely. + */ + block_copy_set_skip_unallocated(job->bcs, true); + } + + estimate = bdrv_get_dirty_count(bcs_bitmap); + job_progress_set_remaining(&job->common.job, estimate); +} + +static int coroutine_fn backup_run(Job *job, Error **errp) +{ + BackupBlockJob *s = container_of(job, BackupBlockJob, common.job); + int ret; + + backup_init_bcs_bitmap(s); + + if (s->sync_mode == MIRROR_SYNC_MODE_TOP) { + int64_t offset = 0; + int64_t count; + + for (offset = 0; offset < s->len; ) { + if (job_is_cancelled(job)) { + return -ECANCELED; + } + + job_pause_point(job); + + if (job_is_cancelled(job)) { + return -ECANCELED; + } + + ret = block_copy_reset_unallocated(s->bcs, offset, &count); + if (ret < 0) { + return ret; + } + + offset += count; + } + block_copy_set_skip_unallocated(s->bcs, false); + } + + if (s->sync_mode == MIRROR_SYNC_MODE_NONE) { + /* + * All bits are set in bcs bitmap to allow any cluster to be copied. + * This does not actually require them to be copied. + */ + while (!job_is_cancelled(job)) { + /* + * Yield until the job is cancelled. We just let our before_write + * notify callback service CoW requests. + */ + job_yield(job); + } + } else { + return backup_loop(s); + } + + return 0; +} + +static void coroutine_fn backup_pause(Job *job) +{ + BackupBlockJob *s = container_of(job, BackupBlockJob, common.job); + + if (s->bg_bcs_call && !block_copy_call_finished(s->bg_bcs_call)) { + block_copy_call_cancel(s->bg_bcs_call); + s->wait = true; + qemu_coroutine_yield(); + } +} + +static void coroutine_fn backup_set_speed(BlockJob *job, int64_t speed) +{ + BackupBlockJob *s = container_of(job, BackupBlockJob, common); + + /* + * block_job_set_speed() is called first from block_job_create(), when we + * don't yet have s->bcs. + */ + if (s->bcs) { + block_copy_set_speed(s->bcs, speed); + if (s->bg_bcs_call) { + block_copy_kick(s->bg_bcs_call); + } + } +} + +static bool backup_cancel(Job *job, bool force) +{ + BackupBlockJob *s = container_of(job, BackupBlockJob, common.job); + + bdrv_cancel_in_flight(s->target_bs); + return true; +} + +static const BlockJobDriver backup_job_driver = { + .job_driver = { + .instance_size = sizeof(BackupBlockJob), + .job_type = JOB_TYPE_BACKUP, + .free = block_job_free, + .user_resume = block_job_user_resume, + .run = backup_run, + .commit = backup_commit, + .abort = backup_abort, + .clean = backup_clean, + .pause = backup_pause, + .cancel = backup_cancel, + }, + .set_speed = backup_set_speed, +}; + +BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs, + BlockDriverState *target, int64_t speed, + MirrorSyncMode sync_mode, BdrvDirtyBitmap *sync_bitmap, + BitmapSyncMode bitmap_mode, + bool compress, + const char *filter_node_name, + BackupPerf *perf, + BlockdevOnError on_source_error, + BlockdevOnError on_target_error, + int creation_flags, + BlockCompletionFunc *cb, void *opaque, + JobTxn *txn, Error **errp) +{ + int64_t len, target_len; + BackupBlockJob *job = NULL; + int64_t cluster_size; + BlockDriverState *cbw = NULL; + BlockCopyState *bcs = NULL; + + assert(bs); + assert(target); + + /* QMP interface protects us from these cases */ + assert(sync_mode != MIRROR_SYNC_MODE_INCREMENTAL); + assert(sync_bitmap || sync_mode != MIRROR_SYNC_MODE_BITMAP); + + if (bs == target) { + error_setg(errp, "Source and target cannot be the same"); + return NULL; + } + + if (!bdrv_is_inserted(bs)) { + error_setg(errp, "Device is not inserted: %s", + bdrv_get_device_name(bs)); + return NULL; + } + + if (!bdrv_is_inserted(target)) { + error_setg(errp, "Device is not inserted: %s", + bdrv_get_device_name(target)); + return NULL; + } + + if (compress && !bdrv_supports_compressed_writes(target)) { + error_setg(errp, "Compression is not supported for this drive %s", + bdrv_get_device_name(target)); + return NULL; + } + + if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_BACKUP_SOURCE, errp)) { + return NULL; + } + + if (bdrv_op_is_blocked(target, BLOCK_OP_TYPE_BACKUP_TARGET, errp)) { + return NULL; + } + + if (perf->max_workers < 1 || perf->max_workers > INT_MAX) { + error_setg(errp, "max-workers must be between 1 and %d", INT_MAX); + return NULL; + } + + if (perf->max_chunk < 0) { + error_setg(errp, "max-chunk must be zero (which means no limit) or " + "positive"); + return NULL; + } + + if (sync_bitmap) { + /* If we need to write to this bitmap, check that we can: */ + if (bitmap_mode != BITMAP_SYNC_MODE_NEVER && + bdrv_dirty_bitmap_check(sync_bitmap, BDRV_BITMAP_DEFAULT, errp)) { + return NULL; + } + + /* Create a new bitmap, and freeze/disable this one. */ + if (bdrv_dirty_bitmap_create_successor(sync_bitmap, errp) < 0) { + return NULL; + } + } + + len = bdrv_getlength(bs); + if (len < 0) { + error_setg_errno(errp, -len, "Unable to get length for '%s'", + bdrv_get_device_or_node_name(bs)); + goto error; + } + + target_len = bdrv_getlength(target); + if (target_len < 0) { + error_setg_errno(errp, -target_len, "Unable to get length for '%s'", + bdrv_get_device_or_node_name(bs)); + goto error; + } + + if (target_len != len) { + error_setg(errp, "Source and target image have different sizes"); + goto error; + } + + cbw = bdrv_cbw_append(bs, target, filter_node_name, &bcs, errp); + if (!cbw) { + goto error; + } + + cluster_size = block_copy_cluster_size(bcs); + + if (perf->max_chunk && perf->max_chunk < cluster_size) { + error_setg(errp, "Required max-chunk (%" PRIi64 ") is less than backup " + "cluster size (%" PRIi64 ")", perf->max_chunk, cluster_size); + goto error; + } + + /* job->len is fixed, so we can't allow resize */ + job = block_job_create(job_id, &backup_job_driver, txn, cbw, + 0, BLK_PERM_ALL, + speed, creation_flags, cb, opaque, errp); + if (!job) { + goto error; + } + + job->cbw = cbw; + job->source_bs = bs; + job->target_bs = target; + job->on_source_error = on_source_error; + job->on_target_error = on_target_error; + job->sync_mode = sync_mode; + job->sync_bitmap = sync_bitmap; + job->bitmap_mode = bitmap_mode; + job->bcs = bcs; + job->cluster_size = cluster_size; + job->len = len; + job->perf = *perf; + + block_copy_set_copy_opts(bcs, perf->use_copy_range, compress); + block_copy_set_progress_meter(bcs, &job->common.job.progress); + block_copy_set_speed(bcs, speed); + + /* Required permissions are taken by copy-before-write filter target */ + block_job_add_bdrv(&job->common, "target", target, 0, BLK_PERM_ALL, + &error_abort); + + return &job->common; + + error: + if (sync_bitmap) { + bdrv_reclaim_dirty_bitmap(sync_bitmap, NULL); + } + if (cbw) { + bdrv_cbw_drop(cbw); + } + + return NULL; +} |