/* * Replication Block filter * * Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD. * Copyright (c) 2016 Intel Corporation * Copyright (c) 2016 FUJITSU LIMITED * * Author: * Wen Congyang <wency@cn.fujitsu.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 "qemu/option.h" #include "block/nbd.h" #include "block/blockjob.h" #include "block/block_int.h" #include "block/block_backup.h" #include "sysemu/block-backend.h" #include "qapi/error.h" #include "replication.h" typedef enum { BLOCK_REPLICATION_NONE, /* block replication is not started */ BLOCK_REPLICATION_RUNNING, /* block replication is running */ BLOCK_REPLICATION_FAILOVER, /* failover is running in background */ BLOCK_REPLICATION_FAILOVER_FAILED, /* failover failed */ BLOCK_REPLICATION_DONE, /* block replication is done */ } ReplicationStage; typedef struct BDRVReplicationState { ReplicationMode mode; ReplicationStage stage; BdrvChild *active_disk; BdrvChild *hidden_disk; BdrvChild *secondary_disk; char *top_id; ReplicationState *rs; Error *blocker; int orig_hidden_flags; int orig_secondary_flags; int error; } BDRVReplicationState; static void replication_start(ReplicationState *rs, ReplicationMode mode, Error **errp); static void replication_do_checkpoint(ReplicationState *rs, Error **errp); static void replication_get_error(ReplicationState *rs, Error **errp); static void replication_stop(ReplicationState *rs, bool failover, Error **errp); #define REPLICATION_MODE "mode" #define REPLICATION_TOP_ID "top-id" static QemuOptsList replication_runtime_opts = { .name = "replication", .head = QTAILQ_HEAD_INITIALIZER(replication_runtime_opts.head), .desc = { { .name = REPLICATION_MODE, .type = QEMU_OPT_STRING, }, { .name = REPLICATION_TOP_ID, .type = QEMU_OPT_STRING, }, { /* end of list */ } }, }; static ReplicationOps replication_ops = { .start = replication_start, .checkpoint = replication_do_checkpoint, .get_error = replication_get_error, .stop = replication_stop, }; static int replication_open(BlockDriverState *bs, QDict *options, int flags, Error **errp) { int ret; BDRVReplicationState *s = bs->opaque; Error *local_err = NULL; QemuOpts *opts = NULL; const char *mode; const char *top_id; bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, false, errp); if (!bs->file) { return -EINVAL; } ret = -EINVAL; opts = qemu_opts_create(&replication_runtime_opts, NULL, 0, &error_abort); qemu_opts_absorb_qdict(opts, options, &local_err); if (local_err) { goto fail; } mode = qemu_opt_get(opts, REPLICATION_MODE); if (!mode) { error_setg(&local_err, "Missing the option mode"); goto fail; } if (!strcmp(mode, "primary")) { s->mode = REPLICATION_MODE_PRIMARY; top_id = qemu_opt_get(opts, REPLICATION_TOP_ID); if (top_id) { error_setg(&local_err, "The primary side does not support option top-id"); goto fail; } } else if (!strcmp(mode, "secondary")) { s->mode = REPLICATION_MODE_SECONDARY; top_id = qemu_opt_get(opts, REPLICATION_TOP_ID); s->top_id = g_strdup(top_id); if (!s->top_id) { error_setg(&local_err, "Missing the option top-id"); goto fail; } } else { error_setg(&local_err, "The option mode's value should be primary or secondary"); goto fail; } s->rs = replication_new(bs, &replication_ops); ret = 0; fail: qemu_opts_del(opts); error_propagate(errp, local_err); return ret; } static void replication_close(BlockDriverState *bs) { BDRVReplicationState *s = bs->opaque; if (s->stage == BLOCK_REPLICATION_RUNNING) { replication_stop(s->rs, false, NULL); } if (s->stage == BLOCK_REPLICATION_FAILOVER) { block_job_cancel_sync(s->active_disk->bs->job); } if (s->mode == REPLICATION_MODE_SECONDARY) { g_free(s->top_id); } replication_remove(s->rs); } static void replication_child_perm(BlockDriverState *bs, BdrvChild *c, const BdrvChildRole *role, BlockReopenQueue *reopen_queue, uint64_t perm, uint64_t shared, uint64_t *nperm, uint64_t *nshared) { *nperm = BLK_PERM_CONSISTENT_READ; if ((bs->open_flags & (BDRV_O_INACTIVE | BDRV_O_RDWR)) == BDRV_O_RDWR) { *nperm |= BLK_PERM_WRITE; } *nshared = BLK_PERM_CONSISTENT_READ \ | BLK_PERM_WRITE \ | BLK_PERM_WRITE_UNCHANGED; return; } static int64_t replication_getlength(BlockDriverState *bs) { return bdrv_getlength(bs->file->bs); } static int replication_get_io_status(BDRVReplicationState *s) { switch (s->stage) { case BLOCK_REPLICATION_NONE: return -EIO; case BLOCK_REPLICATION_RUNNING: return 0; case BLOCK_REPLICATION_FAILOVER: return s->mode == REPLICATION_MODE_PRIMARY ? -EIO : 0; case BLOCK_REPLICATION_FAILOVER_FAILED: return s->mode == REPLICATION_MODE_PRIMARY ? -EIO : 1; case BLOCK_REPLICATION_DONE: /* * active commit job completes, and active disk and secondary_disk * is swapped, so we can operate bs->file directly */ return s->mode == REPLICATION_MODE_PRIMARY ? -EIO : 0; default: abort(); } } static int replication_return_value(BDRVReplicationState *s, int ret) { if (s->mode == REPLICATION_MODE_SECONDARY) { return ret; } if (ret < 0) { s->error = ret; ret = 0; } return ret; } static coroutine_fn int replication_co_readv(BlockDriverState *bs, int64_t sector_num, int remaining_sectors, QEMUIOVector *qiov) { BDRVReplicationState *s = bs->opaque; BdrvChild *child = s->secondary_disk; BlockJob *job = NULL; CowRequest req; int ret; if (s->mode == REPLICATION_MODE_PRIMARY) { /* We only use it to forward primary write requests */ return -EIO; } ret = replication_get_io_status(s); if (ret < 0) { return ret; } if (child && child->bs) { job = child->bs->job; } if (job) { uint64_t remaining_bytes = remaining_sectors * BDRV_SECTOR_SIZE; backup_wait_for_overlapping_requests(child->bs->job, sector_num * BDRV_SECTOR_SIZE, remaining_bytes); backup_cow_request_begin(&req, child->bs->job, sector_num * BDRV_SECTOR_SIZE, remaining_bytes); ret = bdrv_co_readv(bs->file, sector_num, remaining_sectors, qiov); backup_cow_request_end(&req); goto out; } ret = bdrv_co_readv(bs->file, sector_num, remaining_sectors, qiov); out: return replication_return_value(s, ret); } static coroutine_fn int replication_co_writev(BlockDriverState *bs, int64_t sector_num, int remaining_sectors, QEMUIOVector *qiov) { BDRVReplicationState *s = bs->opaque; QEMUIOVector hd_qiov; uint64_t bytes_done = 0; BdrvChild *top = bs->file; BdrvChild *base = s->secondary_disk; BdrvChild *target; int ret; int64_t n; ret = replication_get_io_status(s); if (ret < 0) { goto out; } if (ret == 0) { ret = bdrv_co_writev(top, sector_num, remaining_sectors, qiov); return replication_return_value(s, ret); } /* * Failover failed, only write to active disk if the sectors * have already been allocated in active disk/hidden disk. */ qemu_iovec_init(&hd_qiov, qiov->niov); while (remaining_sectors > 0) { int64_t count; ret = bdrv_is_allocated_above(top->bs, base->bs, sector_num * BDRV_SECTOR_SIZE, remaining_sectors * BDRV_SECTOR_SIZE, &count); if (ret < 0) { goto out1; } assert(QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE)); n = count >> BDRV_SECTOR_BITS; qemu_iovec_reset(&hd_qiov); qemu_iovec_concat(&hd_qiov, qiov, bytes_done, count); target = ret ? top : base; ret = bdrv_co_writev(target, sector_num, n, &hd_qiov); if (ret < 0) { goto out1; } remaining_sectors -= n; sector_num += n; bytes_done += count; } out1: qemu_iovec_destroy(&hd_qiov); out: return ret; } static bool replication_recurse_is_first_non_filter(BlockDriverState *bs, BlockDriverState *candidate) { return bdrv_recurse_is_first_non_filter(bs->file->bs, candidate); } static void secondary_do_checkpoint(BDRVReplicationState *s, Error **errp) { Error *local_err = NULL; int ret; if (!s->secondary_disk->bs->job) { error_setg(errp, "Backup job was cancelled unexpectedly"); return; } backup_do_checkpoint(s->secondary_disk->bs->job, &local_err); if (local_err) { error_propagate(errp, local_err); return; } if (!s->active_disk->bs->drv) { error_setg(errp, "Active disk %s is ejected", s->active_disk->bs->node_name); return; } ret = s->active_disk->bs->drv->bdrv_make_empty(s->active_disk->bs); if (ret < 0) { error_setg(errp, "Cannot make active disk empty"); return; } if (!s->hidden_disk->bs->drv) { error_setg(errp, "Hidden disk %s is ejected", s->hidden_disk->bs->node_name); return; } ret = s->hidden_disk->bs->drv->bdrv_make_empty(s->hidden_disk->bs); if (ret < 0) { error_setg(errp, "Cannot make hidden disk empty"); return; } } static void reopen_backing_file(BlockDriverState *bs, bool writable, Error **errp) { BDRVReplicationState *s = bs->opaque; BlockReopenQueue *reopen_queue = NULL; int orig_hidden_flags, orig_secondary_flags; int new_hidden_flags, new_secondary_flags; Error *local_err = NULL; if (writable) { orig_hidden_flags = s->orig_hidden_flags = bdrv_get_flags(s->hidden_disk->bs); new_hidden_flags = (orig_hidden_flags | BDRV_O_RDWR) & ~BDRV_O_INACTIVE; orig_secondary_flags = s->orig_secondary_flags = bdrv_get_flags(s->secondary_disk->bs); new_secondary_flags = (orig_secondary_flags | BDRV_O_RDWR) & ~BDRV_O_INACTIVE; } else { orig_hidden_flags = (s->orig_hidden_flags | BDRV_O_RDWR) & ~BDRV_O_INACTIVE; new_hidden_flags = s->orig_hidden_flags; orig_secondary_flags = (s->orig_secondary_flags | BDRV_O_RDWR) & ~BDRV_O_INACTIVE; new_secondary_flags = s->orig_secondary_flags; } bdrv_subtree_drained_begin(s->hidden_disk->bs); bdrv_subtree_drained_begin(s->secondary_disk->bs); if (orig_hidden_flags != new_hidden_flags) { reopen_queue = bdrv_reopen_queue(reopen_queue, s->hidden_disk->bs, NULL, new_hidden_flags); } if (!(orig_secondary_flags & BDRV_O_RDWR)) { reopen_queue = bdrv_reopen_queue(reopen_queue, s->secondary_disk->bs, NULL, new_secondary_flags); } if (reopen_queue) { bdrv_reopen_multiple(bdrv_get_aio_context(bs), reopen_queue, &local_err); error_propagate(errp, local_err); } bdrv_subtree_drained_end(s->hidden_disk->bs); bdrv_subtree_drained_end(s->secondary_disk->bs); } static void backup_job_cleanup(BlockDriverState *bs) { BDRVReplicationState *s = bs->opaque; BlockDriverState *top_bs; top_bs = bdrv_lookup_bs(s->top_id, s->top_id, NULL); if (!top_bs) { return; } bdrv_op_unblock_all(top_bs, s->blocker); error_free(s->blocker); reopen_backing_file(bs, false, NULL); } static void backup_job_completed(void *opaque, int ret) { BlockDriverState *bs = opaque; BDRVReplicationState *s = bs->opaque; if (s->stage != BLOCK_REPLICATION_FAILOVER) { /* The backup job is cancelled unexpectedly */ s->error = -EIO; } backup_job_cleanup(bs); } static bool check_top_bs(BlockDriverState *top_bs, BlockDriverState *bs) { BdrvChild *child; /* The bs itself is the top_bs */ if (top_bs == bs) { return true; } /* Iterate over top_bs's children */ QLIST_FOREACH(child, &top_bs->children, next) { if (child->bs == bs || check_top_bs(child->bs, bs)) { return true; } } return false; } static void replication_start(ReplicationState *rs, ReplicationMode mode, Error **errp) { BlockDriverState *bs = rs->opaque; BDRVReplicationState *s; BlockDriverState *top_bs; int64_t active_length, hidden_length, disk_length; AioContext *aio_context; Error *local_err = NULL; BlockJob *job; aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); s = bs->opaque; if (s->stage != BLOCK_REPLICATION_NONE) { error_setg(errp, "Block replication is running or done"); aio_context_release(aio_context); return; } if (s->mode != mode) { error_setg(errp, "The parameter mode's value is invalid, needs %d," " but got %d", s->mode, mode); aio_context_release(aio_context); return; } switch (s->mode) { case REPLICATION_MODE_PRIMARY: break; case REPLICATION_MODE_SECONDARY: s->active_disk = bs->file; if (!s->active_disk || !s->active_disk->bs || !s->active_disk->bs->backing) { error_setg(errp, "Active disk doesn't have backing file"); aio_context_release(aio_context); return; } s->hidden_disk = s->active_disk->bs->backing; if (!s->hidden_disk->bs || !s->hidden_disk->bs->backing) { error_setg(errp, "Hidden disk doesn't have backing file"); aio_context_release(aio_context); return; } s->secondary_disk = s->hidden_disk->bs->backing; if (!s->secondary_disk->bs || !bdrv_has_blk(s->secondary_disk->bs)) { error_setg(errp, "The secondary disk doesn't have block backend"); aio_context_release(aio_context); return; } /* verify the length */ active_length = bdrv_getlength(s->active_disk->bs); hidden_length = bdrv_getlength(s->hidden_disk->bs); disk_length = bdrv_getlength(s->secondary_disk->bs); if (active_length < 0 || hidden_length < 0 || disk_length < 0 || active_length != hidden_length || hidden_length != disk_length) { error_setg(errp, "Active disk, hidden disk, secondary disk's length" " are not the same"); aio_context_release(aio_context); return; } /* Must be true, or the bdrv_getlength() calls would have failed */ assert(s->active_disk->bs->drv && s->hidden_disk->bs->drv); if (!s->active_disk->bs->drv->bdrv_make_empty || !s->hidden_disk->bs->drv->bdrv_make_empty) { error_setg(errp, "Active disk or hidden disk doesn't support make_empty"); aio_context_release(aio_context); return; } /* reopen the backing file in r/w mode */ reopen_backing_file(bs, true, &local_err); if (local_err) { error_propagate(errp, local_err); aio_context_release(aio_context); return; } /* start backup job now */ error_setg(&s->blocker, "Block device is in use by internal backup job"); top_bs = bdrv_lookup_bs(s->top_id, s->top_id, NULL); if (!top_bs || !bdrv_is_root_node(top_bs) || !check_top_bs(top_bs, bs)) { error_setg(errp, "No top_bs or it is invalid"); reopen_backing_file(bs, false, NULL); aio_context_release(aio_context); return; } bdrv_op_block_all(top_bs, s->blocker); bdrv_op_unblock(top_bs, BLOCK_OP_TYPE_DATAPLANE, s->blocker); job = backup_job_create(NULL, s->secondary_disk->bs, s->hidden_disk->bs, 0, MIRROR_SYNC_MODE_NONE, NULL, false, BLOCKDEV_ON_ERROR_REPORT, BLOCKDEV_ON_ERROR_REPORT, BLOCK_JOB_INTERNAL, backup_job_completed, bs, NULL, &local_err); if (local_err) { error_propagate(errp, local_err); backup_job_cleanup(bs); aio_context_release(aio_context); return; } block_job_start(job); break; default: aio_context_release(aio_context); abort(); } s->stage = BLOCK_REPLICATION_RUNNING; if (s->mode == REPLICATION_MODE_SECONDARY) { secondary_do_checkpoint(s, errp); } s->error = 0; aio_context_release(aio_context); } static void replication_do_checkpoint(ReplicationState *rs, Error **errp) { BlockDriverState *bs = rs->opaque; BDRVReplicationState *s; AioContext *aio_context; aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); s = bs->opaque; if (s->mode == REPLICATION_MODE_SECONDARY) { secondary_do_checkpoint(s, errp); } aio_context_release(aio_context); } static void replication_get_error(ReplicationState *rs, Error **errp) { BlockDriverState *bs = rs->opaque; BDRVReplicationState *s; AioContext *aio_context; aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); s = bs->opaque; if (s->stage != BLOCK_REPLICATION_RUNNING) { error_setg(errp, "Block replication is not running"); aio_context_release(aio_context); return; } if (s->error) { error_setg(errp, "I/O error occurred"); aio_context_release(aio_context); return; } aio_context_release(aio_context); } static void replication_done(void *opaque, int ret) { BlockDriverState *bs = opaque; BDRVReplicationState *s = bs->opaque; if (ret == 0) { s->stage = BLOCK_REPLICATION_DONE; /* refresh top bs's filename */ bdrv_refresh_filename(bs); s->active_disk = NULL; s->secondary_disk = NULL; s->hidden_disk = NULL; s->error = 0; } else { s->stage = BLOCK_REPLICATION_FAILOVER_FAILED; s->error = -EIO; } } static void replication_stop(ReplicationState *rs, bool failover, Error **errp) { BlockDriverState *bs = rs->opaque; BDRVReplicationState *s; AioContext *aio_context; aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); s = bs->opaque; if (s->stage != BLOCK_REPLICATION_RUNNING) { error_setg(errp, "Block replication is not running"); aio_context_release(aio_context); return; } switch (s->mode) { case REPLICATION_MODE_PRIMARY: s->stage = BLOCK_REPLICATION_DONE; s->error = 0; break; case REPLICATION_MODE_SECONDARY: /* * This BDS will be closed, and the job should be completed * before the BDS is closed, because we will access hidden * disk, secondary disk in backup_job_completed(). */ if (s->secondary_disk->bs->job) { block_job_cancel_sync(s->secondary_disk->bs->job); } if (!failover) { secondary_do_checkpoint(s, errp); s->stage = BLOCK_REPLICATION_DONE; aio_context_release(aio_context); return; } s->stage = BLOCK_REPLICATION_FAILOVER; commit_active_start(NULL, s->active_disk->bs, s->secondary_disk->bs, BLOCK_JOB_INTERNAL, 0, BLOCKDEV_ON_ERROR_REPORT, NULL, replication_done, bs, true, errp); break; default: aio_context_release(aio_context); abort(); } aio_context_release(aio_context); } BlockDriver bdrv_replication = { .format_name = "replication", .protocol_name = "replication", .instance_size = sizeof(BDRVReplicationState), .bdrv_open = replication_open, .bdrv_close = replication_close, .bdrv_child_perm = replication_child_perm, .bdrv_getlength = replication_getlength, .bdrv_co_readv = replication_co_readv, .bdrv_co_writev = replication_co_writev, .is_filter = true, .bdrv_recurse_is_first_non_filter = replication_recurse_is_first_non_filter, .has_variable_length = true, }; static void bdrv_replication_init(void) { bdrv_register(&bdrv_replication); } block_init(bdrv_replication_init);