diff options
| -rw-r--r-- | block/mirror.c | 44 | ||||
| -rw-r--r-- | qapi/block-core.json | 13 |
2 files changed, 53 insertions, 4 deletions
diff --git a/block/mirror.c b/block/mirror.c index 31da1526eb..4016d89253 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -55,6 +55,10 @@ typedef struct MirrorBlockJob { BlockMirrorBackingMode backing_mode; /* Whether the target image requires explicit zero-initialization */ bool zero_target; + /* + * To be accesssed with atomics. Written only under the BQL (required by the + * current implementation of mirror_change()). + */ MirrorCopyMode copy_mode; BlockdevOnError on_source_error, on_target_error; /* Set when the target is synced (dirty bitmap is clean, nothing @@ -1075,7 +1079,7 @@ static int coroutine_fn mirror_run(Job *job, Error **errp) */ job_transition_to_ready(&s->common.job); } - if (s->copy_mode != MIRROR_COPY_MODE_BACKGROUND) { + if (qatomic_read(&s->copy_mode) != MIRROR_COPY_MODE_BACKGROUND) { s->actively_synced = true; } @@ -1246,6 +1250,39 @@ static bool commit_active_cancel(Job *job, bool force) return force || !job_is_ready(job); } +static void mirror_change(BlockJob *job, BlockJobChangeOptions *opts, + Error **errp) +{ + MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); + BlockJobChangeOptionsMirror *change_opts = &opts->u.mirror; + MirrorCopyMode current; + + /* + * The implementation relies on the fact that copy_mode is only written + * under the BQL. Otherwise, further synchronization would be required. + */ + + GLOBAL_STATE_CODE(); + + if (qatomic_read(&s->copy_mode) == change_opts->copy_mode) { + return; + } + + if (change_opts->copy_mode != MIRROR_COPY_MODE_WRITE_BLOCKING) { + error_setg(errp, "Change to copy mode '%s' is not implemented", + MirrorCopyMode_str(change_opts->copy_mode)); + return; + } + + current = qatomic_cmpxchg(&s->copy_mode, MIRROR_COPY_MODE_BACKGROUND, + change_opts->copy_mode); + if (current != MIRROR_COPY_MODE_BACKGROUND) { + error_setg(errp, "Expected current copy mode '%s', got '%s'", + MirrorCopyMode_str(MIRROR_COPY_MODE_BACKGROUND), + MirrorCopyMode_str(current)); + } +} + static const BlockJobDriver mirror_job_driver = { .job_driver = { .instance_size = sizeof(MirrorBlockJob), @@ -1260,6 +1297,7 @@ static const BlockJobDriver mirror_job_driver = { .cancel = mirror_cancel, }, .drained_poll = mirror_drained_poll, + .change = mirror_change, }; static const BlockJobDriver commit_active_job_driver = { @@ -1467,7 +1505,7 @@ static bool should_copy_to_target(MirrorBDSOpaque *s) { return s->job && s->job->ret >= 0 && !job_is_cancelled(&s->job->common.job) && - s->job->copy_mode == MIRROR_COPY_MODE_WRITE_BLOCKING; + qatomic_read(&s->job->copy_mode) == MIRROR_COPY_MODE_WRITE_BLOCKING; } static int coroutine_fn GRAPH_RDLOCK @@ -1813,7 +1851,7 @@ static BlockJob *mirror_start_job( s->is_none_mode = is_none_mode; s->backing_mode = backing_mode; s->zero_target = zero_target; - s->copy_mode = copy_mode; + qatomic_set(&s->copy_mode, copy_mode); s->base = base; s->base_overlay = bdrv_find_overlay(bs, base); s->granularity = granularity; diff --git a/qapi/block-core.json b/qapi/block-core.json index c6f31a9399..6369207be2 100644 --- a/qapi/block-core.json +++ b/qapi/block-core.json @@ -3045,6 +3045,17 @@ 'allow-preconfig': true } ## +# @BlockJobChangeOptionsMirror: +# +# @copy-mode: Switch to this copy mode. Currently, only the switch +# from 'background' to 'write-blocking' is implemented. +# +# Since: 8.2 +## +{ 'struct': 'BlockJobChangeOptionsMirror', + 'data': { 'copy-mode' : 'MirrorCopyMode' } } + +## # @BlockJobChangeOptions: # # Block job options that can be changed after job creation. @@ -3058,7 +3069,7 @@ { 'union': 'BlockJobChangeOptions', 'base': { 'id': 'str', 'type': 'JobType' }, 'discriminator': 'type', - 'data': {} } + 'data': { 'mirror': 'BlockJobChangeOptionsMirror' } } ## # @block-job-change: |