blockjob: Wrappers for progress counter access

Block job drivers are not expected to mess with the internals of the
BlockJob object, so provide wrapper functions for one of the cases where
they still do it: Updating the progress counter.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>

block/backup.c

@@ -39,6 +39,7 @@ typedef struct BackupBlockJob {
     BlockdevOnError on_source_error;
     BlockdevOnError on_target_error;
     CoRwlock flush_rwlock;
+    uint64_t len;
     uint64_t bytes_read;
     int64_t cluster_size;
     bool compress;
@@ -118,7 +119,7 @@ static int coroutine_fn backup_do_cow(BackupBlockJob *job,
 
         trace_backup_do_cow_process(job, start);
 
-        n = MIN(job->cluster_size, job->common.len - start);
+        n = MIN(job->cluster_size, job->len - start);
 
         if (!bounce_buffer) {
             bounce_buffer = blk_blockalign(blk, job->cluster_size);
@@ -159,7 +160,7 @@ static int coroutine_fn backup_do_cow(BackupBlockJob *job,
          * offset field is an opaque progress value, it is not a disk offset.
          */
         job->bytes_read += n;
-        job->common.offset += n;
+        block_job_progress_update(&job->common, n);
     }
 
 out:
@@ -261,7 +262,7 @@ void backup_do_checkpoint(BlockJob *job, Error **errp)
         return;
     }
 
-    len = DIV_ROUND_UP(backup_job->common.len, backup_job->cluster_size);
+    len = DIV_ROUND_UP(backup_job->len, backup_job->cluster_size);
     hbitmap_set(backup_job->copy_bitmap, 0, len);
 }
 
@@ -420,8 +421,9 @@ static void backup_incremental_init_copy_bitmap(BackupBlockJob *job)
         bdrv_set_dirty_iter(dbi, next_cluster * job->cluster_size);
     }
 
-    job->common.offset = job->common.len -
-                         hbitmap_count(job->copy_bitmap) * job->cluster_size;
+    /* TODO block_job_progress_set_remaining() would make more sense */
+    block_job_progress_update(&job->common,
+        job->len - hbitmap_count(job->copy_bitmap) * job->cluster_size);
 
     bdrv_dirty_iter_free(dbi);
 }
@@ -437,7 +439,9 @@ static void coroutine_fn backup_run(void *opaque)
     QLIST_INIT(&job->inflight_reqs);
     qemu_co_rwlock_init(&job->flush_rwlock);
 
-    nb_clusters = DIV_ROUND_UP(job->common.len, job->cluster_size);
+    nb_clusters = DIV_ROUND_UP(job->len, job->cluster_size);
+    block_job_progress_set_remaining(&job->common, job->len);
+
     job->copy_bitmap = hbitmap_alloc(nb_clusters, 0);
     if (job->sync_mode == MIRROR_SYNC_MODE_INCREMENTAL) {
         backup_incremental_init_copy_bitmap(job);
@@ -461,7 +465,7 @@ static void coroutine_fn backup_run(void *opaque)
         ret = backup_run_incremental(job);
     } else {
         /* Both FULL and TOP SYNC_MODE's require copying.. */
-        for (offset = 0; offset < job->common.len;
+        for (offset = 0; offset < job->len;
              offset += job->cluster_size) {
             bool error_is_read;
             int alloced = 0;
@@ -620,7 +624,7 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
         goto error;
     }
 
-    /* job->common.len is fixed, so we can't allow resize */
+    /* job->len is fixed, so we can't allow resize */
     job = block_job_create(job_id, &backup_job_driver, txn, bs,
                            BLK_PERM_CONSISTENT_READ,
                            BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE |
@@ -676,7 +680,7 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
     /* Required permissions are already taken with target's blk_new() */
     block_job_add_bdrv(&job->common, "target", target, 0, BLK_PERM_ALL,
                        &error_abort);
-    job->common.len = len;
+    job->len = len;
 
     return &job->common;
 

block/commit.c

@@ -146,21 +146,21 @@ static void coroutine_fn commit_run(void *opaque)
     int64_t n = 0; /* bytes */
     void *buf = NULL;
     int bytes_written = 0;
-    int64_t base_len;
+    int64_t len, base_len;
 
-    ret = s->common.len = blk_getlength(s->top);
-
-    if (s->common.len < 0) {
+    ret = len = blk_getlength(s->top);
+    if (len < 0) {
         goto out;
     }
+    block_job_progress_set_remaining(&s->common, len);
 
     ret = base_len = blk_getlength(s->base);
     if (base_len < 0) {
         goto out;
     }
 
-    if (base_len < s->common.len) {
-        ret = blk_truncate(s->base, s->common.len, PREALLOC_MODE_OFF, NULL);
+    if (base_len < len) {
+        ret = blk_truncate(s->base, len, PREALLOC_MODE_OFF, NULL);
         if (ret) {
             goto out;
         }
@@ -168,7 +168,7 @@ static void coroutine_fn commit_run(void *opaque)
 
     buf = blk_blockalign(s->top, COMMIT_BUFFER_SIZE);
 
-    for (offset = 0; offset < s->common.len; offset += n) {
+    for (offset = 0; offset < len; offset += n) {
         bool copy;
 
         /* Note that even when no rate limit is applied we need to yield
@@ -198,7 +198,7 @@ static void coroutine_fn commit_run(void *opaque)
             }
         }
         /* Publish progress */
-        s->common.offset += n;
+        block_job_progress_update(&s->common, n);
 
         if (copy && s->common.speed) {
             delay_ns = ratelimit_calculate_delay(&s->limit, n);

block/mirror.c

@@ -121,7 +121,7 @@ static void mirror_iteration_done(MirrorOp *op, int ret)
             bitmap_set(s->cow_bitmap, chunk_num, nb_chunks);
         }
         if (!s->initial_zeroing_ongoing) {
-            s->common.offset += op->bytes;
+            block_job_progress_update(&s->common, op->bytes);
         }
     }
     qemu_iovec_destroy(&op->qiov);
@@ -792,11 +792,10 @@ static void coroutine_fn mirror_run(void *opaque)
         block_job_pause_point(&s->common);
 
         cnt = bdrv_get_dirty_count(s->dirty_bitmap);
-        /* s->common.offset contains the number of bytes already processed so
-         * far, cnt is the number of dirty bytes remaining and
-         * s->bytes_in_flight is the number of bytes currently being
-         * processed; together those are the current total operation length */
-        s->common.len = s->common.offset + s->bytes_in_flight + cnt;
+        /* cnt is the number of dirty bytes remaining and s->bytes_in_flight is
+         * the number of bytes currently being processed; together those are
+         * the current remaining operation length */
+        block_job_progress_set_remaining(&s->common, s->bytes_in_flight + cnt);
 
         /* Note that even when no rate limit is applied we need to yield
          * periodically with no pending I/O so that bdrv_drain_all() returns.

block/stream.c

@@ -107,6 +107,7 @@ static void coroutine_fn stream_run(void *opaque)
     BlockBackend *blk = s->common.blk;
     BlockDriverState *bs = blk_bs(blk);
     BlockDriverState *base = s->base;
+    int64_t len;
     int64_t offset = 0;
     uint64_t delay_ns = 0;
     int error = 0;
@@ -118,11 +119,12 @@ static void coroutine_fn stream_run(void *opaque)
         goto out;
     }
 
-    s->common.len = bdrv_getlength(bs);
-    if (s->common.len < 0) {
-        ret = s->common.len;
+    len = bdrv_getlength(bs);
+    if (len < 0) {
+        ret = len;
         goto out;
     }
+    block_job_progress_set_remaining(&s->common, len);
 
     buf = qemu_blockalign(bs, STREAM_BUFFER_SIZE);
 
@@ -135,7 +137,7 @@ static void coroutine_fn stream_run(void *opaque)
         bdrv_enable_copy_on_read(bs);
     }
 
-    for ( ; offset < s->common.len; offset += n) {
+    for ( ; offset < len; offset += n) {
         bool copy;
 
         /* Note that even when no rate limit is applied we need to yield
@@ -159,7 +161,7 @@ static void coroutine_fn stream_run(void *opaque)
 
             /* Finish early if end of backing file has been reached */
             if (ret == 0 && n == 0) {
-                n = s->common.len - offset;
+                n = len - offset;
             }
 
             copy = (ret == 1);
@@ -185,7 +187,7 @@ static void coroutine_fn stream_run(void *opaque)
         ret = 0;
 
         /* Publish progress */
-        s->common.offset += n;
+        block_job_progress_update(&s->common, n);
         if (copy && s->common.speed) {
             delay_ns = ratelimit_calculate_delay(&s->limit, n);
         } else {

blockjob.c

@@ -810,6 +810,16 @@ int block_job_complete_sync(BlockJob *job, Error **errp)
     return block_job_finish_sync(job, &block_job_complete, errp);
 }
 
+void block_job_progress_update(BlockJob *job, uint64_t done)
+{
+    job->offset += done;
+}
+
+void block_job_progress_set_remaining(BlockJob *job, uint64_t remaining)
+{
+    job->len = job->offset + remaining;
+}
+
 BlockJobInfo *block_job_query(BlockJob *job, Error **errp)
 {
     BlockJobInfo *info;

include/block/blockjob.h

@@ -277,6 +277,25 @@ void block_job_finalize(BlockJob *job, Error **errp);
  */
 void block_job_dismiss(BlockJob **job, Error **errp);
 
+/**
+ * block_job_progress_update:
+ * @job: The job that has made progress
+ * @done: How much progress the job made
+ *
+ * Updates the progress counter of the job.
+ */
+void block_job_progress_update(BlockJob *job, uint64_t done);
+
+/**
+ * block_job_progress_set_remaining:
+ * @job: The job whose expected progress end value is set
+ * @remaining: Expected end value of the progress counter of the job
+ *
+ * Sets the expected end value of the progress counter of a job so that a
+ * completion percentage can be calculated when the progress is updated.
+ */
+void block_job_progress_set_remaining(BlockJob *job, uint64_t remaining);
+
 /**
  * block_job_query:
  * @job: The job to get information about.