backup: Use BlockBackend for I/O

This changes the backup block job to use the job's BlockBackend for performing its I/O. job->bs isn't used by the backup code any more afterwards. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
2024-11-23 10:53:37 +08:00 · 2016-04-14 13:09:53 +02:00 · 2016-04-14 13:09:53 +02:00 · 5c438bc68c
commit 5c438bc68c
parent 8543c27414
5 changed files with 22 additions and 40 deletions
--- a/block/backup.c
+++ b/block/backup.c
@ -36,7 +36,7 @@ typedef struct CowRequest {

 typedef struct BackupBlockJob {
    BlockJob common;
-    BlockDriverState *target;
+    BlockBackend *target;
    /* bitmap for sync=incremental */
    BdrvDirtyBitmap *sync_bitmap;
    MirrorSyncMode sync_mode;
@ -99,7 +99,7 @@ static int coroutine_fn backup_do_cow(BackupBlockJob *job,
                                      bool *error_is_read,
                                      bool is_write_notifier)
 {
-    BlockDriverState *bs = job->common.bs;
+    BlockBackend *blk = job->common.blk;
    CowRequest cow_request;
    struct iovec iov;
    QEMUIOVector bounce_qiov;
@ -132,20 +132,15 @@ static int coroutine_fn backup_do_cow(BackupBlockJob *job,
                start * sectors_per_cluster);

        if (!bounce_buffer) {
-            bounce_buffer = qemu_blockalign(bs, job->cluster_size);
+            bounce_buffer = blk_blockalign(blk, job->cluster_size);
        }
        iov.iov_base = bounce_buffer;
        iov.iov_len = n * BDRV_SECTOR_SIZE;
        qemu_iovec_init_external(&bounce_qiov, &iov, 1);

-        if (is_write_notifier) {
-            ret = bdrv_co_readv_no_serialising(bs,
-                                           start * sectors_per_cluster,
-                                           n, &bounce_qiov);
-        } else {
-            ret = bdrv_co_readv(bs, start * sectors_per_cluster, n,
-                                &bounce_qiov);
-        }
+        ret = blk_co_preadv(blk, start * job->cluster_size,
+                            bounce_qiov.size, &bounce_qiov,
+                            is_write_notifier ? BDRV_REQ_NO_SERIALISING : 0);
        if (ret < 0) {
            trace_backup_do_cow_read_fail(job, start, ret);
            if (error_is_read) {
@ -155,13 +150,11 @@ static int coroutine_fn backup_do_cow(BackupBlockJob *job,
        }

        if (buffer_is_zero(iov.iov_base, iov.iov_len)) {
-            ret = bdrv_co_write_zeroes(job->target,
-                                       start * sectors_per_cluster,
-                                       n, BDRV_REQ_MAY_UNMAP);
+            ret = blk_co_pwrite_zeroes(job->target, start * job->cluster_size,
+                                       bounce_qiov.size, BDRV_REQ_MAY_UNMAP);
        } else {
-            ret = bdrv_co_writev(job->target,
-                                 start * sectors_per_cluster, n,
-                                 &bounce_qiov);
+            ret = blk_co_pwritev(job->target, start * job->cluster_size,
+                                 bounce_qiov.size, &bounce_qiov, 0);
        }
        if (ret < 0) {
            trace_backup_do_cow_write_fail(job, start, ret);
@ -203,7 +196,7 @@ static int coroutine_fn backup_before_write_notify(
    int64_t sector_num = req->offset >> BDRV_SECTOR_BITS;
    int nb_sectors = req->bytes >> BDRV_SECTOR_BITS;

-    assert(req->bs == job->common.bs);
+    assert(req->bs == blk_bs(job->common.blk));
    assert((req->offset & (BDRV_SECTOR_SIZE - 1)) == 0);
    assert((req->bytes & (BDRV_SECTOR_SIZE - 1)) == 0);

@ -224,7 +217,7 @@ static void backup_set_speed(BlockJob *job, int64_t speed, Error **errp)
 static void backup_cleanup_sync_bitmap(BackupBlockJob *job, int ret)
 {
    BdrvDirtyBitmap *bm;
-    BlockDriverState *bs = job->common.bs;
+    BlockDriverState *bs = blk_bs(job->common.blk);

    if (ret < 0 || block_job_is_cancelled(&job->common)) {
        /* Merge the successor back into the parent, delete nothing. */
@ -282,7 +275,7 @@ static void backup_complete(BlockJob *job, void *opaque)
    BackupBlockJob *s = container_of(job, BackupBlockJob, common);
    BackupCompleteData *data = opaque;

-    bdrv_unref(s->target);
+    blk_unref(s->target);

    block_job_completed(job, data->ret);
    g_free(data);
@ -378,8 +371,8 @@ static void coroutine_fn backup_run(void *opaque)
 {
    BackupBlockJob *job = opaque;
    BackupCompleteData *data;
-    BlockDriverState *bs = job->common.bs;
-    BlockDriverState *target = job->target;
+    BlockDriverState *bs = blk_bs(job->common.blk);
+    BlockBackend *target = job->target;
    int64_t start, end;
    int64_t sectors_per_cluster = cluster_size_sectors(job);
    int ret = 0;
@ -468,7 +461,7 @@ static void coroutine_fn backup_run(void *opaque)
    qemu_co_rwlock_unlock(&job->flush_rwlock);
    g_free(job->done_bitmap);

-    bdrv_op_unblock_all(target, job->common.blocker);
+    bdrv_op_unblock_all(blk_bs(target), job->common.blocker);

    data = g_malloc(sizeof(*data));
    data->ret = ret;
@ -548,9 +541,11 @@ void backup_start(BlockDriverState *bs, BlockDriverState *target,
        goto error;
    }

+    job->target = blk_new();
+    blk_insert_bs(job->target, target);
+
    job->on_source_error = on_source_error;
    job->on_target_error = on_target_error;
-    job->target = target;
    job->sync_mode = sync_mode;
    job->sync_bitmap = sync_mode == MIRROR_SYNC_MODE_INCREMENTAL ?
                       sync_bitmap : NULL;
@ -558,7 +553,7 @@ void backup_start(BlockDriverState *bs, BlockDriverState *target,
    /* If there is no backing file on the target, we cannot rely on COW if our
     * backup cluster size is smaller than the target cluster size. Even for
     * targets with a backing file, try to avoid COW if possible. */
-    ret = bdrv_get_info(job->target, &bdi);
+    ret = bdrv_get_info(target, &bdi);
    if (ret < 0 && !target->backing) {
        error_setg_errno(errp, -ret,
            "Couldn't determine the cluster size of the target image, "
@ -585,6 +580,7 @@ void backup_start(BlockDriverState *bs, BlockDriverState *target,
        bdrv_reclaim_dirty_bitmap(bs, sync_bitmap, NULL);
    }
    if (job) {
+        blk_unref(job->target);
        block_job_unref(&job->common);
    }
 }
--- a/block/io.c
+++ b/block/io.c
@ -1108,15 +1108,6 @@ int coroutine_fn bdrv_co_readv(BlockDriverState *bs, int64_t sector_num,
    return bdrv_co_do_readv(bs, sector_num, nb_sectors, qiov, 0);
 }

-int coroutine_fn bdrv_co_readv_no_serialising(BlockDriverState *bs,
-    int64_t sector_num, int nb_sectors, QEMUIOVector *qiov)
-{
-    trace_bdrv_co_readv_no_serialising(bs, sector_num, nb_sectors);
-
-    return bdrv_co_do_readv(bs, sector_num, nb_sectors, qiov,
-                            BDRV_REQ_NO_SERIALISING);
-}
-
 #define MAX_WRITE_ZEROES_BOUNCE_BUFFER 32768

 static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs,
--- a/blockdev.c
+++ b/blockdev.c
@ -3293,8 +3293,8 @@ static void do_drive_backup(const char *device, const char *target,
    backup_start(bs, target_bs, speed, sync, bmap,
                 on_source_error, on_target_error,
                 block_job_cb, bs, txn, &local_err);
+    bdrv_unref(target_bs);
    if (local_err != NULL) {
-        bdrv_unref(target_bs);
        error_propagate(errp, local_err);
        goto out;
    }
@ -3378,12 +3378,10 @@ void do_blockdev_backup(const char *device, const char *target,
    }
    target_bs = blk_bs(target_blk);

-    bdrv_ref(target_bs);
    bdrv_set_aio_context(target_bs, aio_context);
    backup_start(bs, target_bs, speed, sync, NULL, on_source_error,
                 on_target_error, block_job_cb, bs, txn, &local_err);
    if (local_err != NULL) {
-        bdrv_unref(target_bs);
        error_propagate(errp, local_err);
    }
 out:
--- a/include/block/block.h
+++ b/include/block/block.h
@ -242,8 +242,6 @@ int bdrv_pwrite_sync(BlockDriverState *bs, int64_t offset,
    const void *buf, int count);
 int coroutine_fn bdrv_co_readv(BlockDriverState *bs, int64_t sector_num,
    int nb_sectors, QEMUIOVector *qiov);
-int coroutine_fn bdrv_co_readv_no_serialising(BlockDriverState *bs,
-    int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
 int coroutine_fn bdrv_co_writev(BlockDriverState *bs, int64_t sector_num,
    int nb_sectors, QEMUIOVector *qiov);
 /*
--- a/1
+++ b/1
@ -72,7 +72,6 @@ bdrv_aio_readv(void *bs, int64_t sector_num, int nb_sectors, void *opaque) "bs %
 bdrv_aio_writev(void *bs, int64_t sector_num, int nb_sectors, void *opaque) "bs %p sector_num %"PRId64" nb_sectors %d opaque %p"
 bdrv_aio_write_zeroes(void *bs, int64_t sector_num, int nb_sectors, int flags, void *opaque) "bs %p sector_num %"PRId64" nb_sectors %d flags %#x opaque %p"
 bdrv_co_readv(void *bs, int64_t sector_num, int nb_sector) "bs %p sector_num %"PRId64" nb_sectors %d"
-bdrv_co_readv_no_serialising(void *bs, int64_t sector_num, int nb_sector) "bs %p sector_num %"PRId64" nb_sectors %d"
 bdrv_co_writev(void *bs, int64_t sector_num, int nb_sector) "bs %p sector_num %"PRId64" nb_sectors %d"
 bdrv_co_write_zeroes(void *bs, int64_t sector_num, int nb_sector, int flags) "bs %p sector_num %"PRId64" nb_sectors %d flags %#x"
 bdrv_co_do_copy_on_readv(void *bs, int64_t sector_num, int nb_sectors, int64_t cluster_sector_num, int cluster_nb_sectors) "bs %p sector_num %"PRId64" nb_sectors %d cluster_sector_num %"PRId64" cluster_nb_sectors %d"