1 files changed, 18 insertions, 28 deletions

diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index a18e0e23f6a6..2544805544f0 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -2717,8 +2717,6 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx,
 		mutex_unlock(&fs_info->scrub_lock);
 		wake_up(&fs_info->scrub_pause_wait);
 
-		dev_replace->cursor_left = dev_replace->cursor_right;
-		dev_replace->item_needs_writeback = 1;
 		btrfs_put_block_group(cache);
 		if (ret)
 			break;
@@ -2732,6 +2730,9 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx,
 			break;
 		}
 
+		dev_replace->cursor_left = dev_replace->cursor_right;
+		dev_replace->item_needs_writeback = 1;
+
 		key.offset = found_key.offset + length;
 		btrfs_release_path(path);
 	}
@@ -2783,7 +2784,6 @@ static noinline_for_stack int scrub_workers_get(struct btrfs_fs_info *fs_info,
 {
 	int ret = 0;
 
-	mutex_lock(&fs_info->scrub_lock);
 	if (fs_info->scrub_workers_refcnt == 0) {
 		if (is_dev_replace)
 			btrfs_init_workers(&fs_info->scrub_workers, "scrub", 1,
@@ -2813,21 +2813,17 @@ static noinline_for_stack int scrub_workers_get(struct btrfs_fs_info *fs_info,
 	}
 	++fs_info->scrub_workers_refcnt;
 out:
-	mutex_unlock(&fs_info->scrub_lock);
-
 	return ret;
 }
 
 static noinline_for_stack void scrub_workers_put(struct btrfs_fs_info *fs_info)
 {
-	mutex_lock(&fs_info->scrub_lock);
 	if (--fs_info->scrub_workers_refcnt == 0) {
 		btrfs_stop_workers(&fs_info->scrub_workers);
 		btrfs_stop_workers(&fs_info->scrub_wr_completion_workers);
 		btrfs_stop_workers(&fs_info->scrub_nocow_workers);
 	}
 	WARN_ON(fs_info->scrub_workers_refcnt < 0);
-	mutex_unlock(&fs_info->scrub_lock);
 }
 
 int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
@@ -2888,23 +2884,18 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
 		return -EINVAL;
 	}
 
-	ret = scrub_workers_get(fs_info, is_dev_replace);
-	if (ret)
-		return ret;
 
 	mutex_lock(&fs_info->fs_devices->device_list_mutex);
 	dev = btrfs_find_device(fs_info, devid, NULL, NULL);
 	if (!dev || (dev->missing && !is_dev_replace)) {
 		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
-		scrub_workers_put(fs_info);
 		return -ENODEV;
 	}
-	mutex_lock(&fs_info->scrub_lock);
 
+	mutex_lock(&fs_info->scrub_lock);
 	if (!dev->in_fs_metadata || dev->is_tgtdev_for_dev_replace) {
 		mutex_unlock(&fs_info->scrub_lock);
 		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
-		scrub_workers_put(fs_info);
 		return -EIO;
 	}
 
@@ -2915,10 +2906,17 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
 		btrfs_dev_replace_unlock(&fs_info->dev_replace);
 		mutex_unlock(&fs_info->scrub_lock);
 		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
-		scrub_workers_put(fs_info);
 		return -EINPROGRESS;
 	}
 	btrfs_dev_replace_unlock(&fs_info->dev_replace);
+
+	ret = scrub_workers_get(fs_info, is_dev_replace);
+	if (ret) {
+		mutex_unlock(&fs_info->scrub_lock);
+		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
+		return ret;
+	}
+
 	sctx = scrub_setup_ctx(dev, is_dev_replace);
 	if (IS_ERR(sctx)) {
 		mutex_unlock(&fs_info->scrub_lock);
@@ -2931,13 +2929,15 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
 
 	atomic_inc(&fs_info->scrubs_running);
 	mutex_unlock(&fs_info->scrub_lock);
-	mutex_unlock(&fs_info->fs_devices->device_list_mutex);
 
 	if (!is_dev_replace) {
-		down_read(&fs_info->scrub_super_lock);
+		/*
+		 * by holding device list mutex, we can
+		 * kick off writing super in log tree sync.
+		 */
 		ret = scrub_supers(sctx, dev);
-		up_read(&fs_info->scrub_super_lock);
 	}
+	mutex_unlock(&fs_info->fs_devices->device_list_mutex);
 
 	if (!ret)
 		ret = scrub_enumerate_chunks(sctx, dev, start, end,
@@ -2954,10 +2954,10 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
 
 	mutex_lock(&fs_info->scrub_lock);
 	dev->scrub_device = NULL;
+	scrub_workers_put(fs_info);
 	mutex_unlock(&fs_info->scrub_lock);
 
 	scrub_free_ctx(sctx);
-	scrub_workers_put(fs_info);
 
 	return ret;
 }
@@ -2987,16 +2987,6 @@ void btrfs_scrub_continue(struct btrfs_root *root)
 	wake_up(&fs_info->scrub_pause_wait);
 }
 
-void btrfs_scrub_pause_super(struct btrfs_root *root)
-{
-	down_write(&root->fs_info->scrub_super_lock);
-}
-
-void btrfs_scrub_continue_super(struct btrfs_root *root)
-{
-	up_write(&root->fs_info->scrub_super_lock);
-}
-
 int btrfs_scrub_cancel(struct btrfs_fs_info *fs_info)
 {
 	mutex_lock(&fs_info->scrub_lock);