btrfs: rename btrfs_device::scrub_device to scrub_ctx

btrfs_device::scrub_device is not a device which is being scrubbed,
but it holds the scrub context, so rename to reflect the same. No
functional changes here.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/scrub.c

@@ -4145,7 +4145,7 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
 	}
 
 	btrfs_dev_replace_lock(&fs_info->dev_replace, 0);
-	if (dev->scrub_device ||
+	if (dev->scrub_ctx ||
 	    (!is_dev_replace &&
 	     btrfs_dev_replace_is_ongoing(&fs_info->dev_replace))) {
 		btrfs_dev_replace_unlock(&fs_info->dev_replace, 0);
@@ -4170,7 +4170,7 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
 		return PTR_ERR(sctx);
 	}
 	sctx->readonly = readonly;
-	dev->scrub_device = sctx;
+	dev->scrub_ctx = sctx;
 	mutex_unlock(&fs_info->fs_devices->device_list_mutex);
 
 	/*
@@ -4205,7 +4205,7 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
 		memcpy(progress, &sctx->stat, sizeof(*progress));
 
 	mutex_lock(&fs_info->scrub_lock);
-	dev->scrub_device = NULL;
+	dev->scrub_ctx = NULL;
 	scrub_workers_put(fs_info);
 	mutex_unlock(&fs_info->scrub_lock);
 
@@ -4262,16 +4262,16 @@ int btrfs_scrub_cancel_dev(struct btrfs_fs_info *fs_info,
 	struct scrub_ctx *sctx;
 
 	mutex_lock(&fs_info->scrub_lock);
-	sctx = dev->scrub_device;
+	sctx = dev->scrub_ctx;
 	if (!sctx) {
 		mutex_unlock(&fs_info->scrub_lock);
 		return -ENOTCONN;
 	}
 	atomic_inc(&sctx->cancel_req);
-	while (dev->scrub_device) {
+	while (dev->scrub_ctx) {
 		mutex_unlock(&fs_info->scrub_lock);
 		wait_event(fs_info->scrub_pause_wait,
-			   dev->scrub_device == NULL);
+			   dev->scrub_ctx == NULL);
 		mutex_lock(&fs_info->scrub_lock);
 	}
 	mutex_unlock(&fs_info->scrub_lock);
@@ -4288,7 +4288,7 @@ int btrfs_scrub_progress(struct btrfs_fs_info *fs_info, u64 devid,
 	mutex_lock(&fs_info->fs_devices->device_list_mutex);
 	dev = btrfs_find_device(fs_info, devid, NULL, NULL);
 	if (dev)
-		sctx = dev->scrub_device;
+		sctx = dev->scrub_ctx;
 	if (sctx)
 		memcpy(progress, &sctx->stat, sizeof(*progress));
 	mutex_unlock(&fs_info->fs_devices->device_list_mutex);

fs/btrfs/volumes.h

@@ -131,7 +131,7 @@ struct btrfs_device {
 	struct completion flush_wait;
 
 	/* per-device scrub information */
-	struct scrub_ctx *scrub_device;
+	struct scrub_ctx *scrub_ctx;
 
 	struct btrfs_work work;
 	struct rcu_head rcu;