Re: disk revalidation updates and OOM

[Christoph Hellwig <hch@lst.de>]

On Mon, Mar 16, 2020 at 07:01:09PM +0800, He Zhe wrote:
> > Do 142fe8f and 979c690d work with the build fix applied? (f0b870d
> > shouldn't be interesting for this case).
> 
> Sorry for slow reply.
> 
> With my build fix applied, the issue is triggered since 142fe8f.
> And I can see the endless loop of invalidate and revalidate...

Thanks.  Can you test the patch below that restores the previous
rather odd behavior of not clearing the capacity to 0 if partition
scanning is not enabled?


diff --git a/fs/block_dev.c b/fs/block_dev.c
index 69bf2fb6f7cd..daac27f4b821 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1520,10 +1520,13 @@ int bdev_disk_changed(struct block_device *bdev, bool invalidate)
 	if (ret)
 		return ret;
 
-	if (invalidate)
-		set_capacity(disk, 0);
-	else if (disk->fops->revalidate_disk)
-		disk->fops->revalidate_disk(disk);
+	if (invalidate) {
+		if (disk_part_scan_enabled(disk))
+			set_capacity(disk, 0);
+	} else {
+		if (disk->fops->revalidate_disk)
+			disk->fops->revalidate_disk(disk);
+	}
 
 	check_disk_size_change(disk, bdev, !invalidate);