Re: [RFC v3 10/11] btrfs: check for leaks of ordered stripes on umount

[Josef Bacik <josef@toxicpanda.com>]

On Mon, Oct 17, 2022 at 04:55:28AM -0700, Johannes Thumshirn wrote:
> Check if we're leaking any ordered stripes when unmounting a filesystem
> with an stripe tree.
> 
> This check is gated behind CONFIG_BTRFS_DEBUG to not affect any production
> type systems.
> 
> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
> ---
>  fs/btrfs/disk-io.c          |  2 ++
>  fs/btrfs/raid-stripe-tree.c | 29 +++++++++++++++++++++++++++++
>  fs/btrfs/raid-stripe-tree.h |  1 +
>  3 files changed, 32 insertions(+)
> 
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index 190caabf5fb7..e479e9829c3e 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -43,6 +43,7 @@
>  #include "space-info.h"
>  #include "zoned.h"
>  #include "subpage.h"
> +#include "raid-stripe-tree.h"
>  
>  #define BTRFS_SUPER_FLAG_SUPP	(BTRFS_HEADER_FLAG_WRITTEN |\
>  				 BTRFS_HEADER_FLAG_RELOC |\
> @@ -1480,6 +1481,7 @@ void btrfs_free_fs_info(struct btrfs_fs_info *fs_info)
>  	btrfs_put_root(fs_info->stripe_root);
>  	btrfs_check_leaked_roots(fs_info);
>  	btrfs_extent_buffer_leak_debug_check(fs_info);
> +	btrfs_check_ordered_stripe_leak(fs_info);
>  	kfree(fs_info->super_copy);
>  	kfree(fs_info->super_for_commit);
>  	kfree(fs_info->subpage_info);
> diff --git a/fs/btrfs/raid-stripe-tree.c b/fs/btrfs/raid-stripe-tree.c
> index 91e67600e01a..9a913c4cd44e 100644
> --- a/fs/btrfs/raid-stripe-tree.c
> +++ b/fs/btrfs/raid-stripe-tree.c
> @@ -30,6 +30,35 @@ static int ordered_stripe_less(struct rb_node *rba, const struct rb_node *rbb)
>  	return ordered_stripe_cmp(&stripe->logical, rbb);
>  }
>  
> +void btrfs_check_ordered_stripe_leak(struct btrfs_fs_info *fs_info)
> +{
> +#ifdef CONFIG_BTRFS_DEBUG
> +	struct rb_node *node;
> +
> +	if (!fs_info->stripe_root ||
> +	    RB_EMPTY_ROOT(&fs_info->stripe_update_tree))
> +		return;
> +
> +	mutex_lock(&fs_info->stripe_update_lock);
> +	while ((node = rb_first_postorder(&fs_info->stripe_update_tree))
> +	       != NULL) {
> +		struct btrfs_ordered_stripe *stripe =
> +			rb_entry(node, struct btrfs_ordered_stripe, rb_node);
> +

Can we get a WARN_ON_ONCE() in here?  That way xfstests failures will get
noticed as we'll get the dmesg failures.  Thanks,

Josef