FAILED: patch "[PATCH] btrfs: zoned: clear data relocation bg on zone finish" failed to apply to 5.15-stable tree

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 5911f5382022aff2b817cb88f276756af229664d Mon Sep 17 00:00:00 2001
From: Johannes Thumshirn <[email protected]>
Date: Thu, 2 Dec 2021 00:47:14 -0800
Subject: [PATCH] btrfs: zoned: clear data relocation bg on zone finish

When finishing a zone that is used by a dedicated data relocation block group, also remove its reference from fs_info, so we're not trying to use a full block group for allocations during data relocation, which will always fail.

The result is we're not making any forward progress and end up in a deadlock situation.

index 67d932d70798..678a29469511 100644
@@ -1860,6 +1860,7 @@ int btrfs_zone_finish(struct btrfs_block_group *block_group)
 	block_group->alloc_offset = block_group->zone_capacity;
 	block_group->free_space_ctl->free_space = 0;
 	btrfs_clear_treelog_bg(block_group);
+	btrfs_clear_data_reloc_bg(block_group);
 	spin_unlock(&block_group->lock);
 
 	ret = blkdev_zone_mgmt(device->bdev, REQ_OP_ZONE_FINISH,

@@ -1942,6 +1943,7 @@ void btrfs_zone_finish_endio(struct btrfs_fs_info *fs_info, u64 logical, u64 len
 	ASSERT(block_group->alloc_offset == block_group->zone_capacity);
 	ASSERT(block_group->free_space_ctl->free_space == 0);
 	btrfs_clear_treelog_bg(block_group);
+	btrfs_clear_data_reloc_bg(block_group);
 	spin_unlock(&block_group->lock);
 
 	map = block_group->physical_map;

Hi Greg,

this patch doesn't need any backporting to stable. The failure can only happen on v5.16-rcX.

Thanks,
Johannes

Really? The Fixes: tag says otherwise:

as that commit id is in 5.15.4.

Perhaps that tag is incorrect?

thanks,

greg k-h

Nope, but 5.15.4 does not contain the functions where we forgot to add the calls to btrfs_clear_data_reloc_bg().

The bug was a race between me and Naohiro working on c2707a255623 and afba2bc036b0e ("btrfs: zoned: implement active zone tracking").

Thanks,
Johannes