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

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

[gregkh]

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 <stable@vger.kernel.org>.

thanks,

greg k-h

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

From 5911f5382022aff2b817cb88f276756af229664d Mon Sep 17 00:00:00 2001
From: Johannes Thumshirn <johannes.thumshirn@wdc.com>
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.

Fixes: c2707a255623 ("btrfs: zoned: add a dedicated data relocation block group")
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 67d932d70798..678a29469511 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -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;

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

[Johannes Thumshirn]

On 12/12/2021 15:21, gregkh@linuxfoundation.org wrote:
> 
> 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 <stable@vger.kernel.org>.
> 

Hi Greg, 

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

Thanks,
	Johannes

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

[gregkh]

On Mon, Dec 13, 2021 at 07:34:37AM +0000, Johannes Thumshirn wrote:
> On 12/12/2021 15:21, gregkh@linuxfoundation.org wrote:
> > 
> > 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 <stable@vger.kernel.org>.
> > 
> 
> Hi Greg, 
> 
> this patch doesn't need any backporting to stable. The failure can only 
> happen on v5.16-rcX.

Really?  The Fixes: tag says otherwise:
	Fixes: c2707a255623 ("btrfs: zoned: add a dedicated data relocation block group")
as that commit id is in 5.15.4.

Perhaps that tag is incorrect?

thanks,

greg k-h

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

[Johannes Thumshirn]

On 13/12/2021 09:22, gregkh@linuxfoundation.org wrote:
> On Mon, Dec 13, 2021 at 07:34:37AM +0000, Johannes Thumshirn wrote:
>> On 12/12/2021 15:21, gregkh@linuxfoundation.org wrote:
>>>
>>> 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 <stable@vger.kernel.org>.
>>>
>>
>> Hi Greg, 
>>
>> this patch doesn't need any backporting to stable. The failure can only 
>> happen on v5.16-rcX.
> 
> Really?  The Fixes: tag says otherwise:
> 	Fixes: c2707a255623 ("btrfs: zoned: add a dedicated data relocation block group")
> as that commit id is in 5.15.4.
> 
> Perhaps that tag is incorrect?
> 

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