[PATCH] btrfs: hold space_info->lock when clearing periodic reclaim ready

[PATCH] btrfs: hold space_info->lock when clearing periodic reclaim ready

[Sun YangKai]

btrfs_set_periodic_reclaim_ready() requires space_info->lock to be held,
as enforced by lockdep_assert_held(). However, btrfs_reclaim_sweep() was
calling it after do_reclaim_sweep() returns, at which point
space_info->lock is no longer held.

Fix this by explicitly acquiring space_info->lock before clearing the
periodic reclaim ready flag in btrfs_reclaim_sweep().

Fixes: 19eff93dc738 ("btrfs: fix periodic reclaim condition")
Reported-by: Chris Mason <clm@meta.com>
Closes: https://lore.kernel.org/linux-btrfs/20260208182556.891815-1-clm@meta.com/
Signed-off-by: Sun YangKai <sunk67188@gmail.com>
---
 fs/btrfs/space-info.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c
index 1dd65fae6349..931f0dc02b95 100644
--- a/fs/btrfs/space-info.c
+++ b/fs/btrfs/space-info.c
@@ -2205,8 +2205,11 @@ void btrfs_reclaim_sweep(const struct btrfs_fs_info *fs_info)
 		if (!btrfs_should_periodic_reclaim(space_info))
 			continue;
 		for (raid = 0; raid < BTRFS_NR_RAID_TYPES; raid++) {
-			if (do_reclaim_sweep(space_info, raid))
+			if (do_reclaim_sweep(space_info, raid)) {
+				spin_lock(&space_info->lock);
 				btrfs_set_periodic_reclaim_ready(space_info, false);
+				spin_unlock(&space_info->lock);
+			}
 		}
 	}
 }
-- 
2.52.0

Re: [PATCH] btrfs: hold space_info->lock when clearing periodic reclaim ready

[Boris Burkov]

On Mon, Feb 09, 2026 at 08:53:39PM +0800, Sun YangKai wrote:
> btrfs_set_periodic_reclaim_ready() requires space_info->lock to be held,
> as enforced by lockdep_assert_held(). However, btrfs_reclaim_sweep() was
> calling it after do_reclaim_sweep() returns, at which point
> space_info->lock is no longer held.
> 
> Fix this by explicitly acquiring space_info->lock before clearing the
> periodic reclaim ready flag in btrfs_reclaim_sweep().
> 
> Fixes: 19eff93dc738 ("btrfs: fix periodic reclaim condition")
> Reported-by: Chris Mason <clm@meta.com>
> Closes: https://lore.kernel.org/linux-btrfs/20260208182556.891815-1-clm@meta.com/
> Signed-off-by: Sun YangKai <sunk67188@gmail.com>

Reviewed-by: Boris Burkov <boris@bur.io>

> ---
>  fs/btrfs/space-info.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c
> index 1dd65fae6349..931f0dc02b95 100644
> --- a/fs/btrfs/space-info.c
> +++ b/fs/btrfs/space-info.c
> @@ -2205,8 +2205,11 @@ void btrfs_reclaim_sweep(const struct btrfs_fs_info *fs_info)
>  		if (!btrfs_should_periodic_reclaim(space_info))
>  			continue;
>  		for (raid = 0; raid < BTRFS_NR_RAID_TYPES; raid++) {
> -			if (do_reclaim_sweep(space_info, raid))
> +			if (do_reclaim_sweep(space_info, raid)) {
> +				spin_lock(&space_info->lock);
>  				btrfs_set_periodic_reclaim_ready(space_info, false);
> +				spin_unlock(&space_info->lock);
> +			}
>  		}
>  	}
>  }
> -- 
> 2.52.0
> 

Re: [PATCH] btrfs: hold space_info->lock when clearing periodic reclaim ready

[David Sterba]

On Mon, Feb 09, 2026 at 08:53:39PM +0800, Sun YangKai wrote:
> btrfs_set_periodic_reclaim_ready() requires space_info->lock to be held,
> as enforced by lockdep_assert_held(). However, btrfs_reclaim_sweep() was
> calling it after do_reclaim_sweep() returns, at which point
> space_info->lock is no longer held.
> 
> Fix this by explicitly acquiring space_info->lock before clearing the
> periodic reclaim ready flag in btrfs_reclaim_sweep().
> 
> Fixes: 19eff93dc738 ("btrfs: fix periodic reclaim condition")
> Reported-by: Chris Mason <clm@meta.com>
> Closes: https://lore.kernel.org/linux-btrfs/20260208182556.891815-1-clm@meta.com/

Please use Link: for the original report unless the tag is known to be
used for some sort of automation, e.g. what syzbot does.

> Signed-off-by: Sun YangKai <sunk67188@gmail.com>

Added to for-next, thanks.

Re: [PATCH] btrfs: hold space_info->lock when clearing periodic reclaim ready

[Sun YangKai]

On 2026/2/25 01:06, David Sterba wrote:
> On Mon, Feb 09, 2026 at 08:53:39PM +0800, Sun YangKai wrote:
>> btrfs_set_periodic_reclaim_ready() requires space_info->lock to be held,
>> as enforced by lockdep_assert_held(). However, btrfs_reclaim_sweep() was
>> calling it after do_reclaim_sweep() returns, at which point
>> space_info->lock is no longer held.
>>
>> Fix this by explicitly acquiring space_info->lock before clearing the
>> periodic reclaim ready flag in btrfs_reclaim_sweep().
>>
>> Fixes: 19eff93dc738 ("btrfs: fix periodic reclaim condition")
>> Reported-by: Chris Mason <clm@meta.com>
>> Closes: https://lore.kernel.org/linux-btrfs/20260208182556.891815-1-clm@meta.com/
> 
> Please use Link: for the original report unless the tag is known to be
> used for some sort of automation, e.g. what syzbot does.

Got it. Thanks a lot :)
> 
>> Signed-off-by: Sun YangKai <sunk67188@gmail.com>
> 
> Added to for-next, thanks.