Re: [PATCH] xfs: scrub: unlock dquot before early return in quota scrub

[Darrick J. Wong]

On Thu, Mar 12, 2026 at 08:10:26PM +0800, hongao wrote:
> xchk_quota_item can return early after calling xchk_fblock_process_error.
> When that helper returns false, the function returned immediately without
> dropping dq->q_qlock, which can leave the dquot lock held and risk lock
> leaks or deadlocks in later quota operations.
> 
> Fix this by unlocking dq->q_qlock before the early return.
> 
> Signed-off-by: hongao <hongao@xxxxxxxxxxxxx>

Yep, that's a bug.

Cc: <stable@xxxxxxxxxxxxxxx> # v6.8
Fixes: 7d1f0e167a067e ("xfs: check the ondisk space mapping behind a dquot")
Reviewed-by: "Darrick J. Wong" <djwong@xxxxxxxxxx>

--D

> diff --git a/fs/xfs/scrub/quota.c b/fs/xfs/scrub/quota.c
> index 1d25bd5b892e..222812fe202c 100644
> --- a/fs/xfs/scrub/quota.c
> +++ b/fs/xfs/scrub/quota.c
> @@ -171,8 +171,10 @@ xchk_quota_item(
>  
>  	error = xchk_quota_item_bmap(sc, dq, offset);
>  	xchk_iunlock(sc, XFS_ILOCK_SHARED);
> -	if (!xchk_fblock_process_error(sc, XFS_DATA_FORK, offset, &error))
> +	if (!xchk_fblock_process_error(sc, XFS_DATA_FORK, offset, &error)) {
> +		mutex_unlock(&dq->q_qlock);
>  		return error;
> +	}
>  
>  	/*
>  	 * Warn if the hard limits are larger than the fs.
> -- 
> 2.51.0
> 
>