From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oa1-f45.google.com (mail-oa1-f45.google.com [209.85.160.45]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4C3A02E282B for ; Mon, 12 Jan 2026 15:40:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.45 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768232445; cv=none; b=aTNVwaR/FuMhWvamdR41dl/KmNLCwBXsxdcjQLVXA/gMTTXtqT3Y5861L0GNSMUQYP+Ux5D3AUtGDsojS+bkUGnArF5fb2ViFM4SqOYFwrtXHY8UOaP+xsAc7f/k8gLM3e1WWi/dXSst9hRGhs3cwOmgW+cn/pQajnECzUj1y9Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768232445; c=relaxed/simple; bh=KXDBNYPs6o6+d58AfV6DwmytZgbc95aSZNdy7bL0lhc=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=jO91jXH9n3TeJX9n2vZp70t/UuV4JYJFhIvSbfc+tRCMGNP28UecWIGytns0wZMIFN4VBCWA7Ol5tWapWyp8VTmHTHAZc0/3DbfmnxrKEuQNPdSOCVxkPT06gOYh8+Vs7aJPAU9bA546b3ZTh9HbulmkpWYUJ7ipIHYnDk6nhe0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=Jb9ZozaZ; arc=none smtp.client-ip=209.85.160.45 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Jb9ZozaZ" Received: by mail-oa1-f45.google.com with SMTP id 586e51a60fabf-3e89d226c3aso6300876fac.2 for ; Mon, 12 Jan 2026 07:40:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1768232443; x=1768837243; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=yE1TQIm91uYk1rly71VaN4veqRSHPeBF3rZ1SklWl0A=; b=Jb9ZozaZy8nW96ga9P3GRK8Ubi3hkicFeyaSDhn2QsB31S2QbrkAC7jRHyDiQsB41a sQj2oZYmHoI6b5LvCRbEqC0D+i5CD/GujrMbLH1aZ7e8FOHkxgQUCNbFel/MpbXR/NM0 BzGwJh2zZFQhXjf8gWFuj+mvLCyV86gtkSQFMc1mTpH2WEaav4hHDFdV8PyE8PwER+LM /EmxJ7YOIT/MLfPc9QNvRumsBPW/J/J4+wkTp1B3zdl1dU5zOa1RJ8u1RZHei6xC6//O pyxy5T1LJdiXSgt4xD0vHP0wWp/6Zv+FqBYEWiNs71ggUl4qMcZ1G3lfObQtV/iYBgUB ALkw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1768232443; x=1768837243; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=yE1TQIm91uYk1rly71VaN4veqRSHPeBF3rZ1SklWl0A=; b=sxYgf8bGmAY8Hx5NNG9sK0kkumP9PrgoT+rH6+zCXc3fFgBSXwn91Sy7RnntPPTcVh zNkInc5gQIsSFDdSAZadJBu7fkiYZt11Y2g8Q4i3yCQP6MrqsS+ScmunFhhJPCYE4qV/ jAe7PnoGc7RX1JtS+sY5GfRzR4O7+6VtdGtvUkkSmOMfwWcADSqHzzSSnV2V+Z3vseju zquv6eGFIf+LgPxXqKTvMeok5fum3cz0jLvspQXLt2iV0NAayCe+pgk8z6nbcgQhZAqn ukvZVU3hGPfSD/omWsoHMaoiUqBq82bGilS/pfMdcoztJXCYXfb0CYHrQ1hbo4stV7z8 mkYw== X-Forwarded-Encrypted: i=1; AJvYcCURxlB5cOyD1Zfpc/ZEAb3umX/rKgyAAmWg8Ksrai2QA8Cuoq8oX7bfMQ2hNEMr3OMovpckgdg9dRgqEA==@vger.kernel.org X-Gm-Message-State: AOJu0YxKNJ7v2YmiBK3GiQSkPBm5s4NTo7+glj55EIofOiKg4eFZAawx fFN4dmx3mFcG1mhO0hg21PDX7dKz4ijsfY2WdrzURdbuuk+w4yQZGZxE X-Gm-Gg: AY/fxX6HJIWaAbIDqWnddxym0SzmhttAATmpnSNQXw87BdjBjDtKjkkk+A2TlsR3dc9 XU+pg4qRF6mk2uK2IpK4ycX5x+gE2t2YGrTbILFWT53vmdcFYoLh9q19yA77SmRH7KKzArvPNXC tJJvsjTU7e4RJIbPHTNSoEmifm7t95Q68M4Lzj3rtpGzb5EYQCwxWb83QUi5RhqWz+4a9y2cN8J NPenkiWeu3Sbvtqco2mwEqxLtIYI3Nfygs0a3OqSTIwiu/GcGeHDw5fnWp8Qwn/X2IZqg6z9/qL Qa0LK58aftX/e8EJlHuH2DfbVZyDwphkW8XnXMnCa3V9J69L+JbR5bCcspmfSpvkT/l3xz9hb1K 4tUO6ZlrOzYQhkHfHYpLMMC9zfO/VVywXDlHualVwxZ40THGV3vBZKSzoQ3zTxc+aAWbA+2UjaP j7fyp1jh0zz6Z8Y4C2I3QpK6dC8BoZVgep0PVAufDen48= X-Google-Smtp-Source: AGHT+IE3iTYZiF9/gdz5+xlFIrbcHiCazX2ptLJ7lv/yoamUJcApstAyZmEQ2vt6NrrX7xjd0X4+nw== X-Received: by 2002:a05:6820:4702:b0:65c:fe8b:53b9 with SMTP id 006d021491bc7-65f54f5e824mr6754811eaf.44.1768232443208; Mon, 12 Jan 2026 07:40:43 -0800 (PST) Received: from newman.cs.purdue.edu ([128.10.127.250]) by smtp.gmail.com with ESMTPSA id 586e51a60fabf-3ffa516150fsm12207861fac.20.2026.01.12.07.40.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 12 Jan 2026 07:40:42 -0800 (PST) From: Jiasheng Jiang To: Chris Mason , David Sterba , linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Jiasheng Jiang Subject: [PATCH] btrfs: zoned: remove redundant space_info lock and variable in do_allocation_zoned Date: Mon, 12 Jan 2026 15:40:40 +0000 Message-Id: <20260112154040.35746-1-jiashengjiangcool@gmail.com> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit In do_allocation_zoned, the code acquires space_info->lock followed by block_group->lock. However, the critical section does not access or modify any members of the space_info structure, making the lock acquisition and the space_info local variable redundant. This unnecessary locking also creates a potential circular wait deadlock (AB-BA) risk. Other paths, such as background reclaim or space reporting, could acquire block_group->lock and subsequently attempt to acquire space_info->lock to update global counters. This behavior diverges from other Zoned-specific paths like __btrfs_add_free_space_zoned which only rely on block_group->lock. Removing the acquisition of space_info->lock and its corresponding definition in do_allocation_zoned eliminates the deadlock risk and improves concurrency by reducing contention on the global space_info lock. Signed-off-by: Jiasheng Jiang --- fs/btrfs/extent-tree.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index e4cae34620d1..43d78056c274 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -3839,7 +3839,6 @@ static int do_allocation_zoned(struct btrfs_block_group *block_group, struct btrfs_block_group **bg_ret) { struct btrfs_fs_info *fs_info = block_group->fs_info; - struct btrfs_space_info *space_info = block_group->space_info; struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; u64 start = block_group->start; u64 num_bytes = ffe_ctl->num_bytes; @@ -3900,7 +3899,6 @@ static int do_allocation_zoned(struct btrfs_block_group *block_group, */ } - spin_lock(&space_info->lock); spin_lock(&block_group->lock); spin_lock(&fs_info->treelog_bg_lock); spin_lock(&fs_info->relocation_bg_lock); @@ -4002,7 +4000,6 @@ static int do_allocation_zoned(struct btrfs_block_group *block_group, spin_unlock(&fs_info->relocation_bg_lock); spin_unlock(&fs_info->treelog_bg_lock); spin_unlock(&block_group->lock); - spin_unlock(&space_info->lock); return ret; } -- 2.25.1