From nobody Tue Feb 10 05:44:34 2026 Received: from dggsgout12.his.huawei.com (dggsgout12.his.huawei.com [45.249.212.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 66F462517AA; Sat, 25 Oct 2025 03:30:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.56 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761363014; cv=none; b=Vh051i/Hu3mMujOT0NtRURNntiUU64W5WoR1ekiAbyMbe7pCbVYyhseIAoo3cBymnJhlpOKPiIl5StVYjuwEYu5WZeNOMllwd6S8o4rDuwJii3b1BlQ6WQpUNwZAw5/KGVRo5nZkgpRLQahckgCWHrB6WEdCA/Do2G2VKF/2M2M= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761363014; c=relaxed/simple; bh=FmVUn3+xEVIo1jPDBKJqn+eT2s2jLQkSeEAUP66Zy80=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=VjON14I9FBX4KdzdqRDLALqzbjTYfMppS5H9DGs/Odv4S12xSl0eA0hqmIxggwX1y+qYw/CmSszSvhs4GVbGix0Vtuze3CnWOsMQnsygw0CTsLqCrbDKN8tsVi4aOzW02qBVHa6pCWW5D/nvOdHsBFX1gg1Ao2zJdeL2x2k2lyg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.216]) by dggsgout12.his.huawei.com (SkyGuard) with ESMTPS id 4ctlcT2qr3zKHMQT; Sat, 25 Oct 2025 11:29:13 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.75]) by mail.maildlp.com (Postfix) with ESMTP id 1C8D11A1B52; Sat, 25 Oct 2025 11:30:05 +0800 (CST) Received: from huaweicloud.com (unknown [10.50.87.129]) by APP2 (Coremail) with SMTP id Syh0CgBHnEQ6RPxox1YbBg--.45388S26; Sat, 25 Oct 2025 11:30:04 +0800 (CST) From: libaokun@huaweicloud.com To: linux-ext4@vger.kernel.org Cc: tytso@mit.edu, adilger.kernel@dilger.ca, jack@suse.cz, linux-kernel@vger.kernel.org, kernel@pankajraghav.com, mcgrof@kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, yi.zhang@huawei.com, yangerkun@huawei.com, chengzhihao1@huawei.com, libaokun1@huawei.com, libaokun@huaweicloud.com Subject: [PATCH 22/25] fs/buffer: prevent WARN_ON in __alloc_pages_slowpath() when BS > PS Date: Sat, 25 Oct 2025 11:22:18 +0800 Message-Id: <20251025032221.2905818-23-libaokun@huaweicloud.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20251025032221.2905818-1-libaokun@huaweicloud.com> References: <20251025032221.2905818-1-libaokun@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: Syh0CgBHnEQ6RPxox1YbBg--.45388S26 X-Coremail-Antispam: 1UD129KBjvJXoWxJrykCF4kCr4rKry7uryUZFb_yoW8uF15pF 4rKanxtrWkKF429Fy3AanxtFy3Kas5JayUCFWxW3s3Z3WDGF9I9rnrC3WUZF1rtFyxAFy0 qF45ArWUuF17trUanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUQa14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_JF0E3s1l82xGYI kIc2x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2 z4x0Y4vE2Ix0cI8IcVAFwI0_tr0E3s1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F 4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oVCq 3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7 IYx2IY67AKxVWUXVWUAwAv7VC2z280aVAFwI0_Gr1j6F4UJwAm72CE4IkC6x0Yz7v_Jr0_ Gr1lF7xvr2IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7M4IIrI8v6xkF7I0E8c xan2IY04v7M4kE6xkIj40Ew7xC0wCY1x0262kKe7AKxVWUtVW8ZwCF04k20xvY0x0EwIxG rwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E7480Y4 vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2Ij64vIr41lIxAIcVC0I7IY x2IY67AKxVW5JVW7JwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F4UJwCI42IY6xAIw2 0EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Gr0_Cr1lIxAIcVC2z280aVCY1x02 67AKxVW8Jr0_Cr1UYxBIdaVFxhVjvjDU0xZFpf9x0JUdsqAUUUUU= X-CM-SenderInfo: 5olet0hnxqqx5xdzvxpfor3voofrz/1tbiAQAMBWj7UbRJIgAAsV Content-Type: text/plain; charset="utf-8" From: Baokun Li In __alloc_pages_slowpath(), allocating page units greater than order-1 with the __GFP_NOFAIL flag may trigger an unexpected WARN_ON. To avoid this, handle the case separately in grow_dev_folio(). This ensures that buffer_head-based filesystems will not encounter the warning when using __GFP_NOFAIL to read metadata after BS > PS support is enabled. Signed-off-by: Baokun Li Reviewed-by: Zhang Yi --- fs/buffer.c | 33 +++++++++++++++++++++++++++++++-- 1 file changed, 31 insertions(+), 2 deletions(-) diff --git a/fs/buffer.c b/fs/buffer.c index 6a8752f7bbed..2f5a7dd199b2 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -1031,6 +1031,35 @@ static sector_t folio_init_buffers(struct folio *fol= io, return end_block; } =20 +static struct folio *blkdev_get_folio(struct address_space *mapping, + pgoff_t index, fgf_t fgp_flags, gfp_t gfp) +{ + struct folio *folio; + unsigned int min_order =3D mapping_min_folio_order(mapping); + + /* + * Allocating page units greater than order-1 with __GFP_NOFAIL in + * __alloc_pages_slowpath() can trigger an unexpected WARN_ON. + * Handle this case separately to suppress the warning. + */ + if (min_order <=3D 1) + return __filemap_get_folio(mapping, index, fgp_flags, gfp); + + while (1) { + folio =3D __filemap_get_folio(mapping, index, fgp_flags, + gfp & ~__GFP_NOFAIL); + if (!IS_ERR(folio) || !(gfp & __GFP_NOFAIL)) + return folio; + + if (PTR_ERR(folio) !=3D -ENOMEM && PTR_ERR(folio) !=3D -EAGAIN) + return folio; + + memalloc_retry_wait(gfp); + } + + return folio; +} + /* * Create the page-cache folio that contains the requested block. * @@ -1047,8 +1076,8 @@ static bool grow_dev_folio(struct block_device *bdev,= sector_t block, struct buffer_head *bh; sector_t end_block =3D 0; =20 - folio =3D __filemap_get_folio(mapping, index, - FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp); + folio =3D blkdev_get_folio(mapping, index, + FGP_LOCK | FGP_ACCESSED | FGP_CREAT, gfp); if (IS_ERR(folio)) return false; =20 --=20 2.46.1