From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 4C5A912CDA5; Mon, 23 Mar 2026 16:09:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774282186; cv=none; b=Y0Cl8ukRjLcTptzlvsmwTUtuCpMn77cmqLUuONEh3AvZIY85dU19XlY+gi7ozXVXQcdsoEAiRbIj+o/tcX7Wjo0WZ9ETdXvY2LF6wmcr8596ofFbFcWlpA6tm42oIIgLLNbRa90hp4+EVLWXj4oMCGUDckOwHXYdOFibGZG5uNU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774282186; c=relaxed/simple; bh=H083cs6Hg0TFcfMw9pLQs+aMP4lJ0mUHiGe4ZKpxGn8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kxcJcSC5SIaMSDsvnv7s3JgNgHH0oX42CVEMr3OwDGEQG7xltQlg7350RktPSrHKg6dmZqQBSJxZxwPom6rZ7QotYmWyGvzMDM2I+9IsW386ZUlG61taD0XJv1pIctOByYpcGww/b2jau9m4zuY0yI1dfFlBKJ7M3B2gl8GAjic= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=CwK4w/w2; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="CwK4w/w2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 96BE7C4CEF7; Mon, 23 Mar 2026 16:09:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1774282185; bh=H083cs6Hg0TFcfMw9pLQs+aMP4lJ0mUHiGe4ZKpxGn8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CwK4w/w2/9CaDV+ZvrSjasYXAwv28MG3QynajNuLbiUR/Z0dA8WFA/4OhQOk5clJH 1/YsrDEqMUrcT+7sWkiinQsiHtwXylj04uNiA4VXi0gFyZuqODvwo8L9eiUmffgOK+ kQl1bOlZEgegd2VQN4BQc6YyR3Spbmv79pu3E5OU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Zhang Yi , Baokun Li , stable@kernel.org, Ojaswin Mujoo , Theodore Tso , Sasha Levin Subject: [PATCH 6.1 046/481] ext4: drop extent cache after doing PARTIAL_VALID1 zeroout Date: Mon, 23 Mar 2026 14:40:28 +0100 Message-ID: <20260323134526.353478867@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260323134525.256603107@linuxfoundation.org> References: <20260323134525.256603107@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zhang Yi [ Upstream commit 6d882ea3b0931b43530d44149b79fcd4ffc13030 ] When splitting an unwritten extent in the middle and converting it to initialized in ext4_split_extent() with the EXT4_EXT_MAY_ZEROOUT and EXT4_EXT_DATA_VALID2 flags set, it could leave a stale unwritten extent. Assume we have an unwritten file and buffered write in the middle of it without dioread_nolock enabled, it will allocate blocks as written extent. 0 A B N [UUUUUUUUUUUU] on-disk extent U: unwritten extent [UUUUUUUUUUUU] extent status tree [--DDDDDDDD--] D: valid data |<- ->| ----> this range needs to be initialized ext4_split_extent() first try to split this extent at B with EXT4_EXT_DATA_PARTIAL_VALID1 and EXT4_EXT_MAY_ZEROOUT flag set, but ext4_split_extent_at() failed to split this extent due to temporary lack of space. It zeroout B to N and leave the entire extent as unwritten. 0 A B N [UUUUUUUUUUUU] on-disk extent [UUUUUUUUUUUU] extent status tree [--DDDDDDDDZZ] Z: zeroed data ext4_split_extent() then try to split this extent at A with EXT4_EXT_DATA_VALID2 flag set. This time, it split successfully and leave an written extent from A to N. 0 A B N [UUWWWWWWWWWW] on-disk extent W: written extent [UUUUUUUUUUUU] extent status tree [--DDDDDDDDZZ] Finally ext4_map_create_blocks() only insert extent A to B to the extent status tree, and leave an stale unwritten extent in the status tree. 0 A B N [UUWWWWWWWWWW] on-disk extent W: written extent [UUWWWWWWWWUU] extent status tree [--DDDDDDDDZZ] Fix this issue by always cached extent status entry after zeroing out the second part. Signed-off-by: Zhang Yi Reviewed-by: Baokun Li Cc: stable@kernel.org Reviewed-by: Ojaswin Mujoo Message-ID: <20251129103247.686136-7-yi.zhang@huaweicloud.com> Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin --- fs/ext4/extents.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index da7414e84ead8..30b0b25aac9ff 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -3304,8 +3304,16 @@ static struct ext4_ext_path *ext4_split_extent_at(handle_t *handle, * extent length and ext4_split_extent() split will the * first half again. */ - if (split_flag & EXT4_EXT_DATA_PARTIAL_VALID1) + if (split_flag & EXT4_EXT_DATA_PARTIAL_VALID1) { + /* + * Drop extent cache to prevent stale unwritten + * extents remaining after zeroing out. + */ + ext4_es_remove_extent(inode, + le32_to_cpu(zero_ex.ee_block), + ext4_ext_get_actual_len(&zero_ex)); goto fix_extent_len; + } /* update the extent length and mark as initialized */ ex->ee_len = cpu_to_le16(ee_len); -- 2.51.0