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 DDA5226A08F; Mon, 23 Mar 2026 14:53:59 +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=1774277639; cv=none; b=r611zkq23B3czKCdYxggvjWu6jxLHqxrILrxx2wiCchfx9tLD4cm0krc1CagZ97oO9RltBa+5iMA6UyChhzsT0StzLbDXzLibT5yGK6JrJpYJdfWnqNmiPDt9zD3sqxgw8BWqft35Cp9Z624Qxwaw4S+C8uqATFInv2d643UKtI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774277639; c=relaxed/simple; bh=WHviqgNfywEja6Wns09EL9cbUreoUb2YrTJ5LPx8xs4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Rg4KUzmSVDo5NmhA0CkjimOOdfCuMHubCljjTH2nuaVgFAc7TIjBEQ5FdMWd06cchhx9Er1LFjj4mzHzgG6cFHgmsQ2nLitC4ZQUnXJRPS2yY6hh8GZoyiy2Lvz2gVMCyVlxh76qfdvGWPQ1NJN1u7xOtvczPP9nBCuIuulgwio= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=o4IrH4d5; 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="o4IrH4d5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 63545C4CEF7; Mon, 23 Mar 2026 14:53:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1774277639; bh=WHviqgNfywEja6Wns09EL9cbUreoUb2YrTJ5LPx8xs4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=o4IrH4d55/EB2ttQZP94VBKYIaxv8Af3p2lD9OYQqvxBju/f/HGiI3EScEe/lu7q6 dhFEHHAgGWlu8MIEheIzD0VSR/wZLs88eAeI/supow/RhcNFTfmu1n3o0t47zzJ47d Ao32SAokv0l0PPlW7X8ZyQhKI6GKhfTR5gCfEauA= 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 6.6 057/567] ext4: drop extent cache after doing PARTIAL_VALID1 zeroout Date: Mon, 23 Mar 2026 14:39:37 +0100 Message-ID: <20260323134535.226250944@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260323134533.749096647@linuxfoundation.org> References: <20260323134533.749096647@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 6.6-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 ed63260d792b1..2818d297ce464 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -3302,8 +3302,16 @@ 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