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 9904F33B6F5 for ; Tue, 24 Feb 2026 21:43:48 +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=1771969428; cv=none; b=uFClwOIsyqQUMrBVZRuzeemDWLt+GxR0ZpoonfDREo317SsZTvulxck1j9KhWGaxvFAPDIO61ZyUxfmYtZUB8MnnHgjiWHHx8LauEHlAzbjVt5wN3D1bb81i7cvL9lobkXPUhDC0EITa5/IU0iNPRDNR3vnGSDRZlIcEV9QrYaM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771969428; c=relaxed/simple; bh=HTGc4p61J2kwVT6YeW5+8ddmVbW/AaryL6KKPumVeXU=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=KWxILTFhY8hxwuEKnmYl4K7bUON5Bdmn/5+BUBvr9Kb4Clbi8A/tusW+92q0Tm3sAcEpCeFGzCxsPZY5FOwVpJcxyH+Tkt5uLM5sp4Q8FpaA6ALvDQooLlWO44ooYUplc8lbh8lwCiUc+Fuvc7zgXFol6lk5qTTbaUM1CvXQUWQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=wL13tUSr; 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="wL13tUSr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4B1D5C116D0; Tue, 24 Feb 2026 21:43:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1771969428; bh=HTGc4p61J2kwVT6YeW5+8ddmVbW/AaryL6KKPumVeXU=; h=Subject:To:Cc:From:Date:From; b=wL13tUSrbdSGvA09X74aBlYqNVgi6vcI01vmQpxS0fSDDAOgviV+C8R2OCmHqTwsP mNQulW16W8BWd6vk/PrZmfGgz5qJ53PyrfdX3XLKXkuI8ftpP9va9dFoQRqR2ja9dG RXNbgJVkk4cgmS0DIcm3KLhB7r6rm/gA01zbFBC8= Subject: FAILED: patch "[PATCH] ext4: don't zero the entire extent if" failed to apply to 5.15-stable tree To: yi.zhang@huawei.com,libaokun1@huawei.com,ojaswin@linux.ibm.com,tytso@mit.edu Cc: From: Date: Tue, 24 Feb 2026 13:43:41 -0800 Message-ID: <2026022440-antihero-predator-93cb@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 1bf6974822d1dba86cf11b5f05498581cf3488a2 # git commit -s git send-email --to '' --in-reply-to '2026022440-antihero-predator-93cb@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 1bf6974822d1dba86cf11b5f05498581cf3488a2 Mon Sep 17 00:00:00 2001 From: Zhang Yi Date: Sat, 29 Nov 2025 18:32:34 +0800 Subject: [PATCH] ext4: don't zero the entire extent if EXT4_EXT_DATA_PARTIAL_VALID1 When allocating initialized blocks from a large unwritten extent, or when splitting an unwritten extent during end I/O and converting it to initialized, there is currently a potential issue of stale data if the extent needs to be split in the middle. 0 A B N [UUUUUUUUUUUU] U: unwritten extent [--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_ENTIRE_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 mark the entire extent from 0 to N as written. 0 A B N [WWWWWWWWWWWW] W: written extent [SSDDDDDDDDZZ] Z: zeroed, S: stale 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 left a stale written extent from 0 to A. 0 A B N [WW|WWWWWWWWWW] [SS|DDDDDDDDZZ] Fix this by pass EXT4_EXT_DATA_PARTIAL_VALID1 to ext4_split_extent_at() when splitting at B, don't convert the entire extent to written and left it as unwritten after zeroing out B to N. The remaining work is just like the standard two-part split. ext4_split_extent() will pass the EXT4_EXT_DATA_VALID2 flag when it calls ext4_split_extent_at() for the second time, allowing it to properly handle the split. If the split is successful, it will keep extent from 0 to A as unwritten. Signed-off-by: Zhang Yi Reviewed-by: Ojaswin Mujoo Reviewed-by: Baokun Li Cc: stable@kernel.org Message-ID: <20251129103247.686136-3-yi.zhang@huaweicloud.com> Signed-off-by: Theodore Ts'o diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 8d5ca450aa5d..1fee84ea20af 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -3310,6 +3310,15 @@ static struct ext4_ext_path *ext4_split_extent_at(handle_t *handle, } if (!err) { + /* + * The first half contains partially valid data, the + * splitting of this extent has not been completed, fix + * extent length and ext4_split_extent() split will the + * first half again. + */ + if (split_flag & EXT4_EXT_DATA_PARTIAL_VALID1) + goto fix_extent_len; + /* update the extent length and mark as initialized */ ex->ee_len = cpu_to_le16(ee_len); ext4_ext_try_to_merge(handle, inode, path, ex); @@ -3379,7 +3388,9 @@ static struct ext4_ext_path *ext4_split_extent(handle_t *handle, split_flag1 |= EXT4_EXT_MARK_UNWRIT1 | EXT4_EXT_MARK_UNWRIT2; if (split_flag & EXT4_EXT_DATA_VALID2) - split_flag1 |= EXT4_EXT_DATA_ENTIRE_VALID1; + split_flag1 |= map->m_lblk > ee_block ? + EXT4_EXT_DATA_PARTIAL_VALID1 : + EXT4_EXT_DATA_ENTIRE_VALID1; path = ext4_split_extent_at(handle, inode, path, map->m_lblk + map->m_len, split_flag1, flags1); if (IS_ERR(path))