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 8938A264614; Mon, 23 Mar 2026 15:24:48 +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=1774279488; cv=none; b=vB5zzR7ZvzgLynVrizblle0xC7zwhGhrkwyKdVlLEww+qFgUA2VbDxXUhsp+vq+fabVYmVnaIH89VQFuFdE2Q8EHEiDOYd/ngtojKA7JR5x7N+E1/ZsJOJvcYc4BBGC4FPYGO2XHGgByNDnbQjXCLQW4jwMTMh28CQcZdSb6eLc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774279488; c=relaxed/simple; bh=l+I4VArnQuqguy+cutWvUiGjupPOs+MzJT4NykF8XiE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CjwOlK/VWwc1JnEKzOcXONoL2skxIOvWB5xr3lC5K53awKaem9hRYcaOYM0myDHKA0gio8C6d5d+UST5SxN5885LWaCYIDtDaeHU3xbNkLgzYXpA/pU8Vu771RDW1OCp5Z9tgxN/vAY1ZKP2tup1QVNw39aH7oKTrUVDyl1/55o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=vt2r+fHX; 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="vt2r+fHX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0DD1FC4CEF7; Mon, 23 Mar 2026 15:24:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1774279488; bh=l+I4VArnQuqguy+cutWvUiGjupPOs+MzJT4NykF8XiE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vt2r+fHXIvTyoy3UjVlQgLOa/8t4lt9wfAwSUmF0UQ4pAkazqtc89UrpLr9VAQszM Zzbbxt9lDfA6yDSN5u129IgIj0x70Wa3zv9Nm2of8r8LujM65PshU54AUbYogX5Y1l hZAp5qJEZS4JrvqE/R8x7zx8wl0oiwfHSgOfdaOo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Zhang Yi , Ojaswin Mujoo , Baokun Li , stable@kernel.org, Theodore Tso , Sasha Levin Subject: [PATCH 6.1 045/481] ext4: dont zero the entire extent if EXT4_EXT_DATA_PARTIAL_VALID1 Date: Mon, 23 Mar 2026 14:40:27 +0100 Message-ID: <20260323134526.331931713@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 1bf6974822d1dba86cf11b5f05498581cf3488a2 ] 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 Signed-off-by: Sasha Levin --- fs/ext4/extents.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index e2f9c27c7e161..da7414e84ead8 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -3298,6 +3298,15 @@ 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); @@ -3373,7 +3382,9 @@ static int 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)) { -- 2.51.0