From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 A3A6F9460; Sat, 17 Oct 2026 17:39:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792258745; cv=none; b=cJOThj85Y/it+xRKa9uO3c/kFvHvCMk00FIfhNju/PQPSjX0nJrTlndulSPPauxAh/LJD1l/libO7UbhU/p0juspFWDFothXaBe1/sz2PNOmgQxqaIhot++n1On9JbYYZO2+tqpPucdbS0FcgIFnfuX4OHURCVEIuPTWodBf7WU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792258745; c=relaxed/simple; bh=P4eFABvVNrvvMWUxtj7PuPFHG4NO2hV8tdT6n5K2r6M=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fldXOtIt0f6WRjIPouGyjwSF+PptW01uGtFkDaVtNYlie6WbkYhpePI8LKJThEQ4OXlbTevBRiY6Zhx7JieAB0FCYW4cykuBfIgJA2a1d3nD4WtsnWetiz1tB5cfxSjE3c5w8PIJBofTZ+yhGB2ig+5Ast506PNH54OeVdZKStg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=uNhc6ZNT; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="uNhc6ZNT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 05B221F000C4; Sat, 17 Oct 2026 17:39:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792258744; bh=qvtXe+UuGYr+ONaLgRuECrkDRYZKFZ2pSj0mM0kfSss=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=uNhc6ZNTgJ3zVfYe906xUBO0J0H1AHVC388mZo+f15UnG6wvtvnfNwJWADbnfReur KH5mtR+TtLgf/2YhuoRcUAAueryL0H59tH/ZzHOdKcy+guITcCAqr4yuPseelkhyVU JibRE86NRwnKKPDXpM6hJ4FryAyitsxpaSTXYMd0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yongpeng Yang , Chao Yu , Jaegeuk Kim , Sasha Levin Subject: [PATCH 6.6 0986/1674] f2fs: fix data loss caused by incorrect use of nat_entry flag Date: Sat, 17 Oct 2026 17:54:18 +0200 Message-ID: <20261017160456.430469064@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261017160431.119607952@linuxfoundation.org> References: <20261017160431.119607952@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev 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: Yongpeng Yang [ Upstream commit 238e14eb7226f883b72caccd2d37bf5707df066b ] Data loss can occur when fsync is performed on a newly created file (before any checkpoint has been written) concurrently with a checkpoint operation. The scenario is as follows: create & write & fsync 'file A' write checkpoint - f2fs_do_sync_file // inline inode - f2fs_write_inode // inode folio is dirty - f2fs_write_checkpoint - f2fs_flush_merged_writes - f2fs_sync_node_pages - f2fs_flush_nat_entries - f2fs_fsync_node_pages // no dirty node - f2fs_need_inode_block_update // return false SPO and lost 'file A' f2fs_flush_nat_entries() sets the IS_CHECKPOINTED and HAS_LAST_FSYNC flags for the nat_entry, but this does not mean that the checkpoint has actually completed successfully. However, f2fs_need_inode_block_update() checks these flags and incorrectly assumes that the checkpoint has finished. The root cause is that the semantics of IS_CHECKPOINTED and HAS_LAST_FSYNC are only guaranteed after the checkpoint write fully completes. This patch modifies f2fs_need_inode_block_update() to acquire the sbi->node_write lock before reading the nat_entry flags, ensuring that once IS_CHECKPOINTED and HAS_LAST_FSYNC are observed to be set, the checkpoint operation has already completed. Fixes: e05df3b115e7 ("f2fs: add node operations") Signed-off-by: Yongpeng Yang Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Sasha Levin --- fs/f2fs/node.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c index d9021bfee5cf0..c6da0daece881 100644 --- a/fs/f2fs/node.c +++ b/fs/f2fs/node.c @@ -419,6 +419,7 @@ bool f2fs_need_inode_block_update(struct f2fs_sb_info *sbi, nid_t ino) struct nat_entry *e; bool need_update = true; + f2fs_down_read(&sbi->node_write); f2fs_down_read(&nm_i->nat_tree_lock); e = __lookup_nat_cache(nm_i, ino); if (e && get_nat_flag(e, HAS_LAST_FSYNC) && @@ -426,6 +427,7 @@ bool f2fs_need_inode_block_update(struct f2fs_sb_info *sbi, nid_t ino) get_nat_flag(e, HAS_FSYNCED_INODE))) need_update = false; f2fs_up_read(&nm_i->nat_tree_lock); + f2fs_up_read(&sbi->node_write); return need_update; } -- 2.53.0