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 229814EFFC8; Tue, 13 Oct 2026 12:10:02 +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=1791893404; cv=none; b=LXfB1tIbPLobmT3hpZ3Zov9mnKDZvpHsPUz3HcPM0G2cD0OoM/qPJxxJd+gylHtyNNfc+dkOvKfgLWrC31kD2u3mrxrWsE3ozgTbXsUhZR3zoMiy1JLJp1yDoJZevgG1SLIeeHFwkk1ZMndXEaFN57LgHgL5I0erKweVkdnn8UQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791893404; c=relaxed/simple; bh=DUZ3eezX/ughiciQDT59DNjujMyKt74a+mOxrsRkZSM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=oc8ry0MEBaTgNyMGnUlK1fZI+OrJqjffXuJagaxPwCVQWN2tapyVNa+yoJmXTAaOUB83k/ggZHhKefNB5CmEe41pUufZOR710Vuir92AKI5T1ny1Cj/IyVhAxCdZ2Cb1DiJrK3fsmOE6UiiQgK3EjPk+xPdZwo9rQOkvNY+/7Uw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ZqORy/h1; 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="ZqORy/h1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 335F81F000FF; Tue, 13 Oct 2026 12:10:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1791893402; bh=CREgkV1J8Y2OSnh6W4uPDObveUjvivSn3kdaQ8q5kW8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ZqORy/h17+Y28Un79MzS5+V7bx4cf3YB80Z7tH0PHsWMQyrj7WOVnuF22EJPDQWy7 A+dAf7o8MZMejht6C/oZpiQ6lWgLImEngQzGKzM4mHNlZrjtvmu/uubwynIRDeEZX0 PlpHBTer7xN/pagizX+F2piG5Fm+jrVUU85khqck= 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 6.18 215/621] f2fs: fix data loss caused by incorrect use of nat_entry flag Date: Tue, 13 Oct 2026 13:33:30 +0200 Message-ID: <20261013112925.963383507@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261013112920.855194808@linuxfoundation.org> References: <20261013112920.855194808@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 6.18-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 823b78c4aa5b1..60969e5f1201b 100644 --- a/fs/f2fs/node.c +++ b/fs/f2fs/node.c @@ -428,6 +428,7 @@ 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, false); if (e && get_nat_flag(e, HAS_LAST_FSYNC) && @@ -435,6 +436,7 @@ 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