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 1229419754E; Thu, 6 Jun 2024 14:21:59 +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=1717683719; cv=none; b=KKD//8S4Z6dOm34w1i6Q96stc+3s0SnIlSMYJrY9iYDLZps2RjtzyH0H/VRkEP1GGZCcps3yWwLvbEtI+4VO5Vys9H1E4B7NdAuxQbnBT/eFKLcKnsH6rOn7bavgj9zpZ/4OrmnEAu8fWa5tvF68XNmW+Myzu9H3nYPO5yWwdzE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717683719; c=relaxed/simple; bh=LKnffkIVAGBlbUt/YZm1L2+JaBVA3raQLY0ZLbWUCok=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=rJ7B4NZGEtiozktqOcrJ0C8X+fKxq5CNyFrNRZY7zDgiwxUqKheW9yuumEzgndvrET8gIDL0jpzSjDqY7cnkrWT81HmM3SLXSO6/xdtqYM8HFW5/1fV3bRlRJBnS+HzqaLQ2lJvBIn41fwhX+H6Wj5WsW7MGkO6GXHlmKkibyO0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=NDyx5kwT; 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="NDyx5kwT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E637DC2BD10; Thu, 6 Jun 2024 14:21:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1717683719; bh=LKnffkIVAGBlbUt/YZm1L2+JaBVA3raQLY0ZLbWUCok=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NDyx5kwTQtEA6gfPm5R/etlUq309z3g9F0pVIbXRI0DvqFHt40QHII+rAqWzRnDTy xzSoWURsSo23GiLVwq7Ec+oEtQ8NN37Iy5DnVYpPIHQhHvGRfuzjQphlGU1uq9vI3q 28kr9DI1yXMCOh1c/4FKKVCnDZDXmaJrxtQ0DA0E= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ryusuke Konishi , Bart Van Assche , Jens Axboe , kernel test robot , Andrew Morton , Sasha Levin Subject: [PATCH 6.6 617/744] nilfs2: make superblock data array index computation sparse friendly Date: Thu, 6 Jun 2024 16:04:49 +0200 Message-ID: <20240606131752.295435490@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240606131732.440653204@linuxfoundation.org> References: <20240606131732.440653204@linuxfoundation.org> User-Agent: quilt/0.67 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: Ryusuke Konishi [ Upstream commit 91d743a9c8299de1fc1b47428d8bb4c85face00f ] Upon running sparse, "warning: dubious: x & !y" is output at an array index calculation within nilfs_load_super_block(). The calculation is not wrong, but to eliminate the sparse warning, replace it with an equivalent calculation. Also, add a comment to make it easier to understand what the unintuitive array index calculation is doing and whether it's correct. Link: https://lkml.kernel.org/r/20240430080019.4242-3-konishi.ryusuke@gmail.com Fixes: e339ad31f599 ("nilfs2: introduce secondary super block") Signed-off-by: Ryusuke Konishi Cc: Bart Van Assche Cc: Jens Axboe Cc: kernel test robot Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin --- fs/nilfs2/the_nilfs.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c index 71400496ed365..3e3c1d32da180 100644 --- a/fs/nilfs2/the_nilfs.c +++ b/fs/nilfs2/the_nilfs.c @@ -592,7 +592,7 @@ static int nilfs_load_super_block(struct the_nilfs *nilfs, struct nilfs_super_block **sbp = nilfs->ns_sbp; struct buffer_head **sbh = nilfs->ns_sbh; u64 sb2off, devsize = bdev_nr_bytes(nilfs->ns_bdev); - int valid[2], swp = 0; + int valid[2], swp = 0, older; if (devsize < NILFS_SEG_MIN_BLOCKS * NILFS_MIN_BLOCK_SIZE + 4096) { nilfs_err(sb, "device size too small"); @@ -648,9 +648,25 @@ static int nilfs_load_super_block(struct the_nilfs *nilfs, if (swp) nilfs_swap_super_block(nilfs); + /* + * Calculate the array index of the older superblock data. + * If one has been dropped, set index 0 pointing to the remaining one, + * otherwise set index 1 pointing to the old one (including if both + * are the same). + * + * Divided case valid[0] valid[1] swp -> older + * ------------------------------------------------------------- + * Both SBs are invalid 0 0 N/A (Error) + * SB1 is invalid 0 1 1 0 + * SB2 is invalid 1 0 0 0 + * SB2 is newer 1 1 1 0 + * SB2 is older or the same 1 1 0 1 + */ + older = valid[1] ^ swp; + nilfs->ns_sbwcount = 0; nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime); - nilfs->ns_prot_seq = le64_to_cpu(sbp[valid[1] & !swp]->s_last_seq); + nilfs->ns_prot_seq = le64_to_cpu(sbp[older]->s_last_seq); *sbpp = sbp[0]; return 0; } -- 2.43.0