From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AF3C5C433F5 for ; Fri, 11 Feb 2022 22:28:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239069AbiBKW2S (ORCPT ); Fri, 11 Feb 2022 17:28:18 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:60626 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232917AbiBKW2Q (ORCPT ); Fri, 11 Feb 2022 17:28:16 -0500 Received: from out4-smtp.messagingengine.com (out4-smtp.messagingengine.com [66.111.4.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 21EE5D51 for ; Fri, 11 Feb 2022 14:28:13 -0800 (PST) Received: from compute3.internal (compute3.nyi.internal [10.202.2.43]) by mailout.nyi.internal (Postfix) with ESMTP id 49E245C01A0; Fri, 11 Feb 2022 17:28:12 -0500 (EST) Received: from mailfrontend2 ([10.202.2.163]) by compute3.internal (MEProxy); Fri, 11 Feb 2022 17:28:12 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bur.io; h=cc:cc :content-type:date:date:from:from:in-reply-to:in-reply-to :message-id:mime-version:references:reply-to:sender:subject :subject:to:to; s=fm3; bh=y7tvgdnPlFPloXX/T9v8234Xg569DOcd6+TxTy PCc4A=; b=UR7i+VTC76Ye1+W/S0C9TTf8Z+C7Ro+yQnzipMZmLnau5fyUsOYD4L Q8J/0qTT61I0vCeQn65G2d0dw+vuTL0+jdLuQVIn5GcJnf0P67hwm+YQezvZj5vG /l3eWVDj2oboAYfAE1s5zdOWSFoOAJvChA/JzhFog6wT22dC9iboAreCrR8AZPOb BEgFsiPMZwWWUxmyL48G184vSOFNixTIDOpzcW9CVwoZ5ZLHYK70jYztq7FfLPQr YbOsxWFCdK6ni5mvI3CwyQMqqd8FEtuuGTC2dfgVg1W//YP2ENpuyatduxk0dSix q7IEcQSXAJGZk3hkXB/1hScRgTKKhJCA== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:date:date:from:from :in-reply-to:in-reply-to:message-id:mime-version:references :reply-to:sender:subject:subject:to:to:x-me-proxy:x-me-proxy :x-me-sender:x-me-sender:x-sasl-enc; s=fm2; bh=y7tvgdnPlFPloXX/T 9v8234Xg569DOcd6+TxTyPCc4A=; b=Ulwgnlt4nWI59O6oVniPfh1WkKdhjpmDn wN1NpEcf2hq+IyTo/wPcemuy+h3xUYlzKJAO3Jopdp1wFodq60H4dp+TyBK8QqQT AnFTW2KXNf0IClRbnzDkAH22ap/uo3PjrSTdTEIuEelbKF20e4Xrf0Q2P7UkVoHJ C7OnHCgIkB5NhjH33jwdpxFpFjoepb6W0tRoTcVDsIN/kmkybbNrjKR6RW/Lieei 4Fu1CuUkTt3dkmPOWMHtNjMxIyeVP78vo9G82unmBE8zsgCUYm1KFJihsOSzRaJu Creg8jSnPGB753n7RtKfmjwQtZRMiwwr4y200+dXLLqDQyUgAZmrg== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvvddrieefgdduheekucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhepfffhvffukfhfgggtuggjsehttdertddttddvnecuhfhrohhmpeeuohhrihhs uceuuhhrkhhovhcuoegsohhrihhssegsuhhrrdhioheqnecuggftrfgrthhtvghrnhephe duveelkeeiteelveeiuefhudehtdeigfehkeeffeegledvueevgefgudeuveefnecuvehl uhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmrghilhhfrhhomhepsghorhhishessg hurhdrihho X-ME-Proxy: Received: by mail.messagingengine.com (Postfix) with ESMTPA; Fri, 11 Feb 2022 17:28:11 -0500 (EST) Date: Fri, 11 Feb 2022 14:28:10 -0800 From: Boris Burkov To: Josef Bacik Cc: linux-btrfs@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH 2/8] btrfs: handle csum lookup errors properly on reads Message-ID: References: <9aa5cdf08820eeb53feb0457bc6994231a7ff9fd.1644532798.git.josef@toxicpanda.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9aa5cdf08820eeb53feb0457bc6994231a7ff9fd.1644532798.git.josef@toxicpanda.com> Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Thu, Feb 10, 2022 at 05:44:20PM -0500, Josef Bacik wrote: > Currently any error we get while trying to lookup csums during reads > shows up as a missing csum, and then on the read completion side we spit > out an error saying there was a csum mismatch and we increase the device > corruption count. > > However we could have gotten an EIO from the lookup. We could also be > inside of a memory constrained container and gotten a ENOMEM while > trying to do the read. In either case we don't want to make this look > like a file system corruption problem, we want to make it look like the > actual error it is. Capture any negative value, convert it to the > appropriate blk_sts_t, free the csum array if we have one and bail. > > Signed-off-by: Josef Bacik > --- > fs/btrfs/file-item.c | 13 +++++++++++-- > 1 file changed, 11 insertions(+), 2 deletions(-) > > diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c > index efb24cc0b083..e68be492109d 100644 > --- a/fs/btrfs/file-item.c > +++ b/fs/btrfs/file-item.c > @@ -368,6 +368,7 @@ blk_status_t btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio, u8 *dst > { > struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); > struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; > + struct btrfs_bio *bbio = NULL; > struct btrfs_path *path; > const u32 sectorsize = fs_info->sectorsize; > const u32 csum_size = fs_info->csum_size; > @@ -377,6 +378,7 @@ blk_status_t btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio, u8 *dst > u8 *csum; > const unsigned int nblocks = orig_len >> fs_info->sectorsize_bits; > int count = 0; > + blk_status_t ret = BLK_STS_OK; > > if ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM) || > test_bit(BTRFS_FS_STATE_NO_CSUMS, &fs_info->fs_state)) > @@ -400,7 +402,7 @@ blk_status_t btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio, u8 *dst > return BLK_STS_RESOURCE; > > if (!dst) { > - struct btrfs_bio *bbio = btrfs_bio(bio); > + bbio = btrfs_bio(bio); > > if (nblocks * csum_size > BTRFS_BIO_INLINE_CSUM_SIZE) { > bbio->csum = kmalloc_array(nblocks, csum_size, GFP_NOFS); > @@ -456,6 +458,13 @@ blk_status_t btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio, u8 *dst > > count = search_csum_tree(fs_info, path, cur_disk_bytenr, > search_len, csum_dst); > + if (count < 0) { > + ret = errno_to_blk_status(count); > + if (bbio) > + btrfs_bio_free_csum(bbio); > + break; > + } > + > if (count <= 0) { This new error handling doesn't quite mesh with the existing logic, IMO. 1) count <= 0 is redundant with count < 0 above and it's confusing to think about whether this code runs for count < 0. 2) it really is not running the nodatacow thing for the reloc inodes for negative return values anymore. Is that desirable? I found the original commit about it: 'Btrfs: fix nodatasum handling in balancing code' and it looks like that one cared about the 0 case, not the negative case, but that's not what the logic or comment suggest as they are. I think if you switch it to explicitly: < 0 -> error; run the new bail code. == 0 -> not found; deal with reloc, warn otherwise. and make a single comment covering it, then it would make sense to me. > /* > * Either we hit a critical error or we didn't find > @@ -491,7 +500,7 @@ blk_status_t btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio, u8 *dst > } > > btrfs_free_path(path); > - return BLK_STS_OK; > + return ret; > } > > int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end, > -- > 2.26.3 >