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[209.85.167.177]) by smtp.gmail.com with ESMTPSA id r15sm1384307oot.5.2020.06.06.08.52.13 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 06 Jun 2020 08:52:13 -0700 (PDT) Received: by mail-oi1-f177.google.com with SMTP id j189so11099588oih.10 for ; Sat, 06 Jun 2020 08:52:13 -0700 (PDT) X-Received: by 2002:aca:c6ca:: with SMTP id w193mr5537850oif.81.1591458733028; Sat, 06 Jun 2020 08:52:13 -0700 (PDT) MIME-Version: 1.0 References: <202006051612.055GCL11009491@repo.freebsd.org> In-Reply-To: Reply-To: cem@freebsd.org From: Conrad Meyer Date: Sat, 6 Jun 2020 08:52:01 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: HEADSUP: GEOM label may be broken [Was Re: svn commit: r361838 - in head/sys/geom: . label] To: Xin LI Cc: freebsd-current Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 49fPCh0SBwz4CfM X-Spamd-Bar: -- Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=pass (mx1.freebsd.org: domain of csecem@gmail.com designates 209.85.210.44 as permitted sender) smtp.mailfrom=csecem@gmail.com X-Spamd-Result: default: False [-2.26 / 15.00]; HAS_REPLYTO(0.00)[cem@freebsd.org]; RCVD_VIA_SMTP_AUTH(0.00)[]; RWL_MAILSPIKE_GOOD(0.00)[209.85.210.44:from]; R_SPF_ALLOW(-0.20)[+ip4:209.85.128.0/17:c]; REPLYTO_ADDR_EQ_FROM(0.00)[]; RCVD_COUNT_THREE(0.00)[4]; TO_DN_ALL(0.00)[]; NEURAL_HAM_SHORT(-0.26)[-0.265]; RCPT_COUNT_TWO(0.00)[2]; FORGED_SENDER(0.30)[cem@freebsd.org,csecem@gmail.com]; MIME_TRACE(0.00)[0:+]; FREEMAIL_ENVFROM(0.00)[gmail.com]; ASN(0.00)[asn:15169, ipnet:209.85.128.0/17, country:US]; R_DKIM_NA(0.00)[]; TAGGED_FROM(0.00)[]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.01)[-1.009]; FROM_NEQ_ENVFROM(0.00)[cem@freebsd.org,csecem@gmail.com]; FROM_HAS_DN(0.00)[]; NEURAL_HAM_LONG(-0.99)[-0.985]; MIME_GOOD(-0.10)[text/plain]; PREVIOUSLY_DELIVERED(0.00)[freebsd-current@freebsd.org]; DMARC_NA(0.00)[freebsd.org]; TO_MATCH_ENVRCPT_SOME(0.00)[]; RCVD_IN_DNSWL_NONE(0.00)[209.85.210.44:from]; RCVD_TLS_ALL(0.00)[] X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 06 Jun 2020 15:52:17 -0000 Hi Xin Li, Thank you for the report and diagnosis. Sorry for the breakage. I have reverted the change and hope to address the issues you have identified. There seem to be two issues identified: 1. When ZFS attaches to a partition of a disk, the /dev/diskid label disappears. 2. geli(8) attach of symlink labels doesn't work (1) is interesting, as it does not seem to happen to UFS or swap consumers: # mount /dev/gpt/rootfs on / (ufs, local, noatime, soft-updates) # swapctl -l Device: 1024-blocks Used: /dev/vtbd0p2 1048576 0 # ls -l /dev/diskid/DISK-BHYVE-2613-8EFD-BAF4 /dev/gpt/{rootfs,swapfs} lrwxr-xr-x 1 root wheel 8 May 22 20:18 /dev/diskid/DISK-BHYVE-2613-8EFD-BAF4 -> ../vtbd0 lrwxr-xr-x 1 root wheel 10 May 22 20:18 /dev/gpt/rootfs -> ../vtbd0p3 lrwxr-xr-x 1 root wheel 10 May 22 20:18 /dev/gpt/swapfs -> ../vtbd0p2 I wonder what is different in the ZFS case here. (2) # ls -l /dev/gpt/testingeli lrwxr-xr-x 1 root wheel 8 Jun 6 08:33 /dev/gpt/testingeli -> ../md0s1 # geli init /dev/gpt/testingeli Enter new passphrase: Reenter new passphrase: ... # geli attach /dev/gpt/testingeli Enter passphrase: geli: Provider gpt/testingeli is invalid. geli: There was an error with at least one provider. So at least the latter problem is straightforward to resolve. I have a patch I'm testing locally now, and will upload to phabricator shortly. Best regards, Conrad On Sat, Jun 6, 2020 at 1:17 AM Xin Li wrote: > > I just spent quite some time to revive my laptop. TL;DR: if you are > using /dev/diskid or /dev/gptid labels and GELI, please wait until > things settled. > > === > > On 6/5/20 9:12 AM, Conrad Meyer wrote: > > Author: cem > > Date: Fri Jun 5 16:12:21 2020 > > New Revision: 361838 > > URL: https://svnweb.freebsd.org/changeset/base/361838 > > > > Log: > > geom_label: Use provider aliasing to alias upstream geoms > > > > For synthetic aliases (just pseudonyms inferred from metadata like GPT or > > UFS labels, GPT UUIDs, etc), use the GEOM provider aliasing system to create > > a symlink to the real device instead of creating an independent device. > > This makes it more clear which labels and devices correspond, and we can > > safely have multiple labels to a single device accessed at once. > > > > The confusingly named geom_label on-disk construct continues to behave > > identically to how it did before. > > > > This requires teaching GEOM's provider aliasing about the possibility > > that aliases might be added later in time, and GEOM's devfs interaction > > layer not to worry about existing aliases during retaste. > > > > Discussed with: imp > > Relnotes: sure, if we don't end up reverting it > > This would break (and the effect can be quite persistent and hard to > repair, see explanation below) existing configuration as some GEOM > classes are not converted to support the new way of device > representation, so I'd like to request this change be reverted for now > until these are fixed. > > Consider the following configuration, where one have a hard drive > partitioned with GPT, like: > > => 40 1953525088 ada1 GPT (932G) > 40 262144 1 efi (128M) > 262184 8388608 2 freebsd-zfs (4.0G) > 8650792 67108864 3 freebsd-swap (32G) > 75759656 1877765472 4 freebsd-zfs (895G) > > Now, the first ZFS pool is created as root pool. ZFS gets an exclusive > hold of 'ada1p2' despite the pool is carefully created to use > /dev/diskid/p2 instead of ada1p2. > > ZFS writes the new device path to vdev label. For ZFS, this doesn't > matter much as it always checks the label. > > However, this will prevent GEOM from properly creating > /dev/diskid/. > > In order to prevent accidentally writing data to wrong disk, for "raw" > disk partitions it's usually a good idea to reference them with labels, > either by /dev/diskid or /dev/gptid. With /dev/ada1p2 exclusively > accessed by ZFS, the /dev/diskid/ representing the disk is > now gone. > > And to make the situation even worse, simply changing the partition > reference to the corresponding /dev/gptid/ doesn't really work > either, when one is encrypting partitions individually. In the example > above, adap4 is an encrypted partition and with the alias change, one > can no longer "geli attach" them via /dev/gptid/. They can still > be attached by the "canonical" path (/dev/ada1p4), but for the swap > partition that would completely defeat the purpose of using label (to > prevent accidentally writing to the wrong disk). > > For my case, reverting to an older kernel is not sufficient to fix the > configuration, because ZFS is recording the "canonical" device path > (/dev/ada1p2) and /dev/diskid label for this disk disappeared somewhat > permanently (I would have to find a USB drive somewhere to fix the root > pool to use the "right" device path). > > > Differential Revision: https://reviews.freebsd.org/D24968 > [...] > > Modified: head/sys/geom/label/g_label.c > > ============================================================================== > > --- head/sys/geom/label/g_label.c Fri Jun 5 16:05:09 2020 (r361837) > > +++ head/sys/geom/label/g_label.c Fri Jun 5 16:12:21 2020 (r361838) > > @@ -344,18 +345,16 @@ g_label_taste(struct g_class *mp, struct g_provider *p > > { > > struct g_label_metadata md; > > struct g_consumer *cp; > > + struct g_class *clsp; > > struct g_geom *gp; > > int i; > > + bool changed; > > > > g_trace(G_T_TOPOLOGY, "%s(%s, %s)", __func__, mp->name, pp->name); > > g_topology_assert(); > > > > G_LABEL_DEBUG(2, "Tasting %s.", pp->name); > > > > - /* Skip providers that are already open for writing. */ > > - if (pp->acw > 0) > > - return (NULL); > > - > > if (strcmp(pp->geom->class->name, mp->name) == 0) > > return (NULL); > > > > @@ -391,9 +390,16 @@ g_label_taste(struct g_class *mp, struct g_provider *p > > if (md.md_provsize != pp->mediasize) > > break; > > > > + /* Skip providers that are already open for writing. */ > > + if (pp->acw > 0) { > > + g_access(cp, -1, 0, 0); > > + goto end; > > + } > > + > > (Is this still necessary when the eventual provider would be the real one?) > > I think symlink aliasing is a the right direction but we need to be > really careful to not break existing and legitimate usage. Since this > also breaks GELI when using with labels, I'd like to request that this > change be backed out for now until the consumers are correctly fixed. > > Cheers, >