From mboxrd@z Thu Jan 1 00:00:00 1970
Return-Path: <pbs-devel-bounces@lists.proxmox.com>
Received: from firstgate.proxmox.com (firstgate.proxmox.com [IPv6:2a01:7e0:0:424::9])
by lore.proxmox.com (Postfix) with ESMTPS id D4AB920EC88
for <inbox@lore.proxmox.com>; Thu, 25 Apr 2024 08:05:55 +0200 (CEST)
Received: from firstgate.proxmox.com (localhost [127.0.0.1])
by firstgate.proxmox.com (Proxmox) with ESMTP id 54B8B1AA55;
Thu, 25 Apr 2024 08:06:01 +0200 (CEST)
Mime-Version: 1.0
Date: Thu, 25 Apr 2024 08:05:27 +0200
Message-Id: <D0SZ75BEC46E.3K3R0WTNWPV30@proxmox.com>
From: "Hannes Laimer" <h.laimer@proxmox.com>
To: "Wolfgang Bumiller" <w.bumiller@proxmox.com>
X-Mailer: aerc 0.17.0-78-g4ffbaa6b3946
References: <20240423083000.28002-1-h.laimer@proxmox.com>
<20240423083000.28002-7-h.laimer@proxmox.com>
<652skntahltrhvy7ftnqezkxjb2orfshcqtujfepkksf7e6cyd@cggigo56vaqq>
In-Reply-To: <652skntahltrhvy7ftnqezkxjb2orfshcqtujfepkksf7e6cyd@cggigo56vaqq>
X-SPAM-LEVEL: Spam detection results: 0
AWL 0.009 Adjusted score from AWL reputation of From: address
BAYES_00 -1.9 Bayes spam probability is 0 to 1%
DMARC_MISSING 0.1 Missing DMARC policy
KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment
SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record
SPF_PASS -0.001 SPF: sender matches SPF record
Subject: Re: [pbs-devel] [PATCH proxmox-backup v9 06/26] datastore: add
helper for checking if a removable datastore is available
X-BeenThere: pbs-devel@lists.proxmox.com
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Proxmox Backup Server development discussion
<pbs-devel.lists.proxmox.com>
List-Unsubscribe: <https://lists.proxmox.com/cgi-bin/mailman/options/pbs-devel>,
<mailto:pbs-devel-request@lists.proxmox.com?subject=unsubscribe>
List-Archive: <http://lists.proxmox.com/pipermail/pbs-devel/>
List-Post: <mailto:pbs-devel@lists.proxmox.com>
List-Help: <mailto:pbs-devel-request@lists.proxmox.com?subject=help>
List-Subscribe: <https://lists.proxmox.com/cgi-bin/mailman/listinfo/pbs-devel>,
<mailto:pbs-devel-request@lists.proxmox.com?subject=subscribe>
Reply-To: Proxmox Backup Server development discussion
<pbs-devel@lists.proxmox.com>
Cc: pbs-devel@lists.proxmox.com
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Errors-To: pbs-devel-bounces@lists.proxmox.com
Sender: "pbs-devel" <pbs-devel-bounces@lists.proxmox.com>
On Wed Apr 24, 2024 at 3:30 PM CEST, Wolfgang Bumiller wrote:
> On Tue, Apr 23, 2024 at 10:29:40AM +0200, Hannes Laimer wrote:
> > Signed-off-by: Hannes Laimer <h.laimer@proxmox.com>
> > ---
> > pbs-api-types/src/maintenance.rs | 2 +-
> > pbs-datastore/src/datastore.rs | 44 ++++++++++++++++++++++++++++++++
> > pbs-datastore/src/lib.rs | 2 +-
> > 3 files changed, 46 insertions(+), 2 deletions(-)
> >
> > diff --git a/pbs-api-types/src/maintenance.rs b/pbs-api-types/src/maintenance.rs
> > index fd4d3416..4f653ec7 100644
> > --- a/pbs-api-types/src/maintenance.rs
> > +++ b/pbs-api-types/src/maintenance.rs
> > @@ -81,7 +81,7 @@ impl MaintenanceMode {
> > /// Used for deciding whether the datastore is cleared from the internal cache after the last
> > /// task finishes, so all open files are closed.
> > pub fn is_offline(&self) -> bool {
> > - self.ty == MaintenanceType::Offline
> > + self.ty == MaintenanceType::Offline || self.ty == MaintenanceType::Unmount
> > }
> >
> > pub fn check(&self, operation: Option<Operation>) -> Result<(), Error> {
> > diff --git a/pbs-datastore/src/datastore.rs b/pbs-datastore/src/datastore.rs
> > index f9b986c1..978ebb70 100644
> > --- a/pbs-datastore/src/datastore.rs
> > +++ b/pbs-datastore/src/datastore.rs
> > @@ -14,6 +14,7 @@ use proxmox_schema::ApiType;
> > use proxmox_sys::error::SysError;
> > use proxmox_sys::fs::{file_read_optional_string, replace_file, CreateOptions};
> > use proxmox_sys::fs::{lock_dir_noblock, DirLockGuard};
> > +use proxmox_sys::linux::procfs::MountInfo;
> > use proxmox_sys::process_locker::ProcessLockSharedGuard;
> > use proxmox_sys::WorkerTaskContext;
> > use proxmox_sys::{task_log, task_warn};
> > @@ -49,6 +50,39 @@ pub fn check_backup_owner(owner: &Authid, auth_id: &Authid) -> Result<(), Error>
> > Ok(())
> > }
> >
> > +/// check if a removable datastore is currently available/mounted by using the UUID
> > +/// to find the `/dev/sdX` path and checking in /proc/self/mountinfo for entries containing it.
> > +/// If it should mounted, but not in the expected path, so config.path, it is considered not
> > +/// available.
> > +pub fn is_datastore_available(config: &DataStoreConfig) -> bool {
> > + config.backing_device.as_ref().map_or(true, |uuid| {
> > + if let Ok(store_dev_path) = std::fs::read_link(Path::new("/dev/disk/by-uuid").join(uuid))
> > + .map(|p| p.to_string_lossy().into_owned())
> > + .map(|p| p.replace("../..", "/dev"))
>
> ^ Merge the two .maps together and you can drop the into_owned()
>
> Also, this is very fragile!
> `/proc/self/mountinfo` does NOT necessarily contain the final device
> node.
> For instance, for LVs you do NOT see `/dev/dm-xy`, but
> `/dev/mapper/foo-bar`.
>
> I pushed an alternative to my `staff` repo's
> `removable-datastore-review` branch which worked for my testing.
>
> There I instead `stat` the backing device and the source device found in
> the MountInfo and compare their `st_rdev` values.
>
This is a very good idea, and does sound more robust. But I don't think
we actually want to mount LVMs as removable datastores.
> > + .map(PathBuf::from)
>
> ^ Not strictly needed
>
> > + {
> > + let store_mount_point = config.get_mount_point().map(|mp| PathBuf::from(&mp));
>
> ^ The loop below only ever returns true if this is Some, so we can leave
> early here if it is not.
>
> > +
> > + MountInfo::read().map_or(false, |mount_info| {
> > + mount_info
> > + .iter()
> > + .filter_map(|(_, entry)| {
> > + entry
> > + .mount_source
> > + .as_ref()
> > + .map(|source| (&entry.mount_point, source))
> > + })
> > + .any(|(mount_point, mount_source)| {
> > + Some(PathBuf::from(&mount_point)) == store_mount_point
> > + && PathBuf::from(&mount_source) == store_dev_path
>
> ^Note that you can always use `Path` instead of allocating PathBufs if
> all you want to do is comapre stuff.
>
> > + })
> > + })
> > + } else {
> > + false
> > + }
> > + })
> > +}
_______________________________________________
pbs-devel mailing list
pbs-devel@lists.proxmox.com
https://lists.proxmox.com/cgi-bin/mailman/listinfo/pbs-devel