From: Thomas Lamprecht <t.lamprecht@proxmox.com>
To: Proxmox Backup Server development discussion
<pbs-devel@lists.proxmox.com>,
Stefan Reiter <s.reiter@proxmox.com>,
Dietmar Maurer <dietmar@proxmox.com>
Subject: Re: [pbs-devel] [PATCH v3 proxmox-backup 2/2] client: implement map/unmap commands for .img backups
Date: Thu, 1 Oct 2020 17:36:39 +0200 [thread overview]
Message-ID: <de93b7ad-0b35-4134-250b-f56d5b4861e1@proxmox.com> (raw)
In-Reply-To: <20200825114625.26527-2-s.reiter@proxmox.com>
On 25.08.20 13:46, Stefan Reiter wrote:
> Allows mapping fixed-index .img files (usually from VM backups) to be
> mapped to a local loopback device.
>
> The architecture uses a FUSE-backed temp file mapped to a loopdev:
>
> /dev/loopX -> FUSE /run/pbs-loopdev/xxx -> backup client -> PBS
>
> Since unmapping requires some cleanup (unmap the loopdev, stop FUSE,
> remove the temp files) a special 'unmap' command is added, which uses a
> PID file to send SIGINT to the backup-client instance started with
> 'map', which will handle the cleanup itself.
>
> The polling with select! in mount.rs needs to be split in two, since we
> have a chicken and egg problem between running FUSE and setting up the
> loop device - so we need to do them concurrently, until the loopdev is
> assigned, at which point we can report success and daemonize, and then
> continue polling the FUSE loop future.
>
> A loopdev module is added to tools containing all required functions for
> mapping a loop device to the FUSE file, with the ioctls moved into an
> inline module to avoid exposing them directly.
>
> The client code is placed in the 'mount' module, which, while
> admittedly a loose fit, allows reuse of the daemonizing code.
>
> Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
> ---
>
> v3:
> * better error messages in 'unmap'
> * rebase
>
> I checked, and FUSE is not notified when the loop device disconnects... I'd say
> we just have the user handle that.
>
>
> src/bin/proxmox-backup-client.rs | 2 +
> src/bin/proxmox_backup_client/mount.rs | 182 ++++++++++++++---
> src/tools.rs | 2 +
> src/tools/fuse_loop.rs | 258 +++++++++++++++++++++++++
> src/tools/loopdev.rs | 93 +++++++++
> 5 files changed, 509 insertions(+), 28 deletions(-)
> create mode 100644 src/tools/fuse_loop.rs
> create mode 100644 src/tools/loopdev.rs
>
What's the state of this? IIRC, Dietmar you wanted to give this a look?
Would be nice to have, IMO :-)
prev parent reply other threads:[~2020-10-01 15:36 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-25 11:46 [pbs-devel] [PATCH v3 proxmox-backup 1/2] client: mount: handle SIGTERM as well Stefan Reiter
2020-08-25 11:46 ` [pbs-devel] [PATCH v3 proxmox-backup 2/2] client: implement map/unmap commands for .img backups Stefan Reiter
2020-10-01 15:36 ` Thomas Lamprecht [this message]
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