From: Shannon Sterz <s.sterz@proxmox.com>
To: pbs-devel@lists.proxmox.com
Subject: [pbs-devel] [PATCH proxmox-backup 0/4] refactor datastore locking to use tmpfs
Date: Mon, 10 Mar 2025 15:36:03 +0100 [thread overview]
Message-ID: <20250310143607.298339-1-s.sterz@proxmox.com> (raw)
The goal of this series is to make it safer to remove backup groups &
snapshots by separating the corresponding directories from their lock
files. By moving the lock files to the tmpfs-backed '/run' directory,
we also make sure that the lock files get cleaned up when the system
reboots.
This series refactors the locking mechanism inside the `DataStore`,
`BackupDir` and `BackupGroup` traits. In a first step locking methods
are added and the existing code is refactored to use them. Commit two
derives a lock file name under '/run' for each group/snapshot. It also
adds double stat'ing.
The third commit refactors locking for manifests and brings it in-line
with the group/snapshot locks. Finally, the last commit fixes a race
condition when changing the owner of a datastore.
This version is based on a fairly old series from 2022 [1]. As
discussed a bit on list already, we will need to make sure that this
series is applied in a way that doesn't allow for old and new versions
of the locking mechanism to be used in parallel [2].
[1]: https://lore.proxmox.com/pbs-devel/20220824124829.392189-1-s.sterz@proxmox.com/
[2]: https://lore.proxmox.com/pbs-devel/yqgs32dkpyexsxkezl3vy3tdc2jzfccfrh4h73ticcofjsptn7@npdp2ev2w3ro/T/#t
----
changes from v5:
* re-phrase commit messages to make it clear which commit actually
fixes the issue and what the commit implies in-terms of semantic
changes for error messages (thanks @ Thomas Lamprecht)
* make it so the series applies cleanly again and clean up a newly
added usage of `lock_dir_noblock`
changes from v4 (thanks @ Wolfgang Bumiller):
* stop using `to_string_lossy()`
* switch funtion signature of `create_locked_backup_group()` and
`create_locked_backup_dir` to use the `Arc` version of a datastore.
* smaller clippy fixes
* rebased on current master
changes from v3:
* moved patch 2 to the front so it can be applied separatelly more
easily
* rebased on current master
changes from v2:
* different encoding scheme for lock file names
* refactored locking methods to be used by the new BackupDir and
BackupGroup traits
* adapted lock file names to include namespaces
changes from v1 (thanks @ Wolfgang Bumiller & Thomas Lamprecht):
* split adding locking helpers and move '/run' into two commits
* instead of stat'ing the path of lock file twice, only use the file
descriptor for one of the stat'ing procedures instead
* several improvements to helper functions and documentation
Shannon Sterz (4):
datastore/api/backup: prepare for fix of #3935 by adding lock helpers
fix #3935: datastore/api/backup: move datastore locking to '/run'
fix #3935: datastore: move manifest locking to new locking method
fix: api: avoid race condition in set_backup_owner
pbs-config/src/lib.rs | 13 +-
pbs-datastore/Cargo.toml | 1 +
pbs-datastore/src/backup_info.rs | 177 +++++++++++++++++++++++----
pbs-datastore/src/datastore.rs | 70 ++++-------
pbs-datastore/src/snapshot_reader.rs | 20 ++-
src/api2/admin/datastore.rs | 9 +-
src/api2/backup/environment.rs | 14 +--
src/api2/backup/mod.rs | 8 +-
src/api2/reader/mod.rs | 7 +-
src/backup/verify.rs | 12 +-
src/server/sync.rs | 10 +-
11 files changed, 225 insertions(+), 116 deletions(-)
--
2.39.5
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next reply other threads:[~2025-03-10 14:36 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-10 14:36 Shannon Sterz [this message]
2025-03-10 14:36 ` [pbs-devel] [PATCH proxmox-backup 1/4] datastore/api/backup: prepare for fix of #3935 by adding lock helpers Shannon Sterz
2025-03-10 14:36 ` [pbs-devel] [PATCH proxmox-backup 2/4] fix #3935: datastore/api/backup: move datastore locking to '/run' Shannon Sterz
2025-03-10 14:36 ` [pbs-devel] [PATCH proxmox-backup 3/4] fix #3935: datastore: move manifest locking to new locking method Shannon Sterz
2025-03-10 14:36 ` [pbs-devel] [PATCH proxmox-backup 4/4] fix: api: avoid race condition in set_backup_owner Shannon Sterz
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