[pbs-devel] [PATCH proxmox-backup v3 0/5] refactor datastore locking to use tmpfs

[Stefan Sterz <s.sterz@proxmox.com>]

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. The second
commit fixes a bug in the `BackupGroup`'s `relative_group_path()`
method. It would return the full path instead of a path relative to a
datastore. This is necessary because commit three uses this method to
generate lock file names. It also adds double stat'ing
and lock files under '/run' for each group/snapshot.

The fourth commit refactors locking for manifests and brings it
in-line with the group/snapshot locks. Finally the fifth commit fixes
a race condition when changing the owner of a datastore.

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

Stefan Sterz (5):
  fix #3935: datastore/api/backup: add lock helpers to backup dir/group
  fix: datastore: make relative_group_path() return relative path
  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                |   7 ++
 pbs-datastore/src/backup_info.rs     | 153 ++++++++++++++++++++++-----
 pbs-datastore/src/datastore.rs       |  68 ++++--------
 pbs-datastore/src/snapshot_reader.rs |  23 ++--
 src/api2/admin/datastore.rs          |   9 +-
 src/api2/backup/environment.rs       |   5 +-
 src/api2/backup/mod.rs               |   8 +-
 src/api2/reader/mod.rs               |   7 +-
 src/backup/verify.rs                 |  11 +-
 9 files changed, 189 insertions(+), 102 deletions(-)

-- 
2.30.2