[PATCH proxmox-backup 0/4] fix 7642: s3: avoid expensive uid/gid lookups

[Christian Ebner <c.ebner@proxmox.com>]

As reported by a user in the community forum [0] and the thereof
resulting bugzilla entry [1], phase 2 of garbage collection currently
produces avoidable syscalls and parsing overhead, reading
/etc/nsswitch.conf and /etc/passwd for each per-chunk file locking
call. This is however not limited to garbage collection, but rather
affects per-chunk file locking in general. The backup_user() lookup
was identified as the culprit.

This patch series fixes the overhead by only reading the user once at
the start of garbage collection or whenever a s3 backend instance is
created (which already performs the user lookup anyways), storing it
for the rest of the backend lifetime.

[0] https://forum.proxmox.com/threads/s3-gc-phase-2-nsswitch-passwd-overhead.183709/
[1] https://bugzilla.proxmox.com/show_bug.cgi?id=7642

Christian Ebner (4):
  local datastore cache: combine same module use statements
  datastore/api: s3: wrap s3 client into s3 backend type
  datastore: s3: avoid double calls to rather expensive backup_user()
  fix #7642: s3: avoid repeated user lookup for per-chunk file locking

 pbs-config/src/lib.rs                         |  30 +-
 pbs-datastore/src/backup_info.rs              |  64 +++--
 pbs-datastore/src/chunk_store.rs              |  33 ++-
 pbs-datastore/src/datastore.rs                | 262 +++++++++++-------
 pbs-datastore/src/lib.rs                      |   2 +-
 pbs-datastore/src/local_chunk_reader.rs       |  19 +-
 .../src/local_datastore_lru_cache.rs          |  14 +-
 src/api2/config/datastore.rs                  |  62 ++---
 src/api2/reader/mod.rs                        |  13 +-
 src/backup/verify.rs                          |   4 +-
 src/server/pull.rs                            |  10 +-
 11 files changed, 304 insertions(+), 209 deletions(-)

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2.47.3