Merge PR #48732 into main

* refs/pull/48732/head:
	doc: add MDS treatise on segments
	pybind/mgr/dashboard: bump teuthology version
	qa/tasks/vstart_runner: stop overriding _run_python
	qa: stop overriding ceph_w prefix in vstart_runner
	qa/tasks/vstart_runner: update teuthology helper tool paths
	qa/tasks/vstart_runner: allow writing to command's stdin
	vstart.sh: always add CEPH_CONF to vstart_environment.sh
	qa: use stdin-killer for python3 command
	qa: add killpoint testing for mds shutdown
	qa: fix background exit condition
	qa: add filesystem helper for setting transient config
	qa: add helper for waiting for a rank to fail
	mds: add incompat feature for minor log segments
	mds: introduce ELid event to create/close log
	mds: change EResetJournal to major segment boundary
	mds: add killpoints for MDS shutdown
	qa: add numerous subtree test
	mds: track larger log events in perf dump
	mds: add minor LogSegment boundaries
	mds: obviate MDLog::start_entry
	mds: retype to properly sized unsigned ints
	mds: use unsigned type for event count
	mds: use base Context class for generalization
	mds: optimize segment lookup
	mds: add stream dump for LogSegment
	mds: handle conf changes in mdlog
	mds: remove redundant comment
	mds: remove unused method
	mds: set a reasonable minimum number of segments
	mds: sort configs

Reviewed-by: Venky Shankar <vshankar@redhat.com>