When the root drive is also listed in EXTRA_FILESYSTEMS, its key is
taken before addPartitionRootFs runs. Returning false there sent the
agent to addLastResortRootFs, which picks the most active device and
could register a different drive as root, overwriting that drive's
extra entry. addPartitionRootFs has already resolved the root device,
so promote the existing entry to root instead.
addPartitionRootFs reported success even when addFsStat skipped the
registration because the I/O key was already in use, e.g. when the root
drive is also listed in EXTRA_FILESYSTEMS. hasRoot was then set without
any root filesystem, and the last-resort fallback never ran. addFsStat
now reports whether it registered the filesystem and addPartitionRootFs
propagates that.
Also uppercase the drive letter in windowsVolumeName so "c:" and "C:"
normalize to the same key.
filepath.Base is platform-dependent for a bare volume name: on Windows it
strips the "C:" specifier and returns "\", so every drive letter
normalizes to the same key. findIoDevice's exact match then returns
whichever disk.IOCounters entry the map yielded first, which registers the
root filesystem under a random drive. With EXTRA_FILESYSTEMS=D:,P: the
root disk disappears from the hub, and without it the root can be
registered under another drive's I/O device.
Normalize a bare volume specifier before taking a path base, and stop
taking a path base of the device in addPartitionRootFs, where it mangled
the value before findIoDevice could see it. registerFilesystemStats
already avoided this by only taking a base when the agent is not on
Windows.
Fixes#2417
- Match FILESYSTEM directly against I/O devices if partition lookup
fails
- Fall back to the most active I/O device if no root device is detected
- Add WARN logs in final fallback case to most active device
findIoDevice now normalizes device names and falls back to prefix-based
matching when partition names differ from IOCounter names (e.g. nda0p2 →
nda0 on FreeBSD). The most-active prefix-related device is selected,
avoiding the broad "most active of all" heuristic that caused Docker
misattribution in #1737.
- Stop using max-read fallback when mapping root filesystem to
diskstats.
- Keep root usage reporting even when root I/O cannot be mapped.
- Expand docker fallback mount detection to include /etc/resolv.conf and
/etc/hostname (in addition to /etc/hosts).
- Add clearer warnings when root block device detection is uncertain.
