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William Gill d68cd6c0e8 v1.30-notify-1: rebase patch series onto scoutfs v1.30

Upstream released v1.30 (ad65116 on 2026-04-16 per the scoutfs tag).
The CI's daily cron picked the new tag and failed because our patch
series targeted v1.29.

Rebase was clean: scoutfs v1.30's diff against v1.29 touches btree,
forest, quota, totl, triggers, wkic, and xattr — none of the files
our series modifies.  No daemon, Makefile, or packaging changes;
this is a pure retag.

  git checkout v1.30
  git am --3way <the three existing patches>      # clean apply
  git format-patch v1.30..HEAD

Base bumped: v1.29 -> v1.30.

2026-04-22 16:14:54 -05:00

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scoutfs-notify

Observer-only file access notifications for ScoutFS, distributed as a rebasable git format-patch series plus a small Go userspace relay daemon. Layers onto each upstream release with minimal maintenance.

What the series adds

Three patches against the scoutfs source tree:

Kmod core — a per-mount 64 KiB ring of 64-byte notification records and a single-reader drain ioctl (SCOUTFS_IOC_READ_NOTIFY, nr 25). Emit is non-blocking, drop-on-full; the monotonic seq field exposes drops to consumers. Three percpu counters (notify_emitted, notify_dropped_ring_full, notify_reader_attached). No mount option, no sysfs toggle.
Kmod hooks — ->open wrapper and READ emit in scoutfs_file_aio_read / scoutfs_file_read_iter. Every hook is a single predicted-false branch when no reader is attached. Nothing in the data-waiter state machine is touched.
scoutfs-notifyd (Go) — userspace daemon that binds /run/scoutfs/<fsid>/notify.sock (AF_UNIX SOCK_SEQPACKET, mode 0600, root-only), drains the ring, and broadcasts each record to connected clients. Pure-stdlib Go; no external module dependencies. Shipped with a systemd template unit scoutfs-notifyd@<mountpoint>.service.

Base

Currently rebased against:

scoutfs v1.30

See base.txt.

Build dependencies added

On top of the stock scoutfs build requirements, patch 3 adds:

golang >= 1.26 on the build host (fetched from go.dev by the CI; no distro currently packages 1.26).

The Go build is offline (GOPROXY=off) — no network access required at build time. CGO_ENABLED=0 so the produced binary is a pure-Go static ELF.

Applying

./apply.sh /path/to/scoutfs

Runs git am --3way on each patch. For a tarball instead of a git tree, loop patch -p1 < patches/*.patch.

Rebasing onto a new upstream release

git fetch --tags
git checkout -B notify v1.30
git am --3way patches/*.patch
# resolve any conflicts, git am --continue
git format-patch v1.30..notify -o patches/
# update base.txt and commit

Tag history

v1.30-notify-1   (current — rebased onto scoutfs v1.30, no code changes)

v1.29-notify-4 (retired — last v1.29-base release) v1.29-notify-3 (retired — Go 1.21 toolchain) v1.29-notify-2 (retired — C daemon; had latent ring-size compile bug) v1.29-notify-1 (retired — shipped mount options)

Quick smoke test after installation

systemctl enable --now scoutfs-notifyd@mnt-scoutfs.service
FSID=$(stat -f -c %i /mnt/scoutfs)   # or use your scoutfs cli
socat - UNIX-CONNECT:/run/scoutfs/${FSID}/notify.sock | xxd | head
# touch some files in /mnt/scoutfs in another terminal

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