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William Gill 7708320f3b v1.28-notify-1: patches for scoutfs v1.28

Backport of the three notify patches onto scoutfs v1.28.  v1.28
predates SCOUTFS_IOC_PUNCH_OFFLINE (nr 24, introduced in v1.29),
so two trivial hunk fixes were needed during rebase:

  kmod/src/ioctl.h:
    drop the PUNCH_OFFLINE struct + define from the notify patch's
    context, since the surrounding definition doesn't exist in v1.28.
    Our SCOUTFS_IOC_READ_NOTIFY stays at nr 25 — Linux ioctl numbers
    are sparse and don't require the predecessor.

  kmod/src/ioctl.c:
    drop the PUNCH_OFFLINE dispatch case from the context for the
    same reason.

Resulting ABI is identical to v1.29-notify-1 and v1.30-notify-1:
SCOUTFS_IOC_READ_NOTIFY is nr 25 on all three, so scoutfs-notifyd
and any third-party consumer need zero per-version branching.

Branch purpose: scoutfs-build's multi-version pipeline checks out
this branch (via SCOUTFS_NOTIFY_REF=v1.28-notify-1) when building
kmod RPMs for scoutfs v1.28.

2026-04-23 09:01:48 -05:00

patches

v1.28-notify-1: patches for scoutfs v1.28

2026-04-23 09:01:48 -05:00

.gitattributes

Initial scoutfs-notify patch series for v1.29

2026-04-22 10:21:21 -05:00

apply.sh

apply.sh: set executable bit in git index

2026-04-22 16:12:24 -05:00

base.txt

v1.28-notify-1: patches for scoutfs v1.28

2026-04-23 09:01:48 -05:00

README.md

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

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

README.md

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