uvol: bump version to 1.1

manage volume state over ubus instead of the rootfs

Rework the volume lifecycle around blockd's ubus API, so volume state
lives entirely on the self-describing LVM/UBI backing store and never
leaks into the firmware rootfs.

- register active volumes with blockd over ubus (mount.uc) instead of
  spooling mounts into /etc/config/fstab (uci.uc)

- bootstrap .meta from 'uvol boot' and drop the broken 90-uvol-init
  uci-default

- run 'uvol boot' straight from the mount.ready trigger, and query
  'ubus call block status' at service start to cover storage already
  being ready

- defer removal of a volume whose backing device is still held, and
  reap it from the mount.umount trigger once it is free

- enforce content-addressed "<algo>-<hexdigest>" volumes in the
  dispatcher: reuse an existing volume of the same digest, verify
  every write

- verify a content-addressed write in place while the volume is still
  incomplete, reporting EBADMSG on mismatch instead of flipping
  volume state

- purge incomplete wo/wp leftovers on boot and reclaim an exactly
  matching one on create

- serialise mutating commands with a device-wide lock, plus a
  per-volume lock ordered after it so a slow write cannot stall other
  volumes

- add a grow-only 'resize' verb to both backends: lvextend plus the
  matching fs-grow tool for lvm, ubirsvol for ubi

- create ext4 volumes with a journal (was ext2) and request check_fs
  when registering a read-write volume

- declare read-only mounts to blockd rather than letting block guess
  from the filesystem

- reject non-numeric and non-positive sizes in create and resize

- report its own version

- simplify command line parsing (drop compatibility with ancient ucode)

Requires the matching fstools changes from
openwrt/openwrt@9b11fa4088.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

utils/uvol/Makefile

@@ -1,7 +1,7 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=uvol
-PKG_VERSION:=1.0
+PKG_VERSION:=1.1
 PKG_RELEASE:=1
 
 PKG_MAINTAINER:=Daniel Golle <daniel@makrotopia.org>
@@ -14,7 +14,7 @@ define Package/autopart
   CATEGORY:=Utilities
   SUBMENU:=Disc
   TITLE:=Automatically initialize LVM partition
-  DEPENDS:=+lvm2 +partx-utils +sfdisk
+  DEPENDS:=+lvm2 +partx-utils +sfdisk +e2fsprogs +mkf2fs +f2fsck
   PKGARCH=all
 endef
 
@@ -27,7 +27,7 @@ define Package/uvol
   CATEGORY:=Utilities
   SUBMENU:=Disc
   TITLE:=OpenWrt UBI/LVM volume abstraction
-  DEPENDS:=+blockd +ucode +ucode-mod-fs +ucode-mod-math +ucode-mod-uci
+  DEPENDS:=+blockd +ucode +ucode-mod-fs +ucode-mod-math +ucode-mod-uci +ucode-mod-ubus
   PKGARCH=all
 endef
 
@@ -67,14 +67,14 @@ define Package/autopart/install
 endef
 
 define Package/uvol/install
-	$(INSTALL_DIR) $(1)/etc/init.d $(1)/usr/lib/uvol/backends $(1)/usr/sbin $(1)/etc/uci-defaults
+	$(INSTALL_DIR) $(1)/etc/init.d $(1)/usr/lib/uvol/backends $(1)/usr/sbin
 	$(INSTALL_BIN) ./files/uvol.init $(1)/etc/init.d/uvol
 	$(INSTALL_DATA) ./files/blockdev_common.uc $(1)/usr/lib/uvol/
-	$(INSTALL_DATA) ./files/uci.uc $(1)/usr/lib/uvol/
+	$(INSTALL_DATA) ./files/mount.uc $(1)/usr/lib/uvol/
 	$(INSTALL_DATA) ./files/lvm.uc $(1)/usr/lib/uvol/backends/
 	$(INSTALL_DATA) ./files/ubi.uc $(1)/usr/lib/uvol/backends/
 	$(INSTALL_BIN) ./files/uvol $(1)/usr/sbin
-	$(INSTALL_BIN) ./files/uvol.defaults $(1)/etc/uci-defaults/90-uvol-init
+	$(SED) 's/@PKG_VERSION@/$(PKG_VERSION)/g' $(1)/usr/sbin/uvol
 endef
 
 $(eval $(call BuildPackage,autopart))

utils/uvol/files/lvm.uc

@@ -41,8 +41,8 @@ function lvm(cmd, ...args) {
 }
 
 function pvs() {
-	let fstab = cursor.get_all('fstab');
-	for (let k, section in fstab) {
+	let fstab = cursor ? cursor.get_all('fstab') : null;
+	for (let k, section in (fstab ?? {})) {
 		if (section['.type'] != 'uvol' || !section.vg_name)
 			continue;
 
@@ -95,6 +95,45 @@ function lvs(vg_name, vol_name, extra_exp) {
 	return ret;
 }
 
+function lvs_deleting(vg_name) {
+	let ret = [];
+	let tmp = lvm("lvs", "-o", "lv_active,lv_name,lv_full_name,lv_dm_path", "-S",
+		      sprintf("\"lvname=~^dd_.* && vg_name=%s\"", vg_name));
+	if (tmp && tmp.report.lv) {
+		ret = tmp.report.lv;
+		for (let r in ret)
+			r.lv_active = (r.lv_active == "active");
+	}
+	return ret;
+}
+
+function lvs_incomplete(vg_name, vol_name) {
+	let ret = [];
+	let tmp = lvm("lvs", "-o", "lv_active,lv_name,lv_full_name,lv_size", "-S",
+		      sprintf("\"lvname=~^w[op]_%s\$ && vg_name=%s\"", vol_name ?? ".*", vg_name));
+	if (tmp && tmp.report.lv) {
+		ret = tmp.report.lv;
+		for (let r in ret) {
+			r.lv_active = (r.lv_active == "active");
+			r.lv_size = +(rtrim(r.lv_size, "B"));
+		}
+	}
+	return ret;
+}
+
+// purge incomplete (wo_/wp_) leftovers; with match_size, only those of exactly
+// that allocated size (null purges all)
+function lvm_purge_incomplete(vol_name, match_size) {
+	for (let lv in lvs_incomplete(vg_name, vol_name)) {
+		if (match_size != null && lv.lv_size != match_size)
+			continue;
+		if (lv.lv_active)
+			lvm("lvchange", "-a", "n", lv.lv_full_name);
+		lvm("lvremove", "-y", lv.lv_full_name);
+	}
+	return 0;
+}
+
 function getdev(lv) {
 	if (!lv)
 		return null;
@@ -123,10 +162,8 @@ function lvm_init(ctx) {
 		return false;
 
 	vg = vgs(vg_name);
-	uvol_uci_add = ctx.uci_add;
-	uvol_uci_commit = ctx.uci_commit;
-	uvol_uci_remove = ctx.uci_remove;
-	uvol_uci_init = ctx.uci_init;
+	register = ctx.register;
+	unregister = ctx.unregister;
 	return true;
 }
 
@@ -198,7 +235,11 @@ function lvm_status(vol_name) {
 		return 2;
 
 	let mode = substr(res[0].lv_name, 0, 2);
-	if ((mode != "ro" && mode != "rw") || !res[0].lv_active)
+	if (mode == "wo")
+		return 22;
+	if (mode == "wp")
+		return 16;
+	if (!res[0].lv_active)
 		return 1;
 
 	return 0;
@@ -235,27 +276,28 @@ function lvm_updown(vol_name, up) {
 		   wildcard(lv.lv_path, "/dev/*/wp_*")))
 		return 22;
 
-	if (up)
-		uvol_uci_commit(vol_name);
-
-	if (lv.lv_active == up)
-		return 0;
-
 	if (!up) {
 		let devname = getdev(lv);
-		if (devname)
-			system(sprintf("umount /dev/%s", devname));
+		if (devname) {
+			unregister(devname);
+			system(sprintf("umount /dev/%s 2>/dev/null", devname));
+		}
 	}
 
-	let lvchange_r = lvm("lvchange", up?"-k":"-a", "n", lv.lv_full_name);
-	if (up && lvchange_r.retval != 0)
-		return lvchange_r.retval;
+	if (lv.lv_active != up) {
+		let lvchange_r = lvm("lvchange", up?"-k":"-a", "n", lv.lv_full_name);
+		if (up && lvchange_r.retval != 0)
+			return lvchange_r.retval;
 
-	lvchange_r = lvm("lvchange", up?"-a":"-k", "y", lv.lv_full_name);
-	if (lvchange_r.retval != 0)
-		return lvchange_r.retval;
+		lvchange_r = lvm("lvchange", up?"-a":"-k", "y", lv.lv_full_name);
+		if (lvchange_r.retval != 0)
+			return lvchange_r.retval;
+	}
 
-	return 0
+	if (up)
+		return register(vol_name, getdev(lv), substr(lv.lv_name, 0, 2) == "ro");
+
+	return 0;
 }
 
 function lvm_up(vol_name) {
@@ -271,16 +313,20 @@ function lvm_create(vol_name, vol_size, vol_mode) {
 		return 22;
 
 	vol_size = +vol_size;
-	if (vol_size <= 0)
+	if (vol_size != vol_size || vol_size <= 0)
 		return 22;
 
+	let size_ext = vol_size / vg.vg_extent_size;
+	if (vol_size % vg.vg_extent_size)
+		++size_ext;
+
+	// reclaim only an exact name+size retry; a size mismatch surfaces as EEXIST
+	lvm_purge_incomplete(vol_name, size_ext * vg.vg_extent_size);
+
 	let res = lvs(vg_name, vol_name);
 	if (res[0])
 		return 17;
 
-	let size_ext = vol_size / vg.vg_extent_size;
-	if (vol_size % vg.vg_extent_size)
-		++size_ext;
 	let lvmode, mode;
 	if (vol_mode == "ro" || vol_mode == "wo") {
 		lvmode = "r";
@@ -315,7 +361,7 @@ function lvm_create(vol_name, vol_size, vol_mode) {
 			return mkfs_ret;
 		}
 	} else {
-		let mkfs_ret = system(sprintf("/usr/sbin/mke2fs -F -L \"%s\" \"%s\"", vol_name, lv.lv_path));
+		let mkfs_ret = system(sprintf("/usr/sbin/mke2fs -F -t ext4 -O has_journal -L \"%s\" \"%s\"", vol_name, lv.lv_path));
 		if (mkfs_ret != 0) {
 			lvchange_r = lvm("lvchange", "-a", "n", lv.lv_full_name);
 			if (lvchange_r.retval != 0)
@@ -323,7 +369,6 @@ function lvm_create(vol_name, vol_size, vol_mode) {
 			return mkfs_ret;
 		}
 	}
-	uvol_uci_add(vol_name, sprintf("/dev/%s", getdev(lv)), "rw");
 
 	ret = lvm("lvchange", "-a", "n", lv.lv_full_name);
 	if (ret.retval != 0)
@@ -336,6 +381,98 @@ function lvm_create(vol_name, vol_size, vol_mode) {
 	return 0;
 }
 
+// identify the on-disk filesystem by superblock magic (no external tool needed)
+function fs_type(devpath) {
+	let f = fs.open(devpath, "r");
+	if (!f)
+		return null;
+	f.seek(1024);
+	let sb = f.read(58);
+	f.close();
+	if (type(sb) != "string" || length(sb) < 58)
+		return null;
+	if (ord(sb, 0) == 0x10 && ord(sb, 1) == 0x20 && ord(sb, 2) == 0xf5 && ord(sb, 3) == 0xf2)
+		return "f2fs";
+	if (ord(sb, 56) == 0x53 && ord(sb, 57) == 0xef)
+		return "ext";
+	return null;
+}
+
+// Grow a rw volume in place; the fs (ext4 or f2fs, chosen at create by size) is
+// grown with its own tool. Shrink is refused. The fs-grow tool is an optional
+// dependency: if absent, report and refuse rather than grow the LV past the fs.
+function lvm_resize(vol_name, vol_size) {
+	if (!vol_name || !vg_name)
+		return 22;
+
+	vol_size = +vol_size;
+	if (vol_size != vol_size || vol_size <= 0)
+		return 22;
+
+	let res = lvs(vg_name, vol_name);
+	if (!res[0])
+		return 2;
+
+	if (substr(res[0].lv_name, 0, 2) != "rw")
+		return 1;
+
+	let size_ext = vol_size / vg.vg_extent_size;
+	if (vol_size % vg.vg_extent_size)
+		++size_ext;
+
+	let new_size = size_ext * vg.vg_extent_size;
+	if (new_size == +res[0].lv_size)
+		return 0;
+	if (new_size < +res[0].lv_size)
+		return 22;
+
+	let dev = getdev(res[0]);
+	if (!dev)
+		return 2;
+
+	let fstype = fs_type(sprintf("/dev/%s", dev));
+	let tool = (fstype == "f2fs") ? "resize.f2fs" : (fstype == "ext") ? "resize2fs" : null;
+	if (!tool) {
+		warn(sprintf("uvol: cannot identify filesystem on %s; not resizing\n", vol_name));
+		return 95;
+	}
+
+	// the fs-grow tool first, so the LV is never left larger than its filesystem
+	if (system(sprintf("command -v %s >/dev/null 2>&1", tool)) != 0) {
+		warn(sprintf("uvol: %s not found; install %s to grow this %s volume\n",
+			     tool, (fstype == "f2fs") ? "f2fs-tools" : "e2fsprogs", fstype));
+		return 95;
+	}
+
+	let ret = lvm("lvextend", "-l", size_ext, res[0].lv_full_name);
+	if (ret.retval != 0)
+		return ret.retval;
+
+	if (fstype == "f2fs")
+		return system(sprintf("resize.f2fs /dev/%s", dev));
+
+	return system(sprintf("resize2fs /dev/%s", dev));
+}
+
+// Reap volumes marked for deferred deletion (dd_ prefix). A volume can only be
+// reaped once its backing device has no holder; blockd signals that moment with
+// a mount.umount notification (autofs idle-expiry), which triggers 'uvol reap'.
+// Still-held volumes are left for the next signal (or the boot sweep).
+function lvm_reap() {
+	for (let dd in lvs_deleting(vg_name)) {
+		let dev = getdev(dd);
+		if (dd.lv_active) {
+			let r = lvm("lvchange", "-a", "n", dd.lv_full_name);
+			if (r.retval != 0)
+				continue;
+		}
+		if (dev)
+			unregister(dev);
+		lvm("lvremove", "-y", dd.lv_full_name);
+	}
+	return 0;
+}
+
 function lvm_remove(vol_name) {
 	if (!vol_name || !vg_name)
 		return 22;
@@ -344,16 +481,15 @@ function lvm_remove(vol_name) {
 	if (!res[0])
 		return 2;
 
-	if (res[0].lv_active)
-		return 16;
-
-	let ret = lvm("lvremove", "-y", res[0].lv_full_name);
+	// mark for deletion: rename to the dd_ state (works whether the volume is
+	// active or not, and hides it from list/status). reap removes it now if the
+	// device is already free, otherwise blockd's mount.umount triggers reap once
+	// the holder releases it.
+	let ret = lvm("lvrename", vg_name, res[0].lv_name, sprintf("dd_%s", vol_name));
 	if (ret.retval != 0)
 		return ret.retval;
 
-	uvol_uci_remove(vol_name);
-	uvol_uci_commit(vol_name);
-	return 0;
+	return lvm_reap();
 }
 
 function lvm_dd(in_fd, out_fd, vol_size) {
@@ -369,7 +505,7 @@ function lvm_dd(in_fd, out_fd, vol_size) {
 	return rem;
 }
 
-function lvm_write(vol_name, vol_size) {
+function lvm_write(vol_name, vol_size, verify) {
 	if (!vol_name || !vg_name)
 		return 22;
 
@@ -382,70 +518,74 @@ function lvm_write(vol_name, vol_size) {
 	if (vol_size > lv.lv_size)
 		return 27;
 
-	if (wildcard(lv.lv_path, "/dev/*/wo_*")) {
-		let ret = lvm("lvchange", "-p", "rw", lv.lv_full_name);
-		if (ret.retval != 0)
-			return ret.retval;
-
-		let ret = lvm("lvchange", "-a", "y", lv.lv_full_name);
-		if (ret.retval != 0)
-			return ret.retval;
-
-		let volfile = fs.open(lv.lv_path, "w");
-		let ret = lvm_dd(fs.stdin, volfile, vol_size);
-		volfile.close();
-		if (ret < 0) {
-			printf("more %d bytes data than given size!\n", -ret);
-		}
-
-		if (ret > 0) {
-			printf("reading finished %d bytes before given size!\n", ret);
-		}
-
-		uvol_uci_add(vol_name, sprintf("/dev/%s", getdev(lv)), "ro");
-
-		let ret = lvm("lvchange", "-a", "n", lv.lv_full_name);
-		if (ret.retval != 0)
-			return ret.retval;
-
-		let ret = lvm("lvchange", "-p", "r", lv.lv_full_name);
-		if (ret.retval != 0)
-			return ret.retval;
-
-		let ret = lvm("lvrename", vg_name, sprintf("wo_%s", vol_name), sprintf("ro_%s", vol_name));
-		if (ret.retval != 0)
-			return ret.retval;
-
-	} else {
+	if (!wildcard(lv.lv_path, "/dev/*/wo_*"))
 		return 22;
+
+	let ret = lvm("lvchange", "-p", "rw", lv.lv_full_name);
+	if (ret.retval != 0)
+		return ret.retval;
+
+	let ret = lvm("lvchange", "-a", "y", lv.lv_full_name);
+	if (ret.retval != 0)
+		return ret.retval;
+
+	let volfile = fs.open(lv.lv_path, "w");
+	let rem = lvm_dd(fs.stdin, volfile, vol_size);
+	volfile.close();
+	if (rem < 0) {
+		printf("more %d bytes data than given size!\n", -rem);
 	}
+
+	if (rem > 0) {
+		printf("reading finished %d bytes before given size!\n", rem);
+	}
+
+	if (verify && !verify(lv.lv_path)) {
+		lvm("lvchange", "-a", "n", lv.lv_full_name);
+		lvm("lvchange", "-p", "r", lv.lv_full_name);
+		return 74;
+	}
+
+	let ret = lvm("lvchange", "-a", "n", lv.lv_full_name);
+	if (ret.retval != 0)
+		return ret.retval;
+
+	let ret = lvm("lvchange", "-p", "r", lv.lv_full_name);
+	if (ret.retval != 0)
+		return ret.retval;
+
+	let ret = lvm("lvrename", vg_name, sprintf("wo_%s", vol_name), sprintf("ro_%s", vol_name));
+	if (ret.retval != 0)
+		return ret.retval;
+
 	return 0;
 }
 
 function lvm_detect() {
-	let temp_up = [];
-	let inactive_lv = lvs(vg_name, null, "lv_skip_activation!=0");
-	for (let lv in inactive_lv) {
-		lvm("lvchange", "-k", "n", lv.lv_full_name);
-		lvm("lvchange", "-a", "y", lv.lv_full_name);
-		push(temp_up, lv.lv_full_name);
-	}
-	sleep(1000);
-	uvol_uci_init();
 	for (let lv in lvs(vg_name)) {
-		let vol_name = substr(lv.lv_name, 3);
-		let vol_mode = substr(lv.lv_name, 0, 2);
-		uvol_uci_add(vol_name, sprintf("/dev/%s", getdev(lv)), vol_mode);
-	}
-	uvol_uci_commit();
-	for (let lv_full_name in temp_up) {
-		lvm("lvchange", "-a", "n", lv_full_name);
-		lvm("lvchange", "-k", "y", lv_full_name);
+		if (!lv.lv_active)
+			continue;
+
+		let mode = substr(lv.lv_name, 0, 2);
+		if (mode != "ro" && mode != "rw")
+			continue;
+
+		register(substr(lv.lv_name, 3), getdev(lv), mode == "ro");
 	}
 	return 0;
 }
 
 function lvm_boot() {
+	// clear crash/power-loss leftovers before activating
+	lvm_reap();
+	lvm_purge_incomplete();
+	for (let lv in lvs(vg_name, null, "lv_skip_activation=0")) {
+		let mode = substr(lv.lv_name, 0, 2);
+		if (mode != "ro" && mode != "rw")
+			continue;
+
+		lvm_up(substr(lv.lv_name, 3));
+	}
 	return 0;
 }
 
@@ -464,5 +604,7 @@ backend.device = lvm_device;
 backend.up = lvm_up;
 backend.down = lvm_down;
 backend.create = lvm_create;
+backend.resize = lvm_resize;
 backend.remove = lvm_remove;
+backend.reap = lvm_reap;
 backend.write = lvm_write;

utils/uvol/files/mount.uc

@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+// blockd mount registration for uvol
+//  (c) 2022 Daniel Golle <daniel@makrotopia.org>
+//
+// Register volumes with blockd over ubus instead of writing /etc/config/fstab,
+// so volume state stays on the self-describing backing store and never leaks
+// into the firmware rootfs.
+
+let mount_fs = require("fs");
+let mount_ubus = require("ubus");
+
+let uvol_target = function(vol_name) {
+	return sprintf("/tmp/run/uvol/%s", vol_name);
+};
+
+uvol_mount = {
+	register: function(vol_name, dev_name, read_only) {
+		if (!dev_name)
+			return 22;
+		if (substr(vol_name, 0, 1) == "." && vol_name != ".meta")
+			return 1;
+
+		let target = uvol_target(vol_name);
+		let st = mount_fs.lstat(target);
+		if (st && st.type == "link")
+			mount_fs.unlink(target);
+		else if (st && st.type == "directory")
+			mount_fs.rmdir(target);
+
+		let data = {
+			device: dev_name,
+			target: target,
+			autofs: 1,
+		};
+		// declare the volume's read-only-ness to blockd, which carries it
+		// to block as a mount option; block never guesses from the fs type.
+		if (read_only)
+			data.options = "ro";
+		else
+			data.check_fs = 1;
+
+		mount_ubus.call({
+			object: "block",
+			method: "hotplug",
+			data: data,
+		});
+		return mount_ubus.error() ? -1 : 0;
+	},
+
+	unregister: function(dev_name) {
+		if (!dev_name)
+			return 22;
+
+		mount_ubus.call({
+			object: "block",
+			method: "hotplug",
+			data: {
+				device: dev_name,
+				remove: 1,
+			},
+		});
+		return mount_ubus.error() ? -1 : 0;
+	}
+};

utils/uvol/files/ubi.uc

@@ -50,10 +50,6 @@ function mkubifs(vol_dev) {
 	return 0;
 }
 
-function block_hotplug(action, devname) {
-	return system(sprintf("ACTION=%s DEVNAME=%s /sbin/block hotplug", action, devname));
-}
-
 function ubi_init(ctx) {
 	cursor = ctx.cursor;
 	fs = ctx.fs;
@@ -76,10 +72,8 @@ function ubi_init(ctx) {
 
 	ebsize = read_file(sprintf("%s/eraseblock_size", ubidevpath));
 
-	uvol_uci_add = ctx.uci_add;
-	uvol_uci_commit = ctx.uci_commit;
-	uvol_uci_remove = ctx.uci_remove;
-	uvol_uci_init = ctx.uci_init;
+	register = ctx.register;
+	unregister = ctx.unregister;
 
 	return true;
 }
@@ -137,10 +131,6 @@ function ubi_device(vol_name) {
 }
 
 function ubi_create(vol_name, vol_size, vol_mode) {
-	let vol_dev = ubi_get_dev(vol_name);
-	if (vol_dev)
-		return 17;
-
 	let mode;
 	if (vol_mode == "ro" || vol_mode == "wo")
 		mode = "wo";
@@ -152,6 +142,13 @@ function ubi_create(vol_name, vol_size, vol_mode) {
 	let vol_size = +vol_size;
 	if (vol_size <= 0)
 		return 22;
+
+	ubi_purge_incomplete(vol_name, vol_size);
+
+	let vol_dev = ubi_get_dev(vol_name);
+	if (vol_dev)
+		return 17;
+
 	let ret = system(sprintf("ubimkvol /dev/%s -N \"uvol-%s-%s\" -s %d", ubidev, mode, vol_name, vol_size));
 	if (ret != 0)
 		return ret;
@@ -171,8 +168,6 @@ function ubi_create(vol_name, vol_size, vol_mode) {
 	if (ret != 0)
 		return ret;
 
-	uvol_uci_add(vol_name, sprintf("/dev/%s", vol_dev), "rw");
-
 	let ret = system(sprintf("ubirename /dev/%s \"uvol-wp-%s\" \"uvol-wd-%s\"", ubidev, vol_name, vol_name));
 	if (ret != 0)
 		return ret;
@@ -180,25 +175,111 @@ function ubi_create(vol_name, vol_size, vol_mode) {
 	return 0;
 }
 
+// Grow a rw volume; UBIFS uses the new size directly. Shrink is refused.
+function ubi_resize(vol_name, vol_size) {
+	vol_size = +vol_size;
+	if (vol_size <= 0)
+		return 22;
+
+	let vol_dev = ubi_get_dev(vol_name);
+	if (!vol_dev)
+		return 2;
+
+	if (vol_get_mode(vol_dev) != "rw")
+		return 1;
+
+	let leb = +read_file(sprintf("/sys/class/ubi/%s/usable_eb_size", vol_dev));
+	let cur_lebs = +read_file(sprintf("/sys/class/ubi/%s/reserved_ebs", vol_dev));
+	let req_lebs = vol_size / leb;
+	if (vol_size % leb)
+		++req_lebs;
+
+	if (req_lebs == cur_lebs)
+		return 0;
+	if (req_lebs < cur_lebs)
+		return 22;
+
+	return system(sprintf("ubirsvol /dev/%s -N \"uvol-rw-%s\" -s %d", ubidev, vol_name, vol_size));
+}
+
+function ubi_get_deleting() {
+	let ret = [];
+	for (vol_dir in fs.glob(sprintf("/sys/class/ubi/%s_*", ubidev))) {
+		let vol_ubiname = read_file(sprintf("%s/name", vol_dir));
+		if (!wildcard(vol_ubiname, "uvol-dd-*"))
+			continue;
+
+		push(ret, fs.basename(vol_dir));
+	}
+	return ret;
+}
+
+function ubi_get_incomplete(vol_name) {
+	let ret = [];
+	let pat = vol_name ? sprintf("uvol-w[op]-%s", vol_name) : "uvol-w[op]-*";
+	for (vol_dir in fs.glob(sprintf("/sys/class/ubi/%s_*", ubidev))) {
+		let vol_ubiname = read_file(sprintf("%s/name", vol_dir));
+		if (!wildcard(vol_ubiname, pat))
+			continue;
+		push(ret, {
+			dev: fs.basename(vol_dir),
+			lebs: +read_file(sprintf("%s/reserved_ebs", vol_dir)),
+			leb: +read_file(sprintf("%s/usable_eb_size", vol_dir)),
+		});
+	}
+	return ret;
+}
+
+// purge incomplete (wo/wp) leftovers; with match_size, only those whose
+// reservation matches that size (null purges all)
+function ubi_purge_incomplete(vol_name, match_size) {
+	for (let v in ubi_get_incomplete(vol_name)) {
+		if (match_size != null) {
+			if (!v.leb || !v.lebs)
+				continue;
+			let want = match_size / v.leb;
+			if (match_size % v.leb)
+				want++;
+			if (v.lebs != want)
+				continue;
+		}
+		let volnum = split(v.dev, "_")[1];
+		system(sprintf("ubirmvol /dev/%s -n %d 2>/dev/null", ubidev, volnum));
+	}
+	return 0;
+}
+
+function ubi_reap() {
+	for (let vol_dev in ubi_get_deleting()) {
+		let volnum = split(vol_dev, "_")[1];
+		let blkdev = sprintf("ubiblock%s", substr(vol_dev, 3));
+		let isblock = fs.access(sprintf("/dev/%s", blkdev), "r");
+
+		if (isblock && system(sprintf("ubiblock --remove /dev/%s 2>/dev/null", vol_dev)) != 0)
+			continue;
+
+		if (!isblock)
+			system(sprintf("umount /dev/%s 2>/dev/null", vol_dev));
+
+		if (system(sprintf("ubirmvol /dev/%s -n %d 2>/dev/null", ubidev, volnum)) != 0)
+			continue;
+
+		unregister(isblock ? blkdev : vol_dev);
+	}
+	return 0;
+}
+
 function ubi_remove(vol_name) {
 	let vol_dev = ubi_get_dev(vol_name);
 	if (!vol_dev)
 		return 2;
 
-	let vol_mode = vol_get_mode(vol_dev);
-	if (vol_mode == "rw" || vol_mode == "ro")
-		return 16;
-
-	let volnum = split(vol_dev, "_")[1];
-
-	let ret = system(sprintf("ubirmvol /dev/%s -n %d", ubidev, volnum));
+	let vol_ubiname = read_file(sprintf("/sys/class/ubi/%s/name", vol_dev));
+	let ret = system(sprintf("ubirename /dev/%s \"%s\" \"uvol-dd-%s\"", ubidev, vol_ubiname, vol_name));
 	if (ret != 0)
 		return ret;
 
-	uvol_uci_remove(vol_name);
-	uvol_uci_commit(vol_name);
-
-	return 0;
+	return ubi_reap();
 }
 
 function ubi_up(vol_name) {
@@ -214,19 +295,22 @@ function ubi_up(vol_name) {
 	else if (vol_mode == "wp")
 		return 16;
 
-	uvol_uci_commit(vol_name);
 	if (vol_mode == "rd") {
 		let ret = system(sprintf("ubirename /dev/%s \"uvol-rd-%s\" \"uvol-ro-%s\"", ubidev, vol_name, vol_name));
 		if (ret != 0)
 			return ret;
 
-		return system(sprintf("ubiblock --create /dev/%s", vol_dev));
+		ret = system(sprintf("ubiblock --create /dev/%s", vol_dev));
+		if (ret != 0)
+			return ret;
+
+		return register(vol_name, sprintf("ubiblock%s", substr(vol_dev, 3)), true);
 	} else if (vol_mode == "wd") {
 		let ret = system(sprintf("ubirename /dev/%s \"uvol-wd-%s\" \"uvol-rw-%s\"", ubidev, vol_name, vol_name));
 		if (ret != 0)
 			return ret;
 
-		return block_hotplug("add", vol_dev);
+		return register(vol_name, vol_dev, false);
 	}
 	return 0;
 }
@@ -244,14 +328,15 @@ function ubi_down(vol_name) {
 	else if (vol_mode == "wp")
 		return 16;
 	else if (vol_mode == "ro") {
+		unregister(sprintf("ubiblock%s", substr(vol_dev, 3)));
 		system(sprintf("umount /dev/ubiblock%s 2>&1 >/dev/null", substr(vol_dev, 3)));
 		system(sprintf("ubiblock --remove /dev/%s", vol_dev));
 		let ret = system(sprintf("ubirename /dev/%s \"uvol-ro-%s\" \"uvol-rd-%s\"", ubidev, vol_name, vol_name));
 		return ret;
 	} else if (vol_mode == "rw") {
+		unregister(vol_dev);
 		system(sprintf("umount /dev/%s 2>&1 >/dev/null", vol_dev));
 		let ret = system(sprintf("ubirename /dev/%s \"uvol-rw-%s\" \"uvol-wd-%s\"", ubidev, vol_name, vol_name));
-		block_hotplug("remove", vol_dev);
 		return ret;
 	}
 	return 0;
@@ -279,64 +364,38 @@ function ubi_list(search_name) {
 	return volumes;
 }
 
-function ubi_detect() {
-	let tmpdev = [];
+function ubi_register_active() {
 	for (vol_dir in fs.glob(sprintf("/sys/class/ubi/%s_*", ubidev))) {
 		let vol_ubiname = read_file(sprintf("%s/name", vol_dir));
-
-		if (!wildcard(vol_ubiname, "uvol-r[od]-*"))
-			continue;
-
-		let vol_name = substr(vol_ubiname, 8);
-		let vol_mode = substr(vol_ubiname, 5, 2);
-		let vol_dev = fs.basename(vol_dir);
-
-		ret = system(sprintf("ubiblock --create /dev/%s", vol_dev));
-		if (ret)
-			continue;
-
-		if (vol_mode == "rd")
-			push(tmpdev, vol_dev);
-	}
-
-	uvol_uci_init();
-
-	for (vol_dir in fs.glob(sprintf("/sys/class/ubi/%s_*", ubidev))) {
-		let vol_ubiname = read_file(sprintf("%s/name", vol_dir));
-		if (!wildcard(vol_ubiname, "uvol-[rw][wod]-*"))
+		if (!wildcard(vol_ubiname, "uvol-r[ow]-*"))
 			continue;
 
 		let vol_dev = fs.basename(vol_dir);
 		let vol_name = substr(vol_ubiname, 8);
 		let vol_mode = substr(vol_ubiname, 5, 2);
 
-		if (vol_mode == "ro" || vol_mode == "rd")
-			uvol_uci_add(vol_name, sprintf("/dev/ubiblock%s", substr(vol_dev, 3)), "ro");
-		else if (vol_mode == "rw" || vol_mode == "wd")
-			uvol_uci_add(vol_name, sprintf("/dev/%s", vol_dev), "rw");
+		if (vol_mode == "ro") {
+			system(sprintf("ubiblock --create /dev/%s", vol_dev));
+			register(vol_name, sprintf("ubiblock%s", substr(vol_dev, 3)), true);
+		} else {
+			register(vol_name, vol_dev, false);
+		}
 	}
-
-	uvol_uci_commit();
-
-	for (vol_dev in tmpdev)
-		system(sprintf("ubiblock --remove /dev/%s", vol_dev));
-
 	return 0;
 }
 
-function ubi_boot() {
-	for (vol_dir in fs.glob(sprintf("/sys/class/ubi/%s_*", ubidev))) {
-		let vol_dev = fs.basename(vol_dir);
-		let vol_ubiname = read_file(sprintf("%s/name", vol_dir));
-
-		if (!wildcard(vol_ubiname, "uvol-ro-*"))
-			continue;
-
-		system(sprintf("ubiblock --create /dev/%s", vol_dev));
-	}
+function ubi_detect() {
+	return ubi_register_active();
 }
 
-function ubi_write(vol_name, write_size) {
+function ubi_boot() {
+	// clear crash/power-loss leftovers before activating
+	ubi_reap();
+	ubi_purge_incomplete();
+	return ubi_register_active();
+}
+
+function ubi_write(vol_name, write_size, verify) {
 	let vol_dev = ubi_get_dev(vol_name);
 	if (!vol_dev)
 		return 2;
@@ -349,13 +408,13 @@ function ubi_write(vol_name, write_size) {
 	if (vol_mode != "wo")
 		return 22;
 
-	let ret = system(sprintf("ubiupdatevol -s %s /dev/%s -", write_size, vol_dev));
+	let ret = system(sprintf("ubiupdatevol -s %d /dev/%s -", write_size, vol_dev));
 	if (ret)
 		return ret;
 
-	system(sprintf("ubiblock --create /dev/%s", vol_dev));
-	uvol_uci_add(vol_name, sprintf("/dev/ubiblock%s", substr(vol_dev, 3)), "ro");
-	system(sprintf("ubiblock --remove /dev/%s", vol_dev));
+	if (verify && !verify(sprintf("/dev/%s", vol_dev)))
+		return 74;
+
 	system(sprintf("ubirename /dev/%s \"uvol-wo-%s\" \"uvol-rd-%s\"", ubidev, vol_name, vol_name));
 
 	return 0;
@@ -376,5 +435,7 @@ backend.device = ubi_device;
 backend.up = ubi_up;
 backend.down = ubi_down;
 backend.create = ubi_create;
+backend.resize = ubi_resize;
 backend.remove = ubi_remove;
+backend.reap = ubi_reap;
 backend.write = ubi_write;

utils/uvol/files/uci.uc

@@ -1,137 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-// UCI tools for uvol
-//  (c) 2022 Daniel Golle <daniel@makrotopia.org>
-
-let uci_spooldir = "/var/spool/uvol";
-let init_spooldir = function(void) {
-	parentdir = fs.stat(fs.dirname(uci_spooldir));
-	if (!parentdir || parentdir.type != "directory")
-		fs.mkdir(fs.dirname(uci_spooldir), 0755);
-	fs.mkdir(uci_spooldir, 0700);
-};
-
-uvol_uci = {
-	uvol_uci_add: function(vol_name, dev_name, mode) {
-		try {
-			let autofs = false;
-			let uuid;
-			let target;
-			if (mode == "ro")
-				autofs = true;
-
-			let uciname = replace(vol_name, /[-.]/g, "_");
-			uciname = replace(uciname, /!([:alnum:]_)/g, "");
-			let bdinfo_p = fs.popen("/sbin/block info");
-			let bdinfo_l;
-			while (bdinfo_l = bdinfo_p.read("line")) {
-				if (substr(bdinfo_l, 0, length(dev_name) + 1) != dev_name + ":")
-					continue;
-				let bdinfo_e = split(bdinfo_l, " ");
-				shift(bdinfo_e);
-				for (let bdinfo_a in bdinfo_e) {
-					let bdinfo_v = split(bdinfo_a, "=");
-					if (bdinfo_v[0] && bdinfo_v[0] == "UUID") {
-						uuid = trim(bdinfo_v[1], "\"");
-						break;
-					}
-				}
-				break;
-			}
-
-			if (!uuid)
-				return 22;
-
-			if (uciname == "_meta")
-				target = "/tmp/run/uvol/.meta";
-			else if (substr(uciname, 0, 1) == "_")
-				return 1;
-			else
-				target = sprintf("/tmp/run/uvol/%s", vol_name);
-
-			init_spooldir();
-			let remspool = sprintf("%s/remove-%s", uci_spooldir, uciname);
-			if (fs.stat(remspool))
-				fs.unlink(remspool);
-
-			let addobj = {};
-			addobj.name=uciname;
-			addobj.uuid=uuid;
-			addobj.target=target;
-			addobj.options=mode;
-			addobj.autofs=autofs;
-			addobj.enabled=true;
-
-			let spoolfile = fs.open(sprintf("%s/add-%s", uci_spooldir, uciname), "w");
-			spoolfile.write(addobj);
-			spoolfile.close();
-		} catch(e) {
-			printf("adding UCI section to spool failed");
-			return -1;
-		}
-		return 0;
-	},
-
-	uvol_uci_remove: function(vol_name) {
-		let uciname = replace(vol_name, /[-.]/g, "_");
-		uciname = replace(uciname, /!([:alnum:]_)/g, "");
-
-		let addspool = sprintf("%s/add-%s", uci_spooldir, uciname);
-		if (fs.stat(addspool)) {
-			fs.unlink(addspool);
-			return 0;
-		}
-		init_spooldir();
-		let spoolfile = fs.open(sprintf("%s/remove-%s", uci_spooldir, uciname), "w");
-		spoolfile.write(uciname);
-		spoolfile.close();
-		return 0;
-	},
-
-	uvol_uci_commit: function(vol_name) {
-		try {
-			let uciname = null;
-			if (vol_name) {
-				uciname = replace(vol_name, /[-.]/g, "_");
-				uciname = replace(uciname, /!([:alnum:]_)/g, "");
-			}
-
-			for (let file in fs.glob(sprintf("%s/*-%s", uci_spooldir, uciname?uciname:"*"))) {
-				let action = split(fs.basename(file), "-")[0];
-				let spoolfd = fs.open(file, "r");
-				let spoolstr = spoolfd.read("all");
-				spoolfd.close();
-				fs.unlink(file);
-				if (action == "remove") {
-					cursor.delete("fstab", spoolstr);
-				} else if (action == "add") {
-					let spoolobj = json(spoolstr);
-					cursor.set("fstab", spoolobj.name, "mount");
-					for (key in keys(spoolobj)) {
-						if (key == "name")
-							continue;
-
-						cursor.set("fstab", spoolobj.name, key, spoolobj[key]);
-					}
-				}
-			}
-			cursor.commit();
-		} catch(e) {
-			printf("committing UCI spool failed");
-			return -1;
-		}
-		return 0;
-	},
-
-	uvol_uci_init: function () {
-		cursor.load("fstab");
-		let f = cursor.get("fstab", "@uvol[0]", "initialized");
-		if (f == 1)
-			return 0;
-
-		cursor.add("fstab", "uvol");
-		cursor.set("fstab", "@uvol[-1]", "initialized", true);
-		cursor.commit();
-		cursor.unload("fstab");
-		return 0;
-	}
-};

utils/uvol/files/uvol

@@ -3,10 +3,13 @@
 // uvol - storage volume manager for OpenWrt
 //  (c) 2022 Daniel Golle <daniel@makrotopia.org>
 
-let help_output = "uvol storage volume manager
+let uvol_version = "@PKG_VERSION@";
+
+let help_output = `uvol ${uvol_version} - storage volume manager
 syntax: uvol command ...
 
 commands:
+  version			show version and exit
   boot				get active volumes ready (called on boot)
   free				show number of bytes available
   total				show total number of bytes
@@ -25,7 +28,20 @@ commands:
                  1 - volume is not ready for use
                  2 - volume doesn't exist
   write volname size		write to volume from stdin, size in bytes
-";
+`;
+
+let cmd = shift(ARGV);
+
+// answer before probing for a backend, so both work on a system without storage
+if (cmd == "version" || cmd == "--version" || cmd == "-v" || cmd == "-V") {
+	printf("uvol %s\n", uvol_version);
+	return 0;
+}
+
+if (!cmd || cmd == "-h" || cmd == "--help" || cmd == "help") {
+	printf("%s", help_output);
+	return cmd?0:22;
+}
 
 let fs = require("fs");
 let uci = require("uci");
@@ -34,11 +50,9 @@ let cursor = uci ? uci.cursor() : null;
 let ctx = {};
 ctx.cursor = cursor;
 ctx.fs = fs;
-include("/usr/lib/uvol/uci.uc");
-ctx.uci_add = uvol_uci.uvol_uci_add;
-ctx.uci_remove = uvol_uci.uvol_uci_remove;
-ctx.uci_commit = uvol_uci.uvol_uci_commit;
-ctx.uci_init = uvol_uci.uvol_uci_init;
+include("/usr/lib/uvol/mount.uc");
+ctx.register = uvol_mount.register;
+ctx.unregister = uvol_mount.unregister;
 
 let backend = null;
 let tried_backends = [];
@@ -64,29 +78,55 @@ if (!backend) {
 	exit(2);
 }
 
-// The below code is needed as older versions of ucode pass the complete cmdline via ARGV
-// Once we can rely in more recent ucode the while loop can be replaced by simply
-// let cmd = shift(ARGV);
-let skip = null;
-let cmd = null;
-let skip_argv = ["/usr/bin/ucode", "-R", "/usr/sbin/uvol"];
-while (skip = shift(ARGV)) {
-	if (skip != shift(skip_argv)) {
-		cmd = skip;
-		break;
-	}
-}
-
-if (!cmd || cmd == "-h" || cmd == "help") {
-	printf("%s", help_output);
-	return cmd?0:22;
-}
-
 if (!(cmd in keys(backend))) {
 	printf("command %s not found\n", cmd);
 	return 22;
 }
 
+// serialise state-mutating commands device-wide; released on process exit.
+// create and write additionally serialise per volume, as create may reclaim
+// an incomplete volume of the same name and size while a writer is still
+// streaming to it. The device-wide lock is always taken before the
+// per-volume lock; write takes only the per-volume one so a slow stream
+// does not stall operations on other volumes.
+let uvol_mutating = [ "boot", "detect", "create", "up", "down", "remove", "reap", "resize" ];
+let uvol_vol_mutating = [ "create", "write" ];
+let uvol_lockfd;
+let uvol_vol_lockfd;
+if (index(uvol_mutating, cmd) >= 0 || index(uvol_vol_mutating, cmd) >= 0)
+	fs.mkdir("/tmp/run", 0755);
+if (index(uvol_mutating, cmd) >= 0) {
+	uvol_lockfd = fs.open("/tmp/run/uvol.lock", "a");
+	if (uvol_lockfd)
+		uvol_lockfd.lock("x");
+}
+if (index(uvol_vol_mutating, cmd) >= 0 && ARGV[0]) {
+	uvol_vol_lockfd = fs.open(sprintf("/tmp/run/uvol.lock.%s", ARGV[0]), "a");
+	if (uvol_vol_lockfd)
+		uvol_vol_lockfd.lock("x");
+}
+
+let meta_init = function() {
+	let sz = backend.size(".meta");
+	if (type(sz) != "string" || +sz <= 0) {
+		let metasz = +backend.total() / 10240;
+		if (metasz < 4194304)
+			metasz = 4194304;
+		if (metasz > +backend.free())
+			return;
+		if (backend.create(".meta", sprintf("%d", metasz), "rw") != 0)
+			return;
+	}
+	backend.up(".meta");
+	fs.mkdir("/tmp/run/uvol/.meta/apk", 0755);
+};
+
+if (cmd == "boot") {
+	backend.boot();
+	meta_init();
+	exit(0);
+}
+
 let json_output = false;
 if (ARGV[0] == "-j") {
 	json_output = true;
@@ -110,6 +150,69 @@ let legacy_output = function(var) {
 	return out;
 };
 
+// Content-addressed volumes are named "<algo>-<hexdigest>"; the name carries the
+// expected digest of its content. Validation lives here in the generic layer so
+// backends stay plain storage. Add an entry to ca_algos to support a new digest.
+let ca_algos = {
+	sha256: { cmd: "sha256sum", len: 64 },
+};
+
+let ca_parse = function(name) {
+	let m = match(name, /^([0-9a-z]+)-([0-9a-f]+)$/);
+	if (!m)
+		return null;
+	let a = ca_algos[m[1]];
+	if (!a || length(m[2]) != a.len)
+		return null;
+	return { cmd: a.cmd, hash: m[2] };
+};
+
+let ca_digest = function(cmd, size, path) {
+	let src = path ? sprintf("head -c %d %s", size, path) : sprintf("head -c %d", size);
+	let f = fs.popen(sprintf("%s | %s", src, cmd), "r");
+	if (!f)
+		return null;
+	let line = f.read("line");
+	f.close();
+	return split(trim(line ?? ""), " ")[0];
+};
+
+// complete means the volume exists and has left the write-only state:
+// ready (0) or merely down (1); incomplete volumes report 22 or 16
+let ca_complete = function(name) {
+	let st = backend.status(name);
+	return st == 0 || st == 1;
+};
+
+let ca_mismatch = function(name) {
+	printf("content hash mismatch for %s\n", name);
+	exit(74);
+};
+
+if (cmd == "create" && ca_parse(ARGV[0])) {
+	let ret = backend.create(...ARGV);
+	exit(ret == 17 ? 0 : ret);
+}
+
+if (cmd == "write") {
+	let ca = ca_parse(ARGV[0]);
+	if (ca) {
+		let size = +ARGV[1];
+		if (ca_complete(ARGV[0])) {
+			if (ca_digest(ca.cmd, size, null) != ca.hash)
+				ca_mismatch(ARGV[0]);
+			exit(0);
+		}
+		// the backend calls verify() on the raw volume before finalising it;
+		// 74 (EBADMSG) reports a rejected payload, the volume stays incomplete
+		let verify = (path) => ca_digest(ca.cmd, size, path) == ca.hash;
+		let ret = backend.write(ARGV[0], size, verify);
+		if (ret == 74)
+			ca_mismatch(ARGV[0]);
+		exit(ret);
+	}
+}
+
 if (type(backend[cmd]) == "function") {
 	let ret = backend[cmd](...ARGV);
 	if (type(ret) == "int") {

utils/uvol/files/uvol.defaults

@@ -1,21 +0,0 @@
-#!/bin/sh
-
-uvol_init() {
-	local metasz freesz totalsz
-	uvol detect
-	metasz="$(uvol size .meta 2>/dev/null)"
-	if [ "$metasz" ]; then
-		[ "$((metasz))" -gt 0 ] && return
-	fi
-	totalsz="$(uvol total)"
-	freesz="$(uvol free)"
-	metasz="$((totalsz / 10240))"
-	[ "$metasz" -lt 4194304 ] && metasz=4194304
-	[ "$metasz" -gt "$freesz" ] && return
-	uvol create .meta "$metasz" rw
-	uvol up .meta
-	grep -q "uvol/.meta" /proc/mounts || return
-	mkdir -p "/var/run/uvol/.meta/apk"
-}
-
-uci -q get fstab.@uvol[0].initialized >/dev/null || uvol_init

utils/uvol/files/uvol.init

@@ -6,16 +6,16 @@ NAME=uvol
 PROG=/usr/sbin/uvol
 
 start_service() {
-	[ "${__BOOT_UVOL}" = "1" ] && return 0
-	procd_open_instance "$NAME"
-	procd_set_param command "$PROG" boot
-	procd_close_instance
-}
+	local ready
 
-boot() {
-	__BOOT_UVOL=1 start
+	ready=$(ubus call block status 2>/dev/null | jsonfilter -e '@.ready')
+	[ "$ready" = "true" ] && "$PROG" boot
 }
 
 service_triggers() {
-	procd_add_raw_trigger "mount.ready" 200 /etc/init.d/uvol start
+	procd_add_raw_trigger "mount.ready" 1000 "$PROG" boot
+
+	# blockd emits mount.umount when an idle volume's device becomes free;
+	# reap any volume that was marked for deferred deletion while in use
+	procd_add_raw_trigger "mount.umount" 1000 "$PROG" reap
 }