[7/7] xfs_property: add a new tool to administer fs properties

Commit Message

Darrick J. Wong Aug. 6, 2024, 6:21 p.m. UTC

From: Darrick J. Wong <[e-mail]>

Create a tool to list, get, set, and remove filesystem properties.

Signed-off-by: Darrick J. Wong <[e-mail]>Acked-by: Dave Chinner <[e-mail]>
---
 io/Makefile             |    3 +-
 io/xfs_property         |   77 +++++++++++++++++++++++++++++++++++++++++++++++
 man/man8/xfs_property.8 |   61 +++++++++++++++++++++++++++++++++++++
 3 files changed, 140 insertions(+), 1 deletion(-)
 create mode 100755 io/xfs_property
 create mode 100644 man/man8/xfs_property.8

Comments

Christoph Hellwig Aug. 7, 2024, 4:10 p.m. UTC | #1

Looks good:

Reviewed-by: Christoph Hellwig <[e-mail]>

Patch

diff --git a/io/Makefile b/io/Makefile
index 0bdd05b57..c33d57f5e 100644
--- a/io/Makefile
+++ b/io/Makefile
@@ -6,7 +6,7 @@  TOPDIR = ..
 include $(TOPDIR)/include/builddefs
 
 LTCOMMAND = xfs_io
-LSRCFILES = xfs_bmap.sh xfs_freeze.sh xfs_mkfile.sh
+LSRCFILES = xfs_bmap.sh xfs_freeze.sh xfs_mkfile.sh xfs_property
 HFILES = init.h io.h
 CFILES = \
 	attr.c \
@@ -92,6 +92,7 @@  install: default
 	$(LTINSTALL) -m 755 xfs_bmap.sh $(PKG_SBIN_DIR)/xfs_bmap
 	$(LTINSTALL) -m 755 xfs_freeze.sh $(PKG_SBIN_DIR)/xfs_freeze
 	$(LTINSTALL) -m 755 xfs_mkfile.sh $(PKG_SBIN_DIR)/xfs_mkfile
+	$(LTINSTALL) -m 755 xfs_property $(PKG_SBIN_DIR)/xfs_property
 install-dev:
 
 -include .dep
diff --git a/io/xfs_property b/io/xfs_property
new file mode 100755
index 000000000..6f630312a
--- /dev/null
+++ b/io/xfs_property
@@ -0,0 +1,77 @@ 
+#!/bin/bash -f
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright (c) 2024 Oracle.  All Rights Reserved.
+# Author: Darrick J. Wong <[e-mail]>
+#
+
+OPTS=""
+USAGE="Usage: xfs_property [-V] [mountpoint|device|file] [list [-v]|get name...|set name=value...|remove name...]"
+
+# Try to find a loop device associated with a file.  We only want to return
+# one loopdev (multiple loop devices can attach to a single file) so we grab
+# the last line and return it if it's actually a block device.
+try_find_loop_dev_for_file() {
+	local x="$(losetup -O NAME -j "$1" 2> /dev/null | tail -n 1)"
+	test -b "${x}" && echo "${x}"
+}
+
+while getopts "V" c
+do
+	case $c in
+	V)	xfs_io -p xfs_info -V
+		status=$?
+		exit ${status}
+		;;
+	*)	echo "${USAGE}" 1>&2
+		exit 2
+		;;
+	esac
+done
+set -- extra "$@"
+shift $OPTIND
+
+if [ $# -lt 2 ]; then
+	echo "${USAGE}" 1>&2
+	exit 2
+fi
+
+target="$1"
+shift
+subcommand="$1"
+shift
+
+db_args=()
+io_args=()
+
+case "$subcommand" in
+"list")
+	vparam=
+	if [ $# -eq 1 ] && [ "$1" = "-v" ]; then
+		vparam=" -v"
+	fi
+	db_args+=('-c' "attr_list -Z${vparam}")
+	io_args+=('-c' "listfsprops${vparam}")
+	;;
+"get"|"remove"|"set")
+	for arg in "$@"; do
+		db_args+=('-c' "attr_${subcommand} -Z ${arg/=/ }")
+		io_args+=('-c' "${subcommand}fsprops ${arg}")
+	done
+	;;
+*)
+	echo "${USAGE}" 1>&2
+	exit 2
+esac
+
+# See if we can map the arg to a loop device
+loopdev="$(try_find_loop_dev_for_file "${target}")"
+test -n "${loopdev}" && target="${loopdev}"
+
+# If we find a mountpoint for the device, do a live query; otherwise try
+# reading the fs with xfs_db.
+if mountpt="$(findmnt -t xfs -f -n -o TARGET "${target}" 2> /dev/null)"; then
+	exec xfs_io -p xfs_property "${io_args[@]}" "${mountpt}"
+else
+	exec xfs_db -p xfs_property -x -c 'path /' "${db_args[@]}" "${target}"
+fi
diff --git a/man/man8/xfs_property.8 b/man/man8/xfs_property.8
new file mode 100644
index 000000000..19c1c0e37
--- /dev/null
+++ b/man/man8/xfs_property.8
@@ -0,0 +1,61 @@ 
+.TH xfs_property 8
+.SH NAME
+xfs_property \- examine and edit properties about an XFS filesystem
+.SH SYNOPSIS
+.B xfs_property
+.I target
+.B get
+.IR name ...
+.br
+.B xfs_property
+.I target
+.B list [ \-v ]
+.br
+.B xfs_property
+.I target
+.B set
+.IR name=value ...
+.br
+.B xfs_property
+.I target
+.B remove
+.IR name ...
+.br
+.B xfs_property \-V
+.SH DESCRIPTION
+.B xfs_property
+retrieves, lists, sets, or removes properties of an XFS filesystem.
+Filesystem properties are root-controlled attributes set on the root directory
+of the filesystem to enable the system administrator to coordinate with
+userspace programs.
+
+.I target
+is one of: the root directory of a mounted filesystem; a block device containing
+an XFS filesystem; or a regular file containing an XFS filesystem.
+
+.SH OPTIONS
+.TP
+.B \-V
+Print the version number and exits.
+
+.SH COMMANDS
+.TP
+.B get
+.IR name ...
+Prints the values of the given filesystem properties.
+.TP
+.B list
+Lists the names of all filesystem properties.
+If the
+.B -v
+flag is specified, prints the values as well.
+.TP
+.B set
+.IR name = value ...
+Sets the given filesystem properties to the specified values and prints what
+was set.
+.TP
+.B
+remove
+.IR name ...
+Unsets the given filesystem properties.