[PATCH 3/4] populate: improve attr creation runtime

["Darrick J. Wong" <djwong@kernel.org>]

From: Darrick J. Wong <djwong@kernel.org>

Replace the file creation loops with a python script that does
everything we want from a single process.  This reduces the runtime of
_scratch_xfs_populate substantially by avoiding thousands of execve
overhead.  This patch builds on the previous one by reducing the runtime
of xfs/349 from ~45s to ~15s.

For people who don't have python3, use setfattr's "restore" mode to bulk
create xattrs.  This reduces runtime to about ~25s.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
 common/populate |   22 +++++++++++++++++---
 src/popattr.py  |   62 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 81 insertions(+), 3 deletions(-)
 create mode 100755 src/popattr.py


diff --git a/common/populate b/common/populate
index 180540aedd..f34551d272 100644
--- a/common/populate
+++ b/common/populate
@@ -12,6 +12,10 @@ _require_populate_commands() {
 	_require_xfs_io_command "fpunch"
 	_require_test_program "punch-alternating"
 	_require_test_program "popdir.pl"
+	if [ -n "${PYTHON3_PROG}" ]; then
+		_require_command $PYTHON3_PROG python3
+		_require_test_program "popattr.py"
+	fi
 	case "${FSTYP}" in
 	"xfs")
 		_require_command "$XFS_DB_PROG" "xfs_db"
@@ -108,9 +112,21 @@ __populate_create_attr() {
 	missing="$3"
 
 	touch "${name}"
-	seq 0 "${nr}" | while read d; do
-		setfattr -n "user.$(printf "%.08d" "$d")" -v "$(printf "%.08d" "$d")" "${name}"
-	done
+
+	if [ -n "${PYTHON3_PROG}" ]; then
+		${PYTHON3_PROG} $here/src/popattr.py --file "${name}" --end "${nr}"
+
+		test -z "${missing}" && return
+		${PYTHON3_PROG} $here/src/popattr.py --file "${name}" --start 1 --incr 2 --end "${nr}" --remove
+		return
+	fi
+
+	# Simulate a getfattr dump file so we can bulk-add attrs.
+	(
+		echo "# file: ${name}";
+		seq --format "user.%08g=\"abcdefgh\"" 0 "${nr}"
+		echo
+	) | setfattr --restore -
 
 	test -z "${missing}" && return
 	seq 1 2 "${nr}" | while read d; do
diff --git a/src/popattr.py b/src/popattr.py
new file mode 100755
index 0000000000..397ced9d33
--- /dev/null
+++ b/src/popattr.py
@@ -0,0 +1,62 @@
+#!/usr/bin/python3
+
+# Copyright (c) 2023 Oracle.  All rights reserved.
+# SPDX-License-Identifier: GPL-2.0
+#
+# Create a bunch of xattrs in a file.
+
+import argparse
+import sys
+import os
+
+parser = argparse.ArgumentParser(description = 'Mass create xattrs in a file')
+parser.add_argument(
+	'--file', required = True, type = str, help = 'manipulate this file')
+parser.add_argument(
+	'--start', type = int, default = 0,
+	help = 'create xattrs starting with this number')
+parser.add_argument(
+	'--incr', type = int, default = 1,
+	help = 'increment attr number by this much')
+parser.add_argument(
+	'--end', type = int, default = 1000,
+	help = 'stop at this attr number')
+parser.add_argument(
+	'--remove', dest = 'remove', action = 'store_true',
+	help = 'remove instead of creating')
+parser.add_argument(
+	'--format', type = str, default = '%08d',
+	help = 'printf formatting string for attr name')
+parser.add_argument(
+	'--verbose', dest = 'verbose', action = 'store_true',
+	help = 'verbose output')
+
+args = parser.parse_args()
+
+fmtstring = "user.%s" % args.format
+
+# If we are passed a regular file, open it as a proper file descriptor and
+# pass that around for speed.  Otherwise, we pass the path.
+fp = None
+try:
+	fp = open(args.file, 'r')
+	fd = fp.fileno()
+	os.listxattr(fd)
+	if args.verbose:
+		print("using fd calls")
+except:
+	if args.verbose:
+		print("using path calls")
+	fd = args.file
+
+for i in range(args.start, args.end + 1, args.incr):
+	fname = fmtstring % i
+
+	if args.remove:
+		if args.verbose:
+			print("removexattr %s" % fname)
+		os.removexattr(fd, fname)
+	else:
+		if args.verbose:
+			print("setxattr %s" % fname)
+		os.setxattr(fd, fname, b'abcdefgh')