[PATCH v2 2/4] btrfs/124: test global metadata reservation reporting

[jeffm@suse.com]

From: Jeff Mahoney <jeffm@suse.com>

Btrfs can now report the size of the global metadata reservation
via ioctl and sysfs.

This test confirms that we get sane results on an empty file system.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
---
 .gitignore               |   1 +
 common/btrfs             |  43 +++++++++++++++
 src/Makefile             |   3 +-
 src/btrfs_ioctl_helper.c | 132 +++++++++++++++++++++++++++++++++++++++++++++++
 tests/btrfs/124          |  84 ++++++++++++++++++++++++++++++
 tests/btrfs/124.out      |   1 +
 tests/btrfs/group        |   1 +
 7 files changed, 264 insertions(+), 1 deletion(-)
 create mode 100644 common/btrfs
 create mode 100644 src/btrfs_ioctl_helper.c
 create mode 100755 tests/btrfs/124
 create mode 100644 tests/btrfs/124.out

diff --git a/.gitignore b/.gitignore
index 28bd180..0e4f2a1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -39,6 +39,7 @@
 /src/append_reader
 /src/append_writer
 /src/bstat
+/src/btrfs_ioctl_helper
 /src/bulkstat_unlink_test
 /src/bulkstat_unlink_test_modified
 /src/dbtest
diff --git a/common/btrfs b/common/btrfs
new file mode 100644
index 0000000..b972b13
--- /dev/null
+++ b/common/btrfs
@@ -0,0 +1,43 @@
+#!/bin/bash
+# Functions for testing btrfs
+
+_btrfs_get_fsid()
+{
+	local mnt=$1
+	if [ -z "$mnt" ]; then
+		mnt=$TEST_DIR
+	fi
+	$BTRFS_UTIL_PROG filesystem show $mnt|awk '/uuid:/ {print $NF}'
+}
+
+_btrfs_get_sysfs()
+{
+	local mnt=$1
+	local fsid=$(_btrfs_get_fsid $mnt)
+	echo "/sys/fs/btrfs/$fsid"
+}
+
+_require_btrfs_sysfs()
+{
+	local mnt=$1
+	if [ -z "$mnt" ]; then
+		mnt=$TEST_DIR
+	fi
+	if [ ! -d "$(_btrfs_get_sysfs $mnt)" ];then
+		_notrun "btrfs sysfs support not available."
+	fi
+}
+
+_require_btrfs_ioctl()
+{
+	local ioctl=$1
+	local mnt=$2
+	shift 2
+	if [ -z "$mnt" ]; then
+		mnt=$TEST_DIR
+	fi
+	out=$(src/btrfs_ioctl_helper $mnt $ioctl $@)
+	if [ "$out" = "Not implemented." ]; then
+		_notrun "btrfs ioctl $ioctl not implemented."
+	fi
+}
diff --git a/src/Makefile b/src/Makefile
index 1bf318b..c467475 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -20,7 +20,8 @@ LINUX_TARGETS = xfsctl bstat t_mtab getdevicesize preallo_rw_pattern_reader \
 	bulkstat_unlink_test_modified t_dir_offset t_futimens t_immutable \
 	stale_handle pwrite_mmap_blocked t_dir_offset2 seek_sanity_test \
 	seek_copy_test t_readdir_1 t_readdir_2 fsync-tester nsexec cloner \
-	renameat2 t_getcwd e4compact test-nextquota punch-alternating
+	renameat2 t_getcwd e4compact test-nextquota punch-alternating \
+	btrfs_ioctl_helper
 
 SUBDIRS =
 
diff --git a/src/btrfs_ioctl_helper.c b/src/btrfs_ioctl_helper.c
new file mode 100644
index 0000000..b6eb924
--- /dev/null
+++ b/src/btrfs_ioctl_helper.c
@@ -0,0 +1,132 @@
+#include <sys/ioctl.h>
+#include <stdio.h>
+#include <sys/fcntl.h>
+#include <errno.h>
+#include <string.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+#ifndef BTRFS_IOCTL_MAGIC
+#define BTRFS_IOCTL_MAGIC 0x94
+#endif
+
+#ifndef BTRFS_IOC_SPACE_INFO
+struct btrfs_ioctl_space_info {
+        uint64_t flags;
+        uint64_t total_bytes;
+        uint64_t used_bytes;
+};
+
+struct btrfs_ioctl_space_args {
+        uint64_t space_slots;
+        uint64_t total_spaces;
+        struct btrfs_ioctl_space_info spaces[0];
+};
+#define BTRFS_IOC_SPACE_INFO _IOWR(BTRFS_IOCTL_MAGIC, 20, \
+                                    struct btrfs_ioctl_space_args)
+#endif
+#ifndef BTRFS_SPACE_INFO_GLOBAL_RSV
+#define BTRFS_SPACE_INFO_GLOBAL_RSV    (1ULL << 49)
+#endif
+
+static int global_rsv_ioctl(int fd, int argc, char *argv[])
+{
+	struct btrfs_ioctl_space_args arg;
+	struct btrfs_ioctl_space_args *args;
+	int ret;
+	int i;
+	size_t size;
+
+	arg.space_slots = 0;
+
+	ret = ioctl(fd, BTRFS_IOC_SPACE_INFO, &arg);
+	if (ret)
+		return -errno;
+
+	size = sizeof(*args) + sizeof(args->spaces[0]) * arg.total_spaces;
+	args = malloc(size);
+	if (!args)
+		return -ENOMEM;
+
+	args->space_slots = arg.total_spaces;
+
+	ret = ioctl(fd, BTRFS_IOC_SPACE_INFO, args);
+	if (ret)
+		return -errno;
+
+	for (i = 0; i < args->total_spaces; i++) {
+		if (args->spaces[i].flags & BTRFS_SPACE_INFO_GLOBAL_RSV) {
+			unsigned long long reserved;
+			reserved = args->spaces[i].total_bytes;
+			printf("%llu\n", reserved);
+			return 0;
+		}
+	}
+
+	return -ENOENT;
+}
+
+#define IOCTL_TABLE_ENTRY(_ioctl_name, _handler) \
+	{ .name = #_ioctl_name, .ioctl_cmd = BTRFS_IOC_##_ioctl_name, \
+	  .handler = _handler, }
+
+struct ioctl_table_entry {
+	const char *name;
+	unsigned ioctl_cmd;
+	int (*handler)(int fd, int argc, char *argv[]);
+};
+
+static struct ioctl_table_entry ioctls[] = {
+	IOCTL_TABLE_ENTRY(SPACE_INFO, global_rsv_ioctl),
+};
+
+int
+main(int argc, char *argv[])
+{
+	int fd;
+	int ret;
+	struct ioctl_table_entry *entry = NULL;
+	int i;
+
+	if (argc < 3) {
+		fprintf(stderr,
+			"usage: %s <fs mount point> <ioctl name> [args..]\n",
+			argv[0]);
+		return 1;
+	}
+
+	fd = open(argv[1], O_RDONLY|O_DIRECTORY);
+	if (fd < 0) {
+		perror(argv[1]);
+		return 1;
+	}
+
+	for (i = 0; i < (sizeof(ioctls)/sizeof(ioctls[0])); i++) {
+		if (strcmp(argv[2], ioctls[i].name) == 0) {
+			entry = &ioctls[i];
+			break;
+		}
+	}
+
+	if (!entry) {
+		fprintf(stderr, "ERROR: unknown ioctl %s\n", argv[2]);
+		close(fd);
+		return 1;
+	}
+
+	ret = entry->handler(fd, argc - 3, argv + 3);
+	if (ret == -ENOTTY) {
+		printf("Not implemented.\n");
+		close(fd);
+		return 0;
+	} else if (ret) {
+		fprintf(stderr, "ERROR: %s failed: %s\n",
+			entry->name, strerror(-ret));
+		close(fd);
+		return 1;
+	}
+
+	close(fd);
+	return 0;
+}
diff --git a/tests/btrfs/124 b/tests/btrfs/124
new file mode 100755
index 0000000..2ab9dfb
--- /dev/null
+++ b/tests/btrfs/124
@@ -0,0 +1,84 @@
+#!/bin/bash
+# FA QA Test No. 124
+#
+# Test global metadata reservation reporting
+#
+# 1) Create empty file system
+# 2) Call the BTRFS_IOC_GLOBAL_RSV ioctl
+# 3) Read the /sys/fs/btrfs/<fsid>/allocation/global_rsv_reserved file
+#    and confirm it's a number
+# 4) Compare the results between the two to confirm they match
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2016 SUSE, All Rights Reserved.
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it would be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write the Free Software Foundation,
+# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  12110-1301  USA
+#-----------------------------------------------------------------------
+
+seq=$(basename $0)
+seqres=$RESULT_DIR/$seq
+echo "QA output created by $seq"
+
+here=$(pwd)
+tmp=/tmp/$$
+status=1
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+	cd /
+	rm -f $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/btrfs
+. ./common/filter.btrfs
+
+# remove previous $seqres.full before test
+rm -f $seqres.full
+
+_supported_fs btrfs
+_supported_os Linux
+_require_test
+_require_btrfs_ioctl SPACE_INFO
+_require_btrfs_sysfs
+
+IOCTL="src/btrfs_ioctl_helper"
+
+SYSFS_PREFIX="$(_btrfs_get_sysfs)/allocation"
+[ -d "$SYSFS_PREFIX" ] || _notrun "sysfs directory not found"
+
+check_sysfs_output()
+{
+	reserved="$1"
+	method="$2"
+	if [ -n "$(echo $reserved | tr -d 0-9)" ]; then
+		echo "$method: numerical value expected (got $reserved)"
+	fi
+}
+
+ioctl_reserved="$($IOCTL $TEST_DIR SPACE_INFO)"
+
+reserved="$(cat $SYSFS_PREFIX/global_rsv_reserved)"
+check_sysfs_output "$reserved" "sysfs:reserved"
+if [ "$reserved" != "$ioctl_reserved" ]; then
+	echo "ioctl ($ioctl_reserved) != sysfs ($reserved)"
+fi
+size="$(cat $SYSFS_PREFIX/global_rsv_size)"
+check_sysfs_output "$size" "sysfs:size"
+
+# success, all done
+status=0
+exit
diff --git a/tests/btrfs/124.out b/tests/btrfs/124.out
new file mode 100644
index 0000000..0129e81
--- /dev/null
+++ b/tests/btrfs/124.out
@@ -0,0 +1 @@
+QA output created by 124
diff --git a/tests/btrfs/group b/tests/btrfs/group
index 5a26ed7..8b5050e 100644
--- a/tests/btrfs/group
+++ b/tests/btrfs/group
@@ -126,3 +126,4 @@
 121 auto quick snapshot qgroup
 122 auto quick snapshot qgroup
 123 auto quick qgroup
+124 auto quick metadata
-- 
1.8.5.6