btrfs-progs: qgroup show: fix formatting of limit values in json output

There are reports that json output of 'qgroup show' crashes due to
internal error when printing the limit values:

  INTERNAL ERROR: unknown unit base, mode 2304
  btrfs(internal_error+0x10a)[0x5605c37ce48a]
  btrfs(pretty_size_snprintf+0x5c)[0x5605c37d105c]
  btrfs(fmt_print+0x44e)[0x5605c37d178e]
  btrfs(+0x7ed1d)[0x5605c3800d1d]
  btrfs(main+0x8f)[0x5605c379beff]
  /lib64/libc.so.6(+0x27bb0)[0x7f83924ddbb0]
  /lib64/libc.so.6(__libc_start_main+0x8b)[0x7f83924ddc79]
  btrfs(_start+0x25)[0x5605c379d405]
  common/units.c:82: pretty_size_snprintf: Assertion `0` failed, value 0
  btrfs(+0x1d4b1)[0x5605c379f4b1]
  btrfs(pretty_size_snprintf+0x7b)[0x5605c37d107b]
  btrfs(fmt_print+0x44e)[0x5605c37d178e]
  btrfs(+0x7ed1d)[0x5605c3800d1d]
  btrfs(main+0x8f)[0x5605c379beff]
  /lib64/libc.so.6(+0x27bb0)[0x7f83924ddbb0]
  /lib64/libc.so.6(__libc_start_main+0x8b)[0x7f83924ddc79]
  btrfs(_start+0x25)[0x5605c379d405]

This is caused by "size" format that requires the unit mode, but it was not
specified and some stack value used. As json prints the raw values, use
the plain %llu format.

Link: https://bugzilla.opensuse.org/show_bug.cgi?id=1206960
Link: https://bugzilla.opensuse.org/show_bug.cgi?id=1209136#c15
Signed-off-by: David Sterba <dsterba@suse.com>

Author: kdave

cmds/qgroup.c

@@ -1439,10 +1439,10 @@ static const struct rowspec qgroup_show_rowspec[] = {
 	{ .key = "qgroupid", .fmt = "qgroupid", .out_json = "qgroupid" },
 	{ .key = "referenced", .fmt = "%llu", .out_json = "referenced" },
 	{ .key = "exclusive", .fmt = "%llu", .out_json = "exclusive" },
-	{ .key = "max_referenced", .fmt = "size", .out_json = "max_referenced" },
+	{ .key = "max_referenced", .fmt = "%llu", .out_json = "max_referenced" },
 	/* Special value if limits not set. */
 	{ .key = "max_referenced-none", .fmt = "%s", .out_json = "max_referenced" },
-	{ .key = "max_exclusive", .fmt = "size", .out_json = "max_exclusive" },
+	{ .key = "max_exclusive", .fmt = "%llu", .out_json = "max_exclusive" },
 	/* Special value if limits not set. */
 	{ .key = "max_exclusive-none", .fmt = "%s", .out_json = "max_exclusive" },
 	{ .key = "path", .fmt = "str", .out_json = "path" },

tests/cli-tests/005-qgroup-show/test.sh

@@ -17,6 +17,7 @@ run_mayfail "$TOP/btrfs" --format json qgroup show "$TEST_MNT"
 run_mayfail $SUDO_HELPER "$TOP/btrfs" qgroup show "$TEST_MNT"
 run_mayfail $SUDO_HELPER "$TOP/btrfs" --format json qgroup show "$TEST_MNT"
 run_check $SUDO_HELPER "$TOP/btrfs" quota enable "$TEST_MNT"
+run_check $SUDO_HELPER "$TOP/btrfs" qgroup limit 128m "$TEST_MNT"
 run_mayfail "$TOP/btrfs" qgroup show "$TEST_MNT"
 run_mayfail "$TOP/btrfs" --format json qgroup show "$TEST_MNT"
 run_check $SUDO_HELPER "$TOP/btrfs" qgroup show "$TEST_MNT"