generic: test XATTR_REPLACE doesn't take the fs down

Kanda Motohiro reported that expanding a tiny xattr into a large
xattr fails on XFS because we remove the tiny xattr from a shortform
fork and then try to re-add it after converting the fork to extents
format having not removed the ATTR_REPLACE flag.  This fails because
the attr is no longer present, causing a fs shutdown.

[Eryu: introduce function "fail" and use it where appropriate]

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=199119
Reported-by: kanda.motohiro@gmail.com
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>

.gitignore

@@ -52,6 +52,7 @@
 /src/alloc
 /src/append_reader
 /src/append_writer
+/src/attr_replace_test
 /src/attr-list-by-handle-cursor-test
 /src/bstat
 /src/bulkstat_unlink_test

src/Makefile

@@ -25,7 +25,8 @@ LINUX_TARGETS = xfsctl bstat t_mtab getdevicesize preallo_rw_pattern_reader \
 	seek_copy_test t_readdir_1 t_readdir_2 fsync-tester nsexec cloner \
 	renameat2 t_getcwd e4compact test-nextquota punch-alternating \
 	attr-list-by-handle-cursor-test listxattr dio-interleaved t_dir_type \
-	dio-invalidate-cache stat_test t_encrypted_d_revalidate
+	dio-invalidate-cache stat_test t_encrypted_d_revalidate \
+	attr_replace_test
 
 SUBDIRS = log-writes perf
 

src/attr_replace_test.c

@@ -0,0 +1,67 @@
+// setattr.c by kanda.motohiro@gmail.com
+// xfs extended attribute corruption bug reproducer
+#include <stdio.h>
+#include <string.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/xattr.h>
+#include <sys/stat.h>
+
+#define die() do { perror(""); \
+fprintf(stderr, "error=%d at line %d\n", errno, __LINE__); \
+exit(1); } while (0)
+
+#define fail(...) do { \
+fprintf(stderr, __VA_ARGS__); exit (1); \
+} while (0)
+
+int main(int argc, char *argv[])
+{
+	int ret;
+	int fd;
+	char *path;
+	char *name = "user.world";
+	char *value;
+	struct stat sbuf;
+	size_t size = sizeof(value);
+
+	if (argc != 2)
+		fail("Usage: %s <file>\n", argv[0]);
+	path = argv[1];
+
+	fd = open(path, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR);
+	if (fd < 0) die();
+
+	/*
+	 * The value should be 3/4 the size of a fs block to ensure that we
+	 * get to extents format.
+	 */
+	ret = fstat(fd, &sbuf);
+	if (ret < 0) die();
+	size = sbuf.st_blksize * 3 / 4;
+	if (!size)
+		fail("Invalid st_blksize(%ld)\n", sbuf.st_blksize);
+	value = malloc(size);
+	if (!value)
+		fail("Failed to allocate memory\n");
+
+	/* First, create a small xattr. */
+	memset(value, '0', 1);
+	ret = fsetxattr(fd, name, value, 1, XATTR_CREATE);
+	if (ret < 0) die();
+	close(fd);
+
+	fd = open(path, O_RDWR);
+	if (fd < 0) die();
+
+	/* Then, replace it with bigger one, forcing short form to leaf conversion. */
+	memset(value, '1', size);
+	ret = fsetxattr(fd, name, value, size, XATTR_REPLACE);
+	if (ret < 0) die();
+	close(fd);
+
+	return 0;
+}

tests/generic/486

@@ -0,0 +1,71 @@
+#! /bin/bash
+# FS QA Test No. 486
+#
+# Ensure that we can XATTR_REPLACE a tiny attr into a large attr.
+# Kanda Motohiro <kanda.motohiro@gmail.com> reports that XATTR_REPLACE'ing
+# a single-byte attr with a 2048-byte attr causes a fs shutdown because we
+# remove the shortform attr, convert the attr fork to long format, and then
+# try to re-add the attr having not cleared ATTR_REPLACE.
+#
+# Commit 7b38460dc8e4 ("xfs: don't fail when converting shortform attr to long
+# form during ATTR_REPLACE") fixed the xfs bug.
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2018 Oracle.  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  02110-1301  USA
+#
+#-----------------------------------------------------------------------
+
+seq=`basename $0`
+seqres=$RESULT_DIR/$seq
+echo "QA output created by $seq"
+
+status=1	# failure is the default!
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+	cd /
+	rm -f $testfile
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+. ./common/attr
+
+# remove previous $seqres.full before test
+rm -f $seqres.full
+
+# real QA test starts here
+_supported_fs generic
+_supported_os Linux
+_require_test_program "attr_replace_test"
+_require_attrs
+_require_scratch
+
+rm -f $seqres.full
+_scratch_mkfs >>$seqres.full 2>&1
+_scratch_mount >>$seqres.full 2>&1
+
+filter_attr_output() {
+	_filter_scratch | sed -e 's/has a [0-9]* byte value/has a NNNN byte value/g'
+}
+
+./src/attr_replace_test $SCRATCH_MNT/hello
+$ATTR_PROG -l $SCRATCH_MNT/hello | filter_attr_output
+
+status=0
+exit

tests/generic/486.out

@@ -0,0 +1,2 @@
+QA output created by 486
+Attribute "world" has a NNNN byte value for SCRATCH_MNT/hello

tests/generic/group

@@ -488,3 +488,4 @@
 483 auto quick log metadata
 484 auto quick
 485 auto quick insert
+486 auto quick attr