xfstests: pwrite hang when writing from mmaped buffer of the same page

The problem is found in meego testing on btrfs:
http://bugs.meego.com/show_bug.cgi?id=6672

Signed-off-by: Zhong, Xin <xin.zhong@intel.com>
Reviewed-by: Hellwig, Christoph <hch@infradead.org>
Reviewed-by: Chinner, Dave <david@fromorbit.com>

248

@@ -0,0 +1,58 @@
+#! /bin/bash
+# FS QA Test No. 248
+#
+# Test for pwrite hang problem when writing from mmaped buffer of the same page 
+#
+#-----------------------------------------------------------------------
+#    Copyright (c) 2010 Intel Corporation
+#
+#    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; version 2 of the License
+#
+#    This program is distributed in the hope that it will 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 to the Free Software Foundation, Inc., 59
+#    Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+#
+#-----------------------------------------------------------------------
+#
+# creator
+owner=xin.zhong@intel.com
+
+seq=`basename $0`
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1	# failure is the default!
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+    cd /
+    rm -f $tmp.* $TESTFILE
+}
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+
+# real QA test starts here
+
+# Modify as appropriate.
+_supported_fs generic
+_supported_os Linux
+
+TESTFILE=$TEST_DIR/test_file
+TEST_PROG=$here/src/pwrite_mmap_blocked
+
+$TEST_PROG $TESTFILE
+
+# success, all done
+status=0
+exit

248.out

@@ -0,0 +1,2 @@
+QA output created by 248
+pwrite 1 bytes from 2 to 3

group

@@ -361,3 +361,4 @@ deprecated
 245 auto quick dir
 246 auto quick rw
 247 auto quick rw
+248 auto quick rw 

src/Makefile

@@ -17,7 +17,7 @@ LINUX_TARGETS = xfsctl bstat t_mtab getdevicesize preallo_rw_pattern_reader \
 	preallo_rw_pattern_writer ftrunc trunc fs_perms testx looptest \
 	locktest unwritten_mmap bulkstat_unlink_test t_stripealign \
 	bulkstat_unlink_test_modified t_dir_offset t_futimens t_immutable \
-	stale_handle
+	stale_handle pwrite_mmap_blocked
 
 SUBDIRS =
 

src/pwrite_mmap_blocked.c

@@ -0,0 +1,73 @@
+/*    Copyright (c) 2010 Intel Corporation
+ *
+ *    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; version 2 of the License
+ *
+ *    This program is distributed in the hope that it will 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 to the Free Software Foundation, Inc., 59
+ *    Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <time.h>
+#include <sys/mman.h>
+#include <sys/signal.h>
+#include <sys/stat.h>
+
+
+
+int main(int argc, char *argv[])
+{
+	int ret;
+	char *cc = "01234";
+	char *progname;
+	loff_t size;
+	loff_t amount = 1;
+	loff_t from = 2;
+	loff_t to = 3;
+	int fd;
+	void *mapped_mem;
+
+	progname = argv[0];
+	size = 5;
+	fd = open(argv[1], O_RDWR|O_TRUNC|O_CREAT, 0666);
+	if (fd < 0) {
+		fprintf(stderr, "%s: Cannot open `%s': %s\n",
+			progname, argv[1], strerror(errno));
+		exit(1);
+	}
+
+	if ((ret = pwrite(fd, (const char *)cc,
+				size, 0)) != size) {
+		perror("pwrite");
+		exit(1);
+	}
+
+	mapped_mem = mmap(0, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
+	if (mapped_mem == MAP_FAILED) {
+		perror("mmap");
+		exit(1);
+	}
+	printf("pwrite %Ld bytes from %Ld to %Ld\n", amount, from, to);
+
+	ret = pwrite(fd, (char *)mapped_mem + from, amount, to);
+	if (ret != amount) {
+		perror("pwrite");
+		exit(1);
+	}
+
+	munmap(mapped_mem,0);
+	close(fd);
+	exit(0);
+}