generic: add mmap write vs truncate/remap test

This test exposed a problem with mapped writes to the tail page of a
file in XFS and potentially ext4. Eric did all the hard work of
taking the bug report and generating the reproducable test case on
ext4.  Make it a generic test so that we can ensure that all
filesystems handle the case correctly.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

tests/generic/030

@@ -0,0 +1,148 @@
+#! /bin/bash
+# FS QA Test No. generic/030
+#
+# Test mapped writes against remap+truncate down/up to ensure we get the data
+# correctly written. This can expose data corruption bugs on filesystems where
+# the block size is smaller than the page size.
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2014 Red Hat, Inc.  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"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1	# failure is the default!
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+    cd /
+    rm -f $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+
+# real QA test starts here
+
+# Modify as appropriate.
+_supported_fs generic
+_supported_os IRIX Linux
+_require_scratch
+_require_xfs_io_command "mremap"
+
+testfile=$SCRATCH_MNT/testfile
+
+_scratch_mkfs > /dev/null 2>&1
+_scratch_mount
+
+# first case is just truncate down/truncate up to check that the mapped
+# write after the truncate up is correctly handled.
+$XFS_IO_PROG -t -f \
+-c "truncate 5017k"             `# truncate     |       |` \
+-c "pwrite -S 0x58 0 5017k"     `# write        |X...XXX|` \
+-c "mmap -rw 0 5017k"           `# mmap         |       |` \
+-c "truncate 5020k"             `# truncate up  |                        |` \
+-c "mremap -m 5020k"            `# mremap up    |                        |` \
+-c "mwrite -S 0x57 5017k 3k"    `# mwrite       |        WWWWWWWWWWWWWWWW|` \
+-c "mremap 5017k "              `# mremap dn    |       |` \
+-c "truncate 5017k"             `# mremap dn    |       |` \
+-c "truncate 5020k"             `# truncate up  |                        |` \
+-c "mremap -m 5020k"            `# mremap up    |                        |` \
+-c "mwrite -S 0x59 5017k 3k"    `# mwrite       |        YYYYYYYYYYYYYYYY|` \
+-c "close"      \
+$testfile | _filter_xfs_io
+
+echo "==== Pre-Remount ==="
+hexdump -C $testfile
+_scratch_remount
+echo "==== Post-Remount =="
+hexdump -C $testfile
+
+rm -f $testfile
+sync
+
+# second case is to do a mwrite between the truncate to a block on the
+# same page we are truncating within the EOF. This checks that a mapped
+# write between truncate down and truncate up a further mapped
+# write to the same page into the new space doesn't result in data being lost.
+$XFS_IO_PROG -t -f \
+-c "truncate 5017k"             `# truncate     |       |` \
+-c "pwrite -S 0x58 0 5017k"     `# write        |X...XXX|` \
+-c "mmap -rw 0 5017k"           `# mmap         |       |` \
+-c "truncate 5020k"             `# truncate up  |                        |` \
+-c "mremap -m 5020k"            `# mremap up    |                        |` \
+-c "mwrite -S 0x57 5017k 3k"    `# mwrite       |        WWWWWWWWWWWWWWWW|` \
+-c "mremap 5017k "              `# mremap dn    |       |` \
+-c "truncate 5017k"             `# mremap dn    |       |` \
+-c "mwrite -S 0x5a 5016k 1k"    `# mwrite       |    ZZZ                 |` \
+-c "truncate 5020k"             `# truncate up  |                        |` \
+-c "mremap -m 5020k"            `# mremap up    |                        |` \
+-c "mwrite -S 0x59 5017k 3k"    `# mwrite       |        YYYYYYYYYYYYYYYY|` \
+-c "close"      \
+$testfile | _filter_xfs_io
+
+echo "==== Pre-Remount ==="
+hexdump -C $testfile
+_scratch_remount
+echo "==== Post-Remount =="
+hexdump -C $testfile
+
+# third case is the same as the first, but this time on unaligned byte
+# boundaries rather than block boundaries. This mimics the exact mmap write
+# patterns of the application that exposed the bug in the first place, and
+# so is somewhat more complex and has repeated operations in it. 
+$XFS_IO_PROG -t -f \
+-c "truncate 5136912" \
+-c "pwrite -S 0x58 0 5136912" \
+-c "mmap -rw 0 5136912" \
+-c "mremap 5136912" \
+-c "truncate 5136912" \
+-c "truncate 5139720" \
+-c "mremap -m 5139720" \
+-c "mwrite -S 0 5136912 2808" \
+-c "mwrite -S 0 5136912 2808" \
+-c "mwrite -S 0 5136912 2808" \
+-c "mremap 5136912 " \
+-c "truncate 5136912" \
+-c "truncate 5139720" \
+-c "mremap -m 5139720" \
+-c "mwrite -S 0 5136912 2808" \
+-c "mwrite -S 0 5136912 2808" \
+-c "mwrite -S 0x59 5136912 2808" \
+-c "truncate 5140480" \
+-c "mremap 5140480" \
+-c "msync -s 0 5140480" \
+-c "mremap 5139720" \
+-c "munmap" \
+-c "close" \
+$testfile | _filter_xfs_io
+
+echo "==== Pre-Remount ==="
+hexdump -C $testfile
+_scratch_remount
+echo "==== Post-Remount =="
+hexdump -C $testfile
+
+status=0
+exit
+

tests/generic/030.out

@@ -0,0 +1,53 @@
+QA output created by 030
+wrote 5137408/5137408 bytes at offset 0
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+==== Pre-Remount ===
+00000000  58 58 58 58 58 58 58 58  58 58 58 58 58 58 58 58  |XXXXXXXXXXXXXXXX|
+*
+004e6400  59 59 59 59 59 59 59 59  59 59 59 59 59 59 59 59  |YYYYYYYYYYYYYYYY|
+*
+004e7000
+==== Post-Remount ==
+00000000  58 58 58 58 58 58 58 58  58 58 58 58 58 58 58 58  |XXXXXXXXXXXXXXXX|
+*
+004e6400  59 59 59 59 59 59 59 59  59 59 59 59 59 59 59 59  |YYYYYYYYYYYYYYYY|
+*
+004e7000
+wrote 5137408/5137408 bytes at offset 0
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+==== Pre-Remount ===
+00000000  58 58 58 58 58 58 58 58  58 58 58 58 58 58 58 58  |XXXXXXXXXXXXXXXX|
+*
+004e6000  5a 5a 5a 5a 5a 5a 5a 5a  5a 5a 5a 5a 5a 5a 5a 5a  |ZZZZZZZZZZZZZZZZ|
+*
+004e6400  59 59 59 59 59 59 59 59  59 59 59 59 59 59 59 59  |YYYYYYYYYYYYYYYY|
+*
+004e7000
+==== Post-Remount ==
+00000000  58 58 58 58 58 58 58 58  58 58 58 58 58 58 58 58  |XXXXXXXXXXXXXXXX|
+*
+004e6000  5a 5a 5a 5a 5a 5a 5a 5a  5a 5a 5a 5a 5a 5a 5a 5a  |ZZZZZZZZZZZZZZZZ|
+*
+004e6400  59 59 59 59 59 59 59 59  59 59 59 59 59 59 59 59  |YYYYYYYYYYYYYYYY|
+*
+004e7000
+wrote 5136912/5136912 bytes at offset 0
+XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+==== Pre-Remount ===
+00000000  58 58 58 58 58 58 58 58  58 58 58 58 58 58 58 58  |XXXXXXXXXXXXXXXX|
+*
+004e6210  59 59 59 59 59 59 59 59  59 59 59 59 59 59 59 59  |YYYYYYYYYYYYYYYY|
+*
+004e6d00  59 59 59 59 59 59 59 59  00 00 00 00 00 00 00 00  |YYYYYYYY........|
+004e6d10  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
+*
+004e7000
+==== Post-Remount ==
+00000000  58 58 58 58 58 58 58 58  58 58 58 58 58 58 58 58  |XXXXXXXXXXXXXXXX|
+*
+004e6210  59 59 59 59 59 59 59 59  59 59 59 59 59 59 59 59  |YYYYYYYYYYYYYYYY|
+*
+004e6d00  59 59 59 59 59 59 59 59  00 00 00 00 00 00 00 00  |YYYYYYYY........|
+004e6d10  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
+*
+004e7000

tests/generic/group

@@ -32,6 +32,7 @@
 027 auto enospc
 028 auto quick
 029 auto quick rw
+030 auto quick rw
 053 acl repair auto quick
 062 attr udf auto quick
 068 other auto freeze dangerous stress