We met a kernel assertion failure recently as below:
XFS: Assertion failed: tp->t_blk_res_used <= tp->t_blk_res, file: fs/xfs/xfs_trans.c, line: 309
The problem comes when the several IO vectors are copied in, and
it runs into page faults.
Signed-off-by: Zorro Lang <zlang@xxxxxxxxxx>
---
Hi,
Although I'm trying to add writev/readv test to fsstress, and it has tiny
chance to cover this bug (very hard to reproduce). But I still think using
a special case to cover this part is better.
Thanks,
Zorro
.gitignore | 1 +
src/Makefile | 2 +-
src/writev_on_pagefault.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++
tests/generic/441 | 61 ++++++++++++++++++++++++++++++++++++++
tests/generic/441.out | 2 ++
tests/generic/group | 1 +
6 files changed, 140 insertions(+), 1 deletion(-)
create mode 100644 src/writev_on_pagefault.c
create mode 100755 tests/generic/441
create mode 100644 tests/generic/441.out
diff --git a/.gitignore b/.gitignore
index 39664b0..043e87f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -130,6 +130,7 @@
/src/unwritten_sync
/src/usemem
/src/writemod
+/src/writev_on_pagefault
/src/xfsctl
/src/aio-dio-regress/aio-dio-extend-stat
/src/aio-dio-regress/aio-dio-fcntl-race
diff --git a/src/Makefile b/src/Makefile
index 6b0e4b0..9d54fe7 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -9,7 +9,7 @@ TARGETS = dirstress fill fill2 getpagesize holes lstat64 \
nametest permname randholes runas truncfile usemem \
mmapcat append_reader append_writer dirperf metaperf \
devzero feature alloc fault fstest t_access_root \
- godown resvtest writemod makeextents itrash rename \
+ godown resvtest writemod writev_on_pagefault makeextents itrash rename \
multi_open_unlink dmiperf unwritten_sync genhashnames t_holes \
t_mmap_writev t_truncate_cmtime dirhash_collide t_rename_overwrite \
holetest t_truncate_self t_mmap_dio af_unix t_mmap_stale_pmd \
diff --git a/src/writev_on_pagefault.c b/src/writev_on_pagefault.c
new file mode 100644
index 0000000..54845c3
--- /dev/null
+++ b/src/writev_on_pagefault.c
@@ -0,0 +1,74 @@
+/*
+ * Takes page fault while writev is iterating over the vectors in the IOV
+ *
+ * Copyright (C) 2017 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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 <stdlib.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/uio.h>
+
+#define IOV_CNT 3
+
+void
+usage(char *progname)
+{
+ fprintf(stderr, "usage: %s filename\n", progname);
+ exit(1);
+}
+
+int main(int argc, char *argv[])
+{
+ int fd, i;
+ size_t ret;
+ struct iovec *iov;
+ int pagesz = 4096;
+ char *data = NULL;
+
+ if (argc != 2)
+ usage(argv[0]);
+
+ pagesz = getpagesize();
+ data = malloc(pagesz * IOV_CNT);
+
+ /* no pre-writing on the buffer before writev */
+
+ iov = calloc(IOV_CNT, sizeof(struct iovec));
+ for (i = 0; i < IOV_CNT; i++) {
+ (iov + i)->iov_base = (data + pagesz * i);
+ (iov + i)->iov_len = 1;
+ }
+
+ if ((fd = open(argv[1], O_TRUNC|O_CREAT|O_RDWR, 0644)) < 0) {
+ perror("open failed");
+ return 1;
+ }
+
+
+ ret = writev(fd, iov, IOV_CNT);
+ if (ret < 0)
+ perror("writev failed");
+ else
+ printf("wrote %d bytes\n", (int)ret);
+
+ close(fd);
+ return 0;
+}
diff --git a/tests/generic/441 b/tests/generic/441
new file mode 100755
index 0000000..89e12b0
--- /dev/null
+++ b/tests/generic/441
@@ -0,0 +1,61 @@
+#! /bin/bash
+# FS QA Test 441
+#
+# Takes page fault while writev is iterating over the vectors in the IOV
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2017 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
+
+# remove previous $seqres.full before test
+rm -f $seqres.full
+
+# real QA test starts here
+_supported_fs generic
+_supported_os Linux
+_require_test
+_require_test_program "writev_on_pagefault"
+
+# This program use several vectors for writev(), the kernel goes over them
+# one at a time, copying them from userspace, getting the user data ready
+# for IO. If it takes a page fault while iterating over the vectors in the
+# IOV, it stops, and sends what it got so far. We try to find a bug at this
+# moment.
+$here/src/writev_on_pagefault $TEST_DIR/testfile.$seq
+
+# success, all done
+status=0
+exit
diff --git a/tests/generic/441.out b/tests/generic/441.out
new file mode 100644
index 0000000..2d5acf9
--- /dev/null
+++ b/tests/generic/441.out
@@ -0,0 +1,2 @@
+QA output created by 441
+wrote 3 bytes
diff --git a/tests/generic/group b/tests/generic/group
index ab1e9d3..5046c97 100644
--- a/tests/generic/group
+++ b/tests/generic/group
@@ -443,3 +443,4 @@
438 auto
439 auto quick punch
440 auto quick encrypt
+441 auto quick rw
--
2.7.5
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