The following kernel commit introduced a race condition that causes
getcwd(2) to return "/" instead of correct path
232d2d6 dcache: Translating dentry into pathname without taking rename_lock
Jan Stancek hit it once when building ltp and Mikulas Patocka could
hit it by running lvm2 test suite. Please refer to this thread
https://www.mail-archive.com/ltp-list@lists.sourceforge.net/msg17896.html
These commits fixed the bug
ede4ceb prepend_path() needs to reinitialize dentry/vfsmount/mnt on restarts
f650080 __dentry_path() fixes
Cc: Artem Savkov <asavkov@redhat.com>
Cc: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
/src/t_dir_offset
/src/t_dir_offset2
/src/t_futimens
+/src/t_getcwd
/src/t_holes
/src/t_immutable
/src/t_mmap_writev
bulkstat_unlink_test_modified t_dir_offset t_futimens t_immutable \
stale_handle pwrite_mmap_blocked t_dir_offset2 seek_sanity_test \
seek_copy_test t_readdir_1 t_readdir_2 fsync-tester nsexec cloner \
- renameat2
+ renameat2 t_getcwd
SUBDIRS =
--- /dev/null
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define TIMEOUT 5
+#define BUF_SIZE 256
+
+static sig_atomic_t end;
+
+int test_getcwd(char *init_cwd)
+{
+ int i = 0;
+ char cur_cwd[BUF_SIZE];
+ while (1) {
+ getcwd(cur_cwd, BUF_SIZE);
+ if (strncmp(init_cwd, cur_cwd, BUF_SIZE)) {
+ printf("[%u] %s != %s\n", i, init_cwd, cur_cwd);
+ return 1;
+ }
+ if (end)
+ break;
+ i++;
+ }
+ return 0;
+}
+
+void do_rename(char *prefix)
+{
+ int i = 0;
+ int fd;
+ char c_name[BUF_SIZE];
+ char n_name[BUF_SIZE];
+
+ strncpy(c_name, prefix, BUF_SIZE);
+
+ fd = open(c_name, O_CREAT | O_RDWR, 0644);
+ if (fd < 0) {
+ fprintf(stderr, "failed to create file %s: %s\n",
+ c_name, strerror(errno));
+ exit(1);
+ }
+ close(fd);
+
+ while (1) {
+ i++;
+ snprintf(n_name, BUF_SIZE, "%s%u", prefix, i);
+ rename(c_name, n_name);
+ strncpy(c_name, n_name, BUF_SIZE);
+ }
+}
+
+void sigproc(int sig)
+{
+ end = 1;
+}
+
+int main(int argc, char *argv[])
+{
+ char *init_cwd;
+ pid_t pid;
+ int status;
+ int ret = 1;
+
+ if (argc != 2) {
+ printf("Usage: %s <dir>\n", argv[0]);
+ exit(1);
+ }
+
+ init_cwd = argv[1];
+ ret = chdir(init_cwd);
+ if (ret < 0) {
+ perror("chdir failed");
+ exit(1);
+ }
+
+ if (signal(SIGALRM, sigproc) == SIG_ERR) {
+ perror("signal failed");
+ exit(1);
+ }
+
+ alarm(TIMEOUT);
+
+ pid = fork();
+ if (pid < 0) {
+ perror("fork failed");
+ exit(1);
+ } else if (pid == 0) {
+ do_rename("t_getcwd_testfile");
+ } else {
+ ret = test_getcwd(init_cwd);
+ kill(pid, SIGTERM);
+ waitpid(pid, &status, 0);
+ }
+
+ exit(ret);
+}
--- /dev/null
+#! /bin/bash
+# FS QA Test No. generic/028
+#
+# The following commit introduced a race condition that causes getcwd(2)
+# to return "/" instead of correct path
+#
+# 232d2d6 dcache: Translating dentry into pathname without taking rename_lock
+#
+# These commits fixed the bug
+# ede4ceb prepend_path() needs to reinitialize dentry/vfsmount/mnt on restarts
+# f650080 __dentry_path() fixes
+#
+#-----------------------------------------------------------------------
+# 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 $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+
+# real QA test starts here
+_supported_fs generic
+_supported_os Linux
+
+echo "Silence is golden"
+
+$here/src/t_getcwd $TEST_DIR
+status=$?
+exit
--- /dev/null
+QA output created by 028
+Silence is golden
025 auto quick
026 acl quick auto
027 auto enospc
+028 auto quick
053 acl repair auto quick
062 attr udf auto quick
068 other auto freeze dangerous stress