Fix race condition in notify_* examples

The fix in commit cf4159156b was incomplete. While some false positives
are caused by sleep() in the file system taking longer than expected,
there was also a race condition where the file system would run before
the contents are initialized properly.

diff --git a/example/notify_inval_entry.c b/example/notify_inval_entry.c
index d5da1c570bbf9d6e88edee5ff338dca2ca82799a..898eff18330f2b66361b426529ff2c02180b2917 100644 (file)
--- a/example/notify_inval_entry.c
+++ b/example/notify_inval_entry.c
@@ -232,23 +232,27 @@ static struct fuse_lowlevel_ops tfs_oper = {
     .forget     = tfs_forget,
 };
 
-static void* update_fs(void *data) {
-    struct fuse_session *se = (struct fuse_session*) data;
-    struct tm *now;
-    char *old_name;
+static void update_fs(void) {
     time_t t;
+    struct tm *now;
     ssize_t ret;
 
-    while(1) {
-        t = time(NULL);
-        now = localtime(&t);
-        assert(now != NULL);
+    t = time(NULL);
+    now = localtime(&t);
+    assert(now != NULL);
 
-        old_name = strdup(file_name);
-        ret = strftime(file_name, MAX_STR_LEN,
-                       "Time_is_%Hh_%Mm_%Ss", now);
-        assert(ret != 0);
+    ret = strftime(file_name, MAX_STR_LEN,
+                   "Time_is_%Hh_%Mm_%Ss", now);
+    assert(ret != 0);
+}
 
+static void* update_fs_loop(void *data) {
+    struct fuse_session *se = (struct fuse_session*) data;
+    char *old_name;
+
+    while(1) {
+        old_name = strdup(file_name);
+        update_fs();
         if (!options.no_notify && lookup_cnt)
             assert(fuse_lowlevel_notify_inval_entry
                    (se, FUSE_ROOT_ID, old_name, strlen(old_name)) == 0);
@@ -295,6 +299,9 @@ int main(int argc, char *argv[]) {
         goto err_out1;
     }
 
+    /* Initial contents */
+    update_fs();
+
     se = fuse_session_new(&args, &tfs_oper,
                           sizeof(tfs_oper), NULL);
     if (se == NULL)
@@ -309,7 +316,7 @@ int main(int argc, char *argv[]) {
     fuse_daemonize(opts.foreground);
 
     /* Start thread to update file contents */
-    ret = pthread_create(&updater, NULL, update_fs, (void *)se);
+    ret = pthread_create(&updater, NULL, update_fs_loop, (void *)se);
     if (ret != 0) {
         fprintf(stderr, "pthread_create failed with %s\n",
                 strerror(ret));

diff --git a/example/notify_inval_inode.c b/example/notify_inval_inode.c
index 9cd7e95374aa11c4ac280a34083cbaa6378ea435..1b813a0324810d25412c0a73f1376cd252d3d437 100644 (file)
--- a/example/notify_inval_inode.c
+++ b/example/notify_inval_inode.c
@@ -255,19 +255,23 @@ static struct fuse_lowlevel_ops tfs_oper = {
     .forget     = tfs_forget,
 };
 
-static void* update_fs(void *data) {
-    struct fuse_session *se = (struct fuse_session*) data;
+static void update_fs(void) {
     struct tm *now;
     time_t t;
+    t = time(NULL);
+    now = localtime(&t);
+    assert(now != NULL);
 
-    while(1) {
-        t = time(NULL);
-        now = localtime(&t);
-        assert(now != NULL);
+    file_size = strftime(file_contents, MAX_STR_LEN,
+                         "The current time is %H:%M:%S\n", now);
+    assert(file_size != 0);
+}
 
-        file_size = strftime(file_contents, MAX_STR_LEN,
-                             "The current time is %H:%M:%S\n", now);
-        assert(file_size != 0);
+static void* update_fs_loop(void *data) {
+    struct fuse_session *se = (struct fuse_session*) data;
+
+    while(1) {
+        update_fs();
         if (!options.no_notify && lookup_cnt) {
             /* Only send notification if the kernel
                is aware of the inode */
@@ -318,6 +322,9 @@ int main(int argc, char *argv[]) {
         goto err_out1;
     }
 
+    /* Initial contents */
+    update_fs();
+
     se = fuse_session_new(&args, &tfs_oper,
                           sizeof(tfs_oper), NULL);
     if (se == NULL)
@@ -332,7 +339,7 @@ int main(int argc, char *argv[]) {
     fuse_daemonize(opts.foreground);
 
     /* Start thread to update file contents */
-    ret = pthread_create(&updater, NULL, update_fs, (void *)se);
+    ret = pthread_create(&updater, NULL, update_fs_loop, (void *)se);
     if (ret != 0) {
         fprintf(stderr, "pthread_create failed with %s\n",
                 strerror(ret));

diff --git a/example/notify_store_retrieve.c b/example/notify_store_retrieve.c
index cc7e8657ddb58263bb766a7b504ef6dfe5bc9701..76f3291503ab61f2ab43b203e6397d44043736ac 100644 (file)
--- a/example/notify_store_retrieve.c
+++ b/example/notify_store_retrieve.c
@@ -286,20 +286,24 @@ static struct fuse_lowlevel_ops tfs_oper = {
     .retrieve_reply = tfs_retrieve_reply,
 };
 
-static void* update_fs(void *data) {
-    struct fuse_session *se = (struct fuse_session*) data;
+static void update_fs(void) {
     struct tm *now;
     time_t t;
+    t = time(NULL);
+    now = localtime(&t);
+    assert(now != NULL);
+
+    file_size = strftime(file_contents, MAX_STR_LEN,
+                         "The current time is %H:%M:%S\n", now);
+    assert(file_size != 0);
+}
+
+static void* update_fs_loop(void *data) {
+    struct fuse_session *se = (struct fuse_session*) data;
     struct fuse_bufvec bufv;
 
     while(1) {
-        t = time(NULL);
-        now = localtime(&t);
-        assert(now != NULL);
-
-        file_size = strftime(file_contents, MAX_STR_LEN,
-                             "The current time is %H:%M:%S\n", now);
-        assert(file_size != 0);
+        update_fs();
         if (!options.no_notify && lookup_cnt) {
             /* Only send notification if the kernel
                is aware of the inode */
@@ -361,6 +365,9 @@ int main(int argc, char *argv[]) {
         goto err_out1;
     }
 
+    /* Initial contents */
+    update_fs();
+
     se = fuse_session_new(&args, &tfs_oper,
                           sizeof(tfs_oper), NULL);
     if (se == NULL)
@@ -375,7 +382,7 @@ int main(int argc, char *argv[]) {
     fuse_daemonize(opts.foreground);
 
     /* Start thread to update file contents */
-    ret = pthread_create(&updater, NULL, update_fs, (void *)se);
+    ret = pthread_create(&updater, NULL, update_fs_loop, (void *)se);
     if (ret != 0) {
         fprintf(stderr, "pthread_create failed with %s\n",
                 strerror(ret));

diff --git a/test/test_examples.py b/test/test_examples.py
index 2990d254e767dbdb82c77140fc35b22151109072..e0f9be482fdca97e51b7ea0d39fb9fd1047c233d 100755 (executable)
--- a/test/test_examples.py
+++ b/test/test_examples.py
@@ -151,21 +151,16 @@ def test_notify1(tmpdir, name, options, notify):
     mnt_dir = str(tmpdir)
     cmdline = base_cmdline + \
               [ pjoin(basename, 'example', name),
-                '-f', '--update-interval=2', mnt_dir ] + options
+                '-f', '--update-interval=1', mnt_dir ] + options
     if not notify:
         cmdline.append('--no-notify')
     mount_process = subprocess.Popen(cmdline)
     try:
         wait_for_mount(mount_process, mnt_dir)
         filename = pjoin(mnt_dir, 'current_time')
-        # Wait until first update
-        while True:
-            with open(filename, 'r') as fh:
-                read1 = fh.read()
-            if read1:
-                break
-            safe_sleep(2)
-        safe_sleep(6)
+        with open(filename, 'r') as fh:
+            read1 = fh.read()
+        safe_sleep(2)
         with open(filename, 'r') as fh:
             read2 = fh.read()
         if notify:
@@ -183,8 +178,8 @@ def test_notify_inval_entry(tmpdir, notify):
     mnt_dir = str(tmpdir)
     cmdline = base_cmdline + \
               [ pjoin(basename, 'example', 'notify_inval_entry'),
-               '-f', '--update-interval=2',
-                '--timeout=10', mnt_dir ]
+                '-f', '--update-interval=1',
+                '--timeout=5', mnt_dir ]
     if not notify:
         cmdline.append('--no-notify')
     mount_process = subprocess.Popen(cmdline)
@@ -199,10 +194,10 @@ def test_notify_inval_entry(tmpdir, notify):
             fname = pjoin(mnt_dir, os.listdir(mnt_dir)[0])
             os.stat(fname)
 
-        safe_sleep(4)
+        safe_sleep(2)
         if not notify:
             os.stat(fname)
-            safe_sleep(10)
+            safe_sleep(5)
         with pytest.raises(FileNotFoundError):
             os.stat(fname)
     except: