Added write cache tests.

test/.gitignore

@@ -1,2 +1,3 @@
 test
+test_write_cache
 __pycache__/

test/Makefile.am

@@ -1,2 +1,6 @@
-bin_PROGRAMS = test
-test_SOURCES = test.c
+## Process this file with automake to produce Makefile.in
+
+AM_CPPFLAGS = -I$(top_srcdir)/include -D_REENTRANT
+noinst_PROGRAMS = test test_write_cache
+
+test_write_cache_LDADD = ../lib/libfuse3.la

test/test_examples.py

@@ -211,6 +211,18 @@ def test_notify_inval_entry(tmpdir, notify):
     else:
         umount(mount_process, mnt_dir)
 
+@pytest.mark.parametrize("writeback", (True, False))
+def test_write_cache(tmpdir, writeback):
+    # This test hangs under Valgrind when running close(fd)
+    # test_write_cache.c:test_fs(). Most likely this is because of an internal
+    # deadlock in valgrind, it probably assumes that until close() returns,
+    # control does not come to the program.
+    mnt_dir = str(tmpdir)
+    cmdline = [ pjoin(basename, 'test', 'test_write_cache'),
+                mnt_dir ]
+    if writeback:
+        cmdline.append('-owriteback_cache')
+    subprocess.check_call(cmdline)
 
 @pytest.mark.skipif(os.getuid() != 0,
                     reason='needs to run as root')

test/test_write_cache.c

@@ -0,0 +1,206 @@
+/*
+  FUSE: Filesystem in Userspace
+  Copyright (C) 2016 Nikolaus Rath <Nikolaus@rath.org>
+
+  This program can be distributed under the terms of the GNU GPL.
+  See the file COPYING.
+*/
+
+
+#define FUSE_USE_VERSION 30
+
+#include <config.h>
+#include <fuse_lowlevel.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <assert.h>
+#include <stddef.h>
+#include <unistd.h>
+#include <pthread.h>
+#include <linux/limits.h>
+
+#define FILE_INO 2
+#define FILE_NAME "write_me"
+
+/* Command line parsing */
+struct options {
+    int writeback;
+    int data_size;
+} options = {
+    .writeback = 0,
+    .data_size = 4096,
+};
+
+#define OPTION(t, p)                           \
+    { t, offsetof(struct options, p), 1 }
+static const struct fuse_opt option_spec[] = {
+    OPTION("writeback_cache", writeback),
+    OPTION("--data-size=%d", data_size),
+    FUSE_OPT_KEY("writeback_cache", FUSE_OPT_KEY_KEEP),
+    FUSE_OPT_END
+};
+static int got_write;
+
+static int tfs_stat(fuse_ino_t ino, struct stat *stbuf) {
+    stbuf->st_ino = ino;
+    if (ino == FUSE_ROOT_ID) {
+        stbuf->st_mode = S_IFDIR | 0755;
+        stbuf->st_nlink = 1;
+    }
+
+    else if (ino == FILE_INO) {
+        stbuf->st_mode = S_IFREG | 0222;
+        stbuf->st_nlink = 1;
+        stbuf->st_size = 0;
+    }
+
+    else
+        return -1;
+
+    return 0;
+}
+
+static void tfs_lookup(fuse_req_t req, fuse_ino_t parent,
+                       const char *name) {
+    struct fuse_entry_param e;
+    memset(&e, 0, sizeof(e));
+
+    if (parent != FUSE_ROOT_ID)
+        goto err_out;
+    else if (strcmp(name, FILE_NAME) == 0)
+        e.ino = FILE_INO;
+    else
+        goto err_out;
+
+    if (tfs_stat(e.ino, &e.attr) != 0)
+        goto err_out;
+    fuse_reply_entry(req, &e);
+    return;
+
+err_out:
+    fuse_reply_err(req, ENOENT);
+}
+
+static void tfs_getattr(fuse_req_t req, fuse_ino_t ino,
+                        struct fuse_file_info *fi) {
+    struct stat stbuf;
+
+    (void) fi;
+
+    memset(&stbuf, 0, sizeof(stbuf));
+    if (tfs_stat(ino, &stbuf) != 0)
+        fuse_reply_err(req, ENOENT);
+    else
+        fuse_reply_attr(req, &stbuf, 5);
+}
+
+static void tfs_open(fuse_req_t req, fuse_ino_t ino,
+                     struct fuse_file_info *fi) {
+    if (ino == FUSE_ROOT_ID)
+        fuse_reply_err(req, EISDIR);
+    else {
+        assert(ino == FILE_INO);
+        fuse_reply_open(req, fi);
+    }
+}
+
+static void tfs_write(fuse_req_t req, fuse_ino_t ino, const char *buf,
+                      size_t size, off_t off, struct fuse_file_info *fi) {
+    (void) fi; (void) buf; (void) off;
+    size_t expected;
+
+    assert(ino == FILE_INO);
+    expected = options.data_size;
+    if(options.writeback)
+        expected *= 2;
+
+    if(size != expected)
+        fprintf(stderr, "ERROR: Expected %zd bytes, got %zd\n!",
+                expected, size);
+    else
+        got_write = 1;
+    fuse_reply_write(req, size);
+}
+
+static struct fuse_lowlevel_ops tfs_oper = {
+    .lookup	= tfs_lookup,
+    .getattr	= tfs_getattr,
+    .open	= tfs_open,
+    .write	= tfs_write,
+};
+
+static void* run_fs(void *data) {
+    struct fuse_session *se = (struct fuse_session*) data;
+    assert(fuse_session_loop(se) == 0);
+    return NULL;
+}
+
+static void test_fs(char *mountpoint) {
+    char fname[PATH_MAX];
+    char *buf;
+    size_t dsize = options.data_size;
+    int fd;
+
+    buf = malloc(dsize);
+    assert(buf != NULL);
+    assert((fd = open("/dev/urandom", O_RDONLY)) != -1);
+    assert(read(fd, buf, dsize) == dsize);
+    close(fd);
+
+    assert(snprintf(fname, PATH_MAX, "%s/write_me",
+                     mountpoint) > 0);
+    fd = open(fname, O_WRONLY);
+    if (fd == -1) {
+        perror(fname);
+        assert(0);
+    }
+
+    assert(write(fd, buf, dsize) == dsize);
+    assert(write(fd, buf, dsize) == dsize);
+    close(fd);
+}
+
+int main(int argc, char *argv[]) {
+    struct fuse_args args = FUSE_ARGS_INIT(argc, argv);
+    struct fuse_session *se;
+    struct fuse_cmdline_opts fuse_opts;
+    pthread_t fs_thread;
+
+    assert(fuse_opt_parse(&args, &options, option_spec, NULL) == 0);
+    assert(fuse_parse_cmdline(&args, &fuse_opts) == 0);
+    assert(fuse_opt_add_arg(&args, "-oauto_unmount") == 0);
+    se = fuse_session_new(&args, &tfs_oper,
+                          sizeof(tfs_oper), NULL);
+    assert (se != NULL);
+    assert(fuse_set_signal_handlers(se) == 0);
+    assert(fuse_session_mount(se, fuse_opts.mountpoint) == 0);
+
+    /* Start file-system thread */
+    assert(pthread_create(&fs_thread, NULL, run_fs, (void *)se) == 0);
+
+    /* Write test data */
+    test_fs(fuse_opts.mountpoint);
+
+    /* Stop file system */
+    assert(pthread_cancel(fs_thread) == 0);
+
+    fuse_session_unmount(se);
+    assert(got_write == 1);
+    fuse_remove_signal_handlers(se);
+    fuse_session_destroy(se);
+
+    printf("Test completed successfully.\n");
+    return 0;
+}
+
+
+/**
+ * Local Variables:
+ * mode: c
+ * indent-tabs-mode: nil
+ * c-basic-offset: 4
+ * End:
+ */