+#define DLSYM(prefix, sym, func) \
+ do { \
+ char _fname[64]; \
+ snprintf(_fname, sizeof(_fname), "%s_%s", prefix, #func); \
+ sym->func = (typeof(sym->func))dlsym(sym->dl_handle, _fname); \
+ } while (0)
+
+/**
+ * Load plugin for a given mount_type from ${pkglibdir}/mount_osd_FSTYPE.so and
+ * return struct of function pointers (will be freed in unloack_backfs_module).
+ *
+ * \param[in] mount_type Mount type to load module for.
+ * \retval Value of backfs_ops struct
+ * \retval NULL if no module exists
+ */
+struct module_backfs_ops *load_backfs_module(enum ldd_mount_type mount_type)
+{
+ void *handle;
+ char *error, filename[512], fsname[512], *name;
+ struct module_backfs_ops *ops;
+
+ /* This deals with duplicate ldd_mount_types resolving to same OSD layer
+ * plugin (e.g. ext3/ldiskfs/ldiskfs2 all being ldiskfs) */
+ strncpy(fsname, mt_type(mount_type), sizeof(fsname));
+ name = fsname + sizeof("osd-") - 1;
+
+ /* change osd- to osd_ */
+ fsname[sizeof("osd-") - 2] = '_';
+
+ snprintf(filename, sizeof(filename), PLUGIN_DIR"/mount_%s.so", fsname);
+
+ handle = dlopen(filename, RTLD_LAZY);
+ if (handle == NULL)
+ /* Do not clutter up console with missing types */
+ return NULL;
+
+ ops = malloc(sizeof(*ops));
+ if (ops == NULL) {
+ dlclose(handle);
+ return NULL;
+ }
+
+ ops->dl_handle = handle;
+ dlerror(); /* Clear any existing error */
+
+ DLSYM(name, ops, init);
+ DLSYM(name, ops, fini);
+ DLSYM(name, ops, read_ldd);
+ DLSYM(name, ops, write_ldd);
+ DLSYM(name, ops, is_lustre);
+ DLSYM(name, ops, make_lustre);
+ DLSYM(name, ops, prepare_lustre);
+ DLSYM(name, ops, tune_lustre);
+ DLSYM(name, ops, label_lustre);
+ DLSYM(name, ops, enable_quota);
+
+ error = dlerror();
+ if (error != NULL) {
+ fatal();
+ fprintf(stderr, "%s\n", error);
+ dlclose(handle);
+ free(ops);
+ return NULL;
+ }
+ return ops;
+}
+
+/**
+ * Unload plugin and free backfs_ops structure. Must be called the same number
+ * of times as load_backfs_module is.
+ */
+void unload_backfs_module(struct module_backfs_ops *ops)
+{
+ if (ops == NULL)
+ return;
+
+ dlclose(ops->dl_handle);
+ free(ops);
+}
+
+/* Return true if backfs_ops has operations for the given mount_type. */
+int backfs_mount_type_okay(enum ldd_mount_type mount_type)
+{
+ if (unlikely(mount_type >= LDD_MT_LAST || mount_type < 0)) {
+ fatal();
+ fprintf(stderr, "fs type out of range %d\n", mount_type);
+ return 0;
+ }
+ if (backfs_ops[mount_type] == NULL) {
+ fatal();
+ fprintf(stderr, "unhandled fs type %d '%s'\n",
+ mount_type, mt_str(mount_type));
+ return 0;
+ }
+ return 1;
+}
+
git://git.whamcloud.com / fs / lustre-release.git / commitdiff