From patchwork Tue Jun 15 23:55:55 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gabriel Krisman Bertazi X-Patchwork-Id: 1492550 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=linux-ext4-owner@vger.kernel.org; receiver=) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4G4QGK0ryWz9sWl for ; Wed, 16 Jun 2021 09:56:57 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231739AbhFOX7B (ORCPT ); Tue, 15 Jun 2021 19:59:01 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:40120 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231735AbhFOX66 (ORCPT ); Tue, 15 Jun 2021 19:58:58 -0400 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: krisman) with ESMTPSA id 182E61F4334C From: Gabriel Krisman Bertazi To: amir73il@gmail.com Cc: kernel@collabora.com, djwong@kernel.org, tytso@mit.edu, david@fromorbit.com, jack@suse.com, dhowells@redhat.com, khazhy@google.com, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, Gabriel Krisman Bertazi Subject: [PATCH v2 13/14] samples: Add fs error monitoring example Date: Tue, 15 Jun 2021 19:55:55 -0400 Message-Id: <20210615235556.970928-14-krisman@collabora.com> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20210615235556.970928-1-krisman@collabora.com> References: <20210615235556.970928-1-krisman@collabora.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org Introduce an example of a FAN_FS_ERROR fanotify user to track filesystem errors. Signed-off-by: Gabriel Krisman Bertazi Reported-by: kernel test robot --- Changes since v1: - minor fixes --- samples/Kconfig | 9 ++++ samples/Makefile | 1 + samples/fanotify/Makefile | 3 ++ samples/fanotify/fs-monitor.c | 95 +++++++++++++++++++++++++++++++++++ 4 files changed, 108 insertions(+) create mode 100644 samples/fanotify/Makefile create mode 100644 samples/fanotify/fs-monitor.c diff --git a/samples/Kconfig b/samples/Kconfig index b5a1a7aa7e23..f2f9c939035f 100644 --- a/samples/Kconfig +++ b/samples/Kconfig @@ -120,6 +120,15 @@ config SAMPLE_CONNECTOR with it. See also Documentation/driver-api/connector.rst +config SAMPLE_FANOTIFY_ERROR + bool "Build fanotify error monitoring sample" + depends on FANOTIFY + help + When enabled, this builds an example code that uses the + FAN_FS_ERROR fanotify mechanism to monitor filesystem + errors. + See also Documentation/admin-guide/filesystem-monitoring.rst. + config SAMPLE_HIDRAW bool "hidraw sample" depends on CC_CAN_LINK && HEADERS_INSTALL diff --git a/samples/Makefile b/samples/Makefile index 087e0988ccc5..931a81847c48 100644 --- a/samples/Makefile +++ b/samples/Makefile @@ -5,6 +5,7 @@ subdir-$(CONFIG_SAMPLE_AUXDISPLAY) += auxdisplay subdir-$(CONFIG_SAMPLE_ANDROID_BINDERFS) += binderfs obj-$(CONFIG_SAMPLE_CONFIGFS) += configfs/ obj-$(CONFIG_SAMPLE_CONNECTOR) += connector/ +obj-$(CONFIG_SAMPLE_FANOTIFY_ERROR) += fanotify/ subdir-$(CONFIG_SAMPLE_HIDRAW) += hidraw obj-$(CONFIG_SAMPLE_HW_BREAKPOINT) += hw_breakpoint/ obj-$(CONFIG_SAMPLE_KDB) += kdb/ diff --git a/samples/fanotify/Makefile b/samples/fanotify/Makefile new file mode 100644 index 000000000000..b3d5cc826e6f --- /dev/null +++ b/samples/fanotify/Makefile @@ -0,0 +1,3 @@ +userprogs-always-y += fs-monitor + +userccflags += -I usr/include diff --git a/samples/fanotify/fs-monitor.c b/samples/fanotify/fs-monitor.c new file mode 100644 index 000000000000..cb23a2592337 --- /dev/null +++ b/samples/fanotify/fs-monitor.c @@ -0,0 +1,95 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright 2021, Collabora Ltd. + */ + +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#ifndef FAN_FS_ERROR +#define FAN_FS_ERROR 0x00008000 +#define FAN_EVENT_INFO_TYPE_ERROR 4 + +struct fanotify_event_info_error { + struct fanotify_event_info_header hdr; + __s32 error; + __u32 error_count; + __kernel_fsid_t fsid; + __u64 ino; + __u32 ino_generation; +}; +#endif + +static void handle_notifications(char *buffer, int len) +{ + struct fanotify_event_metadata *metadata; + struct fanotify_event_info_error *error; + + for (metadata = (struct fanotify_event_metadata *) buffer; + FAN_EVENT_OK(metadata, len); + metadata = FAN_EVENT_NEXT(metadata, len)) { + if (metadata->mask != FAN_FS_ERROR) { + printf("unexpected FAN MARK: %llx\n", metadata->mask); + continue; + } else if (metadata->fd != FAN_NOFD) { + printf("Unexpected fd (!= FAN_NOFD)\n"); + continue; + } + + printf("FAN_FS_ERROR found len=%d\n", metadata->event_len); + + error = (struct fanotify_event_info_error *) (metadata+1); + if (error->hdr.info_type != FAN_EVENT_INFO_TYPE_ERROR) { + printf("unknown record: %d\n", error->hdr.info_type); + continue; + } + + printf("\tGeneric Error Record: len=%d\n", error->hdr.len); + printf("\tfsid: %x%x\n", error->fsid.val[0], + error->fsid.val[1]); + printf("\terror: %d\n", error->error); + printf("\tinode: %llu\tgen:%u\n", error->ino, + error->ino_generation); + printf("\terror_count: %d\n", error->error_count); + } +} + +int main(int argc, char **argv) +{ + int fd; + char buffer[BUFSIZ]; + + if (argc < 2) { + printf("Missing path argument\n"); + return 1; + } + + fd = fanotify_init(FAN_CLASS_NOTIF, O_RDONLY); + if (fd < 0) + errx(1, "fanotify_init"); + + if (fanotify_mark(fd, FAN_MARK_ADD|FAN_MARK_FILESYSTEM, + FAN_FS_ERROR, AT_FDCWD, argv[1])) { + errx(1, "fanotify_mark"); + } + + while (1) { + int n = read(fd, buffer, BUFSIZ); + + if (n < 0) + errx(1, "read"); + + handle_notifications(buffer, n); + } + + return 0; +}