From patchwork Thu Aug 12 21:40:09 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: 12434323 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B78A6C4338F for ; Thu, 12 Aug 2021 21:41:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9A60C60F00 for ; Thu, 12 Aug 2021 21:41:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238073AbhHLVmP (ORCPT ); Thu, 12 Aug 2021 17:42:15 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:45978 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238058AbhHLVmO (ORCPT ); Thu, 12 Aug 2021 17:42:14 -0400 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: krisman) with ESMTPSA id 869DF1F41890 From: Gabriel Krisman Bertazi To: amir73il@gmail.com, jack@suse.com Cc: linux-api@vger.kernel.org, linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, khazhy@google.com, dhowells@redhat.com, david@fromorbit.com, tytso@mit.edu, djwong@kernel.org, repnop@google.com, Gabriel Krisman Bertazi , kernel@collabora.com Subject: [PATCH v6 20/21] samples: Add fs error monitoring example Date: Thu, 12 Aug 2021 17:40:09 -0400 Message-Id: <20210812214010.3197279-21-krisman@collabora.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210812214010.3197279-1-krisman@collabora.com> References: <20210812214010.3197279-1-krisman@collabora.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Introduce an example of a FAN_FS_ERROR fanotify user to track filesystem errors. Reviewed-by: Amir Goldstein Signed-off-by: Gabriel Krisman Bertazi --- Changes since v4: - Protect file_handle defines with ifdef guards Changes since v1: - minor fixes --- samples/Kconfig | 9 +++ samples/Makefile | 1 + samples/fanotify/Makefile | 5 ++ samples/fanotify/fs-monitor.c | 138 ++++++++++++++++++++++++++++++++++ 4 files changed, 153 insertions(+) create mode 100644 samples/fanotify/Makefile create mode 100644 samples/fanotify/fs-monitor.c diff --git a/samples/Kconfig b/samples/Kconfig index b0503ef058d3..88353b8eac0b 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..e20db1bdde3b --- /dev/null +++ b/samples/fanotify/Makefile @@ -0,0 +1,5 @@ +# SPDX-License-Identifier: GPL-2.0-only +userprogs-always-y += fs-monitor + +userccflags += -I usr/include -Wall + diff --git a/samples/fanotify/fs-monitor.c b/samples/fanotify/fs-monitor.c new file mode 100644 index 000000000000..e115053382be --- /dev/null +++ b/samples/fanotify/fs-monitor.c @@ -0,0 +1,138 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright 2021, Collabora Ltd. + */ + +#define _GNU_SOURCE +#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; +}; +#endif + +#ifndef FILEID_INO32_GEN +#define FILEID_INO32_GEN 1 +#endif + +#ifndef FILEID_INVALID +#define FILEID_INVALID 0xff +#endif + +static void print_fh(struct file_handle *fh) +{ + int i; + uint32_t *h = (uint32_t *) fh->f_handle; + + printf("\tfh: "); + for (i = 0; i < fh->handle_bytes; i++) + printf("%hhx", fh->f_handle[i]); + printf("\n"); + + printf("\tdecoded fh: "); + if (fh->handle_type == FILEID_INO32_GEN) + printf("inode=%u gen=%u\n", h[0], h[1]); + else if (fh->handle_type == FILEID_INVALID && !fh->handle_bytes) + printf("Type %d (Superblock error)\n", fh->handle_type); + else + printf("Type %d (Unknown)\n", fh->handle_type); + +} + +static void handle_notifications(char *buffer, int len) +{ + struct fanotify_event_metadata *metadata; + struct fanotify_event_info_error *error; + struct fanotify_event_info_fid *fid; + char *next; + + for (metadata = (struct fanotify_event_metadata *) buffer; + FAN_EVENT_OK(metadata, len); + metadata = FAN_EVENT_NEXT(metadata, len)) { + next = (char *)metadata + metadata->event_len; + if (metadata->mask != FAN_FS_ERROR) { + printf("unexpected FAN MARK: %llx\n", metadata->mask); + goto next_event; + } else if (metadata->fd != FAN_NOFD) { + printf("Unexpected fd (!= FAN_NOFD)\n"); + goto next_event; + } + + 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 (Expecting TYPE_ERROR)\n", + error->hdr.info_type); + goto next_event; + } + + printf("\tGeneric Error Record: len=%d\n", error->hdr.len); + printf("\terror: %d\n", error->error); + printf("\terror_count: %d\n", error->error_count); + + fid = (struct fanotify_event_info_fid *) (error + 1); + if ((char *) fid >= next) { + printf("Event doesn't have FID\n"); + goto next_event; + } + printf("FID record found\n"); + + if (fid->hdr.info_type != FAN_EVENT_INFO_TYPE_FID) { + printf("unknown record: %d (Expecting TYPE_FID)\n", + fid->hdr.info_type); + goto next_event; + } + printf("\tfsid: %x%x\n", fid->fsid.val[0], fid->fsid.val[1]); + print_fh((struct file_handle *) &fid->handle); + +next_event: + printf("---\n\n"); + } +} + +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|FAN_REPORT_FID, 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; +}