From patchwork Tue Jun 15 23:55:42 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: 1492537 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 4G4QFK1pCRz9sWQ for ; Wed, 16 Jun 2021 09:56:05 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230039AbhFOX6J (ORCPT ); Tue, 15 Jun 2021 19:58:09 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:39890 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229811AbhFOX6I (ORCPT ); Tue, 15 Jun 2021 19:58:08 -0400 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: krisman) with ESMTPSA id 214931F432D2 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 00/14] File system wide monitoring Date: Tue, 15 Jun 2021 19:55:42 -0400 Message-Id: <20210615235556.970928-1-krisman@collabora.com> X-Mailer: git-send-email 2.31.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org Hi, This follows up on the previous version [2]. There is not much design changes, except to attend to Amir and Darrick's reviews. Thank you both so much for the detailed feedback. It is really appreciated. I decided not to implement FID mode reporting in this version, since it can be extended later without prejudice to the user API. This version also includes a small fix to fsnotify_add_event on patch 1 to prevent adding overflow events to the hash map. This was tested with LTP for regressions, and also using the sample on the last patch, with a corrupted image. I can publish the bad image upon request. I also pushed the full series to: https://gitlab.collabora.com/krisman/linux -b fanotify-notifications-single-slot Thank you Original cover letter --------------------- Hi, This series follow up on my previous proposal [1] to support file system wide monitoring. As suggested by Amir, this proposal drops the ring buffer in favor of a single slot associated with each mark. This simplifies a bit the implementation, as you can see in the code. As a reminder, This proposal is limited to an interface for administrators to monitor the health of a file system, instead of a generic inteface for file errors. Therefore, this doesn't solve the problem of writeback errors or the need to watch a specific subtree. In comparison to the previous RFC, this implementation also drops the per-fs data and location, and leave those as future extensions. * Implementation The feature is implemented on top of fanotify, as a new type of fanotify mark, FAN_ERROR, which a file system monitoring tool can register to receive error notifications. When an error occurs a new notification is generated, in addition followed by this info field: - FS generic data: A file system agnostic structure that has a generic error code and identifies the filesystem. Basically, it let's userspace know something happened on a monitored filesystem. Since only the first error is recorded since the last read, this also includes a counter of errors that happened since the last read. * Testing This was tested by watching notifications flowing from an intentionally corrupted filesystem in different places. In addition, other events were watched in an attempt to detect regressions. Is there a specific testsuite for fanotify I should be running? * Patches This patchset is divided as follows: Patch 1 through 5 are refactoring to fsnotify/fanotify in preparation for FS_ERROR/FAN_ERROR; patch 6 and 7 implement the FS_ERROR API for filesystems to report error; patch 8 add support for FAN_ERROR in fanotify; Patch 9 is an example implementation for ext4; patch 10 and 11 provide a sample userspace code and documentation. I also pushed the full series to: https://gitlab.collabora.com/krisman/linux -b fanotify-notifications-single-slot [1] https://lwn.net/Articles/854545/ [2] https://lwn.net/Articles/856916/ Cc: Darrick J. Wong Cc: Theodore Ts'o Cc: Dave Chinner Cc: jack@suse.com To: amir73il@gmail.com Cc: dhowells@redhat.com Cc: khazhy@google.com Cc: linux-fsdevel@vger.kernel.org Cc: linux-ext4@vger.kernel.org Amir Goldstein (1): fsnotify: pass arguments of fsnotify() in struct fsnotify_event_info Gabriel Krisman Bertazi (13): fsnotify: Don't call insert hook for overflow events fanotify: Fold event size calculation to its own function fanotify: Split fsid check from other fid mode checks fanotify: Split superblock marks out to a new cache inotify: Don't force FS_IN_IGNORED fsnotify: Add helper to detect overflow_event fsnotify: Support passing argument to insert callback on add_event fsnotify: Support FS_ERROR event type fsnotify: Introduce helpers to send error_events fanotify: Introduce FAN_FS_ERROR event ext4: Send notifications on error samples: Add fs error monitoring example Documentation: Document the FAN_FS_ERROR event .../admin-guide/filesystem-monitoring.rst | 63 +++++ Documentation/admin-guide/index.rst | 1 + fs/ext4/super.c | 8 + fs/notify/fanotify/fanotify.c | 187 ++++++++++++--- fs/notify/fanotify/fanotify.h | 44 +++- fs/notify/fanotify/fanotify_user.c | 226 +++++++++++++++--- fs/notify/fsnotify.c | 85 ++++--- fs/notify/inotify/inotify_fsnotify.c | 2 +- fs/notify/inotify/inotify_user.c | 6 +- fs/notify/notification.c | 12 +- include/linux/fanotify.h | 6 +- include/linux/fsnotify.h | 35 ++- include/linux/fsnotify_backend.h | 104 ++++++-- include/uapi/linux/fanotify.h | 11 + samples/Kconfig | 9 + samples/Makefile | 1 + samples/fanotify/Makefile | 3 + samples/fanotify/fs-monitor.c | 95 ++++++++ 18 files changed, 752 insertions(+), 146 deletions(-) create mode 100644 Documentation/admin-guide/filesystem-monitoring.rst create mode 100644 samples/fanotify/Makefile create mode 100644 samples/fanotify/fs-monitor.c