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 <djwong@xxxxxxxxxx> Cc: Theodore Ts'o <tytso@xxxxxxx> Cc: Dave Chinner <david@xxxxxxxxxxxxx> Cc: jack@xxxxxxxx To: amir73il@xxxxxxxxx Cc: dhowells@xxxxxxxxxx Cc: khazhy@xxxxxxxxxx Cc: linux-fsdevel@xxxxxxxxxxxxxxx Cc: linux-ext4@xxxxxxxxxxxxxxx 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 -- 2.31.0
