Hi, This is the 5th version of the FAN_FS_ERROR patches. This applies the feedback from last version (thanks Amir, Jan). Biggest changes are the split up of the FAN_FS_ERROR patch into something more reviewable, and the removal of the event_info structure due to the perf regression shown by unixbench. This was tested with LTP for regressions, and also using the sample on the last patch, with a corrupted image. I wrote a new ltp test for this feature which is being reviewed and is available at: https://gitlab.collabora.com/krisman/ltp -b fan-fs-error In addition, I wrote a man-page that can be pulled from: https://gitlab.collabora.com/krisman/man-pages.git -b fan-fs-error And is being reviewed at the list. I also pushed this 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 Cc: linux-api@xxxxxxxxxxxxxxx Cc: linux-api@xxxxxxxxxxxxxxx Gabriel Krisman Bertazi (23): fsnotify: Don't insert unmergeable events in hashtable fanotify: Fold event size calculation to its own function fanotify: Split fsid check from other fid mode checks fsnotify: Reserve mark bits for backends fanotify: Split superblock marks out to a new cache inotify: Don't force FS_IN_IGNORED fsnotify: Add helper to detect overflow_event fsnotify: Add wrapper around fsnotify_add_event fsnotify: Support passing argument to insert callback on add_event fsnotify: Allow events reported with an empty inode fsnotify: Support FS_ERROR event type fanotify: Expose helper to estimate file handle encoding length fanotify: Allow file handle encoding for unhashed events fanotify: Encode invalid file handler when no inode is provided fanotify: Require fid_mode for any non-fd event fanotify: Reserve UAPI bits for FAN_FS_ERROR fanotify: Preallocate per superblock mark error event fanotify: Handle FAN_FS_ERROR events fanotify: Report fid info for file related file system errors fanotify: Emit generic error info type for error event ext4: Send notifications on error samples: Add fs error monitoring example docs: Document the FAN_FS_ERROR event .../admin-guide/filesystem-monitoring.rst | 70 +++++ Documentation/admin-guide/index.rst | 1 + fs/ext4/super.c | 8 + fs/kernfs/file.c | 6 +- fs/notify/fanotify/fanotify.c | 186 +++++++++--- fs/notify/fanotify/fanotify.h | 80 +++++- fs/notify/fanotify/fanotify_user.c | 266 +++++++++++++++--- fs/notify/fsnotify.c | 14 +- fs/notify/inotify/inotify_fsnotify.c | 2 +- fs/notify/inotify/inotify_user.c | 6 +- fs/notify/notification.c | 16 +- include/linux/fanotify.h | 9 +- include/linux/fsnotify.h | 20 +- include/linux/fsnotify_backend.h | 76 ++++- include/uapi/linux/fanotify.h | 8 + samples/Kconfig | 9 + samples/Makefile | 1 + samples/fanotify/Makefile | 5 + samples/fanotify/fs-monitor.c | 138 +++++++++ 19 files changed, 803 insertions(+), 118 deletions(-) create mode 100644 Documentation/admin-guide/filesystem-monitoring.rst create mode 100644 samples/fanotify/Makefile create mode 100644 samples/fanotify/fs-monitor.c -- 2.32.0
