Merge tag 'fsnotify_for_v5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs

Pull fsnotify updates from Jan Kara:
 "Support for reporting filesystem errors through fanotify so that
  system health monitoring daemons can watch for these and act instead
  of scraping system logs"

* tag 'fsnotify_for_v5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: (34 commits)
  samples: remove duplicate include in fs-monitor.c
  samples: Fix warning in fsnotify sample
  docs: Fix formatting of literal sections in fanotify docs
  samples: Make fs-monitor depend on libc and headers
  docs: Document the FAN_FS_ERROR event
  samples: Add fs error monitoring example
  ext4: Send notifications on error
  fanotify: Allow users to request FAN_FS_ERROR events
  fanotify: Emit generic error info for error event
  fanotify: Report fid info for file related file system errors
  fanotify: WARN_ON against too large file handles
  fanotify: Add helpers to decide whether to report FID/DFID
  fanotify: Wrap object_fh inline space in a creator macro
  fanotify: Support merging of error events
  fanotify: Support enqueueing of error events
  fanotify: Pre-allocate pool of error events
  fanotify: Reserve UAPI bits for FAN_FS_ERROR
  fsnotify: Support FS_ERROR event type
  fanotify: Require fid_mode for any non-fd event
  fanotify: Encode empty file handle when no inode is provided
  ...

1 files changed, 8 insertions, 0 deletions

diff --git a/include/uapi/linux/fanotify.h b/include/uapi/linux/fanotify.h
index 64553df9d735..bd1932c2074d 100644
--- a/include/uapi/linux/fanotify.h
+++ b/include/uapi/linux/fanotify.h
@@ -20,6 +20,7 @@
 #define FAN_OPEN_EXEC		0x00001000	/* File was opened for exec */
 
 #define FAN_Q_OVERFLOW		0x00004000	/* Event queued overflowed */
+#define FAN_FS_ERROR		0x00008000	/* Filesystem error */
 
 #define FAN_OPEN_PERM		0x00010000	/* File open in perm check */
 #define FAN_ACCESS_PERM		0x00020000	/* File accessed in perm check */
@@ -125,6 +126,7 @@ struct fanotify_event_metadata {
 #define FAN_EVENT_INFO_TYPE_DFID_NAME	2
 #define FAN_EVENT_INFO_TYPE_DFID	3
 #define FAN_EVENT_INFO_TYPE_PIDFD	4
+#define FAN_EVENT_INFO_TYPE_ERROR	5
 
 /* Variable length info record following event metadata */
 struct fanotify_event_info_header {
@@ -159,6 +161,12 @@ struct fanotify_event_info_pidfd {
 	__s32 pidfd;
 };
 
+struct fanotify_event_info_error {
+	struct fanotify_event_info_header hdr;
+	__s32 error;
+	__u32 error_count;
+};
+
 struct fanotify_response {
 	__s32 fd;
 	__u32 response;