xfs: start creating infrastructure for health monitoring

Source kernel commit: a48373e7d35a89f6f9b39f0d0da9bf158af054ee

Start creating helper functions and infrastructure to pass filesystem
health events to a health monitoring file.  Since this is an
administrative interface, we only support a single health monitor
process per filesystem, so we don't need to use anything fancy such as
notifier chains (== tons of indirect calls).

Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

diff --git a/libxfs/xfs_fs.h b/libxfs/xfs_fs.h
index 12463ba766da053530e19b34c6a8344c67da3cd8..c58e55b3df409960310c32d4378e7d228d6c27e7 100644 (file)
--- a/libxfs/xfs_fs.h
+++ b/libxfs/xfs_fs.h
@@ -1003,6 +1003,12 @@ struct xfs_rtgroup_geometry {
 #define XFS_RTGROUP_GEOM_SICK_RMAPBT   (1U << 3)  /* reverse mappings */
 #define XFS_RTGROUP_GEOM_SICK_REFCNTBT (1U << 4)  /* reference counts */
 
+struct xfs_health_monitor {
+       __u64   flags;          /* flags */
+       __u8    format;         /* output format */
+       __u8    pad[23];        /* zeroes */
+};
+
 /*
  * ioctl commands that are used by Linux filesystems
  */
@@ -1042,6 +1048,7 @@ struct xfs_rtgroup_geometry {
 #define XFS_IOC_GETPARENTS_BY_HANDLE _IOWR('X', 63, struct xfs_getparents_by_handle)
 #define XFS_IOC_SCRUBV_METADATA        _IOWR('X', 64, struct xfs_scrub_vec_head)
 #define XFS_IOC_RTGROUP_GEOMETRY _IOWR('X', 65, struct xfs_rtgroup_geometry)
+#define XFS_IOC_HEALTH_MONITOR _IOW ('X', 68, struct xfs_health_monitor)
 
 /*
  * ioctl commands that replace IRIX syssgi()'s