On Fri, Apr 04, 2025 at 10:36:32AM +0100, John Garry wrote: > > @@ -243,6 +243,11 @@ The fields are as follows: > > regular file data. > > This is only useful for FIEMAP. > > + * **IOMAP_F_BOUNDARY**: This indicates that I/O and I/O completions > > + for this iomap must never be merged with the mapping before it. > > This is just effectively the same comment as in the code - what's the use in > this? Darrick asked for this file to have full comments. I'm more on your side here as a lot of this seem redundant. > > > + Currently XFS uses this to prevent merging of ioends across RTG > > + (realtime group) boundaries. > > + > > * **IOMAP_F_PRIVATE**: Starting with this value, the upper bits can > > be set by the filesystem for its own purposes. > > Is this comment now out of date according to your change in 923936efeb74? Also we probably should not detail file system behavior here, but a high level description of what it is useful.