On Tue, Jan 09, 2024 at 09:55:24AM +0000, John Garry wrote: > So a user can issue: > > >xfs_io -c "atomic-writes 64K" mnt/file > >xfs_io -c "atomic-writes" mnt/file > [65536] mnt/file Let me try to decipher that: - the first call sets a 64k fsx_atomicwrites_size size - the secon call queries fsx_atomicwrites_size? > The user will still have to issue statx to get the actual atomic write > limit for a file, as 'xfs_io -c "atomic-writes"' does not take into account > any HW/linux block layer atomic write limits. So will the set side never fail? > Is this the sort of userspace API which you would like to see? What I had in mind (and that's doesn't mean it's right..) was that the user just sets a binary flag, and the fs reports the best it could. But there might be reasons to do it differently.