On Thu, Mar 20, 2025 at 09:19:40AM +0000, John Garry wrote: > But is there value in reporting this limit? I am not sure. I am not sure > what the user would do with this info. Align their data structures to it, e.g. size the log buffers to it. > Maybe, for example, they want to write 1K consecutive 16K pages, each > atomically, and decide to do a big 16M atomic write but find that it is > slow as bdev atomic limit is < 16M. > > Maybe I should just update the documentation to mention that for XFS they > should check the mounted bdev atomic limits. For something working on files having to figure out the underlying block device (which is non-trivial given the various methods of multi-device support) and then looking into block sysfs is a no-go. So if we have any sort of use case for it we should expose the limit.