On Fri, Aug 08, 2025 at 06:20:56PM +0930, Qu Wenruo wrote: > > 在 2025/8/8 17:22, Qu Wenruo 写道: > > Hi, > > > > [BACKGROUND] > > Recently I'm testing btrfs with 16KiB block size. > > > > Currently btrfs is artificially limiting subpage block size to 4K. > > But there is a simple patch to change it to support all block sizes <= > > page size in my branch: > > > > https://github.com/adam900710/linux/tree/larger_bs_support > > > > [IOMAP WARNING] > > And I'm running into a very weird kernel warning at btrfs/136, with 16K > > block size and 64K page size. > > > > The problem is, the problem happens with ext3 (using ext4 modeule) with > > 16K block size, and no btrfs is involved yet. Thanks for the bug report! This looks like it's an issue with using indirect block-mapped file with a 16k block size. I tried your reproducer using a 1k block size on an x86_64 system, which is how I test problem caused by the block size < page size. It didn't reproduce there, so it looks like it really needs a 16k block size. Can you say something about what system were you running your testing on --- was it an arm64 system, or a powerpc 64 system (the two most common systems with page size > 4k)? (I assume you're not trying to do this on an Itanic. :-) And was the page size 16k or 64k? Thanks, - Ted
