Re: [PATCH 0/7] RFC: high-order folio support for I/O

[Hannes Reinecke <hare@suse.de>]

On 6/14/23 13:46, Hannes Reinecke wrote:
> Hi all,
> 
> now, that was easy.
> Thanks to willy and his recent patchset to support large folios in
> gfs2 turns out that most of the work to support high-order folios
> for I/O is actually done.
> It only need twe rather obvious patches to allocate folios with
> the order derived from the mapping blocksize, and to adjust readahead
> to avoid reading off the end of the device.
> But with these two patches (and the patchset from hch to switch
> the block device over to iomap) (and the patchset from ritesh to
> support sub-blocksize iomap buffers) I can now do:
> 
> # modprobe brd rd_size=524288 rd_blksize=16384
> # mkfs.xfs -b size=16384 /dev/ram0
> 
> it still fails when trying to mount the device:
> 
> XFS (ram0): Cannot set_blocksize to 16384 on device ram0
> 
> but to my understanding this is being worked on.
> 
Turns out that was quite easy to fix (just remove the check in 
set_blocksize()), but now I get this:

SGI XFS with ACLs, security attributes, quota, no debug enabled
XFS (ram0): File system with blocksize 16384 bytes. Only pagesize (4096) 
or less will currently work.

Hmm. And btrfs doesn't fare better here:

BTRFS info (device ram0): using crc32c (crc32c-intel) checksum algorithm
BTRFS error (device ram0): sectorsize 16384 not yet supported for page 
size 4096
BTRFS error (device ram0): superblock contains fatal errors
BTRFS error (device ram0): open_ctree failed

But at least we _can_ test these filesystems now :-)

Cheers,

Hannes