On Tue, Jul 16, 2024 at 06:46:40PM +0100, Matthew Wilcox wrote: > On Tue, Jul 16, 2024 at 10:40:16AM -0700, Darrick J. Wong wrote: > > On Tue, Jul 16, 2024 at 04:29:05PM +0100, Matthew Wilcox wrote: > > > On Mon, Jul 15, 2024 at 11:44:57AM +0200, Pankaj Raghav (Samsung) wrote: > > > > +++ b/fs/xfs/xfs_super.c > > > > @@ -1638,16 +1638,30 @@ xfs_fs_fill_super( > > > > goto out_free_sb; > > > > } > > > > > > > > - /* > > > > - * Until this is fixed only page-sized or smaller data blocks work. > > > > - */ > > > > if (mp->m_sb.sb_blocksize > PAGE_SIZE) { > > > > - xfs_warn(mp, > > > > - "File system with blocksize %d bytes. " > > > > - "Only pagesize (%ld) or less will currently work.", > > > > + size_t max_folio_size = mapping_max_folio_size_supported(); > > > > + > > > > + if (!xfs_has_crc(mp)) { > > > > + xfs_warn(mp, > > > > +"V4 Filesystem with blocksize %d bytes. Only pagesize (%ld) or less is supported.", > > > > mp->m_sb.sb_blocksize, PAGE_SIZE); > > > > - error = -ENOSYS; > > > > - goto out_free_sb; > > > > + error = -ENOSYS; > > > > + goto out_free_sb; > > > > + } > > > > + > > > > + if (mp->m_sb.sb_blocksize > max_folio_size) { > > > > + xfs_warn(mp, > > > > +"block size (%u bytes) not supported; maximum folio size supported in "\ > > > > +"the page cache is (%ld bytes). Check MAX_PAGECACHE_ORDER (%d)", > > > > + mp->m_sb.sb_blocksize, max_folio_size, > > > > + MAX_PAGECACHE_ORDER); > > > > > > Again, too much message. Way too much. We shouldn't even allow block > > > devices to be created if their block size is larger than the max supported > > > by the page cache. > > > > Filesystem blocksize != block device blocksize. xfs still needs this > > check because one can xfs_copy a 64k-fsblock xfs to a hdd with 512b > > sectors and try to mount that on x86. > > > > Assuming there /is/ some fs that allows 1G blocksize, you'd then really > > want a mount check that would prevent you from mounting that. > > Absolutely, we need to have an fs blocksize check in the fs (if only > because fs fuzzers will put random values in fields and expect the system > to not crash). But that should have nothing to do with page cache size. I don't understand your objection -- we're setting the minimum folio order on a file's pagecache to match the fs-wide blocksize. If the pagecache can't possibly fulfill our fs-wide requirement, then why would we continue the mount? Let's pretend that MAX_PAGECACHE_ORDER is 1. The filesystem has 16k blocks, the CPU has 4k base pages. xfs will try to set the min folio order to 2 via mapping_set_folio_order_range. That function clamps it to 1, so we try to cache a 16k fsblock with 8k pages. Does that actually work? If not, then doesn't it make more more sense to fail the mount? --D