Since commit 
a2ad63daa88b ("VFS: add FMODE_CAN_ODIRECT file flag") file
systems can just set the FMODE_CAN_ODIRECT flag at open time instead of
wiring up a dummy direct_IO method to indicate support for direct I/O.
Do that for btrfs so that noop_direct_IO can eventually be removed.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
 {
        int ret;
 
-       filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC | FMODE_BUF_WASYNC;
+       filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC | FMODE_BUF_WASYNC |
+                       FMODE_CAN_ODIRECT;
 
        ret = fsverity_file_open(inode, filp);
        if (ret)
 
        .read_folio     = btrfs_read_folio,
        .writepages     = btrfs_writepages,
        .readahead      = btrfs_readahead,
-       .direct_IO      = noop_direct_IO,
        .invalidate_folio = btrfs_invalidate_folio,
        .release_folio  = btrfs_release_folio,
        .migrate_folio  = btrfs_migrate_folio,