xfs: switch to NOFS allocation under i_lock in xfs_da_state_alloc

xfs_da_state_alloc is always called with i_lock held, but i_lock is taken in
reclaim context so all allocations under it must avoid recursions into the
filesystem.

Reported by the new reclaim context tracing in lockdep.

Signed-off-by: Christoph Hellwig <[e-mail]>
Reviewed-by: Felix Blyakher <[e-mail]>
Signed-off-by: Felix Blyakher <[e-mail]>

fs/xfs/xfs_da_btree.c

···
 xfs_da_state_t *
 xfs_da_state_alloc(void)
 {
-	return kmem_zone_zalloc(xfs_da_state_zone, KM_SLEEP);
+	return kmem_zone_zalloc(xfs_da_state_zone, KM_NOFS);
 }
 
 /*