xfs: switch to NOFS allocation under i_lock in xfs_dir_cilookup_result

xfs_dir_cilookup_result 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_dir2.c

···
 					!(args->op_flags & XFS_DA_OP_CILOOKUP))
 		return EEXIST;
 
-	args->value = kmem_alloc(len, KM_MAYFAIL);
+	args->value = kmem_alloc(len, KM_NOFS | KM_MAYFAIL);
 	if (!args->value)
 		return ENOMEM;