xfs: kill xfs_qmops

Kill the quota ops function vector and replace it with direct calls or
stubs in the CONFIG_XFS_QUOTA=n case.

Make sure we check XFS_IS_QUOTA_RUNNING in the right spots.  We can remove
the number of those checks because the XFS_TRANS_DQ_DIRTY flag can't be set
otherwise.

This brings us back closer to the way this code worked in IRIX and earlier
Linux versions, but we keep a lot of the more useful factoring of common
code.

Eventually we should also kill xfs_qm_bhv.c, but that's left for a later
patch.

Reduces the size of the source code by about 250 lines and the size of
XFS module by about 1.5 kilobytes with quotas enabled:

   text	   data	    bss	    dec	    hex	filename
 615957	   2960	   3848	 622765	  980ad	fs/xfs/xfs.o
 617231	   3152	   3848	 624231	  98667	fs/xfs/xfs.o.old

Fallout:

 - xfs_qm_dqattach is split into xfs_qm_dqattach_locked which expects
   the inode locked and xfs_qm_dqattach which does the locking around it,
   thus removing XFS_QMOPT_ILOCKED.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Eric Sandeen <sandeen@sandeen.net>
diff --git a/fs/xfs/xfs_bmap_btree.c b/fs/xfs/xfs_bmap_btree.c
index 0760d35..5c1ade0 100644
--- a/fs/xfs/xfs_bmap_btree.c
+++ b/fs/xfs/xfs_bmap_btree.c
@@ -590,7 +590,7 @@
 	cur->bc_private.b.allocated++;
 	cur->bc_private.b.ip->i_d.di_nblocks++;
 	xfs_trans_log_inode(args.tp, cur->bc_private.b.ip, XFS_ILOG_CORE);
-	XFS_TRANS_MOD_DQUOT_BYINO(args.mp, args.tp, cur->bc_private.b.ip,
+	xfs_trans_mod_dquot_byino(args.tp, cur->bc_private.b.ip,
 			XFS_TRANS_DQ_BCOUNT, 1L);
 
 	new->l = cpu_to_be64(args.fsbno);
@@ -618,7 +618,7 @@
 	ip->i_d.di_nblocks--;
 
 	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
-	XFS_TRANS_MOD_DQUOT_BYINO(mp, tp, ip, XFS_TRANS_DQ_BCOUNT, -1L);
+	xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, -1L);
 	xfs_trans_binval(tp, bp);
 	return 0;
 }