wrappers for ->i_mutex access

parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested},
inode_foo(inode) being mutex_foo(&inode->i_mutex).

Please, use those for access to ->i_mutex; over the coming cycle
->i_mutex will become rwsem, with ->lookup() done with it held
only shared.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c
index be6d9c4..a398913 100644
--- a/fs/gfs2/quota.c
+++ b/fs/gfs2/quota.c
@@ -888,7 +888,7 @@
 		return -ENOMEM;
 
 	sort(qda, num_qd, sizeof(struct gfs2_quota_data *), sort_qd, NULL);
-	mutex_lock(&ip->i_inode.i_mutex);
+	inode_lock(&ip->i_inode);
 	for (qx = 0; qx < num_qd; qx++) {
 		error = gfs2_glock_nq_init(qda[qx]->qd_gl, LM_ST_EXCLUSIVE,
 					   GL_NOCACHE, &ghs[qx]);
@@ -953,7 +953,7 @@
 out:
 	while (qx--)
 		gfs2_glock_dq_uninit(&ghs[qx]);
-	mutex_unlock(&ip->i_inode.i_mutex);
+	inode_unlock(&ip->i_inode);
 	kfree(ghs);
 	gfs2_log_flush(ip->i_gl->gl_name.ln_sbd, ip->i_gl, NORMAL_FLUSH);
 	return error;
@@ -1674,7 +1674,7 @@
 	if (error)
 		goto out_put;
 
-	mutex_lock(&ip->i_inode.i_mutex);
+	inode_lock(&ip->i_inode);
 	error = gfs2_glock_nq_init(qd->qd_gl, LM_ST_EXCLUSIVE, 0, &q_gh);
 	if (error)
 		goto out_unlockput;
@@ -1739,7 +1739,7 @@
 out_q:
 	gfs2_glock_dq_uninit(&q_gh);
 out_unlockput:
-	mutex_unlock(&ip->i_inode.i_mutex);
+	inode_unlock(&ip->i_inode);
 out_put:
 	qd_put(qd);
 	return error;