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/ocfs2/file.c b/fs/ocfs2/file.c
index d631279..7cb38fd 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -1872,7 +1872,7 @@
 	if (ocfs2_is_hard_readonly(osb) || ocfs2_is_soft_readonly(osb))
 		return -EROFS;
 
-	mutex_lock(&inode->i_mutex);
+	inode_lock(inode);
 
 	/*
 	 * This prevents concurrent writes on other nodes
@@ -1991,7 +1991,7 @@
 	ocfs2_rw_unlock(inode, 1);
 
 out:
-	mutex_unlock(&inode->i_mutex);
+	inode_unlock(inode);
 	return ret;
 }
 
@@ -2299,7 +2299,7 @@
 	appending = iocb->ki_flags & IOCB_APPEND ? 1 : 0;
 	direct_io = iocb->ki_flags & IOCB_DIRECT ? 1 : 0;
 
-	mutex_lock(&inode->i_mutex);
+	inode_lock(inode);
 
 relock:
 	/*
@@ -2435,7 +2435,7 @@
 		ocfs2_rw_unlock(inode, rw_level);
 
 out_mutex:
-	mutex_unlock(&inode->i_mutex);
+	inode_unlock(inode);
 
 	if (written)
 		ret = written;
@@ -2547,7 +2547,7 @@
 	struct inode *inode = file->f_mapping->host;
 	int ret = 0;
 
-	mutex_lock(&inode->i_mutex);
+	inode_lock(inode);
 
 	switch (whence) {
 	case SEEK_SET:
@@ -2585,7 +2585,7 @@
 	offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
 
 out:
-	mutex_unlock(&inode->i_mutex);
+	inode_unlock(inode);
 	if (ret)
 		return ret;
 	return offset;