inode: draft code for sleeping file system support

diff --git a/Kernel/inode.c b/Kernel/inode.c
index 57c4ad3..438cd67 100644 (file)
--- a/Kernel/inode.c
+++ b/Kernel/inode.c
@@ -386,3 +386,53 @@ void sync(void)
        /* WRS: also call d_flush(dev) here for each dirty dev ? */
        bufsync();              /* Clear buffer pool */
 }
+
+#ifdef CONFIG_BLOCK_SLEEP
+
+/* ptab is an array so won't exceed 64K so this crude cast works nicely */
+
+static void i_lock(struct inode *i)
+{
+       if (i->lock == (uint16_t)udata.u_ptab)
+               panic(LOCKLOCK);
+       while(i->i_lock)
+               psleep_nosig(i);
+       i->i_lock = (uint16_t)udata.u_ptab;
+}
+
+static void i_unlock(struct inode *i)
+{
+       i_islocked(i);
+       i->i_lock = 0;
+       pwakeup_nosig(i);
+}
+
+static void i_unlock_deref(struct inode *i)
+{
+       i->i_lock = 0;
+       i_deref(i);
+}
+
+void i_islocked(struct inode *i)
+{
+       if (i->lock != (uint16_t)udata.u_ptab)
+               panic(IUNLOCK);
+}
+
+struct inode *n_open_lock(char *uname, struct inode **parent)
+{
+       struct inode *i = n_open(uname, parent);
+       if (i)
+               i_lock(i);
+       return i;
+}
+
+struct inode *getinode_lock(uint8_t uindex)
+{
+       struct inode *i = getinode(uindex);
+       if (i)
+               i_lock(i);
+       return i;
+}
+
+#endif