[Libsysio-commit] HEAD: libsysio/include inode.h

[Lee W. <lw...@us...>]

Update of /cvsroot/libsysio/libsysio/include
In directory ddv4jf1.ch3.sourceforge.com:/tmp/cvs-serv15278/include

Modified Files:
	inode.h 
Log Message:


With I_ASSOCIATIONS defined, inodes keep a list of all path-base
nodes that are currently associated.

Always, association of a path-base node with an i-node is now done via
the macro PB_SET_ASSOC(). This, new, macro will not allow an already
associated path-base node to gain a new association; This to enforce
the emerging policy of "once set, immutable" for these nodes. You can
set the association of an unassociated path-base node or clear it, only.


Index: inode.h
===================================================================
RCS file: /cvsroot/libsysio/libsysio/include/inode.h,v
retrieving revision 1.48
retrieving revision 1.49
diff -u -w -b -B -p -r1.48 -r1.49
--- inode.h	5 Jan 2009 19:19:29 -0000	1.48
+++ inode.h	22 Jan 2009 19:07:42 -0000	1.49
@@ -139,10 +139,22 @@ struct inode {
     struct inode_ops i_ops;                             /* operations */
     struct intnl_stat i_stbuf;				/* attrs */
     struct filesys *i_fs;                               /* file system ptr */
+#ifdef I_ASSOCIATIONS
+    LIST_HEAD(, pnode_base) i_assoc;                    /* assoc'd pbnodes */
+#endif
     void    *i_private;                                 /* driver data */
     TAILQ_ENTRY(inode) i_nodes;                         /* all i-nodes link */
 };
 
+#ifdef I_ASSOCIATIONS
+#define _I_INIT_MORE(_ino) \
+    do { \
+        LIST_INIT(&(_ino)->i_assoc); \
+    } while (0)
+#else
+#define _I_INIT_MORE(_ino)
+#endif
+
 /*
  * Init an i-node record.
  */
@@ -160,6 +172,7 @@ struct inode {
         (ino)->i_stbuf = *(stat); \
         (ino)->i_fs = (fs); \
         (ino)->i_private = (private); \
+        _I_INIT_MORE(ino); \
     } while (0)
 
 #ifdef LOCK_DEBUG
@@ -248,6 +261,20 @@ struct inode {
     } while (0)
 
 /*
+ * Check association; Logical true if so, otherwise false.
+ *
+ * NB: The given i-node should be locked or otherwise protected from
+ * manipulation by others.
+ */
+#ifdef I_ASSOCIATIONS
+#define I_ISASSOC(_ino) \
+    ((_ino)->i_assoc.lh_first)
+#else
+#define I_ISASSOC(_ino) \
+    (0)
+#endif
+
+/*
  * The "quick string" record (inspired by the structure of the same name
  * from Linux) is used to pass a string without delimiters as well as useful
  * information about the string.
@@ -276,6 +303,9 @@ struct pnode_base {
     LIST_HEAD(, pnode_base) pb_children;                /* children if a dir */
     LIST_ENTRY(pnode_base) pb_sibs;                     /* links to siblings */
     LIST_HEAD(, pnode) pb_aliases;                      /* aliases */
+#ifdef I_ASSOCIATIONS
+    LIST_ENTRY(pnode_base) pb_alinks;                   /* names to same ino */
+#endif
 #ifdef PB_DEBUG
     TAILQ_ENTRY(pnode_base) pb_links;                   /* leaf pbnodes links */
 #endif
@@ -284,7 +314,7 @@ struct pnode_base {
 /*
  * Init a path-base record.
  */
-#define PB_INIT(_pb, _name, _parent, _ino) \
+#define PB_INIT(_pb, _name, _parent) \
 	do { \
 		mutex_init(&(_pb)->pb_mutex, MUTEX_RECURSIVE); \
 		(_pb)->pb_lckcnt = 0; \
@@ -293,7 +323,7 @@ struct pnode_base {
 		(_pb)->pb_tentry.tn_left = (_pb)->pb_tentry.tn_right = NULL; \
 		(_pb)->pb_key.pbk_name = *(_name); \
 		(_pb)->pb_key.pbk_parent = (_parent); \
-		(_pb)->pb_ino = (_ino); \
+		(_pb)->pb_ino = NULL; \
 		LIST_INIT(&(_pb)->pb_children); \
 		LIST_INIT(&(_pb)->pb_aliases); \
 	} while (0)
@@ -342,6 +372,42 @@ struct pnode_base {
     } while (0)
 
 /*
+ * Set path-base node association.
+ *
+ * NB: All of the path-base node, any i-node it currently points at, and
+ * the new i-node must be locked. If the path-base node is associated,
+ * the association will be removed before making the new but it will not be
+ * released, unlocked, or dereferenced.
+ *
+ * NB(2): We no longer support re-association. Now, an association can be
+ * set, anew, or cleared (only when destroying the path-base node.
+ */
+#ifdef I_ASSOCIATIONS
+#define PB_SET_ASSOC(_pb, _ino) \
+	do { \
+		_PB_CHECK_LOCK((_pb), 1); \
+		if ((_pb)->pb_ino) { \
+			assert(!(_ino)); \
+			_I_CHECK_LOCK((_pb)->pb_ino, 1); \
+			LIST_REMOVE((_pb), pb_alinks); \
+		} \
+		(_pb)->pb_ino = (_ino); \
+		if ((_pb)->pb_ino) { \
+			_I_CHECK_LOCK((_pb)->pb_ino, 1); \
+			LIST_INSERT_HEAD(&(_pb)->pb_ino->i_assoc, \
+					 (_pb), \
+					 pb_alinks); \
+		} \
+	} while (0)
+#else
+#define PB_SET_ASSOC(_pb, _ino) \
+	do { \
+		assert(!((_pb)->pb_ino && (_ino))); \
+		(_pb)->pb_ino = (_ino); \
+	} while (0)
+#endif
+
+/*
  * Since a file system may be multiply mounted, in different parts of the local
  * tree, a file system object may appear in different places. We handle that
  * with aliases. There is one pnode for every alias the system is tracking.