keep track of whether the union node is cached or not.

[unix-history] / usr / src / sys / miscfs / union / union_subr.c

diff --git a/usr/src/sys/miscfs/union/union_subr.c b/usr/src/sys/miscfs/union/union_subr.c
index f0cd58e..1149caa 100644 (file)
--- a/usr/src/sys/miscfs/union/union_subr.c
+++ b/usr/src/sys/miscfs/union/union_subr.c
@@ -8,7 +8,7 @@
  *
  * %sccs.include.redist.c%
  *
  *
  * %sccs.include.redist.c%
  *

- *     @(#)union_subr.c        8.5 (Berkeley) %G%
+ *     @(#)union_subr.c        8.6 (Berkeley) %G%

  */
 
 #include <sys/param.h>
  */
 
 #include <sys/param.h>


@@ -85,31 +85,35 @@ union_updatevp(un, uppervp, lowervp)
 {
        int ohash = UNION_HASH(un->un_uppervp, un->un_lowervp);
        int nhash = UNION_HASH(uppervp, lowervp);
 {
        int ohash = UNION_HASH(un->un_uppervp, un->un_lowervp);
        int nhash = UNION_HASH(uppervp, lowervp);

+       int docache = (lowervp != NULLVP || uppervp != NULLVP);

 
 

-       if (ohash != nhash) {
-               /*
-                * Ensure locking is ordered from lower to higher
-                * to avoid deadlocks.
-                */
-               if (nhash < ohash) {
-                       int t = ohash;
-                       ohash = nhash;
-                       nhash = t;
-               }
+       /*
+        * Ensure locking is ordered from lower to higher
+        * to avoid deadlocks.
+        */
+       if (nhash < ohash) {
+               int t = ohash;
+               ohash = nhash;
+               nhash = t;
+       }

 
 

+       if (ohash != nhash)

                while (union_list_lock(ohash))
                        continue;
 
                while (union_list_lock(ohash))
                        continue;
 

-               while (union_list_lock(nhash))
-                       continue;
+       while (union_list_lock(nhash))
+               continue;

 
 

-               LIST_REMOVE(un, un_cache);
-               union_list_unlock(ohash);
-       } else {        
-               while (union_list_lock(nhash))
-                       continue;
+       if (ohash != nhash || !docache) {
+               if (un->un_flags & UN_CACHED) {
+                       LIST_REMOVE(un, un_cache);
+                       un->un_flags &= ~UN_CACHED;
+               }

        }
 
        }
 

+       if (ohash != nhash)
+               union_list_unlock(ohash);
+

        if (un->un_lowervp != lowervp) {
                if (un->un_lowervp) {
                        vrele(un->un_lowervp);
        if (un->un_lowervp != lowervp) {
                if (un->un_lowervp) {
                        vrele(un->un_lowervp);


@@ -132,8 +136,10 @@ union_updatevp(un, uppervp, lowervp)
                un->un_uppervp = uppervp;
        }
 
                un->un_uppervp = uppervp;
        }
 

-       if (ohash != nhash)
+       if (docache && (ohash != nhash)) {

                LIST_INSERT_HEAD(&unhead[nhash], un, un_cache);
                LIST_INSERT_HEAD(&unhead[nhash], un, un_cache);

+               un->un_flags |= UN_CACHED;
+       }

 
        union_list_unlock(nhash);
 }
 
        union_list_unlock(nhash);
 }


@@ -417,6 +423,7 @@ loop:
        }
 
        LIST_INSERT_HEAD(&unhead[hash], un, un_cache);
        }
 
        LIST_INSERT_HEAD(&unhead[hash], un, un_cache);

+       un->un_flags |= UN_CACHED;

 
        if (xlowervp)
                vrele(xlowervp);
 
        if (xlowervp)
                vrele(xlowervp);


@@ -433,13 +440,16 @@ union_freevp(vp)
 {
        struct union_node *un = VTOUNION(vp);
 
 {
        struct union_node *un = VTOUNION(vp);
 

-       LIST_REMOVE(un, un_cache);
+       if (un->un_flags & UN_CACHED) {
+               LIST_REMOVE(un, un_cache);
+               un->un_flags &= ~UN_CACHED;
+       }

 
 

-       if (un->un_uppervp)
+       if (un->un_uppervp != NULLVP)

                vrele(un->un_uppervp);
                vrele(un->un_uppervp);

-       if (un->un_lowervp)
+       if (un->un_lowervp != NULLVP)

                vrele(un->un_lowervp);
                vrele(un->un_lowervp);

-       if (un->un_dirvp)
+       if (un->un_dirvp != NULLVP)

                vrele(un->un_dirvp);
        if (un->un_path)
                free(un->un_path, M_TEMP);
                vrele(un->un_dirvp);
        if (un->un_path)
                free(un->un_path, M_TEMP);