Index: configure
===================================================================
RCS file: /projects/cvsroot/pvfs2/configure,v
retrieving revision 1.367
diff -u -a -p -r1.367 configure
--- configure	9 Nov 2007 00:10:20 -0000	1.367
+++ configure	15 Nov 2007 18:26:41 -0000
@@ -11440,6 +11440,62 @@ fi
 
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
+	cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+		#define __KERNEL__
+		#include <linux/fs.h>
+
+int
+main ()
+{
+
+		struct address_space as;
+		spin_lock(&as.page_lock);
+
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext
+if { (ac_try="$ac_compile"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_compile") 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } && {
+	 test -z "$ac_c_werror_flag" ||
+	 test ! -s conftest.err
+       } && test -s conftest.$ac_objext; then
+  { echo "$as_me:$LINENO: result: yes" >&5
+echo "${ECHO_T}yes" >&6; }
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_SPIN_LOCK_ADDR_SPACE_STRUCT 1
+_ACEOF
+
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+	{ echo "$as_me:$LINENO: result: no" >&5
+echo "${ECHO_T}no" >&6; }
+
+fi
+
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+
 	CFLAGS=$oldcflags
 
 
Index: pvfs2-config.h.in
===================================================================
RCS file: /projects/cvsroot/pvfs2/pvfs2-config.h.in,v
retrieving revision 1.111
diff -u -a -p -r1.111 pvfs2-config.h.in
--- pvfs2-config.h.in	5 Nov 2007 21:07:54 -0000	1.111
+++ pvfs2-config.h.in	15 Nov 2007 18:26:41 -0000
@@ -273,6 +273,9 @@
 /* Define if SLAB_KERNEL is defined in kernel */
 #undef HAVE_SLAB_KERNEL
 
+/* Define if kernel address_space struct has a spin_lock instead of rw_lock */
+#undef HAVE_SPIN_LOCK_ADDR_SPACE_STRUCT
+
 /* Define if struct super_operations in kernel has statfs_lite callback */
 #undef HAVE_STATFS_LITE_SUPER_OPERATIONS
 
Index: maint/config/kernel.m4
===================================================================
RCS file: /projects/cvsroot/pvfs2/maint/config/kernel.m4,v
retrieving revision 1.46
diff -u -a -p -r1.46 kernel.m4
--- maint/config/kernel.m4	6 Nov 2007 16:29:52 -0000	1.46
+++ maint/config/kernel.m4	15 Nov 2007 18:26:41 -0000
@@ -849,5 +849,17 @@ AC_DEFUN([AX_KERNEL_FEATURES],
 	AC_MSG_RESULT(no)
 	)
 
+	AC_TRY_COMPILE([
+		#define __KERNEL__
+		#include <linux/fs.h>
+	], [
+		struct address_space as;
+		spin_lock(&as.page_lock);
+	],
+	AC_MSG_RESULT(yes)
+	AC_DEFINE(HAVE_SPIN_LOCK_ADDR_SPACE_STRUCT, 1, [Define if kernel address_space struct has a spin_lock instead of rw_lock]),
+	AC_MSG_RESULT(no)
+	)
+
 	CFLAGS=$oldcflags
 ])
Index: src/kernel/linux-2.6/file.c
===================================================================
RCS file: /projects/cvsroot/pvfs2/src/kernel/linux-2.6/file.c,v
retrieving revision 1.141
diff -u -a -p -r1.141 file.c
--- src/kernel/linux-2.6/file.c	31 Aug 2007 22:20:49 -0000	1.141
+++ src/kernel/linux-2.6/file.c	15 Nov 2007 18:26:42 -0000
@@ -772,6 +772,14 @@ static int pvfs2_readpages_fill_cb(void 
     return 0;
 }
 
+#ifdef HAVE_SPIN_LOCK_ADDR_SPACE_STRUCT
+#define lock_page_tree(mapping) spin_lock(&mapping->page_lock)
+#define unlock_page_tree(mapping) spin_unlock(&mapping->page_lock)
+#else
+#define lock_page_tree(mapping) read_lock_irq(&mapping->tree_lock)
+#define unlock_page_tree(mapping) read_unlock_irq(&mapping->tree_lock)
+#endif
+
 /* A debugging function to check the contents of a
  *  mapping's address space/radix tree
  */
@@ -785,7 +793,7 @@ static int check_mapping_tree(struct add
     begin_index = 0;
     end_index = (file_size - 1) >> PAGE_CACHE_SHIFT;
     nr_to_read = end_index - begin_index + 1;
-    read_lock_irq(&mapping->tree_lock);
+    lock_mapping_tree(mapping);
     for (page_idx = 0; page_idx < nr_to_read; page_idx++) {
         struct page *page;
         pgoff_t page_offset = begin_index + page_idx;
@@ -805,7 +813,7 @@ static int check_mapping_tree(struct add
                                             page_idx, page_offset);
         }
     }
-    read_unlock_irq(&mapping->tree_lock);
+    unlock_mapping_tree(mapping);
     return 0;
 }
                             
@@ -877,7 +885,7 @@ static int locate_file_pages(struct rw_o
     gossip_debug(GOSSIP_FILE_DEBUG, "read %ld pages\n",
             nr_to_read);
 
-    read_lock_irq(&mapping->tree_lock);
+    lock_mapping_tree(mapping);
     /* Preallocate all pages, increase their ref counts if they are in cache */
     for (page_idx = 0; page_idx < nr_to_read; page_idx++) {
         pgoff_t page_offset = begin_index + page_idx;
@@ -898,10 +906,10 @@ static int locate_file_pages(struct rw_o
             continue;
         }
         g_pvfs2_stats.cache_misses++;
-        read_unlock_irq(&mapping->tree_lock);
+        unlock_mapping_tree(mapping);
         /* Allocate, but don't add it to the LRU list yet */
         page = page_cache_alloc_cold(mapping);
-        read_lock_irq(&mapping->tree_lock);
+        lock_mapping_tree(mapping);
         if (!page) {
             ret = -ENOMEM;
             gossip_err("could not allocate page cache\n");
@@ -921,7 +929,7 @@ static int locate_file_pages(struct rw_o
         rw->dest.pages.pg_byte_map[page_idx] = 1;
         ret++;
     }
-    read_unlock_irq(&mapping->tree_lock);
+    unlock_mapping_tree(mapping);
     /* cleanup in case of error */
     if (ret < 0) {
         gossip_err("could not page_cache_alloc_cold\n");