Linux 3.4 compat, d_make_root() replaces d_alloc_root()

torvalds/linux@adc0e91ab142abe93f5b0d7980ada8a7676231fe introduced
introduced d_make_root() as a replacement for d_alloc_root(). Further
commits appear to have removed d_alloc_root() from the Linux source
tree. This causes the following failure:

  error: implicit declaration of function 'd_alloc_root'
  [-Werror=implicit-function-declaration]

To correct this we update the code to use the current d_make_root()
interface for readability.  Then we introduce an autotools check
to determine if d_make_root() is available.  If it isn't then we
define some compatibility logic which used the older d_alloc_root()
interface.

Signed-off-by: Richard Yao <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>
Closes #776

1 files changed, 106 insertions, 0 deletions

diff --git a/configure b/configure
index a8e7cb711..f46d147c7 100755
--- a/configure
+++ b/configure
@@ -15945,6 +15945,59 @@ fi
 
 
 
+	{ $as_echo "$as_me:$LINENO: checking whether symbol d_make_root is exported" >&5
+$as_echo_n "checking whether symbol d_make_root is exported... " >&6; }
+	grep -q -E '[[:space:]]d_make_root[[:space:]]' \
+		$LINUX_OBJ/$LINUX_SYMBOLS 2>/dev/null
+	rc=$?
+	if test $rc -ne 0; then
+
+		export=0
+		for file in fs/dcache.c; do
+			grep -q -E "EXPORT_SYMBOL.*(d_make_root)" "$LINUX/$file" 2>/dev/null
+			rc=$?
+			if test $rc -eq 0; then
+
+				export=1
+				break;
+
+fi
+
+		done
+		if test $export -eq 0; then
+
+			{ $as_echo "$as_me:$LINENO: result: no" >&5
+$as_echo "no" >&6; }
+
+
+else
+
+			{ $as_echo "$as_me:$LINENO: result: yes" >&5
+$as_echo "yes" >&6; }
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_D_MAKE_ROOT 1
+_ACEOF
+
+
+fi
+
+
+else
+
+		{ $as_echo "$as_me:$LINENO: result: yes" >&5
+$as_echo "yes" >&6; }
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_D_MAKE_ROOT 1
+_ACEOF
+
+
+fi
+
+
+
+
 	{ $as_echo "$as_me:$LINENO: checking whether symbol d_obtain_alias is exported" >&5
 $as_echo_n "checking whether symbol d_obtain_alias is exported... " >&6; }
 	grep -q -E '[[:space:]]d_obtain_alias[[:space:]]' \
@@ -22040,6 +22093,59 @@ fi
 
 
 
+	{ $as_echo "$as_me:$LINENO: checking whether symbol d_make_root is exported" >&5
+$as_echo_n "checking whether symbol d_make_root is exported... " >&6; }
+	grep -q -E '[[:space:]]d_make_root[[:space:]]' \
+		$LINUX_OBJ/$LINUX_SYMBOLS 2>/dev/null
+	rc=$?
+	if test $rc -ne 0; then
+
+		export=0
+		for file in fs/dcache.c; do
+			grep -q -E "EXPORT_SYMBOL.*(d_make_root)" "$LINUX/$file" 2>/dev/null
+			rc=$?
+			if test $rc -eq 0; then
+
+				export=1
+				break;
+
+fi
+
+		done
+		if test $export -eq 0; then
+
+			{ $as_echo "$as_me:$LINENO: result: no" >&5
+$as_echo "no" >&6; }
+
+
+else
+
+			{ $as_echo "$as_me:$LINENO: result: yes" >&5
+$as_echo "yes" >&6; }
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_D_MAKE_ROOT 1
+_ACEOF
+
+
+fi
+
+
+else
+
+		{ $as_echo "$as_me:$LINENO: result: yes" >&5
+$as_echo "yes" >&6; }
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_D_MAKE_ROOT 1
+_ACEOF
+
+
+fi
+
+
+
+
 	{ $as_echo "$as_me:$LINENO: checking whether symbol d_obtain_alias is exported" >&5
 $as_echo_n "checking whether symbol d_obtain_alias is exported... " >&6; }
 	grep -q -E '[[:space:]]d_obtain_alias[[:space:]]' \