Linux 3.1 compat, fops->fsync()

The Linux 3.1 kernel updated the fops->fsync() callback yet again.
They now pass the requested range and delegate the responsibility
for calling filemap_write_and_wait_range() to the callback.  In
addition imutex is no longer held by the caller and the callback
is responsible for taking the lock if required.

This commit updates the code to provide a zpl_fsync() function
for the updated API.  Implementations for the previous two APIs
are also maintained for compatibility.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #445

config/kernel-fsync.m4

@@ -1,20 +1,63 @@
 dnl #
-dnl # 2.6.35 API change
+dnl # Linux 2.6.x - 2.6.34 API
-dnl # The dentry argument was deamed unused and dropped in 2.6.36.
 dnl #
-AC_DEFUN([ZFS_AC_KERNEL_FSYNC_2ARGS], [
+AC_DEFUN([ZFS_AC_KERNEL_FSYNC_WITH_DENTRY], [
-	AC_MSG_CHECKING([whether fops->fsync() wants 2 args])
 	ZFS_LINUX_TRY_COMPILE([
 		#include <linux/fs.h>
 	],[
-		int (*fsync) (struct file *, int datasync) = NULL;
+		int (*fsync) (struct file *, struct dentry *, int) = NULL;
 		struct file_operations fops __attribute__ ((unused));
 
 		fops.fsync = fsync;
 	],[
-		AC_MSG_RESULT(yes)
+		AC_MSG_RESULT([dentry])
-		AC_DEFINE(HAVE_2ARGS_FSYNC, 1, [fops->fsync() want 2 args])
+		AC_DEFINE(HAVE_FSYNC_WITH_DENTRY, 1,
+			[fops->fsync() with dentry])
 	],[
-		AC_MSG_RESULT(no)
 	])
 ])
+
+dnl #
+dnl # Linux 2.6.35 - Linux 3.0 API
+dnl #
+AC_DEFUN([ZFS_AC_KERNEL_FSYNC_WITHOUT_DENTRY], [
+	ZFS_LINUX_TRY_COMPILE([
+		#include <linux/fs.h>
+	],[
+		int (*fsync) (struct file *, int) = NULL;
+		struct file_operations fops __attribute__ ((unused));
+
+		fops.fsync = fsync;
+	],[
+		AC_MSG_RESULT([no dentry])
+		AC_DEFINE(HAVE_FSYNC_WITHOUT_DENTRY, 1,
+			[fops->fsync() without dentry])
+	],[
+	])
+])
+
+dnl #
+dnl # Linux 3.1 -x 3.x API
+dnl #
+AC_DEFUN([ZFS_AC_KERNEL_FSYNC_RANGE], [
+	ZFS_LINUX_TRY_COMPILE([
+		#include <linux/fs.h>
+	],[
+		int (*fsync) (struct file *, loff_t, loff_t, int) = NULL;
+		struct file_operations fops __attribute__ ((unused));
+
+		fops.fsync = fsync;
+	],[
+		AC_MSG_RESULT([range])
+		AC_DEFINE(HAVE_FSYNC_RANGE, 1,
+			[fops->fsync() with range])
+	],[
+	])
+])
+
+AC_DEFUN([ZFS_AC_KERNEL_FSYNC], [
+	AC_MSG_CHECKING([whether fops->fsync() wants])
+	ZFS_AC_KERNEL_FSYNC_WITH_DENTRY
+	ZFS_AC_KERNEL_FSYNC_WITHOUT_DENTRY
+	ZFS_AC_KERNEL_FSYNC_RANGE
+])

config/kernel.m4

@@ -32,7 +32,7 @@ AC_DEFUN([ZFS_AC_CONFIG_KERNEL], [
 	ZFS_AC_KERNEL_CONST_XATTR_HANDLER
 	ZFS_AC_KERNEL_XATTR_HANDLER_GET
 	ZFS_AC_KERNEL_XATTR_HANDLER_SET
-	ZFS_AC_KERNEL_FSYNC_2ARGS
+	ZFS_AC_KERNEL_FSYNC
 	ZFS_AC_KERNEL_EVICT_INODE
 	ZFS_AC_KERNEL_INSERT_INODE_LOCKED
 	ZFS_AC_KERNEL_D_OBTAIN_ALIAS

configure

@@ -14418,8 +14418,9 @@ fi
 
 
 
-	{ $as_echo "$as_me:$LINENO: checking whether fops->fsync() wants 2 args" >&5
+	{ $as_echo "$as_me:$LINENO: checking whether fops->fsync() wants" >&5
-$as_echo_n "checking whether fops->fsync() wants 2 args... " >&6; }
+$as_echo_n "checking whether fops->fsync() wants... " >&6; }
+
 
 
 cat confdefs.h - <<_ACEOF >conftest.c
@@ -14436,7 +14437,7 @@ int
 main (void)
 {
 
-		int (*fsync) (struct file *, int datasync) = NULL;
+		int (*fsync) (struct file *, struct dentry *, int) = NULL;
 		struct file_operations fops __attribute__ ((unused));
 
 		fops.fsync = fsync;
@@ -14462,11 +14463,11 @@ _ACEOF
   $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
   (exit $ac_status); }; }; then
 
-		{ $as_echo "$as_me:$LINENO: result: yes" >&5
+		{ $as_echo "$as_me:$LINENO: result: dentry" >&5
-$as_echo "yes" >&6; }
+$as_echo "dentry" >&6; }
 
 cat >>confdefs.h <<\_ACEOF
-#define HAVE_2ARGS_FSYNC 1
+#define HAVE_FSYNC_WITH_DENTRY 1
 _ACEOF
 
 
@@ -14474,8 +14475,6 @@ else
   $as_echo "$as_me: failed program was:" >&5
 sed 's/^/| /' conftest.$ac_ext >&5
 
-		{ $as_echo "$as_me:$LINENO: result: no" >&5
-$as_echo "no" >&6; }
 
 
 
@@ -14486,6 +14485,135 @@ fi
 
 
 
+
+
+cat confdefs.h - <<_ACEOF >conftest.c
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+
+		#include <linux/fs.h>
+
+int
+main (void)
+{
+
+		int (*fsync) (struct file *, int) = NULL;
+		struct file_operations fops __attribute__ ((unused));
+
+		fops.fsync = fsync;
+
+  ;
+  return 0;
+}
+
+_ACEOF
+
+
+	rm -Rf build && mkdir -p build
+	echo "obj-m := conftest.o" >build/Makefile
+	if { ac_try='cp conftest.c build && make modules -C $LINUX_OBJ EXTRA_CFLAGS="-Werror-implicit-function-declaration $EXTRA_KCFLAGS" $ARCH_UM M=$PWD/build'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; } >/dev/null && { ac_try='test -s build/conftest.o'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+
+		{ $as_echo "$as_me:$LINENO: result: no dentry" >&5
+$as_echo "no dentry" >&6; }
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_FSYNC_WITHOUT_DENTRY 1
+_ACEOF
+
+
+else
+  $as_echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+
+
+
+fi
+
+	rm -Rf build
+
+
+
+
+
+
+cat confdefs.h - <<_ACEOF >conftest.c
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+
+		#include <linux/fs.h>
+
+int
+main (void)
+{
+
+		int (*fsync) (struct file *, loff_t, loff_t, int) = NULL;
+		struct file_operations fops __attribute__ ((unused));
+
+		fops.fsync = fsync;
+
+  ;
+  return 0;
+}
+
+_ACEOF
+
+
+	rm -Rf build && mkdir -p build
+	echo "obj-m := conftest.o" >build/Makefile
+	if { ac_try='cp conftest.c build && make modules -C $LINUX_OBJ EXTRA_CFLAGS="-Werror-implicit-function-declaration $EXTRA_KCFLAGS" $ARCH_UM M=$PWD/build'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; } >/dev/null && { ac_try='test -s build/conftest.o'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+
+		{ $as_echo "$as_me:$LINENO: result: range" >&5
+$as_echo "range" >&6; }
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_FSYNC_RANGE 1
+_ACEOF
+
+
+else
+  $as_echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+
+
+
+fi
+
+	rm -Rf build
+
+
+
+
+
 	{ $as_echo "$as_me:$LINENO: checking whether sops->evict_inode() exists" >&5
 $as_echo_n "checking whether sops->evict_inode() exists... " >&6; }
 
@@ -19027,8 +19155,9 @@ fi
 
 
 
-	{ $as_echo "$as_me:$LINENO: checking whether fops->fsync() wants 2 args" >&5
+	{ $as_echo "$as_me:$LINENO: checking whether fops->fsync() wants" >&5
-$as_echo_n "checking whether fops->fsync() wants 2 args... " >&6; }
+$as_echo_n "checking whether fops->fsync() wants... " >&6; }
+
 
 
 cat confdefs.h - <<_ACEOF >conftest.c
@@ -19045,7 +19174,7 @@ int
 main (void)
 {
 
-		int (*fsync) (struct file *, int datasync) = NULL;
+		int (*fsync) (struct file *, struct dentry *, int) = NULL;
 		struct file_operations fops __attribute__ ((unused));
 
 		fops.fsync = fsync;
@@ -19071,11 +19200,11 @@ _ACEOF
   $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
   (exit $ac_status); }; }; then
 
-		{ $as_echo "$as_me:$LINENO: result: yes" >&5
+		{ $as_echo "$as_me:$LINENO: result: dentry" >&5
-$as_echo "yes" >&6; }
+$as_echo "dentry" >&6; }
 
 cat >>confdefs.h <<\_ACEOF
-#define HAVE_2ARGS_FSYNC 1
+#define HAVE_FSYNC_WITH_DENTRY 1
 _ACEOF
 
 
@@ -19083,8 +19212,6 @@ else
   $as_echo "$as_me: failed program was:" >&5
 sed 's/^/| /' conftest.$ac_ext >&5
 
-		{ $as_echo "$as_me:$LINENO: result: no" >&5
-$as_echo "no" >&6; }
 
 
 
@@ -19095,6 +19222,135 @@ fi
 
 
 
+
+
+cat confdefs.h - <<_ACEOF >conftest.c
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+
+		#include <linux/fs.h>
+
+int
+main (void)
+{
+
+		int (*fsync) (struct file *, int) = NULL;
+		struct file_operations fops __attribute__ ((unused));
+
+		fops.fsync = fsync;
+
+  ;
+  return 0;
+}
+
+_ACEOF
+
+
+	rm -Rf build && mkdir -p build
+	echo "obj-m := conftest.o" >build/Makefile
+	if { ac_try='cp conftest.c build && make modules -C $LINUX_OBJ EXTRA_CFLAGS="-Werror-implicit-function-declaration $EXTRA_KCFLAGS" $ARCH_UM M=$PWD/build'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; } >/dev/null && { ac_try='test -s build/conftest.o'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+
+		{ $as_echo "$as_me:$LINENO: result: no dentry" >&5
+$as_echo "no dentry" >&6; }
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_FSYNC_WITHOUT_DENTRY 1
+_ACEOF
+
+
+else
+  $as_echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+
+
+
+fi
+
+	rm -Rf build
+
+
+
+
+
+
+cat confdefs.h - <<_ACEOF >conftest.c
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+
+		#include <linux/fs.h>
+
+int
+main (void)
+{
+
+		int (*fsync) (struct file *, loff_t, loff_t, int) = NULL;
+		struct file_operations fops __attribute__ ((unused));
+
+		fops.fsync = fsync;
+
+  ;
+  return 0;
+}
+
+_ACEOF
+
+
+	rm -Rf build && mkdir -p build
+	echo "obj-m := conftest.o" >build/Makefile
+	if { ac_try='cp conftest.c build && make modules -C $LINUX_OBJ EXTRA_CFLAGS="-Werror-implicit-function-declaration $EXTRA_KCFLAGS" $ARCH_UM M=$PWD/build'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; } >/dev/null && { ac_try='test -s build/conftest.o'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+
+		{ $as_echo "$as_me:$LINENO: result: range" >&5
+$as_echo "range" >&6; }
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_FSYNC_RANGE 1
+_ACEOF
+
+
+else
+  $as_echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+
+
+
+fi
+
+	rm -Rf build
+
+
+
+
+
 	{ $as_echo "$as_me:$LINENO: checking whether sops->evict_inode() exists" >&5
 $as_echo_n "checking whether sops->evict_inode() exists... " >&6; }
 

module/zfs/zpl_file.c

@@ -76,27 +76,16 @@ zpl_readdir(struct file *filp, void *dirent, filldir_t filldir)
 	return (error);
 }
 
+#if defined(HAVE_FSYNC_WITH_DENTRY)
 /*
- * 2.6.35 API change,
+ * Linux 2.6.x - 2.6.34 API,
- * As of 2.6.35 the dentry argument to the .fsync() vfs hook was deemed
+ * Through 2.6.34 the nfsd kernel server would pass a NULL 'file struct *'
- * redundant.  The dentry is still accessible via filp->f_path.dentry,
+ * to the fops->fsync() hook.  For this reason, we must be careful not to
- * and we are guaranteed that filp will never be NULL.
+ * use filp unconditionally.
- *
- * 2.6.34 API change,
- * Prior to 2.6.34 the nfsd kernel server would pass a NULL file struct *
- * to the .fsync() hook.  For this reason, we must be careful not to use
- * filp unconditionally in the 3 argument case.
  */
-#ifdef HAVE_2ARGS_FSYNC
-static int
-zpl_fsync(struct file *filp, int datasync)
-{
-	struct dentry *dentry = filp->f_path.dentry;
-#else
 static int
 zpl_fsync(struct file *filp, struct dentry *dentry, int datasync)
 {
-#endif /* HAVE_2ARGS_FSYNC */
 	cred_t *cr = CRED();
 	int error;
 
@@ -108,6 +97,58 @@ zpl_fsync(struct file *filp, struct dentry *dentry, int datasync)
 	return (error);
 }
 
+#elif defined(HAVE_FSYNC_WITHOUT_DENTRY)
+/*
+ * Linux 2.6.35 - 3.0 API,
+ * As of 2.6.35 the dentry argument to the fops->fsync() hook was deemed
+ * redundant.  The dentry is still accessible via filp->f_path.dentry,
+ * and we are guaranteed that filp will never be NULL.
+ */
+static int
+zpl_fsync(struct file *filp, int datasync)
+{
+	struct inode *inode = filp->f_mapping->host;
+	cred_t *cr = CRED();
+	int error;
+
+	crhold(cr);
+	error = -zfs_fsync(inode, datasync, cr);
+	crfree(cr);
+	ASSERT3S(error, <=, 0);
+
+	return (error);
+}
+
+#elif defined(HAVE_FSYNC_RANGE)
+/*
+ * Linux 3.1 - 3.x API,
+ * As of 3.1 the responsibility to call filemap_write_and_wait_range() has
+ * been pushed down in to the .fsync() vfs hook.  Additionally, the i_mutex
+ * lock is no longer held by the caller, for zfs we don't require the lock
+ * to be held so we don't acquire it.
+ */
+static int
+zpl_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
+{
+	struct inode *inode = filp->f_mapping->host;
+	cred_t *cr = CRED();
+	int error;
+
+	error = filemap_write_and_wait_range(inode->i_mapping, start, end);
+	if (error)
+		return (error);
+
+	crhold(cr);
+	error = -zfs_fsync(inode, datasync, cr);
+	crfree(cr);
+	ASSERT3S(error, <=, 0);
+
+	return (error);
+}
+#else
+#error "Unsupported fops->fsync() implementation"
+#endif
+
 ssize_t
 zpl_read_common(struct inode *ip, const char *buf, size_t len, loff_t pos,
      uio_seg_t segment, int flags, cred_t *cr)

zfs_config.h.in

@@ -6,9 +6,6 @@
 /* bio_end_io_t wants 2 args */
 #undef HAVE_2ARGS_BIO_END_IO_T
 
-/* fops->fsync() want 2 args */
-#undef HAVE_2ARGS_FSYNC
-
 /* security_inode_init_security wants 6 args */
 #undef HAVE_6ARGS_SECURITY_INODE_INIT_SECURITY
 
@@ -93,6 +90,15 @@
 /* kernel defines fmode_t */
 #undef HAVE_FMODE_T
 
+/* fops->fsync() with range */
+#undef HAVE_FSYNC_RANGE
+
+/* fops->fsync() without dentry */
+#undef HAVE_FSYNC_WITHOUT_DENTRY
+
+/* fops->fsync() with dentry */
+#undef HAVE_FSYNC_WITH_DENTRY
+
 /* blk_disk_ro() is available */
 #undef HAVE_GET_DISK_RO