Revert "writeback: fix WB_SYNC_NONE writeback from umount"

This reverts commit e913fc825dc685a444cb4c1d0f9d32f372f59861.

We are investigating a hang associated with the WB_SYNC_NONE changes,
so revert them for now.

Conflicts:

	fs/fs-writeback.c
	mm/page-writeback.c

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index e6e0cb5..aee5f6c 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -106,7 +106,7 @@
 void bdi_unregister(struct backing_dev_info *bdi);
 int bdi_setup_and_register(struct backing_dev_info *, char *, unsigned int);
 void bdi_start_writeback(struct backing_dev_info *bdi, struct super_block *sb,
-				long nr_pages, int sb_locked);
+				long nr_pages);
 int bdi_writeback_task(struct bdi_writeback *wb);
 int bdi_has_dirty_io(struct backing_dev_info *bdi);
 void bdi_arm_supers_timer(void);
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index cc97d6c..f6413465 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -65,15 +65,6 @@
 	 * so we use a single control to update them
 	 */
 	unsigned no_nrwrite_index_update:1;
-
-	/*
-	 * For WB_SYNC_ALL, the sb must always be pinned. For WB_SYNC_NONE,
-	 * the writeback code will pin the sb for the caller. However,
-	 * for eg umount, the caller does WB_SYNC_NONE but already has
-	 * the sb pinned. If the below is set, caller already has the
-	 * sb pinned.
-	 */
-	unsigned sb_pinned:1;
 };
 
 /*
@@ -82,7 +73,6 @@
 struct bdi_writeback;
 int inode_wait(void *);
 void writeback_inodes_sb(struct super_block *);
-void writeback_inodes_sb_locked(struct super_block *);
 int writeback_inodes_sb_if_idle(struct super_block *);
 void sync_inodes_sb(struct super_block *);
 void writeback_inodes_wbc(struct writeback_control *wbc);