UBIFS: nuke pdflush from comments

The pdflush thread is long gone, so this patch removes references to pdflush
from UBIFS comments.
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/ubifs/file.c

@@ -37,11 +37,11 @@
  *
  * A thing to keep in mind: inode @i_mutex is locked in most VFS operations we
  * implement. However, this is not true for 'ubifs_writepage()', which may be
- * called with @i_mutex unlocked. For example, when pdflush is doing background
- * write-back, it calls 'ubifs_writepage()' with unlocked @i_mutex. At "normal"
- * work-paths the @i_mutex is locked in 'ubifs_writepage()', e.g. in the
- * "sys_write -> alloc_pages -> direct reclaim path". So, in 'ubifs_writepage()'
- * we are only guaranteed that the page is locked.
+ * called with @i_mutex unlocked. For example, when flusher thread is doing
+ * background write-back, it calls 'ubifs_writepage()' with unlocked @i_mutex.
+ * At "normal" work-paths the @i_mutex is locked in 'ubifs_writepage()', e.g.
+ * in the "sys_write -> alloc_pages -> direct reclaim path". So, in
+ * 'ubifs_writepage()' we are only guaranteed that the page is locked.
  *
  * Similarly, @i_mutex is not always locked in 'ubifs_readpage()', e.g., the
  * read-ahead path does not lock it ("sys_read -> generic_file_aio_read ->

fs/ubifs/super.c

@@ -303,7 +303,7 @@ static int ubifs_write_inode(struct inode *inode, struct writeback_control *wbc)
 	mutex_lock(&ui->ui_mutex);
 	/*
 	 * Due to races between write-back forced by budgeting
-	 * (see 'sync_some_inodes()') and pdflush write-back, the inode may
+	 * (see 'sync_some_inodes()') and background write-back, the inode may
 	 * have already been synchronized, do not do this again. This might
 	 * also happen if it was synchronized in an VFS operation, e.g.
 	 * 'ubifs_link()'.