reiserfs: convert j_flush_sem to mutex

j_flush_sem is a semaphore but uses it as if it were a mutex.  This patch
converts it to a mutex.

[akpm@linux-foundation.org: fix mutex_trylock retval treatment]
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Edward Shishkin <edward.shishkin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/reiserfs_fs_sb.h b/include/linux/reiserfs_fs_sb.h
index 49b639b..c075172 100644
--- a/include/linux/reiserfs_fs_sb.h
+++ b/include/linux/reiserfs_fs_sb.h
@@ -194,7 +194,7 @@
 
 	time_t j_trans_start_time;	/* time this transaction started */
 	struct mutex j_mutex;
-	struct semaphore j_flush_sem;
+	struct mutex j_flush_mutex;
 	wait_queue_head_t j_join_wait;	/* wait for current transaction to finish before starting new one */
 	atomic_t j_jlock;	/* lock for j_join_wait */
 	int j_list_bitmap_index;	/* number of next list bitmap to use */