fs: Remove old freezing mechanism

Now that all users are converted, we can remove functions, variables, and
constants defined by the old freezing mechanism.

BugLink: https://bugs.launchpad.net/bugs/897421
Tested-by: Kamal Mostafa <kamal@canonical.com>
Tested-by: Peter M. Petrakis <peter.petrakis@canonical.com>
Tested-by: Dann Frazier <dann.frazier@canonical.com>
Tested-by: Massimo Morana <massimo.morana@canonical.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/super.c

@@ -217,7 +217,6 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags)
 		mutex_init(&s->s_dquot.dqio_mutex);
 		mutex_init(&s->s_dquot.dqonoff_mutex);
 		init_rwsem(&s->s_dquot.dqptr_sem);
-		init_waitqueue_head(&s->s_wait_unfrozen);
 		s->s_maxbytes = MAX_NON_LFS;
 		s->s_op = &default_op;
 		s->s_time_gran = 1000000000;

include/linux/fs.h

@@ -1459,7 +1459,6 @@ extern spinlock_t sb_lock;
 enum {
 	SB_UNFROZEN = 0,		/* FS is unfrozen */
 	SB_FREEZE_WRITE	= 1,		/* Writes, dir ops, ioctls frozen */
-	SB_FREEZE_TRANS = 2,
 	SB_FREEZE_PAGEFAULT = 2,	/* Page faults stopped as well */
 	SB_FREEZE_FS = 3,		/* For internal FS use (e.g. to stop
 					 * internal threads if needed) */
@@ -1528,8 +1527,6 @@ struct super_block {
 	struct hlist_node	s_instances;
 	struct quota_info	s_dquot;	/* Diskquota specific options */
 
-	int			s_frozen;
-	wait_queue_head_t	s_wait_unfrozen;
 	struct sb_writers	s_writers;
 
 	char s_id[32];				/* Informational name */
@@ -1585,8 +1582,6 @@ extern struct timespec current_fs_time(struct super_block *sb);
 /*
  * Snapshotting support.
  */
-/* Will go away when all users are converted */
-#define vfs_check_frozen(sb, level) do { } while (0)
 
 void __sb_end_write(struct super_block *sb, int level);
 int __sb_start_write(struct super_block *sb, int level, bool wait);