gfs2: Fix missed wakeups in find_insert_glock

Mark Syms has reported seeing tasks that are stuck waiting in
find_insert_glock. It turns out that struct lm_lockname contains four padding
bytes on 64-bit architectures that function glock_waitqueue doesn't skip when
hashing the glock name. As a result, we can end up waking up the wrong
waitqueue, and the waiting tasks may be stuck forever.

Fix that by using ht_parms.key_len instead of sizeof(struct lm_lockname) for
the key length.

Reported-by: Mark Syms <[e-mail]>
Signed-off-by: Andreas Gruenbacher <[e-mail]>
Signed-off-by: Bob Peterson <[e-mail]>

fs/gfs2/glock.c

···
 
 static wait_queue_head_t *glock_waitqueue(struct lm_lockname *name)
 {
-	u32 hash = jhash2((u32 *)name, sizeof(*name) / 4, 0);
+	u32 hash = jhash2((u32 *)name, ht_parms.key_len / 4, 0);
 
 	return glock_wait_table + hash_32(hash, GLOCK_WAIT_TABLE_BITS);
 }