must decrement inode->i_readcount directly
must decrement inode->i_readcount directly

- we used to use i_readcount_dec if it was available to do this
  however, i_readcount_dec checks the value for zero and we are
  decrementing it just before returning to the dentry_open()
  caller that will, incorrectly, increment it.  This avoids the
  BUGON() while performing the same action.

openss7/openss7,openss7/openss7,openss7/openss7,openss7/openss7,openss7/openss7,openss7/openss7,openss7/openss7,openss7/openss7