Notify intent to modify a buffer for metadata (not data) update.
int journal_get_write_access(handle_t * handle, struct buffer_head * bh);
handle
transaction to add buffer modifications to
bh
bh to be used for metadata writes
Returns an error code or 0 on success.
In full data journalling mode the buffer may be of type BJ_AsyncData, because we're writeing a buffer which is also part of a shared mapping.