Hello, I want to block IO coming from filesystem while mapping bh. If the MD is read and written as a file (like dd if=/dev/zero of=/dev/mapper/vd0 ..), we can override the ops->read() and ops->write() of the MD (/dev/mapper/vd0), and block the reading and writing properly. But if we make a filesystem on the MD and read/write through the filesystem I do not know how to achieve this. There is a function named __lock_fs() in dm.c in kernel-2.6.6, which calls the function of freeze_bdev() in buffer.c. I have two questions about these functions: 1. If __lock_fs() can block all current reading and writing coming from the filesystem based on the MD which we controlled? 2. If there is any similar function can be called by MD in kernel-2.4.*? How can we block all current reading and writing coming from the filesystem based on the MD? As I know, dm_suspend() in dm.c can defer the IO, but can not block it. Thanks! Ji Haitao
