On Feb 08, 2008  19:48 +0900, Takashi Sato wrote:

OK I would like to implement the freeze feature on VFS
as the filesystem independent ioctl so that it can be
available on filesystems that have already had write_super_lockfs()
and unlockfs().
The usage for the freeze ioctl is the following.
 int ioctl(int fd, int FIFREEZE, long *timeval);
   fd:file descriptor of mountpoint
   FIFREEZE:request cord for freeze
   timeval:timeout period (second)

And the unfreeze ioctl is the following.
 int ioctl(int fd, int FITHAW, NULL);
   fd:file descriptor of mountpoint
   FITHAW:Request cord for unfreeze

You may as well make the common ioctl the same as the XFS version,
both by number and parameters, so that applications which already
understand the XFS ioctl will work on other filesystems.

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.