Hi, Ted wrote:
And I do agree that we probably should just implement this in filesystem independent way, in which case all of the filesystems that support this already have super_operations functions write_super_lockfs() and unlockfs(). So if this is done using a new system call, there should be no filesystem-specific changes needed, and all filesystems which support those super_operations method functions would be able to provide this functionality to the new system call.
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 I think we need the timeout feature which thaws the filesystem after lapse of specified time for a fail-safe in case the freezer accesses the frozen filesystem and causes a deadlock. I intend to implement the timeout feature on VFS. (This is realized by registering the delayed work which calls thaw_bdev() to the delayed work queue.) Any comments are very welcome. Cheers, Takashi - To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
