Thanks, Jan, it's much clearer now what I need to do. > So most notably they want the ioctl to work not only for block devices but also for any regular file. That's easily doable - you just call > filemap_write_and_wait() and invalidate_inode_pages2() in the ioctl handler for regular files. All right, so I need to find out how I can direct the new ioctl to file-systems as well. I thought that I could get away with it by simply looking at which file-systems have the same block device as the one to which the ioctl is directed, but IIUC this doesn't make sense as NFS doesn't use a block device at all. > Also they wanted to be able to specify a range of a mapping to invalidate - > that's easily doable as well. Finally they wanted a 'flags' argument so you can > additionally ask fs to invalidate also some metadata. How invalidation is done > will be a fs specific thing and for now I guess we don't need to go into > details. NFS guys can sort that out when they decide to implement it. So after I've figured out how to direct this new ioctl to a file-system, I need to understand out how to invalidate a specific range of data. I will gracefully fail metadata invalidation operations with EOPNOTSUPP or ENOSYS. > So in the beginning we can just have u64 flags argument and in it a single > 'INVAL_DATA' flag meaning that invalidation of data in a given range is > requested. Later NFS guys can add further flags. OK that I can do. I suppose we'll always fail metadata invalidation operations when the target of the ioctl is a block device. Thanks -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
