Messages in this thread |  | | Date | Thu, 11 Jan 2001 15:30:14 +0100 | From | Daniel Phillips <> | Subject | Re: FS callback routines |
| |
Jamie Lokier wrote: > Daniel Phillips wrote: > > [things that can benefit from dnotify] > > locate (reindex only those directories that have changed, keep index > > database current). > > Not a chance. dnotify doesn't work recursively, so you can't monitor > just a few top level directories like "/usr/lib". And have you ever > tried to keep all 3000 directories on your filesystem directories open > at the same time? Would you want to consume that much non-swappable > memory, and also prevent the directories from being removed from the > filesystem? > > Long ago I proposed something similar that works at the disk level, is > recursive, and the checks can be done without keeping directories open. > But I never wrote the code :( That's interesting because it speeds up > make without needing a daemon, and really can speed up > locate/updatedb/find.
It took a little while for the following to dawn on me: it's not hard to make the dnotify scheme work recursively and you don't have to keep 3000 directories open. To modify a file you must have opened all the directories in its path. We need a new event:
DN_OPEN A file in the directory was opened
You open the top level directory and register for events. When somebody opens a subdirectory of the top level directory, you receive notification and register for events on the subdirectory, and so on, down to the file that is actually modified.
-- Daniel - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
|  |