LWN: Comments on "Watching filesystem events with inotify"

Tutorial with code examples

dmarti — 2006-01-23T19:50:31+00:00

Robert Love's tutorial Intro to inotify has good code examples (using a 2.6.13 kernel).

Watching filesystem events with inotify

Drevic — 2005-11-18T13:03:04+00:00

INOTIFY on SUSE 10.0 Linux

Starting from kernel 2.6.13, inotify is part of the kernel.
/dev/inotify IS NOT AVAILABLE anymore - instead of it, there are system calls

inotify_init
inotify_add_watch
inotify_rm_watch

Please see my web page to find out more details:
http://www.drevic.wz.cz/index.html

Watching filesystem events with inotify

gravious — 2005-08-29T09:14:33+00:00

erm, check out rlocate :)
i use it on gentoo, and it just works (tm)

Watching filesystem events with inotify

stevef — 2005-06-21T18:02:22+00:00

file/directory change notification would be particularly useful on network files (remote files accessed through network filesystems such as nfs or cifs, or cluster filesystems). The current D_NOTIFY fcntl can be intercepted by a filesystem.

Can filesystems intercept inotify?

why not a syscall

fursten — 2004-12-02T14:43:03+00:00

My first reaction was "Why not add pioctl and use that?". For those who don't know pioctl: it's a syscall used by AFS and a couple of other remote fs implmementations. It's essentially ioctl on paths instead of file descriptors. This means that you get rid of the dnotify problems with the need of having the watched file open.

I have on the other hand not studied this in any depth...

Another pseudodevice

nobrowser — 2004-10-07T23:36:56+00:00

Why? Why not netlink?

why not a syscall

huaz — 2004-10-07T20:10:10+00:00

Seems a syscall is more appropriate than a special device interface.

Watching filesystem events with inotify

miallen — 2004-10-02T09:34:08+00:00

Here, here. Slocate is an abomination. Something about my laptop that causes the system to really freeze up. I turned it off long ago in favor of running it manually once in a while. It's really amazing such a crude technique has lasted this long. It will be a glorious day when slocate is replaced with something that has proper fs/kernel support.

Watching filesystem events with inotify

joeshaw — 2004-10-01T19:34:55+00:00

You might be interested in beagle, which aims to index users' data and integrate it with the desktop. You can follow a lot of the development in the blogs at Planet Beagle.

Watching filesystem events with inotify

elanthis — 2004-09-30T20:10:43+00:00

ioctls are still frowned upon, yes. they just happen to have their uses.

Watching filesystem events with inotify

bronson — 2004-09-30T17:50:08+00:00

Is there any chance of getting the locate command to use inotify? Incremental indexing would be sooo nice compared to brinnging my system to its knees at 2:00 every morning.

Does anybody remember ON:Location? That was a pretty amazing piece of software... Of course, writing something like that nowadays would be quite a bit more involved than just patching out a few HFS hooks.

Typo

corbet — 2004-09-30T14:22:51+00:00

Fixed, thanks.

Request: typo reports sent to lwn@lwn.net have a higher chance of being seen and acted upon quickly...

Typo

nhasan — 2004-09-30T14:20:50+00:00

IN_CREATE_FILE and IN_DELETE_FILE (creation and creation of files within a directory), IN_DELETE_FILE (when a monitored file is deleted),

Can you spot the problem?

Watching filesystem events with inotify

rjw — 2004-09-30T14:18:02+00:00

I wasn't really asking about this specific case.
I was just wondering if this principle was still current...
it seems like new ioctl() calls are coming thick and fast.

Watching filesystem events with inotify

elanthis — 2004-09-30T13:27:43+00:00

The ioctl is simply easier to code and use, so it was used.

The inotify developer is quite willing to switch to a write() based interface, if Linus/Andrew decide it's necessary.

Watching filesystem events with inotify

rjw — 2004-09-30T09:36:51+00:00

I remember long ago reading ( I believe on these very pages) that ioctl() was considered a bit skanky, and really people should be making devices that just need read() & write().

And if one of them has another meaning already, a separate control device should be created.

That way echo & friends can be used to test/use all this functionality...

What happened to this idea?

No more timer

xav — 2004-09-30T08:54:49+00:00

Well, the only remaining bad design I saw (perhaps there are others) in inotify was the use of a fixed timer to dispatch events to listening tasks. RML has fixed that this week. Apparently some are still complaining about some quirks here and there, but that means they'll be ironed out soon.