Re: DNOTIFY to INOTIFY migration

[NeilBrown <neilb@suse.de>]

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On Mon, 10 Mar 2014 01:55:15 +0100 David Heidelberger
<david.heidelberger@ixit.cz> wrote:

> Dne 2014-03-10 00:21, NeilBrown napsal:
> > On Fri, 07 Mar 2014 21:30:34 +0100 David Heidelberger
> > <david.heidelberger@ixit.cz> wrote:
> > 
> >> Hello,
> >> 
> >> in linux kernel is DNOTIFY actually marked as deprecated, with 
> >> superior
> >> replacement INOTIFY.
> > 
> > Where is it marked as deprecated?  I would be very surprised if dnotify
> > wasn't supported indefinitely.
> 
> 
> Dnotify is a directory-based per-fd file change notification system
> 	  that uses signals to communicate events to user-space.  There exist
> 	  superior alternatives, but some applications may still rely on
> 	  dnotify.
> 
> (fs/notify/dnotify/Kconfig)

The fact that the new alternatives are (supposedly) superior doesn't mean the
old are deprecated.


> 
> In this moment, for modern systems I'm no aware of software actually 
> using DNOTIFY.

I tend to use DNOTIFY because, much as I hate signals, it actually works with
python while python doesn't know about the new inotify systemcall (though I
know there is now some plug-in thing).
I suspect there is a lot of software that uses DNOTIFY that you don't know
about.


> 
> Actually there is choice between INOTIFY and FSNOTIFY.
> > 
> > (I have no opinion on whether rpc.idmapd should be changed to use 
> > inotify,
> > except based on the "if it ain't broke, don't fix it" principle).
> 
> Well, I'd like to propose build option which notify system include. It 
> seems like *notify support reside only in rpc.idmapd, so it shouldn't be 
> hard.

Feel free to post a patch.  You should make it clear how the change actually
benefits nfs-utils.  Make sure you don't use the word "deprecated" because
dnotify is *not* deprecated.

Thanks,
NeilBrown


> 
> David
> > 
> > NeilBrown
> > 
> >> 
> >> Is any plan to migrate rpc.idmapd to INOTIFY? As I looked, it's just 
> >> one
> >> file.
> >> 
> >> If there is some on-going porting, I'd like to test/report bugs/send
> >> patches, otherwise I'd like to try port it.
> >> 
> >> Thank you for answer
> >> David Heidelberger (okias)
> >> --
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> >> in
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