Hi, On Tue, Mar 14, 2017 at 12:11:40PM +0200, Amir Goldstein wrote: > > - file system indexers / desktop search tools > > - file synchronization tools (like Dropbox, Nextcloud, etc.), > > online backup tools > > This last one is the use case of my employer, Ctera Networks. > Out of curiosity, what is the use case that you are focusing on? I'm working on a file synchronization tool as part of my bachelor thesis at Charles University. When I started (now over a year ago ... long story), there were AFIK no attempts at solving the recursive inotify issue, only a lot of complaints, so I cobbled up together something simple (I'm not a kernel developer by trade, this was my first patch) that would allow me to work on the userspace parts, which are the main bulk. I try to focus on algorithmic and implementation efficiency as opposed to fancy GUIs and similar. I want it to be fast with 100k directories and 10M files in home dir. But it's very WIP so we'll see how that turns out. > I had the feeling that all recursive inotify users are hiding in the shadows, > but was missing more concrete evidence. Yes, even Dropbox uses inotify. They have articles in their help on how to increase inotify.max_user_watches: https://www.dropbox.com/help/145. That's not good PR. ;-) (I'm not affiliated with DB, just pointing that out.) > About the argument of not having to change in-kernel framework, > I don't think it should be a consideration at all. Understood. I tried to stay conservative and non-controversial because I imagined that radical framework changes would take months of discussions (look at the history of statx) and this issue seems to be pressing for quite a lot of people. But rushing is of course not the best strategy either, there are always compromises. > If you don't specify FAN_EVENT_INFO_NAME, you can get filename events > FAN_MOVE|FAN_CREATE|FAN_DELETE without the name. > > What you do get is the file descriptor of the parent. sounds familiar? ;-) I didn't notice this bit. That sounds like a win-win. Filip
