Messages in this thread | ![/](/images/icornerl.gif) | | Subject | Re: [patch] stop inotify from sending random DELETE_SELF event under load | From | John McCutchan <> | Date | Mon, 19 Sep 2005 23:51:44 -0400 |
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On Tue, 2005-09-20 at 04:31 +0100, Al Viro wrote: > On Mon, Sep 19, 2005 at 06:37:43PM -0700, Linus Torvalds wrote: > > > > > > On Mon, 19 Sep 2005, John McCutchan wrote: > > > > > > Below is a patch that fixes the random DELETE_SELF events when the > > > system is under load. The problem is that the DELETE_SELF event is sent > > > from dentry_iput, which is called in two code paths, > > > > > > 1) When a dentry is being deleted > > > 2) When the dcache is being pruned. > > > > No no. > > > > The problem is that you put the "fsnotify_inoderemove(inode);" in the > > wrong place, and I and Al never noticed. > > > > iput() doesn't have anything to do with delete at all, and adding a flag > > to it would be wrong. The inode may stay around _after_ the unlink() for > > as long as it has users (or much longer, if you have hardlinks ;). > > > > You should probably move the "fsnotify_inoderemove(inode);" call into > > generic_delete_inode() instead, just after "security_inode_delete()". No > > new flags, just a new place. > > > > (Oh, I think you need to add it to "hugetlbfs_delete_inode()" too). > > > > There's still a potential problem there: some network filesystems seem to > > use "generic_delete_inode()" as their "drop_inode" thing. Which may mean > > that you get spurious delete messages when the reference is dropped. I > > don't see how to avoid that, though - we fundamentally don't _know_ when > > the inode actually gets deleted. > > > > Al, do you have any comments? Anything stupid I missed? > > One fundamentally stupid thing is exposing to userland events that > are none of its fscking business. Link removal - sure. Last link > removal - perhaps, but that's not obvious; in any case it should be > tied to notification of link removal. But inode getting freed or > last dentry going away is none of the userland concern.
I just thought I should clarify exactly when we want to send the DELETE_SELF event to user space:
A path which points to inode X has been deleted.
-- John McCutchan <ttb@tentacle.dhs.org> - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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