> -----Original Message----- > From: Al Viro [mailto:viro@xxxxxxxxxxxxxxxxxx] > Sent: Thursday, December 15, 2011 4:33 PM > To: Maxim Uvarov > Cc: linux-nfs@xxxxxxxxxxxxxxx; bfields@xxxxxxxxxxxx; Myklebust, Trond; > john@xxxxxxxxxxxxxxxxx; rlove@xxxxxxxxx; eparis@xxxxxxxxxxxxxx > Subject: Re: [PATCH] NFS/INOTIFY: inotify user when deleting files on nfs > > On Thu, Dec 15, 2011 at 11:12:30AM -0800, Maxim Uvarov wrote: > > > 1. Original VFS code already has "if NFS", in vfs_unlink(). Because of > > code does not call d_delete() it has to call notification from > > d_delete(). > > > > 2. inotify is done on VFS layer. So logically it has to work on all > > file systems. > > You are using a very odd meaning of the word "logically", then. Note that > inotify does *not* work on NFS, no matter what vfs_unlink() would do. > Simply because files are removed on server, not in VFS. And server does not > notify clients of such removals. Ergo, any software that relies on inotify > delivering notifications of files being removed is broken on NFS. > That has nothing whatsoever to the layer in kernel where it's handled; the > information asked for is simply not available to client. Period. > > Incidentally, inotify does not work on a bunch of local filesystems, starting > with procfs. And won't work, unless you are seriously proposing to generate > events on things like open()/dup2()/etc. In this case we might very well have > objects appearing and disappearing without ever having had a dentry. The other thing to note is that even if there were value in having only client support for the locally performed operations, the way NFS deletes work is fundamentally different to the way that POSIX unlink works: if the file is still open, it isn't deleted, it is just renamed. In consequence, it not only still appears in readdir() requests (albeit under a different name), but it acts in all ways shapes and forms as the same regular file but with the curious property that when the last user closes it gets deleted. IOW: the assumption that we would need to generate an fsnotify_nameremove event here is in any case flawed. It would rather be fsnotify_move, which I suspect would still trip up these LTP tests... Cheers Trond -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
