On 08/16/2012 06:03 PM, James Bottomley wrote: > On Thu, 2012-08-16 at 17:54 +0400, Cyrill Gorcunov wrote: >> On Thu, Aug 16, 2012 at 02:50:19PM +0100, Al Viro wrote: >>> On Thu, Aug 16, 2012 at 05:47:06PM +0400, Pavel Emelyanov wrote: >>>> On 08/16/2012 05:43 PM, Al Viro wrote: >>>>> On Thu, Aug 16, 2012 at 04:38:14PM +0400, Cyrill Gorcunov wrote: >>>>> >>>>>> Hi Bruce, thinking a bit more I guess using general encode_fh is not that >>>>>> convenient since it operates with dentries while our fdinfo output deals >>>>>> with inodes. Thus I should either provide some new encode_fh variant >>>>>> which would deal with inodes directly without "parents". Which doesn't >>>>>> look for me anyhow better than the new export_encode_inode_fh helper. >>>>> >>>>> Huh? You do have dentries, for crying out loud... >>>> >>>> Sometimes we don't -- the inotify thing gets an inode only. >>>> Unlike other notifies that have dentries at hands... >>> >>> What's wrong with saying "we don't support idiotify"? >> >> Al, we need some way to restore inotifies after checkpoint. >> At the very early versions of these patches I simply added >> dentry to the inotify mark thus once inotify created we always >> have a dentry to refer on in encode_fh, but I'm not sure if >> this will be good design. > > Actually, I was about to suggest this. This can be done internally > within fs/notify without actually modifying the syscall interface, can't > it, since they take a path which is used to obtain the inode? It looks > like the whole of the inotify interface could be internally recast to > use dentries instead of inodes. Unless I've missed something obvious? This will change the observable by userspace behavior. Various apps inotify a file, then rename/unlink/link it or do tricks with mounts container the file. And it works one way if the dentry+mount reference is 0 (now) and some other way if it's not (after the proposed change). The dentries-related behavior is especially bad on NFS with its silly-renames decisions based on dentry reference counters. The mount-related one is bad in general. I'm saying this, because we were facing such problems at approx. once-a-week rate when we did this in OpenVZ :( > James > Thanks, Pavel -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
