Messages in this thread | | | From | (Eric W. Biederman) | Date | Fri, 17 Aug 2012 13:58:31 -0700 | Subject | Re: [patch 4/8] fs, exportfs: Add export_encode_inode_fh helper |
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Al Viro <viro@ZenIV.linux.org.uk> writes:
> On Thu, Aug 16, 2012 at 06:15:53PM +0400, Cyrill Gorcunov wrote: >> On Thu, Aug 16, 2012 at 02:03:00PM +0000, James Bottomley wrote: >> > > > 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? >> >> Well, after looking into do_sys_name_to_handle->exportfs_encode_fh >> sequence more precisely it seems it will be easier to extend >> exportfs_encode_fh to support inodes directly instead of playing >> with notify code (again, if i'm not missing something too). >> i'm cooking a patch to show (once it's tested i'll send it out). > > Good luck doing that with e.g. VFAT... And then there's such thing > as filesystems that don't have ->encode_fh() for a lot of very good > reasons; just try to do that on sysfs, for example. Or on ramfs, > for that matter... And while saying "you can't export that over > NFS" seems to work fine, idiotify-lovers will screech if you try > to ban their perversion of choice on those filesystems.
For whatever it is worth inotify does not currently work on sysfs or procfs or any other filesystem that looks like a network filesystem and whose modifications don't proceed through the vfs like a normal filesystem.
Eric
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