On Sunday 17 August 2008 05:23:22 pm David Woodhouse wrote: > On Mon, 2008-07-21 at 02:01 +0530, Balaji Rao wrote: > > Here's an implementation of NFS support for btrfs. It does not work in > > one particular case as described in > > http://www.mail-archive.com/linux-btrfs@xxxxxxxxxxxxxxx/msg00298.html. > > I can't get it to work properly. The simple case of exporting and using > a file system works -- but that doesn't exercise the get_parent() or > dentry_to_fh() code paths. To test those, you need to clear the server's > dcache completely -- I prefer just rebooting the server. > OK. I was not very sure if NFS worked across server reboots. > Note that the first problem you'll hit is the lack of stable fsid -- > because btrfs uses an anonymous superblock, it might cause stale file > handles after a reboot, unless your test setup mounts exactly the same > anonymous file systems each time. That bit me when I context switched > from something else and had debugfs mounted before btrfs, then rebooted > and didn't mount debugfs first. I'll deal with the fsid problem > separately; just be aware of it and avoid it for now. > Hmmm.. how do we deal with that ? > The second problem is that btrfs_fh_to_dentry() fails -- it seems we > need to set the key type BTRFS_INODE_ITEM_KEY in btrfs_get_dentry(), > rather than BTRFS_INODE_REF_KEY. I still haven't learned enough to know > precisely what the implications of that are -- but unless I make that > change, btrfs_lookup_inode() fails and btrfs_read_locked_inode() marks > the resulting inode as bad. > Right. Again, my bad. That's a silly mistake, which didn't surface because of bad testing! > You can test that by mounting the exported file system, then rebooting > the server, then running 'ls' in the NFS-mounted file system. > > My next test was to make a deep directory path: mkdir -p a/b/c/d/e/f/g > and then change directory into it. Again reboot the server and run 'ls'. > This time, I see 'ls: cannot open directory .'. In this csse, it seems > to be because btrfs_get_parent() is failing. In my case, it seems to be > because the 'if (slot >= nritems)' check is triggering -- both are set > to 14. I'm now trying to work out precisely what that means... I think this means that the inode ref is not found, which is weird. I remember that it worked with it a really deep path. I'll try to reproduce the problem and see what's going on.. -- Thanks, Balaji -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
