On Tue, Apr 17, 2012 at 8:20 AM, Jeff Darcy <jdarcy@xxxxxxxxxx> wrote:
On Tue, 17 Apr 2012 11:14:21 -0400 (EDT)I just did, and if there's anything but the name included I'm missing
Kaleb Keithley <kkeithle@xxxxxxxxxx> wrote:
> ISTR Avati and/or Vijay telling us — when we were in BLR — that the
> hash of the filename is salted with the hash of the pathname up to,
> but not including the filename.
>
> Am I misremembering that? (Of course I haven't looked at the code.)
it. Here's the DHT function that computes the hash.
73 int
74 dht_hash_compute (int type, const char *name, uint32_t *hash_p)
75 {
76 char *rsync_friendly_name = NULL;
77
78 MAKE_RSYNC_FRIENDLY_NAME (rsync_friendly_name, name);
79
80 return dht_hash_compute_internal (type,
rsync_friendly_name, hash_p);
81 }
The name comes from dht_subvol_get_hashed (a few levels up), thus.
380 subvol = dht_layout_search (this, layout, loc->name);
AFAIK loc->name is just the last part of the name, and there's no
provision anywhere in this path for non-textual input like a parent
hash. It would probably be a good idea for us to do something like
that, but currently we don't.
The parent directory's textual path is not part of the hash computation, but it causes a different hash-range map in the inode layout and effectively a different server is picked up for the same basename in different directories.
Avati
