Re: [PATCH 2/2] make pipefs do lazy i_ino assignment and hashing

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Jeff Layton <jlayton@xxxxxxxxxx> wrote:

> This patch updates pipefs to do defer assigning an i_ino value to its inodes
> until someone actually tries to stat it. This allows us to have unique i_ino
> values for the inodes here, without the performance impact for anyone who
> doesn't actually care about it.
> 
> Since we don't have an i_ino value at pipe creation time, we need something
> else to stuff into the dentry name. Here, I'm using the pointer address of
> the inode xor'ed with a random value. There are certainly better hashing
> schemes, so if someone wants to propose a better way to do this, then I'm
> open to looking at it (maybe halfmd4?).

Why XOR? To pretend a non-existent level of security?
Either you can't use the address, or you can read the obfusicator value, too.

OTOH, if sizeof(void*) <= sieof(ino_t), using the address will result in a
unique inode number without need for expensive hashing algorithms.
-- 
Why did the hacker cross the road? To get to the other side.
Why did the cracker cross the road? To get what was on the other side.
The difference is small, but important.
        -- Gandalf Parker
-
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

[Index of Archives]     [Linux Ext4 Filesystem]     [Union Filesystem]     [Filesystem Testing]     [Ceph Users]     [Ecryptfs]     [AutoFS]     [Kernel Newbies]     [Share Photos]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux Cachefs]     [Reiser Filesystem]     [Linux RAID]     [Samba]     [Device Mapper]     [CEPH Development]
  Powered by Linux