Unable to pwd in ZFS snapshot

[Jaakko Heinonen]

Hi,

On 2010-02-14, Gleb Kurtsou wrote:
> problem here lies in incorrect inode numbers (inconsistency between
> VOP_READDIR and VOP_GETATTR).

It's normal for mount points. This is problem for kernel
vn_fullpath1()/vop_stdvptocnp() because ZFS clears VV_ROOT for snapshot
root vnodes but I don't see this causing a problem in user space.

> Fixing it only in kernel (__getcwd) doesn't necessarily fixes it for
> all cases in userland, getcwd in our libc falls back to comparing
> inode numbers

User space getcwd() works just fine if the .zfs directory is visible (or
am I missing something?). See the code in getcwd.c under comment "If
it's a mount point, have to stat each element because the inode number
in the directory is for the entry in the parent directory, not the inode
number of the mounted file."

User space getcwd() just can't work for hidden directories.

> Fixing inode numbers would also fix pwd issues with namecache disabled.

I don't think so. If the .zfs directory is hidden, vop_stdvptocnp() and
user space getcwd() don't work.

-- 
Jaakko