Re: [Gluster-devel] NULL loc in posix_acl_truncate

[Vijay Bellur]

On 05/27/2012 10:47 AM, Emmanuel Dreyfus wrote:
> Emmanuel Dreyfus<address@hidden>  wrote:
>
> > In frame 10, loc->path and loc->inode are NULL.
>
>
> As I understand this is a FUSE implentation problem. fchmod() produces a
> FUSE SETATTR. If the file is being written, NetBSD FUSE will set mode,
> size, atime, mtime, and fh in this operation. I suspect Linux FUSE only
> sets mode and fh and this is why the bug does not appear on Linux: the
> truncate code path is probably not involved.

For the testcase that you sent out, I see fsi->valid being set to 1 
which indicates only mode on Linux. The truncate path does not get 
involved. I modified the testcase to send ftruncate/truncate and it 
completed successfully.

> Can someone confirm? If this is the case, it suggests the code path may
> have never been tested. I suspect there are bugs there, for instance, in
> pl_truncate_cbk, local is erased after being retreived, which does not
> look right:
>
>          local = frame->local;
>
>          local = mem_get0 (this->local_pool);
I don't see this in pl_truncate_cbk(). mem_get0 is done only in 
pl_truncate(). A code inspection in pl_(f)truncate did not raise any 
suspicions to me.

> About fchmod() setting size: is it a reasonable behavior? FUSE does not
> specify what must happens, so if glusterfs rely on the Linux kernel not
> doing it may be begging for future bugs if that behavior change.

I am not sure why fchmod() should set size. Csaba, any thoughts on this?


Vijay