Re: f2fs crypto: add symlink encryption

[Jaegeuk Kim <jaegeuk@kernel.org>]

On Tue, May 12, 2015 at 09:36:21PM +0300, Dan Carpenter wrote:
> On Tue, May 12, 2015 at 11:17:16AM -0700, Jaegeuk Kim wrote:
> > > For example, shouldn't we release f2fs_lock_op(sbi) when f2fs_add_link()
> > > fails earlier?
> > 
> > The pair of f2fs_lock_op and f2fs_unlock_op here is used to keep FS
> > consistency.
> > And, the handle_failed_inode() should be covered by f2fs_lock_op, so there is
> > no reason to do unlock and lock redundantly to handle the error case.
> 
> Yes, you are right, but the code is still not correct unfortunately.

Yeah, it was. Please check the V2 patch.

Thanks,

> 
> fs/f2fs/namei.c
>    424  
>    425          f2fs_lock_op(sbi);
>    426          err = f2fs_add_link(dentry, inode);
>    427          if (err)
>    428                  goto out;
>                         ^^^^^^^^
> Holding the lock.  This is correct as you say.
> 
>    429          f2fs_unlock_op(sbi);
>    430  
>    431          if (f2fs_encrypted_inode(dir)) {
>    432                  struct qstr istr = QSTR_INIT(symname, len);
>    433  
>    434                  err = f2fs_inherit_context(dir, inode, NULL);
>    435                  if (err)
>    436                          goto out;
>                                 ^^^^^^^^
> Not holding the lock.  This is a double unlock bug.
> 
>    437  
>    438                  err = f2fs_setup_fname_crypto(inode);
>    439                  if (err)
>    440                          goto out;
> 
> regards,
> dan carpenter

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