I changed the comment to
+ /*
+ * See commit 2f94a3125b87. Increment the refcount when we
+ * get a lease for root, release it if lease break occurs
+ */
and added Aurelien's Reviewed-by. Let me know if you see any
additional problems.
On Sat, Apr 17, 2021 at 5:54 AM Aurélien Aptel <aaptel@xxxxxxxx> wrote:
>
> Hi,
>
> This is better I think.
>
> Muhammad Usama Anjum <musamaanjum@xxxxxxxxx> writes:
> > @@ -894,6 +891,10 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
> >
> > /* BB TBD check to see if oplock level check can be removed below */
> > if (o_rsp->OplockLevel == SMB2_OPLOCK_LEVEL_LEASE) {
> > + /*
> > + * caller expects this func to set the fid in crfid to valid
> > + * cached root, so increment the refcount.
> > + */
>
> This comment is misleading. crfid variable doesn't exist anymore, and
> the kref_get() here is because of this commit:
>
> commit 2f94a3125b87
> Author: Ronnie Sahlberg <lsahlber@xxxxxxxxxx>
> Date: Thu Mar 28 11:20:02 2019 +1000
>
> cifs: fix kref underflow in close_shroot()
>
> [...]
> --> This extra get() is only used to hold the structure until we get a lease
> --> break from the server at which point we will kref_put() it during lease
> --> processing.
> [...]
>
>
>
> When we queue a lease break, we usually get() the cifsFileInfo, but if
> that cifsFileInfo is backed by a cached_fid, the cached_fid isn't
> bumped. That commit was probably a work around for that.
>
> @Ronnie :
>
> struct cached_fid is starting to look very much like struct
> cifsFileInfo. I wonder why we couldn't use it, along with
> find_writable_file()/find_readable_file() to handle the caching.
>
> Alternatively, make cifsFileInfo use cached_fid (perhaps renaming it in
> the process, I don't know)
>
> Because I suspect a lot more issues will come up regarding cached_fid
> refcount and cifsFileInfo refcount going out of sync otherwise.
>
> Cheers,
> --
> Aurélien Aptel / SUSE Labs Samba Team
> GPG: 1839 CB5F 9F5B FB9B AA97 8C99 03C8 A49B 521B D5D3
> SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg, DE
> GF: Felix Imendörffer, Mary Higgins, Sri Rasiah HRB 247165 (AG München)
>
--
Thanks,
Steve
