Re: [PATCH 5/5] cifs: cancel oplock release callbacks during reconnect

On Tue, Aug 18, 2009 at 1:07 PM, Jeff Layton<[email protected]> wrote:
> cifs_oplock_thread has a check for pTcon->needs_reconnect and will skip
> the CIFSSMBLock call if it's set.
>
> Problem: what if the tcon has this set and then gets reconnected before
> the call goes out on the wire? The oplock release isn't needed and could
> be a bad thing at that point if the filehandle was reclaimed.
>
> Cancel oplock release calls during a reconnect event.
>
> Signed-off-by: Jeff Layton <[email protected]>
> ---
>  fs/cifs/cifsfs.c   |    2 +-
>  fs/cifs/cifsglob.h |    1 +
>  fs/cifs/connect.c  |    9 +++++++++
>  fs/cifs/misc.c     |    1 +
>  4 files changed, 12 insertions(+), 1 deletions(-)
>
> diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
> index 647c5bc..92e06c1 100644
> --- a/fs/cifs/cifsfs.c
> +++ b/fs/cifs/cifsfs.c
> @@ -1024,7 +1024,7 @@ static int cifs_oplock_thread(void *dummyarg)
>                         * to server still is disconnected since oplock
>                         * already released by the server in that case
>                         */
> -                       if (!tcon->need_reconnect) {
> +                       if (!oplock->cancel) {
>                                rc = CIFSSMBLock(0, tcon, oplock->netfid,
>                                                0 /* len */ , 0 /* offset */, 0,
>                                                0, LOCKING_ANDX_OPLOCK_RELEASE,
> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
> index 363dbcf..676c107 100644
> --- a/fs/cifs/cifsglob.h
> +++ b/fs/cifs/cifsglob.h
> @@ -448,6 +448,7 @@ struct oplock_q_entry {
>        struct inode *pinode;
>        struct cifsTconInfo *tcon;
>        __u16 netfid;
> +       bool cancel;
>  };
>
>  /* for pending dnotify requests */
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index f49304d..b7b67e9 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -121,6 +121,7 @@ cifs_reconnect(struct TCP_Server_Info *server)
>        struct cifsSesInfo *ses;
>        struct cifsTconInfo *tcon;
>        struct mid_q_entry *mid_entry;
> +       struct oplock_q_entry *oplock;
>
>        spin_lock(&GlobalMid_Lock);
>        if (server->tcpStatus == CifsExiting) {
> @@ -137,6 +138,7 @@ cifs_reconnect(struct TCP_Server_Info *server)
>
>        /* before reconnecting the tcp session, mark the smb session (uid)
>                and the tid bad so they are not used until reconnected */
> +       spin_lock(&cifs_oplock_lock);
>        read_lock(&cifs_tcp_ses_lock);
>        list_for_each(tmp, &server->smb_ses_list) {
>                ses = list_entry(tmp, struct cifsSesInfo, smb_ses_list);
> @@ -145,9 +147,16 @@ cifs_reconnect(struct TCP_Server_Info *server)
>                list_for_each(tmp2, &ses->tcon_list) {
>                        tcon = list_entry(tmp2, struct cifsTconInfo, tcon_list);
>                        tcon->need_reconnect = true;
> +                       list_for_each_entry(oplock, &cifs_oplock_list, qhead) {
> +                               if (oplock->tcon == tcon)
> +                                       oplock->cancel = true;
> +                       }
>                }
> +
>        }
>        read_unlock(&cifs_tcp_ses_lock);
> +       spin_unlock(&cifs_oplock_lock);
> +
>        /* do not want to be sending data on a socket we are freeing */
>        mutex_lock(&server->srv_mutex);
>        if (server->ssocket) {
> diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
> index 3bf3a52..4a2d297 100644
> --- a/fs/cifs/misc.c
> +++ b/fs/cifs/misc.c
> @@ -612,6 +612,7 @@ is_valid_oplock_break(struct smb_hdr *buf, struct TCP_Server_Info *srv,
>                                oplock->tcon = tcon;
>                                oplock->pinode = inode;
>                                oplock->netfid = netfile->netfid;
> +                               oplock->cancel = false;
>                                spin_lock(&cifs_oplock_lock);
>                                list_add_tail(&oplock->qhead,
>                                              &cifs_oplock_list);
> --
> 1.6.0.6
>
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>


Acked-by: Shirish Pargaonkar <[email protected]>

with a question, does what you say about pTcon->needs_reconnect  apply
to oplock->cancel also?