reviewed-by me
On Thu, 30 Mar 2023 at 06:20, Paulo Alcantara <pc@xxxxxxxxxxxxx> wrote:
>
> Prevent multiple threads of doing negotiate, session setup and tree
> connect by holding @ses->session_mutex in cifs_reconnect_tcon() while
> reconnecting session and tcon.
>
> Signed-off-by: Paulo Alcantara (SUSE) <pc@xxxxxxxxxxxxx>
> ---
> fs/cifs/cifssmb.c | 21 +++++++++++++++------
> 1 file changed, 15 insertions(+), 6 deletions(-)
>
> diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
> index 38a697eca305..c9d57ba84be4 100644
> --- a/fs/cifs/cifssmb.c
> +++ b/fs/cifs/cifssmb.c
> @@ -71,7 +71,7 @@ cifs_reconnect_tcon(struct cifs_tcon *tcon, int smb_command)
> int rc;
> struct cifs_ses *ses;
> struct TCP_Server_Info *server;
> - struct nls_table *nls_codepage;
> + struct nls_table *nls_codepage = NULL;
>
> /*
> * SMBs NegProt, SessSetup, uLogoff do not have tcon yet so check for
> @@ -99,6 +99,7 @@ cifs_reconnect_tcon(struct cifs_tcon *tcon, int smb_command)
> }
> spin_unlock(&tcon->tc_lock);
>
> +again:
> rc = cifs_wait_for_server_reconnect(server, tcon->retry);
> if (rc)
> return rc;
> @@ -110,8 +111,7 @@ cifs_reconnect_tcon(struct cifs_tcon *tcon, int smb_command)
> }
> spin_unlock(&ses->chan_lock);
>
> - nls_codepage = load_nls_default();
> -
> + mutex_lock(&ses->session_mutex);
> /*
> * Recheck after acquire mutex. If another thread is negotiating
> * and the server never sends an answer the socket will be closed
> @@ -120,29 +120,38 @@ cifs_reconnect_tcon(struct cifs_tcon *tcon, int smb_command)
> spin_lock(&server->srv_lock);
> if (server->tcpStatus == CifsNeedReconnect) {
> spin_unlock(&server->srv_lock);
> + mutex_lock(&ses->session_mutex);
> +
> + if (tcon->retry)
> + goto again;
> rc = -EHOSTDOWN;
> goto out;
> }
> spin_unlock(&server->srv_lock);
>
> + nls_codepage = load_nls_default();
> +
> /*
> * need to prevent multiple threads trying to simultaneously
> * reconnect the same SMB session
> */
> + spin_lock(&ses->ses_lock);
> spin_lock(&ses->chan_lock);
> - if (!cifs_chan_needs_reconnect(ses, server)) {
> + if (!cifs_chan_needs_reconnect(ses, server) &&
> + ses->ses_status == SES_GOOD) {
> spin_unlock(&ses->chan_lock);
> + spin_unlock(&ses->ses_lock);
>
> /* this means that we only need to tree connect */
> if (tcon->need_reconnect)
> goto skip_sess_setup;
>
> - rc = -EHOSTDOWN;
> + mutex_unlock(&ses->session_mutex);
> goto out;
> }
> spin_unlock(&ses->chan_lock);
> + spin_unlock(&ses->ses_lock);
>
> - mutex_lock(&ses->session_mutex);
> rc = cifs_negotiate_protocol(0, ses, server);
> if (!rc)
> rc = cifs_setup_session(0, ses, server, nls_codepage);
> --
> 2.40.0
>
