This is a note to let you know that I've just added the patch titled CIFS: Reconnect expired SMB sessions to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: cifs-reconnect-expired-smb-sessions.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 511c54a2f69195b28afb9dd119f03787b1625bb4 Mon Sep 17 00:00:00 2001 From: Pavel Shilovsky <pshilov@xxxxxxxxxxxxx> Date: Sat, 8 Jul 2017 14:32:00 -0700 Subject: CIFS: Reconnect expired SMB sessions From: Pavel Shilovsky <pshilov@xxxxxxxxxxxxx> commit 511c54a2f69195b28afb9dd119f03787b1625bb4 upstream. According to the MS-SMB2 spec (3.2.5.1.6) once the client receives STATUS_NETWORK_SESSION_EXPIRED error code from a server it should reconnect the current SMB session. Currently the client doesn't do that. This can result in subsequent client requests failing by the server. The patch adds an additional logic to the demultiplex thread to identify expired sessions and reconnect them. Signed-off-by: Pavel Shilovsky <pshilov@xxxxxxxxxxxxx> Signed-off-by: Steve French <smfrench@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/cifs/cifsglob.h | 2 ++ fs/cifs/cifssmb.c | 7 +++++++ fs/cifs/connect.c | 7 +++++++ fs/cifs/smb2ops.c | 16 ++++++++++++++++ 4 files changed, 32 insertions(+) --- a/fs/cifs/cifsglob.h +++ b/fs/cifs/cifsglob.h @@ -365,6 +365,8 @@ struct smb_version_operations { unsigned int (*calc_smb_size)(void *); /* check for STATUS_PENDING and process it in a positive case */ bool (*is_status_pending)(char *, struct TCP_Server_Info *, int); + /* check for STATUS_NETWORK_SESSION_EXPIRED */ + bool (*is_session_expired)(char *); /* send oplock break response */ int (*oplock_response)(struct cifs_tcon *, struct cifs_fid *, struct cifsInodeInfo *); --- a/fs/cifs/cifssmb.c +++ b/fs/cifs/cifssmb.c @@ -1457,6 +1457,13 @@ cifs_readv_receive(struct TCP_Server_Inf return length; server->total_read += length; + if (server->ops->is_session_expired && + server->ops->is_session_expired(buf)) { + cifs_reconnect(server); + wake_up(&server->response_q); + return -1; + } + if (server->ops->is_status_pending && server->ops->is_status_pending(buf, server, 0)) { discard_remaining_data(server); --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -796,6 +796,13 @@ standard_receive3(struct TCP_Server_Info cifs_dump_mem("Bad SMB: ", buf, min_t(unsigned int, server->total_read, 48)); + if (server->ops->is_session_expired && + server->ops->is_session_expired(buf)) { + cifs_reconnect(server); + wake_up(&server->response_q); + return -1; + } + if (server->ops->is_status_pending && server->ops->is_status_pending(buf, server, length)) return -1; --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -1018,6 +1018,18 @@ smb2_is_status_pending(char *buf, struct return true; } +static bool +smb2_is_session_expired(char *buf) +{ + struct smb2_hdr *hdr = (struct smb2_hdr *)buf; + + if (hdr->Status != STATUS_NETWORK_SESSION_EXPIRED) + return false; + + cifs_dbg(FYI, "Session expired\n"); + return true; +} + static int smb2_oplock_response(struct cifs_tcon *tcon, struct cifs_fid *fid, struct cifsInodeInfo *cinode) @@ -1609,6 +1621,7 @@ struct smb_version_operations smb20_oper .close_dir = smb2_close_dir, .calc_smb_size = smb2_calc_size, .is_status_pending = smb2_is_status_pending, + .is_session_expired = smb2_is_session_expired, .oplock_response = smb2_oplock_response, .queryfs = smb2_queryfs, .mand_lock = smb2_mand_lock, @@ -1690,6 +1703,7 @@ struct smb_version_operations smb21_oper .close_dir = smb2_close_dir, .calc_smb_size = smb2_calc_size, .is_status_pending = smb2_is_status_pending, + .is_session_expired = smb2_is_session_expired, .oplock_response = smb2_oplock_response, .queryfs = smb2_queryfs, .mand_lock = smb2_mand_lock, @@ -1773,6 +1787,7 @@ struct smb_version_operations smb30_oper .close_dir = smb2_close_dir, .calc_smb_size = smb2_calc_size, .is_status_pending = smb2_is_status_pending, + .is_session_expired = smb2_is_session_expired, .oplock_response = smb2_oplock_response, .queryfs = smb2_queryfs, .mand_lock = smb2_mand_lock, @@ -1862,6 +1877,7 @@ struct smb_version_operations smb311_ope .close_dir = smb2_close_dir, .calc_smb_size = smb2_calc_size, .is_status_pending = smb2_is_status_pending, + .is_session_expired = smb2_is_session_expired, .oplock_response = smb2_oplock_response, .queryfs = smb2_queryfs, .mand_lock = smb2_mand_lock, Patches currently in stable-queue which might be from pshilov@xxxxxxxxxxxxx are queue-4.9/cifs-reconnect-expired-smb-sessions.patch