CIFS: Reconnect expired SMB sessions

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@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 99745da9cd90a30f77102b1b279b9ebb53fe103d..0a359af59dd89d9f90917785bca2b4d59081ba98 100644 (file)
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -347,6 +347,8 @@ 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 *);

diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 8e1a17c64ddd23335181400c20dfc36eac95a1fc..b2218b755dab7019c3fb2f4de1bdcb0540812f93 100644 (file)
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -1458,6 +1458,13 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
                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);

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 43df8c3e026c3d63c2f1bbc01a34142bbfff4e2a..43bb9e2c81a5d203ffb26a5a28254eb5e35ce0cf 100644 (file)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -839,6 +839,13 @@ standard_receive3(struct TCP_Server_Info *server, struct mid_q_entry *mid)
                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;

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 881af94ac68f8ce87e186492255a415e89764af3..d23a41652b4c7e617a742c8c615ba0cab44d7fa5 100644 (file)
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -896,6 +896,18 @@ smb2_is_status_pending(char *buf, struct TCP_Server_Info *server, int length)
        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)
@@ -1424,6 +1436,7 @@ struct smb_version_operations smb20_operations = {
        .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,
@@ -1505,6 +1518,7 @@ struct smb_version_operations smb21_operations = {
        .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,
@@ -1587,6 +1601,7 @@ struct smb_version_operations smb30_operations = {
        .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,