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CIFS: Reconnect expired SMB sessions

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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>
This commit is contained in:
Pavel Shilovsky 2017-07-08 14:32:00 -07:00 committed by Greg Kroah-Hartman
parent 28cbf06937
commit 92d7d3e867
4 changed files with 32 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
fs/cifs/cifsglob.h
View File

@ -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 *);

7
fs/cifs/cifssmb.c
View File

@ -1457,6 +1457,13 @@ 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);

7
fs/cifs/connect.c
View File

@ -796,6 +796,13 @@ 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;

16
fs/cifs/smb2ops.c
View File

@ -1018,6 +1018,18 @@ 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)
@ -1609,6 +1621,7 @@ 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,
@ -1690,6 +1703,7 @@ 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,
@ -1773,6 +1787,7 @@ 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,
@ -1862,6 +1877,7 @@ struct smb_version_operations smb311_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,