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cifs: eliminate some more premature cifsd exits

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If the tcpStatus is still CifsNew, the main cifs_demultiplex_loop can
break out prematurely in some cases. This is wrong as we will almost
always have other structures with pointers to the TCP_Server_Info. If
the main loop breaks under any other condition other than tcpStatus ==
CifsExiting, then it'll face a use-after-free situation.

I don't see any reason to treat a CifsNew tcpStatus differently than
CifsGood. I believe we'll still want to attempt to reconnect in either
case. What should happen in those situations is that the MIDs get marked
as MID_RETRY_NEEDED. This will make CIFSSMBNegotiate return -EAGAIN, and
then the caller can retry the whole thing on a newly reconnected socket.
If that fails again in the same way, the caller of cifs_get_smb_ses
should tear down the TCP_Server_Info struct.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
This commit is contained in:
Jeff Layton 2010-09-03 12:00:49 -04:00 committed by Steve French
parent 522bbe65a2
commit 7332f2a621
1 changed files with 12 additions and 29 deletions
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41
fs/cifs/connect.c
View file

@ -416,14 +416,6 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server)
} else } else
continue; continue;
} else if (length <= 0) { } else if (length <= 0) {
if (server->tcpStatus == CifsNew) {
cFYI(1, "tcp session abend after SMBnegprot");
/* some servers kill the TCP session rather than
returning an SMB negprot error, in which
case reconnecting here is not going to help,
and so simply return error to mount */
break;
}
cFYI(1, "Reconnect after unexpected peek error %d", cFYI(1, "Reconnect after unexpected peek error %d",
length); length);
cifs_reconnect(server); cifs_reconnect(server);
@ -464,27 +456,18 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server)
an error on SMB negprot response */ an error on SMB negprot response */
cFYI(1, "Negative RFC1002 Session Response Error 0x%x)", cFYI(1, "Negative RFC1002 Session Response Error 0x%x)",
pdu_length); pdu_length);
if (server->tcpStatus == CifsNew) { /* give server a second to clean up */
/* if nack on negprot (rather than msleep(1000);
ret of smb negprot error) reconnecting /* always try 445 first on reconnect since we get NACK
not going to help, ret error to mount */ * on some if we ever connected to port 139 (the NACK
break; * is since we do not begin with RFC1001 session
} else { * initialize frame)
/* give server a second to */
clean up before reconnect attempt */ server->addr.sockAddr.sin_port = htons(CIFS_PORT);
msleep(1000); cifs_reconnect(server);
/* always try 445 first on reconnect csocket = server->ssocket;
since we get NACK on some if we ever wake_up(&server->response_q);
connected to port 139 (the NACK is continue;
since we do not begin with RFC1001
session initialize frame) */
server->addr.sockAddr.sin_port =
htons(CIFS_PORT);
cifs_reconnect(server);
csocket = server->ssocket;
wake_up(&server->response_q);
continue;
}
} else if (temp != (char) 0) { } else if (temp != (char) 0) {
cERROR(1, "Unknown RFC 1002 frame"); cERROR(1, "Unknown RFC 1002 frame");
cifs_dump_mem(" Received Data: ", (char *)smb_buffer, cifs_dump_mem(" Received Data: ", (char *)smb_buffer,