From 1be912dde772b77aaaa21770eeabb0a7a5e297a6 Mon Sep 17 00:00:00 2001
From: Jeff Layton <jlayton@redhat.com>
Date: Fri, 28 Jan 2011 07:08:28 -0500
Subject: [PATCH] cifs: handle cancelled requests better
Currently, when a request is cancelled via signal, we delete the mid
immediately. If the request was already transmitted however, the client
is still likely to receive a response. When it does, it won't recognize
it however and will pop a printk.
It's also a little dangerous to just delete the mid entry like this. We
may end up reusing that mid. If we do then we could potentially get the
response from the first request confused with the later one.
Prevent the reuse of mids by marking them as cancelled and keeping them
on the pending_mid_q list. If the reply comes in, we'll delete it from
the list then. If it never comes, then we'll delete it at reconnect
or when cifsd comes down.
Reviewed-by: Pavel Shilovsky <piastryyy@gmail.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
---
fs/cifs/transport.c | 43 ++++++++++++++++++++++++++++++++++++-------
1 file changed, 36 insertions(+), 7 deletions(-)
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index c1ccca1a933f..9b2d0373a8a7 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -579,8 +579,17 @@ SendReceive2(const unsigned int xid, struct cifsSesInfo *ses,
goto out;
rc = wait_for_response(ses->server, midQ);
- if (rc != 0)
- goto out;
+ if (rc != 0) {
+ spin_lock(&GlobalMid_Lock);
+ if (midQ->midState == MID_REQUEST_SUBMITTED) {
+ midQ->callback = DeleteMidQEntry;
+ spin_unlock(&GlobalMid_Lock);
+ atomic_dec(&ses->server->inFlight);
+ wake_up(&ses->server->request_q);
+ return rc;
+ }
+ spin_unlock(&GlobalMid_Lock);
+ }
rc = sync_mid_result(midQ, ses->server);
if (rc != 0) {
@@ -724,8 +733,18 @@ SendReceive(const unsigned int xid, struct cifsSesInfo *ses,
goto out;
rc = wait_for_response(ses->server, midQ);
- if (rc != 0)
- goto out;
+ if (rc != 0) {
+ spin_lock(&GlobalMid_Lock);
+ if (midQ->midState == MID_REQUEST_SUBMITTED) {
+ /* no longer considered to be "in-flight" */
+ midQ->callback = DeleteMidQEntry;
+ spin_unlock(&GlobalMid_Lock);
+ atomic_dec(&ses->server->inFlight);
+ wake_up(&ses->server->request_q);
+ return rc;
+ }
+ spin_unlock(&GlobalMid_Lock);
+ }
rc = sync_mid_result(midQ, ses->server);
if (rc != 0) {
@@ -922,10 +941,20 @@ SendReceiveBlockingLock(const unsigned int xid, struct cifsTconInfo *tcon,
}
}
- if (wait_for_response(ses->server, midQ) == 0) {
- /* We got the response - restart system call. */
- rstart = 1;
+ rc = wait_for_response(ses->server, midQ);
+ if (rc) {
+ spin_lock(&GlobalMid_Lock);
+ if (midQ->midState == MID_REQUEST_SUBMITTED) {
+ /* no longer considered to be "in-flight" */
+ midQ->callback = DeleteMidQEntry;
+ spin_unlock(&GlobalMid_Lock);
+ return rc;
+ }
+ spin_unlock(&GlobalMid_Lock);
}
+
+ /* We got the response - restart system call. */
+ rstart = 1;
}
rc = sync_mid_result(midQ, ses->server);