[PATCH] cifs: Do not init smb requests or block when sending requests

if cifsd thread is no longer running to demultixplex responses.

Do not send FindClose request when FindFirst failed without reaching end
of search. 

Signed-off-by: Steve French (sfrench@us.ibm.com)
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

5 files changed, 53 insertions, 7 deletions

diff --git a/fs/cifs/CHANGES b/fs/cifs/CHANGES
index bd3b55e1be17..4d2404305ab6 100644
--- a/fs/cifs/CHANGES
+++ b/fs/cifs/CHANGES
@@ -1,7 +1,10 @@
 Version 1.34
 ------------
 Fix error mapping of the TOO_MANY_LINKS (hardlinks) case.
-Do not oops if user kills cifs oplock kernel thread.
+Do not oops if root user kills cifs oplock kernel thread or
+kills the cifsd thread (NB: killing the cifs kernel threads is not
+recommended, unmount and rmmod cifs will kill them when they are
+no longer needed).
 
 Version 1.33
 ------------
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index f8edf816b4be..b004fef0a42b 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -90,7 +90,8 @@ small_smb_init(int smb_command, int wct, struct cifsTconInfo *tcon,
            check for tcp and smb session status done differently
            for those three - in the calling routine */
         if(tcon) {
-                if((tcon->ses) && (tcon->ses->server)){
+                if((tcon->ses) && (tcon->ses->status != CifsExiting) &&
+                                  (tcon->ses->server)){
                         struct nls_table *nls_codepage;
                                 /* Give Demultiplex thread up to 10 seconds to 
                                    reconnect, should be greater than cifs socket
@@ -185,7 +186,8 @@ smb_init(int smb_command, int wct, struct cifsTconInfo *tcon,
            check for tcp and smb session status done differently
            for those three - in the calling routine */
         if(tcon) {
-                if((tcon->ses) && (tcon->ses->server)){
+                if((tcon->ses) && (tcon->ses->status != CifsExiting) && 
+                                  (tcon->ses->server)){
                         struct nls_table *nls_codepage;
                                 /* Give Demultiplex thread up to 10 seconds to
                                    reconnect, should be greater than cifs socket
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 437be1efe99e..ac1f970e5369 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -604,7 +604,13 @@ multi_t2_fnd:
         spin_lock(&GlobalMid_Lock);
         server->tcpStatus = CifsExiting;
         server->tsk = NULL;
-        atomic_set(&server->inFlight, 0);
+        /* check if we have blocked requests that need to free */
+        /* Note that cifs_max_pending is normally 50, but
+        can be set at module install time to as little as two */
+        if(atomic_read(&server->inFlight) >= cifs_max_pending)
+                atomic_set(&server->inFlight, cifs_max_pending - 1);
+        /* We do not want to set the max_pending too low or we
+        could end up with the counter going negative */
         spin_unlock(&GlobalMid_Lock);
         /* Although there should not be any requests blocked on 
         this queue it can not hurt to be paranoid and try to wake up requests
@@ -640,6 +646,17 @@ multi_t2_fnd:
                 }
                 read_unlock(&GlobalSMBSeslock);
         } else {
+                /* although we can not zero the server struct pointer yet,
+                since there are active requests which may depnd on them,
+                mark the corresponding SMB sessions as exiting too */
+                list_for_each(tmp, &GlobalSMBSessionList) {
+                        ses = list_entry(tmp, struct cifsSesInfo,
+                                         cifsSessionList);
+                        if (ses->server == server) {
+                                ses->status = CifsExiting;
+                        }
+                }
+
                 spin_lock(&GlobalMid_Lock);
                 list_for_each(tmp, &server->pending_mid_q) {
                 mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
@@ -661,17 +678,34 @@ multi_t2_fnd:
         if (list_empty(&server->pending_mid_q)) {
                 /* mpx threads have not exited yet give them 
                 at least the smb send timeout time for long ops */
+                /* due to delays on oplock break requests, we need
+                to wait at least 45 seconds before giving up
+                on a request getting a response and going ahead
+                and killing cifsd */
                 cFYI(1, ("Wait for exit from demultiplex thread"));
-                msleep(46);
+                msleep(46000);
                 /* if threads still have not exited they are probably never
                 coming home not much else we can do but free the memory */
         }
-        kfree(server);
 
         write_lock(&GlobalSMBSeslock);
         atomic_dec(&tcpSesAllocCount);
         length = tcpSesAllocCount.counter;
+
+        /* last chance to mark ses pointers invalid
+        if there are any pointing to this (e.g
+        if a crazy root user tried to kill cifsd 
+        kernel thread explicitly this might happen) */
+        list_for_each(tmp, &GlobalSMBSessionList) {
+                ses = list_entry(tmp, struct cifsSesInfo,
+                                cifsSessionList);
+                if (ses->server == server) {
+                        ses->server = NULL;
+                }
+        }
         write_unlock(&GlobalSMBSeslock);
+
+        kfree(server);
         if(length  > 0) {
                 mempool_resize(cifs_req_poolp,
                         length + cifs_min_rcv,
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 1df26ddf68b1..dde2d251fc3d 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -512,7 +512,8 @@ int cifs_closedir(struct inode *inode, struct file *file)
                 pTcon = cifs_sb->tcon;
 
                 cFYI(1, ("Freeing private data in close dir"));
-                if (pCFileStruct->srch_inf.endOfSearch == FALSE) {
+                if ((pCFileStruct->srch_inf.endOfSearch == FALSE) &&
+                   (pCFileStruct->invalidHandle == FALSE)) {
                         pCFileStruct->invalidHandle = TRUE;
                         rc = CIFSFindClose(xid, pTcon, pCFileStruct->netfid);
                         cFYI(1, ("Closing uncompleted readdir with rc %d",
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index 79bf686a2a19..0046c219833d 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -270,6 +270,9 @@ CIFSSendRcv(const unsigned int xid, struct cifsSesInfo *ses,
 
   
 
+        if(ses->server->tcpStatus == CIFS_EXITING)
+                return -ENOENT;
+
         /* Ensure that we do not send more than 50 overlapping requests 
            to the same server. We may make this configurable later or
            use ses->maxReq */
@@ -401,6 +404,9 @@ SendReceive(const unsigned int xid, struct cifsSesInfo *ses,
                 return -EIO;
         }
 
+        if(ses->server->tcpStatus == CifsExiting)
+                return -ENOENT;
+
         /* Ensure that we do not send more than 50 overlapping requests 
            to the same server. We may make this configurable later or
            use ses->maxReq */