On Sun, 5 Feb 2012 07:32:31 -0500 Jeff Layton <jlayton@xxxxxxxxxx> wrote: > On Fri, 3 Feb 2012 15:47:08 -0800 > Mark Moseley <moseleymark@xxxxxxxxx> wrote: > > > I've got a slew of Netapp Filers talking CIFS to some Debian Squeeze > > 64-bit boxes. I've noticed that in the kernel switch from 3.1 to 3.2, > > the clients are no longer able to unmount a CIFS volume from an older > > Filer. The Netapp versions in question are 7.2.7 and 7.0.6. I can > > unmount on a 3.2.x kernel from a 7.2.7 Filer just fine. With a 7.0.6 > > Filer, I get the following error printed to /proc/kmsg: > > > > <3>[ 277.363460] CIFS VFS: RFC1001 size 35 smaller than SMB for mid=12 > > <7>[ 277.363466] Bad SMB: : dump of 39 bytes of data at 0xffff880213e7e000 > > <7>[ 277.363472] 23000000 424d53ff 00000074 00018800 . . . # � S M B > > t . . . . . . . > > <7>[ 277.363478] 00000000 00000000 00000000 0e1000................<> > > 27338] 0c0000f0 > > > > but the umount call never returns, which makes reboots fun. I've > > replicated this on 3.2.1 and 3.2.2. I've seen it print the same "Bad > > SMB..." message as pasted above with 3.1.10 but the umount call > > returns successfully. And unmounting from the 7.2.7 Filers does not > > cause a "Bad SMB" message to get logged to /proc/kmsg. > > > > The client is still responsive, and I can run whatever would helpful > > to debug this. If I'm doing the unmount on the CLI, it hangs on the > > 'umount' syscall. If I kill the umount command, the mount is gone. As > > far as I can see, the unmount is succeeding, but for whatever reason, > > the umount system call isn't ever returning. Looking at a network > > dump, the last client call is for a logoff, which seems to succeed. > > > > There are no oops's or tracebacks logged. > > > > I can post my whole .config if it's helpful, though for brevity sake, > > here's the CIFS section: > > > > CONFIG_CIFS=m > > CONFIG_CIFS_STATS=y > > # CONFIG_CIFS_STATS2 is not set > > CONFIG_CIFS_WEAK_PW_HASH=y > > CONFIG_CIFS_UPCALL=y > > CONFIG_CIFS_XATTR=y > > CONFIG_CIFS_POSIX=y > > # CONFIG_CIFS_DEBUG2 is not set > > CONFIG_CIFS_DFS_UPCALL=y > > # CONFIG_CIFS_FSCACHE is not set > > # CONFIG_CIFS_ACL is not set > > > > Let me know what I can post to be of help here, or if I should repost > > to LKML, or if I should just dust off git bisect. Thanks! > > (cc'ing linux-cifs list too) > > NetApp filers have a long-standing (for years even) bug with their > handling of SMB_COM_LOGOFF_ANDX. The filer sends a malformed reply on > that command. cifs.ko tends to be a little more strict on checking the > various lengths in the packet than windows is so it tosses out the > reply. > > I'd suggest filing a bug with netapp on this. You can reference this > (ancient) RH bug if you need more ammo: > > https://bugzilla.redhat.com/show_bug.cgi?id=191112 > > Now, that said...I think we have a bug in cifs.ko here too. It's > throwing out these replies without waking up the thread that's waiting > on it, even though we were probably able to match it to a request. This > patch will probably fix it, but it's untested and I need to stare at it > a bit more to ensure that it doesn't cause any problems. > > In the meantime if you have a machine where you could test this, that > would be helpful. I'll plan to send it to Steve F. for inclusion in 3.3 > and stable once I've smoke tested it a bit more. > > Thanks, Revised patch. We want to return "length" if the mid wasn't ID'ed: -------------------------------[snip]------------------------------ cifs: don't return error from standard_receive3 after marking response malformed standard_receive3 will check the validity of the response from the server (via checkSMB). It'll pass the result of that check to handle_mid which will eventually dequeue it and mark it with a status of MID_RESPONSE_MALFORMED. At that point, it'll also return an error, which will make the demultiplex thread skip doing the callback for the mid. This is wrong -- if we were able to identify the request and the response is now malformed, then we want the demultiplex thread to do the callback. Fix this by making standard_receive3 return 0 in this situation. Cc: stable@xxxxxxxxxxxxxxx Reported-by: Mark Moseley <moseleymark@xxxxxxxxx> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> --- fs/cifs/connect.c | 7 ++++--- 1 files changed, 4 insertions(+), 3 deletions(-) diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index aa687c8..4759543 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -773,10 +773,11 @@ 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 (mid) - handle_mid(mid, server, smb_buffer, length); + if (!mid) + return length; - return length; + handle_mid(mid, server, smb_buffer, length); + return 0; } static int -- 1.7.7.6 -- Jeff Layton <jlayton@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
