On Sun, Feb 5, 2012 at 1:10 PM, Jeff Layton <jlayton@xxxxxxxxxx> wrote: > 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(-) Awesome, thanks for the info and thanks for the patch. I can confirm it works just fine. The umount syscall comes back immediately and everything looks good. I'll see what Netapp says, though hopefully we'll be off of 7.0.6 soon anyway. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
