[linux-cifs-client] when a mounted remote smb server goes down - cifs vfs tries to re-connect - with strange side-effects
Jeff Layton
jlayton at samba.org
Tue Jan 5 05:18:04 MST 2010
On Tue, 5 Jan 2010 05:24:43 +0100
Günter Kukkukk <linux at kukkukk.com> wrote:
> Hi Jeff, Steve, ...
>
> I'm running here on opensuse 11.2 - tried default kernel - and now 2.6.33-rc2-0.1-default from latest cifs git.
>
> When mounting a remote smb server - and then that server goes down (just shutdown, no network cable unplugged),
> my client KDE4.x desktop becomes _very_ unresponsive - the (kicker) taskbar is now _unusable_ - no response
> at all - which also means that a user can't even use the GUI to shutdown.
>
> As soon i restart the remote smb server, all is fine again.
>
> Used many tools (like those from sysstat) - but at least CPU usage seem to be _not_ the problem.
>
> Could it be some kernel semaphores....?
>
> When the remote server is down, wireshark only shows some 3 seconds tcp/ip traffic on ports 139 and 445.
>
> From the cifs (debug 7) kernel log:
>
> Jan 5 04:38:01 linux300 kernel: [46253.309431] fs/cifs/inode.c: Getting info on //linux700/homegk
> Jan 5 04:38:01 linux300 kernel: [46253.309438] fs/cifs/cifssmb.c: In QPathInfo (Unix) the path //linux700/homegk
> Jan 5 04:38:04 linux300 kernel: [46256.080085] fs/cifs/connect.c: Socket created
> Jan 5 04:38:04 linux300 kernel: [46256.080740] fs/cifs/connect.c: Error -111 connecting to server via ipv4
> Jan 5 04:38:04 linux300 kernel: [46256.080770] fs/cifs/connect.c: reconnect error -111
> Jan 5 04:38:07 linux300 kernel: [46259.084106] fs/cifs/connect.c: Socket created
> Jan 5 04:38:07 linux300 kernel: [46259.084773] fs/cifs/connect.c: Error -111 connecting to server via ipv4
> Jan 5 04:38:07 linux300 kernel: [46259.084804] fs/cifs/connect.c: reconnect error -111
> Jan 5 04:38:10 linux300 kernel: [46262.088085] fs/cifs/connect.c: Socket created
> Jan 5 04:38:10 linux300 kernel: [46262.088728] fs/cifs/connect.c: Error -111 connecting to server via ipv4
> Jan 5 04:38:10 linux300 kernel: [46262.088758] fs/cifs/connect.c: reconnect error -111
> Jan 5 04:38:11 linux300 kernel: [46263.308062] fs/cifs/cifssmb.c: gave up waiting on reconnect in smb_init
> Jan 5 04:38:11 linux300 kernel: [46263.308082] fs/cifs/inode.c: error on getting revalidate info -112
> Jan 5 04:38:11 linux300 kernel: [46263.308090] fs/cifs/inode.c: cifs_revalidate - inode unchanged
> Jan 5 04:38:11 linux300 kernel: [46263.308102] fs/cifs/inode.c: CIFS VFS: leaving cifs_revalidate (xid = 224) rc =
> -112
> Jan 5 04:38:11 linux300 kernel: [46263.310204] fs/cifs/inode.c: CIFS VFS: in cifs_revalidate as Xid: 225 with uid:
> 1000
> Jan 5 04:38:11 linux300 kernel: [46263.310226] fs/cifs/inode.c: Revalidate: //linux700/homegk inode 0xf41c3e84 count 1
> dentry: 0xdaa7325c d_time 1951477551 jiffies 11490827
> Jan 5 04:38:11 linux300 kernel: [46263.310236] fs/cifs/inode.c: Getting info on //linux700/homegk
> Jan 5 04:38:11 linux300 kernel: [46263.310243] fs/cifs/cifssmb.c: In QPathInfo (Unix) the path //linux700/homegk
> Jan 5 04:38:13 linux300 kernel: [46265.092103] fs/cifs/connect.c: Socket created
> Jan 5 04:38:13 linux300 kernel: [46265.092744] fs/cifs/connect.c: Error -111 connecting to server via ipv4
> Jan 5 04:38:13 linux300 kernel: [46265.092774] fs/cifs/connect.c: reconnect error -111
> Jan 5 04:38:16 linux300 kernel: [46268.096101] fs/cifs/connect.c: Socket created
> Jan 5 04:38:16 linux300 kernel: [46268.096751] fs/cifs/connect.c: Error -111 connecting to server via ipv4
> Jan 5 04:38:16 linux300 kernel: [46268.096781] fs/cifs/connect.c: reconnect error -111
> Jan 5 04:38:19 linux300 kernel: [46271.100088] fs/cifs/connect.c: Socket created
> Jan 5 04:38:19 linux300 kernel: [46271.100729] fs/cifs/connect.c: Error -111 connecting to server via ipv4
> Jan 5 04:38:19 linux300 kernel: [46271.100758] fs/cifs/connect.c: reconnect error -111
> Jan 5 04:38:21 linux300 kernel: [46273.308054] fs/cifs/cifssmb.c: gave up waiting on reconnect in smb_init
> Jan 5 04:38:21 linux300 kernel: [46273.308075] fs/cifs/inode.c: error on getting revalidate info -112
> Jan 5 04:38:21 linux300 kernel: [46273.308083] fs/cifs/inode.c: cifs_revalidate - inode unchanged
> Jan 5 04:38:21 linux300 kernel: [46273.308097] fs/cifs/inode.c: CIFS VFS: leaving cifs_revalidate (xid = 225) rc =
> -112
> Jan 5 04:38:21 linux300 kernel: [46273.311877] fs/cifs/inode.c: CIFS VFS: in cifs_revalidate as Xid: 226 with uid:
> 1000
> Jan 5 04:38:21 linux300 kernel: [46273.311901] fs/cifs/inode.c: Revalidate: //linux700/homegk inode 0xf41c3e84 count 1
> dentry: 0xdaa7325c d_time 1951477551 jiffies 11493327
> Jan 5 04:38:21 linux300 kernel: [46273.311912] fs/cifs/inode.c: Getting info on //linux700/homegk
>
Most likely the problem is that you have programs that are trying to
repeatedly access the CIFS share while the server is down. The kernel
looks like it's doing what it's supposed to do, which is to attempt to
reconnect to the server so it can satisfy the syscall.
It looks like the program is just retrying the syscall over and over
here, but you might want to try and verify that by stracing the program
(if you can track it down). If so, then there's not much we can do at
the kernel level. You might be able to get away with doing a lazy umount
(umount -l) to work around it if the program is retrying the syscalls.
--
Jeff Layton <jlayton at samba.org>
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