On Tue, 29 Jan 2013 17:54:21 +0530
Suresh Jayaraman <sjayaraman@xxxxxxxx> wrote:
> Hi all,
>
> I'm looking into a report on 3.0 based kernel (plus stable fixes)
> where writes greater than 64k to a NAS (Hitachi NAS) is failing
> (simple dd). The problem was not seen with a 2.6.32-ish kernel.
> Also, note that the problem is not seen with other Servers such
> as Windows 2003 or Windows 8 Servers.
>
> The strace output shows the close() fall fails with -ENOSPC.
>
> The relevant cFYI snip
>
> Jan 23 08:31:45 vsusix02 kernel: [1003552.227274] /usr/src/packages/BUILD/kernel-default-3.0.42/linux-3.0/fs/cifs/transport.c: For smb_command 47
> Jan 23 08:31:45 vsusix02 kernel: [1003552.227277] /usr/src/packages/BUILD/kernel-default-3.0.42/linux-3.0/fs/cifs/transport.c: Sending smb: total_len 127044
> Jan 23 08:31:45 vsusix02 kernel: [1003552.345848] /usr/src/packages/BUILD/kernel-default-3.0.42/linux-3.0/fs/cifs/connect.c: rfc1002 length 0x33
> Jan 23 08:31:45 vsusix02 kernel: [1003552.393906] /usr/src/packages/BUILD/kernel-default-3.0.42/linux-3.0/fs/cifs/cifssmb.c: async write at 1015808 8192 bytes
> Jan 23 08:31:45 vsusix02 kernel: [1003552.393911] /usr/src/packages/BUILD/kernel-default-3.0.42/linux-3.0/fs/cifs/transport.c: For smb_command 47
> Jan 23 08:31:45 vsusix02 kernel: [1003552.393914] /usr/src/packages/BUILD/kernel-default-3.0.42/linux-3.0/fs/cifs/transport.c: Sending smb: total_len 8260
> Jan 23 08:31:45 vsusix02 kernel: [1003552.479378] /usr/src/packages/BUILD/kernel-default-3.0.42/linux-3.0/fs/cifs/connect.c: rfc1002 length 0x33
> Jan 23 08:31:45 vsusix02 kernel: [1003552.481215] /usr/src/packages/BUILD/kernel-default-3.0.42/linux-3.0/fs/cifs/connect.c: rfc1002 length 0x33
> Jan 23 08:31:45 vsusix02 kernel: [1003552.481260] /usr/src/packages/BUILD/kernel-default-3.0.42/linux-3.0/fs/cifs/file.c: Flush inode ffff88004e1655c0 file ffff8800379d48c0 rc -28
>
>
> The problem seems to be that during close(), we try to flush the
> buffers by calling cifs_flush() which in turn will call
> filemap_write_and_wait() to wait on the pages under writeback to
> complete. do_writepages() will invoke cifs_writepages() which is
> perhaps returning -ENOSPC and it is propagated back.
>
> There are no quota restrictions or disk space problems. The
> tcpdump output doesn't show any errors during the write or close.
>
> I'm not sure what could be causing the problem and would
> appreciate any clues or debugging suggestions.
>
> Thanks
>
I'd look for "short" write replies. We have this in
cifs_writev_callback:
if (written < wdata->bytes)
wdata->result = -ENOSPC;
IIRC, this is spelled out in MS-CIFS in the section on WRITE_ANDX
responses, but I remember it not being 100% clear...
--
Jeff Layton <jlayton@xxxxxxxxxx>
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