Writes greater than 64k fails with -ENOSPC

[Suresh Jayaraman <sjayaraman-IBi9RG/b67k@public.gmane.org>]

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

-- 
Suresh Jayaraman