Package: smbfs Version: 3.0.10-1 Severity: normal Documentation and/or functionality of the rsize and wsize options to mount.cifs is faulty.
Rsize and wsize are documented just as "network read/write size" without reference to units or any explanation of what this really means. Trawling through the kernel cifs module code I found a restriction that the parameters must be in multiples of 4096, a page size. But cat /proc/mounts says that the default values are 4100, so 4 somethings (bytes, blocks, or whatever) are unaccounted for. Also, I can't seem to change the number from 4100. If I use the -v option to mount, I can see that my option requests are being parsed properly, but /proc/mounts always reports 4100 even if I try mounting with, say, rsize=9000 (that is, 2*4096 with a few extra thrown in). I can make a guess that rsize/wsize and the MTU of the interface are interdependent in some way. Observing packet sizes with tcpdump, over an interface with MTU 8000, I observe packet sizes of 4218 or 4214 bytes. Having mounted a share at, say, /winshare, I tried operations like "cat /winshare/largefile >/dev/null" or "cp /tmp/largefile /winshare". A Samba server running over the same interface used packets with size 8014, so the smaller packet size of 4214/4218 xferred over the CIFS mount is specific to the CIFS mount; because the numbers are close, the packet size of 4214/4218 seems to be related to the rsize/wsize of 4100. Setting the MTU of the interface to 1500 reduced the packet sizes over the mount to about the MTU size. In summary, in the process of trying to get traffic over a CIFS mount to use jumbo packets (on a network that has already been shown to handle them properly), I have found (1) that I cannot set rsize/wsize with mount options as I expect, and (2) that the documentation of rsize/wsize is insufficient. -- System Information: Debian Release: 3.1 APT prefers testing APT policy: (500, 'testing') Architecture: i386 (i686) Kernel: Linux 2.6.8-beth.10 Locale: LANG=en_US, LC_CTYPE=en_US (charmap=ISO-8859-1) Versions of packages smbfs depends on: ii libc6 2.3.2.ds1-20 GNU C Library: Shared libraries an ii libcomerr2 1.35-6 The Common Error Description libra ii libkrb53 1.3.6-1 MIT Kerberos runtime libraries ii libldap2 2.1.30-3 OpenLDAP libraries ii netbase 4.19 Basic TCP/IP networking system ii samba-common 3.0.10-1 Samba common files used by both th -- no debconf information -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
