kern/88266: smbfs does not implement UIO_NOCOPY and sendfile(2) on smbfs mounted files fails

[Niki Denev]

>Number:         88266
>Category:       kern
>Synopsis:       smbfs does not implement UIO_NOCOPY and sendfile(2) on smbfs mounted files fails
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Oct 31 07:40:07 GMT 2005
>Closed-Date:
>Last-Modified:
>Originator:     Niki Denev
>Release:        5.4-STABLE and 6.0-RC1
>Organization:
>Environment:
FreeBSD tormentor.totalterror.net 6.0-RC1 FreeBSD 6.0-RC1 #0: Sun Oct 30 18:19:53 EET 2005     root at tormentor.totalterror.net:/usr/src/sys/i386/compile/SMP  i386
>Description:
smbfs does not implement UIO_NOCOPY (zerocopy) and if receives request for 
such will return with error and set errno to EOPNOTSUPP, which was until now undocumented.
This means that many popular web and ftp servers which implement sendfile(2) could
have problems when serving files from smbfs mounts if they not have handling for 
this case and fallback to another method, but as the errno code was undocumented 
probably there are not much as of now.

>How-To-Repeat:
Mount some smbfs share to a directory that is served for example with the www/lighttpd port.
Trying to download them via http will result in 0 byte documents.

>Fix:
none
>Release-Note:
>Audit-Trail:
>Unformatted: