CVS commit: src/sys/kern

[David Young <dyoung%netbsd.org@localhost>]

Module Name:    src
Committed By:   dyoung
Date:           Fri Jul 10 23:07:55 UTC 2009

Modified Files:
        src/sys/kern: kern_lwp.c

Log Message:
In lwp_create(), take a reference to l2's filedesc_t instead of
taking a reference to curlwp's by calling fd_hold().  If lwp_create()
is called from fork1(), then l2 != curlwp, but l2's and not curlwp's
filedesc_t whose reference we should take.

This change stops the problem I describe in
<http://mail-index.netbsd.org/tech-kern/2009/07/09/msg005422.html>,
where /dev/rsd0a is never properly closed after fsck / runs on it.
This change seems to quiet my USB backup drive, sd0 at scsibus0 at
umass0, which had stopped spinning down when it was not in use:
The unit probably stayed open after mount(8) tried (and failed:
errant fstab entry) to mount it.

I am confident that this change is an improvement, but I doubt that
it is the last word on the matter.  I hate to get under the filedesc_t
abstraction by fiddling with fd_refcnt, and there may be something
I have missed, so somebody with greater understanding of the file
descriptors code should have a look.


To generate a diff of this commit:
cvs rdiff -u -r1.131 -r1.132 src/sys/kern/kern_lwp.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.