CVS commit: src/sys/kern

["Juergen Hannken-Illjes" <hannken%netbsd.org@localhost>]

Module Name:    src
Committed By:   hannken
Date:           Sun Oct  2 13:00:07 UTC 2011

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

Log Message:
The path getnewvnode()->getcleanvnode()->vclean()->VOP_LOCK() will panic
if the vnode we want to clean is a layered vnode and the caller already
locked its lower vnode.

Change getnewvnode() to always allocate a fresh vnode and add a helper
thread (vdrain) to keep the number of allocated vnodes within desiredvnodes.

Rename getcleanvnode() to cleanvnode() and let it take a vnode from the
lists, clean and free it.

Reviewed by: David Holland <dholland%netbsd.org@localhost>

Should fix:
PR #19110 (nullfs mounts over NFS cause lock manager problems)
PR #34102 (ffs panic in NetBSD 3.0_STABLE)
PR #45115 (lock error panic when build.sh*3 and daily script is running)
PR #45355 (Reader/writer lock error:  rw_vector_enter: locking against myself)


To generate a diff of this commit:
cvs rdiff -u -r1.11 -r1.12 src/sys/kern/vfs_vnode.c

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