CVS commit: [netbsd-5] src/sys/kern

[Stephen Borrill <sborrill%netbsd.org@localhost>]

Module Name:    src
Committed By:   sborrill
Date:           Sat Nov 28 18:59:11 UTC 2009

Modified Files:
        src/sys/kern [netbsd-5]: vfs_subr.c

Log Message:
Pull up the following revisions(s) (requested by bouyer in ticket #1171):
        sys/kern/vfs_subr.c:    revision 1.392

Previous caused a deadlock with layered FS: the vrele thread can sleep on
the vnode lock, while vget is sleeping on the VI_INACTNOW flag (or the vget
caller is looping on vget returning failure because of the VI_INACTNOW
flag). With layered FSes, the upper and lower vnodes share the same lock, so
the vget() caller above can be already holding the vnode lock.

Fix by dropping VI_INACTNOW before sleeping on the vnode lock in
vrelel(), and check the ref count again once we have the lock. If the
vnode has more than one reference, don't VOP_INACTIVE it.
Fix PR kern/42318 and PR kern/42377


To generate a diff of this commit:
cvs rdiff -u -r1.357.4.7 -r1.357.4.8 src/sys/kern/vfs_subr.c

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