kern/139127: False negative vfs cache entry

[Peter Holm]

>Number:         139127
>Category:       kern
>Synopsis:       False negative vfs cache entry
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Fri Sep 25 09:00:10 UTC 2009
>Closed-Date:
>Last-Modified:
>Originator:     Peter Holm
>Release:        Current
>Organization:
The FreeBSD Project
>Environment:
FreeBSD x4.osted.lan 9.0-CURRENT FreeBSD 9.0-CURRENT #0 r197453: Thu Sep 24 12:52:32 CEST 2009     pho at x4.osted.lan:/usr/src/sys/i386/compile/PHO  i386
>Description:
$ ls -l /tmp/file.05015?
ls: /tmp/file.050150: No such file or directory
$ fsdb -r /dev/ad4s1e
** /dev/ad4s1e (NO WRITE)
Examining file system `/dev/ad4s1e'
Last Mounted on /tmp
current inode: directory
I=2 MODE=41777 SIZE=5120
        BTIME=May  7 05:54:47 2006 [0 nsec]
        MTIME=Apr  2 11:27:36 2009 [0 nsec]
        CTIME=Apr  2 11:27:36 2009 [0 nsec]
        ATIME=Apr  2 12:00:30 2009 [0 nsec]
OWNER=root GRP=wheel LINKCNT=35 FLAGS=0 BLKCNT=c GEN=65f71df4
fsdb (inum: 2)> lookup file.050150
component `file.050150': current inode: regular file
I=198 MODE=100600 SIZE=0
        BTIME=Apr  2 11:24:33 2009 [0 nsec]
        MTIME=Apr  2 11:24:33 2009 [0 nsec]
        CTIME=Apr  2 11:24:33 2009 [0 nsec]
        ATIME=Apr  2 11:24:33 2009 [0 nsec]
OWNER=pho GRP=wheel LINKCNT=1 FLAGS=0 BLKCNT=0 GEN=1deaab3a
fsdb (inum: 198)> quit
$ 

Consistency is restored by a umount + mount of the FS

>How-To-Repeat:
Test scenario at http://svn.freebsd.org/base/projects/stress2/misc/namecache.sh has to be run a few times to get the problem.
>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: