Does msodsfs_readdir() require a exclusively locked vnode

[Rick Macklem]

Hi,

Currently both NFS servers set the vnode lock LK_SHARED
and so do the local syscalls (at least that's how it looks
by inspection?).

Peter Holm just posted me this panic, where a test for an
exclusive vnode lock fails in msdosfs_readdir().
KDB: stack backtrace:
db_trace_self_wrapper(c0efa6f6,c71627f8,c79230b0,c0f2ef29,f19154b8,...) at db_trace_self_wrapper+0x26
kdb_backtrace(c7f20b38,f19154fc,c0d586d5,f191550c,c7f20ae0,...) at kdb_backtrace+0x2a
vfs_badlock(c101b180,f191550c,c1055580,c7f20ae0) at vfs_badlock+0x23
assert_vop_elocked(c7f20ae0,c0ee5f4f,c09f3213,8,0,...) at assert_vop_elocked+0x55
pcbmap(c7966e00,0,f191560c,f1915618,f191561c,...) at pcbmap+0x45
msdosfs_readdir(f1915960,c0f4b343,c7f20ae0,f1915940,0,...) at msdosfs_readdir+0x528
VOP_READDIR_APV(c101b180,f1915960,2,f1915a68,c7923000,...) at VOP_READDIR_APV+0xc5
nfsrvd_readdir(f1915b64,0,c7f20ae0,c7923000,f1915a68,...) at nfsrvd_readdir+0x38e
nfsrvd_dorpc(f1915b64,0,c7923000,c842a200,4,...) at nfsrvd_dorpc+0x1f79
nfssvc_program(c7793800,c842a200,c0f24d67,492,0,...) at nfssvc_program+0x40f
svc_run_internal(f1915d14,c09d9a98,c73dfa80,f1915d28,c0ef1130,...) at svc_run_internal+0x952
svc_thread_start(c73dfa80,f1915d28,c0ef1130,3a5,c7e4b2c0,...) at svc_thread_start+0x10
fork_exit(c0bed7d0,c73dfa80,f1915d28) at fork_exit+0xb8
fork_trampoline() at fork_trampoline+0x8
--- trap 0x804c12e, eip = 0xc, esp = 0x33, ebp = 0x1 ---
pcbmap: 0xc7f20ae0 is not exclusive locked but should be
KDB: enter: lock violation

So, does anyone know if the msdosfs_readdir() really requires a LK_EXCLUSIVE
locked vnode or is the ASSERT_VOP_ELOCKED() too strong in pcbmap()?

rick