WAPBL patch for testing

[Joerg Sonnenberger <joerg%britannica.bec.de@localhost>]

Hi all,
the attached patch is supposed to fix both hangs (wchan tstile) and
performance issues with WAPBL. Please test it and report any issues.
I'd like to see some review for this too. I can't find a reason why the
WAPBL lock should be hold in that places nor can I find a code path from
UFS itself to getpages with lock already being hold, but I could be
wrong.

Joerg

Index: genfs_io.c
===================================================================
RCS file: /home/joerg/repo/netbsd/src/sys/miscfs/genfs/genfs_io.c,v
retrieving revision 1.13
diff -u -p -r1.13 genfs_io.c
--- genfs_io.c  19 Oct 2008 18:17:13 -0000      1.13
+++ genfs_io.c  31 Oct 2008 01:53:36 -0000
@@ -779,7 +779,6 @@ genfs_do_putpages(struct vnode *vp, off_
        int flags;
        int dirtygen;
        bool modified;
-       bool need_wapbl;
        bool has_trans;
        bool cleanall;
        bool onworklst;
@@ -794,8 +793,6 @@ genfs_do_putpages(struct vnode *vp, off_
            vp, uobj->uo_npages, startoff, endoff - startoff);
 
        has_trans = false;
-       need_wapbl = (!pagedaemon && vp->v_mount && vp->v_mount->mnt_wapbl &&
-           (origflags & PGO_JOURNALLOCKED) == 0);
 
 retry:
        modified = false;
@@ -809,8 +806,6 @@ retry:
                                vn_syncer_remove_from_worklist(vp);
                }
                if (has_trans) {
-                       if (need_wapbl)
-                               WAPBL_END(vp->v_mount);
                        fstrans_done(vp->v_mount);
                }
                mutex_exit(slock);
@@ -829,13 +824,6 @@ retry:
                                return error;
                } else
                        fstrans_start(vp->v_mount, FSTRANS_LAZY);
-               if (need_wapbl) {
-                       error = WAPBL_BEGIN(vp->v_mount);
-                       if (error) {
-                               fstrans_done(vp->v_mount);
-                               return error;
-                       }
-               }
                has_trans = true;
                mutex_enter(slock);
                goto retry;
@@ -958,6 +946,7 @@ retry:
                                mutex_enter(slock);
                        } else {
                                pg->flags |= PG_WANTED;
+                               printf(".");
                                UVM_UNLOCK_AND_WAIT(pg, slock, 0, "genput", 0);
                                mutex_enter(slock);
                        }
@@ -1210,8 +1199,6 @@ skip_scan:
        }
 
        if (has_trans) {
-               if (need_wapbl)
-                       WAPBL_END(vp->v_mount);
                fstrans_done(vp->v_mount);
        }
 
@@ -1585,12 +1572,6 @@ genfs_directio(struct vnode *vp, struct 
                return;
        }
 
-       if ((ioflag & IO_JOURNALLOCKED) == 0) {
-               error = WAPBL_BEGIN(vp->v_mount);
-               if (error)
-                       return;
-       }
-
        /*
         * Do as much of the uio as possible with direct I/O.
         */
@@ -1636,9 +1617,6 @@ genfs_directio(struct vnode *vp, struct 
                uio->uio_offset += len;
                uio->uio_resid -= len;
        }
-
-       if ((ioflag & IO_JOURNALLOCKED) == 0)
-               WAPBL_END(vp->v_mount);
 }
 
 /*