Re: WAPBL patch for testing

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

On Fri, Oct 31, 2008 at 10:01:36PM +0100, Joerg Sonnenberger wrote:
> On Fri, Oct 31, 2008 at 08:03:32PM +0100, Juergen Hannken-Illjes wrote:
> > The reason for these wapbl locks is ffs snapshots.  VOP_PUTPAGES() may
> > need to copy-on-write which needs to run inside a wapbl transaction
> > as we allocate blocks here.
> 
> Hm. I see. Can you try the attached patch?

...and a version that doesn't crash immediate if non-ufs filesystems are
used.

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 23:22:36 -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;
@@ -1210,8 +1198,6 @@ skip_scan:
        }
 
        if (has_trans) {
-               if (need_wapbl)
-                       WAPBL_END(vp->v_mount);
                fstrans_done(vp->v_mount);
        }
 
@@ -1283,6 +1269,8 @@ genfs_do_io(struct vnode *vp, off_t off,
        struct vnode *devvp;
        bool async = (flags & PGO_SYNCIO) == 0;
        bool write = rw == UIO_WRITE;
+       bool need_wapbl = (write && vp->v_mount && vp->v_mount->mnt_wapbl &&
+           (flags & PGO_JOURNALLOCKED) == 0);
        int brw = write ? B_WRITE : B_READ;
        UVMHIST_FUNC(__func__); UVMHIST_CALLED(ubchist);
 
@@ -1304,6 +1292,12 @@ genfs_do_io(struct vnode *vp, off_t off,
        skipbytes = 0;
        KASSERT(bytes != 0);
 
+       if (need_wapbl) {
+               error = WAPBL_BEGIN(vp->v_mount);
+               if (error)
+                       return error;
+       }
+
        if (write) {
                mutex_enter(&vp->v_interlock);
                vp->v_numoutput += 2;
@@ -1380,14 +1374,19 @@ genfs_do_io(struct vnode *vp, off_t off,
        nestiobuf_done(mbp, skipbytes, error);
        if (async) {
                UVMHIST_LOG(ubchist, "returning 0 (async)", 0,0,0,0);
-               return (0);
+               error = 0;
+       } else {
+               UVMHIST_LOG(ubchist, "waiting for mbp %p", mbp,0,0,0);
+               error = biowait(mbp);
+               s = splbio();
+               (*iodone)(mbp);
+               splx(s);
+               UVMHIST_LOG(ubchist, "returning, error %d", error,0,0,0);
        }
-       UVMHIST_LOG(ubchist, "waiting for mbp %p", mbp,0,0,0);
-       error = biowait(mbp);
-       s = splbio();
-       (*iodone)(mbp);
-       splx(s);
-       UVMHIST_LOG(ubchist, "returning, error %d", error,0,0,0);
+
+       if (need_wapbl)
+               WAPBL_END(vp->v_mount);
+
        return (error);
 }
 
@@ -1585,12 +1584,6 @@ 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 +1629,6 @@ genfs_directio(struct vnode *vp, struct 
                uio->uio_offset += len;
                uio->uio_resid -= len;
        }
-
-       if ((ioflag & IO_JOURNALLOCKED) == 0)
-               WAPBL_END(vp->v_mount);
 }
 
 /*