[src/trunk]: src/sys/coda Fixes from get/putpages from rmind.

[christos <christos%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/5d46a69ae13f
branches:  trunk
changeset: 779046:5d46a69ae13f
user:      christos <christos%NetBSD.org@localhost>
date:      Sat Apr 28 20:01:09 2012 +0000

description:
Fixes from get/putpages from rmind.
In grab vnode, share the lock of the coda vnode with the underlying vnode,
so that the locking protocol works.

diffstat:

 sys/coda/coda_vnops.c |  54 +++++++++++++++++++++++++++-----------------------
 sys/coda/coda_vnops.h |  13 +++++------
 2 files changed, 35 insertions(+), 32 deletions(-)

diffs (200 lines):

diff -r eca4fe94fdd8 -r 5d46a69ae13f sys/coda/coda_vnops.c
--- a/sys/coda/coda_vnops.c     Sat Apr 28 18:04:02 2012 +0000
+++ b/sys/coda/coda_vnops.c     Sat Apr 28 20:01:09 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: coda_vnops.c,v 1.82 2012/04/26 03:04:54 christos Exp $ */
+/*     $NetBSD: coda_vnops.c,v 1.83 2012/04/28 20:01:09 christos Exp $ */
 
 /*
  *
@@ -46,7 +46,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: coda_vnops.c,v 1.82 2012/04/26 03:04:54 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: coda_vnops.c,v 1.83 2012/04/28 20:01:09 christos Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -250,7 +250,7 @@
      * Obtain locked and referenced container vnode from container
      * device/inode.
      */
-    error = coda_grab_vnode(dev, inode, &container_vp);
+    error = coda_grab_vnode(vp, dev, inode, &container_vp);
     if (error)
        return (error);
 
@@ -425,7 +425,7 @@
        if (cp->c_inode != 0 && !(p && (p->p_acflag & ACORE))) {
            printf("coda_rdwr: grabbing container vnode, losing reference\n");
            /* Get locked and refed vnode. */
-           error = coda_grab_vnode(cp->c_device, cp->c_inode, &cfvp);
+           error = coda_grab_vnode(vp, cp->c_device, cp->c_inode, &cfvp);
            if (error) {
                MARK_INT_FAIL(CODA_RDWR_STATS);
                return(error);
@@ -1791,7 +1791,7 @@
  * obtained and passed back to the caller.
  */
 int
-coda_grab_vnode(dev_t dev, ino_t ino, struct vnode **vpp)
+coda_grab_vnode(struct vnode *uvp, dev_t dev, ino_t ino, struct vnode **vpp)
 {
     int           error;
     struct mount *mp;
@@ -1814,6 +1814,10 @@
            (unsigned long long)dev, (unsigned long long)ino, *vpp, error));
        return(ENOENT);
     }
+    /* share the lock with the underlying vnode */
+    mutex_obj_hold(uvp->v_interlock);
+    uvm_obj_setlock(&(*vpp)->v_uobj, uvp->v_interlock);
+
     return(0);
 }
 
@@ -1934,8 +1938,6 @@
  * e.g. to fault in pages to execute a program.  In that case, we must
  * open the file to get the container.  The vnode may or may not be
  * locked, and we must leave it in the same state.
- * XXX The protocol requires v_uobj.vmobjlock to be
- * held by caller, but this isn't documented in vnodeops(9) or vnode_if.src.
  */
 int
 coda_getpages(void *v)
@@ -1950,7 +1952,7 @@
                int a_advice;
                int a_flags;
        } */ *ap = v;
-       struct vnode *vp = ap->a_vp;
+       struct vnode *vp = ap->a_vp, *cvp;
        struct cnode *cp = VTOC(vp);
        struct lwp *l = curlwp;
        kauth_cred_t cred = l->l_cred;
@@ -1958,6 +1960,8 @@
        int waslocked;         /* 1 if vnode lock was held on entry */
        int didopen = 0;        /* 1 if we opened container file */
 
+       KASSERT(mutex_owned(vp->v_interlock));
+
        /*
         * Handle a case that uvm_fault doesn't quite use yet.
         * See layer_vnops.c. for inspiration.
@@ -1969,7 +1973,6 @@
        /* Check for control object. */
        if (IS_CTL_VP(vp)) {
                printf("coda_getpages: control object %p\n", vp);
-               mutex_exit(vp->v_uobj.vmobjlock);
                return(EINVAL);
        }
 
@@ -1984,11 +1987,9 @@
        /* XXX VOP_ISLOCKED() may not be used for lock decisions. */
        waslocked = VOP_ISLOCKED(vp);
 
-       /* Drop the vmobject lock. */
-       mutex_exit(vp->v_uobj.vmobjlock);
-
        /* Get container file if not already present. */
-       if (cp->c_ovp == NULL) {
+       cvp = cp->c_ovp;
+       if (cvp == NULL) {
                /*
                 * VOP_OPEN requires a locked vnode.  We must avoid
                 * locking the vnode if it is already locked, and
@@ -2025,15 +2026,16 @@
 #if 0
                printf("coda_getpages: opened vnode %p\n", vp);
 #endif
+               cvp = cp->c_ovp;
                didopen = 1;
        }
-       KASSERT(cp->c_ovp != NULL);
+       KASSERT(cvp != NULL);
 
        /* Munge the arg structure to refer to the container vnode. */
+       KASSERT(cvp->v_interlock == vp->v_interlock);
        ap->a_vp = cp->c_ovp;
 
-       /* Get the lock on the container vnode, and call getpages on it. */
-       mutex_enter(ap->a_vp->v_uobj.vmobjlock);
+       /* Finally, call getpages on it. */
        error = VCALL(ap->a_vp, VOFFSET(vop_getpages), ap);
 
        /* If we opened the vnode, we must close it. */
@@ -2057,8 +2059,7 @@
 }
 
 /*
- * The protocol requires v_uobj.vmobjlock to be held by the caller, as
- * documented in vnodeops(9).  XXX vnode_if.src doesn't say this.
+ * The protocol requires v_interlock to be held by the caller.
  */
 int
 coda_putpages(void *v)
@@ -2069,15 +2070,15 @@
                voff_t a_offhi;
                int a_flags;
        } */ *ap = v;
-       struct vnode *vp = ap->a_vp;
+       struct vnode *vp = ap->a_vp, *cvp;
        struct cnode *cp = VTOC(vp);
        int error;
 
-       /* Drop the vmobject lock. */
-       mutex_exit(vp->v_uobj.vmobjlock);
+       KASSERT(mutex_owned(vp->v_interlock));
 
        /* Check for control object. */
        if (IS_CTL_VP(vp)) {
+               mutex_exit(vp->v_interlock);
                printf("coda_putpages: control object %p\n", vp);
                return(EINVAL);
        }
@@ -2088,14 +2089,17 @@
         * time, apparently during discard of a closed vnode (which
         * trivially can't have dirty pages).
         */
-       if (cp->c_ovp == NULL)
+       cvp = cp->c_ovp;
+       if (cvp == NULL) {
+               mutex_exit(vp->v_interlock);
                return 0;
+       }
 
        /* Munge the arg structure to refer to the container vnode. */
-       ap->a_vp = cp->c_ovp;
+       KASSERT(cvp->v_interlock == vp->v_interlock);
+       ap->a_vp = cvp;
 
-       /* Get the lock on the container vnode, and call putpages on it. */
-       mutex_enter(ap->a_vp->v_uobj.vmobjlock);
+       /* Finally, call putpages on it. */
        error = VCALL(ap->a_vp, VOFFSET(vop_putpages), ap);
 
        return error;
diff -r eca4fe94fdd8 -r 5d46a69ae13f sys/coda/coda_vnops.h
--- a/sys/coda/coda_vnops.h     Sat Apr 28 18:04:02 2012 +0000
+++ b/sys/coda/coda_vnops.h     Sat Apr 28 20:01:09 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: coda_vnops.h,v 1.13 2006/05/14 21:24:49 elad Exp $     */
+/*     $NetBSD: coda_vnops.h,v 1.14 2012/04/28 20:01:09 christos Exp $ */
 
 /*
  *
@@ -80,9 +80,8 @@
 int coda_putpages(void *);
 
 int (**coda_vnodeop_p)(void *);
-int coda_rdwr(struct vnode *vp, struct uio *uiop, enum uio_rw rw,
-    int ioflag, kauth_cred_t cred, struct lwp *l);
-
-int coda_grab_vnode(dev_t dev, ino_t ino, struct vnode **vpp);
-void print_vattr(struct vattr *attr);
-void print_cred(kauth_cred_t cred);
+int coda_rdwr(vnode_t *, struct uio *, enum uio_rw, int, kauth_cred_t,
+    struct lwp *);
+int coda_grab_vnode(vnode_t *, dev_t, ino_t, vnode_t **);
+void print_vattr(struct vattr *);
+void print_cred(kauth_cred_t);