Since the VFS_LOCK_GIANT() code in the experimental NFS

server is broken and the major file systems are now all
mpsafe, modify the server so that it will only export
mpsafe file systems. This was discussed on freebsd-fs@
and removes a fair bit of crufty code.

MFC after:	12 days

5 files changed, 54 insertions, 171 deletions

diff --git a/sys/fs/nfs/nfs_var.h b/sys/fs/nfs/nfs_var.h
index 782630b..2dbbdda 100644
--- a/sys/fs/nfs/nfs_var.h
+++ b/sys/fs/nfs/nfs_var.h
@@ -570,8 +570,6 @@ int nfsvno_pathconf(vnode_t, int, register_t *, struct ucred *,
     NFSPROC_T *);
 vnode_t nfsvno_getvp(fhandle_t *);
 int nfsvno_advlock(vnode_t, int, u_int64_t, u_int64_t, NFSPROC_T *);
-void nfsvno_unlockvfs(mount_t);
-int nfsvno_lockvfs(mount_t);
 int nfsrv_v4rootexport(void *, struct ucred *, NFSPROC_T *);
 int nfsvno_testexp(struct nfsrv_descript *, struct nfsexstuff *);
 uint32_t nfsrv_hashfh(fhandle_t *);
diff --git a/sys/fs/nfs/nfsdport.h b/sys/fs/nfs/nfsdport.h
index 4888866..a3f05db 100644
--- a/sys/fs/nfs/nfsdport.h
+++ b/sys/fs/nfs/nfsdport.h
@@ -52,7 +52,6 @@
  * needs to be returned by nfsd_fhtovp().
  */
 struct nfsexstuff {
-	int	nes_vfslocked;			/* required for all ports */
 	int	nes_exflag;			/* export flags */
 	int	nes_numsecflavor;		/* # of security flavors */
 	int	nes_secflavors[MAXSECFLAVORS];	/* and the flavors */
diff --git a/sys/fs/nfsserver/nfs_nfsdport.c b/sys/fs/nfsserver/nfs_nfsdport.c
index 8201efc..4a03f4b 100644
--- a/sys/fs/nfsserver/nfs_nfsdport.c
+++ b/sys/fs/nfsserver/nfs_nfsdport.c
@@ -332,18 +332,7 @@ nfsvno_namei(struct nfsrv_descript *nd, struct nameidata *ndp,
 		 * In either case ni_startdir will be dereferenced and NULLed
 		 * out.
 		 */
-		if (exp->nes_vfslocked)
-			ndp->ni_cnd.cn_flags |= GIANTHELD;
 		error = lookup(ndp);
-		/*
-		 * The Giant lock should only change when
-		 * crossing mount points.
-		 */
-		if (crossmnt) {
-			exp->nes_vfslocked =
-			    (ndp->ni_cnd.cn_flags & GIANTHELD) != 0;
-			ndp->ni_cnd.cn_flags &= ~GIANTHELD;
-		}
 		if (error)
 			break;
 
@@ -2471,7 +2460,10 @@ nfsvno_fhtovp(struct mount *mp, fhandle_t *fhp, struct sockaddr *nam,
 
 	*credp = NULL;
 	exp->nes_numsecflavor = 0;
-	error = VFS_FHTOVP(mp, &fhp->fh_fid, vpp);
+	if (VFS_NEEDSGIANT(mp))
+		error = ESTALE;
+	else
+		error = VFS_FHTOVP(mp, &fhp->fh_fid, vpp);
 	if (error != 0)
 		/* Make sure the server replies ESTALE to the client. */
 		error = ESTALE;
@@ -2521,19 +2513,8 @@ nfsvno_pathconf(struct vnode *vp, int flag, register_t *retf,
  *	- get vp and export rights by calling nfsvno_fhtovp()
  *	- if cred->cr_uid == 0 or MNT_EXPORTANON set it to credanon
  *	  for AUTH_SYS
- * Also handle getting the Giant lock for the file system,
- * as required:
- * - if same mount point as *mpp
- *       do nothing
- *   else if *mpp == NULL
- *       if already locked
- *           leave it locked
- *       else
- *           call VFS_LOCK_GIANT()
- *   else
- *       if already locked
- *            unlock Giant
- *       call VFS_LOCK_GIANT()
+ *	- if mpp != NULL, return the mount point so that it can
+ *	  be used for vn_finished_write() by the caller
  */
 void
 nfsd_fhtovp(struct nfsrv_descript *nd, struct nfsrvfh *nfp, int lktype,
@@ -2549,27 +2530,14 @@ nfsd_fhtovp(struct nfsrv_descript *nd, struct nfsrvfh *nfp, int lktype,
 	 * Check for the special case of the nfsv4root_fh.
 	 */
 	mp = vfs_busyfs(&fhp->fh_fsid);
+	if (mpp != NULL)
+		*mpp = mp;
 	if (mp == NULL) {
 		*vpp = NULL;
 		nd->nd_repstat = ESTALE;
-		if (*mpp && exp->nes_vfslocked)
-			VFS_UNLOCK_GIANT(*mpp);
-		*mpp = NULL;
-		exp->nes_vfslocked = 0;
 		return;
 	}
 
-	/*
-	 * Now, handle Giant for the file system.
-	 */
-	if (*mpp != NULL && *mpp != mp && exp->nes_vfslocked) {
-		VFS_UNLOCK_GIANT(*mpp);
-		exp->nes_vfslocked = 0;
-	}
-	if (!exp->nes_vfslocked && *mpp != mp)
-		exp->nes_vfslocked = VFS_LOCK_GIANT(mp);
-
-	*mpp = mp;
 	if (startwrite)
 		vn_start_write(NULL, mpp, V_WAIT);
 
@@ -2633,12 +2601,9 @@ nfsd_fhtovp(struct nfsrv_descript *nd, struct nfsrvfh *nfp, int lktype,
 	if (nd->nd_repstat) {
 		if (startwrite)
 			vn_finished_write(mp);
-		if (exp->nes_vfslocked) {
-			VFS_UNLOCK_GIANT(mp);
-			exp->nes_vfslocked = 0;
-		}
 		*vpp = NULL;
-		*mpp = NULL;
+		if (mpp != NULL)
+			*mpp = NULL;
 	}
 }
 
@@ -2840,29 +2805,6 @@ nfsvno_advlock(struct vnode *vp, int ftype, u_int64_t first,
 }
 
 /*
- * Unlock an underlying local file system.
- */
-void
-nfsvno_unlockvfs(struct mount *mp)
-{
-
-	VFS_UNLOCK_GIANT(mp);
-}
-
-/*
- * Lock an underlying file system, as required, and return
- * whether or not it is locked.
- */
-int
-nfsvno_lockvfs(struct mount *mp)
-{
-	int ret;
-
-	ret = VFS_LOCK_GIANT(mp);
-	return (ret);
-}
-
-/*
  * Check the nfsv4 root exports.
  */
 int
diff --git a/sys/fs/nfsserver/nfs_nfsdserv.c b/sys/fs/nfsserver/nfs_nfsdserv.c
index f3eb52d..09a82b7 100644
--- a/sys/fs/nfsserver/nfs_nfsdserv.c
+++ b/sys/fs/nfsserver/nfs_nfsdserv.c
@@ -1351,7 +1351,6 @@ nfsrvd_rename(struct nfsrv_descript *nd, int isdgram,
 	struct nfsvattr fdirfor, fdiraft, tdirfor, tdiraft;
 	struct nfsexstuff tnes;
 	struct nfsrvfh tfh;
-	mount_t mp = NULL;
 	char *bufp, *tbufp = NULL;
 	u_long *hashp;
 
@@ -1387,9 +1386,7 @@ nfsrvd_rename(struct nfsrv_descript *nd, int isdgram,
 			return (error);
 		}
 		nd->nd_cred->cr_uid = nd->nd_saveduid;
-		/* Won't lock vfs if already locked, mp == NULL */
-		tnes.nes_vfslocked = exp->nes_vfslocked;
-		nfsd_fhtovp(nd, &tfh, LK_EXCLUSIVE, &tdp, &tnes, &mp, 0, p);
+		nfsd_fhtovp(nd, &tfh, LK_EXCLUSIVE, &tdp, &tnes, NULL, 0, p);
 		if (tdp) {
 			tdirfor_ret = nfsvno_getattr(tdp, &tdirfor, nd->nd_cred,
 			    p, 1);
@@ -1401,12 +1398,8 @@ nfsrvd_rename(struct nfsrv_descript *nd, int isdgram,
 	if (!nd->nd_repstat) {
 		error = nfsrv_parsename(nd, tbufp, hashp, &tond.ni_pathlen);
 		if (error) {
-			if (tdp) {
-				if (tnes.nes_vfslocked && !exp->nes_vfslocked &&
-				    !(nd->nd_flag & ND_NFSV4))
-					nfsvno_unlockvfs(mp);
+			if (tdp)
 				vrele(tdp);
-			}
 			vput(dp);
 			nfsvno_relpathbuf(&fromnd);
 			nfsvno_relpathbuf(&tond);
@@ -1420,12 +1413,8 @@ nfsrvd_rename(struct nfsrv_descript *nd, int isdgram,
 			nfsrv_wcc(nd, tdirfor_ret, &tdirfor, tdiraft_ret,
 			    &tdiraft);
 		}
-		if (tdp) {
-			if (tnes.nes_vfslocked && !exp->nes_vfslocked &&
-			    !(nd->nd_flag & ND_NFSV4))
-				nfsvno_unlockvfs(mp);
+		if (tdp)
 			vrele(tdp);
-		}
 		vput(dp);
 		nfsvno_relpathbuf(&fromnd);
 		nfsvno_relpathbuf(&tond);
@@ -1445,12 +1434,8 @@ nfsrvd_rename(struct nfsrv_descript *nd, int isdgram,
 		}
 		if (fdirp)
 			vrele(fdirp);
-		if (tdp) {
-			if (tnes.nes_vfslocked && !exp->nes_vfslocked &&
-			    !(nd->nd_flag & ND_NFSV4))
-				nfsvno_unlockvfs(mp);
+		if (tdp)
 			vrele(tdp);
-		}
 		nfsvno_relpathbuf(&tond);
 		return (0);
 	}
@@ -1465,9 +1450,6 @@ nfsrvd_rename(struct nfsrv_descript *nd, int isdgram,
 	if (tdirp)
 		tdiraft_ret = nfsvno_getattr(tdirp, &tdiraft, nd->nd_cred, p,
 		    0);
-	if (tnes.nes_vfslocked && !exp->nes_vfslocked &&
-	    !(nd->nd_flag & ND_NFSV4))
-		nfsvno_unlockvfs(mp);
 	if (fdirp)
 		vrele(fdirp);
 	if (tdirp)
@@ -1505,7 +1487,6 @@ nfsrvd_link(struct nfsrv_descript *nd, int isdgram,
 	struct nfsvattr dirfor, diraft, at;
 	struct nfsexstuff tnes;
 	struct nfsrvfh dfh;
-	mount_t mp = NULL;
 	char *bufp;
 	u_long *hashp;
 
@@ -1541,9 +1522,7 @@ nfsrvd_link(struct nfsrv_descript *nd, int isdgram,
 				/* tovp is always NULL unless NFSv4 */
 				return (error);
 			}
-			/* Won't lock vfs if already locked, mp == NULL */
-			tnes.nes_vfslocked = exp->nes_vfslocked;
-			nfsd_fhtovp(nd, &dfh, LK_EXCLUSIVE, &dp, &tnes, &mp, 0,
+			nfsd_fhtovp(nd, &dfh, LK_EXCLUSIVE, &dp, &tnes, NULL, 0,
 			    p);
 			if (dp)
 				NFSVOPUNLOCK(dp, 0, p);
@@ -1556,12 +1535,8 @@ nfsrvd_link(struct nfsrv_descript *nd, int isdgram,
 		error = nfsrv_parsename(nd, bufp, hashp, &named.ni_pathlen);
 		if (error) {
 			vrele(vp);
-			if (dp) {
-				if (tnes.nes_vfslocked && !exp->nes_vfslocked &&
-				    !(nd->nd_flag & ND_NFSV4))
-					nfsvno_unlockvfs(mp);
+			if (dp)
 				vrele(dp);
-			}
 			nfsvno_relpathbuf(&named);
 			return (error);
 		}
@@ -1591,9 +1566,6 @@ nfsrvd_link(struct nfsrv_descript *nd, int isdgram,
 		diraft_ret = nfsvno_getattr(dirp, &diraft, nd->nd_cred, p, 0);
 		vrele(dirp);
 	}
-	if (tnes.nes_vfslocked && !exp->nes_vfslocked &&
-	    !(nd->nd_flag & ND_NFSV4))
-		nfsvno_unlockvfs(mp);
 	vrele(vp);
 	if (nd->nd_flag & ND_NFSV3) {
 		nfsrv_postopattr(nd, getret, &at);
@@ -3101,7 +3073,6 @@ nfsrvd_secinfo(struct nfsrv_descript *nd, int isdgram,
 	vnode_t dirp = NULL, vp;
 	struct nfsrvfh fh;
 	struct nfsexstuff retnes;
-	mount_t mp;
 	u_int32_t *sizp;
 	int error, savflag, i;
 	char *bufp;
@@ -3134,12 +3105,10 @@ nfsrvd_secinfo(struct nfsrv_descript *nd, int isdgram,
 	fh.nfsrvfh_len = NFSX_MYFH;
 	vp = named.ni_vp;
 	nd->nd_repstat = nfsvno_getfh(vp, (fhandle_t *)fh.nfsrvfh_data, p);
-	mp = vnode_mount(vp);	/* so it won't try to re-lock filesys */
-	retnes.nes_vfslocked = exp->nes_vfslocked;
 	vput(vp);
 	savflag = nd->nd_flag;
 	if (!nd->nd_repstat) {
-		nfsd_fhtovp(nd, &fh, LK_SHARED, &vp, &retnes, &mp, 0, p);
+		nfsd_fhtovp(nd, &fh, LK_SHARED, &vp, &retnes, NULL, 0, p);
 		if (vp)
 			vput(vp);
 	}
diff --git a/sys/fs/nfsserver/nfs_nfsdsocket.c b/sys/fs/nfsserver/nfs_nfsdsocket.c
index ebee570..eeecded 100644
--- a/sys/fs/nfsserver/nfs_nfsdsocket.c
+++ b/sys/fs/nfsserver/nfs_nfsdsocket.c
@@ -386,7 +386,6 @@ nfsrvd_dorpc(struct nfsrv_descript *nd, int isdgram,
 				lktype = LK_SHARED;
 			else
 				lktype = LK_EXCLUSIVE;
-			nes.nes_vfslocked = 0;
 			if (nd->nd_flag & ND_PUBLOOKUP)
 				nfsd_fhtovp(nd, &nfs_pubfh, lktype, &vp, &nes,
 				    &mp, nfs_writerpc[nd->nd_procnum], p);
@@ -415,12 +414,8 @@ nfsrvd_dorpc(struct nfsrv_descript *nd, int isdgram,
 	if (nd->nd_repstat && (nd->nd_flag & ND_NFSV2)) {
 		*nd->nd_errp = nfsd_errmap(nd);
 		NFSINCRGLOBAL(newnfsstats.srvrpccnt[nfsv3to4op[nd->nd_procnum]]);
-		if (mp != NULL) {
-			if (nfs_writerpc[nd->nd_procnum])
-				NFS_ENDWRITE(mp);
-			if (nes.nes_vfslocked)
-				nfsvno_unlockvfs(mp);
-		}
+		if (mp != NULL && nfs_writerpc[nd->nd_procnum] != 0)
+			vn_finished_write(mp);
 		return;
 	}
 
@@ -445,12 +440,8 @@ nfsrvd_dorpc(struct nfsrv_descript *nd, int isdgram,
 			error = (*(nfsrv3_procs0[nd->nd_procnum]))(nd, isdgram,
 			    vp, p, &nes);
 		}
-		if (mp) {
-			if (nfs_writerpc[nd->nd_procnum])
-				NFS_ENDWRITE(mp);
-			if (nes.nes_vfslocked)
-				nfsvno_unlockvfs(mp);
-		}
+		if (mp != NULL && nfs_writerpc[nd->nd_procnum] != 0)
+			vn_finished_write(mp);
 		NFSINCRGLOBAL(newnfsstats.srvrpccnt[nfsv3to4op[nd->nd_procnum]]);
 	}
 	if (error) {
@@ -498,9 +489,10 @@ nfsrvd_compound(struct nfsrv_descript *nd, int isdgram,
 	u_char tag[NFSV4_SMALLSTR + 1], *tagstr;
 	vnode_t vp, nvp, savevp;
 	struct nfsrvfh fh;
-	mount_t mp, savemp, temp_mp = NULL;
+	mount_t new_mp, temp_mp = NULL;
 	struct ucred *credanon;
 	struct nfsexstuff nes, vpnes, savevpnes;
+	fsid_t cur_fsid, save_fsid;
 	static u_int64_t compref = 0;
 
 	NFSVNO_EXINIT(&vpnes);
@@ -597,8 +589,8 @@ nfsrvd_compound(struct nfsrv_descript *nd, int isdgram,
 	}
 
 	savevp = vp = NULL;
-	savevpnes.nes_vfslocked = vpnes.nes_vfslocked = 0;
-	savemp = mp = NULL;
+	save_fsid.val[0] = save_fsid.val[1] = 0;
+	cur_fsid.val[0] = cur_fsid.val[1] = 0;
 	NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
 	taglen = fxdr_unsigned(int, *tl);
 	if (taglen < 0) {
@@ -704,46 +696,44 @@ nfsrvd_compound(struct nfsrv_descript *nd, int isdgram,
 			error = nfsrv_mtofh(nd, &fh);
 			if (error)
 				goto nfsmout;
-			if (!nd->nd_repstat) {
-				nes.nes_vfslocked = vpnes.nes_vfslocked;
-				nfsd_fhtovp(nd, &fh, LK_SHARED, &nvp, &nes, &mp,
-				    0, p);
-			}
+			if (!nd->nd_repstat)
+				nfsd_fhtovp(nd, &fh, LK_SHARED, &nvp, &nes,
+				    NULL, 0, p);
 			/* For now, allow this for non-export FHs */
 			if (!nd->nd_repstat) {
 				if (vp)
 					vrele(vp);
 				vp = nvp;
-				NFSVOPUNLOCK(vp, 0, p);
+				cur_fsid = vp->v_mount->mnt_stat.f_fsid;
+				VOP_UNLOCK(vp, 0);
 				vpnes = nes;
 			}
 			break;
 		case NFSV4OP_PUTPUBFH:
-			if (nfs_pubfhset) {
-			    nes.nes_vfslocked = vpnes.nes_vfslocked;
+			if (nfs_pubfhset)
 			    nfsd_fhtovp(nd, &nfs_pubfh, LK_SHARED, &nvp,
-				&nes, &mp, 0, p);
-			} else {
+				&nes, NULL, 0, p);
+			else
 			    nd->nd_repstat = NFSERR_NOFILEHANDLE;
-			}
 			if (!nd->nd_repstat) {
 				if (vp)
 					vrele(vp);
 				vp = nvp;
-				NFSVOPUNLOCK(vp, 0, p);
+				cur_fsid = vp->v_mount->mnt_stat.f_fsid;
+				VOP_UNLOCK(vp, 0);
 				vpnes = nes;
 			}
 			break;
 		case NFSV4OP_PUTROOTFH:
 			if (nfs_rootfhset) {
-				nes.nes_vfslocked = vpnes.nes_vfslocked;
 				nfsd_fhtovp(nd, &nfs_rootfh, LK_SHARED, &nvp,
-				    &nes, &mp, 0, p);
+				    &nes, NULL, 0, p);
 				if (!nd->nd_repstat) {
 					if (vp)
 						vrele(vp);
 					vp = nvp;
-					NFSVOPUNLOCK(vp, 0, p);
+					cur_fsid = vp->v_mount->mnt_stat.f_fsid;
+					VOP_UNLOCK(vp, 0);
 					vpnes = nes;
 				}
 			} else
@@ -759,7 +749,7 @@ nfsrvd_compound(struct nfsrv_descript *nd, int isdgram,
 					VREF(vp);
 					savevp = vp;
 					savevpnes = vpnes;
-					savemp = mp;
+					save_fsid = cur_fsid;
 				}
 			} else {
 				nd->nd_repstat = NFSERR_NOFILEHANDLE;
@@ -771,23 +761,10 @@ nfsrvd_compound(struct nfsrv_descript *nd, int isdgram,
 				/* If vp == savevp, a no-op */
 				if (vp != savevp) {
 					VREF(savevp);
-					if (mp == NULL || savemp == NULL)
-						panic("nfscmpmp");
-					if (!savevpnes.nes_vfslocked &&
-					    vpnes.nes_vfslocked) {
-						if (mp == savemp)
-							panic("nfscmp2");
-						nfsvno_unlockvfs(mp);
-					} else if (savevpnes.nes_vfslocked &&
-					    !vpnes.nes_vfslocked) {
-						if (mp == savemp)
-							panic("nfscmp3");
-						savevpnes.nes_vfslocked = nfsvno_lockvfs(savemp);
-					}
 					vrele(vp);
 					vp = savevp;
 					vpnes = savevpnes;
-					mp = savemp;
+					cur_fsid = save_fsid;
 				}
 			} else {
 				nd->nd_repstat = NFSERR_RESTOREFH;
@@ -841,11 +818,14 @@ nfsrvd_compound(struct nfsrv_descript *nd, int isdgram,
 			error = (*(nfsrv4_ops1[op]))(nd, isdgram, vp,
 			    &nvp, (fhandle_t *)fh.nfsrvfh_data, p, &vpnes);
 			if (!error && !nd->nd_repstat) {
-			    if (vfs_statfs(mp)->f_fsid.val[0] !=
-				vfs_statfs(vnode_mount(nvp))->f_fsid.val[0] ||
-				vfs_statfs(mp)->f_fsid.val[1] !=
-				vfs_statfs(vnode_mount(nvp))->f_fsid.val[1]) {
-				    nd->nd_repstat = nfsvno_checkexp(vnode_mount(nvp),
+			    if (op == NFSV4OP_LOOKUP || op == NFSV4OP_LOOKUPP) {
+				new_mp = nvp->v_mount;
+				if (cur_fsid.val[0] !=
+				    new_mp->mnt_stat.f_fsid.val[0] ||
+				    cur_fsid.val[1] !=
+				    new_mp->mnt_stat.f_fsid.val[1]) {
+				    /* crossed a server mount point */
+				    nd->nd_repstat = nfsvno_checkexp(new_mp,
 					nd->nd_nam, &nes, &credanon);
 				    if (!nd->nd_repstat)
 					nd->nd_repstat = nfsd_excred(nd,
@@ -853,17 +833,13 @@ nfsrvd_compound(struct nfsrv_descript *nd, int isdgram,
 				    if (credanon != NULL)
 					crfree(credanon);
 				    if (!nd->nd_repstat) {
-					if (vpnes.nes_vfslocked)
-					    nfsvno_unlockvfs(mp);
-					mp = vnode_mount(nvp);
 					vpnes = nes;
-					vpnes.nes_vfslocked =
-					    nfsvno_lockvfs(mp);
+					cur_fsid = new_mp->mnt_stat.f_fsid;
 				    }
+				}
+				/* Lookup ops return a locked vnode */
+				VOP_UNLOCK(nvp, 0);
 			    }
-			    if (op == NFSV4OP_LOOKUP || op == NFSV4OP_LOOKUPP)
-				    /* Lookup ops return a locked vnode */
-				    VOP_UNLOCK(nvp, 0);
 			    if (!nd->nd_repstat) {
 				    vrele(vp);
 				    vp = nvp;
@@ -876,7 +852,8 @@ nfsrvd_compound(struct nfsrv_descript *nd, int isdgram,
 			if (vp == NULL || savevp == NULL) {
 				nd->nd_repstat = NFSERR_NOFILEHANDLE;
 				break;
-			} else if (mp != savemp) {
+			} else if (cur_fsid.val[0] != save_fsid.val[0] ||
+			    cur_fsid.val[1] != save_fsid.val[1]) {
 				nd->nd_repstat = NFSERR_XDEV;
 				break;
 			}
@@ -960,8 +937,6 @@ nfsmout:
 	} else {
 		*retopsp = txdr_unsigned(retops);
 	}
-	if (mp && vpnes.nes_vfslocked)
-		nfsvno_unlockvfs(mp);
 	if (vp)
 		vrele(vp);
 	if (savevp)