Push Giant a bit further off the NFS server in a number of straight
forward cases by converting from unconditional acquisition of Giant around vnode operations to conditional acquisition: - Remove nfsrv_access_withgiant(), and cause nfsrv_access() to now assert that Giant will be held if it is required for the vnode. - Add nfsrv_fhtovp_locked(), which will drop the NFS server lock if required, and modify nfsrv_fhtovp() to conditionally acquire Giant if required. - In the VOP's not dealing with more than one vnode at a time (i.e., not involving a lookup), conditionally acquire Giant. This removes Giant use for MPSAFE file systems for a number of quite important RPCs, including getattr, read, write. It leaves unconditional Giant acquisitions in vnode operations that interact with the name space or more than one vnode at a time as these require further work. Tested by: kris Reviewed by: kib
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parent
df19774d2f
commit
c2a9c542a9
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=164585
@ -360,6 +360,9 @@ int nfsrv_create(struct nfsrv_descript *nfsd, struct nfssvc_sock *slp,
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struct thread *td, struct mbuf **mrq);
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int nfsrv_fhtovp(fhandle_t *, int, struct vnode **, struct ucred *,
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struct nfssvc_sock *, struct sockaddr *, int *, int);
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int nfsrv_fhtovp_locked(fhandle_t *, int, struct vnode **,
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struct ucred *, struct nfssvc_sock *, struct sockaddr *, int *,
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int);
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int nfsrv_setpublicfs(struct mount *, struct netexport *,
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struct export_args *);
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int nfs_ispublicfh(fhandle_t *);
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File diff suppressed because it is too large
Load Diff
@ -624,7 +624,6 @@ nfs_namei(struct nameidata *ndp, fhandle_t *fhp, int len,
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NFSD_LOCK_ASSERT();
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NFSD_UNLOCK();
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mtx_lock(&Giant); /* VFS */
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*retdirp = NULL;
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cnp->cn_flags |= NOMACCHECK;
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@ -643,14 +642,14 @@ nfs_namei(struct nameidata *ndp, fhandle_t *fhp, int len,
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md = md->m_next;
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if (md == NULL) {
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error = EBADRPC;
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goto out;
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goto out_nogiant;
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}
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fromcp = mtod(md, caddr_t);
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rem = md->m_len;
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}
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if (*fromcp == '\0' || (!pubflag && *fromcp == '/')) {
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error = EACCES;
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goto out;
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goto out_nogiant;
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}
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*tocp++ = *fromcp++;
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rem--;
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@ -663,17 +662,17 @@ nfs_namei(struct nameidata *ndp, fhandle_t *fhp, int len,
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if (rem >= len)
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*dposp += len;
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else if ((error = nfs_adv(mdp, dposp, len, rem)) != 0)
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goto out;
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goto out_nogiant;
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}
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/*
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* Extract and set starting directory.
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*
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* XXXRW: For now, acquire Giant unconditionally to avoid tracking it
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* on multiple vnodes.
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*/
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mtx_unlock(&Giant); /* VFS */
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NFSD_LOCK();
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error = nfsrv_fhtovp(fhp, FALSE, &dp, ndp->ni_cnd.cn_cred, slp,
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nam, &rdonly, pubflag);
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NFSD_UNLOCK();
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mtx_lock(&Giant); /* VFS */
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if (error)
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goto out;
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@ -889,6 +888,8 @@ nfs_namei(struct nameidata *ndp, fhandle_t *fhp, int len,
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* cleanup state trivially.
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*/
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out:
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mtx_unlock(&Giant); /* VFS */
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out_nogiant:
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if (error) {
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uma_zfree(namei_zone, cnp->cn_pnbuf);
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ndp->ni_vp = NULL;
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@ -898,7 +899,6 @@ nfs_namei(struct nameidata *ndp, fhandle_t *fhp, int len,
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} else if ((ndp->ni_cnd.cn_flags & (WANTPARENT|LOCKPARENT)) == 0) {
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ndp->ni_dvp = NULL;
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}
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mtx_unlock(&Giant); /* VFS */
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NFSD_LOCK();
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return (error);
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}
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@ -1064,6 +1064,10 @@ nfsm_srvfattr(struct nfsrv_descript *nfsd, struct vattr *vap,
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* - get vp and export rights by calling VFS_FHTOVP()
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* - if cred->cr_uid == 0 or MNT_EXPORTANON set it to credanon
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* - if not lockflag unlock it with VOP_UNLOCK()
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*
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* As this routine may acquire Giant and may sleep, it can't be called with
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* nfsd_mtx. Caller should invoke nfsrv_fhtovp_locked() if the lock is held
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* so that it can be automatically dropped and re-acquired.
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*/
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int
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nfsrv_fhtovp(fhandle_t *fhp, int lockflag, struct vnode **vpp,
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@ -1080,7 +1084,7 @@ nfsrv_fhtovp(fhandle_t *fhp, int lockflag, struct vnode **vpp,
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struct sockaddr_int *saddr;
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#endif
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NFSD_LOCK_ASSERT();
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NFSD_UNLOCK_ASSERT();
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*vpp = NULL;
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@ -1093,7 +1097,6 @@ nfsrv_fhtovp(fhandle_t *fhp, int lockflag, struct vnode **vpp,
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mp = vfs_getvfs(&fhp->fh_fsid);
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if (!mp)
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return (ESTALE);
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NFSD_UNLOCK();
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vfslocked = VFS_LOCK_GIANT(mp);
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error = VFS_CHECKEXP(mp, nam, &exflags, &credanon);
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if (error)
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@ -1133,10 +1136,27 @@ nfsrv_fhtovp(fhandle_t *fhp, int lockflag, struct vnode **vpp,
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out:
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vfs_rel(mp);
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VFS_UNLOCK_GIANT(vfslocked);
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NFSD_LOCK();
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return (error);
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}
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/*
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* Version of nfsrv_fhtovp() that can be called holding nfsd_mtx: it will
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* drop and re-acquire the lock for the caller.
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*/
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int
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nfsrv_fhtovp_locked(fhandle_t *fhp, int lockflag, struct vnode **vpp,
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struct ucred *cred, struct nfssvc_sock *slp, struct sockaddr *nam,
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int *rdonlyp, int pubflag)
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{
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int error;
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NFSD_LOCK_ASSERT();
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NFSD_UNLOCK();
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error = nfsrv_fhtovp(fhp, lockflag, vpp, cred, slp, nam, rdonlyp,
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pubflag);
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NFSD_LOCK();
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return (error);
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}
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/*
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* WebNFS: check if a filehandle is a public filehandle. For v3, this
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