Author: kib Date: Tue Oct 22 16:17:38 2019 New Revision: 353891 URL: https://svnweb.freebsd.org/changeset/base/353891
Log: Fix interface between nfsclient and vnode pager. Make the nfsclient always call vnode_pager_setsize() with the vnode exclusively locked. This ensures that page fault always can find the backing page if the object size check succeeded. Set VV_VMSIZEVNLOCK flag on NFS nodes. The main offender breaking the interface in nfsclient is nfs_loadattrcache(), which is used whenever server responded with updated attributes, which can happen on non-changing operations as well. Also, iod threads only have buffers locked (and even that is LK_KERNPROC), but they still may call nfs_loadattrcache() on RPC response. Instead of immediately calling vnode_pager_setsize() if server response indicated changed file size, but the vnode is not exclusively locked, set a new node flag NVNSETSZSKIP. When the vnode exclusively locked, or when we can temporary upgrade the lock to exclusive, call vnode_pager_setsize(), by providing the nfsclient VOP_LOCK() implementation. Tested by: pho Discussed with: rmacklem Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Differential revision: https://reviews.freebsd.org/D21883 Modified: head/sys/fs/nfs/nfsport.h head/sys/fs/nfsclient/nfs_clnode.c head/sys/fs/nfsclient/nfs_clport.c head/sys/fs/nfsclient/nfs_clsubs.c head/sys/fs/nfsclient/nfs_clvnops.c head/sys/fs/nfsclient/nfsnode.h Modified: head/sys/fs/nfs/nfsport.h ============================================================================== --- head/sys/fs/nfs/nfsport.h Tue Oct 22 16:09:25 2019 (r353890) +++ head/sys/fs/nfs/nfsport.h Tue Oct 22 16:17:38 2019 (r353891) @@ -878,6 +878,7 @@ MALLOC_DECLARE(M_NEWNFSDSESSION); int nfscl_loadattrcache(struct vnode **, struct nfsvattr *, void *, void *, int, int); int newnfs_realign(struct mbuf **, int); +bool ncl_pager_setsize(struct vnode *vp, u_quad_t *nsizep); /* * If the port runs on an SMP box that can enforce Atomic ops with low Modified: head/sys/fs/nfsclient/nfs_clnode.c ============================================================================== --- head/sys/fs/nfsclient/nfs_clnode.c Tue Oct 22 16:09:25 2019 (r353890) +++ head/sys/fs/nfsclient/nfs_clnode.c Tue Oct 22 16:17:38 2019 (r353891) @@ -162,6 +162,8 @@ ncl_nget(struct mount *mntp, u_int8_t *fhp, int fhsize vp->v_type = VDIR; vp->v_vflag |= VV_ROOT; } + + vp->v_vflag |= VV_VMSIZEVNLOCK; np->n_fhp = malloc(sizeof (struct nfsfh) + fhsize, M_NFSFH, M_WAITOK); Modified: head/sys/fs/nfsclient/nfs_clport.c ============================================================================== --- head/sys/fs/nfsclient/nfs_clport.c Tue Oct 22 16:09:25 2019 (r353890) +++ head/sys/fs/nfsclient/nfs_clport.c Tue Oct 22 16:17:38 2019 (r353891) @@ -246,6 +246,8 @@ nfscl_nget(struct mount *mntp, struct vnode *dvp, stru vp->v_type = VDIR; vp->v_vflag |= VV_ROOT; } + + vp->v_vflag |= VV_VMSIZEVNLOCK; np->n_fhp = nfhp; /* @@ -414,10 +416,7 @@ nfscl_loadattrcache(struct vnode **vpp, struct nfsvatt struct nfsnode *np; struct nfsmount *nmp; struct timespec mtime_save; - vm_object_t object; - u_quad_t nsize; int error, force_fid_err; - bool setnsize; error = 0; @@ -565,27 +564,53 @@ out: if (np->n_attrstamp != 0) KDTRACE_NFS_ATTRCACHE_LOAD_DONE(vp, vap, error); #endif + (void)ncl_pager_setsize(vp, NULL); + return (error); +} + +/* + * Call vnode_pager_setsize() if the size of the node changed, as + * recorded in nfsnode vs. v_object, or delay the call if notifying + * the pager is not possible at the moment. + * + * If nsizep is non-NULL, the call is delayed and the new node size is + * provided. Caller should itself call vnode_pager_setsize() if + * function returned true. If nsizep is NULL, function tries to call + * vnode_pager_setsize() itself if needed and possible, and the nfs + * node is unlocked unconditionally, the return value is not useful. + */ +bool +ncl_pager_setsize(struct vnode *vp, u_quad_t *nsizep) +{ + struct nfsnode *np; + vm_object_t object; + struct vattr *vap; + u_quad_t nsize; + bool setnsize; + + np = VTONFS(vp); + NFSASSERTNODE(np); + + vap = &np->n_vattr.na_vattr; nsize = vap->va_size; object = vp->v_object; setnsize = false; - if (object != NULL) { - if (OFF_TO_IDX(nsize + PAGE_MASK) < object->size) { - /* - * When shrinking the size, the call to - * vnode_pager_setsize() cannot be done with - * the mutex held, because we might need to - * wait for a busy page. Delay it until after - * the node is unlocked. - */ + + if (object != NULL && nsize != object->un_pager.vnp.vnp_size) { + if (VOP_ISLOCKED(vp) == LK_EXCLUSIVE) setnsize = true; - } else { + else + np->n_flag |= NVNSETSZSKIP; + } + if (nsizep == NULL) { + NFSUNLOCKNODE(np); + if (setnsize) vnode_pager_setsize(vp, nsize); - } + setnsize = false; + } else { + *nsizep = nsize; } - NFSUNLOCKNODE(np); - if (setnsize) - vnode_pager_setsize(vp, nsize); - return (error); + return (setnsize); } /* Modified: head/sys/fs/nfsclient/nfs_clsubs.c ============================================================================== --- head/sys/fs/nfsclient/nfs_clsubs.c Tue Oct 22 16:09:25 2019 (r353890) +++ head/sys/fs/nfsclient/nfs_clsubs.c Tue Oct 22 16:17:38 2019 (r353891) @@ -185,6 +185,8 @@ ncl_getattrcache(struct vnode *vp, struct vattr *vaper struct vattr *vap; struct nfsmount *nmp; int timeo, mustflush; + u_quad_t nsize; + bool setnsize; np = VTONFS(vp); vap = &np->n_vattr.na_vattr; @@ -230,6 +232,7 @@ ncl_getattrcache(struct vnode *vp, struct vattr *vaper return( ENOENT); } nfsstatsv1.attrcache_hits++; + setnsize = false; if (vap->va_size != np->n_size) { if (vap->va_type == VREG) { if (np->n_flag & NMODIFIED) { @@ -240,7 +243,7 @@ ncl_getattrcache(struct vnode *vp, struct vattr *vaper } else { np->n_size = vap->va_size; } - vnode_pager_setsize(vp, np->n_size); + setnsize = ncl_pager_setsize(vp, &nsize); } else { np->n_size = vap->va_size; } @@ -253,6 +256,8 @@ ncl_getattrcache(struct vnode *vp, struct vattr *vaper vaper->va_mtime = np->n_mtim; } NFSUNLOCKNODE(np); + if (setnsize) + vnode_pager_setsize(vp, nsize); KDTRACE_NFS_ATTRCACHE_GET_HIT(vp, vap); return (0); } Modified: head/sys/fs/nfsclient/nfs_clvnops.c ============================================================================== --- head/sys/fs/nfsclient/nfs_clvnops.c Tue Oct 22 16:09:25 2019 (r353890) +++ head/sys/fs/nfsclient/nfs_clvnops.c Tue Oct 22 16:17:38 2019 (r353891) @@ -142,6 +142,7 @@ static vop_advlock_t nfs_advlock; static vop_advlockasync_t nfs_advlockasync; static vop_getacl_t nfs_getacl; static vop_setacl_t nfs_setacl; +static vop_lock1_t nfs_lock; /* * Global vfs data structures for nfs @@ -160,6 +161,7 @@ static struct vop_vector newnfs_vnodeops_nosig = { .vop_putpages = ncl_putpages, .vop_inactive = ncl_inactive, .vop_link = nfs_link, + .vop_lock1 = nfs_lock, .vop_lookup = nfs_lookup, .vop_mkdir = nfs_mkdir, .vop_mknod = nfs_mknod, @@ -294,6 +296,73 @@ SYSCTL_INT(_vfs_nfs, OID_AUTO, nfs_directio_allow_mmap rep->r_mtx * rep->r_mtx : Protects the fields in an nfsreq. */ + +static int +nfs_lock(struct vop_lock1_args *ap) +{ + struct vnode *vp; + struct nfsnode *np; + u_quad_t nsize; + int error, lktype; + bool onfault; + + vp = ap->a_vp; + lktype = ap->a_flags & LK_TYPE_MASK; + error = VOP_LOCK1_APV(&default_vnodeops, ap); + if (error != 0 || vp->v_op != &newnfs_vnodeops) + return (error); + np = VTONFS(vp); + NFSLOCKNODE(np); + if ((np->n_flag & NVNSETSZSKIP) == 0 || (lktype != LK_SHARED && + lktype != LK_EXCLUSIVE && lktype != LK_UPGRADE && + lktype != LK_TRYUPGRADE)) { + NFSUNLOCKNODE(np); + return (0); + } + onfault = (ap->a_flags & LK_EATTR_MASK) == LK_NOWAIT && + (ap->a_flags & LK_INIT_MASK) == LK_CANRECURSE && + (lktype == LK_SHARED || lktype == LK_EXCLUSIVE); + if (onfault && vp->v_vnlock->lk_recurse == 0) { + /* + * Force retry in vm_fault(), to make the lock request + * sleepable, which allows us to piggy-back the + * sleepable call to vnode_pager_setsize(). + */ + NFSUNLOCKNODE(np); + VOP_UNLOCK(vp, 0); + return (EBUSY); + } + if ((ap->a_flags & LK_NOWAIT) != 0 || + (lktype == LK_SHARED && vp->v_vnlock->lk_recurse > 0)) { + NFSUNLOCKNODE(np); + return (0); + } + if (lktype == LK_SHARED) { + NFSUNLOCKNODE(np); + VOP_UNLOCK(vp, 0); + ap->a_flags &= ~(LK_TYPE_MASK | LK_INTERLOCK); + ap->a_flags |= LK_EXCLUSIVE; + error = VOP_LOCK1_APV(&default_vnodeops, ap); + if (error != 0 || vp->v_op != &newnfs_vnodeops) + return (error); + NFSLOCKNODE(np); + if ((np->n_flag & NVNSETSZSKIP) == 0) { + NFSUNLOCKNODE(np); + goto downgrade; + } + } + np->n_flag &= ~NVNSETSZSKIP; + nsize = np->n_size; + NFSUNLOCKNODE(np); + vnode_pager_setsize(vp, nsize); +downgrade: + if (lktype == LK_SHARED) { + ap->a_flags &= ~(LK_TYPE_MASK | LK_INTERLOCK); + ap->a_flags |= LK_DOWNGRADE; + (void)VOP_LOCK1_APV(&default_vnodeops, ap); + } + return (0); +} static int nfs34_access_otw(struct vnode *vp, int wmode, struct thread *td, Modified: head/sys/fs/nfsclient/nfsnode.h ============================================================================== --- head/sys/fs/nfsclient/nfsnode.h Tue Oct 22 16:09:25 2019 (r353890) +++ head/sys/fs/nfsclient/nfsnode.h Tue Oct 22 16:17:38 2019 (r353891) @@ -163,6 +163,7 @@ struct nfsnode { #define NWRITEOPENED 0x00040000 /* Has been opened for writing */ #define NHASBEENLOCKED 0x00080000 /* Has been file locked. */ #define NDSCOMMIT 0x00100000 /* Commit is done via the DS. */ +#define NVNSETSZSKIP 0x00200000 /* Skipped vnode_pager_setsize() */ /* * Convert between nfsnode pointers and vnode pointers _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
