Date: Mon, 24 Dec 2012 13:14:39 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-9@freebsd.org Subject: svn commit: r244654 - stable/9/sys/fs/nullfs Message-ID: <201212241314.qBODEdqL011389@svn.freebsd.org>
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Author: kib Date: Mon Dec 24 13:14:38 2012 New Revision: 244654 URL: http://svnweb.freebsd.org/changeset/base/244654 Log: MFC r240285: Allow shared lookups for nullfs mounts, if lower filesystem supports it. MFC r241548: Replace the XXX comment with the proper description. MFC r241554: Grammar fixes. Modified: stable/9/sys/fs/nullfs/null.h stable/9/sys/fs/nullfs/null_subr.c stable/9/sys/fs/nullfs/null_vfsops.c stable/9/sys/fs/nullfs/null_vnops.c Directory Properties: stable/9/sys/ (props changed) stable/9/sys/fs/ (props changed) Modified: stable/9/sys/fs/nullfs/null.h ============================================================================== --- stable/9/sys/fs/nullfs/null.h Mon Dec 24 13:05:27 2012 (r244653) +++ stable/9/sys/fs/nullfs/null.h Mon Dec 24 13:14:38 2012 (r244654) @@ -56,6 +56,7 @@ struct null_node { int nullfs_init(struct vfsconf *vfsp); int nullfs_uninit(struct vfsconf *vfsp); int null_nodeget(struct mount *mp, struct vnode *target, struct vnode **vpp); +struct vnode *null_hashget(struct mount *mp, struct vnode *lowervp); void null_hashrem(struct null_node *xp); int null_bypass(struct vop_generic_args *ap); Modified: stable/9/sys/fs/nullfs/null_subr.c ============================================================================== --- stable/9/sys/fs/nullfs/null_subr.c Mon Dec 24 13:05:27 2012 (r244653) +++ stable/9/sys/fs/nullfs/null_subr.c Mon Dec 24 13:14:38 2012 (r244654) @@ -67,7 +67,6 @@ struct mtx null_hashmtx; static MALLOC_DEFINE(M_NULLFSHASH, "nullfs_hash", "NULLFS hash table"); MALLOC_DEFINE(M_NULLFSNODE, "nullfs_node", "NULLFS vnode private part"); -static struct vnode * null_hashget(struct mount *, struct vnode *); static struct vnode * null_hashins(struct mount *, struct null_node *); /* @@ -98,7 +97,7 @@ nullfs_uninit(vfsp) * Return a VREF'ed alias for lower vnode if already exists, else 0. * Lower vnode should be locked on entry and will be left locked on exit. */ -static struct vnode * +struct vnode * null_hashget(mp, lowervp) struct mount *mp; struct vnode *lowervp; @@ -209,14 +208,10 @@ null_nodeget(mp, lowervp, vpp) struct vnode *vp; int error; - /* - * The insmntque1() call below requires the exclusive lock on - * the nullfs vnode. - */ - ASSERT_VOP_ELOCKED(lowervp, "lowervp"); - KASSERT(lowervp->v_usecount >= 1, ("Unreferenced vnode %p\n", lowervp)); + ASSERT_VOP_LOCKED(lowervp, "lowervp"); + KASSERT(lowervp->v_usecount >= 1, ("Unreferenced vnode %p", lowervp)); - /* Lookup the hash firstly */ + /* Lookup the hash firstly. */ *vpp = null_hashget(mp, lowervp); if (*vpp != NULL) { vrele(lowervp); @@ -224,6 +219,19 @@ null_nodeget(mp, lowervp, vpp) } /* + * The insmntque1() call below requires the exclusive lock on + * the nullfs vnode. Upgrade the lock now if hash failed to + * provide ready to use vnode. + */ + if (VOP_ISLOCKED(lowervp) != LK_EXCLUSIVE) { + vn_lock(lowervp, LK_UPGRADE | LK_RETRY); + if ((lowervp->v_iflag & VI_DOOMED) != 0) { + vput(lowervp); + return (ENOENT); + } + } + + /* * We do not serialize vnode creation, instead we will check for * duplicates later, when adding new vnode to hash. * Note that duplicate can only appear in hash if the lowervp is @@ -233,8 +241,7 @@ null_nodeget(mp, lowervp, vpp) * might cause a bogus v_data pointer to get dereferenced * elsewhere if MALLOC should block. */ - xp = malloc(sizeof(struct null_node), - M_NULLFSNODE, M_WAITOK); + xp = malloc(sizeof(struct null_node), M_NULLFSNODE, M_WAITOK); error = getnewvnode("null", mp, &null_vnodeops, &vp); if (error) { Modified: stable/9/sys/fs/nullfs/null_vfsops.c ============================================================================== --- stable/9/sys/fs/nullfs/null_vfsops.c Mon Dec 24 13:05:27 2012 (r244653) +++ stable/9/sys/fs/nullfs/null_vfsops.c Mon Dec 24 13:14:38 2012 (r244654) @@ -65,6 +65,7 @@ static vfs_statfs_t nullfs_statfs; static vfs_unmount_t nullfs_unmount; static vfs_vget_t nullfs_vget; static vfs_extattrctl_t nullfs_extattrctl; +static vfs_reclaim_lowervp_t nullfs_reclaim_lowervp; /* * Mount null layer @@ -121,8 +122,10 @@ nullfs_mount(struct mount *mp) */ NDINIT(ndp, LOOKUP, FOLLOW|LOCKLEAF, UIO_SYSSPACE, target, curthread); error = namei(ndp); + /* * Re-lock vnode. + * XXXKIB This is deadlock-prone as well. */ if (isvnunlocked) vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY); @@ -146,7 +149,7 @@ nullfs_mount(struct mount *mp) } xmp = (struct null_mount *) malloc(sizeof(struct null_mount), - M_NULLFSMNT, M_WAITOK); /* XXX */ + M_NULLFSMNT, M_WAITOK); /* * Save reference to underlying FS @@ -186,10 +189,15 @@ nullfs_mount(struct mount *mp) } MNT_ILOCK(mp); mp->mnt_kern_flag |= lowerrootvp->v_mount->mnt_kern_flag & - (MNTK_MPSAFE | MNTK_SHARED_WRITES); + (MNTK_MPSAFE | MNTK_SHARED_WRITES | MNTK_LOOKUP_SHARED | + MNTK_EXTENDED_SHARED); + mp->mnt_kern_flag |= MNTK_LOOKUP_EXCL_DOTDOT; MNT_IUNLOCK(mp); mp->mnt_data = xmp; vfs_getnewfsid(mp); + MNT_ILOCK(xmp->nullm_vfs); + TAILQ_INSERT_TAIL(&xmp->nullm_vfs->mnt_uppers, mp, mnt_upper_link); + MNT_IUNLOCK(xmp->nullm_vfs); vfs_mountedfrom(mp, target); @@ -206,14 +214,16 @@ nullfs_unmount(mp, mntflags) struct mount *mp; int mntflags; { - void *mntdata; - int error; - int flags = 0; + struct null_mount *mntdata; + struct mount *ump; + int error, flags; NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); if (mntflags & MNT_FORCE) - flags |= FORCECLOSE; + flags = FORCECLOSE; + else + flags = 0; /* There is 1 extra root vnode reference (nullm_rootvp). */ error = vflush(mp, 1, flags, curthread); @@ -224,9 +234,17 @@ nullfs_unmount(mp, mntflags) * Finally, throw away the null_mount structure */ mntdata = mp->mnt_data; - mp->mnt_data = 0; + ump = mntdata->nullm_vfs; + MNT_ILOCK(ump); + while ((ump->mnt_kern_flag & MNTK_VGONE_UPPER) != 0) { + ump->mnt_kern_flag |= MNTK_VGONE_WAITER; + msleep(&ump->mnt_uppers, &ump->mnt_mtx, 0, "vgnupw", 0); + } + TAILQ_REMOVE(&ump->mnt_uppers, mp, mnt_upper_link); + MNT_IUNLOCK(ump); + mp->mnt_data = NULL; free(mntdata, M_NULLFSMNT); - return 0; + return (0); } static int @@ -316,13 +334,10 @@ nullfs_vget(mp, ino, flags, vpp) KASSERT((flags & LK_TYPE_MASK) != 0, ("nullfs_vget: no lock requested")); - flags &= ~LK_TYPE_MASK; - flags |= LK_EXCLUSIVE; error = VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, flags, vpp); - if (error) + if (error != 0) return (error); - return (null_nodeget(mp, *vpp, vpp)); } @@ -334,11 +349,11 @@ nullfs_fhtovp(mp, fidp, flags, vpp) struct vnode **vpp; { int error; - error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, LK_EXCLUSIVE, + + error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, flags, vpp); - if (error) + if (error != 0) return (error); - return (null_nodeget(mp, *vpp, vpp)); } @@ -350,10 +365,22 @@ nullfs_extattrctl(mp, cmd, filename_vp, int namespace; const char *attrname; { - return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, filename_vp, - namespace, attrname); + + return (VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, + filename_vp, namespace, attrname)); } +static void +nullfs_reclaim_lowervp(struct mount *mp, struct vnode *lowervp) +{ + struct vnode *vp; + + vp = null_hashget(mp, lowervp); + if (vp == NULL) + return; + vgone(vp); + vn_lock(lowervp, LK_EXCLUSIVE | LK_RETRY); +} static struct vfsops null_vfsops = { .vfs_extattrctl = nullfs_extattrctl, @@ -367,6 +394,7 @@ static struct vfsops null_vfsops = { .vfs_uninit = nullfs_uninit, .vfs_unmount = nullfs_unmount, .vfs_vget = nullfs_vget, + .vfs_reclaim_lowervp = nullfs_reclaim_lowervp, }; VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK | VFCF_JAIL); Modified: stable/9/sys/fs/nullfs/null_vnops.c ============================================================================== --- stable/9/sys/fs/nullfs/null_vnops.c Mon Dec 24 13:05:27 2012 (r244653) +++ stable/9/sys/fs/nullfs/null_vnops.c Mon Dec 24 13:14:38 2012 (r244654) @@ -665,34 +665,20 @@ null_unlock(struct vop_unlock_args *ap) } /* - * There is no way to tell that someone issued remove/rmdir operation - * on the underlying filesystem. For now we just have to release lowervp - * as soon as possible. - * - * Note, we can't release any resources nor remove vnode from hash before - * appropriate VXLOCK stuff is done because other process can find this - * vnode in hash during inactivation and may be sitting in vget() and waiting - * for null_inactive to unlock vnode. Thus we will do all those in VOP_RECLAIM. + * Do not allow the VOP_INACTIVE to be passed to the lower layer, + * since the reference count on the lower vnode is not related to + * ours. */ static int -null_inactive(struct vop_inactive_args *ap) +null_inactive(struct vop_inactive_args *ap __unused) { - struct vnode *vp = ap->a_vp; - struct thread *td = ap->a_td; - - vp->v_object = NULL; - - /* - * If this is the last reference, then free up the vnode - * so as not to tie up the lower vnodes. - */ - vrecycle(vp, td); return (0); } /* - * Now, the VXLOCK is in force and we're free to destroy the null vnode. + * Now, the nullfs vnode and, due to the sharing lock, the lower + * vnode, are exclusively locked, and we shall destroy the null vnode. */ static int null_reclaim(struct vop_reclaim_args *ap)
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