Current Path : /sys/fs/nullfs/ |
FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
Current File : //sys/fs/nullfs/null_vfsops.c |
/*- * Copyright (c) 1992, 1993, 1995 * The Regents of the University of California. All rights reserved. * * This code is derived from software donated to Berkeley by * Jan-Simon Pendry. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)null_vfsops.c 8.2 (Berkeley) 1/21/94 * * @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92 * $FreeBSD: release/9.1.0/sys/fs/nullfs/null_vfsops.c 232728 2012-03-09 16:17:46Z mm $ */ /* * Null Layer * (See null_vnops.c for a description of what this does.) */ #include <sys/param.h> #include <sys/systm.h> #include <sys/fcntl.h> #include <sys/kernel.h> #include <sys/lock.h> #include <sys/malloc.h> #include <sys/mount.h> #include <sys/namei.h> #include <sys/proc.h> #include <sys/vnode.h> #include <sys/jail.h> #include <fs/nullfs/null.h> static MALLOC_DEFINE(M_NULLFSMNT, "nullfs_mount", "NULLFS mount structure"); static vfs_fhtovp_t nullfs_fhtovp; static vfs_mount_t nullfs_mount; static vfs_quotactl_t nullfs_quotactl; static vfs_root_t nullfs_root; static vfs_sync_t nullfs_sync; static vfs_statfs_t nullfs_statfs; static vfs_unmount_t nullfs_unmount; static vfs_vget_t nullfs_vget; static vfs_extattrctl_t nullfs_extattrctl; /* * Mount null layer */ static int nullfs_mount(struct mount *mp) { int error = 0; struct vnode *lowerrootvp, *vp; struct vnode *nullm_rootvp; struct null_mount *xmp; struct thread *td = curthread; char *target; int isvnunlocked = 0, len; struct nameidata nd, *ndp = &nd; NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp); if (!prison_allow(td->td_ucred, PR_ALLOW_MOUNT_NULLFS)) return (EPERM); if (mp->mnt_flag & MNT_ROOTFS) return (EOPNOTSUPP); /* * Update is a no-op */ if (mp->mnt_flag & MNT_UPDATE) { /* * Only support update mounts for NFS export. */ if (vfs_flagopt(mp->mnt_optnew, "export", NULL, 0)) return (0); else return (EOPNOTSUPP); } /* * Get argument */ error = vfs_getopt(mp->mnt_optnew, "target", (void **)&target, &len); if (error || target[len - 1] != '\0') return (EINVAL); /* * Unlock lower node to avoid possible deadlock. */ if ((mp->mnt_vnodecovered->v_op == &null_vnodeops) && VOP_ISLOCKED(mp->mnt_vnodecovered) == LK_EXCLUSIVE) { VOP_UNLOCK(mp->mnt_vnodecovered, 0); isvnunlocked = 1; } /* * Find lower node */ NDINIT(ndp, LOOKUP, FOLLOW|LOCKLEAF, UIO_SYSSPACE, target, curthread); error = namei(ndp); /* * Re-lock vnode. */ if (isvnunlocked) vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY); if (error) return (error); NDFREE(ndp, NDF_ONLY_PNBUF); /* * Sanity check on lower vnode */ lowerrootvp = ndp->ni_vp; /* * Check multi null mount to avoid `lock against myself' panic. */ if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) { NULLFSDEBUG("nullfs_mount: multi null mount?\n"); vput(lowerrootvp); return (EDEADLK); } xmp = (struct null_mount *) malloc(sizeof(struct null_mount), M_NULLFSMNT, M_WAITOK); /* XXX */ /* * Save reference to underlying FS */ xmp->nullm_vfs = lowerrootvp->v_mount; /* * Save reference. Each mount also holds * a reference on the root vnode. */ error = null_nodeget(mp, lowerrootvp, &vp); /* * Make sure the node alias worked */ if (error) { free(xmp, M_NULLFSMNT); return (error); } /* * Keep a held reference to the root vnode. * It is vrele'd in nullfs_unmount. */ nullm_rootvp = vp; nullm_rootvp->v_vflag |= VV_ROOT; xmp->nullm_rootvp = nullm_rootvp; /* * Unlock the node (either the lower or the alias) */ VOP_UNLOCK(vp, 0); if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) { MNT_ILOCK(mp); mp->mnt_flag |= MNT_LOCAL; MNT_IUNLOCK(mp); } MNT_ILOCK(mp); mp->mnt_kern_flag |= lowerrootvp->v_mount->mnt_kern_flag & (MNTK_MPSAFE | MNTK_SHARED_WRITES); MNT_IUNLOCK(mp); mp->mnt_data = xmp; vfs_getnewfsid(mp); vfs_mountedfrom(mp, target); NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n", mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); return (0); } /* * Free reference to null layer */ static int nullfs_unmount(mp, mntflags) struct mount *mp; int mntflags; { void *mntdata; int error; int flags = 0; NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); if (mntflags & MNT_FORCE) flags |= FORCECLOSE; /* There is 1 extra root vnode reference (nullm_rootvp). */ error = vflush(mp, 1, flags, curthread); if (error) return (error); /* * Finally, throw away the null_mount structure */ mntdata = mp->mnt_data; mp->mnt_data = 0; free(mntdata, M_NULLFSMNT); return 0; } static int nullfs_root(mp, flags, vpp) struct mount *mp; int flags; struct vnode **vpp; { struct vnode *vp; NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); /* * Return locked reference to root. */ vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; VREF(vp); ASSERT_VOP_UNLOCKED(vp, "root vnode is locked"); vn_lock(vp, flags | LK_RETRY); *vpp = vp; return 0; } static int nullfs_quotactl(mp, cmd, uid, arg) struct mount *mp; int cmd; uid_t uid; void *arg; { return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg); } static int nullfs_statfs(mp, sbp) struct mount *mp; struct statfs *sbp; { int error; struct statfs mstat; NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); bzero(&mstat, sizeof(mstat)); error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat); if (error) return (error); /* now copy across the "interesting" information and fake the rest */ sbp->f_type = mstat.f_type; sbp->f_flags = mstat.f_flags; sbp->f_bsize = mstat.f_bsize; sbp->f_iosize = mstat.f_iosize; sbp->f_blocks = mstat.f_blocks; sbp->f_bfree = mstat.f_bfree; sbp->f_bavail = mstat.f_bavail; sbp->f_files = mstat.f_files; sbp->f_ffree = mstat.f_ffree; return (0); } static int nullfs_sync(mp, waitfor) struct mount *mp; int waitfor; { /* * XXX - Assumes no data cached at null layer. */ return (0); } static int nullfs_vget(mp, ino, flags, vpp) struct mount *mp; ino_t ino; int flags; struct vnode **vpp; { int error; 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) return (error); return (null_nodeget(mp, *vpp, vpp)); } static int nullfs_fhtovp(mp, fidp, flags, vpp) struct mount *mp; struct fid *fidp; int flags; struct vnode **vpp; { int error; error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, LK_EXCLUSIVE, vpp); if (error) return (error); return (null_nodeget(mp, *vpp, vpp)); } static int nullfs_extattrctl(mp, cmd, filename_vp, namespace, attrname) struct mount *mp; int cmd; struct vnode *filename_vp; int namespace; const char *attrname; { return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, filename_vp, namespace, attrname); } static struct vfsops null_vfsops = { .vfs_extattrctl = nullfs_extattrctl, .vfs_fhtovp = nullfs_fhtovp, .vfs_init = nullfs_init, .vfs_mount = nullfs_mount, .vfs_quotactl = nullfs_quotactl, .vfs_root = nullfs_root, .vfs_statfs = nullfs_statfs, .vfs_sync = nullfs_sync, .vfs_uninit = nullfs_uninit, .vfs_unmount = nullfs_unmount, .vfs_vget = nullfs_vget, }; VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK | VFCF_JAIL);