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32 * @(#)null_vfsops.c 8.2 (Berkeley) 1/21/94
34 * @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92
40 * (See null_vnops.c for a description of what this does.)
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/fcntl.h>
46 #include <sys/kernel.h>
48 #include <sys/malloc.h>
49 #include <sys/mount.h>
50 #include <sys/namei.h>
52 #include <sys/vnode.h>
55 #include <fs/nullfs/null.h>
57 static MALLOC_DEFINE(M_NULLFSMNT, "nullfs_mount", "NULLFS mount structure");
59 static vfs_fhtovp_t nullfs_fhtovp;
60 static vfs_mount_t nullfs_mount;
61 static vfs_quotactl_t nullfs_quotactl;
62 static vfs_root_t nullfs_root;
63 static vfs_sync_t nullfs_sync;
64 static vfs_statfs_t nullfs_statfs;
65 static vfs_unmount_t nullfs_unmount;
66 static vfs_vget_t nullfs_vget;
67 static vfs_extattrctl_t nullfs_extattrctl;
73 nullfs_mount(struct mount *mp)
76 struct vnode *lowerrootvp, *vp;
77 struct vnode *nullm_rootvp;
78 struct null_mount *xmp;
79 struct thread *td = curthread;
81 int isvnunlocked = 0, len;
82 struct nameidata nd, *ndp = &nd;
84 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp);
86 if (!prison_allow(td->td_ucred, PR_ALLOW_MOUNT_NULLFS))
89 if (mp->mnt_flag & MNT_ROOTFS)
94 if (mp->mnt_flag & MNT_UPDATE) {
96 * Only support update mounts for NFS export.
98 if (vfs_flagopt(mp->mnt_optnew, "export", NULL, 0))
107 error = vfs_getopt(mp->mnt_optnew, "target", (void **)&target, &len);
108 if (error || target[len - 1] != '\0')
112 * Unlock lower node to avoid possible deadlock.
114 if ((mp->mnt_vnodecovered->v_op == &null_vnodeops) &&
115 VOP_ISLOCKED(mp->mnt_vnodecovered) == LK_EXCLUSIVE) {
116 VOP_UNLOCK(mp->mnt_vnodecovered, 0);
122 NDINIT(ndp, LOOKUP, FOLLOW|LOCKLEAF, UIO_SYSSPACE, target, curthread);
128 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY);
132 NDFREE(ndp, NDF_ONLY_PNBUF);
135 * Sanity check on lower vnode
137 lowerrootvp = ndp->ni_vp;
140 * Check multi null mount to avoid `lock against myself' panic.
142 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) {
143 NULLFSDEBUG("nullfs_mount: multi null mount?\n");
148 xmp = (struct null_mount *) malloc(sizeof(struct null_mount),
149 M_NULLFSMNT, M_WAITOK); /* XXX */
152 * Save reference to underlying FS
154 xmp->nullm_vfs = lowerrootvp->v_mount;
157 * Save reference. Each mount also holds
158 * a reference on the root vnode.
160 error = null_nodeget(mp, lowerrootvp, &vp);
162 * Make sure the node alias worked
165 free(xmp, M_NULLFSMNT);
170 * Keep a held reference to the root vnode.
171 * It is vrele'd in nullfs_unmount.
174 nullm_rootvp->v_vflag |= VV_ROOT;
175 xmp->nullm_rootvp = nullm_rootvp;
178 * Unlock the node (either the lower or the alias)
182 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) {
184 mp->mnt_flag |= MNT_LOCAL;
188 mp->mnt_kern_flag |= lowerrootvp->v_mount->mnt_kern_flag &
189 (MNTK_MPSAFE | MNTK_SHARED_WRITES);
194 vfs_mountedfrom(mp, target);
196 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n",
197 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
202 * Free reference to null layer
205 nullfs_unmount(mp, mntflags)
213 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp);
215 if (mntflags & MNT_FORCE)
218 /* There is 1 extra root vnode reference (nullm_rootvp). */
219 error = vflush(mp, 1, flags, curthread);
224 * Finally, throw away the null_mount structure
226 mntdata = mp->mnt_data;
228 free(mntdata, M_NULLFSMNT);
233 nullfs_root(mp, flags, vpp)
240 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp,
241 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
242 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
245 * Return locked reference to root.
247 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
250 ASSERT_VOP_UNLOCKED(vp, "root vnode is locked");
251 vn_lock(vp, flags | LK_RETRY);
257 nullfs_quotactl(mp, cmd, uid, arg)
263 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg);
267 nullfs_statfs(mp, sbp)
274 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp,
275 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
276 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
278 bzero(&mstat, sizeof(mstat));
280 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat);
284 /* now copy across the "interesting" information and fake the rest */
285 sbp->f_type = mstat.f_type;
286 sbp->f_flags = mstat.f_flags;
287 sbp->f_bsize = mstat.f_bsize;
288 sbp->f_iosize = mstat.f_iosize;
289 sbp->f_blocks = mstat.f_blocks;
290 sbp->f_bfree = mstat.f_bfree;
291 sbp->f_bavail = mstat.f_bavail;
292 sbp->f_files = mstat.f_files;
293 sbp->f_ffree = mstat.f_ffree;
298 nullfs_sync(mp, waitfor)
303 * XXX - Assumes no data cached at null layer.
309 nullfs_vget(mp, ino, flags, vpp)
317 KASSERT((flags & LK_TYPE_MASK) != 0,
318 ("nullfs_vget: no lock requested"));
319 flags &= ~LK_TYPE_MASK;
320 flags |= LK_EXCLUSIVE;
322 error = VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, flags, vpp);
326 return (null_nodeget(mp, *vpp, vpp));
330 nullfs_fhtovp(mp, fidp, flags, vpp)
337 error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, LK_EXCLUSIVE,
342 return (null_nodeget(mp, *vpp, vpp));
346 nullfs_extattrctl(mp, cmd, filename_vp, namespace, attrname)
349 struct vnode *filename_vp;
351 const char *attrname;
353 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, filename_vp,
354 namespace, attrname);
358 static struct vfsops null_vfsops = {
359 .vfs_extattrctl = nullfs_extattrctl,
360 .vfs_fhtovp = nullfs_fhtovp,
361 .vfs_init = nullfs_init,
362 .vfs_mount = nullfs_mount,
363 .vfs_quotactl = nullfs_quotactl,
364 .vfs_root = nullfs_root,
365 .vfs_statfs = nullfs_statfs,
366 .vfs_sync = nullfs_sync,
367 .vfs_uninit = nullfs_uninit,
368 .vfs_unmount = nullfs_unmount,
369 .vfs_vget = nullfs_vget,
372 VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK | VFCF_JAIL);