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34 * @(#)null_vfsops.c 8.2 (Berkeley) 1/21/94
36 * @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92
42 * (See null_vnops.c for a description of what this does.)
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/fcntl.h>
48 #include <sys/kernel.h>
50 #include <sys/malloc.h>
51 #include <sys/mount.h>
52 #include <sys/namei.h>
54 #include <sys/vnode.h>
57 #include <fs/nullfs/null.h>
59 static MALLOC_DEFINE(M_NULLFSMNT, "nullfs_mount", "NULLFS mount structure");
61 static vfs_fhtovp_t nullfs_fhtovp;
62 static vfs_mount_t nullfs_mount;
63 static vfs_quotactl_t nullfs_quotactl;
64 static vfs_root_t nullfs_root;
65 static vfs_sync_t nullfs_sync;
66 static vfs_statfs_t nullfs_statfs;
67 static vfs_unmount_t nullfs_unmount;
68 static vfs_vget_t nullfs_vget;
69 static vfs_extattrctl_t nullfs_extattrctl;
75 nullfs_mount(struct mount *mp)
78 struct vnode *lowerrootvp, *vp;
79 struct vnode *nullm_rootvp;
80 struct null_mount *xmp;
81 struct thread *td = curthread;
83 int isvnunlocked = 0, len;
84 struct nameidata nd, *ndp = &nd;
86 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp);
88 if (!prison_allow(td->td_ucred, PR_ALLOW_MOUNT_NULLFS))
90 if (mp->mnt_flag & MNT_ROOTFS)
96 if (mp->mnt_flag & MNT_UPDATE) {
98 * Only support update mounts for NFS export.
100 if (vfs_flagopt(mp->mnt_optnew, "export", NULL, 0))
109 error = vfs_getopt(mp->mnt_optnew, "target", (void **)&target, &len);
110 if (error || target[len - 1] != '\0')
114 * Unlock lower node to avoid possible deadlock.
116 if ((mp->mnt_vnodecovered->v_op == &null_vnodeops) &&
117 VOP_ISLOCKED(mp->mnt_vnodecovered) == LK_EXCLUSIVE) {
118 VOP_UNLOCK(mp->mnt_vnodecovered, 0);
124 NDINIT(ndp, LOOKUP, FOLLOW|LOCKLEAF, UIO_SYSSPACE, target, curthread);
129 * XXXKIB This is deadlock-prone as well.
132 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY);
136 NDFREE(ndp, NDF_ONLY_PNBUF);
139 * Sanity check on lower vnode
141 lowerrootvp = ndp->ni_vp;
144 * Check multi null mount to avoid `lock against myself' panic.
146 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) {
147 NULLFSDEBUG("nullfs_mount: multi null mount?\n");
152 xmp = (struct null_mount *) malloc(sizeof(struct null_mount),
153 M_NULLFSMNT, M_WAITOK | M_ZERO);
156 * Save reference to underlying FS
158 xmp->nullm_vfs = lowerrootvp->v_mount;
161 * Save reference. Each mount also holds
162 * a reference on the root vnode.
164 error = null_nodeget(mp, lowerrootvp, &vp);
166 * Make sure the node alias worked
169 free(xmp, M_NULLFSMNT);
174 * Keep a held reference to the root vnode.
175 * It is vrele'd in nullfs_unmount.
178 nullm_rootvp->v_vflag |= VV_ROOT;
179 xmp->nullm_rootvp = nullm_rootvp;
182 * Unlock the node (either the lower or the alias)
186 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) {
188 mp->mnt_flag |= MNT_LOCAL;
192 xmp->nullm_flags |= NULLM_CACHE;
193 if (vfs_getopt(mp->mnt_optnew, "nocache", NULL, NULL) == 0 ||
194 (xmp->nullm_vfs->mnt_kern_flag & MNTK_NULL_NOCACHE) != 0)
195 xmp->nullm_flags &= ~NULLM_CACHE;
198 if ((xmp->nullm_flags & NULLM_CACHE) != 0) {
199 mp->mnt_kern_flag |= lowerrootvp->v_mount->mnt_kern_flag &
200 (MNTK_SHARED_WRITES | MNTK_LOOKUP_SHARED |
201 MNTK_EXTENDED_SHARED);
203 mp->mnt_kern_flag |= MNTK_LOOKUP_EXCL_DOTDOT;
204 mp->mnt_kern_flag |= lowerrootvp->v_mount->mnt_kern_flag &
205 (MNTK_USES_BCACHE | MNTK_NO_IOPF | MNTK_UNMAPPED_BUFS);
209 if ((xmp->nullm_flags & NULLM_CACHE) != 0) {
210 MNT_ILOCK(xmp->nullm_vfs);
211 TAILQ_INSERT_TAIL(&xmp->nullm_vfs->mnt_uppers, mp,
213 MNT_IUNLOCK(xmp->nullm_vfs);
216 vfs_mountedfrom(mp, target);
218 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n",
219 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
224 * Free reference to null layer
227 nullfs_unmount(mp, mntflags)
231 struct null_mount *mntdata;
235 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp);
237 if (mntflags & MNT_FORCE)
242 /* There is 1 extra root vnode reference (nullm_rootvp). */
243 error = vflush(mp, 1, flags, curthread);
248 * Finally, throw away the null_mount structure
250 mntdata = mp->mnt_data;
251 ump = mntdata->nullm_vfs;
252 if ((mntdata->nullm_flags & NULLM_CACHE) != 0) {
254 while ((ump->mnt_kern_flag & MNTK_VGONE_UPPER) != 0) {
255 ump->mnt_kern_flag |= MNTK_VGONE_WAITER;
256 msleep(&ump->mnt_uppers, &ump->mnt_mtx, 0, "vgnupw", 0);
258 TAILQ_REMOVE(&ump->mnt_uppers, mp, mnt_upper_link);
262 free(mntdata, M_NULLFSMNT);
267 nullfs_root(mp, flags, vpp)
274 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp,
275 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
276 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
279 * Return locked reference to root.
281 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
284 ASSERT_VOP_UNLOCKED(vp, "root vnode is locked");
285 vn_lock(vp, flags | LK_RETRY);
291 nullfs_quotactl(mp, cmd, uid, arg)
297 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg);
301 nullfs_statfs(mp, sbp)
306 struct statfs *mstat;
308 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp,
309 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
310 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
312 mstat = malloc(sizeof(struct statfs), M_STATFS, M_WAITOK | M_ZERO);
314 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, mstat);
316 free(mstat, M_STATFS);
320 /* now copy across the "interesting" information and fake the rest */
321 sbp->f_type = mstat->f_type;
322 sbp->f_flags = (sbp->f_flags & (MNT_RDONLY | MNT_NOEXEC | MNT_NOSUID |
323 MNT_UNION | MNT_NOSYMFOLLOW | MNT_AUTOMOUNTED)) |
324 (mstat->f_flags & ~(MNT_ROOTFS | MNT_AUTOMOUNTED));
325 sbp->f_bsize = mstat->f_bsize;
326 sbp->f_iosize = mstat->f_iosize;
327 sbp->f_blocks = mstat->f_blocks;
328 sbp->f_bfree = mstat->f_bfree;
329 sbp->f_bavail = mstat->f_bavail;
330 sbp->f_files = mstat->f_files;
331 sbp->f_ffree = mstat->f_ffree;
333 free(mstat, M_STATFS);
338 nullfs_sync(mp, waitfor)
343 * XXX - Assumes no data cached at null layer.
349 nullfs_vget(mp, ino, flags, vpp)
357 KASSERT((flags & LK_TYPE_MASK) != 0,
358 ("nullfs_vget: no lock requested"));
360 error = VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, flags, vpp);
363 return (null_nodeget(mp, *vpp, vpp));
367 nullfs_fhtovp(mp, fidp, flags, vpp)
375 error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, flags,
379 return (null_nodeget(mp, *vpp, vpp));
383 nullfs_extattrctl(mp, cmd, filename_vp, namespace, attrname)
386 struct vnode *filename_vp;
388 const char *attrname;
391 return (VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd,
392 filename_vp, namespace, attrname));
396 nullfs_reclaim_lowervp(struct mount *mp, struct vnode *lowervp)
400 vp = null_hashget(mp, lowervp);
403 VTONULL(vp)->null_flags |= NULLV_NOUNLOCK;
409 nullfs_unlink_lowervp(struct mount *mp, struct vnode *lowervp)
412 struct null_node *xp;
414 vp = null_hashget(mp, lowervp);
418 xp->null_flags |= NULLV_DROP | NULLV_NOUNLOCK;
422 if (vp->v_usecount == 0) {
424 * If vunref() dropped the last use reference on the
425 * nullfs vnode, it must be reclaimed, and its lock
426 * was split from the lower vnode lock. Need to do
427 * extra unlock before allowing the final vdrop() to
430 KASSERT((vp->v_iflag & VI_DOOMED) != 0,
431 ("not reclaimed nullfs vnode %p", vp));
435 * Otherwise, the nullfs vnode still shares the lock
436 * with the lower vnode, and must not be unlocked.
437 * Also clear the NULLV_NOUNLOCK, the flag is not
438 * relevant for future reclamations.
440 ASSERT_VOP_ELOCKED(vp, "unlink_lowervp");
441 KASSERT((vp->v_iflag & VI_DOOMED) == 0,
442 ("reclaimed nullfs vnode %p", vp));
443 xp->null_flags &= ~NULLV_NOUNLOCK;
448 static struct vfsops null_vfsops = {
449 .vfs_extattrctl = nullfs_extattrctl,
450 .vfs_fhtovp = nullfs_fhtovp,
451 .vfs_init = nullfs_init,
452 .vfs_mount = nullfs_mount,
453 .vfs_quotactl = nullfs_quotactl,
454 .vfs_root = nullfs_root,
455 .vfs_statfs = nullfs_statfs,
456 .vfs_sync = nullfs_sync,
457 .vfs_uninit = nullfs_uninit,
458 .vfs_unmount = nullfs_unmount,
459 .vfs_vget = nullfs_vget,
460 .vfs_reclaim_lowervp = nullfs_reclaim_lowervp,
461 .vfs_unlink_lowervp = nullfs_unlink_lowervp,
464 VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK | VFCF_JAIL);