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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)
77 struct vnode *lowerrootvp;
78 struct vnode *nullm_rootvp;
79 struct null_mount *xmp;
81 struct nameidata nd, *ndp;
86 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp);
88 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);
119 isvnunlocked = false;
126 NDINIT(ndp, LOOKUP, FOLLOW|LOCKLEAF, UIO_SYSSPACE, target, curthread);
131 * XXXKIB This is deadlock-prone as well.
134 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY);
138 NDFREE(ndp, NDF_ONLY_PNBUF);
141 * Sanity check on lower vnode
143 lowerrootvp = ndp->ni_vp;
146 * Check multi null mount to avoid `lock against myself' panic.
148 if (mp->mnt_vnodecovered->v_op == &null_vnodeops) {
149 nn = VTONULL(mp->mnt_vnodecovered);
150 if (nn == NULL || lowerrootvp == nn->null_lowervp) {
151 NULLFSDEBUG("nullfs_mount: multi null mount?\n");
157 xmp = (struct null_mount *) malloc(sizeof(struct null_mount),
158 M_NULLFSMNT, M_WAITOK | M_ZERO);
161 * Save pointer to underlying FS and the reference to the
164 xmp->nullm_vfs = lowerrootvp->v_mount;
166 xmp->nullm_lowerrootvp = lowerrootvp;
170 * Make sure the node alias worked.
172 error = null_nodeget(mp, lowerrootvp, &nullm_rootvp);
175 free(xmp, M_NULLFSMNT);
179 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) {
181 mp->mnt_flag |= MNT_LOCAL;
185 xmp->nullm_flags |= NULLM_CACHE;
186 if (vfs_getopt(mp->mnt_optnew, "nocache", NULL, NULL) == 0 ||
187 (xmp->nullm_vfs->mnt_kern_flag & MNTK_NULL_NOCACHE) != 0)
188 xmp->nullm_flags &= ~NULLM_CACHE;
191 if ((xmp->nullm_flags & NULLM_CACHE) != 0) {
192 mp->mnt_kern_flag |= lowerrootvp->v_mount->mnt_kern_flag &
193 (MNTK_SHARED_WRITES | MNTK_LOOKUP_SHARED |
194 MNTK_EXTENDED_SHARED);
196 mp->mnt_kern_flag |= MNTK_LOOKUP_EXCL_DOTDOT | MNTK_NOMSYNC;
197 mp->mnt_kern_flag |= lowerrootvp->v_mount->mnt_kern_flag &
198 (MNTK_USES_BCACHE | MNTK_NO_IOPF | MNTK_UNMAPPED_BUFS);
201 if ((xmp->nullm_flags & NULLM_CACHE) != 0) {
202 MNT_ILOCK(xmp->nullm_vfs);
203 TAILQ_INSERT_TAIL(&xmp->nullm_vfs->mnt_uppers, mp,
205 MNT_IUNLOCK(xmp->nullm_vfs);
208 vfs_mountedfrom(mp, target);
211 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n",
212 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
217 * Free reference to null layer
220 nullfs_unmount(mp, mntflags)
224 struct null_mount *mntdata;
228 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp);
230 if (mntflags & MNT_FORCE)
236 /* There is 1 extra root vnode reference (nullm_rootvp). */
237 error = vflush(mp, 0, flags, curthread);
241 if (mp->mnt_nvnodelistsize == 0) {
246 if ((mntflags & MNT_FORCE) == 0)
251 * Finally, throw away the null_mount structure
253 mntdata = mp->mnt_data;
254 ump = mntdata->nullm_vfs;
255 if ((mntdata->nullm_flags & NULLM_CACHE) != 0) {
257 while ((ump->mnt_kern_flag & MNTK_VGONE_UPPER) != 0) {
258 ump->mnt_kern_flag |= MNTK_VGONE_WAITER;
259 msleep(&ump->mnt_uppers, &ump->mnt_mtx, 0, "vgnupw", 0);
261 TAILQ_REMOVE(&ump->mnt_uppers, mp, mnt_upper_link);
264 vrele(mntdata->nullm_lowerrootvp);
266 free(mntdata, M_NULLFSMNT);
271 nullfs_root(mp, flags, vpp)
277 struct null_mount *mntdata;
280 mntdata = MOUNTTONULLMOUNT(mp);
281 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p)\n", mp,
282 mntdata->nullm_lowerrootvp);
284 error = vget(mntdata->nullm_lowerrootvp, flags);
286 error = null_nodeget(mp, mntdata->nullm_lowerrootvp, &vp);
295 nullfs_quotactl(mp, cmd, uid, arg)
301 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg);
305 nullfs_statfs(mp, sbp)
310 struct statfs *mstat;
312 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp,
313 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
314 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
316 mstat = malloc(sizeof(struct statfs), M_STATFS, M_WAITOK | M_ZERO);
318 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, mstat);
320 free(mstat, M_STATFS);
324 /* now copy across the "interesting" information and fake the rest */
325 sbp->f_type = mstat->f_type;
326 sbp->f_flags = (sbp->f_flags & (MNT_RDONLY | MNT_NOEXEC | MNT_NOSUID |
327 MNT_UNION | MNT_NOSYMFOLLOW | MNT_AUTOMOUNTED)) |
328 (mstat->f_flags & ~(MNT_ROOTFS | MNT_AUTOMOUNTED));
329 sbp->f_bsize = mstat->f_bsize;
330 sbp->f_iosize = mstat->f_iosize;
331 sbp->f_blocks = mstat->f_blocks;
332 sbp->f_bfree = mstat->f_bfree;
333 sbp->f_bavail = mstat->f_bavail;
334 sbp->f_files = mstat->f_files;
335 sbp->f_ffree = mstat->f_ffree;
337 free(mstat, M_STATFS);
342 nullfs_sync(mp, waitfor)
347 * XXX - Assumes no data cached at null layer.
353 nullfs_vget(mp, ino, flags, vpp)
361 KASSERT((flags & LK_TYPE_MASK) != 0,
362 ("nullfs_vget: no lock requested"));
364 error = VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, flags, vpp);
367 return (null_nodeget(mp, *vpp, vpp));
371 nullfs_fhtovp(mp, fidp, flags, vpp)
379 error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, flags,
383 return (null_nodeget(mp, *vpp, vpp));
387 nullfs_extattrctl(mp, cmd, filename_vp, namespace, attrname)
390 struct vnode *filename_vp;
392 const char *attrname;
395 return (VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd,
396 filename_vp, namespace, attrname));
400 nullfs_reclaim_lowervp(struct mount *mp, struct vnode *lowervp)
404 vp = null_hashget(mp, lowervp);
407 VTONULL(vp)->null_flags |= NULLV_NOUNLOCK;
413 nullfs_unlink_lowervp(struct mount *mp, struct vnode *lowervp)
416 struct null_node *xp;
418 vp = null_hashget(mp, lowervp);
422 xp->null_flags |= NULLV_DROP | NULLV_NOUNLOCK;
426 if (vp->v_usecount == 0) {
428 * If vunref() dropped the last use reference on the
429 * nullfs vnode, it must be reclaimed, and its lock
430 * was split from the lower vnode lock. Need to do
431 * extra unlock before allowing the final vdrop() to
434 KASSERT(VN_IS_DOOMED(vp),
435 ("not reclaimed nullfs vnode %p", vp));
439 * Otherwise, the nullfs vnode still shares the lock
440 * with the lower vnode, and must not be unlocked.
441 * Also clear the NULLV_NOUNLOCK, the flag is not
442 * relevant for future reclamations.
444 ASSERT_VOP_ELOCKED(vp, "unlink_lowervp");
445 KASSERT(!VN_IS_DOOMED(vp),
446 ("reclaimed nullfs vnode %p", vp));
447 xp->null_flags &= ~NULLV_NOUNLOCK;
452 static struct vfsops null_vfsops = {
453 .vfs_extattrctl = nullfs_extattrctl,
454 .vfs_fhtovp = nullfs_fhtovp,
455 .vfs_init = nullfs_init,
456 .vfs_mount = nullfs_mount,
457 .vfs_quotactl = nullfs_quotactl,
458 .vfs_root = nullfs_root,
459 .vfs_statfs = nullfs_statfs,
460 .vfs_sync = nullfs_sync,
461 .vfs_uninit = nullfs_uninit,
462 .vfs_unmount = nullfs_unmount,
463 .vfs_vget = nullfs_vget,
464 .vfs_reclaim_lowervp = nullfs_reclaim_lowervp,
465 .vfs_unlink_lowervp = nullfs_unlink_lowervp,
468 VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK | VFCF_JAIL);