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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;
68 static vfs_reclaim_lowervp_t nullfs_reclaim_lowervp;
74 nullfs_mount(struct mount *mp)
77 struct vnode *lowerrootvp, *vp;
78 struct vnode *nullm_rootvp;
79 struct null_mount *xmp;
80 struct thread *td = curthread;
82 int isvnunlocked = 0, len;
83 struct nameidata nd, *ndp = &nd;
85 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp);
87 if (!prison_allow(td->td_ucred, PR_ALLOW_MOUNT_NULLFS))
89 if (mp->mnt_flag & MNT_ROOTFS)
95 if (mp->mnt_flag & MNT_UPDATE) {
97 * Only support update mounts for NFS export.
99 if (vfs_flagopt(mp->mnt_optnew, "export", NULL, 0))
108 error = vfs_getopt(mp->mnt_optnew, "target", (void **)&target, &len);
109 if (error || target[len - 1] != '\0')
113 * Unlock lower node to avoid possible deadlock.
115 if ((mp->mnt_vnodecovered->v_op == &null_vnodeops) &&
116 VOP_ISLOCKED(mp->mnt_vnodecovered) == LK_EXCLUSIVE) {
117 VOP_UNLOCK(mp->mnt_vnodecovered, 0);
123 NDINIT(ndp, LOOKUP, FOLLOW|LOCKLEAF, UIO_SYSSPACE, target, curthread);
128 * XXXKIB This is deadlock-prone as well.
131 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY);
135 NDFREE(ndp, NDF_ONLY_PNBUF);
138 * Sanity check on lower vnode
140 lowerrootvp = ndp->ni_vp;
143 * Check multi null mount to avoid `lock against myself' panic.
145 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) {
146 NULLFSDEBUG("nullfs_mount: multi null mount?\n");
151 xmp = (struct null_mount *) malloc(sizeof(struct null_mount),
152 M_NULLFSMNT, M_WAITOK | M_ZERO);
155 * Save reference to underlying FS
157 xmp->nullm_vfs = lowerrootvp->v_mount;
160 * Save reference. Each mount also holds
161 * a reference on the root vnode.
163 error = null_nodeget(mp, lowerrootvp, &vp);
165 * Make sure the node alias worked
168 free(xmp, M_NULLFSMNT);
173 * Keep a held reference to the root vnode.
174 * It is vrele'd in nullfs_unmount.
177 nullm_rootvp->v_vflag |= VV_ROOT;
178 xmp->nullm_rootvp = nullm_rootvp;
181 * Unlock the node (either the lower or the alias)
185 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) {
187 mp->mnt_flag |= MNT_LOCAL;
191 xmp->nullm_flags |= NULLM_CACHE;
192 if (vfs_getopt(mp->mnt_optnew, "nocache", NULL, NULL) == 0)
193 xmp->nullm_flags &= ~NULLM_CACHE;
196 if ((xmp->nullm_flags & NULLM_CACHE) != 0) {
197 mp->mnt_kern_flag |= lowerrootvp->v_mount->mnt_kern_flag &
198 (MNTK_MPSAFE | MNTK_SHARED_WRITES | MNTK_LOOKUP_SHARED |
199 MNTK_EXTENDED_SHARED);
201 mp->mnt_kern_flag |= MNTK_LOOKUP_EXCL_DOTDOT;
205 if ((xmp->nullm_flags & NULLM_CACHE) != 0) {
206 MNT_ILOCK(xmp->nullm_vfs);
207 TAILQ_INSERT_TAIL(&xmp->nullm_vfs->mnt_uppers, mp,
209 MNT_IUNLOCK(xmp->nullm_vfs);
212 vfs_mountedfrom(mp, target);
214 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n",
215 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
220 * Free reference to null layer
223 nullfs_unmount(mp, mntflags)
227 struct null_mount *mntdata;
231 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp);
233 if (mntflags & MNT_FORCE)
238 /* There is 1 extra root vnode reference (nullm_rootvp). */
239 error = vflush(mp, 1, flags, curthread);
244 * Finally, throw away the null_mount structure
246 mntdata = mp->mnt_data;
247 ump = mntdata->nullm_vfs;
248 if ((mntdata->nullm_flags & NULLM_CACHE) != 0) {
250 while ((ump->mnt_kern_flag & MNTK_VGONE_UPPER) != 0) {
251 ump->mnt_kern_flag |= MNTK_VGONE_WAITER;
252 msleep(&ump->mnt_uppers, &ump->mnt_mtx, 0, "vgnupw", 0);
254 TAILQ_REMOVE(&ump->mnt_uppers, mp, mnt_upper_link);
258 free(mntdata, M_NULLFSMNT);
263 nullfs_root(mp, flags, vpp)
270 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp,
271 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
272 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
275 * Return locked reference to root.
277 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
280 ASSERT_VOP_UNLOCKED(vp, "root vnode is locked");
281 vn_lock(vp, flags | LK_RETRY);
287 nullfs_quotactl(mp, cmd, uid, arg)
293 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg);
297 nullfs_statfs(mp, sbp)
304 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp,
305 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
306 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
308 bzero(&mstat, sizeof(mstat));
310 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat);
314 /* now copy across the "interesting" information and fake the rest */
315 sbp->f_type = mstat.f_type;
316 sbp->f_flags = mstat.f_flags;
317 sbp->f_bsize = mstat.f_bsize;
318 sbp->f_iosize = mstat.f_iosize;
319 sbp->f_blocks = mstat.f_blocks;
320 sbp->f_bfree = mstat.f_bfree;
321 sbp->f_bavail = mstat.f_bavail;
322 sbp->f_files = mstat.f_files;
323 sbp->f_ffree = mstat.f_ffree;
328 nullfs_sync(mp, waitfor)
333 * XXX - Assumes no data cached at null layer.
339 nullfs_vget(mp, ino, flags, vpp)
347 KASSERT((flags & LK_TYPE_MASK) != 0,
348 ("nullfs_vget: no lock requested"));
350 error = VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, flags, vpp);
353 return (null_nodeget(mp, *vpp, vpp));
357 nullfs_fhtovp(mp, fidp, flags, vpp)
365 error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, flags,
369 return (null_nodeget(mp, *vpp, vpp));
373 nullfs_extattrctl(mp, cmd, filename_vp, namespace, attrname)
376 struct vnode *filename_vp;
378 const char *attrname;
381 return (VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd,
382 filename_vp, namespace, attrname));
386 nullfs_reclaim_lowervp(struct mount *mp, struct vnode *lowervp)
390 vp = null_hashget(mp, lowervp);
394 vn_lock(lowervp, LK_EXCLUSIVE | LK_RETRY);
397 static struct vfsops null_vfsops = {
398 .vfs_extattrctl = nullfs_extattrctl,
399 .vfs_fhtovp = nullfs_fhtovp,
400 .vfs_init = nullfs_init,
401 .vfs_mount = nullfs_mount,
402 .vfs_quotactl = nullfs_quotactl,
403 .vfs_root = nullfs_root,
404 .vfs_statfs = nullfs_statfs,
405 .vfs_sync = nullfs_sync,
406 .vfs_uninit = nullfs_uninit,
407 .vfs_unmount = nullfs_unmount,
408 .vfs_vget = nullfs_vget,
409 .vfs_reclaim_lowervp = nullfs_reclaim_lowervp,
412 VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK | VFCF_JAIL);