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36 * @(#)null_vfsops.c 8.2 (Berkeley) 1/21/94
38 * @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92
39 * $FreeBSD: src/sys/miscfs/nullfs/null_vfsops.c,v 1.35.2.3 2001/07/26 20:37:11 iedowse Exp $
40 * $DragonFly: src/sys/vfs/nullfs/null_vfsops.c,v 1.2 2003/06/17 04:28:42 dillon Exp $
45 * (See null_vnops.c for a description of what this does.)
48 #include <sys/param.h>
49 #include <sys/systm.h>
50 #include <sys/kernel.h>
52 #include <sys/malloc.h>
53 #include <sys/vnode.h>
54 #include <sys/mount.h>
55 #include <sys/namei.h>
56 #include <miscfs/nullfs/null.h>
58 static MALLOC_DEFINE(M_NULLFSMNT, "NULLFS mount", "NULLFS mount structure");
60 static int nullfs_fhtovp(struct mount *mp, struct fid *fidp,
62 static int nullfs_checkexp(struct mount *mp, struct sockaddr *nam,
63 int *extflagsp, struct ucred **credanonp);
64 static int nullfs_mount(struct mount *mp, char *path, caddr_t data,
65 struct nameidata *ndp, struct proc *p);
66 static int nullfs_quotactl(struct mount *mp, int cmd, uid_t uid,
67 caddr_t arg, struct proc *p);
68 static int nullfs_root(struct mount *mp, struct vnode **vpp);
69 static int nullfs_start(struct mount *mp, int flags, struct proc *p);
70 static int nullfs_statfs(struct mount *mp, struct statfs *sbp,
72 static int nullfs_sync(struct mount *mp, int waitfor,
73 struct ucred *cred, struct proc *p);
74 static int nullfs_unmount(struct mount *mp, int mntflags, struct proc *p);
75 static int nullfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp);
76 static int nullfs_vptofh(struct vnode *vp, struct fid *fhp);
77 static int nullfs_extattrctl(struct mount *mp, int cmd,
78 const char *attrname, caddr_t arg, struct proc *p);
84 nullfs_mount(mp, path, data, ndp, p)
88 struct nameidata *ndp;
92 struct null_args args;
93 struct vnode *lowerrootvp, *vp;
94 struct vnode *nullm_rootvp;
95 struct null_mount *xmp;
99 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp);
104 if (mp->mnt_flag & MNT_UPDATE) {
106 /* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, p);*/
112 error = copyin(data, (caddr_t)&args, sizeof(struct null_args));
117 * Unlock lower node to avoid deadlock.
118 * (XXX) VOP_ISLOCKED is needed?
120 if ((mp->mnt_vnodecovered->v_op == null_vnodeop_p) &&
121 VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) {
122 VOP_UNLOCK(mp->mnt_vnodecovered, 0, p);
128 NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF,
129 UIO_USERSPACE, args.target, p);
134 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL))
135 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, p);
139 NDFREE(ndp, NDF_ONLY_PNBUF);
142 * Sanity check on lower vnode
144 lowerrootvp = ndp->ni_vp;
147 ndp->ni_dvp = NULLVP;
150 * Check multi null mount to avoid `lock against myself' panic.
152 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) {
153 NULLFSDEBUG("nullfs_mount: multi null mount?\n");
158 xmp = (struct null_mount *) malloc(sizeof(struct null_mount),
159 M_NULLFSMNT, M_WAITOK); /* XXX */
162 * Save reference to underlying FS
164 xmp->nullm_vfs = lowerrootvp->v_mount;
167 * Save reference. Each mount also holds
168 * a reference on the root vnode.
170 error = null_node_create(mp, lowerrootvp, &vp);
172 * Unlock the node (either the lower or the alias)
174 VOP_UNLOCK(vp, 0, p);
176 * Make sure the node alias worked
180 free(xmp, M_NULLFSMNT); /* XXX */
185 * Keep a held reference to the root vnode.
186 * It is vrele'd in nullfs_unmount.
189 nullm_rootvp->v_flag |= VROOT;
190 xmp->nullm_rootvp = nullm_rootvp;
191 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL)
192 mp->mnt_flag |= MNT_LOCAL;
193 mp->mnt_data = (qaddr_t) xmp;
196 (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
197 bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
198 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
200 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
201 (void)nullfs_statfs(mp, &mp->mnt_stat, p);
202 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n",
203 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
208 * VFS start. Nothing needed here - the start routine
209 * on the underlying filesystem will have been called
210 * when that filesystem was mounted.
213 nullfs_start(mp, flags, p)
219 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, p); */
223 * Free reference to null layer
226 nullfs_unmount(mp, mntflags, p)
235 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp);
237 if (mntflags & MNT_FORCE)
240 /* There is 1 extra root vnode reference (nullm_rootvp). */
241 error = vflush(mp, 1, flags);
246 * Finally, throw away the null_mount structure
248 mntdata = mp->mnt_data;
250 free(mntdata, M_NULLFSMNT);
259 struct proc *p = curproc; /* XXX */
262 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp,
263 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
264 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
267 * Return locked reference to root.
269 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
273 if (VOP_ISLOCKED(vp, NULL)) {
274 Debugger("root vnode is locked.\n");
279 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
285 nullfs_quotactl(mp, cmd, uid, arg, p)
292 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, p);
296 nullfs_statfs(mp, sbp, p)
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, p);
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;
324 if (sbp != &mp->mnt_stat) {
325 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
326 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
327 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
333 nullfs_sync(mp, waitfor, cred, p)
340 * XXX - Assumes no data cached at null layer.
346 nullfs_vget(mp, ino, vpp)
352 return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp);
356 nullfs_fhtovp(mp, fidp, vpp)
362 return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp);
366 nullfs_checkexp(mp, nam, extflagsp, credanonp)
368 struct sockaddr *nam;
370 struct ucred **credanonp;
373 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam,
374 extflagsp, credanonp);
378 nullfs_vptofh(vp, fhp)
382 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp);
386 nullfs_extattrctl(mp, cmd, attrname, arg, p)
389 const char *attrname;
393 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname,
398 static struct vfsops null_vfsops = {
415 VFS_SET(null_vfsops, null, VFCF_LOOPBACK);