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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 1.13 2004/10/12 19:21:04 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>
58 extern struct vnodeopv_entry_desc null_vnodeop_entries[];
60 static MALLOC_DEFINE(M_NULLFSMNT, "NULLFS mount", "NULLFS mount structure");
62 static int nullfs_fhtovp(struct mount *mp, struct fid *fidp,
64 static int nullfs_checkexp(struct mount *mp, struct sockaddr *nam,
65 int *extflagsp, struct ucred **credanonp);
66 static int nullfs_mount(struct mount *mp, char *path, caddr_t data,
68 static int nullfs_quotactl(struct mount *mp, int cmd, uid_t uid,
69 caddr_t arg, struct thread *td);
70 static int nullfs_root(struct mount *mp, struct vnode **vpp);
71 static int nullfs_start(struct mount *mp, int flags, struct thread *td);
72 static int nullfs_statfs(struct mount *mp, struct statfs *sbp,
74 static int nullfs_sync(struct mount *mp, int waitfor, struct thread *td);
75 static int nullfs_unmount(struct mount *mp, int mntflags, struct thread *td);
76 static int nullfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp);
77 static int nullfs_vptofh(struct vnode *vp, struct fid *fhp);
78 static int nullfs_extattrctl(struct mount *mp, int cmd,
79 const char *attrname, caddr_t arg, struct thread *td);
85 nullfs_mount(struct mount *mp, char *path, caddr_t data, struct thread *td)
88 struct null_args args;
89 struct vnode *lowerrootvp, *vp;
90 struct vnode *nullm_rootvp;
91 struct null_mount *xmp;
96 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp);
101 if (mp->mnt_flag & MNT_UPDATE) {
108 error = copyin(data, (caddr_t)&args, sizeof(struct null_args));
113 * Unlock lower node to avoid deadlock.
114 * (XXX) VOP_ISLOCKED is needed?
116 if ((mp->mnt_vnodecovered->v_tag == VT_NULL) &&
117 VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) {
118 VOP_UNLOCK(mp->mnt_vnodecovered, 0, td);
124 NDINIT(&nd, NAMEI_LOOKUP, CNP_FOLLOW | CNP_WANTPARENT | CNP_LOCKLEAF,
125 UIO_USERSPACE, args.target, td);
130 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL))
131 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, td);
135 NDFREE(&nd, NDF_ONLY_PNBUF);
138 * Sanity check on lower vnode
140 lowerrootvp = nd.ni_vp;
146 * Check multi null mount to avoid `lock against myself' panic.
148 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) {
149 NULLFSDEBUG("nullfs_mount: multi null mount?\n");
154 xmp = (struct null_mount *) malloc(sizeof(struct null_mount),
155 M_NULLFSMNT, M_WAITOK); /* XXX */
158 * Save reference to underlying FS
160 xmp->nullm_vfs = lowerrootvp->v_mount;
162 vfs_add_vnodeops(&mp->mnt_vn_ops, null_vnodeop_entries);
165 * Save reference. Each mount also holds
166 * a reference on the root vnode.
168 error = null_node_create(mp, lowerrootvp, &vp);
170 * Unlock the node (either the lower or the alias)
172 VOP_UNLOCK(vp, 0, td);
174 * Make sure the node alias worked
178 free(xmp, M_NULLFSMNT); /* XXX */
183 * Keep a held reference to the root vnode.
184 * It is vrele'd in nullfs_unmount.
187 nullm_rootvp->v_flag |= VROOT;
188 xmp->nullm_rootvp = nullm_rootvp;
189 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL)
190 mp->mnt_flag |= MNT_LOCAL;
191 mp->mnt_data = (qaddr_t) xmp;
194 (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
195 bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
196 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
198 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
199 (void)nullfs_statfs(mp, &mp->mnt_stat, td);
200 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n",
201 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
206 * VFS start. Nothing needed here - the start routine
207 * on the underlying filesystem will have been called
208 * when that filesystem was mounted.
211 nullfs_start(struct mount *mp, int flags, struct thread *td)
214 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, td); */
218 * Free reference to null layer
221 nullfs_unmount(struct mount *mp, int mntflags, struct thread *td)
227 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp);
229 if (mntflags & MNT_FORCE)
232 /* There is 1 extra root vnode reference (nullm_rootvp). */
233 error = vflush(mp, 1, flags);
238 * Finally, throw away the null_mount structure
240 mntdata = mp->mnt_data;
242 free(mntdata, M_NULLFSMNT);
247 nullfs_root(struct mount *mp, struct vnode **vpp)
249 struct thread *td = curthread; /* XXX */
252 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp,
253 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
254 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
257 * Return locked reference to root.
259 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
263 if (VOP_ISLOCKED(vp, NULL)) {
264 Debugger("root vnode is locked.\n");
269 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
275 nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, caddr_t arg,
278 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td);
282 nullfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *td)
287 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp,
288 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
289 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
291 bzero(&mstat, sizeof(mstat));
293 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td);
297 /* now copy across the "interesting" information and fake the rest */
298 sbp->f_type = mstat.f_type;
299 sbp->f_flags = mstat.f_flags;
300 sbp->f_bsize = mstat.f_bsize;
301 sbp->f_iosize = mstat.f_iosize;
302 sbp->f_blocks = mstat.f_blocks;
303 sbp->f_bfree = mstat.f_bfree;
304 sbp->f_bavail = mstat.f_bavail;
305 sbp->f_files = mstat.f_files;
306 sbp->f_ffree = mstat.f_ffree;
307 if (sbp != &mp->mnt_stat) {
308 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
309 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
310 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
316 nullfs_sync(struct mount *mp, int waitfor, struct thread *td)
319 * XXX - Assumes no data cached at null layer.
325 nullfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp)
328 return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp);
332 nullfs_fhtovp(struct mount *mp, struct fid *fidp, struct vnode **vpp)
335 return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp);
339 nullfs_checkexp(struct mount *mp, struct sockaddr *nam, int *extflagsp,
340 struct ucred **credanonp)
343 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam,
344 extflagsp, credanonp);
348 nullfs_vptofh(struct vnode *vp, struct fid *fhp)
350 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp);
354 nullfs_extattrctl(struct mount *mp, int cmd, const char *attrname, caddr_t arg,
357 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname,
362 static struct vfsops null_vfsops = {
379 VFS_SET(null_vfsops, null, VFCF_LOOPBACK);