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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 1.11 2004/08/17 18:57:34 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,
67 struct nameidata *ndp, struct thread *td);
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 nameidata *ndp,
89 struct null_args args;
90 struct vnode *lowerrootvp, *vp;
91 struct vnode *nullm_rootvp;
92 struct null_mount *xmp;
96 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp);
101 if (mp->mnt_flag & MNT_UPDATE) {
103 /* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, p);*/
109 error = copyin(data, (caddr_t)&args, sizeof(struct null_args));
114 * Unlock lower node to avoid deadlock.
115 * (XXX) VOP_ISLOCKED is needed?
117 if ((mp->mnt_vnodecovered->v_tag == VT_NULL) &&
118 VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) {
119 VOP_UNLOCK(mp->mnt_vnodecovered, NULL, 0, td);
125 NDINIT(ndp, NAMEI_LOOKUP, CNP_FOLLOW | CNP_WANTPARENT | CNP_LOCKLEAF,
126 UIO_USERSPACE, args.target, td);
131 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL))
132 vn_lock(mp->mnt_vnodecovered, NULL, LK_EXCLUSIVE | LK_RETRY, td);
136 NDFREE(ndp, NDF_ONLY_PNBUF);
139 * Sanity check on lower vnode
141 lowerrootvp = ndp->ni_vp;
144 ndp->ni_dvp = NULLVP;
147 * Check multi null mount to avoid `lock against myself' panic.
149 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) {
150 NULLFSDEBUG("nullfs_mount: multi null mount?\n");
155 xmp = (struct null_mount *) malloc(sizeof(struct null_mount),
156 M_NULLFSMNT, M_WAITOK); /* XXX */
159 * Save reference to underlying FS
161 xmp->nullm_vfs = lowerrootvp->v_mount;
163 vfs_add_vnodeops(&mp->mnt_vn_ops, null_vnodeop_entries);
166 * Save reference. Each mount also holds
167 * a reference on the root vnode.
169 error = null_node_create(mp, lowerrootvp, &vp);
171 * Unlock the node (either the lower or the alias)
173 VOP_UNLOCK(vp, NULL, 0, td);
175 * Make sure the node alias worked
179 free(xmp, M_NULLFSMNT); /* XXX */
184 * Keep a held reference to the root vnode.
185 * It is vrele'd in nullfs_unmount.
188 nullm_rootvp->v_flag |= VROOT;
189 xmp->nullm_rootvp = nullm_rootvp;
190 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL)
191 mp->mnt_flag |= MNT_LOCAL;
192 mp->mnt_data = (qaddr_t) xmp;
195 (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
196 bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
197 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
199 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
200 (void)nullfs_statfs(mp, &mp->mnt_stat, td);
201 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n",
202 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
207 * VFS start. Nothing needed here - the start routine
208 * on the underlying filesystem will have been called
209 * when that filesystem was mounted.
212 nullfs_start(struct mount *mp, int flags, struct thread *td)
215 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, td); */
219 * Free reference to null layer
222 nullfs_unmount(struct mount *mp, int mntflags, struct thread *td)
228 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp);
230 if (mntflags & MNT_FORCE)
233 /* There is 1 extra root vnode reference (nullm_rootvp). */
234 error = vflush(mp, 1, flags);
239 * Finally, throw away the null_mount structure
241 mntdata = mp->mnt_data;
243 free(mntdata, M_NULLFSMNT);
248 nullfs_root(struct mount *mp, struct vnode **vpp)
250 struct thread *td = curthread; /* XXX */
253 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp,
254 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
255 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
258 * Return locked reference to root.
260 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
264 if (VOP_ISLOCKED(vp, NULL)) {
265 Debugger("root vnode is locked.\n");
270 vn_lock(vp, NULL, LK_EXCLUSIVE | LK_RETRY, td);
276 nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, caddr_t arg,
279 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td);
283 nullfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *td)
288 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp,
289 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
290 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
292 bzero(&mstat, sizeof(mstat));
294 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td);
298 /* now copy across the "interesting" information and fake the rest */
299 sbp->f_type = mstat.f_type;
300 sbp->f_flags = mstat.f_flags;
301 sbp->f_bsize = mstat.f_bsize;
302 sbp->f_iosize = mstat.f_iosize;
303 sbp->f_blocks = mstat.f_blocks;
304 sbp->f_bfree = mstat.f_bfree;
305 sbp->f_bavail = mstat.f_bavail;
306 sbp->f_files = mstat.f_files;
307 sbp->f_ffree = mstat.f_ffree;
308 if (sbp != &mp->mnt_stat) {
309 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
310 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
311 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
317 nullfs_sync(struct mount *mp, int waitfor, struct thread *td)
320 * XXX - Assumes no data cached at null layer.
326 nullfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp)
329 return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp);
333 nullfs_fhtovp(struct mount *mp, struct fid *fidp, struct vnode **vpp)
336 return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp);
340 nullfs_checkexp(struct mount *mp, struct sockaddr *nam, int *extflagsp,
341 struct ucred **credanonp)
344 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam,
345 extflagsp, credanonp);
349 nullfs_vptofh(struct vnode *vp, struct fid *fhp)
351 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp);
355 nullfs_extattrctl(struct mount *mp, int cmd, const char *attrname, caddr_t arg,
358 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname,
363 static struct vfsops null_vfsops = {
380 VFS_SET(null_vfsops, null, VFCF_LOOPBACK);