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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>
54 #include <fs/nullfs/null.h>
56 static MALLOC_DEFINE(M_NULLFSMNT, "nullfs_mount", "NULLFS mount structure");
58 static vfs_fhtovp_t nullfs_fhtovp;
59 static vfs_mount_t nullfs_mount;
60 static vfs_quotactl_t nullfs_quotactl;
61 static vfs_root_t nullfs_root;
62 static vfs_sync_t nullfs_sync;
63 static vfs_statfs_t nullfs_statfs;
64 static vfs_unmount_t nullfs_unmount;
65 static vfs_vget_t nullfs_vget;
66 static vfs_extattrctl_t nullfs_extattrctl;
72 nullfs_mount(struct mount *mp, struct thread *td)
75 struct vnode *lowerrootvp, *vp;
76 struct vnode *nullm_rootvp;
77 struct null_mount *xmp;
79 int isvnunlocked = 0, len;
80 struct nameidata nd, *ndp = &nd;
82 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp);
84 if (mp->mnt_flag & MNT_ROOTFS)
89 if (mp->mnt_flag & MNT_UPDATE) {
91 * Only support update mounts for NFS export.
93 if (vfs_flagopt(mp->mnt_optnew, "export", NULL, 0))
102 error = vfs_getopt(mp->mnt_optnew, "target", (void **)&target, &len);
103 if (error || target[len - 1] != '\0')
107 * Unlock lower node to avoid deadlock.
108 * (XXX) VOP_ISLOCKED is needed?
110 if ((mp->mnt_vnodecovered->v_op == &null_vnodeops) &&
111 VOP_ISLOCKED(mp->mnt_vnodecovered)) {
112 VOP_UNLOCK(mp->mnt_vnodecovered, 0);
118 NDINIT(ndp, LOOKUP, FOLLOW|LOCKLEAF,
119 UIO_SYSSPACE, target, td);
124 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered))
125 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY);
129 NDFREE(ndp, NDF_ONLY_PNBUF);
132 * Sanity check on lower vnode
134 lowerrootvp = ndp->ni_vp;
137 * Check multi null mount to avoid `lock against myself' panic.
139 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) {
140 NULLFSDEBUG("nullfs_mount: multi null mount?\n");
145 xmp = (struct null_mount *) malloc(sizeof(struct null_mount),
146 M_NULLFSMNT, M_WAITOK); /* XXX */
149 * Save reference to underlying FS
151 xmp->nullm_vfs = lowerrootvp->v_mount;
154 * Save reference. Each mount also holds
155 * a reference on the root vnode.
157 error = null_nodeget(mp, lowerrootvp, &vp);
159 * Make sure the node alias worked
164 free(xmp, M_NULLFSMNT); /* XXX */
169 * Keep a held reference to the root vnode.
170 * It is vrele'd in nullfs_unmount.
173 nullm_rootvp->v_vflag |= VV_ROOT;
174 xmp->nullm_rootvp = nullm_rootvp;
177 * Unlock the node (either the lower or the alias)
181 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) {
183 mp->mnt_flag |= MNT_LOCAL;
187 mp->mnt_kern_flag |= lowerrootvp->v_mount->mnt_kern_flag & MNTK_MPSAFE;
192 vfs_mountedfrom(mp, target);
194 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n",
195 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
200 * Free reference to null layer
203 nullfs_unmount(mp, mntflags, td)
212 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp);
214 if (mntflags & MNT_FORCE)
217 /* There is 1 extra root vnode reference (nullm_rootvp). */
218 error = vflush(mp, 1, flags, td);
223 * Finally, throw away the null_mount structure
225 mntdata = mp->mnt_data;
227 free(mntdata, M_NULLFSMNT);
232 nullfs_root(mp, flags, vpp, td)
240 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp,
241 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
242 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
245 * Return locked reference to root.
247 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
251 if (VOP_ISLOCKED(vp))
252 panic("root vnode is locked.\n");
254 vn_lock(vp, flags | LK_RETRY);
260 nullfs_quotactl(mp, cmd, uid, arg, td)
267 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td);
271 nullfs_statfs(mp, sbp, td)
279 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp,
280 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
281 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
283 bzero(&mstat, sizeof(mstat));
285 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td);
289 /* now copy across the "interesting" information and fake the rest */
290 sbp->f_type = mstat.f_type;
291 sbp->f_flags = mstat.f_flags;
292 sbp->f_bsize = mstat.f_bsize;
293 sbp->f_iosize = mstat.f_iosize;
294 sbp->f_blocks = mstat.f_blocks;
295 sbp->f_bfree = mstat.f_bfree;
296 sbp->f_bavail = mstat.f_bavail;
297 sbp->f_files = mstat.f_files;
298 sbp->f_ffree = mstat.f_ffree;
303 nullfs_sync(mp, waitfor, td)
309 * XXX - Assumes no data cached at null layer.
315 nullfs_vget(mp, ino, flags, vpp)
322 error = VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, flags, vpp);
326 return (null_nodeget(mp, *vpp, vpp));
330 nullfs_fhtovp(mp, fidp, vpp)
336 error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp);
340 return (null_nodeget(mp, *vpp, vpp));
344 nullfs_extattrctl(mp, cmd, filename_vp, namespace, attrname, td)
347 struct vnode *filename_vp;
349 const char *attrname;
352 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, filename_vp,
353 namespace, attrname, td);
357 static struct vfsops null_vfsops = {
358 .vfs_extattrctl = nullfs_extattrctl,
359 .vfs_fhtovp = nullfs_fhtovp,
360 .vfs_init = nullfs_init,
361 .vfs_mount = nullfs_mount,
362 .vfs_quotactl = nullfs_quotactl,
363 .vfs_root = nullfs_root,
364 .vfs_statfs = nullfs_statfs,
365 .vfs_sync = nullfs_sync,
366 .vfs_uninit = nullfs_uninit,
367 .vfs_unmount = nullfs_unmount,
368 .vfs_vget = nullfs_vget,
371 VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK);