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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 1.17 2005/07/26 15:43:36 hmp 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/nlookup.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_statfs(struct mount *mp, struct statfs *sbp,
73 static int nullfs_unmount(struct mount *mp, int mntflags, struct thread *td);
74 static int nullfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp);
75 static int nullfs_vptofh(struct vnode *vp, struct fid *fhp);
76 static int nullfs_extattrctl(struct mount *mp, int cmd,
77 const char *attrname, caddr_t arg, struct thread *td);
83 nullfs_mount(struct mount *mp, char *path, caddr_t data, struct thread *td)
86 struct null_args args;
87 struct vnode *lowerrootvp, *vp;
88 struct vnode *nullm_rootvp;
89 struct null_mount *xmp;
92 struct nlookupdata nd;
94 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp);
99 if (mp->mnt_flag & MNT_UPDATE) {
106 error = copyin(data, (caddr_t)&args, sizeof(struct null_args));
111 * Unlock lower node to avoid deadlock.
112 * (XXX) VOP_ISLOCKED is needed?
114 if ((mp->mnt_vnodecovered->v_tag == VT_NULL) &&
115 VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) {
116 VOP_UNLOCK(mp->mnt_vnodecovered, 0, td);
123 error = nlookup_init(&nd, args.target, UIO_USERSPACE, NLC_FOLLOW);
125 error = nlookup(&nd);
127 error = cache_vget(nd.nl_ncp, nd.nl_cred, LK_EXCLUSIVE,
135 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL))
136 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, td);
141 * Sanity check on lower vnode
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); /* XXX */
155 * Save reference to underlying FS
157 xmp->nullm_vfs = lowerrootvp->v_mount;
159 vfs_add_vnodeops(mp, &mp->mnt_vn_norm_ops, null_vnodeop_entries);
162 * Save reference. Each mount also holds
163 * a reference on the root vnode.
165 error = null_node_create(mp, lowerrootvp, &vp);
167 * Unlock the node (either the lower or the alias)
169 VOP_UNLOCK(vp, 0, td);
171 * Make sure the node alias worked
175 free(xmp, M_NULLFSMNT); /* XXX */
180 * Keep a held reference to the root vnode.
181 * It is vrele'd in nullfs_unmount.
184 nullm_rootvp->v_flag |= VROOT;
185 xmp->nullm_rootvp = nullm_rootvp;
186 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL)
187 mp->mnt_flag |= MNT_LOCAL;
188 mp->mnt_data = (qaddr_t) xmp;
191 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
193 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
194 (void)nullfs_statfs(mp, &mp->mnt_stat, td);
195 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n",
196 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntfromname);
201 * Free reference to null layer
204 nullfs_unmount(struct mount *mp, int mntflags, struct thread *td)
210 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp);
212 if (mntflags & MNT_FORCE)
215 /* There is 1 extra root vnode reference (nullm_rootvp). */
216 error = vflush(mp, 1, flags);
221 * Finally, throw away the null_mount structure
223 mntdata = mp->mnt_data;
225 free(mntdata, M_NULLFSMNT);
230 nullfs_root(struct mount *mp, struct vnode **vpp)
232 struct thread *td = curthread; /* XXX */
235 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp,
236 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
237 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
240 * Return locked reference to root.
242 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
246 if (VOP_ISLOCKED(vp, NULL)) {
247 Debugger("root vnode is locked.\n");
252 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
258 nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, caddr_t arg,
261 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td);
265 nullfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *td)
270 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp,
271 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
272 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
274 bzero(&mstat, sizeof(mstat));
276 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td);
280 /* now copy across the "interesting" information and fake the rest */
281 sbp->f_type = mstat.f_type;
282 sbp->f_flags = mstat.f_flags;
283 sbp->f_bsize = mstat.f_bsize;
284 sbp->f_iosize = mstat.f_iosize;
285 sbp->f_blocks = mstat.f_blocks;
286 sbp->f_bfree = mstat.f_bfree;
287 sbp->f_bavail = mstat.f_bavail;
288 sbp->f_files = mstat.f_files;
289 sbp->f_ffree = mstat.f_ffree;
290 if (sbp != &mp->mnt_stat) {
291 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
292 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
298 nullfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp)
301 return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp);
305 nullfs_fhtovp(struct mount *mp, struct fid *fidp, struct vnode **vpp)
308 return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp);
312 nullfs_checkexp(struct mount *mp, struct sockaddr *nam, int *extflagsp,
313 struct ucred **credanonp)
316 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam,
317 extflagsp, credanonp);
321 nullfs_vptofh(struct vnode *vp, struct fid *fhp)
323 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp);
327 nullfs_extattrctl(struct mount *mp, int cmd, const char *attrname, caddr_t arg,
330 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname,
335 static struct vfsops null_vfsops = {
336 .vfs_mount = nullfs_mount,
337 .vfs_unmount = nullfs_unmount,
338 .vfs_root = nullfs_root,
339 .vfs_quotactl = nullfs_quotactl,
340 .vfs_statfs = nullfs_statfs,
341 .vfs_sync = vfs_stdsync,
342 .vfs_vget = nullfs_vget,
343 .vfs_fhtovp = nullfs_fhtovp,
344 .vfs_checkexp = nullfs_checkexp,
345 .vfs_vptofh = nullfs_vptofh,
346 .vfs_init = nullfs_init,
347 .vfs_uninit = nullfs_uninit,
348 .vfs_extattrctl = nullfs_extattrctl
351 VFS_SET(null_vfsops, null, VFCF_LOOPBACK);