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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 1.26 2006/09/05 03:48:13 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/nlookup.h>
58 extern struct vop_ops null_vnode_vops;
60 static MALLOC_DEFINE(M_NULLFSMNT, "NULLFS mount", "NULLFS mount structure");
62 static int nullfs_root(struct mount *mp, struct vnode **vpp);
63 static int nullfs_statfs(struct mount *mp, struct statfs *sbp,
70 nullfs_mount(struct mount *mp, char *path, caddr_t data, struct ucred *cred)
73 struct null_args args;
75 struct null_mount *xmp;
77 struct nlookupdata nd;
79 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp);
84 if (mp->mnt_flag & MNT_UPDATE) {
91 error = copyin(data, (caddr_t)&args, sizeof(struct null_args));
99 error = nlookup_init(&nd, args.target, UIO_USERSPACE, NLC_FOLLOW);
101 error = nlookup(&nd);
103 error = cache_vget(nd.nl_ncp, nd.nl_cred, LK_EXCLUSIVE,
107 xmp = (struct null_mount *) kmalloc(sizeof(struct null_mount),
108 M_NULLFSMNT, M_WAITOK); /* XXX */
111 * Save reference to underlying FS
114 * As lite stacking enters the scene, the old way of doing this
115 * -- via the vnode -- is not good enough anymore...
117 xmp->nullm_vfs = nd.nl_ncp->nc_mount;
120 vfs_add_vnodeops(mp, &null_vnode_vops, &mp->mnt_vn_norm_ops);
125 * Keep a held reference to the root vnode.
126 * It is vrele'd in nullfs_unmount.
128 xmp->nullm_rootvp = rootvp;
130 * XXX What's the proper safety condition for querying
131 * the underlying mount? Is this flag tuning necessary
134 if (xmp->nullm_vfs->mnt_flag & MNT_LOCAL)
135 mp->mnt_flag |= MNT_LOCAL;
136 mp->mnt_data = (qaddr_t) xmp;
139 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
141 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
142 (void)nullfs_statfs(mp, &mp->mnt_stat, cred);
143 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n",
144 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntfromname);
149 * Free reference to null layer
152 nullfs_unmount(struct mount *mp, int mntflags)
157 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp);
159 if (mntflags & MNT_FORCE)
163 * Finally, throw away the null_mount structure
165 mntdata = mp->mnt_data;
167 kfree(mntdata, M_NULLFSMNT);
172 nullfs_root(struct mount *mp, struct vnode **vpp)
177 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p)\n", (void *)mp,
178 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp);
181 * Return locked reference to root.
183 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
184 error = vget(vp, LK_EXCLUSIVE | LK_RETRY);
191 nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, caddr_t arg,
194 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, cred);
198 nullfs_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred)
203 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p)\n", (void *)mp,
204 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp);
206 bzero(&mstat, sizeof(mstat));
208 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, cred);
212 /* now copy across the "interesting" information and fake the rest */
213 sbp->f_type = mstat.f_type;
214 sbp->f_flags = mstat.f_flags;
215 sbp->f_bsize = mstat.f_bsize;
216 sbp->f_iosize = mstat.f_iosize;
217 sbp->f_blocks = mstat.f_blocks;
218 sbp->f_bfree = mstat.f_bfree;
219 sbp->f_bavail = mstat.f_bavail;
220 sbp->f_files = mstat.f_files;
221 sbp->f_ffree = mstat.f_ffree;
222 if (sbp != &mp->mnt_stat) {
223 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
224 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
230 nullfs_checkexp(struct mount *mp, struct sockaddr *nam, int *extflagsp,
231 struct ucred **credanonp)
234 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam,
235 extflagsp, credanonp);
239 nullfs_extattrctl(struct mount *mp, int cmd, const char *attrname, caddr_t arg,
242 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname,
247 static struct vfsops null_vfsops = {
248 .vfs_mount = nullfs_mount,
249 .vfs_unmount = nullfs_unmount,
250 .vfs_root = nullfs_root,
251 .vfs_quotactl = nullfs_quotactl,
252 .vfs_statfs = nullfs_statfs,
253 .vfs_sync = vfs_stdsync,
254 .vfs_checkexp = nullfs_checkexp,
255 .vfs_extattrctl = nullfs_extattrctl
258 VFS_SET(null_vfsops, null, VFCF_LOOPBACK);