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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 1.21 2006/05/06 18:48:53 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 vnodeopv_entry_desc null_vnodeop_entries[];
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 *) malloc(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, &mp->mnt_vn_norm_ops,
121 null_vnodeop_entries, 0);
123 VOP_UNLOCK(rootvp, 0);
126 * Keep a held reference to the root vnode.
127 * It is vrele'd in nullfs_unmount.
129 xmp->nullm_rootvp = rootvp;
131 * XXX What's the proper safety condition for querying
132 * the underlying mount? Is this flag tuning necessary
135 if (xmp->nullm_vfs->mnt_flag & MNT_LOCAL)
136 mp->mnt_flag |= MNT_LOCAL;
137 mp->mnt_data = (qaddr_t) xmp;
140 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
142 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
143 (void)nullfs_statfs(mp, &mp->mnt_stat, cred);
144 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n",
145 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntfromname);
150 * Free reference to null layer
153 nullfs_unmount(struct mount *mp, int mntflags)
158 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp);
160 if (mntflags & MNT_FORCE)
164 * Finally, throw away the null_mount structure
166 mntdata = mp->mnt_data;
168 free(mntdata, M_NULLFSMNT);
173 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;
187 if (VOP_ISLOCKED(vp, NULL)) {
188 Debugger("root vnode is locked.\n");
193 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
199 nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, caddr_t arg,
202 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, cred);
206 nullfs_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred)
211 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p)\n", (void *)mp,
212 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp);
214 bzero(&mstat, sizeof(mstat));
216 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, cred);
220 /* now copy across the "interesting" information and fake the rest */
221 sbp->f_type = mstat.f_type;
222 sbp->f_flags = mstat.f_flags;
223 sbp->f_bsize = mstat.f_bsize;
224 sbp->f_iosize = mstat.f_iosize;
225 sbp->f_blocks = mstat.f_blocks;
226 sbp->f_bfree = mstat.f_bfree;
227 sbp->f_bavail = mstat.f_bavail;
228 sbp->f_files = mstat.f_files;
229 sbp->f_ffree = mstat.f_ffree;
230 if (sbp != &mp->mnt_stat) {
231 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
232 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
238 nullfs_checkexp(struct mount *mp, struct sockaddr *nam, int *extflagsp,
239 struct ucred **credanonp)
242 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam,
243 extflagsp, credanonp);
247 nullfs_extattrctl(struct mount *mp, int cmd, const char *attrname, caddr_t arg,
250 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname,
255 static struct vfsops null_vfsops = {
256 .vfs_mount = nullfs_mount,
257 .vfs_unmount = nullfs_unmount,
258 .vfs_root = nullfs_root,
259 .vfs_quotactl = nullfs_quotactl,
260 .vfs_statfs = nullfs_statfs,
261 .vfs_sync = vfs_stdsync,
262 .vfs_checkexp = nullfs_checkexp,
263 .vfs_extattrctl = nullfs_extattrctl
266 VFS_SET(null_vfsops, null, VFCF_LOOPBACK);