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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 1.19 2006/01/04 03:09:53 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_checkexp(struct mount *mp, struct sockaddr *nam,
63 int *extflagsp, struct ucred **credanonp);
64 static int nullfs_mount(struct mount *mp, char *path, caddr_t data,
66 static int nullfs_quotactl(struct mount *mp, int cmd, uid_t uid,
67 caddr_t arg, struct thread *td);
68 static int nullfs_root(struct mount *mp, struct vnode **vpp);
69 static int nullfs_statfs(struct mount *mp, struct statfs *sbp,
71 static int nullfs_unmount(struct mount *mp, int mntflags, struct thread *td);
72 static int nullfs_extattrctl(struct mount *mp, int cmd,
73 const char *attrname, caddr_t arg, struct thread *td);
79 nullfs_mount(struct mount *mp, char *path, caddr_t data, struct thread *td)
82 struct null_args args;
84 struct null_mount *xmp;
86 struct nlookupdata nd;
88 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp);
93 if (mp->mnt_flag & MNT_UPDATE) {
100 error = copyin(data, (caddr_t)&args, sizeof(struct null_args));
108 error = nlookup_init(&nd, args.target, UIO_USERSPACE, NLC_FOLLOW);
110 error = nlookup(&nd);
112 error = cache_vget(nd.nl_ncp, nd.nl_cred, LK_EXCLUSIVE,
116 xmp = (struct null_mount *) malloc(sizeof(struct null_mount),
117 M_NULLFSMNT, M_WAITOK); /* XXX */
120 * Save reference to underlying FS
123 * As lite stacking enters the scene, the old way of doing this
124 * -- via the vnode -- is not good enough anymore...
126 xmp->nullm_vfs = nd.nl_ncp->nc_mount;
129 vfs_add_vnodeops(mp, &mp->mnt_vn_norm_ops,
130 null_vnodeop_entries, 0);
132 VOP_UNLOCK(rootvp, 0, td);
135 * Keep a held reference to the root vnode.
136 * It is vrele'd in nullfs_unmount.
138 xmp->nullm_rootvp = rootvp;
140 * XXX What's the proper safety condition for querying
141 * the underlying mount? Is this flag tuning necessary
144 if (xmp->nullm_vfs->mnt_flag & MNT_LOCAL)
145 mp->mnt_flag |= MNT_LOCAL;
146 mp->mnt_data = (qaddr_t) xmp;
149 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
151 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
152 (void)nullfs_statfs(mp, &mp->mnt_stat, td);
153 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n",
154 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntfromname);
159 * Free reference to null layer
162 nullfs_unmount(struct mount *mp, int mntflags, struct thread *td)
167 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp);
169 if (mntflags & MNT_FORCE)
173 * Finally, throw away the null_mount structure
175 mntdata = mp->mnt_data;
177 free(mntdata, M_NULLFSMNT);
182 nullfs_root(struct mount *mp, struct vnode **vpp)
184 struct thread *td = curthread; /* XXX */
187 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p)\n", (void *)mp,
188 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp);
191 * Return locked reference to root.
193 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
197 if (VOP_ISLOCKED(vp, NULL)) {
198 Debugger("root vnode is locked.\n");
203 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
209 nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, caddr_t arg,
212 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td);
216 nullfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *td)
221 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p)\n", (void *)mp,
222 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp);
224 bzero(&mstat, sizeof(mstat));
226 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td);
230 /* now copy across the "interesting" information and fake the rest */
231 sbp->f_type = mstat.f_type;
232 sbp->f_flags = mstat.f_flags;
233 sbp->f_bsize = mstat.f_bsize;
234 sbp->f_iosize = mstat.f_iosize;
235 sbp->f_blocks = mstat.f_blocks;
236 sbp->f_bfree = mstat.f_bfree;
237 sbp->f_bavail = mstat.f_bavail;
238 sbp->f_files = mstat.f_files;
239 sbp->f_ffree = mstat.f_ffree;
240 if (sbp != &mp->mnt_stat) {
241 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
242 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
248 nullfs_checkexp(struct mount *mp, struct sockaddr *nam, int *extflagsp,
249 struct ucred **credanonp)
252 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam,
253 extflagsp, credanonp);
257 nullfs_extattrctl(struct mount *mp, int cmd, const char *attrname, caddr_t arg,
260 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname,
265 static struct vfsops null_vfsops = {
266 .vfs_mount = nullfs_mount,
267 .vfs_unmount = nullfs_unmount,
268 .vfs_root = nullfs_root,
269 .vfs_quotactl = nullfs_quotactl,
270 .vfs_statfs = nullfs_statfs,
271 .vfs_sync = vfs_stdsync,
272 .vfs_checkexp = nullfs_checkexp,
273 .vfs_extattrctl = nullfs_extattrctl
276 VFS_SET(null_vfsops, null, VFCF_LOOPBACK);