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36 * @(#)umap_subr.c 8.9 (Berkeley) 5/14/95
38 * $FreeBSD: src/sys/miscfs/umapfs/umap_subr.c,v 1.19 1999/09/04 11:51:41 bde Exp $
39 * $DragonFly: src/sys/vfs/umapfs/Attic/umap_subr.c,v 1.9 2004/08/13 17:51:14 dillon Exp $
42 #include <sys/param.h>
43 #include <sys/systm.h>
45 #include <sys/vnode.h>
46 #include <sys/mount.h>
47 #include <sys/malloc.h>
50 #define LOG2_SIZEVNODE 7 /* log2(sizeof struct vnode) */
51 #define NUMAPNODECACHE 16
55 * Each cache entry holds a reference to the target vnode
56 * along with a pointer to the alias vnode. When an
57 * entry is added the target vnode is vref'd. When the
58 * alias is removed the target vnode is vrele'd.
61 #define UMAP_NHASH(vp) \
63 [((uintptr_t)(void *)(vp) >> LOG2_SIZEVNODE) & umap_node_hash])
64 static LIST_HEAD(umap_node_hashhead, umap_node) *umap_node_hashtbl;
65 static u_long umap_node_hash;
67 static u_long umap_findid (u_long id, u_long map[][2], int nentries);
68 static int umap_node_alloc (struct mount *mp, struct vnode *lowervp,
71 umap_node_find (struct mount *mp, struct vnode *targetvp);
74 * Initialise cache headers
77 umapfs_init(struct vfsconf *vfsp)
80 printf("umapfs_init\n"); /* printed during system boot */
82 umap_node_hashtbl = hashinit(NUMAPNODECACHE, M_CACHE, &umap_node_hash);
87 * umap_findid is called by various routines in umap_vnodeops.c to
88 * find a user or group id in a map.
91 umap_findid(u_long id, u_long map[][2], int nentries)
95 /* Find uid entry in map */
97 while ((i<nentries) && ((map[i][0]) != id))
107 * umap_reverse_findid is called by umap_getattr() in umap_vnodeops.c to
108 * find a user or group id in a map, in reverse.
111 umap_reverse_findid(u_long id, u_long map[][2], int nentries)
115 /* Find uid entry in map */
117 while ((i<nentries) && ((map[i][1]) != id))
127 * Return alias for target vnode if already exists, else 0.
129 static struct vnode *
130 umap_node_find(struct mount *mp, struct vnode *targetvp)
132 struct thread *td = curthread; /* XXX */
133 struct umap_node_hashhead *hd;
138 printf("umap_node_find(mp = %p, target = %p)\n",
139 (void *)mp, (void *)targetvp);
143 * Find hash base, and then search the (two-way) linked
144 * list looking for a umap_node structure which is referencing
145 * the target vnode. If found, the increment the umap_node
146 * reference count (but NOT the target vnode's vref counter).
148 hd = UMAP_NHASH(targetvp);
150 for (a = hd->lh_first; a != 0; a = a->umap_hash.le_next) {
151 if (a->umap_lowervp == targetvp &&
152 a->umap_vnode->v_mount == mp) {
155 * We need vget for the VXLOCK
156 * stuff, but we don't want to lock
159 if (vget(vp, NULL, 0, td)) {
161 printf ("umap_node_find: vget failed.\n");
170 printf("umap_node_find(%p, %p): NOT found\n",
171 (void *)mp, (void *)targetvp);
178 * Make a new umap_node node.
179 * Vp is the alias vnode, lofsvp is the target vnode.
180 * Maintain a reference to (targetvp).
183 umap_node_alloc(struct mount *mp, struct vnode *lowervp, struct vnode **vpp)
185 struct umap_node_hashhead *hd;
186 struct umap_node *xp;
187 struct vnode *othervp, *vp;
190 /* XXX This routine probably needs a node_alloc lock */
193 * Do the MALLOC before the getnewvnode since doing so afterward
194 * might cause a bogus v_data pointer to get dereferenced
195 * elsewhere if MALLOC should block.
197 MALLOC(xp, struct umap_node *, sizeof(struct umap_node),
200 error = getnewvnode(VT_UMAP, mp, umap_vnode_vops, vpp);
207 vp->v_type = lowervp->v_type;
210 xp->umap_lowervp = lowervp;
212 * Before we insert our new node onto the hash chains,
213 * check to see if someone else has beaten us to it.
214 * (We could have slept in MALLOC.)
216 othervp = umap_node_find(mp, lowervp);
219 vp->v_type = VBAD; /* node is discarded */
220 vp->v_usecount = 0; /* XXX */
224 vref(lowervp); /* Extra vref will be vrele'd in umap_node_create */
225 hd = UMAP_NHASH(lowervp);
226 LIST_INSERT_HEAD(hd, xp, umap_hash);
232 * Try to find an existing umap_node vnode refering
233 * to it, otherwise make a new umap_node vnode which
234 * contains a reference to the target vnode.
237 umap_node_create(struct mount *mp, struct vnode *targetvp,
238 struct vnode **newvpp)
240 struct vnode *aliasvp;
242 aliasvp = umap_node_find(mp, targetvp);
245 * Take another reference to the alias vnode
248 vprint("umap_node_create: exists", aliasvp);
258 printf("umap_node_create: create new alias vnode\n");
261 * Make new vnode reference the umap_node.
263 error = umap_node_alloc(mp, targetvp, &aliasvp);
268 * aliasvp is already vref'd by getnewvnode()
275 vprint("umap_node_create: alias", aliasvp);
276 vprint("umap_node_create: target", targetvp);
284 int umap_checkvp_barrier = 1;
286 umap_checkvp(struct vnode *vp, char *fil, int lno)
288 struct umap_node *a = VTOUMAP(vp);
291 * Can't do this check because vop_reclaim runs
292 * with funny vop vector.
294 if (vp->v_vops != umap_vnode_vops) {
295 printf ("umap_checkvp: on non-umap-node\n");
296 while (umap_checkvp_barrier) /*WAIT*/ ;
297 panic("umap_checkvp");
300 if (a->umap_lowervp == NULL) {
301 /* Should never happen */
303 printf("vp = %p, ZERO ptr\n", (void *)vp);
304 for (p = (u_long *) a, i = 0; i < 8; i++)
305 printf(" %p", (void *)p[i]);
307 /* wait for debugger */
308 while (umap_checkvp_barrier) /*WAIT*/ ;
309 panic("umap_checkvp");
311 if (a->umap_lowervp->v_usecount < 1) {
313 printf("vp = %p, unref'ed lowervp\n", (void *)vp);
314 for (p = (u_long *) a, i = 0; i < 8; i++)
315 printf(" %p", (void *)p[i]);
317 /* wait for debugger */
318 while (umap_checkvp_barrier) /*WAIT*/ ;
319 panic ("umap with unref'ed lowervp");
322 printf("umap %x/%d -> %x/%d [%s, %d]\n",
323 a->umap_vnode, a->umap_vnode->v_usecount,
324 a->umap_lowervp, a->umap_lowervp->v_usecount,
327 return (a->umap_lowervp);
329 #endif /* DIAGNOSTIC */
331 /* umap_mapids maps all of the ids in a credential, both user and group. */
334 umap_mapids(struct mount *v_mount, struct ucred *credp)
343 /* Find uid entry in map */
345 uid = (uid_t) umap_findid(credp->cr_uid,
346 MOUNTTOUMAPMOUNT(v_mount)->info_mapdata,
347 MOUNTTOUMAPMOUNT(v_mount)->info_nentries);
352 credp->cr_uid = (uid_t) NOBODY;
355 /* cr_gid is the same as cr_groups[0] in 4BSD */
357 /* Find gid entry in map */
359 gid = (gid_t) umap_findid(credp->cr_gid,
360 MOUNTTOUMAPMOUNT(v_mount)->info_gmapdata,
361 MOUNTTOUMAPMOUNT(v_mount)->info_gnentries);
366 credp->cr_gid = NULLGROUP;
369 /* Now we must map each of the set of groups in the cr_groups
373 while (credp->cr_groups[i] != 0) {
374 gid = (gid_t) umap_findid(credp->cr_groups[i],
375 MOUNTTOUMAPMOUNT(v_mount)->info_gmapdata,
376 MOUNTTOUMAPMOUNT(v_mount)->info_gnentries);
379 credp->cr_groups[i++] = gid;
381 credp->cr_groups[i++] = NULLGROUP;