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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 $
41 #include <sys/param.h>
42 #include <sys/systm.h>
44 #include <sys/vnode.h>
45 #include <sys/mount.h>
46 #include <sys/malloc.h>
47 #include <miscfs/umapfs/umap.h>
49 #define LOG2_SIZEVNODE 7 /* log2(sizeof struct vnode) */
50 #define NUMAPNODECACHE 16
54 * Each cache entry holds a reference to the target vnode
55 * along with a pointer to the alias vnode. When an
56 * entry is added the target vnode is VREF'd. When the
57 * alias is removed the target vnode is vrele'd.
60 #define UMAP_NHASH(vp) \
62 [((uintptr_t)(void *)(vp) >> LOG2_SIZEVNODE) & umap_node_hash])
63 static LIST_HEAD(umap_node_hashhead, umap_node) *umap_node_hashtbl;
64 static u_long umap_node_hash;
66 static u_long umap_findid __P((u_long id, u_long map[][2], int nentries));
67 static int umap_node_alloc __P((struct mount *mp, struct vnode *lowervp,
70 umap_node_find __P((struct mount *mp, struct vnode *targetvp));
73 * Initialise cache headers
81 printf("umapfs_init\n"); /* printed during system boot */
83 umap_node_hashtbl = hashinit(NUMAPNODECACHE, M_CACHE, &umap_node_hash);
88 * umap_findid is called by various routines in umap_vnodeops.c to
89 * find a user or group id in a map.
92 umap_findid(id, map, nentries)
99 /* Find uid entry in map */
101 while ((i<nentries) && ((map[i][0]) != id))
112 * umap_reverse_findid is called by umap_getattr() in umap_vnodeops.c to
113 * find a user or group id in a map, in reverse.
116 umap_reverse_findid(id, map, nentries)
123 /* Find uid entry in map */
125 while ((i<nentries) && ((map[i][1]) != id))
136 * Return alias for target vnode if already exists, else 0.
138 static struct vnode *
139 umap_node_find(mp, targetvp)
141 struct vnode *targetvp;
143 struct proc *p = curproc; /* XXX */
144 struct umap_node_hashhead *hd;
149 printf("umap_node_find(mp = %p, target = %p)\n",
150 (void *)mp, (void *)targetvp);
154 * Find hash base, and then search the (two-way) linked
155 * list looking for a umap_node structure which is referencing
156 * the target vnode. If found, the increment the umap_node
157 * reference count (but NOT the target vnode's VREF counter).
159 hd = UMAP_NHASH(targetvp);
161 for (a = hd->lh_first; a != 0; a = a->umap_hash.le_next) {
162 if (a->umap_lowervp == targetvp &&
163 a->umap_vnode->v_mount == mp) {
166 * We need vget for the VXLOCK
167 * stuff, but we don't want to lock
170 if (vget(vp, 0, p)) {
172 printf ("umap_node_find: vget failed.\n");
181 printf("umap_node_find(%p, %p): NOT found\n",
182 (void *)mp, (void *)targetvp);
189 * Make a new umap_node node.
190 * Vp is the alias vnode, lofsvp is the target vnode.
191 * Maintain a reference to (targetvp).
194 umap_node_alloc(mp, lowervp, vpp)
196 struct vnode *lowervp;
199 struct umap_node_hashhead *hd;
200 struct umap_node *xp;
201 struct vnode *othervp, *vp;
204 /* XXX This routine probably needs a node_alloc lock */
207 * Do the MALLOC before the getnewvnode since doing so afterward
208 * might cause a bogus v_data pointer to get dereferenced
209 * elsewhere if MALLOC should block.
211 MALLOC(xp, struct umap_node *, sizeof(struct umap_node),
214 error = getnewvnode(VT_UMAP, mp, umap_vnodeop_p, vpp);
221 vp->v_type = lowervp->v_type;
224 xp->umap_lowervp = lowervp;
226 * Before we insert our new node onto the hash chains,
227 * check to see if someone else has beaten us to it.
228 * (We could have slept in MALLOC.)
230 othervp = umap_node_find(mp, lowervp);
233 vp->v_type = VBAD; /* node is discarded */
234 vp->v_usecount = 0; /* XXX */
238 VREF(lowervp); /* Extra VREF will be vrele'd in umap_node_create */
239 hd = UMAP_NHASH(lowervp);
240 LIST_INSERT_HEAD(hd, xp, umap_hash);
246 * Try to find an existing umap_node vnode refering
247 * to it, otherwise make a new umap_node vnode which
248 * contains a reference to the target vnode.
251 umap_node_create(mp, targetvp, newvpp)
253 struct vnode *targetvp;
254 struct vnode **newvpp;
256 struct vnode *aliasvp;
258 aliasvp = umap_node_find(mp, targetvp);
261 * Take another reference to the alias vnode
264 vprint("umap_node_create: exists", aliasvp);
274 printf("umap_node_create: create new alias vnode\n");
277 * Make new vnode reference the umap_node.
279 error = umap_node_alloc(mp, targetvp, &aliasvp);
284 * aliasvp is already VREF'd by getnewvnode()
291 vprint("umap_node_create: alias", aliasvp);
292 vprint("umap_node_create: target", targetvp);
300 int umap_checkvp_barrier = 1;
302 umap_checkvp(vp, fil, lno)
307 struct umap_node *a = VTOUMAP(vp);
310 * Can't do this check because vop_reclaim runs
311 * with funny vop vector.
313 if (vp->v_op != umap_vnodeop_p) {
314 printf ("umap_checkvp: on non-umap-node\n");
315 while (umap_checkvp_barrier) /*WAIT*/ ;
316 panic("umap_checkvp");
319 if (a->umap_lowervp == NULL) {
320 /* Should never happen */
322 printf("vp = %p, ZERO ptr\n", (void *)vp);
323 for (p = (u_long *) a, i = 0; i < 8; i++)
324 printf(" %p", (void *)p[i]);
326 /* wait for debugger */
327 while (umap_checkvp_barrier) /*WAIT*/ ;
328 panic("umap_checkvp");
330 if (a->umap_lowervp->v_usecount < 1) {
332 printf("vp = %p, unref'ed lowervp\n", (void *)vp);
333 for (p = (u_long *) a, i = 0; i < 8; i++)
334 printf(" %p", (void *)p[i]);
336 /* wait for debugger */
337 while (umap_checkvp_barrier) /*WAIT*/ ;
338 panic ("umap with unref'ed lowervp");
341 printf("umap %x/%d -> %x/%d [%s, %d]\n",
342 a->umap_vnode, a->umap_vnode->v_usecount,
343 a->umap_lowervp, a->umap_lowervp->v_usecount,
346 return (a->umap_lowervp);
348 #endif /* DIAGNOSTIC */
350 /* umap_mapids maps all of the ids in a credential, both user and group. */
353 umap_mapids(v_mount, credp)
354 struct mount *v_mount;
364 /* Find uid entry in map */
366 uid = (uid_t) umap_findid(credp->cr_uid,
367 MOUNTTOUMAPMOUNT(v_mount)->info_mapdata,
368 MOUNTTOUMAPMOUNT(v_mount)->info_nentries);
373 credp->cr_uid = (uid_t) NOBODY;
376 /* cr_gid is the same as cr_groups[0] in 4BSD */
378 /* Find gid entry in map */
380 gid = (gid_t) umap_findid(credp->cr_gid,
381 MOUNTTOUMAPMOUNT(v_mount)->info_gmapdata,
382 MOUNTTOUMAPMOUNT(v_mount)->info_gnentries);
387 credp->cr_gid = NULLGROUP;
390 /* Now we must map each of the set of groups in the cr_groups
394 while (credp->cr_groups[i] != 0) {
395 gid = (gid_t) umap_findid(credp->cr_groups[i],
396 MOUNTTOUMAPMOUNT(v_mount)->info_gmapdata,
397 MOUNTTOUMAPMOUNT(v_mount)->info_gnentries);
400 credp->cr_groups[i++] = gid;
402 credp->cr_groups[i++] = NULLGROUP;