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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 1.13 2004/12/17 00:18:46 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) */
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 struct umap_node **umap_node_hashtbl;
64 static u_long umap_node_hash;
66 static u_long umap_findid (u_long id, u_long map[][2], int nentries);
67 static int umap_node_alloc (struct mount *mp, struct vnode *lowervp,
70 umap_node_find (struct mount *mp, struct vnode *targetvp);
73 * Initialise cache headers
76 umapfs_init(struct vfsconf *vfsp)
79 printf("umapfs_init\n"); /* printed during system boot */
82 while (umap_node_hash < desiredvnodes)
84 umap_node_hashtbl = malloc(sizeof(void *) * umap_node_hash, M_CACHE,
91 * umap_findid is called by various routines in umap_vnodeops.c to
92 * find a user or group id in a map.
95 umap_findid(u_long id, u_long map[][2], int nentries)
99 /* Find uid entry in map */
101 while ((i<nentries) && ((map[i][0]) != id))
111 * umap_reverse_findid is called by umap_getattr() in umap_vnodeops.c to
112 * find a user or group id in a map, in reverse.
115 umap_reverse_findid(u_long id, u_long map[][2], int nentries)
119 /* Find uid entry in map */
121 while ((i<nentries) && ((map[i][1]) != id))
131 * Return alias for target vnode if already exists, else 0.
133 static struct vnode *
134 umap_node_find(struct mount *mp, struct vnode *targetvp)
136 struct thread *td = curthread; /* XXX */
137 struct umap_node **xpp;
138 struct umap_node *xp;
142 printf("umap_node_find(mp = %p, target = %p)\n",
143 (void *)mp, (void *)targetvp);
147 * Find hash base, and then search the (two-way) linked
148 * list looking for a umap_node structure which is referencing
149 * the target vnode. If found, the increment the umap_node
150 * reference count (but NOT the target vnode's vref counter).
152 xpp = UMAP_NHASH(targetvp);
154 for (xp = *xpp; xp; xp = (void *)xp->umap_next) {
155 if (xp->umap_lowervp == targetvp &&
156 xp->umap_vnode->v_mount == mp) {
159 * We need vget for the VXLOCK
160 * stuff, but we don't want to lock
163 if (vget(vp, LK_EXCLUSIVE|LK_SLEEPFAIL, td)) {
165 printf ("umap_node_find: vget failed.\n");
174 printf("umap_node_find(%p, %p): NOT found\n",
175 (void *)mp, (void *)targetvp);
182 * Make a new umap_node node.
183 * Vp is the alias vnode, lofsvp is the target vnode.
184 * Maintain a reference to (targetvp).
187 umap_node_alloc(struct mount *mp, struct vnode *lowervp, struct vnode **vpp)
189 struct umap_node *xp;
190 struct umap_node **xpp;
191 struct vnode *othervp, *vp;
194 /* XXX This routine probably needs a node_alloc lock */
197 * Do the MALLOC before the getnewvnode since doing so afterward
198 * might cause a bogus v_data pointer to get dereferenced
199 * elsewhere if MALLOC should block.
201 MALLOC(xp, struct umap_node *, sizeof(struct umap_node),
204 error = getnewvnode(VT_UMAP, mp, vpp, 0, 0);
211 vp->v_type = lowervp->v_type;
214 xp->umap_lowervp = lowervp;
216 * Before we insert our new node onto the hash chains,
217 * check to see if someone else has beaten us to it.
218 * (We could have slept in MALLOC.)
220 othervp = umap_node_find(mp, lowervp);
223 vp->v_type = VBAD; /* node is discarded */
228 vref(lowervp); /* Extra vref will be vrele'd in umap_node_create */
229 xpp = UMAP_NHASH(lowervp);
230 xp->umap_next = (void *)*xpp;
236 umap_node_delete(struct umap_node *xp)
238 struct umap_node **xpp;
240 xpp = UMAP_NHASH(xp->umap_lowervp);
241 while (*xpp && *xpp != xp)
242 xpp = &(*xpp)->umap_next;
244 *xpp = (void *)xp->umap_next;
245 xp->umap_next = NULL;
249 * Try to find an existing umap_node vnode refering
250 * to it, otherwise make a new umap_node vnode which
251 * contains a reference to the target vnode.
254 umap_node_create(struct mount *mp, struct vnode *targetvp,
255 struct vnode **newvpp)
257 struct vnode *aliasvp;
259 aliasvp = umap_node_find(mp, targetvp);
262 * Take another reference to the alias vnode
265 vprint("umap_node_create: exists", aliasvp);
275 printf("umap_node_create: create new alias vnode\n");
278 * Make new vnode reference the umap_node.
280 error = umap_node_alloc(mp, targetvp, &aliasvp);
285 * aliasvp is already vref'd by getnewvnode()
292 vprint("umap_node_create: alias", aliasvp);
293 vprint("umap_node_create: target", targetvp);
301 int umap_checkvp_barrier = 1;
303 umap_checkvp(struct vnode *vp, char *fil, int lno)
305 struct umap_node *a = VTOUMAP(vp);
306 if (a->umap_lowervp == NULL) {
307 /* Should never happen */
309 printf("vp = %p, ZERO ptr\n", (void *)vp);
310 for (p = (u_long *) a, i = 0; i < 8; i++)
311 printf(" %p", (void *)p[i]);
313 /* wait for debugger */
314 while (umap_checkvp_barrier) /*WAIT*/ ;
315 panic("umap_checkvp");
317 if (a->umap_lowervp->v_usecount < 1) {
319 printf("vp = %p, unref'ed lowervp\n", (void *)vp);
320 for (p = (u_long *) a, i = 0; i < 8; i++)
321 printf(" %p", (void *)p[i]);
323 /* wait for debugger */
324 while (umap_checkvp_barrier) /*WAIT*/ ;
325 panic ("umap with unref'ed lowervp");
328 printf("umap %x/%d -> %x/%d [%s, %d]\n",
329 a->umap_vnode, a->umap_vnode->v_usecount,
330 a->umap_lowervp, a->umap_lowervp->v_usecount,
333 return (a->umap_lowervp);
335 #endif /* DIAGNOSTIC */
337 /* umap_mapids maps all of the ids in a credential, both user and group. */
340 umap_mapids(struct mount *v_mount, struct ucred *credp)
349 /* Find uid entry in map */
351 uid = (uid_t) umap_findid(credp->cr_uid,
352 MOUNTTOUMAPMOUNT(v_mount)->info_mapdata,
353 MOUNTTOUMAPMOUNT(v_mount)->info_nentries);
358 credp->cr_uid = (uid_t) NOBODY;
361 /* cr_gid is the same as cr_groups[0] in 4BSD */
363 /* Find gid entry in map */
365 gid = (gid_t) umap_findid(credp->cr_gid,
366 MOUNTTOUMAPMOUNT(v_mount)->info_gmapdata,
367 MOUNTTOUMAPMOUNT(v_mount)->info_gnentries);
372 credp->cr_gid = NULLGROUP;
375 /* Now we must map each of the set of groups in the cr_groups
379 while (credp->cr_groups[i] != 0) {
380 gid = (gid_t) umap_findid(credp->cr_groups[i],
381 MOUNTTOUMAPMOUNT(v_mount)->info_gmapdata,
382 MOUNTTOUMAPMOUNT(v_mount)->info_gnentries);
385 credp->cr_groups[i++] = gid;
387 credp->cr_groups[i++] = NULLGROUP;