Commit | Line | Data |
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b991bc2d JSP |
1 | /* |
2 | * Copyright (c) 1994 Jan-Simon Pendry | |
3 | * Copyright (c) 1994 | |
4 | * The Regents of the University of California. All rights reserved. | |
5 | * | |
6 | * This code is derived from software contributed to Berkeley by | |
7 | * Jan-Simon Pendry. | |
8 | * | |
9 | * %sccs.include.redist.c% | |
10 | * | |
8a9c17f6 | 11 | * @(#)union_subr.c 8.7 (Berkeley) %G% |
b991bc2d JSP |
12 | */ |
13 | ||
14 | #include <sys/param.h> | |
15 | #include <sys/systm.h> | |
16 | #include <sys/time.h> | |
17 | #include <sys/kernel.h> | |
18 | #include <sys/vnode.h> | |
19 | #include <sys/namei.h> | |
20 | #include <sys/malloc.h> | |
81be6ee0 | 21 | #include <sys/file.h> |
3b293975 | 22 | #include <sys/filedesc.h> |
58572fc0 | 23 | #include <sys/queue.h> |
c93d29a8 | 24 | #include <sys/mount.h> |
8a9c17f6 | 25 | #include <vm/vm.h> /* for vnode_pager_setsize */ |
2e1ae99e | 26 | #include <miscfs/union/union.h> |
b991bc2d | 27 | |
79f80c71 JSP |
28 | #ifdef DIAGNOSTIC |
29 | #include <sys/proc.h> | |
30 | #endif | |
31 | ||
58572fc0 JSP |
32 | /* must be power of two, otherwise change UNION_HASH() */ |
33 | #define NHASH 32 | |
34 | ||
35 | /* unsigned int ... */ | |
36 | #define UNION_HASH(u, l) \ | |
37 | (((((unsigned long) (u)) + ((unsigned long) l)) >> 8) & (NHASH-1)) | |
38 | ||
39 | static LIST_HEAD(unhead, union_node) unhead[NHASH]; | |
40 | static int unvplock[NHASH]; | |
b991bc2d JSP |
41 | |
42 | int | |
43 | union_init() | |
44 | { | |
58572fc0 JSP |
45 | int i; |
46 | ||
47 | for (i = 0; i < NHASH; i++) | |
48 | LIST_INIT(&unhead[i]); | |
49 | bzero((caddr_t) unvplock, sizeof(unvplock)); | |
50 | } | |
51 | ||
52 | static int | |
53 | union_list_lock(ix) | |
54 | int ix; | |
55 | { | |
56 | ||
57 | if (unvplock[ix] & UN_LOCKED) { | |
58 | unvplock[ix] |= UN_WANT; | |
59 | sleep((caddr_t) &unvplock[ix], PINOD); | |
60 | return (1); | |
61 | } | |
b991bc2d | 62 | |
58572fc0 JSP |
63 | unvplock[ix] |= UN_LOCKED; |
64 | ||
65 | return (0); | |
b991bc2d JSP |
66 | } |
67 | ||
e2a2f3a7 | 68 | static void |
58572fc0 JSP |
69 | union_list_unlock(ix) |
70 | int ix; | |
71 | { | |
72 | ||
73 | unvplock[ix] &= ~UN_LOCKED; | |
74 | ||
75 | if (unvplock[ix] & UN_WANT) { | |
76 | unvplock[ix] &= ~UN_WANT; | |
77 | wakeup((caddr_t) &unvplock[ix]); | |
78 | } | |
79 | } | |
80 | ||
81 | void | |
82 | union_updatevp(un, uppervp, lowervp) | |
e2a2f3a7 | 83 | struct union_node *un; |
58572fc0 JSP |
84 | struct vnode *uppervp; |
85 | struct vnode *lowervp; | |
e2a2f3a7 | 86 | { |
58572fc0 JSP |
87 | int ohash = UNION_HASH(un->un_uppervp, un->un_lowervp); |
88 | int nhash = UNION_HASH(uppervp, lowervp); | |
b5b5f291 | 89 | int docache = (lowervp != NULLVP || uppervp != NULLVP); |
e2a2f3a7 | 90 | |
b5b5f291 JSP |
91 | /* |
92 | * Ensure locking is ordered from lower to higher | |
93 | * to avoid deadlocks. | |
94 | */ | |
95 | if (nhash < ohash) { | |
96 | int t = ohash; | |
97 | ohash = nhash; | |
98 | nhash = t; | |
99 | } | |
58572fc0 | 100 | |
b5b5f291 | 101 | if (ohash != nhash) |
58572fc0 JSP |
102 | while (union_list_lock(ohash)) |
103 | continue; | |
104 | ||
b5b5f291 JSP |
105 | while (union_list_lock(nhash)) |
106 | continue; | |
58572fc0 | 107 | |
b5b5f291 JSP |
108 | if (ohash != nhash || !docache) { |
109 | if (un->un_flags & UN_CACHED) { | |
110 | LIST_REMOVE(un, un_cache); | |
111 | un->un_flags &= ~UN_CACHED; | |
112 | } | |
58572fc0 JSP |
113 | } |
114 | ||
b5b5f291 JSP |
115 | if (ohash != nhash) |
116 | union_list_unlock(ohash); | |
117 | ||
58572fc0 JSP |
118 | if (un->un_lowervp != lowervp) { |
119 | if (un->un_lowervp) { | |
120 | vrele(un->un_lowervp); | |
121 | if (un->un_path) { | |
122 | free(un->un_path, M_TEMP); | |
123 | un->un_path = 0; | |
124 | } | |
125 | if (un->un_dirvp) { | |
126 | vrele(un->un_dirvp); | |
127 | un->un_dirvp = NULLVP; | |
128 | } | |
e2a2f3a7 | 129 | } |
58572fc0 | 130 | un->un_lowervp = lowervp; |
8a9c17f6 | 131 | un->un_lowersz = VNOVAL; |
58572fc0 JSP |
132 | } |
133 | ||
134 | if (un->un_uppervp != uppervp) { | |
135 | if (un->un_uppervp) | |
136 | vrele(un->un_uppervp); | |
137 | ||
138 | un->un_uppervp = uppervp; | |
8a9c17f6 | 139 | un->un_uppersz = VNOVAL; |
e2a2f3a7 | 140 | } |
58572fc0 | 141 | |
b5b5f291 | 142 | if (docache && (ohash != nhash)) { |
58572fc0 | 143 | LIST_INSERT_HEAD(&unhead[nhash], un, un_cache); |
b5b5f291 JSP |
144 | un->un_flags |= UN_CACHED; |
145 | } | |
58572fc0 JSP |
146 | |
147 | union_list_unlock(nhash); | |
148 | } | |
149 | ||
150 | void | |
151 | union_newlower(un, lowervp) | |
152 | struct union_node *un; | |
153 | struct vnode *lowervp; | |
154 | { | |
155 | ||
156 | union_updatevp(un, un->un_uppervp, lowervp); | |
157 | } | |
158 | ||
159 | void | |
160 | union_newupper(un, uppervp) | |
161 | struct union_node *un; | |
162 | struct vnode *uppervp; | |
163 | { | |
164 | ||
165 | union_updatevp(un, uppervp, un->un_lowervp); | |
e2a2f3a7 JSP |
166 | } |
167 | ||
8a9c17f6 JSP |
168 | /* |
169 | * Keep track of size changes in the underlying vnodes. | |
170 | * If the size changes, then callback to the vm layer | |
171 | * giving priority to the upper layer size. | |
172 | */ | |
173 | void | |
174 | union_newsize(vp, uppersz, lowersz) | |
175 | struct vnode *vp; | |
176 | off_t uppersz, lowersz; | |
177 | { | |
178 | struct union_node *un; | |
179 | off_t sz; | |
180 | ||
181 | /* only interested in regular files */ | |
182 | if (vp->v_type != VREG) | |
183 | return; | |
184 | ||
185 | un = VTOUNION(vp); | |
186 | sz = VNOVAL; | |
187 | ||
188 | if ((uppersz != VNOVAL) && (un->un_uppersz != uppersz)) { | |
189 | un->un_uppersz = uppersz; | |
190 | if (sz == VNOVAL) | |
191 | sz = un->un_uppersz; | |
192 | } | |
193 | ||
194 | if ((lowersz != VNOVAL) && (un->un_lowersz != lowersz)) { | |
195 | un->un_lowersz = lowersz; | |
196 | if (sz == VNOVAL) | |
197 | sz = un->un_lowersz; | |
198 | } | |
199 | ||
200 | if (sz != VNOVAL) { | |
201 | #ifdef UNION_DIAGNOSTIC | |
202 | printf("union: %s size now %ld\n", | |
203 | uppersz != VNOVAL ? "upper" : "lower", (long) sz); | |
204 | #endif | |
205 | vnode_pager_setsize(vp, sz); | |
206 | } | |
207 | } | |
208 | ||
b991bc2d JSP |
209 | /* |
210 | * allocate a union_node/vnode pair. the vnode is | |
01dac67e JSP |
211 | * referenced and locked. the new vnode is returned |
212 | * via (vpp). (mp) is the mountpoint of the union filesystem, | |
213 | * (dvp) is the parent directory where the upper layer object | |
214 | * should exist (but doesn't) and (cnp) is the componentname | |
215 | * information which is partially copied to allow the upper | |
216 | * layer object to be created at a later time. (uppervp) | |
217 | * and (lowervp) reference the upper and lower layer objects | |
218 | * being mapped. either, but not both, can be nil. | |
e2a2f3a7 | 219 | * if supplied, (uppervp) is locked. |
3b293975 JSP |
220 | * the reference is either maintained in the new union_node |
221 | * object which is allocated, or they are vrele'd. | |
b991bc2d JSP |
222 | * |
223 | * all union_nodes are maintained on a singly-linked | |
224 | * list. new nodes are only allocated when they cannot | |
225 | * be found on this list. entries on the list are | |
226 | * removed when the vfs reclaim entry is called. | |
227 | * | |
228 | * a single lock is kept for the entire list. this is | |
229 | * needed because the getnewvnode() function can block | |
230 | * waiting for a vnode to become free, in which case there | |
231 | * may be more than one process trying to get the same | |
232 | * vnode. this lock is only taken if we are going to | |
233 | * call getnewvnode, since the kernel itself is single-threaded. | |
234 | * | |
235 | * if an entry is found on the list, then call vget() to | |
236 | * take a reference. this is done because there may be | |
237 | * zero references to it and so it needs to removed from | |
238 | * the vnode free list. | |
239 | */ | |
240 | int | |
79f80c71 | 241 | union_allocvp(vpp, mp, undvp, dvp, cnp, uppervp, lowervp) |
b991bc2d JSP |
242 | struct vnode **vpp; |
243 | struct mount *mp; | |
79f80c71 | 244 | struct vnode *undvp; |
b991bc2d JSP |
245 | struct vnode *dvp; /* may be null */ |
246 | struct componentname *cnp; /* may be null */ | |
247 | struct vnode *uppervp; /* may be null */ | |
248 | struct vnode *lowervp; /* may be null */ | |
249 | { | |
250 | int error; | |
251 | struct union_node *un; | |
252 | struct union_node **pp; | |
58572fc0 | 253 | struct vnode *xlowervp = NULLVP; |
c93d29a8 | 254 | struct union_mount *um = MOUNTTOUNIONMOUNT(mp); |
58572fc0 | 255 | int hash; |
c93d29a8 | 256 | int vflag; |
58572fc0 | 257 | int try; |
01dac67e | 258 | |
58572fc0 | 259 | if (uppervp == NULLVP && lowervp == NULLVP) |
01dac67e JSP |
260 | panic("union: unidentifiable allocation"); |
261 | ||
262 | if (uppervp && lowervp && (uppervp->v_type != lowervp->v_type)) { | |
263 | xlowervp = lowervp; | |
58572fc0 | 264 | lowervp = NULLVP; |
01dac67e | 265 | } |
b991bc2d | 266 | |
c93d29a8 JSP |
267 | /* detect the root vnode (and aliases) */ |
268 | vflag = 0; | |
269 | if ((uppervp == um->um_uppervp) && | |
270 | ((lowervp == NULLVP) || lowervp == um->um_lowervp)) { | |
271 | if (lowervp == NULLVP) { | |
272 | lowervp = um->um_lowervp; | |
273 | VREF(lowervp); | |
274 | } | |
275 | vflag = VROOT; | |
276 | } | |
277 | ||
b991bc2d | 278 | loop: |
58572fc0 JSP |
279 | for (try = 0; try < 3; try++) { |
280 | switch (try) { | |
281 | case 0: | |
282 | if (lowervp == NULLVP) | |
283 | continue; | |
284 | hash = UNION_HASH(uppervp, lowervp); | |
e2a2f3a7 | 285 | break; |
58572fc0 JSP |
286 | |
287 | case 1: | |
288 | if (uppervp == NULLVP) | |
289 | continue; | |
290 | hash = UNION_HASH(uppervp, NULLVP); | |
291 | break; | |
292 | ||
293 | case 2: | |
294 | if (lowervp == NULLVP) | |
295 | continue; | |
296 | hash = UNION_HASH(NULLVP, lowervp); | |
297 | break; | |
298 | } | |
299 | ||
300 | while (union_list_lock(hash)) | |
301 | continue; | |
302 | ||
303 | for (un = unhead[hash].lh_first; un != 0; | |
304 | un = un->un_cache.le_next) { | |
305 | if ((un->un_lowervp == lowervp || | |
306 | un->un_lowervp == NULLVP) && | |
307 | (un->un_uppervp == uppervp || | |
308 | un->un_uppervp == NULLVP) && | |
309 | (UNIONTOV(un)->v_mount == mp)) { | |
310 | if (vget(UNIONTOV(un), 0)) { | |
311 | union_list_unlock(hash); | |
312 | goto loop; | |
313 | } | |
314 | break; | |
315 | } | |
e2a2f3a7 | 316 | } |
58572fc0 JSP |
317 | |
318 | union_list_unlock(hash); | |
319 | ||
320 | if (un) | |
321 | break; | |
e2a2f3a7 | 322 | } |
ed5969c8 | 323 | |
e2a2f3a7 JSP |
324 | if (un) { |
325 | /* | |
326 | * Obtain a lock on the union_node. | |
327 | * uppervp is locked, though un->un_uppervp | |
328 | * may not be. this doesn't break the locking | |
329 | * hierarchy since in the case that un->un_uppervp | |
330 | * is not yet locked it will be vrele'd and replaced | |
331 | * with uppervp. | |
332 | */ | |
333 | ||
334 | if ((dvp != NULLVP) && (uppervp == dvp)) { | |
ed5969c8 | 335 | /* |
e2a2f3a7 JSP |
336 | * Access ``.'', so (un) will already |
337 | * be locked. Since this process has | |
338 | * the lock on (uppervp) no other | |
339 | * process can hold the lock on (un). | |
ed5969c8 | 340 | */ |
e2a2f3a7 JSP |
341 | #ifdef DIAGNOSTIC |
342 | if ((un->un_flags & UN_LOCKED) == 0) | |
343 | panic("union: . not locked"); | |
344 | else if (curproc && un->un_pid != curproc->p_pid && | |
345 | un->un_pid > -1 && curproc->p_pid > -1) | |
346 | panic("union: allocvp not lock owner"); | |
347 | #endif | |
348 | } else { | |
349 | if (un->un_flags & UN_LOCKED) { | |
350 | vrele(UNIONTOV(un)); | |
351 | un->un_flags |= UN_WANT; | |
352 | sleep((caddr_t) &un->un_flags, PINOD); | |
353 | goto loop; | |
79f80c71 | 354 | } |
e2a2f3a7 | 355 | un->un_flags |= UN_LOCKED; |
ed5969c8 | 356 | |
e2a2f3a7 JSP |
357 | #ifdef DIAGNOSTIC |
358 | if (curproc) | |
359 | un->un_pid = curproc->p_pid; | |
360 | else | |
361 | un->un_pid = -1; | |
362 | #endif | |
363 | } | |
364 | ||
365 | /* | |
366 | * At this point, the union_node is locked, | |
367 | * un->un_uppervp may not be locked, and uppervp | |
368 | * is locked or nil. | |
369 | */ | |
370 | ||
371 | /* | |
372 | * Save information about the upper layer. | |
373 | */ | |
374 | if (uppervp != un->un_uppervp) { | |
58572fc0 | 375 | union_newupper(un, uppervp); |
e2a2f3a7 JSP |
376 | } else if (uppervp) { |
377 | vrele(uppervp); | |
378 | } | |
379 | ||
380 | if (un->un_uppervp) { | |
381 | un->un_flags |= UN_ULOCK; | |
382 | un->un_flags &= ~UN_KLOCK; | |
383 | } | |
384 | ||
385 | /* | |
386 | * Save information about the lower layer. | |
387 | * This needs to keep track of pathname | |
388 | * and directory information which union_vn_create | |
389 | * might need. | |
390 | */ | |
391 | if (lowervp != un->un_lowervp) { | |
58572fc0 | 392 | union_newlower(un, lowervp); |
e2a2f3a7 JSP |
393 | if (cnp && (lowervp != NULLVP) && |
394 | (lowervp->v_type == VREG)) { | |
395 | un->un_hash = cnp->cn_hash; | |
396 | un->un_path = malloc(cnp->cn_namelen+1, | |
397 | M_TEMP, M_WAITOK); | |
398 | bcopy(cnp->cn_nameptr, un->un_path, | |
399 | cnp->cn_namelen); | |
400 | un->un_path[cnp->cn_namelen] = '\0'; | |
401 | VREF(dvp); | |
402 | un->un_dirvp = dvp; | |
79f80c71 | 403 | } |
e2a2f3a7 JSP |
404 | } else if (lowervp) { |
405 | vrele(lowervp); | |
b991bc2d | 406 | } |
e2a2f3a7 JSP |
407 | *vpp = UNIONTOV(un); |
408 | return (0); | |
b991bc2d JSP |
409 | } |
410 | ||
411 | /* | |
412 | * otherwise lock the vp list while we call getnewvnode | |
413 | * since that can block. | |
414 | */ | |
58572fc0 JSP |
415 | hash = UNION_HASH(uppervp, lowervp); |
416 | ||
417 | if (union_list_lock(hash)) | |
b991bc2d | 418 | goto loop; |
b991bc2d JSP |
419 | |
420 | error = getnewvnode(VT_UNION, mp, union_vnodeop_p, vpp); | |
e2a2f3a7 JSP |
421 | if (error) { |
422 | if (uppervp) { | |
423 | if (dvp == uppervp) | |
424 | vrele(uppervp); | |
425 | else | |
426 | vput(uppervp); | |
427 | } | |
428 | if (lowervp) | |
429 | vrele(lowervp); | |
430 | ||
b991bc2d | 431 | goto out; |
e2a2f3a7 | 432 | } |
b991bc2d JSP |
433 | |
434 | MALLOC((*vpp)->v_data, void *, sizeof(struct union_node), | |
435 | M_TEMP, M_WAITOK); | |
436 | ||
c93d29a8 | 437 | (*vpp)->v_flag |= vflag; |
01dac67e JSP |
438 | if (uppervp) |
439 | (*vpp)->v_type = uppervp->v_type; | |
440 | else | |
441 | (*vpp)->v_type = lowervp->v_type; | |
b991bc2d | 442 | un = VTOUNION(*vpp); |
79f80c71 | 443 | un->un_vnode = *vpp; |
b991bc2d | 444 | un->un_uppervp = uppervp; |
8a9c17f6 | 445 | un->un_uppersz = VNOVAL; |
b991bc2d | 446 | un->un_lowervp = lowervp; |
8a9c17f6 | 447 | un->un_lowersz = VNOVAL; |
15a86f7e | 448 | un->un_openl = 0; |
e2a2f3a7 JSP |
449 | un->un_flags = UN_LOCKED; |
450 | if (un->un_uppervp) | |
451 | un->un_flags |= UN_ULOCK; | |
452 | #ifdef DIAGNOSTIC | |
453 | if (curproc) | |
454 | un->un_pid = curproc->p_pid; | |
455 | else | |
456 | un->un_pid = -1; | |
457 | #endif | |
ed5969c8 JSP |
458 | if (cnp && (lowervp != NULLVP) && (lowervp->v_type == VREG)) { |
459 | un->un_hash = cnp->cn_hash; | |
b991bc2d JSP |
460 | un->un_path = malloc(cnp->cn_namelen+1, M_TEMP, M_WAITOK); |
461 | bcopy(cnp->cn_nameptr, un->un_path, cnp->cn_namelen); | |
462 | un->un_path[cnp->cn_namelen] = '\0'; | |
01dac67e JSP |
463 | VREF(dvp); |
464 | un->un_dirvp = dvp; | |
b991bc2d | 465 | } else { |
ed5969c8 | 466 | un->un_hash = 0; |
b991bc2d | 467 | un->un_path = 0; |
01dac67e | 468 | un->un_dirvp = 0; |
b991bc2d JSP |
469 | } |
470 | ||
58572fc0 | 471 | LIST_INSERT_HEAD(&unhead[hash], un, un_cache); |
b5b5f291 | 472 | un->un_flags |= UN_CACHED; |
b991bc2d | 473 | |
01dac67e JSP |
474 | if (xlowervp) |
475 | vrele(xlowervp); | |
476 | ||
b991bc2d | 477 | out: |
58572fc0 | 478 | union_list_unlock(hash); |
b991bc2d | 479 | |
b991bc2d JSP |
480 | return (error); |
481 | } | |
482 | ||
483 | int | |
484 | union_freevp(vp) | |
485 | struct vnode *vp; | |
486 | { | |
b991bc2d JSP |
487 | struct union_node *un = VTOUNION(vp); |
488 | ||
b5b5f291 JSP |
489 | if (un->un_flags & UN_CACHED) { |
490 | LIST_REMOVE(un, un_cache); | |
491 | un->un_flags &= ~UN_CACHED; | |
492 | } | |
58572fc0 | 493 | |
b5b5f291 | 494 | if (un->un_uppervp != NULLVP) |
58572fc0 | 495 | vrele(un->un_uppervp); |
b5b5f291 | 496 | if (un->un_lowervp != NULLVP) |
58572fc0 | 497 | vrele(un->un_lowervp); |
b5b5f291 | 498 | if (un->un_dirvp != NULLVP) |
58572fc0 JSP |
499 | vrele(un->un_dirvp); |
500 | if (un->un_path) | |
501 | free(un->un_path, M_TEMP); | |
b991bc2d | 502 | |
b991bc2d JSP |
503 | FREE(vp->v_data, M_TEMP); |
504 | vp->v_data = 0; | |
58572fc0 | 505 | |
b991bc2d JSP |
506 | return (0); |
507 | } | |
81be6ee0 JSP |
508 | |
509 | /* | |
510 | * copyfile. copy the vnode (fvp) to the vnode (tvp) | |
511 | * using a sequence of reads and writes. both (fvp) | |
512 | * and (tvp) are locked on entry and exit. | |
513 | */ | |
514 | int | |
515 | union_copyfile(p, cred, fvp, tvp) | |
516 | struct proc *p; | |
517 | struct ucred *cred; | |
518 | struct vnode *fvp; | |
519 | struct vnode *tvp; | |
520 | { | |
521 | char *buf; | |
522 | struct uio uio; | |
523 | struct iovec iov; | |
524 | int error = 0; | |
525 | ||
526 | /* | |
527 | * strategy: | |
528 | * allocate a buffer of size MAXBSIZE. | |
529 | * loop doing reads and writes, keeping track | |
530 | * of the current uio offset. | |
531 | * give up at the first sign of trouble. | |
532 | */ | |
533 | ||
534 | uio.uio_procp = p; | |
535 | uio.uio_segflg = UIO_SYSSPACE; | |
536 | uio.uio_offset = 0; | |
537 | ||
538 | VOP_UNLOCK(fvp); /* XXX */ | |
539 | LEASE_CHECK(fvp, p, cred, LEASE_READ); | |
540 | VOP_LOCK(fvp); /* XXX */ | |
541 | VOP_UNLOCK(tvp); /* XXX */ | |
542 | LEASE_CHECK(tvp, p, cred, LEASE_WRITE); | |
543 | VOP_LOCK(tvp); /* XXX */ | |
544 | ||
545 | buf = malloc(MAXBSIZE, M_TEMP, M_WAITOK); | |
546 | ||
547 | /* ugly loop follows... */ | |
548 | do { | |
549 | off_t offset = uio.uio_offset; | |
550 | ||
551 | uio.uio_iov = &iov; | |
552 | uio.uio_iovcnt = 1; | |
553 | iov.iov_base = buf; | |
554 | iov.iov_len = MAXBSIZE; | |
555 | uio.uio_resid = iov.iov_len; | |
556 | uio.uio_rw = UIO_READ; | |
557 | error = VOP_READ(fvp, &uio, 0, cred); | |
558 | ||
559 | if (error == 0) { | |
560 | uio.uio_iov = &iov; | |
561 | uio.uio_iovcnt = 1; | |
562 | iov.iov_base = buf; | |
563 | iov.iov_len = MAXBSIZE - uio.uio_resid; | |
564 | uio.uio_offset = offset; | |
565 | uio.uio_rw = UIO_WRITE; | |
566 | uio.uio_resid = iov.iov_len; | |
567 | ||
568 | if (uio.uio_resid == 0) | |
569 | break; | |
570 | ||
571 | do { | |
572 | error = VOP_WRITE(tvp, &uio, 0, cred); | |
573 | } while ((uio.uio_resid > 0) && (error == 0)); | |
574 | } | |
575 | ||
576 | } while (error == 0); | |
577 | ||
578 | free(buf, M_TEMP); | |
579 | return (error); | |
580 | } | |
581 | ||
3b293975 JSP |
582 | /* |
583 | * Create a shadow directory in the upper layer. | |
584 | * The new vnode is returned locked. | |
585 | * | |
586 | * (um) points to the union mount structure for access to the | |
587 | * the mounting process's credentials. | |
588 | * (dvp) is the directory in which to create the shadow directory. | |
589 | * it is unlocked on entry and exit. | |
590 | * (cnp) is the componentname to be created. | |
591 | * (vpp) is the returned newly created shadow directory, which | |
592 | * is returned locked. | |
593 | */ | |
594 | int | |
595 | union_mkshadow(um, dvp, cnp, vpp) | |
596 | struct union_mount *um; | |
597 | struct vnode *dvp; | |
598 | struct componentname *cnp; | |
599 | struct vnode **vpp; | |
600 | { | |
601 | int error; | |
602 | struct vattr va; | |
603 | struct proc *p = cnp->cn_proc; | |
604 | struct componentname cn; | |
605 | ||
606 | /* | |
607 | * policy: when creating the shadow directory in the | |
692a90df JSP |
608 | * upper layer, create it owned by the user who did |
609 | * the mount, group from parent directory, and mode | |
610 | * 777 modified by umask (ie mostly identical to the | |
611 | * mkdir syscall). (jsp, kb) | |
3b293975 JSP |
612 | */ |
613 | ||
614 | /* | |
615 | * A new componentname structure must be faked up because | |
616 | * there is no way to know where the upper level cnp came | |
617 | * from or what it is being used for. This must duplicate | |
618 | * some of the work done by NDINIT, some of the work done | |
619 | * by namei, some of the work done by lookup and some of | |
620 | * the work done by VOP_LOOKUP when given a CREATE flag. | |
621 | * Conclusion: Horrible. | |
622 | * | |
623 | * The pathname buffer will be FREEed by VOP_MKDIR. | |
624 | */ | |
625 | cn.cn_pnbuf = malloc(cnp->cn_namelen+1, M_NAMEI, M_WAITOK); | |
ed5969c8 JSP |
626 | bcopy(cnp->cn_nameptr, cn.cn_pnbuf, cnp->cn_namelen); |
627 | cn.cn_pnbuf[cnp->cn_namelen] = '\0'; | |
3b293975 JSP |
628 | |
629 | cn.cn_nameiop = CREATE; | |
bf006388 | 630 | cn.cn_flags = (LOCKPARENT|HASBUF|SAVENAME|SAVESTART|ISLASTCN); |
3b293975 | 631 | cn.cn_proc = cnp->cn_proc; |
c1b204a8 JSP |
632 | if (um->um_op == UNMNT_ABOVE) |
633 | cn.cn_cred = cnp->cn_cred; | |
634 | else | |
635 | cn.cn_cred = um->um_cred; | |
3b293975 JSP |
636 | cn.cn_nameptr = cn.cn_pnbuf; |
637 | cn.cn_namelen = cnp->cn_namelen; | |
638 | cn.cn_hash = cnp->cn_hash; | |
639 | cn.cn_consume = cnp->cn_consume; | |
640 | ||
ed5969c8 | 641 | VREF(dvp); |
3b293975 JSP |
642 | if (error = relookup(dvp, vpp, &cn)) |
643 | return (error); | |
ed5969c8 | 644 | vrele(dvp); |
3b293975 JSP |
645 | |
646 | if (*vpp) { | |
647 | VOP_ABORTOP(dvp, &cn); | |
648 | VOP_UNLOCK(dvp); | |
649 | vrele(*vpp); | |
650 | *vpp = NULLVP; | |
651 | return (EEXIST); | |
652 | } | |
653 | ||
654 | VATTR_NULL(&va); | |
655 | va.va_type = VDIR; | |
692a90df | 656 | va.va_mode = um->um_cmode; |
3b293975 JSP |
657 | |
658 | /* LEASE_CHECK: dvp is locked */ | |
659 | LEASE_CHECK(dvp, p, p->p_ucred, LEASE_WRITE); | |
660 | ||
3b293975 JSP |
661 | error = VOP_MKDIR(dvp, vpp, &cn, &va); |
662 | return (error); | |
663 | } | |
664 | ||
81be6ee0 JSP |
665 | /* |
666 | * union_vn_create: creates and opens a new shadow file | |
667 | * on the upper union layer. this function is similar | |
668 | * in spirit to calling vn_open but it avoids calling namei(). | |
669 | * the problem with calling namei is that a) it locks too many | |
670 | * things, and b) it doesn't start at the "right" directory, | |
671 | * whereas relookup is told where to start. | |
672 | */ | |
673 | int | |
3b293975 | 674 | union_vn_create(vpp, un, p) |
81be6ee0 JSP |
675 | struct vnode **vpp; |
676 | struct union_node *un; | |
81be6ee0 JSP |
677 | struct proc *p; |
678 | { | |
679 | struct vnode *vp; | |
680 | struct ucred *cred = p->p_ucred; | |
681 | struct vattr vat; | |
682 | struct vattr *vap = &vat; | |
683 | int fmode = FFLAGS(O_WRONLY|O_CREAT|O_TRUNC|O_EXCL); | |
684 | int error; | |
ed5969c8 | 685 | int cmode = UN_FILEMODE & ~p->p_fd->fd_cmask; |
81be6ee0 JSP |
686 | char *cp; |
687 | struct componentname cn; | |
688 | ||
689 | *vpp = NULLVP; | |
690 | ||
692a90df JSP |
691 | /* |
692 | * Build a new componentname structure (for the same | |
693 | * reasons outlines in union_mkshadow). | |
694 | * The difference here is that the file is owned by | |
695 | * the current user, rather than by the person who | |
696 | * did the mount, since the current user needs to be | |
697 | * able to write the file (that's why it is being | |
698 | * copied in the first place). | |
699 | */ | |
81be6ee0 JSP |
700 | cn.cn_namelen = strlen(un->un_path); |
701 | cn.cn_pnbuf = (caddr_t) malloc(cn.cn_namelen, M_NAMEI, M_WAITOK); | |
702 | bcopy(un->un_path, cn.cn_pnbuf, cn.cn_namelen+1); | |
703 | cn.cn_nameiop = CREATE; | |
bf006388 | 704 | cn.cn_flags = (LOCKPARENT|HASBUF|SAVENAME|SAVESTART|ISLASTCN); |
81be6ee0 JSP |
705 | cn.cn_proc = p; |
706 | cn.cn_cred = p->p_ucred; | |
707 | cn.cn_nameptr = cn.cn_pnbuf; | |
ed5969c8 | 708 | cn.cn_hash = un->un_hash; |
81be6ee0 JSP |
709 | cn.cn_consume = 0; |
710 | ||
ed5969c8 | 711 | VREF(un->un_dirvp); |
81be6ee0 JSP |
712 | if (error = relookup(un->un_dirvp, &vp, &cn)) |
713 | return (error); | |
ed5969c8 JSP |
714 | vrele(un->un_dirvp); |
715 | ||
bf006388 | 716 | if (vp) { |
81be6ee0 JSP |
717 | VOP_ABORTOP(un->un_dirvp, &cn); |
718 | if (un->un_dirvp == vp) | |
719 | vrele(un->un_dirvp); | |
720 | else | |
bf006388 JSP |
721 | vput(un->un_dirvp); |
722 | vrele(vp); | |
723 | return (EEXIST); | |
81be6ee0 JSP |
724 | } |
725 | ||
bf006388 JSP |
726 | /* |
727 | * Good - there was no race to create the file | |
728 | * so go ahead and create it. The permissions | |
729 | * on the file will be 0666 modified by the | |
730 | * current user's umask. Access to the file, while | |
731 | * it is unioned, will require access to the top *and* | |
732 | * bottom files. Access when not unioned will simply | |
733 | * require access to the top-level file. | |
734 | * TODO: confirm choice of access permissions. | |
735 | */ | |
81be6ee0 | 736 | VATTR_NULL(vap); |
bf006388 JSP |
737 | vap->va_type = VREG; |
738 | vap->va_mode = cmode; | |
739 | LEASE_CHECK(un->un_dirvp, p, cred, LEASE_WRITE); | |
740 | if (error = VOP_CREATE(un->un_dirvp, &vp, &cn, vap)) | |
741 | return (error); | |
81be6ee0 | 742 | |
bf006388 JSP |
743 | if (error = VOP_OPEN(vp, fmode, cred, p)) { |
744 | vput(vp); | |
745 | return (error); | |
746 | } | |
81be6ee0 JSP |
747 | |
748 | vp->v_writecount++; | |
749 | *vpp = vp; | |
750 | return (0); | |
81be6ee0 | 751 | } |
ed5969c8 JSP |
752 | |
753 | int | |
15a86f7e | 754 | union_vn_close(vp, fmode, cred, p) |
ed5969c8 JSP |
755 | struct vnode *vp; |
756 | int fmode; | |
15a86f7e JSP |
757 | struct ucred *cred; |
758 | struct proc *p; | |
ed5969c8 JSP |
759 | { |
760 | if (fmode & FWRITE) | |
761 | --vp->v_writecount; | |
762 | return (VOP_CLOSE(vp, fmode)); | |
763 | } | |
764 | ||
765 | void | |
766 | union_removed_upper(un) | |
767 | struct union_node *un; | |
768 | { | |
e2a2f3a7 JSP |
769 | if (un->un_flags & UN_ULOCK) { |
770 | un->un_flags &= ~UN_ULOCK; | |
58572fc0 | 771 | VOP_UNLOCK(un->un_uppervp); |
e2a2f3a7 | 772 | } |
58572fc0 JSP |
773 | |
774 | union_newupper(un, NULLVP); | |
ed5969c8 | 775 | } |
15a86f7e JSP |
776 | |
777 | struct vnode * | |
778 | union_lowervp(vp) | |
779 | struct vnode *vp; | |
780 | { | |
781 | struct union_node *un = VTOUNION(vp); | |
782 | ||
783 | if (un->un_lowervp && (vp->v_type == un->un_lowervp->v_type)) { | |
784 | if (vget(un->un_lowervp, 0)) | |
785 | return (NULLVP); | |
786 | } | |
787 | ||
788 | return (un->un_lowervp); | |
789 | } |