vfs_trans.c revision 1.37 1 1.37 hannken /* $NetBSD: vfs_trans.c,v 1.37 2017/02/23 11:23:22 hannken Exp $ */
2 1.1 hannken
3 1.1 hannken /*-
4 1.1 hannken * Copyright (c) 2007 The NetBSD Foundation, Inc.
5 1.1 hannken * All rights reserved.
6 1.1 hannken *
7 1.1 hannken * This code is derived from software contributed to The NetBSD Foundation
8 1.1 hannken * by Juergen Hannken-Illjes.
9 1.1 hannken *
10 1.1 hannken * Redistribution and use in source and binary forms, with or without
11 1.1 hannken * modification, are permitted provided that the following conditions
12 1.1 hannken * are met:
13 1.1 hannken * 1. Redistributions of source code must retain the above copyright
14 1.1 hannken * notice, this list of conditions and the following disclaimer.
15 1.1 hannken * 2. Redistributions in binary form must reproduce the above copyright
16 1.1 hannken * notice, this list of conditions and the following disclaimer in the
17 1.1 hannken * documentation and/or other materials provided with the distribution.
18 1.1 hannken *
19 1.1 hannken * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 1.1 hannken * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 1.1 hannken * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 1.1 hannken * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 1.1 hannken * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 1.1 hannken * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 1.1 hannken * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 1.1 hannken * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 1.1 hannken * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 1.1 hannken * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 1.1 hannken * POSSIBILITY OF SUCH DAMAGE.
30 1.1 hannken */
31 1.1 hannken
32 1.1 hannken #include <sys/cdefs.h>
33 1.37 hannken __KERNEL_RCSID(0, "$NetBSD: vfs_trans.c,v 1.37 2017/02/23 11:23:22 hannken Exp $");
34 1.1 hannken
35 1.1 hannken /*
36 1.1 hannken * File system transaction operations.
37 1.1 hannken */
38 1.1 hannken
39 1.34 pooka #ifdef _KERNEL_OPT
40 1.1 hannken #include "opt_ddb.h"
41 1.34 pooka #endif
42 1.1 hannken
43 1.1 hannken #include <sys/param.h>
44 1.1 hannken #include <sys/systm.h>
45 1.26 hannken #include <sys/atomic.h>
46 1.24 pooka #include <sys/buf.h>
47 1.12 hannken #include <sys/kmem.h>
48 1.1 hannken #include <sys/mount.h>
49 1.26 hannken #include <sys/pserialize.h>
50 1.1 hannken #include <sys/vnode.h>
51 1.1 hannken #define _FSTRANS_API_PRIVATE
52 1.1 hannken #include <sys/fstrans.h>
53 1.10 ad #include <sys/proc.h>
54 1.1 hannken
55 1.12 hannken #include <miscfs/specfs/specdev.h>
56 1.1 hannken
57 1.16 ad struct fscow_handler {
58 1.26 hannken LIST_ENTRY(fscow_handler) ch_list;
59 1.16 ad int (*ch_func)(void *, struct buf *, bool);
60 1.16 ad void *ch_arg;
61 1.16 ad };
62 1.1 hannken struct fstrans_lwp_info {
63 1.1 hannken struct fstrans_lwp_info *fli_succ;
64 1.26 hannken struct lwp *fli_self;
65 1.1 hannken struct mount *fli_mount;
66 1.20 hannken int fli_trans_cnt;
67 1.20 hannken int fli_cow_cnt;
68 1.1 hannken enum fstrans_lock_type fli_lock_type;
69 1.26 hannken LIST_ENTRY(fstrans_lwp_info) fli_list;
70 1.1 hannken };
71 1.1 hannken struct fstrans_mount_info {
72 1.1 hannken enum fstrans_state fmi_state;
73 1.26 hannken unsigned int fmi_ref_cnt;
74 1.26 hannken bool fmi_cow_change;
75 1.26 hannken LIST_HEAD(, fscow_handler) fmi_cow_handler;
76 1.1 hannken };
77 1.1 hannken
78 1.26 hannken static specificdata_key_t lwp_data_key; /* Our specific data key. */
79 1.4 ad static kmutex_t vfs_suspend_lock; /* Serialize suspensions. */
80 1.26 hannken static kmutex_t fstrans_lock; /* Fstrans big lock. */
81 1.35 hannken static kmutex_t fstrans_mount_lock; /* Fstrans mount big lock. */
82 1.26 hannken static kcondvar_t fstrans_state_cv; /* Fstrans or cow state changed. */
83 1.26 hannken static kcondvar_t fstrans_count_cv; /* Fstrans or cow count changed. */
84 1.26 hannken static pserialize_t fstrans_psz; /* Pserialize state. */
85 1.26 hannken static LIST_HEAD(fstrans_lwp_head, fstrans_lwp_info) fstrans_fli_head;
86 1.26 hannken /* List of all fstrans_lwp_info. */
87 1.1 hannken
88 1.1 hannken static void fstrans_lwp_dtor(void *);
89 1.26 hannken static void fstrans_mount_dtor(struct mount *);
90 1.26 hannken static struct fstrans_lwp_info *fstrans_get_lwp_info(struct mount *, bool);
91 1.26 hannken static bool grant_lock(const enum fstrans_state, const enum fstrans_lock_type);
92 1.26 hannken static bool state_change_done(const struct mount *);
93 1.26 hannken static bool cow_state_change_done(const struct mount *);
94 1.26 hannken static void cow_change_enter(const struct mount *);
95 1.26 hannken static void cow_change_done(const struct mount *);
96 1.1 hannken
97 1.1 hannken /*
98 1.26 hannken * Initialize.
99 1.1 hannken */
100 1.1 hannken void
101 1.1 hannken fstrans_init(void)
102 1.1 hannken {
103 1.28 martin int error __diagused;
104 1.1 hannken
105 1.1 hannken error = lwp_specific_key_create(&lwp_data_key, fstrans_lwp_dtor);
106 1.1 hannken KASSERT(error == 0);
107 1.7 ad
108 1.4 ad mutex_init(&vfs_suspend_lock, MUTEX_DEFAULT, IPL_NONE);
109 1.26 hannken mutex_init(&fstrans_lock, MUTEX_DEFAULT, IPL_NONE);
110 1.35 hannken mutex_init(&fstrans_mount_lock, MUTEX_DEFAULT, IPL_NONE);
111 1.26 hannken cv_init(&fstrans_state_cv, "fstchg");
112 1.26 hannken cv_init(&fstrans_count_cv, "fstcnt");
113 1.26 hannken fstrans_psz = pserialize_create();
114 1.26 hannken LIST_INIT(&fstrans_fli_head);
115 1.1 hannken }
116 1.1 hannken
117 1.1 hannken /*
118 1.26 hannken * Deallocate lwp state.
119 1.1 hannken */
120 1.1 hannken static void
121 1.1 hannken fstrans_lwp_dtor(void *arg)
122 1.1 hannken {
123 1.1 hannken struct fstrans_lwp_info *fli, *fli_next;
124 1.1 hannken
125 1.1 hannken for (fli = arg; fli; fli = fli_next) {
126 1.20 hannken KASSERT(fli->fli_trans_cnt == 0);
127 1.20 hannken KASSERT(fli->fli_cow_cnt == 0);
128 1.26 hannken if (fli->fli_mount != NULL)
129 1.26 hannken fstrans_mount_dtor(fli->fli_mount);
130 1.1 hannken fli_next = fli->fli_succ;
131 1.30 hannken fli->fli_mount = NULL;
132 1.30 hannken membar_sync();
133 1.30 hannken fli->fli_self = NULL;
134 1.1 hannken }
135 1.26 hannken }
136 1.26 hannken
137 1.26 hannken /*
138 1.26 hannken * Dereference mount state.
139 1.26 hannken */
140 1.26 hannken static void
141 1.26 hannken fstrans_mount_dtor(struct mount *mp)
142 1.26 hannken {
143 1.26 hannken struct fstrans_mount_info *fmi;
144 1.26 hannken
145 1.35 hannken mutex_enter(&fstrans_mount_lock);
146 1.35 hannken
147 1.26 hannken fmi = mp->mnt_transinfo;
148 1.35 hannken KASSERT(fmi != NULL);
149 1.35 hannken fmi->fmi_ref_cnt -= 1;
150 1.35 hannken if (fmi->fmi_ref_cnt > 0) {
151 1.35 hannken mutex_exit(&fstrans_mount_lock);
152 1.26 hannken return;
153 1.35 hannken }
154 1.26 hannken
155 1.26 hannken KASSERT(fmi->fmi_state == FSTRANS_NORMAL);
156 1.26 hannken KASSERT(LIST_FIRST(&fmi->fmi_cow_handler) == NULL);
157 1.26 hannken
158 1.26 hannken mp->mnt_iflag &= ~IMNT_HAS_TRANS;
159 1.26 hannken mp->mnt_transinfo = NULL;
160 1.26 hannken
161 1.35 hannken mutex_exit(&fstrans_mount_lock);
162 1.35 hannken
163 1.35 hannken kmem_free(fmi, sizeof(*fmi));
164 1.26 hannken vfs_destroy(mp);
165 1.1 hannken }
166 1.1 hannken
167 1.1 hannken /*
168 1.26 hannken * Allocate mount state.
169 1.1 hannken */
170 1.16 ad int
171 1.16 ad fstrans_mount(struct mount *mp)
172 1.1 hannken {
173 1.26 hannken int error;
174 1.31 matt struct fstrans_mount_info *newfmi;
175 1.16 ad
176 1.26 hannken error = vfs_busy(mp, NULL);
177 1.26 hannken if (error)
178 1.26 hannken return error;
179 1.32 pooka newfmi = kmem_alloc(sizeof(*newfmi), KM_SLEEP);
180 1.31 matt newfmi->fmi_state = FSTRANS_NORMAL;
181 1.31 matt newfmi->fmi_ref_cnt = 1;
182 1.31 matt LIST_INIT(&newfmi->fmi_cow_handler);
183 1.31 matt newfmi->fmi_cow_change = false;
184 1.16 ad
185 1.35 hannken mutex_enter(&fstrans_mount_lock);
186 1.31 matt mp->mnt_transinfo = newfmi;
187 1.16 ad mp->mnt_iflag |= IMNT_HAS_TRANS;
188 1.35 hannken mutex_exit(&fstrans_mount_lock);
189 1.1 hannken
190 1.26 hannken vfs_unbusy(mp, true, NULL);
191 1.26 hannken
192 1.16 ad return 0;
193 1.1 hannken }
194 1.1 hannken
195 1.1 hannken /*
196 1.26 hannken * Deallocate mount state.
197 1.1 hannken */
198 1.16 ad void
199 1.16 ad fstrans_unmount(struct mount *mp)
200 1.1 hannken {
201 1.1 hannken
202 1.26 hannken KASSERT(mp->mnt_transinfo != NULL);
203 1.1 hannken
204 1.26 hannken fstrans_mount_dtor(mp);
205 1.1 hannken }
206 1.1 hannken
207 1.1 hannken /*
208 1.26 hannken * Retrieve the per lwp info for this mount allocating if necessary.
209 1.20 hannken */
210 1.20 hannken static struct fstrans_lwp_info *
211 1.26 hannken fstrans_get_lwp_info(struct mount *mp, bool do_alloc)
212 1.20 hannken {
213 1.26 hannken struct fstrans_lwp_info *fli, *res;
214 1.26 hannken struct fstrans_mount_info *fmi;
215 1.20 hannken
216 1.26 hannken /*
217 1.26 hannken * Scan our list for a match clearing entries whose mount is gone.
218 1.26 hannken */
219 1.26 hannken res = NULL;
220 1.20 hannken for (fli = lwp_getspecific(lwp_data_key); fli; fli = fli->fli_succ) {
221 1.26 hannken if (fli->fli_mount == mp) {
222 1.26 hannken KASSERT(res == NULL);
223 1.26 hannken res = fli;
224 1.26 hannken } else if (fli->fli_mount != NULL &&
225 1.26 hannken (fli->fli_mount->mnt_iflag & IMNT_GONE) != 0 &&
226 1.26 hannken fli->fli_trans_cnt == 0 && fli->fli_cow_cnt == 0) {
227 1.26 hannken fstrans_mount_dtor(fli->fli_mount);
228 1.26 hannken fli->fli_mount = NULL;
229 1.26 hannken }
230 1.20 hannken }
231 1.26 hannken if (__predict_true(res != NULL))
232 1.26 hannken return res;
233 1.20 hannken
234 1.26 hannken if (! do_alloc)
235 1.26 hannken return NULL;
236 1.26 hannken
237 1.26 hannken /*
238 1.37 hannken * Does this file system support fstrans?
239 1.37 hannken */
240 1.37 hannken mutex_enter(&fstrans_mount_lock);
241 1.37 hannken if ((mp->mnt_iflag & IMNT_HAS_TRANS) == 0) {
242 1.37 hannken mutex_exit(&fstrans_mount_lock);
243 1.37 hannken return NULL;
244 1.37 hannken }
245 1.37 hannken mutex_exit(&fstrans_mount_lock);
246 1.37 hannken
247 1.37 hannken /*
248 1.26 hannken * Try to reuse a cleared entry or allocate a new one.
249 1.26 hannken */
250 1.26 hannken for (fli = lwp_getspecific(lwp_data_key); fli; fli = fli->fli_succ) {
251 1.26 hannken if (fli->fli_mount == NULL) {
252 1.26 hannken KASSERT(fli->fli_trans_cnt == 0);
253 1.26 hannken KASSERT(fli->fli_cow_cnt == 0);
254 1.26 hannken break;
255 1.26 hannken }
256 1.26 hannken }
257 1.26 hannken if (fli == NULL) {
258 1.30 hannken mutex_enter(&fstrans_lock);
259 1.30 hannken LIST_FOREACH(fli, &fstrans_fli_head, fli_list) {
260 1.30 hannken if (fli->fli_self == NULL) {
261 1.35 hannken KASSERT(fli->fli_mount == NULL);
262 1.30 hannken KASSERT(fli->fli_trans_cnt == 0);
263 1.30 hannken KASSERT(fli->fli_cow_cnt == 0);
264 1.30 hannken fli->fli_self = curlwp;
265 1.30 hannken fli->fli_succ = lwp_getspecific(lwp_data_key);
266 1.30 hannken lwp_setspecific(lwp_data_key, fli);
267 1.30 hannken break;
268 1.30 hannken }
269 1.30 hannken }
270 1.30 hannken mutex_exit(&fstrans_lock);
271 1.30 hannken }
272 1.30 hannken if (fli == NULL) {
273 1.30 hannken fli = kmem_alloc(sizeof(*fli), KM_SLEEP);
274 1.26 hannken mutex_enter(&fstrans_lock);
275 1.26 hannken memset(fli, 0, sizeof(*fli));
276 1.26 hannken fli->fli_self = curlwp;
277 1.26 hannken LIST_INSERT_HEAD(&fstrans_fli_head, fli, fli_list);
278 1.26 hannken mutex_exit(&fstrans_lock);
279 1.26 hannken fli->fli_succ = lwp_getspecific(lwp_data_key);
280 1.26 hannken lwp_setspecific(lwp_data_key, fli);
281 1.20 hannken }
282 1.20 hannken
283 1.26 hannken /*
284 1.26 hannken * Attach the entry to the mount.
285 1.26 hannken */
286 1.35 hannken mutex_enter(&fstrans_mount_lock);
287 1.37 hannken fmi = mp->mnt_transinfo;
288 1.37 hannken KASSERT(fmi != NULL);
289 1.37 hannken fli->fli_mount = mp;
290 1.37 hannken fmi->fmi_ref_cnt += 1;
291 1.35 hannken mutex_exit(&fstrans_mount_lock);
292 1.26 hannken
293 1.26 hannken return fli;
294 1.26 hannken }
295 1.26 hannken
296 1.26 hannken /*
297 1.26 hannken * Check if this lock type is granted at this state.
298 1.26 hannken */
299 1.26 hannken static bool
300 1.26 hannken grant_lock(const enum fstrans_state state, const enum fstrans_lock_type type)
301 1.26 hannken {
302 1.20 hannken
303 1.26 hannken if (__predict_true(state == FSTRANS_NORMAL))
304 1.26 hannken return true;
305 1.26 hannken if (type == FSTRANS_EXCL)
306 1.26 hannken return true;
307 1.26 hannken if (state == FSTRANS_SUSPENDING && type == FSTRANS_LAZY)
308 1.26 hannken return true;
309 1.20 hannken
310 1.26 hannken return false;
311 1.20 hannken }
312 1.20 hannken
313 1.20 hannken /*
314 1.1 hannken * Start a transaction. If this thread already has a transaction on this
315 1.1 hannken * file system increment the reference counter.
316 1.1 hannken */
317 1.1 hannken int
318 1.1 hannken _fstrans_start(struct mount *mp, enum fstrans_lock_type lock_type, int wait)
319 1.1 hannken {
320 1.26 hannken int s;
321 1.20 hannken struct fstrans_lwp_info *fli;
322 1.1 hannken struct fstrans_mount_info *fmi;
323 1.1 hannken
324 1.18 yamt ASSERT_SLEEPABLE();
325 1.1 hannken
326 1.35 hannken if (mp == NULL || (fli = fstrans_get_lwp_info(mp, true)) == NULL)
327 1.1 hannken return 0;
328 1.1 hannken
329 1.20 hannken if (fli->fli_trans_cnt > 0) {
330 1.26 hannken KASSERT(lock_type != FSTRANS_EXCL);
331 1.20 hannken fli->fli_trans_cnt += 1;
332 1.26 hannken
333 1.20 hannken return 0;
334 1.1 hannken }
335 1.1 hannken
336 1.26 hannken s = pserialize_read_enter();
337 1.16 ad fmi = mp->mnt_transinfo;
338 1.26 hannken if (__predict_true(grant_lock(fmi->fmi_state, lock_type))) {
339 1.26 hannken fli->fli_trans_cnt = 1;
340 1.26 hannken fli->fli_lock_type = lock_type;
341 1.26 hannken pserialize_read_exit(s);
342 1.1 hannken
343 1.26 hannken return 0;
344 1.26 hannken }
345 1.26 hannken pserialize_read_exit(s);
346 1.8 hannken
347 1.26 hannken if (! wait)
348 1.8 hannken return EBUSY;
349 1.1 hannken
350 1.26 hannken mutex_enter(&fstrans_lock);
351 1.26 hannken while (! grant_lock(fmi->fmi_state, lock_type))
352 1.26 hannken cv_wait(&fstrans_state_cv, &fstrans_lock);
353 1.20 hannken fli->fli_trans_cnt = 1;
354 1.20 hannken fli->fli_lock_type = lock_type;
355 1.26 hannken mutex_exit(&fstrans_lock);
356 1.1 hannken
357 1.1 hannken return 0;
358 1.1 hannken }
359 1.1 hannken
360 1.1 hannken /*
361 1.1 hannken * Finish a transaction.
362 1.1 hannken */
363 1.1 hannken void
364 1.1 hannken fstrans_done(struct mount *mp)
365 1.1 hannken {
366 1.26 hannken int s;
367 1.1 hannken struct fstrans_lwp_info *fli;
368 1.1 hannken struct fstrans_mount_info *fmi;
369 1.1 hannken
370 1.35 hannken if (mp == NULL || (fli = fstrans_get_lwp_info(mp, true)) == NULL)
371 1.1 hannken return;
372 1.1 hannken
373 1.26 hannken KASSERT(fli->fli_trans_cnt > 0);
374 1.26 hannken
375 1.26 hannken if (fli->fli_trans_cnt > 1) {
376 1.26 hannken fli->fli_trans_cnt -= 1;
377 1.26 hannken
378 1.26 hannken return;
379 1.1 hannken }
380 1.1 hannken
381 1.26 hannken s = pserialize_read_enter();
382 1.26 hannken fmi = mp->mnt_transinfo;
383 1.26 hannken if (__predict_true(fmi->fmi_state == FSTRANS_NORMAL)) {
384 1.26 hannken fli->fli_trans_cnt = 0;
385 1.26 hannken pserialize_read_exit(s);
386 1.26 hannken
387 1.26 hannken return;
388 1.26 hannken }
389 1.26 hannken pserialize_read_exit(s);
390 1.20 hannken
391 1.26 hannken mutex_enter(&fstrans_lock);
392 1.26 hannken fli->fli_trans_cnt = 0;
393 1.26 hannken cv_signal(&fstrans_count_cv);
394 1.26 hannken mutex_exit(&fstrans_lock);
395 1.1 hannken }
396 1.1 hannken
397 1.1 hannken /*
398 1.1 hannken * Check if this thread has an exclusive lock.
399 1.1 hannken */
400 1.1 hannken int
401 1.1 hannken fstrans_is_owner(struct mount *mp)
402 1.1 hannken {
403 1.1 hannken struct fstrans_lwp_info *fli;
404 1.1 hannken
405 1.35 hannken if (mp == NULL || (fli = fstrans_get_lwp_info(mp, false)) == NULL)
406 1.1 hannken return 0;
407 1.1 hannken
408 1.35 hannken if (fli->fli_trans_cnt == 0)
409 1.1 hannken return 0;
410 1.1 hannken
411 1.1 hannken KASSERT(fli->fli_mount == mp);
412 1.20 hannken KASSERT(fli->fli_trans_cnt > 0);
413 1.26 hannken
414 1.2 hannken return (fli->fli_lock_type == FSTRANS_EXCL);
415 1.1 hannken }
416 1.1 hannken
417 1.1 hannken /*
418 1.26 hannken * True, if no thread is in a transaction not granted at the current state.
419 1.26 hannken */
420 1.26 hannken static bool
421 1.26 hannken state_change_done(const struct mount *mp)
422 1.26 hannken {
423 1.26 hannken struct fstrans_lwp_info *fli;
424 1.26 hannken struct fstrans_mount_info *fmi;
425 1.26 hannken
426 1.26 hannken KASSERT(mutex_owned(&fstrans_lock));
427 1.26 hannken
428 1.26 hannken fmi = mp->mnt_transinfo;
429 1.26 hannken LIST_FOREACH(fli, &fstrans_fli_head, fli_list) {
430 1.26 hannken if (fli->fli_mount != mp)
431 1.26 hannken continue;
432 1.26 hannken if (fli->fli_trans_cnt == 0)
433 1.26 hannken continue;
434 1.26 hannken if (grant_lock(fmi->fmi_state, fli->fli_lock_type))
435 1.26 hannken continue;
436 1.26 hannken
437 1.26 hannken return false;
438 1.26 hannken }
439 1.26 hannken
440 1.26 hannken return true;
441 1.26 hannken }
442 1.26 hannken
443 1.26 hannken /*
444 1.1 hannken * Set new file system state.
445 1.1 hannken */
446 1.1 hannken int
447 1.1 hannken fstrans_setstate(struct mount *mp, enum fstrans_state new_state)
448 1.1 hannken {
449 1.26 hannken int error;
450 1.26 hannken enum fstrans_state old_state;
451 1.1 hannken struct fstrans_mount_info *fmi;
452 1.1 hannken
453 1.16 ad fmi = mp->mnt_transinfo;
454 1.26 hannken old_state = fmi->fmi_state;
455 1.26 hannken if (old_state == new_state)
456 1.26 hannken return 0;
457 1.1 hannken
458 1.26 hannken mutex_enter(&fstrans_lock);
459 1.26 hannken fmi->fmi_state = new_state;
460 1.26 hannken pserialize_perform(fstrans_psz);
461 1.26 hannken
462 1.26 hannken /*
463 1.26 hannken * All threads see the new state now.
464 1.26 hannken * Wait for transactions invalid at this state to leave.
465 1.26 hannken */
466 1.26 hannken error = 0;
467 1.26 hannken while (! state_change_done(mp)) {
468 1.26 hannken error = cv_wait_sig(&fstrans_count_cv, &fstrans_lock);
469 1.26 hannken if (error) {
470 1.26 hannken new_state = fmi->fmi_state = FSTRANS_NORMAL;
471 1.26 hannken break;
472 1.26 hannken }
473 1.26 hannken }
474 1.26 hannken cv_broadcast(&fstrans_state_cv);
475 1.26 hannken mutex_exit(&fstrans_lock);
476 1.1 hannken
477 1.26 hannken if (old_state != new_state) {
478 1.26 hannken if (old_state == FSTRANS_NORMAL)
479 1.9 hannken fstrans_start(mp, FSTRANS_EXCL);
480 1.26 hannken if (new_state == FSTRANS_NORMAL)
481 1.1 hannken fstrans_done(mp);
482 1.1 hannken }
483 1.1 hannken
484 1.26 hannken return error;
485 1.1 hannken }
486 1.1 hannken
487 1.1 hannken /*
488 1.26 hannken * Get current file system state.
489 1.1 hannken */
490 1.1 hannken enum fstrans_state
491 1.1 hannken fstrans_getstate(struct mount *mp)
492 1.1 hannken {
493 1.1 hannken struct fstrans_mount_info *fmi;
494 1.1 hannken
495 1.16 ad fmi = mp->mnt_transinfo;
496 1.26 hannken KASSERT(fmi != NULL);
497 1.1 hannken
498 1.1 hannken return fmi->fmi_state;
499 1.1 hannken }
500 1.1 hannken
501 1.1 hannken /*
502 1.1 hannken * Request a filesystem to suspend all operations.
503 1.1 hannken */
504 1.1 hannken int
505 1.1 hannken vfs_suspend(struct mount *mp, int nowait)
506 1.1 hannken {
507 1.4 ad int error;
508 1.1 hannken
509 1.4 ad if (nowait) {
510 1.4 ad if (!mutex_tryenter(&vfs_suspend_lock))
511 1.4 ad return EWOULDBLOCK;
512 1.4 ad } else
513 1.4 ad mutex_enter(&vfs_suspend_lock);
514 1.1 hannken
515 1.36 hannken if ((error = VFS_SUSPENDCTL(mp, SUSPEND_SUSPEND)) != 0)
516 1.4 ad mutex_exit(&vfs_suspend_lock);
517 1.1 hannken
518 1.1 hannken return error;
519 1.1 hannken }
520 1.1 hannken
521 1.1 hannken /*
522 1.1 hannken * Request a filesystem to resume all operations.
523 1.1 hannken */
524 1.1 hannken void
525 1.1 hannken vfs_resume(struct mount *mp)
526 1.1 hannken {
527 1.1 hannken
528 1.1 hannken VFS_SUSPENDCTL(mp, SUSPEND_RESUME);
529 1.4 ad mutex_exit(&vfs_suspend_lock);
530 1.1 hannken }
531 1.1 hannken
532 1.1 hannken
533 1.26 hannken /*
534 1.26 hannken * True, if no thread is running a cow handler.
535 1.26 hannken */
536 1.26 hannken static bool
537 1.26 hannken cow_state_change_done(const struct mount *mp)
538 1.1 hannken {
539 1.1 hannken struct fstrans_lwp_info *fli;
540 1.28 martin struct fstrans_mount_info *fmi __diagused;
541 1.26 hannken
542 1.26 hannken fmi = mp->mnt_transinfo;
543 1.1 hannken
544 1.26 hannken KASSERT(mutex_owned(&fstrans_lock));
545 1.26 hannken KASSERT(fmi->fmi_cow_change);
546 1.26 hannken
547 1.26 hannken LIST_FOREACH(fli, &fstrans_fli_head, fli_list) {
548 1.26 hannken if (fli->fli_mount != mp)
549 1.26 hannken continue;
550 1.26 hannken if (fli->fli_cow_cnt == 0)
551 1.1 hannken continue;
552 1.26 hannken
553 1.26 hannken return false;
554 1.1 hannken }
555 1.26 hannken
556 1.26 hannken return true;
557 1.1 hannken }
558 1.1 hannken
559 1.26 hannken /*
560 1.26 hannken * Prepare for changing this mounts cow list.
561 1.26 hannken * Returns with fstrans_lock locked.
562 1.26 hannken */
563 1.1 hannken static void
564 1.26 hannken cow_change_enter(const struct mount *mp)
565 1.1 hannken {
566 1.1 hannken struct fstrans_mount_info *fmi;
567 1.1 hannken
568 1.16 ad fmi = mp->mnt_transinfo;
569 1.1 hannken
570 1.26 hannken mutex_enter(&fstrans_lock);
571 1.26 hannken
572 1.26 hannken /*
573 1.26 hannken * Wait for other threads changing the list.
574 1.26 hannken */
575 1.26 hannken while (fmi->fmi_cow_change)
576 1.26 hannken cv_wait(&fstrans_state_cv, &fstrans_lock);
577 1.26 hannken
578 1.26 hannken /*
579 1.26 hannken * Wait until all threads are aware of a state change.
580 1.26 hannken */
581 1.26 hannken fmi->fmi_cow_change = true;
582 1.26 hannken pserialize_perform(fstrans_psz);
583 1.26 hannken
584 1.26 hannken while (! cow_state_change_done(mp))
585 1.26 hannken cv_wait(&fstrans_count_cv, &fstrans_lock);
586 1.1 hannken }
587 1.1 hannken
588 1.26 hannken /*
589 1.26 hannken * Done changing this mounts cow list.
590 1.26 hannken */
591 1.26 hannken static void
592 1.26 hannken cow_change_done(const struct mount *mp)
593 1.1 hannken {
594 1.26 hannken struct fstrans_mount_info *fmi;
595 1.26 hannken
596 1.26 hannken KASSERT(mutex_owned(&fstrans_lock));
597 1.26 hannken
598 1.26 hannken fmi = mp->mnt_transinfo;
599 1.26 hannken
600 1.26 hannken fmi->fmi_cow_change = false;
601 1.26 hannken pserialize_perform(fstrans_psz);
602 1.1 hannken
603 1.26 hannken cv_broadcast(&fstrans_state_cv);
604 1.1 hannken
605 1.26 hannken mutex_exit(&fstrans_lock);
606 1.1 hannken }
607 1.12 hannken
608 1.26 hannken /*
609 1.26 hannken * Add a handler to this mount.
610 1.26 hannken */
611 1.12 hannken int
612 1.15 hannken fscow_establish(struct mount *mp, int (*func)(void *, struct buf *, bool),
613 1.15 hannken void *arg)
614 1.12 hannken {
615 1.16 ad struct fstrans_mount_info *fmi;
616 1.31 matt struct fscow_handler *newch;
617 1.12 hannken
618 1.16 ad if ((mp->mnt_iflag & IMNT_HAS_TRANS) == 0)
619 1.16 ad return EINVAL;
620 1.16 ad
621 1.16 ad fmi = mp->mnt_transinfo;
622 1.26 hannken KASSERT(fmi != NULL);
623 1.12 hannken
624 1.32 pooka newch = kmem_alloc(sizeof(*newch), KM_SLEEP);
625 1.31 matt newch->ch_func = func;
626 1.31 matt newch->ch_arg = arg;
627 1.26 hannken
628 1.26 hannken cow_change_enter(mp);
629 1.31 matt LIST_INSERT_HEAD(&fmi->fmi_cow_handler, newch, ch_list);
630 1.26 hannken cow_change_done(mp);
631 1.12 hannken
632 1.12 hannken return 0;
633 1.12 hannken }
634 1.12 hannken
635 1.26 hannken /*
636 1.26 hannken * Remove a handler from this mount.
637 1.26 hannken */
638 1.12 hannken int
639 1.15 hannken fscow_disestablish(struct mount *mp, int (*func)(void *, struct buf *, bool),
640 1.12 hannken void *arg)
641 1.12 hannken {
642 1.16 ad struct fstrans_mount_info *fmi;
643 1.12 hannken struct fscow_handler *hp = NULL;
644 1.12 hannken
645 1.16 ad if ((mp->mnt_iflag & IMNT_HAS_TRANS) == 0)
646 1.12 hannken return EINVAL;
647 1.12 hannken
648 1.16 ad fmi = mp->mnt_transinfo;
649 1.26 hannken KASSERT(fmi != NULL);
650 1.16 ad
651 1.26 hannken cow_change_enter(mp);
652 1.26 hannken LIST_FOREACH(hp, &fmi->fmi_cow_handler, ch_list)
653 1.12 hannken if (hp->ch_func == func && hp->ch_arg == arg)
654 1.12 hannken break;
655 1.12 hannken if (hp != NULL) {
656 1.26 hannken LIST_REMOVE(hp, ch_list);
657 1.12 hannken kmem_free(hp, sizeof(*hp));
658 1.12 hannken }
659 1.26 hannken cow_change_done(mp);
660 1.12 hannken
661 1.12 hannken return hp ? 0 : EINVAL;
662 1.12 hannken }
663 1.12 hannken
664 1.26 hannken /*
665 1.26 hannken * Check for need to copy block that is about to be written.
666 1.26 hannken */
667 1.12 hannken int
668 1.15 hannken fscow_run(struct buf *bp, bool data_valid)
669 1.12 hannken {
670 1.26 hannken int error, s;
671 1.12 hannken struct mount *mp;
672 1.20 hannken struct fstrans_lwp_info *fli;
673 1.16 ad struct fstrans_mount_info *fmi;
674 1.12 hannken struct fscow_handler *hp;
675 1.12 hannken
676 1.26 hannken /*
677 1.26 hannken * First check if we need run the copy-on-write handler.
678 1.26 hannken */
679 1.17 hannken if ((bp->b_flags & B_COWDONE))
680 1.26 hannken return 0;
681 1.26 hannken if (bp->b_vp == NULL) {
682 1.26 hannken bp->b_flags |= B_COWDONE;
683 1.26 hannken return 0;
684 1.26 hannken }
685 1.12 hannken if (bp->b_vp->v_type == VBLK)
686 1.27 hannken mp = spec_node_getmountedfs(bp->b_vp);
687 1.12 hannken else
688 1.12 hannken mp = bp->b_vp->v_mount;
689 1.26 hannken if (mp == NULL || (mp->mnt_iflag & IMNT_HAS_TRANS) == 0) {
690 1.26 hannken bp->b_flags |= B_COWDONE;
691 1.26 hannken return 0;
692 1.26 hannken }
693 1.12 hannken
694 1.26 hannken fli = fstrans_get_lwp_info(mp, true);
695 1.16 ad fmi = mp->mnt_transinfo;
696 1.12 hannken
697 1.26 hannken /*
698 1.26 hannken * On non-recursed run check if other threads
699 1.26 hannken * want to change the list.
700 1.26 hannken */
701 1.26 hannken if (fli->fli_cow_cnt == 0) {
702 1.26 hannken s = pserialize_read_enter();
703 1.26 hannken if (__predict_false(fmi->fmi_cow_change)) {
704 1.26 hannken pserialize_read_exit(s);
705 1.26 hannken mutex_enter(&fstrans_lock);
706 1.26 hannken while (fmi->fmi_cow_change)
707 1.26 hannken cv_wait(&fstrans_state_cv, &fstrans_lock);
708 1.26 hannken fli->fli_cow_cnt = 1;
709 1.26 hannken mutex_exit(&fstrans_lock);
710 1.26 hannken } else {
711 1.26 hannken fli->fli_cow_cnt = 1;
712 1.26 hannken pserialize_read_exit(s);
713 1.26 hannken }
714 1.26 hannken } else
715 1.26 hannken fli->fli_cow_cnt += 1;
716 1.20 hannken
717 1.26 hannken /*
718 1.26 hannken * Run all copy-on-write handlers, stop on error.
719 1.26 hannken */
720 1.26 hannken error = 0;
721 1.26 hannken LIST_FOREACH(hp, &fmi->fmi_cow_handler, ch_list)
722 1.15 hannken if ((error = (*hp->ch_func)(hp->ch_arg, bp, data_valid)) != 0)
723 1.12 hannken break;
724 1.17 hannken if (error == 0)
725 1.17 hannken bp->b_flags |= B_COWDONE;
726 1.15 hannken
727 1.26 hannken /*
728 1.26 hannken * Check if other threads want to change the list.
729 1.26 hannken */
730 1.26 hannken if (fli->fli_cow_cnt > 1) {
731 1.26 hannken fli->fli_cow_cnt -= 1;
732 1.26 hannken } else {
733 1.26 hannken s = pserialize_read_enter();
734 1.26 hannken if (__predict_false(fmi->fmi_cow_change)) {
735 1.26 hannken pserialize_read_exit(s);
736 1.26 hannken mutex_enter(&fstrans_lock);
737 1.26 hannken fli->fli_cow_cnt = 0;
738 1.26 hannken cv_signal(&fstrans_count_cv);
739 1.26 hannken mutex_exit(&fstrans_lock);
740 1.26 hannken } else {
741 1.26 hannken fli->fli_cow_cnt = 0;
742 1.26 hannken pserialize_read_exit(s);
743 1.26 hannken }
744 1.26 hannken }
745 1.26 hannken
746 1.12 hannken return error;
747 1.12 hannken }
748 1.26 hannken
749 1.26 hannken #if defined(DDB)
750 1.26 hannken void fstrans_dump(int);
751 1.26 hannken
752 1.26 hannken static void
753 1.26 hannken fstrans_print_lwp(struct proc *p, struct lwp *l, int verbose)
754 1.26 hannken {
755 1.26 hannken char prefix[9];
756 1.26 hannken struct fstrans_lwp_info *fli;
757 1.26 hannken
758 1.26 hannken snprintf(prefix, sizeof(prefix), "%d.%d", p->p_pid, l->l_lid);
759 1.26 hannken LIST_FOREACH(fli, &fstrans_fli_head, fli_list) {
760 1.26 hannken if (fli->fli_self != l)
761 1.26 hannken continue;
762 1.26 hannken if (fli->fli_trans_cnt == 0 && fli->fli_cow_cnt == 0) {
763 1.26 hannken if (! verbose)
764 1.26 hannken continue;
765 1.26 hannken }
766 1.26 hannken printf("%-8s", prefix);
767 1.26 hannken if (verbose)
768 1.26 hannken printf(" @%p", fli);
769 1.26 hannken if (fli->fli_mount != NULL)
770 1.26 hannken printf(" (%s)", fli->fli_mount->mnt_stat.f_mntonname);
771 1.26 hannken else
772 1.26 hannken printf(" NULL");
773 1.26 hannken if (fli->fli_trans_cnt == 0) {
774 1.26 hannken printf(" -");
775 1.26 hannken } else {
776 1.26 hannken switch (fli->fli_lock_type) {
777 1.26 hannken case FSTRANS_LAZY:
778 1.26 hannken printf(" lazy");
779 1.26 hannken break;
780 1.26 hannken case FSTRANS_SHARED:
781 1.26 hannken printf(" shared");
782 1.26 hannken break;
783 1.26 hannken case FSTRANS_EXCL:
784 1.26 hannken printf(" excl");
785 1.26 hannken break;
786 1.26 hannken default:
787 1.26 hannken printf(" %#x", fli->fli_lock_type);
788 1.26 hannken break;
789 1.26 hannken }
790 1.26 hannken }
791 1.26 hannken printf(" %d cow %d\n", fli->fli_trans_cnt, fli->fli_cow_cnt);
792 1.26 hannken prefix[0] = '\0';
793 1.26 hannken }
794 1.26 hannken }
795 1.26 hannken
796 1.26 hannken static void
797 1.26 hannken fstrans_print_mount(struct mount *mp, int verbose)
798 1.26 hannken {
799 1.26 hannken struct fstrans_mount_info *fmi;
800 1.26 hannken
801 1.26 hannken fmi = mp->mnt_transinfo;
802 1.26 hannken if (!verbose && (fmi == NULL || fmi->fmi_state == FSTRANS_NORMAL))
803 1.26 hannken return;
804 1.26 hannken
805 1.26 hannken printf("%-16s ", mp->mnt_stat.f_mntonname);
806 1.26 hannken if (fmi == NULL) {
807 1.26 hannken printf("(null)\n");
808 1.26 hannken return;
809 1.26 hannken }
810 1.26 hannken switch (fmi->fmi_state) {
811 1.26 hannken case FSTRANS_NORMAL:
812 1.26 hannken printf("state normal\n");
813 1.26 hannken break;
814 1.26 hannken case FSTRANS_SUSPENDING:
815 1.26 hannken printf("state suspending\n");
816 1.26 hannken break;
817 1.26 hannken case FSTRANS_SUSPENDED:
818 1.26 hannken printf("state suspended\n");
819 1.26 hannken break;
820 1.26 hannken default:
821 1.26 hannken printf("state %#x\n", fmi->fmi_state);
822 1.26 hannken break;
823 1.26 hannken }
824 1.26 hannken }
825 1.26 hannken
826 1.26 hannken void
827 1.26 hannken fstrans_dump(int full)
828 1.26 hannken {
829 1.26 hannken const struct proclist_desc *pd;
830 1.26 hannken struct proc *p;
831 1.26 hannken struct lwp *l;
832 1.26 hannken struct mount *mp;
833 1.26 hannken
834 1.26 hannken printf("Fstrans locks by lwp:\n");
835 1.26 hannken for (pd = proclists; pd->pd_list != NULL; pd++)
836 1.26 hannken PROCLIST_FOREACH(p, pd->pd_list)
837 1.26 hannken LIST_FOREACH(l, &p->p_lwps, l_sibling)
838 1.26 hannken fstrans_print_lwp(p, l, full == 1);
839 1.26 hannken
840 1.26 hannken printf("Fstrans state by mount:\n");
841 1.29 christos TAILQ_FOREACH(mp, &mountlist, mnt_list)
842 1.26 hannken fstrans_print_mount(mp, full == 1);
843 1.26 hannken }
844 1.26 hannken #endif /* defined(DDB) */
845