/
vfs_subr.c
2359 lines (2095 loc) · 52.8 KB
/
vfs_subr.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/* $OpenBSD: vfs_subr.c,v 1.301 2020/03/27 07:58:17 anton Exp $ */
/* $NetBSD: vfs_subr.c,v 1.53 1996/04/22 01:39:13 christos Exp $ */
/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)vfs_subr.c 8.13 (Berkeley) 4/18/94
*/
/*
* External virtual filesystem routines
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/sysctl.h>
#include <sys/mount.h>
#include <sys/time.h>
#include <sys/fcntl.h>
#include <sys/kernel.h>
#include <sys/conf.h>
#include <sys/vnode.h>
#include <sys/lock.h>
#include <sys/lockf.h>
#include <sys/stat.h>
#include <sys/acct.h>
#include <sys/namei.h>
#include <sys/ucred.h>
#include <sys/buf.h>
#include <sys/errno.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/syscallargs.h>
#include <sys/pool.h>
#include <sys/tree.h>
#include <sys/specdev.h>
#include <sys/atomic.h>
#include <netinet/in.h>
#include <uvm/uvm_extern.h>
#include <uvm/uvm_vnode.h>
#include "softraid.h"
void sr_quiesce(void);
enum vtype iftovt_tab[16] = {
VNON, VFIFO, VCHR, VNON, VDIR, VNON, VBLK, VNON,
VREG, VNON, VLNK, VNON, VSOCK, VNON, VNON, VBAD,
};
int vttoif_tab[9] = {
0, S_IFREG, S_IFDIR, S_IFBLK, S_IFCHR, S_IFLNK,
S_IFSOCK, S_IFIFO, S_IFMT,
};
int prtactive = 0; /* 1 => print out reclaim of active vnodes */
int suid_clear = 1; /* 1 => clear SUID / SGID on owner change */
/*
* Insq/Remq for the vnode usage lists.
*/
#define bufinsvn(bp, dp) LIST_INSERT_HEAD(dp, bp, b_vnbufs)
#define bufremvn(bp) { \
LIST_REMOVE(bp, b_vnbufs); \
LIST_NEXT(bp, b_vnbufs) = NOLIST; \
}
struct freelst vnode_hold_list; /* list of vnodes referencing buffers */
struct freelst vnode_free_list; /* vnode free list */
struct mntlist mountlist; /* mounted filesystem list */
void vclean(struct vnode *, int, struct proc *);
void insmntque(struct vnode *, struct mount *);
int getdevvp(dev_t, struct vnode **, enum vtype);
int vfs_hang_addrlist(struct mount *, struct netexport *,
struct export_args *);
int vfs_free_netcred(struct radix_node *, void *, u_int);
void vfs_free_addrlist(struct netexport *);
void vputonfreelist(struct vnode *);
int vflush_vnode(struct vnode *, void *);
int maxvnodes;
void vfs_unmountall(void);
#ifdef DEBUG
void printlockedvnodes(void);
#endif
struct pool vnode_pool;
struct pool uvm_vnode_pool;
static inline int rb_buf_compare(const struct buf *b1, const struct buf *b2);
RBT_GENERATE(buf_rb_bufs, buf, b_rbbufs, rb_buf_compare);
static inline int
rb_buf_compare(const struct buf *b1, const struct buf *b2)
{
if (b1->b_lblkno < b2->b_lblkno)
return(-1);
if (b1->b_lblkno > b2->b_lblkno)
return(1);
return(0);
}
/*
* Initialize the vnode management data structures.
*/
void
vntblinit(void)
{
/* buffer cache may need a vnode for each buffer */
maxvnodes = 2 * initialvnodes;
pool_init(&vnode_pool, sizeof(struct vnode), 0, IPL_NONE,
PR_WAITOK, "vnodes", NULL);
pool_init(&uvm_vnode_pool, sizeof(struct uvm_vnode), 0, IPL_NONE,
PR_WAITOK, "uvmvnodes", NULL);
TAILQ_INIT(&vnode_hold_list);
TAILQ_INIT(&vnode_free_list);
TAILQ_INIT(&mountlist);
/*
* Initialize the filesystem syncer.
*/
vn_initialize_syncerd();
#ifdef NFSSERVER
rn_init(sizeof(struct sockaddr_in));
#endif /* NFSSERVER */
}
/*
* Allocate a mount point.
*
* The returned mount point is marked as busy.
*/
struct mount *
vfs_mount_alloc(struct vnode *vp, struct vfsconf *vfsp)
{
struct mount *mp;
mp = malloc(sizeof(*mp), M_MOUNT, M_WAITOK|M_ZERO);
rw_init_flags(&mp->mnt_lock, "vfslock", RWL_IS_VNODE);
(void)vfs_busy(mp, VB_READ|VB_NOWAIT);
TAILQ_INIT(&mp->mnt_vnodelist);
mp->mnt_vnodecovered = vp;
atomic_inc_int(&vfsp->vfc_refcount);
mp->mnt_vfc = vfsp;
mp->mnt_op = vfsp->vfc_vfsops;
mp->mnt_flag = vfsp->vfc_flags;
strncpy(mp->mnt_stat.f_fstypename, vfsp->vfc_name, MFSNAMELEN);
return (mp);
}
/*
* Release a mount point.
*/
void
vfs_mount_free(struct mount *mp)
{
atomic_dec_int(&mp->mnt_vfc->vfc_refcount);
free(mp, M_MOUNT, sizeof(*mp));
}
/*
* Mark a mount point as busy. Used to synchronize access and to delay
* unmounting.
*
* Default behaviour is to attempt getting a READ lock and in case of an
* ongoing unmount, to wait for it to finish and then return failure.
*/
int
vfs_busy(struct mount *mp, int flags)
{
int rwflags = 0;
if (flags & VB_WRITE)
rwflags |= RW_WRITE;
else
rwflags |= RW_READ;
if (flags & VB_WAIT)
rwflags |= RW_SLEEPFAIL;
else
rwflags |= RW_NOSLEEP;
#ifdef WITNESS
if (flags & VB_DUPOK)
rwflags |= RW_DUPOK;
#endif
if (rw_enter(&mp->mnt_lock, rwflags))
return (EBUSY);
return (0);
}
/*
* Free a busy file system
*/
void
vfs_unbusy(struct mount *mp)
{
rw_exit(&mp->mnt_lock);
}
int
vfs_isbusy(struct mount *mp)
{
if (RWLOCK_OWNER(&mp->mnt_lock) > 0)
return (1);
else
return (0);
}
/*
* Lookup a filesystem type, and if found allocate and initialize
* a mount structure for it.
*
* Devname is usually updated by mount(8) after booting.
*/
int
vfs_rootmountalloc(char *fstypename, char *devname, struct mount **mpp)
{
struct vfsconf *vfsp;
struct mount *mp;
vfsp = vfs_byname(fstypename);
if (vfsp == NULL)
return (ENODEV);
mp = vfs_mount_alloc(NULLVP, vfsp);
mp->mnt_flag |= MNT_RDONLY;
mp->mnt_stat.f_mntonname[0] = '/';
copystr(devname, mp->mnt_stat.f_mntfromname, MNAMELEN, 0);
copystr(devname, mp->mnt_stat.f_mntfromspec, MNAMELEN, 0);
*mpp = mp;
return (0);
}
/*
* Lookup a mount point by filesystem identifier.
*/
struct mount *
vfs_getvfs(fsid_t *fsid)
{
struct mount *mp;
TAILQ_FOREACH(mp, &mountlist, mnt_list) {
if (mp->mnt_stat.f_fsid.val[0] == fsid->val[0] &&
mp->mnt_stat.f_fsid.val[1] == fsid->val[1]) {
return (mp);
}
}
return (NULL);
}
/*
* Get a new unique fsid
*/
void
vfs_getnewfsid(struct mount *mp)
{
static u_short xxxfs_mntid;
fsid_t tfsid;
int mtype;
mtype = mp->mnt_vfc->vfc_typenum;
mp->mnt_stat.f_fsid.val[0] = makedev(nblkdev + mtype, 0);
mp->mnt_stat.f_fsid.val[1] = mtype;
if (xxxfs_mntid == 0)
++xxxfs_mntid;
tfsid.val[0] = makedev(nblkdev + mtype, xxxfs_mntid);
tfsid.val[1] = mtype;
if (!TAILQ_EMPTY(&mountlist)) {
while (vfs_getvfs(&tfsid)) {
tfsid.val[0]++;
xxxfs_mntid++;
}
}
mp->mnt_stat.f_fsid.val[0] = tfsid.val[0];
}
/*
* Set vnode attributes to VNOVAL
*/
void
vattr_null(struct vattr *vap)
{
vap->va_type = VNON;
/*
* Don't get fancy: u_quad_t = u_int = VNOVAL leaves the u_quad_t
* with 2^31-1 instead of 2^64-1. Just write'm out and let
* the compiler do its job.
*/
vap->va_mode = VNOVAL;
vap->va_nlink = VNOVAL;
vap->va_uid = VNOVAL;
vap->va_gid = VNOVAL;
vap->va_fsid = VNOVAL;
vap->va_fileid = VNOVAL;
vap->va_size = VNOVAL;
vap->va_blocksize = VNOVAL;
vap->va_atime.tv_sec = VNOVAL;
vap->va_atime.tv_nsec = VNOVAL;
vap->va_mtime.tv_sec = VNOVAL;
vap->va_mtime.tv_nsec = VNOVAL;
vap->va_ctime.tv_sec = VNOVAL;
vap->va_ctime.tv_nsec = VNOVAL;
vap->va_gen = VNOVAL;
vap->va_flags = VNOVAL;
vap->va_rdev = VNOVAL;
vap->va_bytes = VNOVAL;
vap->va_filerev = VNOVAL;
vap->va_vaflags = 0;
}
/*
* Routines having to do with the management of the vnode table.
*/
long numvnodes;
/*
* Return the next vnode from the free list.
*/
int
getnewvnode(enum vtagtype tag, struct mount *mp, const struct vops *vops,
struct vnode **vpp)
{
struct proc *p = curproc;
struct freelst *listhd;
static int toggle;
struct vnode *vp;
int s;
/*
* allow maxvnodes to increase if the buffer cache itself
* is big enough to justify it. (we don't shrink it ever)
*/
maxvnodes = maxvnodes < bcstats.numbufs ? bcstats.numbufs
: maxvnodes;
/*
* We must choose whether to allocate a new vnode or recycle an
* existing one. The criterion for allocating a new one is that
* the total number of vnodes is less than the number desired or
* there are no vnodes on either free list. Generally we only
* want to recycle vnodes that have no buffers associated with
* them, so we look first on the vnode_free_list. If it is empty,
* we next consider vnodes with referencing buffers on the
* vnode_hold_list. The toggle ensures that half the time we
* will use a buffer from the vnode_hold_list, and half the time
* we will allocate a new one unless the list has grown to twice
* the desired size. We are reticent to recycle vnodes from the
* vnode_hold_list because we will lose the identity of all its
* referencing buffers.
*/
toggle ^= 1;
if (numvnodes / 2 > maxvnodes)
toggle = 0;
s = splbio();
if ((numvnodes < maxvnodes) ||
((TAILQ_FIRST(listhd = &vnode_free_list) == NULL) &&
((TAILQ_FIRST(listhd = &vnode_hold_list) == NULL) || toggle))) {
splx(s);
vp = pool_get(&vnode_pool, PR_WAITOK | PR_ZERO);
vp->v_uvm = pool_get(&uvm_vnode_pool, PR_WAITOK | PR_ZERO);
vp->v_uvm->u_vnode = vp;
RBT_INIT(buf_rb_bufs, &vp->v_bufs_tree);
cache_tree_init(&vp->v_nc_tree);
TAILQ_INIT(&vp->v_cache_dst);
numvnodes++;
} else {
TAILQ_FOREACH(vp, listhd, v_freelist) {
if (VOP_ISLOCKED(vp) == 0)
break;
}
/*
* Unless this is a bad time of the month, at most
* the first NCPUS items on the free list are
* locked, so this is close enough to being empty.
*/
if (vp == NULL) {
splx(s);
tablefull("vnode");
*vpp = 0;
return (ENFILE);
}
#ifdef DIAGNOSTIC
if (vp->v_usecount) {
vprint("free vnode", vp);
panic("free vnode isn't");
}
#endif
TAILQ_REMOVE(listhd, vp, v_freelist);
vp->v_bioflag &= ~VBIOONFREELIST;
splx(s);
if (vp->v_type != VBAD)
vgonel(vp, p);
#ifdef DIAGNOSTIC
if (vp->v_data) {
vprint("cleaned vnode", vp);
panic("cleaned vnode isn't");
}
s = splbio();
if (vp->v_numoutput)
panic("Clean vnode has pending I/O's");
splx(s);
#endif
vp->v_flag = 0;
vp->v_socket = 0;
}
cache_purge(vp);
vp->v_type = VNON;
vp->v_tag = tag;
vp->v_op = vops;
insmntque(vp, mp);
*vpp = vp;
vp->v_usecount = 1;
vp->v_data = 0;
return (0);
}
/*
* Move a vnode from one mount queue to another.
*/
void
insmntque(struct vnode *vp, struct mount *mp)
{
/*
* Delete from old mount point vnode list, if on one.
*/
if (vp->v_mount != NULL)
TAILQ_REMOVE(&vp->v_mount->mnt_vnodelist, vp, v_mntvnodes);
/*
* Insert into list of vnodes for the new mount point, if available.
*/
if ((vp->v_mount = mp) != NULL)
TAILQ_INSERT_TAIL(&mp->mnt_vnodelist, vp, v_mntvnodes);
}
/*
* Create a vnode for a block device.
* Used for root filesystem, argdev, and swap areas.
* Also used for memory file system special devices.
*/
int
bdevvp(dev_t dev, struct vnode **vpp)
{
return (getdevvp(dev, vpp, VBLK));
}
/*
* Create a vnode for a character device.
* Used for console handling.
*/
int
cdevvp(dev_t dev, struct vnode **vpp)
{
return (getdevvp(dev, vpp, VCHR));
}
/*
* Create a vnode for a device.
* Used by bdevvp (block device) for root file system etc.,
* and by cdevvp (character device) for console.
*/
int
getdevvp(dev_t dev, struct vnode **vpp, enum vtype type)
{
struct vnode *vp;
struct vnode *nvp;
int error;
if (dev == NODEV) {
*vpp = NULLVP;
return (0);
}
error = getnewvnode(VT_NON, NULL, &spec_vops, &nvp);
if (error) {
*vpp = NULLVP;
return (error);
}
vp = nvp;
vp->v_type = type;
if ((nvp = checkalias(vp, dev, NULL)) != 0) {
vput(vp);
vp = nvp;
}
if (vp->v_type == VCHR && cdevsw[major(vp->v_rdev)].d_type == D_TTY)
vp->v_flag |= VISTTY;
*vpp = vp;
return (0);
}
/*
* Check to see if the new vnode represents a special device
* for which we already have a vnode (either because of
* bdevvp() or because of a different vnode representing
* the same block device). If such an alias exists, deallocate
* the existing contents and return the aliased vnode. The
* caller is responsible for filling it with its new contents.
*/
struct vnode *
checkalias(struct vnode *nvp, dev_t nvp_rdev, struct mount *mp)
{
struct proc *p = curproc;
struct vnode *vp;
struct vnodechain *vchain;
if (nvp->v_type != VBLK && nvp->v_type != VCHR)
return (NULLVP);
vchain = &speclisth[SPECHASH(nvp_rdev)];
loop:
SLIST_FOREACH(vp, vchain, v_specnext) {
if (nvp_rdev != vp->v_rdev || nvp->v_type != vp->v_type) {
continue;
}
/*
* Alias, but not in use, so flush it out.
*/
if (vp->v_usecount == 0) {
vgonel(vp, p);
goto loop;
}
if (vget(vp, LK_EXCLUSIVE)) {
goto loop;
}
break;
}
/*
* Common case is actually in the if statement
*/
if (vp == NULL || !(vp->v_tag == VT_NON && vp->v_type == VBLK)) {
nvp->v_specinfo = malloc(sizeof(struct specinfo), M_VNODE,
M_WAITOK);
nvp->v_rdev = nvp_rdev;
nvp->v_hashchain = vchain;
nvp->v_specmountpoint = NULL;
nvp->v_speclockf = NULL;
nvp->v_specbitmap = NULL;
if (nvp->v_type == VCHR &&
(cdevsw[major(nvp_rdev)].d_flags & D_CLONE) &&
(minor(nvp_rdev) >> CLONE_SHIFT == 0)) {
if (vp != NULLVP)
nvp->v_specbitmap = vp->v_specbitmap;
else
nvp->v_specbitmap = malloc(CLONE_MAPSZ,
M_VNODE, M_WAITOK | M_ZERO);
}
SLIST_INSERT_HEAD(vchain, nvp, v_specnext);
if (vp != NULLVP) {
nvp->v_flag |= VALIASED;
vp->v_flag |= VALIASED;
vput(vp);
}
return (NULLVP);
}
/*
* This code is the uncommon case. It is called in case
* we found an alias that was VT_NON && vtype of VBLK
* This means we found a block device that was created
* using bdevvp.
* An example of such a vnode is the root partition device vnode
* created in ffs_mountroot.
*
* The vnodes created by bdevvp should not be aliased (why?).
*/
VOP_UNLOCK(vp);
vclean(vp, 0, p);
vp->v_op = nvp->v_op;
vp->v_tag = nvp->v_tag;
nvp->v_type = VNON;
insmntque(vp, mp);
return (vp);
}
/*
* Grab a particular vnode from the free list, increment its
* reference count and lock it. If the vnode lock bit is set,
* the vnode is being eliminated in vgone. In that case, we
* cannot grab it, so the process is awakened when the
* transition is completed, and an error code is returned to
* indicate that the vnode is no longer usable, possibly
* having been changed to a new file system type.
*/
int
vget(struct vnode *vp, int flags)
{
int error, s, onfreelist;
/*
* If the vnode is in the process of being cleaned out for
* another use, we wait for the cleaning to finish and then
* return failure. Cleaning is determined by checking that
* the VXLOCK flag is set.
*/
if (vp->v_flag & VXLOCK) {
if (flags & LK_NOWAIT) {
return (EBUSY);
}
vp->v_flag |= VXWANT;
tsleep_nsec(vp, PINOD, "vget", INFSLP);
return (ENOENT);
}
onfreelist = vp->v_bioflag & VBIOONFREELIST;
if (vp->v_usecount == 0 && onfreelist) {
s = splbio();
if (vp->v_holdcnt > 0)
TAILQ_REMOVE(&vnode_hold_list, vp, v_freelist);
else
TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
vp->v_bioflag &= ~VBIOONFREELIST;
splx(s);
}
vp->v_usecount++;
if (flags & LK_TYPE_MASK) {
if ((error = vn_lock(vp, flags)) != 0) {
vp->v_usecount--;
if (vp->v_usecount == 0 && onfreelist)
vputonfreelist(vp);
}
return (error);
}
return (0);
}
/* Vnode reference. */
void
vref(struct vnode *vp)
{
#ifdef DIAGNOSTIC
if (vp->v_usecount == 0)
panic("vref used where vget required");
if (vp->v_type == VNON)
panic("vref on a VNON vnode");
#endif
vp->v_usecount++;
}
void
vputonfreelist(struct vnode *vp)
{
int s;
struct freelst *lst;
s = splbio();
#ifdef DIAGNOSTIC
if (vp->v_usecount != 0)
panic("Use count is not zero!");
/*
* If the hold count is still positive, one or many threads could still
* be waiting on the vnode lock inside uvn_io().
*/
if (vp->v_holdcnt == 0 && vp->v_lockcount != 0)
panic("%s: lock count is not zero", __func__);
if (vp->v_bioflag & VBIOONFREELIST) {
vprint("vnode already on free list: ", vp);
panic("vnode already on free list");
}
#endif
vp->v_bioflag |= VBIOONFREELIST;
vp->v_bioflag &= ~VBIOERROR;
if (vp->v_holdcnt > 0)
lst = &vnode_hold_list;
else
lst = &vnode_free_list;
if (vp->v_type == VBAD)
TAILQ_INSERT_HEAD(lst, vp, v_freelist);
else
TAILQ_INSERT_TAIL(lst, vp, v_freelist);
splx(s);
}
/*
* vput(), just unlock and vrele()
*/
void
vput(struct vnode *vp)
{
struct proc *p = curproc;
#ifdef DIAGNOSTIC
if (vp == NULL)
panic("vput: null vp");
#endif
#ifdef DIAGNOSTIC
if (vp->v_usecount == 0) {
vprint("vput: bad ref count", vp);
panic("vput: ref cnt");
}
#endif
vp->v_usecount--;
KASSERT(vp->v_usecount > 0 || vp->v_uvcount == 0);
if (vp->v_usecount > 0) {
VOP_UNLOCK(vp);
return;
}
#ifdef DIAGNOSTIC
if (vp->v_writecount != 0) {
vprint("vput: bad writecount", vp);
panic("vput: v_writecount != 0");
}
#endif
VOP_INACTIVE(vp, p);
if (vp->v_usecount == 0 && !(vp->v_bioflag & VBIOONFREELIST))
vputonfreelist(vp);
}
/*
* Vnode release - use for active VNODES.
* If count drops to zero, call inactive routine and return to freelist.
* Returns 0 if it did not sleep.
*/
int
vrele(struct vnode *vp)
{
struct proc *p = curproc;
#ifdef DIAGNOSTIC
if (vp == NULL)
panic("vrele: null vp");
#endif
#ifdef DIAGNOSTIC
if (vp->v_usecount == 0) {
vprint("vrele: bad ref count", vp);
panic("vrele: ref cnt");
}
#endif
vp->v_usecount--;
if (vp->v_usecount > 0) {
return (0);
}
#ifdef DIAGNOSTIC
if (vp->v_writecount != 0) {
vprint("vrele: bad writecount", vp);
panic("vrele: v_writecount != 0");
}
#endif
if (vn_lock(vp, LK_EXCLUSIVE)) {
#ifdef DIAGNOSTIC
vprint("vrele: cannot lock", vp);
#endif
return (1);
}
VOP_INACTIVE(vp, p);
if (vp->v_usecount == 0 && !(vp->v_bioflag & VBIOONFREELIST))
vputonfreelist(vp);
return (1);
}
/* Page or buffer structure gets a reference. */
void
vhold(struct vnode *vp)
{
/*
* If it is on the freelist and the hold count is currently
* zero, move it to the hold list.
*/
if ((vp->v_bioflag & VBIOONFREELIST) &&
vp->v_holdcnt == 0 && vp->v_usecount == 0) {
TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
TAILQ_INSERT_TAIL(&vnode_hold_list, vp, v_freelist);
}
vp->v_holdcnt++;
}
/* Lose interest in a vnode. */
void
vdrop(struct vnode *vp)
{
#ifdef DIAGNOSTIC
if (vp->v_holdcnt == 0)
panic("vdrop: zero holdcnt");
#endif
vp->v_holdcnt--;
/*
* If it is on the holdlist and the hold count drops to
* zero, move it to the free list.
*/
if ((vp->v_bioflag & VBIOONFREELIST) &&
vp->v_holdcnt == 0 && vp->v_usecount == 0) {
TAILQ_REMOVE(&vnode_hold_list, vp, v_freelist);
TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
}
}
/*
* Remove any vnodes in the vnode table belonging to mount point mp.
*
* If MNT_NOFORCE is specified, there should not be any active ones,
* return error if any are found (nb: this is a user error, not a
* system error). If MNT_FORCE is specified, detach any active vnodes
* that are found.
*/
#ifdef DEBUG
int busyprt = 0; /* print out busy vnodes */
struct ctldebug debug1 = { "busyprt", &busyprt };
#endif
int
vfs_mount_foreach_vnode(struct mount *mp,
int (*func)(struct vnode *, void *), void *arg) {
struct vnode *vp, *nvp;
int error = 0;
loop:
TAILQ_FOREACH_SAFE(vp , &mp->mnt_vnodelist, v_mntvnodes, nvp) {
if (vp->v_mount != mp)
goto loop;
error = func(vp, arg);
if (error != 0)
break;
}
return (error);
}
struct vflush_args {
struct vnode *skipvp;
int busy;
int flags;
};
int
vflush_vnode(struct vnode *vp, void *arg)
{
struct vflush_args *va = arg;
struct proc *p = curproc;
if (vp == va->skipvp) {
return (0);
}
if ((va->flags & SKIPSYSTEM) && (vp->v_flag & VSYSTEM)) {
return (0);
}
/*
* If WRITECLOSE is set, only flush out regular file
* vnodes open for writing.
*/
if ((va->flags & WRITECLOSE) &&
(vp->v_writecount == 0 || vp->v_type != VREG)) {
return (0);
}
/*
* With v_usecount == 0, all we need to do is clear
* out the vnode data structures and we are done.
*/
if (vp->v_usecount == 0) {
vgonel(vp, p);
return (0);
}
/*
* If FORCECLOSE is set, forcibly close the vnode.
* For block or character devices, revert to an
* anonymous device. For all other files, just kill them.
*/
if (va->flags & FORCECLOSE) {
if (vp->v_type != VBLK && vp->v_type != VCHR) {
vgonel(vp, p);
} else {
vclean(vp, 0, p);
vp->v_op = &spec_vops;
insmntque(vp, NULL);
}
return (0);
}
/*
* If set, this is allowed to ignore vnodes which don't
* have changes pending to disk.
* XXX Might be nice to check per-fs "inode" flags, but
* generally the filesystem is sync'd already, right?
*/
if ((va->flags & IGNORECLEAN) &&
LIST_EMPTY(&vp->v_dirtyblkhd))
return (0);
#ifdef DEBUG
if (busyprt)
vprint("vflush: busy vnode", vp);
#endif
va->busy++;
return (0);
}
int
vflush(struct mount *mp, struct vnode *skipvp, int flags)
{
struct vflush_args va;
va.skipvp = skipvp;
va.busy = 0;
va.flags = flags;
vfs_mount_foreach_vnode(mp, vflush_vnode, &va);
if (va.busy)
return (EBUSY);
return (0);
}
/*
* Disassociate the underlying file system from a vnode.
*/
void
vclean(struct vnode *vp, int flags, struct proc *p)
{
int active;
/*
* Check to see if the vnode is in use.
* If so we have to reference it before we clean it out
* so that its count cannot fall to zero and generate a
* race against ourselves to recycle it.
*/
if ((active = vp->v_usecount) != 0)
vp->v_usecount++;
/*
* Prevent the vnode from being recycled or
* brought into use while we clean it out.
*/
if (vp->v_flag & VXLOCK)