2 * Copyright (c) 2004,2013-2019 The DragonFly Project. All rights reserved.
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
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12 * notice, this list of conditions and the following disclaimer.
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34 * Copyright (c) 1989, 1993
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36 * (c) UNIX System Laboratories, Inc.
37 * All or some portions of this file are derived from material licensed
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51 * may be used to endorse or promote products derived from this software
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56 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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61 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
68 * External virtual filesystem routines
71 #include <sys/param.h>
72 #include <sys/systm.h>
73 #include <sys/kernel.h>
74 #include <sys/malloc.h>
75 #include <sys/mount.h>
77 #include <sys/vnode.h>
78 #include <sys/spinlock2.h>
79 #include <sys/eventhandler.h>
80 #include <sys/kthread.h>
81 #include <sys/sysctl.h>
83 #include <machine/limits.h>
86 #include <vm/vm_object.h>
88 struct mountscan_info {
89 TAILQ_ENTRY(mountscan_info) msi_entry;
91 struct mount *msi_node;
94 struct vmntvnodescan_info {
95 TAILQ_ENTRY(vmntvnodescan_info) entry;
104 mount_cmp(struct mount *mnt1, struct mount *mnt2)
106 if (mnt1->mnt_stat.f_fsid.val[0] < mnt2->mnt_stat.f_fsid.val[0])
108 if (mnt1->mnt_stat.f_fsid.val[0] > mnt2->mnt_stat.f_fsid.val[0])
110 if (mnt1->mnt_stat.f_fsid.val[1] < mnt2->mnt_stat.f_fsid.val[1])
112 if (mnt1->mnt_stat.f_fsid.val[1] > mnt2->mnt_stat.f_fsid.val[1])
118 mount_fsid_cmp(fsid_t *fsid, struct mount *mnt)
120 if (fsid->val[0] < mnt->mnt_stat.f_fsid.val[0])
122 if (fsid->val[0] > mnt->mnt_stat.f_fsid.val[0])
124 if (fsid->val[1] < mnt->mnt_stat.f_fsid.val[1])
126 if (fsid->val[1] > mnt->mnt_stat.f_fsid.val[1])
131 RB_HEAD(mount_rb_tree, mount);
132 RB_PROTOTYPEX(mount_rb_tree, FSID, mount, mnt_node, mount_cmp, fsid_t *);
133 RB_GENERATE(mount_rb_tree, mount, mnt_node, mount_cmp);
134 RB_GENERATE_XLOOKUP(mount_rb_tree, FSID, mount, mnt_node,
135 mount_fsid_cmp, fsid_t *);
137 static int vnlru_nowhere = 0;
138 SYSCTL_INT(_debug, OID_AUTO, vnlru_nowhere, CTLFLAG_RD,
140 "Number of times the vnlru process ran without success");
143 static struct lwkt_token mntid_token;
144 static struct mount dummymount;
146 /* note: mountlist exported to pstat */
147 struct mntlist mountlist = TAILQ_HEAD_INITIALIZER(mountlist);
148 struct mount_rb_tree mounttree = RB_INITIALIZER(dev_tree_mounttree);
149 static TAILQ_HEAD(,mountscan_info) mountscan_list;
150 static struct lwkt_token mountlist_token;
152 static TAILQ_HEAD(,bio_ops) bio_ops_list = TAILQ_HEAD_INITIALIZER(bio_ops_list);
155 * Called from vfsinit()
160 lwkt_token_init(&mountlist_token, "mntlist");
161 lwkt_token_init(&mntid_token, "mntid");
162 TAILQ_INIT(&mountscan_list);
163 mount_init(&dummymount);
164 dummymount.mnt_flag |= MNT_RDONLY;
165 dummymount.mnt_kern_flag |= MNTK_ALL_MPSAFE;
169 * Support function called to remove a vnode from the mountlist and
170 * deal with side effects for scans in progress.
172 * Target mnt_token is held on call.
175 vremovevnodemnt(struct vnode *vp)
177 struct vmntvnodescan_info *info;
178 struct mount *mp = vp->v_mount;
180 TAILQ_FOREACH(info, &mp->mnt_vnodescan_list, entry) {
182 info->vp = TAILQ_NEXT(vp, v_nmntvnodes);
184 TAILQ_REMOVE(&vp->v_mount->mnt_nvnodelist, vp, v_nmntvnodes);
188 * Allocate a new vnode and associate it with a tag, mount point, and
191 * A VX locked and refd vnode is returned. The caller should setup the
192 * remaining fields and vx_put() or, if he wishes to leave a vref,
193 * vx_unlock() the vnode.
196 getnewvnode(enum vtagtype tag, struct mount *mp,
197 struct vnode **vpp, int lktimeout, int lkflags)
201 KKASSERT(mp != NULL);
203 vp = allocvnode(lktimeout, lkflags);
208 * By default the vnode is assigned the mount point's normal
211 vp->v_ops = &mp->mnt_vn_use_ops;
212 vp->v_pbuf_count = nswbuf_kva / NSWBUF_SPLIT;
215 * Placing the vnode on the mount point's queue makes it visible.
216 * VNON prevents it from being messed with, however.
221 * A VX locked & refd vnode is returned.
228 * This function creates vnodes with special operations vectors. The
229 * mount point is optional.
231 * This routine is being phased out but is still used by vfs_conf to
232 * create vnodes for devices prior to the root mount (with mp == NULL).
235 getspecialvnode(enum vtagtype tag, struct mount *mp,
236 struct vop_ops **ops,
237 struct vnode **vpp, int lktimeout, int lkflags)
241 vp = allocvnode(lktimeout, lkflags);
250 * Placing the vnode on the mount point's queue makes it visible.
251 * VNON prevents it from being messed with, however.
256 * A VX locked & refd vnode is returned.
263 * Interlock against an unmount, return 0 on success, non-zero on failure.
265 * The passed flag may be 0 or LK_NOWAIT and is only used if an unmount
268 * If no unmount is in-progress LK_NOWAIT is ignored. No other flag bits
269 * are used. A shared locked will be obtained and the filesystem will not
270 * be unmountable until the lock is released.
273 vfs_busy(struct mount *mp, int flags)
277 atomic_add_int(&mp->mnt_refs, 1);
278 lwkt_gettoken(&mp->mnt_token);
279 if (mp->mnt_kern_flag & MNTK_UNMOUNT) {
280 if (flags & LK_NOWAIT) {
281 lwkt_reltoken(&mp->mnt_token);
282 atomic_add_int(&mp->mnt_refs, -1);
285 /* XXX not MP safe */
286 mp->mnt_kern_flag |= MNTK_MWAIT;
289 * Since all busy locks are shared except the exclusive
290 * lock granted when unmounting, the only place that a
291 * wakeup needs to be done is at the release of the
292 * exclusive lock at the end of dounmount.
294 * WARNING! mp can potentially go away once we release
297 tsleep((caddr_t)mp, 0, "vfs_busy", 0);
298 lwkt_reltoken(&mp->mnt_token);
299 atomic_add_int(&mp->mnt_refs, -1);
303 if (lockmgr(&mp->mnt_lock, lkflags))
304 panic("vfs_busy: unexpected lock failure");
305 lwkt_reltoken(&mp->mnt_token);
310 * Free a busy filesystem.
312 * Once refs is decremented the mount point can potentially get ripped
313 * out from under us, but we want to clean up our refs before unlocking
314 * so do a hold/drop around the whole mess.
316 * This is not in the critical path (I hope).
319 vfs_unbusy(struct mount *mp)
322 atomic_add_int(&mp->mnt_refs, -1);
323 lockmgr(&mp->mnt_lock, LK_RELEASE);
328 * Lookup a filesystem type, and if found allocate and initialize
329 * a mount structure for it.
331 * Devname is usually updated by mount(8) after booting.
334 vfs_rootmountalloc(char *fstypename, char *devname, struct mount **mpp)
336 struct vfsconf *vfsp;
339 if (fstypename == NULL)
342 vfsp = vfsconf_find_by_name(fstypename);
345 mp = kmalloc(sizeof(struct mount), M_MOUNT, M_WAITOK | M_ZERO);
347 lockinit(&mp->mnt_lock, "vfslock", VLKTIMEOUT, 0);
351 mp->mnt_op = vfsp->vfc_vfsops;
352 mp->mnt_pbuf_count = nswbuf_kva / NSWBUF_SPLIT;
353 vfsp->vfc_refcount++;
354 mp->mnt_stat.f_type = vfsp->vfc_typenum;
355 mp->mnt_flag |= MNT_RDONLY;
356 mp->mnt_flag |= vfsp->vfc_flags & MNT_VISFLAGMASK;
357 strncpy(mp->mnt_stat.f_fstypename, vfsp->vfc_name, MFSNAMELEN);
358 copystr(devname, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 0);
361 * Pre-set MPSAFE flags for VFS_MOUNT() call.
363 if (vfsp->vfc_flags & VFCF_MPSAFE)
364 mp->mnt_kern_flag |= MNTK_ALL_MPSAFE;
372 * Basic mount structure initialization
375 mount_init(struct mount *mp)
377 lockinit(&mp->mnt_lock, "vfslock", hz*5, 0);
378 lwkt_token_init(&mp->mnt_token, "permnt");
380 TAILQ_INIT(&mp->mnt_vnodescan_list);
381 TAILQ_INIT(&mp->mnt_nvnodelist);
382 TAILQ_INIT(&mp->mnt_reservedvnlist);
383 TAILQ_INIT(&mp->mnt_jlist);
384 mp->mnt_nvnodelistsize = 0;
386 mp->mnt_hold = 1; /* hold for umount last drop */
387 mp->mnt_iosize_max = MAXPHYS;
388 vn_syncer_thr_create(mp);
392 mount_hold(struct mount *mp)
394 atomic_add_int(&mp->mnt_hold, 1);
398 mount_drop(struct mount *mp)
400 if (atomic_fetchadd_int(&mp->mnt_hold, -1) == 1) {
401 KKASSERT(mp->mnt_refs == 0);
407 * Lookup a mount point by filesystem identifier.
409 * If not NULL, the returned mp is held and the caller is expected to drop
410 * it via mount_drop().
413 vfs_getvfs(fsid_t *fsid)
417 lwkt_gettoken_shared(&mountlist_token);
418 mp = mount_rb_tree_RB_LOOKUP_FSID(&mounttree, fsid);
421 lwkt_reltoken(&mountlist_token);
426 * Generate a FSID based on the mountpt. The FSID will be adjusted to avoid
427 * collisions when the mount is added to mountlist.
429 * May only be called prior to the mount succeeding.
433 * Get a new unique fsid. Try to make its val[0] unique, since this value
434 * will be used to create fake device numbers for stat(). Also try (but
435 * not so hard) make its val[0] unique mod 2^16, since some emulators only
436 * support 16-bit device numbers. We end up with unique val[0]'s for the
437 * first 2^16 calls and unique val[0]'s mod 2^16 for the first 2^8 calls.
440 vfs_getnewfsid(struct mount *mp)
448 mtype = mp->mnt_vfc->vfc_typenum;
449 tfsid.val[1] = mtype;
450 error = cache_fullpath(NULL, &mp->mnt_ncmounton, NULL,
451 &retbuf, &freebuf, 0);
453 tfsid.val[0] = makeudev(255, 0);
455 tfsid.val[0] = makeudev(255,
456 iscsi_crc32(retbuf, strlen(retbuf)) &
458 kfree(freebuf, M_TEMP);
460 mp->mnt_stat.f_fsid.val[0] = tfsid.val[0];
461 mp->mnt_stat.f_fsid.val[1] = tfsid.val[1];
465 * Set the FSID for a new mount point to the template.
467 * The FSID will be adjusted to avoid collisions when the mount is
468 * added to mountlist.
470 * May only be called prior to the mount succeeding.
473 vfs_setfsid(struct mount *mp, fsid_t *template)
475 bzero(&mp->mnt_stat.f_fsid, sizeof(mp->mnt_stat.f_fsid));
480 lwkt_gettoken(&mntid_token);
482 mptmp = vfs_getvfs(template);
488 lwkt_reltoken(&mntid_token);
490 mp->mnt_stat.f_fsid = *template;
494 * This routine is called when we have too many vnodes. It attempts
495 * to free <count> vnodes and will potentially free vnodes that still
496 * have VM backing store (VM backing store is typically the cause
497 * of a vnode blowout so we want to do this). Therefore, this operation
498 * is not considered cheap.
500 * A number of conditions may prevent a vnode from being reclaimed.
501 * the buffer cache may have references on the vnode, a directory
502 * vnode may still have references due to the namei cache representing
503 * underlying files, or the vnode may be in active use. It is not
504 * desireable to reuse such vnodes. These conditions may cause the
505 * number of vnodes to reach some minimum value regardless of what
506 * you set kern.maxvnodes to. Do not set kern.maxvnodes too low.
510 * Attempt to recycle vnodes in a context that is always safe to block.
511 * Calling vlrurecycle() from the bowels of file system code has some
512 * interesting deadlock problems.
514 static struct thread *vnlruthread;
519 struct thread *td = curthread;
521 EVENTHANDLER_REGISTER(shutdown_pre_sync, shutdown_kproc, td,
525 int ncachedandinactive;
527 kproc_suspend_loop();
530 * Try to free some vnodes if we have too many. Trigger based
531 * on potentially freeable vnodes but calculate the count
532 * based on total vnodes.
534 * (long) -> deal with 64 bit machines, intermediate overflow
536 synchronizevnodecount();
537 ncachedandinactive = countcachedandinactivevnodes();
538 if (numvnodes >= maxvnodes * 9 / 10 &&
539 ncachedandinactive >= maxvnodes * 5 / 10) {
540 int count = numvnodes - maxvnodes * 9 / 10;
542 if (count > (ncachedandinactive) / 100)
543 count = (ncachedandinactive) / 100;
546 freesomevnodes(count);
550 * Do non-critical-path (more robust) cache cleaning,
551 * even if vnode counts are nominal, to try to avoid
552 * having to do it in the critical path.
557 * Nothing to do if most of our vnodes are already on
560 synchronizevnodecount();
561 ncachedandinactive = countcachedandinactivevnodes();
562 if (numvnodes <= maxvnodes * 9 / 10 ||
563 ncachedandinactive <= maxvnodes * 5 / 10) {
564 tsleep(vnlruthread, 0, "vlruwt", hz);
571 * MOUNTLIST FUNCTIONS
575 * mountlist_insert (MP SAFE)
577 * Add a new mount point to the mount list. Filesystem should attempt to
578 * supply a unique fsid but if a duplicate occurs adjust the fsid to ensure
582 mountlist_insert(struct mount *mp, int how)
584 int lim = 0x01000000;
586 lwkt_gettoken(&mountlist_token);
587 if (how == MNTINS_FIRST)
588 TAILQ_INSERT_HEAD(&mountlist, mp, mnt_list);
590 TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
591 while (mount_rb_tree_RB_INSERT(&mounttree, mp)) {
595 * minor device mask: 0xFFFF00FF
597 val = mp->mnt_stat.f_fsid.val[0];
598 val = ((val & 0xFFFF0000) >> 8) | (val & 0x000000FF);
600 val = ((val << 8) & 0xFFFF0000) | (val & 0x000000FF);
601 mp->mnt_stat.f_fsid.val[0] = val;
604 mp->mnt_stat.f_fsid.val[1] += 0x0100;
605 kprintf("mountlist_insert: fsid collision, "
606 "too many mounts\n");
609 lwkt_reltoken(&mountlist_token);
613 * mountlist_interlock (MP SAFE)
615 * Execute the specified interlock function with the mountlist token
616 * held. The function will be called in a serialized fashion verses
617 * other functions called through this mechanism.
619 * The function is expected to be very short-lived.
622 mountlist_interlock(int (*callback)(struct mount *), struct mount *mp)
626 lwkt_gettoken(&mountlist_token);
627 error = callback(mp);
628 lwkt_reltoken(&mountlist_token);
633 * mountlist_boot_getfirst (DURING BOOT ONLY)
635 * This function returns the first mount on the mountlist, which is
636 * expected to be the root mount. Since no interlocks are obtained
637 * this function is only safe to use during booting.
641 mountlist_boot_getfirst(void)
643 return(TAILQ_FIRST(&mountlist));
647 * mountlist_remove (MP SAFE)
649 * Remove a node from the mountlist. If this node is the next scan node
650 * for any active mountlist scans, the active mountlist scan will be
651 * adjusted to skip the node, thus allowing removals during mountlist
655 mountlist_remove(struct mount *mp)
657 struct mountscan_info *msi;
659 lwkt_gettoken(&mountlist_token);
660 TAILQ_FOREACH(msi, &mountscan_list, msi_entry) {
661 if (msi->msi_node == mp) {
662 if (msi->msi_how & MNTSCAN_FORWARD)
663 msi->msi_node = TAILQ_NEXT(mp, mnt_list);
665 msi->msi_node = TAILQ_PREV(mp, mntlist,
669 TAILQ_REMOVE(&mountlist, mp, mnt_list);
670 mount_rb_tree_RB_REMOVE(&mounttree, mp);
671 lwkt_reltoken(&mountlist_token);
675 * mountlist_exists (MP SAFE)
677 * Checks if a node exists in the mountlist.
678 * This function is mainly used by VFS quota code to check if a
679 * cached nullfs struct mount pointer is still valid at use time
681 * FIXME: there is no warranty the mp passed to that function
682 * will be the same one used by VFS_ACCOUNT() later
685 mountlist_exists(struct mount *mp)
690 lwkt_gettoken_shared(&mountlist_token);
691 TAILQ_FOREACH(lmp, &mountlist, mnt_list) {
697 lwkt_reltoken(&mountlist_token);
705 * Safely scan the mount points on the mount list. Each mountpoint
706 * is held across the callback. The callback is responsible for
707 * acquiring any further tokens or locks.
709 * Unless otherwise specified each mount point will be busied prior to the
710 * callback and unbusied afterwords. The callback may safely remove any
711 * mount point without interfering with the scan. If the current callback
712 * mount is removed the scanner will not attempt to unbusy it.
714 * If a mount node cannot be busied it is silently skipped.
716 * The callback return value is aggregated and a total is returned. A return
717 * value of < 0 is not aggregated and will terminate the scan.
719 * MNTSCAN_FORWARD - the mountlist is scanned in the forward direction
720 * MNTSCAN_REVERSE - the mountlist is scanned in reverse
721 * MNTSCAN_NOBUSY - the scanner will make the callback without busying
724 * NOTE: mountlist_token is not held across the callback.
727 mountlist_scan(int (*callback)(struct mount *, void *), void *data, int how)
729 struct mountscan_info info;
734 lwkt_gettoken(&mountlist_token);
736 info.msi_node = NULL; /* paranoia */
737 TAILQ_INSERT_TAIL(&mountscan_list, &info, msi_entry);
738 lwkt_reltoken(&mountlist_token);
741 lwkt_gettoken_shared(&mountlist_token);
743 if (how & MNTSCAN_FORWARD) {
744 info.msi_node = TAILQ_FIRST(&mountlist);
745 while ((mp = info.msi_node) != NULL) {
747 if (how & MNTSCAN_NOBUSY) {
748 lwkt_reltoken(&mountlist_token);
749 count = callback(mp, data);
750 lwkt_gettoken_shared(&mountlist_token);
751 } else if (vfs_busy(mp, LK_NOWAIT) == 0) {
752 lwkt_reltoken(&mountlist_token);
753 count = callback(mp, data);
754 lwkt_gettoken_shared(&mountlist_token);
755 if (mp == info.msi_node)
764 if (mp == info.msi_node)
765 info.msi_node = TAILQ_NEXT(mp, mnt_list);
767 } else if (how & MNTSCAN_REVERSE) {
768 info.msi_node = TAILQ_LAST(&mountlist, mntlist);
769 while ((mp = info.msi_node) != NULL) {
771 if (how & MNTSCAN_NOBUSY) {
772 lwkt_reltoken(&mountlist_token);
773 count = callback(mp, data);
774 lwkt_gettoken_shared(&mountlist_token);
775 } else if (vfs_busy(mp, LK_NOWAIT) == 0) {
776 lwkt_reltoken(&mountlist_token);
777 count = callback(mp, data);
778 lwkt_gettoken_shared(&mountlist_token);
779 if (mp == info.msi_node)
788 if (mp == info.msi_node)
789 info.msi_node = TAILQ_PREV(mp, mntlist,
793 lwkt_reltoken(&mountlist_token);
795 lwkt_gettoken(&mountlist_token);
796 TAILQ_REMOVE(&mountscan_list, &info, msi_entry);
797 lwkt_reltoken(&mountlist_token);
803 * MOUNT RELATED VNODE FUNCTIONS
806 static struct kproc_desc vnlru_kp = {
811 SYSINIT(vnlru, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &vnlru_kp);
814 * Move a vnode from one mount queue to another.
817 insmntque(struct vnode *vp, struct mount *mp)
822 * Delete from old mount point vnode list, if on one.
824 if ((omp = vp->v_mount) != NULL) {
825 lwkt_gettoken(&omp->mnt_token);
826 KKASSERT(omp == vp->v_mount);
827 KASSERT(omp->mnt_nvnodelistsize > 0,
828 ("bad mount point vnode list size"));
830 omp->mnt_nvnodelistsize--;
831 lwkt_reltoken(&omp->mnt_token);
835 * Insert into list of vnodes for the new mount point, if available.
836 * The 'end' of the LRU list is the vnode prior to mp->mnt_syncer.
842 lwkt_gettoken(&mp->mnt_token);
844 if (mp->mnt_syncer) {
845 TAILQ_INSERT_BEFORE(mp->mnt_syncer, vp, v_nmntvnodes);
847 TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
849 mp->mnt_nvnodelistsize++;
850 lwkt_reltoken(&mp->mnt_token);
855 * Scan the vnodes under a mount point and issue appropriate callbacks.
857 * The fastfunc() callback is called with just the mountlist token held
858 * (no vnode lock). It may not block and the vnode may be undergoing
859 * modifications while the caller is processing it. The vnode will
860 * not be entirely destroyed, however, due to the fact that the mountlist
861 * token is held. A return value < 0 skips to the next vnode without calling
862 * the slowfunc(), a return value > 0 terminates the loop.
864 * WARNING! The fastfunc() should not indirect through vp->v_object, the vp
865 * data structure is unstable when called from fastfunc().
867 * The slowfunc() callback is called after the vnode has been successfully
868 * locked based on passed flags. The vnode is skipped if it gets rearranged
869 * or destroyed while blocking on the lock. A non-zero return value from
870 * the slow function terminates the loop. The slow function is allowed to
871 * arbitrarily block. The scanning code guarentees consistency of operation
872 * even if the slow function deletes or moves the node, or blocks and some
873 * other thread deletes or moves the node.
879 int (*fastfunc)(struct mount *mp, struct vnode *vp, void *data),
880 int (*slowfunc)(struct mount *mp, struct vnode *vp, void *data),
883 struct vmntvnodescan_info info;
886 int maxcount = mp->mnt_nvnodelistsize * 2;
890 lwkt_gettoken(&mp->mnt_token);
893 * If asked to do one pass stop after iterating available vnodes.
894 * Under heavy loads new vnodes can be added while we are scanning,
895 * so this isn't perfect. Create a slop factor of 2x.
897 if (flags & VMSC_ONEPASS)
898 stopcount = mp->mnt_nvnodelistsize;
900 info.vp = TAILQ_FIRST(&mp->mnt_nvnodelist);
901 TAILQ_INSERT_TAIL(&mp->mnt_vnodescan_list, &info, entry);
903 while ((vp = info.vp) != NULL) {
904 if (--maxcount == 0) {
905 kprintf("Warning: excessive fssync iteration\n");
906 maxcount = mp->mnt_nvnodelistsize * 2;
910 * Skip if visible but not ready, or special (e.g.
913 if (vp->v_type == VNON)
915 KKASSERT(vp->v_mount == mp);
918 * Quick test. A negative return continues the loop without
919 * calling the slow test. 0 continues onto the slow test.
920 * A positive number aborts the loop.
923 if ((r = fastfunc(mp, vp, data)) < 0) {
932 * Get a vxlock on the vnode, retry if it has moved or isn't
933 * in the mountlist where we expect it.
938 switch(flags & (VMSC_GETVP|VMSC_GETVX|VMSC_NOWAIT)) {
940 error = vget(vp, LK_EXCLUSIVE);
942 case VMSC_GETVP|VMSC_NOWAIT:
943 error = vget(vp, LK_EXCLUSIVE|LK_NOWAIT);
956 * Do not call the slow function if the vnode is
957 * invalid or if it was ripped out from under us
958 * while we (potentially) blocked.
960 if (info.vp == vp && vp->v_type != VNON)
961 r = slowfunc(mp, vp, data);
966 switch(flags & (VMSC_GETVP|VMSC_GETVX|VMSC_NOWAIT)) {
968 case VMSC_GETVP|VMSC_NOWAIT:
983 * Yield after some processing. Depending on the number
984 * of vnodes, we might wind up running for a long time.
985 * Because threads are not preemptable, time critical
986 * userland processes might starve. Give them a chance
989 if (++count == 10000) {
991 * We really want to yield a bit, so we simply
994 tsleep(mp, 0, "vnodescn", 1);
999 * If doing one pass this decrements to zero. If it starts
1000 * at zero it is effectively unlimited for the purposes of
1003 if (--stopcount == 0)
1007 * Iterate. If the vnode was ripped out from under us
1008 * info.vp will already point to the next vnode, otherwise
1009 * we have to obtain the next valid vnode ourselves.
1012 info.vp = TAILQ_NEXT(vp, v_nmntvnodes);
1015 TAILQ_REMOVE(&mp->mnt_vnodescan_list, &info, entry);
1016 lwkt_reltoken(&mp->mnt_token);
1021 * Remove any vnodes in the vnode table belonging to mount point mp.
1023 * If FORCECLOSE is not specified, there should not be any active ones,
1024 * return error if any are found (nb: this is a user error, not a
1025 * system error). If FORCECLOSE is specified, detach any active vnodes
1028 * If WRITECLOSE is set, only flush out regular file vnodes open for
1031 * SKIPSYSTEM causes any vnodes marked VSYSTEM to be skipped.
1033 * `rootrefs' specifies the base reference count for the root vnode
1034 * of this filesystem. The root vnode is considered busy if its
1035 * v_refcnt exceeds this value. On a successful return, vflush()
1036 * will call vrele() on the root vnode exactly rootrefs times.
1037 * If the SKIPSYSTEM or WRITECLOSE flags are specified, rootrefs must
1040 static int debug_busyprt = 0; /* print out busy vnodes */
1041 SYSCTL_INT(_vfs, OID_AUTO, debug_busyprt, CTLFLAG_RW, &debug_busyprt, 0, "");
1043 static int vflush_scan(struct mount *mp, struct vnode *vp, void *data);
1045 struct vflush_info {
1052 vflush(struct mount *mp, int rootrefs, int flags)
1054 struct thread *td = curthread; /* XXX */
1055 struct vnode *rootvp = NULL;
1057 struct vflush_info vflush_info;
1060 KASSERT((flags & (SKIPSYSTEM | WRITECLOSE)) == 0,
1061 ("vflush: bad args"));
1063 * Get the filesystem root vnode. We can vput() it
1064 * immediately, since with rootrefs > 0, it won't go away.
1066 if ((error = VFS_ROOT(mp, &rootvp)) != 0) {
1067 if ((flags & FORCECLOSE) == 0)
1070 /* continue anyway */
1076 vflush_info.busy = 0;
1077 vflush_info.flags = flags;
1078 vflush_info.td = td;
1079 vmntvnodescan(mp, VMSC_GETVX, NULL, vflush_scan, &vflush_info);
1081 if (rootrefs > 0 && (flags & FORCECLOSE) == 0) {
1083 * If just the root vnode is busy, and if its refcount
1084 * is equal to `rootrefs', then go ahead and kill it.
1086 KASSERT(vflush_info.busy > 0, ("vflush: not busy"));
1087 KASSERT(VREFCNT(rootvp) >= rootrefs, ("vflush: rootrefs"));
1088 if (vflush_info.busy == 1 && VREFCNT(rootvp) == rootrefs) {
1090 vgone_vxlocked(rootvp);
1092 vflush_info.busy = 0;
1095 if (vflush_info.busy)
1097 for (; rootrefs > 0; rootrefs--)
1103 * The scan callback is made with an VX locked vnode.
1106 vflush_scan(struct mount *mp, struct vnode *vp, void *data)
1108 struct vflush_info *info = data;
1110 int flags = info->flags;
1113 * Generally speaking try to deactivate on 0 refs (catch-all)
1115 atomic_set_int(&vp->v_refcnt, VREF_FINALIZE);
1118 * Skip over a vnodes marked VSYSTEM.
1120 if ((flags & SKIPSYSTEM) && (vp->v_flag & VSYSTEM)) {
1125 * Do not force-close VCHR or VBLK vnodes
1127 if (vp->v_type == VCHR || vp->v_type == VBLK)
1128 flags &= ~(WRITECLOSE|FORCECLOSE);
1131 * If WRITECLOSE is set, flush out unlinked but still open
1132 * files (even if open only for reading) and regular file
1133 * vnodes open for writing.
1135 if ((flags & WRITECLOSE) &&
1136 (vp->v_type == VNON ||
1137 (VOP_GETATTR(vp, &vattr) == 0 &&
1138 vattr.va_nlink > 0)) &&
1139 (vp->v_writecount == 0 || vp->v_type != VREG)) {
1144 * If we are the only holder (refcnt of 1) or the vnode is in
1145 * termination (refcnt < 0), we can vgone the vnode.
1147 if (VREFCNT(vp) <= 1) {
1153 * If FORCECLOSE is set, forcibly destroy the vnode and then move
1154 * it to a dummymount structure so vop_*() functions don't deref
1157 if (flags & FORCECLOSE) {
1160 if (vp->v_mount == NULL)
1161 insmntque(vp, &dummymount);
1165 if (vp->v_type == VCHR || vp->v_type == VBLK)
1166 kprintf("vflush: Warning, cannot destroy busy device vnode\n");
1167 if (debug_busyprt) {
1168 const char *filename;
1170 spin_lock(&vp->v_spin);
1171 filename = TAILQ_FIRST(&vp->v_namecache) ?
1172 TAILQ_FIRST(&vp->v_namecache)->nc_name : "?";
1173 spin_unlock(&vp->v_spin);
1174 kprintf("vflush: busy vnode (%p) %s\n", vp, filename);
1181 add_bio_ops(struct bio_ops *ops)
1183 TAILQ_INSERT_TAIL(&bio_ops_list, ops, entry);
1187 rem_bio_ops(struct bio_ops *ops)
1189 TAILQ_REMOVE(&bio_ops_list, ops, entry);
1193 * This calls the bio_ops io_sync function either for a mount point
1196 * WARNING: softdeps is weirdly coded and just isn't happy unless
1197 * io_sync is called with a NULL mount from the general syncing code.
1200 bio_ops_sync(struct mount *mp)
1202 struct bio_ops *ops;
1205 if ((ops = mp->mnt_bioops) != NULL)
1208 TAILQ_FOREACH(ops, &bio_ops_list, entry) {
1215 * Lookup a mount point by nch
1218 mount_get_by_nc(struct namecache *ncp)
1220 struct mount *mp = NULL;
1222 lwkt_gettoken_shared(&mountlist_token);
1223 TAILQ_FOREACH(mp, &mountlist, mnt_list) {
1224 if (ncp == mp->mnt_ncmountpt.ncp)
1227 lwkt_reltoken(&mountlist_token);