/* * 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 8.31 (Berkeley) 5/26/95 * $FreeBSD: src/sys/kern/vfs_subr.c,v 1.249.2.30 2003/04/04 20:35:57 tegge Exp $ */ /* * External virtual filesystem routines */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * The workitem queue. */ #define SYNCER_MAXDELAY 32 static int sysctl_kern_syncdelay(SYSCTL_HANDLER_ARGS); time_t syncdelay = 30; /* max time to delay syncing data */ SYSCTL_PROC(_kern, OID_AUTO, syncdelay, CTLTYPE_INT | CTLFLAG_RW, 0, 0, sysctl_kern_syncdelay, "I", "VFS data synchronization delay"); time_t filedelay = 30; /* time to delay syncing files */ SYSCTL_INT(_kern, OID_AUTO, filedelay, CTLFLAG_RW, &filedelay, 0, "File synchronization delay"); time_t dirdelay = 29; /* time to delay syncing directories */ SYSCTL_INT(_kern, OID_AUTO, dirdelay, CTLFLAG_RW, &dirdelay, 0, "Directory synchronization delay"); time_t metadelay = 28; /* time to delay syncing metadata */ SYSCTL_INT(_kern, OID_AUTO, metadelay, CTLFLAG_RW, &metadelay, 0, "VFS metadata synchronization delay"); time_t retrydelay = 1; /* retry delay after failure */ SYSCTL_INT(_kern, OID_AUTO, retrydelay, CTLFLAG_RW, &retrydelay, 0, "VFS retry synchronization delay"); static int rushjob; /* number of slots to run ASAP */ static int stat_rush_requests; /* number of times I/O speeded up */ SYSCTL_INT(_debug, OID_AUTO, rush_requests, CTLFLAG_RW, &stat_rush_requests, 0, ""); /* DF2832 witness counters (IN-GUEST ONLY) */ static int df2832_hits; static int df2832_starts; SYSCTL_INT(_debug, OID_AUTO, df2832_hits, CTLFLAG_RD, &df2832_hits, 0, ""); SYSCTL_INT(_debug, OID_AUTO, df2832_starts, CTLFLAG_RD, &df2832_starts, 0, ""); static int df2832_parked; /* threads currently parked in-window */ SYSCTL_INT(_debug, OID_AUTO, df2832_parked, CTLFLAG_RD, &df2832_parked, 0, ""); static struct mount *df2832_lastmp; /* last non-root mount w/ syncer */ static int sysctl_df2832_stop(SYSCTL_HANDLER_ARG); SYSCTL_PROC(_debug, OID_AUTO, df2832_stop, CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_df2832_stop, "I", "teardown last non-root syncer while a park is active"); LIST_HEAD(synclist, vnode); #define SC_FLAG_EXIT (0x1) /* request syncer exit */ #define SC_FLAG_DONE (0x2) /* syncer confirm exit */ struct syncer_ctx { struct mount *sc_mp; struct lwkt_token sc_token; struct thread *sc_thread; int sc_flags; struct synclist *syncer_workitem_pending; long syncer_mask; int syncer_delayno; int syncer_forced; int syncer_rushjob; /* sequence vnodes faster */ int syncer_trigger; /* trigger full sync */ long syncer_count; }; static void syncer_thread(void *); static int sysctl_kern_syncdelay(SYSCTL_HANDLER_ARGS) { int error; int v = syncdelay; error = sysctl_handle_int(oidp, &v, 0, req); if (error || !req->newptr) return (error); if (v < 1) v = 1; if (v > SYNCER_MAXDELAY) v = SYNCER_MAXDELAY; syncdelay = v; return(0); } /* * The workitem queue. * * It is useful to delay writes of file data and filesystem metadata * for tens of seconds so that quickly created and deleted files need * not waste disk bandwidth being created and removed. To realize this, * we append vnodes to a "workitem" queue. When running with a soft * updates implementation, most pending metadata dependencies should * not wait for more than a few seconds. Thus, mounted on block devices * are delayed only about a half the time that file data is delayed. * Similarly, directory updates are more critical, so are only delayed * about a third the time that file data is delayed. Thus, there are * SYNCER_MAXDELAY queues that are processed round-robin at a rate of * one each second (driven off the filesystem syncer process). The * syncer_delayno variable indicates the next queue that is to be processed. * Items that need to be processed soon are placed in this queue: * * syncer_workitem_pending[syncer_delayno] * * A delay of fifteen seconds is done by placing the request fifteen * entries later in the queue: * * syncer_workitem_pending[(syncer_delayno + 15) & syncer_mask] * */ /* * Return the number of vnodes on the syncer's timed list. This will * include the syncer vnode (mp->mnt_syncer) so if used, a minimum * value of 1 will be returned. */ long vn_syncer_count(struct mount *mp) { struct syncer_ctx *ctx; ctx = mp->mnt_syncer_ctx; if (ctx) return (ctx->syncer_count); return 0; } /* * Add an item to the syncer work queue. * * WARNING: Cannot get vp->v_token here if not already held, we must * depend on the syncer_token (which might already be held by * the caller) to protect v_synclist and VONWORKLST. * * WARNING: The syncer depends on this function not blocking if the caller * already holds the syncer token. */ void vn_syncer_add(struct vnode *vp, int delay) { struct syncer_ctx *ctx; int slot; ctx = vp->v_mount->mnt_syncer_ctx; lwkt_gettoken(&ctx->sc_token); if (vp->v_flag & VONWORKLST) { LIST_REMOVE(vp, v_synclist); --ctx->syncer_count; } if (delay <= 0) { slot = -delay & ctx->syncer_mask; } else { if (delay > SYNCER_MAXDELAY - 2) delay = SYNCER_MAXDELAY - 2; slot = (ctx->syncer_delayno + delay) & ctx->syncer_mask; } LIST_INSERT_HEAD(&ctx->syncer_workitem_pending[slot], vp, v_synclist); vsetflags(vp, VONWORKLST); ++ctx->syncer_count; lwkt_reltoken(&ctx->sc_token); } /* * Removes the vnode from the syncer list. Since we might block while * acquiring the syncer_token we have to [re]check conditions to determine * that it is ok to remove the vnode. * * Force removal if force != 0. This can only occur during a forced unmount. * * vp->v_token held on call */ void vn_syncer_remove(struct vnode *vp, int force) { struct syncer_ctx *ctx; ctx = vp->v_mount->mnt_syncer_ctx; lwkt_gettoken(&ctx->sc_token); if ((vp->v_flag & (VISDIRTY | VONWORKLST | VOBJDIRTY)) == VONWORKLST && RB_EMPTY(&vp->v_rbdirty_tree)) { vclrflags(vp, VONWORKLST); LIST_REMOVE(vp, v_synclist); --ctx->syncer_count; } else if (force && (vp->v_flag & VONWORKLST)) { vclrflags(vp, VONWORKLST); LIST_REMOVE(vp, v_synclist); --ctx->syncer_count; } lwkt_reltoken(&ctx->sc_token); } /* * vnode must be locked */ void vclrisdirty(struct vnode *vp) { vclrflags(vp, VISDIRTY); if (vp->v_flag & VONWORKLST) vn_syncer_remove(vp, 0); } void vclrobjdirty(struct vnode *vp) { vclrflags(vp, VOBJDIRTY); if (vp->v_flag & VONWORKLST) vn_syncer_remove(vp, 0); } /* * vnode must be stable */ void vsetisdirty(struct vnode *vp) { struct syncer_ctx *ctx; if ((vp->v_flag & VISDIRTY) == 0) { ctx = vp->v_mount->mnt_syncer_ctx; vsetflags(vp, VISDIRTY); lwkt_gettoken(&ctx->sc_token); if ((vp->v_flag & VONWORKLST) == 0) vn_syncer_add(vp, syncdelay); lwkt_reltoken(&ctx->sc_token); } } void vsetobjdirty(struct vnode *vp) { struct syncer_ctx *ctx; if ((vp->v_flag & VOBJDIRTY) == 0) { ctx = vp->v_mount->mnt_syncer_ctx; vsetflags(vp, VOBJDIRTY); lwkt_gettoken(&ctx->sc_token); if ((vp->v_flag & VONWORKLST) == 0) vn_syncer_add(vp, syncdelay); lwkt_reltoken(&ctx->sc_token); } } /* * Create per-filesystem syncer process */ void vn_syncer_thr_create(struct mount *mp) { struct syncer_ctx *ctx; static int syncalloc = 0; ctx = kmalloc(sizeof(struct syncer_ctx), M_TEMP, M_WAITOK | M_ZERO); ctx->sc_mp = mp; ctx->sc_flags = 0; ctx->syncer_workitem_pending = hashinit(SYNCER_MAXDELAY, M_DEVBUF, &ctx->syncer_mask); ctx->syncer_delayno = 0; lwkt_token_init(&ctx->sc_token, "syncer"); mp->mnt_syncer_ctx = ctx; if (rootvnode == NULL || mp != rootvnode->v_mount) df2832_lastmp = mp; kprintf("DF2832: CREATE ctx=%p mp=%p\n", ctx, mp); kthread_create(syncer_thread, ctx, &ctx->sc_thread, "syncer%d", ++syncalloc & 0x7FFFFFFF); } /* * Stop per-filesystem syncer process */ void vn_syncer_thr_stop(struct mount *mp) { struct syncer_ctx *ctx; ctx = mp->mnt_syncer_ctx; if (ctx == NULL) return; lwkt_gettoken(&ctx->sc_token); /* Signal the syncer process to exit */ ctx->sc_flags |= SC_FLAG_EXIT; wakeup(ctx); /* Wait till syncer process exits */ while ((ctx->sc_flags & SC_FLAG_DONE) == 0) { tsleep_interlock(&ctx->sc_flags, 0); lwkt_reltoken(&ctx->sc_token); tsleep(&ctx->sc_flags, PINTERLOCKED, "syncexit", hz); lwkt_gettoken(&ctx->sc_token); } mp->mnt_syncer_ctx = NULL; lwkt_reltoken(&ctx->sc_token); kprintf("DF2832: thr_stop FREE ctx=%p mp=%p\n", ctx, mp); hashdestroy(ctx->syncer_workitem_pending, M_DEVBUF, ctx->syncer_mask); kfree(ctx, M_TEMP); } /* * DF2832 witness teardown: invoke the REAL vn_syncer_thr_stop() on the * last non-root mount, but only once an unprivileged trigger caller is * observed parked inside the vulnerable window (df2832_parked > 0). */ static int sysctl_df2832_stop(SYSCTL_HANDLER_ARGS) { int error; int v = 0; struct mount *mp; int n; error = sysctl_handle_int(oidp, &v, 0, req); if (error || req->newptr == 0) return (error); if (v != 1) return (0); mp = df2832_lastmp; if (mp == NULL) { kprintf("DF2832: stop: no test mount\n"); return (0); } for (n = 0; n < 100 && df2832_parked == 0; ++n) tsleep(&df2832_parked, 0, "df2832s", 1); kprintf("DF2832: stop: parked=%d, tearing down syncer of mp=%p\n", df2832_parked, mp); vn_syncer_thr_stop(mp); /* the real teardown path */ df2832_lastmp = NULL; kprintf("DF2832: stop: teardown complete\n"); return (0); } struct thread *updatethread; /* * System filesystem synchronizer daemon. */ static void syncer_thread(void *_ctx) { struct syncer_ctx *ctx = _ctx; struct synclist *slp; struct vnode *vp; long starttime; int *sc_flagsp; int sc_flags; int vnodes_synced = 0; int delta; int dummy = 0; for (;;) { kproc_suspend_loop(); starttime = time_uptime; lwkt_gettoken(&ctx->sc_token); /* * Push files whose dirty time has expired. Be careful * of interrupt race on slp queue. * * Note that vsyncscan() and vn_syncer_one() can pull items * off the same list, so we shift vp's position in the * list immediately. */ slp = &ctx->syncer_workitem_pending[ctx->syncer_delayno]; /* * If syncer_trigger is set (from trigger_syncer(mp)), * Immediately do a full filesystem sync and set up the * following full filesystem sync to occur in 1 second. * * The normal syncer_trigger bit 0 is automatically reset. * If other bits are set, they remain set and cause the * syncer to keep running. */ if (ctx->syncer_trigger) { if (ctx->sc_mp && ctx->sc_mp->mnt_syncer) { vp = ctx->sc_mp->mnt_syncer; if (vp->v_flag & VONWORKLST) { vn_syncer_add(vp, retrydelay); if (vget(vp, LK_EXCLUSIVE) == 0) { atomic_clear_int(&ctx->syncer_trigger, 1); VOP_FSYNC(vp, MNT_LAZY, 0); vput(vp); vnodes_synced++; } } } } /* * FSYNC items in this bucket */ while ((vp = LIST_FIRST(slp)) != NULL) { vn_syncer_add(vp, retrydelay); if (ctx->syncer_forced) { if (vget(vp, LK_EXCLUSIVE) == 0) { VOP_FSYNC(vp, MNT_NOWAIT, 0); vput(vp); vnodes_synced++; } } else { if (vget(vp, LK_EXCLUSIVE | LK_NOWAIT) == 0) { VOP_FSYNC(vp, MNT_LAZY, 0); vput(vp); vnodes_synced++; } } } /* * Increment the slot upon completion. This is typically * one-second but may be faster if the syncer is triggered. */ ctx->syncer_delayno = (ctx->syncer_delayno + 1) & ctx->syncer_mask; sc_flags = ctx->sc_flags; /* Exit on unmount */ if (sc_flags & SC_FLAG_EXIT) break; lwkt_reltoken(&ctx->sc_token); /* * Do sync processing for each mount. */ if (ctx->sc_mp) bio_ops_sync(ctx->sc_mp); /* * The variable rushjob allows the kernel to speed up the * processing of the filesystem syncer process. A rushjob * value of N tells the filesystem syncer to process the next * N seconds worth of work on its queue ASAP. Currently rushjob * is used by the soft update code to speed up the filesystem * syncer process when the incore state is getting so far * ahead of the disk that the kernel memory pool is being * threatened with exhaustion. */ delta = rushjob - ctx->syncer_rushjob; if ((u_int)delta > syncdelay / 2) { ctx->syncer_rushjob = rushjob - syncdelay / 2; tsleep(&dummy, 0, "rush", 1); continue; } if (delta) { ++ctx->syncer_rushjob; tsleep(&dummy, 0, "rush", 1); continue; } /* * Normal syncer operation iterates once a second, unless * specifically triggered. */ if (time_uptime == starttime && ctx->syncer_trigger == 0) { tsleep_interlock(ctx, 0); if (time_uptime == starttime && ctx->syncer_trigger == 0 && (ctx->sc_flags & SC_FLAG_EXIT) == 0) { tsleep(ctx, PINTERLOCKED, "syncer", hz); } } } /* * Unmount/exit path for per-filesystem syncers; sc_token held */ ctx->sc_flags |= SC_FLAG_DONE; sc_flagsp = &ctx->sc_flags; lwkt_reltoken(&ctx->sc_token); wakeup(sc_flagsp); kthread_exit(); } /* * This allows a filesystem to pro-actively request that a dirty * vnode be fsync()d. This routine does not guarantee that one * will actually be fsynced. */ void vn_syncer_one(struct mount *mp) { struct syncer_ctx *ctx; struct synclist *slp; struct vnode *vp; int i; int n = syncdelay; ctx = mp->mnt_syncer_ctx; i = ctx->syncer_delayno & ctx->syncer_mask; cpu_ccfence(); if (lwkt_trytoken(&ctx->sc_token) == 0) return; /* * Look ahead on our syncer time array. */ do { slp = &ctx->syncer_workitem_pending[i]; vp = LIST_FIRST(slp); if (vp && vp->v_type == VNON) vp = LIST_NEXT(vp, v_synclist); if (vp) break; i = (i + 1) & ctx->syncer_mask; /* i will be wrong if we stop here but vp is NULL so ok */ } while(--n); /* * Process one vnode, skip the syncer vnode but also stop * if the syncer vnode is the only thing on this list. */ if (vp) { vn_syncer_add(vp, retrydelay); if (vget(vp, LK_EXCLUSIVE | LK_NOWAIT) == 0) { VOP_FSYNC(vp, MNT_LAZY, 0); vput(vp); } } lwkt_reltoken(&ctx->sc_token); } /* * Request that the syncer daemon for a specific mount speed up its work. * If mp is NULL the caller generally wants to speed up all syncers. */ void speedup_syncer(struct mount *mp) { /* * Don't bother protecting the test. unsleep_and_wakeup_thread() * will only do something real if the thread is in the right state. */ atomic_add_int(&rushjob, 1); ++stat_rush_requests; if (mp && mp->mnt_syncer_ctx) wakeup(mp->mnt_syncer_ctx); } /* * DF2832 witness: park up to ~500ms emulating preemption between the * mp->mnt_syncer_ctx load and the atomic RMW below. If the mount is torn * down while parked, mnt_syncer_ctx != local ctx, i.e. on the stock * kernel the RMW would operate on memory freed by vn_syncer_thr_stop(). * On HIT we print and REFRAIN from the RMW (pure evidence, no corruption). */ #define DF2832_PARK(ctx, fn) do { \ int _n; \ if ((ctx)->sc_mp == NULL || \ (rootvnode && (ctx)->sc_mp == rootvnode->v_mount)) { \ break; /* never park on the root fs */ \ } \ atomic_add_int(&df2832_parked, 1); \ for (_n = 0; _n < 150; ++_n) { \ if (mp->mnt_syncer_ctx != (ctx)) { \ atomic_add_int(&df2832_hits, 1); \ atomic_add_int(&df2832_parked, -1); \ kprintf("DF2832: HIT stale ctx=%p in " \ fn " after %d ms park (mp=%p)\n", \ (ctx), _n, mp); \ return; \ } \ tsleep(&df2832_hits, 0, "df2832w", 1); \ } \ atomic_add_int(&df2832_parked, -1); \ } while (0) /* * Force continuous full syncs until stopped. This may be used by * filesystems waiting on dirty data to be flushed to avoid syncer/tsleep * races. */ void trigger_syncer_start(struct mount *mp) { struct syncer_ctx *ctx; if (mp && (ctx = mp->mnt_syncer_ctx) != NULL) { atomic_add_int(&df2832_starts, 1); DF2832_PARK(ctx, "trigger_syncer_start"); if (atomic_fetchadd_int(&ctx->syncer_trigger, 2) <= 1) wakeup(ctx); } } void trigger_syncer_stop(struct mount *mp) { struct syncer_ctx *ctx; if (mp && (ctx = mp->mnt_syncer_ctx) != NULL) { atomic_add_int(&ctx->syncer_trigger, -2); } } /* * trigger a full sync (auto-reset) */ void trigger_syncer(struct mount *mp) { struct syncer_ctx *ctx; if (mp && (ctx = mp->mnt_syncer_ctx) != NULL) { if ((ctx->syncer_trigger & 1) == 0) { atomic_add_int(&df2832_starts, 1); DF2832_PARK(ctx, "trigger_syncer"); atomic_set_int(&ctx->syncer_trigger, 1); wakeup(ctx); } } } /* * Routine to create and manage a filesystem syncer vnode. */ static int sync_close(struct vop_close_args *); static int sync_fsync(struct vop_fsync_args *); static int sync_inactive(struct vop_inactive_args *); static int sync_reclaim (struct vop_reclaim_args *); static int sync_print(struct vop_print_args *); static struct vop_ops sync_vnode_vops = { .vop_default = vop_eopnotsupp, .vop_close = sync_close, .vop_fsync = sync_fsync, .vop_inactive = sync_inactive, .vop_reclaim = sync_reclaim, .vop_print = sync_print, }; static struct vop_ops *sync_vnode_vops_p = &sync_vnode_vops; VNODEOP_SET(sync_vnode_vops); /* * Create a new filesystem syncer vnode for the specified mount point. * This vnode is placed on the worklist and is responsible for sync'ing * the filesystem. * * NOTE: read-only mounts are also placed on the worklist. The filesystem * sync code is also responsible for cleaning up vnodes. */ int vfs_allocate_syncvnode(struct mount *mp) { struct vnode *vp; static long start, incr, next; int error; /* Allocate a new vnode */ error = getspecialvnode(VT_VFS, mp, &sync_vnode_vops_p, &vp, 0, 0); if (error) { mp->mnt_syncer = NULL; return (error); } vp->v_type = VNON; /* * Place the vnode onto the syncer worklist. We attempt to * scatter them about on the list so that they will go off * at evenly distributed times even if all the filesystems * are mounted at once. */ next += incr; if (next == 0 || next > SYNCER_MAXDELAY) { start /= 2; incr /= 2; if (start == 0) { start = SYNCER_MAXDELAY / 2; incr = SYNCER_MAXDELAY; } next = start; } /* * Only put the syncer vnode onto the syncer list if we have a * syncer thread. Some VFS's (aka NULLFS) don't need a syncer * thread. */ if (mp->mnt_syncer_ctx) vn_syncer_add(vp, syncdelay > 0 ? next % syncdelay : 0); /* * The mnt_syncer field inherits the vnode reference, which is * held until later decomissioning. */ mp->mnt_syncer = vp; vx_unlock(vp); return (0); } static int sync_close(struct vop_close_args *ap) { return (0); } /* * Do a lazy sync of the filesystem. * * sync_fsync { struct vnode *a_vp, int a_waitfor } */ static int sync_fsync(struct vop_fsync_args *ap) { struct vnode *syncvp = ap->a_vp; struct mount *mp = syncvp->v_mount; int asyncflag; /* * We only need to do something if this is a lazy evaluation. */ if ((ap->a_waitfor & MNT_LAZY) == 0) return (0); /* * Move ourselves to the back of the sync list. */ vn_syncer_add(syncvp, syncdelay); /* * Walk the list of vnodes pushing all that are dirty and * not already on the sync list, and freeing vnodes which have * no refs and whos VM objects are empty. vfs_msync() handles * the VM issues and must be called whether the mount is readonly * or not. */ if (vfs_busy(mp, LK_NOWAIT) != 0) return (0); if (mp->mnt_flag & MNT_RDONLY) { vfs_msync(mp, MNT_NOWAIT); } else { asyncflag = mp->mnt_flag & MNT_ASYNC; mp->mnt_flag &= ~MNT_ASYNC; /* ZZZ hack */ vfs_msync(mp, MNT_NOWAIT); VFS_SYNC(mp, MNT_NOWAIT | MNT_LAZY); if (asyncflag) mp->mnt_flag |= MNT_ASYNC; } vfs_unbusy(mp); return (0); } /* * The syncer vnode is no longer referenced. * * sync_inactive { struct vnode *a_vp, struct proc *a_p } */ static int sync_inactive(struct vop_inactive_args *ap) { vgone_vxlocked(ap->a_vp); return (0); } /* * The syncer vnode is no longer needed and is being decommissioned. * This can only occur when the last reference has been released on * mp->mnt_syncer, so mp->mnt_syncer had better be NULL. * * Modifications to the worklist must be protected with a critical * section. * * sync_reclaim { struct vnode *a_vp } */ static int sync_reclaim(struct vop_reclaim_args *ap) { struct vnode *vp = ap->a_vp; struct syncer_ctx *ctx; ctx = vp->v_mount->mnt_syncer_ctx; if (ctx) { lwkt_gettoken(&ctx->sc_token); KKASSERT(vp->v_mount->mnt_syncer != vp); if (vp->v_flag & VONWORKLST) { LIST_REMOVE(vp, v_synclist); vclrflags(vp, VONWORKLST); --ctx->syncer_count; } lwkt_reltoken(&ctx->sc_token); } else { KKASSERT((vp->v_flag & VONWORKLST) == 0); } return (0); } /* * This is very similar to vmntvnodescan() but it only scans the * vnodes on the syncer list. VFS's which support faster VFS_SYNC * operations use the VISDIRTY flag on the vnode to ensure that vnodes * with dirty inodes are added to the syncer in addition to vnodes * with dirty buffers, and can use this function instead of nmntvnodescan(). * * This scan does not issue VOP_FSYNC()s. The supplied callback is intended * to synchronize the file in the manner intended by the VFS using it. * * This is important when a system has millions of vnodes. */ int vsyncscan( struct mount *mp, int vmsc_flags, int (*slowfunc)(struct mount *mp, struct vnode *vp, void *data), void *data ) { struct syncer_ctx *ctx; struct synclist *slp; struct vnode *vp; int i; int count; int lkflags; if (vmsc_flags & VMSC_NOWAIT) lkflags = LK_NOWAIT; else lkflags = 0; /* * Syncer list context. This API requires a dedicated syncer thread. * (MNTK_THR_SYNC). */ KKASSERT(mp->mnt_kern_flag & MNTK_THR_SYNC); ctx = mp->mnt_syncer_ctx; lwkt_gettoken(&ctx->sc_token); /* * Setup for loop. Allow races against the syncer thread but * require that the syncer thread no be lazy if we were told * not to be lazy. */ i = ctx->syncer_delayno & ctx->syncer_mask; if ((vmsc_flags & VMSC_NOWAIT) == 0) ++ctx->syncer_forced; for (count = 0; count <= ctx->syncer_mask; ++count) { slp = &ctx->syncer_workitem_pending[i]; while ((vp = LIST_FIRST(slp)) != NULL) { KKASSERT(vp->v_mount == mp); if (vmsc_flags & VMSC_GETVP) { if (vget(vp, LK_EXCLUSIVE | lkflags) == 0) { slowfunc(mp, vp, data); vput(vp); } } else if (vmsc_flags & VMSC_GETVX) { vx_get(vp); slowfunc(mp, vp, data); vx_put(vp); } else { vhold(vp); slowfunc(mp, vp, data); vdrop(vp); } /* * vp could be invalid. However, if vp is still at * the head of the list it is clearly valid and we * can safely move it. */ if (LIST_FIRST(slp) == vp) vn_syncer_add(vp, -(i + syncdelay)); } i = (i + 1) & ctx->syncer_mask; } if ((vmsc_flags & VMSC_NOWAIT) == 0) --ctx->syncer_forced; lwkt_reltoken(&ctx->sc_token); return(0); } /* * Print out a syncer vnode. * * sync_print { struct vnode *a_vp } */ static int sync_print(struct vop_print_args *ap) { struct vnode *vp = ap->a_vp; kprintf("syncer vnode"); lockmgr_printinfo(&vp->v_lock); kprintf("\n"); return (0); }