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freebsd-skq/sys/kern/vfs_subr.c
dwhite 0bcdf7c033 This is a workaround for a complicated issue involving VFS cookies and devfs. 
The PR and patch have the details. The ultimate fix requires architectural
changes and clarifications to the VFS API, but this will prevent the system
from panicking when someone does "ls /dev" while running in a shell under the
linuxulator.

This issue affects HEAD and RELENG_6 only.

PR:		88249
Submitted by:	"Devon H. O'Dell" <dodell@ixsystems.com>
MFC after:	3 days
2005-11-09 22:03:50 +00:00

3905 lines
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/*-
* 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.
* 4. 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
*/
/*
* External virtual filesystem routines
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_ddb.h"
#include "opt_mac.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/conf.h>
#include <sys/dirent.h>
#include <sys/event.h>
#include <sys/eventhandler.h>
#include <sys/extattr.h>
#include <sys/file.h>
#include <sys/fcntl.h>
#include <sys/kdb.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/mac.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/reboot.h>
#include <sys/sleepqueue.h>
#include <sys/stat.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/vmmeter.h>
#include <sys/vnode.h>
#include <machine/stdarg.h>
#include <vm/vm.h>
#include <vm/vm_object.h>
#include <vm/vm_extern.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_page.h>
#include <vm/vm_kern.h>
#include <vm/uma.h>
static MALLOC_DEFINE(M_NETADDR, "subr_export_host", "Export host address structure");
static void delmntque(struct vnode *vp);
static void insmntque(struct vnode *vp, struct mount *mp);
static int flushbuflist(struct bufv *bufv, int flags, struct bufobj *bo,
int slpflag, int slptimeo);
static void syncer_shutdown(void *arg, int howto);
static int vtryrecycle(struct vnode *vp);
static void vbusy(struct vnode *vp);
static void vdropl(struct vnode *vp);
static void vinactive(struct vnode *, struct thread *);
static void v_incr_usecount(struct vnode *);
static void v_decr_usecount(struct vnode *);
static void v_decr_useonly(struct vnode *);
static void vfree(struct vnode *);
static void vnlru_free(int);
static void vdestroy(struct vnode *);
static void vgonel(struct vnode *);
static void vfs_knllock(void *arg);
static void vfs_knlunlock(void *arg);
static int vfs_knllocked(void *arg);
/*
* Enable Giant pushdown based on whether or not the vm is mpsafe in this
* build. Without mpsafevm the buffer cache can not run Giant free.
*/
#if defined(__alpha__) || defined(__amd64__) || defined(__i386__) || \
defined(__ia64__) || defined(__sparc64__)
int mpsafe_vfs = 1;
#else
int mpsafe_vfs;
#endif
TUNABLE_INT("debug.mpsafevfs", &mpsafe_vfs);
SYSCTL_INT(_debug, OID_AUTO, mpsafevfs, CTLFLAG_RD, &mpsafe_vfs, 0,
"MPSAFE VFS");
/*
* Number of vnodes in existence. Increased whenever getnewvnode()
* allocates a new vnode, never decreased.
*/
static unsigned long numvnodes;
SYSCTL_LONG(_vfs, OID_AUTO, numvnodes, CTLFLAG_RD, &numvnodes, 0, "");
/*
* Conversion tables for conversion from vnode types to inode formats
* and back.
*/
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,
};
/*
* List of vnodes that are ready for recycling.
*/
static TAILQ_HEAD(freelst, vnode) vnode_free_list;
/*
* Free vnode target. Free vnodes may simply be files which have been stat'd
* but not read. This is somewhat common, and a small cache of such files
* should be kept to avoid recreation costs.
*/
static u_long wantfreevnodes;
SYSCTL_LONG(_vfs, OID_AUTO, wantfreevnodes, CTLFLAG_RW, &wantfreevnodes, 0, "");
/* Number of vnodes in the free list. */
static u_long freevnodes;
SYSCTL_LONG(_vfs, OID_AUTO, freevnodes, CTLFLAG_RD, &freevnodes, 0, "");
/*
* Various variables used for debugging the new implementation of
* reassignbuf().
* XXX these are probably of (very) limited utility now.
*/
static int reassignbufcalls;
SYSCTL_INT(_vfs, OID_AUTO, reassignbufcalls, CTLFLAG_RW, &reassignbufcalls, 0, "");
/*
* Cache for the mount type id assigned to NFS. This is used for
* special checks in nfs/nfs_nqlease.c and vm/vnode_pager.c.
*/
int nfs_mount_type = -1;
/* To keep more than one thread at a time from running vfs_getnewfsid */
static struct mtx mntid_mtx;
/*
* Lock for any access to the following:
* vnode_free_list
* numvnodes
* freevnodes
*/
static struct mtx vnode_free_list_mtx;
/* Publicly exported FS */
struct nfs_public nfs_pub;
/* Zone for allocation of new vnodes - used exclusively by getnewvnode() */
static uma_zone_t vnode_zone;
static uma_zone_t vnodepoll_zone;
/* Set to 1 to print out reclaim of active vnodes */
int prtactive;
/*
* 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]
*
*/
static int syncer_delayno;
static long syncer_mask;
LIST_HEAD(synclist, bufobj);
static struct synclist *syncer_workitem_pending;
/*
* The sync_mtx protects:
* bo->bo_synclist
* sync_vnode_count
* syncer_delayno
* syncer_state
* syncer_workitem_pending
* syncer_worklist_len
* rushjob
*/
static struct mtx sync_mtx;
#define SYNCER_MAXDELAY 32
static int syncer_maxdelay = SYNCER_MAXDELAY; /* maximum delay time */
static int syncdelay = 30; /* max time to delay syncing data */
static int filedelay = 30; /* time to delay syncing files */
SYSCTL_INT(_kern, OID_AUTO, filedelay, CTLFLAG_RW, &filedelay, 0, "");
static int dirdelay = 29; /* time to delay syncing directories */
SYSCTL_INT(_kern, OID_AUTO, dirdelay, CTLFLAG_RW, &dirdelay, 0, "");
static int metadelay = 28; /* time to delay syncing metadata */
SYSCTL_INT(_kern, OID_AUTO, metadelay, CTLFLAG_RW, &metadelay, 0, "");
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, "");
/*
* When shutting down the syncer, run it at four times normal speed.
*/
#define SYNCER_SHUTDOWN_SPEEDUP 4
static int sync_vnode_count;
static int syncer_worklist_len;
static enum { SYNCER_RUNNING, SYNCER_SHUTTING_DOWN, SYNCER_FINAL_DELAY }
syncer_state;
/*
* Number of vnodes we want to exist at any one time. This is mostly used
* to size hash tables in vnode-related code. It is normally not used in
* getnewvnode(), as wantfreevnodes is normally nonzero.)
*
* XXX desiredvnodes is historical cruft and should not exist.
*/
int desiredvnodes;
SYSCTL_INT(_kern, KERN_MAXVNODES, maxvnodes, CTLFLAG_RW,
&desiredvnodes, 0, "Maximum number of vnodes");
SYSCTL_INT(_kern, OID_AUTO, minvnodes, CTLFLAG_RW,
&wantfreevnodes, 0, "Minimum number of vnodes (legacy)");
static int vnlru_nowhere;
SYSCTL_INT(_debug, OID_AUTO, vnlru_nowhere, CTLFLAG_RW,
&vnlru_nowhere, 0, "Number of times the vnlru process ran without success");
/* Hook for calling soft updates. */
int (*softdep_process_worklist_hook)(struct mount *);
/*
* Macros to control when a vnode is freed and recycled. All require
* the vnode interlock.
*/
#define VCANRECYCLE(vp) (((vp)->v_iflag & VI_FREE) && !(vp)->v_holdcnt)
#define VSHOULDFREE(vp) (!((vp)->v_iflag & VI_FREE) && !(vp)->v_holdcnt)
#define VSHOULDBUSY(vp) (((vp)->v_iflag & VI_FREE) && (vp)->v_holdcnt)
/*
* Initialize the vnode management data structures.
*/
#ifndef MAXVNODES_MAX
#define MAXVNODES_MAX 100000
#endif
static void
vntblinit(void *dummy __unused)
{
/*
* Desiredvnodes is a function of the physical memory size and
* the kernel's heap size. Specifically, desiredvnodes scales
* in proportion to the physical memory size until two fifths
* of the kernel's heap size is consumed by vnodes and vm
* objects.
*/
desiredvnodes = min(maxproc + cnt.v_page_count / 4, 2 * vm_kmem_size /
(5 * (sizeof(struct vm_object) + sizeof(struct vnode))));
if (desiredvnodes > MAXVNODES_MAX) {
if (bootverbose)
printf("Reducing kern.maxvnodes %d -> %d\n",
desiredvnodes, MAXVNODES_MAX);
desiredvnodes = MAXVNODES_MAX;
}
wantfreevnodes = desiredvnodes / 4;
mtx_init(&mntid_mtx, "mntid", NULL, MTX_DEF);
TAILQ_INIT(&vnode_free_list);
mtx_init(&vnode_free_list_mtx, "vnode_free_list", NULL, MTX_DEF);
vnode_zone = uma_zcreate("VNODE", sizeof (struct vnode), NULL, NULL,
NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
vnodepoll_zone = uma_zcreate("VNODEPOLL", sizeof (struct vpollinfo),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
/*
* Initialize the filesystem syncer.
*/
syncer_workitem_pending = hashinit(syncer_maxdelay, M_VNODE,
&syncer_mask);
syncer_maxdelay = syncer_mask + 1;
mtx_init(&sync_mtx, "Syncer mtx", NULL, MTX_DEF);
}
SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_FIRST, vntblinit, NULL)
/*
* Mark a mount point as busy. Used to synchronize access and to delay
* unmounting. Interlock is not released on failure.
*/
int
vfs_busy(mp, flags, interlkp, td)
struct mount *mp;
int flags;
struct mtx *interlkp;
struct thread *td;
{
int lkflags;
MNT_ILOCK(mp);
if (mp->mnt_kern_flag & MNTK_UNMOUNT) {
if (flags & LK_NOWAIT) {
MNT_IUNLOCK(mp);
return (ENOENT);
}
if (interlkp)
mtx_unlock(interlkp);
mp->mnt_kern_flag |= MNTK_MWAIT;
/*
* Since all busy locks are shared except the exclusive
* lock granted when unmounting, the only place that a
* wakeup needs to be done is at the release of the
* exclusive lock at the end of dounmount.
*/
msleep(mp, MNT_MTX(mp), PVFS|PDROP, "vfs_busy", 0);
if (interlkp)
mtx_lock(interlkp);
return (ENOENT);
}
if (interlkp)
mtx_unlock(interlkp);
lkflags = LK_SHARED | LK_INTERLOCK;
if (lockmgr(&mp->mnt_lock, lkflags, MNT_MTX(mp), td))
panic("vfs_busy: unexpected lock failure");
return (0);
}
/*
* Free a busy filesystem.
*/
void
vfs_unbusy(mp, td)
struct mount *mp;
struct thread *td;
{
lockmgr(&mp->mnt_lock, LK_RELEASE, NULL, td);
}
/*
* Lookup a mount point by filesystem identifier.
*/
struct mount *
vfs_getvfs(fsid)
fsid_t *fsid;
{
struct mount *mp;
mtx_lock(&mountlist_mtx);
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]) {
mtx_unlock(&mountlist_mtx);
return (mp);
}
}
mtx_unlock(&mountlist_mtx);
return ((struct mount *) 0);
}
/*
* Check if a user can access priveledged mount options.
*/
int
vfs_suser(struct mount *mp, struct thread *td)
{
int error;
if ((mp->mnt_flag & MNT_USER) == 0 ||
mp->mnt_cred->cr_uid != td->td_ucred->cr_uid) {
if ((error = suser(td)) != 0)
return (error);
}
return (0);
}
/*
* Get a new unique fsid. Try to make its val[0] unique, since this value
* will be used to create fake device numbers for stat(). Also try (but
* not so hard) make its val[0] unique mod 2^16, since some emulators only
* support 16-bit device numbers. We end up with unique val[0]'s for the
* first 2^16 calls and unique val[0]'s mod 2^16 for the first 2^8 calls.
*
* Keep in mind that several mounts may be running in parallel. Starting
* the search one past where the previous search terminated is both a
* micro-optimization and a defense against returning the same fsid to
* different mounts.
*/
void
vfs_getnewfsid(mp)
struct mount *mp;
{
static u_int16_t mntid_base;
fsid_t tfsid;
int mtype;
mtx_lock(&mntid_mtx);
mtype = mp->mnt_vfc->vfc_typenum;
tfsid.val[1] = mtype;
mtype = (mtype & 0xFF) << 24;
for (;;) {
tfsid.val[0] = makedev(255,
mtype | ((mntid_base & 0xFF00) << 8) | (mntid_base & 0xFF));
mntid_base++;
if (vfs_getvfs(&tfsid) == NULL)
break;
}
mp->mnt_stat.f_fsid.val[0] = tfsid.val[0];
mp->mnt_stat.f_fsid.val[1] = tfsid.val[1];
mtx_unlock(&mntid_mtx);
}
/*
* Knob to control the precision of file timestamps:
*
* 0 = seconds only; nanoseconds zeroed.
* 1 = seconds and nanoseconds, accurate within 1/HZ.
* 2 = seconds and nanoseconds, truncated to microseconds.
* >=3 = seconds and nanoseconds, maximum precision.
*/
enum { TSP_SEC, TSP_HZ, TSP_USEC, TSP_NSEC };
static int timestamp_precision = TSP_SEC;
SYSCTL_INT(_vfs, OID_AUTO, timestamp_precision, CTLFLAG_RW,
&timestamp_precision, 0, "");
/*
* Get a current timestamp.
*/
void
vfs_timestamp(tsp)
struct timespec *tsp;
{
struct timeval tv;
switch (timestamp_precision) {
case TSP_SEC:
tsp->tv_sec = time_second;
tsp->tv_nsec = 0;
break;
case TSP_HZ:
getnanotime(tsp);
break;
case TSP_USEC:
microtime(&tv);
TIMEVAL_TO_TIMESPEC(&tv, tsp);
break;
case TSP_NSEC:
default:
nanotime(tsp);
break;
}
}
/*
* Set vnode attributes to VNOVAL
*/
void
vattr_null(vap)
struct vattr *vap;
{
vap->va_type = VNON;
vap->va_size = VNOVAL;
vap->va_bytes = VNOVAL;
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_blocksize = VNOVAL;
vap->va_rdev = 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_birthtime.tv_sec = VNOVAL;
vap->va_birthtime.tv_nsec = VNOVAL;
vap->va_flags = VNOVAL;
vap->va_gen = VNOVAL;
vap->va_vaflags = 0;
}
/*
* This routine is called when we have too many vnodes. It attempts
* to free <count> vnodes and will potentially free vnodes that still
* have VM backing store (VM backing store is typically the cause
* of a vnode blowout so we want to do this). Therefore, this operation
* is not considered cheap.
*
* A number of conditions may prevent a vnode from being reclaimed.
* the buffer cache may have references on the vnode, a directory
* vnode may still have references due to the namei cache representing
* underlying files, or the vnode may be in active use. It is not
* desireable to reuse such vnodes. These conditions may cause the
* number of vnodes to reach some minimum value regardless of what
* you set kern.maxvnodes to. Do not set kern.maxvnodes too low.
*/
static int
vlrureclaim(struct mount *mp)
{
struct thread *td;
struct vnode *vp;
int done;
int trigger;
int usevnodes;
int count;
/*
* Calculate the trigger point, don't allow user
* screwups to blow us up. This prevents us from
* recycling vnodes with lots of resident pages. We
* aren't trying to free memory, we are trying to
* free vnodes.
*/
usevnodes = desiredvnodes;
if (usevnodes <= 0)
usevnodes = 1;
trigger = cnt.v_page_count * 2 / usevnodes;
done = 0;
td = curthread;
vn_start_write(NULL, &mp, V_WAIT);
MNT_ILOCK(mp);
count = mp->mnt_nvnodelistsize / 10 + 1;
while (count && (vp = TAILQ_FIRST(&mp->mnt_nvnodelist)) != NULL) {
TAILQ_REMOVE(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
--count;
if (!VI_TRYLOCK(vp))
goto next_iter;
/*
* If it's been deconstructed already, it's still
* referenced, or it exceeds the trigger, skip it.
*/
if (vp->v_usecount || !LIST_EMPTY(&(vp)->v_cache_src) ||
(vp->v_iflag & VI_DOOMED) != 0 || (vp->v_object != NULL &&
vp->v_object->resident_page_count > trigger)) {
VI_UNLOCK(vp);
goto next_iter;
}
MNT_IUNLOCK(mp);
vholdl(vp);
if (VOP_LOCK(vp, LK_INTERLOCK|LK_EXCLUSIVE|LK_NOWAIT, td)) {
vdrop(vp);
goto next_iter_mntunlocked;
}
VI_LOCK(vp);
/*
* v_usecount may have been bumped after VOP_LOCK() dropped
* the vnode interlock and before it was locked again.
*
* It is not necessary to recheck VI_DOOMED because it can
* only be set by another thread that holds both the vnode
* lock and vnode interlock. If another thread has the
* vnode lock before we get to VOP_LOCK() and obtains the
* vnode interlock after VOP_LOCK() drops the vnode
* interlock, the other thread will be unable to drop the
* vnode lock before our VOP_LOCK() call fails.
*/
if (vp->v_usecount || !LIST_EMPTY(&(vp)->v_cache_src) ||
(vp->v_object != NULL &&
vp->v_object->resident_page_count > trigger)) {
VOP_UNLOCK(vp, LK_INTERLOCK, td);
goto next_iter_mntunlocked;
}
KASSERT((vp->v_iflag & VI_DOOMED) == 0,
("VI_DOOMED unexpectedly detected in vlrureclaim()"));
vgonel(vp);
VOP_UNLOCK(vp, 0, td);
vdropl(vp);
done++;
next_iter_mntunlocked:
if ((count % 256) != 0)
goto relock_mnt;
goto yield;
next_iter:
if ((count % 256) != 0)
continue;
MNT_IUNLOCK(mp);
yield:
uio_yield();
relock_mnt:
MNT_ILOCK(mp);
}
MNT_IUNLOCK(mp);
vn_finished_write(mp);
return done;
}
/*
* Attempt to keep the free list at wantfreevnodes length.
*/
static void
vnlru_free(int count)
{
struct vnode *vp;
mtx_assert(&vnode_free_list_mtx, MA_OWNED);
for (; count > 0; count--) {
vp = TAILQ_FIRST(&vnode_free_list);
/*
* The list can be modified while the free_list_mtx
* has been dropped and vp could be NULL here.
*/
if (!vp)
break;
VNASSERT(vp->v_op != NULL, vp,
("vnlru_free: vnode already reclaimed."));
TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
/*
* Don't recycle if we can't get the interlock.
*/
if (!VI_TRYLOCK(vp)) {
TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
continue;
}
VNASSERT(VCANRECYCLE(vp), vp,
("vp inconsistent on freelist"));
freevnodes--;
vp->v_iflag &= ~VI_FREE;
vholdl(vp);
mtx_unlock(&vnode_free_list_mtx);
VI_UNLOCK(vp);
vtryrecycle(vp);
/*
* If the recycled succeeded this vdrop will actually free
* the vnode. If not it will simply place it back on
* the free list.
*/
vdrop(vp);
mtx_lock(&vnode_free_list_mtx);
}
}
/*
* Attempt to recycle vnodes in a context that is always safe to block.
* Calling vlrurecycle() from the bowels of filesystem code has some
* interesting deadlock problems.
*/
static struct proc *vnlruproc;
static int vnlruproc_sig;
static void
vnlru_proc(void)
{
struct mount *mp, *nmp;
int done;
struct proc *p = vnlruproc;
struct thread *td = FIRST_THREAD_IN_PROC(p);
mtx_lock(&Giant);
EVENTHANDLER_REGISTER(shutdown_pre_sync, kproc_shutdown, p,
SHUTDOWN_PRI_FIRST);
for (;;) {
kthread_suspend_check(p);
mtx_lock(&vnode_free_list_mtx);
if (freevnodes > wantfreevnodes)
vnlru_free(freevnodes - wantfreevnodes);
if (numvnodes <= desiredvnodes * 9 / 10) {
vnlruproc_sig = 0;
wakeup(&vnlruproc_sig);
msleep(vnlruproc, &vnode_free_list_mtx,
PVFS|PDROP, "vlruwt", hz);
continue;
}
mtx_unlock(&vnode_free_list_mtx);
done = 0;
mtx_lock(&mountlist_mtx);
for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
int vfsunlocked;
if (vfs_busy(mp, LK_NOWAIT, &mountlist_mtx, td)) {
nmp = TAILQ_NEXT(mp, mnt_list);
continue;
}
if (!VFS_NEEDSGIANT(mp)) {
mtx_unlock(&Giant);
vfsunlocked = 1;
} else
vfsunlocked = 0;
done += vlrureclaim(mp);
if (vfsunlocked)
mtx_lock(&Giant);
mtx_lock(&mountlist_mtx);
nmp = TAILQ_NEXT(mp, mnt_list);
vfs_unbusy(mp, td);
}
mtx_unlock(&mountlist_mtx);
if (done == 0) {
#if 0
/* These messages are temporary debugging aids */
if (vnlru_nowhere < 5)
printf("vnlru process getting nowhere..\n");
else if (vnlru_nowhere == 5)
printf("vnlru process messages stopped.\n");
#endif
vnlru_nowhere++;
tsleep(vnlruproc, PPAUSE, "vlrup", hz * 3);
} else
uio_yield();
}
}
static struct kproc_desc vnlru_kp = {
"vnlru",
vnlru_proc,
&vnlruproc
};
SYSINIT(vnlru, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &vnlru_kp)
/*
* Routines having to do with the management of the vnode table.
*/
static void
vdestroy(struct vnode *vp)
{
struct bufobj *bo;
CTR1(KTR_VFS, "vdestroy vp %p", vp);
mtx_lock(&vnode_free_list_mtx);
numvnodes--;
mtx_unlock(&vnode_free_list_mtx);
bo = &vp->v_bufobj;
VNASSERT((vp->v_iflag & VI_FREE) == 0, vp,
("cleaned vnode still on the free list."));
VNASSERT(vp->v_data == NULL, vp, ("cleaned vnode isn't"));
VNASSERT(vp->v_holdcnt == 0, vp, ("Non-zero hold count"));
VNASSERT(vp->v_usecount == 0, vp, ("Non-zero use count"));
VNASSERT(vp->v_writecount == 0, vp, ("Non-zero write count"));
VNASSERT(bo->bo_numoutput == 0, vp, ("Clean vnode has pending I/O's"));
VNASSERT(bo->bo_clean.bv_cnt == 0, vp, ("cleanbufcnt not 0"));
VNASSERT(bo->bo_clean.bv_root == NULL, vp, ("cleanblkroot not NULL"));
VNASSERT(bo->bo_dirty.bv_cnt == 0, vp, ("dirtybufcnt not 0"));
VNASSERT(bo->bo_dirty.bv_root == NULL, vp, ("dirtyblkroot not NULL"));
VNASSERT(TAILQ_EMPTY(&vp->v_cache_dst), vp, ("vp has namecache dst"));
VNASSERT(LIST_EMPTY(&vp->v_cache_src), vp, ("vp has namecache src"));
VI_UNLOCK(vp);
#ifdef MAC
mac_destroy_vnode(vp);
#endif
if (vp->v_pollinfo != NULL) {
knlist_destroy(&vp->v_pollinfo->vpi_selinfo.si_note);
mtx_destroy(&vp->v_pollinfo->vpi_lock);
uma_zfree(vnodepoll_zone, vp->v_pollinfo);
}
#ifdef INVARIANTS
/* XXX Elsewhere we can detect an already freed vnode via NULL v_op. */
vp->v_op = NULL;
#endif
lockdestroy(vp->v_vnlock);
mtx_destroy(&vp->v_interlock);
uma_zfree(vnode_zone, vp);
}
/*
* Try to recycle a freed vnode. We abort if anyone picks up a reference
* before we actually vgone(). This function must be called with the vnode
* held to prevent the vnode from being returned to the free list midway
* through vgone().
*/
static int
vtryrecycle(struct vnode *vp)
{
struct thread *td = curthread;
struct mount *vnmp;
CTR1(KTR_VFS, "vtryrecycle: trying vp %p", vp);
VNASSERT(vp->v_holdcnt, vp,
("vtryrecycle: Recycling vp %p without a reference.", vp));
/*
* This vnode may found and locked via some other list, if so we
* can't recycle it yet.
*/
if (VOP_LOCK(vp, LK_EXCLUSIVE | LK_NOWAIT, td) != 0)
return (EWOULDBLOCK);
/*
* Don't recycle if its filesystem is being suspended.
*/
if (vn_start_write(vp, &vnmp, V_NOWAIT) != 0) {
VOP_UNLOCK(vp, 0, td);
return (EBUSY);
}
/*
* If we got this far, we need to acquire the interlock and see if
* anyone picked up this vnode from another list. If not, we will
* mark it with DOOMED via vgonel() so that anyone who does find it
* will skip over it.
*/
VI_LOCK(vp);
if (vp->v_usecount) {
VOP_UNLOCK(vp, LK_INTERLOCK, td);
vn_finished_write(vnmp);
return (EBUSY);
}
if ((vp->v_iflag & VI_DOOMED) == 0)
vgonel(vp);
VOP_UNLOCK(vp, LK_INTERLOCK, td);
vn_finished_write(vnmp);
CTR1(KTR_VFS, "vtryrecycle: recycled vp %p", vp);
return (0);
}
/*
* Return the next vnode from the free list.
*/
int
getnewvnode(tag, mp, vops, vpp)
const char *tag;
struct mount *mp;
struct vop_vector *vops;
struct vnode **vpp;
{
struct vnode *vp = NULL;
struct bufobj *bo;
mtx_lock(&vnode_free_list_mtx);
/*
* Lend our context to reclaim vnodes if they've exceeded the max.
*/
if (freevnodes > wantfreevnodes)
vnlru_free(1);
/*
* Wait for available vnodes.
*/
if (numvnodes > desiredvnodes) {
if (vnlruproc_sig == 0) {
vnlruproc_sig = 1; /* avoid unnecessary wakeups */
wakeup(vnlruproc);
}
msleep(&vnlruproc_sig, &vnode_free_list_mtx, PVFS,
"vlruwk", hz);
#if 0 /* XXX Not all VFS_VGET/ffs_vget callers check returns. */
if (numvnodes > desiredvnodes) {
mtx_unlock(&vnode_free_list_mtx);
return (ENFILE);
}
#endif
}
numvnodes++;
mtx_unlock(&vnode_free_list_mtx);
vp = (struct vnode *) uma_zalloc(vnode_zone, M_WAITOK|M_ZERO);
/*
* Setup locks.
*/
vp->v_vnlock = &vp->v_lock;
mtx_init(&vp->v_interlock, "vnode interlock", NULL, MTX_DEF);
/*
* By default, don't allow shared locks unless filesystems
* opt-in.
*/
lockinit(vp->v_vnlock, PVFS, tag, VLKTIMEOUT, LK_NOSHARE);
/*
* Initialize bufobj.
*/
bo = &vp->v_bufobj;
bo->__bo_vnode = vp;
bo->bo_mtx = &vp->v_interlock;
bo->bo_ops = &buf_ops_bio;
bo->bo_private = vp;
TAILQ_INIT(&bo->bo_clean.bv_hd);
TAILQ_INIT(&bo->bo_dirty.bv_hd);
/*
* Initialize namecache.
*/
LIST_INIT(&vp->v_cache_src);
TAILQ_INIT(&vp->v_cache_dst);
/*
* Finalize various vnode identity bits.
*/
vp->v_type = VNON;
vp->v_tag = tag;
vp->v_op = vops;
v_incr_usecount(vp);
vp->v_data = 0;
#ifdef MAC
mac_init_vnode(vp);
if (mp != NULL && (mp->mnt_flag & MNT_MULTILABEL) == 0)
mac_associate_vnode_singlelabel(mp, vp);
else if (mp == NULL)
printf("NULL mp in getnewvnode()\n");
#endif
delmntque(vp);
if (mp != NULL) {
insmntque(vp, mp);
bo->bo_bsize = mp->mnt_stat.f_iosize;
if ((mp->mnt_kern_flag & MNTK_NOKNOTE) != 0)
vp->v_vflag |= VV_NOKNOTE;
}
CTR2(KTR_VFS, "getnewvnode: mp %p vp %p", mp, vp);
*vpp = vp;
return (0);
}
/*
* Delete from old mount point vnode list, if on one.
*/
static void
delmntque(struct vnode *vp)
{
struct mount *mp;
if (vp->v_mount == NULL)
return;
mp = vp->v_mount;
MNT_ILOCK(mp);
vp->v_mount = NULL;
VNASSERT(mp->mnt_nvnodelistsize > 0, vp,
("bad mount point vnode list size"));
TAILQ_REMOVE(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
mp->mnt_nvnodelistsize--;
MNT_IUNLOCK(mp);
}
/*
* Insert into list of vnodes for the new mount point, if available.
*/
static void
insmntque(struct vnode *vp, struct mount *mp)
{
vp->v_mount = mp;
VNASSERT(mp != NULL, vp, ("Don't call insmntque(foo, NULL)"));
MNT_ILOCK(vp->v_mount);
TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
mp->mnt_nvnodelistsize++;
MNT_IUNLOCK(vp->v_mount);
}
/*
* Flush out and invalidate all buffers associated with a bufobj
* Called with the underlying object locked.
*/
int
bufobj_invalbuf(struct bufobj *bo, int flags, struct thread *td, int slpflag, int slptimeo)
{
int error;
BO_LOCK(bo);
if (flags & V_SAVE) {
error = bufobj_wwait(bo, slpflag, slptimeo);
if (error) {
BO_UNLOCK(bo);
return (error);
}
if (bo->bo_dirty.bv_cnt > 0) {
BO_UNLOCK(bo);
if ((error = BO_SYNC(bo, MNT_WAIT, td)) != 0)
return (error);
/*
* XXX We could save a lock/unlock if this was only
* enabled under INVARIANTS
*/
BO_LOCK(bo);
if (bo->bo_numoutput > 0 || bo->bo_dirty.bv_cnt > 0)
panic("vinvalbuf: dirty bufs");
}
}
/*
* If you alter this loop please notice that interlock is dropped and
* reacquired in flushbuflist. Special care is needed to ensure that
* no race conditions occur from this.
*/
do {
error = flushbuflist(&bo->bo_clean,
flags, bo, slpflag, slptimeo);
if (error == 0)
error = flushbuflist(&bo->bo_dirty,
flags, bo, slpflag, slptimeo);
if (error != 0 && error != EAGAIN) {
BO_UNLOCK(bo);
return (error);
}
} while (error != 0);
/*
* Wait for I/O to complete. XXX needs cleaning up. The vnode can
* have write I/O in-progress but if there is a VM object then the
* VM object can also have read-I/O in-progress.
*/
do {
bufobj_wwait(bo, 0, 0);
BO_UNLOCK(bo);
if (bo->bo_object != NULL) {
VM_OBJECT_LOCK(bo->bo_object);
vm_object_pip_wait(bo->bo_object, "bovlbx");
VM_OBJECT_UNLOCK(bo->bo_object);
}
BO_LOCK(bo);
} while (bo->bo_numoutput > 0);
BO_UNLOCK(bo);
/*
* Destroy the copy in the VM cache, too.
*/
if (bo->bo_object != NULL) {
VM_OBJECT_LOCK(bo->bo_object);
vm_object_page_remove(bo->bo_object, 0, 0,
(flags & V_SAVE) ? TRUE : FALSE);
VM_OBJECT_UNLOCK(bo->bo_object);
}
#ifdef INVARIANTS
BO_LOCK(bo);
if ((flags & (V_ALT | V_NORMAL)) == 0 &&
(bo->bo_dirty.bv_cnt > 0 || bo->bo_clean.bv_cnt > 0))
panic("vinvalbuf: flush failed");
BO_UNLOCK(bo);
#endif
return (0);
}
/*
* Flush out and invalidate all buffers associated with a vnode.
* Called with the underlying object locked.
*/
int
vinvalbuf(struct vnode *vp, int flags, struct thread *td, int slpflag, int slptimeo)
{
CTR2(KTR_VFS, "vinvalbuf vp %p flags %d", vp, flags);
ASSERT_VOP_LOCKED(vp, "vinvalbuf");
return (bufobj_invalbuf(&vp->v_bufobj, flags, td, slpflag, slptimeo));
}
/*
* Flush out buffers on the specified list.
*
*/
static int
flushbuflist(bufv, flags, bo, slpflag, slptimeo)
struct bufv *bufv;
int flags;
struct bufobj *bo;
int slpflag, slptimeo;
{
struct buf *bp, *nbp;
int retval, error;
daddr_t lblkno;
b_xflags_t xflags;
ASSERT_BO_LOCKED(bo);
retval = 0;
TAILQ_FOREACH_SAFE(bp, &bufv->bv_hd, b_bobufs, nbp) {
if (((flags & V_NORMAL) && (bp->b_xflags & BX_ALTDATA)) ||
((flags & V_ALT) && (bp->b_xflags & BX_ALTDATA) == 0)) {
continue;
}
lblkno = 0;
xflags = 0;
if (nbp != NULL) {
lblkno = nbp->b_lblkno;
xflags = nbp->b_xflags &
(BX_BKGRDMARKER | BX_VNDIRTY | BX_VNCLEAN);
}
retval = EAGAIN;
error = BUF_TIMELOCK(bp,
LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK, BO_MTX(bo),
"flushbuf", slpflag, slptimeo);
if (error) {
BO_LOCK(bo);
return (error != ENOLCK ? error : EAGAIN);
}
KASSERT(bp->b_bufobj == bo,
("bp %p wrong b_bufobj %p should be %p",
bp, bp->b_bufobj, bo));
if (bp->b_bufobj != bo) { /* XXX: necessary ? */
BUF_UNLOCK(bp);
BO_LOCK(bo);
return (EAGAIN);
}
/*
* XXX Since there are no node locks for NFS, I
* believe there is a slight chance that a delayed
* write will occur while sleeping just above, so
* check for it.
*/
if (((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) &&
(flags & V_SAVE)) {
bremfree(bp);
bp->b_flags |= B_ASYNC;
bwrite(bp);
BO_LOCK(bo);
return (EAGAIN); /* XXX: why not loop ? */
}
bremfree(bp);
bp->b_flags |= (B_INVAL | B_NOCACHE | B_RELBUF);
bp->b_flags &= ~B_ASYNC;
brelse(bp);
BO_LOCK(bo);
if (nbp != NULL &&
(nbp->b_bufobj != bo ||
nbp->b_lblkno != lblkno ||
(nbp->b_xflags &
(BX_BKGRDMARKER | BX_VNDIRTY | BX_VNCLEAN)) != xflags))
break; /* nbp invalid */
}
return (retval);
}
/*
* Truncate a file's buffer and pages to a specified length. This
* is in lieu of the old vinvalbuf mechanism, which performed unneeded
* sync activity.
*/
int
vtruncbuf(struct vnode *vp, struct ucred *cred, struct thread *td, off_t length, int blksize)
{
struct buf *bp, *nbp;
int anyfreed;
int trunclbn;
struct bufobj *bo;
CTR2(KTR_VFS, "vtruncbuf vp %p length %jd", vp, length);
/*
* Round up to the *next* lbn.
*/
trunclbn = (length + blksize - 1) / blksize;
ASSERT_VOP_LOCKED(vp, "vtruncbuf");
restart:
VI_LOCK(vp);
bo = &vp->v_bufobj;
anyfreed = 1;
for (;anyfreed;) {
anyfreed = 0;
TAILQ_FOREACH_SAFE(bp, &bo->bo_clean.bv_hd, b_bobufs, nbp) {
if (bp->b_lblkno < trunclbn)
continue;
if (BUF_LOCK(bp,
LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
VI_MTX(vp)) == ENOLCK)
goto restart;
bremfree(bp);
bp->b_flags |= (B_INVAL | B_RELBUF);
bp->b_flags &= ~B_ASYNC;
brelse(bp);
anyfreed = 1;
if (nbp != NULL &&
(((nbp->b_xflags & BX_VNCLEAN) == 0) ||
(nbp->b_vp != vp) ||
(nbp->b_flags & B_DELWRI))) {
goto restart;
}
VI_LOCK(vp);
}
TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) {
if (bp->b_lblkno < trunclbn)
continue;
if (BUF_LOCK(bp,
LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
VI_MTX(vp)) == ENOLCK)
goto restart;
bremfree(bp);
bp->b_flags |= (B_INVAL | B_RELBUF);
bp->b_flags &= ~B_ASYNC;
brelse(bp);
anyfreed = 1;
if (nbp != NULL &&
(((nbp->b_xflags & BX_VNDIRTY) == 0) ||
(nbp->b_vp != vp) ||
(nbp->b_flags & B_DELWRI) == 0)) {
goto restart;
}
VI_LOCK(vp);
}
}
if (length > 0) {
restartsync:
TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) {
if (bp->b_lblkno > 0)
continue;
/*
* Since we hold the vnode lock this should only
* fail if we're racing with the buf daemon.
*/
if (BUF_LOCK(bp,
LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
VI_MTX(vp)) == ENOLCK) {
goto restart;
}
VNASSERT((bp->b_flags & B_DELWRI), vp,
("buf(%p) on dirty queue without DELWRI", bp));
bremfree(bp);
bawrite(bp);
VI_LOCK(vp);
goto restartsync;
}
}
bufobj_wwait(bo, 0, 0);
VI_UNLOCK(vp);
vnode_pager_setsize(vp, length);
return (0);
}
/*
* buf_splay() - splay tree core for the clean/dirty list of buffers in
* a vnode.
*
* NOTE: We have to deal with the special case of a background bitmap
* buffer, a situation where two buffers will have the same logical
* block offset. We want (1) only the foreground buffer to be accessed
* in a lookup and (2) must differentiate between the foreground and
* background buffer in the splay tree algorithm because the splay
* tree cannot normally handle multiple entities with the same 'index'.
* We accomplish this by adding differentiating flags to the splay tree's
* numerical domain.
*/
static
struct buf *
buf_splay(daddr_t lblkno, b_xflags_t xflags, struct buf *root)
{
struct buf dummy;
struct buf *lefttreemax, *righttreemin, *y;
if (root == NULL)
return (NULL);
lefttreemax = righttreemin = &dummy;
for (;;) {
if (lblkno < root->b_lblkno ||
(lblkno == root->b_lblkno &&
(xflags & BX_BKGRDMARKER) < (root->b_xflags & BX_BKGRDMARKER))) {
if ((y = root->b_left) == NULL)
break;
if (lblkno < y->b_lblkno) {
/* Rotate right. */
root->b_left = y->b_right;
y->b_right = root;
root = y;
if ((y = root->b_left) == NULL)
break;
}
/* Link into the new root's right tree. */
righttreemin->b_left = root;
righttreemin = root;
} else if (lblkno > root->b_lblkno ||
(lblkno == root->b_lblkno &&
(xflags & BX_BKGRDMARKER) > (root->b_xflags & BX_BKGRDMARKER))) {
if ((y = root->b_right) == NULL)
break;
if (lblkno > y->b_lblkno) {
/* Rotate left. */
root->b_right = y->b_left;
y->b_left = root;
root = y;
if ((y = root->b_right) == NULL)
break;
}
/* Link into the new root's left tree. */
lefttreemax->b_right = root;
lefttreemax = root;
} else {
break;
}
root = y;
}
/* Assemble the new root. */
lefttreemax->b_right = root->b_left;
righttreemin->b_left = root->b_right;
root->b_left = dummy.b_right;
root->b_right = dummy.b_left;
return (root);
}
static void
buf_vlist_remove(struct buf *bp)
{
struct buf *root;
struct bufv *bv;
KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp));
ASSERT_BO_LOCKED(bp->b_bufobj);
KASSERT((bp->b_xflags & (BX_VNDIRTY|BX_VNCLEAN)) !=
(BX_VNDIRTY|BX_VNCLEAN),
("buf_vlist_remove: Buf %p is on two lists", bp));
if (bp->b_xflags & BX_VNDIRTY)
bv = &bp->b_bufobj->bo_dirty;
else
bv = &bp->b_bufobj->bo_clean;
if (bp != bv->bv_root) {
root = buf_splay(bp->b_lblkno, bp->b_xflags, bv->bv_root);
KASSERT(root == bp, ("splay lookup failed in remove"));
}
if (bp->b_left == NULL) {
root = bp->b_right;
} else {
root = buf_splay(bp->b_lblkno, bp->b_xflags, bp->b_left);
root->b_right = bp->b_right;
}
bv->bv_root = root;
TAILQ_REMOVE(&bv->bv_hd, bp, b_bobufs);
bv->bv_cnt--;
bp->b_xflags &= ~(BX_VNDIRTY | BX_VNCLEAN);
}
/*
* Add the buffer to the sorted clean or dirty block list using a
* splay tree algorithm.
*
* NOTE: xflags is passed as a constant, optimizing this inline function!
*/
static void
buf_vlist_add(struct buf *bp, struct bufobj *bo, b_xflags_t xflags)
{
struct buf *root;
struct bufv *bv;
ASSERT_BO_LOCKED(bo);
KASSERT((bp->b_xflags & (BX_VNDIRTY|BX_VNCLEAN)) == 0,
("buf_vlist_add: Buf %p has existing xflags %d", bp, bp->b_xflags));
bp->b_xflags |= xflags;
if (xflags & BX_VNDIRTY)
bv = &bo->bo_dirty;
else
bv = &bo->bo_clean;
root = buf_splay(bp->b_lblkno, bp->b_xflags, bv->bv_root);
if (root == NULL) {
bp->b_left = NULL;
bp->b_right = NULL;
TAILQ_INSERT_TAIL(&bv->bv_hd, bp, b_bobufs);
} else if (bp->b_lblkno < root->b_lblkno ||
(bp->b_lblkno == root->b_lblkno &&
(bp->b_xflags & BX_BKGRDMARKER) < (root->b_xflags & BX_BKGRDMARKER))) {
bp->b_left = root->b_left;
bp->b_right = root;
root->b_left = NULL;
TAILQ_INSERT_BEFORE(root, bp, b_bobufs);
} else {
bp->b_right = root->b_right;
bp->b_left = root;
root->b_right = NULL;
TAILQ_INSERT_AFTER(&bv->bv_hd, root, bp, b_bobufs);
}
bv->bv_cnt++;
bv->bv_root = bp;
}
/*
* Lookup a buffer using the splay tree. Note that we specifically avoid
* shadow buffers used in background bitmap writes.
*
* This code isn't quite efficient as it could be because we are maintaining
* two sorted lists and do not know which list the block resides in.
*
* During a "make buildworld" the desired buffer is found at one of
* the roots more than 60% of the time. Thus, checking both roots
* before performing either splay eliminates unnecessary splays on the
* first tree splayed.
*/
struct buf *
gbincore(struct bufobj *bo, daddr_t lblkno)
{
struct buf *bp;
ASSERT_BO_LOCKED(bo);
if ((bp = bo->bo_clean.bv_root) != NULL &&
bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
return (bp);
if ((bp = bo->bo_dirty.bv_root) != NULL &&
bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
return (bp);
if ((bp = bo->bo_clean.bv_root) != NULL) {
bo->bo_clean.bv_root = bp = buf_splay(lblkno, 0, bp);
if (bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
return (bp);
}
if ((bp = bo->bo_dirty.bv_root) != NULL) {
bo->bo_dirty.bv_root = bp = buf_splay(lblkno, 0, bp);
if (bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
return (bp);
}
return (NULL);
}
/*
* Associate a buffer with a vnode.
*/
void
bgetvp(struct vnode *vp, struct buf *bp)
{
VNASSERT(bp->b_vp == NULL, bp->b_vp, ("bgetvp: not free"));
CTR3(KTR_BUF, "bgetvp(%p) vp %p flags %X", bp, vp, bp->b_flags);
VNASSERT((bp->b_xflags & (BX_VNDIRTY|BX_VNCLEAN)) == 0, vp,
("bgetvp: bp already attached! %p", bp));
ASSERT_VI_LOCKED(vp, "bgetvp");
vholdl(vp);
bp->b_vp = vp;
bp->b_bufobj = &vp->v_bufobj;
/*
* Insert onto list for new vnode.
*/
buf_vlist_add(bp, &vp->v_bufobj, BX_VNCLEAN);
}
/*
* Disassociate a buffer from a vnode.
*/
void
brelvp(struct buf *bp)
{
struct bufobj *bo;
struct vnode *vp;
CTR3(KTR_BUF, "brelvp(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags);
KASSERT(bp->b_vp != NULL, ("brelvp: NULL"));
/*
* Delete from old vnode list, if on one.
*/
vp = bp->b_vp; /* XXX */
bo = bp->b_bufobj;
BO_LOCK(bo);
if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN))
buf_vlist_remove(bp);
else
panic("brelvp: Buffer %p not on queue.", bp);
if ((bo->bo_flag & BO_ONWORKLST) && bo->bo_dirty.bv_cnt == 0) {
bo->bo_flag &= ~BO_ONWORKLST;
mtx_lock(&sync_mtx);
LIST_REMOVE(bo, bo_synclist);
syncer_worklist_len--;
mtx_unlock(&sync_mtx);
}
bp->b_vp = NULL;
bp->b_bufobj = NULL;
vdropl(vp);
}
/*
* Add an item to the syncer work queue.
*/
static void
vn_syncer_add_to_worklist(struct bufobj *bo, int delay)
{
int slot;
ASSERT_BO_LOCKED(bo);
mtx_lock(&sync_mtx);
if (bo->bo_flag & BO_ONWORKLST)
LIST_REMOVE(bo, bo_synclist);
else {
bo->bo_flag |= BO_ONWORKLST;
syncer_worklist_len++;
}
if (delay > syncer_maxdelay - 2)
delay = syncer_maxdelay - 2;
slot = (syncer_delayno + delay) & syncer_mask;
LIST_INSERT_HEAD(&syncer_workitem_pending[slot], bo, bo_synclist);
mtx_unlock(&sync_mtx);
}
static int
sysctl_vfs_worklist_len(SYSCTL_HANDLER_ARGS)
{
int error, len;
mtx_lock(&sync_mtx);
len = syncer_worklist_len - sync_vnode_count;
mtx_unlock(&sync_mtx);
error = SYSCTL_OUT(req, &len, sizeof(len));
return (error);
}
SYSCTL_PROC(_vfs, OID_AUTO, worklist_len, CTLTYPE_INT | CTLFLAG_RD, NULL, 0,
sysctl_vfs_worklist_len, "I", "Syncer thread worklist length");
static struct proc *updateproc;
static void sched_sync(void);
static struct kproc_desc up_kp = {
"syncer",
sched_sync,
&updateproc
};
SYSINIT(syncer, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &up_kp)
static int
sync_vnode(struct bufobj *bo, struct thread *td)
{
struct vnode *vp;
struct mount *mp;
vp = bo->__bo_vnode; /* XXX */
if (VOP_ISLOCKED(vp, NULL) != 0)
return (1);
if (VI_TRYLOCK(vp) == 0)
return (1);
/*
* We use vhold in case the vnode does not
* successfully sync. vhold prevents the vnode from
* going away when we unlock the sync_mtx so that
* we can acquire the vnode interlock.
*/
vholdl(vp);
mtx_unlock(&sync_mtx);
VI_UNLOCK(vp);
if (vn_start_write(vp, &mp, V_NOWAIT) != 0) {
vdrop(vp);
mtx_lock(&sync_mtx);
return (1);
}
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
(void) VOP_FSYNC(vp, MNT_LAZY, td);
VOP_UNLOCK(vp, 0, td);
vn_finished_write(mp);
VI_LOCK(vp);
if ((bo->bo_flag & BO_ONWORKLST) != 0) {
/*
* Put us back on the worklist. The worklist
* routine will remove us from our current
* position and then add us back in at a later
* position.
*/
vn_syncer_add_to_worklist(bo, syncdelay);
}
vdropl(vp);
mtx_lock(&sync_mtx);
return (0);
}
/*
* System filesystem synchronizer daemon.
*/
static void
sched_sync(void)
{
struct synclist *next;
struct synclist *slp;
struct bufobj *bo;
long starttime;
struct thread *td = FIRST_THREAD_IN_PROC(updateproc);
static int dummychan;
int last_work_seen;
int net_worklist_len;
int syncer_final_iter;
int first_printf;
int error;
mtx_lock(&Giant);
last_work_seen = 0;
syncer_final_iter = 0;
first_printf = 1;
syncer_state = SYNCER_RUNNING;
starttime = time_uptime;
td->td_pflags |= TDP_NORUNNINGBUF;
EVENTHANDLER_REGISTER(shutdown_pre_sync, syncer_shutdown, td->td_proc,
SHUTDOWN_PRI_LAST);
for (;;) {
mtx_lock(&sync_mtx);
if (syncer_state == SYNCER_FINAL_DELAY &&
syncer_final_iter == 0) {
mtx_unlock(&sync_mtx);
kthread_suspend_check(td->td_proc);
mtx_lock(&sync_mtx);
}
net_worklist_len = syncer_worklist_len - sync_vnode_count;
if (syncer_state != SYNCER_RUNNING &&
starttime != time_uptime) {
if (first_printf) {
printf("\nSyncing disks, vnodes remaining...");
first_printf = 0;
}
printf("%d ", net_worklist_len);
}
starttime = time_uptime;
/*
* Push files whose dirty time has expired. Be careful
* of interrupt race on slp queue.
*
* Skip over empty worklist slots when shutting down.
*/
do {
slp = &syncer_workitem_pending[syncer_delayno];
syncer_delayno += 1;
if (syncer_delayno == syncer_maxdelay)
syncer_delayno = 0;
next = &syncer_workitem_pending[syncer_delayno];
/*
* If the worklist has wrapped since the
* it was emptied of all but syncer vnodes,
* switch to the FINAL_DELAY state and run
* for one more second.
*/
if (syncer_state == SYNCER_SHUTTING_DOWN &&
net_worklist_len == 0 &&
last_work_seen == syncer_delayno) {
syncer_state = SYNCER_FINAL_DELAY;
syncer_final_iter = SYNCER_SHUTDOWN_SPEEDUP;
}
} while (syncer_state != SYNCER_RUNNING && LIST_EMPTY(slp) &&
syncer_worklist_len > 0);
/*
* Keep track of the last time there was anything
* on the worklist other than syncer vnodes.
* Return to the SHUTTING_DOWN state if any
* new work appears.
*/
if (net_worklist_len > 0 || syncer_state == SYNCER_RUNNING)
last_work_seen = syncer_delayno;
if (net_worklist_len > 0 && syncer_state == SYNCER_FINAL_DELAY)
syncer_state = SYNCER_SHUTTING_DOWN;
while ((bo = LIST_FIRST(slp)) != NULL) {
error = sync_vnode(bo, td);
if (error == 1) {
LIST_REMOVE(bo, bo_synclist);
LIST_INSERT_HEAD(next, bo, bo_synclist);
continue;
}
}
if (syncer_state == SYNCER_FINAL_DELAY && syncer_final_iter > 0)
syncer_final_iter--;
mtx_unlock(&sync_mtx);
/*
* Do soft update processing.
*/
if (softdep_process_worklist_hook != NULL)
(*softdep_process_worklist_hook)(NULL);
/*
* 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.
*/
mtx_lock(&sync_mtx);
if (rushjob > 0) {
rushjob -= 1;
mtx_unlock(&sync_mtx);
continue;
}
mtx_unlock(&sync_mtx);
/*
* Just sleep for a short period if time between
* iterations when shutting down to allow some I/O
* to happen.
*
* If it has taken us less than a second to process the
* current work, then wait. Otherwise start right over
* again. We can still lose time if any single round
* takes more than two seconds, but it does not really
* matter as we are just trying to generally pace the
* filesystem activity.
*/
if (syncer_state != SYNCER_RUNNING)
tsleep(&dummychan, PPAUSE, "syncfnl",
hz / SYNCER_SHUTDOWN_SPEEDUP);
else if (time_uptime == starttime)
tsleep(&lbolt, PPAUSE, "syncer", 0);
}
}
/*
* Request the syncer daemon to speed up its work.
* We never push it to speed up more than half of its
* normal turn time, otherwise it could take over the cpu.
*/
int
speedup_syncer()
{
struct thread *td;
int ret = 0;
td = FIRST_THREAD_IN_PROC(updateproc);
sleepq_remove(td, &lbolt);
mtx_lock(&sync_mtx);
if (rushjob < syncdelay / 2) {
rushjob += 1;
stat_rush_requests += 1;
ret = 1;
}
mtx_unlock(&sync_mtx);
return (ret);
}
/*
* Tell the syncer to speed up its work and run though its work
* list several times, then tell it to shut down.
*/
static void
syncer_shutdown(void *arg, int howto)
{
struct thread *td;
if (howto & RB_NOSYNC)
return;
td = FIRST_THREAD_IN_PROC(updateproc);
sleepq_remove(td, &lbolt);
mtx_lock(&sync_mtx);
syncer_state = SYNCER_SHUTTING_DOWN;
rushjob = 0;
mtx_unlock(&sync_mtx);
kproc_shutdown(arg, howto);
}
/*
* Reassign a buffer from one vnode to another.
* Used to assign file specific control information
* (indirect blocks) to the vnode to which they belong.
*/
void
reassignbuf(struct buf *bp)
{
struct vnode *vp;
struct bufobj *bo;
int delay;
#ifdef INVARIANTS
struct bufv *bv;
#endif
vp = bp->b_vp;
bo = bp->b_bufobj;
++reassignbufcalls;
CTR3(KTR_BUF, "reassignbuf(%p) vp %p flags %X",
bp, bp->b_vp, bp->b_flags);
/*
* B_PAGING flagged buffers cannot be reassigned because their vp
* is not fully linked in.
*/
if (bp->b_flags & B_PAGING)
panic("cannot reassign paging buffer");
/*
* Delete from old vnode list, if on one.
*/
VI_LOCK(vp);
if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN))
buf_vlist_remove(bp);
else
panic("reassignbuf: Buffer %p not on queue.", bp);
/*
* If dirty, put on list of dirty buffers; otherwise insert onto list
* of clean buffers.
*/
if (bp->b_flags & B_DELWRI) {
if ((bo->bo_flag & BO_ONWORKLST) == 0) {
switch (vp->v_type) {
case VDIR:
delay = dirdelay;
break;
case VCHR:
delay = metadelay;
break;
default:
delay = filedelay;
}
vn_syncer_add_to_worklist(bo, delay);
}
buf_vlist_add(bp, bo, BX_VNDIRTY);
} else {
buf_vlist_add(bp, bo, BX_VNCLEAN);
if ((bo->bo_flag & BO_ONWORKLST) && bo->bo_dirty.bv_cnt == 0) {
mtx_lock(&sync_mtx);
LIST_REMOVE(bo, bo_synclist);
syncer_worklist_len--;
mtx_unlock(&sync_mtx);
bo->bo_flag &= ~BO_ONWORKLST;
}
}
#ifdef INVARIANTS
bv = &bo->bo_clean;
bp = TAILQ_FIRST(&bv->bv_hd);
KASSERT(bp == NULL || bp->b_bufobj == bo,
("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
bp = TAILQ_LAST(&bv->bv_hd, buflists);
KASSERT(bp == NULL || bp->b_bufobj == bo,
("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
bv = &bo->bo_dirty;
bp = TAILQ_FIRST(&bv->bv_hd);
KASSERT(bp == NULL || bp->b_bufobj == bo,
("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
bp = TAILQ_LAST(&bv->bv_hd, buflists);
KASSERT(bp == NULL || bp->b_bufobj == bo,
("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
#endif
VI_UNLOCK(vp);
}
/*
* Increment the use and hold counts on the vnode, taking care to reference
* the driver's usecount if this is a chardev. The vholdl() will remove
* the vnode from the free list if it is presently free. Requires the
* vnode interlock and returns with it held.
*/
static void
v_incr_usecount(struct vnode *vp)
{
CTR3(KTR_VFS, "v_incr_usecount: vp %p holdcnt %d usecount %d\n",
vp, vp->v_holdcnt, vp->v_usecount);
vp->v_usecount++;
if (vp->v_type == VCHR && vp->v_rdev != NULL) {
dev_lock();
vp->v_rdev->si_usecount++;
dev_unlock();
}
vholdl(vp);
}
/*
* Decrement the vnode use and hold count along with the driver's usecount
* if this is a chardev. The vdropl() below releases the vnode interlock
* as it may free the vnode.
*/
static void
v_decr_usecount(struct vnode *vp)
{
CTR3(KTR_VFS, "v_decr_usecount: vp %p holdcnt %d usecount %d\n",
vp, vp->v_holdcnt, vp->v_usecount);
ASSERT_VI_LOCKED(vp, __FUNCTION__);
VNASSERT(vp->v_usecount > 0, vp,
("v_decr_usecount: negative usecount"));
vp->v_usecount--;
if (vp->v_type == VCHR && vp->v_rdev != NULL) {
dev_lock();
vp->v_rdev->si_usecount--;
dev_unlock();
}
vdropl(vp);
}
/*
* Decrement only the use count and driver use count. This is intended to
* be paired with a follow on vdropl() to release the remaining hold count.
* In this way we may vgone() a vnode with a 0 usecount without risk of
* having it end up on a free list because the hold count is kept above 0.
*/
static void
v_decr_useonly(struct vnode *vp)
{
CTR3(KTR_VFS, "v_decr_useonly: vp %p holdcnt %d usecount %d\n",
vp, vp->v_holdcnt, vp->v_usecount);
ASSERT_VI_LOCKED(vp, __FUNCTION__);
VNASSERT(vp->v_usecount > 0, vp,
("v_decr_useonly: negative usecount"));
vp->v_usecount--;
if (vp->v_type == VCHR && vp->v_rdev != NULL) {
dev_lock();
vp->v_rdev->si_usecount--;
dev_unlock();
}
}
/*
* Grab a particular vnode from the free list, increment its
* reference count and lock it. The vnode lock bit is set if the
* vnode is being eliminated in vgone. The process is awakened
* when the transition is completed, and an error returned to
* indicate that the vnode is no longer usable (possibly having
* been changed to a new filesystem type).
*/
int
vget(vp, flags, td)
struct vnode *vp;
int flags;
struct thread *td;
{
int oweinact;
int oldflags;
int error;
error = 0;
oldflags = flags;
oweinact = 0;
if ((flags & LK_INTERLOCK) == 0)
VI_LOCK(vp);
/*
* If the inactive call was deferred because vput() was called
* with a shared lock, we have to do it here before another thread
* gets a reference to data that should be dead.
*/
if (vp->v_iflag & VI_OWEINACT) {
if (flags & LK_NOWAIT) {
VI_UNLOCK(vp);
return (EBUSY);
}
flags &= ~LK_TYPE_MASK;
flags |= LK_EXCLUSIVE;
oweinact = 1;
}
v_incr_usecount(vp);
if ((error = vn_lock(vp, flags | LK_INTERLOCK, td)) != 0) {
VI_LOCK(vp);
/*
* must expand vrele here because we do not want
* to call VOP_INACTIVE if the reference count
* drops back to zero since it was never really
* active.
*/
v_decr_usecount(vp);
return (error);
}
if (vp->v_iflag & VI_DOOMED && (flags & LK_RETRY) == 0)
panic("vget: vn_lock failed to return ENOENT\n");
if (oweinact) {
VI_LOCK(vp);
if (vp->v_iflag & VI_OWEINACT)
vinactive(vp, td);
VI_UNLOCK(vp);
if ((oldflags & LK_TYPE_MASK) == 0)
VOP_UNLOCK(vp, 0, td);
}
return (0);
}
/*
* Increase the reference count of a vnode.
*/
void
vref(struct vnode *vp)
{
VI_LOCK(vp);
v_incr_usecount(vp);
VI_UNLOCK(vp);
}
/*
* Return reference count of a vnode.
*
* The results of this call are only guaranteed when some mechanism other
* than the VI lock is used to stop other processes from gaining references
* to the vnode. This may be the case if the caller holds the only reference.
* This is also useful when stale data is acceptable as race conditions may
* be accounted for by some other means.
*/
int
vrefcnt(struct vnode *vp)
{
int usecnt;
VI_LOCK(vp);
usecnt = vp->v_usecount;
VI_UNLOCK(vp);
return (usecnt);
}
/*
* Vnode put/release.
* If count drops to zero, call inactive routine and return to freelist.
*/
void
vrele(vp)
struct vnode *vp;
{
struct thread *td = curthread; /* XXX */
KASSERT(vp != NULL, ("vrele: null vp"));
VI_LOCK(vp);
/* Skip this v_writecount check if we're going to panic below. */
VNASSERT(vp->v_writecount < vp->v_usecount || vp->v_usecount < 1, vp,
("vrele: missed vn_close"));
if (vp->v_usecount > 1 || ((vp->v_iflag & VI_DOINGINACT) &&
vp->v_usecount == 1)) {
v_decr_usecount(vp);
return;
}
if (vp->v_usecount != 1) {
#ifdef DIAGNOSTIC
vprint("vrele: negative ref count", vp);
#endif
VI_UNLOCK(vp);
panic("vrele: negative ref cnt");
}
/*
* We want to hold the vnode until the inactive finishes to
* prevent vgone() races. We drop the use count here and the
* hold count below when we're done.
*/
v_decr_useonly(vp);
/*
* We must call VOP_INACTIVE with the node locked. Mark
* as VI_DOINGINACT to avoid recursion.
*/
if (vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK, td) == 0) {
VI_LOCK(vp);
vinactive(vp, td);
VOP_UNLOCK(vp, 0, td);
} else
VI_LOCK(vp);
vdropl(vp);
}
/*
* Release an already locked vnode. This give the same effects as
* unlock+vrele(), but takes less time and avoids releasing and
* re-aquiring the lock (as vrele() aquires the lock internally.)
*/
void
vput(vp)
struct vnode *vp;
{
struct thread *td = curthread; /* XXX */
int error;
KASSERT(vp != NULL, ("vput: null vp"));
ASSERT_VOP_LOCKED(vp, "vput");
VI_LOCK(vp);
/* Skip this v_writecount check if we're going to panic below. */
VNASSERT(vp->v_writecount < vp->v_usecount || vp->v_usecount < 1, vp,
("vput: missed vn_close"));
error = 0;
if (vp->v_usecount > 1 || ((vp->v_iflag & VI_DOINGINACT) &&
vp->v_usecount == 1)) {
VOP_UNLOCK(vp, 0, td);
v_decr_usecount(vp);
return;
}
if (vp->v_usecount != 1) {
#ifdef DIAGNOSTIC
vprint("vput: negative ref count", vp);
#endif
panic("vput: negative ref cnt");
}
/*
* We want to hold the vnode until the inactive finishes to
* prevent vgone() races. We drop the use count here and the
* hold count below when we're done.
*/
v_decr_useonly(vp);
vp->v_iflag |= VI_OWEINACT;
if (VOP_ISLOCKED(vp, NULL) != LK_EXCLUSIVE) {
error = VOP_LOCK(vp, LK_EXCLUPGRADE|LK_INTERLOCK|LK_NOWAIT, td);
VI_LOCK(vp);
if (error)
goto done;
}
if (vp->v_iflag & VI_OWEINACT)
vinactive(vp, td);
VOP_UNLOCK(vp, 0, td);
done:
vdropl(vp);
}
/*
* Somebody doesn't want the vnode recycled.
*/
void
vhold(struct vnode *vp)
{
VI_LOCK(vp);
vholdl(vp);
VI_UNLOCK(vp);
}
void
vholdl(struct vnode *vp)
{
vp->v_holdcnt++;
if (VSHOULDBUSY(vp))
vbusy(vp);
}
/*
* Note that there is one less who cares about this vnode. vdrop() is the
* opposite of vhold().
*/
void
vdrop(struct vnode *vp)
{
VI_LOCK(vp);
vdropl(vp);
}
/*
* Drop the hold count of the vnode. If this is the last reference to
* the vnode we will free it if it has been vgone'd otherwise it is
* placed on the free list.
*/
static void
vdropl(struct vnode *vp)
{
if (vp->v_holdcnt <= 0)
panic("vdrop: holdcnt %d", vp->v_holdcnt);
vp->v_holdcnt--;
if (vp->v_holdcnt == 0) {
if (vp->v_iflag & VI_DOOMED) {
vdestroy(vp);
return;
} else
vfree(vp);
}
VI_UNLOCK(vp);
}
/*
* Call VOP_INACTIVE on the vnode and manage the DOINGINACT and OWEINACT
* flags. DOINGINACT prevents us from recursing in calls to vinactive.
* OWEINACT tracks whether a vnode missed a call to inactive due to a
* failed lock upgrade.
*/
static void
vinactive(struct vnode *vp, struct thread *td)
{
ASSERT_VOP_LOCKED(vp, "vinactive");
ASSERT_VI_LOCKED(vp, "vinactive");
VNASSERT((vp->v_iflag & VI_DOINGINACT) == 0, vp,
("vinactive: recursed on VI_DOINGINACT"));
vp->v_iflag |= VI_DOINGINACT;
vp->v_iflag &= ~VI_OWEINACT;
VI_UNLOCK(vp);
VOP_INACTIVE(vp, td);
VI_LOCK(vp);
VNASSERT(vp->v_iflag & VI_DOINGINACT, vp,
("vinactive: lost VI_DOINGINACT"));
vp->v_iflag &= ~VI_DOINGINACT;
}
/*
* Remove any vnodes in the vnode table belonging to mount point mp.
*
* If FORCECLOSE is not 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 FORCECLOSE is specified, detach any active vnodes
* that are found.
*
* If WRITECLOSE is set, only flush out regular file vnodes open for
* writing.
*
* SKIPSYSTEM causes any vnodes marked VV_SYSTEM to be skipped.
*
* `rootrefs' specifies the base reference count for the root vnode
* of this filesystem. The root vnode is considered busy if its
* v_usecount exceeds this value. On a successful return, vflush(, td)
* will call vrele() on the root vnode exactly rootrefs times.
* If the SKIPSYSTEM or WRITECLOSE flags are specified, rootrefs must
* be zero.
*/
#ifdef DIAGNOSTIC
static int busyprt = 0; /* print out busy vnodes */
SYSCTL_INT(_debug, OID_AUTO, busyprt, CTLFLAG_RW, &busyprt, 0, "");
#endif
int
vflush(mp, rootrefs, flags, td)
struct mount *mp;
int rootrefs;
int flags;
struct thread *td;
{
struct vnode *vp, *nvp, *rootvp = NULL;
struct vattr vattr;
int busy = 0, error;
CTR1(KTR_VFS, "vflush: mp %p", mp);
if (rootrefs > 0) {
KASSERT((flags & (SKIPSYSTEM | WRITECLOSE)) == 0,
("vflush: bad args"));
/*
* Get the filesystem root vnode. We can vput() it
* immediately, since with rootrefs > 0, it won't go away.
*/
if ((error = VFS_ROOT(mp, LK_EXCLUSIVE, &rootvp, td)) != 0)
return (error);
vput(rootvp);
}
MNT_ILOCK(mp);
loop:
MNT_VNODE_FOREACH(vp, mp, nvp) {
VI_LOCK(vp);
vholdl(vp);
MNT_IUNLOCK(mp);
error = vn_lock(vp, LK_INTERLOCK | LK_EXCLUSIVE, td);
if (error) {
vdrop(vp);
MNT_ILOCK(mp);
goto loop;
}
/*
* Skip over a vnodes marked VV_SYSTEM.
*/
if ((flags & SKIPSYSTEM) && (vp->v_vflag & VV_SYSTEM)) {
VOP_UNLOCK(vp, 0, td);
vdrop(vp);
MNT_ILOCK(mp);
continue;
}
/*
* If WRITECLOSE is set, flush out unlinked but still open
* files (even if open only for reading) and regular file
* vnodes open for writing.
*/
if (flags & WRITECLOSE) {
error = VOP_GETATTR(vp, &vattr, td->td_ucred, td);
VI_LOCK(vp);
if ((vp->v_type == VNON ||
(error == 0 && vattr.va_nlink > 0)) &&
(vp->v_writecount == 0 || vp->v_type != VREG)) {
VOP_UNLOCK(vp, 0, td);
vdropl(vp);
MNT_ILOCK(mp);
continue;
}
} else
VI_LOCK(vp);
/*
* With v_usecount == 0, all we need to do is clear out the
* vnode data structures and we are done.
*
* If FORCECLOSE is set, forcibly close the vnode.
*/
if (vp->v_usecount == 0 || (flags & FORCECLOSE)) {
VNASSERT(vp->v_usecount == 0 ||
(vp->v_type != VCHR && vp->v_type != VBLK), vp,
("device VNODE %p is FORCECLOSED", vp));
vgonel(vp);
} else {
busy++;
#ifdef DIAGNOSTIC
if (busyprt)
vprint("vflush: busy vnode", vp);
#endif
}
VOP_UNLOCK(vp, 0, td);
vdropl(vp);
MNT_ILOCK(mp);
}
MNT_IUNLOCK(mp);
if (rootrefs > 0 && (flags & FORCECLOSE) == 0) {
/*
* If just the root vnode is busy, and if its refcount
* is equal to `rootrefs', then go ahead and kill it.
*/
VI_LOCK(rootvp);
KASSERT(busy > 0, ("vflush: not busy"));
VNASSERT(rootvp->v_usecount >= rootrefs, rootvp,
("vflush: usecount %d < rootrefs %d",
rootvp->v_usecount, rootrefs));
if (busy == 1 && rootvp->v_usecount == rootrefs) {
VOP_LOCK(rootvp, LK_EXCLUSIVE|LK_INTERLOCK, td);
vgone(rootvp);
VOP_UNLOCK(rootvp, 0, td);
busy = 0;
} else
VI_UNLOCK(rootvp);
}
if (busy)
return (EBUSY);
for (; rootrefs > 0; rootrefs--)
vrele(rootvp);
return (0);
}
/*
* Recycle an unused vnode to the front of the free list.
*/
int
vrecycle(struct vnode *vp, struct thread *td)
{
int recycled;
ASSERT_VOP_LOCKED(vp, "vrecycle");
recycled = 0;
VI_LOCK(vp);
if (vp->v_usecount == 0) {
recycled = 1;
vgonel(vp);
}
VI_UNLOCK(vp);
return (recycled);
}
/*
* Eliminate all activity associated with a vnode
* in preparation for reuse.
*/
void
vgone(struct vnode *vp)
{
VI_LOCK(vp);
vgonel(vp);
VI_UNLOCK(vp);
}
/*
* vgone, with the vp interlock held.
*/
void
vgonel(struct vnode *vp)
{
struct thread *td;
int oweinact;
int active;
CTR1(KTR_VFS, "vgonel: vp %p", vp);
ASSERT_VOP_LOCKED(vp, "vgonel");
ASSERT_VI_LOCKED(vp, "vgonel");
#if 0
/* XXX Need to fix ttyvp before I enable this. */
VNASSERT(vp->v_holdcnt, vp,
("vgonel: vp %p has no reference.", vp));
#endif
td = curthread;
/*
* Don't vgonel if we're already doomed.
*/
if (vp->v_iflag & VI_DOOMED)
return;
vp->v_iflag |= VI_DOOMED;
/*
* Check to see if the vnode is in use. If so, we have to call
* VOP_CLOSE() and VOP_INACTIVE().
*/
active = vp->v_usecount;
oweinact = (vp->v_iflag & VI_OWEINACT);
VI_UNLOCK(vp);
/*
* Clean out any buffers associated with the vnode.
* If the flush fails, just toss the buffers.
*/
if (!TAILQ_EMPTY(&vp->v_bufobj.bo_dirty.bv_hd))
(void) vn_write_suspend_wait(vp, NULL, V_WAIT);
if (vinvalbuf(vp, V_SAVE, td, 0, 0) != 0)
vinvalbuf(vp, 0, td, 0, 0);
/*
* If purging an active vnode, it must be closed and
* deactivated before being reclaimed.
*/
if (active)
VOP_CLOSE(vp, FNONBLOCK, NOCRED, td);
if (oweinact || active) {
VI_LOCK(vp);
if ((vp->v_iflag & VI_DOINGINACT) == 0)
vinactive(vp, td);
VI_UNLOCK(vp);
}
/*
* Reclaim the vnode.
*/
if (VOP_RECLAIM(vp, td))
panic("vgone: cannot reclaim");
VNASSERT(vp->v_object == NULL, vp,
("vop_reclaim left v_object vp=%p, tag=%s", vp, vp->v_tag));
/*
* Delete from old mount point vnode list.
*/
delmntque(vp);
cache_purge(vp);
/*
* Done with purge, reset to the standard lock and invalidate
* the vnode.
*/
VI_LOCK(vp);
vp->v_vnlock = &vp->v_lock;
vp->v_op = &dead_vnodeops;
vp->v_tag = "none";
vp->v_type = VBAD;
}
/*
* Calculate the total number of references to a special device.
*/
int
vcount(vp)
struct vnode *vp;
{
int count;
dev_lock();
count = vp->v_rdev->si_usecount;
dev_unlock();
return (count);
}
/*
* Same as above, but using the struct cdev *as argument
*/
int
count_dev(dev)
struct cdev *dev;
{
int count;
dev_lock();
count = dev->si_usecount;
dev_unlock();
return(count);
}
/*
* Print out a description of a vnode.
*/
static char *typename[] =
{"VNON", "VREG", "VDIR", "VBLK", "VCHR", "VLNK", "VSOCK", "VFIFO", "VBAD"};
void
vn_printf(struct vnode *vp, const char *fmt, ...)
{
va_list ap;
char buf[96];
va_start(ap, fmt);
vprintf(fmt, ap);
va_end(ap);
printf("%p: ", (void *)vp);
printf("tag %s, type %s\n", vp->v_tag, typename[vp->v_type]);
printf(" usecount %d, writecount %d, refcount %d mountedhere %p\n",
vp->v_usecount, vp->v_writecount, vp->v_holdcnt, vp->v_mountedhere);
buf[0] = '\0';
buf[1] = '\0';
if (vp->v_vflag & VV_ROOT)
strcat(buf, "|VV_ROOT");
if (vp->v_vflag & VV_TEXT)
strcat(buf, "|VV_TEXT");
if (vp->v_vflag & VV_SYSTEM)
strcat(buf, "|VV_SYSTEM");
if (vp->v_iflag & VI_DOOMED)
strcat(buf, "|VI_DOOMED");
if (vp->v_iflag & VI_FREE)
strcat(buf, "|VI_FREE");
printf(" flags (%s)\n", buf + 1);
if (mtx_owned(VI_MTX(vp)))
printf(" VI_LOCKed");
if (vp->v_object != NULL)
printf(" v_object %p ref %d pages %d\n",
vp->v_object, vp->v_object->ref_count,
vp->v_object->resident_page_count);
printf(" ");
lockmgr_printinfo(vp->v_vnlock);
printf("\n");
if (vp->v_data != NULL)
VOP_PRINT(vp);
}
#ifdef DDB
#include <ddb/ddb.h>
/*
* List all of the locked vnodes in the system.
* Called when debugging the kernel.
*/
DB_SHOW_COMMAND(lockedvnods, lockedvnodes)
{
struct mount *mp, *nmp;
struct vnode *vp;
/*
* Note: because this is DDB, we can't obey the locking semantics
* for these structures, which means we could catch an inconsistent
* state and dereference a nasty pointer. Not much to be done
* about that.
*/
printf("Locked vnodes\n");
for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
nmp = TAILQ_NEXT(mp, mnt_list);
TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
if (VOP_ISLOCKED(vp, NULL))
vprint("", vp);
}
nmp = TAILQ_NEXT(mp, mnt_list);
}
}
#endif
/*
* Fill in a struct xvfsconf based on a struct vfsconf.
*/
static void
vfsconf2x(struct vfsconf *vfsp, struct xvfsconf *xvfsp)
{
strcpy(xvfsp->vfc_name, vfsp->vfc_name);
xvfsp->vfc_typenum = vfsp->vfc_typenum;
xvfsp->vfc_refcount = vfsp->vfc_refcount;
xvfsp->vfc_flags = vfsp->vfc_flags;
/*
* These are unused in userland, we keep them
* to not break binary compatibility.
*/
xvfsp->vfc_vfsops = NULL;
xvfsp->vfc_next = NULL;
}
/*
* Top level filesystem related information gathering.
*/
static int
sysctl_vfs_conflist(SYSCTL_HANDLER_ARGS)
{
struct vfsconf *vfsp;
struct xvfsconf xvfsp;
int error;
error = 0;
TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) {
bzero(&xvfsp, sizeof(xvfsp));
vfsconf2x(vfsp, &xvfsp);
error = SYSCTL_OUT(req, &xvfsp, sizeof xvfsp);
if (error)
break;
}
return (error);
}
SYSCTL_PROC(_vfs, OID_AUTO, conflist, CTLFLAG_RD, NULL, 0, sysctl_vfs_conflist,
"S,xvfsconf", "List of all configured filesystems");
#ifndef BURN_BRIDGES
static int sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS);
static int
vfs_sysctl(SYSCTL_HANDLER_ARGS)
{
int *name = (int *)arg1 - 1; /* XXX */
u_int namelen = arg2 + 1; /* XXX */
struct vfsconf *vfsp;
struct xvfsconf xvfsp;
printf("WARNING: userland calling deprecated sysctl, "
"please rebuild world\n");
#if 1 || defined(COMPAT_PRELITE2)
/* Resolve ambiguity between VFS_VFSCONF and VFS_GENERIC. */
if (namelen == 1)
return (sysctl_ovfs_conf(oidp, arg1, arg2, req));
#endif
switch (name[1]) {
case VFS_MAXTYPENUM:
if (namelen != 2)
return (ENOTDIR);
return (SYSCTL_OUT(req, &maxvfsconf, sizeof(int)));
case VFS_CONF:
if (namelen != 3)
return (ENOTDIR); /* overloaded */
TAILQ_FOREACH(vfsp, &vfsconf, vfc_list)
if (vfsp->vfc_typenum == name[2])
break;
if (vfsp == NULL)
return (EOPNOTSUPP);
bzero(&xvfsp, sizeof(xvfsp));
vfsconf2x(vfsp, &xvfsp);
return (SYSCTL_OUT(req, &xvfsp, sizeof(xvfsp)));
}
return (EOPNOTSUPP);
}
static SYSCTL_NODE(_vfs, VFS_GENERIC, generic, CTLFLAG_RD | CTLFLAG_SKIP,
vfs_sysctl, "Generic filesystem");
#if 1 || defined(COMPAT_PRELITE2)
static int
sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS)
{
int error;
struct vfsconf *vfsp;
struct ovfsconf ovfs;
TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) {
bzero(&ovfs, sizeof(ovfs));
ovfs.vfc_vfsops = vfsp->vfc_vfsops; /* XXX used as flag */
strcpy(ovfs.vfc_name, vfsp->vfc_name);
ovfs.vfc_index = vfsp->vfc_typenum;
ovfs.vfc_refcount = vfsp->vfc_refcount;
ovfs.vfc_flags = vfsp->vfc_flags;
error = SYSCTL_OUT(req, &ovfs, sizeof ovfs);
if (error)
return error;
}
return 0;
}
#endif /* 1 || COMPAT_PRELITE2 */
#endif /* !BURN_BRIDGES */
#define KINFO_VNODESLOP 10
#ifdef notyet
/*
* Dump vnode list (via sysctl).
*/
/* ARGSUSED */
static int
sysctl_vnode(SYSCTL_HANDLER_ARGS)
{
struct xvnode *xvn;
struct thread *td = req->td;
struct mount *mp;
struct vnode *vp;
int error, len, n;
/*
* Stale numvnodes access is not fatal here.
*/
req->lock = 0;
len = (numvnodes + KINFO_VNODESLOP) * sizeof *xvn;
if (!req->oldptr)
/* Make an estimate */
return (SYSCTL_OUT(req, 0, len));
error = sysctl_wire_old_buffer(req, 0);
if (error != 0)
return (error);
xvn = malloc(len, M_TEMP, M_ZERO | M_WAITOK);
n = 0;
mtx_lock(&mountlist_mtx);
TAILQ_FOREACH(mp, &mountlist, mnt_list) {
if (vfs_busy(mp, LK_NOWAIT, &mountlist_mtx, td))
continue;
MNT_ILOCK(mp);
TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
if (n == len)
break;
vref(vp);
xvn[n].xv_size = sizeof *xvn;
xvn[n].xv_vnode = vp;
xvn[n].xv_id = 0; /* XXX compat */
#define XV_COPY(field) xvn[n].xv_##field = vp->v_##field
XV_COPY(usecount);
XV_COPY(writecount);
XV_COPY(holdcnt);
XV_COPY(mount);
XV_COPY(numoutput);
XV_COPY(type);
#undef XV_COPY
xvn[n].xv_flag = vp->v_vflag;
switch (vp->v_type) {
case VREG:
case VDIR:
case VLNK:
break;
case VBLK:
case VCHR:
if (vp->v_rdev == NULL) {
vrele(vp);
continue;
}
xvn[n].xv_dev = dev2udev(vp->v_rdev);
break;
case VSOCK:
xvn[n].xv_socket = vp->v_socket;
break;
case VFIFO:
xvn[n].xv_fifo = vp->v_fifoinfo;
break;
case VNON:
case VBAD:
default:
/* shouldn't happen? */
vrele(vp);
continue;
}
vrele(vp);
++n;
}
MNT_IUNLOCK(mp);
mtx_lock(&mountlist_mtx);
vfs_unbusy(mp, td);
if (n == len)
break;
}
mtx_unlock(&mountlist_mtx);
error = SYSCTL_OUT(req, xvn, n * sizeof *xvn);
free(xvn, M_TEMP);
return (error);
}
SYSCTL_PROC(_kern, KERN_VNODE, vnode, CTLTYPE_OPAQUE|CTLFLAG_RD,
0, 0, sysctl_vnode, "S,xvnode", "");
#endif
/*
* Unmount all filesystems. The list is traversed in reverse order
* of mounting to avoid dependencies.
*/
void
vfs_unmountall()
{
struct mount *mp;
struct thread *td;
int error;
KASSERT(curthread != NULL, ("vfs_unmountall: NULL curthread"));
td = curthread;
/*
* Since this only runs when rebooting, it is not interlocked.
*/
while(!TAILQ_EMPTY(&mountlist)) {
mp = TAILQ_LAST(&mountlist, mntlist);
error = dounmount(mp, MNT_FORCE, td);
if (error) {
TAILQ_REMOVE(&mountlist, mp, mnt_list);
/*
* XXX: Due to the way in which we mount the root
* file system off of devfs, devfs will generate a
* "busy" warning when we try to unmount it before
* the root. Don't print a warning as a result in
* order to avoid false positive errors that may
* cause needless upset.
*/
if (strcmp(mp->mnt_vfc->vfc_name, "devfs") != 0) {
printf("unmount of %s failed (",
mp->mnt_stat.f_mntonname);
if (error == EBUSY)
printf("BUSY)\n");
else
printf("%d)\n", error);
}
} else {
/* The unmount has removed mp from the mountlist */
}
}
}
/*
* perform msync on all vnodes under a mount point
* the mount point must be locked.
*/
void
vfs_msync(struct mount *mp, int flags)
{
struct vnode *vp, *nvp;
struct vm_object *obj;
int tries;
tries = 5;
MNT_ILOCK(mp);
loop:
TAILQ_FOREACH_SAFE(vp, &mp->mnt_nvnodelist, v_nmntvnodes, nvp) {
if (vp->v_mount != mp) {
if (--tries > 0)
goto loop;
break;
}
VI_LOCK(vp);
if ((vp->v_iflag & VI_OBJDIRTY) &&
(flags == MNT_WAIT || VOP_ISLOCKED(vp, NULL) == 0)) {
MNT_IUNLOCK(mp);
if (!vget(vp,
LK_EXCLUSIVE | LK_RETRY | LK_INTERLOCK,
curthread)) {
if (vp->v_vflag & VV_NOSYNC) { /* unlinked */
vput(vp);
MNT_ILOCK(mp);
continue;
}
obj = vp->v_object;
if (obj != NULL) {
VM_OBJECT_LOCK(obj);
vm_object_page_clean(obj, 0, 0,
flags == MNT_WAIT ?
OBJPC_SYNC : OBJPC_NOSYNC);
VM_OBJECT_UNLOCK(obj);
}
vput(vp);
}
MNT_ILOCK(mp);
if (TAILQ_NEXT(vp, v_nmntvnodes) != nvp) {
if (--tries > 0)
goto loop;
break;
}
} else
VI_UNLOCK(vp);
}
MNT_IUNLOCK(mp);
}
/*
* Mark a vnode as free, putting it up for recycling.
*/
static void
vfree(struct vnode *vp)
{
CTR1(KTR_VFS, "vfree vp %p", vp);
ASSERT_VI_LOCKED(vp, "vfree");
mtx_lock(&vnode_free_list_mtx);
VNASSERT(vp->v_op != NULL, vp, ("vfree: vnode already reclaimed."));
VNASSERT((vp->v_iflag & VI_FREE) == 0, vp, ("vnode already free"));
VNASSERT(VSHOULDFREE(vp), vp, ("vfree: freeing when we shouldn't"));
VNASSERT((vp->v_iflag & VI_DOOMED) == 0, vp,
("vfree: Freeing doomed vnode"));
if (vp->v_iflag & VI_AGE) {
TAILQ_INSERT_HEAD(&vnode_free_list, vp, v_freelist);
} else {
TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
}
freevnodes++;
vp->v_iflag &= ~VI_AGE;
vp->v_iflag |= VI_FREE;
mtx_unlock(&vnode_free_list_mtx);
}
/*
* Opposite of vfree() - mark a vnode as in use.
*/
static void
vbusy(struct vnode *vp)
{
CTR1(KTR_VFS, "vbusy vp %p", vp);
ASSERT_VI_LOCKED(vp, "vbusy");
VNASSERT((vp->v_iflag & VI_FREE) != 0, vp, ("vnode not free"));
VNASSERT(vp->v_op != NULL, vp, ("vbusy: vnode already reclaimed."));
mtx_lock(&vnode_free_list_mtx);
TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
freevnodes--;
vp->v_iflag &= ~(VI_FREE|VI_AGE);
mtx_unlock(&vnode_free_list_mtx);
}
/*
* Initalize per-vnode helper structure to hold poll-related state.
*/
void
v_addpollinfo(struct vnode *vp)
{
struct vpollinfo *vi;
vi = uma_zalloc(vnodepoll_zone, M_WAITOK);
if (vp->v_pollinfo != NULL) {
uma_zfree(vnodepoll_zone, vi);
return;
}
vp->v_pollinfo = vi;
mtx_init(&vp->v_pollinfo->vpi_lock, "vnode pollinfo", NULL, MTX_DEF);
knlist_init(&vp->v_pollinfo->vpi_selinfo.si_note, vp, vfs_knllock,
vfs_knlunlock, vfs_knllocked);
}
/*
* Record a process's interest in events which might happen to
* a vnode. Because poll uses the historic select-style interface
* internally, this routine serves as both the ``check for any
* pending events'' and the ``record my interest in future events''
* functions. (These are done together, while the lock is held,
* to avoid race conditions.)
*/
int
vn_pollrecord(vp, td, events)
struct vnode *vp;
struct thread *td;
short events;
{
if (vp->v_pollinfo == NULL)
v_addpollinfo(vp);
mtx_lock(&vp->v_pollinfo->vpi_lock);
if (vp->v_pollinfo->vpi_revents & events) {
/*
* This leaves events we are not interested
* in available for the other process which
* which presumably had requested them
* (otherwise they would never have been
* recorded).
*/
events &= vp->v_pollinfo->vpi_revents;
vp->v_pollinfo->vpi_revents &= ~events;
mtx_unlock(&vp->v_pollinfo->vpi_lock);
return events;
}
vp->v_pollinfo->vpi_events |= events;
selrecord(td, &vp->v_pollinfo->vpi_selinfo);
mtx_unlock(&vp->v_pollinfo->vpi_lock);
return 0;
}
/*
* Routine to create and manage a filesystem syncer vnode.
*/
#define sync_close ((int (*)(struct vop_close_args *))nullop)
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 struct vop_vector sync_vnodeops = {
.vop_bypass = VOP_EOPNOTSUPP,
.vop_close = sync_close, /* close */
.vop_fsync = sync_fsync, /* fsync */
.vop_inactive = sync_inactive, /* inactive */
.vop_reclaim = sync_reclaim, /* reclaim */
.vop_lock = vop_stdlock, /* lock */
.vop_unlock = vop_stdunlock, /* unlock */
.vop_islocked = vop_stdislocked, /* islocked */
};
/*
* Create a new filesystem syncer vnode for the specified mount point.
*/
int
vfs_allocate_syncvnode(mp)
struct mount *mp;
{
struct vnode *vp;
static long start, incr, next;
int error;
/* Allocate a new vnode */
if ((error = getnewvnode("syncer", mp, &sync_vnodeops, &vp)) != 0) {
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;
}
VI_LOCK(vp);
vn_syncer_add_to_worklist(&vp->v_bufobj,
syncdelay > 0 ? next % syncdelay : 0);
/* XXX - vn_syncer_add_to_worklist() also grabs and drops sync_mtx. */
mtx_lock(&sync_mtx);
sync_vnode_count++;
mtx_unlock(&sync_mtx);
VI_UNLOCK(vp);
mp->mnt_syncer = vp;
return (0);
}
/*
* Do a lazy sync of the filesystem.
*/
static int
sync_fsync(ap)
struct vop_fsync_args /* {
struct vnode *a_vp;
struct ucred *a_cred;
int a_waitfor;
struct thread *a_td;
} */ *ap;
{
struct vnode *syncvp = ap->a_vp;
struct mount *mp = syncvp->v_mount;
struct thread *td = ap->a_td;
int error, asyncflag;
struct bufobj *bo;
/*
* We only need to do something if this is a lazy evaluation.
*/
if (ap->a_waitfor != MNT_LAZY)
return (0);
/*
* Move ourselves to the back of the sync list.
*/
bo = &syncvp->v_bufobj;
BO_LOCK(bo);
vn_syncer_add_to_worklist(bo, syncdelay);
BO_UNLOCK(bo);
/*
* Walk the list of vnodes pushing all that are dirty and
* not already on the sync list.
*/
mtx_lock(&mountlist_mtx);
if (vfs_busy(mp, LK_EXCLUSIVE | LK_NOWAIT, &mountlist_mtx, td) != 0) {
mtx_unlock(&mountlist_mtx);
return (0);
}
if (vn_start_write(NULL, &mp, V_NOWAIT) != 0) {
vfs_unbusy(mp, td);
return (0);
}
asyncflag = mp->mnt_flag & MNT_ASYNC;
mp->mnt_flag &= ~MNT_ASYNC;
vfs_msync(mp, MNT_NOWAIT);
error = VFS_SYNC(mp, MNT_LAZY, td);
if (asyncflag)
mp->mnt_flag |= MNT_ASYNC;
vn_finished_write(mp);
vfs_unbusy(mp, td);
return (error);
}
/*
* The syncer vnode is no referenced.
*/
static int
sync_inactive(ap)
struct vop_inactive_args /* {
struct vnode *a_vp;
struct thread *a_td;
} */ *ap;
{
vgone(ap->a_vp);
return (0);
}
/*
* The syncer vnode is no longer needed and is being decommissioned.
*
* Modifications to the worklist must be protected by sync_mtx.
*/
static int
sync_reclaim(ap)
struct vop_reclaim_args /* {
struct vnode *a_vp;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
struct bufobj *bo;
VI_LOCK(vp);
bo = &vp->v_bufobj;
vp->v_mount->mnt_syncer = NULL;
if (bo->bo_flag & BO_ONWORKLST) {
mtx_lock(&sync_mtx);
LIST_REMOVE(bo, bo_synclist);
syncer_worklist_len--;
sync_vnode_count--;
mtx_unlock(&sync_mtx);
bo->bo_flag &= ~BO_ONWORKLST;
}
VI_UNLOCK(vp);
return (0);
}
/*
* Check if vnode represents a disk device
*/
int
vn_isdisk(vp, errp)
struct vnode *vp;
int *errp;
{
int error;
error = 0;
dev_lock();
if (vp->v_type != VCHR)
error = ENOTBLK;
else if (vp->v_rdev == NULL)
error = ENXIO;
else if (vp->v_rdev->si_devsw == NULL)
error = ENXIO;
else if (!(vp->v_rdev->si_devsw->d_flags & D_DISK))
error = ENOTBLK;
dev_unlock();
if (errp != NULL)
*errp = error;
return (error == 0);
}
/*
* Common filesystem object access control check routine. Accepts a
* vnode's type, "mode", uid and gid, requested access mode, credentials,
* and optional call-by-reference privused argument allowing vaccess()
* to indicate to the caller whether privilege was used to satisfy the
* request (obsoleted). Returns 0 on success, or an errno on failure.
*/
int
vaccess(type, file_mode, file_uid, file_gid, acc_mode, cred, privused)
enum vtype type;
mode_t file_mode;
uid_t file_uid;
gid_t file_gid;
mode_t acc_mode;
struct ucred *cred;
int *privused;
{
mode_t dac_granted;
#ifdef CAPABILITIES
mode_t cap_granted;
#endif
/*
* Look for a normal, non-privileged way to access the file/directory
* as requested. If it exists, go with that.
*/
if (privused != NULL)
*privused = 0;
dac_granted = 0;
/* Check the owner. */
if (cred->cr_uid == file_uid) {
dac_granted |= VADMIN;
if (file_mode & S_IXUSR)
dac_granted |= VEXEC;
if (file_mode & S_IRUSR)
dac_granted |= VREAD;
if (file_mode & S_IWUSR)
dac_granted |= (VWRITE | VAPPEND);
if ((acc_mode & dac_granted) == acc_mode)
return (0);
goto privcheck;
}
/* Otherwise, check the groups (first match) */
if (groupmember(file_gid, cred)) {
if (file_mode & S_IXGRP)
dac_granted |= VEXEC;
if (file_mode & S_IRGRP)
dac_granted |= VREAD;
if (file_mode & S_IWGRP)
dac_granted |= (VWRITE | VAPPEND);
if ((acc_mode & dac_granted) == acc_mode)
return (0);
goto privcheck;
}
/* Otherwise, check everyone else. */
if (file_mode & S_IXOTH)
dac_granted |= VEXEC;
if (file_mode & S_IROTH)
dac_granted |= VREAD;
if (file_mode & S_IWOTH)
dac_granted |= (VWRITE | VAPPEND);
if ((acc_mode & dac_granted) == acc_mode)
return (0);
privcheck:
if (!suser_cred(cred, SUSER_ALLOWJAIL)) {
/* XXX audit: privilege used */
if (privused != NULL)
*privused = 1;
return (0);
}
#ifdef CAPABILITIES
/*
* Build a capability mask to determine if the set of capabilities
* satisfies the requirements when combined with the granted mask
* from above.
* For each capability, if the capability is required, bitwise
* or the request type onto the cap_granted mask.
*/
cap_granted = 0;
if (type == VDIR) {
/*
* For directories, use CAP_DAC_READ_SEARCH to satisfy
* VEXEC requests, instead of CAP_DAC_EXECUTE.
*/
if ((acc_mode & VEXEC) && ((dac_granted & VEXEC) == 0) &&
!cap_check(cred, NULL, CAP_DAC_READ_SEARCH, SUSER_ALLOWJAIL))
cap_granted |= VEXEC;
} else {
if ((acc_mode & VEXEC) && ((dac_granted & VEXEC) == 0) &&
!cap_check(cred, NULL, CAP_DAC_EXECUTE, SUSER_ALLOWJAIL))
cap_granted |= VEXEC;
}
if ((acc_mode & VREAD) && ((dac_granted & VREAD) == 0) &&
!cap_check(cred, NULL, CAP_DAC_READ_SEARCH, SUSER_ALLOWJAIL))
cap_granted |= VREAD;
if ((acc_mode & VWRITE) && ((dac_granted & VWRITE) == 0) &&
!cap_check(cred, NULL, CAP_DAC_WRITE, SUSER_ALLOWJAIL))
cap_granted |= (VWRITE | VAPPEND);
if ((acc_mode & VADMIN) && ((dac_granted & VADMIN) == 0) &&
!cap_check(cred, NULL, CAP_FOWNER, SUSER_ALLOWJAIL))
cap_granted |= VADMIN;
if ((acc_mode & (cap_granted | dac_granted)) == acc_mode) {
/* XXX audit: privilege used */
if (privused != NULL)
*privused = 1;
return (0);
}
#endif
return ((acc_mode & VADMIN) ? EPERM : EACCES);
}
/*
* Credential check based on process requesting service, and per-attribute
* permissions.
*/
int
extattr_check_cred(struct vnode *vp, int attrnamespace,
struct ucred *cred, struct thread *td, int access)
{
/*
* Kernel-invoked always succeeds.
*/
if (cred == NOCRED)
return (0);
/*
* Do not allow privileged processes in jail to directly
* manipulate system attributes.
*
* XXX What capability should apply here?
* Probably CAP_SYS_SETFFLAG.
*/
switch (attrnamespace) {
case EXTATTR_NAMESPACE_SYSTEM:
/* Potentially should be: return (EPERM); */
return (suser_cred(cred, 0));
case EXTATTR_NAMESPACE_USER:
return (VOP_ACCESS(vp, access, cred, td));
default:
return (EPERM);
}
}
#ifdef DEBUG_VFS_LOCKS
/*
* This only exists to supress warnings from unlocked specfs accesses. It is
* no longer ok to have an unlocked VFS.
*/
#define IGNORE_LOCK(vp) ((vp)->v_type == VCHR || (vp)->v_type == VBAD)
int vfs_badlock_ddb = 1; /* Drop into debugger on violation. */
SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_ddb, CTLFLAG_RW, &vfs_badlock_ddb, 0, "");
int vfs_badlock_mutex = 1; /* Check for interlock across VOPs. */
SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_mutex, CTLFLAG_RW, &vfs_badlock_mutex, 0, "");
int vfs_badlock_print = 1; /* Print lock violations. */
SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_print, CTLFLAG_RW, &vfs_badlock_print, 0, "");
#ifdef KDB
int vfs_badlock_backtrace = 1; /* Print backtrace at lock violations. */
SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_backtrace, CTLFLAG_RW, &vfs_badlock_backtrace, 0, "");
#endif
static void
vfs_badlock(const char *msg, const char *str, struct vnode *vp)
{
#ifdef KDB
if (vfs_badlock_backtrace)
kdb_backtrace();
#endif
if (vfs_badlock_print)
printf("%s: %p %s\n", str, (void *)vp, msg);
if (vfs_badlock_ddb)
kdb_enter("lock violation");
}
void
assert_vi_locked(struct vnode *vp, const char *str)
{
if (vfs_badlock_mutex && !mtx_owned(VI_MTX(vp)))
vfs_badlock("interlock is not locked but should be", str, vp);
}
void
assert_vi_unlocked(struct vnode *vp, const char *str)
{
if (vfs_badlock_mutex && mtx_owned(VI_MTX(vp)))
vfs_badlock("interlock is locked but should not be", str, vp);
}
void
assert_vop_locked(struct vnode *vp, const char *str)
{
if (vp && !IGNORE_LOCK(vp) && VOP_ISLOCKED(vp, NULL) == 0)
vfs_badlock("is not locked but should be", str, vp);
}
void
assert_vop_unlocked(struct vnode *vp, const char *str)
{
if (vp && !IGNORE_LOCK(vp) &&
VOP_ISLOCKED(vp, curthread) == LK_EXCLUSIVE)
vfs_badlock("is locked but should not be", str, vp);
}
void
assert_vop_elocked(struct vnode *vp, const char *str)
{
if (vp && !IGNORE_LOCK(vp) &&
VOP_ISLOCKED(vp, curthread) != LK_EXCLUSIVE)
vfs_badlock("is not exclusive locked but should be", str, vp);
}
#if 0
void
assert_vop_elocked_other(struct vnode *vp, const char *str)
{
if (vp && !IGNORE_LOCK(vp) &&
VOP_ISLOCKED(vp, curthread) != LK_EXCLOTHER)
vfs_badlock("is not exclusive locked by another thread",
str, vp);
}
void
assert_vop_slocked(struct vnode *vp, const char *str)
{
if (vp && !IGNORE_LOCK(vp) &&
VOP_ISLOCKED(vp, curthread) != LK_SHARED)
vfs_badlock("is not locked shared but should be", str, vp);
}
#endif /* 0 */
#endif /* DEBUG_VFS_LOCKS */
void
vop_rename_pre(void *ap)
{
struct vop_rename_args *a = ap;
#ifdef DEBUG_VFS_LOCKS
if (a->a_tvp)
ASSERT_VI_UNLOCKED(a->a_tvp, "VOP_RENAME");
ASSERT_VI_UNLOCKED(a->a_tdvp, "VOP_RENAME");
ASSERT_VI_UNLOCKED(a->a_fvp, "VOP_RENAME");
ASSERT_VI_UNLOCKED(a->a_fdvp, "VOP_RENAME");
/* Check the source (from). */
if (a->a_tdvp != a->a_fdvp)
ASSERT_VOP_UNLOCKED(a->a_fdvp, "vop_rename: fdvp locked");
if (a->a_tvp != a->a_fvp)
ASSERT_VOP_UNLOCKED(a->a_fvp, "vop_rename: tvp locked");
/* Check the target. */
if (a->a_tvp)
ASSERT_VOP_LOCKED(a->a_tvp, "vop_rename: tvp not locked");
ASSERT_VOP_LOCKED(a->a_tdvp, "vop_rename: tdvp not locked");
#endif
if (a->a_tdvp != a->a_fdvp)
vhold(a->a_fdvp);
if (a->a_tvp != a->a_fvp)
vhold(a->a_fvp);
vhold(a->a_tdvp);
if (a->a_tvp)
vhold(a->a_tvp);
}
void
vop_strategy_pre(void *ap)
{
#ifdef DEBUG_VFS_LOCKS
struct vop_strategy_args *a;
struct buf *bp;
a = ap;
bp = a->a_bp;
/*
* Cluster ops lock their component buffers but not the IO container.
*/
if ((bp->b_flags & B_CLUSTER) != 0)
return;
if (BUF_REFCNT(bp) < 1) {
if (vfs_badlock_print)
printf(
"VOP_STRATEGY: bp is not locked but should be\n");
if (vfs_badlock_ddb)
kdb_enter("lock violation");
}
#endif
}
void
vop_lookup_pre(void *ap)
{
#ifdef DEBUG_VFS_LOCKS
struct vop_lookup_args *a;
struct vnode *dvp;
a = ap;
dvp = a->a_dvp;
ASSERT_VI_UNLOCKED(dvp, "VOP_LOOKUP");
ASSERT_VOP_LOCKED(dvp, "VOP_LOOKUP");
#endif
}
void
vop_lookup_post(void *ap, int rc)
{
#ifdef DEBUG_VFS_LOCKS
struct vop_lookup_args *a;
struct vnode *dvp;
struct vnode *vp;
a = ap;
dvp = a->a_dvp;
vp = *(a->a_vpp);
ASSERT_VI_UNLOCKED(dvp, "VOP_LOOKUP");
ASSERT_VOP_LOCKED(dvp, "VOP_LOOKUP");
if (!rc)
ASSERT_VOP_LOCKED(vp, "VOP_LOOKUP (child)");
#endif
}
void
vop_lock_pre(void *ap)
{
#ifdef DEBUG_VFS_LOCKS
struct vop_lock_args *a = ap;
if ((a->a_flags & LK_INTERLOCK) == 0)
ASSERT_VI_UNLOCKED(a->a_vp, "VOP_LOCK");
else
ASSERT_VI_LOCKED(a->a_vp, "VOP_LOCK");
#endif
}
void
vop_lock_post(void *ap, int rc)
{
#ifdef DEBUG_VFS_LOCKS
struct vop_lock_args *a = ap;
ASSERT_VI_UNLOCKED(a->a_vp, "VOP_LOCK");
if (rc == 0)
ASSERT_VOP_LOCKED(a->a_vp, "VOP_LOCK");
#endif
}
void
vop_unlock_pre(void *ap)
{
#ifdef DEBUG_VFS_LOCKS
struct vop_unlock_args *a = ap;
if (a->a_flags & LK_INTERLOCK)
ASSERT_VI_LOCKED(a->a_vp, "VOP_UNLOCK");
ASSERT_VOP_LOCKED(a->a_vp, "VOP_UNLOCK");
#endif
}
void
vop_unlock_post(void *ap, int rc)
{
#ifdef DEBUG_VFS_LOCKS
struct vop_unlock_args *a = ap;
if (a->a_flags & LK_INTERLOCK)
ASSERT_VI_UNLOCKED(a->a_vp, "VOP_UNLOCK");
#endif
}
void
vop_create_post(void *ap, int rc)
{
struct vop_create_args *a = ap;
if (!rc)
VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE);
}
void
vop_link_post(void *ap, int rc)
{
struct vop_link_args *a = ap;
if (!rc) {
VFS_KNOTE_LOCKED(a->a_vp, NOTE_LINK);
VFS_KNOTE_LOCKED(a->a_tdvp, NOTE_WRITE);
}
}
void
vop_mkdir_post(void *ap, int rc)
{
struct vop_mkdir_args *a = ap;
if (!rc)
VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE | NOTE_LINK);
}
void
vop_mknod_post(void *ap, int rc)
{
struct vop_mknod_args *a = ap;
if (!rc)
VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE);
}
void
vop_remove_post(void *ap, int rc)
{
struct vop_remove_args *a = ap;
if (!rc) {
VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE);
VFS_KNOTE_LOCKED(a->a_vp, NOTE_DELETE);
}
}
void
vop_rename_post(void *ap, int rc)
{
struct vop_rename_args *a = ap;
if (!rc) {
VFS_KNOTE_UNLOCKED(a->a_fdvp, NOTE_WRITE);
VFS_KNOTE_UNLOCKED(a->a_tdvp, NOTE_WRITE);
VFS_KNOTE_UNLOCKED(a->a_fvp, NOTE_RENAME);
if (a->a_tvp)
VFS_KNOTE_UNLOCKED(a->a_tvp, NOTE_DELETE);
}
if (a->a_tdvp != a->a_fdvp)
vdrop(a->a_fdvp);
if (a->a_tvp != a->a_fvp)
vdrop(a->a_fvp);
vdrop(a->a_tdvp);
if (a->a_tvp)
vdrop(a->a_tvp);
}
void
vop_rmdir_post(void *ap, int rc)
{
struct vop_rmdir_args *a = ap;
if (!rc) {
VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE | NOTE_LINK);
VFS_KNOTE_LOCKED(a->a_vp, NOTE_DELETE);
}
}
void
vop_setattr_post(void *ap, int rc)
{
struct vop_setattr_args *a = ap;
if (!rc)
VFS_KNOTE_LOCKED(a->a_vp, NOTE_ATTRIB);
}
void
vop_symlink_post(void *ap, int rc)
{
struct vop_symlink_args *a = ap;
if (!rc)
VFS_KNOTE_LOCKED(a->a_dvp, NOTE_WRITE);
}
static struct knlist fs_knlist;
static void
vfs_event_init(void *arg)
{
knlist_init(&fs_knlist, NULL, NULL, NULL, NULL);
}
/* XXX - correct order? */
SYSINIT(vfs_knlist, SI_SUB_VFS, SI_ORDER_ANY, vfs_event_init, NULL);
void
vfs_event_signal(fsid_t *fsid, u_int32_t event, intptr_t data __unused)
{
KNOTE_UNLOCKED(&fs_knlist, event);
}
static int filt_fsattach(struct knote *kn);
static void filt_fsdetach(struct knote *kn);
static int filt_fsevent(struct knote *kn, long hint);
struct filterops fs_filtops =
{ 0, filt_fsattach, filt_fsdetach, filt_fsevent };
static int
filt_fsattach(struct knote *kn)
{
kn->kn_flags |= EV_CLEAR;
knlist_add(&fs_knlist, kn, 0);
return (0);
}
static void
filt_fsdetach(struct knote *kn)
{
knlist_remove(&fs_knlist, kn, 0);
}
static int
filt_fsevent(struct knote *kn, long hint)
{
kn->kn_fflags |= hint;
return (kn->kn_fflags != 0);
}
static int
sysctl_vfs_ctl(SYSCTL_HANDLER_ARGS)
{
struct vfsidctl vc;
int error;
struct mount *mp;
error = SYSCTL_IN(req, &vc, sizeof(vc));
if (error)
return (error);
if (vc.vc_vers != VFS_CTL_VERS1)
return (EINVAL);
mp = vfs_getvfs(&vc.vc_fsid);
if (mp == NULL)
return (ENOENT);
/* ensure that a specific sysctl goes to the right filesystem. */
if (strcmp(vc.vc_fstypename, "*") != 0 &&
strcmp(vc.vc_fstypename, mp->mnt_vfc->vfc_name) != 0) {
return (EINVAL);
}
VCTLTOREQ(&vc, req);
return (VFS_SYSCTL(mp, vc.vc_op, req));
}
SYSCTL_PROC(_vfs, OID_AUTO, ctl, CTLFLAG_WR,
NULL, 0, sysctl_vfs_ctl, "", "Sysctl by fsid");
/*
* Function to initialize a va_filerev field sensibly.
* XXX: Wouldn't a random number make a lot more sense ??
*/
u_quad_t
init_va_filerev(void)
{
struct bintime bt;
getbinuptime(&bt);
return (((u_quad_t)bt.sec << 32LL) | (bt.frac >> 32LL));
}
static int filt_vfsread(struct knote *kn, long hint);
static int filt_vfswrite(struct knote *kn, long hint);
static int filt_vfsvnode(struct knote *kn, long hint);
static void filt_vfsdetach(struct knote *kn);
static struct filterops vfsread_filtops =
{ 1, NULL, filt_vfsdetach, filt_vfsread };
static struct filterops vfswrite_filtops =
{ 1, NULL, filt_vfsdetach, filt_vfswrite };
static struct filterops vfsvnode_filtops =
{ 1, NULL, filt_vfsdetach, filt_vfsvnode };
static void
vfs_knllock(void *arg)
{
struct vnode *vp = arg;
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, curthread);
}
static void
vfs_knlunlock(void *arg)
{
struct vnode *vp = arg;
VOP_UNLOCK(vp, 0, curthread);
}
static int
vfs_knllocked(void *arg)
{
struct vnode *vp = arg;
return (VOP_ISLOCKED(vp, curthread) == LK_EXCLUSIVE);
}
int
vfs_kqfilter(struct vop_kqfilter_args *ap)
{
struct vnode *vp = ap->a_vp;
struct knote *kn = ap->a_kn;
struct knlist *knl;
switch (kn->kn_filter) {
case EVFILT_READ:
kn->kn_fop = &vfsread_filtops;
break;
case EVFILT_WRITE:
kn->kn_fop = &vfswrite_filtops;
break;
case EVFILT_VNODE:
kn->kn_fop = &vfsvnode_filtops;
break;
default:
return (EINVAL);
}
kn->kn_hook = (caddr_t)vp;
if (vp->v_pollinfo == NULL)
v_addpollinfo(vp);
if (vp->v_pollinfo == NULL)
return (ENOMEM);
knl = &vp->v_pollinfo->vpi_selinfo.si_note;
knlist_add(knl, kn, 0);
return (0);
}
/*
* Detach knote from vnode
*/
static void
filt_vfsdetach(struct knote *kn)
{
struct vnode *vp = (struct vnode *)kn->kn_hook;
KASSERT(vp->v_pollinfo != NULL, ("Missing v_pollinfo"));
knlist_remove(&vp->v_pollinfo->vpi_selinfo.si_note, kn, 0);
}
/*ARGSUSED*/
static int
filt_vfsread(struct knote *kn, long hint)
{
struct vnode *vp = (struct vnode *)kn->kn_hook;
struct vattr va;
/*
* filesystem is gone, so set the EOF flag and schedule
* the knote for deletion.
*/
if (hint == NOTE_REVOKE) {
kn->kn_flags |= (EV_EOF | EV_ONESHOT);
return (1);
}
if (VOP_GETATTR(vp, &va, curthread->td_ucred, curthread))
return (0);
kn->kn_data = va.va_size - kn->kn_fp->f_offset;
return (kn->kn_data != 0);
}
/*ARGSUSED*/
static int
filt_vfswrite(struct knote *kn, long hint)
{
/*
* filesystem is gone, so set the EOF flag and schedule
* the knote for deletion.
*/
if (hint == NOTE_REVOKE)
kn->kn_flags |= (EV_EOF | EV_ONESHOT);
kn->kn_data = 0;
return (1);
}
static int
filt_vfsvnode(struct knote *kn, long hint)
{
if (kn->kn_sfflags & hint)
kn->kn_fflags |= hint;
if (hint == NOTE_REVOKE) {
kn->kn_flags |= EV_EOF;
return (1);
}
return (kn->kn_fflags != 0);
}
int
vfs_read_dirent(struct vop_readdir_args *ap, struct dirent *dp, off_t off)
{
int error;
if (dp->d_reclen > ap->a_uio->uio_resid)
return (ENAMETOOLONG);
error = uiomove(dp, dp->d_reclen, ap->a_uio);
if (error) {
if (ap->a_ncookies != NULL) {
if (ap->a_cookies != NULL)
free(ap->a_cookies, M_TEMP);
ap->a_cookies = NULL;
*ap->a_ncookies = 0;
}
return (error);
}
if (ap->a_ncookies == NULL)
return (0);
KASSERT(ap->a_cookies,
("NULL ap->a_cookies value with non-NULL ap->a_ncookies!"));
*ap->a_cookies = realloc(*ap->a_cookies,
(*ap->a_ncookies + 1) * sizeof(u_long), M_TEMP, M_WAITOK | M_ZERO);
(*ap->a_cookies)[*ap->a_ncookies] = off;
return (0);
}
/*
* Mark for update the access time of the file if the filesystem
* supports VA_MARK_ATIME. This functionality is used by execve
* and mmap, so we want to avoid the synchronous I/O implied by
* directly setting va_atime for the sake of efficiency.
*/
void
vfs_mark_atime(struct vnode *vp, struct thread *td)
{
struct vattr atimeattr;
if ((vp->v_mount->mnt_flag & (MNT_NOATIME | MNT_RDONLY)) == 0) {
VATTR_NULL(&atimeattr);
atimeattr.va_vaflags |= VA_MARK_ATIME;
(void)VOP_SETATTR(vp, &atimeattr, td->td_ucred, td);
}
}
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