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freebsd-dev/sys/kern/vfs_subr.c
Kirk McKusick 192e439ed4 When considering a vnode for reuse in getnewvnode, we call 
vcanrecycle to check a free vnode's availability. If it is
available, vcanrecycle returns an error code of zero and the
vnode in question locked. The getnewvnode routine then used
to call vn_start_write with the V_NOWAIT flag. If the filesystem
was suspended while taking a snapshot, the vn_start_write would
fail but getnewvnode would fail to unlock the vnode, instead
leaving it locked on the freelist. The result would be that the
vnode would be locked forever and would eventually hang the
system with a race to the root when it was attempted to recycle
it. This fix moves the vn_start_write check into vcanrecycle
where it will properly unlock the vnode if it is unavailable
for recycling due to filesystem suspension.

Sponsored by:	DARPA & NAI Labs.
2002-10-11 01:04:14 +00:00

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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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 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
* $FreeBSD$
*/
/*
* External virtual filesystem routines
*/
#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/eventhandler.h>
#include <sys/extattr.h>
#include <sys/fcntl.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/stat.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/vmmeter.h>
#include <sys/vnode.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/uma.h>
static MALLOC_DEFINE(M_NETADDR, "Export Host", "Export host address structure");
static void addalias(struct vnode *vp, dev_t nvp_rdev);
static void insmntque(struct vnode *vp, struct mount *mp);
static void vclean(struct vnode *vp, int flags, struct thread *td);
static void vlruvp(struct vnode *vp);
static int flushbuflist(struct buf *blist, int flags, struct vnode *vp,
int slpflag, int slptimeo, int *errorp);
static int vcanrecycle(struct vnode *vp, struct mount **vnmpp);
/*
* 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;
/*
* Minimum number of free vnodes. If there are fewer than this free vnodes,
* getnewvnode() will return a newly allocated vnode.
*/
static u_long wantfreevnodes = 25;
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, "");
static int nameileafonly;
SYSCTL_INT(_vfs, OID_AUTO, nameileafonly, CTLFLAG_RW, &nameileafonly, 0, "");
#ifdef ENABLE_VFS_IOOPT
/* See NOTES for a description of this setting. */
int vfs_ioopt;
SYSCTL_INT(_vfs, OID_AUTO, ioopt, CTLFLAG_RW, &vfs_ioopt, 0, "");
#endif
/*
* 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;
/*
* For any iteration/modification of dev->si_hlist (linked through
* v_specnext)
*/
static struct mtx spechash_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, vnode);
static struct synclist *syncer_workitem_pending;
/*
* The sync_mtx protects:
* vp->v_synclist
* syncer_delayno
* syncer_workitem_pending
* 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, "");
/*
* 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");
static int minvnodes;
SYSCTL_INT(_kern, OID_AUTO, minvnodes, CTLFLAG_RW,
&minvnodes, 0, "Minimum number of vnodes");
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 *);
/*
* 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)
/* Print lock violations */
int vfs_badlock_print = 1;
/* Panic on violation */
int vfs_badlock_panic = 1;
/* Check for interlock across VOPs */
int vfs_badlock_mutex = 1;
static void
vfs_badlock(char *msg, char *str, struct vnode *vp)
{
if (vfs_badlock_print)
printf("%s: %p %s\n", str, vp, msg);
if (vfs_badlock_panic)
Debugger("Lock violation.\n");
}
void
assert_vi_unlocked(struct vnode *vp, char *str)
{
if (vfs_badlock_mutex && mtx_owned(VI_MTX(vp)))
vfs_badlock("interlock is locked but should not be", str, vp);
}
void
assert_vi_locked(struct vnode *vp, char *str)
{
if (vfs_badlock_mutex && !mtx_owned(VI_MTX(vp)))
vfs_badlock("interlock is not locked but should be", str, vp);
}
void
assert_vop_locked(struct vnode *vp, char *str)
{
if (vp && !IGNORE_LOCK(vp) && !VOP_ISLOCKED(vp, NULL))
vfs_badlock("is not locked but should be", str, vp);
}
void
assert_vop_unlocked(struct vnode *vp, 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, char *str)
{
if (vp && !IGNORE_LOCK(vp) &&
VOP_ISLOCKED(vp, curthread) != LK_EXCLUSIVE)
vfs_badlock("is not exclusive locked but should be", str, vp);
}
void
assert_vop_elocked_other(struct vnode *vp, 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, char *str)
{
if (vp && !IGNORE_LOCK(vp) &&
VOP_ISLOCKED(vp, curthread) != LK_SHARED)
vfs_badlock("is not locked shared but should be", str, vp);
}
void
vop_rename_pre(void *ap)
{
struct vop_rename_args *a = ap;
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.\n");
if (a->a_tvp != a->a_fvp)
ASSERT_VOP_UNLOCKED(a->a_fvp, "vop_rename: tvp locked.\n");
/* Check the target */
if (a->a_tvp)
ASSERT_VOP_LOCKED(a->a_tvp, "vop_rename: tvp not locked.\n");
ASSERT_VOP_LOCKED(a->a_tdvp, "vop_rename: tdvp not locked.\n");
}
void
vop_strategy_pre(void *ap)
{
struct vop_strategy_args *a = ap;
struct buf *bp;
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_panic)
Debugger("Lock violation.\n");
}
}
void
vop_lookup_pre(void *ap)
{
struct vop_lookup_args *a = ap;
struct vnode *dvp;
dvp = a->a_dvp;
ASSERT_VI_UNLOCKED(dvp, "VOP_LOOKUP");
ASSERT_VOP_LOCKED(dvp, "VOP_LOOKUP");
}
void
vop_lookup_post(void *ap, int rc)
{
struct vop_lookup_args *a = ap;
struct componentname *cnp;
struct vnode *dvp;
struct vnode *vp;
int flags;
dvp = a->a_dvp;
cnp = a->a_cnp;
vp = *(a->a_vpp);
flags = cnp->cn_flags;
ASSERT_VI_UNLOCKED(dvp, "VOP_LOOKUP");
/*
* If this is the last path component for this lookup and LOCPARENT
* is set, OR if there is an error the directory has to be locked.
*/
if ((flags & LOCKPARENT) && (flags & ISLASTCN))
ASSERT_VOP_LOCKED(dvp, "VOP_LOOKUP (LOCKPARENT)");
else if (rc != 0)
ASSERT_VOP_LOCKED(dvp, "VOP_LOOKUP (error)");
else if (dvp != vp)
ASSERT_VOP_UNLOCKED(dvp, "VOP_LOOKUP (dvp)");
if (flags & PDIRUNLOCK)
ASSERT_VOP_UNLOCKED(dvp, "VOP_LOOKUP (PDIRUNLOCK)");
}
void
vop_unlock_pre(void *ap)
{
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");
}
void
vop_unlock_post(void *ap, int rc)
{
struct vop_unlock_args *a = ap;
if (a->a_flags & LK_INTERLOCK)
ASSERT_VI_UNLOCKED(a->a_vp, "VOP_UNLOCK");
}
void
vop_lock_pre(void *ap)
{
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");
}
void
vop_lock_post(void *ap, int rc)
{
struct vop_lock_args *a;
a = ap;
ASSERT_VI_UNLOCKED(a->a_vp, "VOP_LOCK");
ASSERT_VOP_LOCKED(a->a_vp, "VOP_LOCK");
}
void
v_addpollinfo(struct vnode *vp)
{
vp->v_pollinfo = uma_zalloc(vnodepoll_zone, M_WAITOK);
mtx_init(&vp->v_pollinfo->vpi_lock, "vnode pollinfo", NULL, MTX_DEF);
}
/*
* Initialize the vnode management data structures.
*/
static void
vntblinit(void *dummy __unused)
{
desiredvnodes = maxproc + cnt.v_page_count / 4;
minvnodes = desiredvnodes / 4;
mtx_init(&mountlist_mtx, "mountlist", NULL, MTX_DEF);
mtx_init(&mntvnode_mtx, "mntvnode", NULL, MTX_DEF);
mtx_init(&mntid_mtx, "mntid", NULL, MTX_DEF);
mtx_init(&spechash_mtx, "spechash", 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;
if (mp->mnt_kern_flag & MNTK_UNMOUNT) {
if (flags & LK_NOWAIT)
return (ENOENT);
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, interlkp, PVFS, "vfs_busy", 0);
return (ENOENT);
}
lkflags = LK_SHARED | LK_NOPAUSE;
if (interlkp)
lkflags |= LK_INTERLOCK;
if (lockmgr(&mp->mnt_lock, lkflags, interlkp, 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;
{
register 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);
}
/*
* 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] = makeudev(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)
register 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, int count)
{
struct vnode *vp;
int done;
int trigger;
int usevnodes;
/*
* 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;
mtx_lock(&mntvnode_mtx);
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);
if (vp->v_type != VNON &&
vp->v_type != VBAD &&
VI_TRYLOCK(vp)) {
if (VMIGHTFREE(vp) && /* critical path opt */
(vp->v_object == NULL ||
vp->v_object->resident_page_count < trigger)) {
mtx_unlock(&mntvnode_mtx);
vgonel(vp, curthread);
done++;
mtx_lock(&mntvnode_mtx);
} else
VI_UNLOCK(vp);
}
--count;
}
mtx_unlock(&mntvnode_mtx);
return done;
}
/*
* 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 s;
int done;
struct proc *p = vnlruproc;
struct thread *td = FIRST_THREAD_IN_PROC(p); /* XXXKSE */
mtx_lock(&Giant);
EVENTHANDLER_REGISTER(shutdown_pre_sync, kproc_shutdown, p,
SHUTDOWN_PRI_FIRST);
s = splbio();
for (;;) {
kthread_suspend_check(p);
mtx_lock(&vnode_free_list_mtx);
if (numvnodes - freevnodes <= desiredvnodes * 9 / 10) {
mtx_unlock(&vnode_free_list_mtx);
vnlruproc_sig = 0;
tsleep(vnlruproc, PVFS, "vlruwt", 0);
continue;
}
mtx_unlock(&vnode_free_list_mtx);
done = 0;
mtx_lock(&mountlist_mtx);
for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
if (vfs_busy(mp, LK_NOWAIT, &mountlist_mtx, td)) {
nmp = TAILQ_NEXT(mp, mnt_list);
continue;
}
done += vlrureclaim(mp, 10);
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);
}
}
splx(s);
}
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.
*/
/*
* Check to see if a free vnode can be recycled. If it can,
* return it locked with the vn lock, but not interlock. Also
* get the vn_start_write lock. Otherwise indicate the error.
*/
static int
vcanrecycle(struct vnode *vp, struct mount **vnmpp)
{
struct thread *td = curthread;
vm_object_t object;
int error;
/* Don't recycle if we can't get the interlock */
if (!VI_TRYLOCK(vp))
return (EWOULDBLOCK);
/* We should be able to immediately acquire this */
/* XXX This looks like it should panic if it fails */
if (vn_lock(vp, LK_INTERLOCK | LK_EXCLUSIVE, td) != 0) {
if (VOP_ISLOCKED(vp, td))
panic("vcanrecycle: locked vnode");
return (EWOULDBLOCK);
}
/*
* Don't recycle if its filesystem is being suspended.
*/
if (vn_start_write(vp, vnmpp, V_NOWAIT) != 0) {
error = EBUSY;
goto done;
}
/*
* Don't recycle if we still have cached pages.
*/
if (VOP_GETVOBJECT(vp, &object) == 0 &&
(object->resident_page_count ||
object->ref_count)) {
error = EBUSY;
goto done;
}
if (LIST_FIRST(&vp->v_cache_src)) {
/*
* note: nameileafonly sysctl is temporary,
* for debugging only, and will eventually be
* removed.
*/
if (nameileafonly > 0) {
/*
* Do not reuse namei-cached directory
* vnodes that have cached
* subdirectories.
*/
if (cache_leaf_test(vp) < 0) {
error = EISDIR;
goto done;
}
} else if (nameileafonly < 0 ||
vmiodirenable == 0) {
/*
* Do not reuse namei-cached directory
* vnodes if nameileafonly is -1 or
* if VMIO backing for directories is
* turned off (otherwise we reuse them
* too quickly).
*/
error = EBUSY;
goto done;
}
}
return (0);
done:
VOP_UNLOCK(vp, 0, td);
return (error);
}
/*
* Return the next vnode from the free list.
*/
int
getnewvnode(tag, mp, vops, vpp)
const char *tag;
struct mount *mp;
vop_t **vops;
struct vnode **vpp;
{
int s;
struct thread *td = curthread; /* XXX */
struct vnode *vp = NULL;
struct mount *vnmp;
s = splbio();
mtx_lock(&vnode_free_list_mtx);
/*
* Try to reuse vnodes if we hit the max. This situation only
* occurs in certain large-memory (2G+) situations. We cannot
* attempt to directly reclaim vnodes due to nasty recursion
* problems.
*/
if (vnlruproc_sig == 0 && numvnodes - freevnodes > desiredvnodes) {
vnlruproc_sig = 1; /* avoid unnecessary wakeups */
wakeup(vnlruproc);
}
/*
* Attempt to reuse a vnode already on the free list, allocating
* a new vnode if we can't find one or if we have not reached a
* good minimum for good LRU performance.
*/
if (freevnodes >= wantfreevnodes && numvnodes >= minvnodes) {
int error;
int count;
for (count = 0; count < freevnodes; count++) {
vp = TAILQ_FIRST(&vnode_free_list);
KASSERT(vp->v_usecount == 0,
("getnewvnode: free vnode isn't"));
TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
/*
* We have to drop the free list mtx to avoid lock
* order reversals with interlock.
*/
mtx_unlock(&vnode_free_list_mtx);
error = vcanrecycle(vp, &vnmp);
mtx_lock(&vnode_free_list_mtx);
if (error != 0)
TAILQ_INSERT_TAIL(&vnode_free_list, vp,
v_freelist);
else
break;
}
}
if (vp) {
freevnodes--;
mtx_unlock(&vnode_free_list_mtx);
cache_purge(vp);
VI_LOCK(vp);
vp->v_iflag |= VI_DOOMED;
vp->v_iflag &= ~VI_FREE;
if (vp->v_type != VBAD) {
VOP_UNLOCK(vp, 0, td);
vgonel(vp, td);
VI_LOCK(vp);
} else {
VOP_UNLOCK(vp, 0, td);
}
vn_finished_write(vnmp);
#ifdef INVARIANTS
{
if (vp->v_data)
panic("cleaned vnode isn't");
if (vp->v_numoutput)
panic("Clean vnode has pending I/O's");
if (vp->v_writecount != 0)
panic("Non-zero write count");
}
#endif
if (vp->v_pollinfo) {
mtx_destroy(&vp->v_pollinfo->vpi_lock);
uma_zfree(vnodepoll_zone, vp->v_pollinfo);
}
vp->v_pollinfo = NULL;
#ifdef MAC
mac_destroy_vnode(vp);
#endif
vp->v_iflag = 0;
vp->v_vflag = 0;
vp->v_lastw = 0;
vp->v_lasta = 0;
vp->v_cstart = 0;
vp->v_clen = 0;
vp->v_socket = 0;
KASSERT(vp->v_cleanblkroot == NULL, ("cleanblkroot not NULL"));
KASSERT(vp->v_dirtyblkroot == NULL, ("dirtyblkroot not NULL"));
} else {
numvnodes++;
mtx_unlock(&vnode_free_list_mtx);
vp = (struct vnode *) uma_zalloc(vnode_zone, M_WAITOK|M_ZERO);
mtx_init(&vp->v_interlock, "vnode interlock", NULL, MTX_DEF);
VI_LOCK(vp);
vp->v_dd = vp;
cache_purge(vp);
LIST_INIT(&vp->v_cache_src);
TAILQ_INIT(&vp->v_cache_dst);
}
TAILQ_INIT(&vp->v_cleanblkhd);
TAILQ_INIT(&vp->v_dirtyblkhd);
vp->v_type = VNON;
vp->v_tag = tag;
vp->v_op = vops;
lockinit(&vp->v_lock, PVFS, "vnlock", VLKTIMEOUT, LK_NOPAUSE);
*vpp = vp;
vp->v_usecount = 1;
vp->v_data = 0;
vp->v_cachedid = -1;
VI_UNLOCK(vp);
#ifdef MAC
mac_init_vnode(vp);
#endif
insmntque(vp, mp);
return (0);
}
/*
* Move a vnode from one mount queue to another.
*/
static void
insmntque(vp, mp)
register struct vnode *vp;
register struct mount *mp;
{
mtx_lock(&mntvnode_mtx);
/*
* Delete from old mount point vnode list, if on one.
*/
if (vp->v_mount != NULL)
TAILQ_REMOVE(&vp->v_mount->mnt_nvnodelist, vp, v_nmntvnodes);
/*
* Insert into list of vnodes for the new mount point, if available.
*/
if ((vp->v_mount = mp) == NULL) {
mtx_unlock(&mntvnode_mtx);
return;
}
TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
mtx_unlock(&mntvnode_mtx);
}
/*
* Update outstanding I/O count and do wakeup if requested.
*/
void
vwakeup(bp)
register struct buf *bp;
{
register struct vnode *vp;
bp->b_flags &= ~B_WRITEINPROG;
if ((vp = bp->b_vp)) {
VI_LOCK(vp);
vp->v_numoutput--;
if (vp->v_numoutput < 0)
panic("vwakeup: neg numoutput");
if ((vp->v_numoutput == 0) && (vp->v_iflag & VI_BWAIT)) {
vp->v_iflag &= ~VI_BWAIT;
wakeup(&vp->v_numoutput);
}
VI_UNLOCK(vp);
}
}
/*
* Flush out and invalidate all buffers associated with a vnode.
* Called with the underlying object locked.
*/
int
vinvalbuf(vp, flags, cred, td, slpflag, slptimeo)
struct vnode *vp;
int flags;
struct ucred *cred;
struct thread *td;
int slpflag, slptimeo;
{
struct buf *blist;
int s, error;
vm_object_t object;
GIANT_REQUIRED;
ASSERT_VOP_LOCKED(vp, "vinvalbuf");
VI_LOCK(vp);
if (flags & V_SAVE) {
s = splbio();
while (vp->v_numoutput) {
vp->v_iflag |= VI_BWAIT;
error = msleep(&vp->v_numoutput, VI_MTX(vp),
slpflag | (PRIBIO + 1), "vinvlbuf", slptimeo);
if (error) {
VI_UNLOCK(vp);
splx(s);
return (error);
}
}
if (!TAILQ_EMPTY(&vp->v_dirtyblkhd)) {
splx(s);
VI_UNLOCK(vp);
if ((error = VOP_FSYNC(vp, cred, MNT_WAIT, td)) != 0)
return (error);
/*
* XXX We could save a lock/unlock if this was only
* enabled under INVARIANTS
*/
VI_LOCK(vp);
s = splbio();
if (vp->v_numoutput > 0 ||
!TAILQ_EMPTY(&vp->v_dirtyblkhd))
panic("vinvalbuf: dirty bufs");
}
splx(s);
}
s = splbio();
/*
* 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.
*/
for (error = 0;;) {
if ((blist = TAILQ_FIRST(&vp->v_cleanblkhd)) != 0 &&
flushbuflist(blist, flags, vp, slpflag, slptimeo, &error)) {
if (error)
break;
continue;
}
if ((blist = TAILQ_FIRST(&vp->v_dirtyblkhd)) != 0 &&
flushbuflist(blist, flags, vp, slpflag, slptimeo, &error)) {
if (error)
break;
continue;
}
break;
}
if (error) {
splx(s);
VI_UNLOCK(vp);
return (error);
}
/*
* 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 {
while (vp->v_numoutput > 0) {
vp->v_iflag |= VI_BWAIT;
msleep(&vp->v_numoutput, VI_MTX(vp), PVM, "vnvlbv", 0);
}
VI_UNLOCK(vp);
if (VOP_GETVOBJECT(vp, &object) == 0) {
while (object->paging_in_progress)
vm_object_pip_sleep(object, "vnvlbx");
}
VI_LOCK(vp);
} while (vp->v_numoutput > 0);
VI_UNLOCK(vp);
splx(s);
/*
* Destroy the copy in the VM cache, too.
*/
if (VOP_GETVOBJECT(vp, &object) == 0) {
vm_object_page_remove(object, 0, 0,
(flags & V_SAVE) ? TRUE : FALSE);
}
#ifdef INVARIANTS
VI_LOCK(vp);
if ((flags & (V_ALT | V_NORMAL)) == 0 &&
(!TAILQ_EMPTY(&vp->v_dirtyblkhd) ||
!TAILQ_EMPTY(&vp->v_cleanblkhd)))
panic("vinvalbuf: flush failed");
VI_UNLOCK(vp);
#endif
return (0);
}
/*
* Flush out buffers on the specified list.
*
*/
static int
flushbuflist(blist, flags, vp, slpflag, slptimeo, errorp)
struct buf *blist;
int flags;
struct vnode *vp;
int slpflag, slptimeo;
int *errorp;
{
struct buf *bp, *nbp;
int found, error;
ASSERT_VI_LOCKED(vp, "flushbuflist");
for (found = 0, bp = blist; bp; bp = nbp) {
nbp = TAILQ_NEXT(bp, b_vnbufs);
VI_UNLOCK(vp);
if (((flags & V_NORMAL) && (bp->b_xflags & BX_ALTDATA)) ||
((flags & V_ALT) && (bp->b_xflags & BX_ALTDATA) == 0)) {
VI_LOCK(vp);
continue;
}
found += 1;
if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
error = BUF_TIMELOCK(bp,
LK_EXCLUSIVE | LK_SLEEPFAIL,
"flushbuf", slpflag, slptimeo);
if (error != ENOLCK)
*errorp = error;
goto done;
}
/*
* 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. Note that vfs_bio_awrite expects
* buffers to reside on a queue, while BUF_WRITE and
* brelse do not.
*/
if (((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) &&
(flags & V_SAVE)) {
if (bp->b_vp == vp) {
if (bp->b_flags & B_CLUSTEROK) {
BUF_UNLOCK(bp);
vfs_bio_awrite(bp);
} else {
bremfree(bp);
bp->b_flags |= B_ASYNC;
BUF_WRITE(bp);
}
} else {
bremfree(bp);
(void) BUF_WRITE(bp);
}
goto done;
}
bremfree(bp);
bp->b_flags |= (B_INVAL | B_NOCACHE | B_RELBUF);
bp->b_flags &= ~B_ASYNC;
brelse(bp);
VI_LOCK(vp);
}
return (found);
done:
VI_LOCK(vp);
return (found);
}
/*
* 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(vp, cred, td, length, blksize)
register struct vnode *vp;
struct ucred *cred;
struct thread *td;
off_t length;
int blksize;
{
register struct buf *bp;
struct buf *nbp;
int s, anyfreed;
int trunclbn;
/*
* Round up to the *next* lbn.
*/
trunclbn = (length + blksize - 1) / blksize;
s = splbio();
ASSERT_VOP_LOCKED(vp, "vtruncbuf");
restart:
VI_LOCK(vp);
anyfreed = 1;
for (;anyfreed;) {
anyfreed = 0;
for (bp = TAILQ_FIRST(&vp->v_cleanblkhd); bp; bp = nbp) {
nbp = TAILQ_NEXT(bp, b_vnbufs);
VI_UNLOCK(vp);
if (bp->b_lblkno >= trunclbn) {
if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL);
goto restart;
} else {
bremfree(bp);
bp->b_flags |= (B_INVAL | B_RELBUF);
bp->b_flags &= ~B_ASYNC;
brelse(bp);
anyfreed = 1;
}
if (nbp &&
(((nbp->b_xflags & BX_VNCLEAN) == 0) ||
(nbp->b_vp != vp) ||
(nbp->b_flags & B_DELWRI))) {
goto restart;
}
}
VI_LOCK(vp);
}
for (bp = TAILQ_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
nbp = TAILQ_NEXT(bp, b_vnbufs);
VI_UNLOCK(vp);
if (bp->b_lblkno >= trunclbn) {
if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL);
goto restart;
} else {
bremfree(bp);
bp->b_flags |= (B_INVAL | B_RELBUF);
bp->b_flags &= ~B_ASYNC;
brelse(bp);
anyfreed = 1;
}
if (nbp &&
(((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:
for (bp = TAILQ_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
nbp = TAILQ_NEXT(bp, b_vnbufs);
VI_UNLOCK(vp);
if ((bp->b_flags & B_DELWRI) && (bp->b_lblkno < 0)) {
if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL);
goto restart;
} else {
bremfree(bp);
if (bp->b_vp == vp) {
bp->b_flags |= B_ASYNC;
} else {
bp->b_flags &= ~B_ASYNC;
}
BUF_WRITE(bp);
}
VI_LOCK(vp);
goto restartsync;
}
VI_LOCK(vp);
}
}
while (vp->v_numoutput > 0) {
vp->v_iflag |= VI_BWAIT;
msleep(&vp->v_numoutput, VI_MTX(vp), PVM, "vbtrunc", 0);
}
VI_UNLOCK(vp);
splx(s);
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 vnode *vp = bp->b_vp;
struct buf *root;
ASSERT_VI_LOCKED(vp, "buf_vlist_remove");
if (bp->b_xflags & BX_VNDIRTY) {
if (bp != vp->v_dirtyblkroot) {
root = buf_splay(bp->b_lblkno, bp->b_xflags, vp->v_dirtyblkroot);
KASSERT(root == bp, ("splay lookup failed during dirty 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;
}
vp->v_dirtyblkroot = root;
TAILQ_REMOVE(&vp->v_dirtyblkhd, bp, b_vnbufs);
} else {
/* KASSERT(bp->b_xflags & BX_VNCLEAN, ("bp wasn't clean")); */
if (bp != vp->v_cleanblkroot) {
root = buf_splay(bp->b_lblkno, bp->b_xflags, vp->v_cleanblkroot);
KASSERT(root == bp, ("splay lookup failed during clean 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;
}
vp->v_cleanblkroot = root;
TAILQ_REMOVE(&vp->v_cleanblkhd, bp, b_vnbufs);
}
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 vnode *vp, b_xflags_t xflags)
{
struct buf *root;
ASSERT_VI_LOCKED(vp, "buf_vlist_add");
bp->b_xflags |= xflags;
if (xflags & BX_VNDIRTY) {
root = buf_splay(bp->b_lblkno, bp->b_xflags, vp->v_dirtyblkroot);
if (root == NULL) {
bp->b_left = NULL;
bp->b_right = NULL;
TAILQ_INSERT_TAIL(&vp->v_dirtyblkhd, bp, b_vnbufs);
} 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_vnbufs);
} else {
bp->b_right = root->b_right;
bp->b_left = root;
root->b_right = NULL;
TAILQ_INSERT_AFTER(&vp->v_dirtyblkhd,
root, bp, b_vnbufs);
}
vp->v_dirtyblkroot = bp;
} else {
/* KASSERT(xflags & BX_VNCLEAN, ("xflags not clean")); */
root = buf_splay(bp->b_lblkno, bp->b_xflags, vp->v_cleanblkroot);
if (root == NULL) {
bp->b_left = NULL;
bp->b_right = NULL;
TAILQ_INSERT_TAIL(&vp->v_cleanblkhd, bp, b_vnbufs);
} 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_vnbufs);
} else {
bp->b_right = root->b_right;
bp->b_left = root;
root->b_right = NULL;
TAILQ_INSERT_AFTER(&vp->v_cleanblkhd,
root, bp, b_vnbufs);
}
vp->v_cleanblkroot = bp;
}
}
#ifndef USE_BUFHASH
/*
* 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.
*/
struct buf *
gbincore(struct vnode *vp, daddr_t lblkno)
{
struct buf *bp;
GIANT_REQUIRED;
ASSERT_VI_LOCKED(vp, "gbincore");
bp = vp->v_cleanblkroot = buf_splay(lblkno, 0, vp->v_cleanblkroot);
if (bp && bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
return(bp);
bp = vp->v_dirtyblkroot = buf_splay(lblkno, 0, vp->v_dirtyblkroot);
if (bp && bp->b_lblkno == lblkno && !(bp->b_xflags & BX_BKGRDMARKER))
return(bp);
return(NULL);
}
#endif
/*
* Associate a buffer with a vnode.
*/
void
bgetvp(vp, bp)
register struct vnode *vp;
register struct buf *bp;
{
int s;
KASSERT(bp->b_vp == NULL, ("bgetvp: not free"));
KASSERT((bp->b_xflags & (BX_VNDIRTY|BX_VNCLEAN)) == 0,
("bgetvp: bp already attached! %p", bp));
VI_LOCK(vp);
vholdl(vp);
bp->b_vp = vp;
bp->b_dev = vn_todev(vp);
/*
* Insert onto list for new vnode.
*/
s = splbio();
buf_vlist_add(bp, vp, BX_VNCLEAN);
splx(s);
VI_UNLOCK(vp);
}
/*
* Disassociate a buffer from a vnode.
*/
void
brelvp(bp)
register struct buf *bp;
{
struct vnode *vp;
int s;
KASSERT(bp->b_vp != NULL, ("brelvp: NULL"));
/*
* Delete from old vnode list, if on one.
*/
vp = bp->b_vp;
s = splbio();
VI_LOCK(vp);
if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN))
buf_vlist_remove(bp);
if ((vp->v_iflag & VI_ONWORKLST) && TAILQ_EMPTY(&vp->v_dirtyblkhd)) {
vp->v_iflag &= ~VI_ONWORKLST;
mtx_lock(&sync_mtx);
LIST_REMOVE(vp, v_synclist);
mtx_unlock(&sync_mtx);
}
vdropl(vp);
VI_UNLOCK(vp);
bp->b_vp = (struct vnode *) 0;
if (bp->b_object)
bp->b_object = NULL;
splx(s);
}
/*
* Add an item to the syncer work queue.
*/
static void
vn_syncer_add_to_worklist(struct vnode *vp, int delay)
{
int s, slot;
s = splbio();
ASSERT_VI_LOCKED(vp, "vn_syncer_add_to_worklist");
mtx_lock(&sync_mtx);
if (vp->v_iflag & VI_ONWORKLST)
LIST_REMOVE(vp, v_synclist);
else
vp->v_iflag |= VI_ONWORKLST;
if (delay > syncer_maxdelay - 2)
delay = syncer_maxdelay - 2;
slot = (syncer_delayno + delay) & syncer_mask;
LIST_INSERT_HEAD(&syncer_workitem_pending[slot], vp, v_synclist);
mtx_unlock(&sync_mtx);
splx(s);
}
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)
/*
* System filesystem synchronizer daemon.
*/
static void
sched_sync(void)
{
struct synclist *slp;
struct vnode *vp;
struct mount *mp;
long starttime;
int s;
struct thread *td = FIRST_THREAD_IN_PROC(updateproc); /* XXXKSE */
mtx_lock(&Giant);
EVENTHANDLER_REGISTER(shutdown_pre_sync, kproc_shutdown, td->td_proc,
SHUTDOWN_PRI_LAST);
for (;;) {
kthread_suspend_check(td->td_proc);
starttime = time_second;
/*
* Push files whose dirty time has expired. Be careful
* of interrupt race on slp queue.
*/
s = splbio();
mtx_lock(&sync_mtx);
slp = &syncer_workitem_pending[syncer_delayno];
syncer_delayno += 1;
if (syncer_delayno == syncer_maxdelay)
syncer_delayno = 0;
splx(s);
while ((vp = LIST_FIRST(slp)) != NULL) {
mtx_unlock(&sync_mtx);
if (VOP_ISLOCKED(vp, NULL) == 0 &&
vn_start_write(vp, &mp, V_NOWAIT) == 0) {
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
(void) VOP_FSYNC(vp, td->td_ucred, MNT_LAZY, td);
VOP_UNLOCK(vp, 0, td);
vn_finished_write(mp);
}
s = splbio();
mtx_lock(&sync_mtx);
if (LIST_FIRST(slp) == vp) {
mtx_unlock(&sync_mtx);
/*
* Note: VFS vnodes can remain on the
* worklist too with no dirty blocks, but
* since sync_fsync() moves it to a different
* slot we are safe.
*/
VI_LOCK(vp);
if (TAILQ_EMPTY(&vp->v_dirtyblkhd) &&
!vn_isdisk(vp, NULL)) {
panic("sched_sync: fsync failed "
"vp %p tag %s", vp, vp->v_tag);
}
/*
* 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(vp, syncdelay);
VI_UNLOCK(vp);
mtx_lock(&sync_mtx);
}
splx(s);
}
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);
/*
* 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 (time_second == 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.
* XXXKSE only one update?
*/
int
speedup_syncer()
{
struct thread *td;
int ret = 0;
td = FIRST_THREAD_IN_PROC(updateproc);
mtx_lock_spin(&sched_lock);
if (td->td_wchan == &lbolt) {
unsleep(td);
TD_CLR_SLEEPING(td);
setrunnable(td);
}
mtx_unlock_spin(&sched_lock);
mtx_lock(&sync_mtx);
if (rushjob < syncdelay / 2) {
rushjob += 1;
stat_rush_requests += 1;
ret = 1;
}
mtx_unlock(&sync_mtx);
return (ret);
}
/*
* Associate a p-buffer with a vnode.
*
* Also sets B_PAGING flag to indicate that vnode is not fully associated
* with the buffer. i.e. the bp has not been linked into the vnode or
* ref-counted.
*/
void
pbgetvp(vp, bp)
register struct vnode *vp;
register struct buf *bp;
{
KASSERT(bp->b_vp == NULL, ("pbgetvp: not free"));
bp->b_vp = vp;
bp->b_flags |= B_PAGING;
bp->b_dev = vn_todev(vp);
}
/*
* Disassociate a p-buffer from a vnode.
*/
void
pbrelvp(bp)
register struct buf *bp;
{
KASSERT(bp->b_vp != NULL, ("pbrelvp: NULL"));
/* XXX REMOVE ME */
VI_LOCK(bp->b_vp);
if (TAILQ_NEXT(bp, b_vnbufs) != NULL) {
panic(
"relpbuf(): b_vp was probably reassignbuf()d %p %x",
bp,
(int)bp->b_flags
);
}
VI_UNLOCK(bp->b_vp);
bp->b_vp = (struct vnode *) 0;
bp->b_flags &= ~B_PAGING;
}
/*
* 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(bp, newvp)
register struct buf *bp;
register struct vnode *newvp;
{
int delay;
int s;
if (newvp == NULL) {
printf("reassignbuf: NULL");
return;
}
++reassignbufcalls;
/*
* 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");
s = splbio();
/*
* Delete from old vnode list, if on one.
*/
VI_LOCK(bp->b_vp);
if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN)) {
buf_vlist_remove(bp);
if (bp->b_vp != newvp) {
vdropl(bp->b_vp);
bp->b_vp = NULL; /* for clarification */
}
}
VI_UNLOCK(bp->b_vp);
/*
* If dirty, put on list of dirty buffers; otherwise insert onto list
* of clean buffers.
*/
VI_LOCK(newvp);
if (bp->b_flags & B_DELWRI) {
if ((newvp->v_iflag & VI_ONWORKLST) == 0) {
switch (newvp->v_type) {
case VDIR:
delay = dirdelay;
break;
case VCHR:
if (newvp->v_rdev->si_mountpoint != NULL) {
delay = metadelay;
break;
}
/* FALLTHROUGH */
default:
delay = filedelay;
}
vn_syncer_add_to_worklist(newvp, delay);
}
buf_vlist_add(bp, newvp, BX_VNDIRTY);
} else {
buf_vlist_add(bp, newvp, BX_VNCLEAN);
if ((newvp->v_iflag & VI_ONWORKLST) &&
TAILQ_EMPTY(&newvp->v_dirtyblkhd)) {
mtx_lock(&sync_mtx);
LIST_REMOVE(newvp, v_synclist);
mtx_unlock(&sync_mtx);
newvp->v_iflag &= ~VI_ONWORKLST;
}
}
if (bp->b_vp != newvp) {
bp->b_vp = newvp;
vholdl(bp->b_vp);
}
VI_UNLOCK(newvp);
splx(s);
}
/*
* Create a vnode for a device.
* Used for mounting the root filesystem.
*/
int
bdevvp(dev, vpp)
dev_t dev;
struct vnode **vpp;
{
register struct vnode *vp;
struct vnode *nvp;
int error;
if (dev == NODEV) {
*vpp = NULLVP;
return (ENXIO);
}
if (vfinddev(dev, VCHR, vpp))
return (0);
error = getnewvnode("none", (struct mount *)0, spec_vnodeop_p, &nvp);
if (error) {
*vpp = NULLVP;
return (error);
}
vp = nvp;
vp->v_type = VCHR;
addalias(vp, dev);
*vpp = vp;
return (0);
}
/*
* Add vnode to the alias list hung off the dev_t.
*
* The reason for this gunk is that multiple vnodes can reference
* the same physical device, so checking vp->v_usecount to see
* how many users there are is inadequate; the v_usecount for
* the vnodes need to be accumulated. vcount() does that.
*/
struct vnode *
addaliasu(nvp, nvp_rdev)
struct vnode *nvp;
udev_t nvp_rdev;
{
struct vnode *ovp;
vop_t **ops;
dev_t dev;
if (nvp->v_type == VBLK)
return (nvp);
if (nvp->v_type != VCHR)
panic("addaliasu on non-special vnode");
dev = udev2dev(nvp_rdev, 0);
/*
* Check to see if we have a bdevvp vnode with no associated
* filesystem. If so, we want to associate the filesystem of
* the new newly instigated vnode with the bdevvp vnode and
* discard the newly created vnode rather than leaving the
* bdevvp vnode lying around with no associated filesystem.
*/
if (vfinddev(dev, nvp->v_type, &ovp) == 0 || ovp->v_data != NULL) {
addalias(nvp, dev);
return (nvp);
}
/*
* Discard unneeded vnode, but save its node specific data.
* Note that if there is a lock, it is carried over in the
* node specific data to the replacement vnode.
*/
vref(ovp);
ovp->v_data = nvp->v_data;
ovp->v_tag = nvp->v_tag;
nvp->v_data = NULL;
lockinit(&ovp->v_lock, PVFS, nvp->v_lock.lk_wmesg,
nvp->v_lock.lk_timo, nvp->v_lock.lk_flags & LK_EXTFLG_MASK);
if (nvp->v_vnlock)
ovp->v_vnlock = &ovp->v_lock;
ops = ovp->v_op;
ovp->v_op = nvp->v_op;
if (VOP_ISLOCKED(nvp, curthread)) {
VOP_UNLOCK(nvp, 0, curthread);
vn_lock(ovp, LK_EXCLUSIVE | LK_RETRY, curthread);
}
nvp->v_op = ops;
insmntque(ovp, nvp->v_mount);
vrele(nvp);
vgone(nvp);
return (ovp);
}
/* This is a local helper function that do the same as addaliasu, but for a
* dev_t instead of an udev_t. */
static void
addalias(nvp, dev)
struct vnode *nvp;
dev_t dev;
{
KASSERT(nvp->v_type == VCHR, ("addalias on non-special vnode"));
nvp->v_rdev = dev;
mtx_lock(&spechash_mtx);
SLIST_INSERT_HEAD(&dev->si_hlist, nvp, v_specnext);
mtx_unlock(&spechash_mtx);
}
/*
* 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)
register struct vnode *vp;
int flags;
struct thread *td;
{
int error;
/*
* If the vnode is in the process of being cleaned out for
* another use, we wait for the cleaning to finish and then
* return failure. Cleaning is determined by checking that
* the VI_XLOCK flag is set.
*/
if ((flags & LK_INTERLOCK) == 0)
VI_LOCK(vp);
if (vp->v_iflag & VI_XLOCK && vp->v_vxproc != curthread) {
vp->v_iflag |= VI_XWANT;
msleep(vp, VI_MTX(vp), PINOD | PDROP, "vget", 0);
return (ENOENT);
}
vp->v_usecount++;
if (VSHOULDBUSY(vp))
vbusy(vp);
if (flags & LK_TYPE_MASK) {
if ((error = vn_lock(vp, flags | LK_INTERLOCK, td)) != 0) {
/*
* 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. We must remove it from the free list
* before sleeping so that multiple processes do
* not try to recycle it.
*/
VI_LOCK(vp);
vp->v_usecount--;
if (VSHOULDFREE(vp))
vfree(vp);
else
vlruvp(vp);
VI_UNLOCK(vp);
}
return (error);
}
VI_UNLOCK(vp);
return (0);
}
/*
* Increase the reference count of a vnode.
*/
void
vref(struct vnode *vp)
{
VI_LOCK(vp);
vp->v_usecount++;
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. */
KASSERT(vp->v_writecount < vp->v_usecount || vp->v_usecount < 1,
("vrele: missed vn_close"));
if (vp->v_usecount > 1) {
vp->v_usecount--;
VI_UNLOCK(vp);
return;
}
if (vp->v_usecount == 1) {
vp->v_usecount--;
/*
* We must call VOP_INACTIVE with the node locked.
* If we are doing a vput, the node is already locked,
* but, in the case of vrele, we must explicitly lock
* the vnode before calling VOP_INACTIVE.
*/
if (vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK, td) == 0)
VOP_INACTIVE(vp, td);
VI_LOCK(vp);
if (VSHOULDFREE(vp))
vfree(vp);
else
vlruvp(vp);
VI_UNLOCK(vp);
} else {
#ifdef DIAGNOSTIC
vprint("vrele: negative ref count", vp);
#endif
VI_UNLOCK(vp);
panic("vrele: negative ref cnt");
}
}
/*
* 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 */
GIANT_REQUIRED;
KASSERT(vp != NULL, ("vput: null vp"));
VI_LOCK(vp);
/* Skip this v_writecount check if we're going to panic below. */
KASSERT(vp->v_writecount < vp->v_usecount || vp->v_usecount < 1,
("vput: missed vn_close"));
if (vp->v_usecount > 1) {
vp->v_usecount--;
VOP_UNLOCK(vp, LK_INTERLOCK, td);
return;
}
if (vp->v_usecount == 1) {
vp->v_usecount--;
/*
* We must call VOP_INACTIVE with the node locked.
* If we are doing a vput, the node is already locked,
* so we just need to release the vnode mutex.
*/
VI_UNLOCK(vp);
VOP_INACTIVE(vp, td);
VI_LOCK(vp);
if (VSHOULDFREE(vp))
vfree(vp);
else
vlruvp(vp);
VI_UNLOCK(vp);
} else {
#ifdef DIAGNOSTIC
vprint("vput: negative ref count", vp);
#endif
panic("vput: negative ref cnt");
}
}
/*
* Somebody doesn't want the vnode recycled.
*/
void
vhold(struct vnode *vp)
{
VI_LOCK(vp);
vholdl(vp);
VI_UNLOCK(vp);
}
void
vholdl(vp)
register struct vnode *vp;
{
int s;
s = splbio();
vp->v_holdcnt++;
if (VSHOULDBUSY(vp))
vbusy(vp);
splx(s);
}
/*
* 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);
VI_UNLOCK(vp);
}
void
vdropl(vp)
register struct vnode *vp;
{
int s;
s = splbio();
if (vp->v_holdcnt <= 0)
panic("vdrop: holdcnt");
vp->v_holdcnt--;
if (VSHOULDFREE(vp))
vfree(vp);
else
vlruvp(vp);
splx(s);
}
/*
* 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()
* 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)
struct mount *mp;
int rootrefs;
int flags;
{
struct thread *td = curthread; /* XXX */
struct vnode *vp, *nvp, *rootvp = NULL;
struct vattr vattr;
int busy = 0, error;
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, &rootvp)) != 0)
return (error);
vput(rootvp);
}
mtx_lock(&mntvnode_mtx);
loop:
for (vp = TAILQ_FIRST(&mp->mnt_nvnodelist); vp; vp = nvp) {
/*
* Make sure this vnode wasn't reclaimed in getnewvnode().
* Start over if it has (it won't be on the list anymore).
*/
if (vp->v_mount != mp)
goto loop;
nvp = TAILQ_NEXT(vp, v_nmntvnodes);
VI_LOCK(vp);
mtx_unlock(&mntvnode_mtx);
vn_lock(vp, LK_INTERLOCK | LK_EXCLUSIVE | LK_RETRY, td);
/*
* Skip over a vnodes marked VV_SYSTEM.
*/
if ((flags & SKIPSYSTEM) && (vp->v_vflag & VV_SYSTEM)) {
VOP_UNLOCK(vp, 0, td);
mtx_lock(&mntvnode_mtx);
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, LK_INTERLOCK, td);
mtx_lock(&mntvnode_mtx);
continue;
}
} else
VI_LOCK(vp);
VOP_UNLOCK(vp, 0, td);
/*
* With v_usecount == 0, all we need to do is clear out the
* vnode data structures and we are done.
*/
if (vp->v_usecount == 0) {
vgonel(vp, td);
mtx_lock(&mntvnode_mtx);
continue;
}
/*
* If FORCECLOSE is set, forcibly close the vnode. For block
* or character devices, revert to an anonymous device. For
* all other files, just kill them.
*/
if (flags & FORCECLOSE) {
if (vp->v_type != VCHR) {
vgonel(vp, td);
} else {
vclean(vp, 0, td);
VI_UNLOCK(vp);
vp->v_op = spec_vnodeop_p;
insmntque(vp, (struct mount *) 0);
}
mtx_lock(&mntvnode_mtx);
continue;
}
#ifdef DIAGNOSTIC
if (busyprt)
vprint("vflush: busy vnode", vp);
#endif
VI_UNLOCK(vp);
mtx_lock(&mntvnode_mtx);
busy++;
}
mtx_unlock(&mntvnode_mtx);
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"));
KASSERT(rootvp->v_usecount >= rootrefs, ("vflush: rootrefs"));
if (busy == 1 && rootvp->v_usecount == rootrefs) {
vgonel(rootvp, td);
busy = 0;
} else
VI_UNLOCK(rootvp);
}
if (busy)
return (EBUSY);
for (; rootrefs > 0; rootrefs--)
vrele(rootvp);
return (0);
}
/*
* This moves a now (likely recyclable) vnode to the end of the
* mountlist. XXX However, it is temporarily disabled until we
* can clean up ffs_sync() and friends, which have loop restart
* conditions which this code causes to operate O(N^2).
*/
static void
vlruvp(struct vnode *vp)
{
#if 0
struct mount *mp;
if ((mp = vp->v_mount) != NULL) {
mtx_lock(&mntvnode_mtx);
TAILQ_REMOVE(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
mtx_unlock(&mntvnode_mtx);
}
#endif
}
/*
* Disassociate the underlying filesystem from a vnode.
*/
static void
vclean(vp, flags, td)
struct vnode *vp;
int flags;
struct thread *td;
{
int active;
ASSERT_VI_LOCKED(vp, "vclean");
/*
* Check to see if the vnode is in use. If so we have to reference it
* before we clean it out so that its count cannot fall to zero and
* generate a race against ourselves to recycle it.
*/
if ((active = vp->v_usecount))
vp->v_usecount++;
/*
* Prevent the vnode from being recycled or brought into use while we
* clean it out.
*/
if (vp->v_iflag & VI_XLOCK)
panic("vclean: deadlock");
vp->v_iflag |= VI_XLOCK;
vp->v_vxproc = curthread;
/*
* Even if the count is zero, the VOP_INACTIVE routine may still
* have the object locked while it cleans it out. The VOP_LOCK
* ensures that the VOP_INACTIVE routine is done with its work.
* For active vnodes, it ensures that no other activity can
* occur while the underlying object is being cleaned out.
*/
VOP_LOCK(vp, LK_DRAIN | LK_INTERLOCK, td);
/*
* Clean out any buffers associated with the vnode.
* If the flush fails, just toss the buffers.
*/
if (flags & DOCLOSE) {
struct buf *bp;
VI_LOCK(vp);
bp = TAILQ_FIRST(&vp->v_dirtyblkhd);
VI_UNLOCK(vp);
if (bp != NULL)
(void) vn_write_suspend_wait(vp, NULL, V_WAIT);
if (vinvalbuf(vp, V_SAVE, NOCRED, td, 0, 0) != 0)
vinvalbuf(vp, 0, NOCRED, td, 0, 0);
}
VOP_DESTROYVOBJECT(vp);
/*
* Any other processes trying to obtain this lock must first
* wait for VXLOCK to clear, then call the new lock operation.
*/
VOP_UNLOCK(vp, 0, td);
/*
* If purging an active vnode, it must be closed and
* deactivated before being reclaimed. Note that the
* VOP_INACTIVE will unlock the vnode.
*/
if (active) {
if (flags & DOCLOSE)
VOP_CLOSE(vp, FNONBLOCK, NOCRED, td);
if (vn_lock(vp, LK_EXCLUSIVE | LK_NOWAIT, td) != 0)
panic("vclean: cannot relock.");
VOP_INACTIVE(vp, td);
}
/*
* Reclaim the vnode.
*/
if (VOP_RECLAIM(vp, td))
panic("vclean: cannot reclaim");
if (active) {
/*
* Inline copy of vrele() since VOP_INACTIVE
* has already been called.
*/
VI_LOCK(vp);
if (--vp->v_usecount <= 0) {
#ifdef DIAGNOSTIC
if (vp->v_usecount < 0 || vp->v_writecount != 0) {
vprint("vclean: bad ref count", vp);
panic("vclean: ref cnt");
}
#endif
vfree(vp);
}
VI_UNLOCK(vp);
}
cache_purge(vp);
vp->v_vnlock = NULL;
lockdestroy(&vp->v_lock);
VI_LOCK(vp);
if (VSHOULDFREE(vp))
vfree(vp);
/*
* Done with purge, notify sleepers of the grim news.
*/
vp->v_op = dead_vnodeop_p;
if (vp->v_pollinfo != NULL)
vn_pollgone(vp);
vp->v_tag = "none";
vp->v_iflag &= ~VI_XLOCK;
vp->v_vxproc = NULL;
if (vp->v_iflag & VI_XWANT) {
vp->v_iflag &= ~VI_XWANT;
wakeup(vp);
}
}
/*
* Eliminate all activity associated with the requested vnode
* and with all vnodes aliased to the requested vnode.
*/
int
vop_revoke(ap)
struct vop_revoke_args /* {
struct vnode *a_vp;
int a_flags;
} */ *ap;
{
struct vnode *vp, *vq;
dev_t dev;
KASSERT((ap->a_flags & REVOKEALL) != 0, ("vop_revoke"));
vp = ap->a_vp;
VI_LOCK(vp);
/*
* If a vgone (or vclean) is already in progress,
* wait until it is done and return.
*/
if (vp->v_iflag & VI_XLOCK) {
vp->v_iflag |= VI_XWANT;
msleep(vp, VI_MTX(vp), PINOD | PDROP,
"vop_revokeall", 0);
return (0);
}
VI_UNLOCK(vp);
dev = vp->v_rdev;
for (;;) {
mtx_lock(&spechash_mtx);
vq = SLIST_FIRST(&dev->si_hlist);
mtx_unlock(&spechash_mtx);
if (!vq)
break;
vgone(vq);
}
return (0);
}
/*
* Recycle an unused vnode to the front of the free list.
* Release the passed interlock if the vnode will be recycled.
*/
int
vrecycle(vp, inter_lkp, td)
struct vnode *vp;
struct mtx *inter_lkp;
struct thread *td;
{
VI_LOCK(vp);
if (vp->v_usecount == 0) {
if (inter_lkp) {
mtx_unlock(inter_lkp);
}
vgonel(vp, td);
return (1);
}
VI_UNLOCK(vp);
return (0);
}
/*
* Eliminate all activity associated with a vnode
* in preparation for reuse.
*/
void
vgone(vp)
register struct vnode *vp;
{
struct thread *td = curthread; /* XXX */
VI_LOCK(vp);
vgonel(vp, td);
}
/*
* vgone, with the vp interlock held.
*/
void
vgonel(vp, td)
struct vnode *vp;
struct thread *td;
{
int s;
/*
* If a vgone (or vclean) is already in progress,
* wait until it is done and return.
*/
ASSERT_VI_LOCKED(vp, "vgonel");
if (vp->v_iflag & VI_XLOCK) {
vp->v_iflag |= VI_XWANT;
msleep(vp, VI_MTX(vp), PINOD | PDROP, "vgone", 0);
return;
}
/*
* Clean out the filesystem specific data.
*/
vclean(vp, DOCLOSE, td);
VI_UNLOCK(vp);
/*
* Delete from old mount point vnode list, if on one.
*/
if (vp->v_mount != NULL)
insmntque(vp, (struct mount *)0);
/*
* If special device, remove it from special device alias list
* if it is on one.
*/
if (vp->v_type == VCHR && vp->v_rdev != NULL && vp->v_rdev != NODEV) {
mtx_lock(&spechash_mtx);
SLIST_REMOVE(&vp->v_rdev->si_hlist, vp, vnode, v_specnext);
freedev(vp->v_rdev);
mtx_unlock(&spechash_mtx);
vp->v_rdev = NULL;
}
/*
* If it is on the freelist and not already at the head,
* move it to the head of the list. The test of the
* VDOOMED flag and the reference count of zero is because
* it will be removed from the free list by getnewvnode,
* but will not have its reference count incremented until
* after calling vgone. If the reference count were
* incremented first, vgone would (incorrectly) try to
* close the previous instance of the underlying object.
*/
VI_LOCK(vp);
if (vp->v_usecount == 0 && !(vp->v_iflag & VI_DOOMED)) {
s = splbio();
mtx_lock(&vnode_free_list_mtx);
if (vp->v_iflag & VI_FREE) {
TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
} else {
vp->v_iflag |= VI_FREE;
freevnodes++;
}
TAILQ_INSERT_HEAD(&vnode_free_list, vp, v_freelist);
mtx_unlock(&vnode_free_list_mtx);
splx(s);
}
vp->v_type = VBAD;
VI_UNLOCK(vp);
}
/*
* Lookup a vnode by device number.
*/
int
vfinddev(dev, type, vpp)
dev_t dev;
enum vtype type;
struct vnode **vpp;
{
struct vnode *vp;
mtx_lock(&spechash_mtx);
SLIST_FOREACH(vp, &dev->si_hlist, v_specnext) {
if (type == vp->v_type) {
*vpp = vp;
mtx_unlock(&spechash_mtx);
return (1);
}
}
mtx_unlock(&spechash_mtx);
return (0);
}
/*
* Calculate the total number of references to a special device.
*/
int
vcount(vp)
struct vnode *vp;
{
struct vnode *vq;
int count;
count = 0;
mtx_lock(&spechash_mtx);
SLIST_FOREACH(vq, &vp->v_rdev->si_hlist, v_specnext) {
if (vq != vp)
VI_LOCK(vq);
count += vq->v_usecount;
if (vq != vp)
VI_UNLOCK(vq);
}
mtx_unlock(&spechash_mtx);
return (count);
}
/*
* Same as above, but using the dev_t as argument
*/
int
count_dev(dev)
dev_t dev;
{
struct vnode *vp;
vp = SLIST_FIRST(&dev->si_hlist);
if (vp == NULL)
return (0);
return(vcount(vp));
}
/*
* Print out a description of a vnode.
*/
static char *typename[] =
{"VNON", "VREG", "VDIR", "VBLK", "VCHR", "VLNK", "VSOCK", "VFIFO", "VBAD"};
void
vprint(label, vp)
char *label;
struct vnode *vp;
{
char buf[96];
if (label != NULL)
printf("%s: %p: ", label, (void *)vp);
else
printf("%p: ", (void *)vp);
printf("tag %s, type %s, usecount %d, writecount %d, refcount %d,",
vp->v_tag, typename[vp->v_type], vp->v_usecount,
vp->v_writecount, vp->v_holdcnt);
buf[0] = '\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_XLOCK)
strcat(buf, "|VI_XLOCK");
if (vp->v_iflag & VI_XWANT)
strcat(buf, "|VI_XWANT");
if (vp->v_iflag & VI_BWAIT)
strcat(buf, "|VI_BWAIT");
if (vp->v_iflag & VI_DOOMED)
strcat(buf, "|VI_DOOMED");
if (vp->v_iflag & VI_FREE)
strcat(buf, "|VI_FREE");
if (vp->v_vflag & VV_OBJBUF)
strcat(buf, "|VV_OBJBUF");
if (buf[0] != '\0')
printf(" flags (%s),", &buf[1]);
lockmgr_printinfo(&vp->v_lock);
printf("\n");
if (vp->v_data != NULL) {
printf("\t");
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 thread *td = curthread; /* XXX */
struct mount *mp, *nmp;
struct vnode *vp;
printf("Locked vnodes\n");
mtx_lock(&mountlist_mtx);
for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
if (vfs_busy(mp, LK_NOWAIT, &mountlist_mtx, td)) {
nmp = TAILQ_NEXT(mp, mnt_list);
continue;
}
mtx_lock(&mntvnode_mtx);
TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
if (VOP_ISLOCKED(vp, NULL))
vprint((char *)0, vp);
}
mtx_unlock(&mntvnode_mtx);
mtx_lock(&mountlist_mtx);
nmp = TAILQ_NEXT(mp, mnt_list);
vfs_unbusy(mp, td);
}
mtx_unlock(&mountlist_mtx);
}
#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;
}
static int
sysctl_vfs_conflist(SYSCTL_HANDLER_ARGS)
{
struct vfsconf *vfsp;
struct xvfsconf *xvfsp;
int cnt, error, i;
cnt = 0;
for (vfsp = vfsconf; vfsp != NULL; vfsp = vfsp->vfc_next)
cnt++;
xvfsp = malloc(sizeof(struct xvfsconf) * cnt, M_TEMP, M_WAITOK);
/*
* Handle the race that we will have here when struct vfsconf
* will be locked down by using both cnt and checking vfc_next
* against NULL to determine the end of the loop. The race will
* happen because we will have to unlock before calling malloc().
* We are protected by Giant for now.
*/
i = 0;
for (vfsp = vfsconf; vfsp != NULL && i < cnt; vfsp = vfsp->vfc_next) {
vfsconf2x(vfsp, xvfsp + i);
i++;
}
error = SYSCTL_OUT(req, xvfsp, sizeof(struct xvfsconf) * i);
free(xvfsp, M_TEMP);
return (error);
}
SYSCTL_PROC(_vfs, OID_AUTO, conflist, CTLFLAG_RD, NULL, 0, sysctl_vfs_conflist,
"S,xvfsconf", "List of all configured filesystems");
/*
* Top level filesystem related information gathering.
*/
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 */
for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
if (vfsp->vfc_typenum == name[2])
break;
if (vfsp == NULL)
return (EOPNOTSUPP);
vfsconf2x(vfsp, &xvfsp);
return (SYSCTL_OUT(req, &xvfsp, sizeof(xvfsp)));
}
return (EOPNOTSUPP);
}
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;
for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next) {
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 */
#define KINFO_VNODESLOP 10
/*
* 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));
sysctl_wire_old_buffer(req, 0);
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;
mtx_lock(&mntvnode_mtx);
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;
#define XV_COPY(field) xvn[n].xv_##field = vp->v_##field
XV_COPY(usecount);
XV_COPY(writecount);
XV_COPY(holdcnt);
XV_COPY(id);
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:
xvn[n].xv_dev = vp->v_cachedfs;
xvn[n].xv_ino = vp->v_cachedid;
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;
}
mtx_unlock(&mntvnode_mtx);
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", "");
/*
* Check to see if a filesystem is mounted on a block device.
*/
int
vfs_mountedon(vp)
struct vnode *vp;
{
if (vp->v_rdev->si_mountpoint != NULL)
return (EBUSY);
return (0);
}
/*
* 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;
if (curthread != NULL)
td = curthread;
else
td = FIRST_THREAD_IN_PROC(initproc); /* XXX XXX proc0? */
/*
* 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);
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;
GIANT_REQUIRED;
tries = 5;
mtx_lock(&mntvnode_mtx);
loop:
for (vp = TAILQ_FIRST(&mp->mnt_nvnodelist); vp != NULL; vp = nvp) {
if (vp->v_mount != mp) {
if (--tries > 0)
goto loop;
break;
}
nvp = TAILQ_NEXT(vp, v_nmntvnodes);
VI_LOCK(vp);
if (vp->v_iflag & VI_XLOCK) { /* XXX: what if MNT_WAIT? */
VI_UNLOCK(vp);
continue;
}
if ((vp->v_iflag & VI_OBJDIRTY) &&
(flags == MNT_WAIT || VOP_ISLOCKED(vp, NULL) == 0)) {
mtx_unlock(&mntvnode_mtx);
if (!vget(vp,
LK_EXCLUSIVE | LK_RETRY | LK_INTERLOCK,
curthread)) {
if (vp->v_vflag & VV_NOSYNC) { /* unlinked */
vput(vp);
mtx_lock(&mntvnode_mtx);
continue;
}
if (VOP_GETVOBJECT(vp, &obj) == 0) {
vm_object_page_clean(obj, 0, 0,
flags == MNT_WAIT ?
OBJPC_SYNC : OBJPC_NOSYNC);
}
vput(vp);
}
mtx_lock(&mntvnode_mtx);
if (TAILQ_NEXT(vp, v_nmntvnodes) != nvp) {
if (--tries > 0)
goto loop;
break;
}
} else
VI_UNLOCK(vp);
}
mtx_unlock(&mntvnode_mtx);
}
/*
* Create the VM object needed for VMIO and mmap support. This
* is done for all VREG files in the system. Some filesystems might
* afford the additional metadata buffering capability of the
* VMIO code by making the device node be VMIO mode also.
*
* vp must be locked when vfs_object_create is called.
*/
int
vfs_object_create(vp, td, cred)
struct vnode *vp;
struct thread *td;
struct ucred *cred;
{
GIANT_REQUIRED;
return (VOP_CREATEVOBJECT(vp, cred, td));
}
/*
* Mark a vnode as free, putting it up for recycling.
*/
void
vfree(vp)
struct vnode *vp;
{
int s;
ASSERT_VI_LOCKED(vp, "vfree");
s = splbio();
mtx_lock(&vnode_free_list_mtx);
KASSERT((vp->v_iflag & VI_FREE) == 0, ("vnode already free"));
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++;
mtx_unlock(&vnode_free_list_mtx);
vp->v_iflag &= ~VI_AGE;
vp->v_iflag |= VI_FREE;
splx(s);
}
/*
* Opposite of vfree() - mark a vnode as in use.
*/
void
vbusy(vp)
struct vnode *vp;
{
int s;
s = splbio();
ASSERT_VI_LOCKED(vp, "vbusy");
KASSERT((vp->v_iflag & VI_FREE) != 0, ("vnode not free"));
mtx_lock(&vnode_free_list_mtx);
TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
freevnodes--;
mtx_unlock(&vnode_free_list_mtx);
vp->v_iflag &= ~(VI_FREE|VI_AGE);
splx(s);
}
/*
* 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;
}
/*
* Note the occurrence of an event. If the VN_POLLEVENT macro is used,
* it is possible for us to miss an event due to race conditions, but
* that condition is expected to be rare, so for the moment it is the
* preferred interface.
*/
void
vn_pollevent(vp, events)
struct vnode *vp;
short events;
{
if (vp->v_pollinfo == NULL)
v_addpollinfo(vp);
mtx_lock(&vp->v_pollinfo->vpi_lock);
if (vp->v_pollinfo->vpi_events & events) {
/*
* We clear vpi_events so that we don't
* call selwakeup() twice if two events are
* posted before the polling process(es) is
* awakened. This also ensures that we take at
* most one selwakeup() if the polling process
* is no longer interested. However, it does
* mean that only one event can be noticed at
* a time. (Perhaps we should only clear those
* event bits which we note?) XXX
*/
vp->v_pollinfo->vpi_events = 0; /* &= ~events ??? */
vp->v_pollinfo->vpi_revents |= events;
selwakeup(&vp->v_pollinfo->vpi_selinfo);
}
mtx_unlock(&vp->v_pollinfo->vpi_lock);
}
/*
* Wake up anyone polling on vp because it is being revoked.
* This depends on dead_poll() returning POLLHUP for correct
* behavior.
*/
void
vn_pollgone(vp)
struct vnode *vp;
{
mtx_lock(&vp->v_pollinfo->vpi_lock);
VN_KNOTE(vp, NOTE_REVOKE);
if (vp->v_pollinfo->vpi_events) {
vp->v_pollinfo->vpi_events = 0;
selwakeup(&vp->v_pollinfo->vpi_selinfo);
}
mtx_unlock(&vp->v_pollinfo->vpi_lock);
}
/*
* 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 int sync_print(struct vop_print_args *);
static vop_t **sync_vnodeop_p;
static struct vnodeopv_entry_desc sync_vnodeop_entries[] = {
{ &vop_default_desc, (vop_t *) vop_eopnotsupp },
{ &vop_close_desc, (vop_t *) sync_close }, /* close */
{ &vop_fsync_desc, (vop_t *) sync_fsync }, /* fsync */
{ &vop_inactive_desc, (vop_t *) sync_inactive }, /* inactive */
{ &vop_reclaim_desc, (vop_t *) sync_reclaim }, /* reclaim */
{ &vop_lock_desc, (vop_t *) vop_stdlock }, /* lock */
{ &vop_unlock_desc, (vop_t *) vop_stdunlock }, /* unlock */
{ &vop_print_desc, (vop_t *) sync_print }, /* print */
{ &vop_islocked_desc, (vop_t *) vop_stdislocked }, /* islocked */
{ NULL, NULL }
};
static struct vnodeopv_desc sync_vnodeop_opv_desc =
{ &sync_vnodeop_p, sync_vnodeop_entries };
VNODEOP_SET(sync_vnodeop_opv_desc);
/*
* 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("vfs", mp, sync_vnodeop_p, &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, syncdelay > 0 ? next % syncdelay : 0);
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 asyncflag;
/*
* 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.
*/
VI_LOCK(syncvp);
vn_syncer_add_to_worklist(syncvp, syncdelay);
VI_UNLOCK(syncvp);
/*
* 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);
VFS_SYNC(mp, MNT_LAZY, ap->a_cred, td);
if (asyncflag)
mp->mnt_flag |= MNT_ASYNC;
vn_finished_write(mp);
vfs_unbusy(mp, td);
return (0);
}
/*
* The syncer vnode is no referenced.
*/
static int
sync_inactive(ap)
struct vop_inactive_args /* {
struct vnode *a_vp;
struct thread *a_td;
} */ *ap;
{
VOP_UNLOCK(ap->a_vp, 0, ap->a_td);
vgone(ap->a_vp);
return (0);
}
/*
* The syncer vnode is no longer needed and is being decommissioned.
*
* Modifications to the worklist must be protected at splbio().
*/
static int
sync_reclaim(ap)
struct vop_reclaim_args /* {
struct vnode *a_vp;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
int s;
s = splbio();
vp->v_mount->mnt_syncer = NULL;
VI_LOCK(vp);
if (vp->v_iflag & VI_ONWORKLST) {
mtx_lock(&sync_mtx);
LIST_REMOVE(vp, v_synclist);
mtx_unlock(&sync_mtx);
vp->v_iflag &= ~VI_ONWORKLST;
}
VI_UNLOCK(vp);
splx(s);
return (0);
}
/*
* Print out a syncer vnode.
*/
static int
sync_print(ap)
struct vop_print_args /* {
struct vnode *a_vp;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
printf("syncer vnode");
if (vp->v_vnlock != NULL)
lockmgr_printinfo(vp->v_vnlock);
printf("\n");
return (0);
}
/*
* extract the dev_t from a VCHR
*/
dev_t
vn_todev(vp)
struct vnode *vp;
{
if (vp->v_type != VCHR)
return (NODEV);
return (vp->v_rdev);
}
/*
* Check if vnode represents a disk device
*/
int
vn_isdisk(vp, errp)
struct vnode *vp;
int *errp;
{
struct cdevsw *cdevsw;
if (vp->v_type != VCHR) {
if (errp != NULL)
*errp = ENOTBLK;
return (0);
}
if (vp->v_rdev == NULL) {
if (errp != NULL)
*errp = ENXIO;
return (0);
}
cdevsw = devsw(vp->v_rdev);
if (cdevsw == NULL) {
if (errp != NULL)
*errp = ENXIO;
return (0);
}
if (!(cdevsw->d_flags & D_DISK)) {
if (errp != NULL)
*errp = ENOTBLK;
return (0);
}
if (errp != NULL)
*errp = 0;
return (1);
}
/*
* Free data allocated by namei(); see namei(9) for details.
*/
void
NDFREE(ndp, flags)
struct nameidata *ndp;
const uint flags;
{
if (!(flags & NDF_NO_FREE_PNBUF) &&
(ndp->ni_cnd.cn_flags & HASBUF)) {
uma_zfree(namei_zone, ndp->ni_cnd.cn_pnbuf);
ndp->ni_cnd.cn_flags &= ~HASBUF;
}
if (!(flags & NDF_NO_DVP_UNLOCK) &&
(ndp->ni_cnd.cn_flags & LOCKPARENT) &&
ndp->ni_dvp != ndp->ni_vp)
VOP_UNLOCK(ndp->ni_dvp, 0, ndp->ni_cnd.cn_thread);
if (!(flags & NDF_NO_DVP_RELE) &&
(ndp->ni_cnd.cn_flags & (LOCKPARENT|WANTPARENT))) {
vrele(ndp->ni_dvp);
ndp->ni_dvp = NULL;
}
if (!(flags & NDF_NO_VP_UNLOCK) &&
(ndp->ni_cnd.cn_flags & LOCKLEAF) && ndp->ni_vp)
VOP_UNLOCK(ndp->ni_vp, 0, ndp->ni_cnd.cn_thread);
if (!(flags & NDF_NO_VP_RELE) &&
ndp->ni_vp) {
vrele(ndp->ni_vp);
ndp->ni_vp = NULL;
}
if (!(flags & NDF_NO_STARTDIR_RELE) &&
(ndp->ni_cnd.cn_flags & SAVESTART)) {
vrele(ndp->ni_startdir);
ndp->ni_startdir = NULL;
}
}
/*
* 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, PRISON_ROOT)) {
/* 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, PRISON_ROOT))
cap_granted |= VEXEC;
} else {
if ((acc_mode & VEXEC) && ((dac_granted & VEXEC) == 0) &&
!cap_check(cred, NULL, CAP_DAC_EXECUTE, PRISON_ROOT))
cap_granted |= VEXEC;
}
if ((acc_mode & VREAD) && ((dac_granted & VREAD) == 0) &&
!cap_check(cred, NULL, CAP_DAC_READ_SEARCH, PRISON_ROOT))
cap_granted |= VREAD;
if ((acc_mode & VWRITE) && ((dac_granted & VWRITE) == 0) &&
!cap_check(cred, NULL, CAP_DAC_WRITE, PRISON_ROOT))
cap_granted |= (VWRITE | VAPPEND);
if ((acc_mode & VADMIN) && ((dac_granted & VADMIN) == 0) &&
!cap_check(cred, NULL, CAP_FOWNER, PRISON_ROOT))
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);
}
}
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