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NetBSD/sys/kern/vfs_vnops.c

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/* $NetBSD: vfs_vnops.c,v 1.80 2004/05/31 09:02:51 yamt Exp $ */
/*
* Copyright (c) 1982, 1986, 1989, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)vfs_vnops.c 8.14 (Berkeley) 6/15/95
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: vfs_vnops.c,v 1.80 2004/05/31 09:02:51 yamt Exp $");
#include "fs_union.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/buf.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/ioctl.h>
#include <sys/tty.h>
#include <sys/poll.h>
#include <miscfs/specfs/specdev.h>
#include <uvm/uvm_extern.h>
#ifdef UNION
#include <fs/union/union.h>
#endif
#if defined(LKM) || defined(UNION)
int (*vn_union_readdir_hook) (struct vnode **, struct file *, struct proc *);
#endif
#ifdef VERIFIED_EXEC
#include <sys/verified_exec.h>
extern LIST_HEAD(veriexec_devhead, veriexec_dev_list) veriexec_dev_head;
extern struct veriexec_devhead veriexec_file_dev_head;
#endif
static int vn_read(struct file *fp, off_t *offset, struct uio *uio,
struct ucred *cred, int flags);
static int vn_write(struct file *fp, off_t *offset, struct uio *uio,
struct ucred *cred, int flags);
static int vn_closefile(struct file *fp, struct proc *p);
static int vn_poll(struct file *fp, int events, struct proc *p);
static int vn_fcntl(struct file *fp, u_int com, void *data, struct proc *p);
static int vn_statfile(struct file *fp, struct stat *sb, struct proc *p);
static int vn_ioctl(struct file *fp, u_long com, void *data, struct proc *p);
struct fileops vnops = {
vn_read, vn_write, vn_ioctl, vn_fcntl, vn_poll,
vn_statfile, vn_closefile, vn_kqfilter
};
/*
* Common code for vnode open operations.
* Check permissions, and call the VOP_OPEN or VOP_CREATE routine.
*/
int
vn_open(ndp, fmode, cmode)
struct nameidata *ndp;
int fmode, cmode;
{
struct vnode *vp;
struct mount *mp;
struct proc *p = ndp->ni_cnd.cn_proc;
struct ucred *cred = p->p_ucred;
struct vattr va;
int error;
#ifdef VERIFIED_EXEC
char got_dev;
struct veriexec_inode_list *veriexec_node;
char fingerprint[MAXFINGERPRINTLEN];
#endif
restart:
if (fmode & O_CREAT) {
ndp->ni_cnd.cn_nameiop = CREATE;
ndp->ni_cnd.cn_flags = LOCKPARENT | LOCKLEAF;
if ((fmode & O_EXCL) == 0 &&
((fmode & O_NOFOLLOW) == 0))
ndp->ni_cnd.cn_flags |= FOLLOW;
if ((error = namei(ndp)) != 0)
return (error);
if (ndp->ni_vp == NULL) {
VATTR_NULL(&va);
va.va_type = VREG;
va.va_mode = cmode;
if (fmode & O_EXCL)
va.va_vaflags |= VA_EXCLUSIVE;
if (vn_start_write(ndp->ni_dvp, &mp, V_NOWAIT) != 0) {
VOP_ABORTOP(ndp->ni_dvp, &ndp->ni_cnd);
vput(ndp->ni_dvp);
if ((error = vn_start_write(NULL, &mp,
V_WAIT | V_SLEEPONLY | V_PCATCH)) != 0)
return (error);
goto restart;
}
VOP_LEASE(ndp->ni_dvp, p, cred, LEASE_WRITE);
error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp,
&ndp->ni_cnd, &va);
vn_finished_write(mp, 0);
if (error)
return (error);
fmode &= ~O_TRUNC;
vp = ndp->ni_vp;
} else {
VOP_ABORTOP(ndp->ni_dvp, &ndp->ni_cnd);
if (ndp->ni_dvp == ndp->ni_vp)
vrele(ndp->ni_dvp);
else
vput(ndp->ni_dvp);
ndp->ni_dvp = NULL;
vp = ndp->ni_vp;
if (fmode & O_EXCL) {
error = EEXIST;
goto bad;
}
fmode &= ~O_CREAT;
}
} else {
ndp->ni_cnd.cn_nameiop = LOOKUP;
ndp->ni_cnd.cn_flags = LOCKLEAF;
if ((fmode & O_NOFOLLOW) == 0)
ndp->ni_cnd.cn_flags |= FOLLOW;
if ((error = namei(ndp)) != 0)
return (error);
vp = ndp->ni_vp;
}
if (vp->v_type == VSOCK) {
error = EOPNOTSUPP;
goto bad;
}
if (ndp->ni_vp->v_type == VLNK) {
error = EFTYPE;
goto bad;
}
#ifdef VERIFIED_EXEC
veriexec_node = NULL;
if ((error = VOP_GETATTR(vp, &va, cred, p)) != 0)
goto bad;
#endif
if ((fmode & O_CREAT) == 0) {
#ifdef VERIFIED_EXEC
/*
* Look for the file on the fingerprint lists iff
* it has not been seen before.
*/
if ((vp->fp_status == FINGERPRINT_INVALID) ||
(vp->fp_status == FINGERPRINT_NODEV)) {
/* check the file list for the finger print */
veriexec_node = get_veriexec_inode(&veriexec_file_dev_head,
va.va_fsid,
va.va_fileid,
&got_dev);
if (veriexec_node == NULL) {
/* failing that, check the exec list */
veriexec_node = get_veriexec_inode(
&veriexec_dev_head, va.va_fsid,
va.va_fileid, &got_dev);
}
if ((veriexec_node == NULL) && (got_dev == 1))
vp->fp_status = FINGERPRINT_NOENTRY;
if (veriexec_node != NULL) {
if ((error = evaluate_fingerprint(vp,
veriexec_node, p, va.va_size,
fingerprint)) != 0)
goto bad;
if (fingerprintcmp(veriexec_node,
fingerprint) == 0) {
/* fingerprint ok */
vp->fp_status = FINGERPRINT_VALID;
#ifdef VERIFIED_EXEC_DEBUG
printf(
"file fingerprint matches for dev %lu, file %lu\n",
va.va_fsid, va.va_fileid);
#endif
} else {
vp->fp_status = FINGERPRINT_NOMATCH;
}
}
}
#endif
if (fmode & FREAD) {
if ((error = VOP_ACCESS(vp, VREAD, cred, p)) != 0)
goto bad;
#ifdef VERIFIED_EXEC
/* file is on finger print list */
if (vp->fp_status == FINGERPRINT_NOMATCH) {
/* fingerprint bad */
printf(
"file fingerprint does not match on dev %lu, file %lu\n",
va.va_fsid, va.va_fileid);
if (securelevel > 2) {
error = EPERM;
goto bad;
}
}
#endif
}
if (fmode & (FWRITE | O_TRUNC)) {
if (vp->v_type == VDIR) {
error = EISDIR;
goto bad;
}
if ((error = vn_writechk(vp)) != 0 ||
(error = VOP_ACCESS(vp, VWRITE, cred, p)) != 0)
goto bad;
#ifdef VERIFIED_EXEC
/*
* If file has a fingerprint then
* deny the write request, otherwise
* invalidate the status so we don't
* keep checking for the file having
* a fingerprint.
*/
if (vp->fp_status == FINGERPRINT_VALID) {
printf(
"writing to fingerprinted file for dev %lu, file %lu\n",
va.va_fsid, va.va_fileid);
if (securelevel > 2) {
error = EPERM;
goto bad;
} else {
vp->fp_status = FINGERPRINT_INVALID;
}
}
#endif
}
}
if (fmode & O_TRUNC) {
VOP_UNLOCK(vp, 0); /* XXX */
if ((error = vn_start_write(vp, &mp, V_WAIT | V_PCATCH)) != 0) {
vput(vp);
return (error);
}
VOP_LEASE(vp, p, cred, LEASE_WRITE);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); /* XXX */
VATTR_NULL(&va);
va.va_size = 0;
error = VOP_SETATTR(vp, &va, cred, p);
vn_finished_write(mp, 0);
if (error != 0)
goto bad;
}
if ((error = VOP_OPEN(vp, fmode, cred, p)) != 0)
goto bad;
if (vp->v_type == VREG &&
uvn_attach(vp, fmode & FWRITE ? VM_PROT_WRITE : 0) == NULL) {
error = EIO;
goto bad;
}
if (fmode & FWRITE)
vp->v_writecount++;
return (0);
bad:
vput(vp);
return (error);
}
/*
* Check for write permissions on the specified vnode.
* Prototype text segments cannot be written.
*/
int
vn_writechk(vp)
struct vnode *vp;
{
/*
* If the vnode is in use as a process's text,
* we can't allow writing.
*/
if (vp->v_flag & VTEXT)
return (ETXTBSY);
return (0);
}
/*
* Mark a vnode as having executable mappings.
*/
void
vn_markexec(vp)
struct vnode *vp;
{
if ((vp->v_flag & VEXECMAP) == 0) {
uvmexp.filepages -= vp->v_uobj.uo_npages;
uvmexp.execpages += vp->v_uobj.uo_npages;
}
vp->v_flag |= VEXECMAP;
}
/*
* Mark a vnode as being the text of a process.
* Fail if the vnode is currently writable.
*/
int
vn_marktext(vp)
struct vnode *vp;
{
if (vp->v_writecount != 0) {
KASSERT((vp->v_flag & VTEXT) == 0);
return (ETXTBSY);
}
vp->v_flag |= VTEXT;
vn_markexec(vp);
return (0);
}
/*
* Vnode close call
*
* Note: takes an unlocked vnode, while VOP_CLOSE takes a locked node.
*/
int
vn_close(vp, flags, cred, p)
struct vnode *vp;
int flags;
struct ucred *cred;
struct proc *p;
{
int error;
if (flags & FWRITE)
vp->v_writecount--;
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
error = VOP_CLOSE(vp, flags, cred, p);
vput(vp);
return (error);
}
/*
* Package up an I/O request on a vnode into a uio and do it.
*/
int
vn_rdwr(rw, vp, base, len, offset, segflg, ioflg, cred, aresid, p)
enum uio_rw rw;
struct vnode *vp;
caddr_t base;
int len;
off_t offset;
enum uio_seg segflg;
int ioflg;
struct ucred *cred;
size_t *aresid;
struct proc *p;
{
struct uio auio;
struct iovec aiov;
struct mount *mp;
int error;
if ((ioflg & IO_NODELOCKED) == 0) {
if (rw == UIO_READ) {
vn_lock(vp, LK_SHARED | LK_RETRY);
} else /* UIO_WRITE */ {
if (vp->v_type != VCHR &&
(error = vn_start_write(vp, &mp, V_WAIT | V_PCATCH))
!= 0)
return (error);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
}
}
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
aiov.iov_base = base;
aiov.iov_len = len;
auio.uio_resid = len;
auio.uio_offset = offset;
auio.uio_segflg = segflg;
auio.uio_rw = rw;
auio.uio_procp = p;
if (rw == UIO_READ) {
error = VOP_READ(vp, &auio, ioflg, cred);
} else {
error = VOP_WRITE(vp, &auio, ioflg, cred);
}
if (aresid)
*aresid = auio.uio_resid;
else
if (auio.uio_resid && error == 0)
error = EIO;
if ((ioflg & IO_NODELOCKED) == 0) {
if (rw == UIO_WRITE)
vn_finished_write(mp, 0);
VOP_UNLOCK(vp, 0);
}
return (error);
}
int
vn_readdir(fp, buf, segflg, count, done, p, cookies, ncookies)
struct file *fp;
char *buf;
int segflg, *done, *ncookies;
u_int count;
struct proc *p;
off_t **cookies;
{
struct vnode *vp = (struct vnode *)fp->f_data;
struct iovec aiov;
struct uio auio;
int error, eofflag;
unionread:
if (vp->v_type != VDIR)
return (EINVAL);
aiov.iov_base = buf;
aiov.iov_len = count;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_rw = UIO_READ;
auio.uio_segflg = segflg;
auio.uio_procp = p;
auio.uio_resid = count;
vn_lock(vp, LK_SHARED | LK_RETRY);
auio.uio_offset = fp->f_offset;
error = VOP_READDIR(vp, &auio, fp->f_cred, &eofflag, cookies,
ncookies);
fp->f_offset = auio.uio_offset;
VOP_UNLOCK(vp, 0);
if (error)
return (error);
#if defined(UNION) || defined(LKM)
if (count == auio.uio_resid && vn_union_readdir_hook) {
struct vnode *ovp = vp;
error = (*vn_union_readdir_hook)(&vp, fp, p);
if (error)
return (error);
if (vp != ovp)
goto unionread;
}
#endif /* UNION || LKM */
if (count == auio.uio_resid && (vp->v_flag & VROOT) &&
(vp->v_mount->mnt_flag & MNT_UNION)) {
struct vnode *tvp = vp;
vp = vp->v_mount->mnt_vnodecovered;
VREF(vp);
fp->f_data = vp;
fp->f_offset = 0;
vrele(tvp);
goto unionread;
}
*done = count - auio.uio_resid;
return error;
}
/*
* File table vnode read routine.
*/
static int
vn_read(fp, offset, uio, cred, flags)
struct file *fp;
off_t *offset;
struct uio *uio;
struct ucred *cred;
int flags;
{
struct vnode *vp = (struct vnode *)fp->f_data;
int count, error, ioflag = 0;
VOP_LEASE(vp, uio->uio_procp, cred, LEASE_READ);
if (fp->f_flag & FNONBLOCK)
ioflag |= IO_NDELAY;
if ((fp->f_flag & (FFSYNC | FRSYNC)) == (FFSYNC | FRSYNC))
ioflag |= IO_SYNC;
if (fp->f_flag & FALTIO)
ioflag |= IO_ALTSEMANTICS;
vn_lock(vp, LK_SHARED | LK_RETRY);
uio->uio_offset = *offset;
count = uio->uio_resid;
error = VOP_READ(vp, uio, ioflag, cred);
if (flags & FOF_UPDATE_OFFSET)
*offset += count - uio->uio_resid;
VOP_UNLOCK(vp, 0);
return (error);
}
/*
* File table vnode write routine.
*/
static int
vn_write(fp, offset, uio, cred, flags)
struct file *fp;
off_t *offset;
struct uio *uio;
struct ucred *cred;
int flags;
{
struct vnode *vp = (struct vnode *)fp->f_data;
struct mount *mp;
int count, error, ioflag = IO_UNIT;
if (vp->v_type == VREG && (fp->f_flag & O_APPEND))
ioflag |= IO_APPEND;
if (fp->f_flag & FNONBLOCK)
ioflag |= IO_NDELAY;
if (fp->f_flag & FFSYNC ||
(vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS)))
ioflag |= IO_SYNC;
else if (fp->f_flag & FDSYNC)
ioflag |= IO_DSYNC;
if (fp->f_flag & FALTIO)
ioflag |= IO_ALTSEMANTICS;
mp = NULL;
if (vp->v_type != VCHR &&
(error = vn_start_write(vp, &mp, V_WAIT | V_PCATCH)) != 0)
return (error);
VOP_LEASE(vp, uio->uio_procp, cred, LEASE_WRITE);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
uio->uio_offset = *offset;
count = uio->uio_resid;
error = VOP_WRITE(vp, uio, ioflag, cred);
if (flags & FOF_UPDATE_OFFSET) {
if (ioflag & IO_APPEND)
*offset = uio->uio_offset;
else
*offset += count - uio->uio_resid;
}
VOP_UNLOCK(vp, 0);
vn_finished_write(mp, 0);
return (error);
}
/*
* File table vnode stat routine.
*/
static int
vn_statfile(fp, sb, p)
struct file *fp;
struct stat *sb;
struct proc *p;
{
struct vnode *vp = (struct vnode *)fp->f_data;
return vn_stat(vp, sb, p);
}
int
vn_stat(vp, sb, p)
struct vnode *vp;
struct stat *sb;
struct proc *p;
{
struct vattr va;
int error;
mode_t mode;
error = VOP_GETATTR(vp, &va, p->p_ucred, p);
if (error)
return (error);
/*
* Copy from vattr table
*/
sb->st_dev = va.va_fsid;
sb->st_ino = va.va_fileid;
mode = va.va_mode;
switch (vp->v_type) {
case VREG:
mode |= S_IFREG;
break;
case VDIR:
mode |= S_IFDIR;
break;
case VBLK:
mode |= S_IFBLK;
break;
case VCHR:
mode |= S_IFCHR;
break;
case VLNK:
mode |= S_IFLNK;
break;
case VSOCK:
mode |= S_IFSOCK;
break;
case VFIFO:
mode |= S_IFIFO;
break;
default:
return (EBADF);
};
sb->st_mode = mode;
sb->st_nlink = va.va_nlink;
sb->st_uid = va.va_uid;
sb->st_gid = va.va_gid;
sb->st_rdev = va.va_rdev;
sb->st_size = va.va_size;
sb->st_atimespec = va.va_atime;
sb->st_mtimespec = va.va_mtime;
sb->st_ctimespec = va.va_ctime;
sb->st_birthtimespec = va.va_birthtime;
sb->st_blksize = va.va_blocksize;
sb->st_flags = va.va_flags;
sb->st_gen = 0;
sb->st_blocks = va.va_bytes / S_BLKSIZE;
return (0);
}
/*
* File table vnode fcntl routine.
*/
static int
vn_fcntl(fp, com, data, p)
struct file *fp;
u_int com;
void *data;
struct proc *p;
{
struct vnode *vp = ((struct vnode *)fp->f_data);
int error;
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
error = VOP_FCNTL(vp, com, data, fp->f_flag, p->p_ucred, p);
VOP_UNLOCK(vp, 0);
return (error);
}
/*
* File table vnode ioctl routine.
*/
static int
vn_ioctl(fp, com, data, p)
struct file *fp;
u_long com;
void *data;
struct proc *p;
{
struct vnode *vp = ((struct vnode *)fp->f_data);
struct vattr vattr;
int error;
switch (vp->v_type) {
case VREG:
case VDIR:
if (com == FIONREAD) {
error = VOP_GETATTR(vp, &vattr, p->p_ucred, p);
if (error)
return (error);
*(int *)data = vattr.va_size - fp->f_offset;
return (0);
}
if (com == FIOGETBMAP) {
daddr_t *block;
if (*(daddr_t *)data < 0)
return (EINVAL);
block = (daddr_t *)data;
return (VOP_BMAP(vp, *block, NULL, block, NULL));
}
if (com == OFIOGETBMAP) {
daddr_t ibn, obn;
if (*(int32_t *)data < 0)
return (EINVAL);
ibn = (daddr_t)*(int32_t *)data;
error = VOP_BMAP(vp, ibn, NULL, &obn, NULL);
*(int32_t *)data = (int32_t)obn;
return error;
}
if (com == FIONBIO || com == FIOASYNC) /* XXX */
return (0); /* XXX */
/* fall into ... */
case VFIFO:
case VCHR:
case VBLK:
error = VOP_IOCTL(vp, com, data, fp->f_flag, p->p_ucred, p);
if (error == 0 && com == TIOCSCTTY) {
if (p->p_session->s_ttyvp)
vrele(p->p_session->s_ttyvp);
p->p_session->s_ttyvp = vp;
VREF(vp);
}
return (error);
default:
return (EPASSTHROUGH);
}
}
/*
* File table vnode poll routine.
*/
static int
vn_poll(fp, events, p)
struct file *fp;
int events;
struct proc *p;
{
return (VOP_POLL(((struct vnode *)fp->f_data), events, p));
}
/*
* File table vnode kqfilter routine.
*/
int
vn_kqfilter(fp, kn)
struct file *fp;
struct knote *kn;
{
return (VOP_KQFILTER((struct vnode *)fp->f_data, kn));
}
/*
* Check that the vnode is still valid, and if so
* acquire requested lock.
*/
int
vn_lock(vp, flags)
struct vnode *vp;
int flags;
{
int error;
KASSERT(vp->v_usecount > 0 || (flags & LK_INTERLOCK) != 0
|| (vp->v_flag & VONWORKLST) != 0);
do {
if ((flags & LK_INTERLOCK) == 0)
simple_lock(&vp->v_interlock);
if (vp->v_flag & VXLOCK) {
if (flags & LK_NOWAIT) {
simple_unlock(&vp->v_interlock);
return EBUSY;
}
vp->v_flag |= VXWANT;
ltsleep(vp, PINOD | PNORELOCK,
"vn_lock", 0, &vp->v_interlock);
error = ENOENT;
} else {
error = VOP_LOCK(vp,
(flags & ~LK_RETRY) | LK_INTERLOCK);
if (error == 0 || error == EDEADLK || error == EBUSY)
return (error);
}
flags &= ~LK_INTERLOCK;
} while (flags & LK_RETRY);
return (error);
}
/*
* File table vnode close routine.
*/
static int
vn_closefile(fp, p)
struct file *fp;
struct proc *p;
{
return (vn_close(((struct vnode *)fp->f_data), fp->f_flag,
fp->f_cred, p));
}
/*
* Enable LK_CANRECURSE on lock. Return prior status.
*/
u_int
vn_setrecurse(vp)
struct vnode *vp;
{
struct lock *lkp = &vp->v_lock;
u_int retval = lkp->lk_flags & LK_CANRECURSE;
lkp->lk_flags |= LK_CANRECURSE;
return retval;
}
/*
* Called when done with locksetrecurse.
*/
void
vn_restorerecurse(vp, flags)
struct vnode *vp;
u_int flags;
{
struct lock *lkp = &vp->v_lock;
lkp->lk_flags &= ~LK_CANRECURSE;
lkp->lk_flags |= flags;
}
int
vn_cow_establish(struct vnode *vp,
int (*func)(void *, struct buf *), void *cookie)
{
int s;
struct spec_cow_entry *e;
MALLOC(e, struct spec_cow_entry *, sizeof(struct spec_cow_entry),
M_DEVBUF, M_WAITOK);
e->ce_func = func;
e->ce_cookie = cookie;
SPEC_COW_LOCK(vp->v_specinfo, s);
vp->v_spec_cow_req++;
while (vp->v_spec_cow_count > 0)
ltsleep(&vp->v_spec_cow_req, PRIBIO, "cowlist", 0,
&vp->v_spec_cow_slock);
SLIST_INSERT_HEAD(&vp->v_spec_cow_head, e, ce_list);
vp->v_spec_cow_req--;
if (vp->v_spec_cow_req == 0)
wakeup(&vp->v_spec_cow_req);
SPEC_COW_UNLOCK(vp->v_specinfo, s);
return 0;
}
int
vn_cow_disestablish(struct vnode *vp,
int (*func)(void *, struct buf *), void *cookie)
{
int s;
struct spec_cow_entry *e;
SPEC_COW_LOCK(vp->v_specinfo, s);
vp->v_spec_cow_req++;
while (vp->v_spec_cow_count > 0)
ltsleep(&vp->v_spec_cow_req, PRIBIO, "cowlist", 0,
&vp->v_spec_cow_slock);
SLIST_FOREACH(e, &vp->v_spec_cow_head, ce_list)
if (e->ce_func == func && e->ce_cookie == cookie) {
SLIST_REMOVE(&vp->v_spec_cow_head, e,
spec_cow_entry, ce_list);
FREE(e, M_DEVBUF);
break;
}
vp->v_spec_cow_req--;
if (vp->v_spec_cow_req == 0)
wakeup(&vp->v_spec_cow_req);
SPEC_COW_UNLOCK(vp->v_specinfo, s);
return e ? 0 : EINVAL;
}
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