freebsd-dev/sys/compat/linux/linux_stats.c
Mateusz Guzik c8b3463dd0 vfs: reimplement deferred inactive to use a dedicated flag (VI_DEFINACT)
The previous behavior of leaving VI_OWEINACT vnodes on the active list without
a hold count is eliminated. Hold count is kept and inactive processing gets
explicitly deferred by setting the VI_DEFINACT flag. The syncer is then
responsible for vdrop.

Reviewed by:	kib (previous version)
Tested by:	pho (in a larger patch, previous version)
Differential Revision:	https://reviews.freebsd.org/D23036
2020-01-07 15:56:24 +00:00

680 lines
18 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 1994-1995 Søren Schmidt
* All rights reserved.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_compat.h"
#include <sys/param.h>
#include <sys/capsicum.h>
#include <sys/dirent.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/stat.h>
#include <sys/syscallsubr.h>
#include <sys/systm.h>
#include <sys/tty.h>
#include <sys/vnode.h>
#include <sys/conf.h>
#include <sys/fcntl.h>
#ifdef COMPAT_LINUX32
#include <machine/../linux32/linux.h>
#include <machine/../linux32/linux32_proto.h>
#else
#include <machine/../linux/linux.h>
#include <machine/../linux/linux_proto.h>
#endif
#include <compat/linux/linux_util.h>
#include <compat/linux/linux_file.h>
static void
translate_vnhook_major_minor(struct vnode *vp, struct stat *sb)
{
int major, minor;
if (vn_isdisk(vp, NULL)) {
sb->st_mode &= ~S_IFMT;
sb->st_mode |= S_IFBLK;
}
if (vp->v_type == VCHR && vp->v_rdev != NULL &&
linux_driver_get_major_minor(devtoname(vp->v_rdev),
&major, &minor) == 0) {
sb->st_rdev = (major << 8 | minor);
}
}
static int
linux_kern_statat(struct thread *td, int flag, int fd, char *path,
enum uio_seg pathseg, struct stat *sbp)
{
return (kern_statat(td, flag, fd, path, pathseg, sbp,
translate_vnhook_major_minor));
}
#ifdef LINUX_LEGACY_SYSCALLS
static int
linux_kern_stat(struct thread *td, char *path, enum uio_seg pathseg,
struct stat *sbp)
{
return (linux_kern_statat(td, 0, AT_FDCWD, path, pathseg, sbp));
}
static int
linux_kern_lstat(struct thread *td, char *path, enum uio_seg pathseg,
struct stat *sbp)
{
return (linux_kern_statat(td, AT_SYMLINK_NOFOLLOW, AT_FDCWD, path,
pathseg, sbp));
}
#endif
static void
translate_fd_major_minor(struct thread *td, int fd, struct stat *buf)
{
struct file *fp;
struct vnode *vp;
int major, minor;
/*
* No capability rights required here.
*/
if ((!S_ISCHR(buf->st_mode) && !S_ISBLK(buf->st_mode)) ||
fget(td, fd, &cap_no_rights, &fp) != 0)
return;
vp = fp->f_vnode;
if (vp != NULL && vn_isdisk(vp, NULL)) {
buf->st_mode &= ~S_IFMT;
buf->st_mode |= S_IFBLK;
}
if (vp != NULL && vp->v_rdev != NULL &&
linux_driver_get_major_minor(devtoname(vp->v_rdev),
&major, &minor) == 0) {
buf->st_rdev = (major << 8 | minor);
} else if (fp->f_type == DTYPE_PTS) {
struct tty *tp = fp->f_data;
/* Convert the numbers for the slave device. */
if (linux_driver_get_major_minor(devtoname(tp->t_dev),
&major, &minor) == 0) {
buf->st_rdev = (major << 8 | minor);
}
}
fdrop(fp, td);
}
/*
* l_dev_t has the same encoding as dev_t in the latter's low 16 bits, so
* truncation of a dev_t to 16 bits gives the same result as unpacking
* using major() and minor() and repacking in the l_dev_t format. This
* detail is hidden in dev_to_ldev(). Overflow in conversions of dev_t's
* are not checked for, as for other fields.
*
* dev_to_ldev() is only used for translating st_dev. When we convert
* st_rdev for copying it out, it isn't really a dev_t, but has already
* been translated to an l_dev_t in a nontrivial way. Translating it
* again would be illogical but would have no effect since the low 16
* bits have the same encoding.
*
* The nontrivial translation for st_rdev renumbers some devices, but not
* ones that can be mounted on, so it is consistent with the translation
* for st_dev except when the renumbering or truncation causes conflicts.
*/
#define dev_to_ldev(d) ((uint16_t)(d))
static int
newstat_copyout(struct stat *buf, void *ubuf)
{
struct l_newstat tbuf;
bzero(&tbuf, sizeof(tbuf));
tbuf.st_dev = dev_to_ldev(buf->st_dev);
tbuf.st_ino = buf->st_ino;
tbuf.st_mode = buf->st_mode;
tbuf.st_nlink = buf->st_nlink;
tbuf.st_uid = buf->st_uid;
tbuf.st_gid = buf->st_gid;
tbuf.st_rdev = buf->st_rdev;
tbuf.st_size = buf->st_size;
tbuf.st_atim.tv_sec = buf->st_atim.tv_sec;
tbuf.st_atim.tv_nsec = buf->st_atim.tv_nsec;
tbuf.st_mtim.tv_sec = buf->st_mtim.tv_sec;
tbuf.st_mtim.tv_nsec = buf->st_mtim.tv_nsec;
tbuf.st_ctim.tv_sec = buf->st_ctim.tv_sec;
tbuf.st_ctim.tv_nsec = buf->st_ctim.tv_nsec;
tbuf.st_blksize = buf->st_blksize;
tbuf.st_blocks = buf->st_blocks;
return (copyout(&tbuf, ubuf, sizeof(tbuf)));
}
#ifdef LINUX_LEGACY_SYSCALLS
int
linux_newstat(struct thread *td, struct linux_newstat_args *args)
{
struct stat buf;
char *path;
int error;
LCONVPATHEXIST(td, args->path, &path);
error = linux_kern_stat(td, path, UIO_SYSSPACE, &buf);
LFREEPATH(path);
if (error)
return (error);
return (newstat_copyout(&buf, args->buf));
}
int
linux_newlstat(struct thread *td, struct linux_newlstat_args *args)
{
struct stat sb;
char *path;
int error;
LCONVPATHEXIST(td, args->path, &path);
error = linux_kern_lstat(td, path, UIO_SYSSPACE, &sb);
LFREEPATH(path);
if (error)
return (error);
return (newstat_copyout(&sb, args->buf));
}
#endif
int
linux_newfstat(struct thread *td, struct linux_newfstat_args *args)
{
struct stat buf;
int error;
error = kern_fstat(td, args->fd, &buf);
translate_fd_major_minor(td, args->fd, &buf);
if (!error)
error = newstat_copyout(&buf, args->buf);
return (error);
}
#if defined(__i386__) || (defined(__amd64__) && defined(COMPAT_LINUX32))
static int
stat_copyout(struct stat *buf, void *ubuf)
{
struct l_stat lbuf;
bzero(&lbuf, sizeof(lbuf));
lbuf.st_dev = dev_to_ldev(buf->st_dev);
lbuf.st_ino = buf->st_ino;
lbuf.st_mode = buf->st_mode;
lbuf.st_nlink = buf->st_nlink;
lbuf.st_uid = buf->st_uid;
lbuf.st_gid = buf->st_gid;
lbuf.st_rdev = buf->st_rdev;
lbuf.st_size = MIN(buf->st_size, INT32_MAX);
lbuf.st_atim.tv_sec = buf->st_atim.tv_sec;
lbuf.st_atim.tv_nsec = buf->st_atim.tv_nsec;
lbuf.st_mtim.tv_sec = buf->st_mtim.tv_sec;
lbuf.st_mtim.tv_nsec = buf->st_mtim.tv_nsec;
lbuf.st_ctim.tv_sec = buf->st_ctim.tv_sec;
lbuf.st_ctim.tv_nsec = buf->st_ctim.tv_nsec;
lbuf.st_blksize = buf->st_blksize;
lbuf.st_blocks = buf->st_blocks;
lbuf.st_flags = buf->st_flags;
lbuf.st_gen = buf->st_gen;
return (copyout(&lbuf, ubuf, sizeof(lbuf)));
}
int
linux_stat(struct thread *td, struct linux_stat_args *args)
{
struct stat buf;
char *path;
int error;
LCONVPATHEXIST(td, args->path, &path);
error = linux_kern_stat(td, path, UIO_SYSSPACE, &buf);
if (error) {
LFREEPATH(path);
return (error);
}
LFREEPATH(path);
return (stat_copyout(&buf, args->up));
}
int
linux_lstat(struct thread *td, struct linux_lstat_args *args)
{
struct stat buf;
char *path;
int error;
LCONVPATHEXIST(td, args->path, &path);
error = linux_kern_lstat(td, path, UIO_SYSSPACE, &buf);
if (error) {
LFREEPATH(path);
return (error);
}
LFREEPATH(path);
return (stat_copyout(&buf, args->up));
}
#endif /* __i386__ || (__amd64__ && COMPAT_LINUX32) */
struct l_statfs {
l_long f_type;
l_long f_bsize;
l_long f_blocks;
l_long f_bfree;
l_long f_bavail;
l_long f_files;
l_long f_ffree;
l_fsid_t f_fsid;
l_long f_namelen;
l_long f_frsize;
l_long f_flags;
l_long f_spare[4];
};
#define LINUX_CODA_SUPER_MAGIC 0x73757245L
#define LINUX_EXT2_SUPER_MAGIC 0xEF53L
#define LINUX_HPFS_SUPER_MAGIC 0xf995e849L
#define LINUX_ISOFS_SUPER_MAGIC 0x9660L
#define LINUX_MSDOS_SUPER_MAGIC 0x4d44L
#define LINUX_NCP_SUPER_MAGIC 0x564cL
#define LINUX_NFS_SUPER_MAGIC 0x6969L
#define LINUX_NTFS_SUPER_MAGIC 0x5346544EL
#define LINUX_PROC_SUPER_MAGIC 0x9fa0L
#define LINUX_UFS_SUPER_MAGIC 0x00011954L /* XXX - UFS_MAGIC in Linux */
#define LINUX_ZFS_SUPER_MAGIC 0x2FC12FC1
#define LINUX_DEVFS_SUPER_MAGIC 0x1373L
#define LINUX_SHMFS_MAGIC 0x01021994
static long
bsd_to_linux_ftype(const char *fstypename)
{
int i;
static struct {const char *bsd_name; long linux_type;} b2l_tbl[] = {
{"ufs", LINUX_UFS_SUPER_MAGIC},
{"zfs", LINUX_ZFS_SUPER_MAGIC},
{"cd9660", LINUX_ISOFS_SUPER_MAGIC},
{"nfs", LINUX_NFS_SUPER_MAGIC},
{"ext2fs", LINUX_EXT2_SUPER_MAGIC},
{"procfs", LINUX_PROC_SUPER_MAGIC},
{"msdosfs", LINUX_MSDOS_SUPER_MAGIC},
{"ntfs", LINUX_NTFS_SUPER_MAGIC},
{"nwfs", LINUX_NCP_SUPER_MAGIC},
{"hpfs", LINUX_HPFS_SUPER_MAGIC},
{"coda", LINUX_CODA_SUPER_MAGIC},
{"devfs", LINUX_DEVFS_SUPER_MAGIC},
{"tmpfs", LINUX_SHMFS_MAGIC},
{NULL, 0L}};
for (i = 0; b2l_tbl[i].bsd_name != NULL; i++)
if (strcmp(b2l_tbl[i].bsd_name, fstypename) == 0)
return (b2l_tbl[i].linux_type);
return (0L);
}
static int
bsd_to_linux_statfs(struct statfs *bsd_statfs, struct l_statfs *linux_statfs)
{
#if defined(__i386__) || (defined(__amd64__) && defined(COMPAT_LINUX32))
uint64_t tmp;
#define LINUX_HIBITS 0xffffffff00000000ULL
tmp = bsd_statfs->f_blocks | bsd_statfs->f_bfree | bsd_statfs->f_files |
bsd_statfs->f_bsize;
if ((bsd_statfs->f_bavail != -1 && (bsd_statfs->f_bavail & LINUX_HIBITS)) ||
(bsd_statfs->f_ffree != -1 && (bsd_statfs->f_ffree & LINUX_HIBITS)) ||
(tmp & LINUX_HIBITS))
return (EOVERFLOW);
#undef LINUX_HIBITS
#endif
linux_statfs->f_type = bsd_to_linux_ftype(bsd_statfs->f_fstypename);
linux_statfs->f_bsize = bsd_statfs->f_bsize;
linux_statfs->f_blocks = bsd_statfs->f_blocks;
linux_statfs->f_bfree = bsd_statfs->f_bfree;
linux_statfs->f_bavail = bsd_statfs->f_bavail;
linux_statfs->f_ffree = bsd_statfs->f_ffree;
linux_statfs->f_files = bsd_statfs->f_files;
linux_statfs->f_fsid.val[0] = bsd_statfs->f_fsid.val[0];
linux_statfs->f_fsid.val[1] = bsd_statfs->f_fsid.val[1];
linux_statfs->f_namelen = MAXNAMLEN;
linux_statfs->f_frsize = bsd_statfs->f_bsize;
linux_statfs->f_flags = 0;
memset(linux_statfs->f_spare, 0, sizeof(linux_statfs->f_spare));
return (0);
}
int
linux_statfs(struct thread *td, struct linux_statfs_args *args)
{
struct l_statfs linux_statfs;
struct statfs *bsd_statfs;
char *path;
int error;
LCONVPATHEXIST(td, args->path, &path);
bsd_statfs = malloc(sizeof(struct statfs), M_STATFS, M_WAITOK);
error = kern_statfs(td, path, UIO_SYSSPACE, bsd_statfs);
LFREEPATH(path);
if (error == 0)
error = bsd_to_linux_statfs(bsd_statfs, &linux_statfs);
free(bsd_statfs, M_STATFS);
if (error != 0)
return (error);
return (copyout(&linux_statfs, args->buf, sizeof(linux_statfs)));
}
#if defined(__i386__) || (defined(__amd64__) && defined(COMPAT_LINUX32))
static void
bsd_to_linux_statfs64(struct statfs *bsd_statfs, struct l_statfs64 *linux_statfs)
{
linux_statfs->f_type = bsd_to_linux_ftype(bsd_statfs->f_fstypename);
linux_statfs->f_bsize = bsd_statfs->f_bsize;
linux_statfs->f_blocks = bsd_statfs->f_blocks;
linux_statfs->f_bfree = bsd_statfs->f_bfree;
linux_statfs->f_bavail = bsd_statfs->f_bavail;
linux_statfs->f_ffree = bsd_statfs->f_ffree;
linux_statfs->f_files = bsd_statfs->f_files;
linux_statfs->f_fsid.val[0] = bsd_statfs->f_fsid.val[0];
linux_statfs->f_fsid.val[1] = bsd_statfs->f_fsid.val[1];
linux_statfs->f_namelen = MAXNAMLEN;
linux_statfs->f_frsize = bsd_statfs->f_bsize;
linux_statfs->f_flags = 0;
memset(linux_statfs->f_spare, 0, sizeof(linux_statfs->f_spare));
}
int
linux_statfs64(struct thread *td, struct linux_statfs64_args *args)
{
struct l_statfs64 linux_statfs;
struct statfs *bsd_statfs;
char *path;
int error;
if (args->bufsize != sizeof(struct l_statfs64))
return (EINVAL);
LCONVPATHEXIST(td, args->path, &path);
bsd_statfs = malloc(sizeof(struct statfs), M_STATFS, M_WAITOK);
error = kern_statfs(td, path, UIO_SYSSPACE, bsd_statfs);
LFREEPATH(path);
if (error == 0)
bsd_to_linux_statfs64(bsd_statfs, &linux_statfs);
free(bsd_statfs, M_STATFS);
if (error != 0)
return (error);
return (copyout(&linux_statfs, args->buf, sizeof(linux_statfs)));
}
int
linux_fstatfs64(struct thread *td, struct linux_fstatfs64_args *args)
{
struct l_statfs64 linux_statfs;
struct statfs *bsd_statfs;
int error;
if (args->bufsize != sizeof(struct l_statfs64))
return (EINVAL);
bsd_statfs = malloc(sizeof(struct statfs), M_STATFS, M_WAITOK);
error = kern_fstatfs(td, args->fd, bsd_statfs);
if (error == 0)
bsd_to_linux_statfs64(bsd_statfs, &linux_statfs);
free(bsd_statfs, M_STATFS);
if (error != 0)
return (error);
return (copyout(&linux_statfs, args->buf, sizeof(linux_statfs)));
}
#endif /* __i386__ || (__amd64__ && COMPAT_LINUX32) */
int
linux_fstatfs(struct thread *td, struct linux_fstatfs_args *args)
{
struct l_statfs linux_statfs;
struct statfs *bsd_statfs;
int error;
bsd_statfs = malloc(sizeof(struct statfs), M_STATFS, M_WAITOK);
error = kern_fstatfs(td, args->fd, bsd_statfs);
if (error == 0)
error = bsd_to_linux_statfs(bsd_statfs, &linux_statfs);
free(bsd_statfs, M_STATFS);
if (error != 0)
return (error);
return (copyout(&linux_statfs, args->buf, sizeof(linux_statfs)));
}
struct l_ustat
{
l_daddr_t f_tfree;
l_ino_t f_tinode;
char f_fname[6];
char f_fpack[6];
};
#ifdef LINUX_LEGACY_SYSCALLS
int
linux_ustat(struct thread *td, struct linux_ustat_args *args)
{
return (EOPNOTSUPP);
}
#endif
#if defined(__i386__) || (defined(__amd64__) && defined(COMPAT_LINUX32))
static int
stat64_copyout(struct stat *buf, void *ubuf)
{
struct l_stat64 lbuf;
bzero(&lbuf, sizeof(lbuf));
lbuf.st_dev = dev_to_ldev(buf->st_dev);
lbuf.st_ino = buf->st_ino;
lbuf.st_mode = buf->st_mode;
lbuf.st_nlink = buf->st_nlink;
lbuf.st_uid = buf->st_uid;
lbuf.st_gid = buf->st_gid;
lbuf.st_rdev = buf->st_rdev;
lbuf.st_size = buf->st_size;
lbuf.st_atim.tv_sec = buf->st_atim.tv_sec;
lbuf.st_atim.tv_nsec = buf->st_atim.tv_nsec;
lbuf.st_mtim.tv_sec = buf->st_mtim.tv_sec;
lbuf.st_mtim.tv_nsec = buf->st_mtim.tv_nsec;
lbuf.st_ctim.tv_sec = buf->st_ctim.tv_sec;
lbuf.st_ctim.tv_nsec = buf->st_ctim.tv_nsec;
lbuf.st_blksize = buf->st_blksize;
lbuf.st_blocks = buf->st_blocks;
/*
* The __st_ino field makes all the difference. In the Linux kernel
* it is conditionally compiled based on STAT64_HAS_BROKEN_ST_INO,
* but without the assignment to __st_ino the runtime linker refuses
* to mmap(2) any shared libraries. I guess it's broken alright :-)
*/
lbuf.__st_ino = buf->st_ino;
return (copyout(&lbuf, ubuf, sizeof(lbuf)));
}
int
linux_stat64(struct thread *td, struct linux_stat64_args *args)
{
struct stat buf;
char *filename;
int error;
LCONVPATHEXIST(td, args->filename, &filename);
error = linux_kern_stat(td, filename, UIO_SYSSPACE, &buf);
LFREEPATH(filename);
if (error)
return (error);
return (stat64_copyout(&buf, args->statbuf));
}
int
linux_lstat64(struct thread *td, struct linux_lstat64_args *args)
{
struct stat sb;
char *filename;
int error;
LCONVPATHEXIST(td, args->filename, &filename);
error = linux_kern_lstat(td, filename, UIO_SYSSPACE, &sb);
LFREEPATH(filename);
if (error)
return (error);
return (stat64_copyout(&sb, args->statbuf));
}
int
linux_fstat64(struct thread *td, struct linux_fstat64_args *args)
{
struct stat buf;
int error;
error = kern_fstat(td, args->fd, &buf);
translate_fd_major_minor(td, args->fd, &buf);
if (!error)
error = stat64_copyout(&buf, args->statbuf);
return (error);
}
int
linux_fstatat64(struct thread *td, struct linux_fstatat64_args *args)
{
char *path;
int error, dfd, flag;
struct stat buf;
if (args->flag & ~LINUX_AT_SYMLINK_NOFOLLOW)
return (EINVAL);
flag = (args->flag & LINUX_AT_SYMLINK_NOFOLLOW) ?
AT_SYMLINK_NOFOLLOW : 0;
dfd = (args->dfd == LINUX_AT_FDCWD) ? AT_FDCWD : args->dfd;
LCONVPATHEXIST_AT(td, args->pathname, &path, dfd);
error = linux_kern_statat(td, flag, dfd, path, UIO_SYSSPACE, &buf);
if (!error)
error = stat64_copyout(&buf, args->statbuf);
LFREEPATH(path);
return (error);
}
#else /* __amd64__ && !COMPAT_LINUX32 */
int
linux_newfstatat(struct thread *td, struct linux_newfstatat_args *args)
{
char *path;
int error, dfd, flag;
struct stat buf;
if (args->flag & ~LINUX_AT_SYMLINK_NOFOLLOW)
return (EINVAL);
flag = (args->flag & LINUX_AT_SYMLINK_NOFOLLOW) ?
AT_SYMLINK_NOFOLLOW : 0;
dfd = (args->dfd == LINUX_AT_FDCWD) ? AT_FDCWD : args->dfd;
LCONVPATHEXIST_AT(td, args->pathname, &path, dfd);
error = linux_kern_statat(td, flag, dfd, path, UIO_SYSSPACE, &buf);
if (error == 0)
error = newstat_copyout(&buf, args->statbuf);
LFREEPATH(path);
return (error);
}
#endif /* __i386__ || (__amd64__ && COMPAT_LINUX32) */
int
linux_syncfs(struct thread *td, struct linux_syncfs_args *args)
{
struct mount *mp;
struct vnode *vp;
int error, save;
error = fgetvp(td, args->fd, &cap_fsync_rights, &vp);
if (error != 0)
/*
* Linux syncfs() returns only EBADF, however fgetvp()
* can return EINVAL in case of file descriptor does
* not represent a vnode. XXX.
*/
return (error);
mp = vp->v_mount;
mtx_lock(&mountlist_mtx);
error = vfs_busy(mp, MBF_MNTLSTLOCK);
if (error != 0) {
/* See comment above. */
mtx_unlock(&mountlist_mtx);
goto out;
}
if ((mp->mnt_flag & MNT_RDONLY) == 0 &&
vn_start_write(NULL, &mp, V_NOWAIT) == 0) {
save = curthread_pflags_set(TDP_SYNCIO);
vfs_periodic(mp, MNT_NOWAIT);
VFS_SYNC(mp, MNT_NOWAIT);
curthread_pflags_restore(save);
vn_finished_write(mp);
}
vfs_unbusy(mp);
out:
vrele(vp);
return (error);
}