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freebsd-nq/sys/kern/vfs_vnops.c
Mark Johnston d28af1abf0 vm: Add a mode to vm_object_page_remove() which skips invalid pages 
This will be used to break a deadlock in ZFS between the per-mountpoint
teardown lock and page busy locks.  In particular, when purging data
from the page cache during dataset rollback, we want to avoid blocking
on the busy state of invalid pages since the busying thread may be
blocked on the teardown lock in zfs_getpages().

Add a helper, vn_pages_remove_valid(), for use by filesystems.  Bump
__FreeBSD_version so that the OpenZFS port can make use of the new
helper.

PR:		258208
Reviewed by:	avg, kib, sef
Tested by:	pho (part of a larger patch)
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D32931
2021-11-15 13:01:30 -05:00

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/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* 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.
*
* Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org>
* Copyright (c) 2013, 2014 The FreeBSD Foundation
*
* Portions of this software were developed by Konstantin Belousov
* under sponsorship from the FreeBSD Foundation.
*
* 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 8.2 (Berkeley) 1/21/94
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_hwpmc_hooks.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/disk.h>
#include <sys/fail.h>
#include <sys/fcntl.h>
#include <sys/file.h>
#include <sys/kdb.h>
#include <sys/ktr.h>
#include <sys/stat.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/mman.h>
#include <sys/mount.h>
#include <sys/mutex.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/filio.h>
#include <sys/resourcevar.h>
#include <sys/rwlock.h>
#include <sys/prng.h>
#include <sys/sx.h>
#include <sys/sleepqueue.h>
#include <sys/sysctl.h>
#include <sys/ttycom.h>
#include <sys/conf.h>
#include <sys/syslog.h>
#include <sys/unistd.h>
#include <sys/user.h>
#include <sys/ktrace.h>
#include <security/audit/audit.h>
#include <security/mac/mac_framework.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>
#ifdef HWPMC_HOOKS
#include <sys/pmckern.h>
#endif
static fo_rdwr_t vn_read;
static fo_rdwr_t vn_write;
static fo_rdwr_t vn_io_fault;
static fo_truncate_t vn_truncate;
static fo_ioctl_t vn_ioctl;
static fo_poll_t vn_poll;
static fo_kqfilter_t vn_kqfilter;
static fo_close_t vn_closefile;
static fo_mmap_t vn_mmap;
static fo_fallocate_t vn_fallocate;
static fo_fspacectl_t vn_fspacectl;
struct fileops vnops = {
.fo_read = vn_io_fault,
.fo_write = vn_io_fault,
.fo_truncate = vn_truncate,
.fo_ioctl = vn_ioctl,
.fo_poll = vn_poll,
.fo_kqfilter = vn_kqfilter,
.fo_stat = vn_statfile,
.fo_close = vn_closefile,
.fo_chmod = vn_chmod,
.fo_chown = vn_chown,
.fo_sendfile = vn_sendfile,
.fo_seek = vn_seek,
.fo_fill_kinfo = vn_fill_kinfo,
.fo_mmap = vn_mmap,
.fo_fallocate = vn_fallocate,
.fo_fspacectl = vn_fspacectl,
.fo_flags = DFLAG_PASSABLE | DFLAG_SEEKABLE
};
const u_int io_hold_cnt = 16;
static int vn_io_fault_enable = 1;
SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_enable, CTLFLAG_RWTUN,
&vn_io_fault_enable, 0, "Enable vn_io_fault lock avoidance");
static int vn_io_fault_prefault = 0;
SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_prefault, CTLFLAG_RWTUN,
&vn_io_fault_prefault, 0, "Enable vn_io_fault prefaulting");
static int vn_io_pgcache_read_enable = 1;
SYSCTL_INT(_debug, OID_AUTO, vn_io_pgcache_read_enable, CTLFLAG_RWTUN,
&vn_io_pgcache_read_enable, 0,
"Enable copying from page cache for reads, avoiding fs");
static u_long vn_io_faults_cnt;
SYSCTL_ULONG(_debug, OID_AUTO, vn_io_faults, CTLFLAG_RD,
&vn_io_faults_cnt, 0, "Count of vn_io_fault lock avoidance triggers");
static int vfs_allow_read_dir = 0;
SYSCTL_INT(_security_bsd, OID_AUTO, allow_read_dir, CTLFLAG_RW,
&vfs_allow_read_dir, 0,
"Enable read(2) of directory by root for filesystems that support it");
/*
* Returns true if vn_io_fault mode of handling the i/o request should
* be used.
*/
static bool
do_vn_io_fault(struct vnode *vp, struct uio *uio)
{
struct mount *mp;
return (uio->uio_segflg == UIO_USERSPACE && vp->v_type == VREG &&
(mp = vp->v_mount) != NULL &&
(mp->mnt_kern_flag & MNTK_NO_IOPF) != 0 && vn_io_fault_enable);
}
/*
* Structure used to pass arguments to vn_io_fault1(), to do either
* file- or vnode-based I/O calls.
*/
struct vn_io_fault_args {
enum {
VN_IO_FAULT_FOP,
VN_IO_FAULT_VOP
} kind;
struct ucred *cred;
int flags;
union {
struct fop_args_tag {
struct file *fp;
fo_rdwr_t *doio;
} fop_args;
struct vop_args_tag {
struct vnode *vp;
} vop_args;
} args;
};
static int vn_io_fault1(struct vnode *vp, struct uio *uio,
struct vn_io_fault_args *args, struct thread *td);
int
vn_open(struct nameidata *ndp, int *flagp, int cmode, struct file *fp)
{
struct thread *td = curthread;
return (vn_open_cred(ndp, flagp, cmode, 0, td->td_ucred, fp));
}
static uint64_t
open2nameif(int fmode, u_int vn_open_flags)
{
uint64_t res;
res = ISOPEN | LOCKLEAF;
if ((fmode & O_RESOLVE_BENEATH) != 0)
res |= RBENEATH;
if ((fmode & O_EMPTY_PATH) != 0)
res |= EMPTYPATH;
if ((fmode & FREAD) != 0)
res |= OPENREAD;
if ((fmode & FWRITE) != 0)
res |= OPENWRITE;
if ((vn_open_flags & VN_OPEN_NOAUDIT) == 0)
res |= AUDITVNODE1;
if ((vn_open_flags & VN_OPEN_NOCAPCHECK) != 0)
res |= NOCAPCHECK;
return (res);
}
/*
* Common code for vnode open operations via a name lookup.
* Lookup the vnode and invoke VOP_CREATE if needed.
* Check permissions, and call the VOP_OPEN or VOP_CREATE routine.
*
* Note that this does NOT free nameidata for the successful case,
* due to the NDINIT being done elsewhere.
*/
int
vn_open_cred(struct nameidata *ndp, int *flagp, int cmode, u_int vn_open_flags,
struct ucred *cred, struct file *fp)
{
struct vnode *vp;
struct mount *mp;
struct vattr vat;
struct vattr *vap = &vat;
int fmode, error;
bool first_open;
restart:
first_open = false;
fmode = *flagp;
if ((fmode & (O_CREAT | O_EXCL | O_DIRECTORY)) == (O_CREAT |
O_EXCL | O_DIRECTORY) ||
(fmode & (O_CREAT | O_EMPTY_PATH)) == (O_CREAT | O_EMPTY_PATH))
return (EINVAL);
else if ((fmode & (O_CREAT | O_DIRECTORY)) == O_CREAT) {
ndp->ni_cnd.cn_nameiop = CREATE;
ndp->ni_cnd.cn_flags = open2nameif(fmode, vn_open_flags);
/*
* Set NOCACHE to avoid flushing the cache when
* rolling in many files at once.
*
* Set NC_KEEPPOSENTRY to keep positive entries if they already
* exist despite NOCACHE.
*/
ndp->ni_cnd.cn_flags |= LOCKPARENT | NOCACHE | NC_KEEPPOSENTRY;
if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0)
ndp->ni_cnd.cn_flags |= FOLLOW;
if ((vn_open_flags & VN_OPEN_INVFS) == 0)
bwillwrite();
if ((error = namei(ndp)) != 0)
return (error);
if (ndp->ni_vp == NULL) {
VATTR_NULL(vap);
vap->va_type = VREG;
vap->va_mode = cmode;
if (fmode & O_EXCL)
vap->va_vaflags |= VA_EXCLUSIVE;
if (vn_start_write(ndp->ni_dvp, &mp, V_NOWAIT) != 0) {
NDFREE(ndp, NDF_ONLY_PNBUF);
vput(ndp->ni_dvp);
if ((error = vn_start_write(NULL, &mp,
V_XSLEEP | PCATCH)) != 0)
return (error);
NDREINIT(ndp);
goto restart;
}
if ((vn_open_flags & VN_OPEN_NAMECACHE) != 0)
ndp->ni_cnd.cn_flags |= MAKEENTRY;
#ifdef MAC
error = mac_vnode_check_create(cred, ndp->ni_dvp,
&ndp->ni_cnd, vap);
if (error == 0)
#endif
error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp,
&ndp->ni_cnd, vap);
vp = ndp->ni_vp;
if (error == 0 && (fmode & O_EXCL) != 0 &&
(fmode & (O_EXLOCK | O_SHLOCK)) != 0) {
VI_LOCK(vp);
vp->v_iflag |= VI_FOPENING;
VI_UNLOCK(vp);
first_open = true;
}
VOP_VPUT_PAIR(ndp->ni_dvp, error == 0 ? &vp : NULL,
false);
vn_finished_write(mp);
if (error) {
NDFREE(ndp, NDF_ONLY_PNBUF);
if (error == ERELOOKUP) {
NDREINIT(ndp);
goto restart;
}
return (error);
}
fmode &= ~O_TRUNC;
} else {
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;
}
if (vp->v_type == VDIR) {
error = EISDIR;
goto bad;
}
fmode &= ~O_CREAT;
}
} else {
ndp->ni_cnd.cn_nameiop = LOOKUP;
ndp->ni_cnd.cn_flags = open2nameif(fmode, vn_open_flags);
ndp->ni_cnd.cn_flags |= (fmode & O_NOFOLLOW) != 0 ? NOFOLLOW :
FOLLOW;
if ((fmode & FWRITE) == 0)
ndp->ni_cnd.cn_flags |= LOCKSHARED;
if ((error = namei(ndp)) != 0)
return (error);
vp = ndp->ni_vp;
}
error = vn_open_vnode(vp, fmode, cred, curthread, fp);
if (first_open) {
VI_LOCK(vp);
vp->v_iflag &= ~VI_FOPENING;
wakeup(vp);
VI_UNLOCK(vp);
}
if (error)
goto bad;
*flagp = fmode;
return (0);
bad:
NDFREE(ndp, NDF_ONLY_PNBUF);
vput(vp);
*flagp = fmode;
ndp->ni_vp = NULL;
return (error);
}
static int
vn_open_vnode_advlock(struct vnode *vp, int fmode, struct file *fp)
{
struct flock lf;
int error, lock_flags, type;
ASSERT_VOP_LOCKED(vp, "vn_open_vnode_advlock");
if ((fmode & (O_EXLOCK | O_SHLOCK)) == 0)
return (0);
KASSERT(fp != NULL, ("open with flock requires fp"));
if (fp->f_type != DTYPE_NONE && fp->f_type != DTYPE_VNODE)
return (EOPNOTSUPP);
lock_flags = VOP_ISLOCKED(vp);
VOP_UNLOCK(vp);
lf.l_whence = SEEK_SET;
lf.l_start = 0;
lf.l_len = 0;
lf.l_type = (fmode & O_EXLOCK) != 0 ? F_WRLCK : F_RDLCK;
type = F_FLOCK;
if ((fmode & FNONBLOCK) == 0)
type |= F_WAIT;
if ((fmode & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
type |= F_FIRSTOPEN;
error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type);
if (error == 0)
fp->f_flag |= FHASLOCK;
vn_lock(vp, lock_flags | LK_RETRY);
return (error);
}
/*
* Common code for vnode open operations once a vnode is located.
* Check permissions, and call the VOP_OPEN routine.
*/
int
vn_open_vnode(struct vnode *vp, int fmode, struct ucred *cred,
struct thread *td, struct file *fp)
{
accmode_t accmode;
int error;
if (vp->v_type == VLNK) {
if ((fmode & O_PATH) == 0 || (fmode & FEXEC) != 0)
return (EMLINK);
}
if (vp->v_type != VDIR && fmode & O_DIRECTORY)
return (ENOTDIR);
accmode = 0;
if ((fmode & O_PATH) == 0) {
if (vp->v_type == VSOCK)
return (EOPNOTSUPP);
if ((fmode & (FWRITE | O_TRUNC)) != 0) {
if (vp->v_type == VDIR)
return (EISDIR);
accmode |= VWRITE;
}
if ((fmode & FREAD) != 0)
accmode |= VREAD;
if ((fmode & O_APPEND) && (fmode & FWRITE))
accmode |= VAPPEND;
#ifdef MAC
if ((fmode & O_CREAT) != 0)
accmode |= VCREAT;
#endif
}
if ((fmode & FEXEC) != 0)
accmode |= VEXEC;
#ifdef MAC
if ((fmode & O_VERIFY) != 0)
accmode |= VVERIFY;
error = mac_vnode_check_open(cred, vp, accmode);
if (error != 0)
return (error);
accmode &= ~(VCREAT | VVERIFY);
#endif
if ((fmode & O_CREAT) == 0 && accmode != 0) {
error = VOP_ACCESS(vp, accmode, cred, td);
if (error != 0)
return (error);
}
if ((fmode & O_PATH) != 0) {
if (vp->v_type != VFIFO && vp->v_type != VSOCK &&
VOP_ACCESS(vp, VREAD, cred, td) == 0)
fp->f_flag |= FKQALLOWED;
return (0);
}
if (vp->v_type == VFIFO && VOP_ISLOCKED(vp) != LK_EXCLUSIVE)
vn_lock(vp, LK_UPGRADE | LK_RETRY);
error = VOP_OPEN(vp, fmode, cred, td, fp);
if (error != 0)
return (error);
error = vn_open_vnode_advlock(vp, fmode, fp);
if (error == 0 && (fmode & FWRITE) != 0) {
error = VOP_ADD_WRITECOUNT(vp, 1);
if (error == 0) {
CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d",
__func__, vp, vp->v_writecount);
}
}
/*
* Error from advlock or VOP_ADD_WRITECOUNT() still requires
* calling VOP_CLOSE() to pair with earlier VOP_OPEN().
*/
if (error != 0) {
if (fp != NULL) {
/*
* Arrange the call by having fdrop() to use
* vn_closefile(). This is to satisfy
* filesystems like devfs or tmpfs, which
* override fo_close().
*/
fp->f_flag |= FOPENFAILED;
fp->f_vnode = vp;
if (fp->f_ops == &badfileops) {
fp->f_type = DTYPE_VNODE;
fp->f_ops = &vnops;
}
vref(vp);
} else {
/*
* If there is no fp, due to kernel-mode open,
* we can call VOP_CLOSE() now.
*/
if (vp->v_type != VFIFO && (fmode & FWRITE) != 0 &&
!MNT_EXTENDED_SHARED(vp->v_mount) &&
VOP_ISLOCKED(vp) != LK_EXCLUSIVE)
vn_lock(vp, LK_UPGRADE | LK_RETRY);
(void)VOP_CLOSE(vp, fmode & (FREAD | FWRITE | FEXEC),
cred, td);
}
}
ASSERT_VOP_LOCKED(vp, "vn_open_vnode");
return (error);
}
/*
* Check for write permissions on the specified vnode.
* Prototype text segments cannot be written.
* It is racy.
*/
int
vn_writechk(struct vnode *vp)
{
ASSERT_VOP_LOCKED(vp, "vn_writechk");
/*
* If there's shared text associated with
* the vnode, try to free it up once. If
* we fail, we can't allow writing.
*/
if (VOP_IS_TEXT(vp))
return (ETXTBSY);
return (0);
}
/*
* Vnode close call
*/
static int
vn_close1(struct vnode *vp, int flags, struct ucred *file_cred,
struct thread *td, bool keep_ref)
{
struct mount *mp;
int error, lock_flags;
if (vp->v_type != VFIFO && (flags & FWRITE) == 0 &&
MNT_EXTENDED_SHARED(vp->v_mount))
lock_flags = LK_SHARED;
else
lock_flags = LK_EXCLUSIVE;
vn_start_write(vp, &mp, V_WAIT);
vn_lock(vp, lock_flags | LK_RETRY);
AUDIT_ARG_VNODE1(vp);
if ((flags & (FWRITE | FOPENFAILED)) == FWRITE) {
VOP_ADD_WRITECOUNT_CHECKED(vp, -1);
CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d",
__func__, vp, vp->v_writecount);
}
error = VOP_CLOSE(vp, flags, file_cred, td);
if (keep_ref)
VOP_UNLOCK(vp);
else
vput(vp);
vn_finished_write(mp);
return (error);
}
int
vn_close(struct vnode *vp, int flags, struct ucred *file_cred,
struct thread *td)
{
return (vn_close1(vp, flags, file_cred, td, false));
}
/*
* Heuristic to detect sequential operation.
*/
static int
sequential_heuristic(struct uio *uio, struct file *fp)
{
enum uio_rw rw;
ASSERT_VOP_LOCKED(fp->f_vnode, __func__);
rw = uio->uio_rw;
if (fp->f_flag & FRDAHEAD)
return (fp->f_seqcount[rw] << IO_SEQSHIFT);
/*
* Offset 0 is handled specially. open() sets f_seqcount to 1 so
* that the first I/O is normally considered to be slightly
* sequential. Seeking to offset 0 doesn't change sequentiality
* unless previous seeks have reduced f_seqcount to 0, in which
* case offset 0 is not special.
*/
if ((uio->uio_offset == 0 && fp->f_seqcount[rw] > 0) ||
uio->uio_offset == fp->f_nextoff[rw]) {
/*
* f_seqcount is in units of fixed-size blocks so that it
* depends mainly on the amount of sequential I/O and not
* much on the number of sequential I/O's. The fixed size
* of 16384 is hard-coded here since it is (not quite) just
* a magic size that works well here. This size is more
* closely related to the best I/O size for real disks than
* to any block size used by software.
*/
if (uio->uio_resid >= IO_SEQMAX * 16384)
fp->f_seqcount[rw] = IO_SEQMAX;
else {
fp->f_seqcount[rw] += howmany(uio->uio_resid, 16384);
if (fp->f_seqcount[rw] > IO_SEQMAX)
fp->f_seqcount[rw] = IO_SEQMAX;
}
return (fp->f_seqcount[rw] << IO_SEQSHIFT);
}
/* Not sequential. Quickly draw-down sequentiality. */
if (fp->f_seqcount[rw] > 1)
fp->f_seqcount[rw] = 1;
else
fp->f_seqcount[rw] = 0;
return (0);
}
/*
* Package up an I/O request on a vnode into a uio and do it.
*/
int
vn_rdwr(enum uio_rw rw, struct vnode *vp, void *base, int len, off_t offset,
enum uio_seg segflg, int ioflg, struct ucred *active_cred,
struct ucred *file_cred, ssize_t *aresid, struct thread *td)
{
struct uio auio;
struct iovec aiov;
struct mount *mp;
struct ucred *cred;
void *rl_cookie;
struct vn_io_fault_args args;
int error, lock_flags;
if (offset < 0 && vp->v_type != VCHR)
return (EINVAL);
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_td = td;
error = 0;
if ((ioflg & IO_NODELOCKED) == 0) {
if ((ioflg & IO_RANGELOCKED) == 0) {
if (rw == UIO_READ) {
rl_cookie = vn_rangelock_rlock(vp, offset,
offset + len);
} else if ((ioflg & IO_APPEND) != 0) {
rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX);
} else {
rl_cookie = vn_rangelock_wlock(vp, offset,
offset + len);
}
} else
rl_cookie = NULL;
mp = NULL;
if (rw == UIO_WRITE) {
if (vp->v_type != VCHR &&
(error = vn_start_write(vp, &mp, V_WAIT | PCATCH))
!= 0)
goto out;
lock_flags = vn_lktype_write(mp, vp);
} else
lock_flags = LK_SHARED;
vn_lock(vp, lock_flags | LK_RETRY);
} else
rl_cookie = NULL;
ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
#ifdef MAC
if ((ioflg & IO_NOMACCHECK) == 0) {
if (rw == UIO_READ)
error = mac_vnode_check_read(active_cred, file_cred,
vp);
else
error = mac_vnode_check_write(active_cred, file_cred,
vp);
}
#endif
if (error == 0) {
if (file_cred != NULL)
cred = file_cred;
else
cred = active_cred;
if (do_vn_io_fault(vp, &auio)) {
args.kind = VN_IO_FAULT_VOP;
args.cred = cred;
args.flags = ioflg;
args.args.vop_args.vp = vp;
error = vn_io_fault1(vp, &auio, &args, td);
} else if (rw == UIO_READ) {
error = VOP_READ(vp, &auio, ioflg, cred);
} else /* if (rw == UIO_WRITE) */ {
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) {
VOP_UNLOCK(vp);
if (mp != NULL)
vn_finished_write(mp);
}
out:
if (rl_cookie != NULL)
vn_rangelock_unlock(vp, rl_cookie);
return (error);
}
/*
* Package up an I/O request on a vnode into a uio and do it. The I/O
* request is split up into smaller chunks and we try to avoid saturating
* the buffer cache while potentially holding a vnode locked, so we
* check bwillwrite() before calling vn_rdwr(). We also call kern_yield()
* to give other processes a chance to lock the vnode (either other processes
* core'ing the same binary, or unrelated processes scanning the directory).
*/
int
vn_rdwr_inchunks(enum uio_rw rw, struct vnode *vp, void *base, size_t len,
off_t offset, enum uio_seg segflg, int ioflg, struct ucred *active_cred,
struct ucred *file_cred, size_t *aresid, struct thread *td)
{
int error = 0;
ssize_t iaresid;
do {
int chunk;
/*
* Force `offset' to a multiple of MAXBSIZE except possibly
* for the first chunk, so that filesystems only need to
* write full blocks except possibly for the first and last
* chunks.
*/
chunk = MAXBSIZE - (uoff_t)offset % MAXBSIZE;
if (chunk > len)
chunk = len;
if (rw != UIO_READ && vp->v_type == VREG)
bwillwrite();
iaresid = 0;
error = vn_rdwr(rw, vp, base, chunk, offset, segflg,
ioflg, active_cred, file_cred, &iaresid, td);
len -= chunk; /* aresid calc already includes length */
if (error)
break;
offset += chunk;
base = (char *)base + chunk;
kern_yield(PRI_USER);
} while (len);
if (aresid)
*aresid = len + iaresid;
return (error);
}
#if OFF_MAX <= LONG_MAX
off_t
foffset_lock(struct file *fp, int flags)
{
volatile short *flagsp;
off_t res;
short state;
KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed"));
if ((flags & FOF_NOLOCK) != 0)
return (atomic_load_long(&fp->f_offset));
/*
* According to McKusick the vn lock was protecting f_offset here.
* It is now protected by the FOFFSET_LOCKED flag.
*/
flagsp = &fp->f_vnread_flags;
if (atomic_cmpset_acq_16(flagsp, 0, FOFFSET_LOCKED))
return (atomic_load_long(&fp->f_offset));
sleepq_lock(&fp->f_vnread_flags);
state = atomic_load_16(flagsp);
for (;;) {
if ((state & FOFFSET_LOCKED) == 0) {
if (!atomic_fcmpset_acq_16(flagsp, &state,
FOFFSET_LOCKED))
continue;
break;
}
if ((state & FOFFSET_LOCK_WAITING) == 0) {
if (!atomic_fcmpset_acq_16(flagsp, &state,
state | FOFFSET_LOCK_WAITING))
continue;
}
DROP_GIANT();
sleepq_add(&fp->f_vnread_flags, NULL, "vofflock", 0, 0);
sleepq_wait(&fp->f_vnread_flags, PUSER -1);
PICKUP_GIANT();
sleepq_lock(&fp->f_vnread_flags);
state = atomic_load_16(flagsp);
}
res = atomic_load_long(&fp->f_offset);
sleepq_release(&fp->f_vnread_flags);
return (res);
}
void
foffset_unlock(struct file *fp, off_t val, int flags)
{
volatile short *flagsp;
short state;
KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed"));
if ((flags & FOF_NOUPDATE) == 0)
atomic_store_long(&fp->f_offset, val);
if ((flags & FOF_NEXTOFF_R) != 0)
fp->f_nextoff[UIO_READ] = val;
if ((flags & FOF_NEXTOFF_W) != 0)
fp->f_nextoff[UIO_WRITE] = val;
if ((flags & FOF_NOLOCK) != 0)
return;
flagsp = &fp->f_vnread_flags;
state = atomic_load_16(flagsp);
if ((state & FOFFSET_LOCK_WAITING) == 0 &&
atomic_cmpset_rel_16(flagsp, state, 0))
return;
sleepq_lock(&fp->f_vnread_flags);
MPASS((fp->f_vnread_flags & FOFFSET_LOCKED) != 0);
MPASS((fp->f_vnread_flags & FOFFSET_LOCK_WAITING) != 0);
fp->f_vnread_flags = 0;
sleepq_broadcast(&fp->f_vnread_flags, SLEEPQ_SLEEP, 0, 0);
sleepq_release(&fp->f_vnread_flags);
}
#else
off_t
foffset_lock(struct file *fp, int flags)
{
struct mtx *mtxp;
off_t res;
KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed"));
mtxp = mtx_pool_find(mtxpool_sleep, fp);
mtx_lock(mtxp);
if ((flags & FOF_NOLOCK) == 0) {
while (fp->f_vnread_flags & FOFFSET_LOCKED) {
fp->f_vnread_flags |= FOFFSET_LOCK_WAITING;
msleep(&fp->f_vnread_flags, mtxp, PUSER -1,
"vofflock", 0);
}
fp->f_vnread_flags |= FOFFSET_LOCKED;
}
res = fp->f_offset;
mtx_unlock(mtxp);
return (res);
}
void
foffset_unlock(struct file *fp, off_t val, int flags)
{
struct mtx *mtxp;
KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed"));
mtxp = mtx_pool_find(mtxpool_sleep, fp);
mtx_lock(mtxp);
if ((flags & FOF_NOUPDATE) == 0)
fp->f_offset = val;
if ((flags & FOF_NEXTOFF_R) != 0)
fp->f_nextoff[UIO_READ] = val;
if ((flags & FOF_NEXTOFF_W) != 0)
fp->f_nextoff[UIO_WRITE] = val;
if ((flags & FOF_NOLOCK) == 0) {
KASSERT((fp->f_vnread_flags & FOFFSET_LOCKED) != 0,
("Lost FOFFSET_LOCKED"));
if (fp->f_vnread_flags & FOFFSET_LOCK_WAITING)
wakeup(&fp->f_vnread_flags);
fp->f_vnread_flags = 0;
}
mtx_unlock(mtxp);
}
#endif
void
foffset_lock_uio(struct file *fp, struct uio *uio, int flags)
{
if ((flags & FOF_OFFSET) == 0)
uio->uio_offset = foffset_lock(fp, flags);
}
void
foffset_unlock_uio(struct file *fp, struct uio *uio, int flags)
{
if ((flags & FOF_OFFSET) == 0)
foffset_unlock(fp, uio->uio_offset, flags);
}
static int
get_advice(struct file *fp, struct uio *uio)
{
struct mtx *mtxp;
int ret;
ret = POSIX_FADV_NORMAL;
if (fp->f_advice == NULL || fp->f_vnode->v_type != VREG)
return (ret);
mtxp = mtx_pool_find(mtxpool_sleep, fp);
mtx_lock(mtxp);
if (fp->f_advice != NULL &&
uio->uio_offset >= fp->f_advice->fa_start &&
uio->uio_offset + uio->uio_resid <= fp->f_advice->fa_end)
ret = fp->f_advice->fa_advice;
mtx_unlock(mtxp);
return (ret);
}
static int
get_write_ioflag(struct file *fp)
{
int ioflag;
struct mount *mp;
struct vnode *vp;
ioflag = 0;
vp = fp->f_vnode;
mp = atomic_load_ptr(&vp->v_mount);
if ((fp->f_flag & O_DIRECT) != 0)
ioflag |= IO_DIRECT;
if ((fp->f_flag & O_FSYNC) != 0 ||
(mp != NULL && (mp->mnt_flag & MNT_SYNCHRONOUS) != 0))
ioflag |= IO_SYNC;
/*
* For O_DSYNC we set both IO_SYNC and IO_DATASYNC, so that VOP_WRITE()
* or VOP_DEALLOCATE() implementations that don't understand IO_DATASYNC
* fall back to full O_SYNC behavior.
*/
if ((fp->f_flag & O_DSYNC) != 0)
ioflag |= IO_SYNC | IO_DATASYNC;
return (ioflag);
}
int
vn_read_from_obj(struct vnode *vp, struct uio *uio)
{
vm_object_t obj;
vm_page_t ma[io_hold_cnt + 2];
off_t off, vsz;
ssize_t resid;
int error, i, j;
MPASS(uio->uio_resid <= ptoa(io_hold_cnt + 2));
obj = atomic_load_ptr(&vp->v_object);
if (obj == NULL)
return (EJUSTRETURN);
/*
* Depends on type stability of vm_objects.
*/
vm_object_pip_add(obj, 1);
if ((obj->flags & OBJ_DEAD) != 0) {
/*
* Note that object might be already reused from the
* vnode, and the OBJ_DEAD flag cleared. This is fine,
* we recheck for DOOMED vnode state after all pages
* are busied, and retract then.
*
* But we check for OBJ_DEAD to ensure that we do not
* busy pages while vm_object_terminate_pages()
* processes the queue.
*/
error = EJUSTRETURN;
goto out_pip;
}
resid = uio->uio_resid;
off = uio->uio_offset;
for (i = 0; resid > 0; i++) {
MPASS(i < io_hold_cnt + 2);
ma[i] = vm_page_grab_unlocked(obj, atop(off),
VM_ALLOC_NOCREAT | VM_ALLOC_SBUSY | VM_ALLOC_IGN_SBUSY |
VM_ALLOC_NOWAIT);
if (ma[i] == NULL)
break;
/*
* Skip invalid pages. Valid mask can be partial only
* at EOF, and we clip later.
*/
if (vm_page_none_valid(ma[i])) {
vm_page_sunbusy(ma[i]);
break;
}
resid -= PAGE_SIZE;
off += PAGE_SIZE;
}
if (i == 0) {
error = EJUSTRETURN;
goto out_pip;
}
/*
* Check VIRF_DOOMED after we busied our pages. Since
* vgonel() terminates the vnode' vm_object, it cannot
* process past pages busied by us.
*/
if (VN_IS_DOOMED(vp)) {
error = EJUSTRETURN;
goto out;
}
resid = PAGE_SIZE - (uio->uio_offset & PAGE_MASK) + ptoa(i - 1);
if (resid > uio->uio_resid)
resid = uio->uio_resid;
/*
* Unlocked read of vnp_size is safe because truncation cannot
* pass busied page. But we load vnp_size into a local
* variable so that possible concurrent extension does not
* break calculation.
*/
#if defined(__powerpc__) && !defined(__powerpc64__)
vsz = obj->un_pager.vnp.vnp_size;
#else
vsz = atomic_load_64(&obj->un_pager.vnp.vnp_size);
#endif
if (uio->uio_offset >= vsz) {
error = EJUSTRETURN;
goto out;
}
if (uio->uio_offset + resid > vsz)
resid = vsz - uio->uio_offset;
error = vn_io_fault_pgmove(ma, uio->uio_offset & PAGE_MASK, resid, uio);
out:
for (j = 0; j < i; j++) {
if (error == 0)
vm_page_reference(ma[j]);
vm_page_sunbusy(ma[j]);
}
out_pip:
vm_object_pip_wakeup(obj);
if (error != 0)
return (error);
return (uio->uio_resid == 0 ? 0 : EJUSTRETURN);
}
/*
* File table vnode read routine.
*/
static int
vn_read(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags,
struct thread *td)
{
struct vnode *vp;
off_t orig_offset;
int error, ioflag;
int advice;
KASSERT(uio->uio_td == td, ("uio_td %p is not td %p",
uio->uio_td, td));
KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET"));
vp = fp->f_vnode;
ioflag = 0;
if (fp->f_flag & FNONBLOCK)
ioflag |= IO_NDELAY;
if (fp->f_flag & O_DIRECT)
ioflag |= IO_DIRECT;
/*
* Try to read from page cache. VIRF_DOOMED check is racy but
* allows us to avoid unneeded work outright.
*/
if (vn_io_pgcache_read_enable && !mac_vnode_check_read_enabled() &&
(vn_irflag_read(vp) & (VIRF_DOOMED | VIRF_PGREAD)) == VIRF_PGREAD) {
error = VOP_READ_PGCACHE(vp, uio, ioflag, fp->f_cred);
if (error == 0) {
fp->f_nextoff[UIO_READ] = uio->uio_offset;
return (0);
}
if (error != EJUSTRETURN)
return (error);
}
advice = get_advice(fp, uio);
vn_lock(vp, LK_SHARED | LK_RETRY);
switch (advice) {
case POSIX_FADV_NORMAL:
case POSIX_FADV_SEQUENTIAL:
case POSIX_FADV_NOREUSE:
ioflag |= sequential_heuristic(uio, fp);
break;
case POSIX_FADV_RANDOM:
/* Disable read-ahead for random I/O. */
break;
}
orig_offset = uio->uio_offset;
#ifdef MAC
error = mac_vnode_check_read(active_cred, fp->f_cred, vp);
if (error == 0)
#endif
error = VOP_READ(vp, uio, ioflag, fp->f_cred);
fp->f_nextoff[UIO_READ] = uio->uio_offset;
VOP_UNLOCK(vp);
if (error == 0 && advice == POSIX_FADV_NOREUSE &&
orig_offset != uio->uio_offset)
/*
* Use POSIX_FADV_DONTNEED to flush pages and buffers
* for the backing file after a POSIX_FADV_NOREUSE
* read(2).
*/
error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1,
POSIX_FADV_DONTNEED);
return (error);
}
/*
* File table vnode write routine.
*/
static int
vn_write(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags,
struct thread *td)
{
struct vnode *vp;
struct mount *mp;
off_t orig_offset;
int error, ioflag;
int advice;
bool need_finished_write;
KASSERT(uio->uio_td == td, ("uio_td %p is not td %p",
uio->uio_td, td));
KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET"));
vp = fp->f_vnode;
if (vp->v_type == VREG)
bwillwrite();
ioflag = IO_UNIT;
if (vp->v_type == VREG && (fp->f_flag & O_APPEND) != 0)
ioflag |= IO_APPEND;
if ((fp->f_flag & FNONBLOCK) != 0)
ioflag |= IO_NDELAY;
ioflag |= get_write_ioflag(fp);
mp = NULL;
need_finished_write = false;
if (vp->v_type != VCHR) {
error = vn_start_write(vp, &mp, V_WAIT | PCATCH);
if (error != 0)
goto unlock;
need_finished_write = true;
}
advice = get_advice(fp, uio);
vn_lock(vp, vn_lktype_write(mp, vp) | LK_RETRY);
switch (advice) {
case POSIX_FADV_NORMAL:
case POSIX_FADV_SEQUENTIAL:
case POSIX_FADV_NOREUSE:
ioflag |= sequential_heuristic(uio, fp);
break;
case POSIX_FADV_RANDOM:
/* XXX: Is this correct? */
break;
}
orig_offset = uio->uio_offset;
#ifdef MAC
error = mac_vnode_check_write(active_cred, fp->f_cred, vp);
if (error == 0)
#endif
error = VOP_WRITE(vp, uio, ioflag, fp->f_cred);
fp->f_nextoff[UIO_WRITE] = uio->uio_offset;
VOP_UNLOCK(vp);
if (need_finished_write)
vn_finished_write(mp);
if (error == 0 && advice == POSIX_FADV_NOREUSE &&
orig_offset != uio->uio_offset)
/*
* Use POSIX_FADV_DONTNEED to flush pages and buffers
* for the backing file after a POSIX_FADV_NOREUSE
* write(2).
*/
error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1,
POSIX_FADV_DONTNEED);
unlock:
return (error);
}
/*
* The vn_io_fault() is a wrapper around vn_read() and vn_write() to
* prevent the following deadlock:
*
* Assume that the thread A reads from the vnode vp1 into userspace
* buffer buf1 backed by the pages of vnode vp2. If a page in buf1 is
* currently not resident, then system ends up with the call chain
* vn_read() -> VOP_READ(vp1) -> uiomove() -> [Page Fault] ->
* vm_fault(buf1) -> vnode_pager_getpages(vp2) -> VOP_GETPAGES(vp2)
* which establishes lock order vp1->vn_lock, then vp2->vn_lock.
* If, at the same time, thread B reads from vnode vp2 into buffer buf2
* backed by the pages of vnode vp1, and some page in buf2 is not
* resident, we get a reversed order vp2->vn_lock, then vp1->vn_lock.
*
* To prevent the lock order reversal and deadlock, vn_io_fault() does
* not allow page faults to happen during VOP_READ() or VOP_WRITE().
* Instead, it first tries to do the whole range i/o with pagefaults
* disabled. If all pages in the i/o buffer are resident and mapped,
* VOP will succeed (ignoring the genuine filesystem errors).
* Otherwise, we get back EFAULT, and vn_io_fault() falls back to do
* i/o in chunks, with all pages in the chunk prefaulted and held
* using vm_fault_quick_hold_pages().
*
* Filesystems using this deadlock avoidance scheme should use the
* array of the held pages from uio, saved in the curthread->td_ma,
* instead of doing uiomove(). A helper function
* vn_io_fault_uiomove() converts uiomove request into
* uiomove_fromphys() over td_ma array.
*
* Since vnode locks do not cover the whole i/o anymore, rangelocks
* make the current i/o request atomic with respect to other i/os and
* truncations.
*/
/*
* Decode vn_io_fault_args and perform the corresponding i/o.
*/
static int
vn_io_fault_doio(struct vn_io_fault_args *args, struct uio *uio,
struct thread *td)
{
int error, save;
error = 0;
save = vm_fault_disable_pagefaults();
switch (args->kind) {
case VN_IO_FAULT_FOP:
error = (args->args.fop_args.doio)(args->args.fop_args.fp,
uio, args->cred, args->flags, td);
break;
case VN_IO_FAULT_VOP:
if (uio->uio_rw == UIO_READ) {
error = VOP_READ(args->args.vop_args.vp, uio,
args->flags, args->cred);
} else if (uio->uio_rw == UIO_WRITE) {
error = VOP_WRITE(args->args.vop_args.vp, uio,
args->flags, args->cred);
}
break;
default:
panic("vn_io_fault_doio: unknown kind of io %d %d",
args->kind, uio->uio_rw);
}
vm_fault_enable_pagefaults(save);
return (error);
}
static int
vn_io_fault_touch(char *base, const struct uio *uio)
{
int r;
r = fubyte(base);
if (r == -1 || (uio->uio_rw == UIO_READ && subyte(base, r) == -1))
return (EFAULT);
return (0);
}
static int
vn_io_fault_prefault_user(const struct uio *uio)
{
char *base;
const struct iovec *iov;
size_t len;
ssize_t resid;
int error, i;
KASSERT(uio->uio_segflg == UIO_USERSPACE,
("vn_io_fault_prefault userspace"));
error = i = 0;
iov = uio->uio_iov;
resid = uio->uio_resid;
base = iov->iov_base;
len = iov->iov_len;
while (resid > 0) {
error = vn_io_fault_touch(base, uio);
if (error != 0)
break;
if (len < PAGE_SIZE) {
if (len != 0) {
error = vn_io_fault_touch(base + len - 1, uio);
if (error != 0)
break;
resid -= len;
}
if (++i >= uio->uio_iovcnt)
break;
iov = uio->uio_iov + i;
base = iov->iov_base;
len = iov->iov_len;
} else {
len -= PAGE_SIZE;
base += PAGE_SIZE;
resid -= PAGE_SIZE;
}
}
return (error);
}
/*
* Common code for vn_io_fault(), agnostic to the kind of i/o request.
* Uses vn_io_fault_doio() to make the call to an actual i/o function.
* Used from vn_rdwr() and vn_io_fault(), which encode the i/o request
* into args and call vn_io_fault1() to handle faults during the user
* mode buffer accesses.
*/
static int
vn_io_fault1(struct vnode *vp, struct uio *uio, struct vn_io_fault_args *args,
struct thread *td)
{
vm_page_t ma[io_hold_cnt + 2];
struct uio *uio_clone, short_uio;
struct iovec short_iovec[1];
vm_page_t *prev_td_ma;
vm_prot_t prot;
vm_offset_t addr, end;
size_t len, resid;
ssize_t adv;
int error, cnt, saveheld, prev_td_ma_cnt;
if (vn_io_fault_prefault) {
error = vn_io_fault_prefault_user(uio);
if (error != 0)
return (error); /* Or ignore ? */
}
prot = uio->uio_rw == UIO_READ ? VM_PROT_WRITE : VM_PROT_READ;
/*
* The UFS follows IO_UNIT directive and replays back both
* uio_offset and uio_resid if an error is encountered during the
* operation. But, since the iovec may be already advanced,
* uio is still in an inconsistent state.
*
* Cache a copy of the original uio, which is advanced to the redo
* point using UIO_NOCOPY below.
*/
uio_clone = cloneuio(uio);
resid = uio->uio_resid;
short_uio.uio_segflg = UIO_USERSPACE;
short_uio.uio_rw = uio->uio_rw;
short_uio.uio_td = uio->uio_td;
error = vn_io_fault_doio(args, uio, td);
if (error != EFAULT)
goto out;
atomic_add_long(&vn_io_faults_cnt, 1);
uio_clone->uio_segflg = UIO_NOCOPY;
uiomove(NULL, resid - uio->uio_resid, uio_clone);
uio_clone->uio_segflg = uio->uio_segflg;
saveheld = curthread_pflags_set(TDP_UIOHELD);
prev_td_ma = td->td_ma;
prev_td_ma_cnt = td->td_ma_cnt;
while (uio_clone->uio_resid != 0) {
len = uio_clone->uio_iov->iov_len;
if (len == 0) {
KASSERT(uio_clone->uio_iovcnt >= 1,
("iovcnt underflow"));
uio_clone->uio_iov++;
uio_clone->uio_iovcnt--;
continue;
}
if (len > ptoa(io_hold_cnt))
len = ptoa(io_hold_cnt);
addr = (uintptr_t)uio_clone->uio_iov->iov_base;
end = round_page(addr + len);
if (end < addr) {
error = EFAULT;
break;
}
cnt = atop(end - trunc_page(addr));
/*
* A perfectly misaligned address and length could cause
* both the start and the end of the chunk to use partial
* page. +2 accounts for such a situation.
*/
cnt = vm_fault_quick_hold_pages(&td->td_proc->p_vmspace->vm_map,
addr, len, prot, ma, io_hold_cnt + 2);
if (cnt == -1) {
error = EFAULT;
break;
}
short_uio.uio_iov = &short_iovec[0];
short_iovec[0].iov_base = (void *)addr;
short_uio.uio_iovcnt = 1;
short_uio.uio_resid = short_iovec[0].iov_len = len;
short_uio.uio_offset = uio_clone->uio_offset;
td->td_ma = ma;
td->td_ma_cnt = cnt;
error = vn_io_fault_doio(args, &short_uio, td);
vm_page_unhold_pages(ma, cnt);
adv = len - short_uio.uio_resid;
uio_clone->uio_iov->iov_base =
(char *)uio_clone->uio_iov->iov_base + adv;
uio_clone->uio_iov->iov_len -= adv;
uio_clone->uio_resid -= adv;
uio_clone->uio_offset += adv;
uio->uio_resid -= adv;
uio->uio_offset += adv;
if (error != 0 || adv == 0)
break;
}
td->td_ma = prev_td_ma;
td->td_ma_cnt = prev_td_ma_cnt;
curthread_pflags_restore(saveheld);
out:
free(uio_clone, M_IOV);
return (error);
}
static int
vn_io_fault(struct file *fp, struct uio *uio, struct ucred *active_cred,
int flags, struct thread *td)
{
fo_rdwr_t *doio;
struct vnode *vp;
void *rl_cookie;
struct vn_io_fault_args args;
int error;
doio = uio->uio_rw == UIO_READ ? vn_read : vn_write;
vp = fp->f_vnode;
/*
* The ability to read(2) on a directory has historically been
* allowed for all users, but this can and has been the source of
* at least one security issue in the past. As such, it is now hidden
* away behind a sysctl for those that actually need it to use it, and
* restricted to root when it's turned on to make it relatively safe to
* leave on for longer sessions of need.
*/
if (vp->v_type == VDIR) {
KASSERT(uio->uio_rw == UIO_READ,
("illegal write attempted on a directory"));
if (!vfs_allow_read_dir)
return (EISDIR);
if ((error = priv_check(td, PRIV_VFS_READ_DIR)) != 0)
return (EISDIR);
}
foffset_lock_uio(fp, uio, flags);
if (do_vn_io_fault(vp, uio)) {
args.kind = VN_IO_FAULT_FOP;
args.args.fop_args.fp = fp;
args.args.fop_args.doio = doio;
args.cred = active_cred;
args.flags = flags | FOF_OFFSET;
if (uio->uio_rw == UIO_READ) {
rl_cookie = vn_rangelock_rlock(vp, uio->uio_offset,
uio->uio_offset + uio->uio_resid);
} else if ((fp->f_flag & O_APPEND) != 0 ||
(flags & FOF_OFFSET) == 0) {
/* For appenders, punt and lock the whole range. */
rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX);
} else {
rl_cookie = vn_rangelock_wlock(vp, uio->uio_offset,
uio->uio_offset + uio->uio_resid);
}
error = vn_io_fault1(vp, uio, &args, td);
vn_rangelock_unlock(vp, rl_cookie);
} else {
error = doio(fp, uio, active_cred, flags | FOF_OFFSET, td);
}
foffset_unlock_uio(fp, uio, flags);
return (error);
}
/*
* Helper function to perform the requested uiomove operation using
* the held pages for io->uio_iov[0].iov_base buffer instead of
* copyin/copyout. Access to the pages with uiomove_fromphys()
* instead of iov_base prevents page faults that could occur due to
* pmap_collect() invalidating the mapping created by
* vm_fault_quick_hold_pages(), or pageout daemon, page laundry or
* object cleanup revoking the write access from page mappings.
*
* Filesystems specified MNTK_NO_IOPF shall use vn_io_fault_uiomove()
* instead of plain uiomove().
*/
int
vn_io_fault_uiomove(char *data, int xfersize, struct uio *uio)
{
struct uio transp_uio;
struct iovec transp_iov[1];
struct thread *td;
size_t adv;
int error, pgadv;
td = curthread;
if ((td->td_pflags & TDP_UIOHELD) == 0 ||
uio->uio_segflg != UIO_USERSPACE)
return (uiomove(data, xfersize, uio));
KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt));
transp_iov[0].iov_base = data;
transp_uio.uio_iov = &transp_iov[0];
transp_uio.uio_iovcnt = 1;
if (xfersize > uio->uio_resid)
xfersize = uio->uio_resid;
transp_uio.uio_resid = transp_iov[0].iov_len = xfersize;
transp_uio.uio_offset = 0;
transp_uio.uio_segflg = UIO_SYSSPACE;
/*
* Since transp_iov points to data, and td_ma page array
* corresponds to original uio->uio_iov, we need to invert the
* direction of the i/o operation as passed to
* uiomove_fromphys().
*/
switch (uio->uio_rw) {
case UIO_WRITE:
transp_uio.uio_rw = UIO_READ;
break;
case UIO_READ:
transp_uio.uio_rw = UIO_WRITE;
break;
}
transp_uio.uio_td = uio->uio_td;
error = uiomove_fromphys(td->td_ma,
((vm_offset_t)uio->uio_iov->iov_base) & PAGE_MASK,
xfersize, &transp_uio);
adv = xfersize - transp_uio.uio_resid;
pgadv =
(((vm_offset_t)uio->uio_iov->iov_base + adv) >> PAGE_SHIFT) -
(((vm_offset_t)uio->uio_iov->iov_base) >> PAGE_SHIFT);
td->td_ma += pgadv;
KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt,
pgadv));
td->td_ma_cnt -= pgadv;
uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + adv;
uio->uio_iov->iov_len -= adv;
uio->uio_resid -= adv;
uio->uio_offset += adv;
return (error);
}
int
vn_io_fault_pgmove(vm_page_t ma[], vm_offset_t offset, int xfersize,
struct uio *uio)
{
struct thread *td;
vm_offset_t iov_base;
int cnt, pgadv;
td = curthread;
if ((td->td_pflags & TDP_UIOHELD) == 0 ||
uio->uio_segflg != UIO_USERSPACE)
return (uiomove_fromphys(ma, offset, xfersize, uio));
KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt));
cnt = xfersize > uio->uio_resid ? uio->uio_resid : xfersize;
iov_base = (vm_offset_t)uio->uio_iov->iov_base;
switch (uio->uio_rw) {
case UIO_WRITE:
pmap_copy_pages(td->td_ma, iov_base & PAGE_MASK, ma,
offset, cnt);
break;
case UIO_READ:
pmap_copy_pages(ma, offset, td->td_ma, iov_base & PAGE_MASK,
cnt);
break;
}
pgadv = ((iov_base + cnt) >> PAGE_SHIFT) - (iov_base >> PAGE_SHIFT);
td->td_ma += pgadv;
KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt,
pgadv));
td->td_ma_cnt -= pgadv;
uio->uio_iov->iov_base = (char *)(iov_base + cnt);
uio->uio_iov->iov_len -= cnt;
uio->uio_resid -= cnt;
uio->uio_offset += cnt;
return (0);
}
/*
* File table truncate routine.
*/
static int
vn_truncate(struct file *fp, off_t length, struct ucred *active_cred,
struct thread *td)
{
struct mount *mp;
struct vnode *vp;
void *rl_cookie;
int error;
vp = fp->f_vnode;
retry:
/*
* Lock the whole range for truncation. Otherwise split i/o
* might happen partly before and partly after the truncation.
*/
rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX);
error = vn_start_write(vp, &mp, V_WAIT | PCATCH);
if (error)
goto out1;
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
AUDIT_ARG_VNODE1(vp);
if (vp->v_type == VDIR) {
error = EISDIR;
goto out;
}
#ifdef MAC
error = mac_vnode_check_write(active_cred, fp->f_cred, vp);
if (error)
goto out;
#endif
error = vn_truncate_locked(vp, length, (fp->f_flag & O_FSYNC) != 0,
fp->f_cred);
out:
VOP_UNLOCK(vp);
vn_finished_write(mp);
out1:
vn_rangelock_unlock(vp, rl_cookie);
if (error == ERELOOKUP)
goto retry;
return (error);
}
/*
* Truncate a file that is already locked.
*/
int
vn_truncate_locked(struct vnode *vp, off_t length, bool sync,
struct ucred *cred)
{
struct vattr vattr;
int error;
error = VOP_ADD_WRITECOUNT(vp, 1);
if (error == 0) {
VATTR_NULL(&vattr);
vattr.va_size = length;
if (sync)
vattr.va_vaflags |= VA_SYNC;
error = VOP_SETATTR(vp, &vattr, cred);
VOP_ADD_WRITECOUNT_CHECKED(vp, -1);
}
return (error);
}
/*
* File table vnode stat routine.
*/
int
vn_statfile(struct file *fp, struct stat *sb, struct ucred *active_cred)
{
struct vnode *vp = fp->f_vnode;
int error;
vn_lock(vp, LK_SHARED | LK_RETRY);
error = VOP_STAT(vp, sb, active_cred, fp->f_cred);
VOP_UNLOCK(vp);
return (error);
}
/*
* File table vnode ioctl routine.
*/
static int
vn_ioctl(struct file *fp, u_long com, void *data, struct ucred *active_cred,
struct thread *td)
{
struct vattr vattr;
struct vnode *vp;
struct fiobmap2_arg *bmarg;
int error;
vp = fp->f_vnode;
switch (vp->v_type) {
case VDIR:
case VREG:
switch (com) {
case FIONREAD:
vn_lock(vp, LK_SHARED | LK_RETRY);
error = VOP_GETATTR(vp, &vattr, active_cred);
VOP_UNLOCK(vp);
if (error == 0)
*(int *)data = vattr.va_size - fp->f_offset;
return (error);
case FIOBMAP2:
bmarg = (struct fiobmap2_arg *)data;
vn_lock(vp, LK_SHARED | LK_RETRY);
#ifdef MAC
error = mac_vnode_check_read(active_cred, fp->f_cred,
vp);
if (error == 0)
#endif
error = VOP_BMAP(vp, bmarg->bn, NULL,
&bmarg->bn, &bmarg->runp, &bmarg->runb);
VOP_UNLOCK(vp);
return (error);
case FIONBIO:
case FIOASYNC:
return (0);
default:
return (VOP_IOCTL(vp, com, data, fp->f_flag,
active_cred, td));
}
break;
case VCHR:
return (VOP_IOCTL(vp, com, data, fp->f_flag,
active_cred, td));
default:
return (ENOTTY);
}
}
/*
* File table vnode poll routine.
*/
static int
vn_poll(struct file *fp, int events, struct ucred *active_cred,
struct thread *td)
{
struct vnode *vp;
int error;
vp = fp->f_vnode;
#if defined(MAC) || defined(AUDIT)
if (AUDITING_TD(td) || mac_vnode_check_poll_enabled()) {
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
AUDIT_ARG_VNODE1(vp);
error = mac_vnode_check_poll(active_cred, fp->f_cred, vp);
VOP_UNLOCK(vp);
if (error != 0)
return (error);
}
#endif
error = VOP_POLL(vp, events, fp->f_cred, td);
return (error);
}
/*
* Acquire the requested lock and then check for validity. LK_RETRY
* permits vn_lock to return doomed vnodes.
*/
static int __noinline
_vn_lock_fallback(struct vnode *vp, int flags, const char *file, int line,
int error)
{
KASSERT((flags & LK_RETRY) == 0 || error == 0,
("vn_lock: error %d incompatible with flags %#x", error, flags));
if (error == 0)
VNASSERT(VN_IS_DOOMED(vp), vp, ("vnode not doomed"));
if ((flags & LK_RETRY) == 0) {
if (error == 0) {
VOP_UNLOCK(vp);
error = ENOENT;
}
return (error);
}
/*
* LK_RETRY case.
*
* Nothing to do if we got the lock.
*/
if (error == 0)
return (0);
/*
* Interlock was dropped by the call in _vn_lock.
*/
flags &= ~LK_INTERLOCK;
do {
error = VOP_LOCK1(vp, flags, file, line);
} while (error != 0);
return (0);
}
int
_vn_lock(struct vnode *vp, int flags, const char *file, int line)
{
int error;
VNASSERT((flags & LK_TYPE_MASK) != 0, vp,
("vn_lock: no locktype (%d passed)", flags));
VNPASS(vp->v_holdcnt > 0, vp);
error = VOP_LOCK1(vp, flags, file, line);
if (__predict_false(error != 0 || VN_IS_DOOMED(vp)))
return (_vn_lock_fallback(vp, flags, file, line, error));
return (0);
}
/*
* File table vnode close routine.
*/
static int
vn_closefile(struct file *fp, struct thread *td)
{
struct vnode *vp;
struct flock lf;
int error;
bool ref;
vp = fp->f_vnode;
fp->f_ops = &badfileops;
ref = (fp->f_flag & FHASLOCK) != 0;
error = vn_close1(vp, fp->f_flag, fp->f_cred, td, ref);
if (__predict_false(ref)) {
lf.l_whence = SEEK_SET;
lf.l_start = 0;
lf.l_len = 0;
lf.l_type = F_UNLCK;
(void) VOP_ADVLOCK(vp, fp, F_UNLCK, &lf, F_FLOCK);
vrele(vp);
}
return (error);
}
/*
* Preparing to start a filesystem write operation. If the operation is
* permitted, then we bump the count of operations in progress and
* proceed. If a suspend request is in progress, we wait until the
* suspension is over, and then proceed.
*/
static int
vn_start_write_refed(struct mount *mp, int flags, bool mplocked)
{
struct mount_pcpu *mpcpu;
int error, mflags;
if (__predict_true(!mplocked) && (flags & V_XSLEEP) == 0 &&
vfs_op_thread_enter(mp, mpcpu)) {
MPASS((mp->mnt_kern_flag & MNTK_SUSPEND) == 0);
vfs_mp_count_add_pcpu(mpcpu, writeopcount, 1);
vfs_op_thread_exit(mp, mpcpu);
return (0);
}
if (mplocked)
mtx_assert(MNT_MTX(mp), MA_OWNED);
else
MNT_ILOCK(mp);
error = 0;
/*
* Check on status of suspension.
*/
if ((curthread->td_pflags & TDP_IGNSUSP) == 0 ||
mp->mnt_susp_owner != curthread) {
mflags = ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0 ?
(flags & PCATCH) : 0) | (PUSER - 1);
while ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) {
if (flags & V_NOWAIT) {
error = EWOULDBLOCK;
goto unlock;
}
error = msleep(&mp->mnt_flag, MNT_MTX(mp), mflags,
"suspfs", 0);
if (error)
goto unlock;
}
}
if (flags & V_XSLEEP)
goto unlock;
mp->mnt_writeopcount++;
unlock:
if (error != 0 || (flags & V_XSLEEP) != 0)
MNT_REL(mp);
MNT_IUNLOCK(mp);
return (error);
}
int
vn_start_write(struct vnode *vp, struct mount **mpp, int flags)
{
struct mount *mp;
int error;
KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL),
("V_MNTREF requires mp"));
error = 0;
/*
* If a vnode is provided, get and return the mount point that
* to which it will write.
*/
if (vp != NULL) {
if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) {
*mpp = NULL;
if (error != EOPNOTSUPP)
return (error);
return (0);
}
}
if ((mp = *mpp) == NULL)
return (0);
/*
* VOP_GETWRITEMOUNT() returns with the mp refcount held through
* a vfs_ref().
* As long as a vnode is not provided we need to acquire a
* refcount for the provided mountpoint too, in order to
* emulate a vfs_ref().
*/
if (vp == NULL && (flags & V_MNTREF) == 0)
vfs_ref(mp);
return (vn_start_write_refed(mp, flags, false));
}
/*
* Secondary suspension. Used by operations such as vop_inactive
* routines that are needed by the higher level functions. These
* are allowed to proceed until all the higher level functions have
* completed (indicated by mnt_writeopcount dropping to zero). At that
* time, these operations are halted until the suspension is over.
*/
int
vn_start_secondary_write(struct vnode *vp, struct mount **mpp, int flags)
{
struct mount *mp;
int error;
KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL),
("V_MNTREF requires mp"));
retry:
if (vp != NULL) {
if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) {
*mpp = NULL;
if (error != EOPNOTSUPP)
return (error);
return (0);
}
}
/*
* If we are not suspended or have not yet reached suspended
* mode, then let the operation proceed.
*/
if ((mp = *mpp) == NULL)
return (0);
/*
* VOP_GETWRITEMOUNT() returns with the mp refcount held through
* a vfs_ref().
* As long as a vnode is not provided we need to acquire a
* refcount for the provided mountpoint too, in order to
* emulate a vfs_ref().
*/
MNT_ILOCK(mp);
if (vp == NULL && (flags & V_MNTREF) == 0)
MNT_REF(mp);
if ((mp->mnt_kern_flag & (MNTK_SUSPENDED | MNTK_SUSPEND2)) == 0) {
mp->mnt_secondary_writes++;
mp->mnt_secondary_accwrites++;
MNT_IUNLOCK(mp);
return (0);
}
if (flags & V_NOWAIT) {
MNT_REL(mp);
MNT_IUNLOCK(mp);
return (EWOULDBLOCK);
}
/*
* Wait for the suspension to finish.
*/
error = msleep(&mp->mnt_flag, MNT_MTX(mp), (PUSER - 1) | PDROP |
((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0 ? (flags & PCATCH) : 0),
"suspfs", 0);
vfs_rel(mp);
if (error == 0)
goto retry;
return (error);
}
/*
* Filesystem write operation has completed. If we are suspending and this
* operation is the last one, notify the suspender that the suspension is
* now in effect.
*/
void
vn_finished_write(struct mount *mp)
{
struct mount_pcpu *mpcpu;
int c;
if (mp == NULL)
return;
if (vfs_op_thread_enter(mp, mpcpu)) {
vfs_mp_count_sub_pcpu(mpcpu, writeopcount, 1);
vfs_mp_count_sub_pcpu(mpcpu, ref, 1);
vfs_op_thread_exit(mp, mpcpu);
return;
}
MNT_ILOCK(mp);
vfs_assert_mount_counters(mp);
MNT_REL(mp);
c = --mp->mnt_writeopcount;
if (mp->mnt_vfs_ops == 0) {
MPASS((mp->mnt_kern_flag & MNTK_SUSPEND) == 0);
MNT_IUNLOCK(mp);
return;
}
if (c < 0)
vfs_dump_mount_counters(mp);
if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && c == 0)
wakeup(&mp->mnt_writeopcount);
MNT_IUNLOCK(mp);
}
/*
* Filesystem secondary write operation has completed. If we are
* suspending and this operation is the last one, notify the suspender
* that the suspension is now in effect.
*/
void
vn_finished_secondary_write(struct mount *mp)
{
if (mp == NULL)
return;
MNT_ILOCK(mp);
MNT_REL(mp);
mp->mnt_secondary_writes--;
if (mp->mnt_secondary_writes < 0)
panic("vn_finished_secondary_write: neg cnt");
if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 &&
mp->mnt_secondary_writes <= 0)
wakeup(&mp->mnt_secondary_writes);
MNT_IUNLOCK(mp);
}
/*
* Request a filesystem to suspend write operations.
*/
int
vfs_write_suspend(struct mount *mp, int flags)
{
int error;
vfs_op_enter(mp);
MNT_ILOCK(mp);
vfs_assert_mount_counters(mp);
if (mp->mnt_susp_owner == curthread) {
vfs_op_exit_locked(mp);
MNT_IUNLOCK(mp);
return (EALREADY);
}
while (mp->mnt_kern_flag & MNTK_SUSPEND)
msleep(&mp->mnt_flag, MNT_MTX(mp), PUSER - 1, "wsuspfs", 0);
/*
* Unmount holds a write reference on the mount point. If we
* own busy reference and drain for writers, we deadlock with
* the reference draining in the unmount path. Callers of
* vfs_write_suspend() must specify VS_SKIP_UNMOUNT if
* vfs_busy() reference is owned and caller is not in the
* unmount context.
*/
if ((flags & VS_SKIP_UNMOUNT) != 0 &&
(mp->mnt_kern_flag & MNTK_UNMOUNT) != 0) {
vfs_op_exit_locked(mp);
MNT_IUNLOCK(mp);
return (EBUSY);
}
mp->mnt_kern_flag |= MNTK_SUSPEND;
mp->mnt_susp_owner = curthread;
if (mp->mnt_writeopcount > 0)
(void) msleep(&mp->mnt_writeopcount,
MNT_MTX(mp), (PUSER - 1)|PDROP, "suspwt", 0);
else
MNT_IUNLOCK(mp);
if ((error = VFS_SYNC(mp, MNT_SUSPEND)) != 0) {
vfs_write_resume(mp, 0);
/* vfs_write_resume does vfs_op_exit() for us */
}
return (error);
}
/*
* Request a filesystem to resume write operations.
*/
void
vfs_write_resume(struct mount *mp, int flags)
{
MNT_ILOCK(mp);
if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) {
KASSERT(mp->mnt_susp_owner == curthread, ("mnt_susp_owner"));
mp->mnt_kern_flag &= ~(MNTK_SUSPEND | MNTK_SUSPEND2 |
MNTK_SUSPENDED);
mp->mnt_susp_owner = NULL;
wakeup(&mp->mnt_writeopcount);
wakeup(&mp->mnt_flag);
curthread->td_pflags &= ~TDP_IGNSUSP;
if ((flags & VR_START_WRITE) != 0) {
MNT_REF(mp);
mp->mnt_writeopcount++;
}
MNT_IUNLOCK(mp);
if ((flags & VR_NO_SUSPCLR) == 0)
VFS_SUSP_CLEAN(mp);
vfs_op_exit(mp);
} else if ((flags & VR_START_WRITE) != 0) {
MNT_REF(mp);
vn_start_write_refed(mp, 0, true);
} else {
MNT_IUNLOCK(mp);
}
}
/*
* Helper loop around vfs_write_suspend() for filesystem unmount VFS
* methods.
*/
int
vfs_write_suspend_umnt(struct mount *mp)
{
int error;
KASSERT((curthread->td_pflags & TDP_IGNSUSP) == 0,
("vfs_write_suspend_umnt: recursed"));
/* dounmount() already called vn_start_write(). */
for (;;) {
vn_finished_write(mp);
error = vfs_write_suspend(mp, 0);
if (error != 0) {
vn_start_write(NULL, &mp, V_WAIT);
return (error);
}
MNT_ILOCK(mp);
if ((mp->mnt_kern_flag & MNTK_SUSPENDED) != 0)
break;
MNT_IUNLOCK(mp);
vn_start_write(NULL, &mp, V_WAIT);
}
mp->mnt_kern_flag &= ~(MNTK_SUSPENDED | MNTK_SUSPEND2);
wakeup(&mp->mnt_flag);
MNT_IUNLOCK(mp);
curthread->td_pflags |= TDP_IGNSUSP;
return (0);
}
/*
* Implement kqueues for files by translating it to vnode operation.
*/
static int
vn_kqfilter(struct file *fp, struct knote *kn)
{
return (VOP_KQFILTER(fp->f_vnode, kn));
}
int
vn_kqfilter_opath(struct file *fp, struct knote *kn)
{
if ((fp->f_flag & FKQALLOWED) == 0)
return (EBADF);
return (vn_kqfilter(fp, kn));
}
/*
* Simplified in-kernel wrapper calls for extended attribute access.
* Both calls pass in a NULL credential, authorizing as "kernel" access.
* Set IO_NODELOCKED in ioflg if the vnode is already locked.
*/
int
vn_extattr_get(struct vnode *vp, int ioflg, int attrnamespace,
const char *attrname, int *buflen, char *buf, struct thread *td)
{
struct uio auio;
struct iovec iov;
int error;
iov.iov_len = *buflen;
iov.iov_base = buf;
auio.uio_iov = &iov;
auio.uio_iovcnt = 1;
auio.uio_rw = UIO_READ;
auio.uio_segflg = UIO_SYSSPACE;
auio.uio_td = td;
auio.uio_offset = 0;
auio.uio_resid = *buflen;
if ((ioflg & IO_NODELOCKED) == 0)
vn_lock(vp, LK_SHARED | LK_RETRY);
ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
/* authorize attribute retrieval as kernel */
error = VOP_GETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, NULL,
td);
if ((ioflg & IO_NODELOCKED) == 0)
VOP_UNLOCK(vp);
if (error == 0) {
*buflen = *buflen - auio.uio_resid;
}
return (error);
}
/*
* XXX failure mode if partially written?
*/
int
vn_extattr_set(struct vnode *vp, int ioflg, int attrnamespace,
const char *attrname, int buflen, char *buf, struct thread *td)
{
struct uio auio;
struct iovec iov;
struct mount *mp;
int error;
iov.iov_len = buflen;
iov.iov_base = buf;
auio.uio_iov = &iov;
auio.uio_iovcnt = 1;
auio.uio_rw = UIO_WRITE;
auio.uio_segflg = UIO_SYSSPACE;
auio.uio_td = td;
auio.uio_offset = 0;
auio.uio_resid = buflen;
if ((ioflg & IO_NODELOCKED) == 0) {
if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0)
return (error);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
}
ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
/* authorize attribute setting as kernel */
error = VOP_SETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, td);
if ((ioflg & IO_NODELOCKED) == 0) {
vn_finished_write(mp);
VOP_UNLOCK(vp);
}
return (error);
}
int
vn_extattr_rm(struct vnode *vp, int ioflg, int attrnamespace,
const char *attrname, struct thread *td)
{
struct mount *mp;
int error;
if ((ioflg & IO_NODELOCKED) == 0) {
if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0)
return (error);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
}
ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
/* authorize attribute removal as kernel */
error = VOP_DELETEEXTATTR(vp, attrnamespace, attrname, NULL, td);
if (error == EOPNOTSUPP)
error = VOP_SETEXTATTR(vp, attrnamespace, attrname, NULL,
NULL, td);
if ((ioflg & IO_NODELOCKED) == 0) {
vn_finished_write(mp);
VOP_UNLOCK(vp);
}
return (error);
}
static int
vn_get_ino_alloc_vget(struct mount *mp, void *arg, int lkflags,
struct vnode **rvp)
{
return (VFS_VGET(mp, *(ino_t *)arg, lkflags, rvp));
}
int
vn_vget_ino(struct vnode *vp, ino_t ino, int lkflags, struct vnode **rvp)
{
return (vn_vget_ino_gen(vp, vn_get_ino_alloc_vget, &ino,
lkflags, rvp));
}
int
vn_vget_ino_gen(struct vnode *vp, vn_get_ino_t alloc, void *alloc_arg,
int lkflags, struct vnode **rvp)
{
struct mount *mp;
int ltype, error;
ASSERT_VOP_LOCKED(vp, "vn_vget_ino_get");
mp = vp->v_mount;
ltype = VOP_ISLOCKED(vp);
KASSERT(ltype == LK_EXCLUSIVE || ltype == LK_SHARED,
("vn_vget_ino: vp not locked"));
error = vfs_busy(mp, MBF_NOWAIT);
if (error != 0) {
vfs_ref(mp);
VOP_UNLOCK(vp);
error = vfs_busy(mp, 0);
vn_lock(vp, ltype | LK_RETRY);
vfs_rel(mp);
if (error != 0)
return (ENOENT);
if (VN_IS_DOOMED(vp)) {
vfs_unbusy(mp);
return (ENOENT);
}
}
VOP_UNLOCK(vp);
error = alloc(mp, alloc_arg, lkflags, rvp);
vfs_unbusy(mp);
if (error != 0 || *rvp != vp)
vn_lock(vp, ltype | LK_RETRY);
if (VN_IS_DOOMED(vp)) {
if (error == 0) {
if (*rvp == vp)
vunref(vp);
else
vput(*rvp);
}
error = ENOENT;
}
return (error);
}
int
vn_rlimit_fsize(const struct vnode *vp, const struct uio *uio,
struct thread *td)
{
off_t lim;
bool ktr_write;
if (td == NULL)
return (0);
/*
* There are conditions where the limit is to be ignored.
* However, since it is almost never reached, check it first.
*/
ktr_write = (td->td_pflags & TDP_INKTRACE) != 0;
lim = lim_cur(td, RLIMIT_FSIZE);
if (__predict_false(ktr_write))
lim = td->td_ktr_io_lim;
if (__predict_true((uoff_t)uio->uio_offset + uio->uio_resid <= lim))
return (0);
/*
* The limit is reached.
*/
if (vp->v_type != VREG ||
(td->td_pflags2 & TDP2_ACCT) != 0)
return (0);
if (!ktr_write || ktr_filesize_limit_signal) {
PROC_LOCK(td->td_proc);
kern_psignal(td->td_proc, SIGXFSZ);
PROC_UNLOCK(td->td_proc);
}
return (EFBIG);
}
int
vn_chmod(struct file *fp, mode_t mode, struct ucred *active_cred,
struct thread *td)
{
struct vnode *vp;
vp = fp->f_vnode;
#ifdef AUDIT
vn_lock(vp, LK_SHARED | LK_RETRY);
AUDIT_ARG_VNODE1(vp);
VOP_UNLOCK(vp);
#endif
return (setfmode(td, active_cred, vp, mode));
}
int
vn_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred,
struct thread *td)
{
struct vnode *vp;
vp = fp->f_vnode;
#ifdef AUDIT
vn_lock(vp, LK_SHARED | LK_RETRY);
AUDIT_ARG_VNODE1(vp);
VOP_UNLOCK(vp);
#endif
return (setfown(td, active_cred, vp, uid, gid));
}
/*
* Remove pages in the range ["start", "end") from the vnode's VM object. If
* "end" is 0, then the range extends to the end of the object.
*/
void
vn_pages_remove(struct vnode *vp, vm_pindex_t start, vm_pindex_t end)
{
vm_object_t object;
if ((object = vp->v_object) == NULL)
return;
VM_OBJECT_WLOCK(object);
vm_object_page_remove(object, start, end, 0);
VM_OBJECT_WUNLOCK(object);
}
/*
* Like vn_pages_remove(), but skips invalid pages, which by definition are not
* mapped into any process' address space. Filesystems may use this in
* preference to vn_pages_remove() to avoid blocking on pages busied in
* preparation for a VOP_GETPAGES.
*/
void
vn_pages_remove_valid(struct vnode *vp, vm_pindex_t start, vm_pindex_t end)
{
vm_object_t object;
if ((object = vp->v_object) == NULL)
return;
VM_OBJECT_WLOCK(object);
vm_object_page_remove(object, start, end, OBJPR_VALIDONLY);
VM_OBJECT_WUNLOCK(object);
}
int
vn_bmap_seekhole_locked(struct vnode *vp, u_long cmd, off_t *off,
struct ucred *cred)
{
struct vattr va;
daddr_t bn, bnp;
uint64_t bsize;
off_t noff;
int error;
KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA,
("%s: Wrong command %lu", __func__, cmd));
ASSERT_VOP_LOCKED(vp, "vn_bmap_seekhole_locked");
if (vp->v_type != VREG) {
error = ENOTTY;
goto out;
}
error = VOP_GETATTR(vp, &va, cred);
if (error != 0)
goto out;
noff = *off;
if (noff >= va.va_size) {
error = ENXIO;
goto out;
}
bsize = vp->v_mount->mnt_stat.f_iosize;
for (bn = noff / bsize; noff < va.va_size; bn++, noff += bsize -
noff % bsize) {
error = VOP_BMAP(vp, bn, NULL, &bnp, NULL, NULL);
if (error == EOPNOTSUPP) {
error = ENOTTY;
goto out;
}
if ((bnp == -1 && cmd == FIOSEEKHOLE) ||
(bnp != -1 && cmd == FIOSEEKDATA)) {
noff = bn * bsize;
if (noff < *off)
noff = *off;
goto out;
}
}
if (noff > va.va_size)
noff = va.va_size;
/* noff == va.va_size. There is an implicit hole at the end of file. */
if (cmd == FIOSEEKDATA)
error = ENXIO;
out:
if (error == 0)
*off = noff;
return (error);
}
int
vn_bmap_seekhole(struct vnode *vp, u_long cmd, off_t *off, struct ucred *cred)
{
int error;
KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA,
("%s: Wrong command %lu", __func__, cmd));
if (vn_lock(vp, LK_SHARED) != 0)
return (EBADF);
error = vn_bmap_seekhole_locked(vp, cmd, off, cred);
VOP_UNLOCK(vp);
return (error);
}
int
vn_seek(struct file *fp, off_t offset, int whence, struct thread *td)
{
struct ucred *cred;
struct vnode *vp;
struct vattr vattr;
off_t foffset, size;
int error, noneg;
cred = td->td_ucred;
vp = fp->f_vnode;
foffset = foffset_lock(fp, 0);
noneg = (vp->v_type != VCHR);
error = 0;
switch (whence) {
case L_INCR:
if (noneg &&
(foffset < 0 ||
(offset > 0 && foffset > OFF_MAX - offset))) {
error = EOVERFLOW;
break;
}
offset += foffset;
break;
case L_XTND:
vn_lock(vp, LK_SHARED | LK_RETRY);
error = VOP_GETATTR(vp, &vattr, cred);
VOP_UNLOCK(vp);
if (error)
break;
/*
* If the file references a disk device, then fetch
* the media size and use that to determine the ending
* offset.
*/
if (vattr.va_size == 0 && vp->v_type == VCHR &&
fo_ioctl(fp, DIOCGMEDIASIZE, &size, cred, td) == 0)
vattr.va_size = size;
if (noneg &&
(vattr.va_size > OFF_MAX ||
(offset > 0 && vattr.va_size > OFF_MAX - offset))) {
error = EOVERFLOW;
break;
}
offset += vattr.va_size;
break;
case L_SET:
break;
case SEEK_DATA:
error = fo_ioctl(fp, FIOSEEKDATA, &offset, cred, td);
if (error == ENOTTY)
error = EINVAL;
break;
case SEEK_HOLE:
error = fo_ioctl(fp, FIOSEEKHOLE, &offset, cred, td);
if (error == ENOTTY)
error = EINVAL;
break;
default:
error = EINVAL;
}
if (error == 0 && noneg && offset < 0)
error = EINVAL;
if (error != 0)
goto drop;
VFS_KNOTE_UNLOCKED(vp, 0);
td->td_uretoff.tdu_off = offset;
drop:
foffset_unlock(fp, offset, error != 0 ? FOF_NOUPDATE : 0);
return (error);
}
int
vn_utimes_perm(struct vnode *vp, struct vattr *vap, struct ucred *cred,
struct thread *td)
{
int error;
/*
* Grant permission if the caller is the owner of the file, or
* the super-user, or has ACL_WRITE_ATTRIBUTES permission on
* on the file. If the time pointer is null, then write
* permission on the file is also sufficient.
*
* From NFSv4.1, draft 21, 6.2.1.3.1, Discussion of Mask Attributes:
* A user having ACL_WRITE_DATA or ACL_WRITE_ATTRIBUTES
* will be allowed to set the times [..] to the current
* server time.
*/
error = VOP_ACCESSX(vp, VWRITE_ATTRIBUTES, cred, td);
if (error != 0 && (vap->va_vaflags & VA_UTIMES_NULL) != 0)
error = VOP_ACCESS(vp, VWRITE, cred, td);
return (error);
}
int
vn_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
{
struct vnode *vp;
int error;
if (fp->f_type == DTYPE_FIFO)
kif->kf_type = KF_TYPE_FIFO;
else
kif->kf_type = KF_TYPE_VNODE;
vp = fp->f_vnode;
vref(vp);
FILEDESC_SUNLOCK(fdp);
error = vn_fill_kinfo_vnode(vp, kif);
vrele(vp);
FILEDESC_SLOCK(fdp);
return (error);
}
static inline void
vn_fill_junk(struct kinfo_file *kif)
{
size_t len, olen;
/*
* Simulate vn_fullpath returning changing values for a given
* vp during e.g. coredump.
*/
len = (arc4random() % (sizeof(kif->kf_path) - 2)) + 1;
olen = strlen(kif->kf_path);
if (len < olen)
strcpy(&kif->kf_path[len - 1], "$");
else
for (; olen < len; olen++)
strcpy(&kif->kf_path[olen], "A");
}
int
vn_fill_kinfo_vnode(struct vnode *vp, struct kinfo_file *kif)
{
struct vattr va;
char *fullpath, *freepath;
int error;
kif->kf_un.kf_file.kf_file_type = vntype_to_kinfo(vp->v_type);
freepath = NULL;
fullpath = "-";
error = vn_fullpath(vp, &fullpath, &freepath);
if (error == 0) {
strlcpy(kif->kf_path, fullpath, sizeof(kif->kf_path));
}
if (freepath != NULL)
free(freepath, M_TEMP);
KFAIL_POINT_CODE(DEBUG_FP, fill_kinfo_vnode__random_path,
vn_fill_junk(kif);
);
/*
* Retrieve vnode attributes.
*/
va.va_fsid = VNOVAL;
va.va_rdev = NODEV;
vn_lock(vp, LK_SHARED | LK_RETRY);
error = VOP_GETATTR(vp, &va, curthread->td_ucred);
VOP_UNLOCK(vp);
if (error != 0)
return (error);
if (va.va_fsid != VNOVAL)
kif->kf_un.kf_file.kf_file_fsid = va.va_fsid;
else
kif->kf_un.kf_file.kf_file_fsid =
vp->v_mount->mnt_stat.f_fsid.val[0];
kif->kf_un.kf_file.kf_file_fsid_freebsd11 =
kif->kf_un.kf_file.kf_file_fsid; /* truncate */
kif->kf_un.kf_file.kf_file_fileid = va.va_fileid;
kif->kf_un.kf_file.kf_file_mode = MAKEIMODE(va.va_type, va.va_mode);
kif->kf_un.kf_file.kf_file_size = va.va_size;
kif->kf_un.kf_file.kf_file_rdev = va.va_rdev;
kif->kf_un.kf_file.kf_file_rdev_freebsd11 =
kif->kf_un.kf_file.kf_file_rdev; /* truncate */
return (0);
}
int
vn_mmap(struct file *fp, vm_map_t map, vm_offset_t *addr, vm_size_t size,
vm_prot_t prot, vm_prot_t cap_maxprot, int flags, vm_ooffset_t foff,
struct thread *td)
{
#ifdef HWPMC_HOOKS
struct pmckern_map_in pkm;
#endif
struct mount *mp;
struct vnode *vp;
vm_object_t object;
vm_prot_t maxprot;
boolean_t writecounted;
int error;
#if defined(COMPAT_FREEBSD7) || defined(COMPAT_FREEBSD6) || \
defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4)
/*
* POSIX shared-memory objects are defined to have
* kernel persistence, and are not defined to support
* read(2)/write(2) -- or even open(2). Thus, we can
* use MAP_ASYNC to trade on-disk coherence for speed.
* The shm_open(3) library routine turns on the FPOSIXSHM
* flag to request this behavior.
*/
if ((fp->f_flag & FPOSIXSHM) != 0)
flags |= MAP_NOSYNC;
#endif
vp = fp->f_vnode;
/*
* Ensure that file and memory protections are
* compatible. Note that we only worry about
* writability if mapping is shared; in this case,
* current and max prot are dictated by the open file.
* XXX use the vnode instead? Problem is: what
* credentials do we use for determination? What if
* proc does a setuid?
*/
mp = vp->v_mount;
if (mp != NULL && (mp->mnt_flag & MNT_NOEXEC) != 0) {
maxprot = VM_PROT_NONE;
if ((prot & VM_PROT_EXECUTE) != 0)
return (EACCES);
} else
maxprot = VM_PROT_EXECUTE;
if ((fp->f_flag & FREAD) != 0)
maxprot |= VM_PROT_READ;
else if ((prot & VM_PROT_READ) != 0)
return (EACCES);
/*
* If we are sharing potential changes via MAP_SHARED and we
* are trying to get write permission although we opened it
* without asking for it, bail out.
*/
if ((flags & MAP_SHARED) != 0) {
if ((fp->f_flag & FWRITE) != 0)
maxprot |= VM_PROT_WRITE;
else if ((prot & VM_PROT_WRITE) != 0)
return (EACCES);
} else {
maxprot |= VM_PROT_WRITE;
cap_maxprot |= VM_PROT_WRITE;
}
maxprot &= cap_maxprot;
/*
* For regular files and shared memory, POSIX requires that
* the value of foff be a legitimate offset within the data
* object. In particular, negative offsets are invalid.
* Blocking negative offsets and overflows here avoids
* possible wraparound or user-level access into reserved
* ranges of the data object later. In contrast, POSIX does
* not dictate how offsets are used by device drivers, so in
* the case of a device mapping a negative offset is passed
* on.
*/
if (
#ifdef _LP64
size > OFF_MAX ||
#endif
foff > OFF_MAX - size)
return (EINVAL);
writecounted = FALSE;
error = vm_mmap_vnode(td, size, prot, &maxprot, &flags, vp,
&foff, &object, &writecounted);
if (error != 0)
return (error);
error = vm_mmap_object(map, addr, size, prot, maxprot, flags, object,
foff, writecounted, td);
if (error != 0) {
/*
* If this mapping was accounted for in the vnode's
* writecount, then undo that now.
*/
if (writecounted)
vm_pager_release_writecount(object, 0, size);
vm_object_deallocate(object);
}
#ifdef HWPMC_HOOKS
/* Inform hwpmc(4) if an executable is being mapped. */
if (PMC_HOOK_INSTALLED(PMC_FN_MMAP)) {
if ((prot & VM_PROT_EXECUTE) != 0 && error == 0) {
pkm.pm_file = vp;
pkm.pm_address = (uintptr_t) *addr;
PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_MMAP, (void *) &pkm);
}
}
#endif
return (error);
}
void
vn_fsid(struct vnode *vp, struct vattr *va)
{
fsid_t *f;
f = &vp->v_mount->mnt_stat.f_fsid;
va->va_fsid = (uint32_t)f->val[1];
va->va_fsid <<= sizeof(f->val[1]) * NBBY;
va->va_fsid += (uint32_t)f->val[0];
}
int
vn_fsync_buf(struct vnode *vp, int waitfor)
{
struct buf *bp, *nbp;
struct bufobj *bo;
struct mount *mp;
int error, maxretry;
error = 0;
maxretry = 10000; /* large, arbitrarily chosen */
mp = NULL;
if (vp->v_type == VCHR) {
VI_LOCK(vp);
mp = vp->v_rdev->si_mountpt;
VI_UNLOCK(vp);
}
bo = &vp->v_bufobj;
BO_LOCK(bo);
loop1:
/*
* MARK/SCAN initialization to avoid infinite loops.
*/
TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs) {
bp->b_vflags &= ~BV_SCANNED;
bp->b_error = 0;
}
/*
* Flush all dirty buffers associated with a vnode.
*/
loop2:
TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) {
if ((bp->b_vflags & BV_SCANNED) != 0)
continue;
bp->b_vflags |= BV_SCANNED;
if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL)) {
if (waitfor != MNT_WAIT)
continue;
if (BUF_LOCK(bp,
LK_EXCLUSIVE | LK_INTERLOCK | LK_SLEEPFAIL,
BO_LOCKPTR(bo)) != 0) {
BO_LOCK(bo);
goto loop1;
}
BO_LOCK(bo);
}
BO_UNLOCK(bo);
KASSERT(bp->b_bufobj == bo,
("bp %p wrong b_bufobj %p should be %p",
bp, bp->b_bufobj, bo));
if ((bp->b_flags & B_DELWRI) == 0)
panic("fsync: not dirty");
if ((vp->v_object != NULL) && (bp->b_flags & B_CLUSTEROK)) {
vfs_bio_awrite(bp);
} else {
bremfree(bp);
bawrite(bp);
}
if (maxretry < 1000)
pause("dirty", hz < 1000 ? 1 : hz / 1000);
BO_LOCK(bo);
goto loop2;
}
/*
* If synchronous the caller expects us to completely resolve all
* dirty buffers in the system. Wait for in-progress I/O to
* complete (which could include background bitmap writes), then
* retry if dirty blocks still exist.
*/
if (waitfor == MNT_WAIT) {
bufobj_wwait(bo, 0, 0);
if (bo->bo_dirty.bv_cnt > 0) {
/*
* If we are unable to write any of these buffers
* then we fail now rather than trying endlessly
* to write them out.
*/
TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs)
if ((error = bp->b_error) != 0)
break;
if ((mp != NULL && mp->mnt_secondary_writes > 0) ||
(error == 0 && --maxretry >= 0))
goto loop1;
if (error == 0)
error = EAGAIN;
}
}
BO_UNLOCK(bo);
if (error != 0)
vn_printf(vp, "fsync: giving up on dirty (error = %d) ", error);
return (error);
}
/*
* Copies a byte range from invp to outvp. Calls VOP_COPY_FILE_RANGE()
* or vn_generic_copy_file_range() after rangelocking the byte ranges,
* to do the actual copy.
* vn_generic_copy_file_range() is factored out, so it can be called
* from a VOP_COPY_FILE_RANGE() call as well, but handles vnodes from
* different file systems.
*/
int
vn_copy_file_range(struct vnode *invp, off_t *inoffp, struct vnode *outvp,
off_t *outoffp, size_t *lenp, unsigned int flags, struct ucred *incred,
struct ucred *outcred, struct thread *fsize_td)
{
int error;
size_t len;
uint64_t uval;
len = *lenp;
*lenp = 0; /* For error returns. */
error = 0;
/* Do some sanity checks on the arguments. */
if (invp->v_type == VDIR || outvp->v_type == VDIR)
error = EISDIR;
else if (*inoffp < 0 || *outoffp < 0 ||
invp->v_type != VREG || outvp->v_type != VREG)
error = EINVAL;
if (error != 0)
goto out;
/* Ensure offset + len does not wrap around. */
uval = *inoffp;
uval += len;
if (uval > INT64_MAX)
len = INT64_MAX - *inoffp;
uval = *outoffp;
uval += len;
if (uval > INT64_MAX)
len = INT64_MAX - *outoffp;
if (len == 0)
goto out;
/*
* If the two vnode are for the same file system, call
* VOP_COPY_FILE_RANGE(), otherwise call vn_generic_copy_file_range()
* which can handle copies across multiple file systems.
*/
*lenp = len;
if (invp->v_mount == outvp->v_mount)
error = VOP_COPY_FILE_RANGE(invp, inoffp, outvp, outoffp,
lenp, flags, incred, outcred, fsize_td);
else
error = vn_generic_copy_file_range(invp, inoffp, outvp,
outoffp, lenp, flags, incred, outcred, fsize_td);
out:
return (error);
}
/*
* Test len bytes of data starting at dat for all bytes == 0.
* Return true if all bytes are zero, false otherwise.
* Expects dat to be well aligned.
*/
static bool
mem_iszero(void *dat, int len)
{
int i;
const u_int *p;
const char *cp;
for (p = dat; len > 0; len -= sizeof(*p), p++) {
if (len >= sizeof(*p)) {
if (*p != 0)
return (false);
} else {
cp = (const char *)p;
for (i = 0; i < len; i++, cp++)
if (*cp != '\0')
return (false);
}
}
return (true);
}
/*
* Look for a hole in the output file and, if found, adjust *outoffp
* and *xferp to skip past the hole.
* *xferp is the entire hole length to be written and xfer2 is how many bytes
* to be written as 0's upon return.
*/
static off_t
vn_skip_hole(struct vnode *outvp, off_t xfer2, off_t *outoffp, off_t *xferp,
off_t *dataoffp, off_t *holeoffp, struct ucred *cred)
{
int error;
off_t delta;
if (*holeoffp == 0 || *holeoffp <= *outoffp) {
*dataoffp = *outoffp;
error = VOP_IOCTL(outvp, FIOSEEKDATA, dataoffp, 0, cred,
curthread);
if (error == 0) {
*holeoffp = *dataoffp;
error = VOP_IOCTL(outvp, FIOSEEKHOLE, holeoffp, 0, cred,
curthread);
}
if (error != 0 || *holeoffp == *dataoffp) {
/*
* Since outvp is unlocked, it may be possible for
* another thread to do a truncate(), lseek(), write()
* creating a hole at startoff between the above
* VOP_IOCTL() calls, if the other thread does not do
* rangelocking.
* If that happens, *holeoffp == *dataoffp and finding
* the hole has failed, so disable vn_skip_hole().
*/
*holeoffp = -1; /* Disable use of vn_skip_hole(). */
return (xfer2);
}
KASSERT(*dataoffp >= *outoffp,
("vn_skip_hole: dataoff=%jd < outoff=%jd",
(intmax_t)*dataoffp, (intmax_t)*outoffp));
KASSERT(*holeoffp > *dataoffp,
("vn_skip_hole: holeoff=%jd <= dataoff=%jd",
(intmax_t)*holeoffp, (intmax_t)*dataoffp));
}
/*
* If there is a hole before the data starts, advance *outoffp and
* *xferp past the hole.
*/
if (*dataoffp > *outoffp) {
delta = *dataoffp - *outoffp;
if (delta >= *xferp) {
/* Entire *xferp is a hole. */
*outoffp += *xferp;
*xferp = 0;
return (0);
}
*xferp -= delta;
*outoffp += delta;
xfer2 = MIN(xfer2, *xferp);
}
/*
* If a hole starts before the end of this xfer2, reduce this xfer2 so
* that the write ends at the start of the hole.
* *holeoffp should always be greater than *outoffp, but for the
* non-INVARIANTS case, check this to make sure xfer2 remains a sane
* value.
*/
if (*holeoffp > *outoffp && *holeoffp < *outoffp + xfer2)
xfer2 = *holeoffp - *outoffp;
return (xfer2);
}
/*
* Write an xfer sized chunk to outvp in blksize blocks from dat.
* dat is a maximum of blksize in length and can be written repeatedly in
* the chunk.
* If growfile == true, just grow the file via vn_truncate_locked() instead
* of doing actual writes.
* If checkhole == true, a hole is being punched, so skip over any hole
* already in the output file.
*/
static int
vn_write_outvp(struct vnode *outvp, char *dat, off_t outoff, off_t xfer,
u_long blksize, bool growfile, bool checkhole, struct ucred *cred)
{
struct mount *mp;
off_t dataoff, holeoff, xfer2;
int error;
/*
* Loop around doing writes of blksize until write has been completed.
* Lock/unlock on each loop iteration so that a bwillwrite() can be
* done for each iteration, since the xfer argument can be very
* large if there is a large hole to punch in the output file.
*/
error = 0;
holeoff = 0;
do {
xfer2 = MIN(xfer, blksize);
if (checkhole) {
/*
* Punching a hole. Skip writing if there is
* already a hole in the output file.
*/
xfer2 = vn_skip_hole(outvp, xfer2, &outoff, &xfer,
&dataoff, &holeoff, cred);
if (xfer == 0)
break;
if (holeoff < 0)
checkhole = false;
KASSERT(xfer2 > 0, ("vn_write_outvp: xfer2=%jd",
(intmax_t)xfer2));
}
bwillwrite();
mp = NULL;
error = vn_start_write(outvp, &mp, V_WAIT);
if (error != 0)
break;
if (growfile) {
error = vn_lock(outvp, LK_EXCLUSIVE);
if (error == 0) {
error = vn_truncate_locked(outvp, outoff + xfer,
false, cred);
VOP_UNLOCK(outvp);
}
} else {
error = vn_lock(outvp, vn_lktype_write(mp, outvp));
if (error == 0) {
error = vn_rdwr(UIO_WRITE, outvp, dat, xfer2,
outoff, UIO_SYSSPACE, IO_NODELOCKED,
curthread->td_ucred, cred, NULL, curthread);
outoff += xfer2;
xfer -= xfer2;
VOP_UNLOCK(outvp);
}
}
if (mp != NULL)
vn_finished_write(mp);
} while (!growfile && xfer > 0 && error == 0);
return (error);
}
/*
* Copy a byte range of one file to another. This function can handle the
* case where invp and outvp are on different file systems.
* It can also be called by a VOP_COPY_FILE_RANGE() to do the work, if there
* is no better file system specific way to do it.
*/
int
vn_generic_copy_file_range(struct vnode *invp, off_t *inoffp,
struct vnode *outvp, off_t *outoffp, size_t *lenp, unsigned int flags,
struct ucred *incred, struct ucred *outcred, struct thread *fsize_td)
{
struct vattr va, inva;
struct mount *mp;
struct uio io;
off_t startoff, endoff, xfer, xfer2;
u_long blksize;
int error, interrupted;
bool cantseek, readzeros, eof, lastblock, holetoeof;
ssize_t aresid;
size_t copylen, len, rem, savlen;
char *dat;
long holein, holeout;
struct timespec curts, endts;
holein = holeout = 0;
savlen = len = *lenp;
error = 0;
interrupted = 0;
dat = NULL;
error = vn_lock(invp, LK_SHARED);
if (error != 0)
goto out;
if (VOP_PATHCONF(invp, _PC_MIN_HOLE_SIZE, &holein) != 0)
holein = 0;
if (holein > 0)
error = VOP_GETATTR(invp, &inva, incred);
VOP_UNLOCK(invp);
if (error != 0)
goto out;
mp = NULL;
error = vn_start_write(outvp, &mp, V_WAIT);
if (error == 0)
error = vn_lock(outvp, LK_EXCLUSIVE);
if (error == 0) {
/*
* If fsize_td != NULL, do a vn_rlimit_fsize() call,
* now that outvp is locked.
*/
if (fsize_td != NULL) {
io.uio_offset = *outoffp;
io.uio_resid = len;
error = vn_rlimit_fsize(outvp, &io, fsize_td);
if (error != 0)
error = EFBIG;
}
if (VOP_PATHCONF(outvp, _PC_MIN_HOLE_SIZE, &holeout) != 0)
holeout = 0;
/*
* Holes that are past EOF do not need to be written as a block
* of zero bytes. So, truncate the output file as far as
* possible and then use va.va_size to decide if writing 0
* bytes is necessary in the loop below.
*/
if (error == 0)
error = VOP_GETATTR(outvp, &va, outcred);
if (error == 0 && va.va_size > *outoffp && va.va_size <=
*outoffp + len) {
#ifdef MAC
error = mac_vnode_check_write(curthread->td_ucred,
outcred, outvp);
if (error == 0)
#endif
error = vn_truncate_locked(outvp, *outoffp,
false, outcred);
if (error == 0)
va.va_size = *outoffp;
}
VOP_UNLOCK(outvp);
}
if (mp != NULL)
vn_finished_write(mp);
if (error != 0)
goto out;
/*
* Set the blksize to the larger of the hole sizes for invp and outvp.
* If hole sizes aren't available, set the blksize to the larger
* f_iosize of invp and outvp.
* This code expects the hole sizes and f_iosizes to be powers of 2.
* This value is clipped at 4Kbytes and 1Mbyte.
*/
blksize = MAX(holein, holeout);
/* Clip len to end at an exact multiple of hole size. */
if (blksize > 1) {
rem = *inoffp % blksize;
if (rem > 0)
rem = blksize - rem;
if (len > rem && len - rem > blksize)
len = savlen = rounddown(len - rem, blksize) + rem;
}
if (blksize <= 1)
blksize = MAX(invp->v_mount->mnt_stat.f_iosize,
outvp->v_mount->mnt_stat.f_iosize);
if (blksize < 4096)
blksize = 4096;
else if (blksize > 1024 * 1024)
blksize = 1024 * 1024;
dat = malloc(blksize, M_TEMP, M_WAITOK);
/*
* If VOP_IOCTL(FIOSEEKHOLE) works for invp, use it and FIOSEEKDATA
* to find holes. Otherwise, just scan the read block for all 0s
* in the inner loop where the data copying is done.
* Note that some file systems such as NFSv3, NFSv4.0 and NFSv4.1 may
* support holes on the server, but do not support FIOSEEKHOLE.
* The kernel flag COPY_FILE_RANGE_TIMEO1SEC is used to indicate
* that this function should return after 1second with a partial
* completion.
*/
if ((flags & COPY_FILE_RANGE_TIMEO1SEC) != 0) {
getnanouptime(&endts);
endts.tv_sec++;
} else
timespecclear(&endts);
holetoeof = eof = false;
while (len > 0 && error == 0 && !eof && interrupted == 0) {
endoff = 0; /* To shut up compilers. */
cantseek = true;
startoff = *inoffp;
copylen = len;
/*
* Find the next data area. If there is just a hole to EOF,
* FIOSEEKDATA should fail with ENXIO.
* (I do not know if any file system will report a hole to
* EOF via FIOSEEKHOLE, but I am pretty sure FIOSEEKDATA
* will fail for those file systems.)
*
* For input files that don't support FIOSEEKDATA/FIOSEEKHOLE,
* the code just falls through to the inner copy loop.
*/
error = EINVAL;
if (holein > 0) {
error = VOP_IOCTL(invp, FIOSEEKDATA, &startoff, 0,
incred, curthread);
if (error == ENXIO) {
startoff = endoff = inva.va_size;
eof = holetoeof = true;
error = 0;
}
}
if (error == 0 && !holetoeof) {
endoff = startoff;
error = VOP_IOCTL(invp, FIOSEEKHOLE, &endoff, 0,
incred, curthread);
/*
* Since invp is unlocked, it may be possible for
* another thread to do a truncate(), lseek(), write()
* creating a hole at startoff between the above
* VOP_IOCTL() calls, if the other thread does not do
* rangelocking.
* If that happens, startoff == endoff and finding
* the hole has failed, so set an error.
*/
if (error == 0 && startoff == endoff)
error = EINVAL; /* Any error. Reset to 0. */
}
if (error == 0) {
if (startoff > *inoffp) {
/* Found hole before data block. */
xfer = MIN(startoff - *inoffp, len);
if (*outoffp < va.va_size) {
/* Must write 0s to punch hole. */
xfer2 = MIN(va.va_size - *outoffp,
xfer);
memset(dat, 0, MIN(xfer2, blksize));
error = vn_write_outvp(outvp, dat,
*outoffp, xfer2, blksize, false,
holeout > 0, outcred);
}
if (error == 0 && *outoffp + xfer >
va.va_size && (xfer == len || holetoeof)) {
/* Grow output file (hole at end). */
error = vn_write_outvp(outvp, dat,
*outoffp, xfer, blksize, true,
false, outcred);
}
if (error == 0) {
*inoffp += xfer;
*outoffp += xfer;
len -= xfer;
if (len < savlen) {
interrupted = sig_intr();
if (timespecisset(&endts) &&
interrupted == 0) {
getnanouptime(&curts);
if (timespeccmp(&curts,
&endts, >=))
interrupted =
EINTR;
}
}
}
}
copylen = MIN(len, endoff - startoff);
cantseek = false;
} else {
cantseek = true;
startoff = *inoffp;
copylen = len;
error = 0;
}
xfer = blksize;
if (cantseek) {
/*
* Set first xfer to end at a block boundary, so that
* holes are more likely detected in the loop below via
* the for all bytes 0 method.
*/
xfer -= (*inoffp % blksize);
}
/* Loop copying the data block. */
while (copylen > 0 && error == 0 && !eof && interrupted == 0) {
if (copylen < xfer)
xfer = copylen;
error = vn_lock(invp, LK_SHARED);
if (error != 0)
goto out;
error = vn_rdwr(UIO_READ, invp, dat, xfer,
startoff, UIO_SYSSPACE, IO_NODELOCKED,
curthread->td_ucred, incred, &aresid,
curthread);
VOP_UNLOCK(invp);
lastblock = false;
if (error == 0 && aresid > 0) {
/* Stop the copy at EOF on the input file. */
xfer -= aresid;
eof = true;
lastblock = true;
}
if (error == 0) {
/*
* Skip the write for holes past the initial EOF
* of the output file, unless this is the last
* write of the output file at EOF.
*/
readzeros = cantseek ? mem_iszero(dat, xfer) :
false;
if (xfer == len)
lastblock = true;
if (!cantseek || *outoffp < va.va_size ||
lastblock || !readzeros)
error = vn_write_outvp(outvp, dat,
*outoffp, xfer, blksize,
readzeros && lastblock &&
*outoffp >= va.va_size, false,
outcred);
if (error == 0) {
*inoffp += xfer;
startoff += xfer;
*outoffp += xfer;
copylen -= xfer;
len -= xfer;
if (len < savlen) {
interrupted = sig_intr();
if (timespecisset(&endts) &&
interrupted == 0) {
getnanouptime(&curts);
if (timespeccmp(&curts,
&endts, >=))
interrupted =
EINTR;
}
}
}
}
xfer = blksize;
}
}
out:
*lenp = savlen - len;
free(dat, M_TEMP);
return (error);
}
static int
vn_fallocate(struct file *fp, off_t offset, off_t len, struct thread *td)
{
struct mount *mp;
struct vnode *vp;
off_t olen, ooffset;
int error;
#ifdef AUDIT
int audited_vnode1 = 0;
#endif
vp = fp->f_vnode;
if (vp->v_type != VREG)
return (ENODEV);
/* Allocating blocks may take a long time, so iterate. */
for (;;) {
olen = len;
ooffset = offset;
bwillwrite();
mp = NULL;
error = vn_start_write(vp, &mp, V_WAIT | PCATCH);
if (error != 0)
break;
error = vn_lock(vp, LK_EXCLUSIVE);
if (error != 0) {
vn_finished_write(mp);
break;
}
#ifdef AUDIT
if (!audited_vnode1) {
AUDIT_ARG_VNODE1(vp);
audited_vnode1 = 1;
}
#endif
#ifdef MAC
error = mac_vnode_check_write(td->td_ucred, fp->f_cred, vp);
if (error == 0)
#endif
error = VOP_ALLOCATE(vp, &offset, &len, 0,
td->td_ucred);
VOP_UNLOCK(vp);
vn_finished_write(mp);
if (olen + ooffset != offset + len) {
panic("offset + len changed from %jx/%jx to %jx/%jx",
ooffset, olen, offset, len);
}
if (error != 0 || len == 0)
break;
KASSERT(olen > len, ("Iteration did not make progress?"));
maybe_yield();
}
return (error);
}
static int
vn_deallocate_impl(struct vnode *vp, off_t *offset, off_t *length, int flags,
int ioflag, struct ucred *cred, struct ucred *active_cred,
struct ucred *file_cred)
{
struct mount *mp;
void *rl_cookie;
off_t off, len;
int error;
#ifdef AUDIT
bool audited_vnode1 = false;
#endif
rl_cookie = NULL;
error = 0;
mp = NULL;
off = *offset;
len = *length;
if ((ioflag & (IO_NODELOCKED | IO_RANGELOCKED)) == 0)
rl_cookie = vn_rangelock_wlock(vp, off, off + len);
while (len > 0 && error == 0) {
/*
* Try to deallocate the longest range in one pass.
* In case a pass takes too long to be executed, it returns
* partial result. The residue will be proceeded in the next
* pass.
*/
if ((ioflag & IO_NODELOCKED) == 0) {
bwillwrite();
if ((error = vn_start_write(vp, &mp,
V_WAIT | PCATCH)) != 0)
goto out;
vn_lock(vp, vn_lktype_write(mp, vp) | LK_RETRY);
}
#ifdef AUDIT
if (!audited_vnode1) {
AUDIT_ARG_VNODE1(vp);
audited_vnode1 = true;
}
#endif
#ifdef MAC
if ((ioflag & IO_NOMACCHECK) == 0)
error = mac_vnode_check_write(active_cred, file_cred,
vp);
#endif
if (error == 0)
error = VOP_DEALLOCATE(vp, &off, &len, flags, ioflag,
cred);
if ((ioflag & IO_NODELOCKED) == 0) {
VOP_UNLOCK(vp);
if (mp != NULL) {
vn_finished_write(mp);
mp = NULL;
}
}
if (error == 0 && len != 0)
maybe_yield();
}
out:
if (rl_cookie != NULL)
vn_rangelock_unlock(vp, rl_cookie);
*offset = off;
*length = len;
return (error);
}
/*
* This function is supposed to be used in the situations where the deallocation
* is not triggered by a user request.
*/
int
vn_deallocate(struct vnode *vp, off_t *offset, off_t *length, int flags,
int ioflag, struct ucred *active_cred, struct ucred *file_cred)
{
struct ucred *cred;
if (*offset < 0 || *length <= 0 || *length > OFF_MAX - *offset ||
flags != 0)
return (EINVAL);
if (vp->v_type != VREG)
return (ENODEV);
cred = file_cred != NOCRED ? file_cred : active_cred;
return (vn_deallocate_impl(vp, offset, length, flags, ioflag, cred,
active_cred, file_cred));
}
static int
vn_fspacectl(struct file *fp, int cmd, off_t *offset, off_t *length, int flags,
struct ucred *active_cred, struct thread *td)
{
int error;
struct vnode *vp;
int ioflag;
vp = fp->f_vnode;
if (cmd != SPACECTL_DEALLOC || *offset < 0 || *length <= 0 ||
*length > OFF_MAX - *offset || flags != 0)
return (EINVAL);
if (vp->v_type != VREG)
return (ENODEV);
ioflag = get_write_ioflag(fp);
switch (cmd) {
case SPACECTL_DEALLOC:
error = vn_deallocate_impl(vp, offset, length, flags, ioflag,
active_cred, active_cred, fp->f_cred);
break;
default:
panic("vn_fspacectl: unknown cmd %d", cmd);
}
return (error);
}
static u_long vn_lock_pair_pause_cnt;
SYSCTL_ULONG(_debug, OID_AUTO, vn_lock_pair_pause, CTLFLAG_RD,
&vn_lock_pair_pause_cnt, 0,
"Count of vn_lock_pair deadlocks");
u_int vn_lock_pair_pause_max;
SYSCTL_UINT(_debug, OID_AUTO, vn_lock_pair_pause_max, CTLFLAG_RW,
&vn_lock_pair_pause_max, 0,
"Max ticks for vn_lock_pair deadlock avoidance sleep");
static void
vn_lock_pair_pause(const char *wmesg)
{
atomic_add_long(&vn_lock_pair_pause_cnt, 1);
pause(wmesg, prng32_bounded(vn_lock_pair_pause_max));
}
/*
* Lock pair of vnodes vp1, vp2, avoiding lock order reversal.
* vp1_locked indicates whether vp1 is exclusively locked; if not, vp1
* must be unlocked. Same for vp2 and vp2_locked. One of the vnodes
* can be NULL.
*
* The function returns with both vnodes exclusively locked, and
* guarantees that it does not create lock order reversal with other
* threads during its execution. Both vnodes could be unlocked
* temporary (and reclaimed).
*/
void
vn_lock_pair(struct vnode *vp1, bool vp1_locked, struct vnode *vp2,
bool vp2_locked)
{
int error;
if (vp1 == NULL && vp2 == NULL)
return;
if (vp1 != NULL) {
if (vp1_locked)
ASSERT_VOP_ELOCKED(vp1, "vp1");
else
ASSERT_VOP_UNLOCKED(vp1, "vp1");
} else {
vp1_locked = true;
}
if (vp2 != NULL) {
if (vp2_locked)
ASSERT_VOP_ELOCKED(vp2, "vp2");
else
ASSERT_VOP_UNLOCKED(vp2, "vp2");
} else {
vp2_locked = true;
}
if (!vp1_locked && !vp2_locked) {
vn_lock(vp1, LK_EXCLUSIVE | LK_RETRY);
vp1_locked = true;
}
for (;;) {
if (vp1_locked && vp2_locked)
break;
if (vp1_locked && vp2 != NULL) {
if (vp1 != NULL) {
error = VOP_LOCK1(vp2, LK_EXCLUSIVE | LK_NOWAIT,
__FILE__, __LINE__);
if (error == 0)
break;
VOP_UNLOCK(vp1);
vp1_locked = false;
vn_lock_pair_pause("vlp1");
}
vn_lock(vp2, LK_EXCLUSIVE | LK_RETRY);
vp2_locked = true;
}
if (vp2_locked && vp1 != NULL) {
if (vp2 != NULL) {
error = VOP_LOCK1(vp1, LK_EXCLUSIVE | LK_NOWAIT,
__FILE__, __LINE__);
if (error == 0)
break;
VOP_UNLOCK(vp2);
vp2_locked = false;
vn_lock_pair_pause("vlp2");
}
vn_lock(vp1, LK_EXCLUSIVE | LK_RETRY);
vp1_locked = true;
}
}
if (vp1 != NULL)
ASSERT_VOP_ELOCKED(vp1, "vp1 ret");
if (vp2 != NULL)
ASSERT_VOP_ELOCKED(vp2, "vp2 ret");
}
int
vn_lktype_write(struct mount *mp, struct vnode *vp)
{
if (MNT_SHARED_WRITES(mp) ||
(mp == NULL && MNT_SHARED_WRITES(vp->v_mount)))
return (LK_SHARED);
return (LK_EXCLUSIVE);
}
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