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3b1f974bfb
freebsd-skq/sys/kern/vfs_vnops.c
Konstantin Belousov 3b1f974bfb Make max ticks for pause in vn_lock_pair() adjustable at runtime. 
Reduce default value from hz / 10 to hz / 100.

Reviewed by:	markj
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
2020-11-26 18:00:26 +00:00

3422 lines
86 KiB
C
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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 <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_stat_t vn_statfile;
static fo_close_t vn_closefile;
static fo_mmap_t vn_mmap;
static fo_fallocate_t vn_fallocate;
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_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 = ndp->ni_cnd.cn_thread;
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_BENEATH) != 0)
res |= BENEATH;
if ((fmode & O_RESOLVE_BENEATH) != 0)
res |= RBENEATH;
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 thread *td = ndp->ni_cnd.cn_thread;
struct vattr vat;
struct vattr *vap = &vat;
int fmode, error;
restart:
fmode = *flagp;
if ((fmode & (O_CREAT | O_EXCL | O_DIRECTORY)) == (O_CREAT |
O_EXCL | O_DIRECTORY))
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.
*/
ndp->ni_cnd.cn_flags |= LOCKPARENT | NOCACHE;
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);
vput(ndp->ni_dvp);
vn_finished_write(mp);
if (error) {
NDFREE(ndp, NDF_ONLY_PNBUF);
if (error == ERELOOKUP) {
NDREINIT(ndp);
goto restart;
}
return (error);
}
fmode &= ~O_TRUNC;
vp = ndp->ni_vp;
} 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, td, fp);
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;
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);
if (error == 0 && VN_IS_DOOMED(vp))
error = ENOENT;
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)
return (EMLINK);
if (vp->v_type == VSOCK)
return (EOPNOTSUPP);
if (vp->v_type != VDIR && fmode & O_DIRECTORY)
return (ENOTDIR);
accmode = 0;
if (fmode & (FWRITE | O_TRUNC)) {
if (vp->v_type == VDIR)
return (EISDIR);
accmode |= VWRITE;
}
if (fmode & FREAD)
accmode |= VREAD;
if (fmode & FEXEC)
accmode |= VEXEC;
if ((fmode & O_APPEND) && (fmode & FWRITE))
accmode |= VAPPEND;
#ifdef MAC
if (fmode & O_CREAT)
accmode |= VCREAT;
if (fmode & O_VERIFY)
accmode |= VVERIFY;
error = mac_vnode_check_open(cred, vp, accmode);
if (error)
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 (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().
* Arrange for that by having fdrop() to use vn_closefile().
*/
if (error != 0) {
fp->f_flag |= FOPENFAILED;
fp->f_vnode = vp;
if (fp->f_ops == &badfileops) {
fp->f_type = DTYPE_VNODE;
fp->f_ops = &vnops;
}
vref(vp);
}
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 {
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;
if (MNT_SHARED_WRITES(mp) ||
((mp == NULL) && MNT_SHARED_WRITES(vp->v_mount)))
lock_flags = LK_SHARED;
else
lock_flags = LK_EXCLUSIVE;
} 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);
}
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;
obj = vp->v_object;
MPASS(uio->uio_resid <= ptoa(io_hold_cnt + 2));
MPASS(obj != NULL);
MPASS(obj->type == OBJT_VNODE);
/*
* 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 + 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() &&
(vp->v_irflag & (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, lock_flags;
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;
if (vp->v_type == VREG)
bwillwrite();
ioflag = IO_UNIT;
if (vp->v_type == VREG && (fp->f_flag & O_APPEND))
ioflag |= IO_APPEND;
if (fp->f_flag & FNONBLOCK)
ioflag |= IO_NDELAY;
if (fp->f_flag & O_DIRECT)
ioflag |= IO_DIRECT;
if ((fp->f_flag & O_FSYNC) ||
(vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS)))
ioflag |= IO_SYNC;
mp = NULL;
if (vp->v_type != VCHR &&
(error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) != 0)
goto unlock;
advice = get_advice(fp, uio);
if (MNT_SHARED_WRITES(mp) ||
(mp == NULL && MNT_SHARED_WRITES(vp->v_mount))) {
lock_flags = LK_SHARED;
} else {
lock_flags = LK_EXCLUSIVE;
}
vn_lock(vp, lock_flags | 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 (vp->v_type != VCHR)
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.
*/
static int
vn_statfile(struct file *fp, struct stat *sb, struct ucred *active_cred,
struct thread *td)
{
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, td);
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 && fp->f_type == DTYPE_VNODE;
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));
}
/*
* 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)
{
if (vp->v_type != VREG || td == NULL)
return (0);
if ((uoff_t)uio->uio_offset + uio->uio_resid >
lim_cur(td, RLIMIT_FSIZE)) {
PROC_LOCK(td->td_proc);
kern_psignal(td->td_proc, SIGXFSZ);
PROC_UNLOCK(td->td_proc);
return (EFBIG);
}
return (0);
}
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));
}
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);
}
int
vn_bmap_seekhole(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,
("Wrong command %lu", cmd));
if (vn_lock(vp, LK_SHARED) != 0)
return (EBADF);
if (vp->v_type != VREG) {
error = ENOTTY;
goto unlock;
}
error = VOP_GETATTR(vp, &va, cred);
if (error != 0)
goto unlock;
noff = *off;
if (noff >= va.va_size) {
error = ENXIO;
goto unlock;
}
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 unlock;
}
if ((bnp == -1 && cmd == FIOSEEKHOLE) ||
(bnp != -1 && cmd == FIOSEEKDATA)) {
noff = bn * bsize;
if (noff < *off)
noff = *off;
goto unlock;
}
}
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;
unlock:
VOP_UNLOCK(vp);
if (error == 0)
*off = noff;
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, lckf;
/*
* 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 {
if (MNT_SHARED_WRITES(mp))
lckf = LK_SHARED;
else
lckf = LK_EXCLUSIVE;
error = vn_lock(outvp, lckf);
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;
struct mount *mp;
struct uio io;
off_t startoff, endoff, xfer, xfer2;
u_long blksize;
int error, interrupted;
bool cantseek, readzeros, eof, lastblock;
ssize_t aresid;
size_t copylen, len, rem, savlen;
char *dat;
long holein, holeout;
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;
VOP_UNLOCK(invp);
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 > 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.
*/
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 and then we drop down into the
* inner loop and create the hole on the outvp file.
* (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 == 0) {
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)
/* Grow last block. */
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();
}
}
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();
}
}
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);
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 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");
}
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