freebsd-dev/sys/kern/vfs_vnops.c
Mike Pritchard 87aabdc126 Add a VNASSERT to vn_close to detect if v_writecount is going
to become negative.  This will detect the underflow when it
happens, instead of having it discovered when the vnode is
taken off the freelist, long after the offending process is long
gone.
2007-02-12 22:53:01 +00:00

1257 lines
28 KiB
C

/*-
* Copyright (c) 1982, 1986, 1989, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)vfs_vnops.c 8.2 (Berkeley) 1/21/94
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_mac.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/fcntl.h>
#include <sys/file.h>
#include <sys/kdb.h>
#include <sys/stat.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/limits.h>
#include <sys/lock.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/sx.h>
#include <sys/ttycom.h>
#include <sys/conf.h>
#include <sys/syslog.h>
#include <sys/unistd.h>
#include <security/mac/mac_framework.h>
static fo_rdwr_t vn_read;
static fo_rdwr_t vn_write;
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;
struct fileops vnops = {
.fo_read = vn_read,
.fo_write = vn_write,
.fo_ioctl = vn_ioctl,
.fo_poll = vn_poll,
.fo_kqfilter = vn_kqfilter,
.fo_stat = vn_statfile,
.fo_close = vn_closefile,
.fo_flags = DFLAG_PASSABLE | DFLAG_SEEKABLE
};
int
vn_open(ndp, flagp, cmode, fdidx)
struct nameidata *ndp;
int *flagp, cmode, fdidx;
{
struct thread *td = ndp->ni_cnd.cn_thread;
return (vn_open_cred(ndp, flagp, cmode, td->td_ucred, fdidx));
}
/*
* Common code for vnode open operations.
* 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(ndp, flagp, cmode, cred, fdidx)
struct nameidata *ndp;
int *flagp, cmode;
struct ucred *cred;
int fdidx;
{
struct vnode *vp;
struct mount *mp;
struct thread *td = ndp->ni_cnd.cn_thread;
struct vattr vat;
struct vattr *vap = &vat;
int mode, fmode, error;
int vfslocked, mpsafe;
mpsafe = ndp->ni_cnd.cn_flags & MPSAFE;
restart:
vfslocked = 0;
fmode = *flagp;
if (fmode & O_CREAT) {
ndp->ni_cnd.cn_nameiop = CREATE;
ndp->ni_cnd.cn_flags = ISOPEN | LOCKPARENT | LOCKLEAF |
MPSAFE | AUDITVNODE1;
if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0)
ndp->ni_cnd.cn_flags |= FOLLOW;
bwillwrite();
if ((error = namei(ndp)) != 0)
return (error);
vfslocked = NDHASGIANT(ndp);
if (!mpsafe)
ndp->ni_cnd.cn_flags &= ~MPSAFE;
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);
VFS_UNLOCK_GIANT(vfslocked);
if ((error = vn_start_write(NULL, &mp,
V_XSLEEP | PCATCH)) != 0)
return (error);
goto restart;
}
#ifdef MAC
error = mac_check_vnode_create(cred, ndp->ni_dvp,
&ndp->ni_cnd, vap);
if (error == 0) {
#endif
VOP_LEASE(ndp->ni_dvp, td, cred, LEASE_WRITE);
error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp,
&ndp->ni_cnd, vap);
#ifdef MAC
}
#endif
vput(ndp->ni_dvp);
vn_finished_write(mp);
if (error) {
VFS_UNLOCK_GIANT(vfslocked);
NDFREE(ndp, NDF_ONLY_PNBUF);
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;
}
fmode &= ~O_CREAT;
}
} else {
ndp->ni_cnd.cn_nameiop = LOOKUP;
ndp->ni_cnd.cn_flags = ISOPEN |
((fmode & O_NOFOLLOW) ? NOFOLLOW : FOLLOW) |
LOCKSHARED | LOCKLEAF | MPSAFE | AUDITVNODE1;
if ((error = namei(ndp)) != 0)
return (error);
if (!mpsafe)
ndp->ni_cnd.cn_flags &= ~MPSAFE;
vfslocked = NDHASGIANT(ndp);
vp = ndp->ni_vp;
}
if (vp->v_type == VLNK) {
error = EMLINK;
goto bad;
}
if (vp->v_type == VSOCK) {
error = EOPNOTSUPP;
goto bad;
}
mode = 0;
if (fmode & (FWRITE | O_TRUNC)) {
if (vp->v_type == VDIR) {
error = EISDIR;
goto bad;
}
mode |= VWRITE;
}
if (fmode & FREAD)
mode |= VREAD;
if (fmode & O_APPEND)
mode |= VAPPEND;
#ifdef MAC
error = mac_check_vnode_open(cred, vp, mode);
if (error)
goto bad;
#endif
if ((fmode & O_CREAT) == 0) {
if (mode & VWRITE) {
error = vn_writechk(vp);
if (error)
goto bad;
}
if (mode) {
error = VOP_ACCESS(vp, mode, cred, td);
if (error)
goto bad;
}
}
if ((error = VOP_OPEN(vp, fmode, cred, td, fdidx)) != 0)
goto bad;
if (fmode & FWRITE)
vp->v_writecount++;
*flagp = fmode;
ASSERT_VOP_LOCKED(vp, "vn_open_cred");
if (!mpsafe)
VFS_UNLOCK_GIANT(vfslocked);
return (0);
bad:
NDFREE(ndp, NDF_ONLY_PNBUF);
vput(vp);
VFS_UNLOCK_GIANT(vfslocked);
*flagp = fmode;
ndp->ni_vp = NULL;
return (error);
}
/*
* Check for write permissions on the specified vnode.
* Prototype text segments cannot be written.
*/
int
vn_writechk(vp)
register 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 (vp->v_vflag & VV_TEXT)
return (ETXTBSY);
return (0);
}
/*
* Vnode close call
*/
int
vn_close(vp, flags, file_cred, td)
register struct vnode *vp;
int flags;
struct ucred *file_cred;
struct thread *td;
{
struct mount *mp;
int error;
VFS_ASSERT_GIANT(vp->v_mount);
vn_start_write(vp, &mp, V_WAIT);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
if (flags & FWRITE) {
VNASSERT(vp->v_writecount > 0, vp,
("vn_close: negative writecount"));
vp->v_writecount--;
}
error = VOP_CLOSE(vp, flags, file_cred, td);
vput(vp);
vn_finished_write(mp);
return (error);
}
/*
* Sequential heuristic - detect sequential operation
*/
static __inline
int
sequential_heuristic(struct uio *uio, struct file *fp)
{
if ((uio->uio_offset == 0 && fp->f_seqcount > 0) ||
uio->uio_offset == fp->f_nextoff) {
/*
* XXX we assume that the filesystem block size is
* the default. Not true, but still gives us a pretty
* good indicator of how sequential the read operations
* are.
*/
fp->f_seqcount += (uio->uio_resid + BKVASIZE - 1) / BKVASIZE;
if (fp->f_seqcount > IO_SEQMAX)
fp->f_seqcount = IO_SEQMAX;
return(fp->f_seqcount << IO_SEQSHIFT);
}
/*
* Not sequential, quick draw-down of seqcount
*/
if (fp->f_seqcount > 1)
fp->f_seqcount = 1;
else
fp->f_seqcount = 0;
return(0);
}
/*
* Package up an I/O request on a vnode into a uio and do it.
*/
int
vn_rdwr(rw, vp, base, len, offset, segflg, ioflg, active_cred, file_cred,
aresid, td)
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;
int *aresid;
struct thread *td;
{
struct uio auio;
struct iovec aiov;
struct mount *mp;
struct ucred *cred;
int error;
VFS_ASSERT_GIANT(vp->v_mount);
if ((ioflg & IO_NODELOCKED) == 0) {
mp = NULL;
if (rw == UIO_WRITE) {
if (vp->v_type != VCHR &&
(error = vn_start_write(vp, &mp, V_WAIT | PCATCH))
!= 0)
return (error);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
} else {
/*
* XXX This should be LK_SHARED but I don't trust VFS
* enough to leave it like that until it has been
* reviewed further.
*/
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
}
}
ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
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;
#ifdef MAC
if ((ioflg & IO_NOMACCHECK) == 0) {
if (rw == UIO_READ)
error = mac_check_vnode_read(active_cred, file_cred,
vp);
else
error = mac_check_vnode_write(active_cred, file_cred,
vp);
}
#endif
if (error == 0) {
if (file_cred)
cred = file_cred;
else
cred = active_cred;
if (rw == UIO_READ)
error = VOP_READ(vp, &auio, ioflg, cred);
else
error = VOP_WRITE(vp, &auio, ioflg, cred);
}
if (aresid)
*aresid = auio.uio_resid;
else
if (auio.uio_resid && error == 0)
error = EIO;
if ((ioflg & IO_NODELOCKED) == 0) {
if (rw == UIO_WRITE && vp->v_type != VCHR)
vn_finished_write(mp);
VOP_UNLOCK(vp, 0, td);
}
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 uio_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(rw, vp, base, len, offset, segflg, ioflg, active_cred,
file_cred, aresid, td)
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;
int iaresid;
VFS_ASSERT_GIANT(vp->v_mount);
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;
uio_yield();
} while (len);
if (aresid)
*aresid = len + iaresid;
return (error);
}
/*
* File table vnode read routine.
*/
static int
vn_read(fp, uio, active_cred, flags, td)
struct file *fp;
struct uio *uio;
struct ucred *active_cred;
struct thread *td;
int flags;
{
struct vnode *vp;
int error, ioflag;
int vfslocked;
KASSERT(uio->uio_td == td, ("uio_td %p is not td %p",
uio->uio_td, td));
vp = fp->f_vnode;
ioflag = 0;
if (fp->f_flag & FNONBLOCK)
ioflag |= IO_NDELAY;
if (fp->f_flag & O_DIRECT)
ioflag |= IO_DIRECT;
vfslocked = VFS_LOCK_GIANT(vp->v_mount);
VOP_LEASE(vp, td, fp->f_cred, LEASE_READ);
/*
* According to McKusick the vn lock was protecting f_offset here.
* It is now protected by the FOFFSET_LOCKED flag.
*/
if ((flags & FOF_OFFSET) == 0) {
FILE_LOCK(fp);
while(fp->f_vnread_flags & FOFFSET_LOCKED) {
fp->f_vnread_flags |= FOFFSET_LOCK_WAITING;
msleep(&fp->f_vnread_flags,fp->f_mtxp,PUSER -1,"vnread offlock",0);
}
fp->f_vnread_flags |= FOFFSET_LOCKED;
FILE_UNLOCK(fp);
vn_lock(vp, LK_SHARED | LK_RETRY, td);
uio->uio_offset = fp->f_offset;
} else
vn_lock(vp, LK_SHARED | LK_RETRY, td);
ioflag |= sequential_heuristic(uio, fp);
#ifdef MAC
error = mac_check_vnode_read(active_cred, fp->f_cred, vp);
if (error == 0)
#endif
error = VOP_READ(vp, uio, ioflag, fp->f_cred);
if ((flags & FOF_OFFSET) == 0) {
fp->f_offset = uio->uio_offset;
FILE_LOCK(fp);
if (fp->f_vnread_flags & FOFFSET_LOCK_WAITING)
wakeup(&fp->f_vnread_flags);
fp->f_vnread_flags = 0;
FILE_UNLOCK(fp);
}
fp->f_nextoff = uio->uio_offset;
VOP_UNLOCK(vp, 0, td);
VFS_UNLOCK_GIANT(vfslocked);
return (error);
}
/*
* File table vnode write routine.
*/
static int
vn_write(fp, uio, active_cred, flags, td)
struct file *fp;
struct uio *uio;
struct ucred *active_cred;
struct thread *td;
int flags;
{
struct vnode *vp;
struct mount *mp;
int error, ioflag;
int vfslocked;
KASSERT(uio->uio_td == td, ("uio_td %p is not td %p",
uio->uio_td, td));
vp = fp->f_vnode;
vfslocked = VFS_LOCK_GIANT(vp->v_mount);
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;
VOP_LEASE(vp, td, fp->f_cred, LEASE_WRITE);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
if ((flags & FOF_OFFSET) == 0)
uio->uio_offset = fp->f_offset;
ioflag |= sequential_heuristic(uio, fp);
#ifdef MAC
error = mac_check_vnode_write(active_cred, fp->f_cred, vp);
if (error == 0)
#endif
error = VOP_WRITE(vp, uio, ioflag, fp->f_cred);
if ((flags & FOF_OFFSET) == 0)
fp->f_offset = uio->uio_offset;
fp->f_nextoff = uio->uio_offset;
VOP_UNLOCK(vp, 0, td);
if (vp->v_type != VCHR)
vn_finished_write(mp);
unlock:
VFS_UNLOCK_GIANT(vfslocked);
return (error);
}
/*
* File table vnode stat routine.
*/
static int
vn_statfile(fp, sb, active_cred, td)
struct file *fp;
struct stat *sb;
struct ucred *active_cred;
struct thread *td;
{
struct vnode *vp = fp->f_vnode;
int vfslocked;
int error;
vfslocked = VFS_LOCK_GIANT(vp->v_mount);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
error = vn_stat(vp, sb, active_cred, fp->f_cred, td);
VOP_UNLOCK(vp, 0, td);
VFS_UNLOCK_GIANT(vfslocked);
return (error);
}
/*
* Stat a vnode; implementation for the stat syscall
*/
int
vn_stat(vp, sb, active_cred, file_cred, td)
struct vnode *vp;
register struct stat *sb;
struct ucred *active_cred;
struct ucred *file_cred;
struct thread *td;
{
struct vattr vattr;
register struct vattr *vap;
int error;
u_short mode;
#ifdef MAC
error = mac_check_vnode_stat(active_cred, file_cred, vp);
if (error)
return (error);
#endif
vap = &vattr;
error = VOP_GETATTR(vp, vap, active_cred, td);
if (error)
return (error);
/*
* Zero the spare stat fields
*/
bzero(sb, sizeof *sb);
/*
* Copy from vattr table
*/
if (vap->va_fsid != VNOVAL)
sb->st_dev = vap->va_fsid;
else
sb->st_dev = vp->v_mount->mnt_stat.f_fsid.val[0];
sb->st_ino = vap->va_fileid;
mode = vap->va_mode;
switch (vap->va_type) {
case VREG:
mode |= S_IFREG;
break;
case VDIR:
mode |= S_IFDIR;
break;
case VBLK:
mode |= S_IFBLK;
break;
case VCHR:
mode |= S_IFCHR;
break;
case VLNK:
mode |= S_IFLNK;
/* This is a cosmetic change, symlinks do not have a mode. */
if (vp->v_mount->mnt_flag & MNT_NOSYMFOLLOW)
sb->st_mode &= ~ACCESSPERMS; /* 0000 */
else
sb->st_mode |= ACCESSPERMS; /* 0777 */
break;
case VSOCK:
mode |= S_IFSOCK;
break;
case VFIFO:
mode |= S_IFIFO;
break;
default:
return (EBADF);
};
sb->st_mode = mode;
sb->st_nlink = vap->va_nlink;
sb->st_uid = vap->va_uid;
sb->st_gid = vap->va_gid;
sb->st_rdev = vap->va_rdev;
if (vap->va_size > OFF_MAX)
return (EOVERFLOW);
sb->st_size = vap->va_size;
sb->st_atimespec = vap->va_atime;
sb->st_mtimespec = vap->va_mtime;
sb->st_ctimespec = vap->va_ctime;
sb->st_birthtimespec = vap->va_birthtime;
/*
* According to www.opengroup.org, the meaning of st_blksize is
* "a filesystem-specific preferred I/O block size for this
* object. In some filesystem types, this may vary from file
* to file"
* Default to PAGE_SIZE after much discussion.
* XXX: min(PAGE_SIZE, vp->v_bufobj.bo_bsize) may be more correct.
*/
sb->st_blksize = PAGE_SIZE;
sb->st_flags = vap->va_flags;
if (priv_check(td, PRIV_VFS_GENERATION))
sb->st_gen = 0;
else
sb->st_gen = vap->va_gen;
#if (S_BLKSIZE == 512)
/* Optimize this case */
sb->st_blocks = vap->va_bytes >> 9;
#else
sb->st_blocks = vap->va_bytes / S_BLKSIZE;
#endif
return (0);
}
/*
* File table vnode ioctl routine.
*/
static int
vn_ioctl(fp, com, data, active_cred, td)
struct file *fp;
u_long com;
void *data;
struct ucred *active_cred;
struct thread *td;
{
struct vnode *vp = fp->f_vnode;
struct vattr vattr;
int vfslocked;
int error;
vfslocked = VFS_LOCK_GIANT(vp->v_mount);
error = ENOTTY;
switch (vp->v_type) {
case VREG:
case VDIR:
if (com == FIONREAD) {
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
error = VOP_GETATTR(vp, &vattr, active_cred, td);
VOP_UNLOCK(vp, 0, td);
if (!error)
*(int *)data = vattr.va_size - fp->f_offset;
}
if (com == FIONBIO || com == FIOASYNC) /* XXX */
error = 0;
else
error = VOP_IOCTL(vp, com, data, fp->f_flag,
active_cred, td);
break;
default:
break;
}
VFS_UNLOCK_GIANT(vfslocked);
return (error);
}
/*
* File table vnode poll routine.
*/
static int
vn_poll(fp, events, active_cred, td)
struct file *fp;
int events;
struct ucred *active_cred;
struct thread *td;
{
struct vnode *vp;
int vfslocked;
int error;
vp = fp->f_vnode;
vfslocked = VFS_LOCK_GIANT(vp->v_mount);
#ifdef MAC
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
error = mac_check_vnode_poll(active_cred, fp->f_cred, vp);
VOP_UNLOCK(vp, 0, td);
if (!error)
#endif
error = VOP_POLL(vp, events, fp->f_cred, td);
VFS_UNLOCK_GIANT(vfslocked);
return (error);
}
/*
* Check that the vnode is still valid, and if so
* acquire requested lock.
*/
int
_vn_lock(struct vnode *vp, int flags, struct thread *td, char *file, int line)
{
int error;
do {
if ((flags & LK_INTERLOCK) == 0)
VI_LOCK(vp);
if ((flags & LK_NOWAIT || (flags & LK_TYPE_MASK) == 0) &&
vp->v_iflag & VI_DOOMED) {
VI_UNLOCK(vp);
return (ENOENT);
}
/*
* Just polling to check validity.
*/
if ((flags & LK_TYPE_MASK) == 0) {
VI_UNLOCK(vp);
return (0);
}
/*
* lockmgr drops interlock before it will return for
* any reason. So force the code above to relock it.
*/
error = _VOP_LOCK(vp, flags | LK_INTERLOCK, td, file, line);
flags &= ~LK_INTERLOCK;
KASSERT((flags & LK_RETRY) == 0 || error == 0,
("LK_RETRY set with incompatible flags %d\n", flags));
/*
* Callers specify LK_RETRY if they wish to get dead vnodes.
* If RETRY is not set, we return ENOENT instead.
*/
if (error == 0 && vp->v_iflag & VI_DOOMED &&
(flags & LK_RETRY) == 0) {
VOP_UNLOCK(vp, 0, td);
error = ENOENT;
break;
}
} while (flags & LK_RETRY && error != 0);
return (error);
}
/*
* File table vnode close routine.
*/
static int
vn_closefile(fp, td)
struct file *fp;
struct thread *td;
{
struct vnode *vp;
struct flock lf;
int vfslocked;
int error;
vp = fp->f_vnode;
vfslocked = VFS_LOCK_GIANT(vp->v_mount);
if (fp->f_type == DTYPE_VNODE && fp->f_flag & FHASLOCK) {
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);
}
fp->f_ops = &badfileops;
error = vn_close(vp, fp->f_flag, fp->f_cred, td);
VFS_UNLOCK_GIANT(vfslocked);
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.
*/
int
vn_start_write(vp, mpp, flags)
struct vnode *vp;
struct mount **mpp;
int flags;
{
struct mount *mp;
int error;
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);
MNT_ILOCK(mp);
if (vp == NULL)
MNT_REF(mp);
/*
* Check on status of suspension.
*/
while ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) {
if (flags & V_NOWAIT) {
error = EWOULDBLOCK;
goto unlock;
}
error = msleep(&mp->mnt_flag, MNT_MTX(mp),
(PUSER - 1) | (flags & PCATCH), "suspfs", 0);
if (error)
goto unlock;
}
if (flags & V_XSLEEP)
goto unlock;
mp->mnt_writeopcount++;
unlock:
MNT_REL(mp);
MNT_IUNLOCK(mp);
return (error);
}
/*
* 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_write_suspend_wait(vp, mp, flags)
struct vnode *vp;
struct mount *mp;
int flags;
{
int error;
if (vp != NULL) {
if ((error = VOP_GETWRITEMOUNT(vp, &mp)) != 0) {
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 == NULL)
return (0);
MNT_ILOCK(mp);
if (vp == NULL)
MNT_REF(mp);
if ((mp->mnt_kern_flag & MNTK_SUSPENDED) == 0) {
MNT_REL(mp);
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) | (flags & PCATCH) | PDROP, "suspfs", 0);
vfs_rel(mp);
return (error);
}
/*
* 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(vp, mpp, flags)
struct vnode *vp;
struct mount **mpp;
int flags;
{
struct mount *mp;
int error;
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);
MNT_ILOCK(mp);
if (vp == NULL)
MNT_REF(mp);
if ((mp->mnt_kern_flag & (MNTK_SUSPENDED | MNTK_SUSPEND2)) == 0) {
mp->mnt_secondary_writes++;
mp->mnt_secondary_accwrites++;
MNT_REL(mp);
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) | (flags & PCATCH) | PDROP, "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(mp)
struct mount *mp;
{
if (mp == NULL)
return;
MNT_ILOCK(mp);
mp->mnt_writeopcount--;
if (mp->mnt_writeopcount < 0)
panic("vn_finished_write: neg cnt");
if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 &&
mp->mnt_writeopcount <= 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(mp)
struct mount *mp;
{
if (mp == NULL)
return;
MNT_ILOCK(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(mp)
struct mount *mp;
{
struct thread *td = curthread;
int error;
MNT_ILOCK(mp);
if (mp->mnt_kern_flag & MNTK_SUSPEND) {
MNT_IUNLOCK(mp);
return (0);
}
mp->mnt_kern_flag |= MNTK_SUSPEND;
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, td)) != 0)
vfs_write_resume(mp);
return (error);
}
/*
* Request a filesystem to resume write operations.
*/
void
vfs_write_resume(mp)
struct mount *mp;
{
MNT_ILOCK(mp);
if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) {
mp->mnt_kern_flag &= ~(MNTK_SUSPEND | MNTK_SUSPEND2 |
MNTK_SUSPENDED);
wakeup(&mp->mnt_writeopcount);
wakeup(&mp->mnt_flag);
}
MNT_IUNLOCK(mp);
}
/*
* Implement kqueues for files by translating it to vnode operation.
*/
static int
vn_kqfilter(struct file *fp, struct knote *kn)
{
int vfslocked;
int error;
vfslocked = VFS_LOCK_GIANT(fp->f_vnode->v_mount);
error = VOP_KQFILTER(fp->f_vnode, kn);
VFS_UNLOCK_GIANT(vfslocked);
return error;
}
/*
* 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_EXCLUSIVE | LK_RETRY, td);
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, 0, td);
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, td);
}
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, 0, td);
}
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, td);
}
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, 0, td);
}
return (error);
}