d/freebsd-nq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
06ae1e91c4
freebsd-nq/sys/kern/vfs_vnops.c
Matthew Dillon 06ae1e91c4 This brings in a Yahoo coredump patch from Paul, with additional mods by 
me (addition of vn_rdwr_inchunks).  The problem Yahoo is solving is that
if you have large process images core dumping, or you have a large number of
forked processes all core dumping at the same time, the original coredump code
would leave the vnode locked throughout.  This can cause the directory vnode
to get locked up, which can cause the parent directory vnode to get locked
up, and so on all the way to the root node, locking the entire machine up
for extremely long periods of time.

This patch solves the problem in two ways.  First it uses an advisory
non-blocking lock to abort multiple processes trying to core to the same
file.  Second (my contribution) it chunks up the writes and uses bwillwrite()
to avoid holding the vnode locked while blocking in the buffer cache.

Submitted by:	ps
Reviewed by:	dillon
MFC after:	2 weeks
2001-09-08 20:02:33 +00:00

964 lines
22 KiB
C
Raw Blame History

/*
* Copyright (c) 1982, 1986, 1989, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 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
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/fcntl.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/proc.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/ttycom.h>
#include <sys/conf.h>
#include <machine/limits.h>
static int vn_closefile __P((struct file *fp, struct proc *p));
static int vn_ioctl __P((struct file *fp, u_long com, caddr_t data,
struct proc *p));
static int vn_read __P((struct file *fp, struct uio *uio,
struct ucred *cred, int flags, struct proc *p));
static int vn_poll __P((struct file *fp, int events, struct ucred *cred,
struct proc *p));
static int vn_kqfilter __P((struct file *fp, struct knote *kn));
static int vn_statfile __P((struct file *fp, struct stat *sb, struct proc *p));
static int vn_write __P((struct file *fp, struct uio *uio,
struct ucred *cred, int flags, struct proc *p));
struct fileops vnops = {
vn_read, vn_write, vn_ioctl, vn_poll, vn_kqfilter,
vn_statfile, vn_closefile
};
/*
* 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(ndp, flagp, cmode)
register struct nameidata *ndp;
int *flagp, cmode;
{
struct vnode *vp;
struct mount *mp;
struct proc *p = ndp->ni_cnd.cn_proc;
struct ucred *cred = p->p_ucred;
struct vattr vat;
struct vattr *vap = &vat;
int mode, fmode, error;
restart:
fmode = *flagp;
if (fmode & O_CREAT) {
ndp->ni_cnd.cn_nameiop = CREATE;
ndp->ni_cnd.cn_flags = LOCKPARENT | LOCKLEAF;
if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0)
ndp->ni_cnd.cn_flags |= FOLLOW;
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);
goto restart;
}
VOP_LEASE(ndp->ni_dvp, p, cred, LEASE_WRITE);
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);
return (error);
}
ASSERT_VOP_UNLOCKED(ndp->ni_dvp, "create");
ASSERT_VOP_LOCKED(ndp->ni_vp, "create");
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 =
((fmode & O_NOFOLLOW) ? NOFOLLOW : FOLLOW) | LOCKLEAF;
if ((error = namei(ndp)) != 0)
return (error);
vp = ndp->ni_vp;
}
if (vp->v_type == VLNK) {
error = EMLINK;
goto bad;
}
if (vp->v_type == VSOCK) {
error = EOPNOTSUPP;
goto bad;
}
if ((fmode & O_CREAT) == 0) {
mode = 0;
if (fmode & (FWRITE | O_TRUNC)) {
if (vp->v_type == VDIR) {
error = EISDIR;
goto bad;
}
error = vn_writechk(vp);
if (error)
goto bad;
mode |= VWRITE;
}
if (fmode & FREAD)
mode |= VREAD;
if (mode) {
error = VOP_ACCESS(vp, mode, cred, p);
if (error)
goto bad;
}
}
if ((error = VOP_OPEN(vp, fmode, cred, p)) != 0)
goto bad;
/*
* Make sure that a VM object is created for VMIO support.
*/
if (vn_canvmio(vp) == TRUE) {
if ((error = vfs_object_create(vp, p, cred)) != 0)
goto bad;
}
if (fmode & FWRITE)
vp->v_writecount++;
*flagp = fmode;
return (0);
bad:
NDFREE(ndp, NDF_ONLY_PNBUF);
vput(vp);
*flagp = fmode;
return (error);
}
/*
* Check for write permissions on the specified vnode.
* Prototype text segments cannot be written.
*/
int
vn_writechk(vp)
register struct vnode *vp;
{
/*
* 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_flag & VTEXT)
return (ETXTBSY);
return (0);
}
/*
* Vnode close call
*/
int
vn_close(vp, flags, cred, p)
register struct vnode *vp;
int flags;
struct ucred *cred;
struct proc *p;
{
int error;
if (flags & FWRITE)
vp->v_writecount--;
error = VOP_CLOSE(vp, flags, cred, p);
/*
* XXX - In certain instances VOP_CLOSE has to do the vrele
* itself. If the vrele has been done, it will return EAGAIN
* to indicate that the vrele should not be done again. When
* this happens, we just return success. The correct thing to
* do would be to have all VOP_CLOSE instances do the vrele.
*/
if (error == EAGAIN)
return (0);
vrele(vp);
return (error);
}
static __inline
int
sequential_heuristic(struct uio *uio, struct file *fp)
{
/*
* Sequential heuristic - detect sequential operation
*/
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 >= 127)
fp->f_seqcount = 127;
return(fp->f_seqcount << 16);
}
/*
* 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, cred, aresid, p)
enum uio_rw rw;
struct vnode *vp;
caddr_t base;
int len;
off_t offset;
enum uio_seg segflg;
int ioflg;
struct ucred *cred;
int *aresid;
struct proc *p;
{
struct uio auio;
struct iovec aiov;
struct mount *mp;
int error;
if ((ioflg & IO_NODELOCKED) == 0) {
mp = NULL;
if (rw == UIO_WRITE &&
vp->v_type != VCHR &&
(error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) != 0)
return (error);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
}
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
aiov.iov_base = base;
aiov.iov_len = len;
auio.uio_resid = len;
auio.uio_offset = offset;
auio.uio_segflg = segflg;
auio.uio_rw = rw;
auio.uio_procp = p;
if (rw == UIO_READ) {
error = VOP_READ(vp, &auio, ioflg, cred);
} else {
error = VOP_WRITE(vp, &auio, ioflg, cred);
}
if (aresid)
*aresid = auio.uio_resid;
else
if (auio.uio_resid && error == 0)
error = EIO;
if ((ioflg & IO_NODELOCKED) == 0) {
vn_finished_write(mp);
VOP_UNLOCK(vp, 0, p);
}
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()
*/
int
vn_rdwr_inchunks(rw, vp, base, len, offset, segflg, ioflg, cred, aresid, p)
enum uio_rw rw;
struct vnode *vp;
caddr_t base;
int len;
off_t offset;
enum uio_seg segflg;
int ioflg;
struct ucred *cred;
int *aresid;
struct proc *p;
{
int error = 0;
do {
int chunk = (len > MAXBSIZE) ? MAXBSIZE : len;
if (rw != UIO_READ && vp->v_type == VREG)
bwillwrite();
error = vn_rdwr(rw, vp, base, chunk, offset, segflg,
ioflg, cred, aresid, p);
len -= chunk; /* aresid calc already includes length */
if (error)
break;
offset += chunk;
base += chunk;
} while (len);
if (aresid)
*aresid += len;
return (error);
}
/*
* File table vnode read routine.
*/
static int
vn_read(fp, uio, cred, flags, p)
struct file *fp;
struct uio *uio;
struct ucred *cred;
struct proc *p;
int flags;
{
struct vnode *vp;
int error, ioflag;
KASSERT(uio->uio_procp == p, ("uio_procp %p is not p %p",
uio->uio_procp, p));
vp = (struct vnode *)fp->f_data;
ioflag = 0;
if (fp->f_flag & FNONBLOCK)
ioflag |= IO_NDELAY;
if (fp->f_flag & O_DIRECT)
ioflag |= IO_DIRECT;
VOP_LEASE(vp, p, cred, LEASE_READ);
vn_lock(vp, LK_SHARED | LK_NOPAUSE | LK_RETRY, p);
if ((flags & FOF_OFFSET) == 0)
uio->uio_offset = fp->f_offset;
ioflag |= sequential_heuristic(uio, fp);
error = VOP_READ(vp, uio, ioflag, cred);
if ((flags & FOF_OFFSET) == 0)
fp->f_offset = uio->uio_offset;
fp->f_nextoff = uio->uio_offset;
VOP_UNLOCK(vp, 0, p);
return (error);
}
/*
* File table vnode write routine.
*/
static int
vn_write(fp, uio, cred, flags, p)
struct file *fp;
struct uio *uio;
struct ucred *cred;
struct proc *p;
int flags;
{
struct vnode *vp;
struct mount *mp;
int error, ioflag;
KASSERT(uio->uio_procp == p, ("uio_procp %p is not p %p",
uio->uio_procp, p));
vp = (struct vnode *)fp->f_data;
if (vp->v_type == VREG)
bwillwrite();
vp = (struct vnode *)fp->f_data; /* XXX needed? */
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)
return (error);
VOP_LEASE(vp, p, cred, LEASE_WRITE);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
if ((flags & FOF_OFFSET) == 0)
uio->uio_offset = fp->f_offset;
ioflag |= sequential_heuristic(uio, fp);
error = VOP_WRITE(vp, uio, ioflag, cred);
if ((flags & FOF_OFFSET) == 0)
fp->f_offset = uio->uio_offset;
fp->f_nextoff = uio->uio_offset;
VOP_UNLOCK(vp, 0, p);
vn_finished_write(mp);
return (error);
}
/*
* File table vnode stat routine.
*/
static int
vn_statfile(fp, sb, p)
struct file *fp;
struct stat *sb;
struct proc *p;
{
struct vnode *vp = (struct vnode *)fp->f_data;
return vn_stat(vp, sb, p);
}
int
vn_stat(vp, sb, p)
struct vnode *vp;
register struct stat *sb;
struct proc *p;
{
struct vattr vattr;
register struct vattr *vap;
int error;
u_short mode;
vap = &vattr;
error = VOP_GETATTR(vp, vap, p->p_ucred, p);
if (error)
return (error);
/*
* Zero the spare stat fields
*/
sb->st_lspare = 0;
sb->st_qspare[0] = 0;
sb->st_qspare[1] = 0;
/*
* 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;
/*
* 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 zero to catch bogus uses of this field.
*/
if (vap->va_type == VREG) {
sb->st_blksize = vap->va_blocksize;
} else if (vn_isdisk(vp, NULL)) {
sb->st_blksize = vp->v_rdev->si_bsize_best;
if (sb->st_blksize < vp->v_rdev->si_bsize_phys)
sb->st_blksize = vp->v_rdev->si_bsize_phys;
if (sb->st_blksize < BLKDEV_IOSIZE)
sb->st_blksize = BLKDEV_IOSIZE;
} else {
sb->st_blksize = 0;
}
sb->st_flags = vap->va_flags;
if (suser_xxx(p->p_ucred, 0, 0))
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, p)
struct file *fp;
u_long com;
caddr_t data;
struct proc *p;
{
register struct vnode *vp = ((struct vnode *)fp->f_data);
struct vattr vattr;
int error;
switch (vp->v_type) {
case VREG:
case VDIR:
if (com == FIONREAD) {
error = VOP_GETATTR(vp, &vattr, p->p_ucred, p);
if (error)
return (error);
*(int *)data = vattr.va_size - fp->f_offset;
return (0);
}
if (com == FIONBIO || com == FIOASYNC) /* XXX */
return (0); /* XXX */
/* fall into ... */
default:
#if 0
return (ENOTTY);
#endif
case VFIFO:
case VCHR:
case VBLK:
if (com == FIODTYPE) {
if (vp->v_type != VCHR && vp->v_type != VBLK)
return (ENOTTY);
*(int *)data = devsw(vp->v_rdev)->d_flags & D_TYPEMASK;
return (0);
}
error = VOP_IOCTL(vp, com, data, fp->f_flag, p->p_ucred, p);
if (error == 0 && com == TIOCSCTTY) {
/* Do nothing if reassigning same control tty */
if (p->p_session->s_ttyvp == vp)
return (0);
/* Get rid of reference to old control tty */
if (p->p_session->s_ttyvp)
vrele(p->p_session->s_ttyvp);
p->p_session->s_ttyvp = vp;
VREF(vp);
}
return (error);
}
}
/*
* File table vnode poll routine.
*/
static int
vn_poll(fp, events, cred, p)
struct file *fp;
int events;
struct ucred *cred;
struct proc *p;
{
return (VOP_POLL(((struct vnode *)fp->f_data), events, cred, p));
}
/*
* Check that the vnode is still valid, and if so
* acquire requested lock.
*/
int
#ifndef DEBUG_LOCKS
vn_lock(vp, flags, p)
#else
debug_vn_lock(vp, flags, p, filename, line)
#endif
struct vnode *vp;
int flags;
struct proc *p;
#ifdef DEBUG_LOCKS
const char *filename;
int line;
#endif
{
int error;
do {
if ((flags & LK_INTERLOCK) == 0)
mtx_lock(&vp->v_interlock);
if ((vp->v_flag & VXLOCK) && vp->v_vxproc != curproc) {
vp->v_flag |= VXWANT;
msleep(vp, &vp->v_interlock, PINOD | PDROP,
"vn_lock", 0);
error = ENOENT;
} else {
if (vp->v_vxproc != NULL)
printf("VXLOCK interlock avoided in vn_lock\n");
#ifdef DEBUG_LOCKS
vp->filename = filename;
vp->line = line;
#endif
error = VOP_LOCK(vp,
flags | LK_NOPAUSE | LK_INTERLOCK, p);
if (error == 0)
return (error);
}
flags &= ~LK_INTERLOCK;
} while (flags & LK_RETRY);
return (error);
}
/*
* File table vnode close routine.
*/
static int
vn_closefile(fp, p)
struct file *fp;
struct proc *p;
{
fp->f_ops = &badfileops;
return (vn_close(((struct vnode *)fp->f_data), fp->f_flag,
fp->f_cred, p));
}
/*
* 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;
/*
* 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);
/*
* Check on status of suspension.
*/
while ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) {
if (flags & V_NOWAIT)
return (EWOULDBLOCK);
error = tsleep(&mp->mnt_flag, (PUSER - 1) | (flags & PCATCH),
"suspfs", 0);
if (error)
return (error);
}
if (flags & V_XSLEEP)
return (0);
mp->mnt_writeopcount++;
return (0);
}
/*
* 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 || (mp->mnt_kern_flag & MNTK_SUSPENDED) == 0)
return (0);
if (flags & V_NOWAIT)
return (EWOULDBLOCK);
/*
* Wait for the suspension to finish.
*/
return (tsleep(&mp->mnt_flag, (PUSER - 1) | (flags & PCATCH),
"suspfs", 0));
}
/*
* 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;
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);
}
/*
* Request a filesystem to suspend write operations.
*/
void
vfs_write_suspend(mp)
struct mount *mp;
{
struct proc *p = curproc;
if (mp->mnt_kern_flag & MNTK_SUSPEND)
return;
mp->mnt_kern_flag |= MNTK_SUSPEND;
if (mp->mnt_writeopcount > 0)
(void) tsleep(&mp->mnt_writeopcount, PUSER - 1, "suspwt", 0);
VFS_SYNC(mp, MNT_WAIT, p->p_ucred, p);
mp->mnt_kern_flag |= MNTK_SUSPENDED;
}
/*
* Request a filesystem to resume write operations.
*/
void
vfs_write_resume(mp)
struct mount *mp;
{
if ((mp->mnt_kern_flag & MNTK_SUSPEND) == 0)
return;
mp->mnt_kern_flag &= ~(MNTK_SUSPEND | MNTK_SUSPENDED);
wakeup(&mp->mnt_writeopcount);
wakeup(&mp->mnt_flag);
}
static int
vn_kqfilter(struct file *fp, struct knote *kn)
{
return (VOP_KQFILTER(((struct vnode *)fp->f_data), 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 proc *p)
{
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_procp = p;
auio.uio_offset = 0;
auio.uio_resid = *buflen;
if ((ioflg & IO_NODELOCKED) == 0)
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
/* authorize attribute retrieval as kernel */
error = VOP_GETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, p);
if ((ioflg & IO_NODELOCKED) == 0)
VOP_UNLOCK(vp, 0, p);
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 proc *p)
{
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_procp = p;
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, p);
}
/* authorize attribute setting as kernel */
error = VOP_SETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, p);
if ((ioflg & IO_NODELOCKED) == 0) {
vn_finished_write(mp);
VOP_UNLOCK(vp, 0, p);
}
return (error);
}
int
vn_extattr_rm(struct vnode *vp, int ioflg, int attrnamespace,
const char *attrname, struct proc *p)
{
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, p);
}
/* authorize attribute removal as kernel */
error = VOP_SETEXTATTR(vp, attrnamespace, attrname, NULL, NULL, p);
if ((ioflg & IO_NODELOCKED) == 0) {
vn_finished_write(mp);
VOP_UNLOCK(vp, 0, p);
}
return (error);
}
Reference in New Issue View Git Blame Copy Permalink