freebsd-dev/sys/kern/vfs_default.c
Matthew D Fleming 1ce4508f6d Allow VOP_ALLOCATE to be iterative, and have kern_posix_fallocate(9)
drive looping and potentially yielding.

Requested by:	kib
2011-04-19 16:36:24 +00:00

1134 lines
23 KiB
C

/*-
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed
* to Berkeley by John Heidemann of the UCLA Ficus project.
*
* Source: * @(#)i405_init.c 2.10 92/04/27 UCLA Ficus project
*
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/conf.h>
#include <sys/event.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/lockf.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/mutex.h>
#include <sys/namei.h>
#include <sys/fcntl.h>
#include <sys/unistd.h>
#include <sys/vnode.h>
#include <sys/dirent.h>
#include <sys/poll.h>
#include <security/mac/mac_framework.h>
#include <vm/vm.h>
#include <vm/vm_object.h>
#include <vm/vm_extern.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>
#include <vm/vnode_pager.h>
static int vop_nolookup(struct vop_lookup_args *);
static int vop_norename(struct vop_rename_args *);
static int vop_nostrategy(struct vop_strategy_args *);
static int get_next_dirent(struct vnode *vp, struct dirent **dpp,
char *dirbuf, int dirbuflen, off_t *off,
char **cpos, int *len, int *eofflag,
struct thread *td);
static int dirent_exists(struct vnode *vp, const char *dirname,
struct thread *td);
#define DIRENT_MINSIZE (sizeof(struct dirent) - (MAXNAMLEN+1) + 4)
/*
* This vnode table stores what we want to do if the filesystem doesn't
* implement a particular VOP.
*
* If there is no specific entry here, we will return EOPNOTSUPP.
*
* Note that every filesystem has to implement either vop_access
* or vop_accessx; failing to do so will result in immediate crash
* due to stack overflow, as vop_stdaccess() calls vop_stdaccessx(),
* which calls vop_stdaccess() etc.
*/
struct vop_vector default_vnodeops = {
.vop_default = NULL,
.vop_bypass = VOP_EOPNOTSUPP,
.vop_access = vop_stdaccess,
.vop_accessx = vop_stdaccessx,
.vop_advlock = vop_stdadvlock,
.vop_advlockasync = vop_stdadvlockasync,
.vop_advlockpurge = vop_stdadvlockpurge,
.vop_allocate = vop_stdallocate,
.vop_bmap = vop_stdbmap,
.vop_close = VOP_NULL,
.vop_fsync = VOP_NULL,
.vop_getpages = vop_stdgetpages,
.vop_getwritemount = vop_stdgetwritemount,
.vop_inactive = VOP_NULL,
.vop_ioctl = VOP_ENOTTY,
.vop_kqfilter = vop_stdkqfilter,
.vop_islocked = vop_stdislocked,
.vop_lock1 = vop_stdlock,
.vop_lookup = vop_nolookup,
.vop_open = VOP_NULL,
.vop_pathconf = VOP_EINVAL,
.vop_poll = vop_nopoll,
.vop_putpages = vop_stdputpages,
.vop_readlink = VOP_EINVAL,
.vop_rename = vop_norename,
.vop_revoke = VOP_PANIC,
.vop_strategy = vop_nostrategy,
.vop_unlock = vop_stdunlock,
.vop_vptocnp = vop_stdvptocnp,
.vop_vptofh = vop_stdvptofh,
};
/*
* Series of placeholder functions for various error returns for
* VOPs.
*/
int
vop_eopnotsupp(struct vop_generic_args *ap)
{
/*
printf("vop_notsupp[%s]\n", ap->a_desc->vdesc_name);
*/
return (EOPNOTSUPP);
}
int
vop_ebadf(struct vop_generic_args *ap)
{
return (EBADF);
}
int
vop_enotty(struct vop_generic_args *ap)
{
return (ENOTTY);
}
int
vop_einval(struct vop_generic_args *ap)
{
return (EINVAL);
}
int
vop_enoent(struct vop_generic_args *ap)
{
return (ENOENT);
}
int
vop_null(struct vop_generic_args *ap)
{
return (0);
}
/*
* Helper function to panic on some bad VOPs in some filesystems.
*/
int
vop_panic(struct vop_generic_args *ap)
{
panic("filesystem goof: vop_panic[%s]", ap->a_desc->vdesc_name);
}
/*
* vop_std<something> and vop_no<something> are default functions for use by
* filesystems that need the "default reasonable" implementation for a
* particular operation.
*
* The documentation for the operations they implement exists (if it exists)
* in the VOP_<SOMETHING>(9) manpage (all uppercase).
*/
/*
* Default vop for filesystems that do not support name lookup
*/
static int
vop_nolookup(ap)
struct vop_lookup_args /* {
struct vnode *a_dvp;
struct vnode **a_vpp;
struct componentname *a_cnp;
} */ *ap;
{
*ap->a_vpp = NULL;
return (ENOTDIR);
}
/*
* vop_norename:
*
* Handle unlock and reference counting for arguments of vop_rename
* for filesystems that do not implement rename operation.
*/
static int
vop_norename(struct vop_rename_args *ap)
{
vop_rename_fail(ap);
return (EOPNOTSUPP);
}
/*
* vop_nostrategy:
*
* Strategy routine for VFS devices that have none.
*
* BIO_ERROR and B_INVAL must be cleared prior to calling any strategy
* routine. Typically this is done for a BIO_READ strategy call.
* Typically B_INVAL is assumed to already be clear prior to a write
* and should not be cleared manually unless you just made the buffer
* invalid. BIO_ERROR should be cleared either way.
*/
static int
vop_nostrategy (struct vop_strategy_args *ap)
{
printf("No strategy for buffer at %p\n", ap->a_bp);
vprint("vnode", ap->a_vp);
ap->a_bp->b_ioflags |= BIO_ERROR;
ap->a_bp->b_error = EOPNOTSUPP;
bufdone(ap->a_bp);
return (EOPNOTSUPP);
}
static int
get_next_dirent(struct vnode *vp, struct dirent **dpp, char *dirbuf,
int dirbuflen, off_t *off, char **cpos, int *len,
int *eofflag, struct thread *td)
{
int error, reclen;
struct uio uio;
struct iovec iov;
struct dirent *dp;
KASSERT(VOP_ISLOCKED(vp), ("vp %p is not locked", vp));
KASSERT(vp->v_type == VDIR, ("vp %p is not a directory", vp));
if (*len == 0) {
iov.iov_base = dirbuf;
iov.iov_len = dirbuflen;
uio.uio_iov = &iov;
uio.uio_iovcnt = 1;
uio.uio_offset = *off;
uio.uio_resid = dirbuflen;
uio.uio_segflg = UIO_SYSSPACE;
uio.uio_rw = UIO_READ;
uio.uio_td = td;
*eofflag = 0;
#ifdef MAC
error = mac_vnode_check_readdir(td->td_ucred, vp);
if (error == 0)
#endif
error = VOP_READDIR(vp, &uio, td->td_ucred, eofflag,
NULL, NULL);
if (error)
return (error);
*off = uio.uio_offset;
*cpos = dirbuf;
*len = (dirbuflen - uio.uio_resid);
if (*len == 0)
return (ENOENT);
}
dp = (struct dirent *)(*cpos);
reclen = dp->d_reclen;
*dpp = dp;
/* check for malformed directory.. */
if (reclen < DIRENT_MINSIZE)
return (EINVAL);
*cpos += reclen;
*len -= reclen;
return (0);
}
/*
* Check if a named file exists in a given directory vnode.
*/
static int
dirent_exists(struct vnode *vp, const char *dirname, struct thread *td)
{
char *dirbuf, *cpos;
int error, eofflag, dirbuflen, len, found;
off_t off;
struct dirent *dp;
struct vattr va;
KASSERT(VOP_ISLOCKED(vp), ("vp %p is not locked", vp));
KASSERT(vp->v_type == VDIR, ("vp %p is not a directory", vp));
found = 0;
error = VOP_GETATTR(vp, &va, td->td_ucred);
if (error)
return (found);
dirbuflen = DEV_BSIZE;
if (dirbuflen < va.va_blocksize)
dirbuflen = va.va_blocksize;
dirbuf = (char *)malloc(dirbuflen, M_TEMP, M_WAITOK);
off = 0;
len = 0;
do {
error = get_next_dirent(vp, &dp, dirbuf, dirbuflen, &off,
&cpos, &len, &eofflag, td);
if (error)
goto out;
if ((dp->d_type != DT_WHT) &&
!strcmp(dp->d_name, dirname)) {
found = 1;
goto out;
}
} while (len > 0 || !eofflag);
out:
free(dirbuf, M_TEMP);
return (found);
}
int
vop_stdaccess(struct vop_access_args *ap)
{
KASSERT((ap->a_accmode & ~(VEXEC | VWRITE | VREAD | VADMIN |
VAPPEND)) == 0, ("invalid bit in accmode"));
return (VOP_ACCESSX(ap->a_vp, ap->a_accmode, ap->a_cred, ap->a_td));
}
int
vop_stdaccessx(struct vop_accessx_args *ap)
{
int error;
accmode_t accmode = ap->a_accmode;
error = vfs_unixify_accmode(&accmode);
if (error != 0)
return (error);
if (accmode == 0)
return (0);
return (VOP_ACCESS(ap->a_vp, accmode, ap->a_cred, ap->a_td));
}
/*
* Advisory record locking support
*/
int
vop_stdadvlock(struct vop_advlock_args *ap)
{
struct vnode *vp;
struct ucred *cred;
struct vattr vattr;
int error;
vp = ap->a_vp;
cred = curthread->td_ucred;
vn_lock(vp, LK_SHARED | LK_RETRY);
error = VOP_GETATTR(vp, &vattr, cred);
VOP_UNLOCK(vp, 0);
if (error)
return (error);
return (lf_advlock(ap, &(vp->v_lockf), vattr.va_size));
}
int
vop_stdadvlockasync(struct vop_advlockasync_args *ap)
{
struct vnode *vp;
struct ucred *cred;
struct vattr vattr;
int error;
vp = ap->a_vp;
cred = curthread->td_ucred;
vn_lock(vp, LK_SHARED | LK_RETRY);
error = VOP_GETATTR(vp, &vattr, cred);
VOP_UNLOCK(vp, 0);
if (error)
return (error);
return (lf_advlockasync(ap, &(vp->v_lockf), vattr.va_size));
}
int
vop_stdadvlockpurge(struct vop_advlockpurge_args *ap)
{
struct vnode *vp;
vp = ap->a_vp;
lf_purgelocks(vp, &vp->v_lockf);
return (0);
}
/*
* vop_stdpathconf:
*
* Standard implementation of POSIX pathconf, to get information about limits
* for a filesystem.
* Override per filesystem for the case where the filesystem has smaller
* limits.
*/
int
vop_stdpathconf(ap)
struct vop_pathconf_args /* {
struct vnode *a_vp;
int a_name;
int *a_retval;
} */ *ap;
{
switch (ap->a_name) {
case _PC_NAME_MAX:
*ap->a_retval = NAME_MAX;
return (0);
case _PC_PATH_MAX:
*ap->a_retval = PATH_MAX;
return (0);
case _PC_LINK_MAX:
*ap->a_retval = LINK_MAX;
return (0);
case _PC_MAX_CANON:
*ap->a_retval = MAX_CANON;
return (0);
case _PC_MAX_INPUT:
*ap->a_retval = MAX_INPUT;
return (0);
case _PC_PIPE_BUF:
*ap->a_retval = PIPE_BUF;
return (0);
case _PC_CHOWN_RESTRICTED:
*ap->a_retval = 1;
return (0);
case _PC_VDISABLE:
*ap->a_retval = _POSIX_VDISABLE;
return (0);
default:
return (EINVAL);
}
/* NOTREACHED */
}
/*
* Standard lock, unlock and islocked functions.
*/
int
vop_stdlock(ap)
struct vop_lock1_args /* {
struct vnode *a_vp;
int a_flags;
char *file;
int line;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
return (_lockmgr_args(vp->v_vnlock, ap->a_flags, VI_MTX(vp),
LK_WMESG_DEFAULT, LK_PRIO_DEFAULT, LK_TIMO_DEFAULT, ap->a_file,
ap->a_line));
}
/* See above. */
int
vop_stdunlock(ap)
struct vop_unlock_args /* {
struct vnode *a_vp;
int a_flags;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
return (lockmgr(vp->v_vnlock, ap->a_flags | LK_RELEASE, VI_MTX(vp)));
}
/* See above. */
int
vop_stdislocked(ap)
struct vop_islocked_args /* {
struct vnode *a_vp;
} */ *ap;
{
return (lockstatus(ap->a_vp->v_vnlock));
}
/*
* Return true for select/poll.
*/
int
vop_nopoll(ap)
struct vop_poll_args /* {
struct vnode *a_vp;
int a_events;
struct ucred *a_cred;
struct thread *a_td;
} */ *ap;
{
return (poll_no_poll(ap->a_events));
}
/*
* Implement poll for local filesystems that support it.
*/
int
vop_stdpoll(ap)
struct vop_poll_args /* {
struct vnode *a_vp;
int a_events;
struct ucred *a_cred;
struct thread *a_td;
} */ *ap;
{
if (ap->a_events & ~POLLSTANDARD)
return (vn_pollrecord(ap->a_vp, ap->a_td, ap->a_events));
return (ap->a_events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
}
/*
* Return our mount point, as we will take charge of the writes.
*/
int
vop_stdgetwritemount(ap)
struct vop_getwritemount_args /* {
struct vnode *a_vp;
struct mount **a_mpp;
} */ *ap;
{
struct mount *mp;
/*
* XXX Since this is called unlocked we may be recycled while
* attempting to ref the mount. If this is the case or mountpoint
* will be set to NULL. We only have to prevent this call from
* returning with a ref to an incorrect mountpoint. It is not
* harmful to return with a ref to our previous mountpoint.
*/
mp = ap->a_vp->v_mount;
if (mp != NULL) {
vfs_ref(mp);
if (mp != ap->a_vp->v_mount) {
vfs_rel(mp);
mp = NULL;
}
}
*(ap->a_mpp) = mp;
return (0);
}
/* XXX Needs good comment and VOP_BMAP(9) manpage */
int
vop_stdbmap(ap)
struct vop_bmap_args /* {
struct vnode *a_vp;
daddr_t a_bn;
struct bufobj **a_bop;
daddr_t *a_bnp;
int *a_runp;
int *a_runb;
} */ *ap;
{
if (ap->a_bop != NULL)
*ap->a_bop = &ap->a_vp->v_bufobj;
if (ap->a_bnp != NULL)
*ap->a_bnp = ap->a_bn * btodb(ap->a_vp->v_mount->mnt_stat.f_iosize);
if (ap->a_runp != NULL)
*ap->a_runp = 0;
if (ap->a_runb != NULL)
*ap->a_runb = 0;
return (0);
}
int
vop_stdfsync(ap)
struct vop_fsync_args /* {
struct vnode *a_vp;
struct ucred *a_cred;
int a_waitfor;
struct thread *a_td;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
struct buf *bp;
struct bufobj *bo;
struct buf *nbp;
int error = 0;
int maxretry = 1000; /* large, arbitrarily chosen */
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))
continue;
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);
}
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 (ap->a_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)
continue;
if (error == 0 && --maxretry >= 0)
goto loop1;
error = EAGAIN;
}
}
BO_UNLOCK(bo);
if (error == EAGAIN)
vprint("fsync: giving up on dirty", vp);
return (error);
}
/* XXX Needs good comment and more info in the manpage (VOP_GETPAGES(9)). */
int
vop_stdgetpages(ap)
struct vop_getpages_args /* {
struct vnode *a_vp;
vm_page_t *a_m;
int a_count;
int a_reqpage;
vm_ooffset_t a_offset;
} */ *ap;
{
return vnode_pager_generic_getpages(ap->a_vp, ap->a_m,
ap->a_count, ap->a_reqpage);
}
int
vop_stdkqfilter(struct vop_kqfilter_args *ap)
{
return vfs_kqfilter(ap);
}
/* XXX Needs good comment and more info in the manpage (VOP_PUTPAGES(9)). */
int
vop_stdputpages(ap)
struct vop_putpages_args /* {
struct vnode *a_vp;
vm_page_t *a_m;
int a_count;
int a_sync;
int *a_rtvals;
vm_ooffset_t a_offset;
} */ *ap;
{
return vnode_pager_generic_putpages(ap->a_vp, ap->a_m, ap->a_count,
ap->a_sync, ap->a_rtvals);
}
int
vop_stdvptofh(struct vop_vptofh_args *ap)
{
return (EOPNOTSUPP);
}
int
vop_stdvptocnp(struct vop_vptocnp_args *ap)
{
struct vnode *vp = ap->a_vp;
struct vnode **dvp = ap->a_vpp;
struct ucred *cred = ap->a_cred;
char *buf = ap->a_buf;
int *buflen = ap->a_buflen;
char *dirbuf, *cpos;
int i, error, eofflag, dirbuflen, flags, locked, len, covered;
off_t off;
ino_t fileno;
struct vattr va;
struct nameidata nd;
struct thread *td;
struct dirent *dp;
struct vnode *mvp;
i = *buflen;
error = 0;
covered = 0;
td = curthread;
if (vp->v_type != VDIR)
return (ENOENT);
error = VOP_GETATTR(vp, &va, cred);
if (error)
return (error);
VREF(vp);
locked = VOP_ISLOCKED(vp);
VOP_UNLOCK(vp, 0);
NDINIT_ATVP(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE,
"..", vp, td);
flags = FREAD;
error = vn_open_cred(&nd, &flags, 0, VN_OPEN_NOAUDIT, cred, NULL);
if (error) {
vn_lock(vp, locked | LK_RETRY);
return (error);
}
NDFREE(&nd, NDF_ONLY_PNBUF);
mvp = *dvp = nd.ni_vp;
if (vp->v_mount != (*dvp)->v_mount &&
((*dvp)->v_vflag & VV_ROOT) &&
((*dvp)->v_mount->mnt_flag & MNT_UNION)) {
*dvp = (*dvp)->v_mount->mnt_vnodecovered;
VREF(mvp);
VOP_UNLOCK(mvp, 0);
vn_close(mvp, FREAD, cred, td);
VREF(*dvp);
vn_lock(*dvp, LK_EXCLUSIVE | LK_RETRY);
covered = 1;
}
fileno = va.va_fileid;
dirbuflen = DEV_BSIZE;
if (dirbuflen < va.va_blocksize)
dirbuflen = va.va_blocksize;
dirbuf = (char *)malloc(dirbuflen, M_TEMP, M_WAITOK);
if ((*dvp)->v_type != VDIR) {
error = ENOENT;
goto out;
}
off = 0;
len = 0;
do {
/* call VOP_READDIR of parent */
error = get_next_dirent(*dvp, &dp, dirbuf, dirbuflen, &off,
&cpos, &len, &eofflag, td);
if (error)
goto out;
if ((dp->d_type != DT_WHT) &&
(dp->d_fileno == fileno)) {
if (covered) {
VOP_UNLOCK(*dvp, 0);
vn_lock(mvp, LK_EXCLUSIVE | LK_RETRY);
if (dirent_exists(mvp, dp->d_name, td)) {
error = ENOENT;
VOP_UNLOCK(mvp, 0);
vn_lock(*dvp, LK_EXCLUSIVE | LK_RETRY);
goto out;
}
VOP_UNLOCK(mvp, 0);
vn_lock(*dvp, LK_EXCLUSIVE | LK_RETRY);
}
i -= dp->d_namlen;
if (i < 0) {
error = ENOMEM;
goto out;
}
bcopy(dp->d_name, buf + i, dp->d_namlen);
error = 0;
goto out;
}
} while (len > 0 || !eofflag);
error = ENOENT;
out:
free(dirbuf, M_TEMP);
if (!error) {
*buflen = i;
vhold(*dvp);
}
if (covered) {
vput(*dvp);
vrele(mvp);
} else {
VOP_UNLOCK(mvp, 0);
vn_close(mvp, FREAD, cred, td);
}
vn_lock(vp, locked | LK_RETRY);
return (error);
}
int
vop_stdallocate(struct vop_allocate_args *ap)
{
#ifdef __notyet__
struct statfs sfs;
#endif
struct iovec aiov;
struct vattr vattr, *vap;
struct uio auio;
off_t fsize, len, cur, offset;
uint8_t *buf;
struct thread *td;
struct vnode *vp;
size_t iosize;
int error;
buf = NULL;
error = 0;
td = curthread;
vap = &vattr;
vp = ap->a_vp;
len = *ap->a_len;
offset = *ap->a_offset;
error = VOP_GETATTR(vp, vap, td->td_ucred);
if (error != 0)
goto out;
fsize = vap->va_size;
iosize = vap->va_blocksize;
if (iosize == 0)
iosize = BLKDEV_IOSIZE;
if (iosize > MAXPHYS)
iosize = MAXPHYS;
buf = malloc(iosize, M_TEMP, M_WAITOK);
#ifdef __notyet__
/*
* Check if the filesystem sets f_maxfilesize; if not use
* VOP_SETATTR to perform the check.
*/
error = VFS_STATFS(vp->v_mount, &sfs, td);
if (error != 0)
goto out;
if (sfs.f_maxfilesize) {
if (offset > sfs.f_maxfilesize || len > sfs.f_maxfilesize ||
offset + len > sfs.f_maxfilesize) {
error = EFBIG;
goto out;
}
} else
#endif
if (offset + len > vap->va_size) {
/*
* Test offset + len against the filesystem's maxfilesize.
*/
VATTR_NULL(vap);
vap->va_size = offset + len;
error = VOP_SETATTR(vp, vap, td->td_ucred);
if (error != 0)
goto out;
VATTR_NULL(vap);
vap->va_size = fsize;
error = VOP_SETATTR(vp, vap, td->td_ucred);
if (error != 0)
goto out;
}
for (;;) {
/*
* Read and write back anything below the nominal file
* size. There's currently no way outside the filesystem
* to know whether this area is sparse or not.
*/
cur = iosize;
if ((offset % iosize) != 0)
cur -= (offset % iosize);
if (cur > len)
cur = len;
if (offset < fsize) {
aiov.iov_base = buf;
aiov.iov_len = cur;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_offset = offset;
auio.uio_resid = cur;
auio.uio_segflg = UIO_SYSSPACE;
auio.uio_rw = UIO_READ;
auio.uio_td = td;
error = VOP_READ(vp, &auio, 0, td->td_ucred);
if (error != 0)
break;
if (auio.uio_resid > 0) {
bzero(buf + cur - auio.uio_resid,
auio.uio_resid);
}
} else {
bzero(buf, cur);
}
aiov.iov_base = buf;
aiov.iov_len = cur;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_offset = offset;
auio.uio_resid = cur;
auio.uio_segflg = UIO_SYSSPACE;
auio.uio_rw = UIO_WRITE;
auio.uio_td = td;
error = VOP_WRITE(vp, &auio, 0, td->td_ucred);
if (error != 0)
break;
len -= cur;
offset += cur;
if (len == 0)
break;
if (should_yield())
break;
}
out:
*ap->a_len = len;
*ap->a_offset = offset;
free(buf, M_TEMP);
return (error);
}
/*
* vfs default ops
* used to fill the vfs function table to get reasonable default return values.
*/
int
vfs_stdroot (mp, flags, vpp)
struct mount *mp;
int flags;
struct vnode **vpp;
{
return (EOPNOTSUPP);
}
int
vfs_stdstatfs (mp, sbp)
struct mount *mp;
struct statfs *sbp;
{
return (EOPNOTSUPP);
}
int
vfs_stdquotactl (mp, cmds, uid, arg)
struct mount *mp;
int cmds;
uid_t uid;
void *arg;
{
return (EOPNOTSUPP);
}
int
vfs_stdsync(mp, waitfor)
struct mount *mp;
int waitfor;
{
struct vnode *vp, *mvp;
struct thread *td;
int error, lockreq, allerror = 0;
td = curthread;
lockreq = LK_EXCLUSIVE | LK_INTERLOCK;
if (waitfor != MNT_WAIT)
lockreq |= LK_NOWAIT;
/*
* Force stale buffer cache information to be flushed.
*/
MNT_ILOCK(mp);
loop:
MNT_VNODE_FOREACH(vp, mp, mvp) {
/* bv_cnt is an acceptable race here. */
if (vp->v_bufobj.bo_dirty.bv_cnt == 0)
continue;
VI_LOCK(vp);
MNT_IUNLOCK(mp);
if ((error = vget(vp, lockreq, td)) != 0) {
MNT_ILOCK(mp);
if (error == ENOENT) {
MNT_VNODE_FOREACH_ABORT_ILOCKED(mp, mvp);
goto loop;
}
continue;
}
error = VOP_FSYNC(vp, waitfor, td);
if (error)
allerror = error;
vput(vp);
MNT_ILOCK(mp);
}
MNT_IUNLOCK(mp);
return (allerror);
}
int
vfs_stdnosync (mp, waitfor)
struct mount *mp;
int waitfor;
{
return (0);
}
int
vfs_stdvget (mp, ino, flags, vpp)
struct mount *mp;
ino_t ino;
int flags;
struct vnode **vpp;
{
return (EOPNOTSUPP);
}
int
vfs_stdfhtovp (mp, fhp, vpp)
struct mount *mp;
struct fid *fhp;
struct vnode **vpp;
{
return (EOPNOTSUPP);
}
int
vfs_stdinit (vfsp)
struct vfsconf *vfsp;
{
return (0);
}
int
vfs_stduninit (vfsp)
struct vfsconf *vfsp;
{
return(0);
}
int
vfs_stdextattrctl(mp, cmd, filename_vp, attrnamespace, attrname)
struct mount *mp;
int cmd;
struct vnode *filename_vp;
int attrnamespace;
const char *attrname;
{
if (filename_vp != NULL)
VOP_UNLOCK(filename_vp, 0);
return (EOPNOTSUPP);
}
int
vfs_stdsysctl(mp, op, req)
struct mount *mp;
fsctlop_t op;
struct sysctl_req *req;
{
return (EOPNOTSUPP);
}
/* end of vfs default ops */