mirror_zfs/module/os/freebsd/zfs/zfs_file_os.c
George Wilson 958826be7a
file reference counts can get corrupted
Callers of zfs_file_get and zfs_file_put can corrupt the reference
counts for the file structure resulting in a panic or a soft lockup.
When zfs send/recv runs, it will add a reference count to the
open file, and begin to send or recv the stream. If the file descriptor
is closed, then when dmu_recv_stream() or dmu_send() return we will
call zfs_file_put to remove the reference we placed on the file
structure. Unfortunately, because zfs_file_put() uses the file
descriptor to lookup the file structure, it may end up finding that
the file descriptor table no longer contains the file struct, thus
leaking the file structure. Or it might end up finding a file
descriptor for a different file and blindly updating its reference
counts. Other failure modes probably exists.

This change reworks the zfs_file_[get|put] interface to not rely
on the file descriptor but instead pass the zfs_file_t pointer around.

Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Mark Maybee <mark.maybee@delphix.com>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Co-authored-by: Allan Jude <allan@klarasystems.com>
Signed-off-by: George Wilson <gwilson@delphix.com>
External-issue: DLPX-76119
Closes #12299
2021-07-10 19:00:37 -06:00

300 lines
6.6 KiB
C

/*
* Copyright (c) 2020 iXsystems, Inc.
* All rights reserved.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS 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 AUTHORS 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/dmu.h>
#include <sys/dmu_impl.h>
#include <sys/dmu_recv.h>
#include <sys/dmu_tx.h>
#include <sys/dbuf.h>
#include <sys/dnode.h>
#include <sys/zfs_context.h>
#include <sys/dmu_objset.h>
#include <sys/dmu_traverse.h>
#include <sys/dsl_dataset.h>
#include <sys/dsl_dir.h>
#include <sys/dsl_pool.h>
#include <sys/dsl_synctask.h>
#include <sys/zfs_ioctl.h>
#include <sys/zap.h>
#include <sys/zio_checksum.h>
#include <sys/zfs_znode.h>
#include <sys/zfs_file.h>
#include <sys/buf.h>
#include <sys/stat.h>
int
zfs_file_open(const char *path, int flags, int mode, zfs_file_t **fpp)
{
struct thread *td;
int rc, fd;
td = curthread;
pwd_ensure_dirs();
/* 12.x doesn't take a const char * */
rc = kern_openat(td, AT_FDCWD, __DECONST(char *, path),
UIO_SYSSPACE, flags, mode);
if (rc)
return (SET_ERROR(rc));
fd = td->td_retval[0];
td->td_retval[0] = 0;
if (fget(curthread, fd, &cap_no_rights, fpp))
kern_close(td, fd);
return (0);
}
void
zfs_file_close(zfs_file_t *fp)
{
fo_close(fp, curthread);
}
static int
zfs_file_write_impl(zfs_file_t *fp, const void *buf, size_t count, loff_t *offp,
ssize_t *resid)
{
ssize_t rc;
struct uio auio;
struct thread *td;
struct iovec aiov;
td = curthread;
aiov.iov_base = (void *)(uintptr_t)buf;
aiov.iov_len = count;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_segflg = UIO_SYSSPACE;
auio.uio_resid = count;
auio.uio_rw = UIO_WRITE;
auio.uio_td = td;
auio.uio_offset = *offp;
if ((fp->f_flag & FWRITE) == 0)
return (SET_ERROR(EBADF));
if (fp->f_type == DTYPE_VNODE)
bwillwrite();
rc = fo_write(fp, &auio, td->td_ucred, FOF_OFFSET, td);
if (rc)
return (SET_ERROR(rc));
if (resid)
*resid = auio.uio_resid;
else if (auio.uio_resid)
return (SET_ERROR(EIO));
*offp += count - auio.uio_resid;
return (rc);
}
int
zfs_file_write(zfs_file_t *fp, const void *buf, size_t count, ssize_t *resid)
{
loff_t off = fp->f_offset;
ssize_t rc;
rc = zfs_file_write_impl(fp, buf, count, &off, resid);
if (rc == 0)
fp->f_offset = off;
return (SET_ERROR(rc));
}
int
zfs_file_pwrite(zfs_file_t *fp, const void *buf, size_t count, loff_t off,
ssize_t *resid)
{
return (zfs_file_write_impl(fp, buf, count, &off, resid));
}
static int
zfs_file_read_impl(zfs_file_t *fp, void *buf, size_t count, loff_t *offp,
ssize_t *resid)
{
ssize_t rc;
struct uio auio;
struct thread *td;
struct iovec aiov;
td = curthread;
aiov.iov_base = (void *)(uintptr_t)buf;
aiov.iov_len = count;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_segflg = UIO_SYSSPACE;
auio.uio_resid = count;
auio.uio_rw = UIO_READ;
auio.uio_td = td;
auio.uio_offset = *offp;
if ((fp->f_flag & FREAD) == 0)
return (SET_ERROR(EBADF));
rc = fo_read(fp, &auio, td->td_ucred, FOF_OFFSET, td);
if (rc)
return (SET_ERROR(rc));
if (resid)
*resid = auio.uio_resid;
*offp += count - auio.uio_resid;
return (SET_ERROR(0));
}
int
zfs_file_read(zfs_file_t *fp, void *buf, size_t count, ssize_t *resid)
{
loff_t off = fp->f_offset;
ssize_t rc;
rc = zfs_file_read_impl(fp, buf, count, &off, resid);
if (rc == 0)
fp->f_offset = off;
return (rc);
}
int
zfs_file_pread(zfs_file_t *fp, void *buf, size_t count, loff_t off,
ssize_t *resid)
{
return (zfs_file_read_impl(fp, buf, count, &off, resid));
}
int
zfs_file_seek(zfs_file_t *fp, loff_t *offp, int whence)
{
int rc;
struct thread *td;
td = curthread;
if ((fp->f_ops->fo_flags & DFLAG_SEEKABLE) == 0)
return (SET_ERROR(ESPIPE));
rc = fo_seek(fp, *offp, whence, td);
if (rc == 0)
*offp = td->td_uretoff.tdu_off;
return (SET_ERROR(rc));
}
int
zfs_file_getattr(zfs_file_t *fp, zfs_file_attr_t *zfattr)
{
struct thread *td;
struct stat sb;
int rc;
td = curthread;
rc = fo_stat(fp, &sb, td->td_ucred, td);
if (rc)
return (SET_ERROR(rc));
zfattr->zfa_size = sb.st_size;
zfattr->zfa_mode = sb.st_mode;
return (0);
}
static __inline int
zfs_vop_fsync(vnode_t *vp)
{
struct mount *mp;
int error;
if ((error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) != 0)
goto drop;
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
error = VOP_FSYNC(vp, MNT_WAIT, curthread);
VOP_UNLOCK1(vp);
vn_finished_write(mp);
drop:
return (SET_ERROR(error));
}
int
zfs_file_fsync(zfs_file_t *fp, int flags)
{
if (fp->f_type != DTYPE_VNODE)
return (EINVAL);
return (zfs_vop_fsync(fp->f_vnode));
}
zfs_file_t *
zfs_file_get(int fd)
{
struct file *fp;
if (fget(curthread, fd, &cap_no_rights, &fp))
return (NULL);
return (fp);
}
void
zfs_file_put(zfs_file_t *fp)
{
fdrop(fp, curthread);
}
loff_t
zfs_file_off(zfs_file_t *fp)
{
return (fp->f_offset);
}
void *
zfs_file_private(zfs_file_t *fp)
{
file_t *tmpfp;
void *data;
int error;
tmpfp = curthread->td_fpop;
curthread->td_fpop = fp;
error = devfs_get_cdevpriv(&data);
curthread->td_fpop = tmpfp;
if (error != 0)
return (NULL);
return (data);
}
int
zfs_file_unlink(const char *fnamep)
{
zfs_uio_seg_t seg = UIO_SYSSPACE;
int rc;
#if __FreeBSD_version >= 1300018
rc = kern_funlinkat(curthread, AT_FDCWD, fnamep, FD_NONE, seg, 0, 0);
#elif __FreeBSD_version >= 1202504 || defined(AT_BENEATH)
rc = kern_unlinkat(curthread, AT_FDCWD, __DECONST(char *, fnamep),
seg, 0, 0);
#else
rc = kern_unlinkat(curthread, AT_FDCWD, __DECONST(char *, fnamep),
seg, 0);
#endif
return (SET_ERROR(rc));
}