mirror_zfs/include/sys/fm/util.h
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

122 lines
3.7 KiB
C

/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
*/
#ifndef _SYS_FM_UTIL_H
#define _SYS_FM_UTIL_H
#ifdef __cplusplus
extern "C" {
#endif
#include <sys/nvpair.h>
#include <sys/zfs_file.h>
/*
* Shared user/kernel definitions for class length, error channel name,
* and kernel event publisher string.
*/
#define FM_MAX_CLASS 100
#define FM_ERROR_CHAN "com.sun:fm:error"
#define FM_PUB "fm"
/*
* ereport dump device transport support
*
* Ereports are written out to the dump device at a proscribed offset from the
* end, similar to in-transit log messages. The ereports are represented as a
* erpt_dump_t header followed by ed_size bytes of packed native nvlist data.
*
* NOTE: All of these constants and the header must be defined so they have the
* same representation for *both* 32-bit and 64-bit producers and consumers.
*/
#define ERPT_MAGIC 0xf00d4eddU
#define ERPT_MAX_ERRS 16
#define ERPT_DATA_SZ (6 * 1024)
#define ERPT_EVCH_MAX 256
#define ERPT_HIWAT 64
typedef struct erpt_dump {
uint32_t ed_magic; /* ERPT_MAGIC or zero to indicate end */
uint32_t ed_chksum; /* checksum32() of packed nvlist data */
uint32_t ed_size; /* ereport (nvl) fixed buf size */
uint32_t ed_pad; /* reserved for future use */
hrtime_t ed_hrt_nsec; /* hrtime of this ereport */
hrtime_t ed_hrt_base; /* hrtime sample corresponding to ed_tod_base */
struct {
uint64_t sec; /* seconds since gettimeofday() Epoch */
uint64_t nsec; /* nanoseconds past ed_tod_base.sec */
} ed_tod_base;
} erpt_dump_t;
#ifdef _KERNEL
#define ZEVENT_SHUTDOWN 0x1
typedef void zevent_cb_t(nvlist_t *, nvlist_t *);
typedef struct zevent_s {
nvlist_t *ev_nvl; /* protected by the zevent_lock */
nvlist_t *ev_detector; /* " */
list_t ev_ze_list; /* " */
list_node_t ev_node; /* " */
zevent_cb_t *ev_cb; /* " */
uint64_t ev_eid;
} zevent_t;
typedef struct zfs_zevent {
zevent_t *ze_zevent; /* protected by the zevent_lock */
list_node_t ze_node; /* " */
uint64_t ze_dropped; /* " */
} zfs_zevent_t;
extern void fm_init(void);
extern void fm_fini(void);
extern void zfs_zevent_post_cb(nvlist_t *nvl, nvlist_t *detector);
extern int zfs_zevent_post(nvlist_t *, nvlist_t *, zevent_cb_t *);
extern void zfs_zevent_drain_all(int *);
extern zfs_file_t *zfs_zevent_fd_hold(int, minor_t *, zfs_zevent_t **);
extern void zfs_zevent_fd_rele(zfs_file_t *);
extern int zfs_zevent_next(zfs_zevent_t *, nvlist_t **, uint64_t *, uint64_t *);
extern int zfs_zevent_wait(zfs_zevent_t *);
extern int zfs_zevent_seek(zfs_zevent_t *, uint64_t);
extern void zfs_zevent_init(zfs_zevent_t **);
extern void zfs_zevent_destroy(zfs_zevent_t *);
extern void zfs_zevent_track_duplicate(void);
extern void zfs_ereport_init(void);
extern void zfs_ereport_fini(void);
#else
static inline void fm_init(void) { }
static inline void fm_fini(void) { }
#endif /* _KERNEL */
#ifdef __cplusplus
}
#endif
#endif /* _SYS_FM_UTIL_H */