zfs-builds-mm/zfs-0.8.2/module/zfs/zfs_debug.c

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2019-10-24 23:13:56 +02:00
/*
* 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) 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2012, 2014 by Delphix. All rights reserved.
*/
#include <sys/zfs_context.h>
typedef struct zfs_dbgmsg {
procfs_list_node_t zdm_node;
time_t zdm_timestamp;
int zdm_size;
char zdm_msg[1]; /* variable length allocation */
} zfs_dbgmsg_t;
procfs_list_t zfs_dbgmsgs;
int zfs_dbgmsg_size = 0;
int zfs_dbgmsg_maxsize = 4<<20; /* 4MB */
/*
* Internal ZFS debug messages are enabled by default.
*
* # Print debug messages
* cat /proc/spl/kstat/zfs/dbgmsg
*
* # Disable the kernel debug message log.
* echo 0 > /sys/module/zfs/parameters/zfs_dbgmsg_enable
*
* # Clear the kernel debug message log.
* echo 0 >/proc/spl/kstat/zfs/dbgmsg
*/
int zfs_dbgmsg_enable = 1;
static int
zfs_dbgmsg_show_header(struct seq_file *f)
{
seq_printf(f, "%-12s %-8s\n", "timestamp", "message");
return (0);
}
static int
zfs_dbgmsg_show(struct seq_file *f, void *p)
{
zfs_dbgmsg_t *zdm = (zfs_dbgmsg_t *)p;
seq_printf(f, "%-12llu %-s\n",
(u_longlong_t)zdm->zdm_timestamp, zdm->zdm_msg);
return (0);
}
static void
zfs_dbgmsg_purge(int max_size)
{
while (zfs_dbgmsg_size > max_size) {
zfs_dbgmsg_t *zdm = list_remove_head(&zfs_dbgmsgs.pl_list);
if (zdm == NULL)
return;
int size = zdm->zdm_size;
kmem_free(zdm, size);
zfs_dbgmsg_size -= size;
}
}
static int
zfs_dbgmsg_clear(procfs_list_t *procfs_list)
{
mutex_enter(&zfs_dbgmsgs.pl_lock);
zfs_dbgmsg_purge(0);
mutex_exit(&zfs_dbgmsgs.pl_lock);
return (0);
}
void
zfs_dbgmsg_init(void)
{
procfs_list_install("zfs",
"dbgmsg",
0600,
&zfs_dbgmsgs,
zfs_dbgmsg_show,
zfs_dbgmsg_show_header,
zfs_dbgmsg_clear,
offsetof(zfs_dbgmsg_t, zdm_node));
}
void
zfs_dbgmsg_fini(void)
{
procfs_list_uninstall(&zfs_dbgmsgs);
zfs_dbgmsg_purge(0);
/*
* TODO - decide how to make this permanent
*/
#ifdef _KERNEL
procfs_list_destroy(&zfs_dbgmsgs);
#endif
}
void
__set_error(const char *file, const char *func, int line, int err)
{
/*
* To enable this:
*
* $ echo 512 >/sys/module/zfs/parameters/zfs_flags
*/
if (zfs_flags & ZFS_DEBUG_SET_ERROR)
__dprintf(B_FALSE, file, func, line, "error %lu", err);
}
void
__zfs_dbgmsg(char *buf)
{
int size = sizeof (zfs_dbgmsg_t) + strlen(buf);
zfs_dbgmsg_t *zdm = kmem_zalloc(size, KM_SLEEP);
zdm->zdm_size = size;
zdm->zdm_timestamp = gethrestime_sec();
strcpy(zdm->zdm_msg, buf);
mutex_enter(&zfs_dbgmsgs.pl_lock);
procfs_list_add(&zfs_dbgmsgs, zdm);
zfs_dbgmsg_size += size;
zfs_dbgmsg_purge(MAX(zfs_dbgmsg_maxsize, 0));
mutex_exit(&zfs_dbgmsgs.pl_lock);
}
#ifdef _KERNEL
void
__dprintf(boolean_t dprint, const char *file, const char *func,
int line, const char *fmt, ...)
{
const char *newfile;
va_list adx;
size_t size;
char *buf;
char *nl;
int i;
char *prefix = (dprint) ? "dprintf: " : "";
size = 1024;
buf = kmem_alloc(size, KM_SLEEP);
/*
* Get rid of annoying prefix to filename.
*/
newfile = strrchr(file, '/');
if (newfile != NULL) {
newfile = newfile + 1; /* Get rid of leading / */
} else {
newfile = file;
}
i = snprintf(buf, size, "%s%s:%d:%s(): ", prefix, newfile, line, func);
if (i < size) {
va_start(adx, fmt);
(void) vsnprintf(buf + i, size - i, fmt, adx);
va_end(adx);
}
/*
* Get rid of trailing newline for dprintf logs.
*/
if (dprint && buf[0] != '\0') {
nl = &buf[strlen(buf) - 1];
if (*nl == '\n')
*nl = '\0';
}
/*
* To get this data enable the zfs__dprintf trace point as shown:
*
* # Enable zfs__dprintf tracepoint, clear the tracepoint ring buffer
* $ echo 1 > /sys/kernel/debug/tracing/events/zfs/enable
* $ echo 0 > /sys/kernel/debug/tracing/trace
*
* # Dump the ring buffer.
* $ cat /sys/kernel/debug/tracing/trace
*/
DTRACE_PROBE1(zfs__dprintf, char *, buf);
/*
* To get this data:
*
* $ cat /proc/spl/kstat/zfs/dbgmsg
*
* To clear the buffer:
* $ echo 0 > /proc/spl/kstat/zfs/dbgmsg
*/
__zfs_dbgmsg(buf);
kmem_free(buf, size);
}
#else
void
zfs_dbgmsg_print(const char *tag)
{
ssize_t ret __attribute__((unused));
/*
* We use write() in this function instead of printf()
* so it is safe to call from a signal handler.
*/
ret = write(STDOUT_FILENO, "ZFS_DBGMSG(", 11);
ret = write(STDOUT_FILENO, tag, strlen(tag));
ret = write(STDOUT_FILENO, ") START:\n", 9);
mutex_enter(&zfs_dbgmsgs.pl_lock);
for (zfs_dbgmsg_t *zdm = list_head(&zfs_dbgmsgs.pl_list); zdm != NULL;
zdm = list_next(&zfs_dbgmsgs.pl_list, zdm)) {
ret = write(STDOUT_FILENO, zdm->zdm_msg,
strlen(zdm->zdm_msg));
ret = write(STDOUT_FILENO, "\n", 1);
}
ret = write(STDOUT_FILENO, "ZFS_DBGMSG(", 11);
ret = write(STDOUT_FILENO, tag, strlen(tag));
ret = write(STDOUT_FILENO, ") END\n", 6);
mutex_exit(&zfs_dbgmsgs.pl_lock);
}
#endif /* _KERNEL */
#ifdef _KERNEL
module_param(zfs_dbgmsg_enable, int, 0644);
MODULE_PARM_DESC(zfs_dbgmsg_enable, "Enable ZFS debug message log");
module_param(zfs_dbgmsg_maxsize, int, 0644);
MODULE_PARM_DESC(zfs_dbgmsg_maxsize, "Maximum ZFS debug log size");
#endif