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Add line info and SET_ERROR() to ZFS debug log 

Redefine the SET_ERROR macro in terms of __dprintf() so the error
return codes get logged as both tracepoint events (if tracepoints are
enabled) and as ZFS debug log entries.  This also allows us to use
the same definition of SET_ERROR() in kernel and user space.

Define a new debug flag ZFS_DEBUG_SET_ERROR=512 that may be bitwise
or'd into zfs_flags. Setting this flag enables both dprintf() and
SET_ERROR() messages in the debug log. That is, setting
ZFS_DEBUG_SET_ERROR and ZFS_DEBUG_DPRINTF|ZFS_DEBUG_SET_ERROR are
equivalent (this was done for sake of simplicity). Leaving
ZFS_DEBUG_SET_ERROR unset suppresses the SET_ERROR() messages which
helps avoid cluttering up the logs.

To enable SET_ERROR() logging, run:

  echo 1 >   /sys/module/zfs/parameters/zfs_dbgmsg_enable
  echo 512 > /sys/module/zfs/parameters/zfs_flags

Remove the zfs_set_error_class tracepoints event class since
SET_ERROR() now uses __dprintf(). This sacrifices a bit of
granularity when selecting individual tracepoint events to enable but
it makes the code simpler.

Include file, function, and line number information in debug log
entries.  The information is now added to the message buffer in
__dprintf() and as a result the zfs_dprintf_class tracepoints event
class was changed from a 4 parameter interface to a single parameter.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Closes #6400
This commit is contained in:
Ned Bass 2017-07-25 23:09:48 -07:00 committed by Brian Behlendorf
parent 9ff13dbe92
commit 8740cf4a2f
6 changed files with 37 additions and 102 deletions
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20
include/sys/sdt.h
View File

@ -34,13 +34,8 @@
#define ZFS_PROBE2(a, c, e) ((void) 0)
#define ZFS_PROBE3(a, c, e, g) ((void) 0)
#define ZFS_PROBE4(a, c, e, g, i) ((void) 0)
#define ZFS_SET_ERROR(err) ((void) 0)
#else
#if defined(HAVE_DECLARE_EVENT_CLASS)
#include <sys/trace.h>
#endif /* _KERNEL */
/*
* The set-error SDT probe is extra static, in that we declare its fake
@ -55,16 +50,9 @@
* twice, so it should not have side effects (e.g. something like:
* "return (SET_ERROR(log_error(EINVAL, info)));" would log the error twice).
*/
#define SET_ERROR(err) \
(trace_zfs_set__error(__FILE__, __func__, __LINE__, err), err)
#else
extern void __set_error(const char *file, const char *func, int line, int err);
#undef SET_ERROR
#define SET_ERROR(err) (err)
#endif /* HAVE_DECLARE_EVENT_CLASS */
#endif /* _KERNEL */
#define SET_ERROR(err) \
(__set_error(__FILE__, __func__, __LINE__, err), err)
#endif /* _SYS_SDT_H */

77
include/sys/trace_dbgmsg.h
View File

@ -37,92 +37,29 @@
*/
/*
* Generic support for four argument tracepoints of the form:
* Generic support for one argument tracepoints of the form:
*
* DTRACE_PROBE4(...,
* const char *, ...,
* const char *, ...,
* int, ...,
* DTRACE_PROBE1(...,
* const char *, ...);
*/
/* BEGIN CSTYLED */
DECLARE_EVENT_CLASS(zfs_dprintf_class,
TP_PROTO(const char *file, const char *function, int line,
const char *msg),
TP_ARGS(file, function, line, msg),
TP_PROTO(const char *msg),
TP_ARGS(msg),
TP_STRUCT__entry(
__string(file, file)
__string(function, function)
__field(int, line)
__string(msg, msg)
),
TP_fast_assign(
__assign_str(file, strchr(file, '/') ?
strrchr(file, '/') + 1 : file)
__assign_str(function, function);
__entry->line = line;
__assign_str(msg, msg);
),
TP_printk("%s:%d:%s(): %s", __get_str(file), __entry->line,
__get_str(function), __get_str(msg))
TP_printk("%s", __get_str(msg))
);
/* END CSTYLED */
/* BEGIN CSTYLED */
#define DEFINE_DPRINTF_EVENT(name) \
DEFINE_EVENT(zfs_dprintf_class, name, \
TP_PROTO(const char *file, const char *function, int line, \
const char *msg), \
TP_ARGS(file, function, line, msg))
TP_PROTO(const char *msg), \
TP_ARGS(msg))
/* END CSTYLED */
DEFINE_DPRINTF_EVENT(zfs_zfs__dprintf);
/*
* Generic support for four argument tracepoints of the form:
*
* DTRACE_PROBE4(...,
* const char *, ...,
* const char *, ...,
* int, ...,
* uintptr_t, ...);
*/
/* BEGIN CSTYLED */
DECLARE_EVENT_CLASS(zfs_set_error_class,
TP_PROTO(const char *file, const char *function, int line,
uintptr_t error),
TP_ARGS(file, function, line, error),
TP_STRUCT__entry(
__string(file, file)
__string(function, function)
__field(int, line)
__field(uintptr_t, error)
),
TP_fast_assign(
__assign_str(file, strchr(file, '/') ?
strrchr(file, '/') + 1 : file)
__assign_str(function, function);
__entry->line = line;
__entry->error = error;
),
TP_printk("%s:%d:%s(): error 0x%lx", __get_str(file), __entry->line,
__get_str(function), __entry->error)
);
/* END CSTYLED */
/* BEGIN CSTYLED */
#ifdef TP_CONDITION
#define DEFINE_SET_ERROR_EVENT(name) \
DEFINE_EVENT_CONDITION(zfs_set_error_class, name, \
TP_PROTO(const char *file, const char *function, int line, \
uintptr_t error), \
TP_ARGS(file, function, line, error), \
TP_CONDITION(error))
#else
#define DEFINE_SET_ERROR_EVENT(name) \
DEFINE_EVENT(zfs_set_error_class, name, \
TP_PROTO(const char *file, const char *function, int line, \
uintptr_t error), \
TP_ARGS(file, function, line, error))
#endif
/* END CSTYLED */
DEFINE_SET_ERROR_EVENT(zfs_set__error);

9
include/sys/zfs_context.h
View File

@ -206,15 +206,6 @@ extern int aok;
ZFS_PROBE4(#a, (unsigned long)c, (unsigned long)e, (unsigned long)g, \
(unsigned long)i)
/*
* We use the comma operator so that this macro can be used without much
* additional code. For example, "return (EINVAL);" becomes
* "return (SET_ERROR(EINVAL));". Note that the argument will be evaluated
* twice, so it should not have side effects (e.g. something like:
* "return (SET_ERROR(log_error(EINVAL, info)));" would log the error twice).
*/
#define SET_ERROR(err) (ZFS_SET_ERROR(err), err)
/*
* Threads. TS_STACK_MIN is dictated by the minimum allowed pthread stack
* size. While TS_STACK_MAX is somewhat arbitrary, it was selected to be

1
include/sys/zfs_debug.h
View File

@ -51,6 +51,7 @@ extern int zfs_free_leak_on_eio;
#define ZFS_DEBUG_ZIO_FREE (1 << 6)
#define ZFS_DEBUG_HISTOGRAM_VERIFY (1 << 7)
#define ZFS_DEBUG_METASLAB_VERIFY (1 << 8)
#define ZFS_DEBUG_SET_ERROR (1 << 9)
extern void __dprintf(const char *file, const char *func,
int line, const char *fmt, ...);

6
man/man5/zfs-module-parameters.5
View File

@ -1258,6 +1258,12 @@ _
_
128 ZFS_DEBUG_HISTOGRAM_VERIFY
Enable extra spacemap histogram verifications.
_
256 ZFS_DEBUG_METASLAB_VERIFY
Verify space accounting on disk matches in-core range_trees.
_
512 ZFS_DEBUG_SET_ERROR
Enable SET_ERROR and dprintf entries in the debug log.
.TE
.sp
* Requires debug build.

26
module/zfs/zfs_debug.c
View File

@ -161,6 +161,13 @@ __zfs_dbgmsg(char *buf)
mutex_exit(&zfs_dbgmsgs_lock);
}
void
__set_error(const char *file, const char *func, int line, int err)
{
if (zfs_flags & ZFS_DEBUG_SET_ERROR)
__dprintf(file, func, line, "error %lu", err);
}
#ifdef _KERNEL
void
__dprintf(const char *file, const char *func, int line, const char *fmt, ...)
@ -170,8 +177,10 @@ __dprintf(const char *file, const char *func, int line, const char *fmt, ...)
size_t size;
char *buf;
char *nl;
int i;
if (!zfs_dbgmsg_enable && !(zfs_flags & ZFS_DEBUG_DPRINTF))
if (!zfs_dbgmsg_enable &&
!(zfs_flags & (ZFS_DEBUG_DPRINTF | ZFS_DEBUG_SET_ERROR)))
return;
size = 1024;
@ -187,9 +196,13 @@ __dprintf(const char *file, const char *func, int line, const char *fmt, ...)
newfile = file;
}
va_start(adx, fmt);
(void) vsnprintf(buf, size, fmt, adx);
va_end(adx);
i = snprintf(buf, size, "%s:%d:%s(): ", 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.
@ -209,9 +222,8 @@ __dprintf(const char *file, const char *func, int line, const char *fmt, ...)
* # Dump the ring buffer.
* $ cat /sys/kernel/debug/tracing/trace
*/
if (zfs_flags & ZFS_DEBUG_DPRINTF)
DTRACE_PROBE4(zfs__dprintf,
char *, newfile, char *, func, int, line, char *, buf);
if (zfs_flags & (ZFS_DEBUG_DPRINTF | ZFS_DEBUG_SET_ERROR))
DTRACE_PROBE1(zfs__dprintf, char *, buf);
/*
* To get this data enable the zfs debug log as shown: