[PATCH] OCFS2: The Second Oracle Cluster Filesystem

Very simple printk wrapper which adds the ability to enable various
sets of debug messages at run-time.
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Signed-off-by: Kurt Hackel <kurt.hackel@oracle.com>

fs/ocfs2/cluster/masklog.c

+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * Copyright (C) 2004, 2005 Oracle.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/string.h>
+#include <asm/uaccess.h>
+
+#include "masklog.h"
+
+struct mlog_bits mlog_and_bits = MLOG_BITS_RHS(MLOG_INITIAL_AND_MASK);
+EXPORT_SYMBOL_GPL(mlog_and_bits);
+struct mlog_bits mlog_not_bits = MLOG_BITS_RHS(MLOG_INITIAL_NOT_MASK);
+EXPORT_SYMBOL_GPL(mlog_not_bits);
+
+static ssize_t mlog_mask_show(u64 mask, char *buf)
+{
+	char *state;
+
+	if (__mlog_test_u64(mask, mlog_and_bits))
+		state = "allow";
+	else if (__mlog_test_u64(mask, mlog_not_bits))
+		state = "deny";
+	else
+		state = "off";
+
+	return snprintf(buf, PAGE_SIZE, "%s\n", state);
+}
+
+static ssize_t mlog_mask_store(u64 mask, const char *buf, size_t count)
+{
+	if (!strnicmp(buf, "allow", 5)) {
+		__mlog_set_u64(mask, mlog_and_bits);
+		__mlog_clear_u64(mask, mlog_not_bits);
+	} else if (!strnicmp(buf, "deny", 4)) {
+		__mlog_set_u64(mask, mlog_not_bits);
+		__mlog_clear_u64(mask, mlog_and_bits);
+	} else if (!strnicmp(buf, "off", 3)) {
+		__mlog_clear_u64(mask, mlog_not_bits);
+		__mlog_clear_u64(mask, mlog_and_bits);
+	} else
+		return -EINVAL;
+
+	return count;
+}
+
+struct mlog_attribute {
+	struct attribute attr;
+	u64 mask;
+};
+
+#define to_mlog_attr(_attr) container_of(_attr, struct mlog_attribute, attr)
+
+#define define_mask(_name) {			\
+	.attr = {				\
+		.name = #_name,			\
+		.mode = S_IRUGO | S_IWUSR,	\
+	},					\
+	.mask = ML_##_name,			\
+}
+
+static struct mlog_attribute mlog_attrs[MLOG_MAX_BITS] = {
+	define_mask(ENTRY),
+	define_mask(EXIT),
+	define_mask(TCP),
+	define_mask(MSG),
+	define_mask(SOCKET),
+	define_mask(HEARTBEAT),
+	define_mask(HB_BIO),
+	define_mask(DLMFS),
+	define_mask(DLM),
+	define_mask(DLM_DOMAIN),
+	define_mask(DLM_THREAD),
+	define_mask(DLM_MASTER),
+	define_mask(DLM_RECOVERY),
+	define_mask(AIO),
+	define_mask(JOURNAL),
+	define_mask(DISK_ALLOC),
+	define_mask(SUPER),
+	define_mask(FILE_IO),
+	define_mask(EXTENT_MAP),
+	define_mask(DLM_GLUE),
+	define_mask(BH_IO),
+	define_mask(UPTODATE),
+	define_mask(NAMEI),
+	define_mask(INODE),
+	define_mask(VOTE),
+	define_mask(DCACHE),
+	define_mask(CONN),
+	define_mask(QUORUM),
+	define_mask(EXPORT),
+	define_mask(ERROR),
+	define_mask(NOTICE),
+	define_mask(KTHREAD),
+};
+
+static struct attribute *mlog_attr_ptrs[MLOG_MAX_BITS] = {NULL, };
+
+static ssize_t mlog_show(struct kobject *obj, struct attribute *attr,
+			 char *buf)
+{
+	struct mlog_attribute *mlog_attr = to_mlog_attr(attr);
+
+	return mlog_mask_show(mlog_attr->mask, buf);
+}
+
+static ssize_t mlog_store(struct kobject *obj, struct attribute *attr,
+			  const char *buf, size_t count)
+{
+	struct mlog_attribute *mlog_attr = to_mlog_attr(attr);
+
+	return mlog_mask_store(mlog_attr->mask, buf, count);
+}
+
+static struct sysfs_ops mlog_attr_ops = {
+	.show  = mlog_show,
+	.store = mlog_store,
+};
+
+static struct kobj_type mlog_ktype = {
+	.default_attrs = mlog_attr_ptrs,
+	.sysfs_ops     = &mlog_attr_ops,
+};
+
+static struct kset mlog_kset = {
+	.kobj   = {.name = "logmask", .ktype = &mlog_ktype},
+};
+
+int mlog_sys_init(struct subsystem *o2cb_subsys)
+{
+	int i = 0;
+
+	while (mlog_attrs[i].attr.mode) {
+		mlog_attr_ptrs[i] = &mlog_attrs[i].attr;
+		i++;
+	}
+	mlog_attr_ptrs[i] = NULL;
+
+	mlog_kset.subsys = o2cb_subsys;
+	return kset_register(&mlog_kset);
+}
+
+void mlog_sys_shutdown(void)
+{
+	kset_unregister(&mlog_kset);
+}

fs/ocfs2/cluster/masklog.h

+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * Copyright (C) 2005 Oracle.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#ifndef O2CLUSTER_MASKLOG_H
+#define O2CLUSTER_MASKLOG_H
+
+/*
+ * For now this is a trivial wrapper around printk() that gives the critical
+ * ability to enable sets of debugging output at run-time.  In the future this
+ * will almost certainly be redirected to relayfs so that it can pay a
+ * substantially lower heisenberg tax.
+ *
+ * Callers associate the message with a bitmask and a global bitmask is
+ * maintained with help from /proc.  If any of the bits match the message is
+ * output.
+ *
+ * We must have efficient bit tests on i386 and it seems gcc still emits crazy
+ * code for the 64bit compare.  It emits very good code for the dual unsigned
+ * long tests, though, completely avoiding tests that can never pass if the
+ * caller gives a constant bitmask that fills one of the longs with all 0s.  So
+ * the desire is to have almost all of the calls decided on by comparing just
+ * one of the longs.  This leads to having infrequently given bits that are
+ * frequently matched in the high bits.
+ *
+ * _ERROR and _NOTICE are used for messages that always go to the console and
+ * have appropriate KERN_ prefixes.  We wrap these in our function instead of
+ * just calling printk() so that this can eventually make its way through
+ * relayfs along with the debugging messages.  Everything else gets KERN_DEBUG.
+ * The inline tests and macro dance give GCC the opportunity to quite cleverly
+ * only emit the appropriage printk() when the caller passes in a constant
+ * mask, as is almost always the case.
+ *
+ * All this bitmask nonsense is hidden from the /proc interface so that Joel
+ * doesn't have an aneurism.  Reading the file gives a straight forward
+ * indication of which bits are on or off:
+ * 	ENTRY off
+ * 	EXIT off
+ * 	TCP off
+ * 	MSG off
+ * 	SOCKET off
+ * 	ERROR off
+ * 	NOTICE on
+ *
+ * Writing changes the state of a given bit and requires a strictly formatted
+ * single write() call:
+ *
+ * 	write(fd, "ENTRY on", 8);
+ *
+ * would turn the entry bit on.  "1" is also accepted in the place of "on", and
+ * "off" and "0" behave as expected.
+ *
+ * Some trivial shell can flip all the bits on or off:
+ *
+ * log_mask="/proc/fs/ocfs2_nodemanager/log_mask"
+ * cat $log_mask | (
+ * 	while read bit status; do
+ * 		# $1 is "on" or "off", say
+ * 		echo "$bit $1" > $log_mask
+ * 	done
+ * )
+ */
+
+/* for task_struct */
+#include <linux/sched.h>
+
+/* bits that are frequently given and infrequently matched in the low word */
+/* NOTE: If you add a flag, you need to also update mlog.c! */
+#define ML_ENTRY	0x0000000000000001ULL /* func call entry */
+#define ML_EXIT		0x0000000000000002ULL /* func call exit */
+#define ML_TCP		0x0000000000000004ULL /* net cluster/tcp.c */
+#define ML_MSG		0x0000000000000008ULL /* net network messages */
+#define ML_SOCKET	0x0000000000000010ULL /* net socket lifetime */
+#define ML_HEARTBEAT	0x0000000000000020ULL /* hb all heartbeat tracking */
+#define ML_HB_BIO	0x0000000000000040ULL /* hb io tracing */
+#define ML_DLMFS	0x0000000000000080ULL /* dlm user dlmfs */
+#define ML_DLM		0x0000000000000100ULL /* dlm general debugging */
+#define ML_DLM_DOMAIN	0x0000000000000200ULL /* dlm domain debugging */
+#define ML_DLM_THREAD	0x0000000000000400ULL /* dlm domain thread */
+#define ML_DLM_MASTER	0x0000000000000800ULL /* dlm master functions */
+#define ML_DLM_RECOVERY	0x0000000000001000ULL /* dlm master functions */
+#define ML_AIO		0x0000000000002000ULL /* ocfs2 aio read and write */
+#define ML_JOURNAL	0x0000000000004000ULL /* ocfs2 journalling functions */
+#define ML_DISK_ALLOC	0x0000000000008000ULL /* ocfs2 disk allocation */
+#define ML_SUPER	0x0000000000010000ULL /* ocfs2 mount / umount */
+#define ML_FILE_IO	0x0000000000020000ULL /* ocfs2 file I/O */
+#define ML_EXTENT_MAP	0x0000000000040000ULL /* ocfs2 extent map caching */
+#define ML_DLM_GLUE	0x0000000000080000ULL /* ocfs2 dlm glue layer */
+#define ML_BH_IO	0x0000000000100000ULL /* ocfs2 buffer I/O */
+#define ML_UPTODATE	0x0000000000200000ULL /* ocfs2 caching sequence #'s */
+#define ML_NAMEI	0x0000000000400000ULL /* ocfs2 directory / namespace */
+#define ML_INODE	0x0000000000800000ULL /* ocfs2 inode manipulation */
+#define ML_VOTE		0x0000000001000000ULL /* ocfs2 node messaging  */
+#define ML_DCACHE	0x0000000002000000ULL /* ocfs2 dcache operations */
+#define ML_CONN		0x0000000004000000ULL /* net connection management */
+#define ML_QUORUM	0x0000000008000000ULL /* net connection quorum */
+#define ML_EXPORT	0x0000000010000000ULL /* ocfs2 export operations */
+/* bits that are infrequently given and frequently matched in the high word */
+#define ML_ERROR	0x0000000100000000ULL /* sent to KERN_ERR */
+#define ML_NOTICE	0x0000000200000000ULL /* setn to KERN_NOTICE */
+#define ML_KTHREAD	0x0000000400000000ULL /* kernel thread activity */
+
+#define MLOG_INITIAL_AND_MASK (ML_ERROR|ML_NOTICE)
+#define MLOG_INITIAL_NOT_MASK (ML_ENTRY|ML_EXIT)
+#ifndef MLOG_MASK_PREFIX
+#define MLOG_MASK_PREFIX 0
+#endif
+
+#define MLOG_MAX_BITS 64
+
+struct mlog_bits {
+	unsigned long words[MLOG_MAX_BITS / BITS_PER_LONG];
+};
+
+extern struct mlog_bits mlog_and_bits, mlog_not_bits;
+
+#if BITS_PER_LONG == 32
+
+#define __mlog_test_u64(mask, bits)			\
+	( (u32)(mask & 0xffffffff) & bits.words[0] || 	\
+	  ((u64)(mask) >> 32) & bits.words[1] )
+#define __mlog_set_u64(mask, bits) do {			\
+	bits.words[0] |= (u32)(mask & 0xffffffff);	\
+       	bits.words[1] |= (u64)(mask) >> 32;		\
+} while (0)
+#define __mlog_clear_u64(mask, bits) do {		\
+	bits.words[0] &= ~((u32)(mask & 0xffffffff));	\
+       	bits.words[1] &= ~((u64)(mask) >> 32);		\
+} while (0)
+#define MLOG_BITS_RHS(mask) {				\
+	{						\
+		[0] = (u32)(mask & 0xffffffff),		\
+		[1] = (u64)(mask) >> 32,		\
+	}						\
+}
+
+#else /* 32bit long above, 64bit long below */
+
+#define __mlog_test_u64(mask, bits)	((mask) & bits.words[0])
+#define __mlog_set_u64(mask, bits) do {		\
+	bits.words[0] |= (mask);		\
+} while (0)
+#define __mlog_clear_u64(mask, bits) do {	\
+	bits.words[0] &= ~(mask);		\
+} while (0)
+#define MLOG_BITS_RHS(mask) { { (mask) } }
+
+#endif
+
+/*
+ * smp_processor_id() "helpfully" screams when called outside preemptible
+ * regions in current kernels.  sles doesn't have the variants that don't
+ * scream.  just do this instead of trying to guess which we're building
+ * against.. *sigh*.
+ */
+#define __mlog_cpu_guess ({		\
+	unsigned long _cpu = get_cpu();	\
+	put_cpu();			\
+	_cpu;				\
+})
+
+/* In the following two macros, the whitespace after the ',' just
+ * before ##args is intentional. Otherwise, gcc 2.95 will eat the
+ * previous token if args expands to nothing.
+ */
+#define __mlog_printk(level, fmt, args...)				\
+	printk(level "(%u,%lu):%s:%d " fmt, current->pid,		\
+	       __mlog_cpu_guess, __PRETTY_FUNCTION__, __LINE__ ,	\
+	       ##args)
+
+#define mlog(mask, fmt, args...) do {					\
+	u64 __m = MLOG_MASK_PREFIX | (mask);				\
+	if (__mlog_test_u64(__m, mlog_and_bits) &&			\
+	    !__mlog_test_u64(__m, mlog_not_bits)) {			\
+		if (__m & ML_ERROR)					\
+			__mlog_printk(KERN_ERR, "ERROR: "fmt , ##args);	\
+		else if (__m & ML_NOTICE)				\
+			__mlog_printk(KERN_NOTICE, fmt , ##args);	\
+		else __mlog_printk(KERN_INFO, fmt , ##args);		\
+	}								\
+} while (0)
+
+#define mlog_errno(st) do {						\
+	int _st = (st);							\
+	if (_st != -ERESTARTSYS && _st != -EINTR &&			\
+	    _st != AOP_TRUNCATED_PAGE)					\
+		mlog(ML_ERROR, "status = %lld\n", (long long)_st);	\
+} while (0)
+
+#define mlog_entry(fmt, args...) do {					\
+	mlog(ML_ENTRY, "ENTRY:" fmt , ##args);				\
+} while (0)
+
+#define mlog_entry_void() do {						\
+	mlog(ML_ENTRY, "ENTRY:\n");					\
+} while (0)
+
+/* We disable this for old compilers since they don't have support for
+ * __builtin_types_compatible_p.
+ */
+#if (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1)) && \
+    !defined(__CHECKER__)
+#define mlog_exit(st) do {						     \
+	if (__builtin_types_compatible_p(typeof(st), unsigned long))	     \
+		mlog(ML_EXIT, "EXIT: %lu\n", (unsigned long) (st));	     \
+	else if (__builtin_types_compatible_p(typeof(st), signed long))      \
+		mlog(ML_EXIT, "EXIT: %ld\n", (signed long) (st));	     \
+	else if (__builtin_types_compatible_p(typeof(st), unsigned int)	     \
+		 || __builtin_types_compatible_p(typeof(st), unsigned short) \
+		 || __builtin_types_compatible_p(typeof(st), unsigned char)) \
+		mlog(ML_EXIT, "EXIT: %u\n", (unsigned int) (st));	     \
+	else if (__builtin_types_compatible_p(typeof(st), signed int)	     \
+		 || __builtin_types_compatible_p(typeof(st), signed short)   \
+		 || __builtin_types_compatible_p(typeof(st), signed char))   \
+		mlog(ML_EXIT, "EXIT: %d\n", (signed int) (st));		     \
+	else if (__builtin_types_compatible_p(typeof(st), long long))	     \
+		mlog(ML_EXIT, "EXIT: %lld\n", (long long) (st));	     \
+	else								     \
+		mlog(ML_EXIT, "EXIT: %llu\n", (unsigned long long) (st));    \
+} while (0)
+#else
+#define mlog_exit(st) do {						     \
+	mlog(ML_EXIT, "EXIT: %lld\n", (long long) (st));		     \
+} while (0)
+#endif
+
+#define mlog_exit_ptr(ptr) do {						\
+	mlog(ML_EXIT, "EXIT: %p\n", ptr);				\
+} while (0)
+
+#define mlog_exit_void() do {						\
+	mlog(ML_EXIT, "EXIT\n");					\
+} while (0)
+
+#define mlog_bug_on_msg(cond, fmt, args...) do {			\
+	if (cond) {							\
+		mlog(ML_ERROR, "bug expression: " #cond "\n");		\
+		mlog(ML_ERROR, fmt, ##args);				\
+		BUG();							\
+	}								\
+} while (0)
+
+#if (BITS_PER_LONG == 32) || defined(CONFIG_X86_64)
+#define MLFi64 "lld"
+#define MLFu64 "llu"
+#define MLFx64 "llx"
+#else
+#define MLFi64 "ld"
+#define MLFu64 "lu"
+#define MLFx64 "lx"
+#endif
+
+#include <linux/kobject.h>
+#include <linux/sysfs.h>
+int mlog_sys_init(struct subsystem *o2cb_subsys);
+void mlog_sys_shutdown(void);
+
+#endif /* O2CLUSTER_MASKLOG_H */