3598 want to dtrace when errors are generated in zfs

Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Approved by: Garrett D'Amore <garrett@damore.org>

usr/src/lib/libzpool/Makefile.com

@@ -20,7 +20,7 @@
 #
 #
 # Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
-# Copyright (c) 2012 by Delphix. All rights reserved.
+# Copyright (c) 2013 by Delphix. All rights reserved.
 #
 
 LIBRARY= libzpool.a
@@ -29,6 +29,7 @@ VERS= .1
 # include the list of ZFS sources
 include ../../../uts/common/Makefile.files
 KERNEL_OBJS = kernel.o taskq.o util.o
+DTRACE_OBJS = zfs.o
 
 OBJECTS=$(ZFS_COMMON_OBJS) $(ZFS_SHARED_OBJS) $(KERNEL_OBJS)
 
@@ -52,7 +53,10 @@ INCS += -I../../../uts/common/fs/zfs
 INCS += -I../../../common/zfs
 INCS += -I../../../common
 
+CLEANFILES += ../common/zfs.h
+
 $(LINTLIB) := SRCS=	$(SRCDIR)/$(LINTSRC)
+$(LINTLIB): ../common/zfs.h
 
 C99MODE=	-xc99=%all
 C99LMODE=	-Xc99=%all
@@ -79,10 +83,19 @@ lint: $(LINTLIB)
 
 include ../../Makefile.targ
 
-pics/%.o: ../../../uts/common/fs/zfs/%.c
+EXTPICS= $(DTRACE_OBJS:%=pics/%)
+
+pics/%.o: ../../../uts/common/fs/zfs/%.c ../common/zfs.h
 	$(COMPILE.c) -o $@ $<
 	$(POST_PROCESS_O)
 
-pics/%.o: ../../../common/zfs/%.c
+pics/%.o: ../../../common/zfs/%.c ../common/zfs.h
 	$(COMPILE.c) -o $@ $<
 	$(POST_PROCESS_O)
+
+pics/%.o: ../common/%.d $(PICS)
+	$(COMPILE.d) -C -s $< -o $@ $(PICS)
+	$(POST_PROCESS_O)
+
+../common/%.h: ../common/%.d
+	$(DTRACE) -xnolibs -h -s $< -o $@

usr/src/lib/libzpool/common/sys/zfs_context.h

@@ -21,7 +21,7 @@
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
- * Copyright (c) 2012 by Delphix. All rights reserved.
+ * Copyright (c) 2013 by Delphix. All rights reserved.
  * Copyright (c) 2012, Joyent, Inc. All rights reserved.
  */
 
@@ -81,6 +81,7 @@ extern "C" {
 #include <sys/sysevent/dev.h>
 #include <sys/sunddi.h>
 #include <sys/debug.h>
+#include "zfs.h"
 
 /*
  * Debugging
@@ -121,28 +122,43 @@ extern int aok;
 
 #ifdef DTRACE_PROBE
 #undef	DTRACE_PROBE
-#define	DTRACE_PROBE(a)	((void)0)
 #endif	/* DTRACE_PROBE */
+#define	DTRACE_PROBE(a) \
+	ZFS_PROBE0(#a)
 
 #ifdef DTRACE_PROBE1
 #undef	DTRACE_PROBE1
-#define	DTRACE_PROBE1(a, b, c)	((void)0)
 #endif	/* DTRACE_PROBE1 */
+#define	DTRACE_PROBE1(a, b, c) \
+	ZFS_PROBE1(#a, (unsigned long)c)
 
 #ifdef DTRACE_PROBE2
 #undef	DTRACE_PROBE2
-#define	DTRACE_PROBE2(a, b, c, d, e)	((void)0)
 #endif	/* DTRACE_PROBE2 */
+#define	DTRACE_PROBE2(a, b, c, d, e) \
+	ZFS_PROBE2(#a, (unsigned long)c, (unsigned long)e)
 
 #ifdef DTRACE_PROBE3
 #undef	DTRACE_PROBE3
-#define	DTRACE_PROBE3(a, b, c, d, e, f, g)	((void)0)
 #endif	/* DTRACE_PROBE3 */
+#define	DTRACE_PROBE3(a, b, c, d, e, f, g) \
+	ZFS_PROBE3(#a, (unsigned long)c, (unsigned long)e, (unsigned long)g)
 
 #ifdef DTRACE_PROBE4
 #undef	DTRACE_PROBE4
-#define	DTRACE_PROBE4(a, b, c, d, e, f, g, h, i)	((void)0)
 #endif	/* DTRACE_PROBE4 */
+#define	DTRACE_PROBE4(a, b, c, d, e, f, g, h, i) \
+	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

usr/src/lib/libzpool/common/zfs.d

@@ -0,0 +1,36 @@
+/*
+ * CDDL HEADER START
+ *
+ * This file and its contents are supplied under the terms of the
+ * Common Development and Distribution License ("CDDL"), version 1.0.
+ * You may only use this file in accordance with the terms of version
+ * 1.0 of the CDDL.
+ *
+ * A full copy of the text of the CDDL should have accompanied this
+ * source.  A copy of the CDDL is also available via the Internet at
+ * http://www.illumos.org/license/CDDL.
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright (c) 2013 by Delphix. All rights reserved.
+ */
+
+provider zfs {
+	probe probe0(char *probename);
+	probe probe1(char *probename, unsigned long arg1);
+	probe probe2(char *probename, unsigned long arg1, unsigned long arg2);
+	probe probe3(char *probename, unsigned long arg1, unsigned long arg2,
+	    unsigned long arg3);
+	probe probe4(char *probename, unsigned long arg1, unsigned long arg2,
+	    unsigned long arg3, unsigned long arg4);
+
+	probe set__error(int err);
+};
+
+#pragma D attributes Evolving/Evolving/ISA provider zfs provider
+#pragma D attributes Private/Private/Unknown provider zfs module
+#pragma D attributes Private/Private/Unknown provider zfs function
+#pragma D attributes Evolving/Evolving/ISA provider zfs name
+#pragma D attributes Evolving/Evolving/ISA provider zfs args

usr/src/uts/common/fs/zfs/arc.c

@@ -21,7 +21,7 @@
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
- * Copyright (c) 2012 by Delphix. All rights reserved.
+ * Copyright (c) 2013 by Delphix. All rights reserved.
  */
 
 /*
@@ -3466,14 +3466,14 @@ arc_memory_throttle(uint64_t reserve, uint64_t inflight_data, uint64_t txg)
 	 */
 	if (curproc == proc_pageout) {
 		if (page_load > MAX(ptob(minfree), available_memory) / 4)
-			return (ERESTART);
+			return (SET_ERROR(ERESTART));
 		/* Note: reserve is inflated, so we deflate */
 		page_load += reserve / 8;
 		return (0);
 	} else if (page_load > 0 && arc_reclaim_needed()) {
 		/* memory is low, delay before restarting */
 		ARCSTAT_INCR(arcstat_memory_throttle_count, 1);
-		return (EAGAIN);
+		return (SET_ERROR(EAGAIN));
 	}
 	page_load = 0;
 
@@ -3488,7 +3488,7 @@ arc_memory_throttle(uint64_t reserve, uint64_t inflight_data, uint64_t txg)
 
 	if (inflight_data > available_memory / 4) {
 		ARCSTAT_INCR(arcstat_memory_throttle_count, 1);
-		return (ERESTART);
+		return (SET_ERROR(ERESTART));
 	}
 #endif
 	return (0);
@@ -3513,13 +3513,13 @@ arc_tempreserve_space(uint64_t reserve, uint64_t txg)
 	 */
 	if (spa_get_random(10000) == 0) {
 		dprintf("forcing random failure\n");
-		return (ERESTART);
+		return (SET_ERROR(ERESTART));
 	}
 #endif
 	if (reserve > arc_c/4 && !arc_no_grow)
 		arc_c = MIN(arc_c_max, reserve * 4);
 	if (reserve > arc_c)
-		return (ENOMEM);
+		return (SET_ERROR(ENOMEM));
 
 	/*
 	 * Don't count loaned bufs as in flight dirty data to prevent long
@@ -3552,7 +3552,7 @@ arc_tempreserve_space(uint64_t reserve, uint64_t txg)
 		    arc_anon->arcs_lsize[ARC_BUFC_METADATA]>>10,
 		    arc_anon->arcs_lsize[ARC_BUFC_DATA]>>10,
 		    reserve>>10, arc_c>>10);
-		return (ERESTART);
+		return (SET_ERROR(ERESTART));
 	}
 	atomic_add_64(&arc_tempreserve, reserve);
 	return (0);
@@ -4145,7 +4145,7 @@ l2arc_read_done(zio_t *zio)
 		if (zio->io_error != 0) {
 			ARCSTAT_BUMP(arcstat_l2_io_error);
 		} else {
-			zio->io_error = EIO;
+			zio->io_error = SET_ERROR(EIO);
 		}
 		if (!equal)
 			ARCSTAT_BUMP(arcstat_l2_cksum_bad);

usr/src/uts/common/fs/zfs/dbuf.c

@@ -21,7 +21,7 @@
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
- * Copyright (c) 2012 by Delphix. All rights reserved.
+ * Copyright (c) 2013 by Delphix. All rights reserved.
  */
 
 #include <sys/zfs_context.h>
@@ -598,7 +598,7 @@ dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags)
 	ASSERT(!refcount_is_zero(&db->db_holds));
 
 	if (db->db_state == DB_NOFILL)
-		return (EIO);
+		return (SET_ERROR(EIO));
 
 	DB_DNODE_ENTER(db);
 	dn = DB_DNODE(db);
@@ -655,7 +655,7 @@ dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags)
 				cv_wait(&db->db_changed, &db->db_mtx);
 			}
 			if (db->db_state == DB_UNCACHED)
-				err = EIO;
+				err = SET_ERROR(EIO);
 		}
 		mutex_exit(&db->db_mtx);
 	}
@@ -1593,7 +1593,7 @@ dbuf_findbp(dnode_t *dn, int level, uint64_t blkid, int fail_sparse,
 	if (level >= nlevels ||
 	    (blkid > (dn->dn_phys->dn_maxblkid >> (level * epbs)))) {
 		/* the buffer has no parent yet */
-		return (ENOENT);
+		return (SET_ERROR(ENOENT));
 	} else if (level < nlevels-1) {
 		/* this block is referenced from an indirect block */
 		int err = dbuf_hold_impl(dn, level+1,
@@ -1844,7 +1844,7 @@ dbuf_hold_impl(dnode_t *dn, uint8_t level, uint64_t blkid, int fail_sparse,
 		err = dbuf_findbp(dn, level, blkid, fail_sparse, &parent, &bp);
 		if (fail_sparse) {
 			if (err == 0 && bp && BP_IS_HOLE(bp))
-				err = ENOENT;
+				err = SET_ERROR(ENOENT);
 			if (err) {
 				if (parent)
 					dbuf_rele(parent, NULL);
@@ -1941,7 +1941,7 @@ dbuf_spill_set_blksz(dmu_buf_t *db_fake, uint64_t blksz, dmu_tx_t *tx)
 	dnode_t *dn;
 
 	if (db->db_blkid != DMU_SPILL_BLKID)
-		return (ENOTSUP);
+		return (SET_ERROR(ENOTSUP));
 	if (blksz == 0)
 		blksz = SPA_MINBLOCKSIZE;
 	if (blksz > SPA_MAXBLOCKSIZE)

usr/src/uts/common/fs/zfs/ddt.c

@@ -21,7 +21,7 @@
 
 /*
  * Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2012 by Delphix. All rights reserved.
+ * Copyright (c) 2013 by Delphix. All rights reserved.
  */
 
 #include <sys/zfs_context.h>
@@ -160,7 +160,7 @@ ddt_object_lookup(ddt_t *ddt, enum ddt_type type, enum ddt_class class,
     ddt_entry_t *dde)
 {
 	if (!ddt_object_exists(ddt, type, class))
-		return (ENOENT);
+		return (SET_ERROR(ENOENT));
 
 	return (ddt_ops[type]->ddt_op_lookup(ddt->ddt_os,
 	    ddt->ddt_object[type][class], dde));
@@ -221,7 +221,7 @@ ddt_object_info(ddt_t *ddt, enum ddt_type type, enum ddt_class class,
     dmu_object_info_t *doi)
 {
 	if (!ddt_object_exists(ddt, type, class))
-		return (ENOENT);
+		return (SET_ERROR(ENOENT));
 
 	return (dmu_object_info(ddt->ddt_os, ddt->ddt_object[type][class],
 	    doi));
@@ -1141,5 +1141,5 @@ ddt_walk(spa_t *spa, ddt_bookmark_t *ddb, ddt_entry_t *dde)
 		ddb->ddb_type = 0;
 	} while (++ddb->ddb_class < DDT_CLASSES);
 
-	return (ENOENT);
+	return (SET_ERROR(ENOENT));
 }