Merge branch 'b_tracepoints'

Signed-off-by: Prakash Surya <[email protected]>
Signed-off-by: Ned Bass <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>
Closes #2874

10 files changed, 181 insertions, 221 deletions

diff --git a/module/zfs/Makefile.in b/module/zfs/Makefile.in
index 48e7e97e9..954841f33 100644
--- a/module/zfs/Makefile.in
+++ b/module/zfs/Makefile.in
@@ -52,6 +52,7 @@ $(MODULE)-objs += @top_srcdir@/module/zfs/spa_stats.o
 $(MODULE)-objs += @top_srcdir@/module/zfs/space_map.o
 $(MODULE)-objs += @top_srcdir@/module/zfs/space_reftree.o
 $(MODULE)-objs += @top_srcdir@/module/zfs/txg.o
+$(MODULE)-objs += @top_srcdir@/module/zfs/trace.o
 $(MODULE)-objs += @top_srcdir@/module/zfs/uberblock.o
 $(MODULE)-objs += @top_srcdir@/module/zfs/unique.o
 $(MODULE)-objs += @top_srcdir@/module/zfs/vdev.o
diff --git a/module/zfs/arc.c b/module/zfs/arc.c
index 0742da0f6..fd593a13e 100644
--- a/module/zfs/arc.c
+++ b/module/zfs/arc.c
@@ -145,6 +145,7 @@
 #include <sys/kstat.h>
 #include <sys/dmu_tx.h>
 #include <zfs_fletcher.h>
+#include <sys/arc_impl.h>
 
 #ifndef _KERNEL
 /* set with ZFS_DEBUG=watch, to enable watchpoints on frozen buffers */
@@ -218,46 +219,6 @@ unsigned long zfs_arc_max = 0;
 unsigned long zfs_arc_min = 0;
 unsigned long zfs_arc_meta_limit = 0;
 
-/*
- * Note that buffers can be in one of 6 states:
- *	ARC_anon	- anonymous (discussed below)
- *	ARC_mru		- recently used, currently cached
- *	ARC_mru_ghost	- recentely used, no longer in cache
- *	ARC_mfu		- frequently used, currently cached
- *	ARC_mfu_ghost	- frequently used, no longer in cache
- *	ARC_l2c_only	- exists in L2ARC but not other states
- * When there are no active references to the buffer, they are
- * are linked onto a list in one of these arc states.  These are
- * the only buffers that can be evicted or deleted.  Within each
- * state there are multiple lists, one for meta-data and one for
- * non-meta-data.  Meta-data (indirect blocks, blocks of dnodes,
- * etc.) is tracked separately so that it can be managed more
- * explicitly: favored over data, limited explicitly.
- *
- * Anonymous buffers are buffers that are not associated with
- * a DVA.  These are buffers that hold dirty block copies
- * before they are written to stable storage.  By definition,
- * they are "ref'd" and are considered part of arc_mru
- * that cannot be freed.  Generally, they will aquire a DVA
- * as they are written and migrate onto the arc_mru list.
- *
- * The ARC_l2c_only state is for buffers that are in the second
- * level ARC but no longer in any of the ARC_m* lists.  The second
- * level ARC itself may also contain buffers that are in any of
- * the ARC_m* states - meaning that a buffer can exist in two
- * places.  The reason for the ARC_l2c_only state is to keep the
- * buffer header in the hash table, so that reads that hit the
- * second level ARC benefit from these fast lookups.
- */
-
-typedef struct arc_state {
-	list_t	arcs_list[ARC_BUFC_NUMTYPES];	/* list of evictable buffers */
-	uint64_t arcs_lsize[ARC_BUFC_NUMTYPES];	/* amount of evictable data */
-	uint64_t arcs_size;	/* total amount of data in this state */
-	kmutex_t arcs_mtx;
-	arc_state_type_t arcs_state;
-} arc_state_t;
-
 /* The 6 states: */
 static arc_state_t ARC_anon;
 static arc_state_t ARC_mru;
@@ -522,69 +483,6 @@ static arc_state_t	*arc_l2c_only;
 #define	L2ARC_IS_VALID_COMPRESS(_c_) \
 	((_c_) == ZIO_COMPRESS_LZ4 || (_c_) == ZIO_COMPRESS_EMPTY)
 
-typedef struct l2arc_buf_hdr l2arc_buf_hdr_t;
-
-typedef struct arc_callback arc_callback_t;
-
-struct arc_callback {
-	void			*acb_private;
-	arc_done_func_t		*acb_done;
-	arc_buf_t		*acb_buf;
-	zio_t			*acb_zio_dummy;
-	arc_callback_t		*acb_next;
-};
-
-typedef struct arc_write_callback arc_write_callback_t;
-
-struct arc_write_callback {
-	void		*awcb_private;
-	arc_done_func_t	*awcb_ready;
-	arc_done_func_t	*awcb_physdone;
-	arc_done_func_t	*awcb_done;
-	arc_buf_t	*awcb_buf;
-};
-
-struct arc_buf_hdr {
-	/* protected by hash lock */
-	dva_t			b_dva;
-	uint64_t		b_birth;
-	uint64_t		b_cksum0;
-
-	kmutex_t		b_freeze_lock;
-	zio_cksum_t		*b_freeze_cksum;
-
-	arc_buf_hdr_t		*b_hash_next;
-	arc_buf_t		*b_buf;
-	uint32_t		b_flags;
-	uint32_t		b_datacnt;
-
-	arc_callback_t		*b_acb;
-	kcondvar_t		b_cv;
-
-	/* immutable */
-	arc_buf_contents_t	b_type;
-	uint64_t		b_size;
-	uint64_t		b_spa;
-
-	/* protected by arc state mutex */
-	arc_state_t		*b_state;
-	list_node_t		b_arc_node;
-
-	/* updated atomically */
-	clock_t			b_arc_access;
-	uint32_t		b_mru_hits;
-	uint32_t		b_mru_ghost_hits;
-	uint32_t		b_mfu_hits;
-	uint32_t		b_mfu_ghost_hits;
-	uint32_t		b_l2_hits;
-
-	/* self protecting */
-	refcount_t		b_refcnt;
-
-	l2arc_buf_hdr_t		*b_l2hdr;
-	list_node_t		b_l2node;
-};
-
 static list_t arc_prune_list;
 static kmutex_t arc_prune_mtx;
 static arc_buf_t *arc_eviction_list;
@@ -707,19 +605,6 @@ int l2arc_norw = B_FALSE;			/* no reads during writes */
 /*
  * L2ARC Internals
  */
-typedef struct l2arc_dev {
-	vdev_t			*l2ad_vdev;	/* vdev */
-	spa_t			*l2ad_spa;	/* spa */
-	uint64_t		l2ad_hand;	/* next write location */
-	uint64_t		l2ad_start;	/* first addr on device */
-	uint64_t		l2ad_end;	/* last addr on device */
-	uint64_t		l2ad_evict;	/* last addr eviction reached */
-	boolean_t		l2ad_first;	/* first sweep through */
-	boolean_t		l2ad_writing;	/* currently writing */
-	list_t			*l2ad_buflist;	/* buffer list */
-	list_node_t		l2ad_node;	/* device list node */
-} l2arc_dev_t;
-
 static list_t L2ARC_dev_list;			/* device list */
 static list_t *l2arc_dev_list;			/* device list pointer */
 static kmutex_t l2arc_dev_mtx;			/* device list mutex */
@@ -2043,7 +1928,7 @@ top:
 
 	if (bytes_evicted < bytes)
 		dprintf("only evicted %lld bytes from %x\n",
-		    (longlong_t)bytes_evicted, state);
+		    (longlong_t)bytes_evicted, state->arcs_state);
 
 	if (skipped)
 		ARCSTAT_INCR(arcstat_evict_skip, skipped);
diff --git a/module/zfs/bptree.c b/module/zfs/bptree.c
index 61fa17f6e..0eafa4d7d 100644
--- a/module/zfs/bptree.c
+++ b/module/zfs/bptree.c
@@ -221,7 +221,7 @@ bptree_iterate(objset_t *os, uint64_t obj, boolean_t free, bptree_itor_t func,
 
 		if (zfs_free_leak_on_eio)
 			flags |= TRAVERSE_HARD;
-		zfs_dbgmsg("bptree index %d: traversing from min_txg=%lld "
+		zfs_dbgmsg("bptree index %lld: traversing from min_txg=%lld "
 		    "bookmark %lld/%lld/%lld/%lld",
 		    i, (longlong_t)bte.be_birth_txg,
 		    (longlong_t)bte.be_zb.zb_objset,
diff --git a/module/zfs/spa_misc.c b/module/zfs/spa_misc.c
index bb740e569..2d16d7e06 100644
--- a/module/zfs/spa_misc.c
+++ b/module/zfs/spa_misc.c
@@ -238,6 +238,53 @@ static avl_tree_t spa_l2cache_avl;
 kmem_cache_t *spa_buffer_pool;
 int spa_mode_global;
 
+#ifdef ZFS_DEBUG
+/* Everything except dprintf and spa is on by default in debug builds */
+int zfs_flags = ~(ZFS_DEBUG_DPRINTF | ZFS_DEBUG_SPA);
+#else
+int zfs_flags = 0;
+#endif
+
+/*
+ * zfs_recover can be set to nonzero to attempt to recover from
+ * otherwise-fatal errors, typically caused by on-disk corruption.  When
+ * set, calls to zfs_panic_recover() will turn into warning messages.
+ * This should only be used as a last resort, as it typically results
+ * in leaked space, or worse.
+ */
+int zfs_recover = B_FALSE;
+
+/*
+ * If destroy encounters an EIO while reading metadata (e.g. indirect
+ * blocks), space referenced by the missing metadata can not be freed.
+ * Normally this causes the background destroy to become "stalled", as
+ * it is unable to make forward progress.  While in this stalled state,
+ * all remaining space to free from the error-encountering filesystem is
+ * "temporarily leaked".  Set this flag to cause it to ignore the EIO,
+ * permanently leak the space from indirect blocks that can not be read,
+ * and continue to free everything else that it can.
+ *
+ * The default, "stalling" behavior is useful if the storage partially
+ * fails (i.e. some but not all i/os fail), and then later recovers.  In
+ * this case, we will be able to continue pool operations while it is
+ * partially failed, and when it recovers, we can continue to free the
+ * space, with no leaks.  However, note that this case is actually
+ * fairly rare.
+ *
+ * Typically pools either (a) fail completely (but perhaps temporarily,
+ * e.g. a top-level vdev going offline), or (b) have localized,
+ * permanent errors (e.g. disk returns the wrong data due to bit flip or
+ * firmware bug).  In case (a), this setting does not matter because the
+ * pool will be suspended and the sync thread will not be able to make
+ * forward progress regardless.  In case (b), because the error is
+ * permanent, the best we can do is leak the minimum amount of space,
+ * which is what setting this flag will do.  Therefore, it is reasonable
+ * for this flag to normally be set, but we chose the more conservative
+ * approach of not setting it, so that there is no possibility of
+ * leaking space in the "partial temporary" failure case.
+ */
+int zfs_free_leak_on_eio = B_FALSE;
+
 /*
  * Expiration time in milliseconds. This value has two meanings. First it is
  * used to determine when the spa_deadman() logic should fire. By default the
@@ -1319,6 +1366,16 @@ spa_freeze(spa_t *spa)
 		txg_wait_synced(spa_get_dsl(spa), freeze_txg);
 }
 
+void
+zfs_panic_recover(const char *fmt, ...)
+{
+	va_list adx;
+
+	va_start(adx, fmt);
+	vcmn_err(zfs_recover ? CE_WARN : CE_PANIC, fmt, adx);
+	va_end(adx);
+}
+
 /*
  * This is a stripped-down version of strtoull, suitable only for converting
  * lowercase hexadecimal numbers that don't overflow.
@@ -1923,6 +1980,16 @@ EXPORT_SYMBOL(spa_mode);
 
 EXPORT_SYMBOL(spa_namespace_lock);
 
+module_param(zfs_flags, int, 0644);
+MODULE_PARM_DESC(zfs_flags, "Set additional debugging flags");
+
+module_param(zfs_recover, int, 0644);
+MODULE_PARM_DESC(zfs_recover, "Set to attempt to recover from fatal errors");
+
+module_param(zfs_free_leak_on_eio, int, 0644);
+MODULE_PARM_DESC(zfs_free_leak_on_eio,
+	"Set to ignore IO errors during free and permanently leak the space");
+
 module_param(zfs_deadman_synctime_ms, ulong, 0644);
 MODULE_PARM_DESC(zfs_deadman_synctime_ms, "Expiration time in milliseconds");
 
diff --git a/module/zfs/space_map.c b/module/zfs/space_map.c
index 0ceccf669..fc0df756e 100644
--- a/module/zfs/space_map.c
+++ b/module/zfs/space_map.c
@@ -427,7 +427,7 @@ space_map_truncate(space_map_t *sm, dmu_tx_t *tx)
 	    doi.doi_bonus_size != sizeof (space_map_phys_t)) ||
 	    doi.doi_data_block_size != space_map_blksz) {
 		zfs_dbgmsg("txg %llu, spa %s, reallocating: "
-		    "old bonus %u, old blocksz %u", dmu_tx_get_txg(tx),
+		    "old bonus %llu, old blocksz %u", dmu_tx_get_txg(tx),
 		    spa_name(spa), doi.doi_bonus_size, doi.doi_data_block_size);
 
 		space_map_free(sm, tx);
diff --git a/module/zfs/trace.c b/module/zfs/trace.c
new file mode 100644
index 000000000..54ca2b2b4
--- /dev/null
+++ b/module/zfs/trace.c
@@ -0,0 +1,39 @@
+/*
+ * 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
+ */
+/*
+ * Each Linux tracepoints subsystem must define CREATE_TRACE_POINTS in one
+ * (and only one) C file, so this dummy file exists for that purpose.
+ */
+
+#include <sys/arc_impl.h>
+#include <sys/vdev_impl.h>
+#include <sys/zio.h>
+#include <sys/dbuf.h>
+#include <sys/dmu_objset.h>
+#include <sys/dsl_dataset.h>
+#include <sys/dmu_tx.h>
+#include <sys/dnode.h>
+#include <sys/zfs_znode.h>
+#include <sys/zil_impl.h>
+#include <sys/zrlock.h>
+
+#define	CREATE_TRACE_POINTS
+#include <sys/trace.h>
diff --git a/module/zfs/zap.c b/module/zfs/zap.c
index 02c92748f..4ee75b6d9 100644
--- a/module/zfs/zap.c
+++ b/module/zfs/zap.c
@@ -209,7 +209,7 @@ zap_table_grow(zap_t *zap, zap_table_phys_t *tbl,
 		tbl->zt_nextblk = 0;
 		tbl->zt_blks_copied = 0;
 
-		dprintf("finished; numblocks now %llu (%lluk entries)\n",
+		dprintf("finished; numblocks now %llu (%uk entries)\n",
 		    tbl->zt_numblks, 1<<(tbl->zt_shift-10));
 	}
 
diff --git a/module/zfs/zfs_debug.c b/module/zfs/zfs_debug.c
index e7f266b5f..e1675c818 100644
--- a/module/zfs/zfs_debug.c
+++ b/module/zfs/zfs_debug.c
@@ -25,99 +25,22 @@
 
 #include <sys/zfs_context.h>
 
-#if !defined(_KERNEL) || !defined(__linux__)
 list_t zfs_dbgmsgs;
 int zfs_dbgmsg_size;
 kmutex_t zfs_dbgmsgs_lock;
 int zfs_dbgmsg_maxsize = 4<<20; /* 4MB */
-#endif
 
-/*
- * Enable various debugging features.
- */
-int zfs_flags = 0;
-
-/*
- * zfs_recover can be set to nonzero to attempt to recover from
- * otherwise-fatal errors, typically caused by on-disk corruption.  When
- * set, calls to zfs_panic_recover() will turn into warning messages.
- * This should only be used as a last resort, as it typically results
- * in leaked space, or worse.
- */
-int zfs_recover = B_FALSE;
-
-/*
- * If destroy encounters an EIO while reading metadata (e.g. indirect
- * blocks), space referenced by the missing metadata can not be freed.
- * Normally this causes the background destroy to become "stalled", as
- * it is unable to make forward progress.  While in this stalled state,
- * all remaining space to free from the error-encountering filesystem is
- * "temporarily leaked".  Set this flag to cause it to ignore the EIO,
- * permanently leak the space from indirect blocks that can not be read,
- * and continue to free everything else that it can.
- *
- * The default, "stalling" behavior is useful if the storage partially
- * fails (i.e. some but not all i/os fail), and then later recovers.  In
- * this case, we will be able to continue pool operations while it is
- * partially failed, and when it recovers, we can continue to free the
- * space, with no leaks.  However, note that this case is actually
- * fairly rare.
- *
- * Typically pools either (a) fail completely (but perhaps temporarily,
- * e.g. a top-level vdev going offline), or (b) have localized,
- * permanent errors (e.g. disk returns the wrong data due to bit flip or
- * firmware bug).  In case (a), this setting does not matter because the
- * pool will be suspended and the sync thread will not be able to make
- * forward progress regardless.  In case (b), because the error is
- * permanent, the best we can do is leak the minimum amount of space,
- * which is what setting this flag will do.  Therefore, it is reasonable
- * for this flag to normally be set, but we chose the more conservative
- * approach of not setting it, so that there is no possibility of
- * leaking space in the "partial temporary" failure case.
- */
-int zfs_free_leak_on_eio = B_FALSE;
-
-
-void
-zfs_panic_recover(const char *fmt, ...)
-{
-	va_list adx;
-
-	va_start(adx, fmt);
-	vcmn_err(zfs_recover ? CE_WARN : CE_PANIC, fmt, adx);
-	va_end(adx);
-}
-
-/*
- * Debug logging is enabled by default for production kernel builds.
- * The overhead for this is negligible and the logs can be valuable when
- * debugging.  For non-production user space builds all debugging except
- * logging is enabled since performance is no longer a concern.
- */
 void
 zfs_dbgmsg_init(void)
 {
-#if !defined(_KERNEL) || !defined(__linux__)
 	list_create(&zfs_dbgmsgs, sizeof (zfs_dbgmsg_t),
 	    offsetof(zfs_dbgmsg_t, zdm_node));
 	mutex_init(&zfs_dbgmsgs_lock, NULL, MUTEX_DEFAULT, NULL);
-#endif
-
-	if (zfs_flags == 0) {
-#if defined(_KERNEL)
-		zfs_flags = ZFS_DEBUG_DPRINTF;
-		spl_debug_set_mask(spl_debug_get_mask() | SD_DPRINTF);
-		spl_debug_set_subsys(spl_debug_get_subsys() | SS_USER1);
-#else
-		zfs_flags = ~ZFS_DEBUG_DPRINTF;
-#endif /* _KERNEL */
-	}
 }
 
 void
 zfs_dbgmsg_fini(void)
 {
-#if !defined(_KERNEL) || !defined(__linux__)
 	zfs_dbgmsg_t *zdm;
 
 	while ((zdm = list_remove_head(&zfs_dbgmsgs)) != NULL) {
@@ -127,25 +50,24 @@ zfs_dbgmsg_fini(void)
 	}
 	mutex_destroy(&zfs_dbgmsgs_lock);
 	ASSERT0(zfs_dbgmsg_size);
-#endif
 }
 
-#if !defined(_KERNEL) || !defined(__linux__)
 /*
- * Print these messages by running:
- * echo ::zfs_dbgmsg | mdb -k
+ * To get this data enable the zfs__dbgmsg tracepoint as shown:
  *
- * Monitor these messages by running:
- * dtrace -qn 'zfs-dbgmsg{printf("%s\n", stringof(arg0))}'
+ * # Enable zfs__dbgmsg tracepoint, clear the tracepoint ring buffer
+ * $ echo 1 > /sys/kernel/debug/tracing/events/zfs/enable
+ * $ echo 0 > /sys/kernel/debug/tracing/trace
  *
- * When used with libzpool, monitor with:
- * dtrace -qn 'zfs$pid::zfs_dbgmsg:probe1{printf("%s\n", copyinstr(arg1))}'
+ * # Dump the ring buffer.
+ * $ cat /sys/kernel/debug/tracing/trace
  */
 void
 zfs_dbgmsg(const char *fmt, ...)
 {
 	int size;
 	va_list adx;
+	char *nl;
 	zfs_dbgmsg_t *zdm;
 
 	va_start(adx, fmt);
@@ -156,13 +78,20 @@ zfs_dbgmsg(const char *fmt, ...)
 	 * There is one byte of string in sizeof (zfs_dbgmsg_t), used
 	 * for the terminating null.
 	 */
-	zdm = kmem_alloc(sizeof (zfs_dbgmsg_t) + size, KM_SLEEP);
+	zdm = kmem_alloc(sizeof (zfs_dbgmsg_t) + size, KM_PUSHPAGE);
 	zdm->zdm_timestamp = gethrestime_sec();
 
 	va_start(adx, fmt);
 	(void) vsnprintf(zdm->zdm_msg, size + 1, fmt, adx);
 	va_end(adx);
 
+	/*
+	 * Get rid of trailing newline.
+	 */
+	nl = strrchr(zdm->zdm_msg, '\n');
+	if (nl != NULL)
+		*nl = '\0';
+
 	DTRACE_PROBE1(zfs__dbgmsg, char *, zdm->zdm_msg);
 
 	mutex_enter(&zfs_dbgmsgs_lock);
@@ -180,6 +109,7 @@ zfs_dbgmsg(const char *fmt, ...)
 void
 zfs_dbgmsg_print(const char *tag)
 {
+#if !defined(_KERNEL)
 	zfs_dbgmsg_t *zdm;
 
 	(void) printf("ZFS_DBGMSG(%s):\n", tag);
@@ -188,17 +118,5 @@ zfs_dbgmsg_print(const char *tag)
 	    zdm = list_next(&zfs_dbgmsgs, zdm))
 		(void) printf("%s\n", zdm->zdm_msg);
 	mutex_exit(&zfs_dbgmsgs_lock);
+#endif /* !_KERNEL */
 }
-#endif
-
-#if defined(_KERNEL)
-module_param(zfs_flags, int, 0644);
-MODULE_PARM_DESC(zfs_flags, "Set additional debugging flags");
-
-module_param(zfs_recover, int, 0644);
-MODULE_PARM_DESC(zfs_recover, "Set to attempt to recover from fatal errors");
-
-module_param(zfs_free_leak_on_eio, int, 0644);
-MODULE_PARM_DESC(zfs_free_leak_on_eio,
-	"Set to ignore IO errors during free and permanently leak the space");
-#endif /* _KERNEL */
diff --git a/module/zfs/zfs_ioctl.c b/module/zfs/zfs_ioctl.c
index 37a893c47..9396d6caa 100644
--- a/module/zfs/zfs_ioctl.c
+++ b/module/zfs/zfs_ioctl.c
@@ -247,6 +247,55 @@ static int zfs_fill_zplprops_root(uint64_t, nvlist_t *, nvlist_t *,
 int zfs_set_prop_nvlist(const char *, zprop_source_t, nvlist_t *, nvlist_t *);
 static int get_nvlist(uint64_t nvl, uint64_t size, int iflag, nvlist_t **nvp);
 
+#if defined(HAVE_DECLARE_EVENT_CLASS)
+void
+__dprintf(const char *file, const char *func, int line, const char *fmt, ...)
+{
+	const char *newfile;
+	size_t size = 4096;
+	char *buf = kmem_alloc(size, KM_PUSHPAGE);
+	char *nl;
+	va_list adx;
+
+	/*
+	 * Get rid of annoying prefix to filename.
+	 */
+	newfile = strrchr(file, '/');
+	if (newfile != NULL) {
+		newfile = newfile + 1; /* Get rid of leading / */
+	} else {
+		newfile = file;
+	}
+
+	va_start(adx, fmt);
+	(void) vsnprintf(buf, size, fmt, adx);
+	va_end(adx);
+
+	/*
+	 * Get rid of trailing newline.
+	 */
+	nl = strrchr(buf, '\n');
+	if (nl != NULL)
+		*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/module/zfs/parameters/zfs_flags
+	 * $ 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_PROBE4(zfs__dprintf,
+	    char *, newfile, char *, func, int, line, char *, buf);
+
+	kmem_free(buf, size);
+}
+#endif /* HAVE_DECLARE_EVENT_CLASS */
+
 static void
 history_str_free(char *buf)
 {
diff --git a/module/zfs/zfs_vfsops.c b/module/zfs/zfs_vfsops.c
index eea78417a..d67f11eca 100644
--- a/module/zfs/zfs_vfsops.c
+++ b/module/zfs/zfs_vfsops.c
@@ -1436,7 +1436,7 @@ zfs_vget(struct super_block *sb, struct inode **ipp, fid_t *fidp)
 
 	gen_mask = -1ULL >> (64 - 8 * i);
 
-	dprintf("getting %llu [%u mask %llx]\n", object, fid_gen, gen_mask);
+	dprintf("getting %llu [%llu mask %llx]\n", object, fid_gen, gen_mask);
 	if ((err = zfs_zget(zsb, object, &zp))) {
 		ZFS_EXIT(zsb);
 		return (err);
@@ -1447,7 +1447,8 @@ zfs_vget(struct super_block *sb, struct inode **ipp, fid_t *fidp)
 	if (zp_gen == 0)
 		zp_gen = 1;
 	if (zp->z_unlinked || zp_gen != fid_gen) {
-		dprintf("znode gen (%u) != fid gen (%u)\n", zp_gen, fid_gen);
+		dprintf("znode gen (%llu) != fid gen (%llu)\n", zp_gen,
+		    fid_gen);
 		iput(ZTOI(zp));
 		ZFS_EXIT(zsb);
 		return (SET_ERROR(EINVAL));