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-rw-r--r--uts/common/fs/zfs/zfs_debug.c95
1 files changed, 95 insertions, 0 deletions
diff --git a/uts/common/fs/zfs/zfs_debug.c b/uts/common/fs/zfs/zfs_debug.c
new file mode 100644
index 000000000000..d0f411a99350
--- /dev/null
+++ b/uts/common/fs/zfs/zfs_debug.c
@@ -0,0 +1,95 @@
+/*
+ * 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.
+ */
+
+#include <sys/zfs_context.h>
+
+list_t zfs_dbgmsgs;
+int zfs_dbgmsg_size;
+kmutex_t zfs_dbgmsgs_lock;
+int zfs_dbgmsg_maxsize = 1<<20; /* 1MB */
+
+void
+zfs_dbgmsg_init(void)
+{
+ list_create(&zfs_dbgmsgs, sizeof (zfs_dbgmsg_t),
+ offsetof(zfs_dbgmsg_t, zdm_node));
+ mutex_init(&zfs_dbgmsgs_lock, NULL, MUTEX_DEFAULT, NULL);
+}
+
+void
+zfs_dbgmsg_fini(void)
+{
+ zfs_dbgmsg_t *zdm;
+
+ while ((zdm = list_remove_head(&zfs_dbgmsgs)) != NULL) {
+ int size = sizeof (zfs_dbgmsg_t) + strlen(zdm->zdm_msg);
+ kmem_free(zdm, size);
+ zfs_dbgmsg_size -= size;
+ }
+ mutex_destroy(&zfs_dbgmsgs_lock);
+ ASSERT3U(zfs_dbgmsg_size, ==, 0);
+}
+
+/*
+ * Print these messages by running:
+ * echo ::zfs_dbgmsg | mdb -k
+ *
+ * Monitor these messages by running:
+ * dtrace -q -n 'zfs-dbgmsg{printf("%s\n", stringof(arg0))}'
+ */
+void
+zfs_dbgmsg(const char *fmt, ...)
+{
+ int size;
+ va_list adx;
+ zfs_dbgmsg_t *zdm;
+
+ va_start(adx, fmt);
+ size = vsnprintf(NULL, 0, fmt, adx);
+ va_end(adx);
+
+ /*
+ * 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->zdm_timestamp = gethrestime_sec();
+
+ va_start(adx, fmt);
+ (void) vsnprintf(zdm->zdm_msg, size + 1, fmt, adx);
+ va_end(adx);
+
+ DTRACE_PROBE1(zfs__dbgmsg, char *, zdm->zdm_msg);
+
+ mutex_enter(&zfs_dbgmsgs_lock);
+ list_insert_tail(&zfs_dbgmsgs, zdm);
+ zfs_dbgmsg_size += sizeof (zfs_dbgmsg_t) + size;
+ while (zfs_dbgmsg_size > zfs_dbgmsg_maxsize) {
+ zdm = list_remove_head(&zfs_dbgmsgs);
+ size = sizeof (zfs_dbgmsg_t) + strlen(zdm->zdm_msg);
+ kmem_free(zdm, size);
+ zfs_dbgmsg_size -= size;
+ }
+ mutex_exit(&zfs_dbgmsgs_lock);
+}