module/zfs/zfs_debug.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
  23  * Copyright (c) 2013 by Delphix. All rights reserved.
  24  */
  25
  26 #include <sys/zfs_context.h>
  27
  28 #if !defined(_KERNEL) || !defined(__linux__)
  29 list_t zfs_dbgmsgs;
  30 int zfs_dbgmsg_size;
  31 kmutex_t zfs_dbgmsgs_lock;
  32 int zfs_dbgmsg_maxsize = 1<<20; /* 1MB */
  33 #endif
  34
  35 /*
  36  * Enable various debugging features.
  37  */
  38 int zfs_flags = 0;
  39
  40 /*
  41  * zfs_recover can be set to nonzero to attempt to recover from
  42  * otherwise-fatal errors, typically caused by on-disk corruption.  When
  43  * set, calls to zfs_panic_recover() will turn into warning messages.
  44  */
  45 int zfs_recover = 0;
  46
  47
  48 void
  49 zfs_panic_recover(const char *fmt, ...)
  50 {
  51         va_list adx;
  52
  53         va_start(adx, fmt);
  54         vcmn_err(zfs_recover ? CE_WARN : CE_PANIC, fmt, adx);
  55         va_end(adx);
  56 }
  57
  58 /*
  59  * Debug logging is enabled by default for production kernel builds.
  60  * The overhead for this is negligible and the logs can be valuable when
  61  * debugging.  For non-production user space builds all debugging except
  62  * logging is enabled since performance is no longer a concern.
  63  */
  64 void
  65 zfs_dbgmsg_init(void)
  66 {
  67 #if !defined(_KERNEL) || !defined(__linux__)
  68         list_create(&zfs_dbgmsgs, sizeof (zfs_dbgmsg_t),
  69             offsetof(zfs_dbgmsg_t, zdm_node));
  70         mutex_init(&zfs_dbgmsgs_lock, NULL, MUTEX_DEFAULT, NULL);
  71 #endif
  72
  73         if (zfs_flags == 0) {
  74 #if defined(_KERNEL)
  75                 zfs_flags = ZFS_DEBUG_DPRINTF;
  76                 spl_debug_set_mask(spl_debug_get_mask() | SD_DPRINTF);
  77                 spl_debug_set_subsys(spl_debug_get_subsys() | SS_USER1);
  78 #else
  79                 zfs_flags = ~ZFS_DEBUG_DPRINTF;
  80 #endif /* _KERNEL */
  81         }
  82 }
  83
  84 void
  85 zfs_dbgmsg_fini(void)
  86 {
  87 #if !defined(_KERNEL) || !defined(__linux__)
  88         zfs_dbgmsg_t *zdm;
  89
  90         while ((zdm = list_remove_head(&zfs_dbgmsgs)) != NULL) {
  91                 int size = sizeof (zfs_dbgmsg_t) + strlen(zdm->zdm_msg);
  92                 kmem_free(zdm, size);
  93                 zfs_dbgmsg_size -= size;
  94         }
  95         mutex_destroy(&zfs_dbgmsgs_lock);
  96         ASSERT0(zfs_dbgmsg_size);
  97 #endif
  98         return;
  99 }
 100
 101 #if !defined(_KERNEL) || !defined(__linux__)
 102 /*
 103  * Print these messages by running:
 104  * echo ::zfs_dbgmsg | mdb -k
 105  *
 106  * Monitor these messages by running:
 107  *      dtrace -q -n 'zfs-dbgmsg{printf("%s\n", stringof(arg0))}'
 108  */
 109 void
 110 zfs_dbgmsg(const char *fmt, ...)
 111 {
 112         int size;
 113         va_list adx;
 114         zfs_dbgmsg_t *zdm;
 115
 116         va_start(adx, fmt);
 117         size = vsnprintf(NULL, 0, fmt, adx);
 118         va_end(adx);
 119
 120         /*
 121          * There is one byte of string in sizeof (zfs_dbgmsg_t), used
 122          * for the terminating null.
 123          */
 124         zdm = kmem_alloc(sizeof (zfs_dbgmsg_t) + size, KM_SLEEP);
 125         zdm->zdm_timestamp = gethrestime_sec();
 126
 127         va_start(adx, fmt);
 128         (void) vsnprintf(zdm->zdm_msg, size + 1, fmt, adx);
 129         va_end(adx);
 130
 131         DTRACE_PROBE1(zfs__dbgmsg, char *, zdm->zdm_msg);
 132
 133         mutex_enter(&zfs_dbgmsgs_lock);
 134         list_insert_tail(&zfs_dbgmsgs, zdm);
 135         zfs_dbgmsg_size += sizeof (zfs_dbgmsg_t) + size;
 136         while (zfs_dbgmsg_size > zfs_dbgmsg_maxsize) {
 137                 zdm = list_remove_head(&zfs_dbgmsgs);
 138                 size = sizeof (zfs_dbgmsg_t) + strlen(zdm->zdm_msg);
 139                 kmem_free(zdm, size);
 140                 zfs_dbgmsg_size -= size;
 141         }
 142         mutex_exit(&zfs_dbgmsgs_lock);
 143 }
 144
 145 void
 146 zfs_dbgmsg_print(const char *tag)
 147 {
 148         zfs_dbgmsg_t *zdm;
 149
 150         (void) printf("ZFS_DBGMSG(%s):\n", tag);
 151         mutex_enter(&zfs_dbgmsgs_lock);
 152         for (zdm = list_head(&zfs_dbgmsgs); zdm;
 153             zdm = list_next(&zfs_dbgmsgs, zdm))
 154                 (void) printf("%s\n", zdm->zdm_msg);
 155         mutex_exit(&zfs_dbgmsgs_lock);
 156 }
 157 #endif
 158
 159 #if defined(_KERNEL)
 160 module_param(zfs_flags, int, 0644);
 161 MODULE_PARM_DESC(zfs_flags, "Set additional debugging flags");
 162
 163 module_param(zfs_recover, int, 0644);
 164 MODULE_PARM_DESC(zfs_recover, "Set to attempt to recover from fatal errors");
 165 #endif /* _KERNEL */