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  * This should only be used as a last resort, as it typically results
  45  * in leaked space, or worse.
  46  */
  47 int zfs_recover = 0;
  48
  49
  50 void
  51 zfs_panic_recover(const char *fmt, ...)
  52 {
  53         va_list adx;
  54
  55         va_start(adx, fmt);
  56         vcmn_err(zfs_recover ? CE_WARN : CE_PANIC, fmt, adx);
  57         va_end(adx);
  58 }
  59
  60 /*
  61  * Debug logging is enabled by default for production kernel builds.
  62  * The overhead for this is negligible and the logs can be valuable when
  63  * debugging.  For non-production user space builds all debugging except
  64  * logging is enabled since performance is no longer a concern.
  65  */
  66 void
  67 zfs_dbgmsg_init(void)
  68 {
  69 #if !defined(_KERNEL) || !defined(__linux__)
  70         list_create(&zfs_dbgmsgs, sizeof (zfs_dbgmsg_t),
  71             offsetof(zfs_dbgmsg_t, zdm_node));
  72         mutex_init(&zfs_dbgmsgs_lock, NULL, MUTEX_DEFAULT, NULL);
  73 #endif
  74
  75         if (zfs_flags == 0) {
  76 #if defined(_KERNEL)
  77                 zfs_flags = ZFS_DEBUG_DPRINTF;
  78                 spl_debug_set_mask(spl_debug_get_mask() | SD_DPRINTF);
  79                 spl_debug_set_subsys(spl_debug_get_subsys() | SS_USER1);
  80 #else
  81                 zfs_flags = ~ZFS_DEBUG_DPRINTF;
  82 #endif /* _KERNEL */
  83         }
  84 }
  85
  86 void
  87 zfs_dbgmsg_fini(void)
  88 {
  89 #if !defined(_KERNEL) || !defined(__linux__)
  90         zfs_dbgmsg_t *zdm;
  91
  92         while ((zdm = list_remove_head(&zfs_dbgmsgs)) != NULL) {
  93                 int size = sizeof (zfs_dbgmsg_t) + strlen(zdm->zdm_msg);
  94                 kmem_free(zdm, size);
  95                 zfs_dbgmsg_size -= size;
  96         }
  97         mutex_destroy(&zfs_dbgmsgs_lock);
  98         ASSERT0(zfs_dbgmsg_size);
  99 #endif
 100         return;
 101 }
 102
 103 #if !defined(_KERNEL) || !defined(__linux__)
 104 /*
 105  * Print these messages by running:
 106  * echo ::zfs_dbgmsg | mdb -k
 107  *
 108  * Monitor these messages by running:
 109  *      dtrace -q -n 'zfs-dbgmsg{printf("%s\n", stringof(arg0))}'
 110  */
 111 void
 112 zfs_dbgmsg(const char *fmt, ...)
 113 {
 114         int size;
 115         va_list adx;
 116         zfs_dbgmsg_t *zdm;
 117
 118         va_start(adx, fmt);
 119         size = vsnprintf(NULL, 0, fmt, adx);
 120         va_end(adx);
 121
 122         /*
 123          * There is one byte of string in sizeof (zfs_dbgmsg_t), used
 124          * for the terminating null.
 125          */
 126         zdm = kmem_alloc(sizeof (zfs_dbgmsg_t) + size, KM_SLEEP);
 127         zdm->zdm_timestamp = gethrestime_sec();
 128
 129         va_start(adx, fmt);
 130         (void) vsnprintf(zdm->zdm_msg, size + 1, fmt, adx);
 131         va_end(adx);
 132
 133         DTRACE_PROBE1(zfs__dbgmsg, char *, zdm->zdm_msg);
 134
 135         mutex_enter(&zfs_dbgmsgs_lock);
 136         list_insert_tail(&zfs_dbgmsgs, zdm);
 137         zfs_dbgmsg_size += sizeof (zfs_dbgmsg_t) + size;
 138         while (zfs_dbgmsg_size > zfs_dbgmsg_maxsize) {
 139                 zdm = list_remove_head(&zfs_dbgmsgs);
 140                 size = sizeof (zfs_dbgmsg_t) + strlen(zdm->zdm_msg);
 141                 kmem_free(zdm, size);
 142                 zfs_dbgmsg_size -= size;
 143         }
 144         mutex_exit(&zfs_dbgmsgs_lock);
 145 }
 146
 147 void
 148 zfs_dbgmsg_print(const char *tag)
 149 {
 150         zfs_dbgmsg_t *zdm;
 151
 152         (void) printf("ZFS_DBGMSG(%s):\n", tag);
 153         mutex_enter(&zfs_dbgmsgs_lock);
 154         for (zdm = list_head(&zfs_dbgmsgs); zdm;
 155             zdm = list_next(&zfs_dbgmsgs, zdm))
 156                 (void) printf("%s\n", zdm->zdm_msg);
 157         mutex_exit(&zfs_dbgmsgs_lock);
 158 }
 159 #endif
 160
 161 #if defined(_KERNEL)
 162 module_param(zfs_flags, int, 0644);
 163 MODULE_PARM_DESC(zfs_flags, "Set additional debugging flags");
 164
 165 module_param(zfs_recover, int, 0644);
 166 MODULE_PARM_DESC(zfs_recover, "Set to attempt to recover from fatal errors");
 167 #endif /* _KERNEL */