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/*
* 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.
* Copyright (c) 2013 by Delphix. All rights reserved.
*/
#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) {
int size = sizeof (zfs_dbgmsg_t) + strlen(zdm->zdm_msg);
kmem_free(zdm, size);
zfs_dbgmsg_size -= size;
}
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
*
* 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);
}
void
zfs_dbgmsg_print(const char *tag)
{
zfs_dbgmsg_t *zdm;
(void) printf("ZFS_DBGMSG(%s):\n", tag);
mutex_enter(&zfs_dbgmsgs_lock);
for (zdm = list_head(&zfs_dbgmsgs); zdm;
zdm = list_next(&zfs_dbgmsgs, zdm))
(void) printf("%s\n", zdm->zdm_msg);
mutex_exit(&zfs_dbgmsgs_lock);
}
#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 */
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