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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) 2006, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2013 by Delphix. All rights reserved.
*/
/*
* Routines to manage the on-disk persistent error log.
*
* Each pool stores a log of all logical data errors seen during normal
* operation. This is actually the union of two distinct logs: the last log,
* and the current log. All errors seen are logged to the current log. When a
* scrub completes, the current log becomes the last log, the last log is thrown
* out, and the current log is reinitialized. This way, if an error is somehow
* corrected, a new scrub will show that that it no longer exists, and will be
* deleted from the log when the scrub completes.
*
* The log is stored using a ZAP object whose key is a string form of the
* zbookmark tuple (objset, object, level, blkid), and whose contents is an
* optional 'objset:object' human-readable string describing the data. When an
* error is first logged, this string will be empty, indicating that no name is
* known. This prevents us from having to issue a potentially large amount of
* I/O to discover the object name during an error path. Instead, we do the
* calculation when the data is requested, storing the result so future queries
* will be faster.
*
* This log is then shipped into an nvlist where the key is the dataset name and
* the value is the object name. Userland is then responsible for uniquifying
* this list and displaying it to the user.
*/
#include <sys/dmu_tx.h>
#include <sys/spa.h>
#include <sys/spa_impl.h>
#include <sys/zap.h>
#include <sys/zio.h>
/*
* Convert a bookmark to a string.
*/
static void
bookmark_to_name(zbookmark_t *zb, char *buf, size_t len)
{
(void) snprintf(buf, len, "%llx:%llx:%llx:%llx",
(u_longlong_t)zb->zb_objset, (u_longlong_t)zb->zb_object,
(u_longlong_t)zb->zb_level, (u_longlong_t)zb->zb_blkid);
}
/*
* Convert a string to a bookmark
*/
#ifdef _KERNEL
static void
name_to_bookmark(char *buf, zbookmark_t *zb)
{
zb->zb_objset = strtonum(buf, &buf);
ASSERT(*buf == ':');
zb->zb_object = strtonum(buf + 1, &buf);
ASSERT(*buf == ':');
zb->zb_level = (int)strtonum(buf + 1, &buf);
ASSERT(*buf == ':');
zb->zb_blkid = strtonum(buf + 1, &buf);
ASSERT(*buf == '\0');
}
#endif
/*
* Log an uncorrectable error to the persistent error log. We add it to the
* spa's list of pending errors. The changes are actually synced out to disk
* during spa_errlog_sync().
*/
void
spa_log_error(spa_t *spa, zio_t *zio)
{
zbookmark_t *zb = &zio->io_logical->io_bookmark;
spa_error_entry_t search;
spa_error_entry_t *new;
avl_tree_t *tree;
avl_index_t where;
/*
* If we are trying to import a pool, ignore any errors, as we won't be
* writing to the pool any time soon.
*/
if (spa_load_state(spa) == SPA_LOAD_TRYIMPORT)
return;
mutex_enter(&spa->spa_errlist_lock);
/*
* If we have had a request to rotate the log, log it to the next list
* instead of the current one.
*/
if (spa->spa_scrub_active || spa->spa_scrub_finished)
tree = &spa->spa_errlist_scrub;
else
tree = &spa->spa_errlist_last;
search.se_bookmark = *zb;
if (avl_find(tree, &search, &where) != NULL) {
mutex_exit(&spa->spa_errlist_lock);
return;
}
new = kmem_zalloc(sizeof (spa_error_entry_t), KM_SLEEP);
new->se_bookmark = *zb;
avl_insert(tree, new, where);
mutex_exit(&spa->spa_errlist_lock);
}
/*
* Return the number of errors currently in the error log. This is actually the
* sum of both the last log and the current log, since we don't know the union
* of these logs until we reach userland.
*/
uint64_t
spa_get_errlog_size(spa_t *spa)
{
uint64_t total = 0, count;
mutex_enter(&spa->spa_errlog_lock);
if (spa->spa_errlog_scrub != 0 &&
zap_count(spa->spa_meta_objset, spa->spa_errlog_scrub,
&count) == 0)
total += count;
if (spa->spa_errlog_last != 0 && !spa->spa_scrub_finished &&
zap_count(spa->spa_meta_objset, spa->spa_errlog_last,
&count) == 0)
total += count;
mutex_exit(&spa->spa_errlog_lock);
mutex_enter(&spa->spa_errlist_lock);
total += avl_numnodes(&spa->spa_errlist_last);
total += avl_numnodes(&spa->spa_errlist_scrub);
mutex_exit(&spa->spa_errlist_lock);
return (total);
}
#ifdef _KERNEL
static int
process_error_log(spa_t *spa, uint64_t obj, void *addr, size_t *count)
{
zap_cursor_t zc;
zap_attribute_t za;
zbookmark_t zb;
if (obj == 0)
return (0);
for (zap_cursor_init(&zc, spa->spa_meta_objset, obj);
zap_cursor_retrieve(&zc, &za) == 0;
zap_cursor_advance(&zc)) {
if (*count == 0) {
zap_cursor_fini(&zc);
return (SET_ERROR(ENOMEM));
}
name_to_bookmark(za.za_name, &zb);
if (copyout(&zb, (char *)addr +
(*count - 1) * sizeof (zbookmark_t),
sizeof (zbookmark_t)) != 0) {
zap_cursor_fini(&zc);
return (SET_ERROR(EFAULT));
}
*count -= 1;
}
zap_cursor_fini(&zc);
return (0);
}
static int
process_error_list(avl_tree_t *list, void *addr, size_t *count)
{
spa_error_entry_t *se;
for (se = avl_first(list); se != NULL; se = AVL_NEXT(list, se)) {
if (*count == 0)
return (SET_ERROR(ENOMEM));
if (copyout(&se->se_bookmark, (char *)addr +
(*count - 1) * sizeof (zbookmark_t),
sizeof (zbookmark_t)) != 0)
return (SET_ERROR(EFAULT));
*count -= 1;
}
return (0);
}
#endif
/*
* Copy all known errors to userland as an array of bookmarks. This is
* actually a union of the on-disk last log and current log, as well as any
* pending error requests.
*
* Because the act of reading the on-disk log could cause errors to be
* generated, we have two separate locks: one for the error log and one for the
* in-core error lists. We only need the error list lock to log and error, so
* we grab the error log lock while we read the on-disk logs, and only pick up
* the error list lock when we are finished.
*/
int
spa_get_errlog(spa_t *spa, void *uaddr, size_t *count)
{
int ret = 0;
#ifdef _KERNEL
mutex_enter(&spa->spa_errlog_lock);
ret = process_error_log(spa, spa->spa_errlog_scrub, uaddr, count);
if (!ret && !spa->spa_scrub_finished)
ret = process_error_log(spa, spa->spa_errlog_last, uaddr,
count);
mutex_enter(&spa->spa_errlist_lock);
if (!ret)
ret = process_error_list(&spa->spa_errlist_scrub, uaddr,
count);
if (!ret)
ret = process_error_list(&spa->spa_errlist_last, uaddr,
count);
mutex_exit(&spa->spa_errlist_lock);
mutex_exit(&spa->spa_errlog_lock);
#endif
return (ret);
}
/*
* Called when a scrub completes. This simply set a bit which tells which AVL
* tree to add new errors. spa_errlog_sync() is responsible for actually
* syncing the changes to the underlying objects.
*/
void
spa_errlog_rotate(spa_t *spa)
{
mutex_enter(&spa->spa_errlist_lock);
spa->spa_scrub_finished = B_TRUE;
mutex_exit(&spa->spa_errlist_lock);
}
/*
* Discard any pending errors from the spa_t. Called when unloading a faulted
* pool, as the errors encountered during the open cannot be synced to disk.
*/
void
spa_errlog_drain(spa_t *spa)
{
spa_error_entry_t *se;
void *cookie;
mutex_enter(&spa->spa_errlist_lock);
cookie = NULL;
while ((se = avl_destroy_nodes(&spa->spa_errlist_last,
&cookie)) != NULL)
kmem_free(se, sizeof (spa_error_entry_t));
cookie = NULL;
while ((se = avl_destroy_nodes(&spa->spa_errlist_scrub,
&cookie)) != NULL)
kmem_free(se, sizeof (spa_error_entry_t));
mutex_exit(&spa->spa_errlist_lock);
}
/*
* Process a list of errors into the current on-disk log.
*/
static void
sync_error_list(spa_t *spa, avl_tree_t *t, uint64_t *obj, dmu_tx_t *tx)
{
spa_error_entry_t *se;
char buf[64];
void *cookie;
if (avl_numnodes(t) != 0) {
/* create log if necessary */
if (*obj == 0)
*obj = zap_create(spa->spa_meta_objset,
DMU_OT_ERROR_LOG, DMU_OT_NONE,
0, tx);
/* add errors to the current log */
for (se = avl_first(t); se != NULL; se = AVL_NEXT(t, se)) {
char *name = se->se_name ? se->se_name : "";
bookmark_to_name(&se->se_bookmark, buf, sizeof (buf));
(void) zap_update(spa->spa_meta_objset,
*obj, buf, 1, strlen(name) + 1, name, tx);
}
/* purge the error list */
cookie = NULL;
while ((se = avl_destroy_nodes(t, &cookie)) != NULL)
kmem_free(se, sizeof (spa_error_entry_t));
}
}
/*
* Sync the error log out to disk. This is a little tricky because the act of
* writing the error log requires the spa_errlist_lock. So, we need to lock the
* error lists, take a copy of the lists, and then reinitialize them. Then, we
* drop the error list lock and take the error log lock, at which point we
* do the errlog processing. Then, if we encounter an I/O error during this
* process, we can successfully add the error to the list. Note that this will
* result in the perpetual recycling of errors, but it is an unlikely situation
* and not a performance critical operation.
*/
void
spa_errlog_sync(spa_t *spa, uint64_t txg)
{
dmu_tx_t *tx;
avl_tree_t scrub, last;
int scrub_finished;
mutex_enter(&spa->spa_errlist_lock);
/*
* Bail out early under normal circumstances.
*/
if (avl_numnodes(&spa->spa_errlist_scrub) == 0 &&
avl_numnodes(&spa->spa_errlist_last) == 0 &&
!spa->spa_scrub_finished) {
mutex_exit(&spa->spa_errlist_lock);
return;
}
spa_get_errlists(spa, &last, &scrub);
scrub_finished = spa->spa_scrub_finished;
spa->spa_scrub_finished = B_FALSE;
mutex_exit(&spa->spa_errlist_lock);
mutex_enter(&spa->spa_errlog_lock);
tx = dmu_tx_create_assigned(spa->spa_dsl_pool, txg);
/*
* Sync out the current list of errors.
*/
sync_error_list(spa, &last, &spa->spa_errlog_last, tx);
/*
* Rotate the log if necessary.
*/
if (scrub_finished) {
if (spa->spa_errlog_last != 0)
VERIFY(dmu_object_free(spa->spa_meta_objset,
spa->spa_errlog_last, tx) == 0);
spa->spa_errlog_last = spa->spa_errlog_scrub;
spa->spa_errlog_scrub = 0;
sync_error_list(spa, &scrub, &spa->spa_errlog_last, tx);
}
/*
* Sync out any pending scrub errors.
*/
sync_error_list(spa, &scrub, &spa->spa_errlog_scrub, tx);
/*
* Update the MOS to reflect the new values.
*/
(void) zap_update(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
DMU_POOL_ERRLOG_LAST, sizeof (uint64_t), 1,
&spa->spa_errlog_last, tx);
(void) zap_update(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
DMU_POOL_ERRLOG_SCRUB, sizeof (uint64_t), 1,
&spa->spa_errlog_scrub, tx);
dmu_tx_commit(tx);
mutex_exit(&spa->spa_errlog_lock);
}
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