svn commit: r252763 - in stable/8/sys/cddl/contrib/opensolaris/uts/common: fs/zfs fs/zfs/sys sys/fm/fs
Xin LI
delphij at FreeBSD.org
Fri Jul 5 04:02:16 UTC 2013
Author: delphij
Date: Fri Jul 5 04:02:15 2013
New Revision: 252763
URL: http://svnweb.freebsd.org/changeset/base/252763
Log:
MFC r251636: illumos #3749 zfs event processing should work on R/O root
filesystems
This log is a modified version of the original one written by gibbs@,
to account for changes made during the illumos RTI process.
Allow ZFS asynchronous event handling to proceed even if the root file
system is mounted read-only. This restriction appears to have been put
in place to avoid errors with updating the configuration cache file.
However:
o The majority of asynchronous event handling does not involve
configuration cache file updates.
o The configuration cache file need not be on the root file system,
so the check was not complete.
o Other classes of errors (e.g. file system full) can also prevent
a successful update yet do not prevent asynchronous event processing.
o Configurations such as NanoBSD never have a read-write root,
so ZFS event processing is permanently disabled in these systems.
o Failure to handle asynchronous events promptly can extend the
window of time that a pool is in a critical state.
At worst, a missed configuration cache update will force the operator to
perform a manual "zfs import" (note -f is not required) to inform the
system about a newly created pool. To minimize the likelihood of this
rare occurrence, configuration cache write failures now emit FMA events
(via devctl) so the operator can take corrective action, and the write
is retried every 5 minutes. The retry interval, in seconds, is tunable
via the sysctl "vfs.zfs.ccw_retry_interval".
As a side effect of reporting configuration cache events, other sysevents,
such as re-silver start/stop, are now also reported via devctl.
sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c:
o As is done in zfs_fm.c, provide a manual declaration for
devctl_notify(). Both declarations could be combined
into spa_impl.h, but the declaration is fault management
related, not spa specific. sys/fm/fs/zfs.h would be ideal
if it weren't so public and reserved for FMA string
definitions. I'm open to suggestions on how to improve
this nit while minimizing our divergence from Solaris.
o Use devctl_notify() to implement sysevent support in
spa_event_notify(). The subsystem is EC_ZFS so that
these events can never collide with those emitted in
zfs_fm.c.
o Add the sysctl "vfs.zfs.ccw_retry_interval". The value
defaults to 5 minutes and is used to rate limit, on a
per-pool basis, configuration cache file write attempts.
o Modify spa_async_dispatch to honor configuration cache
write limiting. If other events are pending, a configuration
cache write will be attempted at the same time, so the
rate limiting only applies when the asynchronous dispatch
system is otherwise idle. Async events should be rare
(e.g. device arrival/departure) and configuration cache
writes rarer, so a more complicated system to strictly
honor the retry limit seems unwarranted.
o Remove check in spa_async_dispatch() for the root file
system being read-write.
sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_config.c:
Instead of silently ignoring configuration cache write
failures, report them via a new FMA event as well as
to the console. The current zfs_ereport_post() doesn't
allow arbitrary name=value pairs to be appended to the
report, so the configuration cache file name is only
available on the console output. This limitation should
be addressed in a future update.
Note: This error report is only posted once per incident,
to avoid spamming.
sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa_impl.h:
Add a hrtime_t to the spa data structure to track the
time (via gethrtime()) of the last configuration cache file
write failure. This is referenced in spa_async_dispatch()
to effect the rate limiting.
sys/cddl/contrib/opensolaris/uts/common/sys/fm/fs/zfs.h:
Add FM_EREPORT_ZFS_CONFIG_CACHE_WRITE as an ereport class.
Submitted by: gibbs
Reviewed by: Matthew Ahrens <mahrens at delphix.com>,
Eric Schrock <eric.schrock at delphix.com>,
Christopher Siden <christopher.siden at delphix.com>
Sponsored by: Spectra Logic
Modified:
stable/8/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c
stable/8/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_config.c
stable/8/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa_impl.h
stable/8/sys/cddl/contrib/opensolaris/uts/common/sys/fm/fs/zfs.h
Directory Properties:
stable/8/sys/ (props changed)
stable/8/sys/cddl/ (props changed)
stable/8/sys/cddl/contrib/opensolaris/ (props changed)
Modified: stable/8/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c
==============================================================================
--- stable/8/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c Fri Jul 5 04:01:25 2013 (r252762)
+++ stable/8/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c Fri Jul 5 04:02:15 2013 (r252763)
@@ -88,6 +88,12 @@ TUNABLE_INT("vfs.zfs.check_hostid", &che
SYSCTL_INT(_vfs_zfs, OID_AUTO, check_hostid, CTLFLAG_RW, &check_hostid, 0,
"Check hostid on import?");
+/*
+ * The interval, in seconds, at which failed configuration cache file writes
+ * should be retried.
+ */
+static int zfs_ccw_retry_interval = 300;
+
typedef enum zti_modes {
zti_mode_fixed, /* value is # of threads (min 1) */
zti_mode_online_percent, /* value is % of online CPUs */
@@ -5852,13 +5858,34 @@ spa_async_resume(spa_t *spa)
mutex_exit(&spa->spa_async_lock);
}
+static boolean_t
+spa_async_tasks_pending(spa_t *spa)
+{
+ uint_t non_config_tasks;
+ uint_t config_task;
+ boolean_t config_task_suspended;
+
+ non_config_tasks = spa->spa_async_tasks & ~SPA_ASYNC_CONFIG_UPDATE;
+ config_task = spa->spa_async_tasks & SPA_ASYNC_CONFIG_UPDATE;
+ if (spa->spa_ccw_fail_time == 0) {
+ config_task_suspended = B_FALSE;
+ } else {
+ config_task_suspended =
+ (gethrtime() - spa->spa_ccw_fail_time) <
+ (zfs_ccw_retry_interval * NANOSEC);
+ }
+
+ return (non_config_tasks || (config_task && !config_task_suspended));
+}
+
static void
spa_async_dispatch(spa_t *spa)
{
mutex_enter(&spa->spa_async_lock);
- if (spa->spa_async_tasks && !spa->spa_async_suspended &&
+ if (spa_async_tasks_pending(spa) &&
+ !spa->spa_async_suspended &&
spa->spa_async_thread == NULL &&
- rootdir != NULL && !vn_is_readonly(rootdir))
+ rootdir != NULL)
spa->spa_async_thread = thread_create(NULL, 0,
spa_async_thread, spa, 0, &p0, TS_RUN, maxclsyspri);
mutex_exit(&spa->spa_async_lock);
Modified: stable/8/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_config.c
==============================================================================
--- stable/8/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_config.c Fri Jul 5 04:01:25 2013 (r252762)
+++ stable/8/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_config.c Fri Jul 5 04:02:15 2013 (r252763)
@@ -27,6 +27,7 @@
#include <sys/zfs_context.h>
#include <sys/spa.h>
+#include <sys/fm/fs/zfs.h>
#include <sys/spa_impl.h>
#include <sys/nvpair.h>
#include <sys/uio.h>
@@ -139,7 +140,7 @@ out:
kobj_close_file(file);
}
-static void
+static int
spa_config_write(spa_config_dirent_t *dp, nvlist_t *nvl)
{
size_t buflen;
@@ -147,13 +148,14 @@ spa_config_write(spa_config_dirent_t *dp
vnode_t *vp;
int oflags = FWRITE | FTRUNC | FCREAT | FOFFMAX;
char *temp;
+ int err;
/*
* If the nvlist is empty (NULL), then remove the old cachefile.
*/
if (nvl == NULL) {
- (void) vn_remove(dp->scd_path, UIO_SYSSPACE, RMFILE);
- return;
+ err = vn_remove(dp->scd_path, UIO_SYSSPACE, RMFILE);
+ return (err);
}
/*
@@ -174,12 +176,14 @@ spa_config_write(spa_config_dirent_t *dp
*/
(void) snprintf(temp, MAXPATHLEN, "%s.tmp", dp->scd_path);
- if (vn_open(temp, UIO_SYSSPACE, oflags, 0644, &vp, CRCREAT, 0) == 0) {
- if (vn_rdwr(UIO_WRITE, vp, buf, buflen, 0, UIO_SYSSPACE,
- 0, RLIM64_INFINITY, kcred, NULL) == 0 &&
- VOP_FSYNC(vp, FSYNC, kcred, NULL) == 0) {
- (void) vn_rename(temp, dp->scd_path, UIO_SYSSPACE);
- }
+ err = vn_open(temp, UIO_SYSSPACE, oflags, 0644, &vp, CRCREAT, 0);
+ if (err == 0) {
+ err = vn_rdwr(UIO_WRITE, vp, buf, buflen, 0, UIO_SYSSPACE,
+ 0, RLIM64_INFINITY, kcred, NULL);
+ if (err == 0)
+ err = VOP_FSYNC(vp, FSYNC, kcred, NULL);
+ if (err == 0)
+ err = vn_rename(temp, dp->scd_path, UIO_SYSSPACE);
(void) VOP_CLOSE(vp, oflags, 1, 0, kcred, NULL);
}
@@ -187,6 +191,7 @@ spa_config_write(spa_config_dirent_t *dp
kmem_free(buf, buflen);
kmem_free(temp, MAXPATHLEN);
+ return (err);
}
/*
@@ -198,6 +203,8 @@ spa_config_sync(spa_t *target, boolean_t
{
spa_config_dirent_t *dp, *tdp;
nvlist_t *nvl;
+ boolean_t ccw_failure;
+ int error;
ASSERT(MUTEX_HELD(&spa_namespace_lock));
@@ -209,6 +216,7 @@ spa_config_sync(spa_t *target, boolean_t
* cachefile is changed, the new one is pushed onto this list, allowing
* us to update previous cachefiles that no longer contain this pool.
*/
+ ccw_failure = B_FALSE;
for (dp = list_head(&target->spa_config_list); dp != NULL;
dp = list_next(&target->spa_config_list, dp)) {
spa_t *spa = NULL;
@@ -241,10 +249,32 @@ spa_config_sync(spa_t *target, boolean_t
mutex_exit(&spa->spa_props_lock);
}
- spa_config_write(dp, nvl);
+ error = spa_config_write(dp, nvl);
+ if (error != 0)
+ ccw_failure = B_TRUE;
nvlist_free(nvl);
}
+ if (ccw_failure) {
+ /*
+ * Keep trying so that configuration data is
+ * written if/when any temporary filesystem
+ * resource issues are resolved.
+ */
+ if (target->spa_ccw_fail_time == 0) {
+ zfs_ereport_post(FM_EREPORT_ZFS_CONFIG_CACHE_WRITE,
+ target, NULL, NULL, 0, 0);
+ }
+ target->spa_ccw_fail_time = gethrtime();
+ spa_async_request(target, SPA_ASYNC_CONFIG_UPDATE);
+ } else {
+ /*
+ * Do not rate limit future attempts to update
+ * the config cache.
+ */
+ target->spa_ccw_fail_time = 0;
+ }
+
/*
* Remove any config entries older than the current one.
*/
Modified: stable/8/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa_impl.h
==============================================================================
--- stable/8/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa_impl.h Fri Jul 5 04:01:25 2013 (r252762)
+++ stable/8/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa_impl.h Fri Jul 5 04:02:15 2013 (r252763)
@@ -241,6 +241,7 @@ struct spa {
uint64_t spa_deadman_calls; /* number of deadman calls */
uint64_t spa_sync_starttime; /* starting time fo spa_sync */
uint64_t spa_deadman_synctime; /* deadman expiration timer */
+ hrtime_t spa_ccw_fail_time; /* Conf cache write fail time */
/*
* spa_refcount & spa_config_lock must be the last elements
* because refcount_t changes size based on compilation options.
Modified: stable/8/sys/cddl/contrib/opensolaris/uts/common/sys/fm/fs/zfs.h
==============================================================================
--- stable/8/sys/cddl/contrib/opensolaris/uts/common/sys/fm/fs/zfs.h Fri Jul 5 04:01:25 2013 (r252762)
+++ stable/8/sys/cddl/contrib/opensolaris/uts/common/sys/fm/fs/zfs.h Fri Jul 5 04:02:15 2013 (r252763)
@@ -46,6 +46,7 @@ extern "C" {
#define FM_EREPORT_ZFS_IO_FAILURE "io_failure"
#define FM_EREPORT_ZFS_PROBE_FAILURE "probe_failure"
#define FM_EREPORT_ZFS_LOG_REPLAY "log_replay"
+#define FM_EREPORT_ZFS_CONFIG_CACHE_WRITE "config_cache_write"
#define FM_EREPORT_PAYLOAD_ZFS_POOL "pool"
#define FM_EREPORT_PAYLOAD_ZFS_POOL_FAILMODE "pool_failmode"
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