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Illumos 3749 - zfs event processing should work on R/O root filesystems

3749 zfs event processing should work on R/O root filesystems
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Eric Schrock <eric.schrock@delphix.com>
Approved by: Christopher Siden <christopher.siden@delphix.com>

References:
  https://www.illumos.org/issues/3749
  illumos/illumos-gate@3cb69f7

Porting notes:
- [include/sys/spa_impl.h]
  - ffe9d38 Add generic errata infrastructure
  - 1421c89 Add visibility in to arc_read
- [include/sys/fm/fs/zfs.h]
  - 2668527 Add linux events
  - 6283f55 Support custom build directories and move includes
- [module/zfs/spa_config.c]
  - Updated spa_config_sync() to match illumos with the exception
    of a Linux specific block.

Ported-by: kernelOfTruth kerneloftruth@gmail.com
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
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Will Andrews authored and behlendorf committed Dec 31, 2015
1 parent 7ea4f88 commit e6cfd633be909956c8a6998f478ceb32558c210c
Showing with 77 additions and 20 deletions.
  1. +1 −0 include/sys/fm/fs/zfs.h
  2. +1 −0 include/sys/spa_impl.h
  3. +29 −2 module/zfs/spa.c
  4. +46 −18 module/zfs/spa_config.c
@@ -56,6 +56,7 @@ 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_ZFS_RESILVER_START "resilver.start"
#define FM_EREPORT_ZFS_RESILVER_FINISH "resilver.finish"
#define FM_EREPORT_ZFS_SCRUB_START "scrub.start"
@@ -252,6 +252,7 @@ struct spa {
uint64_t spa_deadman_synctime; /* deadman expiration timer */
uint64_t spa_errata; /* errata issues detected */
spa_stats_t spa_stats; /* assorted spa statistics */
hrtime_t spa_ccw_fail_time; /* Conf cache write fail time */

/*
* spa_refcount & spa_config_lock must be the last elements
@@ -82,6 +82,12 @@
#include "zfs_prop.h"
#include "zfs_comutil.h"

/*
* 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_BATCH, /* cpu-intensive; value is ignored */
@@ -5912,13 +5918,34 @@ 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);
@@ -26,6 +26,7 @@
*/

#include <sys/spa.h>
#include <sys/fm/fs/zfs.h>
#include <sys/spa_impl.h>
#include <sys/nvpair.h>
#include <sys/uio.h>
@@ -145,22 +146,22 @@ spa_config_load(void)
kobj_close_file(file);
}

static void
static int
spa_config_write(spa_config_dirent_t *dp, nvlist_t *nvl)
{
size_t buflen;
char *buf;
vnode_t *vp;
int oflags = FWRITE | FTRUNC | FCREAT | FOFFMAX;
int error;
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);
}

/*
@@ -181,16 +182,16 @@ spa_config_write(spa_config_dirent_t *dp, nvlist_t *nvl)
* and overwritten in place. In the event of an error the file is
* unlinked to make sure we always have a consistent view of the data.
*/
error = vn_open(dp->scd_path, UIO_SYSSPACE, oflags, 0644, &vp, 0, 0);
if (error == 0) {
error = vn_rdwr(UIO_WRITE, vp, buf, buflen, 0,
err = vn_open(dp->scd_path, UIO_SYSSPACE, oflags, 0644, &vp, 0, 0);
if (err == 0) {
err = vn_rdwr(UIO_WRITE, vp, buf, buflen, 0,
UIO_SYSSPACE, 0, RLIM64_INFINITY, kcred, NULL);
if (error == 0)
error = VOP_FSYNC(vp, FSYNC, kcred, NULL);
if (err == 0)
err = VOP_FSYNC(vp, FSYNC, kcred, NULL);

(void) VOP_CLOSE(vp, oflags, 1, 0, kcred, NULL);

if (error)
if (err)
(void) vn_remove(dp->scd_path, UIO_SYSSPACE, RMFILE);
}
#else
@@ -201,13 +202,14 @@ spa_config_write(spa_config_dirent_t *dp, nvlist_t *nvl)
*/
(void) snprintf(temp, MAXPATHLEN, "%s.tmp", dp->scd_path);

error = vn_open(temp, UIO_SYSSPACE, oflags, 0644, &vp, CRCREAT, 0);
if (error == 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);
}

@@ -216,6 +218,7 @@ spa_config_write(spa_config_dirent_t *dp, nvlist_t *nvl)

vmem_free(buf, buflen);
kmem_free(temp, MAXPATHLEN);
return (err);
}

/*
@@ -233,6 +236,8 @@ spa_config_sync(spa_t *target, boolean_t removing, boolean_t postsysevent)
spa_config_dirent_t *dp, *tdp;
nvlist_t *nvl;
char *pool_name;
boolean_t ccw_failure;
int error = 0;

ASSERT(MUTEX_HELD(&spa_namespace_lock));

@@ -244,6 +249,7 @@ spa_config_sync(spa_t *target, boolean_t removing, boolean_t postsysevent)
* 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;
@@ -290,10 +296,32 @@ spa_config_sync(spa_t *target, boolean_t removing, boolean_t postsysevent)
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.
*/

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