Date: Wed, 20 Jul 2011 22:48:48 +0000 (UTC) From: "Justin T. Gibbs" <gibbs@FreeBSD.org> To: src-committers@freebsd.org, svn-src-projects@freebsd.org Subject: svn commit: r224237 - in projects/zfsd/head/sys/cddl/contrib/opensolaris/uts/common: fs/zfs fs/zfs/sys sys/fm/fs Message-ID: <201107202248.p6KMmmpI035254@svn.freebsd.org>
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Author: gibbs Date: Wed Jul 20 22:48:48 2011 New Revision: 224237 URL: http://svn.freebsd.org/changeset/base/224237 Log: 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 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". sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.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. sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa_impl.h: Add a uint64_t to the spa data structure to track the time (via LBOLT) 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. Sponsored by: Spectra Logic Corporation Modified: projects/zfsd/head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c projects/zfsd/head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_config.c projects/zfsd/head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa_impl.h projects/zfsd/head/sys/cddl/contrib/opensolaris/uts/common/sys/fm/fs/zfs.h Modified: projects/zfsd/head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c ============================================================================== --- projects/zfsd/head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c Wed Jul 20 21:18:05 2011 (r224236) +++ projects/zfsd/head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c Wed Jul 20 22:48:48 2011 (r224237) @@ -73,10 +73,20 @@ /* Check hostid on import? */ static int check_hostid = 1; +/* + * The interval at which failed configuration cache file writes + * should be retried. + */ +static int zfs_ccw_retry_interval = 300; + SYSCTL_DECL(_vfs_zfs); TUNABLE_INT("vfs.zfs.check_hostid", &check_hostid); SYSCTL_INT(_vfs_zfs, OID_AUTO, check_hostid, CTLFLAG_RW, &check_hostid, 0, "Check hostid on import?"); +TUNABLE_INT("vfs.zfs.ccw_retry_interval", &zfs_ccw_retry_interval); +SYSCTL_INT(_vfs_zfs, OID_AUTO, ccw_retry_interval, CTLFLAG_RW, + &zfs_ccw_retry_interval, 0, + "Configuration cache file write, retry after failure, interval (seconds)"); typedef enum zti_modes { zti_mode_fixed, /* value is # of threads (min 1) */ @@ -5178,13 +5188,34 @@ spa_async_resume(spa_t *spa) mutex_exit(&spa->spa_async_lock); } +static int +spa_async_tasks_pending(spa_t *spa) +{ + u_int non_config_tasks; + u_int 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 = + (ddi_get_lbolt64() - spa->spa_ccw_fail_time) + < (zfs_ccw_retry_interval * hz); + } + + 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: projects/zfsd/head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_config.c ============================================================================== --- projects/zfsd/head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_config.c Wed Jul 20 21:18:05 2011 (r224236) +++ projects/zfsd/head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_config.c Wed Jul 20 22:48:48 2011 (r224237) @@ -24,6 +24,7 @@ */ #include <sys/zfs_context.h> +#include <sys/fm/fs/zfs.h> #include <sys/spa.h> #include <sys/spa_impl.h> #include <sys/nvpair.h> @@ -136,7 +137,7 @@ out: kobj_close_file(file); } -static void +static int spa_config_write(spa_config_dirent_t *dp, nvlist_t *nvl) { size_t buflen; @@ -144,13 +145,14 @@ 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); } /* @@ -171,11 +173,12 @@ 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) { + if ((err = vn_rdwr(UIO_WRITE, vp, buf, buflen, 0, UIO_SYSSPACE, + 0, RLIM64_INFINITY, kcred, NULL)) == 0 && + (err = VOP_FSYNC(vp, FSYNC, kcred, NULL)) == 0) { + err = vn_rename(temp, dp->scd_path, UIO_SYSSPACE); } (void) VOP_CLOSE(vp, oflags, 1, 0, kcred, NULL); } @@ -184,6 +187,7 @@ spa_config_write(spa_config_dirent_t *dp kmem_free(buf, buflen); kmem_free(temp, MAXPATHLEN); + return (err); } /* @@ -195,6 +199,8 @@ 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)); @@ -206,6 +212,7 @@ 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; @@ -238,10 +245,35 @@ 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) { + + printf("ZFS ERROR: Update of cache file %s failed: " + "Errno %d\n", dp->scd_path, error); + 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. + */ + target->spa_ccw_fail_time = ddi_get_lbolt64(); + spa_async_request(target, SPA_ASYNC_CONFIG_UPDATE); + zfs_ereport_post(FM_EREPORT_ZFS_CONFIG_CACHE_WRITE, + target, NULL, NULL, 0, 0); + } 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: projects/zfsd/head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa_impl.h ============================================================================== --- projects/zfsd/head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa_impl.h Wed Jul 20 21:18:05 2011 (r224236) +++ projects/zfsd/head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/spa_impl.h Wed Jul 20 22:48:48 2011 (r224237) @@ -216,6 +216,7 @@ struct spa { int spa_vdev_locks; /* locks grabbed */ uint64_t spa_creation_version; /* version at pool creation */ uint64_t spa_prev_software_version; + int64_t spa_ccw_fail_time; /* Conf cache write fail time */ /* * spa_refcnt & spa_config_lock must be the last elements * because refcount_t changes size based on compilation options. Modified: projects/zfsd/head/sys/cddl/contrib/opensolaris/uts/common/sys/fm/fs/zfs.h ============================================================================== --- projects/zfsd/head/sys/cddl/contrib/opensolaris/uts/common/sys/fm/fs/zfs.h Wed Jul 20 21:18:05 2011 (r224236) +++ projects/zfsd/head/sys/cddl/contrib/opensolaris/uts/common/sys/fm/fs/zfs.h Wed Jul 20 22:48:48 2011 (r224237) @@ -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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