MFV r251626:

ZFS event processing should work on R/O root filesystems

Illumos ZFS issues:
  3749 zfs event processing should work on R/O root filesystems

MFC after:      2 weeks

1 files changed, 40 insertions, 10 deletions

diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_config.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_config.c
index 28fb6f2..0f3bd67 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_config.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_config.c
@@ -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, nvlist_t *nvl)
 	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, nvlist_t *nvl)
 	 */
 	(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, nvlist_t *nvl)
 
 	kmem_free(buf, buflen);
 	kmem_free(temp, MAXPATHLEN);
+	return (err);
 }
 
 /*
@@ -198,6 +203,8 @@ spa_config_sync(spa_t *target, boolean_t removing, boolean_t postsysevent)
 {
 	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 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;
@@ -249,10 +257,32 @@ 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.
 	 */