MFV r268121:

4924 LZ4 Compression for metadata

illumos/illumos-gate@b8289d24d8

MFC after:	2 weeks

cddl/contrib/opensolaris/cmd/zpool/zpool-features.7

@@ -23,7 +23,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd June 30, 2014
+.Dd July 1, 2014
 .Dt ZPOOL-FEATURES 7
 .Os
 .Sh NAME
@@ -235,14 +235,11 @@ administrator can turn on
 compression on any dataset on the
 pool using the
 .Xr zfs 8
-command. Please note that doing so will
+command.
-immediately activate the
+Also, all newly written metadata
-.Sy lz4_compress
+will be compressed with
-feature on the underlying
+.Sy lz4
-pool
+algorithm.
-.Pq even before any data is written ,
-and the feature will not be
-deactivated.
 Since this feature is not read-only compatible, this
 operation will render the pool unimportable on systems without support
 for the
@@ -251,6 +248,12 @@ feature.
 Booting off of
 .Sy lz4
 -compressed root pools is supported.
+.Pp
+This feature becomes
+.Sy active
+as soon as it is enabled and will
+never return to being
+.Sy enabled .
 .It Sy multi_vdev_crash_dump
 .Bl -column "READ\-ONLY COMPATIBLE" "com.joyent:multi_vdev_crash_dump"
 .It GUID Ta com.joyent:multi_vdev_crash_dump

sys/cddl/contrib/opensolaris/common/zfs/zfeature_common.c

@@ -23,6 +23,7 @@
  * Copyright (c) 2013 by Delphix. All rights reserved.
  * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
  * Copyright (c) 2013, Joyent, Inc. All rights reserved.
+ * Copyright (c) 2014, Nexenta Systems, Inc. All rights reserved.
  */
 
 #ifdef _KERNEL
@@ -168,7 +169,7 @@ zpool_feature_init(void)
 	zfeature_register(SPA_FEATURE_LZ4_COMPRESS,
 	    "org.illumos:lz4_compress", "lz4_compress",
 	    "LZ4 compression algorithm support.", B_FALSE, B_FALSE,
-	    B_FALSE, NULL);
+	    B_TRUE, NULL);
 
 	zfeature_register(SPA_FEATURE_MULTI_VDEV_CRASH_DUMP,
 	    "com.joyent:multi_vdev_crash_dump", "multi_vdev_crash_dump",

sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu.c

@@ -24,6 +24,7 @@
  */
 /* Copyright (c) 2013 by Saso Kiselkov. All rights reserved. */
 /* Copyright (c) 2013, Joyent, Inc. All rights reserved. */
+/* Copyright (c) 2014, Nexenta Systems, Inc. All rights reserved. */
 
 #include <sys/dmu.h>
 #include <sys/dmu_impl.h>
@@ -44,6 +45,7 @@
 #include <sys/zio_checksum.h>
 #include <sys/zio_compress.h>
 #include <sys/sa.h>
+#include <sys/zfeature.h>
 #ifdef _KERNEL
 #include <sys/vm.h>
 #include <sys/zfs_znode.h>
@@ -1705,8 +1707,16 @@ dmu_write_policy(objset_t *os, dnode_t *dn, int level, int wp, zio_prop_t *zp)
 		 * XXX -- we should design a compression algorithm
 		 * that specializes in arrays of bps.
 		 */
-		compress = zfs_mdcomp_disable ? ZIO_COMPRESS_EMPTY :
+		boolean_t lz4_ac = spa_feature_is_active(os->os_spa,
-		    ZIO_COMPRESS_LZJB;
+		    SPA_FEATURE_LZ4_COMPRESS);
+
+		if (zfs_mdcomp_disable) {
+			compress = ZIO_COMPRESS_EMPTY;
+		} else if (lz4_ac) {
+			compress = ZIO_COMPRESS_LZ4;
+		} else {
+			compress = ZIO_COMPRESS_LZJB;
+		}
 
 		/*
 		 * Metadata always gets checksummed.  If the data

sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c

@@ -22,7 +22,7 @@
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2011, 2014 by Delphix. All rights reserved.
- * Copyright 2013 Nexenta Systems, Inc.  All rights reserved.
+ * Copyright (c) 2013, 2014, Nexenta Systems, Inc.  All rights reserved.
  * Copyright (c) 2013 Martin Matuska <mm@FreeBSD.org>. All rights reserved.
  */
 
@@ -6425,6 +6425,22 @@ spa_sync_upgrades(spa_t *spa, dmu_tx_t *tx)
 	    spa->spa_uberblock.ub_version >= SPA_VERSION_FEATURES) {
 		spa_feature_create_zap_objects(spa, tx);
 	}
+
+	/*
+	 * LZ4_COMPRESS feature's behaviour was changed to activate_on_enable
+	 * when possibility to use lz4 compression for metadata was added
+	 * Old pools that have this feature enabled must be upgraded to have
+	 * this feature active
+	 */
+	if (spa->spa_uberblock.ub_version >= SPA_VERSION_FEATURES) {
+		boolean_t lz4_en = spa_feature_is_enabled(spa,
+		    SPA_FEATURE_LZ4_COMPRESS);
+		boolean_t lz4_ac = spa_feature_is_active(spa,
+		    SPA_FEATURE_LZ4_COMPRESS);
+
+		if (lz4_en && !lz4_ac)
+			spa_feature_incr(spa, SPA_FEATURE_LZ4_COMPRESS, tx);
+	}
 	rrw_exit(&dp->dp_config_rwlock, FTAG);
 }
 

sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ioctl.c

@@ -30,6 +30,7 @@
  * Copyright (c) 2013 by Delphix. All rights reserved.
  * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
  * Copyright (c) 2013 Steven Hartland. All rights reserved.
+ * Copyright (c) 2014, Nexenta Systems, Inc. All rights reserved.
  */
 
 /*
@@ -2504,37 +2505,6 @@ zfs_prop_set_special(const char *dsname, zprop_source_t source,
 		}
 		break;
 	}
-	case ZFS_PROP_COMPRESSION:
-	{
-		if (intval == ZIO_COMPRESS_LZ4) {
-			spa_t *spa;
-
-			if ((err = spa_open(dsname, &spa, FTAG)) != 0)
-				return (err);
-
-			/*
-			 * Setting the LZ4 compression algorithm activates
-			 * the feature.
-			 */
-			if (!spa_feature_is_active(spa,
-			    SPA_FEATURE_LZ4_COMPRESS)) {
-				if ((err = zfs_prop_activate_feature(spa,
-				    SPA_FEATURE_LZ4_COMPRESS)) != 0) {
-					spa_close(spa, FTAG);
-					return (err);
-				}
-			}
-
-			spa_close(spa, FTAG);
-		}
-		/*
-		 * We still want the default set action to be performed in the
-		 * caller, we only performed zfeature settings here.
-		 */
-		err = -1;
-		break;
-	}
-
 	default:
 		err = -1;
 	}