Illumos 5661 - ZFS: "compression = on" should use lz4 if feature is enabled

5661 ZFS: "compression = on" should use lz4 if feature is enabled
Reviewed by: Matthew Ahrens <[email protected]>
Reviewed by: Josef 'Jeff' Sipek <[email protected]>
Reviewed by: Xin LI <[email protected]>
Approved by: Robert Mustacchi <[email protected]>

References:
  https://github.com/illumos/illumos-gate/commit/db1741f
  https://www.illumos.org/issues/5661

Ported-by: kernelOfTruth [email protected]
Signed-off-by: Brian Behlendorf <[email protected]>
Closes #3571

3 files changed, 27 insertions, 20 deletions

diff --git a/module/zfs/dmu.c b/module/zfs/dmu.c
index 7e8328e77..7d3945433 100644
--- a/module/zfs/dmu.c
+++ b/module/zfs/dmu.c
@@ -1864,19 +1864,15 @@ dmu_write_policy(objset_t *os, dnode_t *dn, int level, int wp, zio_prop_t *zp)
 	 *	 3. all other level 0 blocks
 	 */
 	if (ismd) {
-		/*
-		 * XXX -- we should design a compression algorithm
-		 * that specializes in arrays of bps.
-		 */
-		boolean_t lz4_ac = spa_feature_is_active(os->os_spa,
-		    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;
+			/*
+			 * XXX -- we should design a compression algorithm
+			 * that specializes in arrays of bps.
+			 */
+			compress = zio_compress_select(os->os_spa,
+			    ZIO_COMPRESS_ON, ZIO_COMPRESS_ON);
 		}
 
 		/*
@@ -1909,7 +1905,8 @@ dmu_write_policy(objset_t *os, dnode_t *dn, int level, int wp, zio_prop_t *zp)
 		compress = ZIO_COMPRESS_OFF;
 		checksum = ZIO_CHECKSUM_OFF;
 	} else {
-		compress = zio_compress_select(dn->dn_compress, compress);
+		compress = zio_compress_select(os->os_spa, dn->dn_compress,
+		    compress);
 
 		checksum = (dedup_checksum == ZIO_CHECKSUM_OFF) ?
 		    zio_checksum_select(dn->dn_checksum, checksum) :
diff --git a/module/zfs/dmu_objset.c b/module/zfs/dmu_objset.c
index 823a15677..bd953dc36 100644
--- a/module/zfs/dmu_objset.c
+++ b/module/zfs/dmu_objset.c
@@ -163,7 +163,8 @@ compression_changed_cb(void *arg, uint64_t newval)
 	 */
 	ASSERT(newval != ZIO_COMPRESS_INHERIT);
 
-	os->os_compress = zio_compress_select(newval, ZIO_COMPRESS_ON_VALUE);
+	os->os_compress = zio_compress_select(os->os_spa, newval,
+	    ZIO_COMPRESS_ON);
 }
 
 static void
@@ -420,7 +421,7 @@ dmu_objset_open_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp,
 	} else {
 		/* It's the meta-objset. */
 		os->os_checksum = ZIO_CHECKSUM_FLETCHER_4;
-		os->os_compress = ZIO_COMPRESS_LZJB;
+		os->os_compress = ZIO_COMPRESS_ON;
 		os->os_copies = spa_max_replication(spa);
 		os->os_dedup_checksum = ZIO_CHECKSUM_OFF;
 		os->os_dedup_verify = B_FALSE;
diff --git a/module/zfs/zio_compress.c b/module/zfs/zio_compress.c
index 074462349..6b8d6c39b 100644
--- a/module/zfs/zio_compress.c
+++ b/module/zfs/zio_compress.c
@@ -34,6 +34,7 @@
 #include <sys/zfs_context.h>
 #include <sys/compress.h>
 #include <sys/spa.h>
+#include <sys/zfeature.h>
 #include <sys/zio.h>
 #include <sys/zio_compress.h>
 
@@ -61,19 +62,27 @@ zio_compress_info_t zio_compress_table[ZIO_COMPRESS_FUNCTIONS] = {
 };
 
 enum zio_compress
-zio_compress_select(enum zio_compress child, enum zio_compress parent)
+zio_compress_select(spa_t *spa, enum zio_compress child,
+    enum zio_compress parent)
 {
+	enum zio_compress result;
+
 	ASSERT(child < ZIO_COMPRESS_FUNCTIONS);
 	ASSERT(parent < ZIO_COMPRESS_FUNCTIONS);
-	ASSERT(parent != ZIO_COMPRESS_INHERIT && parent != ZIO_COMPRESS_ON);
+	ASSERT(parent != ZIO_COMPRESS_INHERIT);
 
-	if (child == ZIO_COMPRESS_INHERIT)
-		return (parent);
+	result = child;
+	if (result == ZIO_COMPRESS_INHERIT)
+		result = parent;
 
-	if (child == ZIO_COMPRESS_ON)
-		return (ZIO_COMPRESS_ON_VALUE);
+	if (result == ZIO_COMPRESS_ON) {
+		if (spa_feature_is_active(spa, SPA_FEATURE_LZ4_COMPRESS))
+			result = ZIO_COMPRESS_LZ4_ON_VALUE;
+		else
+			result = ZIO_COMPRESS_LEGACY_ON_VALUE;
+	}
 
-	return (child);
+	return (result);
 }
 
 size_t