8155 simplify dmu_write_policy handling of pre-compressed buffers

Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Approved by: Robert Mustacchi <rm@joyent.com>

5 files changed, 17 insertions, 25 deletions

diff --git a/usr/src/uts/common/fs/zfs/arc.c b/usr/src/uts/common/fs/zfs/arc.c
index 328c332ae4..1b4542ce01 100644
--- a/usr/src/uts/common/fs/zfs/arc.c
+++ b/usr/src/uts/common/fs/zfs/arc.c
@@ -5607,6 +5607,7 @@ arc_write(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp, arc_buf_t *buf,
 	arc_buf_hdr_t *hdr = buf->b_hdr;
 	arc_write_callback_t *callback;
 	zio_t *zio;
+	zio_prop_t localprop = *zp;
 
 	ASSERT3P(ready, !=, NULL);
 	ASSERT3P(done, !=, NULL);
@@ -5617,7 +5618,13 @@ arc_write(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp, arc_buf_t *buf,
 	if (l2arc)
 		arc_hdr_set_flags(hdr, ARC_FLAG_L2CACHE);
 	if (ARC_BUF_COMPRESSED(buf)) {
-		ASSERT3U(zp->zp_compress, !=, ZIO_COMPRESS_OFF);
+		/*
+		 * We're writing a pre-compressed buffer.  Make the
+		 * compression algorithm requested by the zio_prop_t match
+		 * the pre-compressed buffer's compression algorithm.
+		 */
+		localprop.zp_compress = HDR_GET_COMPRESS(hdr);
+
 		ASSERT3U(HDR_GET_LSIZE(hdr), !=, arc_buf_size(buf));
 		zio_flags |= ZIO_FLAG_RAW;
 	}
@@ -5653,7 +5660,7 @@ arc_write(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp, arc_buf_t *buf,
 
 	zio = zio_write(pio, spa, txg, bp,
 	    abd_get_from_buf(buf->b_data, HDR_GET_LSIZE(hdr)),
-	    HDR_GET_LSIZE(hdr), arc_buf_size(buf), zp, arc_write_ready,
+	    HDR_GET_LSIZE(hdr), arc_buf_size(buf), &localprop, arc_write_ready,
 	    (children_ready != NULL) ? arc_write_children_ready : NULL,
 	    arc_write_physdone, arc_write_done, callback,
 	    priority, zio_flags, zb);
diff --git a/usr/src/uts/common/fs/zfs/dbuf.c b/usr/src/uts/common/fs/zfs/dbuf.c
index 85699a7731..23d4d3b0bf 100644
--- a/usr/src/uts/common/fs/zfs/dbuf.c
+++ b/usr/src/uts/common/fs/zfs/dbuf.c
@@ -3535,9 +3535,7 @@ dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx)
 		wp_flag = WP_SPILL;
 	wp_flag |= (db->db_state == DB_NOFILL) ? WP_NOFILL : 0;
 
-	dmu_write_policy(os, dn, db->db_level, wp_flag,
-	    (data != NULL && arc_get_compression(data) != ZIO_COMPRESS_OFF) ?
-	    arc_get_compression(data) : ZIO_COMPRESS_INHERIT, &zp);
+	dmu_write_policy(os, dn, db->db_level, wp_flag, &zp);
 	DB_DNODE_EXIT(db);
 
 	/*
diff --git a/usr/src/uts/common/fs/zfs/dmu.c b/usr/src/uts/common/fs/zfs/dmu.c
index 20a41cc98e..5fafb95c79 100644
--- a/usr/src/uts/common/fs/zfs/dmu.c
+++ b/usr/src/uts/common/fs/zfs/dmu.c
@@ -20,7 +20,7 @@
  */
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2011, 2016 by Delphix. All rights reserved.
+ * Copyright (c) 2011, 2017 by Delphix. All rights reserved.
  */
 /* Copyright (c) 2013 by Saso Kiselkov. All rights reserved. */
 /* Copyright (c) 2013, Joyent, Inc. All rights reserved. */
@@ -1713,8 +1713,7 @@ dmu_sync(zio_t *pio, uint64_t txg, dmu_sync_cb_t *done, zgd_t *zgd)
 
 	DB_DNODE_ENTER(db);
 	dn = DB_DNODE(db);
-	dmu_write_policy(os, dn, db->db_level, WP_DMU_SYNC,
-	    ZIO_COMPRESS_INHERIT, &zp);
+	dmu_write_policy(os, dn, db->db_level, WP_DMU_SYNC, &zp);
 	DB_DNODE_EXIT(db);
 
 	/*
@@ -1884,8 +1883,7 @@ int zfs_mdcomp_disable = 0;
 int zfs_redundant_metadata_most_ditto_level = 2;
 
 void
-dmu_write_policy(objset_t *os, dnode_t *dn, int level, int wp,
-    enum zio_compress override_compress, zio_prop_t *zp)
+dmu_write_policy(objset_t *os, dnode_t *dn, int level, int wp, zio_prop_t *zp)
 {
 	dmu_object_type_t type = dn ? dn->dn_type : DMU_OT_OBJSET;
 	boolean_t ismd = (level > 0 || DMU_OT_IS_METADATA(type) ||
@@ -1897,10 +1895,6 @@ dmu_write_policy(objset_t *os, dnode_t *dn, int level, int wp,
 	boolean_t nopwrite = B_FALSE;
 	boolean_t dedup_verify = os->os_dedup_verify;
 	int copies = os->os_copies;
-	boolean_t lz4_ac = spa_feature_is_active(os->os_spa,
-	    SPA_FEATURE_LZ4_COMPRESS);
-
-	IMPLY(override_compress == ZIO_COMPRESS_LZ4, lz4_ac);
 
 	/*
 	 * We maintain different write policies for each of the following
@@ -1988,14 +1982,7 @@ dmu_write_policy(objset_t *os, dnode_t *dn, int level, int wp,
 	}
 
 	zp->zp_checksum = checksum;
-
-	/*
-	 * If we're writing a pre-compressed buffer, the compression type we use
-	 * must match the data. If it hasn't been compressed yet, then we should
-	 * use the value dictated by the policies above.
-	 */
-	zp->zp_compress = override_compress != ZIO_COMPRESS_INHERIT
-	    ? override_compress : compress;
+	zp->zp_compress = compress;
 	ASSERT3U(zp->zp_compress, !=, ZIO_COMPRESS_INHERIT);
 
 	zp->zp_type = (wp & WP_SPILL) ? dn->dn_bonustype : type;
diff --git a/usr/src/uts/common/fs/zfs/dmu_objset.c b/usr/src/uts/common/fs/zfs/dmu_objset.c
index 7e5ef03983..6bf61854b7 100644
--- a/usr/src/uts/common/fs/zfs/dmu_objset.c
+++ b/usr/src/uts/common/fs/zfs/dmu_objset.c
@@ -1201,7 +1201,7 @@ dmu_objset_sync(objset_t *os, zio_t *pio, dmu_tx_t *tx)
 	    ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
 	arc_release(os->os_phys_buf, &os->os_phys_buf);
 
-	dmu_write_policy(os, NULL, 0, 0, ZIO_COMPRESS_INHERIT, &zp);
+	dmu_write_policy(os, NULL, 0, 0, &zp);
 
 	zio = arc_write(pio, os->os_spa, tx->tx_txg,
 	    blkptr_copy, os->os_phys_buf, DMU_OS_IS_L2CACHEABLE(os),
diff --git a/usr/src/uts/common/fs/zfs/sys/dmu.h b/usr/src/uts/common/fs/zfs/sys/dmu.h
index 7eb6549cce..1dba052ae0 100644
--- a/usr/src/uts/common/fs/zfs/sys/dmu.h
+++ b/usr/src/uts/common/fs/zfs/sys/dmu.h
@@ -21,7 +21,7 @@
 
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2011, 2016 by Delphix. All rights reserved.
+ * Copyright (c) 2011, 2017 by Delphix. All rights reserved.
  * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
  * Copyright (c) 2012, Joyent, Inc. All rights reserved.
  * Copyright 2013 DEY Storage Systems, Inc.
@@ -420,7 +420,7 @@ dmu_write_embedded(objset_t *os, uint64_t object, uint64_t offset,
 #define	WP_SPILL	0x4
 
 void dmu_write_policy(objset_t *os, dnode_t *dn, int level, int wp,
-    enum zio_compress compress_override, struct zio_prop *zp);
+    struct zio_prop *zp);
 /*
  * The bonus data is accessed more or less like a regular buffer.
  * You must dmu_bonus_hold() to get the buffer, which will give you a