Illumos #1092: zfs refratio property

Add a "REFRATIO" property, which is the compression ratio based on
data referenced. For snapshots, this is the same as COMPRESSRATIO,
but for filesystems/volumes, the COMPRESSRATIO is based on the
data "USED" (ie, includes blocks in children, but not blocks
shared with the origin).

This is needed to figure out how much space a filesystem would
use if it were not compressed (ignoring snapshots).

Reviewed by: George Wilson <[email protected]>
Reviewed by: Adam Leventhal <[email protected]>
Reviewed by: Dan McDonald <[email protected]>
Reviewed by: Richard Elling <[email protected]>
Reviewed by: Mark Musante <[email protected]>
Reviewed by: Garrett D'Amore <[email protected]>
Approved by: Garrett D'Amore <[email protected]>

References to Illumos issue and patch:
- https://www.illumos.org/issues/1092
- https://github.com/illumos/illumos-gate/commit/187d6ac08a

Signed-off-by: Brian Behlendorf <[email protected]>
Issue #340

2 files changed, 12 insertions, 5 deletions

diff --git a/module/zcommon/zfs_prop.c b/module/zcommon/zfs_prop.c
index ce03a498c..9d65e35de 100644
--- a/module/zcommon/zfs_prop.c
+++ b/module/zcommon/zfs_prop.c
@@ -20,6 +20,7 @@
  */
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
  */
 
 /* Portions Copyright 2010 Robert Milkowski */
@@ -311,6 +312,9 @@ zfs_prop_init(void)
 	zprop_register_number(ZFS_PROP_COMPRESSRATIO, "compressratio", 0,
 	    PROP_READONLY, ZFS_TYPE_DATASET,
 	    "<1.00x or higher if compressed>", "RATIO");
+	zprop_register_number(ZFS_PROP_REFRATIO, "refcompressratio", 0,
+	    PROP_READONLY, ZFS_TYPE_DATASET,
+	    "<1.00x or higher if compressed>", "REFRATIO");
 	zprop_register_number(ZFS_PROP_VOLBLOCKSIZE, "volblocksize",
 	    ZVOL_DEFAULT_BLOCKSIZE, PROP_ONETIME,
 	    ZFS_TYPE_VOLUME, "512 to 128k, power of 2",	"VOLBLOCK");
diff --git a/module/zfs/dsl_dataset.c b/module/zfs/dsl_dataset.c
index c34ac2a76..26362c95c 100644
--- a/module/zfs/dsl_dataset.c
+++ b/module/zfs/dsl_dataset.c
@@ -20,6 +20,7 @@
  */
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011 by Delphix. All rights reserved.
  */
 
 #include <sys/dmu_objset.h>
@@ -2153,7 +2154,7 @@ dsl_dataset_sync(dsl_dataset_t *ds, zio_t *zio, dmu_tx_t *tx)
 void
 dsl_dataset_stats(dsl_dataset_t *ds, nvlist_t *nv)
 {
-	uint64_t refd, avail, uobjs, aobjs;
+	uint64_t refd, avail, uobjs, aobjs, ratio;
 
 	dsl_dir_stats(ds->ds_dir, nv);
 
@@ -2180,6 +2181,11 @@ dsl_dataset_stats(dsl_dataset_t *ds, nvlist_t *nv)
 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_DEFER_DESTROY,
 	    DS_IS_DEFER_DESTROY(ds) ? 1 : 0);
 
+	ratio = ds->ds_phys->ds_compressed_bytes == 0 ? 100 :
+	    (ds->ds_phys->ds_uncompressed_bytes * 100 /
+	    ds->ds_phys->ds_compressed_bytes);
+	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFRATIO, ratio);
+
 	if (ds->ds_phys->ds_next_snap_obj) {
 		/*
 		 * This is a snapshot; override the dd's space used with
@@ -2187,10 +2193,7 @@ dsl_dataset_stats(dsl_dataset_t *ds, nvlist_t *nv)
 		 */
 		dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USED,
 		    ds->ds_phys->ds_unique_bytes);
-		dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_COMPRESSRATIO,
-		    ds->ds_phys->ds_compressed_bytes == 0 ? 100 :
-		    (ds->ds_phys->ds_uncompressed_bytes * 100 /
-		    ds->ds_phys->ds_compressed_bytes));
+		dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_COMPRESSRATIO, ratio);
 	}
 }