Illumos 5959 - clean up per-dataset feature count code

5959 clean up per-dataset feature count code
Reviewed by: Toomas Soome <[email protected]>
Reviewed by: George Wilson <[email protected]>
Reviewed by: Alex Reece <[email protected]>
Approved by: Richard Lowe <[email protected]>

References:
  https://www.illumos.org/issues/5959
  https://github.com/illumos/illumos-gate/commit/ca0cc39

Porting notes:

illumos code doesn't check for feature_get_refcount() returning
ENOTSUP (which means feature is disabled) in zdb. zfsonlinux added
a check in https://github.com/zfsonlinux/zfs/commit/784652c
due to #3468. The check was reintroduced here.

Ported-by: Witaut Bajaryn <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>
Closes #3965

2 files changed, 30 insertions, 10 deletions

diff --git a/include/sys/dsl_dataset.h b/include/sys/dsl_dataset.h
index d6da5dcfd..25622263e 100644
--- a/include/sys/dsl_dataset.h
+++ b/include/sys/dsl_dataset.h
@@ -20,7 +20,7 @@
  */
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2013 by Delphix. All rights reserved.
+ * Copyright (c) 2011, 2015 by Delphix. All rights reserved.
  * Copyright (c) 2013, Joyent, Inc. All rights reserved.
  * Copyright (c) 2013 Steven Hartland. All rights reserved.
  * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
@@ -38,6 +38,7 @@
 #include <sys/zfs_context.h>
 #include <sys/dsl_deadlist.h>
 #include <sys/refcount.h>
+#include <zfeature_common.h>
 
 #ifdef	__cplusplus
 extern "C" {
@@ -145,8 +146,6 @@ typedef struct dsl_dataset {
 	/* only used in syncing context, only valid for non-snapshots: */
 	struct dsl_dataset *ds_prev;
 	uint64_t ds_bookmarks;  /* DMU_OTN_ZAP_METADATA */
-	boolean_t ds_large_blocks;
-	boolean_t ds_need_large_blocks;
 
 	/* has internal locking: */
 	dsl_deadlist_t ds_deadlist;
@@ -185,6 +184,18 @@ typedef struct dsl_dataset {
 	kmutex_t ds_sendstream_lock;
 	list_t ds_sendstreams;
 
+	/*
+	 * For ZFEATURE_FLAG_PER_DATASET features, set if this dataset
+	 * uses this feature.
+	 */
+	uint8_t ds_feature_inuse[SPA_FEATURES];
+
+	/*
+	 * Set if we need to activate the feature on this dataset this txg
+	 * (used only in syncing context).
+	 */
+	uint8_t ds_feature_activation_needed[SPA_FEATURES];
+
 	/* Protected by ds_lock; keep at end of struct for better locality */
 	char ds_snapname[MAXNAMELEN];
 } dsl_dataset_t;
@@ -264,8 +275,6 @@ int dsl_dataset_space_written(dsl_dataset_t *oldsnap, dsl_dataset_t *new,
 int dsl_dataset_space_wouldfree(dsl_dataset_t *firstsnap, dsl_dataset_t *last,
     uint64_t *usedp, uint64_t *compp, uint64_t *uncompp);
 boolean_t dsl_dataset_is_dirty(dsl_dataset_t *ds);
-int dsl_dataset_activate_large_blocks(const char *dsname);
-void dsl_dataset_activate_large_blocks_sync_impl(uint64_t dsobj, dmu_tx_t *tx);
 
 int dsl_dsobj_to_dsname(char *pname, uint64_t obj, char *buf);
 
@@ -305,6 +314,9 @@ void dsl_dataset_set_refreservation_sync_impl(dsl_dataset_t *ds,
 void dsl_dataset_zapify(dsl_dataset_t *ds, dmu_tx_t *tx);
 int dsl_dataset_rollback(const char *fsname, void *owner, nvlist_t *result);
 
+void dsl_dataset_deactivate_feature(uint64_t dsobj,
+    spa_feature_t f, dmu_tx_t *tx);
+
 #ifdef ZFS_DEBUG
 #define	dprintf_ds(ds, fmt, ...) do { \
 	if (zfs_flags & ZFS_DEBUG_DPRINTF) { \
diff --git a/include/zfeature_common.h b/include/zfeature_common.h
index e383c4ff7..d481a28a8 100644
--- a/include/zfeature_common.h
+++ b/include/zfeature_common.h
@@ -20,7 +20,7 @@
  */
 
 /*
- * Copyright (c) 2013 by Delphix. All rights reserved.
+ * Copyright (c) 2011, 2015 by Delphix. All rights reserved.
  * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
  */
 
@@ -55,15 +55,23 @@ typedef enum spa_feature {
 
 #define	SPA_FEATURE_DISABLED	(-1ULL)
 
+typedef enum zfeature_flags {
+	/* Can open pool readonly even if this feature is not supported. */
+	ZFEATURE_FLAG_READONLY_COMPAT =		(1 << 0),
+	/* Is this feature necessary to read the MOS? */
+	ZFEATURE_FLAG_MOS =			(1 << 1),
+	/* Activate this feature at the same time it is enabled. */
+	ZFEATURE_FLAG_ACTIVATE_ON_ENABLE =	(1 << 2),
+	/* Each dataset has a field set if it has ever used this feature. */
+	ZFEATURE_FLAG_PER_DATASET =		(1 << 3)
+} zfeature_flags_t;
+
 typedef struct zfeature_info {
 	spa_feature_t fi_feature;
 	const char *fi_uname;	/* User-facing feature name */
 	const char *fi_guid;	/* On-disk feature identifier */
 	const char *fi_desc;	/* Feature description */
-	boolean_t fi_can_readonly; /* Can open pool readonly w/o support? */
-	boolean_t fi_mos;	/* Is the feature necessary to read the MOS? */
-	/* Activate this feature at the same time it is enabled */
-	boolean_t fi_activate_on_enable;
+	zfeature_flags_t fi_flags;
 	/* array of dependencies, terminated by SPA_FEATURE_NONE */
 	const spa_feature_t *fi_depends;
 } zfeature_info_t;