Add options to zfs redundant_metadata property

Currently, additional/extra copies are created for metadata in
addition to the redundancy provided by the pool(mirror/raidz/draid),
due to this 2 times more space is utilized per inode and this decreases
the total number of inodes that can be created in the filesystem. By
setting redundant_metadata to none, no additional copies of metadata
are created, hence can reduce the space consumed by the additional
metadata copies and increase the total number of inodes that can be
created in the filesystem.  Additionally, this can improve file create
performance due to the reduced amount of metadata which needs
to be written.

Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Dipak Ghosh <[email protected]>
Signed-off-by: Akash B <[email protected]>
Closes #13680

1 files changed, 92 insertions, 0 deletions

diff --git a/module/zfs/dsl_prop.c b/module/zfs/dsl_prop.c
index 610e887b3..ad927b622 100644
--- a/module/zfs/dsl_prop.c
+++ b/module/zfs/dsl_prop.c
@@ -23,6 +23,7 @@
  * Copyright (c) 2012, 2015 by Delphix. All rights reserved.
  * Copyright (c) 2013 Martin Matuska. All rights reserved.
  * Copyright 2019 Joyent, Inc.
+ * Copyright (c) 2022 Hewlett Packard Enterprise Development LP.
  */
 
 #include <sys/zfs_context.h>
@@ -41,6 +42,7 @@
 
 #define	ZPROP_INHERIT_SUFFIX "$inherit"
 #define	ZPROP_RECVD_SUFFIX "$recvd"
+#define	ZPROP_IUV_SUFFIX "$iuv"
 
 static int
 dodefault(zfs_prop_t prop, int intsz, int numints, void *buf)
@@ -69,6 +71,16 @@ dodefault(zfs_prop_t prop, int intsz, int numints, void *buf)
 	return (0);
 }
 
+static int
+dsl_prop_known_index(zfs_prop_t prop, uint64_t value)
+{
+	const char *str = NULL;
+	if (zfs_prop_get_type(prop) == PROP_TYPE_INDEX)
+		return (!zfs_prop_index_to_string(prop, value, &str));
+
+	return (-1);
+}
+
 int
 dsl_prop_get_dd(dsl_dir_t *dd, const char *propname,
     int intsz, int numints, void *buf, char *setpoint, boolean_t snapshot)
@@ -81,6 +93,7 @@ dsl_prop_get_dd(dsl_dir_t *dd, const char *propname,
 	boolean_t inheriting = B_FALSE;
 	char *inheritstr;
 	char *recvdstr;
+	char *iuvstr;
 
 	ASSERT(dsl_pool_config_held(dd->dd_pool));
 
@@ -91,6 +104,7 @@ dsl_prop_get_dd(dsl_dir_t *dd, const char *propname,
 	inheritable = (prop == ZPROP_USERPROP || zfs_prop_inheritable(prop));
 	inheritstr = kmem_asprintf("%s%s", propname, ZPROP_INHERIT_SUFFIX);
 	recvdstr = kmem_asprintf("%s%s", propname, ZPROP_RECVD_SUFFIX);
+	iuvstr = kmem_asprintf("%s%s", propname, ZPROP_IUV_SUFFIX);
 
 	/*
 	 * Note: dd may become NULL, therefore we shouldn't dereference it
@@ -105,6 +119,18 @@ dsl_prop_get_dd(dsl_dir_t *dd, const char *propname,
 			inheriting = B_TRUE;
 		}
 
+		/* Check for a iuv value. */
+		err = zap_lookup(mos, dsl_dir_phys(dd)->dd_props_zapobj,
+		    iuvstr, intsz, numints, buf);
+		if (dsl_prop_known_index(zfs_name_to_prop(propname),
+		    *(uint64_t *)buf) != 1)
+			err = ENOENT;
+		if (err != ENOENT) {
+			if (setpoint != NULL && err == 0)
+				dsl_dir_name(dd, setpoint);
+			break;
+		}
+
 		/* Check for a local value. */
 		err = zap_lookup(mos, dsl_dir_phys(dd)->dd_props_zapobj,
 		    propname, intsz, numints, buf);
@@ -155,6 +181,7 @@ dsl_prop_get_dd(dsl_dir_t *dd, const char *propname,
 
 	kmem_strfree(inheritstr);
 	kmem_strfree(recvdstr);
+	kmem_strfree(iuvstr);
 
 	return (err);
 }
@@ -647,6 +674,45 @@ dsl_prop_changed_notify(dsl_pool_t *dp, uint64_t ddobj,
 	dsl_dir_rele(dd, FTAG);
 }
 
+
+/*
+ * For newer values in zfs index type properties, we add a new key
+ * propname$iuv (iuv = Ignore Unknown Values) to the properties zap object
+ * to store the new property value and store the default value in the
+ * existing prop key. So that the propname$iuv key is ignored by the older zfs
+ * versions and the default property value from the existing prop key is
+ * used.
+ */
+static void
+dsl_prop_set_iuv(objset_t *mos, uint64_t zapobj, const char *propname,
+    int intsz, int numints, const void *value, dmu_tx_t *tx)
+{
+	char *iuvstr = kmem_asprintf("%s%s", propname, ZPROP_IUV_SUFFIX);
+	boolean_t iuv = B_FALSE;
+	zfs_prop_t prop = zfs_name_to_prop(propname);
+
+	switch (prop) {
+	case ZFS_PROP_REDUNDANT_METADATA:
+		if (*(uint64_t *)value == ZFS_REDUNDANT_METADATA_SOME ||
+		    *(uint64_t *)value == ZFS_REDUNDANT_METADATA_NONE)
+			iuv = B_TRUE;
+		break;
+	default:
+		break;
+	}
+
+	if (iuv) {
+		VERIFY0(zap_update(mos, zapobj, iuvstr, intsz, numints,
+		    value, tx));
+		uint64_t val = zfs_prop_default_numeric(prop);
+		VERIFY0(zap_update(mos, zapobj, propname, intsz, numints,
+		    &val, tx));
+	} else {
+		zap_remove(mos, zapobj, iuvstr, tx);
+	}
+	kmem_strfree(iuvstr);
+}
+
 void
 dsl_prop_set_sync_impl(dsl_dataset_t *ds, const char *propname,
     zprop_source_t source, int intsz, int numints, const void *value,
@@ -659,6 +725,7 @@ dsl_prop_set_sync_impl(dsl_dataset_t *ds, const char *propname,
 	const char *valstr = NULL;
 	char *inheritstr;
 	char *recvdstr;
+	char *iuvstr;
 	char *tbuf = NULL;
 	int err;
 	uint64_t version = spa_version(ds->ds_dir->dd_pool->dp_spa);
@@ -692,6 +759,7 @@ dsl_prop_set_sync_impl(dsl_dataset_t *ds, const char *propname,
 
 	inheritstr = kmem_asprintf("%s%s", propname, ZPROP_INHERIT_SUFFIX);
 	recvdstr = kmem_asprintf("%s%s", propname, ZPROP_RECVD_SUFFIX);
+	iuvstr = kmem_asprintf("%s%s", propname, ZPROP_IUV_SUFFIX);
 
 	switch ((int)source) {
 	case ZPROP_SRC_NONE:
@@ -709,11 +777,14 @@ dsl_prop_set_sync_impl(dsl_dataset_t *ds, const char *propname,
 		/*
 		 * remove propname$inherit
 		 * set propname -> value
+		 * set propname$iuv -> new property value
 		 */
 		err = zap_remove(mos, zapobj, inheritstr, tx);
 		ASSERT(err == 0 || err == ENOENT);
 		VERIFY0(zap_update(mos, zapobj, propname,
 		    intsz, numints, value, tx));
+		(void) dsl_prop_set_iuv(mos, zapobj, propname, intsz,
+		    numints, value, tx);
 		break;
 	case ZPROP_SRC_INHERITED:
 		/*
@@ -723,6 +794,8 @@ dsl_prop_set_sync_impl(dsl_dataset_t *ds, const char *propname,
 		 */
 		err = zap_remove(mos, zapobj, propname, tx);
 		ASSERT(err == 0 || err == ENOENT);
+		err = zap_remove(mos, zapobj, iuvstr, tx);
+		ASSERT(err == 0 || err == ENOENT);
 		if (version >= SPA_VERSION_RECVD_PROPS &&
 		    dsl_prop_get_int_ds(ds, ZPROP_HAS_RECVD, &dummy) == 0) {
 			dummy = 0;
@@ -763,6 +836,7 @@ dsl_prop_set_sync_impl(dsl_dataset_t *ds, const char *propname,
 
 	kmem_strfree(inheritstr);
 	kmem_strfree(recvdstr);
+	kmem_strfree(iuvstr);
 
 	/*
 	 * If we are left with an empty snap zap we can destroy it.
@@ -1012,6 +1086,14 @@ dsl_prop_get_all_impl(objset_t *mos, uint64_t propobj,
 
 			propname = za.za_name;
 			source = setpoint;
+
+			/* Skip if iuv entries are preset. */
+			valstr = kmem_asprintf("%s%s", propname,
+			    ZPROP_IUV_SUFFIX);
+			err = zap_contains(mos, propobj, valstr);
+			kmem_strfree(valstr);
+			if (err == 0)
+				continue;
 		} else if (strcmp(suffix, ZPROP_INHERIT_SUFFIX) == 0) {
 			/* Skip explicitly inherited entries. */
 			continue;
@@ -1044,6 +1126,16 @@ dsl_prop_get_all_impl(objset_t *mos, uint64_t propobj,
 
 			source = ((flags & DSL_PROP_GET_INHERITING) ?
 			    setpoint : ZPROP_SOURCE_VAL_RECVD);
+		} else if (strcmp(suffix, ZPROP_IUV_SUFFIX) == 0) {
+			(void) strlcpy(buf, za.za_name,
+			    MIN(sizeof (buf), suffix - za.za_name + 1));
+			propname = buf;
+			source = setpoint;
+			prop = zfs_name_to_prop(propname);
+
+			if (dsl_prop_known_index(prop,
+			    za.za_first_integer) != 1)
+				continue;
 		} else {
 			/*
 			 * For backward compatibility, skip suffixes we don't