Implement Redacted Send/Receive

Redacted send/receive allows users to send subsets of their data to 
a target system. One possible use case for this feature is to not 
transmit sensitive information to a data warehousing, test/dev, or 
analytics environment. Another is to save space by not replicating 
unimportant data within a given dataset, for example in backup tools 
like zrepl.

Redacted send/receive is a three-stage process. First, a clone (or 
clones) is made of the snapshot to be sent to the target. In this 
clone (or clones), all unnecessary or unwanted data is removed or
modified. This clone is then snapshotted to create the "redaction 
snapshot" (or snapshots). Second, the new zfs redact command is used 
to create a redaction bookmark. The redaction bookmark stores the 
list of blocks in a snapshot that were modified by the redaction 
snapshot(s). Finally, the redaction bookmark is passed as a parameter 
to zfs send. When sending to the snapshot that was redacted, the
redaction bookmark is used to filter out blocks that contain sensitive 
or unwanted information, and those blocks are not included in the send 
stream.  When sending from the redaction bookmark, the blocks it 
contains are considered as candidate blocks in addition to those 
blocks in the destination snapshot that were modified since the 
creation_txg of the redaction bookmark.  This step is necessary to 
allow the target to rehydrate data in the case where some blocks are 
accidentally or unnecessarily modified in the redaction snapshot.

The changes to bookmarks to enable fast space estimation involve 
adding deadlists to bookmarks. There is also logic to manage the 
life cycles of these deadlists.

The new size estimation process operates in cases where previously 
an accurate estimate could not be provided. In those cases, a send 
is performed where no data blocks are read, reducing the runtime 
significantly and providing a byte-accurate size estimate.

Reviewed-by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: Prashanth Sreenivasa <pks@delphix.com>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Reviewed-by: George Wilson <george.wilson@delphix.com>
Reviewed-by: Chris Williamson <chris.williamson@delphix.com>
Reviewed-by: Pavel Zhakarov <pavel.zakharov@delphix.com>
Reviewed-by: Sebastien Roy <sebastien.roy@delphix.com>
Reviewed-by: Prakash Surya <prakash.surya@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Paul Dagnelie <pcd@delphix.com>
Closes #7958

include/sys/dsl_dataset.h

@@ -45,11 +45,13 @@
 extern "C" {
 #endif
 
+extern int zfs_allow_redacted_dataset_mount;
 struct dsl_dataset;
 struct dsl_dir;
 struct dsl_pool;
 struct dsl_crypto_params;
 struct dsl_key_mapping;
+struct zfs_bookmark_phys;
 
 #define	DS_FLAG_INCONSISTENT	(1ULL<<0)
 #define	DS_IS_INCONSISTENT(ds)	\
@@ -114,6 +116,13 @@ struct dsl_key_mapping;
  */
 #define	DS_FIELD_REMAP_DEADLIST	"com.delphix:remap_deadlist"
 
+/*
+ * We were receiving an incremental from a redaction bookmark, and these are the
+ * guids of its snapshots.
+ */
+#define	DS_FIELD_RESUME_REDACT_BOOKMARK_SNAPS \
+	"com.delphix:resume_redact_book_snaps"
+
 /*
  * This field is set to the ivset guid for encrypted snapshots. This is used
  * for validating raw receives.
@@ -176,7 +185,8 @@ 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 */
+	uint64_t ds_bookmarks_obj;  /* DMU_OTN_ZAP_METADATA */
+	avl_tree_t ds_bookmarks; /* dsl_bookmark_node_t */
 
 	/* has internal locking: */
 	dsl_deadlist_t ds_deadlist;
@@ -314,23 +324,27 @@ int dsl_dataset_hold_flags(struct dsl_pool *dp, const char *name,
 boolean_t dsl_dataset_try_add_ref(struct dsl_pool *dp, dsl_dataset_t *ds,
     void *tag);
 int dsl_dataset_create_key_mapping(dsl_dataset_t *ds);
-int dsl_dataset_hold_obj(struct dsl_pool *dp, uint64_t dsobj, void *tag,
-    dsl_dataset_t **);
 int dsl_dataset_hold_obj_flags(struct dsl_pool *dp, uint64_t dsobj,
     ds_hold_flags_t flags, void *tag, dsl_dataset_t **);
 void dsl_dataset_remove_key_mapping(dsl_dataset_t *ds);
-void dsl_dataset_rele(dsl_dataset_t *ds, void *tag);
+int dsl_dataset_hold_obj(struct dsl_pool *dp, uint64_t dsobj,
+    void *tag, dsl_dataset_t **);
 void dsl_dataset_rele_flags(dsl_dataset_t *ds, ds_hold_flags_t flags,
     void *tag);
+void dsl_dataset_rele(dsl_dataset_t *ds, void *tag);
 int dsl_dataset_own(struct dsl_pool *dp, const char *name,
     ds_hold_flags_t flags, void *tag, dsl_dataset_t **dsp);
+int dsl_dataset_own_force(struct dsl_pool *dp, const char *name,
+    ds_hold_flags_t flags, void *tag, dsl_dataset_t **dsp);
 int dsl_dataset_own_obj(struct dsl_pool *dp, uint64_t dsobj,
     ds_hold_flags_t flags, void *tag, dsl_dataset_t **dsp);
+int dsl_dataset_own_obj_force(struct dsl_pool *dp, uint64_t dsobj,
+    ds_hold_flags_t flags, void *tag, dsl_dataset_t **dsp);
 void dsl_dataset_disown(dsl_dataset_t *ds, ds_hold_flags_t flags, void *tag);
 void dsl_dataset_name(dsl_dataset_t *ds, char *name);
+boolean_t dsl_dataset_tryown(dsl_dataset_t *ds, void *tag, boolean_t override);
 int dsl_dataset_namelen(dsl_dataset_t *ds);
 boolean_t dsl_dataset_has_owner(dsl_dataset_t *ds);
-boolean_t dsl_dataset_tryown(dsl_dataset_t *ds, void *tag);
 uint64_t dsl_dataset_create_sync(dsl_dir_t *pds, const char *lastname,
     dsl_dataset_t *origin, uint64_t flags, cred_t *,
     struct dsl_crypto_params *, dmu_tx_t *);
@@ -387,9 +401,11 @@ uint64_t dsl_get_defer_destroy(dsl_dataset_t *ds);
 uint64_t dsl_get_referenced(dsl_dataset_t *ds);
 uint64_t dsl_get_numclones(dsl_dataset_t *ds);
 uint64_t dsl_get_inconsistent(dsl_dataset_t *ds);
+uint64_t dsl_get_redacted(dsl_dataset_t *ds);
 uint64_t dsl_get_available(dsl_dataset_t *ds);
 int dsl_get_written(dsl_dataset_t *ds, uint64_t *written);
 int dsl_get_prev_snap(dsl_dataset_t *ds, char *snap);
+void dsl_get_redact_snaps(dsl_dataset_t *ds, nvlist_t *propval);
 int dsl_get_mountpoint(dsl_dataset_t *ds, const char *dsname, char *value,
     char *source);
 
@@ -403,6 +419,8 @@ void dsl_dataset_space(dsl_dataset_t *ds,
 uint64_t dsl_dataset_fsid_guid(dsl_dataset_t *ds);
 int dsl_dataset_space_written(dsl_dataset_t *oldsnap, dsl_dataset_t *new,
     uint64_t *usedp, uint64_t *compp, uint64_t *uncompp);
+int dsl_dataset_space_written_bookmark(struct zfs_bookmark_phys *bmp,
+    dsl_dataset_t *new, uint64_t *usedp, uint64_t *compp, uint64_t *uncompp);
 int dsl_dataset_space_wouldfree(dsl_dataset_t *firstsnap, dsl_dataset_t *last,
     uint64_t *usedp, uint64_t *compp, uint64_t *uncompp);
 
@@ -463,6 +481,9 @@ boolean_t dsl_dataset_feature_is_active(dsl_dataset_t *ds, spa_feature_t f);
 boolean_t dsl_dataset_get_uint64_array_feature(dsl_dataset_t *ds,
     spa_feature_t f, uint64_t *outlength, uint64_t **outp);
 
+void dsl_dataset_activate_redaction(dsl_dataset_t *ds, uint64_t *redact_snaps,
+    uint64_t num_redact_snaps, dmu_tx_t *tx);
+
 #ifdef ZFS_DEBUG
 #define	dprintf_ds(ds, fmt, ...) do { \
 	if (zfs_flags & ZFS_DEBUG_DPRINTF) { \