Illumos #2882, #2883, #2900

2882 implement libzfs_core
2883 changing "canmount" property to "on" should not always remount dataset
2900 "zfs snapshot" should be able to create multiple, arbitrary snapshots at once

Reviewed by: George Wilson <[email protected]>
Reviewed by: Chris Siden <[email protected]>
Reviewed by: Garrett D'Amore <[email protected]>
Reviewed by: Bill Pijewski <[email protected]>
Reviewed by: Dan Kruchinin <[email protected]>
Approved by: Eric Schrock <[email protected]>

References:
  https://www.illumos.org/issues/2882
  https://www.illumos.org/issues/2883
  https://www.illumos.org/issues/2900
  illumos/illumos-gate@4445fffbbb1ea25fd0e9ea68b9380dd7a6709025

Ported-by: Tim Chase <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>
Closes #1293

Porting notes:

WARNING: This patch changes the user/kernel ABI.  That means that
the zfs/zpool utilities built from master are NOT compatible with
the 0.6.2 kernel modules.  Ensure you load the matching kernel
modules from master after updating the utilities.  Otherwise the
zfs/zpool commands will be unable to interact with your pool and
you will see errors similar to the following:

  $ zpool list
  failed to read pool configuration: bad address
  no pools available

  $ zfs list
  no datasets available

Add zvol minor device creation to the new zfs_snapshot_nvl function.

Remove the logging of the "release" operation in
dsl_dataset_user_release_sync().  The logging caused a null dereference
because ds->ds_dir is zeroed in dsl_dataset_destroy_sync() and the
logging functions try to get the ds name via the dsl_dataset_name()
function. I've got no idea why this particular code would have worked
in Illumos.  This code has subsequently been completely reworked in
Illumos commit 3b2aab1 (3464 zfs synctask code needs restructuring).

Squash some "may be used uninitialized" warning/erorrs.

Fix some printf format warnings for %lld and %llu.

Apply a few spa_writeable() changes that were made to Illumos in
illumos/illumos-gate.git@cd1c8b8 as part of the 3112, 3113, 3114 and
3115 fixes.

Add a missing call to fnvlist_free(nvl) in log_internal() that was added
in Illumos to fix issue 3085 but couldn't be ported to ZoL at the time
(zfsonlinux/zfs@9e11c73) because it depended on future work.

1 files changed, 56 insertions, 54 deletions

diff --git a/module/zfs/dmu_send.c b/module/zfs/dmu_send.c
index 54e75971d..6552e1d9d 100644
--- a/module/zfs/dmu_send.c
+++ b/module/zfs/dmu_send.c
@@ -416,9 +416,48 @@ backup_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
 	return (err);
 }
 
+/*
+ * Return TRUE if 'earlier' is an earlier snapshot in 'later's timeline.
+ * For example, they could both be snapshots of the same filesystem, and
+ * 'earlier' is before 'later'.  Or 'earlier' could be the origin of
+ * 'later's filesystem.  Or 'earlier' could be an older snapshot in the origin's
+ * filesystem.  Or 'earlier' could be the origin's origin.
+ */
+static boolean_t
+is_before(dsl_dataset_t *later, dsl_dataset_t *earlier)
+{
+	dsl_pool_t *dp = later->ds_dir->dd_pool;
+	int error;
+	boolean_t ret;
+	dsl_dataset_t *origin;
+
+	if (earlier->ds_phys->ds_creation_txg >=
+	    later->ds_phys->ds_creation_txg)
+		return (B_FALSE);
+
+	if (later->ds_dir == earlier->ds_dir)
+		return (B_TRUE);
+	if (!dsl_dir_is_clone(later->ds_dir))
+		return (B_FALSE);
+
+	rw_enter(&dp->dp_config_rwlock, RW_READER);
+	if (later->ds_dir->dd_phys->dd_origin_obj == earlier->ds_object) {
+		rw_exit(&dp->dp_config_rwlock);
+		return (B_TRUE);
+	}
+	error = dsl_dataset_hold_obj(dp,
+	    later->ds_dir->dd_phys->dd_origin_obj, FTAG, &origin);
+	rw_exit(&dp->dp_config_rwlock);
+	if (error != 0)
+		return (B_FALSE);
+	ret = is_before(origin, earlier);
+	dsl_dataset_rele(origin, FTAG);
+	return (ret);
+}
+
 int
-dmu_send(objset_t *tosnap, objset_t *fromsnap, boolean_t fromorigin,
-    int outfd, vnode_t *vp, offset_t *off)
+dmu_send(objset_t *tosnap, objset_t *fromsnap, int outfd, vnode_t *vp,
+    offset_t *off)
 {
 	dsl_dataset_t *ds = tosnap->os_dsl_dataset;
 	dsl_dataset_t *fromds = fromsnap ? fromsnap->os_dsl_dataset : NULL;
@@ -431,30 +470,13 @@ dmu_send(objset_t *tosnap, objset_t *fromsnap, boolean_t fromorigin,
 	if (ds->ds_phys->ds_next_snap_obj == 0)
 		return (EINVAL);
 
-	/* fromsnap must be an earlier snapshot from the same fs as tosnap */
-	if (fromds && (ds->ds_dir != fromds->ds_dir ||
-	    fromds->ds_phys->ds_creation_txg >= ds->ds_phys->ds_creation_txg))
+	/*
+	 * fromsnap must be an earlier snapshot from the same fs as tosnap,
+	 * or the origin's fs.
+	 */
+	if (fromds != NULL && !is_before(ds, fromds))
 		return (EXDEV);
 
-	if (fromorigin) {
-		dsl_pool_t *dp = ds->ds_dir->dd_pool;
-
-		if (fromsnap)
-			return (EINVAL);
-
-		if (dsl_dir_is_clone(ds->ds_dir)) {
-			rw_enter(&dp->dp_config_rwlock, RW_READER);
-			err = dsl_dataset_hold_obj(dp,
-			    ds->ds_dir->dd_phys->dd_origin_obj, FTAG, &fromds);
-			rw_exit(&dp->dp_config_rwlock);
-			if (err)
-				return (err);
-		} else {
-			fromorigin = B_FALSE;
-		}
-	}
-
-
 	drr = kmem_zalloc(sizeof (dmu_replay_record_t), KM_SLEEP);
 	drr->drr_type = DRR_BEGIN;
 	drr->drr_u.drr_begin.drr_magic = DMU_BACKUP_MAGIC;
@@ -479,7 +501,7 @@ dmu_send(objset_t *tosnap, objset_t *fromsnap, boolean_t fromorigin,
 	drr->drr_u.drr_begin.drr_creation_time =
 	    ds->ds_phys->ds_creation_time;
 	drr->drr_u.drr_begin.drr_type = tosnap->os_phys->os_type;
-	if (fromorigin)
+	if (fromds != NULL && ds->ds_dir != fromds->ds_dir)
 		drr->drr_u.drr_begin.drr_flags |= DRR_FLAG_CLONE;
 	drr->drr_u.drr_begin.drr_toguid = ds->ds_phys->ds_guid;
 	if (ds->ds_phys->ds_flags & DS_FLAG_CI_DATASET)
@@ -491,8 +513,6 @@ dmu_send(objset_t *tosnap, objset_t *fromsnap, boolean_t fromorigin,
 
 	if (fromds)
 		fromtxg = fromds->ds_phys->ds_creation_txg;
-	if (fromorigin)
-		dsl_dataset_rele(fromds, FTAG);
 
 	dsp = kmem_zalloc(sizeof (dmu_sendarg_t), KM_SLEEP);
 
@@ -550,8 +570,7 @@ out:
 }
 
 int
-dmu_send_estimate(objset_t *tosnap, objset_t *fromsnap, boolean_t fromorigin,
-    uint64_t *sizep)
+dmu_send_estimate(objset_t *tosnap, objset_t *fromsnap, uint64_t *sizep)
 {
 	dsl_dataset_t *ds = tosnap->os_dsl_dataset;
 	dsl_dataset_t *fromds = fromsnap ? fromsnap->os_dsl_dataset : NULL;
@@ -563,27 +582,13 @@ dmu_send_estimate(objset_t *tosnap, objset_t *fromsnap, boolean_t fromorigin,
 	if (ds->ds_phys->ds_next_snap_obj == 0)
 		return (EINVAL);
 
-	/* fromsnap must be an earlier snapshot from the same fs as tosnap */
-	if (fromds && (ds->ds_dir != fromds->ds_dir ||
-	    fromds->ds_phys->ds_creation_txg >= ds->ds_phys->ds_creation_txg))
+	/*
+	 * fromsnap must be an earlier snapshot from the same fs as tosnap,
+	 * or the origin's fs.
+	 */
+	if (fromds != NULL && !is_before(ds, fromds))
 		return (EXDEV);
 
-	if (fromorigin) {
-		if (fromsnap)
-			return (EINVAL);
-
-		if (dsl_dir_is_clone(ds->ds_dir)) {
-			rw_enter(&dp->dp_config_rwlock, RW_READER);
-			err = dsl_dataset_hold_obj(dp,
-			    ds->ds_dir->dd_phys->dd_origin_obj, FTAG, &fromds);
-			rw_exit(&dp->dp_config_rwlock);
-			if (err)
-				return (err);
-		} else {
-			fromorigin = B_FALSE;
-		}
-	}
-
 	/* Get uncompressed size estimate of changed data. */
 	if (fromds == NULL) {
 		size = ds->ds_phys->ds_uncompressed_bytes;
@@ -591,8 +596,6 @@ dmu_send_estimate(objset_t *tosnap, objset_t *fromsnap, boolean_t fromorigin,
 		uint64_t used, comp;
 		err = dsl_dataset_space_written(fromds, ds,
 		    &used, &comp, &size);
-		if (fromorigin)
-			dsl_dataset_rele(fromds, FTAG);
 		if (err)
 			return (err);
 	}
@@ -690,8 +693,7 @@ recv_new_sync(void *arg1, void *arg2, dmu_tx_t *tx)
 		    rbsa->ds, &rbsa->ds->ds_phys->ds_bp, rbsa->type, tx);
 	}
 
-	spa_history_log_internal(LOG_DS_REPLAY_FULL_SYNC,
-	    dd->dd_pool->dp_spa, tx, "dataset = %lld", dsobj);
+	spa_history_log_internal_ds(rbsa->ds, "receive new", tx, "");
 }
 
 /* ARGSUSED */
@@ -792,8 +794,7 @@ recv_existing_sync(void *arg1, void *arg2, dmu_tx_t *tx)
 
 	rbsa->ds = cds;
 
-	spa_history_log_internal(LOG_DS_REPLAY_INC_SYNC,
-	    dp->dp_spa, tx, "dataset = %lld", dsobj);
+	spa_history_log_internal_ds(cds, "receive over existing", tx, "");
 }
 
 static boolean_t
@@ -1604,6 +1605,7 @@ recv_end_sync(void *arg1, void *arg2, dmu_tx_t *tx)
 
 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
 	ds->ds_phys->ds_flags &= ~DS_FLAG_INCONSISTENT;
+	spa_history_log_internal_ds(ds, "finished receiving", tx, "");
 }
 
 static int