--- a/usr/src/uts/common/fs/zfs/dmu_send.c	Tue May 08 05:52:36 2012 -0500
+++ b/usr/src/uts/common/fs/zfs/dmu_send.c	Wed May 09 15:05:14 2012 -0700
@@ -25,6 +25,7 @@
 /*
  * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
  * Copyright (c) 2011 by Delphix. All rights reserved.
+ * Copyright (c) 2012, Joyent, Inc. All rights reserved.
  */
 
 #include <sys/dmu.h>
@@ -54,48 +55,30 @@
 
 static char *dmu_recv_tag = "dmu_recv_tag";
 
-/*
- * The list of data whose inclusion in a send stream can be pending from
- * one call to backup_cb to another.  Multiple calls to dump_free() and
- * dump_freeobjects() can be aggregated into a single DRR_FREE or
- * DRR_FREEOBJECTS replay record.
- */
-typedef enum {
-	PENDING_NONE,
-	PENDING_FREE,
-	PENDING_FREEOBJECTS
-} pendop_t;
-
-struct backuparg {
-	dmu_replay_record_t *drr;
-	vnode_t *vp;
-	offset_t *off;
-	objset_t *os;
-	zio_cksum_t zc;
-	uint64_t toguid;
-	int err;
-	pendop_t pending_op;
-};
-
 static int
-dump_bytes(struct backuparg *ba, void *buf, int len)
+dump_bytes(dmu_sendarg_t *dsp, void *buf, int len)
 {
+	dsl_dataset_t *ds = dsp->dsa_os->os_dsl_dataset;
 	ssize_t resid; /* have to get resid to get detailed errno */
 	ASSERT3U(len % 8, ==, 0);
 
-	fletcher_4_incremental_native(buf, len, &ba->zc);
-	ba->err = vn_rdwr(UIO_WRITE, ba->vp,
+	fletcher_4_incremental_native(buf, len, &dsp->dsa_zc);
+	dsp->dsa_err = vn_rdwr(UIO_WRITE, dsp->dsa_vp,
 	    (caddr_t)buf, len,
 	    0, UIO_SYSSPACE, FAPPEND, RLIM64_INFINITY, CRED(), &resid);
-	*ba->off += len;
-	return (ba->err);
+
+	mutex_enter(&ds->ds_sendstream_lock);
+	*dsp->dsa_off += len;
+	mutex_exit(&ds->ds_sendstream_lock);
+
+	return (dsp->dsa_err);
 }
 
 static int
-dump_free(struct backuparg *ba, uint64_t object, uint64_t offset,
+dump_free(dmu_sendarg_t *dsp, uint64_t object, uint64_t offset,
     uint64_t length)
 {
-	struct drr_free *drrf = &(ba->drr->drr_u.drr_free);
+	struct drr_free *drrf = &(dsp->dsa_drr->drr_u.drr_free);
 
 	/*
 	 * If there is a pending op, but it's not PENDING_FREE, push it out,
@@ -104,13 +87,15 @@
 	 * other DRR_FREE records.  DRR_FREEOBJECTS records can only be
 	 * aggregated with other DRR_FREEOBJECTS records.
 	 */
-	if (ba->pending_op != PENDING_NONE && ba->pending_op != PENDING_FREE) {
-		if (dump_bytes(ba, ba->drr, sizeof (dmu_replay_record_t)) != 0)
+	if (dsp->dsa_pending_op != PENDING_NONE &&
+	    dsp->dsa_pending_op != PENDING_FREE) {
+		if (dump_bytes(dsp, dsp->dsa_drr,
+		    sizeof (dmu_replay_record_t)) != 0)
 			return (EINTR);
-		ba->pending_op = PENDING_NONE;
+		dsp->dsa_pending_op = PENDING_NONE;
 	}
 
-	if (ba->pending_op == PENDING_FREE) {
+	if (dsp->dsa_pending_op == PENDING_FREE) {
 		/*
 		 * There should never be a PENDING_FREE if length is -1
 		 * (because dump_dnode is the only place where this
@@ -128,34 +113,35 @@
 			return (0);
 		} else {
 			/* not a continuation.  Push out pending record */
-			if (dump_bytes(ba, ba->drr,
+			if (dump_bytes(dsp, dsp->dsa_drr,
 			    sizeof (dmu_replay_record_t)) != 0)
 				return (EINTR);
-			ba->pending_op = PENDING_NONE;
+			dsp->dsa_pending_op = PENDING_NONE;
 		}
 	}
 	/* create a FREE record and make it pending */
-	bzero(ba->drr, sizeof (dmu_replay_record_t));
-	ba->drr->drr_type = DRR_FREE;
+	bzero(dsp->dsa_drr, sizeof (dmu_replay_record_t));
+	dsp->dsa_drr->drr_type = DRR_FREE;
 	drrf->drr_object = object;
 	drrf->drr_offset = offset;
 	drrf->drr_length = length;
-	drrf->drr_toguid = ba->toguid;
+	drrf->drr_toguid = dsp->dsa_toguid;
 	if (length == -1ULL) {
-		if (dump_bytes(ba, ba->drr, sizeof (dmu_replay_record_t)) != 0)
+		if (dump_bytes(dsp, dsp->dsa_drr,
+		    sizeof (dmu_replay_record_t)) != 0)
 			return (EINTR);
 	} else {
-		ba->pending_op = PENDING_FREE;
+		dsp->dsa_pending_op = PENDING_FREE;
 	}
 
 	return (0);
 }
 
 static int
-dump_data(struct backuparg *ba, dmu_object_type_t type,
+dump_data(dmu_sendarg_t *dsp, dmu_object_type_t type,
     uint64_t object, uint64_t offset, int blksz, const blkptr_t *bp, void *data)
 {
-	struct drr_write *drrw = &(ba->drr->drr_u.drr_write);
+	struct drr_write *drrw = &(dsp->dsa_drr->drr_u.drr_write);
 
 
 	/*
@@ -164,19 +150,20 @@
 	 * the stream, since aggregation can't be done across operations
 	 * of different types.
 	 */
-	if (ba->pending_op != PENDING_NONE) {
-		if (dump_bytes(ba, ba->drr, sizeof (dmu_replay_record_t)) != 0)
+	if (dsp->dsa_pending_op != PENDING_NONE) {
+		if (dump_bytes(dsp, dsp->dsa_drr,
+		    sizeof (dmu_replay_record_t)) != 0)
 			return (EINTR);
-		ba->pending_op = PENDING_NONE;
+		dsp->dsa_pending_op = PENDING_NONE;
 	}
 	/* write a DATA record */
-	bzero(ba->drr, sizeof (dmu_replay_record_t));
-	ba->drr->drr_type = DRR_WRITE;
+	bzero(dsp->dsa_drr, sizeof (dmu_replay_record_t));
+	dsp->dsa_drr->drr_type = DRR_WRITE;
 	drrw->drr_object = object;
 	drrw->drr_type = type;
 	drrw->drr_offset = offset;
 	drrw->drr_length = blksz;
-	drrw->drr_toguid = ba->toguid;
+	drrw->drr_toguid = dsp->dsa_toguid;
 	drrw->drr_checksumtype = BP_GET_CHECKSUM(bp);
 	if (zio_checksum_table[drrw->drr_checksumtype].ci_dedup)
 		drrw->drr_checksumflags |= DRR_CHECKSUM_DEDUP;
@@ -185,42 +172,43 @@
 	DDK_SET_COMPRESS(&drrw->drr_key, BP_GET_COMPRESS(bp));
 	drrw->drr_key.ddk_cksum = bp->blk_cksum;
 
-	if (dump_bytes(ba, ba->drr, sizeof (dmu_replay_record_t)) != 0)
+	if (dump_bytes(dsp, dsp->dsa_drr, sizeof (dmu_replay_record_t)) != 0)
 		return (EINTR);
-	if (dump_bytes(ba, data, blksz) != 0)
+	if (dump_bytes(dsp, data, blksz) != 0)
 		return (EINTR);
 	return (0);
 }
 
 static int
-dump_spill(struct backuparg *ba, uint64_t object, int blksz, void *data)
+dump_spill(dmu_sendarg_t *dsp, uint64_t object, int blksz, void *data)
 {
-	struct drr_spill *drrs = &(ba->drr->drr_u.drr_spill);
+	struct drr_spill *drrs = &(dsp->dsa_drr->drr_u.drr_spill);
 
-	if (ba->pending_op != PENDING_NONE) {
-		if (dump_bytes(ba, ba->drr, sizeof (dmu_replay_record_t)) != 0)
+	if (dsp->dsa_pending_op != PENDING_NONE) {
+		if (dump_bytes(dsp, dsp->dsa_drr,
+		    sizeof (dmu_replay_record_t)) != 0)
 			return (EINTR);
-		ba->pending_op = PENDING_NONE;
+		dsp->dsa_pending_op = PENDING_NONE;
 	}
 
 	/* write a SPILL record */
-	bzero(ba->drr, sizeof (dmu_replay_record_t));
-	ba->drr->drr_type = DRR_SPILL;
+	bzero(dsp->dsa_drr, sizeof (dmu_replay_record_t));
+	dsp->dsa_drr->drr_type = DRR_SPILL;
 	drrs->drr_object = object;
 	drrs->drr_length = blksz;
-	drrs->drr_toguid = ba->toguid;
+	drrs->drr_toguid = dsp->dsa_toguid;
 
-	if (dump_bytes(ba, ba->drr, sizeof (dmu_replay_record_t)))
+	if (dump_bytes(dsp, dsp->dsa_drr, sizeof (dmu_replay_record_t)))
 		return (EINTR);
-	if (dump_bytes(ba, data, blksz))
+	if (dump_bytes(dsp, data, blksz))
 		return (EINTR);
 	return (0);
 }
 
 static int
-dump_freeobjects(struct backuparg *ba, uint64_t firstobj, uint64_t numobjs)
+dump_freeobjects(dmu_sendarg_t *dsp, uint64_t firstobj, uint64_t numobjs)
 {
-	struct drr_freeobjects *drrfo = &(ba->drr->drr_u.drr_freeobjects);
+	struct drr_freeobjects *drrfo = &(dsp->dsa_drr->drr_u.drr_freeobjects);
 
 	/*
 	 * If there is a pending op, but it's not PENDING_FREEOBJECTS,
@@ -229,13 +217,14 @@
 	 * aggregated with other DRR_FREE records.  DRR_FREEOBJECTS records
 	 * can only be aggregated with other DRR_FREEOBJECTS records.
 	 */
-	if (ba->pending_op != PENDING_NONE &&
-	    ba->pending_op != PENDING_FREEOBJECTS) {
-		if (dump_bytes(ba, ba->drr, sizeof (dmu_replay_record_t)) != 0)
+	if (dsp->dsa_pending_op != PENDING_NONE &&
+	    dsp->dsa_pending_op != PENDING_FREEOBJECTS) {
+		if (dump_bytes(dsp, dsp->dsa_drr,
+		    sizeof (dmu_replay_record_t)) != 0)
 			return (EINTR);
-		ba->pending_op = PENDING_NONE;
+		dsp->dsa_pending_op = PENDING_NONE;
 	}
-	if (ba->pending_op == PENDING_FREEOBJECTS) {
+	if (dsp->dsa_pending_op == PENDING_FREEOBJECTS) {
 		/*
 		 * See whether this free object array can be aggregated
 		 * with pending one
@@ -245,42 +234,43 @@
 			return (0);
 		} else {
 			/* can't be aggregated.  Push out pending record */
-			if (dump_bytes(ba, ba->drr,
+			if (dump_bytes(dsp, dsp->dsa_drr,
 			    sizeof (dmu_replay_record_t)) != 0)
 				return (EINTR);
-			ba->pending_op = PENDING_NONE;
+			dsp->dsa_pending_op = PENDING_NONE;
 		}
 	}
 
 	/* write a FREEOBJECTS record */
-	bzero(ba->drr, sizeof (dmu_replay_record_t));
-	ba->drr->drr_type = DRR_FREEOBJECTS;
+	bzero(dsp->dsa_drr, sizeof (dmu_replay_record_t));
+	dsp->dsa_drr->drr_type = DRR_FREEOBJECTS;
 	drrfo->drr_firstobj = firstobj;
 	drrfo->drr_numobjs = numobjs;
-	drrfo->drr_toguid = ba->toguid;
+	drrfo->drr_toguid = dsp->dsa_toguid;
 
-	ba->pending_op = PENDING_FREEOBJECTS;
+	dsp->dsa_pending_op = PENDING_FREEOBJECTS;
 
 	return (0);
 }
 
 static int
-dump_dnode(struct backuparg *ba, uint64_t object, dnode_phys_t *dnp)
+dump_dnode(dmu_sendarg_t *dsp, uint64_t object, dnode_phys_t *dnp)
 {
-	struct drr_object *drro = &(ba->drr->drr_u.drr_object);
+	struct drr_object *drro = &(dsp->dsa_drr->drr_u.drr_object);
 
 	if (dnp == NULL || dnp->dn_type == DMU_OT_NONE)
-		return (dump_freeobjects(ba, object, 1));
+		return (dump_freeobjects(dsp, object, 1));
 
-	if (ba->pending_op != PENDING_NONE) {
-		if (dump_bytes(ba, ba->drr, sizeof (dmu_replay_record_t)) != 0)
+	if (dsp->dsa_pending_op != PENDING_NONE) {
+		if (dump_bytes(dsp, dsp->dsa_drr,
+		    sizeof (dmu_replay_record_t)) != 0)
 			return (EINTR);
-		ba->pending_op = PENDING_NONE;
+		dsp->dsa_pending_op = PENDING_NONE;
 	}
 
 	/* write an OBJECT record */
-	bzero(ba->drr, sizeof (dmu_replay_record_t));
-	ba->drr->drr_type = DRR_OBJECT;
+	bzero(dsp->dsa_drr, sizeof (dmu_replay_record_t));
+	dsp->dsa_drr->drr_type = DRR_OBJECT;
 	drro->drr_object = object;
 	drro->drr_type = dnp->dn_type;
 	drro->drr_bonustype = dnp->dn_bonustype;
@@ -288,19 +278,19 @@
 	drro->drr_bonuslen = dnp->dn_bonuslen;
 	drro->drr_checksumtype = dnp->dn_checksum;
 	drro->drr_compress = dnp->dn_compress;
-	drro->drr_toguid = ba->toguid;
+	drro->drr_toguid = dsp->dsa_toguid;
 
-	if (dump_bytes(ba, ba->drr, sizeof (dmu_replay_record_t)) != 0)
+	if (dump_bytes(dsp, dsp->dsa_drr, sizeof (dmu_replay_record_t)) != 0)
 		return (EINTR);
 
-	if (dump_bytes(ba, DN_BONUS(dnp), P2ROUNDUP(dnp->dn_bonuslen, 8)) != 0)
+	if (dump_bytes(dsp, DN_BONUS(dnp), P2ROUNDUP(dnp->dn_bonuslen, 8)) != 0)
 		return (EINTR);
 
 	/* free anything past the end of the file */
-	if (dump_free(ba, object, (dnp->dn_maxblkid + 1) *
+	if (dump_free(dsp, object, (dnp->dn_maxblkid + 1) *
 	    (dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT), -1ULL))
 		return (EINTR);
-	if (ba->err)
+	if (dsp->dsa_err)
 		return (EINTR);
 	return (0);
 }
@@ -314,7 +304,7 @@
 backup_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp, arc_buf_t *pbuf,
     const zbookmark_t *zb, const dnode_phys_t *dnp, void *arg)
 {
-	struct backuparg *ba = arg;
+	dmu_sendarg_t *dsp = arg;
 	dmu_object_type_t type = bp ? BP_GET_TYPE(bp) : DMU_OT_NONE;
 	int err = 0;
 
@@ -327,10 +317,10 @@
 	} else if (bp == NULL && zb->zb_object == DMU_META_DNODE_OBJECT) {
 		uint64_t span = BP_SPAN(dnp, zb->zb_level);
 		uint64_t dnobj = (zb->zb_blkid * span) >> DNODE_SHIFT;
-		err = dump_freeobjects(ba, dnobj, span >> DNODE_SHIFT);
+		err = dump_freeobjects(dsp, dnobj, span >> DNODE_SHIFT);
 	} else if (bp == NULL) {
 		uint64_t span = BP_SPAN(dnp, zb->zb_level);
-		err = dump_free(ba, zb->zb_object, zb->zb_blkid * span, span);
+		err = dump_free(dsp, zb->zb_object, zb->zb_blkid * span, span);
 	} else if (zb->zb_level > 0 || type == DMU_OT_OBJSET) {
 		return (0);
 	} else if (type == DMU_OT_DNODE) {
@@ -349,7 +339,7 @@
 		for (i = 0; i < blksz >> DNODE_SHIFT; i++) {
 			uint64_t dnobj = (zb->zb_blkid <<
 			    (DNODE_BLOCK_SHIFT - DNODE_SHIFT)) + i;
-			err = dump_dnode(ba, dnobj, blk+i);
+			err = dump_dnode(dsp, dnobj, blk+i);
 			if (err)
 				break;
 		}
@@ -364,7 +354,7 @@
 		    ZIO_FLAG_CANFAIL, &aflags, zb) != 0)
 			return (EIO);
 
-		err = dump_spill(ba, zb->zb_object, blksz, abuf->b_data);
+		err = dump_spill(dsp, zb->zb_object, blksz, abuf->b_data);
 		(void) arc_buf_remove_ref(abuf, &abuf);
 	} else { /* it's a level-0 block of a regular object */
 		uint32_t aflags = ARC_WAIT;
@@ -388,7 +378,7 @@
 			}
 		}
 
-		err = dump_data(ba, type, zb->zb_object, zb->zb_blkid * blksz,
+		err = dump_data(dsp, type, zb->zb_object, zb->zb_blkid * blksz,
 		    blksz, bp, abuf->b_data);
 		(void) arc_buf_remove_ref(abuf, &abuf);
 	}
@@ -398,13 +388,13 @@
 }
 
 int
-dmu_sendbackup(objset_t *tosnap, objset_t *fromsnap, boolean_t fromorigin,
-    vnode_t *vp, offset_t *off)
+dmu_send(objset_t *tosnap, objset_t *fromsnap, boolean_t fromorigin,
+    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;
 	dmu_replay_record_t *drr;
-	struct backuparg ba;
+	dmu_sendarg_t *dsp;
 	int err;
 	uint64_t fromtxg = 0;
 
@@ -445,8 +435,10 @@
 #ifdef _KERNEL
 	if (dmu_objset_type(tosnap) == DMU_OST_ZFS) {
 		uint64_t version;
-		if (zfs_get_zplprop(tosnap, ZFS_PROP_VERSION, &version) != 0)
+		if (zfs_get_zplprop(tosnap, ZFS_PROP_VERSION, &version) != 0) {
+			kmem_free(drr, sizeof (dmu_replay_record_t));
 			return (EINVAL);
+		}
 		if (version == ZPL_VERSION_SA) {
 			DMU_SET_FEATUREFLAGS(
 			    drr->drr_u.drr_begin.drr_versioninfo,
@@ -473,46 +465,59 @@
 	if (fromorigin)
 		dsl_dataset_rele(fromds, FTAG);
 
-	ba.drr = drr;
-	ba.vp = vp;
-	ba.os = tosnap;
-	ba.off = off;
-	ba.toguid = ds->ds_phys->ds_guid;
-	ZIO_SET_CHECKSUM(&ba.zc, 0, 0, 0, 0);
-	ba.pending_op = PENDING_NONE;
+	dsp = kmem_zalloc(sizeof (dmu_sendarg_t), KM_SLEEP);
 
-	if (dump_bytes(&ba, drr, sizeof (dmu_replay_record_t)) != 0) {
-		kmem_free(drr, sizeof (dmu_replay_record_t));
-		return (ba.err);
+	dsp->dsa_drr = drr;
+	dsp->dsa_vp = vp;
+	dsp->dsa_outfd = outfd;
+	dsp->dsa_proc = curproc;
+	dsp->dsa_os = tosnap;
+	dsp->dsa_off = off;
+	dsp->dsa_toguid = ds->ds_phys->ds_guid;
+	ZIO_SET_CHECKSUM(&dsp->dsa_zc, 0, 0, 0, 0);
+	dsp->dsa_pending_op = PENDING_NONE;
+
+	mutex_enter(&ds->ds_sendstream_lock);
+	list_insert_head(&ds->ds_sendstreams, dsp);
+	mutex_exit(&ds->ds_sendstream_lock);
+
+	if (dump_bytes(dsp, drr, sizeof (dmu_replay_record_t)) != 0) {
+		err = dsp->dsa_err;
+		goto out;
 	}
 
 	err = traverse_dataset(ds, fromtxg, TRAVERSE_PRE | TRAVERSE_PREFETCH,
-	    backup_cb, &ba);
+	    backup_cb, dsp);
 
-	if (ba.pending_op != PENDING_NONE)
-		if (dump_bytes(&ba, drr, sizeof (dmu_replay_record_t)) != 0)
+	if (dsp->dsa_pending_op != PENDING_NONE)
+		if (dump_bytes(dsp, drr, sizeof (dmu_replay_record_t)) != 0)
 			err = EINTR;
 
 	if (err) {
-		if (err == EINTR && ba.err)
-			err = ba.err;
-		kmem_free(drr, sizeof (dmu_replay_record_t));
-		return (err);
+		if (err == EINTR && dsp->dsa_err)
+			err = dsp->dsa_err;
+		goto out;
 	}
 
 	bzero(drr, sizeof (dmu_replay_record_t));
 	drr->drr_type = DRR_END;
-	drr->drr_u.drr_end.drr_checksum = ba.zc;
-	drr->drr_u.drr_end.drr_toguid = ba.toguid;
+	drr->drr_u.drr_end.drr_checksum = dsp->dsa_zc;
+	drr->drr_u.drr_end.drr_toguid = dsp->dsa_toguid;
 
-	if (dump_bytes(&ba, drr, sizeof (dmu_replay_record_t)) != 0) {
-		kmem_free(drr, sizeof (dmu_replay_record_t));
-		return (ba.err);
+	if (dump_bytes(dsp, drr, sizeof (dmu_replay_record_t)) != 0) {
+		err = dsp->dsa_err;
+		goto out;
 	}
 
-	kmem_free(drr, sizeof (dmu_replay_record_t));
+out:
+	mutex_enter(&ds->ds_sendstream_lock);
+	list_remove(&ds->ds_sendstreams, dsp);
+	mutex_exit(&ds->ds_sendstream_lock);
 
-	return (0);
+	kmem_free(drr, sizeof (dmu_replay_record_t));
+	kmem_free(dsp, sizeof (dmu_sendarg_t));
+
+	return (err);
 }
 
 int