OpenZFS 2605, 6980, 6902

2605 want to resume interrupted zfs send
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: Richard Elling <Richard.Elling@RichardElling.com>
Reviewed by: Xin Li <delphij@freebsd.org>
Reviewed by: Arne Jansen <sensille@gmx.net>
Approved by: Dan McDonald <danmcd@omniti.com>
Ported-by: kernelOfTruth <kerneloftruth@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>

OpenZFS-issue: https://www.illumos.org/issues/2605
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/9c3fd12

6980 6902 causes zfs send to break due to 32-bit/64-bit struct mismatch
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Approved by: Robert Mustacchi <rm@joyent.com>
Ported by: Brian Behlendorf <behlendorf1@llnl.gov>

OpenZFS-issue: https://www.illumos.org/issues/6980
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/ea4a67f

Porting notes:
- All rsend and snapshop tests enabled and updated for Linux.
- Fix misuse of input argument in traverse_visitbp().
- Fix ISO C90 warnings and errors.
- Fix gcc 'missing braces around initializer' in
  'struct send_thread_arg to_arg =' warning.
- Replace 4 argument fletcher_4_native() with 3 argument version,
  this change was made in OpenZFS 4185 which has not been ported.
- Part of the sections for 'zfs receive' and 'zfs send' was
  rewritten and reordered to approximate upstream.
- Fix mktree xattr creation, 'user.' prefix required.
- Minor fixes to newly enabled test cases
- Long holds for volumes allowed during receive for minor registration.

module/zfs/zfs_ioctl.c

@@ -4005,6 +4005,7 @@ static boolean_t zfs_ioc_recv_inject_err;
  * zc_guid		force flag
  * zc_cleanup_fd	cleanup-on-exit file descriptor
  * zc_action_handle	handle for this guid/ds mapping (or zero on first call)
+ * zc_resumable		if data is incomplete assume sender will resume
  *
  * outputs:
  * zc_cookie		number of bytes read
@@ -4051,13 +4052,13 @@ zfs_ioc_recv(zfs_cmd_t *zc)
 		return (SET_ERROR(EBADF));
 	}
 
-	VERIFY(nvlist_alloc(&errors, NV_UNIQUE_NAME, KM_SLEEP) == 0);
+	errors = fnvlist_alloc();
 
 	if (zc->zc_string[0])
 		origin = zc->zc_string;
 
 	error = dmu_recv_begin(tofs, tosnap,
-	    &zc->zc_begin_record, force, origin, &drc);
+	    &zc->zc_begin_record, force, zc->zc_resumable, origin, &drc);
 	if (error != 0)
 		goto out;
 
@@ -5182,6 +5183,8 @@ zfs_ioc_space_snaps(const char *lastsnap, nvlist_t *innvl, nvlist_t *outnvl)
  *         indicates that blocks > 128KB are permitted
  *     (optional) "embedok" -> (value ignored)
  *         presence indicates DRR_WRITE_EMBEDDED records are permitted
+ *     (optional) "resume_object" and "resume_offset" -> (uint64)
+ *         if present, resume send stream from specified object and offset.
  * }
  *
  * outnvl is unused
@@ -5197,6 +5200,8 @@ zfs_ioc_send_new(const char *snapname, nvlist_t *innvl, nvlist_t *outnvl)
 	file_t *fp;
 	boolean_t largeblockok;
 	boolean_t embedok;
+	uint64_t resumeobj = 0;
+	uint64_t resumeoff = 0;
 
 	error = nvlist_lookup_int32(innvl, "fd", &fd);
 	if (error != 0)
@@ -5207,12 +5212,15 @@ zfs_ioc_send_new(const char *snapname, nvlist_t *innvl, nvlist_t *outnvl)
 	largeblockok = nvlist_exists(innvl, "largeblockok");
 	embedok = nvlist_exists(innvl, "embedok");
 
+	(void) nvlist_lookup_uint64(innvl, "resume_object", &resumeobj);
+	(void) nvlist_lookup_uint64(innvl, "resume_offset", &resumeoff);
+
 	if ((fp = getf(fd)) == NULL)
 		return (SET_ERROR(EBADF));
 
 	off = fp->f_offset;
-	error = dmu_send(snapname, fromname, embedok, largeblockok,
-	    fd, fp->f_vnode, &off);
+	error = dmu_send(snapname, fromname, embedok, largeblockok, fd,
+	    resumeobj, resumeoff, fp->f_vnode, &off);
 
 	if (VOP_SEEK(fp->f_vnode, fp->f_offset, &off, NULL) == 0)
 		fp->f_offset = off;