Add 'zfs send --saved' flag

This commit adds the --saved (-S) to the 'zfs send' command.
This flag allows a user to send a partially received dataset,
which can be useful when migrating a backup server to new
hardware. This flag is compatible with resumable receives, so
even if the saved send is interrupted, it can be resumed.
The flag does not require any user / kernel ABI changes or any
new feature flags in the send stream format.

Reviewed-by: Paul Dagnelie <[email protected]>
Reviewed-by: Alek Pinchuk <[email protected]>
Reviewed-by: Paul Zuchowski <[email protected]>
Reviewed-by: Christian Schwarz <[email protected]>
Reviewed-by: Matt Ahrens <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Tom Caputi <[email protected]>
Closes #9007 

1 files changed, 17 insertions, 8 deletions

diff --git a/module/zfs/zfs_ioctl.c b/module/zfs/zfs_ioctl.c
index 2c1f0aab6..fb8034f70 100644
--- a/module/zfs/zfs_ioctl.c
+++ b/module/zfs/zfs_ioctl.c
@@ -5291,6 +5291,7 @@ zfs_ioc_send(zfs_cmd_t *zc)
 	boolean_t large_block_ok = (zc->zc_flags & 0x2);
 	boolean_t compressok = (zc->zc_flags & 0x4);
 	boolean_t rawok = (zc->zc_flags & 0x8);
+	boolean_t savedok = (zc->zc_flags & 0x10);
 
 	if (zc->zc_obj != 0) {
 		dsl_pool_t *dp;
@@ -5340,7 +5341,7 @@ zfs_ioc_send(zfs_cmd_t *zc)
 		}
 
 		error = dmu_send_estimate_fast(tosnap, fromsnap, NULL,
-		    compressok || rawok, &zc->zc_objset_type);
+		    compressok || rawok, savedok, &zc->zc_objset_type);
 
 		if (fromsnap != NULL)
 			dsl_dataset_rele(fromsnap, FTAG);
@@ -5358,8 +5359,8 @@ zfs_ioc_send(zfs_cmd_t *zc)
 		out.dso_arg = fp;
 		out.dso_dryrun = B_FALSE;
 		error = dmu_send_obj(zc->zc_name, zc->zc_sendobj,
-		    zc->zc_fromobj, embedok, large_block_ok, compressok, rawok,
-		    zc->zc_cookie, &off, &out);
+		    zc->zc_fromobj, embedok, large_block_ok, compressok,
+		    rawok, savedok, zc->zc_cookie, &off, &out);
 
 		zfs_file_put(zc->zc_cookie);
 	}
@@ -6245,6 +6246,8 @@ zfs_ioc_space_snaps(const char *lastsnap, nvlist_t *innvl, nvlist_t *outnvl)
  *         presence indicates compressed DRR_WRITE records are permitted
  *     (optional) "rawok" -> (value ignored)
  *         presence indicates raw encrypted records should be used.
+ *     (optional) "savedok" -> (value ignored)
+ *         presence indicates we should send a partially received snapshot
  *     (optional) "resume_object" and "resume_offset" -> (uint64)
  *         if present, resume send stream from specified object and offset.
  *     (optional) "redactbook" -> (string)
@@ -6261,6 +6264,7 @@ static const zfs_ioc_key_t zfs_keys_send_new[] = {
 	{"embedok",		DATA_TYPE_BOOLEAN,	ZK_OPTIONAL},
 	{"compressok",		DATA_TYPE_BOOLEAN,	ZK_OPTIONAL},
 	{"rawok",		DATA_TYPE_BOOLEAN,	ZK_OPTIONAL},
+	{"savedok",		DATA_TYPE_BOOLEAN,	ZK_OPTIONAL},
 	{"resume_object",	DATA_TYPE_UINT64,	ZK_OPTIONAL},
 	{"resume_offset",	DATA_TYPE_UINT64,	ZK_OPTIONAL},
 	{"redactbook",		DATA_TYPE_STRING,	ZK_OPTIONAL},
@@ -6279,6 +6283,7 @@ zfs_ioc_send_new(const char *snapname, nvlist_t *innvl, nvlist_t *outnvl)
 	boolean_t embedok;
 	boolean_t compressok;
 	boolean_t rawok;
+	boolean_t savedok;
 	uint64_t resumeobj = 0;
 	uint64_t resumeoff = 0;
 	char *redactbook = NULL;
@@ -6291,6 +6296,7 @@ zfs_ioc_send_new(const char *snapname, nvlist_t *innvl, nvlist_t *outnvl)
 	embedok = nvlist_exists(innvl, "embedok");
 	compressok = nvlist_exists(innvl, "compressok");
 	rawok = nvlist_exists(innvl, "rawok");
+	savedok = nvlist_exists(innvl, "savedok");
 
 	(void) nvlist_lookup_uint64(innvl, "resume_object", &resumeobj);
 	(void) nvlist_lookup_uint64(innvl, "resume_offset", &resumeoff);
@@ -6306,8 +6312,9 @@ zfs_ioc_send_new(const char *snapname, nvlist_t *innvl, nvlist_t *outnvl)
 	out.dso_outfunc = dump_bytes;
 	out.dso_arg = fp;
 	out.dso_dryrun = B_FALSE;
-	error = dmu_send(snapname, fromname, embedok, largeblockok, compressok,
-	    rawok, resumeobj, resumeoff, redactbook, fd, &off, &out);
+	error = dmu_send(snapname, fromname, embedok, largeblockok,
+	    compressok, rawok, savedok, resumeobj, resumeoff,
+	    redactbook, fd, &off, &out);
 
 	zfs_file_put(fd);
 	return (error);
@@ -6372,6 +6379,7 @@ zfs_ioc_send_space(const char *snapname, nvlist_t *innvl, nvlist_t *outnvl)
 	boolean_t embedok;
 	boolean_t compressok;
 	boolean_t rawok;
+	boolean_t savedok;
 	uint64_t space = 0;
 	boolean_t full_estimate = B_FALSE;
 	uint64_t resumeobj = 0;
@@ -6395,6 +6403,7 @@ zfs_ioc_send_space(const char *snapname, nvlist_t *innvl, nvlist_t *outnvl)
 	embedok = nvlist_exists(innvl, "embedok");
 	compressok = nvlist_exists(innvl, "compressok");
 	rawok = nvlist_exists(innvl, "rawok");
+	savedok = nvlist_exists(innvl, "savedok");
 	boolean_t from = (nvlist_lookup_string(innvl, "from", &fromname) == 0);
 	boolean_t altbook = (nvlist_lookup_string(innvl, "redactbook",
 	    &redactlist_book) == 0);
@@ -6469,12 +6478,12 @@ zfs_ioc_send_space(const char *snapname, nvlist_t *innvl, nvlist_t *outnvl)
 		dsl_dataset_rele(tosnap, FTAG);
 		dsl_pool_rele(dp, FTAG);
 		error = dmu_send(snapname, fromname, embedok, largeblockok,
-		    compressok, rawok, resumeobj, resumeoff, redactlist_book,
-		    fd, &off, &out);
+		    compressok, rawok, savedok, resumeobj, resumeoff,
+		    redactlist_book, fd, &off, &out);
 	} else {
 		error = dmu_send_estimate_fast(tosnap, fromsnap,
 		    (from && strchr(fromname, '#') != NULL ? &zbm : NULL),
-		    compressok || rawok, &space);
+		    compressok || rawok, savedok, &space);
 		space -= resume_bytes;
 		if (fromsnap != NULL)
 			dsl_dataset_rele(fromsnap, FTAG);