Allow for "zfs receive" to skip existing snapshots

by adding the option "-s" to zfs receive. Signed-off-by: Turbo Fredriksson <[email protected]> Closes: #2666
openzfs · Sep 8, 2015 · e108a79 · e108a79
1 parent 3b36f83
commit e108a79
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Showing 4 changed files with 55 additions and 10 deletions.
diff --git a/cmd/zfs/zfs_main.c b/cmd/zfs/zfs_main.c
@@ -247,9 +247,9 @@ get_usage(zfs_help_t idx)
 	case HELP_PROMOTE:
 		return (gettext("\tpromote <clone-filesystem>\n"));
 	case HELP_RECEIVE:
-		return (gettext("\treceive [-vnFu] <filesystem|volume|"
+		return (gettext("\treceive [-vnFus] <filesystem|volume|"
 		"snapshot>\n"
-		"\treceive [-vnFu] [-d | -e] <filesystem>\n"));
+		"\treceive [-vnFus] [-d | -e] <filesystem>\n"));
 	case HELP_RENAME:
 		return (gettext("\trename [-f] <filesystem|volume|snapshot> "
 		    "<filesystem|volume|snapshot>\n"
@@ -3856,7 +3856,7 @@ zfs_do_send(int argc, char **argv)
 }
 
 /*
- * zfs receive [-vnFu] [-d | -e] <fs@snap>
+ * zfs receive [-vnFus] [-d | -e] <fs@snap>
  *
  * Restore a backup stream from stdin.
  */
@@ -3867,8 +3867,11 @@ zfs_do_receive(int argc, char **argv)
 	recvflags_t flags = { 0 };
 
 	/* check options */
-	while ((c = getopt(argc, argv, ":denuvF")) != -1) {
+	while ((c = getopt(argc, argv, ":denuvFs")) != -1) {
 		switch (c) {
+		case 's':
+			flags.skip = B_TRUE;
+			break;
 		case 'd':
 			flags.isprefix = B_TRUE;
 			break;

diff --git a/include/libzfs.h b/include/libzfs.h
@@ -675,6 +675,9 @@ typedef struct recvflags {
 
 	/* do not mount file systems as they are extracted (private) */
 	boolean_t nomount;
+
+	/* skip existing snapshots */
+	boolean_t skip;
 } recvflags_t;
 
 extern int zfs_receive(libzfs_handle_t *, const char *, recvflags_t *,

diff --git a/lib/libzfs/libzfs_sendrecv.c b/lib/libzfs/libzfs_sendrecv.c
@@ -2874,13 +2874,14 @@ zfs_receive_one(libzfs_handle_t *hdl, int infd, const char *tosnap,
 		zfs_handle_t *zhp;
 
 		/*
-		 * Destination fs exists.  Therefore this should either
+		 * Destination fs exists (and we have not been asked to
+		 * skip existing snapshots). Therefore this should either
 		 * be an incremental, or the stream specifies a new fs
 		 * (full stream or clone) and they want us to blow it
 		 * away (and have therefore specified -F and removed any
 		 * snapshots).
 		 */
-		if (stream_wantsnewfs) {
+		if (stream_wantsnewfs && !flags->skip) {
 			if (!flags->force) {
 				zcmd_free_nvlists(&zc);
 				zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
@@ -2968,6 +2969,17 @@ zfs_receive_one(libzfs_handle_t *hdl, int infd, const char *tosnap,
 	zc.zc_begin_record = drr_noswap->drr_u.drr_begin;
 	zc.zc_cookie = infd;
 	zc.zc_guid = flags->force;
+
+	if (zfs_dataset_exists(hdl, zc.zc_value, ZFS_TYPE_SNAPSHOT) &&
+	    flags->skip) {
+		(void) printf("skipping snapshot %s - %s already exists\n",
+				drrb->drr_toname, zc.zc_value);
+		(void) fflush(stdout);
+
+		zcmd_free_nvlists(&zc);
+		return (recv_skip(hdl, infd, flags->byteswap));
+	}
+
 	if (flags->verbose) {
 		(void) printf("%s %s stream of %s into %s\n",
 		    flags->dryrun ? "would receive" : "receiving",

diff --git a/man/man8/zfs.8 b/man/man8/zfs.8
@@ -184,12 +184,12 @@ zfs \- configures ZFS file systems
 
 .LP
 .nf
-\fBzfs\fR \fBreceive | recv\fR [\fB-vnFu\fR] \fIfilesystem\fR|\fIvolume\fR|\fIsnapshot\fR
+\fBzfs\fR \fBreceive | recv\fR [\fB-vnFus\fR] \fIfilesystem\fR|\fIvolume\fR|\fIsnapshot\fR
 .fi
 
 .LP
 .nf
-\fBzfs\fR \fBreceive | recv\fR [\fB-vnFu\fR] [\fB-d\fR|\fB-e\fR] \fIfilesystem\fR
+\fBzfs\fR \fBreceive | recv\fR [\fB-vnFus\fR] [\fB-d\fR|\fB-e\fR] \fIfilesystem\fR
 .fi
 
 .LP
@@ -2934,11 +2934,11 @@ then the receiving system must have that feature enabled as well. See
 .ne 2
 .mk
 .na
-\fB\fBzfs receive\fR [\fB-vnFu\fR] \fIfilesystem\fR|\fIvolume\fR|\fIsnapshot\fR\fR
+\fB\fBzfs receive\fR [\fB-vnFus\fR] \fIfilesystem\fR|\fIvolume\fR|\fIsnapshot\fR\fR
 .ad
 .br
 .na
-\fB\fBzfs receive\fR [\fB-vnFu\fR] [\fB-d\fR|\fB-e\fR] \fIfilesystem\fR\fR
+\fB\fBzfs receive\fR [\fB-vnFus\fR] [\fB-d\fR|\fB-e\fR] \fIfilesystem\fR\fR
 .ad
 .sp .6
 .RS 4n
@@ -3017,6 +3017,33 @@ Do not actually receive the stream. This can be useful in conjunction with the \
 Force a rollback of the file system to the most recent snapshot before performing the receive operation. If receiving an incremental replication stream (for example, one generated by \fBzfs send -R -[iI]\fR), destroy snapshots and file systems that do not exist on the sending side.
 .RE
 
+.sp
+.ne 2
+.na
+\fB\fB-e\fR\fR
+.ad
+.sp .6
+.RS 4n
+Generate a more compact stream by using WRITE_EMBEDDED records for blocks
+which are stored more compactly on disk by the \fBembedded_data\fR pool
+feature.  This flag has no effect if the \fBembedded_data\fR feature is
+disabled.  The receiving system must have the \fBembedded_data\fR feature
+enabled.  If the \fBlz4_compress\fR feature is active on the sending system,
+then the receiving system must have that feature enabled as well. See
+\fBzpool-features\fR(5) for details on ZFS feature flags and the
+\fBembedded_data\fR feature.
+.RE
+
+.sp
+.ne 2
+.mk
+.na
+\fB\fB-s\fR\fR
+.ad
+.sp .6
+.RS 4n
+Skip existing snapshots in a stream.
+.RE
 .RE
 
 .sp