From: Matthew Dillon <dillon@apollo.backplane.com>
Date: Wed, 10 Nov 2010 20:12:45 +0000 (-0800)
Subject: HAMMER utility - Handle pruning when only snapshot meta-data present
X-Git-Url: https://gitweb.dragonflybsd.org/dragonfly.git/commitdiff_plain/63948e839781ff95b7f762aa2bc8a7f14970a48c

HAMMER utility - Handle pruning when only snapshot meta-data present

* If only snapshot meta-data is present and no snapshot softlinks are found
  hammer prune (and hammer cleanup) previous exited with an error.  This case
  can occur when creating manual snapshot softlinks and/or trying to prune
  a slave PFS.

* In fact this is incorrect.  If meta-data is present we can prune based
  on that.
---

diff --git a/sbin/hammer/cmd_softprune.c b/sbin/hammer/cmd_softprune.c
index 4e63f583d2..7335cc2073 100644
--- a/sbin/hammer/cmd_softprune.c
+++ b/sbin/hammer/cmd_softprune.c
@@ -120,6 +120,15 @@ hammer_cmd_softprune(char **av, int ac, int everything_opt)
 		scan->prune.head.flags |= HAMMER_IOC_PRUNE_ALL;
 	} else {
 		hammer_softprune_scandir(&base, &template, *av);
+		if (base == NULL) {
+			const char *dummylink = "";
+			scan = hammer_softprune_addentry(&base, &template,
+							 *av, NULL, NULL,
+							 dummylink, dummylink);
+			if (scan == NULL)
+				softprune_usage(1);
+			scan->prune.nelms = 0;
+		}
 		++av;
 		--ac;
 	}
@@ -127,10 +136,6 @@ hammer_cmd_softprune(char **av, int ac, int everything_opt)
 	/*
 	 * XXX future (need to store separate cycles for each filesystem)
 	 */
-	if (base == NULL) {
-		fprintf(stderr, "No snapshot softlinks found\n");
-		exit(1);
-	}
 	if (base->next) {
 		fprintf(stderr, "Currently only one HAMMER filesystem may "
 				"be specified in the softlink scan\n");
@@ -185,6 +190,7 @@ hammer_cmd_softprune(char **av, int ac, int everything_opt)
 		}
 		if (scan->prune.nelms == 0 &&
 		    (scan->prune.head.flags & HAMMER_IOC_PRUNE_ALL) == 0) {
+			fprintf(stderr, "No snapshots found\n");
 			continue;
 		}
 
diff --git a/sbin/hammer/hammer.8 b/sbin/hammer/hammer.8
index ed007b2e56..7f4949a0cf 100644
--- a/sbin/hammer/hammer.8
+++ b/sbin/hammer/hammer.8
@@ -494,11 +494,15 @@ directive has a period of 0 and a retention time of 0
 then snapshot generation is disabled, removal of old snapshots are
 disabled, and prunes will use
 .Cm prune-everything .
+.Pp
 If the
 .Cm snapshots
 directive has a period of 0 but a non-zero retention time
 then this command will not create any new snapshots but will remove old
-snapshots it finds based on the retention time.
+snapshots it finds based on the retention time.  This form should be
+used on PFS masters where you are generating your own snapshot softlinks
+manually and on PFS slaves when all you wish to do is prune away existing
+snapshots inherited via the mirroring stream.
 .Pp
 By default only snapshots in the form
 .Ql snap- Ns Ar yyyymmdd Ns Op - Ns Ar HHMM