From: Antonio Huete Jimenez <tuxillo@quantumachine.net>
Date: Thu, 8 Jan 2015 11:30:05 +0000 (+0100)
Subject: hammer - Fix timeout for 'dedup' directive
X-Git-Tag: v4.2.0rc~1131
X-Git-Url: https://gitweb.dragonflybsd.org/~tuxillo/dragonfly.git/commitdiff_plain/3a92efe3ce8f11b83b469609135c5fedaafa6632

hammer - Fix timeout for 'dedup' directive

- 'hammer dedup' did not stop on timeout set by -t option.
- As the deduplication itself works by comparing one reference
  base element against a candidate base element, hammer(8) collects
  all the elements to be deduplicated and actually perform the needed
  ioctl() calls to make it happen. This is why the SIGALRM code has to
  be handled from within hammer(8).

Reported by: ftigeot
DragonFly-bug: <http://bugs.dragonflybsd.org/issues/2759>
---

diff --git a/sbin/hammer/cmd_dedup.c b/sbin/hammer/cmd_dedup.c
index 5b4d43d533..9314910f01 100644
--- a/sbin/hammer/cmd_dedup.c
+++ b/sbin/hammer/cmd_dedup.c
@@ -101,6 +101,7 @@ struct pass2_dedup_entry {
 #define DEDUP_PASS2	0x0001 /* process_btree_elm() mode */
 
 static int SigInfoFlag;
+static int SigAlrmFlag;
 static int64_t DedupDataReads;
 static int64_t DedupCurrentRecords;
 static int64_t DedupTotalRecords;
@@ -254,7 +255,9 @@ hammer_cmd_dedup(char **av, int ac)
 	struct dedup_entry *de;
 	struct sha_dedup_entry *sha_de;
 	struct pass2_dedup_entry *pass2_de;
+	char *tmp;
 	char buf[8];
+	int needfree = 0;
 
 	if (TimeoutOpt > 0)
 		alarm(TimeoutOpt);
@@ -266,6 +269,23 @@ hammer_cmd_dedup(char **av, int ac)
 
 	glob_fd = getpfs(&glob_pfs, av[0]);
 
+	/*
+	 * A cycle file is _required_ for resuming dedup after the timeout
+	 * specified with -t has expired. If no -c option, then place a
+	 * .dedup.cycle file either in the PFS snapshots directory or in
+	 * the default snapshots directory.
+	 */
+	if (!CyclePath) {
+		if (glob_pfs.ondisk->snapshots[0] != '/')
+			asprintf(&tmp, "%s/%s/.dedup.cycle",
+			    SNAPSHOTS_BASE, av[0]);
+		else
+			asprintf(&tmp, "%s/.dedup.cycle",
+			    glob_pfs.ondisk->snapshots);
+		CyclePath = tmp;
+		needfree = 1;
+	}
+
 	/*
 	 * Pre-pass to cache the btree
 	 */
@@ -333,7 +353,7 @@ hammer_cmd_dedup(char **av, int ac)
 	relpfs(glob_fd, &glob_pfs);
 
 	humanize_unsigned(buf, sizeof(buf), dedup_ref_size, "B", 1024);
-	printf("Dedup ratio = %.2f\n"
+	printf("Dedup ratio = %.2f (in this run)\n"
 	       "    %8s referenced\n",
 	       ((dedup_alloc_size != 0) ?
 			(double)dedup_ref_size / dedup_alloc_size : 0),
@@ -354,6 +374,15 @@ hammer_cmd_dedup(char **av, int ac)
                (intmax_t)dedup_successes_count,
                (intmax_t)dedup_successes_bytes
 	);
+
+	/* Once completed remove cycle file */
+	hammer_reset_cycle();
+
+	/* We don't want to mess up with other directives */
+	if (needfree) {
+		free(tmp);
+		CyclePath = NULL;
+	}
 }
 
 static int
@@ -813,6 +842,12 @@ done:
 	return (error);
 }
 
+static void
+sigAlrm(int signo __unused)
+{
+	SigAlrmFlag = 1;
+}
+
 static void
 sigInfo(int signo __unused)
 {
@@ -834,9 +869,27 @@ scan_pfs(char *filesystem, scan_pfs_cb_t func, const char *id)
 	DedupDataReads = 0;
 	DedupCurrentRecords = 0;
 	signal(SIGINFO, sigInfo);
+	signal(SIGALRM, sigAlrm);
 
+	/*
+	 * Deduplication happens per element so hammer(8) is in full
+	 * control of the ioctl()s to actually perform it. SIGALRM
+	 * needs to be handled within hammer(8) but a checkpoint
+	 * is needed for resuming. Use cycle file for that.
+	 *
+	 * Try to obtain the previous obj_id from the cycle file and
+	 * if not available just start from the beginning.
+	 */
 	bzero(&mirror, sizeof(mirror));
 	hammer_key_beg_init(&mirror.key_beg);
+	hammer_get_cycle(&mirror.key_beg, &mirror.tid_beg);
+
+	if (mirror.key_beg.obj_id != (int64_t)HAMMER_MIN_OBJID) {
+		if (VerboseOpt)
+			fprintf(stderr, "%s: mirror-read: Resuming at object %016jx\n",
+			    id, (uintmax_t)mirror.key_beg.obj_id);
+	}
+
 	hammer_key_end_init(&mirror.key_end);
 
 	mirror.tid_beg = glob_pfs.ondisk->sync_beg_tid;
@@ -905,8 +958,14 @@ scan_pfs(char *filesystem, scan_pfs_cb_t func, const char *id)
 			}
 		}
 		mirror.key_beg = mirror.key_cur;
-		if (DidInterrupt) {
-			fprintf(stderr, "Interrupted\n");
+		if (DidInterrupt || SigAlrmFlag) {
+			if (VerboseOpt)
+				fprintf(stderr, "%s\n",
+				    (DidInterrupt ? "Interrupted" : "Timeout"));
+			hammer_set_cycle(&mirror.key_cur, mirror.tid_beg);
+			if (VerboseOpt)
+				fprintf(stderr, "Cyclefile %s updated for "
+				    "continuation\n", CyclePath);
 			exit(1);
 		}
 		if (SigInfoFlag) {
@@ -938,6 +997,7 @@ scan_pfs(char *filesystem, scan_pfs_cb_t func, const char *id)
 	} while (mirror.count != 0);
 
 	signal(SIGINFO, SIG_IGN);
+	signal(SIGALRM, SIG_IGN);
 
 	free(buf);
 }